US 12,216,093 B1
Material testing system having improved hydraulic wedge grips
James M Greer, Jr., Colorado Springs, CO (US)
Assigned to United States of America as represented by the Secretary of the Air Force, Wright-Patterson AFB, OH (US)
Filed by Government of the United States, as represented by the Secretary of the Air Force, Wright-Patterson AFB, OH (US)
Filed on Oct. 28, 2022, as Appl. No. 17/975,846.
Application 17/975,846 is a continuation of application No. 17/034,006, filed on Sep. 28, 2020, granted, now 11,525,762.
Claims priority of provisional application 63/079,656, filed on Sep. 17, 2020.
This patent is subject to a terminal disclaimer.
Int. Cl. G01N 3/04 (2006.01); G01N 3/08 (2006.01); G01N 3/10 (2006.01)
CPC G01N 3/04 (2013.01) [G01N 3/10 (2013.01); G01N 3/08 (2013.01); G01N 2203/04 (2013.01); G01N 2203/0411 (2013.01); G01N 2203/0441 (2013.01); G01N 2203/0447 (2013.01)] 11 Claims
OG exemplary drawing
 
1. 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.