An apparatus for containing a fluid, said apparatus comprising (d) at least two internal chambers, (f) a fluid product line leading from each chamber to (g) a junction for product lines from at least two of said chambers to produce a mixed product, (h) means for delivering a desired ratio of fluid products in said mixed fluid product, (i) an exit line from said junction for said mixed fluid product, and (j) means for reversibly closing said exit line.

The present invention relates to dispensers for dosing fluids in controlled amounts into other fluids.
In many process operations, it is necessary to dose a specific amount of a particular additive into a large amount of a base fluid, either on a batch or continuous basis. These operations may involve dosing a product with a small amount of additive to stabilise the product or alter its performance. Examples of additives that may be used in such operations include antioxidants, thermal stabilisers, pour point depressants, viscosity modifiers, de-icing additives, octane/cetane boosters and detergents. Examples of products that maybe treated with additives include molten polymers and hydrocarbon fluids, such as crude oil and crude oil derivatives, for example, gasoline and diesel.
It is often difficult to dispense the additive routinely at the correct dosage rate, particularly, when more than one additive is required. The operation is especially difficult when the relative ratio(s) of the dosing rates of the two (or more) additives is important.
The present invention provides a dispenser capable of dispensing at least one, preferably, two or more additives at a substantially constant ratio.
The present invention provides an apparatus for containing a fluid, said apparatus comprising
(a) a wall defining
(b) an interior, which comprises
(c) at least one collapsible partition, which, with said wall, itself or another of said partitions defines
(d) an internal chamber in said interior,
(f) a fluid product line leading from the internal chamber to an exit line, and
(j) means for reversibly closing said exit line.
In a preferred embodiment, the apparatus comprises:
(a) a wall defining
(b) an interior, which comprises
(c) at least one collapsible partition which with said wall or another of said partitions defines
(d) at least two internal chambers in said interior, optionally (e) at least one means allowing transmission of pressure across said wall,
(f) a fluid product line leading from each chamber to
(g) a junction for product lines from at least two of said chambers to produce a mixed product,
(h) means for delivering a desired ratio of fluid products in said mixed fluid product,
(i) an exit line from said junction for said mixed fluid product,
(j) means for reversibly closing said exit line.
In another embodiment, the wall (a) defining the interior (b) and collapsible partition (c) need not be present, so the combination of the invention comprises (d) at least two chambers, (f) a fluid product line, (g) a junction line (g) delivery means (h), exit line (i) and reversible closure means (j). Preferably the combination is supported by a frame (k) at least partly surrounding chambers (d). As an alternative to the frame (k), other support means (l) (eg framework (m)) may be provided under the chambers (d). The framework (m) may take the form of a pallet base, for ease of movement. The other features (f-j) may then be protected or located in the support framework. Features d-j may otherwise be as described herein, apart from those requiring attachment to or bearing upon the container wall. The frame k may be open and may be rectangular for ease of transport and stacking, in particular may have an open frame on the bottom and sides of the chambers in use, but with an open top to allow access and action on the chambers to cause their depression e.g. via a plate and a heavy weight e.g. bricks, or full drums or a standing person.
The apparatus above (also referred to as xe2x80x9ccontainerxe2x80x9d) may not be pressurizable to above 1.1 bar. Alternatively, the container may be so pressurizable, with the wall (a) and the interior (b) being closed, apart from the product line (f), junction (g) and/or exit line (i). Where the container is pressurizable, the wall (a) may be pressure resistant.
The apparatus of the present invention may further include an external chamber for containing the container. The container may have the wall (a), interior (b), partition (c), chambers (d), optional pressure transmission means (e), and product line (f). The external chamber section, on the other hand, may comprise the exit line (i) and the closure means (j).
The apparatus of the present invention is particularly useful for dosing mixed products into a line carrying flowing fluid. When used for such a purpose, the container is preferably pressurizable. Preferably also, the exit line (i) is capable of being brought into fluid communication with the main line.
In a modification of the apparatus described in the preceding paragraph, the main line has a side line in a loop between upstream and downstream locations. The container preferably bridges the loop and main lines. Where a pressure transmission means is employed, it is preferably capable of being in fluid contact with the interior of said main line. The exit preferably leads to the side or main line.
The present invention also provides a method of dispensing at least two fluids into a third fluid, wherein said fluids are separately contained in chambers in a container of the present invention, said method comprising applying pressure to said pressure transmission means (e) causing at least partial collapse of at least one partition and egress of said fluids from said chambers with said product lines, passing said fluids through said lines to meet at said junction, and pass through said exit line into said third fluid.
The container may be of any shape, for example, with sharp or rounded edges. The container may have a rectangular or square cross section. Preferably, the container has convex rounded surfaces on at least some sides, especially on one pair of opposing sides. The container may thus be a sphere or especially a drum having convex sides, and a top and bottom which may be planar or slightly convex meeting the sides at a distinct ridge, or may be completely curved meeting the sides colinearly e.g. with hemispherical ends. Both the inside surface and the external surface may have the shapes described above, but preferably the inside surface does, while the external surface is fitted with at least one external stabiliser, e.g. an outwardly extending circular collar and/or legs on the top and/or bottom to allow it to stand upright; said collar and/or legs preferably extend beyond the outermost part of the curved container wall. Advantageously, the container has the stabilisers present on opposing ends of the container. The pressure transmission means (e) are preferably located inside the area of the top end of the container defined by the collar or legs so is protected at least partly. At least one of junction (g) exit line (i) and closure means (j) are preferably located externally of the container but inside the area of the bottom end of the container defined by the collar or legs.
In a preferred form, the container is not sealed, so is not pressurizable to a pressure above 1.1 bar. In this case the container of the invention has features (a), (b), (c), (d), (f), (g), (h), (i) and (j) means for reversible closing said exit line. Any joints through the container wall, need not be pressure resistant e.g. where lines pass through the container wall; seals are not essential and maybe absent. The description of these features in this specification apply in general to the unsealed containers as well as the sealed ones, unless otherwise mentioned. The mixing of the contents of the chambers and ejection of the product into the exit line is usually under the influence of gravity, though this may be aided as described further below. Preferably the container of the invention has features (a)-(d) inside its wall, especially (a)-(f), and in particular (a)-(g) so that only the one exit line (i) projects outside the container.
The container may be provided with means for indicating the volume of fluid contained in the container. For example, at least part of the container""s wall may be transparent so that the interior of the container is at least partially visible.
The container may be made of metal, e.g. steel or aluminium, or plastics material. Preferred plastics materials include engineering plastics, such as a polyalkene e.g. polypropylene, or polyamide e.g. a nylon or polyester e.g. polyethylene terephthalate. If desired the pressure resistant wall may be made of one of the above materials especially steel and the stabiliser e.g. collar or legs may be made of another e.g. aluminium or nylon.
When the container does not need to have a pressure resistant wall, it is preferably a cylindrical drum e.g. of 100-5001 capacity e.g. 200-2501. The drum usually has a first hole in its curved side, and may also have a second hole in an end face. Preferably the product lines (f) and/or exit line (i) pass through one of those holes especially the first hole, so in use the drum is on its side with the first hole downwards and the internal chambers directly above it. The first hole is preferably closed by means of the cover member as described further below. If desired the second hole can be used to manipulate the correct location of full bags onto the product lines or can be used to activate leverage devices to press on the bag contents. If desired the roles of the first and second holes can be reversed. The drum may also have the first hole in its curved side, but an open end, closable with a lid, which end may also be used for manipulation or leverage, as described above.
The container wall is preferably resistant and impervious to any internal pressure encountered during its use, which may be 1-20 bar, e.g. 2-10 bar. Internal or external reinforcement to the wall maybe provided if required, e.g. in the form of one or more external straps.
The wall defines the interior (b) of the container. Inside there is at least one collapsible partition and at least 2 internal chambers whose contents are incapable of direct fluid communication with each other except via lines (f) and junction (g). There may be 2 or more e.g. 2-4 chambers each defined by a flexible and collapsible wall of an internal container e.g. a bag such as one of plastics material e.g. polyethylene, impervious to the material to be received in it in use. In this case the container of the invention has within wall (a) 2 or more plastics bags, each separate from the other, but each joined to a product line (f) leading to the junction (g). The total volume of the bags when full may be the same as the internal volume of the container of the invention, or may be smaller than this. In the latter case, the space between the flexible walls and the internal wall (a) may if desired itself be used for receiving material when the container is in use; the space is then open to a product line (d) of its own leading to junction (g). In these forms of the container of the invention, the application of pressure at (e) causes the contents of the 2 or more chambers to be expelled into the product lines, either via pressure on the flexible walls of the bags causing the bags to shrink in volume by collapsing in on themselves (i.e. substantially normal to their surface) and/or by pressure directly on the material in the space again causing the expulsion. The internal containers e.g. bags may be discrete from one another and independently movable with respect to each other, or at least one may surround another, e.g. with 2 bags one inside the other. In the latter embodiment there are 2 product lines one from each bag, especially with one line surrounding the other, the contents of the internal bag passing through the centre of the overall product line and the contents of the surrounding bag passing through a product line in an annulus to the internal product line. The same arrangement happens in an alternative embodiment when the internal container for one fluid material is surrounded by the space (to the wall (a)) for receiving a second material, so the space is defined by an annulus surrounding the flexible wall of the first internal container.
The collapsible partition may constitute the whole of the wall of the internal chamber, e.g. as with a plastic bag. But the collapsible partition may only constitute part of said wall, the remainder being part of the wall (a) or part of a rigid wall capable of moving relative to said wall (a), e.g. as in a piston head (as described further below); in this case the collapse may be normal to the partition surface as with the bags or substantially parallel to the surface as in a concertina partition or bellows.
The internal chambers in the optionally pressurisable container may be of a number of relative maximum volumes. Usually they may have relative volumes the same as the relative ratios of the fluids being blended, so that as the fluids are removed, the chambers shrink in volume to the same extent and ultimately both chambers have the same minimum volume, approaching zero. The relative weight ratios of additives in the fluid products going to the junction g may be the same as the relative volumes of fluid products going there, and this is useful when comparable concentrations of the additives and weight ratios of about 1:1 e.g. 0.8-1.2:1 are used. But when only a small weight ratio of additives is wanted e.g. additive A to B, it may be preferably to dilute the additive in lower proportion i.e. A so that the volume ratios of fluid products are more comparable, as this aids more accurate ratio mixing. Thus the weight ratios between 2 additives may be 1:10 to 10:1, but the volume ratios of the corresponding fluid products maybe 1:5 to 5:1, but preferably 2:1 to 1:2.
Each product line (f) is sealingly fitted to each chamber (d) and leads therefrom to junction (g), to allow the contents of chamber (d) to flow to junction (g). The line (f) may be attached to a hole in the partition or may itself pass through said hole into the chamber; either of these approaches may be used to empty the contents of chambers which are discrete internal containers e.g. bags. The line f may simply pass through the wall and into the chamber when the latter is defined by the wall (a) and one or more partitions (c). Thus in the latter case, with a collapsible partition defining a first chamber which is surrounded e.g. annularly by the second wall chamber, the product line for the first chamber may be separate from or inside the product line from the second chamber.
The optional pressure transfer means (e) may constitute a pipe optionally reversibly closable, leading from the outside of the wall (a) through said wall to inside the interior of the container. The internal end of the pipe may be located in a space external of said chambers and defined by the collapsible partition and said wall (a); in this case the chambers are preferably in the form of collapsible bags. The internal end of the pipe may also be located in a space external of said chamber and defined by the wall (a) and a transmission plate, which itself is capable of acting on the collapsible partition defining the bags and the space (which may be annular) between said partition and said wall, said latter space being optionally adapted to receive material in use. The transmission plate may thus be a piston head acting either on the bags alone, or on the bags and on the material surrounding the bags but separated therefrom by the partition. If desired the pressure transfer means (e) may constitute said transmission plate attached to a shaft movable through said wall (a) under the influence of external pressure applied to said shaft or a piston plate attached thereto.
The product lines meet at one or more junction(s) (g). When there are three or more product lines, all may meet at one junction (g) or two or more may meet at a first junction (g) and then the exit line from said first junction (g) may lead to a second junction (g) where one or more other product lines (f) meet it. By this means the products in the lines may be mixed together either directly or step wise. Thus junction (g) may have 2 or more inlets for attachment to product lines (f) and at least one exit line for mixed product. The exit line may also be provided with a junction, which is preferably, provided with a valve. An additional container may be coupled to this junction, such that two containers may be coupled to the same exit line. This may be useful when one container is running low, and the other is still full. When the former is depleted, the valve in the junction may be actuated disconnect the depleted container from the exit line, and connect the full container to the exit line, ensuring that supply of container fluid to the exit line is continuous.
In one embodiment, the apparatus is provided with more than one exit line. For example, each product line may lead to an exit line.
There is also means (h) for delivering the fluid products in the desired ratio, which may be fixed or variable. This means controls the blending ratio. Fixed ratios may be obtained by use of product lines (or inlets to the junction (g)) of defined cross sectional area at their narrowest points. Those areas may themselves be in the desired ratio, especially for use with materials in the container of similar viscosity, or in a ratio such that with materials of defined viscosity, the materials will pass through the lines and inlet in the desired ratio, especially at the usual temperature of use. If desired the product lines (and/or junction (g)) may be insulated to reduce the possibility of effects of changing temperature on viscosity (and hence flow) rate and ratio.
Variable ratios for the amounts of the fluid products may be obtained by use of at least one valve, capable of allowing different flow rates of material through it. There may be a valve on each of 2 or more product lines (f), the position of the valve (i.e. its degree of opening) being capable of being varied to give different overall ratios at the junction (g). As well or alternatively the junction (g) may itself be in the valve, which is a proportioning valve capable of adjustment to allow different flow rates through different inlets.
If desired at least one (and preferably all) product line (f) may incorporate a one way valve to allow egress of material from the internal container but no return of it or other material.
The exit line from the or the last junction (g) in a downstream direction may also incorporate a one way valve to allow movement of mixed product downstream but not allow any return upstream. The exit line also incorporates a reversible closure means e.g. valve to allow separation of the container from the main line, e.g. for removal or refilling, or for circumstances when no addition to the line is required.
The optionally pressurisable container of the invention comprises at least 2 fluid product lines (f), a junction (g) and an exit line (i); these may be in different spatial relation to the container, particularly when the container has at least one external stabiliser, e.g. the collar or legs. The inner walls of the collar or by the inside of the legs, together with part of the outer wall of the container defines an external chamber, whose face opposed to that of the outer container wall may be open to the outside or reversibly closable e.g. with a panel or lid, the external chamber being adapted to allow one or more lines to leave it. This external chamber may contain one or more product lines (f), with the junction (g) and exit line and closure means outside said chamber, or one or more junctions g may be inside said chamber as well and the exit line and closure means may be outside, or the product lines, junction g and at least part of the exit line may be inside and the remainder of the exit line and closure means may be outside. The one way valve on the exit line may be inside or outside the external chamber. Finally if desired lines f and i and junction g and closure means j may all be inside said external chamber. The external chamber is usually non pressurisable.
The product lines (f) and if necessary exit line (i) pass through the container wall, preferably in a sealing fit. Thus the container may have at least one orifice, either one for each line (f) and if necessary line (i), or all the lines may pass through the same orifice. The container wall preferably has a hole therein, through which the line(s) pass. Preferably the line(s) pass through orifice(s) in a cover member removably retained in place to sealingly cover the hole. The cover member may be a plug friction fitted in the hole directly or via a surrounding annular flexible grommet. The cover member may also be retained in the hole by means of an external thread thereon engaging a corresponding internal thread of the container or of a flange defining the hole and mounted on or in the container. The cover member may also be urged towards a cooperating flange defining the hole and mounted on the container, via flexible retaining means e.g. spring clips mounted on the cover member, container or flange, and separated from the flange by a flexible ring e.g. an O ring. The above cover members are preferably plates with orifice(s) therein. Alternatively the cover member may be urged towards a cooperating flange defining the hole and mounted on the container, the member being retained on the container by a threaded cap, either directly or indirectly. In the direct case, the cap is annular, the centre thereof allowing freedom for the lines to pass through and has a dependent, internally threaded rim portion adapted to engage a cooperating externally threaded flange on the container. Flexible sealing means e.g. an O ring or washer may be retained between the cap and cover member or cover member and flange, or both. In the indirect case, the annular cap is as described above but the internally threaded rim engages not the flange but a bi threaded annular insert, via an externally threaded broader portion thereof while an externally threaded narrower portion thereof is adapted to engage the threaded flange. The annular insert may be separated from the cover member by the flexible means e.g. as described above, or may itself have a recess in the axial face of the broader portion adapted to receive that flexible means. In the direct or indirect case the cover member may be as described above but preferably in the latter case the member is in the form of a plug with orifice(s) for the lines through it and preferably of shape adapted to be received inside the annular insert. Thus the plug preferably has a radially extending lip to bear upon the broader portion of the insert and a shank to be received inside the narrower portion of the insert; axially through the shank are the orifices which may be of uniform cross section but are preferably of broader cross section on the outer side distant in use from the container, and of narrower cross section on the inner side nearer in use to the container. The product line and/or exit line may pass through the orifices, or an external product line of one width may be inserted and fixed into the outer orifice(s), and an internal product line of narrower width may be inserted and fixed e.g. threaded into at least one of the internal orifice(s). To at least one of to the internal product lines is attached at least one means defining the internal chamber e.g. a plastic bag.
The junction (g) may be inside the container wall or outside it, but near to it so that the exit line (i) is also near the container wall. To protect it a protection cap e.g. hemispherical or cylindrical cap may be mounted on the container to cover the product lines and junctions and to allow the exit line to project through it; the cap may be a friction fit on appropriate lugs or receiving means e.g. the flange, on the container or may be screw threaded to the container or said receiving means. The protective cap also fits over the cover members as described above.
The apparatus for dosing mixed products to a main line comprises the optionally pressurisable container of the invention joined to said main line by way of the exit line. In this instance there is also preferably provided a source of pressure to act on the pressure transmission means (e) to result in flow of product to junction g and hence the exit line and into the main line, in order to overcome the back pressure in the main line. Preferably however the main line has a side line leading to the pressure transmission means which alone or with a source of extra power results in ejection of the mixed product into the main line; the effect of the side line is more closely to balance the pressures on either side of the lines in the pressurisable container and hence reduce the amount of extra power required. The side line may just extend from the main line to the means (e) to exert the pressure from the main line on it; alternatively the side line may extend in a loop returning to the main line. A spur from the side line passing to said means e, so the pressurisable container bridges the loop.
The exit line (i) usually has a small pump or other means for moving mixed product into the main line, especially a positive displacement pump.
If desired the joint between the exit line and main line may be in a location in the main line of reduced pressure e.g. at or downstream of a constriction in said main line causing suction to help remove fluid from the exit line; thus the exit line may meet the main line at a Venturi constriction.
The products in each internal chamber are fluids, usually liquids, including solutions, such as solutions of additive(s) in one or more miscible solvents, such as water, or lower alcohols esters or ketones. The additive may be any of those mentioned above or others for use in the fluid of the main line. The fluid in the main line is usually a liquid e.g. a water or hydrocarbon based fluid, especially the latter, such as an aviation fuel, such as jet fuel, kerosene or aviation gasoline.
In use, each internal chamber with its contents is located in the interior (b). A portion of the wall of the container is preferably reversibly but sealingly openable e.g. removable to allow insertion of the filled chamber such as a filled bag of fluid product or to allow access to said chamber, depleted of product, in order to refill it. If desired the chambers may be filled externally through the exit and product lines so long as the effect of any one way valves is negated i.e. overridden and valves are present to allow inward movement of fluid completely to each chamber in turn, without simultaneous movement of fluid to another chamber.
The filled internal chambers are joined to their product lines and hence to the junction and exit line, which is in turn joined to the main line. Passage of the fluid in the main line is started and pressure is applied to means (e), whether by fluid in the side line or otherwise e.g. a source of compressed gas such as inert gas (e.g. nitrogen). The pressure causes the partitions to collapse either normally as in collapsing bags or concertina fashion, thereby expelling their contents into their product lines to junction g and hence to exit line and into the main line. The means (h) ensures that the correct ratio of fluid products is fed into the main line. Variations in the pressure in the main line may cause variations in the absolute amount of the fluid products fed, but not their ratio to each other or their ratio to the fluid in the main line. With the use of the side line to the pressurisable container, pressure surges in the main line usually do not cause back flow into the pressurised container, and pressure drops do not cause increases in absolute amount added to the main line. Pressure surges may also be compensated for by connection of a pressure measurement device upstream in the main line to the closure means from the pressurised container, measured variations in pressure acting on the closure means so the latter can act as a variable flow exit valve.
In the cases when the container is not pressurized to eject the contents of the internal chambers, those contents may flow under the influence of gravity, once internal and external closures on the product and exit lines are open (e.g. means (j)), assuming a low enough viscosity of the contents at operating temperature e.g. xe2x88x9220xc2x0 C. to +80xc2x0 C., e.g. 10-50xc2x0 C. If required, a positive displacement or suction pump on the exit line will help remove the contents. However, it is preferable to push the contents out rather than relying solely on gravity or suction. Thus the chambers have a force applied to them, either separately to each chamber e.g. each bag but preferably to both chambers (or more) especially when the chambers extend in the container to a comparable level so a single plate can bear onto both (or more chambers). The force may be applied towards the mixing junction (g) or product lines all the time or only when blended product is required. Thus a weight may be placed on the bearing plate or a spring in compression may be located between the plate and the opposed wall of the container distant from the junction or product lines. Preferably the force is applied when required, but not applied otherwise. Methods of achieving the force include a screw press with threaded hole in the container wall engaging a threaded shaft which bears on the plate or a piston one of whose ends bears on the plate and the other end carries a handle, or a levered arrangement where movement of one end of a lever e.g. depression causes the other end of the lever or preferably an intermediate point in the lever (or rigid arm thereon) to bear on the plate. The bearing plate may be constrained to move in a linear direction normal to the bags by side guides mounted on the container inside wall engaging corresponding lugs on the plate. The side guides extend at least the height of the chambers in the container and when the plate reaches the bottom of the guides and the chambers are empty, this fact can be communicated to outside the drum by means such as the lugs also moving a slot in an external guide, or lugs being visible through a vertical slot in the container wall or via other marker moving with the lugs.
An alternative method of applying a force is to place a full container on top of a container which is being used.
It should be noted that the apparatus may be provided with means for insulating or incubating at least part of the apparatus. For example, the internal chamber of the container may be insulated or incubated against extreme fluctuations in temperature, or kept at a particular temperature range. This may be useful when the apparatus is employed in extreme temperature conditions, for example, extremely low temperatures. Under such conditions, the fluids contained in the containers may become too viscous to be deployed.
The apparatus of the present invention may be used to contain additives, such as fuel or lubricant additives. Examples of such additives include lubricity improvers, flow improvers, thermal stability additives, antioxidants, pour point depressants, viscosity modifiers, de-icing additives, octane/cetane boosters, antifoams, demulsifiers, corrosion inhibitors, drying agents and detergents. Such additives may be added to fuels and lubricants. Suitable fuels include both liquid and gaseous fuels, such as natural gas, liquiefied gas, motor and aviation gasoline, diesel, jet fuel, heavy fuel oil, marine fuel oil and kerosene. Suitable lubricants include those for motor vehicles, aircraft and industrial applications.
Where the containers of the present invention are used to deploy aviation fuel or lubricant additives, they may be stored directly on-board the aircraft, for example, in the wing of an aircraft, and operated remotely, for example, by the pilot from his/her cockpit.


A method for categorization using multiple categories including obtaining multiple uniform resource locators (URLs) associated with the multiple categories, collecting multiple web pages identified by the multiple URLs, generating vocabulary terms based on the multiple web pages, generating an N-gram file including the multiple vocabulary terms, generating multiple classified URLs by labeling the plurality of URLs based on the multiple categories, generating multiple feature vectors by processing the classified URLs and the multiple web pages against the N-gram file, generating a categorization model by applying a machine learning algorithm to the multiple feature vectors, and loading a classifier with the categorization module and the N-gram file.

Categorization is the process in which ideas and objects are recognized, differentiated, and understood. Categorization implies that objects are grouped into categories, usually for some specific purpose. Ideally, a category illuminates a relationship between the subjects and objects of knowledge. Categorization is fundamental in language, prediction, inference, decision making and in all kinds of environmental interaction.

Categorization automation based on category ontology


A system for monitoring and signaling by radio a pressure or a change in pressure in pneumatic tires of wheels on vehicles consists of a receiver unit provided in or on the vehicle to which at least one antenna is associated, and of a unit, arranged in the pneumatic tire, for measuring, evaluating and transmitting tire pressure signals.

The present invention relates to a system having the features specified in the preamble of claim 1. A device of that kind is known from WO 93/08035. The device comprises a wheel-mounted electronic unit which is located within the pneumatic tyre and exposed to the pressure prevailing in the pneumatic tyre. The wheel-mounted electronic unit comprises a battery as current source, a pressure sensor for measuring the pressure prevailing in the pneumatic tyre, an electronic evaluation circuit for evaluating the measured-pressure signals supplied by the pressure sensor, and a sensor that is controlled by the evaluation circuit and by which signals containing information on the pressure in the tyre, derived from the measurement, are transmitted to a receiver unit. The pressure sensor is a semiconductor-based absolute-pressure sensor and supplies an electric output signal corresponding to the respective current tyre pressure. The receiver unit is a detached remote-control unit containing an interrogator by means of which the wheel-mounted electronic unit can be transferred from a current-saving state, in which a receiving means contained in the wheel-mounted electronic unit and an activation unit are kept in a standby state, into its normal operating state. The wheel-mounted electronic unit then measures the pressure and sends out a signal, containing information on the absolute pressure, to the remote control unit, which latter is provided with a liquid-crystal display from which the measured value can be read. A sequencing control takes care of the timely transmission of the pressure signal. The wheel-mounted electronic unit is then returned to its current-saving state, in which it consumes some microamperes of current. A lithium battery with the dimensions of a button cell, having a nominal voltage of approximately 3 V and a capacity of approximately 50 mAh, permits in this way the tyre pressure to be transmitted approximately 200 times only. If a service life of five years is to be achieved, then the pressure can be interrogated once a week only. This is absolutely insufficient, judging by the requirements of the automobile industry. On the one hand, it is desired for the battery to have a service life commensurate with the service life of the vehicle, because exchanging the battery in the wheel-mounted electronic unit is possible either not at all or only at high cost. On the other hand, effective monitoring of the tyre pressure is not possible with an interrogation frequency as low as once per week. A dangerous situation may arise for the driver when a sudden pressure loss occurs which can be detected only if the tyre pressure is measured at intervals of a few seconds. In order for this to be achieved, advanced tyre pressure monitoring systems do not transmit the tyre pressure every time it is measured, but transmit it only when a pressure deviation that may impair the driving safety becomes apparent or, from time to time, when the serviceability of the wheel-mounted electronic unit is internally checked and reported to the receiver unit. (DE 195 22 486 C2; the AMI DODUCO company publication entitled xe2x80x9cElectronic tyre pressure control system. Higher driving safetyxe2x80x94higher comfortxe2x80x9d). This requires that the pressure be not only measured, but also evaluated in the wheel-mounted electronic unit, for which purpose the wheel-mounted electronic unit comprises an evaluation circuit that controls the transmitter of the tyre pressure electronics and causes it to transmit a signal only if necessary, namely when a relevant pressure deviation has been determined or when the serviceability of the wheel-mounted electronic unit is to be reported. AMI DOCUCO GmbH have succeeded in this way, by strictly optimising the operation of the battery-operated wheel-mounted electronic unit, to reduce the latter""s current consumption so effectively that in the meantime the service life of a battery with a charging capacity of 300 mAh is at least seven years, although the wheel-mounted electronic unit measures the pressure every 3 s and transmits a signal every 54 s. The limited service life of the battery nevertheless remained a basic handicap of that tyre pressure monitoring system.
There have been plenty attempts to overcome the dependency of a tyre pressure monitoring system on the service life of a battery in the wheel-mounted electronic unit. There have been suggestions to equip the wheel-mounted electronic unit with mechanoelectric or thermoelectric transducers which would derive energy from the flexing work of the tyre during motion or from the heat developed during this process, convert such energy into electric current and use the latter to feed an accumulator for the operation of the wheel-mounted electronic unit. Such solutions are, however, too costly and do not offer the required reliability and service life under the rough operating conditions in driving operation.
Another suggestion proposes to supply the required energy to the wheel-mounted electronic unit from the outside, by means of a transponder. The current consumption of the wheel-mounted electronic unit is predominantly not due to measuring and transmitting processes, but to the pauses between the measuring processes when the wheel-mounted electronic unit must be kept in a standby state and when an internal clock operates. A tyre pressure monitoring system of this kind is described in the Internet by the SSI company; the website can be visited under. A transponder, or a responder, is a radio system that operates without a current supply of its own, transmits answering signals in response to interrogation signals received, and derives the energy required for this purpose from the very interrogation signals. In the case of the tyre pressure monitoring system, an interrogator, transmitting the interrogation signals, and a responder, receiving the answering signals transmitted by the transponder, are provided in the vehicle for this purpose. The tyre pressure monitoring system from SSI has the interrogator and the responder combined in one transmitter/receiver unit, which in the case of a vehicle with four wheels is connected to four antennas arranged in the wheel wells of the body close to the wheels. The interrogator sends out at regular time intervals an interrogation signal to a transponder included in the wheel-mounted electronic unit, and the transponder activates the wheel-mounted electronic unit, which contains neither a battery nor an accumulator, and transmits to it simultaneously the electric energy required by it to carry out a measuring operation and to transmit the measuring result back to the responder. It is a disadvantage of this system that the wheel-mounted electronic unit with the transponder is arranged, well-shielded, inside the wheel. The wheel rim, a steel belt in the tyre and fillers in the rubber of the tyre attenuate the signals transmitted by the interrogator and by the transponder so heavily that the antennas of the interrogator and of the responder must be arranged in close proximity to each wheel and the power of the interrogator must be sufficiently high to activate the wheel-mounted electronic unit and to make available, in addition, sufficient transmitting power for re-transmitting a tyre pressure signal. This makes that solution so expensive that it has not till now found acceptance in practice.
Now, it is the object of the present invention to open up a way of further increasing the service life of the battery in a battery-operated wheel-mounted electronic unit of a tyre pressure monitoring system without having to reduce the measuring rate for the tyre pressure.
This object is achieved by a system having the features set forth in claim 1. Advantageous further developments of the invention are the subject of the dependent Claims.
The invention combines a system of the known species, which is dependant on a battery, in a non-obvious manner with elements of the system that instead of using a battery works with a transponder, thereby achieving a result that utilises the advantages of the two oppositely directed technical concepts without, however, taking over their disadvantages. The receiver associated to the wheel-mounted electronic unit, which responds to the signals transmitted by the interrogator and which, preferably, is configured as a separate chip module, is not a complete transponder but utilises, essentially, only its receiver component; instead of the radio transmitter employed by a transponder, which is operated by the interrogation signals, the receiver only uses a trigger circuit that triggers and activates the battery-operated wheel-mounted electronic unit. The energy required for operation of the receiver is drawn by the receiver from the radio-frequency interrogation signal but, contrary to the known transponder solution, does not supply the remaining elements of the wheel-mounted electronic unit; rather it only generates trigger signals that activate the wheel-mounted electronic unit so that the latter is caused to perform one or more measuring and evaluation cycles and to transmit a radio signal to the receiver unit if this should be found necessary, based on the measuring results, the energy for the measuring, evaluation and signalling processes being drawn from the battery. After a certain period of time, which may be pre-set by suitably programming the wheel-mounted electronic unit, the electronic unit is deactivated again, unless it is caused to perform further measurements, based on the results of the evaluation of the pressure measurement, in order to verify a pressure drop observed and/or to observe its further development; such further measurements may be carried out according to the criteria, and in the manner disclosed by DE 195 22 486 C2 and the AMI DODUCO publication.
Contrary to a complete transponder solution, the receiver is only used to generate a trigger signal for activating the battery-operated wheel-mounted electronic unit. The energy, that is to be transmitted together with the interrogation signal, can therefore be much lower than the energy required to be supplied to the transponder according to the prior art, as known from SSI, in order to operate the entire wheel-mounted electronic unit and, in addition, to send the radio response signal, with the pressure information contained therein, to the receiver unit. This unusual, restricted use of elements of a transponder operating without a battery, in combination with a battery-operated wheel-mounted electronic unit, provides substantial advantages for the present special application in a tyre pressure monitoring system:
The current consumption of the wheel-mounted electronic unit, in its current-saving state, could be reduced to below 1 xcexcA.
For transmitting the interrogation signals, it is no longer necessary to provide a separate antenna in the wheel well of each wheel. This cuts down considerably the cost of antennas and their installation. Since a separate antenna is no longer needed in each wheel well, it is no longer necessary to run a radio-frequency line into each wheel well. Rather, one or two antennas, which may be arranged in the middle of the vehicle, will be sufficient.
The interrogator may have a considerably lower rated power compared with that of a complete transponder solution (SSI), which helps reduce its cost considerably.
Since the receiver associated to the respective wheel-mounted electronic unit is now intended only to receive the interrogation signal and to convert it into a trigger signal, but is not required to make available the power for the operation of the wheel-mounted electronic unit and its transmitter, the receiver may have a lower power rating than one used in a complete transponder and may, therefore, be cheaper. Low-cost transponders are found today in great number in identification systems (access control) where identity cards are used in which a transponder in the form of a chip module with connected antenna is sealed, which is checked in no-contact fashion by a card reader that contains the interrogator and the responder. As the transponders used for this purpose are produced in large quantities, they are available at low cost. Their reach (distance between transponder and reader) is in the order of one meter and above. Considering, however, that according to the invention the response channel of the transponder is not used, an even greater range can be anticipated for such a transponder, if used in only one transmitting direction, namely from the interrogator to the receiving module of the transponder. Consequently, low-cost transponder modules of the kind employed in no-contact identification systems are also suited for use in connection with the present invention, although only their receiver module is required in this case, with the result that the chip module containing the receiver should also be cheaper compared with a complete transponder chip module.
The receiver associated to the wheel-mounted electronic unit draws no current from the battery of the wheel-mounted electronic unit. As usual with transponders, the receiver in fact does not require any electric current for being kept in a standby state for receiving an interrogation signal.
Given the fact that the wheel-mounted electronic unit is preceded by a receiving circuit which as such does not consume any current, there is no need, contrary to the case of WO/9308035, to keep the wheel-mounted electronic unit in a standby state, so that current consumption is reduced.
The wheel-mounted electronic unit must be kept in a standby state only insofar as it must be possible to activate it through a trigger signal transmitted from the receiver. When the wheel-mounted electronic unit comprises a volatile memory, the latter must be kept at a certain voltage to prevent data losses. This does not, however, result in considerable current consumption.
The internal clock of the wheel-mounted electronic unit, which in the case of the known solution as described by the AMI DODUCO publication and by DE 195 22 486 C2, had to be kept operating in the current-saving state of the wheel-mounted electronic unit in order to be able to activate it at predetermined time intervals, may be switched off in the case of the invention when the wheel-mounted electronic unit is in its current-saving state.
The interrogator can be switched off when the ignition is switched off or the car is locked, and can be switched on when the car is unlocked or the ignition system is switched on. In the inoperative condition of the vehicle, interrogation of the wheel-mounted electronic unit then does not take place, whereby current consumption is once more considerably reduced because most of the cars are in an inoperative state for more than 90% of their service life. Active operation of the wheel-mounted electronic unit is thus limited to the times in which the vehicle is operative. A safety-relevant pressure drop in a tyre, that may have occurred during the inoperative time, is nevertheless detected and signalled. This is achieved, preferably, by an arrangement where the interrogator is switched on simultaneously with the ignition system or when the vehicle is unlocked, whereupon the wheel-mounted electronic units are immediately interrogated and provided an opportunity to report any critical pressure deviation that may have occurred. In this way, the driver is informed of any critical pressure deviation, that may have occurred during the inoperative state of the vehicle, even before the vehicle starts moving. This is an essential safe-relevant aspect of the invention.
Given the fact that in the case of the invention the battery of the wheel-mounted electronic unit is spared very much more as compared with the prior art, it is no longer necessary, when rating the wheel-mounted electronic unit, to pay the same extreme attention to current-saving as necessary heretofore, with a view to achieving long service life of the battery. The circuitry input and the software input for the wheel-mounted electronic unit can therefore be reduced relative to the prior art.
Instead of increasing the service life of the battery, the invention also provides the possibility of reducing the size of the battery and, thus, its cost.
The system according to the invention can be operated so that each interrogation is followed, in the wheel-mounted electronic unit, by a single measuring and evaluation process and, if necessary, transmission of a radio signal. This may take place at intervals of a few seconds. Preferably, however, the system is operated in such a way that after receipt of an interrogation signal, the wheel-mounted electronic unit will not perform a single pressure measurement only, but repeat the pressure measurement and evaluation at regular intervals of a few seconds over a longer period of time of, for example, some minutes and will then automatically return to its current-saving state, as provided for by the programming of the wheel-mounted electronic unit. For example, an interrogation signal could be sent every five minutes to activate the wheel-mounted electronic unit for an active phase somewhat shorter than five minutes. This would ensure that on the one hand the tyre pressure would be continuously monitored in driving operation and that, on the other hand, when the vehicle has been stopped, the wheel-mounted electronic unit would in any case return to its current-saving state at the end of a certain after-running period, and remain in that state until the vehicle is unlocked again and/or the ignition is switched on again.
The radio signals transmitted by the wheel-mounted electronic unit contain several parts in digital form, namely a preamble, the identifier, a tyre pressure signal and a postamble. The radio signals are radio-frequency signals. Radio-frequency transmission is effected in Germany, preferably, in the 433 MHz range, known as ISM band, in certain other countries in the 315 MHz range or the 868 MHz range. The radio signals transmitted by the wheel-mounted electronic units are received by the receiving antennas provided for this purpose.
If a separate receiving antenna is associated to each wheel antenna, the antenna is preferably located in the neighbourhood of the respective wheel, especially on the wall of the wheel well of the vehicle body. There is also the possibility to provide a common first antenna for the front wheels and a common second antenna for the rear wheels, in which case the antennas are preferably arranged approximately midway between the wheels. The receiving antennas transmit the RF signals via special RF lines to the central receiving, evaluation and control unit where a RF receiver, provided with a separate receiving channel for each antenna, amplifies and demodulates the signal received at the input of the respective channel. The low-frequency signal present after demodulation is decoded and evaluated in order to let the driver have a warning, if necessary, or some other information regarding tyre pressure, via the control module of the unit.
The radio signals are weak, with a view to saving current. Due to the low signal level on the electric lines between the receiving antennas and the central receiving, evaluation and control unit, complex measures are required for the electric lines to protect the transmitted signals from external interfering influences. In the case of a practical embodiment of a tyre pressure monitoring system according to DE 195 18 806 A1, the electric lines are costly shielded twisted-pair cables.
According to a further development of the invention, it is therefore preferably provided to associate to each receiving antenna a single-channel RF receiver with demodulator so that the electric lines transmit LF signals instead of RF signals. The LF signals do not require costly shielded cables for their transmission; instead unshielded electric lines may be used which are much less costly. And there is also the advantage that the LF signals formed directly at the antenna are much less susceptible to interference than the RF signals transmitted via twisted-pair cables according to the invention. More details in this respect are disclosed in DE 19 56 898 A1 to which reference is expressly made. Preferably, the receiving antennas of the receiver unit are simultaneously used as transmitting antennas of the interrogator. Advantageously, each antenna may be combined with an interrogator of its own, so that there is no need to run an RF line for interrogation purposes.
The period of time, for which the wheel-mounted electronic unit remains active after having been triggered, not only can be firmly predetermined by suitable programming, but can be selected to be variable in response to one or more physical states, which are variable in driving operation and which are measured in the tyre. Such a state may, for example, be the speed of the vehicle which may be determined by a centrifugal sensor additionally provided in the wheel-mounted electronic unit. During low-risk driving states (slow motion and stopped condition) the time intervals at which the wheel-mounted electronic unit sends out radio signals may be much longer than during high-speed conditions. The measuring rate and the transmitting rate may also be selected to be variable in response to the measured pressure or its variation over time, the rule being that the pressure is measured, and signals are transmitted at higher frequency when the pressure drop rises and develops more quickly. This means on the other hand that in the presence of normal pressure and during a merely slow pressure change the measuring and transmission rates can be extended compared with the prior art. This on the one hand helps save current and permits the frequency of the interrogation signals to be reduced as well. More details about how the measuring and transmission rate can be varied in response to one or more physical states, that vary in driving operation and that are measured in the tyre, are disclosed by DE 198 56 860 A1, to which reference is expressly made.
Generally, the transmission power of the interrogator and of the wheel-mounted electronic unit are sufficient to cover the needs of the four wheels of a vehicle using a common central antenna for radio transmission of the interrogation signals and for receiving the pressure signals. However, there may be the further requirement, as a marginal condition, that the receiver unit be capable of detecting, from the signals emitted by the wheel-mounted electronic units, the actual location in the vehicle of the wheel from which a signal has been received. DE 198 56 861 A1 discloses ways of deriving clear conclusions regarding the wheel position with the aid of acceleration sensors in the wheel-mounted electronic units even in cases where instead of having a separate antenna arranged in each wheel well, next to each wheel, only two antennas, or even a single antenna is provided.
Different operating conditions in which the system according to the invention may assume its active state have been disclosed in DE 195 22 486 C2 and will be described hereafter once more:
1. Original State
Tyre pressure is at its nominal value po, and is constant. This is the condition prevailing at the start of motion and when the vehicle moves at slow speed. The tyre pressure is measured, and compared with the preceding measured value, at regular intervals to. So long as no variation between the two values is detected, no data need to be transmitted from the wheel-mounted electronic unit to the receiver unit. Even small differences between the two pressure values, due for example to the acquisition of the measured values or temperature changes, do not lead to the transmission of data to the receiver unit as long as the differences do not exceed a threshold value ?p0. The pressure value last measured is stored instead of the value measured before, in order to be compared with the next measured value. Instead of the pressure value measured last, it is also possible to use the mean value of several pressure values measured before, for comparison with the current pressure value.
Irrespective of whether the threshold value has been exceeded or not, a complete data telegram, containing the current pressure value, is transmitted by the transmitter in the wheel-mounted electronic unit to the receiver unit at regular time intervals T0 greater than t0. Such transmission, effected at regular greater time intervals, serves system monitoring purposes and makes it possible to determine the development of a possible gradual drift of the tyre pressure.
Typical numerical values are:
t0: 1 to 10 seconds;
T0: 0.5 to 60 minutes;
?p0: 10 to 100 mbar (103 to 104 N/m2)
2. Motion without Pressure Drop
At the start of motion, the tyre pressure has the initial value p0. The normal flexion encountered during motion has the effect to heat up the tyre and, thus, the air in the tyre, a lesser or higher degree, depending on the speed. This causes the pressure in the tyre to rise so that the current tyre pressure comes to exceed the initial pressure p0 and to vary in response to the driving speed and the properties of the road. The resulting variation of the tyre pressure develops so slowly that the pressure variation does not reach the threshold value ?p0 in the time intervals t0 so that the transmitter will not be activated. Nevertheless, information regarding the pressure prevailing in the tyre is transmitted to the receiver unit at the time intervals T0, together with the data telegram which also serves system-monitoring functions. The information regarding the absolute tyre pressure contained in the data telegram is used by a processor provided in the receiver unit to detect and evaluate slow pressure variations in all tyres of the vehicle, especially in the tyres on a common axis, and to thereby identify pressure variations resulting from normal flexion work.
3. Motion with Slow Pressure Drop
Slow pressure drop is determined in the same way as slow pressure changes during motion without pressure drop. A slow pressure drop is identified by the processor in the receiver unit based on the absolute pressure values and on a comparison between the measured pressure values of the different tyres.
4. Rapid Pressure Drop
In the case of a rapid pressure drop, caused by damage to the tyre or to the valve, the pressure drift becomes so considerable that the pressure change between the comparison pressure signal formed last and the current pressure signal comes to exceed the predetermined threshold value. In this case, a signal indicative of the pressure drop could be transmitted to the receiver unit immediately. However, in order to exclude any accidental faulty measurement, a signal, preferably, is not sent to the receiver unit immediately after the threshold value has been exceeded; rather, the measuring rate is first increased, i.e. the time intervals are reduced for a predetermined number of measurements from t0 to t1 less than t0, especially to values of t1 of between 1 to 100 milliseconds. If the fact that the threshold value has been exceeded is confirmed by the next measurements, preferably by the next two to ten measurements, then the transmitter is activated and the pressure signal is transmitted to the receiver unit. Regarding the measurements performed at the higher rate it must of course be considered that the threshold value must be correspondingly reduced for the shorter time intervals, for the same speed of pressure drop. In view of the limited sensitivity of the pressure sensor, this will, generally, not be possible to the extent necessary. It is therefore preferable in this case to continue to use as comparison pressure signal the comparison pressure signal formed last before the time interval was reduced from t0 to t1 until the predetermined number of measurements with the higher measuring rate is completed or the measuring rate has been extended again to its original value (time interval t0).
A different solution is the possibility to send a pressure signal at a higher measuring rate (time interval t1) every time the measured pressure value has changed by a given amount, for example by 10 to 100 mbar. If a further pressure change is no longer detected (pressure change smaller than the threshold value ?p0), then either measurements are continued for a certain time at the higher measuring rate (time interval t1), or a predetermined further number of measured values are picked up at the higher measuring rate (time interval t1), whereafter the system is returned to the original lower measuring rate (time interval t0).
The system may be switched back to the lower measuring rate also when the measured pressure value exceeds a predetermined maximum value of, for example, 5 bar or drops below a predetermined minimum value of, for example, 1 bar. When the measured pressure values drop or rise significantly, the system is then again switched to the higher measuring rate.
5. Filling Operation
During filling, the pressure varies so rapidly that the threshold value (between 10 and 100 mbar) is regularly exceeded at the normal measuring rate (time intervals t0 between 1 and 10 seconds). It is, therefore, possible to proceed in the same way as in the case of rapid pressure losses. However, as generally the filling operation is not critical, there is also the possibility to transmit a pressure measuring signal only after the tyre pressure has stabilised again, which indicates that filling has been completed.
6. Theft Control
If the central receiver unit is not completely switched off in times when the vehicle is stationary, but is switched off only at intervals or is switched over to a lower interrogation rate of, for example, one interrogation cycle in 5 to 10 minutes, then the tyre pressure monitoring system can be used also for monitoring the vehicle wheels as an anti-theft measure. The wheel-mounted electronic units will then from time to time send out a data telegram, containing information on the vehicle state, to the central receiver unit in the vehicle also in the stationary condition of the vehicle. When a wheel is stolen, no data telegram is received, and this is discovered by the evaluation circuit in the central evaluation unit and may be answered by an alarm.
Since the wheel-mounted electronic unit is intended for measuring the pressure in the tyre, it is arranged in the tyre. This can be achieved by positioning it on the valve base, as described in WO 93/08035. Or else it may be arranged in the area of the wheel rim enclosed by the tyre. Where wheels are provided with a plastic ring, intended for stabilising the tyre in an emergency situation after a pressure drop and arranged in the air chamber of the tyre for the purpose of maintaining emergency running conditions when mounted on the rim, the wheel-mounted electronic unit may be arranged also in a recess of that plastic ring.

System for monitoring and for signaling by radio the pressure in pneumatic tires on motor vehicles


A tree stand includes a standing section with attachment members, a releasable standing section lashing member attachable to the standing section attachment members, a seating section including seating section attachment members having upper and lower surfaces, and a plurality of spaced holes extending between the upper and lower surfaces, and a seating section lashing member having first and second ends with handles positionable on the upper surfaces of the seating section attachment members, the handles including projections releasibly attachable in selected holes in the seating section attachment members. The tree stand may also include at least one adjustable tie-down strap attachable between the standing section outer end and the standing section inner end, and tree grippers with spaced, parallel trunk-contacting blades attached to the inner ends of the standing and seating sections.

(1) Field of the Invention
The present invention relates generally to a tree stand of the type used by hunters to ascend a tree and provide an elevated seat thereon, and in particular to a tree stand that can be adjusted as the hunter ascends or descends the tree to provide a level and secure platform.
(2) Description of the Prior Art
Tree stands used to provide an elevated seat for hunters are well known in the prior art. One type of stand, known as a climbing tree stand, is constructed of a seating section and a standing section. The sections are attached to a tree with the seating section being above the standing section. The hunter then raises the sections in an alternating fashion to elevate the stand to the desired height on the tree.
Stand sections are releasibly secured to the tree by flexible attaching members that extend around the tree from one side of the stand section to the other side. U.S. Pat. Nos. 6,182,792; 5,234,076 and 5,097,925 are all examples of climbing tree stands using flexible cables as attaching members. While cable has various advantages over other attaching means, these prior art disclosures require insertion of one or both ends of a support cable into relatively narrow support arm tubes, and then inserting a pin through a hole in the side of the tube and a hole in the end of the cable in order to secure the cable in place. Threading a cable inside a narrow tube while at the same time attempting to locate a cable attachment point is cumbersome in daylight, and nearly impossible at night.
Commonly assigned U.S. Pat. No. 6,523,642, issued Feb. 25, 2003, incorporated herein by reference, describes a climbing tree stand constructed to enable the hunter to quickly attach a cable to the tree stand section without having to thread the cable into a tube. Generally, each frame section of the tree stand described in that application includes cable attachment members on each side of the frame, and a cable that is extendable around the tree trunk from one attachment member to the other and releasibly attachable to one of the attachment members by a unique attachment means.
At least one of the attachment members, preferably both attachment members, includes an exterior side with a plurality of first mating elements adapted to mate with a corresponding second mating element adjacent one end of the lashing member. The mating element on the attachment member on the cable is in the form of a projection, while the other mating element is a recess or hole, with the projection element being removably insertable into the recess. The projection element is moveable within the recess from an insertion position to a locked position when said cable is tensioned. In the locked position, the projection is prevented from being removed from the attachment member. Preferably, the attachment members described in that application have outer and inner walls, the recesses are holes, and the projection includes a flange, cap or other component that abuts the inner wall of the attachment member when the projection is in the locked position.
While the attachment mechanism described in U.S. Pat. No. 6,523,642 is a significant improvement over prior art stands requiring insertion of a cable end into a tube, alignment of the cable with the attachment members can sometimes be difficult. Furthermore, the cable may not be held outwardly from the tree trunk as needed for optimum stability. Thus, there is still a need for further improvements to facilitate attachment of adjustable cables to tree stand sections.
Additionally, there is still a need to increase the stability of climbing tree stands, and in particular the movement of the seat section of tree stands once the tree stand has been secured to the tree and is being used by the hunter. Also, there is a need for a means for reliably securing tree stand sections to a tree without significant damage to the tree.
The present invention is directed to a hunting tree stand that is constructed to address these needs. Generally, the tree stand of the present invention, like the tree stand described in U.S. Pat. No. 6,523,642 and prior art tree stands, is comprised of a standing section and a seating section. The standing section includes a frame with an inner end and an outer end connected by side members, and a platform supported on the frame. A tree gripper or gripping section extending inwardly from the inner end of the frame. The seating section is similarly constructed with a frame having inner and outer ends connected by side members, and a tree gripping section extending inwardly from the inner end of the frame. Instead of a standing platform, the seating section includes a seat, which may be fixed or moveable, supported by the frame.
Like the tree stand in Ser. No. 09/947,254, each frame section of the present tree stand includes support or attachment members on each side of the frame, and a cable or other lashing member that is extendable around the tree trunk from one attachment member to the other, and releasibly attachable to one of the attachment members by a unique attachment means. At least one of the attachment members, preferably both attachment members, includes an exterior side, e.g., the top side or outer side, with a plurality of first mating elements adapted to mate with a corresponding second mating element adjacent one end of the lashing member.
As used herein, the term xe2x80x9clashing memberxe2x80x9d is intended to include elongated flexible, straps or bands that are of a sufficient length to extend around an average tree from one side of attachment member to the other. Exemplary lashing members include cables, cords, ropes, woven straps, etc. Preferably, the lashing member is a twisted wire cable with a smooth sleeve, such as a wear-resistant plastic sleeve.
One of the mating elements is in the form of a projection, while the other mating element is a recess, the term including a hole, with the projection element being removably insertable into the recess. The projection element is moveable within the recess from an insertion position to a locked position when said cable is tensioned. In the locked position, the projection is prevented from being removed from the attachment member. Preferably, the attachment member has outer and inner walls, the recesses are holes, and the projection includes a flange, cap or other component that abuts the inner wall of the attachment member when the projection is in the locked position.
Normally, the attachment members will be attached on either side of each frame. The attachment member may be inclined towards the inner end of the standing section frame. The attachment member may be a rectangular tube with four sides, each side having an exterior and an interior surface. Preferably, the attachment member is a solid bar with upper and lower surfaces. The attachment member preferably includes a plurality of equidistant mating elements extending axially along the upper surface of the attachment member.
In a preferred embodiment, each attachment member is an inclined solid bar with upper and lower surfaces, and a plurality of axially aligned holes extending between the bar upper and lower surfaces. The lashing member is a cable with an attachment handle at each end. Each attachment handle includes at least one projection that is insertable into a hole in the attachment member, with the projection being moveable within the hole between an insertion position and a locked position when the cable is tensioned.
The projection may include a distal end with flange or cap adapted to engage the inner surface of the attachment member when the projection is in the locked position. Preferably, each of the holes has an insertion end of a first given width and a locking end of a second given width, and the projection includes an end cap with a third given width, with the third given width being less than said first given width and greater than said second given width, whereby the end cap prevents removal of the projection from the hole when the projection is in the locked end of the hole.
In order to hold the projection in the locked position during use of the tree stand, even if the tension on the cable is temporarily relieved, such as when the stand is being moved to a different position on the tree, each attachment handle preferably also includes a latch member to hold the projection in the locked position, with the attachment member including a latch recess, such as a latch hole, to receive the latch member. The latch member may be a retractable latch pin having an inner end for insertion into the recess, and an outer end with a gripping element to manipulate the latch pin. The latch pin may include an extended position and a retracted position, with a spring to urge the latch member to its extended position and hold the latch in the recess during use. Alternatively, the pin may be threaded, so that it is inserted and retracted by rotating the pin. For example, the pin can be rotated clockwise to the extended, locked position, and rotated counterclockwise to the retracted, unlocked position.
To minimize the projection of the attachment handle and cable from the attachment member, and thereby reduce the risk of snagging, the outer surface of the attachment member may include an axially aligned trough, e.g., a semi-circular trough, to receive the attachment handle and the cable. For example, the trough may be on the upper side of the attachment member with the holes in the bottom of the trough.
The above construction is further modified in the present invention by the inclusion of a cable guide at the inner end of each attachment member to which the cable is releasably attached. Each guide is preferably a C-shaped guide with an open side for receiving the cable. The guide opening preferably extends outwardly from the attachment member so that the cable-receiving interior of the guide is aligned with the attachment member. The opening into the guide is preferably approximately equal to the diameter of the cable. While the open side of the guide may extend upwardly, the open side preferably extends to the side of the stand, with the attachment side or cable-receiving trough of the attachment member extending upwardly.
The tree stand of the present invention also includes adjustable tie-down straps to hold the stand sections, and in particular the seat section firmly against the tree trunk when in use. Climbing tree stands that include safety straps are well known in the prior art. Basically, safety straps are attached between the seating and standing sections of a tree stand, and prevent the seating section of the stand from accidentally falling or slipping beyond the hunter""s reach during climbing, thereby stranding the hunter up the tree. Safety straps, often made of woven nylon belting are securely attached at their upper and lower ends to the inner ends of the seating and standing sections, respectively. If the standing section slips downward, its descent is stopped by the strap, which can be used to pull the standing section back up the trunk.
In the present invention, the safety straps are attached at a different location and in a different way from prior art safety straps, and provide the additional function of holding the sections securely in position once the sections are at the desired height on the trunk. More specifically, the present tree stand includes two safety straps, one on either side of the stand. The lower end of each strap is secured to the standing section, preferably at the standing section inner end. For example, the lower ends of the straps can be attached to the C-shaped guides at the inner ends of the attachment arms.
The upper end of each safety strap is adjustably attached to the seating section at a point spaced from the seating section inner end. Preferably, the upper end of the safety strap is adjustably attached at one side of the seating section between the seating section midpoint and outer end by a buckle through which the strap can slide. Each buckle includes a strap insertion opening and a releasable latching member to lock the strap when the strap is inserted to the desired extent.
The tree stand of the present invention further includes uniquely configured tree grippers that provide improved stability to the stand sections while minimizing damage to the tree trunk. Most prior art tree stands include inwardly extending V-shaped grippers with outwardly extending arms that are held against the tree trunk. The inner, tree-engaging faces of prior art gripper arms normally include a single row of teeth with points or tips that are pressed into the tree trunk, which can damage the tree. In addition, the teeth can slip when the hunter""s weight is placed onto the stand section.
Surprisingly, it has been found that the stand sections can be held more securely against the tree trunk, and the damage to the tree can be minimized with grippers that have inner tree-engaging faces that are comprised of a pair of spaced, parallel trunk-contacting projections or blades. While the blades may include inwardly extending protrusions, the tips of the protrusions may be blunted to minimize damage, since the gripping effect is achieved primarily by the parallel blades. Thus, the tree stand sections of the present invention preferably includes V-shaped grippers with outwardly extending arms, each of the arms having a pair of spaced, inwardly extending parallel blades to engage the tree trunk. These blades may include a plurality of projections. However, the projections can be blunted projections instead of tipped and still provide secure gripping.
In operation, a climber places the tree grippers of the standing section against a tree trunk and loops the standing section cable around the tree trunk. Usually, one end of the cable is already attached to the inner end of one attachment member. The climber positions the cable within the cable guide at the end of the attachment member and tensions the cable by pulling on a handle on the unsecured end of the cable.
Next, a first mating member on the unattached attachment member is selected such that when mated with a second mating member on the handle, the cable remains under tension. A plurality of first mating members on the attachment member generally takes the form of holes. The second mating members or member on the handle generally take the form of a projection or flanged stud.
Next, the climber inserts the handle projection into the insertion end of the selected hole. In order to lock the attachment handle to the attachment member, the climber moves the handle projection within the hole from the insertion end to the locked end. In a preferred embodiment the climber further secures the cable to the attachment member by releasing a spring-urged pin, or rotating a threaded latch pin, to extend the pin into a latch recess while the handle projection is in the locked position. This action latches the cable to the attachment member even in the event that the tension on the cable is relaxed. At this point the standing section is capable of supporting the climber""s weight and can safely be stood upon.
Next, the climber places the seating section waist high and directly above the standing section making sure that the seating section tree gripping section is engaging the tree trunk. As with the standing section, one end of the cable normally is already attached to the inner end of one of the seating section attachment arms. Similar to the procedure described for the standing section, the climber loops or extends the free end of the seating section cable around the tree trunk and through the cable guide at the end of the attachment member. The climber then tensions the cable by pulling on a handle terminating the unsecured end of the cable. To hold the tension the climber selects the appropriate hole on the remaining attachment member, positions the handle projection within the insertion point of the hole and then moves the handle projection to the locked position. In order to further secure the cable to the attachment member the climber releases a spring-urged or threaded latch pin into a latch recess. The seating section is now ready to safely hold the climber""s full weight.
To ascend the tree, the climber places his or her feet in a restraint extending across the standing section platform. The climber then rests his or her weight on the seat of the seating section while using his or her feet and legs to pull the standing section upward. The climber then stands and, using his or her hands, raises the seating section to a waist high position. The climber then sits and again raises the standing section with his or her feet and legs. The two stand sections are attached to each other by at least one, and preferably two, safety straps that are extended to the full length.
When the climber reaches the desired position on the tree trunk, he or she pulls on the upper end of each safety strap to shorten the strap. Since the upper ends of each safety strap extends through a buckle positioned on the side of the seating section frame, tightening of the safety straps urges the rear of the seating section downwardly, pushing the seating section tree gripper firmly against the tree trunk and preventing the seating section from movement. Preferably, one safety strap is positioned on each side of the stand section with the buckles located approximately midway between the inner and outer ends of the stand section.


An improved formulation for repairing breaks and fractures in the plastic inside lining of refrigerators, freezers, and the like, and the method for effecting such repair with the formulation.

In the industry of refrigeration and freezer repair and servicing, one of the most difficult repairs to make is that of mending and restoring the inner wall of refrigerators and freezers which have become cracked, fractured or perforated.
The inside walls of a refrigerator or freezer are commonly made of hardened polystyrene plastics of comparably thin cross-section. Between this inside wall and the outside surface of the refrigerator are placed various insulating materials. However, the thin, polystyrene plastic is frequently cracked or fractured in the course of usage so as to produce an open crack, fissure or hole creating an avenue for moisture from the various foods inside the refrigerator to pass, so as to permeate into the cavity where the insulation is located. After a period of time, the insulation can become so saturated with moisture that the insulating properties are reduced to the point that the refrigeration system runs constantly without maintaining a sufficiently low temperature to preserve the food contents. Invariably, mold and undesirable bacteria develop so as to create an unhealthy invironment for the storage of foods.
A number of methods for repairing these liners have been employed in the past, including tapes, resin, patch kits, and the like. However, these systems create a poor bond with the base material so that areas of non-adhesion or embrittlement occur, or shrinkage arise, or other problems develop allowing avenues for cold air and moisture to reach the insulation cavity. As a consequence, the aforementioned undesirable bacteria build-up and deteriorating insulating properties eventually re-occur. Moreover, the patching systems used in the past have resulted in obvious patchwork that is not esthetically appealing.
The formulation and process of the present invention, however, provide an esthetic, as well as a structurally sound repair that is comparatively simple to perform. The resulting patch frequently produces a repaired area which has strength substantially greater than the surrounding base material. Due to the ease with which the formulation can be pigmented to the desired color, a patch can be made that is extremely difficult to detect.
The present invention relies on the use of a specially formulated liquid coating medium which is applied to the crack in several stages, and incorporates at one point a fiberglass surface matting. The basic ingredients of the coating medium are polystyrene and methyl ethyl ketone. A preferred embodiment of this formulation employs polystyrene granules with sufficient methyl ethyl ketone added thereto to produce a coating medium which is readily applied by the desired coating system. As a general rule, a paint brush works quite effectively for applying the formulation. It has been found that in blending a batch of the coating medium, approximately 1.5 parts by volume of polystyrene granules may be added to approximately 2 parts by volume of methyl ethyl ketone to produce a liquid of the viscosity that can be readily painted onto a surface.
If the refrigerator has a white polystyrene liner, the last coating of material should be appropriately tinted to produce a matching white. It has been found that a generally suitable matching white can be made by adding approximately one-half teaspoon of titanium dioxide to three gallons of the specially formulated coating medium, described above. If volume measuring is not convenient, then a by-weight approach to pigmentation may be accomplished by adding approximately one pound of titanium dioxide to every 50 pounds of polystyrene pellets employed in the formulation of the coating medium. Moreover, the exact amount of tinting can be allowed to vary considerably to permit coloration to the desired degree without detracting from the strength and adhesive properties of the coating formulation. In order to repair a crack or hole in the hard polystyrene liner of the refrigerator, the area in the immediate vicinity of the crack is repaired by first cleaning it carefully and then sanding it lightly. The aforesaid coating formulation of methyl ethyl ketone and polystyrene is then applied over the crack and to the area in the vicinity of the crack by means of a brush or other appropriate means. The coating is then allowed to dry in the air, and once it has hardened, the area is then sanded again. This first coating is normally a clear coating without containing any pigmentation and gives the operator a clear indication is what coverage is being effected by the coating. A second coating likewise of a clear formulation is then applied over the area. While the second coating is still wet, a pre-cut patch of fiberglass surface matting is placed over the coated area. The patched area is then again allowed to air dry until it is sufficiently hard to permit sanding to smooth the surface. At this point, a third coating of the aforesaid formulation is applied to the patched area. Although this last coating may be of a clear formulation, it is usually desired to add the pigmented coating at this stage, and upon air drying, results in an attractive, strong repair.
It has been found that where the fissure in the hard polystyrene liner of the refrigerator or freezer is a crack that a bevelling tool, such as the point of a soft drink can opener, can be run along the crack so as to remove base material and force the edges downwardly towards the insulation. This results in a slight trough which will allow an extra buildup of the coating medium, thereby increasing the thickness of the refrigerator liner at that point. This reinforcing structure will appear along the back side and will not cause any apparent increase in thickness, although the liner is substantially thickened at that point to increase its strength to a point greater than that of the base material. Consequently, the resulting repair invariably does result in a patched area which is of greater strength than the original material.
In addition to effecting repairs after a crack has been created, one can likewise build up the thickness of an area where heavy loads or continued usage is likely to eventually result in a perforation or crack in the liner. In view of the practice in industry to continue to decrease the thickness of the liner, this ability to build up the thickness to a desired level in specified areas, it is of considerable advantage.
When the repair is effected, the foods are always removed from the refrigeration unit so as to avoid contamination by the coating medium. Normally, the repair is effected while the refrigerator is turned off, however, it has been found that in those cases where there is some refrigerator odor that leaving the refrigerator on during repair and closing the door during at least one of the drying stages, will dramatically reduce the undesirable refrigerator odors. Although various fiberglass mattings can be employed, a preferred matting is one which has a normal weave which is slightly coarser than that of cheese cloth. This usually results in openings of approximately 1/32 of an inch, however, openings of other size can be employed without detracting from the desired results. The polystyrene granules or pellets should be of the high impact or medium impact grade. Either the common grade or virgin grade material can be used.
The aforesaid coating formulation can be packages in a number of ways for individual home repair purposes. For example, it can be packaged to include a small vial of the liquid formulation, along with the fiberglass matting, and brushes or spatulas for application. Small pellets for adding to the formulation to produce various pigmentations can be also included so as to produce a match of the repair to the color of the liner in the refrigeration unit being repaired. It is also possible that a repair kit can be made up to include the formulation in a paste or rod form or even in an aerosol or spray can arrangement.
Although the term "fracture" or "fractured" as used herein has been used in connection with fissures, tears, cracks and the like, the term is also intended to cover larger discontinuities such as perforations and large holes. To repair a large hole the first coating of the mixture is applied to the perimeter of the hole and the fiberglass matting is precut to cover the hole for application after the second coating is applied. Although refrigeration units are readily repaired by this system, it can be used in connection with the repair of other polystyrene articles such as television cases, clock casings, toys and the like.
Although there has been shown and described above the particular embodiments of this invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention. Accordingly, certain modifications and alterations will occur to those skilled in the art that are included within the scope of the following claims.

Repair of polystyrene refrigerator liners


Systems may methods may be provided for determining turbulent mixing characteristics. The systems and methods may include obtaining sounding data associated with an atmospheric column and determining first vertical potential temperature profiles from the sounding data. The systems and methods may further include determining second vertical profiles of displacement scales based at least in part on the first vertical potential temperature profiles, and determining turbulent mixing characteristics in the atmospheric column based at least in part on the displacement scales.

Mixing in the free atmosphere above the atmospheric boundary layer (ABL) and the deep ocean below the oceanic mixed layer (OML) has been a tough problem to solve since it is episodic and hard to model using second moment closure. The generation mechanisms in these generally stably stratified regions are not as well understood. The current consensus is that the mixing in the deep ocean is mainly internal wave-driven, although in many places double-diffusion is also important. In the free atmosphere, mixing may be driven by mean shear and associated shear instabilities as well as internal wave breaking.
Mixing caused by the jetstream at the tropopause and mountain waves breaking near the tropopause are potentially important in the exchange of trace gases such as ozone and greenhouse gases such as carbon dioxide between the troposphere and the stratosphere. Clear air turbulence (CAT) is also of importance from the point of view of safety and comfort of air travelers. There is significant temporal and spatial variability in the dissipation rate aloft, precluding the use of arbitrary constant values. A dearth of measurements contributes to a lack of knowledge about the characteristics of regions of intense small-scale mixing, which gives rise to questions regarding the role of this mixing in climate and weather prediction.

Systems and methods for determining turbulence and turbulent mixing in the free atmosphere

Florida State University Research Foundation