US3272081A

US3272081A - Air motor

Info

Publication number: US3272081A
Application number: US422907A
Authority: US
Inventors: Vedder Borgert; Vedder John
Original assignee: Individual
Current assignee: Individual
Priority date: 1965-01-04
Filing date: 1965-01-04
Publication date: 1966-09-13
Anticipated expiration: 1983-09-13

Description

Sept. 13, 1966 an VEDDER ETAL 3272M AIR MOTOR Filed Jan. 4, 1965 wzzzzz 0 6E? 5 J /WV V5005? ATTORNEY United States Patent 3,272,081 AIR MOTOR Borgert Vedder, Fulierton, Calif, and John Vedder, Torrance, Calif. (both of 14032 S. Avalon Blvd, Los Angeles, Calif. 90061) Filed Jan. 4, 1965, Ser. No. 422,907 6 Claims. (Cl. 91-228) This invention relates to an air motor for causing a member to reciprocate, for example, the hydraulic piston or ram of a pump.

An object of the invention is to provide a reciprocating air motor that operates on the simple and eflicient principle of power magnification through the use of differential piston areas.

Another object of the invention is to provide an air motor embodying a novel form of valving that reverses air flow with each reciprocative movement in a smooth and eflicient manner.

A further object of the invention is to provide an air motor that operates efliciently at high unit pressures of air and with positiveness of opreation due to eflicient sealing between moving parts to minimize internal leakage. This feature insures that the motor components move fully and positively in the operation.

This 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 above objects are realized in an air motor that comprises a body with an air inlet and an air exhaust, and provided with a set of ports that are variously connected to said inlet and exhaust and to a passage leading to the upper end of an air cylinder and constituting operating air pressure against the upper face of an air piston in said cylinder, said ports opening into an axial bore in said body; a four-way valve sleeve movable in said bore between upper and lower positions with a spring to bias the same to its lower position when the air pressure there on is balanced; a pilot valve guided in said sleeve and provided with a piston at one end, said pilot valve being shiftable by air pressure controlled by the four-way valve sleeve; a check valve carried by the pilot valve that opens to the pressure of air flow in the interior of the pilot valve to provide operating air pressure against the under face of said air piston in the air cylinder; a cylindrical stem on the air piston in which the piston on the pilot valve is guided; and sealing means between the body and the stem to provide sealing therebetween to insure full operative movement by air of the four-way valve between upper and lower positions.

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 and which is based on the accompanying drawing. However, said drawing merely shows, and the following description merely describes, one embodiment of the present invention, which given by way of illustration or example only.

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

FIG. 1 is a quarter-section view of the present air motor with the parts thereof in the position to direct compressed air against the under surface of the air piston, the other quarter-section portion being the same except that the air inlet and exhaust are omitted.

FIG. 2 is a similar view of said air motor with the parts thereof in the position to direct compressed air against the upper surface of said air piston.

The present air motor is provided with a body 5 that has an air inlet port 6 that leads to a manifold 7, an

air exhaust port 3 that leads to a manifold 9, and one or more air passages 11), leading from a manifold 11 and opening into the upper end of an air cylinder 12 extending from the lower end of the body 5. Said body 5 has a small bore 13 in its upper end with a compressible bumper 14 at the upper end of the bore, an O-ring seal 15 being provided adjacent the lower end of said bore. A counterbore 16, provided with a bumper 17, extends from the lower end of the small bore 13.

A larger counterbore extension .18 of the counterbore 16 has the bumper 18 at its upper end, a still larger counterbore 19 extending from the counterbore 18, the three manifolds 7, 9 and 11 opening on the bore 19. A bearing 20 is fitted into a counterbore extension 21 at the lower end of the body 5, a sealing O-ring 22 in the body sealing the fit. A bumper 23 is provided in the upper face of said bearing 20 which has an inner bore 24 in which an O-ring 25 is fitted.

A liner 26 is fitted into the counterbore 19 between the bearing 21) and the shoulder that is formed between the latter counterbore and the bore .18 from which it extends. Said liner is provided with lower longitudinally spaced ports 27 that connect the manifold 7 with the inner bore of said liner, with upper longitudinally spaced ports 28 that connect the manifold 9 with said liner bore, and with intermediate ports 29 that connect the manifold 9 with said liner bore.

A four-way slide valve 30, in the form of a tubular portion 31, has a sliding fit in the bore of the liner 26, with its upper end 32 engaged with the bumper 17 when the valve 30 is in raised position, as in FIG. 1, and with its lower end 33 engaged with the bumper 23 in the upper face of the bearing 21?, when said head is in lowered position, as in FIG. 2. An inner flange wall 34, provided with an O-ring 35 in the bore of said wall extends from the tubular portion 31 of the head 30. Ports 36 are provided in the part of the portion 31 that extends above the flange wall 34. An annular external groove 37 has operative association with the

ports

27 and 28 to communicate the same, according to the raised and lowered positions of the head, with the ports 29. It will be noted that the bore 30 and the bore of the flange wall 34 are the same diameter. A spring 38 between said flange wall 34 and an abutment wall formed by

bores

13 and 16, biases the valve 30 to its lower position.

A pilot valve 39 has a sliding fit in the mentioned bore 30 and the bore of the flange wall 34, the same having an axial bore 41 that is closed at the top and is provided with two sets of

radial ports

41 and 42 that pass air from within the four-way valve 30 to the bore 41). The lower end of pilot valve 39 comprises a piston 43, a skirt 44 below said piston being provided with radial ports 45.

The valve 39, in its bore 40, fixedly mounts a valve seat 46 against which a spring 47 biases a valve body 43 which has angular ports 49 in its Wall as well as a set of longitudinal passages 50. Said latter ports and passages are open to the bore 411 of the valve 39, the former being closed when the body 48 is seated on seat 46, and the latter being closed by a check valve 51 which opens only in a downward direction under pressure of air in the valve passage 40.

An air piston 52 has sliding operative engagement in the cylinder 12 which is of larger size than the largest bore in the body 5, the same being fitted with an O-ring 5 3 to seat against the cylinder. Said piston carries an axially disposed ram 54 of considerably smaller size than the piston, said ram, due to its smaller size, having a power or pressure factor on its operative end that is the same as the total air pressure on either side of the piston.

The air piston 52 is provided with an upwardly directed stem 55 that comprises a tubular extension that has sliding fit in the bore 24 of bearing and an inner surface that constitutes a cylinder for the piston 43. A ported inwardly directed flange 56 at the upper end of said stem 55 overstands the piston 43, an O-ring 57 forming a bumper between said flange and said piston. An O-ring 58 on the upper end of said stem 55 is arranged to seal against the bore 24 of the bearing 20 when the piston 52 is at the end of its down stroke. Ports 59 open on a relieved portion of the outer surface of the stem 55.

The ram 54 is provided at its upper end with an enlargement 60 that is connected to a lower extension of the air piston 52. The upper portion of said enlargement is provided with a bumper pad 61 which is adapted to be abutted by the lower skirt end 44 of the valve 39. Above said enlargement, the air piston is provided with passages 62 that open from the inner cylinder bore 63 in which the piston 43 of said valve 39 operates and into which the radial ports 45 open.

Operation At the end of the down stroke of the ram 54, the four-way valve is in the raised position of FIG. 1. Compressed air at inlet 6 will pass through the lower of the ports 27 of liner 26 and enter the bore of the valve 30. This air, through

ports

41 and 42, enters the bore of the pilot valve 3 9, creating an upward force against the blind end of the bore 40 that raises the valve 39 and divides into a downward air flow that passes through ports in the valve body 48 and opens the check valve 51, said air then entering the bore 63 and passing through passages 62 to create a force in the direction of arrow 64 between the bottom of the cylinder 12 and the under surface of the air piston 52.

As a result of such air flow, the valve 39 will move upwardly while the air piston 52 is moving through its up stroke. During this up stroke of the air piston, the same displaces air in the upper end of the cylinder; this air, by way of passages 10, port 29, groove 37, and the lower ports 28, exhausts through the port 8.

It will be noted that the valve 39 cannot move up faster than the piston 52 due to the interengagement of the piston 43 of said valve and the flange 56. This insures that the valve 39 cannot prematurely reach its fourway valve-reversing position. This interengagement, however, allows the piston 52 to make its full upward recovery movement to the position of FIG. 2 before the valve reaches its maximum raised position against the bumper 14, as shown. In practice, said valve 39 need not raise to such maximum position, but only enough so that the ports 42 thereof pass the O-ring 35 of the distributor head 30 so that the air pressure in the bore 40 can enter the counterbore 16 of the body 5. Since, by the time the ports 42 pass O-ring 35, the upper end of the valve 39 has entered the bore 13 and is sealed by O-ring 15, the pressures in said counterbore 16 and in the inside of the air distributor 30 below the flange 34, are equalized. As a consequence, the spring 38 becomes eflective to move the four-Way valve downward to the position of FIG. 2.

In this position, compressed air at inlet 6 will pass through the upper of the ports 27, groove 37, and passages 10, and enters the upper end of the cylinder 12 to produce a force on the piston 52, according to arrow 65, to move the latter downward in its power stroke. This down stroke of the piston 52 causes displacement of air in the cylinder 12 below said piston, this air passing through ports 62 into bore 63, unseating the valve body 48 and passing through angular ports 49 into the bore 40 of the valve 39. This air passes through ports 41 when the same become uncovered due to the downward movement of the tubular extension and its flange 56 of the piston 52, into the interior bore of the four-way valve 30. At the same time, air from bore 40 will pass through ports 42 into

counterbores

16 and 18 and will exhaust through the upper of ports 28 through the exhaust port 8. Upon such exhaust taking place, the pressure within the four-way valve 30 will become effective to shift the latter upwardly to the position of FIG. 1, terminating the down or power stroke and completing the cycle of operation.

Due to the sliding fit among the

valves

30 and 31, the liner 26, the stem 55 and the piston 52 in the cylinder 12, the fit between the bearing 20 and the stem 55 is quite loose. When the annular clearance at that point is added to the small ports 59 and the ports in the flange 56, the air-passing area between the interior of the fourway valve and the upper port of the air cylinder is large.

Under low air pressure of between five and twenty pounds, the pressure in the interior of valve 30 leaks to the air cylinder 12 too rapidly for the air inlet through the lower of the ports 27, as the same is being uncovered, to complete the full up movement of the valve 30. The latter may hang in an intermediate position resulting in a constant bypass of air around the bearing 20. The O-ring 58 is provided to prevent such bypass of air, since the same closes the annular clearance between said bearing and the piston stem 55, leaving only the small ports 59 and those in the flange 56 to exhaust the interior of the four-way valve. Hence, the four-way valve will shift fully to its maximum opening of the lower of the ports 27.

It is this feature that enables the present air motor to operate with compressed air as low as five psi. and as high as one hundred p.s.i., or more.

While the foregoing has illustrated and described what is now contemplated to be the best mode of carrying out the invention, the construction is, of course, subject to modirfication without departing from the spirit and scope of the invention. Therefore, it is 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 motor comprising:

(a) a body with an air inlet and an air exhaust and having a bore and two sets of ports connecting said bore and the inlet and exhaust, respectively,

(b) an air cylinder extending from said body and open to said bore,

(0) the body having ports intermediate the mentioned two sets of ports and passage means from said intermediate ports to the portion of the cylinder adjacent the body,

((1) an air piston in said cylinder provided with a hollow stem operative in the body bore and having ports opening through the bottom thereof,

(e) a four-way valve sleeve movable in said bore between upper and lower positions with a spring to bias the sleeve to its lower position, said sleeve in one position providing communication between the air inlet and the body bore and between the air exhaust, through the passage means, and the upper portion of the air cylinder, and said sleeve in the other position providing communication between the air inlet and said passage means and upper portion of the air cylinder, and between the air exhaust and the body bore,

(f) a pilot valve having an axial bore and guided in said sleeve provided with a piston at one end, said pilot valve being shiftable by air pressure from the inlet entering the body bore, as controlled by the four-way valve sleeve,

(g) a check valve, carried by the pilot valve, that opens to air pressure in the bore thereof to provide operating pressure, through the ports in the air piston, on the under surface of the latter, and

(h) a second check valve carried by the pilot valve that opens in the opposite direction to pass pressure air from beneath the air piston into the body bore.

2. An air motor according to claim 1 in which the fourway valve sleeve is provided with a flange in guiding and sealing engagement with the pilot valve, ports being provided in said valve opening the axial bore of the latter to the body bore in one position of the valve, said ports providing pressure-balanced air on opposite sides of said flange, the mentioned spring shifting the four-way valve sleeve to said other position during such air-balanced condition of pressure in the valve bore.

3. An air motor according to claim 2 in which the fourway valve sleeve is provided with portions formed to open the ports in the body that are directly connected to the exhaust of the body, when said sleeve is shifted by said spring.

4. An air motor comprising:

(b) an air cylinder extending from said body and open to said bore,

(c) the body having ports intermediate the mentioned two sets of ports and passage means from said intermediate ports to the portion of the cylinder adjacent the body,

(d) an air piston in said cylinder provided with a hollow stem operative in the body bore and having ports opening through the bottom thereof,

(g) a check valve, carried by the pilot valve, that opens to air pressure in the bore thereof to provide operating pressure, through the ports in the air piston, on the under surface of the latter,

(h) a second check valve carried by the pilot valve that opens in the opposite direction to pass pressure air from beneath the air piston into the body bore,

(i) a bearing provided in the body and having a bore concentric with and smaller than the body bore, the air piston stern extending through said bearing bore, and

(j) means carried by the piston stem to seal against said bearing bore when the air piston is projected from the body bore.

5. An air motor comprising:

(b) an air cylinder extending from said body and open to said bore,

(d) an air piston in said cylinder provided with a hollow stern operative in the body bore and having ports opening through the bottom thereof,

(i) the air piston stem having ports therein that open the bore of the body to the air cylinder above the air piston,

(j) a bearing provided in the body at the lower end thereof and having an axial bore concentric with and smaller than the body bore, the air piston stem extending loosely through said bearing bore, and

(k) means carried by the piston stem to seal against said bearing bore when the air piston is projected from the body bore.

6. An air motor according to claim 5 in which the latter means comprises a sealing ring that closes air flow through said loose fit between the bearing bore and stem to lessen the air flow from the body bore to the air cylinder above the air piston and retaining such pressure in the body bore as to insure full shift of the four-way valve sleeve.

References Cited by the Examiner UNITED STATES PATENTS 2,296,647 9/1942 McCormick 91-308 2,361,757 10/1944 Fink 91-313 3,171,809 3/1965 Cox 91222 MARTIN P. SCHWADRON, Primary Examiner.

P. E. MASLOUSKY, Assistant Examiner.

Claims

1. AN AIR MOTOR COMPRISING: (A) A BODY WITH AN AIR INLET AND AN AIR EXHAUST AND HAVING A BORE AND TWO SETS OF PORTS CONNECTING SAID BORE AND THE INLET AND EXHAUST, RESPECTIVELY, (B) AN AIR CYLINDER EXTENDING FROM SAID BODY AND OPEN TO SAID BORE, (C) THE BODY HAVING PORTS INTERMEDIATE THE MENTIONED TWO SETS OF PORTS AND PASSAGE MEANS FROM SAID INTERMEDIATE PORTS TO THE PORTION OF THE CYLINDER ADJACENT THE BODY, (D) AN AIR PISTON IN SAID CYLINDER PROVIDED WITH A HOLLOW STEM OPERATIVE IN THE BODY BORE AND HAVING PORTS OPENING THROUGH THE BOTTOM THEREOF, (E) A FOUR-WAY VALVE SLEEVE MOVABLE IN SAID BORE BETWEEN UPPER AND LOWER POSITIONS WITH A SPRING TO BIAS THE SLEEVE TO ITS LOWER POSITION, SAID SLEEVE IN ONE POSITION PROVIDING COMMUNICATION BETWEEN THE AIR INLET AND THE BODY BORE AND BETWEEN THE AIR EXHAUST, THROUGH THE PASSAGE MEANS, AND THE UPPER PORTION OF THE AIR CYLINDER, AND SAID SLEEVE IN THE OTHER POSITION PROVIDING COMMUNICATION BETWEEN THE AIR INLET AND SAID PASSAGE MEANS AND UPPER PORTION OF THE AIR CYLINDER, AND BETWEEN THE AIR EXHAUST AND THE BODY BORE, (F) A PILOT VALVE HAVING AN AXIAL BORE AND GUIDED IN SAID SLEEVE PROVIDED WITH A PISTON AT ONE END, SAID PILOT VALVE BEING SHIFTABLE BY AIR PRESSURE FROM THE INLET ENTERING THE BODY BORE, AS CONTROLLED BY THE FOUR-WAY VALVE SLEEVE, (G) A CHECK VALVE, CARRIED BY THE PILOT VALVE, THAT OPENS TO AIR PRESSURE IN THE BORE THEREOF TO PROVIDE OPERATING PRESSURE, THROUGH THE PORTS IN THE AIR PISTON, ON THE UNDER SURFACE OF THE LATTER, AND (H) A SECOND CHECK VALVE CARRIED BY THE PILOT VALVE THAT OPENS IN THE OPPOSITE DIRECTION TO PASS PRESSURE AIR FROM BENEATH THE AIR PISTON INTO THE BODY BORE.