Fluid ram provided with means for braking the ram piston at the end of its stroke

Claim 2

A hydraulic ram comprising a cylinder having a first end portion and a second end portion, said second end portion being of a larger diameter than saId first end portion, a piston mounted in said cylinder, said piston comprising a first piston portion of relatively small diameter dimensioned to matingly fit in the first end portion of said cylinder and a second piston portion of larger diameter dimensioned to matingly fit in the second end portion of said cylinder, piston rod means extending from said first end portion and being of a smaller diameter than said first piston portion, said piston rod means extending from said cylinder outward through seal means in an end wall of said cylinder, a delivery conduit extending through said cylinder wall and having an inner end defining an inlet communicating with outermost end portions of said first end portion of said cylinder, an auxiliary conduit extending through a portion of the piston rod and the piston providing communication between the outer periphery of the first piston portion and the outer periphery of a portion of the piston rod spaced from said piston in communication with said first cylinder portion as the piston moves toward the first end of the cylinder and calibrated valve means mounted in said auxiliary conduit for permitting fluid from the second cylinder portion on the side of the piston to which the piston rod is connected to flow through the auxiliary conduit in response to the pressure of said fluid in said auxiliary conduit reaching a predetermined value.

Claim 3

A fluid ram comprising a cylinder, a piston-piston rod assembly slidably mounted in said cylinder, an inlet chamber and a delivery chamber in the cylinder each respectively constituting the portions of the cylinder on opposite sides of the piston, an inlet conduit, a delivery conduit, said inlet conduit and said delivery conduit each being respectively connected to first and second opposite end portions of the cylinder for communication with the inlet and delivery chambers, shock absorbing means including an auxiliary chamber in said cylinder operable as the piston moves through an intermediate position in communication with said delivery conduit so that movement of the piston moves fluid from the auxiliary chamber to the delivery conduit with subsequent movement of the piston toward its extreme end position in the first end of the cylinder terminating communication of the auxiliary chamber with the delivery conduit to substantially isolate the auxiliary chamber, a communication conduit formed in the piston-piston rod assembly extending between and connecting said inlet chamber to said delivery conduit, a control valve mounted in said communication conduit, an auxiliary conduit formed in the piston-piston rod assembly connecting the auxiliary chamber and the delivery conduit, a pressure actuated calibrated valve in the auxiliary chamber which opens upon the pressure in the auxiliary chamber reaching a predetermined value, a control piston connected to the control valve for adjusting the opening of said control valve in accordance with pressure applied to the control piston from said auxiliary chamber, and elastic biassing means positioned in and engaging the piston-piston rod assembly and also engaging the control piston for exerting force on the control piston which tends to keep the control valve in its closed position and opposes the force on the control piston caused by the pressure of the fluid contained in the auxiliary chamber.

Claim 4

A fluid ram comprising a cylinder, a piston-piston rod assembly slidably mounted in said cylinder, an inlet chamber and a delivery chamber in the cylinder each respectively constituting the portions of the cylinder on opposite sides of the piston, an inlet conduit, a delivery conduit, said inlet conduit and said delivery conduit each being respectively connected to first and second opposite end portions of the cylinder for communication with the inlet and delivery chambers, shock absorbing means including an auxiliary chamber in said cylinder operable as the piston moves through an intermediate position in communication with said delivery conduit so that movement of the piston moves fluid from the auxiliary chamber to the delivery conduit with subsequent movement of the piston toward its extreme end position in the first end of the cylinder terminating communication of the auxiliary chamber with the delivery conduit to substantially isolate the auxiliary chamber, a communication conduit formed in the piston-piston rod assembly extending between and connecting said inlet chamber to said delivery conduit, a control valve mounted in said communication conduit, an auxiliary conduit formed in the piston-piston rod assembly connecting the auxiliary chamber and the delivery conduit, a pressure actuated calibrated valve in the auxiliary chamber which opens upon the pressure in the auxiliary chamber reaching a predetermined value, a control piston connected to the control valve for adjusting the opening of said control valve in accordance with pressure applied to the control piston from said auxiliary chamber, and elastic biassing means positioned in and engaging the piston-piston rod assembly and also engaging the control piston for exerting force on the control piston which tends to keep the control valve in its closed position and opposes the force on the control piston caused by the pressure of the fluid contained in the auxiliary chamber.

Claim 5

The invention of claim 2 wherein the control piston for adjusting the opening of the control valve is mounted in a cylindrical portion of the auxiliary conduit.

Claim 6

The invention of claim 2 wherein said ram is of the double-action type and additionally including a second auxiliary chamber which, when the piston is adjacent to the second end portion of the cylinder and is closely approaching its extreme possible position in the second end portion of the cylinder, is initially in communication with the inlet conduit and is subsequently isolated from the inlet conduit by a portion of the cylinder and valve means providing at least partial communication of said second aUxiliary chamber with the communication conduit through said control valve.

Claim 7

The invention of claim 4 wherein said second auxiliary chamber is formed in a hollow auxiliary piston mounted in said inlet chamber and additionally including slide support means on said piston slidably supporting said auxiliary piston and a non-return valve connected between said second auxiliary chamber and the inlet chamber so as to allow passage of fluid from the inlet chamber to said second auxiliary chamber.