Material testing system having improved hydraulic wedge grips
AssigneeThe United States of America as represented by the Secretary of the Air Force
InventorJames M Greer, Jr.
Life of this patent
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Abstract
A material testing system that uses at least one hydraulic grip is improved with cable clips that are attachable to a respective lateral side of each hydraulic grip wedge. Each cable clip has another end that extends to engage a cable(s) extending from a corresponding wedge retention spring hole. The cable(s) enable manual extension of a wedge retention spring for engagement and disengagement from the hydraulic grip wedge. The cable clip maintains the cable in a noninterfering position during operational use of the material testing system.
Claims11
A material testing system comprising:
- a load frame comprising:
- a base positioned on a support surface,
- a main actuator supported by the base and below a lower attachment fixture that is actuated by the main actuator, and
- an upper fixture that is held at a distance from the lower attachment fixture;
- and
- at least one hydraulic grip that receives one end of a test specimen and that is positioned between and attached to one of:
- (i) the lower attachment fixture and the upper fixture and comprising:
- a fixture body having a wedge recess,
- a pair of hydraulic grip wedges received in opposition within the wedge recess, each hydraulic grip wedge having a pair of wedge retention spring holes that are intersected respectively by a retention bolt hole,
- four retention springs having one end attached to the fixture body and another end extending upward respectively in the wedge retention spring holes,
- a cable engaged to the other end respectively of each extension spring and extending out of the corresponding hydraulic grip wedge, enabling manual extension of the respective retention spring,
- at least two spring retention bolts received respectively in the retention bolt holes to attach to the other end of the wedge retention spring during extension by the corresponding cable, and
- four or more cable clips that are respectively attached at one end to a lateral side of one of the pair of hydraulic grip wedges and engaged at another end to a corresponding cable to maintain the cable in a noninterfering position.
A method comprising:
- attaching a fixture body of a hydraulic grip to one of a lower attachment fixture atop a main actuator and an upper attachment fixture attached to a crosshead of a load frame;
- attaching four wedge retention springs to a recess of the fixture body;
- passing respective one or more cables attached to each wedge retention spring through a corresponding wedge retention spring hole in one of a pair of hydraulic grip wedges;
- with a respective wedge retention spring extended in the wedge retention spring hole by manual actuation of a corresponding cable;
- inserting a retention spring retention bolt through a bolt hole that intersects the wedge retention spring hole;
- attaching one end of a cable clip respectively to each lateral side of the pair of hydraulic grip wedges;
- engaging another end of the cable clip to a corresponding cable to maintain the cable in a noninterfering position;
- engaging a test specimen between the pair of hydraulic grip wedges;
- and
- actuating the main actuator to materially test the test specimen.
Dependencies are inferred from the claim text.