GB342766A - Improvements in or relating to talking picture apparatus - Google Patents

Abstract

342,766. Belt driving gear. HARRIS, A. W., 76, Brondesbury Villas, Kilburn, London. Nov. 7, 1929, No. 33978. [Class 80 (ii).] A belt 4 is included in the transmission gear between a driving motor 2 and talking picture or like apparatus and means is provided for increasing the distance between the pulleys on which the belt runs, the said means acting in opposition to a retarding device so that the motor takes up its load gradually after it has been started. As shown, the motor 2 is mounted upon a plate 13 pivoted at 14. A plunger 17 of a dashpot 16 is fixed to the plate 13. When the motor is to be started up a pneumatic pump connected to a pipe 18 is operated to lift the plunger 17 and motor 2 rapidly so that the driving belt is slackened. The plate 13 is maintained in the up position by a releasable rest 20 which is moved into the engaging position by a spring-loaded plunger 20a. The motor is then started up, and when it has run up to speed the rest 20 is disengaged from the plate 13 and the dashpot 16 which has a valve 19 permits the plunger 17 to sink slowly so that the belt is gradually tightened, thus allowing the motor 2 to take up the load gradually. In its lowest position the plate 13 rests on an adjustable stop 15. To prevent energization of the motor 2 when the belt 4 is tight the motor circuit has two switches in parallel, one being closed only when the plate 13 is in its highest position and the other being closed only when the motor is running. A brake lever 21 under the action of a spring 26 has a lug 23 engaging a lug 25 on the plate 13 so that when the plate 13 is raised and the motor is running idle the brake 21 engages the pulley 5 and holds it stationary, the brake 21 being released automatically as the plate 13 falls. The driven shaft 6 is connected to a kinematograph projector by a releasable dog clutch 27. The drive from the shaft 6 to the gramophone turntable 1 is transmitted by one or other of two sets of chain and sprocket gearing 8, 8a, the sprocket wheels 7, 7a, being arranged alternately fast and loose on the shaft 6 on the operation of a knob 6a. When the gramophone and kinematograph are working together the sprocket 7 is fast ; if the gramophone is used during the projection of a silent film the wheel 7a is fast. A base 30 carrying the motor 2, dashpot 16, and the brackets 34 of the pivot 14, is supported from the main structure of the machine by bolts 32 surrounded by rubber shock-absorbing sleeves 33. Specifications 336,684, [Class 80 (ii), Gearing, Variable-speed &c.] and 341,170 are referred to.