Pneumatic hand tool with improved control valve
AssigneeBettcher Indusrties, Inc.
InventorsRaymond J. Herrmann, Geoffrey D. Rapp, Shawn A. Mills
Life of this patent
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Abstract
A pneumatic hand tool comprises a tool body communicable with an operating air source, a pneumatic motor supported by the tool body, and a control valve for controlling air flow to the motor. When the control valve is in an open condition the motor is operated to drive the tool. When the valve is in a closed condition it cuts off the supply of operating air to the motor. In the closed condition the control valve communicates with air at ambient atmospheric pressure so that source air leaking from the control valve is vented away from the motor to preclude unintended motor operation.
Claims14
A rotary knife operable from a source of high pressure air comprising:
- a tubular handle assembly;
- an annular blade supported for rotation about a central axis;
- a blade housing supporting said blade;
- a head assembly connected to said handle assembly;
- a pneumatic motor assembly supported by said handle assembly for driving said blade;
- a control valve for controlling the flow of air from the source to the motor assembly, said control valve having an open condition wherein source air is supplied to said motor assembly for operating the motor and a closed condition wherein source air is blocked from reaching the motor assembly, said control valve shiftable into said handle assembly when operated to said open condition and shiftable in a direction away from said handle assembly when operated from its open condition to its closed condition;
- said control valve having an air delivery port defined by a valve seat through which air is directed into said motor assembly when said control valve is in said open condition, said delivery port communicating with atmospheric air when said control valve is in said closed condition so that control valve leakage does not result in unintended knife operation.
A pneumatic hand tool operated from a pressurized air source comprising:
- a tool body;
- a pneumatic motor supported by said tool body for actuating a tool, said motor having an inlet port for receiving air from the source;
- a control valve for controlling the flow of air from the source to the motor, said control valve having an open condition wherein source air is supplied to said motor for operating the tool and a second condition wherein the motor is not operated, said control valve comprising a valve body defining a delivery port through which air is supplied to said motor, a seat surrounding said port, and a valving member movable relative to said seat to open and close said port, said valving member biased toward engagement with said seat to block flow through said port;
- in the open condition of said control valve said control valve body is stationed relative to said tool body in a first position wherein said delivery port communicates directly with said motor inlet port and said valving member is spaced from said seat so that air from said source is communicated to said motor, and in said second condition of said control valve said control valve body is in a second position relative to said tool body where said valving member engages said seat for blocking flow from said source through said delivery port and said delivery port communicates with air at ambient atmospheric pressure so that any source air leaking from said delivery port is vented away from said inlet port.
Dependencies are inferred from the claim text.