CA1125593A - Speed responsive motor shutoff mechanism for fluid operated tool - Google Patents
Speed responsive motor shutoff mechanism for fluid operated toolInfo
- Publication number
- CA1125593A CA1125593A CA337,500A CA337500A CA1125593A CA 1125593 A CA1125593 A CA 1125593A CA 337500 A CA337500 A CA 337500A CA 1125593 A CA1125593 A CA 1125593A
- Authority
- CA
- Canada
- Prior art keywords
- motor
- closure member
- set forth
- fluid
- invention set
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25B—TOOLS OR BENCH DEVICES NOT OTHERWISE PROVIDED FOR, FOR FASTENING, CONNECTING, DISENGAGING OR HOLDING
- B25B23/00—Details of, or accessories for, spanners, wrenches, screwdrivers
- B25B23/14—Arrangement of torque limiters or torque indicators in wrenches or screwdrivers
- B25B23/145—Arrangement of torque limiters or torque indicators in wrenches or screwdrivers specially adapted for fluid operated wrenches or screwdrivers
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Details Of Spanners, Wrenches, And Screw Drivers And Accessories (AREA)
- Electrically Driven Valve-Operating Means (AREA)
- Hydraulic Motors (AREA)
- Control Of Throttle Valves Provided In The Intake System Or In The Exhaust System (AREA)
- Fluid-Pressure Circuits (AREA)
- Lift Valve (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A portable pneumatic tool includes a valve closure member interposed in the tool motor exhaust passage and engaged with a speed responsive mechanism comprising a plurality of flyweights operable to move the closure member to an open position on starting of the tool motor. On decreasing motor speed a coil spring assisted by a fluid pressure drop across the closure member forces the closure member to move against the decreasing centri-fugal force exerted by the flyweights to shut off-motor exhaust fluid flow to stop the motor. The closure member is normally held in a partially open position by a second spring to enable the motor to be started.
A portable pneumatic tool includes a valve closure member interposed in the tool motor exhaust passage and engaged with a speed responsive mechanism comprising a plurality of flyweights operable to move the closure member to an open position on starting of the tool motor. On decreasing motor speed a coil spring assisted by a fluid pressure drop across the closure member forces the closure member to move against the decreasing centri-fugal force exerted by the flyweights to shut off-motor exhaust fluid flow to stop the motor. The closure member is normally held in a partially open position by a second spring to enable the motor to be started.
Description
SPEED RESPONSIVE MOTOR SHUTOFF MECHANISM
FOR FLUID OPERAI'ED TOOL
BACKGROUND OF THE INVENTION
This invention pertains to a speed responsive shutoff mechanism for a pneumatic nut running-tool wherein the motor exhaust flow is interrupted at a predetermined minimum speed of the tool motor as the motor approaches the stall condition.
In the art of control devices for pneumatic power tools, in particular nutsetters, screwdrivers and the like, there have been a number of inventions dealing with a speed responsive valve for shutting off the motor inlet air flow when the motor speed approaches the stall condition. U.S. Patents 3,904,305; 4,004,859 10 and 4,120,604 disclose pneumatic tools which include speed res-ponsive valve mechanisms for shutting off fluid flow to the motor inlet port when the motor approaches the stall condition from a relatively high speed operating condition. U.S. Patents 3,785,442;
3,791,458 and 3,850,553 disclose speed responsive devices which generate a pressure fluid signal at a predetermined minimum speed of the tool motor to cause a servo-operated valve to shut off motive fluid flow.
A common disadvantage of the devices disclosed in the first three patents abovementioned is that although the speed responsive devices operate to shut off direbtly the fluid flow to the motor inlet port, these devices all require a so-called bypass valve for providing motive air to start the motor so that the respective centrifugal force responsive mechanisms can open a motor inlet fluid passage which is then reclosed on decreasing motor speed.
The three last mentioned patents also disclose somewhat com-plicated mechanisms which require speed responsive valve devices that provide a pressure fluid signal for operating separate motive fluid shutoff valves.
112~;i5~3 SUMMARY OF THE INVENTION
The present invention provides for a speed responsive motive fluid shutoff device for a fluid operated tool such as a pneumatic nutsetter or the like which operates to shut off the motive fluid exhaust flow from the tool motor in response to decreasing motor speed. Accordingly, the shutoff -device according to the present invention may be used to control the maximum torque exerted by the tool on a driven fastener. The motor shutoff mechanism of the present invention also functions to indicate that the tool motor speed has decreased to a predetermined minimum on approach-ing a stalled condition. Moreover, the motor shutoff mechanismin accordance with the present invention is designed to minimize ., the torque reaction imposed on the tool operator as the tool motor approaches the stalled high output torque condition.
~The speed responsive motor exhaust flow shutoff valve is particularly advantageous in that a disc or plate type valve closure member is arranged in the motor exhaust fluid flow path and is actuated substantially directly by a speed responsive flyweight mechanism. Moreover, the motor exhaust flow shutoff valve does not require a bypass valve for providing motive fluid to start the tool motor as with prior art mechanisms.
Accordingly, the speed responsive motor shutoff mechanism of the present invention is compact, mechanically simple, less complicated, and less expensive than heretofore known speed res-ponsive motor shutoff devices for fluid operated tools.
BRIEF DESCRIPTION OF THE DRAWING
Fig. 1 is a longitudinal side elevation of a portable pneu-matic tool which includes the speed responsive motor shutoff mechanism of the present invention;
Fig. 2 is a longitudinal center section of the speed respon-sive motor shutoff mechanism embodied in the tool shown in Fig. l;
and, 1~4'~S~
Fig. 3 is a section view taken along the line 3-3 of Fig. 2.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to Fig. 1 of the drawing the speed responsive motor shutoff mechan-ism of the present invention is adapted,to be used in a portable pneumatic tool gene~ally designated by the numeral 10 and comprising a nutsetter. The tool 10 includes a housing portion 12 in which is disposed a conventional rotary vane type expansible chamber motor 14. Motive fluid such as compressed air is supplied to the tool by way of a flexible conduit 16 connected to the tool handle 18. A manually actuated shutoff valve 20,shown schematically in Fig. 1, is operable to control the supply of pressure fluid to the motor by way of passage 22. The valve 20 is shown schematically in Fig. 1 for clarity and is adapted to be disposed in the tool housing and to be actuated by a suitable operating lever 24. The tool 10 also includes a housing portion 26 which includes a drive shaft 28 suitably connected to a socket member 30 for driving a threaded fastener or the like in a known way.
The tool 10 further includes a housing portion 32 intermediate the housing portions 12 and 26 and suitably secured thereto by respective threaded collars 34 and 36. Referring to Fig. 2, the housing portion 32 is adapted to have interior chambers 38 and 40 which may be in fluid conducting communication with each other to form passage means for the exhaust fluid flow from the motor 14. Exhaust fluid from the motor 14 is conducted to the chamber 38 through motor exhaust port means 42 in the motor end plate 44.
Exhaust fluid flows from the chamber 40 through the hollow interior of the housing portion 26 and exits from the tool through suitable louvers 46, shown in Fig. 1.
Referring again to Fig. 2, the motor 14 includes a rotor 48 having an output shaft portion 50 which is drivably coupled to S5~
an intermediate drive shaft 52. The drive shaft 52 is rotatablY
supported in the housing portion 32 and includes a portion forming the sun gear 54 of a planetary gear drive. The planetary gear drive includes a planet gear carrier 56 which is drivably connected to the final drive shaft 28. The speed responsive motor shutoff mechanism of the present invention 1ncludes a member 58 disposed on the drive shaft 52 for rotation therewith. The member 58 includes a plurality of generally radially extending grooves 60 formed therein, see Fig. 3 also. The grooves 60 are formed to have inclined bottom surfaces 62 and the grooves each contain a movable flyweight or spherical ball 64 which is movable along the groove radially outwardly with respect to the drive shaft . ., 52 in response to centrifugal force. The speed responsive motor shutoff mechanism further includes an axially movable member 66 forming a valve closure member for interrupting the flow of exhaust fluid from the chamber 38 to the chamber 40. The closure member 66 is axially slidably supported by a hub portion 68 of the motor end plate 44 and by the intermediate drive shaft 52.
The closure member 66 is operable to engage a seat 70 formed by a transverse wall surface facing the interior chamber 38. The closure member 66 is biased toward the seat 70 by a coil spring 72 disposed between a flange 74 on the closure member and the motor end plate 44.
The closure member 66 includes a recess 76 opening to one end thereof in which the member 58 is partially disposed. An annular plate 78 is also disposed in the recess 76 and is engage-able with the balls 64 even when they are disposed in their radially innermost positions in the grooves 60. A circular disc spring washer 80 is disposed between the plate 78 and the bottom of the recess 76. The stiffness of the spring washer 80 is greater than the stiffness of the spring 72 and the spring washer exerts a biasing force in opposition to the spring 72. Accordingly, when SC~3 the fluid pressure in the chambers 38 and 40 is essentially the same the spring washer 80 holds the closure member 66 a short distance away from the seat 70 as shown in Fig. 2.
Accordingly, when pressure fluid is introduced to the motor 14 on startuE somcexhaust fluid flow is allowed to pass through the chambers 38 and 40 to enable the motor to start. Once the motor 14 has commenced to rotate the shaft 52 rapidly, the balls 64 are forced radially outwardly in the grooves 60 and due to the inclined bottom surfaces 62 the balls force the plate 78 and the closure member 6,6 to the right, viewing Fig. 2, to increase the size of the passageway formed between the closure member and the seat 70. Therefore, when the motor 14 is operating at greater ., than idle speed or greater than approximately ten percent of its free speed, the exhaust flow is not impeded.
lS In normal operation of the tool 10 for running down and tightening a threaded fastener, when the motor 14 is at rest and the valve 20 is closed, the closure member 66 is in the position shown in Fig. 2. When the valve 20 is moved to the position to conduct pressure fluid through the passage 22 to the motor 14 the initial flow of motive fluid permitted by the small opening between the closure member 66 and the seat 70 is sufficient to allow the motor to accelerate enough to cause the balls 64 to force the closure member to the fully open position. The closure member 66 will remain in a substantially full open position with the spring 72 compressed until rotative speed of the motor 14 and the drive shaft 52 decreases to approximately ten percent of the motor free or unloaded speed. This reduced speed is normally commensurate with the desired maximum torque to be delivered by the motor to .~
the fastener being tightened. As the motor speed decreases to the condition mentioned above, the bias of the spring 72 will force the balls 64 radially inward in the grooves 60 overcoming the reduced centrifugal forces acting on the balls and the closure _5_ ~ ~5tj~ ~
member will move toward the,seat 70. As the passageway formed between the closure member 66 and the seat becomes more restricted with movement of the closure member, the exhaust fluid pressure in the chamber 38 increases in relation to the pressure in chamber 40 and a pressure force acting on the flange 74 will cause the , .
closure member to move rapidly in^to engagement with the seat overcoming the bias force of the spring washer 80. When the exhaust flow is shut off entirely the motor 14 will stop and the fluid pressure difference across the motor will quickly diminish to reduce substantially the motor output torque whether or not the valve 20 remains open or closed.
When the valve 20 is released by the tool operator the fluid pressure in the motor 14 as well as the exhaust chamber 38 will be reduced due to leakage flow and venting through the valve 20 in the closed position. When the fluid pressure in the chamber 38 decreases sufficiently, the spring washer 80 will move the closure member 66 away from the seat 70 to the position shown in Fig. 2 and the shutoff mechanism will be ready for another operating cycle of the tool 10.
What is claimed is:
. . .
. _ _ . _ _ .. . . . .. . . . _ . _ 55~.f3 SUPPLEMENTARY DISCLOSURE
An alternate embodiment of the present invention is shown in Figures 4 and 5. Referring to Figure 4 the motor rotor output shaft portion 50 is drivably connected to a coupling member 82 having cylindrical journal 83 5 and a plural;ty of spiral grooves 84 formed on the periphery thereof, as shown also in Figure 5. The coupling member 82 is drivably connected to the shaft 52. A closure member 86 similar to the closure member 66 is mounted on the coupling member 82 and includes a hub portion 88 having spaced apart holes 90 in which are disposed ball keys 92. The ball keys c 10 92 extend into the grooves 84 to form a driving connection between the coupling member 82 and the closure member. The ball keys 92 are retained in engagement with the closure member 86 and the coupling member 82 by a spring band 94. Accordingly, the closure member 86 is operable to move axially on the coupling member 82 between a shoulder 96 on the coupling 15 member and a retaining ring 98 also disposed on the coupling member. In moving axially the closure member 86 also undergoes some rotation with respect to the coupling member because of the coupling formed by the ball keys 92 and the spiral grooves 84.
The shutoff mechanism sh~n in Figures 4 and 5 operates in a manner 20 similar to the mechanism shown in Figures 1 through 3, that is, when the motor 14 is at rest and the valve 20 is closed the closuré member 86 nor-mally assumes the position shown in Figure 4. However, because of the limited motion coupling formed between the member 82, and the closure member 86 the closure member may be in a further open position. Accord-25 ingly, when the valve 20 ;s opened the motor 14 will accelerate the balls 64 to force the closure member 86 to the fully open position if in fact it is not already in that position. The coupling formed between the closure member 86 and the coupling member 82 will also assist in moving the closure member toward the open position due to the inertia of the closure member.
When motor speed decreases due to increased torque and the balls 64 move radially inwardly in the grooves 60 the angular momentum of the ro-.~
1~5SC~3 tating closure member 86 will urge it to move with respect to the coupling member 82 rotatably and axially toward the valve seat 70. As the closure member 86 approaches the seat 70 the reduced flow area formed between the seat and the closure member will create a pressure differential acting on the flange 99 of the closure member causing the same tg move rapidly toward the closed position whereby the motor 14 will stop. As in the embodiment of Figures 1 thru 3 the valve closure member 86 will remain closed as long as the valve 20 is held open and a pressure differential exists across the flange 99 of the closure member. When the pressure in the chamber 38 is reduced upon closure of the valve 20 the spring washer 80 will move the closure member 86 to the partially open position shown in Figure 4 so that another operating cycle may be commenced upon opening of the valve 20.
~1¢'~'' i ....' . ~
FOR FLUID OPERAI'ED TOOL
BACKGROUND OF THE INVENTION
This invention pertains to a speed responsive shutoff mechanism for a pneumatic nut running-tool wherein the motor exhaust flow is interrupted at a predetermined minimum speed of the tool motor as the motor approaches the stall condition.
In the art of control devices for pneumatic power tools, in particular nutsetters, screwdrivers and the like, there have been a number of inventions dealing with a speed responsive valve for shutting off the motor inlet air flow when the motor speed approaches the stall condition. U.S. Patents 3,904,305; 4,004,859 10 and 4,120,604 disclose pneumatic tools which include speed res-ponsive valve mechanisms for shutting off fluid flow to the motor inlet port when the motor approaches the stall condition from a relatively high speed operating condition. U.S. Patents 3,785,442;
3,791,458 and 3,850,553 disclose speed responsive devices which generate a pressure fluid signal at a predetermined minimum speed of the tool motor to cause a servo-operated valve to shut off motive fluid flow.
A common disadvantage of the devices disclosed in the first three patents abovementioned is that although the speed responsive devices operate to shut off direbtly the fluid flow to the motor inlet port, these devices all require a so-called bypass valve for providing motive air to start the motor so that the respective centrifugal force responsive mechanisms can open a motor inlet fluid passage which is then reclosed on decreasing motor speed.
The three last mentioned patents also disclose somewhat com-plicated mechanisms which require speed responsive valve devices that provide a pressure fluid signal for operating separate motive fluid shutoff valves.
112~;i5~3 SUMMARY OF THE INVENTION
The present invention provides for a speed responsive motive fluid shutoff device for a fluid operated tool such as a pneumatic nutsetter or the like which operates to shut off the motive fluid exhaust flow from the tool motor in response to decreasing motor speed. Accordingly, the shutoff -device according to the present invention may be used to control the maximum torque exerted by the tool on a driven fastener. The motor shutoff mechanism of the present invention also functions to indicate that the tool motor speed has decreased to a predetermined minimum on approach-ing a stalled condition. Moreover, the motor shutoff mechanismin accordance with the present invention is designed to minimize ., the torque reaction imposed on the tool operator as the tool motor approaches the stalled high output torque condition.
~The speed responsive motor exhaust flow shutoff valve is particularly advantageous in that a disc or plate type valve closure member is arranged in the motor exhaust fluid flow path and is actuated substantially directly by a speed responsive flyweight mechanism. Moreover, the motor exhaust flow shutoff valve does not require a bypass valve for providing motive fluid to start the tool motor as with prior art mechanisms.
Accordingly, the speed responsive motor shutoff mechanism of the present invention is compact, mechanically simple, less complicated, and less expensive than heretofore known speed res-ponsive motor shutoff devices for fluid operated tools.
BRIEF DESCRIPTION OF THE DRAWING
Fig. 1 is a longitudinal side elevation of a portable pneu-matic tool which includes the speed responsive motor shutoff mechanism of the present invention;
Fig. 2 is a longitudinal center section of the speed respon-sive motor shutoff mechanism embodied in the tool shown in Fig. l;
and, 1~4'~S~
Fig. 3 is a section view taken along the line 3-3 of Fig. 2.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to Fig. 1 of the drawing the speed responsive motor shutoff mechan-ism of the present invention is adapted,to be used in a portable pneumatic tool gene~ally designated by the numeral 10 and comprising a nutsetter. The tool 10 includes a housing portion 12 in which is disposed a conventional rotary vane type expansible chamber motor 14. Motive fluid such as compressed air is supplied to the tool by way of a flexible conduit 16 connected to the tool handle 18. A manually actuated shutoff valve 20,shown schematically in Fig. 1, is operable to control the supply of pressure fluid to the motor by way of passage 22. The valve 20 is shown schematically in Fig. 1 for clarity and is adapted to be disposed in the tool housing and to be actuated by a suitable operating lever 24. The tool 10 also includes a housing portion 26 which includes a drive shaft 28 suitably connected to a socket member 30 for driving a threaded fastener or the like in a known way.
The tool 10 further includes a housing portion 32 intermediate the housing portions 12 and 26 and suitably secured thereto by respective threaded collars 34 and 36. Referring to Fig. 2, the housing portion 32 is adapted to have interior chambers 38 and 40 which may be in fluid conducting communication with each other to form passage means for the exhaust fluid flow from the motor 14. Exhaust fluid from the motor 14 is conducted to the chamber 38 through motor exhaust port means 42 in the motor end plate 44.
Exhaust fluid flows from the chamber 40 through the hollow interior of the housing portion 26 and exits from the tool through suitable louvers 46, shown in Fig. 1.
Referring again to Fig. 2, the motor 14 includes a rotor 48 having an output shaft portion 50 which is drivably coupled to S5~
an intermediate drive shaft 52. The drive shaft 52 is rotatablY
supported in the housing portion 32 and includes a portion forming the sun gear 54 of a planetary gear drive. The planetary gear drive includes a planet gear carrier 56 which is drivably connected to the final drive shaft 28. The speed responsive motor shutoff mechanism of the present invention 1ncludes a member 58 disposed on the drive shaft 52 for rotation therewith. The member 58 includes a plurality of generally radially extending grooves 60 formed therein, see Fig. 3 also. The grooves 60 are formed to have inclined bottom surfaces 62 and the grooves each contain a movable flyweight or spherical ball 64 which is movable along the groove radially outwardly with respect to the drive shaft . ., 52 in response to centrifugal force. The speed responsive motor shutoff mechanism further includes an axially movable member 66 forming a valve closure member for interrupting the flow of exhaust fluid from the chamber 38 to the chamber 40. The closure member 66 is axially slidably supported by a hub portion 68 of the motor end plate 44 and by the intermediate drive shaft 52.
The closure member 66 is operable to engage a seat 70 formed by a transverse wall surface facing the interior chamber 38. The closure member 66 is biased toward the seat 70 by a coil spring 72 disposed between a flange 74 on the closure member and the motor end plate 44.
The closure member 66 includes a recess 76 opening to one end thereof in which the member 58 is partially disposed. An annular plate 78 is also disposed in the recess 76 and is engage-able with the balls 64 even when they are disposed in their radially innermost positions in the grooves 60. A circular disc spring washer 80 is disposed between the plate 78 and the bottom of the recess 76. The stiffness of the spring washer 80 is greater than the stiffness of the spring 72 and the spring washer exerts a biasing force in opposition to the spring 72. Accordingly, when SC~3 the fluid pressure in the chambers 38 and 40 is essentially the same the spring washer 80 holds the closure member 66 a short distance away from the seat 70 as shown in Fig. 2.
Accordingly, when pressure fluid is introduced to the motor 14 on startuE somcexhaust fluid flow is allowed to pass through the chambers 38 and 40 to enable the motor to start. Once the motor 14 has commenced to rotate the shaft 52 rapidly, the balls 64 are forced radially outwardly in the grooves 60 and due to the inclined bottom surfaces 62 the balls force the plate 78 and the closure member 6,6 to the right, viewing Fig. 2, to increase the size of the passageway formed between the closure member and the seat 70. Therefore, when the motor 14 is operating at greater ., than idle speed or greater than approximately ten percent of its free speed, the exhaust flow is not impeded.
lS In normal operation of the tool 10 for running down and tightening a threaded fastener, when the motor 14 is at rest and the valve 20 is closed, the closure member 66 is in the position shown in Fig. 2. When the valve 20 is moved to the position to conduct pressure fluid through the passage 22 to the motor 14 the initial flow of motive fluid permitted by the small opening between the closure member 66 and the seat 70 is sufficient to allow the motor to accelerate enough to cause the balls 64 to force the closure member to the fully open position. The closure member 66 will remain in a substantially full open position with the spring 72 compressed until rotative speed of the motor 14 and the drive shaft 52 decreases to approximately ten percent of the motor free or unloaded speed. This reduced speed is normally commensurate with the desired maximum torque to be delivered by the motor to .~
the fastener being tightened. As the motor speed decreases to the condition mentioned above, the bias of the spring 72 will force the balls 64 radially inward in the grooves 60 overcoming the reduced centrifugal forces acting on the balls and the closure _5_ ~ ~5tj~ ~
member will move toward the,seat 70. As the passageway formed between the closure member 66 and the seat becomes more restricted with movement of the closure member, the exhaust fluid pressure in the chamber 38 increases in relation to the pressure in chamber 40 and a pressure force acting on the flange 74 will cause the , .
closure member to move rapidly in^to engagement with the seat overcoming the bias force of the spring washer 80. When the exhaust flow is shut off entirely the motor 14 will stop and the fluid pressure difference across the motor will quickly diminish to reduce substantially the motor output torque whether or not the valve 20 remains open or closed.
When the valve 20 is released by the tool operator the fluid pressure in the motor 14 as well as the exhaust chamber 38 will be reduced due to leakage flow and venting through the valve 20 in the closed position. When the fluid pressure in the chamber 38 decreases sufficiently, the spring washer 80 will move the closure member 66 away from the seat 70 to the position shown in Fig. 2 and the shutoff mechanism will be ready for another operating cycle of the tool 10.
What is claimed is:
. . .
. _ _ . _ _ .. . . . .. . . . _ . _ 55~.f3 SUPPLEMENTARY DISCLOSURE
An alternate embodiment of the present invention is shown in Figures 4 and 5. Referring to Figure 4 the motor rotor output shaft portion 50 is drivably connected to a coupling member 82 having cylindrical journal 83 5 and a plural;ty of spiral grooves 84 formed on the periphery thereof, as shown also in Figure 5. The coupling member 82 is drivably connected to the shaft 52. A closure member 86 similar to the closure member 66 is mounted on the coupling member 82 and includes a hub portion 88 having spaced apart holes 90 in which are disposed ball keys 92. The ball keys c 10 92 extend into the grooves 84 to form a driving connection between the coupling member 82 and the closure member. The ball keys 92 are retained in engagement with the closure member 86 and the coupling member 82 by a spring band 94. Accordingly, the closure member 86 is operable to move axially on the coupling member 82 between a shoulder 96 on the coupling 15 member and a retaining ring 98 also disposed on the coupling member. In moving axially the closure member 86 also undergoes some rotation with respect to the coupling member because of the coupling formed by the ball keys 92 and the spiral grooves 84.
The shutoff mechanism sh~n in Figures 4 and 5 operates in a manner 20 similar to the mechanism shown in Figures 1 through 3, that is, when the motor 14 is at rest and the valve 20 is closed the closuré member 86 nor-mally assumes the position shown in Figure 4. However, because of the limited motion coupling formed between the member 82, and the closure member 86 the closure member may be in a further open position. Accord-25 ingly, when the valve 20 ;s opened the motor 14 will accelerate the balls 64 to force the closure member 86 to the fully open position if in fact it is not already in that position. The coupling formed between the closure member 86 and the coupling member 82 will also assist in moving the closure member toward the open position due to the inertia of the closure member.
When motor speed decreases due to increased torque and the balls 64 move radially inwardly in the grooves 60 the angular momentum of the ro-.~
1~5SC~3 tating closure member 86 will urge it to move with respect to the coupling member 82 rotatably and axially toward the valve seat 70. As the closure member 86 approaches the seat 70 the reduced flow area formed between the seat and the closure member will create a pressure differential acting on the flange 99 of the closure member causing the same tg move rapidly toward the closed position whereby the motor 14 will stop. As in the embodiment of Figures 1 thru 3 the valve closure member 86 will remain closed as long as the valve 20 is held open and a pressure differential exists across the flange 99 of the closure member. When the pressure in the chamber 38 is reduced upon closure of the valve 20 the spring washer 80 will move the closure member 86 to the partially open position shown in Figure 4 so that another operating cycle may be commenced upon opening of the valve 20.
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Claims (17)
1. In a fluid operated tool for tightening threaded fasteners and the like:
a housing;
a fluid operated motor disposed in said housing;
means forming a fluid exhaust passage in said housing for conducting exhaust fluid away from said motor to the exterior of said housing;
a valve closure member operable to be in an open position to permit exhaust fluid flow through said exhaust passage and a closed position blocking the flow of exhaust fluid through said exhaust passage to stop said motor;
a member engaged with said motor and operable to be rotatably driven by said motor;
flyweight means engaged with said member and responsive to starting of said motor to move said closure member to a substantially full open position to permit the flow of exhaust fluid through said exhaust passage; and means responsive to decreasing motor speed to cause said closure member to move to said closed position.
a housing;
a fluid operated motor disposed in said housing;
means forming a fluid exhaust passage in said housing for conducting exhaust fluid away from said motor to the exterior of said housing;
a valve closure member operable to be in an open position to permit exhaust fluid flow through said exhaust passage and a closed position blocking the flow of exhaust fluid through said exhaust passage to stop said motor;
a member engaged with said motor and operable to be rotatably driven by said motor;
flyweight means engaged with said member and responsive to starting of said motor to move said closure member to a substantially full open position to permit the flow of exhaust fluid through said exhaust passage; and means responsive to decreasing motor speed to cause said closure member to move to said closed position.
2. The invention set forth in Claim 1 together with:
first spring means for biasing said closure member to move toward a closed position in response to a decreasing centri-fugal force on said flyweight means caused by the speed of said motor decreasing below a predetermined minimum.
first spring means for biasing said closure member to move toward a closed position in response to a decreasing centri-fugal force on said flyweight means caused by the speed of said motor decreasing below a predetermined minimum.
3. The invention set forth in Claim 2 together with:
second spring means for biasing said closure member to a partially open position to permit an initial flow of exhaust fluid from said motor upon starting said motor.
second spring means for biasing said closure member to a partially open position to permit an initial flow of exhaust fluid from said motor upon starting said motor.
4. The invention set forth in Claim 3 together with:
a motive fluid shutoff valve interposed in a motive fluid supply passage leading to said motor, said motive fluid shutoff valve being operable in its motive fluid shutoff position to vent pressure fluid from said motor and said exhaust passage between said motor and said closure member.
a motive fluid shutoff valve interposed in a motive fluid supply passage leading to said motor, said motive fluid shutoff valve being operable in its motive fluid shutoff position to vent pressure fluid from said motor and said exhaust passage between said motor and said closure member.
5. The invention set forth in Claim 3 wherein:
said member drivably engaged with said motor includes a plurality of substantially radially extending grooves, said grooves having respective inclined bottom surfaces, and said flyweight means comprises a plurality of spherical balls disposed one in each of said respective grooves and operable in response to centrifugal forces acting thereon to move radially outwardly in said grooves to cause said closure member to move to a fully open position.
said member drivably engaged with said motor includes a plurality of substantially radially extending grooves, said grooves having respective inclined bottom surfaces, and said flyweight means comprises a plurality of spherical balls disposed one in each of said respective grooves and operable in response to centrifugal forces acting thereon to move radially outwardly in said grooves to cause said closure member to move to a fully open position.
6. The invention set forth in Claim 5 wherein:
said means responsive to decreasing motor speed includes a plate interposed between said closure member and said balls and engageable with said balls, and said second spring means includes a spring washer interposed between and engaged with said plate and said closure member.
said means responsive to decreasing motor speed includes a plate interposed between said closure member and said balls and engageable with said balls, and said second spring means includes a spring washer interposed between and engaged with said plate and said closure member.
7. The invention set forth in Claim 2 wherein:
said housing includes first and second interior chambers forming at least part of said exhaust passage, a transverse wall surface in said first chamber forming a valve seat en-gageable by said closure member for shutting off the flow of exhaust fluid from said first chamber to said second chamber.
said housing includes first and second interior chambers forming at least part of said exhaust passage, a transverse wall surface in said first chamber forming a valve seat en-gageable by said closure member for shutting off the flow of exhaust fluid from said first chamber to said second chamber.
8. The invention set forth in Claim 7 wherein:
said closure member includes a pressure surface responsive to an increase in the exhaust fluid pressure in said first chamber when said closure member moves toward the valve closed position to assist said first spring means in biasing said closure member to engagement with said valve seat.
CLAIMS SUPPORTED BY THE SUPPLEMENTARY
DISCLOSURE
said closure member includes a pressure surface responsive to an increase in the exhaust fluid pressure in said first chamber when said closure member moves toward the valve closed position to assist said first spring means in biasing said closure member to engagement with said valve seat.
CLAIMS SUPPORTED BY THE SUPPLEMENTARY
DISCLOSURE
9. The invention set forth in Claim 1 together with:
a limited motion coupling drivably interconnecting said motor and said closure member and operable to urge said closure member to move toward a closed position in response to a decreasing centrifugal force on said flyweight means caused by the speed of said motor decreasing below a predetermined minimum.
a limited motion coupling drivably interconnecting said motor and said closure member and operable to urge said closure member to move toward a closed position in response to a decreasing centrifugal force on said flyweight means caused by the speed of said motor decreasing below a predetermined minimum.
10. The invention set forth in Claim 9 wherein:
said coupling includes a coupling member drivably connected to said motor and to said closure member and opera-ble in response to increasing motor speed to permit said fly-weights to move said closure member to said open position.
said coupling includes a coupling member drivably connected to said motor and to said closure member and opera-ble in response to increasing motor speed to permit said fly-weights to move said closure member to said open position.
11. The invention set forth in Claim 10 wherein:
said coupling member includes a journal portion, said closure member is disposed on said journal portion and said coupling includes means forming a driving connection between said coupling member and said closure member which provides for limited axial and rotational movement of said closure member with respect to said coupling member.
said coupling member includes a journal portion, said closure member is disposed on said journal portion and said coupling includes means forming a driving connection between said coupling member and said closure member which provides for limited axial and rotational movement of said closure member with respect to said coupling member.
12. The invention set forth in Claim 11 wherein:
said means includes spiral groove means on one of said members and key means engaged with the other of said members and extending into said groove means.
said means includes spiral groove means on one of said members and key means engaged with the other of said members and extending into said groove means.
13. The invention set forth in Claim 12 together with:
spring means for biasing said closure member to a partially open position to permit an initial flow of exhaust fluid from said motor upon starting said motor.
spring means for biasing said closure member to a partially open position to permit an initial flow of exhaust fluid from said motor upon starting said motor.
14. The invention set forth in Claim 13 together with:
a motive fluid shutoff valve interposed in a motive fluid supply passage leading to said motor, said motive fluid shutoff valve being operable in its motive fluid shutoff posi-tion to vent pressure fluid from said motor and said exhaust passage between said motor and said closure member.
a motive fluid shutoff valve interposed in a motive fluid supply passage leading to said motor, said motive fluid shutoff valve being operable in its motive fluid shutoff posi-tion to vent pressure fluid from said motor and said exhaust passage between said motor and said closure member.
15. The invention set forth in Claim 13 wherein:
said member drivably engaged with said motor includes a plurality of substantially radially extending grooves, said grooves having respective inclined bottom surfaces, and said flyweights comprise a plurality of spherical balls disposed one in each of said respective grooves and operable in response to centrifugal forces acting thereon to move radially outward in said grooves to cause said closure member to move to a fully open position.
said member drivably engaged with said motor includes a plurality of substantially radially extending grooves, said grooves having respective inclined bottom surfaces, and said flyweights comprise a plurality of spherical balls disposed one in each of said respective grooves and operable in response to centrifugal forces acting thereon to move radially outward in said grooves to cause said closure member to move to a fully open position.
16. The invention set forth in Claim 15 wherein:
said means responsive to decreasing motor speed includes a plate interposed between said closure member and said balls and engageable with said balls, and said spring means includes a spring washer interposed between and engaged with said plate and said closure member.
said means responsive to decreasing motor speed includes a plate interposed between said closure member and said balls and engageable with said balls, and said spring means includes a spring washer interposed between and engaged with said plate and said closure member.
17. The invention set forth in Claim 2 wherein:
said housing includes first and second interior chambers forming at least part of said exhaust passage, transverse wall surface in said first chamber forming a valve seat engageable by said closure member for shutting off the flow of exhaust fluid from said first chamber to said second chamber.
said housing includes first and second interior chambers forming at least part of said exhaust passage, transverse wall surface in said first chamber forming a valve seat engageable by said closure member for shutting off the flow of exhaust fluid from said first chamber to said second chamber.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US1348679A | 1979-02-21 | 1979-02-21 | |
| US013,486 | 1979-02-21 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1125593A true CA1125593A (en) | 1982-06-15 |
Family
ID=21760205
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA337,500A Expired CA1125593A (en) | 1979-02-21 | 1979-10-12 | Speed responsive motor shutoff mechanism for fluid operated tool |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPS5949874B2 (en) |
| CA (1) | CA1125593A (en) |
| DE (1) | DE3001731A1 (en) |
| FR (1) | FR2449920A1 (en) |
| GB (1) | GB2040766B (en) |
| SE (1) | SE441903B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112548552B (en) * | 2020-12-14 | 2024-07-12 | 深圳市海厚实业有限公司 | Full-automatic wire locking machine for motor |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3421414A (en) * | 1966-03-15 | 1969-01-14 | Ingersoll Rand Co | Flyweight |
| US3430521A (en) * | 1967-06-19 | 1969-03-04 | Ingersoll Rand Co | Power-operated tool having two-speed rotary output |
| US3520392A (en) * | 1968-05-16 | 1970-07-14 | Gardner Denver Co | Overload responsive clutch and motor exhaust valve |
| USRE27550E (en) * | 1971-01-14 | 1973-01-16 | Torque release and shut-off mechanism for pneumatic tools | |
| US3785442A (en) * | 1971-04-28 | 1974-01-15 | Chicago Pneumatic Tool Co | Pneumatic nut running tool with governor shut-off control |
| BE791093A (en) * | 1971-12-30 | 1973-03-01 | Gardner Denver Co | TOOL SPEED AUTOMATIC VARIATOR |
| US3791458A (en) * | 1972-10-30 | 1974-02-12 | Chicago Pneumatic Tool Co | Stall torque air shut-off control for pneumatic nut runners |
| US3850553A (en) * | 1973-10-15 | 1974-11-26 | Chicago Pneumatic Tool Co | Stall torque air shut-off control for pneumatic nut runners |
| US4004859A (en) * | 1975-08-18 | 1977-01-25 | Cooper Industries, Inc. | Air tool with speed responsive shutoff |
| US4019589A (en) * | 1975-12-02 | 1977-04-26 | Chicago Pneumatic Tool Company | Pulse motor nut runner |
-
1979
- 1979-10-12 CA CA337,500A patent/CA1125593A/en not_active Expired
- 1979-10-17 GB GB7936096A patent/GB2040766B/en not_active Expired
- 1979-11-21 SE SE7909628A patent/SE441903B/en unknown
- 1979-12-03 FR FR7929675A patent/FR2449920A1/en not_active Withdrawn
- 1979-12-28 JP JP54174009A patent/JPS5949874B2/en not_active Expired
-
1980
- 1980-01-18 DE DE19803001731 patent/DE3001731A1/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| JPS55112779A (en) | 1980-08-30 |
| GB2040766A (en) | 1980-09-03 |
| JPS5949874B2 (en) | 1984-12-05 |
| GB2040766B (en) | 1983-02-09 |
| DE3001731A1 (en) | 1980-08-28 |
| SE7909628L (en) | 1980-08-22 |
| SE441903B (en) | 1985-11-18 |
| FR2449920A1 (en) | 1980-09-19 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |