US3920082A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Power tool with torque sensing control means
Assignee: Thor Power Tool Co
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Filing: 1973-05-14
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Granted: 1975-11-18
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Expires: 1993-05-14
Abstract
Abstract A pneumatic power tool having a torque sensing control system is disclosed which is capable of consistently applying a precise torque to a fastener so that uniform tightening of any number of fasteners can be obtained. A torsional strain responsive transducer is mounted internally in the tool body and includes a strain gauge network mounted on a torsionally resilient portion of one of the gear cases of the drive train of the tool, the gear case being subject to a reaction component of the torque being transmitted through the drive train. The strain gauge network provides a control signal which effects energization of a solenoid-actuated air shut-off valve in the handle of the tool to automatically terminate the operation of the tool when a predetermined torque is obtained at the output spindle. The control system permits adjustment of the torque output of the tool and provides a visual readout of such output. Because of its fast action, the solenoid-actuated shut-off valve substantially eliminates reaction torque at the handle of the tool and the components thereof are compactly arranged. The sound level of the exhaust air from the pneumatic motor is attenuated by a tortuous flow path through the interior of the tool, and the electrical conductors for the strain gauge network are also routed through the interior of the tool. Consequently, the exterior of the tool is clean. The portion of the housing of the tool that surrounds the transducer is in two parts so that certain of the components of the tool may be assembled without relative rotational movement. The two-piece housing also facilitates access to the transducer and other parts of the tool without disassembling the same.
Inventors
- 👤 Edmund C Dudek
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 07:48
CPC Classifications
B; B25; B25B; B25B21/00; B25B23/00; B25B23/14; B25B23/145; B25B23/1456
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
175 words
In a power tool including torque output means and a tool body having a motor therein and drive means connecting said motor with said torque output means, the improvement of torque sensing control means for automatically shutting off said motor when the torque output of said torque output means reaches a predetermined value, said control means including transducer means in said tool body and subjected to a reaction torque from a substnatially stationary member of said drive means, said transducer means including an axially extending sleeve having one end fixed in said body, ring gear means carried at the other end of the sleeve, sensing means on said sleeve and spaced axially of said ring gear means for sensing torsional load on said ring gear means, said drive means including reduction gearing including said ring gear means, said reduction gearing being unsupported by said tranducer means, said transducer means providing a control signal proportional to the torque output of said torque output means, and means responsive to said control signal for shutting off said motor.
Claim 2
Dependent Claim
175 words
In a power tool including torque output means and a tool body having a motor therein and drive means connecting said motor with said torque output means, the improvement of torque sensing control means for automatically shutting off said motor when the torque output of said torque output means reaches a predetermined value, said control means including transducer means in said tool body and subjected to a reaction torque from a substnatially stationary member of said drive means, said transducer means including an axially extending sleeve having one end fixed in said body, ring gear means carried at the other end of the sleeve, sensing means on said sleeve and spaced axially of said ring gear means for sensing torsional load on said ring gear means, said drive means including reduction gearing including said ring gear means, said reduction gearing being unsupported by said tranducer means, said transducer means providing a control signal proportional to the torque output of said torque output means, and means responsive to said control signal for shutting off said motor.
Claim 3
Dependent Claim
95 words
The power tool of claim 1, further characterized in that said control means includes a visual torque readout device, said motor has a rotor connected to said drive means, and locking means is provided for releasably locking said rotor against rotation to permit the application of a known torque load to said torque output means and adjustment of said torque readout device, said locking means comprising an opening in said tool body and communicating with the interior of said motor, said opening being adapted to receive a pin or the like for engaging said rotor.
Claim 4
Dependent Claim
17 words
The power tool of claim 1, further characterized in that said sensing means comprises an electromechanical transducer.
Claim 5
Dependent Claim
41 words
The power tool of claim 3, further characterized in that said drive means comprises at least one planetary reduction gear train having at least one idler gear, said ring rear means meshing with said idler gear included in said reduction gearing.
Claim 6
Dependent Claim
33 words
The power tool of claim 4, further characterized in that said planetary reduction gear train includes two stages, and said transducer means is operatively associated with the ring gear of said second stage.
Claim 7
Dependent Claim
256 words
In a power tool including torque output means, a fluid motor, a housing, drive means connecting said fluid motor with said torQue output means, and passage means for supplying fluid motor, the improvement comprising torque sensing control means for sensing the torque output of said torque output means and automatically shutting off the flow of motive fluid to said fluid motor when the torque output of said torque output means reaches a predetermined value, said control means including transducer means, said transducer means including an axially extending sleeve having one end fixed in said housing, ring gear means carried at the other end of the sleeve, sensing means on said sleeve spaced axially of said ring gear means for sensing torsional load on said ring gear means, said drive means including reduction glaring including said ring gear means, said reduction gearing being unsupported by said transducer means, and means responsive to a predetermined control signal from said transducer means for controlling the operation of said fluid motor, said last mentioned means including a shut-off valve assembly comprising a shut-off valve member and a solenoid-actuated pilot valve member, said shut-off valve member being mounted in said fluid supply passage means and movable between a first position permitting fluid flow through said supply passage means and a second position preventing fluid flow through said supply passage means, and said solenoid-actuated pilot valve member being operable to effect movement of said shut-off valve member of said second position in response to said predetermined control signal from said transducer means.
Claim 8
Dependent Claim
256 words
In a power tool including torque output means, a fluid motor, a housing, drive means connecting said fluid motor with said torQue output means, and passage means for supplying fluid motor, the improvement comprising torque sensing control means for sensing the torque output of said torque output means and automatically shutting off the flow of motive fluid to said fluid motor when the torque output of said torque output means reaches a predetermined value, said control means including transducer means, said transducer means including an axially extending sleeve having one end fixed in said housing, ring gear means carried at the other end of the sleeve, sensing means on said sleeve spaced axially of said ring gear means for sensing torsional load on said ring gear means, said drive means including reduction glaring including said ring gear means, said reduction gearing being unsupported by said transducer means, and means responsive to a predetermined control signal from said transducer means for controlling the operation of said fluid motor, said last mentioned means including a shut-off valve assembly comprising a shut-off valve member and a solenoid-actuated pilot valve member, said shut-off valve member being mounted in said fluid supply passage means and movable between a first position permitting fluid flow through said supply passage means and a second position preventing fluid flow through said supply passage means, and said solenoid-actuated pilot valve member being operable to effect movement of said shut-off valve member of said second position in response to said predetermined control signal from said transducer means.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-11-17 | 1979-05-19 | 1979-11-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-17 | 1983-05-19 | 1983-11-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-17 | 1987-05-19 | 1987-11-18 | $7700.00 | Window Closed / Lapsed |