Press system or the like

A press system or the like comprising hydraulic cylinder means for applying force to a member, said hydraulic cylinder means including a relatively movable piston and cylinder which cooperate to define a variable volume cylinder chamber, means for supplying hydraulic fluid under pressure to said cylinder chamber to effect relative movement between said piston and cylinder and an increase in the volume of said variable volume cylinder chamber, conduit means connected in fluid communication with said variable volume cylinder chamber for conducting hydraulic fluid from said variable cylinder chamber to effect a decrease in the volume of said variable volume cylinder chamber, valve means connected in fluid communication with said conduit means for at least partially controlling the flow of hydraulic fluid from said variable volume cylinder chamber, said valve means including housing means for at least partially defining first and second valve chambers, each of said valve chambers having a hydraulic fluid inlet connected in fluid communication with said cylinder chamber by said conduit means and a hydraulic fluid outlet, a first valve member disposed in said housing means and movable between a closed position and an open position, said first valve member in said closed position being effective to block hydraulic fluid flow between said hydraulic fluid inlet to said first valve chamber and said hydraulic fluid outlet for said first valve chamber to block hydraulic fluid flow from said cylinder chamber through said first valve chamber, said first valve member in said open position being effective to enable hydraulic fluid from said cylinder chamber to flow between said hydraulic fluid inlet to said first valve chamber and said hydraulic fluid outlet for said first valve chamber to enable hydraulic fluid to flow from said cylinder chamber through said first valve chamber first variable volume chamber means for holding fluid under pressure, said first valve member being urged toward the closed position under the influence of the fluid pressure in said first variable volume chamber means, said first valve member being movable from the closed position to the open position under the influence of the pressure of hydraulic fluid in said first valve chamber and against the influence of the fluid pressure in said first variable volume chamber means when the hydraulic fluid pressure in said cylinder chamber exceeds a first predetermined pressure, said first valve member being effective upon movement from the closed position to the open position to effect a reduction in the volume of said first variable volume chamber means, a second valve member disposed in said housing means and movable between a closed position and an open position, said second valve member in said closed position being effective to block hydraulic fluid flow between said hydrauic fluid inlet to said second valve chamber and said hydraulic fluid outlet for said second valve chamber to block hydraulic fluid flow from said cylinder chamber through said second valve chamber, said second valve member in said open position being effective to enable hydraulic fluid from said cylinder chamber to flow between said hydraulic fluid inlet to said second valve chamber and said hydraulic fluid outlet for said second valve chamber to enable hydraulic fluid to flow from said cylinder chamber through said second valve chamber, second variable volume chamber means for holding fluid under pressure, said second valve member being urged toward the closed position under the influence of the fluid pressure in said second variable volume chamber means, said second valve member being movable from the closed position to the open position under the influence of the pressure of hydraulic fluid in said second valve chamber and against the influence of the fluid pressure in said second variable volume chamber means when the hydraulic fluid pressure in said cylinder chamber exceeds a second predetermined pressure, said second valve member being effective upon movement from the closed position to the open position to effect a reduction in the volume of said second variable volume chamber means, and control means for blocking fluid flow from said cylinder chamber to said second valve chamber during one portion of the relative movement between said piston and cylinder to prevent relieving of the fluid pressure in said cylinder chamber by a flow of hydraulic fluid through said second valve chamber, said control means being effective to enable fluid to flow from said cylinder chamber to said second valve chamber during another portion of the relative movement between said piston and cylinder to enable the fluid pressure in said cylinder chamber to be at least partially relieved by a flow of hydraulic fluid through said second valve chamber.

A press system or the like comprising hydraulic cylinder means for applying force to a member, said hydraulic cylinder means including a relatively movable piston and cyliner which cooperate to define a variable volume cylinder chamber, means for supplying hydraulic fluid under pressure to said cylinder chamber to effect relative movement between said piston and cylinder and an increase in the volume of said variable volume cylinder chamber, conduit means connected in fluid communication with said variable volume cylinder chamber for conducting hydraulic fluid from said variable cylinder chamber to effect a decrease in the volume of said variable volume cylinder chamber, valve means connected in fluid communication with said conduit means for at least partially controlling the flow of hydraulic fluid from said variable volume cylinder chamber, said valve means including a housing which at least partially defines a valve chamber having a hydraulic fluid inlet connected in fluid communication with said cylinder chamber by said conduit means and a hydraulic fluid outlet, a valve member disposed in said housing and movable between a closed position blocking hydraulic fluid flow from said hydraulic fluid inlet to said hydraulic fluid outlet to thereby block hydraulic fluid flow from said cylinder chamber and an open position enabling hydraulic fluid to flow from said hydraulic fluid inlet to said hydraulic fluid outlet to thereby enable hydraulic fluid to flow from said cylinder chamber, variable volume chamber means for holding fluid under pressure, said valve member being urged toward the closed position under the influence of the fluid pressure in said variable volume chamber means, said valve member being movable from the closed position to the open position under the influence of the pressure of hydraulic fluid in said valve chamber and against the influence of the fluid pressure in said variable volume chamber means when the hydraulic fluid pressure in said cylinder chamber exceeds a predetermined pressure to effect at least partial relieving of the hydraulic fluid pressure in said cylinder chamber, said valve member being effective upon movement from the closed position to the open position to effect a reduction in the volume of said variable volume chamber means, and means for varying the fluid pressure in said variable volume chamber means to vary the force urging said valve member toward the closed position and the hydraulic fluid pressure required in said valve and cylinder chambers to effect movement of said valve member from the closed position to the open position, said means for varying the fluid pressure in said variable volume chamber means includes means for varying the fluid pressure in said variable volume chamber means during relative movement between said piston and cylinder and as a function of the extent of relative movement between said piston and cylinder.

A press system or the like comprising hydraulic cylinder means for applying force to a member, said hydraulic cylinder means including a piston and cylinder which are relatively movable through an operating stroke to vary the volume of a variable volume cylinder chamber defined by said piston and cylinder, means for supplying hydraulic fluid under pressure to and conducting hydraulic fluid from said cylinder chamber to effect relative movement between said piston and cylinder and a variation in the volume of said variable volume cylinder chamber, valve means connected in fluid communication with said variable volume cylinder chamber for maintaining at least a first fluid pressure in said variable volume cylinder chamber during a first portion of an operating stroke and for maintaining at least a second fluid pressure in said variable volume cylinder chamber during a second portion of an operating stroke, said valve means including a housing which at least partially defines a valve chamber having a hydraulic fluid inlet connected in fluid communication with said cylinder chamber and a hydraulic fluid outlet, a valve member disposed in said housing and movable between a closed position blocking hydraulic fluid flow from said hydraulic fluid inlet to said hydraulic fluid outlet to thereby block hydraulic fluid flow from said cylinder chamber and an open position enabling hydraulic fluid to flow from said hydraulic fluid inlet to said hydraulic fluid outlet to thereby enable hydraulic fluid to flow from said cylinder chamber, pressure chamber means for holding a fluid under pressure, said valve member being urged toward the closed position under the influence of the fluid pressure in said pressure chamber means, said valve member being movable from the closed position to the open position under the influence of the pressure of hydraulic fluid in said valve chamber and against the influence of the fluid pressure in said pressure chamber means, and means for varying the fluid pressure in said pressure chamber from one fluid pressure during said first portion of an operating stroke to another fluid pressure during said second portion of an operating stroke to vary the force urging said valve member toward the closed position and the magnitude of the hydraulic fluid pressure required in said valve chamber to effect movement of said valve member from said closed position to said open position, said means for varying the fluid pressure in said pressure chamber including means for varying the fluid pressure as a function of the extent of relative movement between said piston and cylinder.

A press system or the like comprising hydraulic cylinder means for applying force to a member, said hydraulic cylinder means including a piston and cylinder which are relatively movable through an operating stroke to vary the volume of a variable volume cylinder chamber defined by said piston and cylinder, means for supplying hydraulic fluid under pressure to and conducting hydraulic fluid from said cylinder chamber to effect relative movement between said piston and cylinder and a variation in the volume of said variable volume cylinder chamber, valve means connected in fluid communication with said variable volume cylinder chamber for maintaining at least a first fluid pressure in said variable volume cylinder chamber during a first portion of an operating stroke and for maintaining at least a second fluid pressure in said variable volume cylinder chamber during a second portion of an operating stroke, said valve means including a housing which at least partially defines a valve chamber having a hydraulic fluid inlet connected in fluid communication with said cylinder chamber and a hydraulic fluid outlet, a valve member disposed in said housing and movable between a closed position blocking hydraulic fluid flow from said hydraulic fluid inlet to said hydraulic fluid outlet to thereby block hydraulic fluid flow from said cylinder chamber and an open position enabling hydraulic fluid to flow from said hydraulic fluid inlet to said hydraulic fluid outlet to thereby enable hydraulic fluid to flow from said cylinder chamber, pressure chamber means for holding a fluid under pressure, said valve member being urged toward the closed position under the influence of the fluid pressure in said pressure chamber means, said valve member being movable from the closed position to the open position under the influence of the pressure of hydraulic fluid in said valve chamber and against the influence of the fluid pressure in said pressure chamber means, and means for varying the fluid pressure in said pressure chamber from one fluid pressure during said first portion of an operating stroke to another fluid pressure during said second portion of an operating stroke to vary the force urging said valve member toward the closed position and the magnitude of the hydraulic fluid pressure required in said valve chamber to effect movement of said valve member from said closed position to said open position, said means for varying the fluid pressure includes means for gradually varying the fluid pressure in said pressure chamber from said one fluid pressure to said other fluid pressure during an operating stroke, said means for gradually varying the fluid pressure includes a cam member which is moved upon relative movement between said piston and cylinder and follower means for effecting a change in the fluid pressure in said pressure chamber in response to movement of said cam member.

A press system or the like comprising hydraulic cylinder means for applying force to a member, said hydraulic cylinder means including a relatively movable piston and cylinder which cooperate to define a variable volume cylinder chamber, means for supplying hydraulic fluid under pressure to said cylinder chamber to effect relative movement between said piston and cylinder and an increase in the volume of said variable volume cylinder chamber, conduit means connected in fluid communication with said variable volume cylinder chamber for conducting hydraulic fluid from said variable cylinder chamber to effect a decrease in the volume of said variable volume cylinder chamber, valve means connected in fluid communication with said conduit means for at least partially controlling the flow of hydraulic fluid from said variable volume cylinder chamber, said valve means including a housing which at least partially defines a valve chamber having a hydraulic fluid inlet connected in fluid communication with said cylinder chamber by said conduit means and a hydraulic fluid outlet, a valve member disposed in said housing and movable between a closed position blocking hydraulic fluid flow from said hydraulic fluid inlet to said hydraulic fluid outlet to thereby block hydraulic fluid flow from said cylinder chamber and an open position enabling hydraulic fluid to flow from said hydraulic fluid inlet to said hydraulic fluid outlet to thereby enable hydraulic fluid to flow from said cylinder chamber, said valve means including a rigid sintered metal member disposed in said valve chamber and defining a plurality of small porous openings through which hydraulic fluid must pass in flowing from said hydraulic fluid inlet to said hydraulic fluid outlet, said valve member being formed by an imperforate sheet of resiliently flexible material having a major side surface, said major side surface of said sheet being disposed in abutting engagement with said rigid sintered metal member and extending across said plurality of openings to block fluid flow through said openings when said valve member is in the closed position, said sheet being resiliently deflected from the closed position to the open position in which at least a portion of said major side surface is spaced apart from said rigid sintered metal member to enable hydraulic fluid to flow through said plurality of openings when said valve member is in the open position, variable volume chamber means for holding fluid under pressure, said valve member being urged toward the closed position in engagement with said rigid sintered metal member under the influence of the fluid pressure in said variable volume chamber means, said valve member being movable from the closed position to the open position under the influence of the pressure of hydraulic fluid in said valve chamber and against the influence of the fluid pressure in said variable volume chamber means when the hydraulic fluid pressure in said cylinder chamber exceeds a predetermined pressure to effect at least partial relieving of the hydraulic fluid pressure in said cylinder chamber, said valve member being effective upon movement from the closed position to the open position to effect a reduction in the volume of said variable volume chamber means.