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A double acting pneumatic motor having a cylinder, a piston within the cylinder that divides the cylinder into two cavities that vary in volume with movement of the piston, a source of fluid under pressure, and a valve assembly for alternately directing fluid to one cavity while exhausting the other

A double acting pneumatic motor having a cylinder, a piston within the cylinder that divides the cylinder into two cavities that vary in volume with movement of the piston, a source of fluid under pressure, and a valve assembly for alternately directing fluid to one cavity while exhausting the other cavity to make the piston reciprocate. The valve assembly resides in a housing, and includes a cylindrical spool that moves axially between two positions with at least one enlarged diameter portion between smaller diameter portions at each end. The pneumatic motor may be provided with a cover for attenuating sound from the exhaust.

대표청구항 ▼

1. A reciprocating piston and cylinder device for driving a moveable member, comprising:a hollow cylinder having one closed end, one end with an opening, and a longitudinal axis; a piston disposed for axial movement within the cylinder over a range of motion, sealingly engaging the inside surface of

1. A reciprocating piston and cylinder device for driving a moveable member, comprising:a hollow cylinder having one closed end, one end with an opening, and a longitudinal axis; a piston disposed for axial movement within the cylinder over a range of motion, sealingly engaging the inside surface of the cylinder to define a first variable volume cavity on one side of the piston and a second variable volume cavity on the other side of the piston, the piston including a piston rod sealingly extending through the opening in the second end of the cylinder and adapted to be attached to the moveable member; a source of fluid under pressure; and a valve assembly for alternately directing fluid to one cavity while exhausting the other cavity to cause reciprocation of the piston in the cylinder, the valve assembly comprising: a hollow housing having a cylindrical inside surface, a longitudinal axis, and two closed ends; a first passage between the housing and the first cavity and a second passage between the housing and the second cavity, placing the housing in continuous fluid communication with each cavity; a substantially cylindrical main valve member that is disposed for axial movement within the housing, movable to a first position directing fluid under pressure to the first passage and exhausting the second passage and a second position directing fluid under pressure to the second passage and exhausting the first passage, the main valve member having a central bore therethrough at least a portion of which continuously communicates with the pressurized fluid source and having at least one portion with an enlarged diameter spaced from the ends of the main valve member and interposed between a smaller diameter portion at each end; first and second variable volume fluid pressure chambers on opposite sides of the at least one enlarged diameter portion of the main valve member; a pilot valve coaxial with and disposed substantially within the central bore of the main valve member and axially movable to a pilot valve first position for directing fluid under pressure to the first chamber and exhausting the second chamber to impel the main valve member to the main valve member first position, and movable to a pilot valve second position for directing fluid under pressure to the second chamber and exhausting the first chamber to impel the main valve member to the main valve member second position; and means for moving the pilot valve, whereby the position of the pilot valve determines the position of the main valve member, and the position of the main valve member determines which cavity is pressurized, which cavity is exhausted, and the direction of motion of the piston.