US 4,033,569 AGranted

Deformation-preventing workpiece-holding fixture for machine tools

OwnerGarf L. Dunninventor

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Abstract

For holding while machining the end enlargement or enlargements of an elongated otherwise thin deformable workpiece, such as a jet engine blade, the lower block of a two-part hinged fixture has mechanically-adjustable stops which predetermine the location of the front edge and front end of the thin portion of the workpiece and has three upwardly-inclined support pins upon which the lower surface of the thin portion rests. An upper block hinged to the lower block contains three downwardly-inclined correspondingly located clamping pins which bear upon the upper surface of the thin portion immediately above the lower support pins. Each block contains horizontally-movable forward and rearward hold-fast pins for the workpiece end enlargements. A multiplicity of pairs of aligned hydraulically-actuated upper and lower deformation-preventing plungers in both the lower and upper blocks are then set in motion to press simultaneously against the upper and lower surfaces of the thin portion of the workpiece while forward and rearward lower and upper plungers are urged outward against its opposite ends by spring pressure and locked hydraulic pressure fluid created by rotating a screw-threaded piston against hydraulic fluid already present in the upper and lower blocks of the fixture and communicating with the hydraulically-actuated deformation-preventing plungers through upper and lower networks of passageways. The clamping plungers are hydraulically-actuated (FIGS. 1 to 5), or spring-actuated (FIGS. 6 and 7), or screw actuated (FIG. 8).

A deformation-preventing pressure-equalizing fixture for holding, in a machine tool during machining, a workpiece having a first end enlargement to be machined and having a thinner deformable portion adapted to be gripped by said fixture during such machining, said fixture comprising

a block structure having a cavity therein adapted to receive the thinner deformable portion of said workpiece and having an end opening adapted to expose the end enlargement of the workpiece externally of said opening for machining,
said block structure holding a base block and a cover block and a pivot element hingedly interconnecting said blocks and a locking device adapted to releasably lock said blocks together,
a plurality of longitudinally-spaced edge stops and an end stop disposed in one of said blocks and projecting into said cavity and adapted to engage an edge and an end respectively of the thinner deformable portion of said workpiece,
a plurality of workpiece support members disposed in spaced relationship to one another in said base block and projecting upward into said cavity and adapted to engage and support the bottom of the workpiece portion,
a plurality of workpiece clamping members disposed in spaced relationship to one another in said cover block and projecting downward into said cavity with their lower ends disposed substantially in alignment with the upper ends of said support members and adapted to engage the top of the thinner deformable workpiece portion and hold the same down against said workpiece support members,
means for urging said clamping members downward into such engagement with the thinner deformable workpiece portion,
lower and upper sets of lower and upper pressure-equalizing hydraulic plungers of each set disposed in longitudinally-spaced and laterally-spaced relationship and with the upper hydraulic plungers aligned with corresponding lower hydraulic plungers and adapted to engage aligned locations on the top and bottom of the thinner deformable workpiece portion,
and a first hydraulic pressure fluid generator hydraulically connected to said pressure-equalizing plungers.

5 more elements

Abstract

Claims15