Patent GB-190815111-A (GB)
Title: Improvements in Apparatus for Raising and Lowering Stage Scenery and the like.
Filed: 1908-07-16
Granted: 1909-06-03
Abstract: 15,111. Crompton & Co., and Williams, A. July 16. Theatrical appliances.-The suspension ropes a of theatre curtains &c. b are passed over a series of independent winding-drums, each of which is driven from a disk, adapted to be put into driving connexion with either of two disks or arms rotated in opposite directions by gearing and an electric motor provided with a slipping clutch. The motor l drives through gearing m, n, o, p, q, r a shaft k carrying fixed driving-arms 8, and loose disks 7, which are rotated on the shaft in an opposite direction by gearing t, z, 3, 5. Between the disks 7 and arms 8 are toothed disks i, which are mounted loosely on the shaft k and drive by chain gearing the winding-drums e. Each disk i is provided with a screwed lug 10 and a fixed lug 9, the screwed lug being adjustable on the disk by providing the latter with a number of tapped holes 24. The disk 7 and arm 8 have recessed lugs 12, 11, adapted to engage with the lugs 9, 10 respectively, and corresponding lugs are brought alternately into engagement to drive the disk i in one direction or the other by parallel levers, which are connected by a bar 13 and are provided with lugs 14, 15, engaging in grooved collars on the disk 7 and arm 8 respectively. When the parallel levers are in a central position, the disk i is free from engagement with the driving-lugs, and the scenery can be operated by hand. The shaft k makes a complete revolution for a complete rise or fall of a curtain, and by adjusting the position of the lugs 10 on the disks i the requisite travel of the scenery is determined. The following means are provided to cause an automatic stopping of the motor when the scenery has reached its pre-determined position. Loosely mounted on the shaft k, and connected to the wheel r by means of a spring u, is an arm t, which can abut against a stop w on a spring-returned hand-operated lever x, and can be pressed by a stop s on the wheel r against a spring buffer v to stop the wheel r from rotating, and to make an electric connexion which shortcircuits the no-voltage coil of the motor starter and thereby breaks the motor circuit. In operation, the lugs 10 are positioned, the lever x is depressed by the operator to allow the arm t to pass the stop w, and the motor starter is operated. The curtains are operated as above-described, and as soon as the wheel r makes a complete revolution, the arm t comes in contact with the stop w and the stop s comes in contact with the arm t, thereby causing the above operations. The slipping clutch, which allows the motor to rotate after the gearing has been stopped in the above-described manner, consists essentially of two series of spring-pressed friction disks, the members of one series being arranged alternately with the members of the other series. A magnetic brake for the motor is brought into operation when the motor-starter handle is brought into the off position as above-described. The brake consists of bands 19 normally drawn together by a spring, but pressed apart by a lever rotated about its centre by an arm 20 pivoted to the core 21 of an electro-magnet 22.