Implements or apparatus for applying pushing or pulling force – Multiple lifters
Reexamination Certificate
2001-12-17
2004-06-01
Wilson, Lee D. (Department: 3723)
Implements or apparatus for applying pushing or pulling force
Multiple lifters
C254S0930HP, C254S0930VA
Reexamination Certificate
active
06742766
ABSTRACT:
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.
REFERENCES:
patent: 3627268 (1971-12-01), Wills
patent: 4215851 (1980-08-01), Holmen
patent: 4472183 (1984-09-01), Mace
patent: 4746097 (1988-05-01), Chung et al.
patent: 5103937 (1992-04-01), Robertson
Nowell Kevin W.
Waldinger Leo J.
Jenkens & Gilchrist P.C.
Wilson Lee D.
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