US3699846A

US3699846A - Air motor

Info

Publication number: US3699846A
Application number: US102720A
Authority: US
Inventors: Joseph M Stomper
Original assignee: Stewart Warner Corp
Current assignee: Stewart Warner Corp
Priority date: 1970-12-30
Filing date: 1970-12-30
Publication date: 1972-10-24
Anticipated expiration: 1989-10-24
Also published as: GB1380569A

Abstract

The following specification describes an air motor formed of three coaxial cylinders or housings assembled by a simple threading operation with one end housing having a spring biased valve assembly detachably inserted therein for directing air to opposite piston sides. A shuttle in one housing controlling the valve assembly is guided by a sleeve bearing to minimize wear, and a conduit transmitting air from the valve assembly to the opposite end housing is simply connected by a single pair of fittings.

Description

Umted States Patent 1 3,699,846 Stomper Oct. 24, -1972 [54] AIR MOTOR FOREIGN PATENTS OR APPLICATIONS Inventor: Joseph p n Norridge. 45s,221 7/1949 Canada ..91/346 [73] Assignee: Stewart-Warner Corporation,

Chicago 11 Primary Examiner-Martin P. Schwadron Assistant Examiner-Irwin C. Cohen [22] 1970 Attorney-Augustus G. Douvas, William J. Newman [21] Appl. No.: 102,720 and Norton Lesser 52] US. Cl ..1 ..91/346, 91/342 [57] ABSIMCT [51] Int. Cl. ..F0ll 31/02, FlSb 13/04 The following specification describes an air; motor Field of Search ..91/342, 344, 3 7, 3 337 formed of three coaxial cylinders or housings assembled by a simple threading operation with one end [56] References Clted housing having a spring biased valve assembly UNITED STATES PATENTS detachably inserted therein for directing air to op- I posite piston sides. A shuttle in one housing con- 2,215,852 Klell'l 342 X troning the valve assembly is a leeve bear- ..L iing to wear and a conduit transmitting air 2,637,304 5/1953 Dinkelkamp ..91/346 X from the valve assembly to the opposite end h i is 2,707,456 5/1955 Schwexsthal ..91/ 342 X Simply connected by a single pair f fitti g 2,740,384 4/1956 Dinkelkamp et al. ..91/337 2,745,387 5/1956 Dinkelkamp ..91/342 X 1 Claim, 8 Drawing Figures ALI (1 &

PATENT ED110124 m2 lmm INVENTOR Joseph M. SYomper By (MW Aflornev PATENTED um 24 I972 SHEET 2 [1F 3 INVENTOR Joseph M. Sfomper 4 PM AT Tornev FIG.3

PATENTEDnm 24 m2 SHEET 3 [1F 3 m v Attornev INVEN TOR Joseph M. Stomper AIR Moron BACKGROUND OF THE INVENTION Air motors such as typified in U.S. Pat. No.

2,637,304 incorporate a valve operator or shuttle for tripping a slide valve from one limit position to another as the piston approaches each end of its stroke. The slide valve in respective limit positions connects the air supply to respective opposite piston sides for reciprocating the piston. The valve operator is snapped to its limit position by a pair of snap acting spring toggle assemblies which create a large eccentric load on the valve operator, which in turn slides on the piston rod so that the inner or smaller surface of the valve operator bears the load. The valve operator or shuttle, therefore, tends to wear relatively quickly.

In addition, the slide valve is located in an internal chamber at one end of the piston cylinder where it is inaccessible without major disassembly of the motor and conduit that passes air between the valve and the piston side remote from the valve. A relatively complicated and expensive arrangement, therefore, results which requires relatively complicated and time consuming assembly procedures for replacement or repair.

SUMMARY OF THE INVENTION The present invention proposes an improvement in the described air motor by providing a valve assembly which is inserted through a wall passageway from exterior of the air motor and clamped in position by several bolts so that the valve assembly may be replaced or repaired without disassembling the motor. An outwardly extending rib on the valve assembly has a passageway axially aligned with an exterior conduit transmitting air to the side of the piston remote from the valve assembly to reduce the number of fittings or couplings. The valve operator or shuttle is supportedalong its exterior surface by a bearing sleeve to provide greater load distribution and minimize wear.

Further improvements in the air motor are provided by constructing the motor in three coaxially aligned shells or housings which are engaged by means of threads to couple the air motor into a unitary structure with the minimum of parts and labor.

Accordingly, it is a primary object of the present invention to provide an improved and more economical air motor.

It is another object of the present invention to provide a more durable air motor capable of facile servicmg.

Other objects and features of the present invention will become apparent on examination of the following specification and claims together with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view of the air motor incorporating the principles of the present invention;

FIG. 2 is a sectional view taken along the line 22 in FIG. 1;

FIG. 3 is a top elevational view of the air motor seen in FIG. 1;

FIG. 4 is a sectional view taken along the line 4-4 in FIG. 3;

FIG. 5 is a partial sectional view illustrating the connection of the valve assembly to the air motor;

FIG. 6 is an isometric view of the shuttle valve assembly;

FIG. 7 is a rear elevational view of the cylindrical member of the valve assembly; and

FIG. 8 is a sectional view taken along the line 8-8 in FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1 an air motor is indicated generally by the reference character 10. The motor 10 includes a piston or air cylinder or chamber 12 seen in FIGS. 2 and 4 and defined by central annular shell 14 having threads at opposite ends. One end of the chamber 12 is closed by a second shell or housing 16 threadingly engaging threads at one end of shell 12 and a third shell or housing 18 closes the opposite end of chamber 12. A ring nut 20 having an internal shoulder engaging an external shoulder on housing 18 is threaded on the opposite end of shell 14 to clamp the housing 18 to shell 14. Ring seals 22 are provided between the shell 14 and each

housing

16 and 18 to prevent leakage. v

A conventional piston 24 is adapted to be reciprocated in chamber 12 between the

housings

16 and 18. A trip rod 26 and a piston rod 28 project in respective directions along the central axis of the piston 24 into a respective central passageway '30 inhousing 16 as seen in FIGS. 2 and 4, and a respective central passageway 32 in housing 18. One end of piston rod 28 is secured to piston 24 by means of a nut 33 and is sealed in passageway 32 by a packing 34 to prevent air leakage from chamber 12. The other end of the rod 28 is accessible from the exterior of housing 18 and is threaded or otherwise formed to enable the piston rod of a pump, for example, to be connected thereto for operation by the air motor. A central cavity 35 is provided in rod 28 for receiving a reduced diameter portion 35a at one end of rod 26 and a cap 35b secured to the end of the reduced portion 35a.

Rod 26 in central passageway 30 is also sealed against leakage by a sealing assembly 36 and the passageway 30 is closed at its upper end by a plate 38 secured thereto by bolts 29. A cap 40 is secured to a reduced diameter portion at the upper end of rod 26 to provide a pair of spaced

shoulders

41 and 42 for engaging respective shoulders 44 and 46 formed on the internal surface of a shuttle 48.

The shuttle 48 is a generally annular sleeve sup ported for sliding axial movement along its external surface by axially spaced

bearing sleeves

50 and 51 secured in body 16. A pair of spaced

shoulders

52 and 54 are formed in the outer surface of shuttle 48 for engaging a slide valve 56 of a valve assembly 58 in response to reciprocation of the piston 24 to opposite ends of chamber 12 for the purpose of applying air under pressure to opposite piston sides, as will be explained. Air under pressure is supplied through a port 60 intermediate the ends of housing 16 and around shuttle 48 to the valve assembly 58.

A pair of spring loaded snap action toggle assemblies 62 such as described in the aforementioned patent are provided in housing 16 for the purpose of ensuring that the shuttle 48 moves the slide valve 56 to opposite limit positions as the piston 24 moves toward the end of its stroke. A toggle 64 for each assembly 62, having one end seated in a respective ball socket in shuttle 48, pressurizes a pair of coaxial springs 65 in the respective toggle assembly in response to movement of the piston and after the toggle is moved slightly past a position when they are coaxially aligned with the springs, the

springs release their stored energy to drive the shuttle to a limit position through the toggle and thereby ensure the valve 56 is moved to a limit position.

The valve assembly 58 is seated in a radial bore 66 of housing 16 opposite port 60 and controls the communication of inlet pressurized and exhaust air from port 60 to and from respective sides of piston 24. As seen in FIG. 6, the valve assembly 58 comprises a cylindrical member 68 having an annular recess 70 formed along the outer periphery adjacent one end thereof and a boss 72-formed thereon adjacent the same end.

Boss 72 has a pair of elongate straight parallel sides 74 and arcuate ends or sides 75 for nested engagement in a correspondingly shaped aperture 76 formed in a ring 78 that engages against the adjacent end of member 68. An O-ring 80 is seated in the recess 70 and is sandwiched between ring 78 and member 68 to seal the bore or passageway 66 against the leakage of air.

Three pair of passageways or

apertures

82, 84 and 86 are formed in boss 72 with a center pair 84 adapted to be either placed in communication with pair 82 or pair 86 by a recess 88 formed in one surface of slide valve 56. The valve 56 has parallel straight sides 90 and arcuate ends or sides 92 for alignment with respective sides of opening 76 of ring 78. The distance between arcuate sides 92 is less than the distance between the corresponding sides of aperture 76 so that the valve 56 may be slid between the arcuate ends of aperture 76 to place openings 84 in communication with opening 86 through recess 88 while leaving openings 82 in communication with central passageway 30 when the valve is at its upper position as seen in FIGS. 2 and 4. Alternatively, openings 84 .are placed in communication with openings 82 and openings 86 are in communication with central passageway 30 when the valve 56 is in its lower position.

The valve 56 is held in abutment with. boss 72 by a spring 94 which straddles the valve 56. A pair of depending legs 96 formed on spring 94 are secured to member 68 by means of screws such as 98 extending through apertures in ring 78 into threaded openings 99 in member 68 so that member 68, ring 78, O-ring 80, valve 56 and spring 94 form a subassembly 100 of assembly 58.

Subassembly 100 is clamped to a cap 102 by means of a pair of bolts 104 which extend through apertures in the cap 102, through respective apertures 106 in a sealing gasket 108 and into threaded openings 109 in member 68 to complete the assembly 58. Cap 102 with the gasket 108 are seated in an enlarged portion of bore 66 adjacent the outer wall of housing 16 with the gasket 108 seated against a radial wall 110 of bore 66 to seal the bore. Bolts 112 extending through openings 114 in gasket 108 secure the cap 102 and the assembly 58 t0 the housing 16 so that the entire assembly 58 may be disassembled from housing 16 by simply unscrewing bolts 1 12 accessible from the exterior of housing 16.

Cap 102 is provided with a central exhaust passageway or aperture 116 which communicates through an aperture 118 in gasket 108 and a passageway 120 formed in member 68 with the apertures 84 in boss 72. Opening 116 also extends through a boss 122 formed intermediate the ends of a rib 124 extending radially of bore 66 on the external surface of cap 102 and internal threads permit receipt of an ap' propriate fitting to carry away or muffle exhaust air. A second boss 126 formed at the lower end of the rib 124 has a passageway or opening 128 therein extending radially of bore 66 to receive a conduit 130. Opening 128 communicates with a passageway 132 extending axially of cap 102 and parallel to opening 116 and in turn communicates with a ring passageway or recess 134. Recess 134 is formed by a pair of spaced

ringshaped bosses

135 and 136 on the inner surface of cap 102 engaging gasket 108 with boss 135 encircling boss 136. Recess 134 in turn communicates with a passageway 138 in gasket 108, which in turn communicates with a passageway 140 formed in member 68 and in communication with apertures 86. I

Conduit 130 is sealed with O-ring 141 at one end in opening 128 and extends axially of piston 24 and rod 28 assembled toward housing 18. A nut 142 and conventional ferrule are provided at the opposite end of conduit 130 for threading engagement with an L- shaped fitting 144 projecting from a threaded radial passageway 146 in housing 18. Passageway 146 in turn communicates with a passageway 148 in housing 18 extending axially of piston 24 and opening into the piston chamber 12 for the purpose of communicating either inlet air to the lower side of the piston 24 or exhaust air therefrom.

Openings 82 in boss 72 communicate with-an axial passageway l50 and in turn communicating with a radial passageway 152 in member 68 for communication with a passageway 154 in housing 16. Passageway 154 extends axially of piston 24 and communicates with chamber 12 for the purpose of either passing inletair to the upper Side of piston 24 or exhaust air from the upper piston side.

Assuming the piston 24 is in the position shown in FIG. 2 and inlet air under greater than atmospheric pressure is applied from a source, not shown, through an appropriate fitting threaded in port 60, the operation of the air motor 10 will now be described. The inlet air is transmitted through an opening 156 in housing 16 aligned with port 60, the central passageway 30, apertures 82 in boss 72, passageway 152 in member 68 and passageway 154 to the upper side of piston 24 to thereby force the piston downwardly in chamber 12. The air on the lower side of the piston is simultaneously exhausted to atmosphere through passageway 148, fitting 144, conduit 130,

passageways

128 and 132, passageway or recess 134 in the inner surface of cap 102, opening 138 in gasket 108, passageway 140 in member 68, openings 86 in boss 72, recess 88 in valve 56, openings 84 in boss 72 and

passageways

120, 118 and 116 to atmosphere.

As the piston 24 moves downwardly a predetermined distance, the nut 33 engages shoulder 35c of cap 35b to move the trip rod 26. The shoulder 41 of cap 40 on rod 26 then engages shoulder 44 on shuttle 48 to move the shuttle downwardly with the annular shuttle being provided with bearing support along its outer surface by the

annular bearing sleeves

50 and 51. As the shuttle 48 moves down, the toggles 64 apply pressure to the springs 65 of toggle assemblies 62 and after the toggles 64 pass their axially aligned position with the springs 65, the spring pressure is released causing the toggles 64 to move the shuttle 48 independently of rod 26. The movement of shuttle 48 in response to the release of spring pressure engages shoulder 52 with valve 56 to rapidly shift the position of valve 56 to the opposite end of aperture 76 in ring 78 for the purpose of preventing any motor stalling as may occur in the event the valve slowly exposed both sets of

apertures

82 and 86 to inlet air.

With valve 56in its opposite limit position, apertures 86 are now exposed to inlet air under pressure and apertures 82 blocked therefrom. The inlet air is passed through aperture 86 and

passageways

140, 138, 134, 132 and 128 to conduit 130 through fitting 144 and passageway 148 to force the piston 24 upwardly. Simultaneously air is exhausted to atmosphere from the upper side of piston 24 through passageways 154, 152 and openings 82, the valve recess 88, openings 84, and

passageways

120 and 116.

As the piston 24 moves upwardly a predetermined distance, the nut 32 engages the shoulder between reduced diameter portion 35a and the normal diameter of rod 26 to carry rod 26 upwardly. The shoulder 42 on the rod 26 then engages shoulder 46 on the shuttle 48 to move the shuttle upwardly. As the shuttle 48 moves upwardly, the toggles 64 apply pressure against the springs 65 in toggle assemblies 62 to store energy therein and, as the toggles move past the axis of the springs, the springs release their energy to drive the shuttle 48 rapidly to its upper limit position. As the shuttle 48 moves into its upper limit position, shoulder 54 thereon throws the valve 56 back into the position shown in FIGS. 2 and 4, whereafter the piston 24 is caused to reverse its movement. Thus, the piston 24 is reciprocated to drive the rod 28 in respective directions and thereby operate a device such as a pump connected thereto. It will be appreciated, of course, that the motor can also be driven in response to the application of other pressurized fluids or the use of a vacuum.

lf replacement of one of the components of assembly 58 becomes necessary, the coupling 142 is simply disengaged from fitting 144 and the conduit 130 disengaged from passageway 128. The bolts 112 are disengaged from housing 16 and the cap 102 is grasped at rib 124 to facilely remove the assembly 58 from the housing 16. The malfunctioning component of assembly 58 may then be replaced or repaired as required by disengagement of bolts 98 and/or 104 and subsequent reassembly of assembly 58 into housing 16.

Access to the interior of shell 14 is easily provided by simply unthreading housing 16 from shell 14 after disassembly of conduit 128 and/or ring nut 20, which arrangement likewise permits facile reassembly.

The foregoing constitutes a description of an improved air motor whose inventive concepts are believed set forth in the accompanying claims.

What is claimed is:

1. An air motor comprising a shell defining a piston chamber, one housing threadingly engaged with said shell for closing one end of said shell to define one end of said chamber and having a pair of circumferentially spaced radial passageways therein with one of said radial passageways adapted to receive air under pressure, a piston in said chamber movable in opposite directions, a second housing, means for threadingly engaging said second housing with said shell for closing the other end of said shell to define a respective other end of said chamber, a piston rod for said piston extending axially into said one housing, a valve, a member received in the other radial passageway of said one housing and having three passageways therein with one member passageway located intermediate the other member passageways, a ring seated against one face of said member with said ring having an opening therein for receiving said valve in abutment with one face ofsaid member, said ring opening having one pair of spaced sides defining a guideway for said valve and another pair of spaced sides each defining a respective limit position for said valve, a plate spring having a flat face overlappingly engaged with said valve, screw means securing said spring and ring to said member for holding said ring in abutment with said member and said valve movably engaged with said member one face to select one of said other member passageways for communication with said one member passageway and the other of said other member passageways for communication with said one housing one radial passageway in accordance with the limit position to which said valve is moved, an O-ring seated between said member and ring and engaging the periphery of said one housing other radial passageway for sealing said other radial passageway against the passage of air, a cap overlapping said one housing other radial passageway having a pair of cap passageways therein with one of said cap passageways aligned with said member one passageway and the other cap passageway aligned with a respective one of said other memberpassageways, said cap one passageway adapted to communicate said member one passageway with atmosphere, a single sealing means overlapping said one housing other radial passageway interposed between said member and said cap and having means communicating said one cap passageway with said one member passageway and said other cap passageway with said respective one of said other member passageways, means securing said cap to said member, a plurality of bolts threaded into said housing and extending through said cap and sealing means for sealingly securing said cap and member to said housing with said one cap passageway in communication with said one member passageway and said other cap passageway in communication with said respective one of said other member passageways, an axially extending passageway in said one housing communicating said one end of said piston chamber with the other of said member other passageways, a passageway in said second housing in communication with said respective other chamber end, a conduit having one end inserted into said other cap passageway, a pair of serially connected fittings for connecting the other end of said conduit to said second housing passageway to communicate said chamber other end with said other cap passageway and the respective one of said member other passageways, a shuttle relatively movably mounted on said piston rod and movable with said piston rod and engaging said valve, a snap acting spring toggle assembly for driving said shuttle to a 8 V passageways while the other of said other member passageways is in communication with air under pressure from said one housing one radial passageway, and

a sleeve in said one housing encircling said shuttle to provide a bearing surface for said shuttle.

Claims

1. An air motor comprising a shell defining a piston chamber, one housing threadingly engaged with said shell for closing one end of said shell to define one end of said chamber and having a pair of circumferentially spaced radial passageways therein with one of said radial passageways adapted to receive air under pressure, a piston in said chamber movable in opposite directions, a second housing, means for threadingly engaging said second housing with said shell for closing the other end of said shell to define a respective other end of said chamber, a piston rod for said piston extending axially into said one housing, a valve, a member received in the other radial passageway of said one housing and having three passageways therein with one member passageway located intermediate the other member passageways, a ring seated against one face of said member with said ring having an opening therein for receiving said valve in abutment with one face of said member, said ring opening having one pair of spaced sides defining a guideway for said valve and another pair of spaced sides each defining a respective limit position for said valve, a plate spring having a flat face overlappingly engaged with said valve, screw means securing said spring and ring to said member for holding said ring in abutment with said member and said valve movably engaged with said member one face to select one of said other member passageways for communication with said one member passageway and the other of said other member passageways for communication with said one housing one radial passageway in accordance with the limit position to which said valve is moved, an O-ring seated between said member and ring and engaging the periphery of said one housing other radial passageway for sealing said other radial passageway against the passage of air, a cap overlapping said one housing other radial passageway having a pair of cap passageways therein with one of said cap passageways aligned with said member one passageway and the other cap passageway aligned with a respective one of said other member passageways, said cap one passageway adapted to communicate said member one passageway with atmosphere, a single sealing means overlapping said one housing other radial passageway interposed between said member and said cap and having means communicating said one cap passageway with said one member passageway and said other cap passageway with said respective one of said other member passageways, means securing said cap to said member, a plurality of bolts threaded into said housing and extending through said cap and sealing means for sealingly securing said cap and member to said housing witH said one cap passageway in communication with said one member passageway and said other cap passageway in communication with said respective one of said other member passageways, an axially extending passageway in said one housing communicating said one end of said piston chamber with the other of said member other passageways, a passageway in said second housing in communication with said respective other chamber end, a conduit having one end inserted into said other cap passageway, a pair of serially connected fittings for connecting the other end of said conduit to said second housing passageway to communicate said chamber other end with said other cap passageway and the respective one of said member other passageways, a shuttle relatively movably mounted on said piston rod and movable with said piston rod and engaging said valve, a snap acting spring toggle assembly for driving said shuttle to a respective limit position in response to said shuttle being moved to a respective predetermined position by said piston rod for moving said valve to opposite limit positions for communicating said one member passageway with a respective one of said other member passageways while the other of said other member passageways is in communication with air under pressure from said one housing one radial passageway, and a sleeve in said one housing encircling said shuttle to provide a bearing surface for said shuttle.