Traversing workholding clamp

Claim 2

A traversing workholding clamp comprising, a base, a body mounted for pivotal movement on said base, first and second passages in said body, a clamp arm positioned in said first passage for reciprocal movement between operative and inoperative positions in said body, first spring means for biasing said arm to an inoperative position, a cylindrical bore in said clamp arm having a predetermined cross sectional area, a hollow guide tube connecting said second passage to said bore, a piston positioned within said second passage for movement toward said base to pivot said body on said base, said piston having an annular shoulder providing a reduced cross sectional area actuating surface spaced from the end of said piston, second springs means for biasing the end of said piston into abutting engagement with the end of said second passage, the hydraulic force required to act on the cross sectional area of said bore to move said clamp arm being less than the hydraulic force required to act on the shoulder to move the piston, and hydraulic means for applying fluid pressure to said second passage, whereby the pressure of the fluid acting on the cross sectional area of said bore moves the clamp arm to the operative position prior to the movement of said piston toward said base.

Claim 3

The clamp according to claim 1 including means for holding said clamp arm in a generally fixed rotary position in said passage.

Claim 4

A workholding clamp for holding a workpiece in a fixed position on a work surface, said clamp including, a base adapted to be mounted on the work surface, a body having first and second passages therein, means for pivotally mounting said body on said base, a piston mounted in said second passage for movement toward said base to pivot said body from an inoperative position to an operative position with respect to said workpiece, said piston includes a reduced diameter section and an annular shoulder in said second passage, second spring means for biasing the end of said reduced diameter section into engagement with the end of said second passage, a clamp arm mounted in said first passage for movement from a retracted position to an extended position for operative engagement with said workpiece, first spring means for biasing said clamp arm toward the retracted position, a cylindrical bore in said clamp arm terminating at an operating surface, a hollow guide tube connecting said second passage to said bore, the fluid force required to act on the end of said bore to move the clamp arm to the extended position being less than the fluid force required to act on the shoulder to pivot the valve body, a clamp assembly secured to said clamp arm, means for applying the high pressure fluid to said second passage whereby the pressure of the fluid acting on the end of said bore moves said clamp arm to the extended position prior to the movement of said piston toward said base.

Claim 5

A workholding clamp for holding a workpiece in a fixed position on a work surface, said clamp including, a base adapted to be mounted on the work surface, a body having first and second passages therein, means for pivotally mounting said body on said base, a piston mounted in said second passage for movement toward said base to pivot said body from an inoperative position to an operative position with respect to said workpiece, said piston includes a reduced diameter section and an annular shoulder in said second passage, second spring means for biasing the end of said reduced diameter section into engagement with the end of said second passage, a clamp arm mounted in said first passage for movement from a retracted position to an extended position for operative engagement with said workpiece, first spring means for biasing said clamp arm toward the retracted position, a cylindrical bore in said clamp arm terminating at an operating surface, a hollow guide tube connecting said second passage to said bore, the fluid force required to act on the end of said bore to move the clamp arm to the extended position being less than the fluid force required to act on the shoulder to pivot the valve body, a clamp assembly secured to said clamp arm, means for applying the high pressure fluid to said second passage whereby the pressure of the fluid acting on the end of said bore moves said clamp arm to the extended position prior to the movement of said piston toward said base.

Claim 6

The clamp according to claim 3 including means for limiting the movement of said clamp arm to axial movement.

Claim 7

The workholding clamp according to claim 3 including an axially extending groove in the outer surface of said clamp arm and a ball fixed in said second passage for engagement with said groove to provide axial movement of said clamp arm.