Abstract:
A multi-piston motor/pump is disclosed particularly useful for air motor applications incorporating a cylinder block having a plurality of radially extending pistons and cylinders. Each cylinder is provided with a bronze insert at the top of the cylinder having an intake and exhaust port therein. Rotary valves are mounted on an output shaft and include axial flanges having openings therein that align with the input or exhaust openings in each cylinder. As the rotary valves rotate, the openings therein sequentially align with the input/exhaust ports provided in the bronze inserts such that air or fluid entering each cylinder enters axially of the cylinder. A center mounting plate is secured to the cylinder block and separates the input ports from the exhaust ports to enable fluid flow into the input ports and exhaust from the exhaust ports while isolating each port from the adjacent port in each cylinder.

Description:
RELATED APPLICATIONS 
     This application is related to and claims priority to a provisional application entitled “AIR MOTOR/PUMP” filed Nov. 27, 2013, and assigned Ser. No. 61/909,678. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to multi-piston motors and particularly to air pumps and air motors. 
     BACKGROUND OF THE INVENTION 
     Many industries utilize pressurized air as a source of primary energy to drive equipment in factories and mines and the like. The efficient utilization of this pressurized air to convert the stored energy of the pressurized air to the kinetic energy of a rotating drive shaft permits the implementation of energy utilization complying with the requirements of many work locations. Mines, for example, frequently operate on pressurized air to drive equipment. The present invention provides an efficient utilization of the pressurized air to convert the potential energy of the pressurized air into the kinetic energy of a rotating shaft for driving equipment. Air pumps have innumerable utilization in most industries for the generation of compressed air for its many uses throughout industry. 
     The present invention is directed to the efficient conversion of energy in the form of compressed air to rotary kinetic energy through a rotating shaft and is directed to the inverse wherein energy is supplied to the rotating shaft (such as by an electric motor) to compress air for utilization elsewhere. The present air motor/pump provides a unique system for conveying air through the motor/pump with a minimum of loss thus resulting in increased efficiency. The motor/pump of the present invention may also be used with fluids other than air. 
     SUMMARY OF THE INVENTION 
     The efficiency of a multi-piston motor/pump is greatly increased through the utilization of a rotary valve system that permits the intake and exhaust of fluids such as air into and out of radially disposed cylinders. The system of the present invention includes a plurality of radially extending cylinders having pistons mounted for reciprocating movement within the respective cylinders and connected to a drive shaft. Each cylinder is provided with a bronze insert covering the open top of each cylinder; each bronze insert includes an input and an output port. A center mounting plate is secured to the engine block having the cylinders positioned therein; the center mounting plate is secured to the outer surface of the motor block and positioned between the respective input ports and exhaust ports of the respective bronze inserts. Rotary valves are mounted for rotation with a drive shaft and include axially extending flanges mounted having close tolerances with respect to the bronze inserts. The axially extending flanges are provided with openings that are aligned with the intake port or exhaust port as the rotary valves rotate. When the slots or openings in the radially extending flanges are aligned with the respective port, fluids such as air may enter the respective cylinder axially thereof. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention may more readily be described by reference to the accompanying drawings in which: 
         FIG. 1  is a perspective view of a cylinder block or motor housing utilized in the system of the present invention. 
         FIG. 2  is a sectional view of the motor housing of  FIG. 1  including pistons and including a center mounting plate surrounding the housing of  FIG. 1 . 
         FIG. 3   a  is a plan view of a bronze insert utilized in the system of the present invention. 
         FIG. 3   b  is a side view of the bronze insert of  FIG. 3   a.    
         FIG. 3   c  is an end view of the bronze insert of  FIG. 3   a.    
         FIG. 4   a  is a side elevational view of the center mounting plate utilized in the system of the present invention. 
         FIG. 4   b  is a sectional side view of the center mounting plate of  FIG. 4   a  taken along line A-A. 
         FIG. 4   c  is a sectional view of the center mounting plate of  FIG. 4   a  taken along line B-B. 
         FIG. 5  is an exploded view of a pump/motor incorporating the teachings of the present invention showing the utilization of the cylinder block of  FIG. 1 , the bronze inserts of  FIG. 3   a - 3   c  and the center mounting plate of  FIGS. 4   a - 4   c.    
         FIG. 6   a  is an elevational view of the exhaust rotary valve utilized in the system of the present invention. 
         FIG. 6   b  is a cross-sectional view of  FIG. 6   a  taken along line A-A. 
         FIG. 6   c  is a side-elevational view, partly in section of  FIG. 6   b  taken along line B-B. 
         FIG. 7   a  is a front elevational view of an intake rotary valve incorporating the teachings of the present invention. 
         FIG. 7   b  is a cross-sectional view of  FIG. 7   a  taken along line A-A. 
         FIG. 7   c  is a sectional view of  FIG. 7   b  taken along line B-B. 
         FIG. 8  is cross-sectional view of a pump/motor incorporating the teachings of the present invention showing the components therein in an exhaust cycle. 
         FIG. 9  is a cross-sectional view of a pump/motor incorporating the teachings of the present invention shown in an intake cycle. 
         FIG. 10  is a perspective view of an assembled motor/pump constructed in accordance with the teachings of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIG. 1 , a cylinder block or motor housing  10  is shown housing radially disposed cylinders  12 ,  14 ,  16 ; in the embodiment chosen for illustration, five cylinders are utilized. It will be understood that any number may be used to implement the present invention. In the embodiment chosen for illustration five radially disposed cylinders are evenly spaced at a radial angle of 72° with respect to each other. The cylinders include interiors that may include sleeves  13 ,  15  and  17 , respectively, as shown; the cylinder block or motor housing may be constructed of any suitable material but is preferably made of a steel alloy; in the embodiment chosen for illustration in  FIG. 1 , the housing is generally circular in shape with the outer diameter provided with flats  20  for accepting inserts (to be described). The housing may also be provided with suitable tapped holes  25  to receive corresponding bolts to provide an assembled structure suitable for operation as an air pump/motor. A sectional view of an embodiment of an air pump/motor incorporating the teachings of the present invention is shown in  FIG. 2 . Referring to  FIG. 2 , it may be seen that the cylinder block  10  is secured to a center mounting plate  30  by a plurality of screw bolts  32 . The center mounting plate  30  is secured to a motor stand  35  by bolts extending through flanges in the motor housing to clamp the center mounting plate  30  between the flanges (to be described). The pistons  41  through  45  are mounted for reciprocating movement in the cylinders and are shown in their respective cylinders at various positions in their corresponding piston strokes. Each of the pistons is secured to a corresponding piston rod that is pivotally connected at opposite ends thereof to the associated piston and to a crank shaft. There are various techniques for pivotally attaching piston rods to crank shafts in radial motors/pumps including the use of a master connecting rod such as connecting rod  46 . These techniques are well known in the art and need not be described here. 
     The pistons in  FIG. 2  are shown in corresponding positions within the respective cylinders. Inserts  49  are shown connected to the cylinder block  10  positioned over respective cylinders; the inserts  49  are secured to the flats  20  ( FIG. 1 ) to thereby provide an essentially circular cross-section to the motor housing  10  that closely approximates the interior diameter of the center mounting plate  30 . 
     Referring to  FIGS. 3   a ,  3   b  and  3   c , the inserts  50  described above are shown in greater detail. The inserts  50  are fixed to the cylinder block by appropriate bolts and, when mounted on the cylinder block, cover the outer open ends of the respective cylinders. The inserts  50  are preferably made of bronze and are formed with a flattened center section forming a bridge  52  and a pair of openings  54  and  56  that, when mounted on the cylinder block, communicate with the interior of the corresponding cylinder. These openings  54  and  56  form intake and exhaust ports, respectively, to admit compressed air through the intake port into the cylinder (when used as a motor) and an exhaust port to permit the escape of lower pressure air. The openings  54  and  56  are separated axially of the motor block to form a bridge  52  therebetween. It may be noted that the radius of curvature of the outer surface  58  of the inserts may be slightly different than the outer diameter of the cylinder block to facilitate the provision of sealing clearances between the inserts and rotary valves (to be described). Alternatively, the cylinders could be machined in the cylinder block having enclosed cylinder top ends; in the latter alternative embodiment, intake ports and exhaust ports must be provided in the enclosed cylinder ends and separated axially of the motor to form a bridge and thus permit separation between the intake port and the exhaust port. 
     Referring to  FIGS. 4   a ,  4   b  and  4   c , the center mounting plate  30  is shown in greater detail where it may be seen that the plate is provided with suitable openings  31  for the admission of screw bolts to be secured to the cylinder block  10  ( FIGS. 1 and 2 ) and is also provided with an O-ring groove  57  at its interior edge. This groove receives an appropriate O-ring  58  to form a sealing engagement with the respective inserts  50  and cylinder block  10 . That is, the O-ring  58  of the center mounting plate  30  circumferentially contacts the cylinder block  10  and correspondingly sealingly engages the peripheral surface of the block  10  and is centrally disposed on each of the inserts in contact with the respective bridges to thereby separate the input ports  54  and exhaust ports  56  from each other. 
     Referring to  FIG. 5 , an exploded view of a pump/motor incorporating the teachings of the present invention is shown. The cylinder block  10  is shown having the bronze inserts  50  exposed with one of the bronze inserts removed to reveal the open cylinder beneath the insert. It may be noted that the inserts each provide a pair of openings directly to the corresponding cylinder; one of the openings is an exhaust port and the other opening is an intake port. Intake and exhaust rotary valves  60  and  61 , respectively, are each secured to the drive shaft  63  for rotation therewith while the center mounting plate  30  and cylinder block  10  remain stationary. Each of the rotary valves  60  and  61  is relatively cup-shaped; that is, each has a sloping radially disposed outer surface  60   a  and  61   a , respectively, terminating in an annular axial flange  64  and  65 , respectively. The axial flanges of the respective rotary valves are positioned with appropriate close radial proximity or clearances to the outer surfaces of the respective bronze inserts  50 . Each of the rotary valves is provided with a circumferential slot  68  and  69 , respectively, that provide communication between the cylinder input port or exhaust port and the exterior of the corresponding valve rotor. The circumferential length of the respective slots in the intake and exhaust rotor valves are provided with a predetermined length depending on the application of the system, rotational velocity of the drive shaft, working pressures, etc. Each of the rotary valves  60  and  61  is secured to the drive shaft  63  for rotation therewith while the center mounting plate  30  and cylinder block  10  remain stationary. Circumscribing radial flanges  98  and  99  of the exhaust and input housings  85  and  95 , respectively, contact and clamp the center mounting plate  30  therebetween. When assembled, the housings  85  and  95  each provide an interior volume that communicates for example to a source of pressured fluid through pipe  90  or to an exhaust reservoir such as the atmosphere through pipe  88 . 
     As indicated above, the intake and exhaust rotary valves  60  and  61  are provided with slots  68  and  69 , respectively, that provide air or fluid communication with the cylinders through bronze inserts as described above. The circumferential dimension of the respective slots in the exhaust and intake rotary valves may be determined empirically and will depend on the ultimate use for the motor/pump. The intake and exhaust slots having predetermined circumferential lengths and are timed to provide maximum efficiency under the operating parameters for the particular use including such variables as gas pressure, rotational velocity of the drive shaft, and environmental considerations such as temperature and the like. Efficiency in the present design is maximized by directing air from the air supply and to the exhaust axially of the respective cylinders and directly from the supply of pressurized air (for a motor) into the corresponding cylinders without passage through intervening conduits or passageways. The ability to directly charge and exhaust the respective cylinders is a result of the rotary valve configuration wherein air is admitted to and exhausted from the respective cylinders axially with only the thickness of the corresponding inserts and ports between the supply and exhaust sources and the cylinders. 
     Referring to  FIGS. 6   a ,  6   b  and  6   c , the exhaust rotary valve  61  is shown. It may be seen that the valve is cup-shaped having a flange  65  or lip that extends axially with respect to the motor housing and drive shaft. The internal diameter extending from the interior surface  66  of the flange to the axis of rotation  67  is close to, but slightly greater than, the diameter measured from the bronze inserts secured to the cylinder block to the axis of rotation  67 . In the embodiment chosen for illustration, the flange  66  of the exhaust rotor of  FIG. 6  incorporates a slot  69  extending for approximately 164° circumferentially of the rotor. Thus, when this slot is positioned over a corresponding exhaust port, the exhaust passage is clear to permit the exhaust of air from within the cylinder to the exhaust passageway externally of the motor or pump. 
     Referring to  FIGS. 7   a ,  7   b  and  7   c , an intake rotary valve  60  is shown wherein it may be seen that it is generally cup-shaped and incorporates a circumferential flange  64  that extends axially of the drive shaft of the motor/pump. The flange  64  has an inside diameter extending from the interior surface  69  to the axis of rotation  67  that is slightly greater than the outside diameter measured from the bronze inserts mounted on the cylinder block to the axis of rotation  67 . Thus, with close tolerances and slight clearance, air passage to or from a corresponding cylinder is inhibited unless a machined slot provided in the flange is positioned over the intake port of a cylinder. In the embodiment chosen for illustration, the intake port machined in the flange of the rotary intake valve is shown to be 51.4°. 
     Thus, the intake and exhaust rotary valves provide a timed opening for the passage of air into and out of the cylinders; further, the airflow into and out of the cylinders is directed axially of the respective cylinders and radially with respect to the drive shaft. The preferred embodiment of the rotary valves are shown as cup-shaped wherein the rotary valve is mounted for rotation about the rotational axis of the drive shaft while the flanges of the respective rotary valves extend axially and are positioned in close tolerances to the surface of the intake and exhaust ports of the respective cylinders. Dimensional tolerances between the rotating rotary valves and the stationary ports may more easily be controlled through the utilization of bronze inserts as indicated above; however, it is possible that dual ports may be provided in the cylinder block adjacent the top of each cylinder. The center mounting plate contacts cylinder block and separates the input and exhaust ports permitting pressurized air or fluid to be applied at one side of the center mounting plate while permitting exhaust flow from the cylinder at the opposite side of the center mounting plate. The rotary valves described above are generally cup-shaped; however, the radially extending sloping surface of the rotary valves need not be continuous; that is, radially extending arms rotatable about the drive shaft axis and properly supporting the corresponding axially extending flanges would provide an alternative structure. The term “cup-shaped” is thus intended to include such alternate embodiments. 
     When outer housings are positioned on the pump/motor, the air entering a respective cylinder and exhausting from that respective cylinder travels inward or outward of the cylinder through the corresponding slot in the rotary valve from the space between the corresponding rotary valve and an outer housing (to be described). 
     Referring to  FIG. 8 , a cross-sectional view of an air pump/motor incorporating the teachings of the present invention is shown in an exhaust cycle. The view of  FIG. 8  shows the upper piston  75  at bottom dead center wherein it has just begun its exhaust stroke pushing air out of the cylinder  78  through the exhaust port  80  in the bronze insert, out of the slot  81  provided in the exhaust rotor  84  and into the space  86  between the exhaust rotor  84  and the exhaust housing  85 . In the embodiment chosen for illustration in  FIG. 8 , the exhaust is directed to an exhaust stack or pipe  88  ( FIG. 5 ) connected to or formed as a part of the outer housing  85  such as that shown in  FIG. 5 . It may be noted that the intake stack or pipe  90  ( FIG. 5 ) communicates with the right as shown in  FIG. 8  to fill the space  100  between the input rotary valve  60  and the housing  95 . 
     It may be noted in  FIG. 8  that the center mounting plate  30  is clamped between the radial flanges  98  and  99  of the housing halves and is provided with the circumferentially internal surface O-ring  58  ( FIG. 4   c ) to isolate the respective input and exhaust ports of the corresponding cylinders. Further, the center mounting plate  30  is provided with sealing O-rings  104  and  105  at the clamping surface between the flanges of the housing. It thus may be seen that the input and exhaust passages are isolated with respect to each other. 
     Referring to  FIG. 9 , a cross-sectional view similar to that shown in  FIG. 8  wherein the pump/motor of the present invention is shown during an intake cycle with the piston  75  in the upper cylinder  78  shown at top dead center wherein the intake slot  107  of the intake rotary valve  60  has become aligned with the intake port  108  of the corresponding insert to thus admit air directly into the cylinder. Again, it may be noted that the center mounting plate  30  is in sealing engagement with the cylinder block  10  and bronze inserts to prevent escape of intake air to the exhaust side of the center mounting plate. 
       FIG. 10  is a perspective view of an assembled air motor/pump constructed in accordance with the teachings of the present invention. It may be seen that the exhaust and intake conduits or pipes  88  and  90  extend from the corresponding halves of the external housing. The radial flanges  98  and  99 , respectively, of the external housing halves are shown secured to and clamping the center mounting plate as described above. The drive shaft  110  is shown extending from the assembly. Thus, pressurized air entering in the intake pipe  90  travels between the intake housing half and the intake rotary valve; as the rotary valve aligns ports in its axial flange with input ports of the inserts, the pressurized air is directed into the corresponding cylinder to force the piston radially inwardly to thus provide suitable force for rotation of the drive shaft. As the exhaust rotary valve aligns its exhaust slots with exhaust ports, spent air is directed into the space between the exhaust rotary valve and the exhaust housing. The exhaust air is ultimately directed to the exhaust conduit or pipe  88 . It may be noted that the motor may be reversed by reversing the application of pressurized air; that is, applying pressurized air to the exhaust pipe effectively renders the exhaust pipe as an input to reverse the operation described above and reverse the rotation of the drive shaft  110 . Fluids other than air may be utilized in the motor/pump of the present invention; the efficiencies of the motor/pump are equally applicable when other fluids are incorporated in the operation. 
     The present invention has been described in terms of selected specific embodiments of the apparatus and method incorporating details to facilitate the understanding of the principles of construction and operation of the invention. Such reference herein to a specific embodiment and details thereof is not intended to limit the scope of the claims appended hereto. It will be apparent to those skilled in the art that modifications may be made in the embodiments chosen for illustration without departing from the spirit and scope of the invention.