GB1465327A - Control fo reversible vibratory equipment - Google Patents

Abstract

1465327 Controlling vibrations by tuning absorbers REXNORD Inc 30 May 1974 [2 July 1973] 24005/74 Heading F2X A resiliently mounted vibratory equipment, e.g. a vibratory conveyer, driven by rotating eccentric weights is provided with at least two sets of tunable dynamic vibration absorbers that may be selectively tuned to either oppose or aid the eccentric weights in producing vibration of the equipment along either of a pair of axes. A conveyer that may be vibrated to convey material in either direction so as to either discharge or level the material comprises a container or trough constituting a work member 1 resiliently supported for vibration on air springs 2. The work member 1 is vibrated by eccentric weights 3 mounted on a shaft 4 belt driven from a motor 5. The direction and amplitude of vibration of the work member 1 are controlled by four tunable dynamic vibration absorbers 6, 7, 8 and 9. Each absorber comprises a vibrating weight 10 guided by rocker arms 11, its motion being controlled by a pair of air springs 12, the spring rate of which is dependent on the inflation pressure. Absorbers 6, 9 form a pair adapted to vibrate along a path inclined upwardly toward the left while absorbers 7, 8 form a second pair adapted to vibrate along a path inclined upwardly toward the right. If one pair, such as 6, 9 are tuned so that the weights 10 in combination with the springs 12 are resonant at the operating speed of the eccentric weights 3, they vibrate at such amplitude and phase as to practically counterbalance the force of the eccentric weights 3 in the direction of vibration of the weights 10 and there is thus little or no vibration of the work member 1 in this direction. At the same time, the other pair 7, 8 may be tuned so that work member 1 and the weights 10 of these absorbers, together with the co-operating air springs 12, form a twomass vibratory system resonant near and preferably just below the operating speed. With this tuning the weights 10 of the absorbers 7, 8 vibrate in phase with the eccentric weights 3 to increase the vibration of the work member 1 along the path of vibration of these weights 10. By varying the tuning the amount of this reinforcement may be varied. It is possible to select both the direction and the amplitude of vibration by inflating the several air springs 12 to the proper pressures and control equipment for this purpose is illustrated in the lower portion of Fig. 1.