An organ assist system having a closed fluid system having a ring-shaped prosthetic contactively surrounding at least a portion of a body part, including bladders adapted for selectable dilation and contraction in response to varying fluid pressure therewithin, a fluid pump, and apparatus for pressurizing the bladders; and a control unit for controlling operation of at least the fluid pump; pressure sensors within the fluid system; a power source, and shut off valves. The pressurization apparatus includes pressure cells arranged in an array, each pressure cell having a shut-off valve at its inlet, and a shut-off valve at its outlet, the shut-off valves being controlled by the control unit such that the pressurization apparatus is operable to provide a range of pressurizations to the bladders of the prosthetic for applying a controlled variable pressurizing effect to the body part thereby.

In recent years, there have been many developments in the field of cardiac assistance, with a plethora of devices and systems for aiding the pumping of a dysfunctional heart. One common approach is to use a pacemaker that provides an electrical pulse that causes the heart to dilate. Another approach is to perform a heart transplant, replacing the heart with a donor heart. A further approach is to use an artificial heart. Artificial hearts are particularly useful as short term, bridging solutions until appropriate donor hearts are available.
A third approach is to provide a heart assist device, essentially a prosthetic that is wrapped around the heart, or a part thereof, such as to the left ventricle, for example. Contraction of the prosthetic provides a squeezing force on the heart helping it to pump.
A variety of mechanical cardiac devices have been developed, including pumps that serve as ventricular assist devices and full artificial hearts. Each device performs differently and is appropriate for a different specific function.
In 1969, the world's first total artificial heart implant was performed by Dr. Denton A. Cooley. The device, developed by Dr. Domingo Liotta, was implanted in a 47-year-old patient with severe heart failure, and supported the patient for nearly three days, until a donor heart was found allowing transplantation. The Liotta total artificial heart was an air-driven (pneumatic), double-ventricle pump. Wada-Cutter hingeless valves controlled the flow of blood through the inflow and outflow areas of the pump. The two pump chambers (the "ventricles"), the cuff-shaped inflow tracts (the "atria"), and the outflow tracts were lined with a special fabric that promoted the formation of a smooth cellular surface. The flexible inflow and outflow tracts were made of Dacron fabric, and the pump chambers were made of Dacron fabric and Silastic plastic. The pumps were connected to the external power unit with Silastic tubing covered by Dacron fabric. The console, also a major engineering accomplishment at the time, was about the size of a large household washing machine. Two pneumatic power units generated the pumping and vacuum actions needed to move blood through the artificial heart. The complex control panel included numerous switches and knobs used to adjust pumping rate and pumping pressure.
In July 1981, Dr. Cooley again implanted a total artificial heart. Developed by Dr. Tetsuzo Akutsu at the Texas Heart Institute, the Akutsu III total artificial heart was implanted in a 36-year-old man, keeping him alive for 55 hours, until a donor heart was found for transplantation. The Akutsu III total artificial heart contained two air-powered, double-chambered pumps. The pumping chambers were made of a smooth material called Avcothane, which could be molded in one piece. The inflow and outflow ports contained Bjork-Shiley disc valves. The prosthetic ventricles were attached to the remnants of the natural heart's atria and to the great vessels by flexible inflow and outflow conduits with detachable quick-connectors. The pumps were connected with Dacron velour-covered tubing to an external control console. The control console had three basic systems: a pneumatic (air-driven) drive system, an electrical monitoring/control system, and an electrical power system. The pneumatic drive system provided both pressure and vacuum to each ventricle. Under normal use, the console was connected to wall pressure and vacuum sources. During patient transport, or in the event of in-house power failure, the system automatically switched to on-board compressed air tanks. Monitoring of heart rate and systolic duration were the primary functions of the electrical monitoring/control system. The monitoring/control system provided a digital readout of driveline pressure and vacuum supplied, as well as the status of standard and emergency power supplies. The electrical power system had two independent sources of power: standard AC/DC power and a back-up battery in case of power failure.
The Jarvik-7 total artificial heart, designed by Dr. Robert Jarvik is probably the best known of the artificial heart devices. It is designed to function like the natural heart. It was first implanted in a patient named Barney Clark in 1982, who survived for 112 days. By the late 1980s, surgeons had used the Jarvik-7 as a bridge to transplantation in more than 70 patients. Subsequently, the Jarvik-7 was called the Symbion total artificial heart. Today, it is known as the CardioWest total artificial heart and is still in use as a bridge to transplantation.
The Jarvik-7 has two pumps, much like the heart's ventricles. Each sphere-shaped polyurethane "ventricle" has a disk-shaped mechanism that pushes the blood from the inlet valve to the outlet valve. The ventricles are pneumatically (air) powered. Air is pulsed through the ventricular air chambers at rates of 40 to 120 beats per minute. The artificial heart is attached to the heart's natural atria by cuffs made of Dacron felt. The drivelines out of the ventricular air chambers are made of reinforced polyurethane tubing. Where they exit the skin, the lines are covered with velour-covered Silastic which ensures stability and encourages tissue growth even with movement by the patient. The air-driven, external power system powers the pump through drivelines that enter the heart through the patient's left side. The large console on wheels is as large and as heavy as a household refrigerator. It is normally connected to sources of compressed air, vacuum, and electricity. The system is backed up by a rechargeable battery in case of power failure and includes on-board compressed air tanks (modified scuba type) for use during patient transport. Controls in the console allow the doctor to control pump rate, pumping pressure, and other essential functions.
The AbioCor™ implantable replacement heart represents the culmination of 30 years of research, development, and testing conducted by ABIOMED, Inc. and its collaborators, with the support of the National Heart, Lung and Blood Institute. It was the first completely self-contained total artificial heart and is designed to sustain the body's circulatory system and to extend the lives of patients who would otherwise die of heart failure. Unlike other systems described hereinabove, it is totally implanted within the body, and patients are not tethered to a large, air-pumping console nor do they have wires or tubes piercing their skin. The AbioCor is intended for use in end-stage heart failure patients whose hearts have irreversible left and right ventricular failure and for whom surgery or medical therapy is inadequate.
The AbioCor consists of a thoracic unit, an internal rechargeable battery, an electronics package and external console. The thoracic unit (the pump) weighs around a kilogram and consists of the artificial ventricles, which contain their corresponding valves, and a motor-driven hydraulic pumping system. The hydraulic pumping system uses pressure to shuttle blood from side to side, from the artificial right ventricle to the lungs or from the artificial left ventricle to the rest of the body. To create this pressure, the pump's motor rotates at 4000 to 8000 revolutions per minute. The internal rechargeable battery is an emergency battery that is continually charged by the external power source. The internal battery can provide up to 20 minutes of operation while disconnected from the main battery pack. The electronics package is implanted in the patient's abdominal area and monitors and controls the pumping speed of the artificial heart. The AbioCor is normally powered by an external console or battery packs. The internal battery powers the pump only when the external power supply is disconnected. Power to the AbioCor is achieved with an energy-transfer device called a transcutaneous energy transmission (TET) system. The TET system consists of internal and external coils that are used to transmit power across the skin. Because tubes or wires do not pierce the skin, the chances of developing an infection are decreased. External battery packs can power the AbioCor for 4 hours.
The ABIOMED BVS-5000 is currently in use worldwide for temporary left, right, or biventricular (both ventricles) support in patients with potentially reversible heart failure. The BVS-5000 underwent preclinical studies at the Texas Heart Institute (THI) from 1986 to 1988 and was introduced for use in patients at THI in 1988. It was the first heart assist device approved by the U.S. Food and Drug Administration for the support of post-cardiotomy patients (those who have developed heart failure as a result of heart surgery). Since that time, hundreds of patients have been sustained by the BVS-5000. In addition to post-cardiotomy support, the BVS-5000 may also be used for donor heart dysfunction or donor heart failure after heart transplantation, right-sided heart failure after placement of a left ventricular assist device, after acute heart attack or acute heart disorders, such as viral myocarditis, after trauma to the heart, after disease of the heart muscle (cardiomyopathy).
In patients whose hearts have not recovered after temporary support, the BVS-5000 may be used as a bridge to another device or as a bridge to heart transplantation. The air-driven blood pump is placed outside the body (extra corporeally). A unique feature of the BVS-5000 system is its dual-chamber design, which is similar to the natural heart, and provides support for either the left or right ventricle, or both. The pump houses two polyurethane chambers: an atrial chamber that fills with blood through gravitational force and a ventricular chamber that pumps blood by air-driven power. The atrial chamber is vented outside the patient. The ventricular chamber is connected to the power console by a 0.25-inch pneumatic (air) line. Two trileaflet valves separate the atrial and ventricular chambers. The pump can produce blood flow of up to 5 liters per minute. Cannulas of various designs (for blood drainage and return) are available to accommodate different patient anatomy. The BVS-5000 console can support one or two blood pumps. It is fully automatic and compensates for changes both in preload and after load. The left and right sides are triggered independently of each other. A backup battery provides 1 hour of support, and an alarm sounds when only 10 minutes of power remain. A foot pump can also serve as a backup power source. By using the console to limit blood flow; patients can be slowly weaned from support.
A related device, the Abiomed AB5000 Circulatory Support System is a short-term mechanical circulatory support system that can provide left, right, or biventricular support for patients whose hearts have failed but have the potential for recovery. The AB5000 can be used to support the heart, giving it time to rest—and potentially recover native heart function. The device can also be used as a bridge to definitive therapy.
Since January 1986, when Dr. O. H. Frazier of the Texas Heart Institute initiated clinical trials thereof, the Thoratec HeartMate®IP LVAS is in use worldwide as a bridge to heart transplantation. It provides physical rehabilitation and greatly improves the clinical status of bridge-to-transplant patients. When patients are supported by the HeartMate for more than 30 days, the outcome of transplantation improves. The pneumatic (air-driven) LVAS pump is a titanium alloy pump that weighs 570 grams and consists of a blood chamber, an air chamber, a driveline, and inflow and outflow conduits. Each conduit is a titanium cage that contains a 25-mm porcine (pig) valve within a woven Dacron-fabric graft. A flexible polyurethane diaphragm separates the blood chamber and the air chamber. Textured surfaces within the blood chamber promote the development of a cellular lining, which helps prevent blood clots and infection. With a stroke volume of 83 milliliters and a maximum pumping rate of 140 beats per minute, the IP LVAS can provide flow rates of up to 12 liters per minute. The HeartMate console powers and controls the implanted IP LVAS blood pump. A 6-foot cable joins the blood pump to the drive console. Another 6-foot long tubing connects from the pump to the console to push air into the pump chamber. A front panel display gives a continuous readout of the pump rate, stroke volume, and total blood flow. The system can operate in three modes: automatic mode, fixed-rate mode, and external (synchronous) mode. The drive console is easy to operate and can be transported on a wheeled cart, allowing patients to move about the hospital.
The Thoratec Heartmate® XVE LVAS was developed and tested by Thermo Cardiosystems, Inc. and the Texas Heart Institute. In 1991, the system was implanted in a patient who was subsequently supported for 505 days and was able to leave the hospital while being supported by this device, paving the way for other patients to routinely wait at home for their transplants. Because the system is relatively easy to use, patients and their families can maintain it outside the hospital setting. Patients can live at home, return to work, and resume a more normal lifestyle while awaiting a suitable donor heart. Recently, the (FDA) approved the HeartMate XVE LVAS as permanent support for end-stage heart failure patients not eligible for heart transplants. The titanium blood pump thereof consists of a blood chamber, a motor chamber, a driveline, and inflow and outflow conduits. The pump weighs a mere 1150 grams. Each conduit contains a 25-mm porcine (pig) valve within a woven Dacron-fabric graft. A polyurethane diaphragm separates the blood chamber and the motor chamber. Textured surfaces within the blood chamber promote the development of a cellular lining, which help prevent blood clots and infection. The XVE LVAS has a maximum stroke volume of 83 milliliters and can be operated at up to 120 beats per minute, resulting in flow rates of up to 10 liters per minute.
The XVE LVAS's external equipment includes a system controller, a power base unit, and a 20-foot power cable, as well as batteries and other accessories. The system controller continuously monitors and controls the implanted motor and shows information regarding alarm conditions. The power base unit serves as a battery charger and as an interface between the system monitor and the implanted pump. The 20-foot power cable allows the system to be operated by AC power. Alternatively, patients can wear a portable battery pack around their waist, which permits the system to be operated tether-free for up to 8 hours.
A further development of the XVE LVAS, the Thoratec HeartMate® II LVAS was developed and tested by Thoratec Corporation, Inc., and the Texas Heart Institute (THI). The HeartMate II is being evaluated initially for use as a bridge to transplantation. Eventually, it is hoped that the HeartMate II can be used for destination therapy—as permanent support for end-stage heart failure patients who are not eligible for heart transplantation.
The HeartMate II is a high-speed, axial flow, rotary blood pump. As an axial flow device, the HeartMate II produces no pulsatile action. Weighing 12 ounces (about 375 grams) and measuring about 1.5 inches (4 cm) in diameter and 2.5 inches (6 cm) long, it is significantly smaller than other currently approved devices. As such, it may be suitable for a wider range of patients, including small adults and children. The internal pump surfaces are fabricated from smooth, polished titanium. Within the pump is a rotor that contains a magnet. The rotor assembly is rotated by the electromotive force generated by the motor. The rotor propels the blood from the inflow cannula out to the natural circulation. The pump speed can vary from 6,000 rpm to 15,000 rpm, providing blood flow of up to 10 liters per minute. The pump can run in two operating modes: fixed speed and auto-speed. In fixed-speed mode, the device operates at a constant speed, which can be adjusted via the system monitor. In the auto-speed mode, the pump speed varies in response to different levels of patient or cardiac activity. The HM II LVAS's external equipment includes a system driver, a power base unit, and a 20-foot power cable, as well as batteries and other accessories. The system driver continuously monitors and controls the implanted motor and shows information regarding alarm conditions. The power base unit serves as a battery charger and an interface between the system monitor and the implanted pump. The 20-foot power cable allows the system to be operated by AC power. Patients can wear a portable battery pack around their waist, which permits the system to be operated tether-free for three hours.
The Thoratec Ventricular Assist Device (VAD) can be used to support patients with acute and chronic heart failure. Doctors have gained approximately 20 years of experience with this system at numerous medical centers around the world. One or two Thoratec VADs can be used to provide left, right, or biventricular support. The blood pump is positioned extra corporeally and is connected to tubes (cannulas) inserted into the heart. The pump has a rigid plastic case that contains a flexible pumping sac. Blood is ejected from the pump when the pumping sac is compressed by air from the external control console. Within the inflow and outflow conduits, mechanical valves control the direction of blood flow. The Thoratec VAD has a stroke volume of 65 milliliters. It can be operated at up to 100 beats per minute, resulting in blood flow rates of up to 7 liters per minute.
The Thoratec console has control modules and internal compressors that provide pressure and vacuum conditions to the pump. The drive console delivers air to the blood pump in a pulse-like fashion, causing blood to be ejected into the aorta and/or pulmonary artery. The drive console may be set to three different modes of operation: (i) an asynchronous mode where pumping occurs at a preset rate, (ii) a synchronous mode where pumping is synchronized with the patient's heart rate and (iii) a volume mode where pumping is adjusted according to the left ventricular filling volume. The console continuously displays the ejection pressure, percent ejection time, pump rate, pump flow, and vacuum pressure. Because of the external placement of the pump(s), patient mobility is limited with this system.
Jarvik Heart, Inc. and the Texas Heart Institute began developing the Jarvik 2000 FlowMaker® in 1988. About the size of a "C" battery, the device is a valve-less, electrically powered axial flow pump that fits directly into the left ventricle and continuously pushes oxygen-rich blood throughout the body. To date, patients have been sustained for more than 400 days with this device. The Jarvik 2000 FlowMaker is an axial flow blood pump that uses electrical power to rotate a vaned impeller—the only moving part. The device is 2.5 cm wide, 5.5 cm long, and weighs 85 grams. The impeller is a neodymium-iron-boron magnet, which is housed inside a welded titanium shell. The impeller is supported by ceramic bearings. A small cable, which exits the body through the abdominal walls delivers power to the impeller. All of the blood-contacting surfaces are made of highly polished titanium. The normal operating range for the control system is 8,000 to 12,000 revolutions per minute, which will generate an average pump flow rate of 5 liters per minute. The pump speed is controlled by an analog system controller. The pump speed can be manually adjusted from 8000 to 12000 rpm in increments of 1000. The control unit monitors the pump function and the remaining power in the batteries. Audible and visual alerts notify the user of any problems.
The Levitronix CentriMag Short-term LVAS comprises a single-use centrifugal pump, a motor, and a primary drive console. Compared to other devices, the Levitronix LVAS is unique in that it is designed to operate without mechanical bearings or seals. This is possible because the motor magnetically levitates the impeller, achieving rotation with no friction or wear.
In the United States, the Levitronix CentriMag LVAS is still under investigation for use as a short-term device that would provide circulatory support of up to 14 days for patients with post-cardiotomy cardiogenic shock, i.e. those who have developed heart failure as a result of heart surgery.
The Levitronix CentriMag is an extra-corporeal, continuous-flow, centrifugal-type rotary blood pump. The pump housing and rotor are made of medical-grade polycarbonate, designed for single-use. The only moving component within the pump is the impeller, which is magnetically levitated and rotated in a contact-free manner. The centrifugal pump design permits rotation of the impeller at lower speeds, while still achieving desired flow rates. The pump can rotate at speeds of 1500 rpm to 5500 rpm and can provide flow rates of up to 9.9 liters per minute.
The Levitronix pump causes very little damage to the blood because it does not contain any bearings or seals—components that are known to cause hemolysis and promote thrombus formation. In addition, the pump does not contain any flexing sacs, diaphragms, or valves, minimizing the risk of component failure and device-related adverse effects.
The TandemHeart Percutaneous Ventricular Assist Device (pVAD) differs from other assist devices in that it can be inserted either by cardiovascular surgeons in the operating room or by cardiologists in the cardiac catheterization laboratory. The TandemHeart has been used in post-cardiotomy cardiogenic shock patients, and as a bridge to a definitive therapy. The TandemHeart pVAD provides short-term support from a few hours up to 14 days, giving the heart time to strengthen and potentially regain native function.
The TandemHeart pVAD is an extra-corporeal, continuous-flow centrifugal assist device. Cannulas are inserted percutaneously through the femoral vein and advanced across the intra-atrial septum into the left atrium. The pump withdraws oxygenated blood from the left atrium, propels it by a magnetically driven, six-bladed impeller through the outflow port, and returns it to one or both femoral arteries via arterial cannulas. The pump weighs 8 ounces and is capable of delivering blood flow up to 3.5 liters per minute. The pump also has a proprietary fluid-infusion system that provides cooling and lubrication to the impeller and enhances thromboresistance. The system provides localized anticoagulation to the blood inside the pump, reducing the need for systemic anticoagulation.
The TandemHeart pVAD is operated by a controller console designed to continuously monitor the system. The console also has extensive back-up and fault-management features.
The Bio-Pump was originally developed for cardiopulmonary bypass, but it can be used for up to about a week of circulatory support beyond the surgical setting. The Bio-Pump has been used both in post-cardiotomy cardiogenic shock patients and as a bridge to transplantation for patients who cannot be weaned from the device. This short-term assist device can be implanted in a broad range of patients, from newborns to adults, and can be used alone or along with another Bio-Pump or other type of assist device if biventricular support is needed.
The Bio-Pump is an extra-corporeal, centrifugal device that can provide support for one or both ventricles. Two disposable models are available: the 80-mL model for adults and a 48-mL model for children. The transparent pump housing is shaped like a cone. The pump consists of an acrylic pump head with inlet and outlet ports placed at right angles to each other. The impeller, which is a stack of parallel cones, is driven by an external motor and power console. Rotation of this impeller at high speeds creates a vortex, which drives blood flow in relation to rotational speed. Blood enters through an inlet at the top of the cone and exits via an outlet at the base. The adult model pump can rotate up to 5000 rpm and can provide flow rates of up to 10 liters per minute.
The Bio-Pump console is relatively small and easy to operate, although it does require continuous supervision by specially trained personnel. When fully charged, the system has an internal battery life of 45 minutes. A battery indicator light displays the charge level. A flow probe inserted in the patient's artery allows for a continuous readout of the blood flow rate. The operator can program the console for use in children or adults by selecting a high or low flow rate. The console features a numeric readout and a bar graph that shows flow rate and revolutions per minute.
The Model-7 ALVAD is a pneumatic abdominal left ventricular assist device (ALVAD) that has been used to support post-cardiotomy patients.
The Model-7 ALVAD is a pneumatic, single-chambered implantable blood pump that was placed in the abdomen and connected to the left ventricle by a Dacron tube. Blood from the left ventricle flows through the tube and fills a polyurethane bladder. When air from the driveline fills the space between the bladder and the titanium pump housing, the blood is pumped through a disc-type valve into the aorta and to the body. Polyester fibers coat all of the blood-contacting surfaces, except the valve discs and the inflow and outflow grafts. The fibers promote the development of a cellular lining, which helps prevent blood clots and infection. The console thereof provides variable settings of pump chamber pressurization, pump chamber filling, and pulse duration. The two modes of operation include EKG-triggered pumping that is synchronized with the resting and pumping phases of the left ventricle, or variable fixed-rate asynchronous pumping. Four fail-safe functions are also available in cases of EKG interruption; mechanical or electrical failure; loss of external pneumatic power or loss of AC line power. The internal power supplies allow for portable operation for up to 50 minutes.
The Impella Recover LD/LP 5.0 Support System has been developed to address the need for ventricular support in patients who develop cardiogenic shock—heart failure after heart surgery—and who have not responded to standard medical therapy. The system is designed to provide immediate support and restore hemodynamic stability for a period of up to 7 days. Used as a bridge to therapy, it allows time for developing a definitive treatment strategy.
The Impella Recover system is a miniaturized impeller pump located within a catheter. The device can provide support for the left side of the heart using either the Recover LD 5.0 that is implanted via direct placement into the left ventricle, or the Recover LP 5.0 LV that is placed percutaneously through the groin and positioned in the left ventricle. The microaxial pump of the Recover LP/LD 5.0 can pump up to 4.5 L/min at a speed of 33,000 rpm. The pump is located at the distal end of a 9 Fr catheter. At its largest outside diameter, which contains the pump housing, the Impella measures 21 Fr. The catheter shaft contains the electrical connections for the pump motor and sensor as well as for a separate tube used for transfer of purged fluid.
Clinical use of the Hemopump in patients began at the Texas Heart Institute in April 1988 as a short-term treatment for cardiogenic shock. Later, the device was evaluated as an alternative to standard cardiopulmonary bypass. Today, the Hemopump is no longer used, but researchers have applied its design to other circulatory assist devices. The innovative design of the Hemopump included a tiny axial flow pump that provided up to 3.5 liters per minute of circulatory support. The first patient treated with the Hemopump was a 61-year-old man with profound heart failure related to donor heart rejection. His life was sustained with the Hemopump for two days, and he was eventually discharged from the hospital. The catheter-mounted, intra-aortic axial flow pump thereof is about the size of the eraser on an ordinary pencil. It was inserted through a small incision in the femoral or external iliac artery, advanced to the aorta, and positioned across the aortic valve. A screw element rotated 17,000 to 25,000 times per minute, drawing blood from the left ventricle and ejecting it into the descending aorta. Power was provided through a percutaneous driveline connected to an external electromechanical console. The console produced flows of up to 3.5 liters per minute and assumed up to 80% of the left ventricle's workload.
Dr. Adrian Kantrowitz introduced the intra-aortic balloon pump (IABP) in the late 1960s as a simple yet effective device to increase coronary perfusion. Because it is easy to insert, the IABP is the most widely used form of mechanical circulatory support. At the Texas Heart Institute, the IABP is now used in more than 450 patients each year. Although the IABP was first used for surgical patients, the pump can now be used along with interventional cardiology procedures and medications. Indications for its use include failure to wean from cardiopulmonary bypass, cardiogenic shock, heart failure, acute heart attack, support during high-risk percutaneous transluminal coronary (balloon) angioplasty, rotoblator procedures, and coronary stent placement.
The IABP is a polyethylene balloon mounted on a catheter, which is generally inserted into the aorta through the femoral artery in the leg. The pump is available in a wide range of sizes (2.5 cc to 50 cc) that will fit patients of any age and size. The balloon is guided into the descending aorta, approximately 2 cm from the left subclavian artery. At the start of diastole, the balloon inflates, augmenting coronary perfusion. At the beginning of systole, the balloon deflates; blood is ejected from the left ventricle, increasing the cardiac output by as much as 40 percent and decreasing the left ventricular stroke work and myocardial oxygen requirements. In this manner, the balloon supports the heart indirectly. The balloon is inflated with helium, an inert gas that is easily absorbed into the bloodstream in case of rupture. Inflation of the balloon can be triggered according to the patient's electrocardiogram, their blood pressure, a pacemaker (if they have one), or by a pre-set internal rate.
The IABP is driven by the balloon pump console. The operating controls are located on a touch pad below the display monitor and can be programmed to produce rates as high as 140 beats per minute. The on-board battery provides power for up to 2 hours. The New CS100 IntelliSync console, with one-button start up, automatically adapts to patients' changing conditions.
Similarly, U.S. Pat. No. 6,406,422 to Landesberg describes a ventricular assist method and apparatus having an expandable intraventricular chamber, essentially a single chambered balloon, for dilating a heart chamber. The device described is not intended to replace the entire function of a failing heart but rather to add additional cardiac input.
PCT/IL2004/000500 (WO 2005/002645) to Ben Shalom et al. describes a hydraulic system and method for supporting a body organ, the system comprising a closed loop liquid-tight tubing fitted with a pressure generator for propelling a liquid through the system, an organ engaging member connected to a pressure chamber via a discharge valve for controlled discharge of liquid into the organ inflatable pressure member. The organ-engaging member includes an inflatable pressure member suited for receiving the organ. There is further provided at least one control valve for selectively controlling liquid flow through the system and a controller for selectively controlling the discharge valve and the at least one control valve. The system may be used as cardiac assist device or for massaging a limb to stimulate blood flow therethrough. The device described has one pulsation chamber, and there is an inherent lack of flexibility therewith in that the system described includes no features for adapting the prosthetic ring to specific diseased hearts.
U.S. Pat. No. 4,192,293 to Asrican, describes a cardiac assist device that operates by cyclically exerting pressure through an implanted inflatable sheath, which surrounds the myocardium. The sheath is rigid and encloses a bladder or plurality of bladders into which a fluid, either in the form of an inert gas or a liquid is pulsed, with a time displacement curve similar or identical to the contraction-distension characteristics exhibited normally by the myocardium during a cardiac cycle. Pulsing is triggered by the EKG R-spike of the patient, which operates a valve. In order to provide adequate fluid volume for the required pressure through the valve, an elastic fluid reservoir is provided. The cyclical pressure is generated by an elastic wall. It is therefore a fixed pressure that is difficult to match to a specific heart, and in practice will only provide a very approximate match. Furthermore, since clearly the appropriate cardiac assistance for an individual varies considerably throughout the day, between sleeping and walking for example, and depends, inter alia, on the amount of exertion and the quality of the air breathed, such a system will only very approximately match actual requirements.
WO 98/55165 to Seare and Woodard, describes a cardiac assist device with independently operable pneumatic or hydraulic chambers. In consequence thereof, the pressure provided at different positions on heart may be varied. The overall shape of the device described may be cup shaped, frustoconical, cylindrical etc. and may be tailored to the shape of the individual heart to provide a tailored solution for a specific diseased heart.
U.S. Pat. No. 5,713,954 to Rosenberg et al. describes a cuff that may be inflated and deflated using hydraulic fluid, which is designed to be placed around the natural heart. The cuff comprises a plurality of tubular segments that are variably fluid filled. Hydraulic pumps and rotating valves are described. Actuators and electronic control are also discussed.
U.S. Pat. No. 6,206,820 to Kazi describes an external prosthetic ring having elastic, fluid-fillable chambers supported by mechanical abutments, essentially inelastic plates, for cardiac assist purposes. The device described includes a plurality of fluid fillable chambers, and can be engineered to apply local pressure on part of the heart only, such as to the left ventricle, for example.
U.S. Pat. No. 6,251,061 to Hastings et al. describes a cardiac assist device using field controlled fluid. U.S. Pat. No. 6,508,756 to Kung et al. describes yet another cardiac assist device that may be active or passive.
Prior art cardiac assist systems described hereinabove suffer from a common drawback in that the diseased heart is subjected to a sudden external contracting force. This is somewhat unnatural and may be a contributory factor to the low life-expectancy of recipients using such systems.
Prior art for leg massaging includes U.S. Pat. No. 5,672,148 to Maunier, which describes a hydraulic device for lymphatic drainage and massage of the human body that comprises a chamber with outer quasi-rigid & inner supple walls, filled with porous material through which a viscous fluid is circulated. The device provides hydrostatic pressure around the limb and does not provide different pressures to different areas.
U.S. Pat. No. 5,437,610 to Cariapa et al. describes an extremity pump apparatus for the treatment of edema. A plurality of bladders arranged in a bandage for wrapping around a limb is described. The closing arrangement allows the bandage to be fitted to limbs of different sizes. The plurality of bladders is connected via a manifold and valves to a hydraulic pressure source. The prosthetic is either cylindrical or frustoconical.
U.S. Pat. No. 6,589,194 to Calderon et al. describes a device, essentially a boot, for promoting circulation by externally massaging a leg. The chambers thereof are air-filled. The pumping action is activated by movement of the wearer, particularly by wearer transferring weight from one foot to another.


A method is provided for plastic forming of a ball which forms a connecting element or part of a connecting element intended for connecting at least two components. At least some of the energy required for the plastic forming of the ball is introduced into the ball by way of ultrasound.

The present invention relates to a component connection including a first component having a through-hole, and a second component having a hole, and a connecting element connecting the two components. The present invention also relates to a method for the plastic forming of a ball.
A component connection of this type and a method of this type are known from the prior, non-previously-published, German patent application DE 10 2014 211 660.
Rivets in a wide variety of shapes and manifestations have already been used for more than a hundred years for the connection of components. When riveting components, a rivet is inserted into holes which are oriented concentrically in relation to one another and are provided in the components to be connected to one another. The rivet is plastically deformed by the application of a pressure or a force.
It is an object of the invention to provide a component connection in which two components are connected to one another in a different, cost-effective manner. It is a further object of the invention to specify a method which is suitable therefor.
This and other objects are achieved by a component connection as well as a method for plastic forming of the ball in accordance with embodiments of the invention.
The starting point of the invention is a component connection, including a first component having a through-hole, and a second component having a hole. The hole provided in the second component may likewise be a through-hole or a simple blind hole. The component connection further includes a "connecting element" connecting the two components. There is a form fit between the connecting element and at least one of the two components. Furthermore, it can be provided that there is a frictional connection between one or both components and the connecting element. Furthermore, it can be provided that there is a form fit and possibly also a frictional connection between the connecting element and both components.
An aspect of the invention consists in the fact that the connecting element or part of the connecting element has been produced by ultrasonic plastic deformation of a ball. "Starting material" of the connecting element may therefore be a ball, or part of the connecting element may be formed initially by a ball. "Starting material" therefore does not necessarily have to be a simple ball. It is also contemplated for the ball to be part of a more complex element (e.g. a bolt or the like may protrude from the ball).
Ultrasonic energy is introduced into the ball by way of an ultrasonic sonotrode and makes the ball undergo vibrations to such an extent that it becomes at least so "soft" that it can be plastically deformed. After the plastic deformation of the ball, the latter adopts a shape which projects over the through-hole provided in the first component in a form-fitting manner or like a rivet and extends through the through-hole provided in the first component into the through-hole provided in the second component. As has already been mentioned, a frictional connection may arise between the connecting element, formed from the ball by forming of the ball, and the second component. If the hole provided in the second component is likewise a through-hole, it can be provided that the plastically deformed connecting element extends through the two holes and projects over both holes in a form-fitting manner or like a rivet.
A significant advantage of the invention consists in the fact that the balls (irrespective of the material of the balls) are generally extremely inexpensive mass-produced goods, which can be purchased "at price per kilo". The invention is therefore suitable in particular for high-volume applications.
On account of the complete symmetry of a ball, the latter can be "shaped" or deformed very easily by way of a spherical segment-shaped sonotrode. By way of example, a ball can be sucked in by way of a suction device which is integrated in the sonotrode or is arranged on the sonotrode, "softened" by ultrasound, and then shaped, i.e. deformed. This operation can be effected in a fully automated manner by use of a robot.
The invention can be employed in conjunction with a very wide variety of ball materials. The ball can consist of a plastics material, for example. As an alternative thereto, the ball can also consist of a metal or of an alloy. The invention can be employed in particular in conjunction with aluminum balls, copper balls or steel balls.
The invention is also universally usable with respect to the materials of the two components. By way of example, the first and/or the second component can consist of a metal, for example steel or aluminum, or of plastic, in particular of a fiber-reinforced plastic. In particular, the first component can consist of a different material to the second component ("mixed construction connection").
One of the components or both components may be body components of a vehicle. However, the invention can be used not only in vehicle construction but also quite generally, where what is involved is the connection of two components to one another in a simple and cost-effective manner.
The ball can be made to undergo vibrations by way of a sonotrode. By way of example, it is contemplated that the direction of vibrations of the sonotrode is parallel to an axis running through the center points of the two holes, i.e. substantially perpendicular to the two components in the region of the holes. As an alternative thereto, this can also be carried out using a "rotary sonotrode", which makes the ball undergo torsional vibrations ("twisting ultrasound").
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.

Component connection and method for the plastic forming of a ball

Bayerische Motoren Werke Aktiengesellschaft


Binning polygons in a three-dimensional graphics system includes constructing a first bounding box around a first-level polygon, the first bounding box including tiles that contain the first-level polygon, subdividing the first-level polygon into second-level polygons if the first bounding box exceeds a predetermined size, and constructing bounding boxes around each second-level polygon. The second bounding box includes fewer tiles than the first bounding box.

A virtual 3D model (or simply "3D model") is comprised of polygons, such as triangles, which represent the skin of the 3D model. A rasterization engine draws polygons from the 3D model onto a two-dimensional (2D) surface, such as a computer screen. Typical rasterization engines draw the entire frame buffer at once. A more efficient method is to break up the frame buffer into individual subsections (tiles) and to render them individually. Each tile includes one or more polygons or, more typically, a portion of one or more polygons.
To reduce the amount of tiles that each polygon is assigned to, a polygon binning process may be used. A polygon binning process excludes tiles that do not include any polygons or portions thereof prior to rasterization. The binning process also accomplishes some rasterization setup by identifying which polygons are contained by each tile. By doing this, the amount of processing that must be performed by the rasterization engine is reduced.
Like reference numerals in different figures indicate like elements.

Polygon binning process for tile-based rendering


An electrical plug comprising: a socket part (5a, 5b, 5c, 5d) having a plurality of electrical plugs configured for directly or indirectly plugging into a mains electrical socket; a device part (3) having at least one power output configured for direct or indirect coupling to an electrical device; wherein the socket part is separate and releasable from the device part, and the socket part and device part comprise respective parts of two two-part engagement formations that are engageable to physically and electrically couple the socket part to the device part.

We have previously disclosed a novel folding plug (see www.themu.co.uk and UK Patent No. 2467644) that is greatly reduced in size in comparison to a traditional three-pin plug of the type that may be plugged into mains socket outlets of the type that are common in the United Kingdom.
Whilst this arrangement greatly reduces the size of such plugs, it would be useful if a greater range of devices could be powered by such an arrangement.
It would also be useful if the compact nature of our previously proposed Mu adaptor could be applied to plugs that are configured for plugging into other types of mains electrical socket. Lastly, it would be particularly useful if a system could be devised that allowed a greater range of devices to be powered, and which provided compact plugs for plugging into other types of mains electrical socket.
Our co-pending UK and International applications (GB1416882.7 and PCT/EP2014/070418, the contents of each of which are incorporated herein (in their entirety) by reference) disclose a power supply system that has been devised with the foregoing problems in mind. In very general terms, this system comprises a plurality of socket parts and a plurality of device parts, and the socket parts can interchangeably be coupled to device parts to provide the user with a desired pin configuration and power output combination. The teachings of the invention disclosed in these application is also applicable to a given socket part that can interchangeably be coupled to different device parts, thereby providing the user with a desired power output for a given pin configuration.
Whilst the arrangements disclosed in these co-pending applications functions admirably, the applicant's continuous program of improvement has identified that the coupling between the aforementioned socket and device parts could be further enhanced. The present invention has been devised with the foregoing in mind.


In a method for producing an auxiliary gate lightly doped drain structure, a gate region is placed on a substrate between two source/drain regions. A first implant of atoms is made into the substrate on two sides of the gate region. Sidewalls are formed on the two sides of the gate region. Auxiliary gate regions are formed over the sidewalls. The auxiliary gate regions are separated from the gate region by the sidewalls. Dielectric regions are formed over the auxiliary gate regions. A second implant of atoms is performed into the substrate on two sides of the dielectric regions. The sidewalls and the auxiliary gate regions are composed of resistive material.

The present invention concerns an auxiliary gate lightly doped drain (AGLDD) process for use in producing high reliability submicron metal oxide silicon field effect transistors (MOSFETs).
The use of gate overlapped lightly doped drain (GOLDD) processes to increase reliability of high speed submicron MOSFETs has been investigated. For example, in one process, referred to as total overlap with polysilicon spacer (TOPS), three deposits of polysilicon are use to form a gate region of a transistor which overlaps the source and drain region of the transistor. See J. E. Moon, et al., A New LDD Structure: Total Overlap with Polysilicon Spacer (TOPS), IEEE Electronic Device Letters, May 1990, pp. 221-223. See also T. Y Huang: A novel SubMicron LDD Transistor with inverse-T Gate Structure, IEDM, 1986, pp. 742-745, and R. Izawa, et. al., The Impact of Gate-Drain overlapped LDD(GOLD)/For Deep SubMicron VLSIs, IEDM 1987, pp. 38-41.
However, in such GOLDD structures gate-drain overlap capacitance and gate-source overlap capacitance can result in slow circuit operation speed. In order to reduce gate-drain overlap capacitance and gate-source overlap capacitance, AGLDD processes have been suggested. See for example, Matsatka Minami, Yasuo Sawahata, Hiroshi Matsuki and Takahiro Naganoi, A High Speed and High Reliability MOSFET utilizing an Auxiliary Gate, 1990 Symposium on VLSI Technology, pp. 41-42; and I. C. Chen, J. P. Lin, and C. W. Teng, A Highly Reliable 0.3 .mu.m N-channel MOSFET Using Poly Spacers, 1990 Symposium on VLSI Technology, pp. 39-40.
In the above-cited AGLDD processes, an auxiliary resistor is inserted between the auxiliary and main gates. The value of the auxiliary resistance is selected so that the RC time constant of the auxiliary resistance and the gate-source/drain overlap capacitance is longer than the circuit delay time. This prevents transient circuit action from being affected by the gate-source/drain overlap capacitance. In DC circuit action, however, the auxiliary gate works to increase the high hot-carrier reliability of the circuit.
One drawback of the above-cited prior art AGLDD process described by Matsatka Minami, Yasuo Sawahata, Hiroshi Matsuki and Takahiro Naganoi, High Speed and High Reliability MOSFET utilizing an Auxiliary Gate, 1990 Symposium on VLSI Technology, pp. 41-42, is that the value of the auxiliary resistance is dependent upon a layer of oxide on the sides of the main gate. This oxide layer thickness, however, is difficult to control in a manufacturing environment.

Method of fabricating auxiliary gate lightly doped drain (AGLDD) structure with dielectric sidewalls


A motorcycle wheel disk lock reminder system for reminding a user that a disk lock is mounted to the wheel of the user's motorcycle so that the user does not drive the motorcycle with the disk lock attached to the wheel. The motorcycle wheel disk lock reminder system includes a disk lock adapted for attachment to a wheel of a motorcycle. The disk lock has a slot therein into which an insertion tab outwardly extending from an inner face of a reminder unit is removably inserted. The insertion tab of the reminder unit is also insertable into an ignition keyhole of the motorcycle subsequent removable of the insertion tab from the slot of the disk lock to prevent insertion of an ignition key into the ignition keyhole without prior removal therefrom of the insertion tab of the reminder unit.

1. Field of the Invention
The present invention relates to motorcycle wheel disk lock reminder systems and more particularly pertains to a new motorcycle wheel disk lock reminder system for reminding a user that a disk lock is mounted to the wheel of the user's motorcycle so that the user does not drive the motorcycle with the disk lock attached to the wheel.
2. Description of the Prior Art
The use of motorcycle wheel disk lock reminder systems is known in the prior art. More specifically, motorcycle wheel disk lock reminder systems heretofore devised and utilized are known to consist basically of familiar, expected and obvious structural configurations, notwithstanding the myriad of designs encompassed by the crowded prior art which have been developed for the fulfillment of countless objectives and requirements.
Known prior art includes U.S. Pat. No. 4,665,728; U.S. Pat. No. 5,563,387; U.S. Pat. No. Des. 270,245; U.S. Pat. No. Des. 326,045; U.S. Pat. No. 4,838,059; and U.S. Pat. No. 1,590,981.
While these devices fulfill their respective, particular objectives and requirements, the aforementioned patents do not disclose a new motorcycle wheel disk lock reminder system. The inventive device includes a disk lock adapted for attachment to a wheel of a motorcycle. The disk lock has a slot therein into which an insertion tab outwardly extending from an inner face of a reminder unit is removably inserted. The insertion tab of the reminder unit is also insertable into an ignition keyhole of the motorcycle subsequent removable of the insertion tab from the slot of the disk lock to prevent insertion of an ignition key into the ignition keyhole without prior removal therefrom of the insertion tab of the reminder unit.
In these respects, the motorcycle wheel disk lock reminder system according to the present invention substantially departs from the conventional concepts and designs of the prior art, and in so doing provides an apparatus primarily developed for the purpose of reminding a user that a disk lock is mounted to the wheel of the user's motorcycle so that the user does not drive the motorcycle with the disk lock attached to the wheel.

Motorcycle wheel disk lock reminder system


An anesthesia conduit for connecting a tracheal tube and a gas circuit. The connector includes a flexible portion integral with a substantially rigid longitudinally extending portion. The longitudinally extending portion may include two ports, one connected to apparatus such as an respiratory gas monitor, and the other configured such that suction catheters can be inserted into the conduit and tracheal tube.

1. Field of the Invention
The present invention is directed to a connector from a tracheal tube to the anesthesia machine or respirator, herein referred to as an anesthesia conduit.
2. Description of the Related Art
Tracheal tubes are used to administer anesthetic gas during surgical procedures. Tracheal tubes are also used to provide oxygen from a respirator in order to assist patients who are experiencing breathing difficulty or weaning patients off respirators. The distal end of such a tube is positioned in the trachea of a patient, and hence the name. The distal end of one type of tracheal tube, a tracheostomy tube, may be inserted into the patient's trachea through an opening in the neck. The distal end of another type of tracheal tube, an endotracheal tube, may be inserted into the trachea through the patient's nose or mouth. The proximal end of either type of tracheal tube may be connected to a respirator or to an anesthesia circuit via a connector tube, thereby forming a path from the gas circuit to the patient's trachea.
During surgery, it is necessary to monitor a patient's respiration and vital signs. Respiration and vital sign monitoring entails measuring CO.sub.2, O.sub.2, N.sub.2 O and anesthesic gas, in addition to other vital signs, such as pulse and blood pressure. Airway pressure and volume are also monitored. Such monitoring is typically performed by a respiratory gas monitor (RGM), such as is well known in the art. An example of one such monitor is the Ohmeda.TM. 5250 RGM. In order to connect the RGM to the path between the gas circuit and the patient, the RGM includes an adapter which is placed between the tracheal tube and the gas circuit. The RGM adapter includes a port which is connected to the RGM by a tube. As illustrated in FIG. 1, RGM adapters often include a male end and a female end so that the adapter 1 is arranged in series with the tracheal tube 2, connector tube 3 and gas circuit 4.
Suction may also be needed at some location between the tracheal tube 2 and the gas circuit in order to remove certain secretions from the lungs, mouth, etc. Thus, in addition to the RGM adapter, a suction adapter, having a port which can be used for suctioning tracheal and lung secretions is to be incorporated into the connector tube, RGM adapter and gas circuit.
In order to allow tubing from the gas circuit to be positioned without dislodging the tracheal tube, flexible tubing 5 is typically inserted between the connector tube 3 and the gas circuit 4. Such an arrangement is illustrated in FIG. 2. Additionally, as illustrated in FIG. 3, the flexible tubing 5, RGM adapter 1 and suction adapter 1 are connected in series (from up to three to four different connection sites) and used to form a pathway between the tracheal tube 2 and the gas circuit 4.
While useful for their intended purposes, there are a number of disadvantages inherent in placing RGM adapters, suction adapters and flexible tubing between a tracheal tube and a gas circuit. For example, each time one of these elements is added, an additional discontinuity, or junction, is formed between the tracheal tube and the gas circuit. Such junctions cause a number of problems during surgery; they are sources of disconnections and subsequent leaks. Disruption of delivery of oxygen and anesthesia agents to the patient creates a hazard to the patient and to operating room personnel, and contaminates the operating room environment. Accordingly, this path between the tracheal tube and the gas circuit must be continuously monitored for leaks and disconnections by the anesthesiologist or other personnel, particularly if the head and/or patient is turned in different directions during surgery. Thus, even when no leaks or disconnections occur at the junctions, the mere possibility of such an occurrence serves as a distraction.
Finally, the accuracy of the RGM depends upon the distance of the RGM adapter from the gas source, i.e. the patient's trachea. The closer the adapter is to the source, the more accurate the RGM's measurements. However, it is common for RGM adapters to be inadvertently positioned on the distal end of the connector tube, the point farthest from the patient. Such malpositioning needlessly increases the distance between the RGM adapter and the gas source, thereby decreasing the accuracy of the RGM's measurements.


An in-line network tap includes a network tap chip that is configured to analyze or otherwise process data packets as the data packets are transmitted within a network. The network tap chip can be embedded within a communication cable, such as an Ethernet or USB cable, either within the flexible cable portion of the cable or within a connector on either end of the communication cable. Alternatively, the network tap chip can be embedded within a transceiver. The in-line network tap can perform various processing including monitoring network performance, facilitating remote troubleshooting, data buffering, and intrusion detection and prevention.

A network tap can be connected to a network switch and used to monitor and perform diagnostics on a network. Existing network taps are implemented as a separate hardware device that requires a direct power supply. When connected to the network, the device obtains a new Internet Protocol (IP) address and Media Access Control (MAC) address to enable the device to communicate with a monitor or diagnostics operator. Because existing network taps are implemented as separate devices, they are easily detectable. Furthermore, MAC address locking or IP address locking can prevent a network tap from communicating over the network.


In a circuit arrangement for reproducing audio information signals recorded in one or a plurality of audio channels on a movable sound carrier, the sound carrier being moved at a normal reproduction speed during reproduction, the arrangement including a noise reduction circuit, each audio channel of the arrangement including an RC network (10, 30) with at least one RC filter, there is provided a gap detection circuit integrated in the reproduction circuit arrangement. This gap detection circuit jointly uses parts of the noise reduction circuit, at least one or a plurality of RC filters of the RC network(s) (10, 30) of the noise reduction circuit, during the time intervals in which gaps in the audio information signals are to be detected by the pause detection circuit when the sound carrier is moved at a higher speed than the normal reproduction speed.

1. Field of the Invention
The invention relates to a circuit arrangement for reproducing audio information signals recorded in one or a normal plurality of audio channels on a movable sound carrier while the sound carrier is moved with a reproduction speed during reproduction, this arrangement comprising a noise reduction circuit and in this arrangement each audio channel having an RC network that includes at least one RC filter.
2. Description of the Related Art
This type of circuit arrangements for reproducing audio information signals recorded on a sound carrier, which arrangements comprise a noise reduction circuit, have gained ground for use in tape recorders, more specifically, cassette recorders. In this example, the movable sound carrier is understood to be a magnetic tape which is moved past a magnetic head whose output signals are applied to the reproduction circuit arrangement comprising a noise reduction circuit. With such a circuit it may be a matter of noise cancellation according to one of the Dolby systems. In these Dolby systems the treble is lowered on the reproduction side to a greater or lesser extent in dependence on its level, so that, more specifically, the tape noise is reduced simultaneously, Such noise reduction circuits require various filters which have different time constants. Therefore, at least one RC network having one or a plurality of RC filters is provided for each audio channel. A great variety of circuits of this type are known.
In addition, circuits are known which are used for recognizing gaps in the audio information signals when the sound carrier has an increased speed relative to the normal reproduction speed. In the above example of the cassette tape recorder this means that the tape is moved e.g. with a rewinding speed while the magnetic head picks up the audio information signals from the tape in a similar manner that it does with the reproduction speed. In this case, however, not the audio information signals as such are to be evaluated, but there should be detected when gaps occur in the audio information signals. In this manner, for example, individual music titles can be located on the tape. Such gap detection circuits are also known in a great variety of embodiments.

Reproduction circuit arrangement having a noise reduction circuit and a gap detection circuit


A control apparatus for a vehicle drive-force transmitting apparatus which establishes selectively a first state in which a drive force is transmitted by a gear mechanism and a second state in which the drive force is transmitted by a continuously-variable transmission mechanism. The control apparatus executes a shift-up action requiring the first state to be switched to the second state, in (a) a case in which a state of the drive-force transmitting apparatus satisfies a first condition that a gear ratio of the continuously-variable transmission mechanism is not lower than a first gear ratio value and in (b) a case in which the state of the drive-force transmitting apparatus satisfies a second condition that a lap-down control is executed with the gear ratio of the continuously-variable transmission mechanism being not lower than a second gear ratio value that is lower than the first gear ratio value.

There is known a control apparatus for a drive-force transmitting apparatus that is to be provided in a vehicle having a drive force source and drive wheels, wherein the drive-force transmitting apparatus includes: an input rotary member to which a drive force is to be transmitted from the drive force source; an output rotary member from which the drive force is to be outputted to the drive wheels; a continuously-variable transmission mechanism; and a gear mechanism configured to provide at least one gear ratio, and wherein the drive-force transmitting apparatus defines a plurality of drive-force transmitting paths that are provided in parallel with each other between the input rotary member and the output rotary member. The plurality of drive-force transmitting paths include a first drive-force transmitting path through which the drive force is to be transmitted by the gear mechanism and a second drive-force transmitting path through which the drive force is to be transmitted by the continuously-variable transmission mechanism, such that a selected one of the first and second drive-force transmitting paths is established. WO2014/147779 discloses such a control apparatus for a drive-force transmitting apparatus that is to be provided in a vehicle. This publication of International Patent Application discloses that, in the drive-force transmitting apparatus in which a gear mechanism and a continuously-variable transmission mechanism are provided to be parallel with each other, the continuously-variable transmission mechanism provides a continuously-variable gear ratio which is variable within a given range and which is lower than a gear ratio provided by the gear mechanism. The publication also discloses that, when a shift-up action requiring the selected drive-force transmitting path to be switched from the first drive-force transmitting path (through which the drive force is to be transmitted by the gear mechanism) to the second drive-force transmitting path (through which the drive force is to be transmitted by the continuously-variable transmission mechanism) is to be executed, the execution of the shift-up action is started after the continuously-variable transmission mechanism has established a highest gear ratio value that corresponds to a maximum value within the given range of the continuously-variable gear ratio. It is noted that the term "gear ratio" is defined as "rotational speed of input-side rotary member/rotational speed of output-side rotary member". For example, the gear ratio of the above-described drive-force transmitting apparatus is defined as "rotational speed of the input rotary member/rotational speed of the output rotary member". A vehicle running speed could be lower as the gear ratio is higher, and could be higher as the gear ratio is lower. The above-described highest gear ratio value of the continuously-variable transmission mechanism can be expressed also as a lowest-speed gear ratio value.

Control apparatus for vehicle drive-force transmitting apparatus


A vehicular airbag device includes an airbag and an opening degree change portion. The airbag is folded and accommodated in an accommodation portion provided in front of a vehicle seat. The airbag is deployed toward an occupant seated in the vehicular seat by being supplied with a gas when a head-on collision occurs, and has a vent hole that allows the gas to be discharged in restraining the occupant. The opening degree change portion changes an opening area of the vent hole in accordance with a direction of impact of an upper body of the occupant with the airbag during deployment of the airbag.

1. Field of the Invention
The invention relates to a vehicular airbag device.
2. Description of the Related Art
In a conventional vehicular airbag device, a variable vent hole is provided so that the vent hole, which is open during the initial stages of airbag deployment, becomes closed by a strap while the airbag expands (see U.S. Pat. No. 7,347,450). The strap is coupled to the lower portion of the deployed airbag on it vehicle rear side and to the vent hole.
In a vehicle equipped with the vehicular airbag device, the airbag deploys between the passenger and an instrument panel when a head-on collision occurs to restrain the upper body of a passenger sitting in a vehicular seat. It should be noted herein that if the passenger sitting in the vehicular seat does not wear a seat belt in a jurisdiction where the use of a seat belt is not legally required, the body of the passenger moves wholly forward with respect to the vehicle due to inertia, and the upper body of the passenger wholly impacts with the airbag. In the structure of the airbag according to the related art, when the strap that is coupled to the lower portion of the airbag on the vehicle rear side is slack, the vent hole opens due to a rise in internal pressure resulting from the impact of the upper body of the passenger when the upper body of the passenger comes into contact with the airbag.
However, if the passenger sitting in the vehicular seat is restrained by the seat belt, the lower portion of the upper body of the passenger is restrained from moving forward with respect to the vehicle, and the direction of impact (the route of impact) of the upper body of the passenger differs from that when the passenger is not restrained by the seat belt. Therefore, the effective stroke of the airbag in restraining the passenger changes, and the reactive force of the airbag necessary to appropriately restrain the passenger changes as well. Further, when the passenger sitting in the vehicular seat is restrained by the seat belt, the lower portion of the upper body of the passenger is restrained from moving forward with respect to the vehicle. In the structure according to the related art, therefore, it is considered that the strap is unlikely to slack and the vent hole does not easily open.


A method for processing an interrupt by a virtualization platform, and a related device, where the method includes determining an nth physical central processing unit (pCPU) from U target pCPUs when an ith physical interrupt occurs in a jth physical input/output device, setting the nth pCPU to process the ith physical interrupt, determining an ith virtual interrupt according to the ith physical interrupt, and determining an mth virtual central processing unit (vCPU) from V target vCPUs such that a kth virtual machine (VM) uses the mth vCPU to execute the ith virtual interrupt, where U, V, i, j, k, m, and n are positive integers while U and V are greater than or equal to 1.

A virtualization technology is a decoupling technology in which a bottom-layer hardware device is separated from an upper-layer operating system and application program. As one of important bottom-layer technologies for supporting a currently popular cloud computing platform, the virtualization technology may greatly improve resource utilization of a physical device. Compared with a conventional physical server, a virtual machine (VM) has better performance in the terms of isolation and encapsulation, and may save information of the whole VM in a virtual disk image (VDI), which may facilitate operations such as a snapshot, a backup, a clone, and distribution for the VM. An overhead is generated by virtualization, thereby causing that with a same configuration, performance of a VM is poorer than performance of a physical machine. How to effectively improve performance of a VM is a problem that needs to be solved in this field.

Method for processing interrupt by virtualization platform, and related device


A process is disclosed for creating semiconductor devices such as RFID assemblies wherein an array of dies mounted to a substrate is spaced apart at a first pitch, and the substrate is removed after the positions of the dies in the array is fixed by a solidifiable substance. The solidifiable substance is then removed without changing the relative positions of the dies in the array. All or a selected portion of the array of dies is then electrically attached to a plurality of straps or interposers arranged in a corresponding array. The spacing, or pitch, between the dies in the die array may be changed before or after the substrate is removed to match the pitch of the straps or interposers in the corresponding array. An RFID device created using the process inventive is also disclosed.

Automatic identification of products has become commonplace. For example, the ubiquitous barcode label, placed on food, clothing, and other objects, is currently the most widespread automatic identification technology that is used to provide merchants, retailers and shippers with information associated with each object or item of merchandise.
Another technology used for automatic identification products is Radio Frequency Identification (RFID). RFID uses labels or "tags" that include electronic components that respond to radio frequency commands and signals to provide identification of each tag wirelessly. Generally, RFID tags and labels comprise an integrated circuit (IC, or chip) attached to an antenna that responds to a reader using radio waves to store and access the ID information in the chip. Specifically, RFID tags and labels have a combination of antennas and analog and/or digital electronics, which often includes communications electronics, data memory, and control logic.
One of the obstacles to more widespread adoption of RFID technology is that the cost of RFID tags are still relatively high as lower cost manufacturing of RFID tags has not been achievable using current production methods. Additionally, as the demand for RFID tags has increased, the pressure has increased for manufacturers to reduce the cost of the tags, as well as to reduce the size of the electronics as much as possible so as to: (1) increase the yield of the number of chips (dies) that may be produced from a semiconductor wafer, (2) reduce the potential for damage, as the final device size is smaller, and (3) increase the amount of flexibility in deployment, as the reduced amount of space needed to provide the same functionality may be used to provide more capability.
However, as the chips become smaller, their interconnection with other device components, e.g., antennas, becomes more difficult. Thus, to interconnect the relatively small contact pads on the chips to the antennas in RFID inlets, intermediate structures variously referred to as "straps," "interposers," and "carriers" are sometimes used to facilitate inlay manufacture. Interposers include conductive leads or pads that are electrically coupled to the contact pads of the chips for coupling to the antennas. These leads provide a larger effective electrical contact area between the chips and the antenna than do the contact pads of the chip alone. Otherwise, an antenna and a chip would have to be more precisely aligned with each other for direct placement of the chip on the antenna without the use of such strap. The larger contact area provided by the strap reduces the accuracy required for placement of the chips during manufacture while still providing effective electrical connection between the chip and the antenna. However, the accurate placement and mounting of the dies on straps and interposers still provide serious obstacles for high-speed manufacturing of RFID tags and labels. Two challenging areas currently facing manufacturers include:
1) Die Attachment: Accurately positioning dies (i.e., chips) for attachment to strap leads is difficult to achieve at the speeds needed to achieve high volume manufacturing.
2) Bonding: It is difficult to accurately bond, cure, and electrically connect the chips to strap leads at rates necessary to achieve high volume manufacturing.
Several possible high-speed strap assembly strategies have been proposed. The first approach, which uses "pick-and-place" machines typically used in the manufacturing of circuit boards for picking up electronic components and placing them on circuit boards, is accurate, but requires expensive machines that ultimately do not deliver a sufficient throughput to justify the increased cost. Another approach, referred to as a "self-assembly process," is a method in which multiple chips are first dispersed in a liquid slurry, shaken and assembled into a substrate containing chip receiving recesses. Some current processes are described in U.S. Pat. No. 6,848,162, entitled "Method and Apparatus for High Volume Assembly of Radio Frequency Identification Tags," issued to Arneson, et al. on Feb. 1, 2005; U.S. Pat. No. 6,566,744, entitled "Integrated Circuit Packages Assembled Utilizing Fluidic Self-Assembly," issued to Gengel on May 20, 2003; and, U.S. Pat. No. 6,527,964, entitled "Methods and Apparatuses for Improved Flow in Performing Fluidic Self Assembly," issued to Smith et al. on Mar. 4, 2003.
Accordingly, there is a long-felt, but as yet unsatisfied need in the RFID device manufacturing field to be able to produce RFID devices in high volume, and to assemble them at much higher speed per unit cost than is possible using current manufacturing processes.

Method and apparatus for creating RFID devices


An improved process is disclosed for treating aluminum for memory disk applications and for producing metal plated aluminum memory disks. It has been found that a solution prepared from methane sulfonic acid and sodium peroxydisulfate can be used as a direct replacement for a nitric acid bath in the processing of aluminum substrates for memory disk application. In accordance with the present invention, the methane sulfonic acid/sodium peroxydisulphate solution can be used to deoxidize the aluminum substrate prior to zinc deposition and also to remove the first zinc film in either alkaline or acid double zinc plating processes.

The present invention generally relates to a process of producing magnetic recording media and to products produced thereby. More particularly, the present invention relates to metal plating of zinc plated aluminum and, more specifically, to an improved process of treating a substrate aluminum to provide an exceptional surface condition prior to further plating processes. The present invention is particularly advantageous in both alkaline and acid double zinc plating processes.
Magnetic recording impulse memory devices are extensively used in computer and data processing systems. These devices generally include a substrate on which a thin film of magnetic material has been deposited. The present invention has particular advantageous application to the manufacture of rigid memory disks having large storage capacities.
The requirements of the magnetic recording media of these disks are critical since the reading and writing of information data on the surfaces thereof are usually performed by magnetic transducers which are supported in flying heads positioned in closely spaced relation to the surfaces of the disk. Aluminum is the preferred substrate for the disks although other suitable metals may be employed. In general, a relatively thin layer of nonmagnetic electroless nickel is applied on the aluminum followed by a thin layer of magnetic material such as cobalt. A signal is stored on the disk by magnetizing the cobalt layer to represent the signal at a selected moment in time.
Typical alloys used for memory disks are Aluminum Association Nos. 5086 and 5586. Rigid memory disks have, in the past, commonly been manufactured by initially cleaning the surface of an aluminum disk which renders it receptive to a non-magnetic coating, electrolessly depositing a non-magnetic nickel containing layer thereon, cleaning and activating, or cleaning, activating and mechanically polishing that non-magnetic layer to make it receptive to a magnetic layer, and then depositing a magnetic electroless cobalt containing layer thereon. Thereafter, the disk can be cleaned and a lubricant or other protective coating may be applied over the magnetic layer.
U.S. Pat. No. 4,659,605 discloses a process for producing a high density magnetic storage device such as a rigid memory disk having improved magnetic recording properties and comprising the steps of cleaning the surface of a substrate to provide a substantially oil and oxide free substrate surface, electrodepositing a non-magnetic nickel-phosphorus layer on the substrate and, electrolessly depositing a magnetic cobalt-phosphorus layer consisting essentially of cobalt and phosphorus on the nickel-phosphorus layer wherein the electroless cobalt-phosphorus deposition is conducted in an ammonia-free bath containing a source of cobalt ions, a source of hypophosphite ions, and a complexor constituent which includes conjointly, an effective amount of each of a source of citrate ions and a low molecular weight, bath soluble amino acid. The '605 patent also discloses a process wherein the cleaned substrate is zinc plated prior to the deposition of the non-magnetic nickel-phosphorus layer. The '605 patent further discloses the zinc coated substrate can be subjected to a zinc stripping operation by immersion of the disk in a suitable acid such as, for example, nitric acid, followed by a further zinc plating step.
U.S. Pat. No. 5,141,778 discloses a method of preparing aluminum memory disks using a double zinc plating procedure wherein a nitric acid bath initially consisting essentially of nitric acid and a specified added amount of a Group VIII ion is used to treat the first zinc coated substrate and the zinc coated aluminum substrate is plated using an electroless metal plating bath containing an effective amount of cadmium ions. As noted by the '778 patent, aluminum alloys when exposed to the air rapidly forms an oxide which can present plating problems. As a result, special treatments must be employed when plating on aluminum. These treatments generally include mechanical treatments; chemical etches; alkaline displacement solutions; and anodizing.
Despite the existence of methods for treating aluminum for subsequent plating the need still exists for an improved process of preparing an aluminum substrate for memory disk applications. In this regard, although nitric acid baths have been used to prepare the aluminum substrate for subsequent plating and to remove the first layer of zinc deposited thereon in double zinc plating processes, the presence of nitrate ions has been found in certain applications to limit the effectiveness and degree of depositing zinc upon the substrate. The surface condition of the zinc coated aluminum can affect the surface condition of the non-magnetic nickel layer deposited thereon. The degree of subsequent polishing of the nickel coated layer depends upon the condition of the nickel coat. Accordingly, it is desirable to have the best possible zinc coated aluminum substrate prior to nickel deposition.

Method of preparing substrates for memory disk applications


An automatic document feeder is mounted on a platen cover, which is located on a housing of a manuscript scanning section and movable relative to the housing to have open and shut states. The automatic document feeder is provided with: a manuscript stacker adapted to have manuscripts stacked on it; an outer frame structure having the manuscript stacker movable to attain the open and shut states; and a handle section provided integrally with the outer frame structure and disposed anteriorly to the manuscript stacker. The space between the manuscript stacker and the platen cover serves as a manuscript discharging section. The handle section is formed in a shape so as to avoid narrowing the entrance for inserting a hand into the manuscript discharging section.

1. Field of the Invention
The present invention relates to a manuscript scanner included in a copy machine, an image scanner, a facsimile, etc. and particularly to an automatic document feeder for automatically feeding a manuscript to be scanned.
2. Description of the Related Art
Conventional manuscript scanners for a copy machine, an image scanner, a facsimile machine, etc. have a transparent plate (for example, a glass plate) as a manuscript scanning surface on which a manuscript is placed and scanned, and a platen cover for covering the manuscript scanning section to shut off the ambient light when scanning. There are two ways for placing a manuscript on the transparent plate of the manuscript scanning section: one being for the user to manually and directly place the manuscript on the plate of the manuscript scanning section, the other being for an automatic document feeder to supply the manuscript to the manuscript scanning section. In the former case, it is required to open the platen cover when placing or taking out the manuscript and shut the platen cover when scanning, and in order to meet this requirement, the platen cover is mounted on the housing of the manuscript scanning section so as to allow opening and shutting operations through a hinge mechanism.
The automatic document feeder, in contrast, is commonly constructed to be fitted on the platen cover to avoid an increase in the size and complexity of the manuscript scanner and further to shorten the feed distance of the manuscript to facilitate the feed operation and also simplify the structure. In this case, there is a structure in which a manuscript stacker for stacking manuscripts to be fed is disposed on the platen cover and the manuscripts that have been scanned are discharged on the platen cover.
In the structure in which the automatic document feeder is fitted on the platen cover, the automatic document feeder and platen cover are opened and shut as one unit. As a result, the platen cover fitted with the automatic document feeder is heavy as compared to the structure in which solely a platen cover is opened and shut, entailing difficulty in handling the platen cover unless the user holds it firmly by hand during the opening and shutting operations.
For this reason, there is a structure in which concave portions 22 are formed in platen cover 21 as illustrated in FIG. 1 and FIG. 2 to assist the user to facilitate holding it by hand (cf. Japanese Patent Laid-open No. 2002-152462) and a structure in which a handle is provided (cf. Japanese Patent Laid-open No. 93076/83).
In the case where it is unnecessary to provide a manuscript discharging section on a platen cover, as with the structure described in Japanese Patent Laid-open No. 93076/83, it will suffice to construct the platen cover and manuscript stacker so that they have a sufficient strength. In recent years, however, there has been a main tendency to adopt the structure in which manuscript discharging section 23 is provided on a platen cover 21, as described above, to achieve reduction in size and weight of the platen cover (cf. FIG. 1.) In the structure in which the manuscript stacker 24 is located on the platen cover 21 and the scanned manuscripts are discharged into the space (manuscript discharging section 23) on the platen cover 21, it is necessary for the user to insert a hand into the space between platen cover 21 and manuscript stacker 24 (manuscript discharging section 23) when the manuscript which has been scanned and discharged into the space is taken out. In order to facilitate removal of the manuscript, platen cover 21 has been formed thin as described in Japanese Patent Laid-open No. 2002-152462.
In the above structure, it is difficult to balance competing goals of both providing concave section 22, in platen cover 21, that has large enough dimensions to allow a user to lift it up by inserting a hand into concave section 22 in order to open and shut platen cover 21, and keeping sufficiently large space (manuscript discharging section 23) for the user to remove a manuscript with a hand which is inserted between platen cover 21 and manuscript stacker 24. In other words, concave section 22 is formed to protrude upward toward manuscript stacker 24, which narrows the entrance of manuscript discharging section 23. The position of concave section 22 is set up to the front of platen cover 21 which makes it easy for the user to handle, while the position is also suitable for the user to insert a hand into manuscript discharging section 23. For this reason, if the user inserts a hand into manuscript discharging section 23 from a position away from concave section 22, such operation is troublesome to the user. After all, unless the space between platen cover 21 and manuscript stacker 24 is sufficiently enlarged entailing an increase in the size of the device, it is difficult to attain both goals for facilitating the removal of a discharged manuscript after scanning and facilitating the opening and shutting operations of automatic document feeder 25 and platen cover 21.
If concave section 22 of platen cover 21 is formed in a size and a shape that is hard to handle, or disposed in a position that is hard to handle, as a result of facilitating the removal of a manuscript, the user might possibly perform opening and shutting operation of automatic document feeder 25 and platen cover 21 by grasping any other portion of platen cover 21 other than concave section 22. The user in many cases holds the platen cover 21 particularly while grasping the front portion of manuscript stacker 24. Manuscript stacker 24 itself, however, is in many cases constructed so that it can swing relative to platen cover 21 by means of a hinge structure etc. to enable recovery when manuscript jam (paper jam) occurs in automatic document feeder 25. In this arrangement, manuscript stacker 24 does not have sufficient strength and cannot endure the forces repeatedly exerted through frequent opening and shutting operations, possibly resulting in breakage. In other words, if the attempt to improve the operationality of the manuscript removal operation adversely entails degradation of the operationality for the opening and shutting operation of platen cover 21, then the user will selectively grasp any portion that is easy to hold and do the opening and shutting operation, as described above. This involves the possibility of breakage in manuscript stacker 24 which may not be sufficiently strong.

Automatic document feeder and manuscript scanner provided with platen cover with easily operable handle


A diaphragm for use in a diaphragm-type flush valve includes a flexible diaphragm body having a first side and a second side and an outer periphery, a center passageway defined in the diaphragm body, a bypass orifice defined in the diaphragm body, and a sealing ring attached to the outer periphery of the flexible diaphragm body. The sealing ring defines an outer circumferential surface of the diaphragm. The outer circumferential surface of the sealing ring defines a recessed area. The recessed area is configured to be positioned in a keyed relationship with a flush valve body.

Field of the Invention
The present invention relates to flush valves, and more particularly, to diaphragms used in flush valves.
Description of Related Art
Flush valves in water closets, urinals, and other plumbing devices which utilize a flexible diaphragm to establish and to seal off the connection between the inlet and outlet are well-known in the art. Typically, the diaphragm is made of an elastomeric material, such as rubber, and includes a filter and bypass, which provides fluid communication between the inlet side of the flush valve and an upper chamber of the flush valve. Such flush valve diaphragms are described in U.S. Pat. Nos. 7,516,938 and 8,210,202, which are hereby incorporated by reference in their entirety.
The performance of prior art diaphragm-type flush valves can depend upon how well the diaphragm seals off the connection between the inlet and the outlet. The performance also depends on the pressure drop between the opposite sides of the diaphragm due to the bypass orifice. A diaphragm with a misaligned bypass orifice can prevent water from flowing to the top side of the diaphragm, which results in an inadequate seal. The correct positioning of the bypass orifice within the flush valve is paramount to ensuring that the proper pressure drop is established between the opposite sides of the diaphragm.
Accordingly, there is a general need in the art for a flush valve assembly and flush valve diaphragm that are configured so as to ensure correct positioning of the bypass orifice with respect to the body of the flush valve assembly during installation of the flush valve diaphragm and diaphragm assembly.


A one-piece, seamless food service base is insert molded from a heat and impact resistant plastic. The base is shaped to receive a standard serving plate and includes an integrally molded core. The core is made from a metal or other material that is characteristically susceptible to heating through induction heating. In one form, the core is a solid metal disk with strategically disposed bores for molding the base. In another form, the core is a hollow metal disk having a standard wax phase change core.

Institutional environments such as hospitals and nursing homes, hotels, banquet halls, and the like all have food service operations that require the use of devices to maintain the prepared food warm after its preparation and before service. Generally, the kitchen for these types of places is in a location that is remote from the patients or people and thus the food needs to be transported from the remote location to the patients or people. In many instances the length of time between the preparation of the food and the serving of the food may be upwards to one hour. In some cases, it has been found desirable to prepare the meals well in advance of serving.
Obviously, it is desirable to maintain the heated food warm until it is served. To this end, there have been developed essentially three types of devices for maintaining the food warm from the time of preparation until the time of service. One way is termed rethermalization. In rethermalization the food is placed on plates on a tray, with the tray placed within a metal cabinet. The cabinet includes heating pads for each tray that correspond in location to the food to be heated on the tray. The entire meal is placed on the tray with a plurality of trays stored in the cabinet. The cabinet is stored in a refrigerator unit until it is time to reheat and serve the meal. A heater control coupled to the cabinet and heating pads is activated to heat only the food on the warming pads thereby keeping the remaining food cold. The heating is accomplished while the cabinet is within the refrigerator unit. Once the rethermalization cabinet has been removed from the refrigerator unit, there is no more heating of the food. Therefore, depending on the time out of the refrigerator and the distance to each and the last patient, the food can cool down. Therefore, such cabinets are of limited effectiveness.
Another way is to provide an insulated container, generally consisting of an insulated base or tray with an insulated cover therefore. A plate with heated food is placed on the previously insulated base with the cover placed thereover. The heat from the heated food maintains the food warm within the insulated cover. These devices are effective for generally short periods of time and only moderately effective for longer periods of time.
Yet another type of device in use is a heatable base that is likened to a heat sink. This type of device is effective when all of the food on the plate is to be kept warm. The base is heated to a sufficient temperature whereupon a plate with prepared food is placed upon the heated base and a cover placed thereover. The base is placed in a convection type heating unit or oven to sufficiently heat the base. The core of the base includes what is known as a phase change material that absorbs heat when heated, and which slowly dissipates the heat thereafter. The dissipating heat is transmitted to the plate situated thereon to keep the food warm. Generally, a cover is placed over the plate that mates with the base.
Prior art heatable bases have included such phase change materials as pure wax, solid phase change materials, and bladders carrying such materials. In the prior art these bases have been manufactured from plastic and stainless steel. Such bases are exemplified in the following U.S. Pat. Nos.: 2,876,634 issued Mar. 10, 1959 to Zimmerman et al.; 3,054,395 issued Sep. 18, 1962 to Torino; 3,065,744 issued Nov. 27, 1962 to Scavallo; 3,148,676 issued Sep. 15, 1964 to Truog et al; 3,557,774 issued in 1969 to Kreis; 3,837,330 issued Sep. 24, 1974 to Lanigan et al; 3,875,370 issued Apr. 1, 1975 to Williams; 4,059,096 issued Nov. 22, 1977; 4,086,907 issued May 2, 1978 to Rothschild; 4,246,884 issued Jan. 27, 1981 to Vandas; 4,505,252 issued Mar. 19, 1985 to Wada et al; 4,567,877 issued Feb. 4, 1986 to Sepahpan; 4,777,931 issued Oct. 18, 1988 to Ziegler et al; 4,982,722 issued Jan. 8, 1991 to Wyatt; and 5,125,391 issued Jun. 30, 1992 to Srivastava et al. However, stainless steel is quite objectionable in that stainless steel transfers its heat at a much quicker rate than plastic. Also, all of these bases must be heated by a convection type oven or heating unit which generally takes a fair amount of time to raise the temperature of the core of the base to a sufficient temperature. Furthermore, plastic is air permeable, which over time allows air to penetrate into the phase change material which reduces the life expectancy or use of the phase change material and the base. Also, such high convection temperatures that are necessary to raise the core to a proper temperature for maintenance of a specific low end or minimum temperature for a specific period of time anneals the plastic causing the plastic to become brittle and fail.
It is apparent from the foregoing that the prior art food warmers are deficient in many respects. Thus, it is an object of the present invention to provide a heat retentive base for food plates that reduces the time necessary to sufficiently heat the base.
It is another object of the present invention to provide a food service base whose operation is not affected by time, air permeability, or repeated use cycling.