GB395083A - Improvements in means for regulating the relative speeds of the picture and sound apparatus of a talking-picture installation - Google Patents

Abstract

395,083. Maintaining defined speeds of motors. NAAMLOOZE VENNOOTSCHAP PHILIPS' GLOEILAMPENFABRIEKEN, 13D, Emmasingel, Eindhoven, Holland. March 7, 1932, No. 6803. Convention date, March 6, 1931. [Class 38 (iii).] In a means for maintaining synchronism between the sound and picture apparatus of a talking picture installation, a single electric motor is employed for driving the shafts both for the sound and the picture apparatus, the shaft for the sound apparatus being kept at constant speed by a centrifugal brake. Fig. 3 shows an arrangement wherein a motor 35 drives a shaft 40 for the picture projector which is coupled by a differential gear 41 to the shaft 42 driving the turntable 39 and kept at constant speed by a centrifugal brake 46. A contact 59 is oscillated by an eccentric 57 and the co-operating contact 56a is in the form of a cam and is connected to the planet wheel 49 so that deviation from synchronism between the shafts 40, 42 varies the period of make and break which controls the insertion of a resistance in the motor circuit to maintain synchronism. In a modification, the differential coupling is replaced by a band driving both shafts 40, 42 with a jockey pulley mounted in a loop between the shafts. The jockey pulley is mounted upon a pivoted lever and also carries an eccentric for actuating the contact 59. Variations in the length of the loop vary the limits of movement of the contact 59 which co-operate with an elastically mounted contact. In a further modification, the eccentric driving the contact 59 is moved longitudinally, this movement being employed to vary the period of make and break. Fig. 1 shows the two shafts 1, 2 provided with cams 2, 3, actuating rods 6, 20 pivoted at 8, 22 to levers carrying contacts 9, 11 and 24, 25. The contacts may be connected in series or parallel and control the period of insertion of the resistance 31 in the motor circuit. Specifications 343,811 and 347,026 are referred to. The Specification as open to inspection under Sect. 91 comprises also a construction as set out in Fig. 8 (Cancelled) wherein a combined sound and picture film 131 is unwound from a reel 133 and wound upon the reel 135. The film is driven by rollers 132, 134 connected to a single motor and also by a maltese cross arrangement 136 controlling movement past the lens 137. The rolls 140, 141 are kept at constant speed by a centrifugal brake 148, the shaft 145 also oscillating a contact 167 by means of an eccentric 165. A spring loaded roller 156 is arranged in the loop 157 of the film and varies the position of the contact 164 to vary the period of insertion of a resistance in the circuit of the motor driving the rollers 132, 133, 134. This subject-matter does not appear in the Specification as accepted.