Hydraulically actuated grips (20) are constructed to permit loading of specimens (13) from the side of the grip jaws (33). The grip jaws (33) are particularly adapted for use with flat specimens, are easily actuated, and are designed so that when actuated the grip jaws (33) do not exert any substantial axial load on the specimen being loaded.

Side loading specimen grips

This hydraulic chucking head, especially for testing machines wherein the test sample must be held without play in the direction of load application, includes at least two test sample holding pistons movable along a common axis toward each other and toward a central axis through the chucking head. These pistons are hollow inside and movable in respective cylinders in the housing with a certain initial play. The piston walls or jackets are elastically yielding when the pressure inside the piston is increased, whereby the test sample is held and simultaneously said play is removed since the piston walls are pressed against the respective cylinder bores. Preferably a non-metallic coating is provided between the piston walls and the cylinder bores which coating acts as a sealing and reduces friction.

Hydraulic chucking head

The apparatus for the mechanical testing of materials and especially fiber-reinforced plastics, to determine the pressure characteristic value on pressure along a single axis, has a lower clamping block (5) and a parallel upper clamping block (6) with an axial sliding movement along at least one guide column (9). Each clamping block has a set of clamping pads (2,3). Each with a fixed pad (2.1,2.2) and a moving pad (3.1,3.2) operated by a hydraulic cylinder (4.1,4.2). The sample workpiece (1) is clamped with an equal force at both ends, with a test shear force applied to it through the sets of clamping pads.

Apparatus for mechanical testing of fiber-reinforced materials to determine pressure characteristic values, has clamping pads at clamping blocks operated by hydraulic cylinders on both workpiece ends

The disclosure relates to a specimen holder for a grip used in materials, or similar testing. The user can position a specimen or testing sample within the open jaw, and then remove his or her hands to a safe location before activating the grip to grip the specimen.

Grip-mounted specimen holder

A fluid pressure operated workholding system particularly adapted to securely maintain a workpiece in a desired position during a manufacturing operation, including a source of first pressurized fluid, a first fluid conduit means communicating this source with a pressure pump and control means, and a second fluid conduit means communicating the pressure pump and control means with a workholder means having a fluid pressure responsive means which may be disposed about the workpiece to be held. The pressure pump and control means is divided into separate, variable volumes by a piston means mounted for movement within it in response to pressure exerted on it by the first fluid, and moves to force a second fluid contained in one of the volumes, through the second conduit means to the workholder means to expand the means responsive to fluid pressure to contact and hold the workpiece at a pressure determined by a means biasing the piston means. A work positioning system in which separate pressure pump and control means are in communication with opposite sides of a piston means in a positioning chamber to move the piston means relative to the difference in pressure exerted on opposite sides thereof, through each pressure pump and control means, to incrementally feed and position material.

Ludwig Engelbrecht

Papers

Test piece centering means for stress-strain machines

Vorrichtung zum achsgerechten zentrieren und einspannen von pruefstuecken