GB756790A - Improvements in or relating to a universal apparatus for testing the mechanical properties of metals by alternative bending of a test piece - Google Patents

Abstract

756,790. Testing physical qualities of metals by bending. MIRONOFF, N., and ATELIERS DES CHARMILLES SOC. ANON. May 31, 1954 [June 8, 1953], No. 16021/54. Class 106 (2). [Also in Group XXII] A test piece E, Fig. 1, s supported between two pairs of converging jaws 14, 16 which can effect an angular movement about a common hinge centre 11 formed between two plates 12, 13 on which the jaws are supported, the pair 14 forming guide jaws and the pair 16 clamping the test piece, and a second pair of guiding jaws 15 is provided on.the plate 13 carrying the clamping jaws 16, the jaws 15, 14 cooperating to maintain constant the length of the deformation zone of the test piece and to ensure its symmetrical deformation. Means are also provided to maintain a predetermined ratio between the length of the deformation zone and the thickness of the specimen under test. As shown in Fig. 2, the jaws 15, 15a are pivoted at their rear ends 26, 26a to the transverse bar of a T-shaped lever 27 itself pivoted at 28 to a part 29, Fig. 3, which may be moved longitudinally relatively to the plate 13 by means of a rack 30 engaging a sector 30a on a lever 31 lockable by a screw 32 in adjusted position on the plate 13. Such longitudinal movement of the part 29 is balanced with that of the corresponding part 46 of the jaws 14, 14a by engagement of a groove 44 on the limb 43 of the T-shaped lever 27 with a pin 45 on the corresponding limb 46. The jaws 15, 15a are held in contact with the test piece by means of rollers 34, 34a secured to links 36, 36a pivoted to the spindle 28, the spindles of the rollers also engaging slots 38 in members 39, 39a and can be locked relatively thereto by nuts and levers 41, 41a. The members 39, 39a can pivot relatively to the plate 13 about pivots 40, 40a and be locked relatively thereto by locking screws 47, 47a passing through arcuate slots 48, 48a in the plate. The jaws are urged against the rollers by a spring 42. The angle selected is determined by the required ratio of length of test zone to thickness of test piece and once this ratio is selected and the members 39, 39a adjusted accordingly, the ratio is maintained constant for t-estpieces of different thicknesses. The clamping jaws 16, 16a are secured to the part 29. Similar mounting and adjusting means are provided for the other pair of guide jaws 14, 14a. The plate 12 has an extension to which is secured a weight 18 and the plate 13 has an actuating handle 19. Stops 23 may be engaged in holes 22 on extensions 20, 21 of plate 12 to limit the bending angle in either direction. A graduated plate 24 secured to the frame 10 co-operates with an index 25 on the plate 12 to indicate the bending angle.