Patent GB-821710-A (GB)
Title: Magnetic sound recording device
IPC: G11B27/34
Filed: 1956-09-26
Abstract: 821,710. Magnetic recording and reproducing apparatus. LOEWE, S. Sept. 26, 1956 [Sept. 28, 1955], No. 29333/56. Class 40 (2). A magnetic tape recorder in which the tape may be run in reverse as desired and provided with erasure means, has a single control lever for the various operations, which lever is connected to an indicator device giving the position of the tape at any time, whereby any part of a recording may be located for erasure. The tape 6, Fig. 1, from reels 23, 24 lying on friction discs 25, 26, is taken past rollers driving indicators 36 37 and is driven by means of pulleys 7, 8 connected by friction gearing to a motor 9. A swivel device comprising a holder 18 carrying pressure rollers 16, 17 is used to press the tape against the appropriate pulley 7, 8 according to the desired running direction. The holder 18 has a tongue 19 extending between electromagnets 21, 22 and biased to the inoperative position by springs 20. On energizing the electromagnets, one of the rollers is moved against the tape. Electromagnets 29, 30 below the friction discs 25, 26 are energized when it is necessary to increase the friction between the disc and its associated drive disc (not shown) to obtain high-speed running. A braking shoe 31 is pulled into contact with the friction discs by a spring 32 when an electromagnet 33 is deenergized. Contact-springs 34, 35 automatically stop the drive when the respective reel 23, 24 has been wound off. A control lever 1 is used to operate the recorder as described in Specification 22330/56, a button 3 being used to set the tape in high-speed reverse motion. An electromagnet 4, 5 effects electrical release of the lever 1. The indicator 37 may be arranged as in Fig. 4 with a dial arranged to show continuous readings for the first and second tracks on the tape, so that if the first track is 100 m. the dial gives readings up to 200. To do this, the pointer is driven in the same direction for both forward and reverse motion of the tape. The moving tape 53 rotates a roller 54 fixed on a spindle carrying a friction disc 55 which drives a disc 56 to rotate the pointer spindle 52 by means of disc 59, the disc 56 being moved into driving contact by means of an electromagnet 60. When the tape is reversed, the electromagnet 62 moves a lever 61 carrying the discs 55, 56, 57, 58 so that the drive to disc 59 is through discs 55, 57, 58, and therefore disc 59 rotates in the same sense as before. By setting an electric contact carrier 63, the tape can be stopped at any desired position, a circuit to stop the tape being closed when a contact 65 carried by the pointer touches a contact 64 on the carrier. In the embodiment of Fig. 5, spring means 75 returns the pointer to the zero position and the pointer is driven through reduction gears 77, 78, 79, 80 and a friction coupling 81, 82. A spring 83 holds disc 81 in contact with disc 82. By means of a handle 84 or electromagnet 85, lever 86 can be pivoted to pull down the disc 81 and so free the pointer. If the pointer alone is returned to zero it impinges on a spring 69 which prevents the contacts 70, 71 from closing. If the pointer is returned by the reverse motion of the tape, the pressure of the pointer is strong enough to bend the spring, so that the contacts close. In a modification the indicator has an outer scale corresponding to the first track on the tape and. an inner scale with the markings in reverse for the second track, so that the movement of the pointer corresponds to both movements of the tape. The scale in use at any time may be illuminated to facilitate recognition. The indicator may also be in the form of an endless tape or cylinder.