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US 4,057,113 AGranted
Pneumatically powered hand tool with speed-control governor
AssigneeRobert Bosch GmbH
InventorsKurt Paule, Karl Roll, Max Burklin
Life of this patent
Estimating the term…
Abstract
A pneumatic hand tool comprises a housing having a compressed-gas inlet and provided with a pneumatically powered motor which carries on one side a tool holder such as a chuck and on the other side a governor. A speed-control valve is operated by the governor and can close a first air passage between the inlet and the motor to maintain the motor speed below a predetermined limit. Another passage is provided which bypasses the governor-controlled speed-control valve and a valve is provided in this bypass conduit which is openable in order to allow the hand tool to operate at a speed substantially above the governor-established speed.
Claims10
A pneumatic hand tool comprising:
- a housing having a compressed-gas inlet;
- a pneumatically powered motor in said housing;
- a tool holder on said housing connected to said motor;
- a governor in said housing connected to said motor;
- a normally open speed-control valve in said housing closable by said governor only on said motor reaching a predetermined speed;
- means including one gas passage extending between said gas inlet and said governor for feeding compressed gas to said motor through said speed-control valve, whereby said motor is operated at or below said predetermined speed;
- means including another gas passage extending between said inlet and said motor around said speed-control valve and a bypass valve in said other passage displaceable between an open position for feeding compressed gas directly to said motor and thereby operating same at a speed greater than said predetermined speed and a closed position wherein said motor can operate no faster than said predetermined speed;
- and
- an operating member on said housing displaceable by the user of said tool and engageable with said bypass valve for displacing same into said open position.
6 more elements
A pneumatic hand tool comprising:
- a housing having a compressed-gas inlet;
- a pneumatically powered motor in said housing;
- a tool holder on said housing connected to said motor;
- a governor in said housing connected to said motor;
- a speed-control valve in said housing closable by said governor on said motor reaching a predetermined speed;
- means including one gas passage extending between said gas inlet and said governor for feeding compressed gas to said motor through said speed-control valve, whereby said motor is operated at or below said predetermined speed;
- means including a normally closed bypass valve and another gas passage extending between said inlet and said motor around said speed-control valve for feeding compressed gas directly to said motor, whereby said speed-control valve and said motor can operate at greater than said predetermined speed;
- a normally closed slow valve in said one passage;
- and
- an operating member displaceable in one direction to open said bypass valve and in another direction to open said slow valve.
7 more elements
A pneumatic hand tool comprising:
- a housing having a compressed-gas inlet;
- pneumatically powered motor in said housing;
- a tool holder on said housing connected to said motor;
- a governor in said housing connected to said motor;
- a speed-control valve in said housing closable by said governor on said motor reaching a predetermined speed;
- means including one gas passage extending between said gas inlet and said governor for feeding compressed gas to said motor through said speed-control valve whereby said motor is operated at or below said predetermined speed;
- means including another gas passage extending between said inlet and said motor around said speed-control valve and a slide-type bypass valve connected between said passages and movable between a slow position connecting said inlet exclusively with said one passage and a fast position connecting said inlet exclusively with said other passage for feeding compressed gas directly to said motor, whereby said speed-control valve is bypassed and said motor can operate at greater than said predetermined speed;
- and
- a main valve between said inlet and both of said passages.
6 more elements
A pneumatic hand-tool comprising:
- a housing having a compressed-gas inlet;
- a pneumatically powered motor in said housing;
- a tool holder on said housing connected to said motor;
- a governor in said housing connected to said motor;
- a speed-control valve in said housing closable by said governor on said motor reaching a predetermined speed;
- means including one gas passage extending between said gas inlet and said governor for feeding compressed gas to said motor through said speed-control valve, whereby said motor is operated at or below said predetermined speed;
- means including another gas passage extending between said inlet and said motor around said feed-control valve and a slide-type bypass valve connected between said passages for feeding compressed gas directly to said motor, whereby said speed-control valve is bypassed and said motor can operate at greater than said predetermined speed;
- a main valve between said inlet and both of said passages;
- a spring normally urging said bypass valve into a closed condition with gas flowing through said speed-control valve;
- and
- means for locking said bypass valve in an open condition.
8 more elements
Dependencies are inferred from the claim text.