Hoists come in different kinds, including front mount, single acting telescopic hoists and underbody frame type hoists using double acting cylinders. Differences exist between these two types of hoists. While front mount telescopic hoists require substantial amounts of hydraulic fluid for operation, which in turn requires large and heavy reservoirs filled with expensive hydraulic fluid, which must be pumped by large and heavy, high volume pumps, by contrast, underbody hoists typically require only a third as much hydraulic fluid, or even less, and much smaller pumps and reservoirs. Underbody hoists using double acting cylinders also offer a number of options that operators may be unaware of, or choose not to use.
For example, hydraulic hoists using double acting cylinders are common in the trucking industry, but are often misused by using hydraulic power only to raise, but not lower, a dump body. This misuse occurs when the operator disengages the hydraulic power unit after raising the dump body and dumping a load, and thereby lowers the dump body by gravity alone to its original position. This action often results in air entering the hydraulic system, the presence of which may decrease the operator's control of the dump body, which could become erratic and possibly dangerous. Similarly, when the cylinder of the hydraulic hoist does not “lock down” the dump body, it is free to rattle and bounce during transit.
In view of the above, it is apparent that there exists a need in the art for a hydraulic system, for truck hoists or other uses, which addresses, overcomes, mitigates, or solves one or more of the above problems and/or drawbacks and/or inefficiencies in the art. It is the purpose of this invention to fulfill this and/or other needs in the art which will become apparent to the skilled artisan once given the following disclosure.
USPTO Backgrounds
USPTO Backgrounds