US2751889A - Air operated motor - Google Patents

Description

June 26, 1956 w, MOHLER 2,751,839

AIR-OPERATED MOTOR Filed April 5, 1954 2 Sheets-Sheet l INVENTOR. MAL/AM fMw-am ATTOE/VEY June 26, 1956 Filed April 5. 1954 W. F. MOHLER AIR-OPERATED MOTOR 2 Sheets$heet 2 INVENTOR. W/LL/A/v/ F/WQHAEP ATTORNEY AIR-OPERATED MOTOR William F. Mohler, Hermosa Beach, Calif., assignor of one-third to John Vedder, West Covina, Calif., and one-third to Borgert Vedder, Fullerton, Calif.

Application April 5, 1954, Serial No. 420,803

3 Claims. (Cl. 121-157) This invention relates to pumping means and deals more particularly with a reciprocating air-operated booster pump.

An object of the present invention is to provide novel and improved self-reversing automatic means that is operated by a continuous flow of pressure fluid, such as compressed air, said means reciprocating the plunger of a booster pump.

Another object of the invention is to provide air-controlled pump-reciprocating means that embodies novel and smooth-acting valve-controlled air-flow-reversing means.

Since a reciprocating pump has alternate power and recovery strokes or movement, it is another object of the invention to automatically use low power for the recovery stroke and, thereby, save in the cost of operation of such pump.

The invention also has for its objects to provide such means that are positive in operation, convenient in use, easily installed in a working position and easily disconnected therefrom, economical of manufacture, relatively simple, and of general superiority and serviceability.

The invention also comprises novel details of construction and novel combinations and arrangements of parts, which will more fully appear in the course of the following description. However, the drawings merely show and the following description merely describes, one embodiment of the present invention, which is given by way of illustration or example only.

In the drawings, like reference characters designate similar parts in the several views.

Fig. 1 is a longitudinal sectional view, partly in elevation, of an air-operated reciprocating pump according to the present invention, the same being shown at the beginning of the power stroke of said pump.

Fig. 2 is a similar view showing the pump at the beginning of its recovery stroke.

Fig. 3 is an end view as seen from the right of Figs. 1 and 2.

Figs. 4, and 6 are cross-sectional views as taken on the respective lines 4-4, 55 and 6-6 of Fig. 1.

The pump that is illustrated embodies, in combination, a positive displacement pump 10 having an inlet 11 and an outlet 12 and controlled by a plunger 13, and airoperated motor means 14 to reciprocate said plunger to etfect an intake of liquid at one pressure in inlet 11 and an outlet of said liquid at an increase pressure from outlet 12. This invention pertains particularly to the motor means 14.

Said air-operated motor means 14 comprises, generally, a valve body 15, an air cylinder 16 extending from said body and at the end thereof, mounting displacement pump 10, a piston 17 operable in said cylinder 16, a valve pilot and guide element 18 extending from said piston 17 into the body 15, a pilot shifter valve 19, and an air-piston actuating valve 20, said elements 18, 19 and 2% being coaxial and on the axis of cylinder 16.

The valve body preferably comprises a metal casting formed, at one side, with an inlet port 21 for pressure hired States Patent 6 fluid such as compressed air and, at the opposite side, with an exhaust port 22. Said body is provided with transverse walls 23, 24, 25 and 26 longitudinally spaced from each other. A common longitudinal bore 27 is provided in said walls, the same being of a diametral size to slidingly accommodate actuating valve 20. A cored passage 28 communciates the annular space 29 between walls 25 and 26 with inlet port 21. A similar annular space 30 between walls 23 and 24 communicates with exhaust port 22. As best seen in Fig. 4, a baflie wall 31 is placed in front of said port to obviate direct escape of air through said port. An annular chamber 32 is defined between transverse walls 24 and 25 and an intermediate longitudinal passage 33 communicates chamber 32 and the inside of air cylinder 16.

The air cylinder 16 is longitudinally defined between body 15 and an opposed cylinder end 34 and circumferentially defined by a cylinder tube 35. Said body 15 and end 34 are connected to said tube in a similar manner. As shown, a set of bolts 36 extends through said body and said end and the same are threadedly engaged with a ring 37 within the cylinder and held against endwise displacement by a snap ring 38 in an internal groove in said cylinder tube. Since said body 15 and end 34 abut the opposite end of cylinder tube 35, the heads of said bolts effectively lock the assembly of body 15 and cylinder 16.

The piston 17 reciprocates between body 15 and end 34 and has plunger 13 secured thereto substantially as shown. It will be noted that the eifective area of said piston 17 is substantially larger than that of plunger 13 so that the total force imposed on the larger area of said piston will be effective as a pressure on the end of plunger 13. Thus, the unit pressure exerted by plunger 13 is considerably greater than the unit pressure exerted by piston 17.

Piston 17, on the side directed toward the cylinder end 34, is provided with lateral passages 39, the same extending from a central bore 40.

The valve pilot 18 is connected to piston 17 and comprises a tubular member 41 that has a nipple 42 in threaded connection with said piston. Near its outer end said tubular member 41 is provided with a plurality of radial apertures 43a. Said valve pilot 18 is guided in a bearing 43 in the bore of wall 26.

The pilot shifter valve 19 comprises a tubular member 44 that is slidingly fitted within the pilot valve 18 and is substantially longer than the latter. The outer end of valve 19 is closed at 45 and the inner end is fitted with a valve plug 46 provided with a restriction orifice 47. The hollow interior 48 of tubular member 44 is opened to the outside of said member by plural sets of ports 49, 50, 51 and 52. Said valve is provided with an annular outwardly directed shoulder 53 which is limited in outward position by an inner bearing 54 provided in member 41 of the pilot valve.

The air piston actuating valve 20 comprises a tubular member 55 that has a sliding fit in bore 27 and, with clearance, encircles the valve pilot and guide element 18. The outer cylindrical face of member 55 is reduced at 56 to form an annular passage defined by outwardly directed shoulders 57 and 58. Between these shoulders, and depending on the position of valve 26, communication between chambers 29 and 32, and 30 and 32 is pro vided. Member 55, near its outer end, is provided with an internal flange 59 that slidingly seals around shifter valve 19. This flange also serves as one end abutment for a compression spring 60, the other abutment being provided by a shoulder 61 in a cap 62 that closes the outer end of bore 27. Said cap is formed to have a considerable extension 63 and the same is provided with an O-ring 64 that serves to seal around valve member 44 when the latter is projected outwardly.

In the position of Pig. 1, piston 17 is retracted as is plunger 13. Spring 60 is free to urge actuating valve 20 against bearing 43 to bring the reduced portion 56 across transverse wall so that there is direct communication between chambers 2% and 32. Consequently, compressed air admitted through inlet port 21 will impinge on the outer face of piston 17 and project said piston toward the left to cause plunger 13 to displace fluid past valve 65 and outward through outlet 12. As will later be seen, there is low pressure on the left side of piston 17 at this time and the plunger thus moves in its power stroke under the total force applied by the air impinging on piston 17.

As the piston 17 reaches the end of this power stroke, the apertures 43a, in tubular member 41, move from the right side of bearing 43 to the left side, as in Fig. 2. Therefore, the pressure built up in cylinder behind piston 17 enters the interior 4% of pilot valve shifter 19 through said apertures 43a and ports 50, and, from said interior d8, enters the interior of actuating valve 29 and exerts a force on flange 59 of said valve that overcomes spring 6t and shifts said valve to the right, as in Fig. 2.

When said valve 29 shifts to the right, the left end 7 thereof leaves bearing 43 and opens direct communication between inlet passage 28 and chamber 29 and the interior of said valve. Thus, the pressure air entering port 21 is utilized to maintain the valve 20 shifted to its new position. Said pressure air also enters interior 48 of valve 19 through ports 52 to exert an outward force on the closed end of valve 19 and to seep slowly through orifice 47, and through passages 39, to the left side of piston 17. Since the recovery stroke of said piston needs merely enough pressure air to move the mass of said piston, only a small amount of air through orifice 4? is needed.

Since actuating valve 2i), when it shifted to the right, also brought annular spaces 30 and 32 in communication, cylinder 16, behind piston 17, is vented to exhaust port 22. There is little resistance to recovery movement of the piston. Therefore, valve 19 may strike the closed end of cap 62 with some force. To obviate this, when said valve .19 encounters O-ring 64, the same creates a cushion of trapped air which acts as a buffer to said valve 19.

As valve 19 moves toward the right, ports 52 move past the sealed flange 59 in actuating valve 20. This brings pressure air on the spring side of flange'59 and equalizes the pressure on both sides of said flange. Consequently, spring 69 is free to return the actuating valve 20 to the position of Fig. l and the air pressure that has been applied to the left-hand or low pressure side of the piston 17 is allowed to escape through vent a and the exhaust port 22, so that the cycle of operation is ready to repeat.

While the foregoing illustrates and describes what is now contemplated to be the best mode of carrying out the invention, the construction is, of course, subject to modification without departing from the spirit and scope of the invention. it is, therefore, not desired to restrict the invention to the particular form of construction illustrated and described, but to cover all modifications that may fall within the scope of the appended claims.

Having thus described the invention, what is claimed and desired to be secured by Letters Patent is:

1. An air-operated motor comprising an air cylinder, a valve body having an axial bore and provided with transverse walls, to which said bore is common, and which divide the interior of the body into an air inlet passage, an air exhaust passage and an intermediate passage in communication with said air cylinder, 8. piston in said cylinder and having passages therethrough, a sleeve valve in said bore controlling flow of air between the three mentioned passages in said body, a spring normally holding said sleeve valve in position to communicate the inlet and intermediate passages, a tubular member concentric to said sleeve and connected to the piston, said member being in communication with the passages of said piston having apertures near the end thereof remote from the piston, a pilot shifter valve slidably engaged in said tubular member and said sleeve valve, said shifter valve having a hollow interior in communication with said member and said sleeve valve through plural sets of ports, and an orifice plug in one end of said pilot shifter valve to permit said cylinder to vent when said spring holds said sleeve valve in said aforesaid position.

2. A motor according to claim 1: an internal flange on the sleeve valve in sliding and sealing engagement with the shifter valve, said spring engaging said flange to hold the sleeve valve in said aforesaid position.

3. A motor according to claim 1: an internal flange on the sleeve valve in sliding and sealing engagement with the shifter valve, said spring engaging said flange' to hold the sleeve valve in said aforesaid position, and at least one set of the ports in the shifter valve being movable from a position on one side of said flange to a position on the other side of said flange.

4. A motor according to claim 1: said body being provided with a cap closing the end of the mentioned bore, and said shifter valve being elongated so that one end is adapted to engage the cap, a sealing ring within the cap engaging said end to form a movement-arresting air cushion between the cap and the valve end.

5. A motor according to claim 1: a bearing mounted in said body adjacent to said cylinder, said tubular memher being slidable in said bearing, and the apertures in said member being movable from a position on one side of said bearing to a position on the other side'of said bearing.

6. A motor according to claim 1: a bearing mounted in the body wall adjacent said air cylinder, said tubular member being slidable in said bearing, and said sleeve valve held against said bearing by said spring to communicate the inlet and intermediate passages.

7. An air-operated motor comprising an air cylinder,

*a valve body having an axial bore enclosing one end of said cylinder, said body having an air inlet port and an exhaust port and a plurality of transverse walls dividing said body into an air inlet passage and an air outlet passage and an intermediate passage, said walls provided with a longitudinal bore co-axial with the axis of said cylinder, a sleeve valve slidable within said bore and controlling the flow of air through the three mentioned passages, a bearing mounted in the body walladjacent said cylinder, a cap mounted in the body wall farthest away from said cylinder and enclosing said bore, a spring biased between said sleeve valve and said cap to hold said sleeve against said bearing, said sleeve when held by said spring permitting air pressure to pass from said inlet passage to said intermediate passage, a piston within said cylinder movable on application of air pressure through said intermediate passage, a tubular member connected to said piston and slidably engaged with said bearing, said member having apertures in one end that move from a position on one side of said bearing to a.

position on the other side of said bearing when said piston exerts a power stroke, an elongated shifter valve slidably mounted at one end within said member and at the other end within said sleeve, said shifter valve being hollow and having ports to permit air pressure within said cylinder to escape throughsaid apertures and through said hollow portion, said escaping air moving said sleeve valve against said spring to permit the remaining air pressure within said cylinder to vent through said intermediate and outlet passages.

8; A motor according to claim 7: said pistons having passages therein. communicating the. low pressure side 6 thereof with the tubular member, and an orifice plug References Cited in the file of this patent mounted in the end of Said shifter valye said mem- UNITED ST P her to permit air pressure from said cylinder to pass 641,132 Moore Jan- 1900 through said apertures and said ports in said shifter valve through said orifice to pressurize the low pressure side 5 of said piston.

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