WO2012037580A2 - Rotary air motor locking assembly - Google Patents

Abstract

A rotary vane air motor locking assembly comprises an annular stator housing, first and second end plates, a rotor vane assembly and a locking mechanism. The stator housing extends between first and second axial ends to define a rotor pocket. The first and second end plates are disposed at the first and second axial ends of the stator housing, respectively. The rotor vane assembly is disposed in the rotor pocket and comprises a rotor having an axis of rotation, a plurality of slots disposed within the rotor and a plurality of vanes disposed within the plurality of slots. The locking mechanism is coupled to the second end plate to selectively immobilize rotation of the rotor vane assembly within the annular stator housing by engaging the rotor vane assembly.

Description

ROTARY AIR MOTOR LOCKING ASSEMBLY

BACKGROUND

The present invention relates generally to a chopper device that distributes fiber material into a stream of resin material dispensed from a spray gun. In particular, the present invention relates to a locking assembly that prevents rotation of a chopper head within the chopper device.

Chopper guns are frequently used in the composite material industry to form large, shaped products, such as in the marine and watercraft industries and pool and spa industries. Chopper guns comprise assemblies of a fiber chopper and a liquid spray gun. Compressed air is typically supplied to the chopper gun to power a pumping mechanism in the spray gun and an air motor in the fiber chopper. The spray gun typically receives a liquid resin material and a liquid catalyst material. Actuation of a trigger on the gun dispenses the materials into a mix chamber before being sprayed out of a nozzle of the gun. Mixing of the catalyst with the resin begins a solidification process, which eventually leads to a hard, rigid material being formed upon complete curing of the materials. The fiber chopper is typically mounted on top of the spray gun and actuated by the trigger. The fiber chopper receives rovings of a fiber material, such as fiberglass, which passes between an idler wheel, an anvil and a cutter blade head. In many configurations, the cutter head is mounted on a drive shaft of the air motor, while the anvil is freely rotatable on a post. The fiber rovings are cut into small segments between the anvil and cutter blade head while being propelled out of the chopper by rotation of the anvil and the cutter blade head by the air motor. The segments of fiber are mixed into the sprayed mixture of resin and catalyst such that the final cured product is fiber reinforced.

The cutter blade head and anvil of the fiber chopper include consumable pieces that must be replaced after a threshold wear level is surpassed. For example, the blade head typically includes a plurality of razor blades inserted into slots on a blade wheel. Also, the anvil includes a roller of soft material into which blades of the cutter blade head penetrate while slicing or chopping the fiber roving. Thus, it is frequently necessary to disassemble the fiber chopper, remove the cutter blade head from the drive shaft, remove the anvil from the post, remove the roller from the anvil and remove each razor blade of the cutter blade head. Removal of the razor blades from the cutter blade head sometimes involves turning a knob of a quick-release mechanism. However, the drive shaft of the air motor freely rotates when not in operation, thus leaving both the cutter blade head and the anvil free to rotate within the air motor. Free rotation of the cutter blade head makes turning the quick-release mechanism difficult. This renders replacement of the razor blades a potentially hazardous operation. There is, therefore, a need for improving safety of rotary air motor assemblies, particularly when changing consumable pieces.

SUMMARY

The present invention is directed to a rotary vane air motor locking assembly such that can be used in a hand-held power tool. A rotary vane air motor locking assembly comprises an annular stator housing, first and second end plates, a rotor vane assembly and a locking mechanism. The stator housing extends between first and second axial ends to define a rotor pocket. The first and second end plates are disposed at the first and second axial ends of the stator housing, respectively. The rotor vane assembly is disposed within the rotor pocket and comprises a rotor having an axis of rotation, a plurality of slots disposed within the rotor and a plurality of vanes disposed within the plurality of slots. The locking mechanism is coupled to the second end plate to selectively immobilize rotation of the rotor vane assembly within the annular stator housing by engaging the rotor vane assembly.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded view of a hand-held power tool comprising a liquid spray gun and a fiber roving chopper assembly in which an air motor of the present invention is used.

FIG. 2 is a perspective view of the air motor of FIG. 1 showing a rotary speed control housing surrounding a stator housing in which a locking assembly of the present invention is incorporated.

FIG. 3 is an exploded view of the air motor of FIG. 2 in which the rotary speed control housing is removed from the stator housing to show a rotor vane assembly and a locking assembly.

FIG. 4 is a side cross sectional view of the air motor of FIG. 2 showing the rotary speed control housing and the stator housing surrounding the rotor vane assembly and the locking mechanism.

FIG. 5 is an end cross sectional view of the air motor taken at section 5-5 of FIG. 4 to show an eccentric position of the rotor vane assembly within a rotor pocket of the stator housing.

FIG. 6 is a close-up perspective view of the locking mechanism of FIG. 4 showing a stop having a knob, a flange and a lug. DETAILED DESCRIPTION

FIG. 1 is an exploded view of a hand-held power tool assembly of liquid spray gun 10 and fiber roving chopper 12 in which air motor 14 of the present invention may be used. In FIG. 1, fiber roving chopper 12 is shown slightly enlarged with respect to liquid spray gun 10. Liquid spray gun 10 comprises a two component internal mixing gun having handle 16, valve body 18, nozzle 20 and trigger 22. Fiber roving chopper 12 includes air motor 14, housing 24 and cover 26. Valve body 18 of spray gun 10 includes valve assembly 28, air inlet 30A, material inlet 32, catalyst inlet 34 and air outlet 36. Housing 24 of fiber roving chopper 12 includes fiber inlet 38, including openings 40, tensioning device 42, hard stop 44, fasteners 46 A and 46B and knob 48. Cover 26 includes dispenser chute 50.

In the embodiment shown, spray gun 10 comprises a two component mixing gun that receives two liquid components that mix when dispensed to produce a mixture that cures into a hardened material. A first component comprises a resin material, such as a polyester resin or a vinyl ester, and is fed into valve body 18 at material inlet 32. A second component comprises a catalyst material that causes the resin material to harden, such as Methyl Ethyl Ketone Peroxide (MEKP), and is fed into valve body 18 at catalyst inlet 34. Material inlet 32 and catalyst inlet 34 feed materials, respectively, into valves seated within valve body 18 and connected to valve assembly 28. Other inlets, such as inlet 30B, are provided to gun 10 for other fluids such as a solvent. Actuation of trigger 22 simultaneously causes valves of valve assembly 28 to open and causes pressurized components to flow into nozzle 18. As shown, spray gun 10 comprises an internal mixer where the two components are pressurized at inlets 32 and 34 by an external source (such as a pressurized fluid tank not shown) and mixed within tube 52 before entering nozzle 20. Pressurized air may also be provided to nozzle 20 to shape or direct the mixed flow stream. In other embodiments, an external mix gun is used where the materials are mixed outside of gun 10.

Fiber roving chopper 12 is face-mounted to air motor 14. Pressurized air from air inlet 30A is fed through valve body 18 to outlet 36, which connects to inlet ports 104 (FIG. 3) on air motor 14 of fiber chopper 12. Rovings or strands of a fiber material, such as fiberglass, are fed into cover 26 through openings 40 in fiber inlet 38. Activation of air motor 14 by actuation of trigger 22 causes the rovings to be pulled into a cutter blade head by an anvil head and idler wheel mounted on housing 24 within cover 26, as is discussed in greater detail in PCT application Serial No. PCT/2010/003029, entitled "CUTTER BLADE HEAD FOR FIBER ROVING CHOPPER," filed November 23, 2010 by inventors James H. Rohrer and Jonathan R. McMichael, the contents of which are incorporated by this reference. The chopped roving pieces are expelled from dispenser chute 50 into the mixed stream of resin and catalyst materials from nozzle 20 such that the hardened material includes fiber reinforcements that increase strength of the final product. Roving chopper 12 can accommodate different sized rovings and can chop the rovings into different sized pieces by adjusting tensioning device 42 and hard stop 44, as is discussed in greater detail in PCT application Serial No. PCT/2011/001572, entitled "ADJUSTABLE TENSIONING DEVICE FOR FIBER ROVING CHOPPER," filed September 13, 2011 by inventors Corey D. Johnson and Jonathan R. McMichael, the contents of which are incorporated by this reference.

Air motor 14 includes a rotary speed control and muffler assembly that adjusts the flow of compressed air through air motor 14 to vary the speed of a rotor vane assembly within air motor 14, as is discussed in greater detail in PCT application Serial No. PCT/2011/001574, entitled "ROTARY AIR MOTOR SPEED CONTROL ASSEMBLY," filed September 13, 2011 by inventor Corey D. Johnson, the contents of which are incorporated by this reference. Air motor 14 of the present invention includes a stop or locking mechanism that prevents rotation of the rotor vane assembly within air motor 14. Although the present invention is described herein with reference to fiber roving chopper 12, air motor 14 and the locking mechanism therein can be used in other applications.

FIG. 2 is a perspective view of air motor 14 of FIG. 1 showing muffler assembly 54 extending from rotary speed control housing 56 surrounding stator housing 58. Rotary speed control housing 56 comprises an annular body having rim 60. Muffler assembly 54 includes housing 62, fasteners 64 and keyway slots 66. Stator housing 58 includes mounting plate 68, bearing pocket 70 and mounting bores 72. Drive shaft 74A of a rotor vane assembly extends from within stator housing 58 through front bearing 76. Housing 62 of muffler assembly 54 is secured to housing 56 at the location of exhaust slots (FIG. 3) extending through housing 56 via a plurality of threaded fasteners 64 or any other suitable means. Air distributed to air motor 14 from outlet 36 (FIG. 1) drives air motor 14 before exiting at keyway slots 66 of muffler assembly 54.

Stator housing 58 comprises an annular body that extends into housing 56.

Rotary speed control housing 56 is rotatably adjustable about stator housing 58. As discussed with reference to FIG. 5, housing 56 and housing 58 are eccentric, that is to say they are not concentric. Rim 60 provides structural support to housing 56 and a place to grip housing 56 when rotating about housing 58. Drive shaft 74A extends through mounting plate 68, which is machined integrally from housing 58, to join with housing 24 of roving chopper 12 (FIG. 1). Within housing 58, shaft 74A connects to a rotor vane assembly (FIG. 3), which is supported by front bearing 76 within mounting plate 68 and by a rear bearing assembly supported radially inward of rim 60. Rotary speed control housing 56 adjusts the location of muffler assembly 54 with respect to exit slots (FIG. 3) in stator housing 58 to control the speed at which the rotor vane assembly rotates within housing 58. Muffler assembly 54 is configured to dampen the exhausted air as it expands and is situated so as to direct the air away from an operator of chopper 12. Stator housing 58 includes a locking mechanism of the present invention that prevents the rotor vane assembly from rotating within air motor 14, as shown in FIG. 3.

FIG. 3 is an exploded view of air motor 14 of FIG. 2 in which rotary speed control housing 56 is removed from stator housing 58 to show front bearing 76, end cap 78, rotor vane assembly 80, bearing cap 82, locking mechanism 84 and rear bearing 86. Rotary speed control housing 56 includes rim 60 and exhaust port 88. Stator housing 58 includes mounting plate 68, end cap 78, annular portion 89, exit slots 90A and 90B and end wall portion 91. Rotor vane assembly 80 comprises drive shaft 74A, stub shaft 74B, rotor 92 and vanes 94. Muffler assembly 54 includes housing 62, fasteners 64, slots 66 and muffler baffles 96. Locking mechanism 84 includes seal 97, stop 98, spring 100 and washer 102.

Muffler housing 62 is coupled to rotary speed control housing 56 at exhaust port 88 via threaded fasteners 64. Baffles 96 are positioned within housing 62 between exhaust port 88 and slots 66. Rotary speed control housing 56 is positioned around stator housing 58 so that exhaust port 88 aligns with exit slots 90A and 90B. Front bearing 76 is positioned within bearing pocket 70, and rear bearing 86 is positioned within bearing cap 82. Bearing cap 82 includes bearing pocket 101 in which bearing 86 is positioned. In one embodiment, bearing 76 is press fit into pocket 70 and bearing 86 is press fit into cap 82. Rotor vane assembly 80 is positioned within stator housing 58 such that drive shaft 74A is supported within front bearing 76, stub shaft 74B is supported in rear bearing 86 and rotor 92 is disposed within annular portion 89. End cap 78 couples to annular portion 89 to hold rotor vane assembly 80 and locking mechanism 84 together with air motor 14. Specifically, rotor vane assembly 80 is supported by bearings 76 and 86. Stop 98 of locking mechanism 84 is positioned between end cap 78 and washer 102, which is positioned against bearing cap 82. With end cap 78 coupled to annular portion 89, spring 100 pushes stop 98 away from bearing cap 82 and stub shaft 74B. Stop 98 includes a flange that abuts an opening within end cap 78 to prevent stop 98 from being pushed out of end cap 78. An operator pushes stop 98 to compress spring 100 and push a lug on stop 98 into a mating socket in stub shaft 74B. Mounting plate 68 permits housing 58 to be coupled to housing 24 of chopper 12 (FIG. 1). For example, mounting surface 103 is flat for mating flush with housing 24. Compressed air is provided to air motor 14 through inlet ports 104 in end wall 91 of stator housing 58. O-ring seal 106 seals between mounting plate 68 and housing 24, and O-ring seal 97 seals between stop 98 and end cap 78. Inlet ports 104 extend from openings in housing 24 through to the interior of housing 58. The compressed air induces rotation of rotor 92 by asserting pressure against vanes 94. Specifically, rotor 92 is eccentrically positioned within housing 58, as is known in the art, to produce pressure differentials across vanes 94. Vanes 94 slide in and out of slots 105 (FIGS. 3 & 4) within rotor 92 due to the eccentricity of rotor 92 within the bore of annular portion 89. The compressed air exits stator housing 58 at exit slots 90A and 90B. Rotary speed control housing 56 is rotated on stator housing 58 to adjust the position of exhaust port 88 with respect to exit slots 90A and 90B to control the speed of rotor vane assembly 80, as is discussed in greater detail in the aforementioned PCT application to Johnson. From exhaust port 88, the compressed air travels into muffler housing 62 and passes through baffles 96 and slots 66 to dampen sound produced by expansion of the compressed air.

Annular portion 89 extends axially from end wall portion 91 to form U- shaped body. Annular portion 89 extends between end wall portion 91 and end cap 78 to form a rotor pocket for receiving rotor vane assembly 80. The rotor pocket is closed off by end cap 78 and end wall portion 91, save for openings to permit access to locking mechanism 84 and drive shaft 74A, respectively. These openings are sealed by seal 106 on mounting plate 68 and seal 97 on stop 98. Stator housing 58 and end cap 78 provide mating surfaces that rotor 92 and vanes 94 engage during operation of air motor 14. Construction of end cap 78, annular portion 89 and end wall portion 91 are discussed in co-pending application entitled "ROTARY AIR MOTOR HOUSING ASSEMBLY" filed on the same day herewith by inventors Corey D. Johnson, Jonathan R. McMichael and Steven R. Sinders.

FIG. 4 is a side cross sectional view of air motor 14 taken at section 4-4 of FIG. 5 to show rotary speed control housing 56 and stator housing 58 surrounding rotor vane assembly 80 and locking mechanism 84. FIG. 5 is an end cross sectional view of air motor 14 taken at section 5-5 of FIG. 4 to show the eccentric position of rotor vane assembly 80 within stator housing 58. FIGS. 4 and 5 are discussed concurrently.

With reference to FIG. 4, rotary speed control housing 56 comprises an annular body having outer surface 108 and inner surface 110, into which stator housing 58 is inserted. Annular portion 89 of stator housing 58 has outer surface 112 that fits against inner surface 110, and inner surface 114 that forms rotor pocket 115 into which rotor vane assembly 80 is inserted. Inner surface 110 of housing 56 includes grooves 116A and 116B into which seals 118A and 118B are positioned to seal against housing 58. Seals 118A and 118B comprise O-rings that permit slippage of housing 56 against housing 58 while preventing air leakage between the two bodies. Speed control housing 56 fits firmly around stator housing 58 so that the position of housing 56 will not freely move during operation of air motor 14 without an externally applied force, such as from an operator of air motor 14.

End wall portion 91 comprises a disk or plate that joins inner surface 114 within pocket 115 and that joins outer surface 112 outside of pocket 115 to close off rotor assembly 80 within pocket 115. Mounting plate 68 comprises a rectilinear, axial extension of end wall portion 91, but may have other cross- sectional profiles. Shaft bore 120 extends through end wall portion 91 and mounting plate 68 along rotational axis RA of rotor 92. Bearing pocket 70 comprises a counterbore surrounding shaft bore 120 to receive front bearing 76. Bearing pocket 70 extends through the thickness of mounting plate 68 and into end wall portion 91. Bearing pocket 70 includes groove 122 for receiving seal 106.

End cap 78 comprises end plate 124, annular flange 126 and locking pocket 128. End plate 124 and annular flange 126 close off rotor assembly 80 within pocket 115 inside annular portion 89. Specifically, annular flange 126 engages annular portion 89 along threaded engagement 130. In one embodiment, annular portion 89 includes male threads and flange 126 includes female threads. Threaded engagement 130 extends across less than the width of annular flange 126 such that end plate 124 does not contact annular portion 89. The inner diameter surface of annular flange 126 thus contacts outer surface 112 of annular portion 89 along a mating interface. End cap 78 and housing 58 engage each other along only a single mating interface to minimize tolerance stack-up and the like.

As previously mentioned, locking mechanism 84 is disposed within pocket

128 of end cap 78. Specifically, stop 98 comprises knob 132, flange 134 and lug 136. Knob 132 extends through bore 137 in pocket 128 to provide access for an operator of air motor 14. Flange 134 engages mating flange 138 of pocket 128 within cap 78. Flange 134 includes a channel for receiving O-ring seal 97. Washer 102 is disposed within counterbore 140 in cap 78. Counterbore 140 is disposed in end plate 124 of cap 78 so that washer 102 and end plate 124 both flushly engage bearing cap 82. Spring 100 is disposed around lug 136 and within flange 134 so as to apply spring force between knob 132 and washer 102. Flange 134 prevents stop 98 from being pushed out of bore 137. The inner diameter of washer 140 is larger than lug 136, but smaller than the diameter of spring 100. In the state shown in FIG. 4, lug 136 extends from knob 132 so as to fall short of contacting stub shaft 74B. In the particular embodiment shown, lug 136 penetrates washer 140, but need not extend that far. Stub shaft 74B includes anti-rotation socket 142 into which lug 136 is inserted when an operator pushes knob 132 to overcome the force of spring 100, thus preventing rotation of rotor 92.

Rotor 92 of rotor vane assembly 80, including shafts 74A and 74B, extends axially from locking mechanism 84 to the outside of housing 58. Stub shaft 74B is disposed concentrically within rear bearing 86 and bearing cap 82. Drive shaft 74A is disposed concentrically within front bearing 76 and bearing pocket 70. Bearings 76 and 86 comprise any known bearings that are typically used in the art, such as ball bearings. Bearing cap 82 is positioned within shoulder 143 of stator housing 58. Rotor 92 contacts bearing cap 82 and end wall portion 91, and is configured to rotate within pocket 115. Vanes 94 are inserted into slots 105 (FIG. 5) within rotor 92. Compressed air is introduced into inlet ports 104 (FIG. 5) to cause rotor 92 to rotate within inner surface 114 by producing a pressure differential across vanes 94. Springs 144 maintain vanes 94 biased out of slots 105 toward surface 114. Vanes 94 slide in and out of slots 105 as rotor 92 rotates within housing 58. Compressed air introduced into rotor pocket 115 prevents operation of locking mechanism 84 while air motor 14 is operating. Specifically, pocket 128 is in fluid communication with rotor pocket 115 such that the compressed air pushes against flange 134 and knob 132 to force stop out of pocket 128. Seal 97 prevents leakage of the compressed air and permits building of forces from the compressed air within pocket 128. Without the force of the compressed air, knob 132 can be displaced to push lug 136 into socket 142.

With reference to FIG. 5, speed control housing 56 comprises an annular cylinder having outer surface 108. Inner surface 110 extends into the cylinder to form a bore for receiving stator housing 58. The center of inner surface 110 is offset from the center of outer surface 108 such that surfaces 108 and 110 are eccentric. As discussed with reference to FIG. 3, a passage extends through housings 56 and 58 to connect the interior of air motor 14 to muffler assembly 54. Stator housing 58 comprises an annular cylinder having outer surface 112. Inner surface 114 extends into the cylinder to form a bore comprising pocket 115 for receiving rotor vane assembly 80. The center of inner surface 114 is offset from the center of outer surface 112 such that surfaces 112 and 114 are eccentric. Such eccentricity is a feature of rotary vane air motors, as is known in the art. The center of rotor 92, about which rotor vane assembly 80 rotates, is concentric with outer surface 112 of housing 58 and inner surface 110 of housing 56 along rotational axis RA. Compressed air enters housing 58 through inlet ports 104 and pressurizes the area behind vane 94A. The increase in pressure behind vane 94A causes vane 94A and rotor 92 to rotate counter-clockwise with reference to FIG. 5. As vane 94A rotates, it extends further from slot 105 A under force of spring 144. At the same time, the space between rotor 92 and inner surface 114 increases, decreasing the pressure in front of vane 94A. As such, rotor 92 is caused to continuously rotate counter-clockwise. Once vane 94A reaches muffler assembly 54, the compressed air escapes air motor 14 at keyway slots 66. O-ring 106 and O-ring 97 seal the air path between inlet ports 104 and exit slots 90 A and 90B. For example, compressed air is able to pass through, or blow by, bearings 76 and 86. O-rings 106 and 97 prevent leakage of the air and improve the efficiency of air motor 14.

FIG. 6 is a close-up perspective sectional view of locking mechanism 84 of FIG. 4 showing stop 98 having knob 132, flange 134 and lug 136. Stop 98 is disposed within locking pocket 128, which is attached to end plate 124. End plate 124 includes counterbore 140 in which washer 102 is seated. Locking pocket 128 comprises annular pocket wall 146 that extends axially from end plate 124 within counterbore 140. Retention flange 138 extends radially inward from pocket wall 146 to form bore 137. Stop 98 is disposed within pocket 128 such that knob 132 extends through bore 137 and lug 136 extends towards counterbore 140. Flange 134 engages pocket wall 146 within pocket 128 and includes channel 148 for receiving O-ring seal 97. Lug 136 includes chamfer 150 and facets 152A, while anti-rotation socket 142 includes facets 152B.

As discussed, during operation of air motor 14, compressed air forces stop 98 into pocket 128 (to the left in FIG. 6). This feature prevents engagement of lug 136 with socket 142 while rotor 92 is spinning, thereby preventing shearing of lug 136. As such, lug 136 is not designed as a brake mechanism for rotor 92. If locking mechanism 84 is actuated such that lug 136 is engaged with socket 142 while operation of air motor 14 is initiated, the forces generated by the compressed air will push stop 98 into pocket 128. Similarly, the force of the compressed air will prevent lug 136 from leaving pocket 128 while air motor 14 is operation. In other words, the force against stop 128 generated by the compressed air is greater than can typically be overcome by a mechanically unaided operator. The internal surface areas of stop 98, such as on knob 132 and flange 134, are sized in relation to the magnitude of the pressure of compressed air supplied to rotor pocket 115 to achieve this result. Additionally, O-ring seal 97 assists in the compressed air achieving adequate force against stop 98.

Locking mechanism 84 is designed to hold rotor 92 stationary after rotation has ceased. Lug 136 comprises a stud or shaft that is retractably extended into socket 142. Knob 132 is pushed into pocket 128 (to the right in FIG. 6) so that lug 136 engages stub shaft 74B. Facets 152A of lug 136 provide lug 136 with a locking cross-sectional profile that mates with facets 152B of socket 142. Specifically, facets 152B absorb torque applied to lug 136 through facets 152A. As such, rotation applied to rotor 92 by an operator when changing razor blades in the cutter blade head is balanced by engagement of facets 152A and 152B. In the embodiment shown, facets 152A form a hexagonal locking profile. Other embodiments may also be used such as square, rectangular or octagonal locking profiles. Chamfer 150 allows insertion of lug 136 into socket 142 without the need for facets 152A to be aligned with facets 152B. Specifically, chamfer 150 allows lug 136 to be partially inserted into socket 142 to induce alignment of facets 152A with facets 152B. Once inserted, socket 142 and lug 136 form a pair of broached male and female keys that inhibit rotation of rotor vane assembly 80 so that consumable pieces or components of chopper device 12 can be safely removed and replaced.

Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.

Claims

CLAIMS:

1. A rotary vane air motor locking assembly comprising:

an annular stator housing extending from a first axial end to a second axial end to define a rotor pocket;

first and second end plates disposed at the first and second axial ends of the annular stator housing, respectively;

a rotor vane assembly disposed within the rotor pocket and comprising: a rotor having an axis of rotation;

a plurality of slots disposed within the rotor; and a plurality of vanes disposed within the plurality of slots; and a locking mechanism coupled to the second end plate to selectively immobilize rotation of the rotor vane assembly within the annular stator housing by engaging the rotor vane assembly.

2. The rotary vane air motor locking assembly of claim 1 wherein:

the rotor vane assembly comprises:

a drive shaft extending from the rotor toward the first end plate along the axis of rotation; and

a stub shaft extending from the rotor toward the second end plate along the axis of rotation; and

the locking mechanism comprises:

a retractable stud coupled to the second end plate along the axis of rotation; and

a spring coupled to the second end plate to bias the retractable stud away from the stub shaft.

3. The rotary vane air motor locking assembly of claim 2 wherein the stub shaft comprises a socket extending into the stub shaft aligned with the retractable stud.

4. The rotary vane air motor locking assembly of claim 3 wherein:

the stud includes a locking cross-sectional profile; and

the socket includes a cross-sectional profile configured to mate with the locking cross-sectional profile of the stud.

5. The rotary vane air motor locking assembly of claim 3 wherein the locking mechanism further comprises:

a knob joined to the retractable stud and extending through the second end plate, the knob being displaceable to overcome the spring and push the stud into the socket.

6. The rotary vane air motor locking assembly of claim 5 wherein the second end plate comprises:

a bore extending through the second end plate along the axis of rotation through which the knob extends;

an annular pocket wall surrounding the bore on an exterior of the second end plate; and

a flange extending from the annular pocket wall toward the axis of rotation.

7. The rotary vane air motor locking assembly of claim 6 wherein surface areas of the flange and the knob are sized such that compressed air applied to the rotor pocket during operation of the rotor vane assembly applies a force against the locking mechanism to prevent displacement of the retractable stud.

8. The rotary vane air motor locking assembly of claim 6 wherein the locking mechanism further comprises:

a washer disposed between the second end plate and the annular stator housing to bias the spring away from the rotor.

9. The rotary vane air motor locking assembly of claim 7 wherein the locking mechanism further comprises:

a flange extending from the knob to engage the annular pocket wall;

a channel disposed within the flange; and

a seal positioned within the channel.

10. The rotary vane air motor locking assembly of claim 1 and further comprising:

a bearing cap disposed between the annular stator housing and the second end cap, the bearing cap comprising:

a disk-shaped body;

a rotor bore extending through the disk-shaped body to receive the stub shaft of the rotor; and

a bearing pocket comprising a counterbore surrounding the rotor bore to face away from the rotor pocket.

11. The rotary vane air motor locking assembly of claim 10 wherein:

the second end plate comprises an annular flange extending from the second end plate to engage the annular stator housing; and

the annular stator housing further comprises a shoulder disposed at the second axial end to receive the bearing cap, wherein the second end plate is spaced from the second axial end of the annular stator housing by the bearing cap.

12. The rotary vane air motor locking assembly of claim 1 wherein the first end plate comprises:

a rotor bore for receiving the drive shaft of the rotor;

a bearing pocket comprising a counterbore surrounding the rotor bore to face away from the rotor pocket;

a mounting surface extending perpendicular to the axis of rotation; and a channel for receiving a seal surrounding the bearing pocket.

13. The rotary vane air motor locking assembly of claim 1 and further comprising:

a first bearing positioned adjacent the first end plate to support the drive shaft; and

a second bearing positioned adjacent the second end plate to support the stub shaft;

wherein the rotor is freely rotatable on the first and second bearings when the locking mechanism is disengaged.

14. The rotary vane air motor locking assembly of claim 1 wherein:

the locking assembly is fluidly coupled to the rotor pocket such that pressurized air provided to the rotor pocket inhibits engagement with the rotor vane assembly.

15. A rotary vane air motor comprising:

a rotor vane assembly comprising:

a rotor having an axis of rotation;

a plurality of slots disposed within the rotor;

a plurality of vanes disposed within the plurality of slots; and an anti-rotation socket extending into the rotor;

a stator housing surrounding the rotor vane assembly and comprising:

an annular body forming a rotor pocket eccentric with the axis of rotation; and

an end wall comprising:

a plate disposed alongside the annular body; and

a locking pocket extending from the plate; and

a locking mechanism disposed within the locking pocket, the locking mechanism comprising: a stud disposed within the locking pocket and aligned with the anti- rotation socket; and

a spring configured to bias the stud into the locking pocket and away from the socket;

wherein the stud is displaceable within the locking pocket to overcome force of the spring and engage the anti-rotation socket.

16. The rotary vane air motor of claim 15 and further comprising:

a stub shaft extending from an end of the rotor along the axis of rotation, the stub shaft including the anti-rotation socket;

a rotor bore extending through the plate to receive the stub shaft; a pocket wall surrounding the rotor bore to form the locking pocket; and a retention flange extending radially from the pocket wall to overhang the locking pocket and retain the stud within the locking pocket.

17. The rotary vane air motor of claim 16 wherein the locking mechanism further comprises:

a knob accessible from an exterior of the locking pocket, the stud extending axially from the knob;

a flange extending from the knob to engage the retention flange; a channel disposed within the flange; and

a seal positioned within the channel.

18. The rotary vane air motor locking assembly of claim 15 and further comprising:

a bearing cap disposed between the annular body and the end wall, the bearing cap comprising:

a disk-shaped body;

a rotor bore extending through the disk-shaped body to receive the stub shaft of the rotor; and

a bearing pocket comprising a counterbore surrounding the rotor bore to face away from the rotor pocket;

an annular flange extending from the end wall to engage the annular body; and

a shoulder disposed at an end of the annular body to receive the bearing cap, wherein the end wall is spaced from the end of the annular body by the bearing cap.

19. The rotary vane air motor locking assembly of claim 15 wherein the rotor pocket is in fluid communication with the locking pocket such that pressurized air supplied to the locking pocket from the rotor pocket inhibits displacement of the stud.

20. An anti-rotation locking mechanism for a rotary vane air motor having a rotor vane assembly disposed within a stator housing, the anti-rotation locking mechanism comprising:

an end plate for joining to the rotary vane air motor alongside the rotor vane assembly;

a bore passing through the end plate;

a locking pocket surrounding the bore;

a retention flange extending from the locking pocket toward the bore;

a stop comprising:

a knob extending from the locking pocket through the bore so as to be accessible outside the locking pocket;

a stop flange extending radially from the knob to engage the retention flange within the locking pocket; and

a shaft extending axially from the knob into the locking pocket; and a spring surrounding the shaft within the locking pocket.

21. The anti-rotation locking mechanism of claim 20 and further comprising:

a counterbore disposed within the end plate opposite the locking pocket; a washer surrounding the shaft within the counterbore such that the spring is disposed between the washer and the knob.

22. An anti-rotation locking mechanism of claim 21 and further comprising:

a channel disposed within the stop flange opening to the locking pocket; and a seal disposed within the channel.