Patent GB-483300-A (GB)
Title: Improvements relating to means for the arrestment of moving parts of conveying or hoisting apparatus in determined positions
IPC: B66B1/36
Filed: 1936-07-10
Abstract: 483,300. Control of two motors. CLAYTON, M. G. July 10, 1936, Nos. 16176/36 and 21996/37. 38 (iii)] Travelling to predetermined limits.-In conveying and hoisting apparatus having a traveller moved by a motor carried thereon along a track the traveller is stopped at predetermined positions by means of current conducting elements associated with the track and disposed at the predetermined positions, and co-operating conducting elements on the traveller, the two sets of conducting elements controlling the circuit of the driving motor to stop the traveller at the predetermined position, and if the position is overrun to reverse the driving motor until the predetermined position is attained. The traveller is driven along the track by a motor f and up an incline by a motor k, and the reversing contactors g, h of the motor f are controlled by conductors a, b positioned along the track at the stopping positions. When a stopping point is approached, a controller e is returned to its off position and the shoes c, d co-operate with the conductors a, b to control the reversing contactors g, h. The incline motor k is under the control of a controller n<2> and drives the traveller up the incline by means of a toothed wheel engaging a rack and the reversing contactors m, n of the motor k are controlled by a switching device so that the toothed wheel is brought into correct relationship with the beginning of the rack as the hoist approaches the incline. The switching device comprises a fixed contact brush l<9> engaging spaced contact segments l<2>, l<3>, l<4> operated by a shaft driven by the motor k and carrying slip rings l<5>, l<6>, l<7>, the connections from the slip rings l<5>, l<6> control the reversing contactors m, n, so that the motor is stopped, reversed, and started until the correct position is reached as indicated by a lamp l<8> supplied from the slip ring l<7> connected with the centre contact segment l<4>. When the motor k is connected to operate the hoist up the incline, the motor f may also be simultaneously connected to the supply with resistance inserted so that the motor f also assists in the operation. The supply for the motors f, k is taken from conductors i<1>, i<2>, i<3> by shoes j<1>, j<2>, j<3>, and the stopping of the motor f to position the hoist may be effected by shoes co-operating with conductors interrupted at the point corresponding to the desired position as described with reference to Fig. 1 (Prov.) (not shown). The conductors a, b may be disposed at different distances from the track so as to co-operate with their respective shoes c, d. Three limit switches o, p, q are operated from the track, the first o rendering the controller e of the motor f ineffective for normal operation, the second p rendering the tooth positioning gear inoperative, and the third q cutting off all current from the controller e. When the limit switch o has operated a switch r may be operated to give slow movement of the traveller. Where the traveller has a wide span the contact disc and slip rings controlling the motor 7c are duplicated, and the shaft on which they are mounted is in two parts coupled by a clutch. A modification of the tooth positioning control gear is described briefly with reference to Fig. 3 (Prov.) (not shown). In Fig. 2 (Prov.) (not shown), an arrangement for bringing the traveller to rest is shown in which stopping collectors make contact at the stopping position,