Flow control device

A fluid cylinder for extending and retracting a piston in response to fluid flow, the cylinder being adaptable for connection to a workpiece holder and comprising:

• a cylinder housing for housing the piston, the piston being extendable and retractable along and within said housing in response to the fluid flow;
• a backing plate at one end of said housing, said backing plate having at least one port for fluid flow therethrough and a recess having an inner wall portion interconnected with said at least one port and a side wall portion extending from said inner wall portion toward said cylinder housing;
• and
• a flow control apparatus positionable within said recess and comprising:
• a flow restricting member positioned at said inner wall portion of said recess, said flow restricting member having a first passageway and a sealing surface;
• and
• a flexible sealing member having a body portion and a sealing portion, said body portion being engaged with said side wall of said recess and said sealing portion being positioned around said sealing surface of said flow restricting member for sealing engagement with said sealing surface, said sealing portion being movable from said sealing surface to at least occasionally define a second passageway therebetween in response to fluid flow in a first direction;
• wherein said sealing member is movable to disengage said sealing surface in response to fluid flow in said first direction such that fluid flows through said first and second passageways in said first direction, said sealing member being movable to engage said sealing surface in response to fluid flow in a second direction to limit fluid flow through said second passageway in said second direction, said flow control apparatus thereby restricting fluid flow in said second direction to control operation of said fluid cylinder.

A fluid cylinder for extending and retracting a piston in response to fluid flow, the cylinder being adaptable for connection to a workpiece holder and comprising:

• a cylinder housing for housing a piston, said piston being extendable along and within said housing in response to fluid flow in a first direction and being retractable along and within said housing in response to fluid flow in a second direction;
• a backing plate at one end of said housing, said backing plate having at least one port for fluid flow therethrough and a recess having an inner wall portion interconnected with said at least one port and a side wall portion extending from said inner wall portion toward said cylinder housing;
• and
• a flow control apparatus positionable within said recess and comprising:
• a flow restricting member positioned at said inner wall portion of said recess, said flow restricting member having a base portion, a first passageway and a sealing surface, said base portion defining a connecting passageway extending laterally thereacross and which is generally normal to said first passageway and in fluid communication with said first passageway;
• and
• a flexible sealing member having a body portion and a sealing portion, said body portion being engaged with said side wall of said recess and said sealing portion being positioned around said sealing surface of said flow restricting member for sealing engagement with said sealing surface, said sealing portion being movable from said sealing surface to at least occasionally define a second passageway therebetween in response to fluid flow in said first direction;
• wherein said flow restricting member and said sealing member are cooperatively operable to allow fluid flow in said first direction from said at least one port through said connecting passageway and further through said first passageway and said second passageway, said flow restricting member and said sealing member being further cooperatively operable to allow fluid flow in a second direction through said first passageway and further through said connecting passageway to said at least one port, said sealing member being movable to engage said sealing surface in response to fluid flow in said second direction to limit fluid flow between said sealing member and said sealing surface in said second direction, said flow control apparatus thereby restricting fluid flow in said second direction to control operation of said fluid cylinder.