Patent Publication Number: US-2012045347-A1

Title: Air Compressor

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of the filing date of and priority to: U.S. Provisional Application Ser. No. 61/375,857 entitled “Air Compressor” and filed Aug. 22, 2010, Confirmation No. 1046; said provisional application being incorporated by reference herein in its entirety for all purposes. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable. 
     BACKGROUND OF THE INVENTION 
     Field of Use 
     The present invention relates generally to an air compressor. More particularly, the present invention relates to an air compressor that is driven by a hand-held portable electric drill. 
     Moynihan, U.S. Pat. No. 4,712,983, (incorporated herein by reference) describes a pneumatic pump that has provision for being driven by a conventional electric hand drill and chuck that are unmodified so that they can be detached by loosening the chuck jaws and used for other purposes. The provision includes first and second input shafts protruding at right angles to each other and connected by a bevel gear on each. In addition to improving drive access, to provide a choice of drive ratios, the bevel gears have different diameters. The rotary output of the shaft and bevel gear arrangement drives a reciprocating piston in a cylinder that, in association with check valves and a hose connection, can inflate a pneumatic tire, at a speed and to a pressure, determined by which drive ratio is chosen. The drill can be freely swiveled about either input shaft to which attached. A gauge indicates cylinder pressure. A frame permits the assembly of drive and pump to be used to pressurize a tank for storage of compressed air. However, a disadvantage of the Moynihan device is that it is a single piston output directly into the discharge hose, generates unbalanced torque, an increased vibration, a lower efficiency, a lower CFM output, and a lower potential psi output. As such, there exists a need for an improved compressor that can be driven from a portable hand drill (electric or battery operated) while also providing for more balanced torque, a decrease in vibration, higher efficiency, greater CFM displacement, a more even flowing air supply, and greater potential psi generation. 
     SUMMARY OF INVENTION 
     In one embodiment of the present disclosure there is described a portable air compressor accessory connectable to the chuck-end of a hand held electric drill, the drill capable of being operated to rotate its chuck-end about an axis of rotation, the compressor accessory comprising: (a) an outer housing; (b) a bearing penetrating the outer housing; (c) a shaft passing through the bearing, the shaft comprising a first end external to the outer housing connectable to the chuck-end of the drill, and a second end connected to a cam device, the shaft capable of rotating along the axis of rotation, the cam device comprising a disc member having a first side connected to the shaft second end and a second side opposite the first side, and a spindle member connected to the disc member second side offset from the axis of rotation; (d) a manifold having an internal manifold chamber for receiving compressed air; (e) a plurality of cylinders lying substantially in the same plane within the housing evenly and radially spaced apart from each other about the axis of rotation, each cylinder capable of receiving a piston, each cylinder comprising an upper cylinder end and a lower cylinder end, a piston capable of moving up and down within the cylinder, the piston having an upper piston end and a lower piston end, a compression chamber formed by the space between the cylinder upper end and the piston upper end, an air inlet conduit comprising an first inlet end external to the outer housing and a second inlet end in fluid communication with the compression chamber, an air exhaust conduit comprising a first exhaust end in fluid communication with the compression chamber and a second exhaust end in fluid communication with the internal manifold chamber; (f) a hub having a center connected to the spindle member; (g) plurality of rod members corresponding to the number of pistons, each rod member having a rod upper end and rod lower end, the lower end of each piston being swivel connected to the upper end of its respective rod, the lower ends rod members being mounted radially about the hub in equal spaced apart relationship, wherein one such rod serves as a master rod and has its lower end fixedly mounted to the hub, wherein the remain rods serve as articulating rods and have their lower ends swivel mounted to the hub; and (h) a nozzle attached to the manifold to permit the controlled release of compressed air from the internal manifold chamber to a desired location external to the housing. 
     In one embodiment, the plurality of cylinders ranges between 3 and 9 cylinders. In another embodiment, the plurality of cylinders comprises 5 cylinders. 
     In one embodiment, the manifold is located substantially within the housing. 
     In another embodiment, the outside of the housing comprises a hand hold to permit the user to hold the housing in a fixed position. 
    
    
     
       BRIEF SUMMARY OF DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate preferred embodiments of the invention. These drawings, together with the general description of the invention given above and the detailed description of the preferred embodiments given below, serve to explain the principles of the invention. 
         FIG. 1  depicts a cross sectional side view of an exemplary air compressor apparatus according to one embodiment of the present disclosure. 
         FIG. 2  depicts a cross sectional end schematic view taken along lines  2 - 2  of  FIG. 1  showing an exemplary air compressor apparatus according to one embodiment of the present disclosure. 
     
    
    
     It will be appreciated that the foregoing drawings illustrate only certain embodiments of the invention and that numerous other variations may be created within the scope of the described invention. 
     DETAILED DESCRIPTION OF INVENTION 
     The above general description and the following detailed description are merely illustrative of the subject invention and additional modes, advantages and particulars of this invention will be readily suggested to those skilled in the art without departing from the spirit and scope of the invention. 
     With reference to  FIGS. 1 and 2 , an embodiment of an air compressor in accordance with the present invention is illustrated. Air compressor  10  comprises an outer housing  12  and an inner housing  14 . The space between the outer housing  12  and the inner housing  14  constitutes a manifold  16  through which the compressed air  1  which is generated by air compressor  10  will be provided to a device external to air compressor  10 . 
     Air compressor  10  comprises a plurality of air cylinders  18 - 22  which lie substantially in the same plane inside of the inner housing  14  in a radially-spaced fashion about axis  24   b.  (Only air cylinder  18  is shown in  FIG. 1  for clarity, and all air cylinders  18 - 22  are illustrated in  FIG. 2 .). Referring to cylinder  18  as an example, the cylinder comprises, as is known in the art, a compression chamber  18   c  for receiving a piston  18   d  capable of being directed up and down within the cylinder. The cylinder  18  has an air intake port  18   a  (with check valve  18   e ) for permitting air (external to the device) to enter the chamber  18   c  when the piston  18   d  moves downward—the check valve  18   e  serving permit air movement only in the direction from outside the device to within the chamber  18   c.  The cylinder  18  has an air exhaust port  18   b  (with check valve  18   f ) for permitting air (internal to the chamber  18   c ) to be directed into the manifold  16  when the piston  18   d  moves upward (compression stroke)—the check valve  18   f  service to permit air movement only in the direction of from within chamber  18   c  to manifold  16 . As the piston  18   d  moves upward (compression stroke), the air with chamber  18   c  is discharged into manifold  16  through exhaust conduit  18   b.  As the piston  18   d  moves downward (decompression stroke), air is drawn from outside into the chamber  18   c  through inlet conduit  18   a.    
     Each air cylinder  18 - 22  has an intake port  18   a,    19   a,    20   a,    21   a  and  22   a,  respectively. Each such intake port extends through the outer housing  12  so that when the air compressor  10  is operating, air from outside the air compressor  10  is pulled into each air cylinder  18 - 22 . Each air cylinder  18 - 22  also comprises an exhaust port  18   b,    19   b,    20   b,    21   b  and  22   b,  respectively. Each such exhaust port extends from its respective air cylinder into the manifold  16  and air from each of the air cylinders  18 - 22  is exhausted into the manifold  16  during operation of air compressor  10 . Each such inlet port and exhaust port employ check valves (not shown except as illustrated for cylinder  18 ) as described in connection with cylinder  18  ( FIG. 1 ). 
     Preferably, the plurality of cylinders ranges between 3 and 9 cylinders. In one preferred embodiment, the plurality of cylinders comprises 5 cylinders. It will be understood by those having the benefit of this disclosure that the number and size of cylinders can be varied based on the desire CFM/psi output. 
     Air compressor  10  further comprises a shaft  24  which extends from outside the air compressor  10  into the inner housing  14 . Shaft  24  has a diameter  24   a  such that it may fit into the chuck of an electric drill, and the diameter  24   a  of shaft  24  may, for example, be ¼″ or ⅜″ or other suitable diameter. Shaft  24  has an axis of rotation  24   b.  The shaft  24  enters housing through a conventional bearing  24   c,  which can be any bearing known in the art, such as, ball bearing, sleeve bearing, roller bearing and the like. The bearing serves to maintain the shaft  24  in fixed rotational alignment. If desired, one or more bearings may be employed for this purpose. In the inner housing  14 , shaft  24  is connected to cam device  25  which comprises a disc  26  or crankshaft (preferably circular in shape) with a spindle  27  which is offset from the center of the circular disc  26  (offset the axis of rotation  24   b ). The spindle  27  is connected to the hub  28 , and a connecting rod  29 ,  29   a  connects each of the air cylinders  18 - 22  to hub  28 . For example, as is known in the art, one of the rods, e.g., master rod  29  (for piston  18   d ) can serve as the master rod (fixedly mounted to the hub, and swivel connected to the piston via, e.g., wrist pin (not shown)). The other rods  29   a  (articulating rods) are then swivel connected to the hub and the piston by connectors (pins) known in the art (not shown). The articulating rods mount on pins that allow them to rotate as the crankshaft and the pistons move. 
     As will be understood, the cylinders are mounted in a fixed manner within the housing to maintain their respective spacing about radius  24   b —in other words, the pistons are arranged in a circle around the crankshaft. The up and down movement of the pistons is generally transverse or perpendicular to the axis of rotation  24   b.    
     In operation, shaft  24  is inserted into the chuck of an electric drill (not shown), and as shaft  24  is rotated by the drill, each of the air cylinders  18 - 22  in turn pulls in air from outside the air compressor and then exhausts that air into the manifold  16 . The pressure of the air in manifold  16  increases as more and more air is exhausted into manifold  16 . The compressed air in manifold  16  may be supplied to an external device, e.g., an automobile tire, via inflater nozzle  30  or other suitable outlet fitting. A flexible hose, or other suitable extension conduit (not shown) could be employed to facilitate directing the compressed air to the desired location. The manifold  16  can also preferably have a pressure relief valve  32  installed to prevent the manifold from becoming overpressurized beyond a desired maximum psi threshold. 
     This specification is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the manner of carrying out the invention. It is to be understood that the forms of the invention herein shown and described are to be taken as the presently preferred embodiments. As already stated, various changes may be made in the shape, size and arrangement of components or adjustments made in the steps of the method without departing from the scope of this invention. For example, equivalent elements may be substituted for those illustrated and described herein and certain features of the invention may be utilized independently of the use of other features, all as would be apparent to one skilled in the art after having the benefit of this description of the invention. Further modifications and alternative embodiments of this invention will be apparent to those skilled in the art in view of this specification.