Patent Application
20100193054
The present application relates to portable air compressors.
Air compressors are well known. Many tools are configured to run on compressed air, which eliminates many of the risks associated with running on electric motors incorporated into the tool itself. For example, where water may be present, electrical short circuits are an ever present danger to the safety of the user of such a tool. Thus, an air compressor in one form or another may be found in most workshops and garages today as an indispensable component of an artisan's equipment. Air compressors have developed from large unwieldy devices that are typically installed on wheels for mobility, on the one hand, to smaller portable systems, on the other hand, that an artisan may carry about by a handle, deposit in a vehicle, carry up floors of a structure, and generally use as an extension of a portable tool that runs on compressed air.
As an extension to the portability of air compressors, some manufacturers have included, as a component of a portable compressor, a tank for storing compressed air that is separable and removable from the main body of the compressor, where the main body includes the electric motor and compressor for compressing the air for storage. This aspect allows the artisan to use the removable tank alone for supplying a limited amount of compressed air if it should be needed at a location remote from where the compressor is located. For example, if an artisan knows that he may have to let some air out of the tires of his vehicle to negotiate a sand track, then he may fill a removable tank with compressed air and take only the tank along with him so that he can inflate his tires once the sand track has been negotiated and his vehicle is back on firmer terrain. This aspect has utility because the artisan need not carry with him the entire compressor with all its heavier components, but may simply select the tank to take with him, and this selection is feasible so long as he does not require the use of a large amount of compressed air at the remote location.
A problem encountered in the art is that separable or removable storage tanks for air compressors are typically cylindrical in profile. As such, they are frequently unstable when placed on the ground because they may tend to roll. Furthermore, systems for connecting a removable storage tank to the compressor tend to add excessive weight to the compressor, which is disadvantageous for portable compressors.
Thus, there is a need in the art for a portable air compressor having a removable tank that will be easy to attach to the compressor, will be easy to remove, will add little weight to the compressor, and which will enable the tank to remain stable when placed on the ground. The present invention addresses these and other needs.
According to a preferred embodiment of the invention, there is described a portable air compressor having features of the present invention. In a preferred embodiment, the compressor comprises a base platform, a motor attached to the base platform, a compressor attached to the base platform and a first cylindrical air tank attached to the base platform, the first tank having an outer diameter with a first radial curvature. A vertically extending rod is attached to the base platform. A second cylindrical air tank is provided, configured to be positioned above, adjacent to, and parallel with the first air tank. A flexible hose connects the first tank to the second tank, wherein the hose is disconnectable from the second tank.
At least two feet are connected to the second tank, each foot including an arcuate portion having a second radial curvature substantially the same as the first curvature, each foot being configured such that, when the second tank is positioned above, adjacent to, and parallel with the first tank, each foot rests on the first tank and the arcuate portion is in contact with the first tank over the length of the arcuate portion. In this manner, an advantageous feature is provided in that the load from the feet is evenly distributed as the second tank is supported on the first tank, and the feet are protected from puncturing the first tank.
A cylindrical collar is attached to an external surface of the second tank, the collar being positioned to slide over an upper portion of the rod when the second tank rests on the first tank. A threaded set screw is inserted through a threaded hole in the collar, whereby tightening the set screw frictionally engages the screw with the rod and locks the second air tank immovable in relation to the compressor, and loosening the set screw disengages the screw from the rod and unlocks the second air tank to render it removable from the compressor. This lightweight locking feature provides flexibility and facility in attaching and removing the second tank from the compressor when desired.
In another aspect of the invention, the compressor includes a handle for lifting the compressor, the handle being positioned substantially above the center of gravity of the compressor. Preferably, the handle is connected to the compressor through a post that is directly connected to the base platform, and an elongate axis of the handle extends horizontally when the compressor is resting on a horizontal surface. These features advantageously allow the compressor to be lifted by the handle without the compressor tilting sideways under the action of gravity.
In yet a further aspect of the invention, the length of the arcuate portion of each foot is preferably between four and seven inches and the feet are spaced apart between nine and twenty inches. Further preferably, each arcuate portion terminates in a lowest point at either end of the arcuate portion, and each point lies in a single plane, thereby permitting the first tank to be placed on a planar surface without a wobble being set up.
The above and other features of the present invention will be explained in greater detail by reference to the attached figures and the detailed description of the preferred embodiment which follows. As set forth herein, the present invention resides in the novel features of form, construction, mode of operation and combination of processes presently described and understood by the claims.
With reference to the Figures there is shown, by way of exemplification and not limitation, an air compressor having features of the present invention, generally identified by the numeral 20. Preferably, components of the air compressor are positioned on a base 22 that includes a plurality of feet 23 for stabilizing the compressor when it is placed on the ground or other support surface. The feet may be adjustable in length by threadable attachment, so that the compressor does not wobble when resting on a planar surface.
Components of the air compressor include an electric motor (not visible) enclosed within a housing 24. The motor drives an air compressor pump (not visible) that may also be enclosed within the housing 24. The air compressor draws in air at atmospheric pressure, and by pump action compresses the air to around 120 p.s.i. before passing the air through a one way pressure valve 70 (
Between the first tank 28 and the first cut-off valve 40, a pressure gauge 44 (
Thus, the first tank 28 and second tank 30 may be filled with compressed air simultaneously. With both cut-off valves 40, 42 open, the compressor is driven by the electric motor, and compressed air is pumped into both tanks under equal pressure. Of course, the pumped air enters the first tank 28 first, via pressure valve 70 (
In use of the air compressor, the artisan may utilize the compressed air in the tanks to run an air driven tool such as a sprayer, drill, or hammer, or other tool (all not shown). However, in utilizing the compressor, the artisan may find it necessary to move the compressor about, to suit the length of the coiled hose and the position of the work being done in relation to the compressor. To facilitate such movement, a handle 26 is provided. Preferably, the handle is oriented with its longitudinal axis horizontal when the compressor is placed on a horizontal surface, and is covered with a polymerized or rubberized grip. The horizontal handle 26 is connected to the base 22 of the compressor via a vertically extending post 46. The horizontal handle 26 is positioned over the center of gravity of the compressor 20, so that the compressor may be lifted by the handle without it tilting sideways under the action of gravity.
Under certain circumstances, the artisan may require to use a limited amount of compressed air in a location that is difficult to reach, or where it is inconvenient to locate the compressor. For example, the artisan may have to perform an application requiring a limited amount of compressed air at the top of a ladder where it would be difficult to elevate the whole compressor. Alternatively, he may require to have a limited amount of compressed air to inflate the tires of a vehicle after driving it on uneven terrain, where it would be inconvenient to transport the entire compressor. In these circumstances, the compressor allows that the second tank 30, filled with compressed air, may be detached and removed from the compressor, and the compressed air within the second tank 30 may be used before the tank is returned and connected with the compressor. When such detachment and removal of the second tank 30 is effected, the second cut off valve 42 is closed, thereby isolating the compressed air in the second tank 30 from the compressed air in the first tank 28. To facilitate easy removal of the second tank, the cut off valve 42 may be combined with a male quick-lock type connector 82 (
To facilitate these features of the compressor 20, the compressor is equipped with novel and useful features that enable the temporary detachment, removal, and use of the second tank 30 from the compressor 20 before the second tank is reinstalled on the compressor after use. To the under surface of the second tank 30, at least two supporting feet 50 are attached. The feet are specially shaped to accomplish a number of objectives. First, the feet are shaped to rest with stability on the first tank 28, and thereby to provide a secure platform for the second tank 30 to rest on the compressor, and in particular, to rest on the first tank 28. Specifically, the feet are shaped to prevent lateral movement of the second air tank 30 perpendicular to the longitudinal axis of the first air tank 28. The feet are also shaped to evenly distribute the load of the second tank 30 onto the first tank 28, so that the feet will not tend to puncture the first tank 28. To achieve these objectives, each foot includes an arcuate portion 52 having substantially the same radius of curvature as the outer diameter of the first cylindrical air tank 28. As best seen in
Moreover, the compressor 20 is provided with a lightweight locking structure for securing the second tank 30 to the compressor when the second tank is placed on the first tank 28 as exemplified in
Thus, there has been described a novel and useful feature for air compressors having a cylindrical air tank, facilitating the temporary removal of an air tank from the compressor, and providing a support combined with locking structure for securing the removable air tank to the compressor during movement.
It will be apparent from the foregoing that, while particular forms of the invention have been illustrated and described, various modifications can be made without parting from the scope of the invention which is set forth in the claims.
