Abstract:
A dual-assist hydropneumatic jack. The dual-assist hydropneumatic jack includes a frame having an upper portion, a lower portion, and a central portion. The central portion defines a chamber therein. A plurality of cylinders are coupled to the frame. A plurality of wheel assemblies are provided coupled to respective ends of the frame, and are adapted to support the jack during loading and unloading. A hydraulic assembly provides hydraulic fluid to and receives hydraulic fluid from the plurality of cylinders. A flow divider is provided between the hydraulic assembly and the plurality of cylinders to divide hydraulic fluid between the respective cylinders. The cylinder includes mechanism for raising and lowering in response to hydraulic fluid being introduced therein and evacuated therefrom. The cylinder is assisted in lowering by the introduction of air into the cylinder and by the weight of the load.

Description:
RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application Ser. No. 60/255,798 filed Dec. 15, 2000. 
    
    
     TECHNICAL FIELD 
     The present invention generally relates to a hydropneumatic jack, and more specifically, a method and apparatus for supporting automobiles and other loads which has dual hydropneumatic capabilities via air assist and hydraulic assist methods, and is adjustable for supporting loads of varying widths. 
     BACKGROUND OF THE INVENTION 
     The use of jacks to raise loads, including lift systems, is known in the prior art. More specifically, lift systems heretofore devised and utilized are known to consist basically of familiar, expected and obvious structural configurations, notwithstanding the myriad of designs encompassed by the crowded prior art which have been developed for the fulfilment of countless objectives and requirements. 
     These jacks may comprise scissor-like lifters, which take up excessive space. This is exacerbated given that users of these lifters may need to access parts of the load, such as vehicles and the like, at precise locations that maybe blocked or otherwise vertically and horizontally inhibit access to these locations. 
     The most commonly available jacking system currently used today are mechanical jacking devices that require the user to place the jack under the object to be lifted, such as one side or end of a motor vehicle, and mechanically operate the jack to extend the lifting axis and raise the object. Mechanical jacking devices have a number of commonly known disadvantages, including lack of stability and strength and the requirement of mechanical effort on part of the user. Another disadvantage of mechanical lifting devices is the amount of space required for the user to effectively utilize the mechanical jack. The space requirement limits the usefulness of these devices in situations where there is not much room for the user to operate the mechanical jack. 
     Pneumatic jacks overcome many of the limitations of mechanical jacking devices and are commonly used to lift various objects in many different situations. A number of such jacks are portable to allow use at locations other than at fixed facilities, such as repair workshops or garages. Once placed under the portion of the vehicle the user desires to raise, air or hydraulic fluid is directed toward the jack to extend it and raise the vehicle. In general, pneumatic jacks are suitable for lifting relatively heavy objects without requiring an undue amount of space or effort on part of the jack user. 
     A number of low profile pneumatic jacks are known. The known pneumatic jacks generally utilize a telescopically extendable lifting axis that extends in response to the introduction of air or hydraulic fluid into the jack. These type of jacks have a number of disadvantages, including known problems with the telescopic member sticking or even jamming during lifting or lowering operations. 
     While the raising and lowering of the jack maybe controlled by air or hydraulic fluid, there remains efficiency concerns with respect to the speed of raising and lowering the device. Such prior devices are limited in this regard by either the flow of hydraulic fluid or the air flow. There also remains supply problems to the raising members, such that multiple pumps are required depending on the number of raising members in the jack. 
     SUMMARY OF THE INVENTION 
     To overcome the problems of inadequate access spacing, cumbersome equipment, and multiple pumps per raising member, the principles of the present invention provide for an apparatus and method for an adjustable hydropneumatic jack that has a dual system for raising and lowering a load, such as a motor vehicle in the like. 
     The dual-assist hydropneumatic jack of the present invention includes a frame having an upper portion, a lower portion, and a central portion. The central portion defines a chamber therein. A plurality of cylinders are coupled to the frame. A plurality of wheel assemblies are provided coupled to respective ends of the frame, and are adapted to support the jack during loading and unloading. A hydraulic assembly provides hydraulic fluid to and receives hydraulic fluid from the plurality of cylinders. A flow divider is provided between the hydraulic assembly and the plurality of cylinders to divide hydraulic fluid between the respective cylinders. The cylinder includes a means for raising and lowering in response to hydraulic fluid being introduced therein and evacuated therefrom. The cylinder is assisted in lowering by the introduction of air into the cylinder and by the weight of the load. 
     In operation, first a dual-assist hydropneumatic jack is provided having a plurality of cylinders having a fluid portion and an air portion. The jack is next located under a load. Lift pads or adapters with lift pads may be placed on the plurality of cylinders. The jack is then raised by providing hydraulic fluid from a hydraulic assembly through a flow divider to a respective fluid portion in a respective one of said plurality of cylinders. To lower the jack, the hydraulic fluid is removed from the fluid portion and air is provided to a respective air portion in said respective one of said plurality of cylinders. 
     In this fashion, valuable access space is saved due to the compact size of the jack. Further, unnecessary pumps are eliminated through the use of a flow divider. Finally, the use of air and the weight of the load provides an efficient and faster means of lowering the jack. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A more complete understanding of the method and apparatus of the present invention may be obtained by reference to the following Detailed Description when taken in conjunction with the accompanying Drawings wherein: 
     FIG. 1 is an exemplary side view of the dual assist hydropneumatic jack according to the principles of the present invention; 
     FIG. 2 is an exemplary top perspective view of the dual assist hydropneumatic jack of FIG. 1, with the supporting posts in two exemplary positions; 
     FIG. 3 is an exemplary isometric perspective of the dual assist hydropneumatic jack of FIG. 1; 
     FIG. 4 is an exemplary perspective view of a wheel assembly for the dual assist hydropneumatic jack of FIG. 1; 
     FIG. 5 is an exemplary exploded perspective view of the hydraulics assembly for the dual assist hydropneumatic jack of FIG. 1; 
     FIG. 6 is an exemplary side perspective view of a cylinder for the dual assist hydropneumatic jack of FIG. 1; 
     FIGS. 7A-7C are exemplary perspective side views of the lift pads and spacers for the dual assist hydropneumatic jack of FIG. 1; and 
     FIG. 8 is an exemplary schematic flow chart of a method according to the principles of the present invention. 
    
    
     DETAILED DESCRIPTION 
     Current jacks, including certain pneumatic jacks, are very costly, space-consuming and slow during operation. There has not been available any apparatus which minimizes space consumption, reduces costs through the elimination of here to fore integral parts, and speeds up operation of the jack. 
     The present invention provides a solution to these dilemmas. Several adjustably movable cylinders are provided herein which are fluidly coupled to a hydraulic assembly. The hydraulic assembly assists in the provision of both air and hydraulic fluid to the adjustably movable cylinders and control the raising and lowering of the cylinders thereby. In addition, the present invention, through its structure, may provide a smaller profile, and therefore accord a user more space when using the present invention. Through the elimination of at least one pump from the assembly of the present invention, the overall cost of the assembly is significantly reduced. In addition, the dual-feed of both air and hydraulic fluid into independent portions of the cylinders allows the cylinders to be raised and lowered more quickly and efficiently. 
     Referring now to the drawings, and more particular to FIGS. 1-3 incombination, there is shown an exemplary side view of a dual assist hydropneumatic jack  10 . The jack  10  includes a substantially rectangular frame  20  having an upper portion  30 , a central portion  40 , and a lower portion  50 . The frame  20  maybe composed of metallic materials and the like. The perimeter walls of the frame  20  forms a chamber  60 . A plurality of slide bars  70  are provided on the upper portion  30  of the frame  20 , and span the width of the frame  20 . In preferred embodiments, the plurality of slide bars  70  are parallel. Best seen in FIG. 3, a plurality of end caps  80  are provided on the respective ends of the frame  20 . 
     Still referring to FIGS. 1-3 in combination, a plurality of stops  90  separate walls of the frame  20  and add structural stability thereto. Best seen in FIGS. 2 and 3, a frame support  100  is centrally coupled in the chamber  60 . At least one cylinder  110  is coupled to the plurality of slide bars  70  via guide assembly  120 . The guide assembly  120  is adapted to slidably move from one end of the frame  20  on the plurality of slide bars  70 . Accordingly, it is preferred that the guide assembly  120  be composed of a suitable material, such as a thermoplastic, to minimize frictional resistance to sliding against the slide bars  70 . The guide assembly  120  is composed of an upper plate  130  and side plates  140 . The upper plate  130  is adapted to receive the cylinder  110  therethrough. The side plates  140  have grooves  150  formed thereon to slidably engage the slide bars  70 . 
     Referring now to FIGS. 1-4 in combination, slidably coupled to the frame  20  via slide channels  160  is an axle assembly  170 . The axle assembly  170  is adjustable through the slide channels  160 , and may be moved towards or away from the jack  10 , depending on the requirements of the system. This is indicated in FIG. 1 by the dashed lines showing the axle assembly  170  in a first and second configuration. The axle assembly  170  includes a wheel assembly  180 . As best seen in FIG. 4, the wheel assembly  180  houses a plurality of wheels  185  which allow the jack  10  to be moved and positioned. The wheel assembly  180  further includes a plurality of biased resilient members  190 , such as a spring, coupled to a base support  192 , such that when the jack  10  is unloaded, the wheels allow the jack  10  to be moved. When the jack  10  is under a predetermined load, the biased resilient members  190  compress and allow the base support  192  to contact the ground. 
     In certain embodiments, an adapter holder  188  is coupled to the lower portion  50  of the frame  20 . The adapter holder has adapter portions  200  for conveniently locating adapters and the like. The central portion  40  of the frame  20  may also have a hydraulic/air connection orifice  210  adapted to receive air and hydraulic lines therethrough as best seen in FIG.  3 . 
     Referring now to FIG. 5, there is shown an exemplary exploded perspective view of a hydraulics assembly  220 . The hydraulics assembly  220  includes a base portion  230  having a pump (not shown) and hydraulic reservoir adapted to receive hydraulic fluid therein (not shown). An air inlet  240  is coupled to the base portion and contains an actuating means  250  thereon. An air source (not shown) is connected to the air inlet  240 . The air source may be what as termed as “shop air”, which typically denotes a readily available air supply in mechanic shops and the like. It is appreciated that the air source may comprise any other air supply having sufficient pressure. 
     In certain embodiments, the actuating means  250  may comprise a switch or valve. A hydraulic delivery mechanism  260  is coupled to the base portion  230  and is adapted to actuate the pump to move hydraulic fluid. A hydraulic removal mechanism  270  is also provided on the base  230  and adapted to allow return flow of hydraulic fluid into the reservoir of the base  230 . 
     Still referring to FIG. 5, coupled to the base  230  and in fluid connection with the hydraulic fluid reservoir is a hydraulic supply line  280 . Likewise coupled is a hydraulic return line  290 . Both the hydraulic supply line  280  and the hydraulic return line  290  are coupled at opposing ends to a flow control  300 . A master hydraulic line  310  is coupled to the flow control  300 , which communicates with the hydraulic supply line  280  and the hydraulic return line  290 . The flow control  300  may have a valve or the like to directs hydraulic fluid either from the supply line  280  to the master hydraulic line  310 , or from the master hydraulic line  310  to the return line  290 . 
     A flow divider  320  is provided coupled to the frame  20  (FIG.  3 ). The flow divider  320  is connected to at least two flow supply lines  330  and to the master hydraulic line  310 . The flow divider  320  functions to divide hydraulic flow from the master hydraulic line  310  to the flow supply lines  330 , and from the flow supply lines  330  to the master hydraulic line  310 . The flow supply lines  330  are fluidly coupled to respective cylinders  110  at hydraulic fluid ports  340 . 
     The air inlet  240  is connected to an airflow divider  350 , which divides airflow between respective airlines  360 . The airlines are fluidly coupled to a respective cylinder at an airport  370 . Air may travel from the air inlet through the airflow divider to the cylinder, and may return from the cylinder to the air inlet, where it is dissipated through the actuating means  250 . Various fittings and the like may be used to couple respective devices and are not limited to what is shown in FIG. 5, depending on the requirements of the system. 
     Referring now to FIG. 6, a side view of an exemplary cylinder  110  is shown. The cylinder  110  has an annular chamber  650  for housing a piston  660  coupled to a shaft  670 . Hydraulic fluid may be fed into the hydraulic fluid portion  680  of the cylinder  110  via the hydraulic fluid port  340  for forcing the piston  650  and shaft  670  upwards in the direction indicated by reference A due to the pressure exerted on the piston  660  by the hydraulic fluid. The piston  660  and shaft  670  are lowered in the direction indicated by reference B when air is introduced into the air portion  690  of the cylinder  110  and removal of the hydraulic fluid. The weight of the load also assists in the lowering of the piston  660  and shaft  670 . A seal  700  is provided along the perimeter of the piston  660  and positioned between the piston  660  and the cylinder  110 . The seal  700  prevents fluid communication between the hydraulic fluid portion  680  and the air portion  690  of the cylinder  110 . 
     Referring now to FIG. 7A, there is shown a lift pad  380 , which is adapted to secure to an adapter  412   a  (FIG. 7B) to fit on one of the plurality of cylinders  110 . Although it is appreciated that the fitting of the lift pad  380  on the respective cylinder  110  can be accomplished in a variety of ways, it is preferred that the lift pad  380  does not move when fitted to the cylinder  110 , thereby minimizing frictional forces when the jack  10  is supporting a load. Although not required, an additional buffer pad  400  may be provided on the lift pad  380  to buffer loads that will be supported thereon. The buffer pad  400  maybe composed of a non-metallic material to prevent frictional wear between the lift pad  380  and the buffer pad  400 . The lift pad  380  may secure to the buffer pad  400  via fasteners and the like. Thus, corresponding orifices  410  are provided in this embodiment adapted to receive a fastener and fixedly secure the lift pad  380  to the buffer pad  400 . 
     Referring now to FIG. 7B, various embodiments of adapters  412   a ,  412   b ,  412   c , are shown in exemplary perspective view. Adapter  412   a  is shown in a first configuration, and has an upper portion  415  having a surface  420 , and a lower portion  425 . Lower portion  425  has a smaller diameter than upper portion  415 . Lower portion  425  is adapted to couple with a cylinder  110  (FIG.  3 ). The surface  420  of the adapter  412   a  is adapted to secure to the lift pad  380  (FIG.  7 A). 
     Adapter  412   b  like wise has an upper portion  430  having an annular orifice  435 , and a lower portion  440 . The lower portion  440  has a smaller diameter than the upper portion  430 . The lower portion  440  is adapted to couple with a cylinder  110  (FIG.  3 ). The annular orifice  435  may be designed to correspond to lower portion  425  of adapter  412   a . Adapter  412   b  may be used to extend the distance between a cylinder  110  (FIG. 3) and the lift pad  380  (FIG.  7 A), such that loads of varying heights may be more easily supported without requiring additional actuation of the jack  10 . 
     Adapter  412   c  has a similar configuration to adapter  412   b , except the length of the adapter  412   c  is different from that of adapter  412   b . Specifically, adapter  412   c  has an upper portion  445  having an annular orifice  450 , and a lower portion  455 . The lower portion  455  has a different diameter than that of the upper portion  445 . The lower portion  455  may be adapted fit on the cylinder  110  and, to adjust the distance between the load that the lift pad, on adapter  412   b . Likewise, adapter  412   b  may secure onto adapter  412   c . Through the interchangeability of the adapters  412   b ,  412   c , various lengths are afforded to the jack  10  to accommodate loads of various heights. 
     Referring now to FIG. 7C, an alternate embodiment of a lift pad  460  is shown. The lift pad  460  includes a lift base  470  having a top surface  475 , and at least one guide  480  coupled thereto. The lift pad  460  may couple to adapter  412   a  (FIG.  7 B), which accordingly couples to a cylinder  110 . The guide  480  assists in the alignment of a load received thereon, and has raised portions  490  at respective ends of the guide  480 . The raised portions  490  serve to prevent movement of a load off of the guide  480 . The length of the guide  480  may be adjusted, as well as the raised portions  490 , depending on the type of load supported thereon. 
     In operation, the jack  10  is first positioned via the wheel assembly  180  under a load, such as a motor vehicle. If adapters are required, appropriate adapters and lift pads may be attached to the cylinders  110  prior to positioning the jack  10 . The width of the jack  10  under the load may also be adjusted via movement of the axle assembly  170  through the slide channels  160  of the frame  20 . 
     The cylinders  110  are then adjusted to the appropriate width of the load. The hydraulics assembly  220  is then actuated via the hydraulic delivery mechanism  260 , and the piston/shaft arrangement in the cylinder raises the lift pad until it contacts the load. Upon contact with the load, the lift pads maybe adjusted to ensure centering of the load on the jack  10 . The hydraulic delivery mechanism  260  may again be actuated to force hydraulic fluid into the flow divider and into a respective cylinder, accordingly raising the load a predetermined amount. The lifting of the load serves to lock the wheel assembly and fix the jack  10  in place. To lower the load, the actuating means  250  is engaged to supply air into a top portion of the cylinder  110 . The hydraulic removal mechanism  270  is also actuated to allow removal of the hydraulic fluid from the cylinder  110  through the flow divider and back to the reservoir. The weight of the load, coupled with the introduction of air in to the cylinder, lowers the load until disengagement from the jack  10 . Wheels of the wheel assembly engage the ground after removal of the load and allow the jack  10  to be removed or repositioned. 
     Referring now to FIG. 8, an exemplary schematic flow chart for a method according to the principles of the present invention is shown. First, the jack is positioned under a load, shown by box  600 . Second, the jack is raised by introduction of hydraulic fluid through the flow divider and into a respective cylinder, exemplified by box  610 . Next, the jack is lowered by removal of the hydraulic fluid from the cylinder through the flow divider, introduction of air into the cylinder, and weight of the load, shown in box  620 . 
     It is to be understood that in certain embodiments, two cylinders are preferred to lift a load for balance and stability, although only one cylinder or more than two cylinders maybe used. It is further to be understood that the present invention offers several advantages over prior jack systems, including but not limited to: a decrease in the amount of equipment such as additional pumps and the associated fluid lines for raising and lowering the cylinders; a reduction in the amount of space required by the jack; and an efficient and quick means for lowering the jack using air and the weight of a load applied to the jack. 
     The previous description is of a preferred embodiment for implementing the invention, and the scope of the invention should not necessarily be limited by this description. The scope of the present invention is instead defined by the following claims.