Patent GB-561559-A (GB)
Title: Improvements in or relating to devices for controlling the forward movement of a stylus carriage of a machine for recording sounds on discs
IPC: G11B19/20
Filed: 1942-11-19
Abstract: 561,559. Gramophones; change speed gearing. FONTANA, C. Nov. 19, 1942, No. 16353. [Class 40 (ii)] [Also in Group XXIV] A device for controlling the feed of a stylus carriage in sound recording on a disc comprises two freewheel devices 26, 38, Fig. 1, one 26, driven through a speed gear-box for producing the regular spiral groove during recording, and the other, 38, driven through a clutch to produce quicker pitched spiral grooves between items of recording and at the end of the recording, which last quick-spiral is followed by a circular groove. As shown, the two freewheel devices 26, 38 drive a shaft 23 connected to the feed mechanism of the stylus carriage. The freewheel device 26 is driven by pins 24 to shockabsorbing blocks 25 of plastic material in recesses in a pinion 19. The pinion 19 and three others 20, 21, 22 are fastened together and loosely mounted around the shaft 23. These pinions are in mesh with pinions 11, 12, 13, 14 separately mounted loosely on a hollow shaft 4 to which is keyed a pinion 3 in mesh with a pinion 2 on a shaft 1 driven by gearing from and at the same speed as the turntable. A key 6 in the hollow shaft 4 is attached to a rack 8 adjustable by a pinion 7 on the shaft 9 of a hand wheel. The key 6 slides along a slot 10 in the hollow shaft to engage one of the slots 15, 16, 17, 18 of the pinions 11, 12, 13, 14 to adjust the speed of the gear-box according to the setting of the hand wheel shaft 9 for the desired pitch of the recording groove. The shaft 1 carries also a pinion 30 by which it drives a countershaft 32, Fig. 6, through a pinion 31. The countershaft 32 carries an electromagnetic clutch 33 by which it can transmit rotation to a pinion 34 in mesh with pinions 36, Fig. 7, and 35, Figs. 1 and 6. The pinion 36 drives a bank of contact discs M, L, K, I, H; and the pinion 35 drives the freewheel device 38 through a shock-absorbing connection 37. To perform the several desired operations, the electromagnetic clutch 33 is controlled by push-buttons and the contact rings M, L, K, I, H in conjunction with relays, switches, and electromagnetically operated devices for putting the feed-nut in operation and for lowering the stylus to operative position. When the operation is to be started a switch T, Fig. 8, is closed by hand, an electromagnet E puts the feed-nut in action and holds the switch T closed ; another switch U is then closed by hand to energize an electromagnet D which lowers the stylus to operative position and holds. the switch U closed. The stylus then produces the normal recording spiral groove. When it is desired to produce a quick spiral at the end of a recorded item before the next item, a push-button switch S is closed, thereby energizing the electromagnetic clutch 33 which after one revolution of the turntable is again de-energized by the control of the contact rings H, I, K, L, M in conjunction with the relays A, B, C. A second quick spiral may be made to follow by the closing of a push-button switch R just before the revolution is completed. At the end of recording, a push-button switch F is closed and causes the production of a quick spiral followed by a circular groove after which the electromagnets D, E are switched off, the stylus raised and the feed stopped. If the push-button switch F is not closed by neglect, then at the end of the travel of the stylus carriage, this carriage will automatically open a switch P which cause electromagnets E, D to be deenergized, the feed will be stopped and the stylus raised. At any time during the run, the stylus may be raised by the opening of a push-button switch G, or the stylus may be raised and the feed at the same time stopped by the opening of the push-button switch V.