US3775911A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dual safety control for a power tool
Assignee: Thor Power Tool Co
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Filing: 1972-01-24
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Granted: 1973-12-04
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Expires: 1992-01-24
Abstract
Abstract A safety control for a portable power tool such as a pneumatically driven hand grinder. A pair of throttles are secured to the tool housing for guiding and controlling the operation of the tool when the latter is in use. A valve is mounted in each throttle and both valves are normally biased to their closed positions by springs. An operating lever is pivotally mounted on each throttle for moving its associated valve to an open position. The valves are arranged in series in a pair of connected passages which convey air under pressure from a remote source to the pneumatic drive motor of the tool. The tool is therefore rendered inoperative whenever one or the other or both of the throttle levers is intentionally or inadvertently released.
Inventors
- 👤 A Flagge
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 21:12
CPC Classifications
B; B24; B24B; B24B23/00; B24B23/02; B24B23/026
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
198 words
In a portable power tool including a housing having a fluid motor therein and a driven member connected to said motor and adapted to have a work performing member connected thereto, the improvement of safety control means for controlling the operation of said motor said safety control means comprising first and second throttles adapted to be secured to said housing and respectively adapted to be grasped by a user''s hands, first and second control members respectively carried by said first and second throttles, said control members being operable to prevent motive fluid under pressure from being supplied to said motor when either of said control members is in a first position and to permit motive fluid under pressure to be supplied to said motor only when both of said control members are in a second position, means normally biasing said control members to said first position, and manually actuated means carried by each of said throttles for moving said first and second control members to said second position, whereby said safety control means will render said tool inoperative to drive said driven member whenever a user releases one or the other or both of said manually actuated means.
Claim 2
Dependent Claim
198 words
In a portable power tool including a housing having a fluid motor therein and a driven member connected to said motor and adapted to have a work performing member connected thereto, the improvement of safety control means for controlling the operation of said motor said safety control means comprising first and second throttles adapted to be secured to said housing and respectively adapted to be grasped by a user''s hands, first and second control members respectively carried by said first and second throttles, said control members being operable to prevent motive fluid under pressure from being supplied to said motor when either of said control members is in a first position and to permit motive fluid under pressure to be supplied to said motor only when both of said control members are in a second position, means normally biasing said control members to said first position, and manually actuated means carried by each of said throttles for moving said first and second control members to said second position, whereby said safety control means will render said tool inoperative to drive said driven member whenever a user releases one or the other or both of said manually actuated means.
Claim 3
Dependent Claim
83 words
The safety control means of claim 1, further characterized in that said motor has a shaft, said first and second throttles respectively include first and second handle means adapted to lie in a plane generally perpendicular to the axis of said of said motor shaft and to be disposed in spaced, angularly extending relation, and said manually actuated means comprises a pair of pivotally mounted levers on said first and second handle means and having their pivot axes disposed adjacent to said housing.
Claim 4
Dependent Claim
52 words
The safety control means of claim 2, further characterized in that said motor has an inlet and an outlet, fluid conduit means is provided for conducting fluid under pressure to said inlet, and said control members comprise a pair of valves adapted to be arranged in series in said fluid conduit means.
Claim 5
Dependent Claim
189 words
In a portable grinder or the like including a housing having a fluid motor therein and a wall having a fluid entrance port, said motor having a fluid inlet, a fluid outlet and an output shaft connected thereto, and a duct extending between said fluid entrance port and said fluid inlet, the improvement of dual control means for controlling the operation of said grinder, said control means comprising an adapter adapted to be secured to said wall of said housing and having at least a portion of a fluid conduit means therein for conducting fluid under pressure from a remote source thereof to said fluid entrance port, and first and second throttles secured to said adapter and respectively adapted to be grasped by a user''s hands, said throttles having manually actuated valves therein cooperable in series flow relation with said portion of said fluid conduit means means so as to prevent fluid under pressure from being supplied to said fluid motor when either of said valves is closed and to permit fluid under pressure to be supplied to said fluid motor only when both of said valves are open.
Claim 6
Dependent Claim
189 words
In a portable grinder or the like including a housing having a fluid motor therein and a wall having a fluid entrance port, said motor having a fluid inlet, a fluid outlet and an output shaft connected thereto, and a duct extending between said fluid entrance port and said fluid inlet, the improvement of dual control means for controlling the operation of said grinder, said control means comprising an adapter adapted to be secured to said wall of said housing and having at least a portion of a fluid conduit means therein for conducting fluid under pressure from a remote source thereof to said fluid entrance port, and first and second throttles secured to said adapter and respectively adapted to be grasped by a user''s hands, said throttles having manually actuated valves therein cooperable in series flow relation with said portion of said fluid conduit means means so as to prevent fluid under pressure from being supplied to said fluid motor when either of said valves is closed and to permit fluid under pressure to be supplied to said fluid motor only when both of said valves are open.
Claim 7
Dependent Claim
45 words
The dual control means of claim 4, further characterized in that said first and second throttles respectively include first and second handle means secured to said adapter in spaced relation, and said manually actuated valves are respectively mounted in said first and second handle means.
Claim 8
Dependent Claim
93 words
The dual control means of claim 5, further characterized in that said portion of said fluid conduit means comprises a pair of elongated passages having opposite ends, said valve in said first handle means communicates with on end of one of said passages, said valve in said second handle means is positioned in a cavity therein, said cavity communicates with the other end of sAid one passage and with one end of said other passage, and the the other end of said other passage is adapted to communicate with said fluid entrance port.
Claim 9
Dependent Claim
34 words
The dual control means of claim 6, further characterized in that said passages in said adapter are generally parallel to each other and the flow of fluid through said passages is in opposite directions.
Claim 10
Dependent Claim
79 words
The dual control means of claim 6, further characterized in that at least said first handle means has an elongated hollow interior, one end of said hollow interior is adapted to be connected to said source of fluid under pressure, and the other end of said hollow interior is connected to said cavity, whereby the hollow interior of said first handle means initially receives fluid under pressure from said source and comprises another portion of said fluid conduit means.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-12-03 | 1977-06-04 | 1977-12-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-03 | 1981-06-04 | 1981-12-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-03 | 1985-06-04 | 1985-12-04 | $7700.00 | Window Closed / Lapsed |