GB788836A - Method and apparatus for fatigue testing of elastomers - Google Patents

Abstract

788,836. Testing physical qualities of materials. GOODYEAR TIRE & RUBBER CO. April 16,1956 [Oct. 14, 1955], No. 11475/56. Class 106 (2). Apparatus for testing a sheet specimen 35 of an elastomer includes at least two pairs of specimen-gripping clamps 29, 30, each pair disposed in oppositely spaced relationship along a common axis in the plane of the sheet specimen 35 and with the axis of each successive pair at a substantial angle to the axes of the other pairs, and means to reciprocate the respective clamps 29, 30 toward and from each other in a cyclic manner and in a selected phase relationship collectively to effect multiaxial stresses within the test specimen 35. A motor 9 drives through belt 11 and pulley 8 a shaft 7 to which are keyed two cams 25, 24 followed respectively by pairs of spring-loaded rods 15 sliding in journal blocks 17 beneath a table 4. Crosslinks 26 tie the rods 15 to parallel rods 13 sliding in journal blocks 12 above the table 4 and carrying the clamps 29, 30. Each cam 25, 24 has three keyways so disposed that when an appropriate keyway of each is aligned with the keyway 23 in the shaft 7, the cams will be superimposed in line, or inclined at 45 or 90 degrees (Fig. 4) to reciprocate the clamps 29, 30 in phase, or out of phase by 90 ot 180 degrees. The specimen 35 may be inserted in the clamps when they are in an intermediate position so that the specimen is under tension only part of a cycle and buckled during the remainder. Further clamps and means for reciprocating them may be provided. The shape of the cams may be varied. Continuous variation in phase may be obtained by replacing the keyways by setscrews. A counter may be provided to register the number of cycles to which the specimen is subjected, and heaters or coolers may be mounted near the specimen.