GB921781A - - Google Patents

Abstract

921,781. Driving apparatus for endless conveyers. GEBR. EICKHOFF MASCHINENFABRIK U. EISENGIESSEREI m.b.H. July 24, 1959, No. 25420/59. Class 78 (1). In an endless conveyer of the belt or articulated plate type which operates on an incline, energy absorbed by a braking mechanism engaging the descending run is transferred to a driving mechanism engaging the ascending run by means arranged to apply a force which changes or tends to change the speed of a member driven by the braking mechanism. In one embodiment, Fig. 1, a driving mechanism 2 comprising an endless driving chain, reduction gear 3 and a three-phase electric motor 4 is positioned with its driving chain in engagement with the ascending run 1 of the conveyer, while a braking mechanism 5 comprising a threephase motor 8 identical with motor 4, reduction gear 7 identical with gear 3, and an endless driving chain is positioned with its driving chain in engagement with the descending run 6 of the conveyer. A gear mechanism 9 is interposed between the motor 8 and reduction gear 7 such mechanism comprising an epicyclic gear, the annulus of which is driven through an infinitely variable speed gear-box 11 from an auxiliary electric motor 10 of relatively low power. The arrangement is such that with the speed of the annulus of the epicyclic gear equal to zero the mechanism 9 provides a 1: 1 ratio between the motor 8 and reduction gear 7 so that motor 7 is driven by the conveyer at its synchronous speed. By adjusting the speed of the annulus through manipulation of gear-box 11, the speed of motor 8 is increased above synchronous speed to an extent depending upon the desired amount of braking of the descending run, this causing the motor 8 to act as a generator feeding power back to the supply and so reducing the power requirements of the system. The gear-box 11 may be driven by a wheel in contact with the conveyer, e.g. the upper run, instead of by auxiliary motor 10 (Fig. 2, not shown). In another embodiment, Fig. 3, a driving mechanism 14 comprising a motor 18, reduction gear 19 and endless driving chain engaging the ascending run 1 is positioned adjacent a braking mechanism 15 comprising a reduction gear 17 identical to gear 19 and an endless driving chain engaging the descending run, and the two mechanisms are mechanically interconnected by a gear mechanism 16 comprising a differential unit of which the cage is driven through an infinitely variable speed gear-box 21 by an auxiliary motor 20 giving a constant torque. By manipulating the gearbox 21 a variable torque is applied to the differential cage which applies a variable braking effect to mechanism 15 and a corresponding variable additional driving effort to the mechanism 14. The mechanism 16 incorporates additional gearing to cause it to have a ratio slightly different from 1 : 1 so that the differential cage rotates at a slow speed to provide for ventilation of motor 20 which rotates at a speed determined by the setting of gear-box 21.