Patent GB-718724-A (GB)
Title: Improvements in and relating to apparatus for testing shock absorbers and like vibration dampers
IPC: G01M17/04
Filed: 1951-11-22
Abstract: 718,724. Testing shock absorbers. WOODHEAD COMPONENTS, Ltd., and ONIONS, J. W. Nov. 21, 1952 [Nov. 22, 1951], No. 27451/51. Class 106 (2) An apparatus for testing shock absorbers comprises means for operating a shock absorber in one direction with the simultaneous compression, to a predetermined amount of load, of spring means with which the shock absorber is associated, means permitting a recoil of the spring to effect re-operative movement of the shock absorber in the reverse direction, and means for automatically recording said recoil movement as a function of time upon a chart. In Fig. 1 the apparatus comprises a vertical column 10 on which are two springs 24 and 25 arranged between a slidable sleeve 12 and two fixed collars 26 and 27. A lever 13, pivoted at 14, is used to force the sleeve 12 either upwardly or downwardly to compress the spring 24 or the spring 25 respectively, the lever 13 having a pointed end 17 that eventually disengages itself from a corresponding shaped part 18 on the sleeve 12 to allow the spring that is compressed to return the sleeve 12 to its original position. Mounted between the sleeve 12, Fig. 2, and a fixed collar 35 is the shock absorber 33 to be tested. A pendulum 39 carrying a scriber 38 is pivoted to a further fixed collar 42. Before each test, the pendulum 39 is deflected to one side as in Fig. 2, and held in this position by a fin 45 on a pillar 44 secured to the sleeve 12, the fin 45 engaging a plate 46 on the arm 40 of the pendulum 39. The scriber 38 bears against a chart 37 secured to the sleeve 12. Operation of apparatus.-In use the lever 13 is first operated in a downward direction to cause the sleeve 12 to move up the column 10 and cause the spring 24 and the shock absorber 33 to be compressed. During this operation the scriber draws a line 61, Fig. 4, on the chart 37. Further downward movement of the lever 13 causes the fin 45 to move upwardly in sliding engagement with the plate 46 and eventually to disengage therefrom immediately before the end 17 of the lever 13 disengages from the part 18 on the sleeve 12. During this period a line 62 is drawn on the chart 37. Immediately after the pendulum 39 commences to swing, the disengagement of the parts 17 and 18 allows the loaded spring 24 to recoil against the action of the shock absorber 33 carried by the sleeve 12. The effect of the shock absorber is indicated by the line 63. The pendu'um is then reset to its displaced position as in Fig. 2 and the lever 13 adjusted about the axis of the column 10 on a mounting 16 in such a manner that the end 17 of the lever 13 again engages in the correspondingly shaped part 18. The lever 13 is then moved in an upward direction to test the shock absorber 33 in the reverse direction. This test results in lines such as 64, 65 and 66 on the chart 37. According to a modification the lever 13 is replaced by a wheel and cam arrangement moving the sleeve 12 against the springs 24 and 25 and for suddenly releasing the sleeve 12 to the opposing force of the springs and the restraining action of the shock absorber.