Filler plates are necessary for all universal testing machines with in-head grip pockets whether they use pinion grip actuators or hydraulic lever arm actuators. Filler plates allow the grip jaw opening to be adjusted to allow testing a range of specimen thicknesses. Adding filler plates allows the grip jaws to close earlier, and grip a thinner specimen, while removing filler plates allows the grip jaws to open wider and grip thicker specimens.
Filler plates are essential for preventing the grip jaws from protruding from the grip pocket while still allowing full use of the grip jaw range.
Grip jaw hangers are used only with hydraulic lever arm grips. It is recommended that one set of hangers be purchased for each set of grip jaws. This allows switching from one set of jaws or jaw type to another without removing the hangers from the grip jaw. This reduces the time and effort required to change the grip jaws on hydraulic lever arm equipped frames.
Note: One set of hangers are included with hydraulic lever arm grips.
Principle Of Operation
Filler plates are inserted between the angled portion of the grip jaw and the angled portion of the grip pocket. The filler plates rest on the top side of each crosshead. For proper grip jaw positioning, an equal number of filler plates should be used in both the upper and lower heads. Various thicknesses are available depending on the frame capacity. Filler plates are easily replaced and minimize wear on the grip pocket which will extend the life of the crosshead grip pocket.
Grip jaw hangers are bolted to the top of each grip jaw used with hydraulic lever arm grip actuators. A rod passes through the lever arm and through each grip hanger. The hanger then transmits the pivoting motion of the lever arm into a linear motion of the grip jaw. The grip hangers are clearanced so that the pivot bar of the hydraulic actuator does not interfere with self tightening action of the wedge grip pocket and jaws as the load is increased on the tensile specimen.
- Filler plates allow adjustment of grip jaw opening to maintain in-head grips inside the pocket
- Additional hangers allow quicker changeout of grip jaws when using hydraulic grip actuators