GB922071A - Improvements in or relating to exciter units for vibratory members - Google Patents

Abstract

922,071. Vibratory mechanism. ROSE BROS. (GAINSBOROUGH) Ltd. Aug. 28, 1959 [May 30, 1958], No. 17267/58. Class 80 (4). In an exciter unit for attachment to a gyratory vibrating member, two out of balance mass systems are driven through differential gear at the same angular speed and in the same sense about a common axis, and the differential gear can be adjusted for altering the angular phasing and hence the out of balance of the mass systems whilst the exciter is operating. The unit comprises an out of balance mass 24 integral with a hollow shaft 23 that is driven through gears 26, 27, a flexible shaft 28 and gears 29 from a motor-driven shaft 35, and a pair of out of balance masses 39 of equal moment to the mass 24 freely rotatable about the shaft 23 and having internal teeth 41 meshing pinions 42 mounted on a shaft 43 journalled in the mass 24 and driven by teeth 53 on the shaft 44, coaxial with shaft 23, and driven by gears 46, 47, flexible shaft 48 and a gear 49 'from a member 51 freely rotatable about the shaft 35 and driven therefrom by the differential gear 33, the gearing being arranged so that both mass systems rotate at the same speeds and the stationary planet carrier of the differential gear 34 being turned through a worm and wheel 37 by a hand wheel 38 for altering the phasing of the mass systems. In Fig. 2, not shown, a work-table, to which is attached a member such as an instrument to be tested under vibration, is mounted on blade springs for vibration in one direction on an intermediate member mounted on blade springs for vibration in a direction perpendicular to that of the work-table and in a plane parallel thereto and the support therefor is mounted on springs for vibration perpendicular to the plane of the work-table. The exciter unit is mounted in horizontal bearings in the support, so that the vibrations of the work-table may be in any plane between the horizontal and vertical.