The system and method of the present invention includes an electrical to mechanical converter (EMC), such as a motor, and a hydraulic pump-and-cylinder arrangement that is connected to the electrical to mechanical converter for input, and to a sucker rod pump for output, in at least one embodiment. The entire assembly can be deployed below the level of the well fluid in a well. The EMC-driven hydraulic pump and cylinder can provide reciprocating linear motion to operate the sucker rod pump. In contrast, this linear motion is normally provided by sucker rods connected to a plunger inside a pump barrel and a pumping unit on the surface. The invention provides the required linear motion for the sucker rod pump to operate, but without the need for sucker and a surface pumping unit.

One of the most robust and dependable pieces of equipment in the oil extraction industry, commonly referred to as oil pumping, is the sucker rod pump. The sucker rod pumping system described is by far the most widely used of any artificial lift system. To simply describe the operation of the sucker rod pump is to describe the pumping cycle. Typically, a plunger inside a pump barrel of the sucker rod pump starts the upstroke actuated by the sucker rod, which in turn is actuated by a pumping unit on the surface. The weight of the liquid above the plunger will cause a one-way check valve, known as a "traveling valve," to close. Typically, the traveling valve is part of the plunger and, thus, travels with movement of the plunger. The upward motion of the plunger ("upstroke") will cause a reduction in pressure below the plunger in the lower portion of the pump. The pressure of the standing column of oil outside the pump will cause the oil to flow into a void in the lower portion of the pump created by the upstroke through another one-way check valve, known as a "standing valve."
As the motion of the plunger is reversed and the plunger starts downward ("downstroke"), the standing valve becomes closed. The pressure below the plunger increases and the traveling valve is opened. The fluid that previously entered through the standing valve flows upward through the traveling valve and into an upper portion of the pump above the plunger. On the next upstroke, the plunger displaces this fluid into the tubing above the pump. On successive cycles, an increment of fluid is displaced into the tubing, and eventually is discharged at the surface for further processing.
FIG. 1 is a schematic diagram of a prior art sucker rod pumping system. The figure illustrates one typical system by which produced fluids in a well are currently pumped from a subsurface depth of a well to the surface. The well generally includes a casing 12 installed into a well bore drilled into the earth and a conduit 15, generally termed "tubing," inserted into the casing for flowing fluids therethrough. One or more perforations 13 are formed in the casing to allow production fluids to enter the interior of the casing and be pumped to the surface. A sucker rod pump 30A, particularly an inlet of the pump, is installed below a fluid level 20 of the well so that fluid can enter the sucker rod pump and be pumped to the surface of the well through outlet 41 for further processing. A rod 24A, called the "thrusting rod," protrudes from the sucker rod pump axis.
A pumping unit 3 pivots rotationally, as shown by the curved motion arrows. This rotational pivoting action is leveraged into an up-and-down motion via one or more cables 6 from the pumping unit 3. The cables 6 are connected to a polish rod, which is connected to at least one sucker rod 9. An assembly of sucker rods creates a sucker rod string of a certain length. The up-and-down motion of the pumping unit is transmitted down the well through the sucker rods 9 to the sucker rod pump 30A.
As can be seen within the cutaway outline 18, the sucker rod 9 transmits its thrusting action via a joiner 21 to the rod 24A of the sucker rod pump 30A. The sucker rod is prone to failure. The failure can be attributed to a number of causes, but the repair of the rod string to return the well to operational status presents high costs to the operator. Not only is the cost of the equipment to be repaired significant, but the well servicing rig to pull and repair the sucker rod string represents a large portion of the repair. Further, when sucker rod wear on the interior of the tubing creates a leak in the tubing, that tubing must be repaired and tested to ensure integrity. The well servicing costs associated with sucker rod breaks and tubing leaks are a large part of the significant costs associated with rod pumped well failures.
A plunger (not shown) is coupled to the rod 24A inside the sucker rod pump 30A. The plunger has one or more one-way check valves (not shown), commonly called "traveling valves". As the rod 24A drives the plunger down in the downstroke, well fluid flows through these check valves. Once having flowed through these check valves, the well fluid is now in or on the top of the plunger. When the rod 24A downward motion reverses into an upstroke, the plunger lifts the well fluid up through a second set of one-way check valves 36, commonly called "standing valves," into the tubing 15. Also, as the plunger rises, well fluid is drawn into the lower part of the sucker rod pump via the inlet holes 33A. This same well fluid will move above the plunger on the plunger's downstroke.
Once well fluid is in the tubing 15, the one-way check valves 36 prevent the well fluid from returning into the sucker rod pump 30A. Additional well fluid is pumped into the tubing 15 with repeated cycles. With each new cycle, well fluid 39 is raised higher, eventually flowing to the surface and out the outlet 41 for further processing. This is the basic description of the prior art as to how well fluid is currently pumped from an oil well.
When the proper reciprocating linear motion is provided, this method of using a rod pump to pump fluid is dependable and has longevity. Longevity is important for components installed in an oil well, because the component may have to be brought to the surface from depths that may exceed a mile. Such operations are typically very costly from the service and from downtime in production.
Presently, the major disadvantage of a sucker rod pump system is that the linear force to drive the pump is from sucker rods emanating from the surface, which is often over a mile above the sucker rod pumps. These rods can weigh from one to three pounds per foot of depth and can easily weigh upwards of eight tons in many applications. Importantly, these tons of rods must not only be continuously supported, but their direction must be reversed for every stroke of fluid pumped.
The procedure is inefficient and requires a substantial energy input due to the frictional losses of the rods rubbing against the tubing in which they are encased, and the bearings of the pumping unit that have to rotate while under this constant support pressure. Also, the pumping unit, required to generate the reciprocating motion, is expensive and dangerous. Environmentalist groups claim that the pumping unit, which stands 25-40 feet high, is an eye sore. Further, surface pumping equipment, such as the pumping unit 3, can present problems in agricultural areas, because of the surface area required as well as vertical obstacles in farmlands where surface ground traversing irrigation systems are used.
There are other methods of artificial lift such as submersible centrifugal pumps, progressive cavity pumps, gas lift, and hydraulic pumping. The submersible centrifugal pumps are normally used for high volume applications, where the volume to be lifted exceeds rod pumping capabilities. These electrically driven centrifugal pumps utilize a series of impellers, which converts the centrifugal force on the fluid into pressure. Progressive cavity pumps are positive displacement pumps that can be driven by shafts rotated by motors on the surface, while some are actuated by submersible motors. Gas lift pumping utilizes natural gas as a lift mechanism either through continuous flow, intermittent flow, or plunger lift methods. Hydraulic pumping uses pumps on the surface to pressurize liquids, such as oil, to activate the downhole pump. Each type has its applications, but also problems unique to each type.
One significant problem that these other artificial lift technologies generally encounter is the high capital cost and excessive operating expenses when lifting low volume producing wells. This technology is unsuitable for most wells presently in operation in the United States, which produce less than 50 barrels of oil and water per day. Another problem is the life of the equipment or the duration of service without major maintenance, which, while quite short, may be acceptable for high volume applications that can justify expensive maintenance.
Another design idea has been proposed that includes a motor down in the well near the fluid level, where the motor can turn a threaded shaft upon which a nut-like assembly is attached. As the threaded shaft rotates, the nut-like assembly moves linearly up the shaft. This nut-like assembly is connected to the input rod of the rod pump. The direction of rotation of the threaded shaft is reversed when the chamber of the rod pump is at its largest. Then, the nut-like assembly will move down the threaded shaft, forcing the input rod back into the rod pump and the chamber size will shrink, thereby pumping the fluid. The motor can continue to alternate reversing its rotation to reverse the rotation of threaded shaft to continue to pump the fluid.
While the nut on thread process may be theoretically possible, there are several drawbacks in its practical implementation. First, this mechanism wears out relatively quickly, far short of the required number of reciprocations for a standard well, even using ball bearings in the threaded nuts. The second failing is that a motor which can reverse direction is inherently less efficient, more expensive, and more maintenance prone. The goal of a low maintenance system over the life of the well is compromised.
Thus, there remains a need for an improved pumping system that targets low volume applications with low capital investment and long life between repairs.


An actuating drive for a plasticizing unit of an injection molding machine is disclosed. The actuating drive includes a spindle drive with an electric motor and a control mechanism. An energy storage device is coupled with the spindle drive for force transmission therebetween. The energy storage device is loaded by the spindle drive in a return stroke phase and is unloaded in a forward feed phase, boosting the power of an electric motor. The actuator drive can be used, for example, for pulsating actuation of a mold ejector of the injection molding machine, significantly reducing the electrical energy consumption compared to conventional drives.

The present invention relates to an actuating drive for a plasticizing unit of an injection molding machine, and more particularly to an actuating drive with a spindle drive for pulsating actuation of a mold ejector to reduce the electrical energy consumption of the spindle drive.
International patent publication WO 97/34757 describes a spindle drive operating as an actuating drive for an injection molding machine. The actuating drive includes an electric motor and, for relieving the electric motor in the feed phase, an energy storage device in the form of a compression spring assembly arranged in parallel with the electric motor. The load on the compression spring assembly increases during the return stroke of the spindle drive, whereas the spring force continuously decreases during the spindle forward feed stroke in conformance with the characteristic spring curve. However, the relief provided by the energy storage device is significantly reduced in that the characteristic spring curve of the energy storage device does not conform to the force and speed requirements of a plasticizing drive which can vary significantly depending on the stroke and can therefore negatively effect the total energy consumption of the drive unit. If the spindle drive is used as an actuating drive for the plasticizing screw, then the spindle drive has to be held by the electric motor at the return stroke position during the time between mold filling and injection process, counteracting the then maximum forward feed force of the energy storage device. Moreover, the motor also has to supply the force difference required for building up the necessary counter-pressure in the initial phase of the mold filling process, i.e., in the region of the forward stroke position of the plasticizing screw, where the spring force is minimal. The same applies when a spindle drive of this type is used as an actuating drive for the entire plasticizing unit: while the plasticizing unit is stopped in the return stroke position, the spindle drive has to be held by the electric motor in a stationary state against the maximum spring force. The electric motor also has to generate the injection force of the injection nozzle on the sprue bush of the injection tool during the entire duration of the injection process when the plasticizing unit is in the forward feed position. As a result, the compression spring assembly reduces the power required by the electromotive spindle drive only in a limited way.
It would therefore be desirable and advantageous to provide an improved plasticizing unit of simple construction, which obviates prior art shortcomings and is able to specifically reduce the power requirements of the electromotive spindle drive.

Plasticizing unit with an electromotive spindle drive for an injection molding machine


A method for designing a wireless telecommunications system having a plurality of cells is provided. In one embodiment of such a method, a call demand per cell is estimated, and a channel demand based thereon is determined on a cell-by-cell basis. The cell-by-cell channel demand is used to provide a reasonably tight upper bound on the number of communication channels required to satisfy the system-wide call demand. It is implicit in the procedure for estimating the upper bound that no mutually "interfering" base stations use the same channel (i.e., frequency). "Cliques" of mutually-interfering base stations or cells are defined. A channel demand is determined for each clique by adding up the channel demand for each cell in the clique. The greatest channel demand of all cliques determines a "maximum clique demand" .omega..sup.d. The upper bound on the number of channels required to satisfy the system-wide call demand is given by the expression: .chi..sup.d .ltoreq.17/12.multidot..omega..sup.d when mutually-interfering cells are adjacent cells, and is given by the expression: .chi..sup.d .ltoreq.2.multidot..omega..sup.d -d.sub.min when mutually interfering cells are adjacent cells and next-to-adjacent cells, wherein d.sub.min is a minimum channel demand of all cells in the system. Having a reasonably-good estimate of the upper bound on the system-wide channel requirement, a wireless service provider may then seek to obtain or allot a commensurate amount of frequency spectrum to support its system.

FIG. 1 depicts a schematic diagram of a portion of a typical wireless telecommunications system in the prior art. Such a system provides wireless telecommunications service to a number of wireless terminals (e.g., wireless terminals 101-1 through 103-1) that are situated within a geographic region.
The heart of a typical wireless telecommunications system is Wireless Switching Center ("WSC")120, which may also be known as a Mobile Switching Center ("MSC") or a Mobile Telephone Switching Office ("MTSO"). Typically, WSC 120 is connected to a plurality of base stations (e.g., base stations 103-1 through 103-5) that are dispersed throughout the geographic area serviced by the system. Additionally, WSC 120 is connected to local- and toll-offices (e.g., local-office 130, local-office 138 and toll-office 140). WSC 120 is responsible for, among other things, establishing and maintaining calls between wireless terminals and between a wireless terminal and a wireline terminal, which is connected to the system via the local and/or long-distance networks.
The geographic area serviced by a wireless telecommunications system is partitioned into a number of spatially-distinct areas called "cells." As depicted in FIG. 1, each cell is schematically represented by a hexagon; in practice, however, each cell usually has an irregular shape that depends on terrain topography. Typically, each cell contains a base station, which comprises radios and antennas that the base station uses to communicate with the wireless terminals in that cell and also comprises the transmission equipment that the base station uses to communicate with WSC 120.
As an example of wireless telecommunications, when wireless terminal 101-1 desires to communicate with wireless terminal 101-2, wireless terminal 101-1 transmits the desired information to base station 103-1, which relays the information to WSC 120. Upon receiving the information, and with the knowledge that it is intended for wireless terminal 101-2, WSC 120 then returns the information to base station 103-1, which relays the information, via radio, to wireless terminal 101-2.
The wireless telecommunications described above occur over a plurality of communication channels. Such channels are characterized by a carrier frequency, and a bandwidth (e.g., 30 kHz) over which the carrier frequency is modulated to carry information content. Wireless service providers license, at a very substantial cost, a band of frequency spectrum sufficient to provide an adequate number of communication channels for supporting communications within a given wireless system.
The amount of spectrum that a provider must obtain to support such communications is predominantly a function of (1) the amount of spectrum that a channel consumes, (2) the extent to which channels used in any one of the cells can be reused in other cells, (3) the call traffic ("call demand" or "traffic demand") on the system, and (4) the acceptable percentage of blocked call attempts. Regarding (2), channel reuse is limited by channel interference. Such interference, which may occur between cells ("co-channel interference") and between numerically-consecutive or nearly-consecutive carrier frequencies ("adjacent-channel interference"), must be kept within acceptable limits.
Since spectrum is very expensive, it is disadvantageous for a provider to license substantially more spectrum than is required for supporting communications within its wireless telecommunications system. As such, it would be advantageous to have a good estimate of that spectrum requirement. Unfortunately, little guidance is available for estimating the spectrum requirements for a wireless telecommunications system. One reason for the dearth of information on the subject may be the difficulty of estimating such requirements, which may be abstracted as a generalization of the notoriously difficult problem of graph "coloring." In fact, frequency spectrum estimation adds an additional degree of complexity to the already complicated standard graph coloring problem.

Wireless telecommunications system and method for designing same


A golf swing improvement device that includes two adjustable wrist encircling members, a golf club gripping member capable of fitting on any golf club, and a stretchable, flexible linear portion having two end areas. One of the end areas is attached to one of the wrist encircling members and the other end area is attached to the other wrist encircling member. A central area of the linear portion is firmly held by the golf club gripping member so that the length of linear portion extending between each wrist encircling member and the golf club gripping member may be separately adjusted in length.

1. Field of the Invention
This invention relates to devices for improving a golfer's game, and in particular, relates to a golf swing improvement device.
2. Description of the Related Art
The difficulty of achieving a proper golf club swing has been addressed by numerous types of inventions, related to such various components of swing as the golfer's hand position, angle of golf club, follow-through of the swing, and the like. For example, there are various hand positioning guides including those of Carlisle (U.S. design Pat. No. D361,613) and Harkins, Jr. (U.S. design Pat. No. D354,327).
The golf club alignment guide of Hirsch (U.S. Pat. No. 5,413,329) is a detachable stand for supporting a golf club that includes a triangular-shaped bracket member pivotally supporting a spring clamp adapted to clamp the shaft of a golf club so that the golf club is supported in an upright position at an angle selected by player.
The golf club swing training device of Huber (U.S. Pat. No. 4,664,388) comprises a ball suspended by a cord from a handle or from the shaft of a golf club for use in a set of drill steps intended to teach a proper golf swing, through utilization of the centrifugal forces required in a proper golf swing.
The golf swing training aid of Slusher (U.S. design Pat. No. D356135) appears to include a hand-piece clampingly mounted parallel to a golf club handle so the person holds two separate handles during the training.
The golf swing control strap of del Barrio (U.S. design Pat. No. D372,064) include a buckled strap apparently for encircling an arm, attached perpendicularly to a buckled vertical strap that is attached to a small curved piece, presumably for encircling a golf club handle.
None of the known inventions provide a means for flexibly positioning both of the golfer's hands to assist the golfer in keeping the hands in correct position with correct follow-through in the swing. It is therefore an object of the invention to provide a device which gives a user the correct positioning of hands and wrists, and thus allows improvement of the accuracy of the person's game.
Other objects and advantages will be more fully apparent from the following disclosure and appended claims.


A device for detecting household conditions and events includes a power supply portion and a plurality of portions able to detect different conditions, or changes in different conditions. Each detecting portion includes an input port and an output port, the output port of one detecting portion is detachably electronically connected to the power supply portion, and the input port of one detecting portion is detachably electronically connected to the output port in a modular fashion of another detecting portion, the remote selection of a specific required detection is also provided.

Generally, a detecting device can only detect a single and specific condition, limiting detection to applicable scenarios. When multiple conditions need to be detected or composite detection is required, one detecting device is often not enough. Several detecting devices are needed, which is not only inconvenient, but also increases cost.

Detecting device having a plurality of detecting portions working automatically or by selection

HONG FU JIN PRECISION INDUSTRY (WuHan) CO., LTD.


Multiple stacks of tubular electrochemical cells having a dense electrolyte disposed between an anode and a cathode preferably deposited as thin films arranged in parallel on stamped conductive interconnect sheets or ferrules. The stack allows one or more electrochemical cell to malfunction without disabling the entire stack. Stack efficiency is enhanced through simplified gas manifolding, gas recycling, reduced operating temperature and improved heat distribution.

1. Field of the Invention
This invention pertains generally to solid-state electrochemical device assemblies, and more particularly to a modular parallel electrochemical cell in series stack.
2. Description of Related Art
Steadily increasing demand for power and the atmospheric build up of greenhouse and other combustion gases has spurred the development of alternative energy sources for the production of electricity. Fuel cells, for example, hold the promise of an efficient, low pollution technology for generating electricity. Because there is no combustion of fuel involved in the process, fuel cells do not create any of the pollutants that are commonly produced in the conventional generation of electricity by boilers or furnaces and steam driven turbines.
Unfortunately, the present cost of electrical energy production from fuel cells is several times higher than the cost of the same electrical production from fossil fuels. The high cost of capitalization and operation per kilowatt of electricity produced has delayed the commercial introduction of fuel cell generation systems.
A conventional fuel cell is an electrochemical device that converts chemical energy from a chemical reaction with the fuel directly into electrical energy. Electricity is generated in a fuel cell through the electrochemical reaction that occurs between a fuel (typically hydrogen produced from reformed methane) and an oxidant (typically oxygen in air). This net electrochemical reaction involves charge transfer steps that occur at the interface between the ionically conductive electrolyte membrane, the electronically-conductive electrode and the vapor phase of the fuel or oxygen. Water, heat and electricity are the only products of one type of fuel cell system designed to use hydrogen gas as fuel. Other types of fuel cells that have been developed include molten carbonate fuel cells, phosphoric acid fuel cells, alkaline fuel cells, proton exchange membrane fuel cells. Because fuel cells rely on electrochemical rather than thermomechanical processes in the conversion of fuel into electricity, the fuel cell is not limited by the Carnot efficiency experienced by conventional mechanical generators.
Solid-state electrochemical devices are normally cells that include two porous electrodes, the anode and the cathode, and a dense solid electrolyte membrane disposed between the electrodes. In the case of a typical solid oxide fuel cell, the anode is exposed to fuel and the cathode is exposed to an oxidant in separate closed systems to avoid any mixing of the fuel and oxidants due to the exothermic reactions that can take place with hydrogen fuel.
The electrolyte membrane is normally composed of a ceramic oxygen ion conductor in solid oxide fuel cell applications. In other implementations, such as gas separation devices, the solid membrane may be composed of a mixed ionic electronic conducting material ("MIEC"). The porous anode may be a layer of a ceramic, a metal or, most commonly, a ceramic-metal composite ("cermet") that is in contact with the electrolyte membrane on the fuel side of the cell. The porous cathode is typically a layer of a mixed ionically and electronically conductive (MIEC) metal oxide or a mixture of an electronically conductive metal oxide (or MIEC metal oxide) and an ionically conductive metal oxide.
Solid oxide fuel cells normally operate at temperatures between about 900° C. and about 1000° C. to maximize the ionic conductivity of the electrolyte membrane. At appropriate temperatures the oxygen ions easily migrate through the crystal lattice of the electrolyte. However, most metals are not stable at the high operating temperatures and oxidizing environment of conventional fuel cells and become converted to brittle metal oxides. Accordingly, solid-state electrochemical devices have conventionally been constructed of heat-tolerant ceramic materials. However, these materials tend to be expensive and still have a limited life in high temperature and high oxidation conditions. In addition, the materials used must have certain chemical, thermal and physical characteristics to avoid delamination due to thermal stresses, fuel or oxidant infiltration across the electrolyte and similar problems during the production and operation of the cells.
Since each fuel cell generates a relatively small voltage, several fuel cells may be associated to increase the capacity of the system. Such arrays or stacks generally have a tubular or planar design. Planar designs typically have a planar anode-electrolyte-cathode deposited on a conductive interconnect and stacked in series. However, planar designs are generally recognized as having significant safety and reliability concerns due to the complexity of sealing of the units and manifolding a planar stack.
In addition, conventional stacks of planar fuel cells operated at the higher temperature of approximately 1000° C. have relatively thick electrolyte layers compared to the porous anode and cathode layers applied to either side of the electrolyte and provides structural support to the cell. However, in order to reduce the operating temperature to less than 800° C., the thickness of the electrolyte layer has been reduced from more than 50-500 microns to approximately 5-50 microns. The thin electrolyte layer in this configuration is not a load bearing layer. Rather, the relatively weak porous anode and cathode layers must bear the load for the cell. Stacks of planar fuel cells supported by weak anodes or cathodes may be prone to collapse under the load.
Tubular designs utilizing long porous support tubes with electrodes and electrolyte layers disposed on the support tube reduce the number of seals that are required in the system. Fuel or oxidants are directed through the channels in the tube or around the exterior of the tube. However, tubular designs provide less power density because of the relatively long current path on the electrodes since the current collection for the entire tube occurs on only a small area on the circumference of the tube. This contributes to internal resistive losses thereby limiting power density.
In addition, the concentration of the reactants often diminishes as gas flows through the channels along the length of the tubes if an insufficient volume of reactants is directed through the apparatus. Decreased gas concentration at the anode, for example, will result in a reduction in the electrical output of the cell depending on the position of the cell in the stack. Increasing the volume of fuel or oxidants flowing through the apparatus may result in excess reactants exhausting the system along with the reaction products of the electrochemical device. Excess reactants are typically burned to provide operating heat for the solid fuel cells in conventional devices. Excess reactants that exhaust the system and are burned further reduce the efficiency of the apparatus.
Another significant problem encountered with planar stacks with repeating cell elements is that the failure of one cell may result in the failure of the entire stack. Malfunctioning cells in present designs may require cooling the stack and taking it off line to replace a single cell.
Thus, present solid-state electrochemical devices incorporating conventional designs are expensive to manufacture and may suffer from safety, reliability, and/or efficiency concerns.
Accordingly, there is a need to provide a stack or array of electrochemical devices, such as solid oxide fuel cells, that are capable of operating efficiently at lower temperatures and use less expensive materials and production techniques. Stack designs that reduce the cost of materials and manufacturing while increasing the reliability of fuel cells and other solid state electrochemical devices, may allow for the commercialization of such devices that have been previously too expensive, inefficient or unreliable to exploit. The present invention satisfies these needs, as well as others, and generally overcomes the deficiencies in conventional devices.

The Regents of the University of California


A machine for terminating electric cable has a feeding segment that is decoupled from a terminating segment. The feeding segment has two feeders on which electric cable is wound. A length of cable is paid off one feeder and cut to length while another length of cable that has been paid off another feeder and cut to length is terminated at least at one end of the cable. A process for terminating electric cable provides a cable feed comprising a plurality of feeders and pays off a length of cable from one feeder of the cable feed while another length of cable that has been paid off another feeder of the cable feed is terminated at least at one end of the another length of cable. Alternatively lengths of cable are paid off two feeders and accumulated in a buffer segment associated with a feeding segment and a terminating segment. In an alternative process several lengths of cable are cut off and accumulated in a buffer while several other lengths of cable are being terminated.

Electric cable is generally manufactured in very long lengths that are wound on a drum or reel for sale and/or transportation. For practical use, a length of electric cable is cut off the end of the electric cable that is wound on the drum and often another operation is performed at one or both ends of the cut-off length of cable. For high volume production in a factory, individual lengths of electric cable are processed in various ways in machines and processes that all involve paying off a length of electric cable from a drum or reel and cutting off the length of the paid-off cable for further processing. Further processing, such as stripping one or both ends of the cable, attaching a cable seal at one or both ends of the cable, and/or attaching a terminal at one or both ends of the cable, is generally referred to as terminating. Stripping, applying seals and applying terminals are only some of the many processing steps that can also be included in the terminating process.
The known machines and processes are generally of three types, a swing arm type, a transport arm type and a combination of a swing arm and a transport arm type. These known machines and processes comprise two segments, a feeding segment and a terminating segment with cutting off a length of paid off cable being the link between the two segments.
A problem with the known machines and processes of the above types is that the operation of the two segments are sequentially linked, so that one segment must wait to start its processing until the other segment has completed its operation. Consequently, one of the segments is idle a significant amount of time.
In such machines and processes, the cycle time that it takes from a finished electric cable to the next is the sum of the time each segment of the machine or process requires to process each part. Particularly the feeding time is directly proportional to the length of cable being processed, so that the problem increases with the length of electric cable that is to be paid off the reel.

Multiple wire feed machine and process for terminating electric cable


A safety-related control system (SRCS) designed to safeguard personnel operating hazardous production equipment. The SRCS integrates the safety-related part of a machine into one homogenous system for the purpose of increasing safety. In so doing, the SRCS monitors the machine, the operator, and itself for safe operation. The SRCS utilizes a non-material barrier to sense the intrusion of a person's body into a hazardous area of a machine. The SRCS uses machine feedback and/or operator interface to determine whether a hazardous condition is present. If such condition is present, the hazard is rendered harmless by the time the intruding body member can reach the potential danger area. The system includes separable means for stopping motion of the moving parts of the equipment, starting movement of the movable parts, and detecting faults in sections of the system.

1. Technical Field
The present invention relates to improved safety of production equipment by integration of a machine's safety-related parts and safety-related control into one homogeneous safety-related control system (SRCS), where the machine, operator, and SRCS are continuously monitored and whereby any fault within the SRCS is discovered within the system's response time. More particularly, the present invention relates to a system of interrelated electrical, sensing, and mechanical modules designed and deployed to sense the intrusion of an object into a controlled space and upon such sensing to initiate a proper machine control signal, based on the event taking place at the machine. The machine signal is monitored to ensure that it achieved its intended safety function. Still more particularly, the present invention relates to an improved machine safety control that interfaces with 1) an electrosensitive sensing device, 2) safety mechanism initiation devices, 3) safety mechanism monitoring means, and 4) safety mechanism event control means.
2. Description of the Prior Art
Prior art views the machine safety system as an assemblage of component parts that together create a safety system. Standard devices used in such safety systems may include a two-hand control, an electro-sensitive protective device, a safety control, a protective light curtain, a motion monitor, a position monitor, a machine primary control element monitor, a machine control interface, a stop position monitor, or a brake monitor. Various combinations of these standard devices may be used in a given safety system. Each of these devices has a response time which is safety-critical in that it must fulfill its function in the stoppage of the press or other machine as a hand or other body part is rushing into a hazardous area. If even one device in the chain fails to respond within its proper time frame, the press will not stop in time to prevent injury. Most high-integrity devices of this nature have their response times monitored; however, because each is an independent stand-alone component, the response time can only be measured from the elapsed time that the component received its input to some specified time after its output was to occur. For fault-tolerant reasons, it is desirable to allow sufficient time, after the normal response time of the device, for monitoring the device's state. This additional time is to allow the mechanical parts of the output device or devices to come to a complete rest.
Furthermore, since most of these devices are monitored only for a complete failure to change state within an allotted time period, the actual response time of the device itself cannot be determined. For example, if a safety device with a normal response time of 5 mS is allocated 100 mS as its upper limit for determining a complete failure, then it can be difficult to determine the exact response time of that device. The actual response time could be 5 mS?, 25 mS?, 50 mS?, or 99 mS? There is no way to be sure. In an isolated incident, such ambiguity may not be all that safety-critical because of the margin-of-safety designed within the parameters of a particular employment of the device, however, such ambiguity would likely present various problems if allowed in a multiple safety device system.
A major problem occurs when individual components are linked in a chain of events and each component is monitored only for complete failure to change state. If there is no system for checking the actual overall response time of each event in the chain of events with respect to the start of the event (e.g. sensing function), the machine may accumulate response time error, and the component will validate its own output state at some elapsed time after its input signal. An individual component cannot detect whether its input signal was late and so it may erroneously validate its output signal at some extended period of time after it should have normally responded. Thus, the response time errors are allowed to accumulate. There is no opportunity to cure or detect that accumulation and so the overall stop time may become hazardously long.
Accumulative response time failures can occur in all of the following mechanisms:
1. Delay in code generation for polling light beam channels of a light curtain system. PA0 2. Delay in light beam channel being polled. PA0 3. Delay in sequencing to next light beam channel. PA0 4. Delay in completing full scan of all light beam channels. PA0 5. Delay in processing receiver signal. PA0 6. Delay in transmitting output signal to relay coil of Output Signal Switching Device (OSSD). PA0 7. Delay in OSSD energizing/de-energizing. PA0 8. Delay in OSSD contacts opening/closing. PA0 9. Elapsed time between OSSD input versus verification of OSSD output. PA0 10. Delay in FSD's coil energizing/de-energizing. PA0 11. Delay in FSD's contacts opening/closing. PA0 12. Elapsed time between FSD's input versus verification of output. PA0 13. Delay in Machine Primary Control Element's (MPCE's) energizing/de-energizing. PA0 14. Delay in MPCE's movable opening/closing. PA0 15. Elapsed time between MPCE's input versus verification of output. PA0 16. Delay in Stop Performance Monitoring (SPM) output signal. PA0 17. Delay in SPM processing. PA0 18. Elapsed time between SPM input versus output calculation.
The electrosensitive protection device's change of state is the event which starts the chain of events to occur and should be the event in which all interim switch elements are clocked.
Typically, an electrosensitive protection device's signal processing circuit functions at a fixed "off"/"on" threshold level. The optical receiving elements, upon receiving a certain amount of radiation from their corresponding emitting elements, produce an illuminated "on" signal upon an object, such as a hand blocking a certain percentage of light, and the amplitude of the illuminated signal drops. Hopefully it drops to the "off" threshold level and the signal processing circuitry produces a machine stop signal.
The problem with this fixed "off" threshold level is that the amount of radiation needed to be removed from the receiving element is a function of the amplitude of the illuminated signal. For instance, a system with a fixed "off" threshold of 50 mV and an amplitude of an illuminated signal of 150 mV would require a blockage of radiation equivalent to 100 mV to reach its fixed "off" threshold. Conversely, the same system with an amplitude of an illuminated signal of 12 V would require blockage of radiation equivalent to 11.05 V to reach its fixed "off" threshold. For light curtain systems this radiation is generally produced by infrared light beams. In the first scenario, very little of the light beam had to be blocked to reach the "off" state. However, in the second scenario, the entire light beam needs to be obscured before reaching the "off" state. Assuming the beam diameters are the same size, it would require a much larger object to obscure all of the light beam in second scenario than in first scenario.
This problem is further exacerbated by the physics of the spectral relationship of light in which the beam spreads in a conical pattern over space. This results in two spin off problems. First, the beam diameter becomes larger as the distance between the emitter and receiver increases. Thus if the signal amplitude remains constant, the object size required to obscure the entire beam diameter increases, therefore the detection capabilities become application dependent, i.e. detection capabilities increase when distance increases. Second, the increased beam diameter can be reflected off nearby surfaces and rerouted to the receiver failing to detect the intruding object.
The problem is further exacerbated by the fact that photodetector elements are simple devices, they simply react to the presence or absence of light, thus other ambient light sources can create this rise in signal amplitude. Furthermore, ambient light is produced by various sources found in the common industrial workplace, i.e. sun, fluorescent lamps, halogen strobes, remote control devices, photoelectric devices and the like. This rise in signal amplitude will now require that enough of the normal system light plus the ambient light (which may be coming from a different direction) be obscured by the object in order to reach the fixed "off" threshold. This problem is even further exacerbated by systems that amplify their received light signal for transmission to the signal processing circuit. Such systems may amplify ambient light when the source is obscured, thus appearing as an unobstructed signal.
This problem is still further exacerbated if the photodetector circuitry is allowed to go into saturation, an event whereby the photodetector is being struck with so much light that it passes its entire supply current or voltage. The problem here is that no one knows how far into saturation the detector has gone, thus no one knows how much radiation is required to get it out of saturation nor how much reduction of radiation is required to drop the signal to its fixed "off" threshold. For example, saturation can be analogous to a water valve with the water being substituted for electricity (i.e. velocity and volume i.e. current and voltage i.e. PSI). The water valve may be half open at five turns, at which point, it passes all the water supplied to it. This is the valve's saturation level. One may continue turning the valve until it is fully opened, 10 turns, but no greater volume of water would flow. Someone else, who wanted to reduce the flow of water, would have no knowledge of how far they had to turn the valve before reaching the analog state of water flow.
Closed shorts between emitting devices and/or detecting devices in multichannel light curtain systems could result in detection capability loss. For instance, if a short was across adjacent LED emitters they could both turn on simultaneously, and as their light beams conically expand over space, each beam could be striking the intended detector. Similarly, if a short was across adjacent detectors, both detectors could produce an illuminated signal based on one LED emitter being on due to the conical expansion of the beam being large enough to cover both detectors. Either situation could endanger the operator, because an intrusion into the light array may go undetected.
The signal processing circuitry of a light curtain system may reliably detect an intrusion into its sensing zone, however, there is no assurance that its output circuitry has the ability to change state and thus achieve the desired result. The system must test itself to ensure that any intrusion results in an output state. For real-time continuous systems, this test must ensure that the response time of the output state is maintained.
Prior art demonstrates the use of redundant output devices which are monitored for a switching state using a method remote of the safety control system. The primary problem with this method is that the state of the output device is monitored without regard to the time it took to change its state in relationship to the event (i.e. blockage of light curtain) that commanded the change of state, thus the device may respond but may respond too late to prevent injury.
As a secondary problem, prior art devices rely on one of two output devices changing states. With the failure of one device, the other device performs the machine stop function, and the remote monitoring control prevents re-energization of the non-failing device thus resulting in a lockout condition. For a higher safety integrity system, "common cause failures" such as an electrical surge, burst, dip, etc., or an electromagnetic disturbance, EMI, RFI, ESD, etc., must be overcome.
Current stop performance monitors are used primarily on mechanical presses as a means to identify that the brake mechanism is wearing down and the machine no longer stops within its original requirements. Typically this is accomplished by initiating a stop command shortly before the press's ram has reached top of stroke, at which point, a signal is sent from the press's cam to initiate the brake and disengage the clutch. A second signal from the cam is then read to determine the cam's angular displacement. In the event this signal exceeds its parameters, and the ram has gone beyond top of stroke, an alarm is actuated. The problem with this verification method is that it does not monitor the response time of the switching elements in the chain of the real stop command, thus accumulated response time errors are not detected.
For cyclical machines that have a potentially hazardous half-cycle and virtually nonhazardous half-cycle (i.e. presses), it would be desirous to have the operator be able to reach into the machine during the nonhazardous time to extract parts. To achieve this objective, a light curtain must be bypassed (muted) during the nonhazardous half-cycle in order to not send a stop command to the machine's moving parts. This is potentially a very dangerous practice if in the event of malfunction the mute function was not turned off during the hazardous portion of the machine cycle and/or if the hazard/non-hazard portion of a machine cycle were reversed.
Prior art demonstrates how to achieve the muted state by using position sensors that interface with the machine's control system. Upon receiving a signal from the sensors, the control system energizes a bypass relay located in the current path of the light curtain's output devices so that during the nonhazardous half-cycle, a light curtain detecting an intrusion does not produce a stop output. However, the signal never reaches the MPCEs because the interposing bypass relay is rerouting the current flow to the MPCEs. The position sensors for presses are located at the top of the ram stroke and at the bottom of the ram stroke. The sensor at the bottom of the stroke initiates the muted condition and the one at the top of the stroke disengages the muted condition.
From the standpoint of high safety integrity this is a flawed system, one which uses single-channel techniques whereby any single failure of numerous devices could result in danger. For example, the interposing bypass relay used to keep the MPCE energized could fail in the "on" state, thereby removing the safety light curtain function during the hazardous half-cycle. The top sensor could also fail, thus not turning "off" the muted condition. The position sensors could be physically inverted, creating a bypass of the safety devices during the hazardous half-cycle. The machine control input signal from the position sensor could fail in a muted condition, and the machine's output signal could fail in a muted condition resulting in a similar danger to the operator.
Typically, the start actuator of a machine is a simple "on"/"off" switch, which when manually placed in the "on" position remains there until manually switched to the "off" position. From the standpoint of safety, this type of switch configuration is flawed. For example, in the event of power interruption of the source, the machine would automatically stop, and when the source power is restored, the machine will be put in motion. This situation is very dangerous for an operator or maintenance person who may be troubleshooting the cause of shut down in the hazard area. This type of switch configuration is further flawed by the fact that the switch is not interactive with the safety control system. The safety system cannot effect it upon system failure. This configuration is still further flawed in the event the machine system has a bypass, i.e. mute, which may bypass the safety system based on de-energizing one or more relays.
Typically, two-hand control devices are stand alone safety devices that when actuated initiate machine motion. Typically these devices have a circuit to ensure neither actuator is fastened down (thus allowing for single-hand control) and that they both are actuated within a specified time of each other. These devices must be kept depressed during the hazardous cycle (i.e. downward stroke of the machine). Failure to keep both actuators depressed will result in machine stoppage. This system is flawed in the respect that many failures can occur which would jeopardize safety integrity, such as the commingling of safety lines in which one-hand control produces both signals due to cross interference.
Presence-sensing Device Initiation (PSDI) is a method of initiation of the machine cycle upon interruption and restoration of the light curtain's sensing zone. During the nonhazardous portion of the machine cycle, the operator reaches into the machine's hazard area to remove the product thereby creating an interruption and restoration of the sensing zone of the light curtain. PSDI functions in either a single break mode (as described above) or a double break mode in which the operator enters and leaves the detection zone twice (removing the finished product and inserting new material).
This mode of operation can be extremely dangerous because the sensing function of the light curtain is governing the machine initiation, not the operator. In the event of malfunction of the light curtain, interfacing control system, machine position sensors, machine feedback signals, or any of the above response times, the machine could initialize a cycle suddenly and abruptly.
The prior art has addressed this mode of operation primarily by way of avoidance. In the isolated cases in which it has been implemented, the onus of safety has been put on the machine installer via programming the machine control's PLC (Programmable Logic Control). This is flawed in the respect that the PLC is not a safety control. The PLC does not have a physical structure of redundancy and comparison, and thus failures go undetected. This mode of operation is further flawed in that it assumes the programmer is familiar with the safety techniques and measures needed to ensure high level safety integrity of the software and how to implement software tests.
There are six basic modes of operations in which light curtain systems interface with the machine based on how the operator is to interact with the machine. Establishing a functional interrelationship of the safety-related parts with the other functional parts of the machine has traditionally been done by interfacing the safety-related parts with the machine control. In this solution, the safety systems default their safety-related integrity to the machine control (i.e. PLC). From the standpoint of high-level safety integrity this method is flawed. The PLC is not structured with two-channels where each channel performs its safety-related function independent of the other by comparing its result with the other and any disparity resulting in a lockout. In addition, the machine control has no knowledge of the start of the event (i.e. last unblocked light curtain scan). Therefore it has no way to verify accumulated response time errors. Also, because the machine control is programmed in the field, the program must reside in Random Access Memory (RAM). RAM is susceptible to alteration and is recommended for limited use. Where RAM is used in a high safety integrity computer system, the system must have two-channels, and each channel must assure it performs RAM checks to ensure bit corruption has not occurred. In addition, the ability to program software in a structured high safety integrity manner is not what one could reasonably assume would be found in the workplace.
Traditional safety devices were constructed by interfacing discreet safety-related parts to a machine controller. The user settings were a programmed-in function by the user. As discussed above, this method fails to ensure high safety integrity.
Therefore, what is needed is a system that measures each device's response time in relation to the start of the event (the beginning of a new scan cycle of the detection device following a scan that detected no hand or other interruption in the hazard or sensing field). By measuring the elapsed time of each component in the chain of events from the start of the scan cycle, each component's response time can be validated and the accumulation of slow response times monitored.
What is also needed is an intelligent light curtain system that can "learn" its environmental surroundings and setup parameters (i.e. its own signal strength) and can adjust itself as necessary. In addition, what is needed is for the intelligent system to recognize its own light source and distinguish it from other spurious bursts of radiation. What is further needed is for the system to not allow its detection device to go into saturation. Still further, what is needed is that the safety integrity of the learning process be maintained throughout the system.
In order to overcome the response time monitoring problem of accumulation error, what is needed is a homogeneous system that incorporates the light curtain function and the safety-related control function, whereby the output response time of each device in the stop chain of command is clocked from the last unblocked scan of the light curtain. Further, the monitoring must be performed within milliseconds of when the device was to change state in order to provide a secondary method of machine stoppage in the event of failure to respond. To overcome problems associated with common failures of similar devices, an additional, dissimilar switching device in an unrelated current path is required.
For high integrity safety-related control systems, it is not enough to simply ensure that it produced an output. What is needed in this safety system is to ensure that the proper output is realized. The safety-related control system must monitor for the safe state of the machine. If that state is not realized within a specified time of response, the safety-related control system must be able to produce a secondary output to protect the operator. Each element in the stop chain of command must be monitored for its timely change of state in relationship to the last unblocked scan of the light curtain system.
Prior stop performance monitors are flawed in the fact that they do not take into account all of the events in the stop chain of command. SPMs disregard all interposing devices which may respond sluggishly such as the light curtain, the OSSD, the FSDs, the MPCEs, etc. SPMs do not monitor the true stopping time of the machine as it relates to safety of the operator reaching through the light curtain's sensing field into a hazardous machine area. These SPMs are also limited to monitoring only one type of machine (i.e. clutch/brake type). What is needed is a means to determine machine motion and to equate the amount of elapsed time from blockage of the light curtain to the cessation of motion.
What is needed is a homogeneous safety control system with two-channel structure and dynamic signal processing. The system must know when the muted condition is to occur and recognize fault conditions in the process. The system must also detect any misapplication or physical alteration of the position sensors. The system must inform the operator of a muted condition, must not bypass necessary safety mechanisms, and must maintain stop control in the event of a malfunction. The system must also verify that the mute signals are functioning properly prior to allowing the mute condition to occur. All of this must be done without compromising operator safety.
What is needed is a safety start actuator that requires a deliberate act by the operator to enable the machine to be put in motion. After power restoration, the actuator must create a lock-out upon power interruption. The actuator must be an integral part of the SRCS and must be monitored to ensure that a failed "on" state cannot exist. In addition, the actuator, or another actuator, must perform a restart enable function. What is further needed is an indicator to inform the operator of the reason for the machine stoppage.
What is also required for high safety integrity are means to initiate machine motion in a safe manner and ensure that machine motion cannot occur until the hazard zone is vacated of personnel. Although the prior art is satisfactory for some applications, it does not satisfy the requirements for high safety integrity needs. What is needed is a two-channel technique with comparison and dynamic monitoring. The two-channel technique must include two signals from each actuator (i.e. 4 signals which are processed by two independent signal processors and compared). Each signal processor must independently control a machine motion initiation device. All switch contacts must be monitored dynamically for their off/on/off states, and signal processors must compare the results. Systematic failure must result in a lockout state which is only recoverable by qualified personnel.
Since the two-hand control must be kept depressed for the entire downstroke of the press, a safety means must be incorporated to ensure that the two-hand control "knows" the position of the press' ram. A single-channel means could fail in the "closed position" and could falsely indicate a ram at the bottom state. Even two such devices could produce a dangerous condition by one device failing in such a state and then the other at some future time. What is needed is for the ram-position devices to be two-channel with a comparison check and verified on a dynamic basis. There is a need to know when the ram is at the top of its stroke to validate the initialization of the next stroke, and such validation must correspond with predetermined time parameters. In addition, what is needed is that the position sensors be validated for their ability to change state prior to relying on them to determine the location of the ram without jeopardizing operator safety.
The SRCS must verify that its motion initiation devices are operating properly. Failure of the two-hand control's actuators, restart enable actuators, start enable actuators, output devices, control, etc., and/or failure of the position sensors, and/or the interfacing control (i.e. machine control) must be detected by a homogenous safety system and must result in a lockout condition. When any one of these failures is detected, all safety device outputs must go to the "off" state to stop the machine motion. It is insufficient for high integrity safety systems to merely have the two-hand control's output remain "off" especially when it is a single-channel output.
What is needed is to incorporate all the system components (i.e. light curtain components, machine feedbacks, position sensors, machine initiation devices, mute operations) into a single homogenous SRCS. The SRCS must have two-channel structure with comparison, high-level safety integrity software, and must monitor interfacing elements for their respective states and response times as pertaining to the light curtain scan.
What is needed is a single homogenous SRCS with field-selectable modes of operation that require no field software programming to perform their desired functional manner of man/machine interface. What is further needed is an SRCS of two-channel structure with comparison and dynamic monitoring capabilities, programmed-implementing structure software, and a self-test of that software.
Finally, what is needed is a homogenous SRCS that requires no user program, but has user-selectable means that are automatically verified and tested by the SRCS after originally having been validated by the installer subsequent to proper selection at commissioning.

Continous real time safety-related control system


A method includes generating emitted signals using transmitter elements and measuring received signals using receiver elements. The received signals are reflected portions of the emitted signals and the received signals correspond to one or more targets. The method also includes applying a first matched filter to the received signals to determine range information for the received signals, filtering the received signals based on the range information to define filtered signals, and determining calibration parameters using the filtered signals. The method also includes correcting the received signals using the calibration parameters to define calibrated signals and determining angle of arrival information for the received signals using the calibrated signals.

Multi-channel time-of-flight imaging systems can provide estimates of range, velocity, and/or angle of arrival for reflecting targets that are located in their field of view. These types of systems are highly sensitive to minor variations, which may be static (e.g., manufacturing related) or may be dynamic (e.g., temperature related). These variations can result in gain and phase mismatch errors between channels, which can reduce the effectiveness of the imaging system.

Calibration for multi-channel imaging systems


Methods and apparatus for implementing a robust unicast/broadcast/multicast protocol are provided. In one aspect, a method of avoiding collision of intra-basic service set unicast, broadcast or multicast transmissions notifies stations in the basic service set of a reserved transmit opportunity for a unicast, broadcast or multicast transmission. Transmissions from at least one station in the basic service set are deferred until after the reserved unicast, broadcast or multicast transmit opportunity.

1. Technical Field
This disclosure generally relates to the field of transmission of audio and video streams in wireless local area network (WLAN) communications and, more particularly, to quality of service for multicast and broadcast of audio/video streams in WLAN communications.
2. Description of the Related Art
In recent years, wireless computer networks such as WLANs have been widely deployed in places ranging from homes and businesses to hotels, airports, schools, etc. Compared to wire networks, a WLAN provides users mobile connectivity and are typically more scalable and require lower cost in network construction. With the popularity of multimedia applications like streaming multimedia and voice over IP on the rise, it is important to ensure quality of service in the delivery of time-sensitive multimedia content in a WLAN.
Within the IEEE 802.11 WLAN standards, two access protocols at the MAC layer are defined: the mandatory distributed coordination function (DCF) and the optional point coordination function (PCF). The DCF protocol uses a carrier sense multiple access with collision avoidance (CSMA/CA) method to decide which station in the WLAN should send packets out. The WLAN stations listen to the wireless medium to determine when it is free, or idle. Once a station detects that the medium is idle, the station begins to decrement its back-off counter. Each station maintains a contention window (CW) that is used to determine the number of slot times a station has to wait before transmission. The back-off counter only begins to decrement after the medium has been idle for a DCF inter-frame space (DIFS) period. If the back-off counter expires and the medium is still idle, the station begins to transmit. Thus, it is possible that two stations may begin to transmit at the same time, in which case a collision occurs. If a frame is successfully received by the destination the frame is addressed to, the destination sends an acknowledgement (ACK) frame to notify the source of the successful reception. However, as there is no centralized coordination in DCF, a relatively high number of collisions still occur especially in a WLAN with high load.
In an infrastructure basic service set (BSS) with a WLAN, typically including an access point (AP) and associated non-AP stations (STAB), centralized coordination can be achieved when using the PCF protocol as PCF requires the AP to poll the stations to coordinate access to the wireless medium. However, PCF is rarely implemented as the implementation is complicated because AP has to poll the non-AP stations for the transmission of each polled packet. Additionally, it is difficult to integrate an effective power saving mode with the PCF protocol.
The IEEE 802.11e is an approved amendment that defines a set of quality of service enhancements for WLAN applications through modification to the media access control (MAC) layer. Specifically, the IEEE 802.11e enhances the DCF and PCF protocols through the hybrid coordination function (HCF). The HCF includes two protocols of channel access: enhanced distributed channel access (EDCA) and HCF controlled channel access (HCCA). As the HCCA protocol uses contention free periods to transmit data streams, it makes efficient use of the bandwidth. However, implementation of the HCCA protocol tends to require a relatively complex scheduler and added complexity. With the EDCA protocol, data streams are assigned different priorities and thus high-priority data streams have a higher chance of being transmitted than low-priority data streams. Each priority level is assigned a respective Transmit Opportunity (TXOP), which is a time interval during which a station in a BSS can transmit as many frames as possible.
Video streams require reliable transmission and deterministic delay. At current time it is difficult, however, to provide reliable video transmission in an IEEE 802.11-based WLAN because of insufficient support of broadcast and multicast transmissions. For example, an intra-BSS collision occurs if associated stations transmit frames when the AP is transmitting broadcast/multicast frames. When two or more BSS's overlap each other, an overlapping BSS (OBSS) or inter-BSS collision might occur. The collision may happen, for example, if a station or the AP of a first BSS transmits frames when an AP of a second BSS that overlaps the first BSS is transmitting broadcast/multicast frames. Furthermore, there is no feedback mechanism to indicate the correct reception of the broadcast/multicast frames transmitted by the AP.
In addition, the EDCA protocol currently does not provide deterministic delay guarantee. Although there are efforts made to include a reservation-based medium access method in the IEEE 802.11n and 802.11s drafts, a number of issues still need to be addressed in order to provide reliable reserved medium access for transmission of video streams. For example, issues related to coexistence with legacy OBSS and coexistence with or without OBSS should be considered.

Robust unicast/broadcast/multicast communication protocol


A method for wirelessly transmitting data to a control unit, such as a blasting machine, selected from a plurality of control units from an operating device selected from a plurality of operating devices, and a system intended for the method. The control unit is connected to a plurality of detonators, which are controlled by the control unit via an electrical wire or a fuse. The operating device is associated with the appropriate control unit in a step in which address data and/or encryption data is exchanged between the units. Only one operating device can be associated with a pre-determined control unit at any given moment. The data transmitted in accordance with the method preferably comprises at least a fire command, which instructs the control unit to fire the detonators.

A detonator is usually used to cause detonation of a large explosive charge, even though detonators themselves, in some cases, can be used as charges. In blasting operations, bores are drilled in which explosives are applied to create a charge. A detonator is arranged in or adjacent to the explosive, which is set off by the intermediary of the detonator.
In large blasting operations, it is often desirable to create a carefully calculated delay of the detonation of the detonators for the purpose of obtaining a desired blasting sequence. The delay is achieved in various ways depending on the type of detonator being used. A detonator may, for instance, be pyrotechnic or electronic. In pyrotechnic detonators, the desired detonation delay is achieved by means of delay charges, which have a preset burning time. In electronic detonators, the desired delay is usually achieved by means of electronic circuits, which count down a programmed delay time and then feed a current to an electric fuse head, which causes the detonator to detonate.
In many cases, it is desirable to be able to walk around the blast site for inspection and monitoring purposes before firing. Furthermore, it may be desirable to be able to initiate firing from any optional site remote from the blast site.
One problem associated with detonator systems according to prior art is that the operator has to initiate firing from a site adjacent to the blast site to be able to physically press the arming and firing buttons of a blasting machine. To set off the detonators, the blasting machine is connected thereto by means of, for example, a fuse or electrical wires. Wireless firing would allow a more flexible system.
Wireless firing of detonators is disclosed, for instance, in U.S. Pat. No. 5,159,149. The purpose of the detonator system described therein is to get round the use of any physical connection between the detonators in a round. According to the description, this purpose is achieved by providing each detonator of the round with a receiver for receiving a fire command signal from a transmitter. When preparing a blast, a transportable charging and programming unit is carried round the blast site, said unit being connected to the respective detonators for charging electric fuse means and for programming the desired delay times in the detonators.
However, the detonator system of the above patent specification has a number of serious limitations and drawbacks. Although the physical interconnection of detonators by means of a fuse or electrical wires has been eliminated, a charging unit that has to be carried round the blast site is required. It is evident that this will complicate the work to be carried out. A further drawback of such a method is that the state of the detonators cannot be checked when the programming unit is disconnected. Consequently, it is not possible to ensure, at a later stage, that the detonators are charged and that they will in fact detonate when receiving a fire command.
Moreover, a system according to the above patent specification is associated with considerable risks. In reality, the person preparing the charges at the blast site will be surrounded by armed detonators, which will detonate upon receipt of a fire command. Any radio frequency interference in the receiver of a detonator, or any inadvertent transmission of a fire command from the transmitter, would therefore have devastating consequences. It is even conceivable that another radio signal source not associated with the detonator system transmits, intentionally or by mistake, a radio signal that is interpreted as a firing signal by the receiver.
Furthermore, each individual detonator has to be provided with a receiver. Considering the fact that a round may comprise a considerable number of detonators, this may imply a significant increase in system costs.
Another general problem associated with wireless firing of detonators is that it is necessary to somehow ensure that only the intended round can be fired. For example, a plurality of rounds may be arranged within a limited area (within one radio coverage area), but it may be desirable to fire only one of these rounds. The obvious problem then is how to make sure that only the intended round is fired.
Accordingly, there is a demand for improved detonator systems that eliminate the risks and problems mentioned above.

Detonator system and method in connection with the same


A non-computer interface to a storage system includes a set top box (STB) or interface unit connected to a storage system for storing information to be accessed by a user. The storage system can be a database, such as a relational database having a plurality of tables, or a digital library system, for storing information to be accessed by the user. Also stored in the storage system are navigation information or rules for controlling a user""s navigation of the database. A user interacts with the storage system through the STB, sending navigation commands to the storage system via the STB. The navigation commands available to a user are generated by combining the navigation rules with the user""s access privileges. The user can send navigation commands via a remote controller which sends cursor control commands to the STB. Alternatively, the user can send navigation commands via a virtual reality interface.

1. Field of the Invention
The present invention relates to information processing systems, and more specifically to storage management systems and interfaces to such storage management systems.
2. Description of the Related Art
Conventional storage systems employ a database management system (dbms) for storing information in a database and for searching for and retrieving that stored information. Databases can be either hierarchical or relational, with relational databases often storing information in a plurality of database tables. Dbms""s generally provide mechanisms for a user to interact with the database. For example, a database view is a static definition of specific portions of the database is that are made visible to a user. For example, in a relational database having many tables, each of which is comprised of a plurality of rows and columns, a view of that database may be a predefined, static definition of only certain columns of certain tables of the database. Accordingly, when using that view of the database a user would only be given access to, or xe2x80x9cseexe2x80x9d, the portions of the database defined in a view. In order to view the database a user would have to execute a database query that returns results based on a specified view. Both constructing the database query and interpreting the results of the query returned according to the view can often be complicated and can be difficult tasks to be performed by users unfamiliar with database interfaces.
Another information storage system is a digital library as described in U.S. Pat. No. 5,649,185 to Antognini et al., which is incorporated herein by reference. A digital library uses a database, file systems and other storage mechanisms, but also allows application programs, residing on a library client, to interact with the underlying digital library services and hence the underlying database, to store and retrieve information. However, the digital library application programs also require a computer end-user interface, requiring a user to use a computer monitor, keyboard and/or mouse to interact with the application program. Furthermore, the application programs require predetermined queries and views to locate and access data within the digital library. However, those predetermined queries and views often do not take advantage of the structure of the data stored within the database.
Potential database and digital library users in many industries and educational establishments desire avoiding computer interfaces for their applications, such as viewing rough video cuts and video production dailies as well as still images from graphics and art departments. To facilitate this access, yet modernize their applications to allow digital storage and distribution, users untrained in the computer arts need methods to access information different from conventional computer interface methods.
The simplest, most commonly accepted interface outside of the computer industry is that of a television with a remote controller, with the remote controller capable of entering numeric data, numerically selecting from simple menus, and simple navigational controls. If properly integrated and supported within a database, either (relational or hierarchial), or a digital library system, a VCR-like menu interface can provide sufficient function to implement most of the object search, selection, and viewing applications required by this user subset.
A product called xe2x80x9cWEB TVxe2x80x9d has been introduced which employs a set top box (STB) and a remote controller to control a conventional television set to display so called xe2x80x9cweb pagesxe2x80x9d of Internet xe2x80x9cWorld Wide Webxe2x80x9d (WWW) sites. The STB provides an interface to the WWW and controls the television set to display web pages and control menus. The STB also responds to commands received from the remote control in order to navigate the WWW. Typically the remote controller transmits an infrared (IR) signal to the STB. However, the WEB TV system provides only a limited function of navigating the WWW, and does not provide access to other information that may be stored in databases or digital library systems not accessible by the WWW.
To enable digital library and database installation, acceptance, and replication, it is important to offer a very simple non-computer interface that provides a reasonable level of function, but still maintains full access, security and control over the users"" data.
An object of the invention is to provide an interface to a database or a digital library system that is more intuitive to users untrained in the computer arts than using a conventional computer interface.
Another object of the invention is to provide a database or digital library system that can be navigated dynamically based on its structure and a user""s access privileges.
An important aspect of the invention involves providing context sensitive navigational methods, which are made possible by embedding the necessary control information, or in other words xe2x80x98roadmapxe2x80x99 information, into the database or data hierarchy. This xe2x80x98roadmapxe2x80x99 information, combined with user specific access and control information is used as input into a rule-based logic system that generates dynamic navigational commands for controlling the database or digital library.
To achieve the objects of the invention there is provided an apparatus providing an interface for browsing a storage unit, including a control unit for generating and transmitting a selection signal and an interface unit for connection to the storage unit. The interface unit receives a signal from the storage unit indicating a plurality of selection items and presents the selection items. Then, the control unit generates the selection signal to select one of the plurality of presented selection items, and the interface unit receives the selection signal and transmits a to signal for controlling the storage unit to access an area of the storage unit indicated by the selection signal. The control unit includes a remote controller having one or more controls for selecting one of the presented selections. The remote controller includes directional keys for controlling movement of a cursor displayed on the display monitor, wherein the cursor position changes on the display monitor in response to operation of the directional keys; and a selection key for indicating selection of one of the presented selections items displayed closest to the location of the cursor.
To also achieve the objects of the invention, there is provided a method of controlling a storage unit, including presenting first navigation information from a first portion of the storage unit; sending a navigation command to the storage unit conforming to the presented first navigation information to access a second portion of the storage unit; and receiving second navigation information from the storage unit. The first and second navigation information are based on the first and second accessed portions of the storage unit, respectively, and an access privilege of a user. The method further includes transmitting information regarding the user requesting access to the storage unit prior to presenting the first navigation information, wherein the received first navigation information includes only navigation information resulting from comparing the transmitted user information with an object embedded in the storage unit, the embedded object containing the first navigation information. The sending of the navigation command is based on selection of a directional control, the directional control indicating a direction of navigating the storage unit, wherein the storage unit can be either a database or digital library.
The invention is still further directed to a computer program product including computer readable program code for performing the method discussed above.

Non-computer interface to a database and digital library

International Business Machines Corporation


The present invention provides a voltage regulator capable of causing a large output current to flow during a heavy load operation, and of making a leakage current from output transistors small during a light load operation. The voltage regulator includes a plurality of output transistors and a circuit for changing connection of the output transistors to allow a W/L value of the output transistor to be changed. Moreover, the voltage regulator further includes an output current detection circuit for detecting an output current, and a circuit for changing connection of the output transistors based on the output current to allow a W/L value of the output transistors to be changed based on the output current.

1. Field of the Invention
The present invention relates in general to a voltage regulator, and more particularly to a voltage regulator capable of decreasing a leakage current from output transistors when a load is light.
2. Description of the Related Art
As shown in FIG. 3, a conventional voltage regulator includes a voltage regulator control circuit having a reference voltage circuit 2, bleeder resistors 6 and 7 for voltage-dividing an output voltage Vout appearing at an output terminal 5 of the voltage regulator, and an error amplifier 3 for amplifying a voltage difference between a reference voltage Vref from the reference voltage circuit 2 and a voltage Va appearing at a node between the bleeder resistors 6 and 7, and an output transistor 4. The voltage regulator operates at a power supply voltage VDD supplied from a voltage source 1.
When an output voltage of the error amplifier 3 is assigned Verr, if the voltage Va is larger than the reference voltage Vref, the output voltage Verr becomes higher, while if the voltage Va is smaller than the reference voltage Vref, the output voltage Verr becomes lower. When the output voltage Verr of the error amplifier 3 becomes higher, the output transistor 4 becomes larger with its ON resistance to serve to decrease the output voltage Vout. On the other hand, when the output voltage Verr of the error amplifier 3 becomes lower, the output transistor 4 becomes smaller with its ON resistance to serve to increase the output voltage Vout. The voltage regulator control circuit holds the output voltage Vout constant by those mechanisms.
Since resistance values of the bleeder resistors 6 and 7 are generally set to very large values, the voltage regulator controls the output transistor 4 so that the ON resistance of the output transistor 4 becomes very large when a load is light (e.g., refer to JP 07-74976 B (FIG. 2)).
However, if the output transistor 4 is so controlled that its ON resistance becomes very large when the load is light, there is encountered a problem in that an influence of a leakage current from the output transistor 4 becomes larger and hence the output voltage Vout cannot be held constant. In general, when a channel width and a channel length of a transistor are assigned W and L, respectively, a W/L value is reduced to allow a leakage current from the transistor to be reduced. In this case, however, an amount of current which can be caused to flow when a load is heavy becomes lesser accordingly.


A loader for a conveyorized cooking apparatus having a transverse partition spaced from an endless loading belt. The loader may include several longitudinal partitions defining a plurality of dispensing stations for loading hamburger patties and like food items. The transverse partition is spaced above the endless loading belt by a distance slightly greater than the typical thickness of a patty to be cooked. The endless loading belt has at least one transverse outwardly extending cleat. As the loading belt travels, the outwardly extending cleat comes into contact with the lowermost patty of each stack of patties on the loading belt and pushes the lowermost patty through the space between the transverse partition and the endless loading belt and into the cooking apparatus. A conveyorized cooking apparatus and a method of loading food patties into a conveyorized cooking apparatus are also disclosed.

1. Technical Field
The present invention relates generally to the field of conveyorized food cooking apparatus and more particularly to an apparatus for automatically loading food patties such as hamburgers, xe2x80x9cveggie burgers,xe2x80x9d beef steaks, fish filets, and chicken filets into a conveyorized cooking apparatus.
2. Background Information
Commercial restaurants, particularly those restaurants commonly referred to as xe2x80x9cfast food restaurantsxe2x80x9d that typically specialize in serving hamburgers and like sandwiches, are continually striving to reduce operating costs while at the same time increasing food cooking production and efficiency. Toward this end, many such restaurants have begun in recent years to utilize conveyorized cooking apparatus by which cooking times and temperatures can be better regulated than by more traditional cooking methods while at the same time eliminating or at least reducing the need for skilled labor.
A typical conveyorized cooking apparatus includes an endless cooking conveyor, which is often made from a metal mesh or metal rod xe2x80x9cbelt,xe2x80x9d having a horizontal run through a cooking chamber equipped with burners or heating elements on each side of the cooking conveyor. To use such an apparatus, workers manually separate the individual food patties, which are usually stored in a frozen patty stack, and then place several of the individual patties directly on the endless cooking conveyor. The patties then travel between burner elements where they are cooked and emerge from the cooking apparatus to be placed in a sandwich and sold.
While conveyorized cooking apparatus increase the food cooking production of fast food restaurants, manual loading of such apparatus creates many problems. Since individual food patties are placed directly on the actual cooking conveyor, there is a danger that employees may bum their hands by inadvertently touching the cooking conveyor while placing the patties. Since the cooking chamber is accessible, there is a danger that employees may push patties too far into the cooking apparatus when loading, which may result in undercooking the patties because they have not traveled completely through the cooking apparatus. Since there are no predetermined loading positions, manual loading may result in less than optimal cooking production if less patties are loaded on the cooking conveyor than the conveyor can accommodate or in incomplete cooking if too many patties are loaded on the conveyor and adjacent patties are overlapping. Finally, manual loading requires employees to make frequent trips to load the conveyorized cooking apparatus during peak demand times, rendering those employees unavailable for other tasks. If employees become preoccupied with other tasks and forget to make enough frequent trips to load the conveyorized cooking apparatus, then an insufficient supply of cooked food patties during large customer demand periods may result.
There have been several attempts to address the problems associated with manual loading of conveyorized cooking apparatus. U.S. Pat. No. 4,151,930 to Baker et al. discloses an automatic patty feeder using a solenoid and pusher mechanism to force the lowermost patty in a stack of patties onto a cooking chain. U.S. Pat. No. 4,182,231 to Baker et al. discloses a frozen patty feeder disposed partially over a cooking conveyor and having a transversely extending first wall and an inclined transversely extending second wall supported by a pair of side walls. A stack of staggered frozen patties are placed in the feeder and a combination of friction and interengagement urges the lowermost patty onto the cooking conveyor. U.S. Pat. No. 4,254,697 to Lang-Ree et al. discloses a broiler with a patty feed that also relies upon friction and partial interengagement to move the lowermost patty directly onto the cooking conveyor. U.S. Pat. No. 5,127,544 to Robinson et al. discloses an automatic sandwich preparation system in which a plurality of frozen hamburger stacks may be loaded into canisters. A reciprocating ejection slide is used to push the lowermost patty of a particular stack onto the cooking conveyor.
While these attempts to automate the loading process of a conveyorized cooking apparatus may have some advantages, they also have several significant disadvantages. Feeders having a plurality of moving cylinders or relying upon solenoid-activated mechanical linkages may severely disrupt food preparation capability should any of the associated loader parts fail. Moreover, use of such relatively complicated loader mechanisms conflicts with an overriding principle in the fast food industry that operating machinery must be kept as simple as possible, given the need for maximum food production, the heat and grease filled environment, and the relatively unsophisticated nature of the typical worker in the industry.
Feeder devices that rely on direct interengagement of the cooking conveyor with the lowermost patty can also be disadvantageous. If the lowermost patty is solidly frozen to the patty above, the cooking conveyor would continue to grind against the bottom of the lowermost patty. Moreover, such direct interengagement would be less successful for cooking thawed hamburger patties and patties such as fish filets that might tear more easily than frozen hamburger patties.
Feeder devices that do not adequately shield the feeder surfaces from the heat generated by the associated cooking apparatus increase the likelihood that the relatively cool patties will stick to the hot feeder surfaces. This is disadvantageous for two reasons. First, when patties stick to the feeder surfaces they will often fail to load properly into the cooking apparatus. Second, portions of the patties that stick to the hot feeder surfaces essentially bake onto those surfaces making clean up and sanitation of the feeder devices difficult.
Thus, it would be desirable to have in the art an automatic loader for a conveyorized cooking apparatus that is simple in construction and simple to operate. Ideally, such an improved loader would allow maximum utilization of the cooking chamber and ensure that all food items travel completely and consistently through the conveyorized cooking apparatus. Such an improved loader should sufficiently shield loader surfaces from heat generated by the associated cooking apparatus to minimize the possibility of patties sticking to hot loader surfaces and should be easy to adequately clean and sanitize. Finally, such an improved loader should be easily adaptable to existing conveyorized cooking apparatus and have a large food loading capability.
The present invention overcomes the disadvantages and drawbacks associated with conventional patty feed apparatus by providing a loader for a conveyorized cooking apparatus having a transverse partition and an endless loading belt. The loader may include several longitudinal partitions to thereby define a plurality of dispensing stations for hamburger patties, veggie burger patties, chicken filets, fish filets, or the like (these and other generally flat and essentially stackable food items being referred to herein collectively as a xe2x80x9cpattyxe2x80x9d or xe2x80x9cpattiesxe2x80x9d). The transverse partition is spaced above the endless loading belt by a distance slightly greater than the typical thickness of a patty to be cooked.
At least one outwardly extending cleat is provided to push the lowermost patty of a stack of patties between the loading belt and the transverse partition into the cooking apparatus. The endless loading belt can be driven, i.e., made to travel, by the same mechanism that powers the cooking conveyor. For example, a spur gear coupled on one roller supporting the endless loading belt may be coupled to a spur gear on one axle shaft supporting the cooking conveyor by use of an idler spur gear. In this way, the endless loading belt may travel at the same speed as the cooking conveyor when the cooking conveyor is driven. Alternatively, independent means such as a motor, chain, and sprocket wheel mechanism may be used to power the endless loading belt.
Stacks of patties such as frozen hamburgers, veggie burgers or other food products desired to be cooked are placed on the traveling endless loading belt, preferably immediately behind one of the outwardly extending cleats, and in positions corresponding to the dispensing station or stations defined by the dispensing partition unit. As the next outwardly extending cleat comes into contact with the lowermost patty of each stack of patties, the lowermost patties are pushed forward by the cleat through the space between the partition unit and the endless loading belt and onto the cooking conveyor. Other patties in the patty stacks, i.e., those patties that are not the lowermost patties, are prevented from going forward into the conveyorized cooking apparatus by the transverse partition. A sheet of TEFLON or other xe2x80x9cnon-stickxe2x80x9d material may be positioned between the stacks of patties and the transverse partition of the dispensing partition unit to prevent the patties from sticking to the transverse partition.
In this manner, an employee in a fast food restaurant can quickly load a large amount of patties to be cooked into a conveyorized cooking apparatus by merely placing stacks of these patties on the endless loading belt at the dispensing station or stations. The employee is then free to perform other tasks and the present invention ensures that all such patties are automatically loaded sequentially and at spaced intervals into the conveyorized cooking apparatus. Advantageously, predefined dispensing stations may be used to ensure that each hamburger, filet piece or other patty is placed on the cooking conveyor at the same location and the plurality of equally spaced outwardly extending cleats on the endless loading belt creates a uniform space between successive patties as they travel through the cooking chamber. Thus, utilization of cooking chamber area is maximized and catching members may be correspondingly positioned at the discharge of the conveyorized cooking apparatus to collect the cooked pieces. Uniform cooking of the patties is achieved and the risk of undercooking patties is minimized because the loader ensures that each patty travels completely through the cooking apparatus. These and other advantages of the present invention will become apparent upon reading the following detailed description and appended claims, and upon reference to the accompanying drawings.

Loader for conveyorized cooking apparatus