Cooper Industries, Inc.

Gardner-denver Company

William Workman, Jr

Joseph F Carter

John R Bos

The present invention relates to a device for shutting off a supply of pressurized motive fluid to an associated fluid driven motor in response to a predetermined motor back pressure indicating a predetermined load on the motor. The device comprises a housing having a fluid inlet connected to a supply of motive fluid and a fluid outlet connected to supply pressurized fluid to the associated fluid driven motor. A passageway extends through the housing between the fluid inlet and the fluid outlet. A shut-off piston is slidably mounted with the housing and is shiftable to close the housing passageway and shut off the supply of pressurized fluid to the motor in response to a predetermined motor back pressure. An orifice of variable size is provided in the housing passageway and is utilized to reduce the pressure of the fluid supplied to the motor. The size of the orifice is controlled by a pilot piston slidably mounted within the housing and shiftable between a first and second position to vary the size of the orifice from a restricted to an open size. The pilot piston is shiftable in response to a predetermined motor back pressure to enlarge the orifice prior to the closing of the shut-off piston. Enlarging the orifice at this time results in an increase in pressure to the motor just prior to shut off. It has been found that this increase in final pressure to the motors permits the final shut-off torque of the motor to be more accurately controlled, regardless of the type of load encountered by the motor.

Shut-off device for a fluid driven motor

A safety shut off mechanism for a fluid-powered motor comprises a reaction torque structure tending the rotate in a direction opposite to the direction of rotation of the motor under load a swing-bar for normally restraining the reaction torque structure against rotation, a reference structure for providing a point of reference as to movement of the reaction torque structure, a locking structure actuated by fluid pressure for locking the reference structure against rotation, a retaining structure tending to retain the reaction torque structure and the reference structure in a predetermined orientation relative to each other, and a shut-off structure for depriving the motor of the motive force of the fluid in response to relative movement between the reaction torque structure and the reference structure upon failure of the swing-bar.

Safety shut-off for swing bar tools

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 centrifugal 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. An alternate embodiment includes a limited motion coupling between the valve closure member and the motor drive shaft which provides assistance in opening and closing the valve closure member.

Speed responsive motor shutoff mechanism for fluid operated tool

A pneumatic torque tool includes a torque responsive mechanism which actuates a valve closure member by release of an elongated actuating rod. A movable valve seat is biased in a first position by pressure fluid supplied to the tool and upon release of the actuating rod the valve closure member engages the seat to shut off air flow to the tool motor. Upon closure of an operator actuated valve the seat is biased to a second position for resetting the actuating rod and closure member.

Torque responsive motor shutoff mechanism for fluid operated tool

A power tool speed shifting mechanism includes a planetary gear set wherein the ring gear is connected to the driven member of a torque responsive disengageable clutch. The driving clutch member is keyed for rotation with the sun gear of the planetary gear set; and the ring gear is mounted in a one-way clutch to provide for unidirectional rotation of the entire planetary gear set at the speed of the sun gear when the torque responsive clutch is engaged. The one-way clutch is mounted in an axially movable but substantially nonrotatable member of a torque responsive coupling. In response to a predetermined torque being transmitted through the speed shifting mechanism the clutch members disengage to impose a reaction torque on the coupling through the ring gear and the clutch. Axial movement of the one coupling member together with the ring gear holds the clutch disengaged whereby the planet gear carrier then rotates at a reduced speed with respect to the sun gear.

Torque responsive speed shift mechanism for power tool

A low pressure shutoff valve adapted to be interposed in the fluid supply conduit of a fluid operated torque tool comprises a piston closure member having opposed differential pressure faces exposed to fluid supply pressure and a coil spring for biasing the piston toward a fluid shutoff position. The piston is disposed in a chamber which may be vented by actuating an axially slidable sleeve on the exterior of the valve body whereby the valve is opened to supply pressure fluid to the tool as long as the fluid pressure is greater than a predetermined minimum value.

Low pressure shutoff valve for fluid operated tool

A pneumatic power tool for tightening threaded fasteners includes a planetary gear unit in which the ring gear is rotatable against the bias of a torsion coil spring to actuate a motor shutoff control valve at a predetermined torque reaction exerted on the ring gear. The torsion spring is in a substantially relaxed state during fastener rundown and before torque buildup on the fastener regardless of the torque setting at which motor shutoff is to occur. Adjustment of the motor shutoff torque setting is obtained by changing the positional relationship between a control valve pushrod and a cam surface on the ring gear member.

Torque responsive motor shutoff for power tool

A speed shifting mechanism for a pneumatic wrench or nutsetter comprises a planetary gear arrangement in the drive mechanism of the wrench in which the planet gear carrier is connected to the driver clutch member of a torque responsive clutch and the planetary ring gear is mounted in a one way clutch to provide for unidirectional rotation of the ring gear. The torque responsive clutch is of the sloping tooth type and the driving clutch member is connected to a piston having opposing faces and fitted in the tool housing to form opposed fluid chambers. Pressure fluid is admitted to one of the chambers at a controlled pressure to act on the piston for holding the clutch in the engaged condition. Movement of the driving clutch member at torque causes pressure fluid at the controlled pressure to be vented and the opposite chamber to become pressurized thereby acting on the clutch to disengage and enable the planetary gear arrangement to become operative to reduce the output speed of the wrench.

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Spring Lake, MI, United States of America

William Workman, Jr