GB544760A - Improvements in and relating to apparatus for recording and reproducing sound - Google Patents

Abstract

544,760. Sound recording and reproducing apparatus. W.A.F. CO., Ltd., and ALLEN, H. H. Feb. 28, 1941, Nos. 2746 and 4531. [Class 40 (ii)] In an apparatus for mechanically recording sound on films, the recording head 6 is so mounted that it cannot move towards or away from the film 1 but only transversely thereto, whereas the film bears at the recording point against a cam 4 which can be turned to adjust the depth of cut, and the recording head is automatically traversed across the film during the travel of the film. As shown, the cam 4 is a circular segment mounted slightly eccentric-' ally on a shaft 8 which can be turned by a handle 13 to various positions indicated by a pointer 14 on a dial 15. When the circular segment faces the recording head, the stylus 12 is in contact with the film and the depth' of cut can be regulated by the rotational setting of the segment. When the segment is turned away from the recording head, space is left to permit removal and insertion of stylus which abuts against a stop in the recording head to ensure correct position. The recording head is mounted on and guided by a rod 10 and lead screw 11. The film 1 is an endless one with a twist permitting recording on opposite sides alternately in a number of parallel or slightly oblique tracks in continuation one of another. The film passes through a gate 3 to the cam 4 and thence upwards to a driving sprocket over which is situated a reproducing head 7. The sprocket 5 is driven through suitable gearing by a motor 16 which also serves to drive the lead screw 11 through reducing gear 17, change speed box 18, and clutch 19. The change speed box enables the pitch of the tracks on the film to be varied or compensation to be made for different lengths of film. The traverse of the recording head is indicated by a dial 21 geared to the screw 11 and movable behind a window 22 in the panel 2. The gate 3 is provided with two pairs of contact rollers 25, 26, to co-operate with contacts on the film to determine two stopping positions of the film, one for recording and one for reproducing. Various operations of the apparatus are controlled by the rotational setting of the shaft 8 by the handle 13. Normally when the apparatus is out of action, the shaft is set with its pointer 14 at the point " Off " on the dial 15, Fig. 6. To start recording, the pointer is turned to "Stop Record"; this causes the motor to drive the film until the contact on the film automatically stops the drive. The pointer is then turned to " Cut " ; this starts the motor again, but on a circuit independent of the film contact, and also operates the clutch to transmit motion to the lead screw. Finally the pointer is turned to the desired " Cutting Depth " graduation. For reproduction, the pointer is moved from " Off " to " Stop Repro " and then to " Reproduce." Specification 544,764 is referred to.