Patent GB-807436-A (GB)
Title: Magnetic sound recording and reproducing apparatus
Inventor: MILTON ARTHUR JOHN
IPC: G11B15/43
Filed: 1954-04-20
Abstract: 807,436. Magnetic sound recording and reproducing apparatus. WALTER INSTRUMENTS Ltd. April 20, 1955 [April 20, 1954], No. 11392/54. Class 40 (2). A magnetic sound recording and reproducing apparatus which utilizes a resilient wire or tape 13 stored on reels 10, 11 comprises a control lever 46 and a capstan presser roller lever 38 both pivotally mounted at one end on a base-plate 12 and arranged in superimposed relationship with their free ends extending in opposite directions, the two levers being interconnected by resilient means which pivots lever 38 to cause a capstan presser roller 43 rotatably mounted at the free end thereof to engage the tape 13 against a capstan 17 when the control lever 46 is pivoted into an operative position in which pressing means mounted at the free end thereof engages the tape against a guide or guides. As shown, the levers are respectively pivoted on spindles 39, 47 secured to base-plate 12; the interconnection comprises a spring steel strip 53 engaging an adjustable setting screw 52 carried in an upstanding lug 51 of lever 46, together with a tension spring 61 which anchored between a lug 62 on the base-plate and a lug 49 of lever 46 biases the levers to their inoperative forwardmost positions the lug 49 engaging an arcuate portion 50 of lever 38. The pressing means comprises one or a pair of arms 55 carrying felt pads 57, 58 respectively engageable with the waist 14<SP>1</SP> of a tape guide post 14 and the non-magnetic gap of a transducer head 16. Lever 46 also has a lug 59 carrying a roller 60 which holds the tape 13 clear of the transducer head 16 when the apparatus is in its inoperative condition, and on its underside the lever carries a downwardly projecting pin 63 which projects through a base-plate clearance slot 64 into a V-shaped cam slot 65 in a laterally slidable control plate 19. A control lever 21 is pivotable about a bracket 23 fixed to the baseplate and determines by location in the shoulders 27 of apertures 22 in the base-plate the operative condition of the apparatus. Movement of lever 21 from the central position shown to the left or to the right, to record or play back respectively, causes camslot 65 to move both levers 38, 46 into their operative positions with roller 43 and pads 57, 58 engaging the tape 13 and roller 60 clear of the tape. The latter is then driven at constant speed from an electric motor, not shown, by the capstan 17 which has a flywheel 36. Between post 14 and transducer 16 is an erasing head 15 which comprises, Fig. 6, a permanent magnet 28 located between the flanges of a magnetic member 29 whose operative tape contacting surface 34 has a diagonal slit 35 and which is secured to an arm 30 pivoted on the post 14 and having a downwardly projecting pin 31 which extends through a base-plate clearance slot 32 to engage another cam slot 33 in the control plate 19; when control lever 21 is set to the recording position erase head 15 is pivoted to engage the tape 13. The take-off and rewind reels 10, 11 are mounted on spindles driven as described in Specifications 807,435 and 807,437, which spindles have fixed thereto brake discs 66, 67 engaged by brake pads 69, 70 on a transverse arm 68 secured to a slidably mounted plate 71 which is biased by a tension spring 72 to a rearwards, brake-engaging position and has an upstanding lug 73 engaging in the inoperative condition of the apparatus a V-shaped notch 74 in the control plate 19 so proportioned that in all operative positions of control lever 21 the brakes are withdrawn from the discs 66, 67.