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STANDARD TENSILE
WEDGE GRIPS
There are two basic types of mechanical
wedge grips. Either the grip bodies move and the wedges remain
stationary while being tightened on the specimen, or the wedges move as
they tighten on the specimen and the bodies of the grips remain
stationary. In Wyoming Test Fixtures, Inc. terminology, the former are
termed “standard grips” and the latter are termed “simple grips“.
The “standard” wedge grips, because the
wedges do not move axially relative to the specimen during clamping, do
not have the potential of putting the tensile specimen in compression,
possibly damaging it as they are tightened. This is obviously a more
desirable condition in general. However, the “simple” wedge grips, discussed in Products Section E-2, are shorter in overall length (and thus better able to fit into confined spaces), and are slightly
easier to fabricate and thus are slightly less expensive.
Fig. 1 shows a pair of
standard tensile wedge grips, representing one of the many load capacity and specimen
size tensile wedge grips that are available.
Fig. 1 Pair of 30,000 lb. Capacity Standard Tensile Wedge
Grips,
3” Wide Grip Faces, 2.25” Grip Length, Instron Type Dm End Fittings
Fig. 2 shows a pair of grips of the same 30,000 lb. capacity, but with 1" wide grip faces. The grip bodies are correspondingly only 1" wide, resulting in them being wider and taller to accommodate the induced stresses when loaded.
Fig. 2 Pair of 30,000 lb. Capacity Standard Tensile Wedge Grips,
1" Wide Grip Faces, 2.25" Grip Length, Instron Type Dm End Fittings
For comparison, Fig. 3 shows a 2" wide wedge grip, rated for only 10,000 lb. capacity. The more compact grip body relative to that of Fig. 2 will be noted. The end connection is a male thread, with lock ring. The wedge grip inserts have diamond serrations
Fig. 3 10,000 lb. Capacity Standard Tensile Wedge Grip,
2" Wide Grip Faces, 2.25" Grip Length, Diamond Serration
Grip Faces, Male Thread End Fitting with Lock Ring |
