Device for carrying out endurance tests on various test-pieces

Claim 1

AN ENDURANCE TESTING MACHINE COMPRISING A RIGID FRAME, A LONGITUDINALLY RECIPROCABLE SUPPORT MEMBER MOUNTED ON SAID FRAME FOR SECUREMENT TO ONE END OF A TEST PIECE WHOSE OTHER END IS FIXED, SAID SUPPORT MEMBER INCLUDING A PAIR OF SPACED PLATES SECURED TO EACH OTHER BY RIGID MEANS, A FIRST SPRING DEVICE INTERPOSED BETWEEN ONE OF SAID PLATES AND AN ADJUSTABLY POSITIONED MEMBER ON SAID FRAME TO APPLY A FIRST FORCE TO THE SUPPORT MEMBER AND A SECURED TEST-PIECE IN ONE DIRECTION, A SECOND SPRING DEVICE HAVING ONE END BEARING AGAINST THE OTHER OF SAID PLATES TO APPLY A SECOND FORCE TO THE SUPPORT MEMBER IN OPPOSITION TO SAID FIRST FORCE, A FREELY MOUNTED, LONGITUDINALLY DISPOSED ROD BEARING AGAINST THE OTHER END OF SAID SECOND SPRING DEVICE, A THIRD SPRING DEVICE ENGAGED BETWEEN A COLLAR ON SAID ROD AND AS SECOND ADJUSTABLY POSITIONED MEMBER ON SAID FRAME SO AS TO OPPOSED SAID SECOND SPRING DEVICE, MEANS CONNECTED TO SAID ROD FOR OSCILLATING THE ROD LONGITUDINALLY, AND MEANS ON SAID ROD TO ADJUST THE TENSION OF SAID SECOND AND THIRD SPRING DEVICES AND THEREBY SAID SECOND FORCE APPLIED TO THE SUPPORT MEMBER.