Patent GB-1216845-A (GB)
Title: Improvements in and relating to record players
Inventor: CHEESEBORO ROBERT GAINES
IPC: G11B19/20
Filed: 1967-12-08
Abstract: 1,216,845. Record player. CHEESEBORO PRODUCTS CORP. 8 Dec., 1967 [12 Dec., 1966], No. 55906/67. Heading G5R. In a portable gramophone for playing single 7 inch records which can be operated in any attitude, insertion of a record through an entry aperture in one side of the gramophone energizes a turntable drive motor which initially acts to move the turntable with the record thereon into contact with a record clamping device and a playback head; on completion of play the drive motor is switched to reverse to release the record by moving the turntable and record away from the clamping device. The gramophone plays records with a small or large centre hole. Record engagement, drive and release.-On entry the record is partially positioned by brackets 209 supporting the power supply rechargeable batteries 77 and actuates a forward/ reverse drive switch to its forward position and a power supply microswitch 91 to its " on " position. Motor 66 then operates to turn drive wheel 37 clockwise. The turntable 35 which is threaded on the hub of the drive wheel 37 is engaged and held against rotation by a rubber grommet 96 mounted on a pivoted arm 92 which supports the on/off switch 91, so that the initial drive moves the turntable axially into contact with clamp disc 45 which is spring- mounted and clutch coupled to its support member 46 to allow clockwise rotation only. As the turntable is raised switch support arm 92 is moved anticlockwise by spring 94 until stop screw 94 engages the chassis and the turntable moves out of engagement with the grommet. Movement of the arm moves a finger 99 into contact with switch-operating spring 97 to hold the switch in its " on " position and also moves via finger 101 the playback head return lever 89 to the position shown in Fig. 2. In its raised position the record moves into contact with stylus 80 of the pick-up head 84 and the record is played. Towards the end of record play the head engages return lever 89 and rotates it and its mounting shaft 90 ina clockwise direction and as the head enters the record run-out groove the movement is sufficient to overcome the bias of a toggle spring which actuates the forward/reverse switch to reverse the direction of rotation of the motor causing the turntable to lower and release the record. This movement rotates the switch support arm 92 clockwise about its pivot 93 and this movement via arm 101 causes a counter clockwise rotation of shaft 90 which moves the pick-up head by means of arm 98 to its outer position. In addition, the movement of the switch support arm moves finger 99 out of contact with spring 97 so that switch 91 moves to its " off " position-deenergizing the motor. Pick-up head 84 includes cartridge 79 which is mounted by means of a spring member 84 in a wheeled carriage 83 which runs on rails 82 extending radially of the turntable. The rails are facing U-shaped members which permit no vertical movement of the head and hence allow record play in any attitude of the player. Motor 66 has a printed circuit rotor 67 and an annular magnet stator 70. The motor is governed from a servo control 78 including an R.C. oscillator pulse source, each pulse supplied to the magnet from the oscillator having a duration determined by a photo-cell arrangement 177, 178 which monitors the motor speed by responding to light reflection from the printed circuit conductors. The motor can operate to provide turntable speeds of 33<SP>1</SP>/ 3  and 45 r.p.m. the circuit being switched 179 and provided with speed-adjusting potentiometers 180, 181. Playback system is provided with a stereophonic head and amplifier which work in a monophonic mode with speaker 107 until a second speaker is jacked into the unit. This operates switching means which automatically change the system to the stereophonic mode. Tone and volume controls are provided. Power supplies are six batteries which can be recharged either from the mains via a voltage dropping cord or from a D.C. source, e.g. a vehicle battery. Gramophone case is provided with a U-shaped handle 32 mounted on a pair of spring-loaded pivots whereby the handle may be moved through 90 degrees to support the case with its speaker directed downwards on to, e.g. a table which acts as a sounding board. Support leg chambers 157 are provided for storing pairs of legs 33, 34 for supporting the case vertically. A second case containing the second loudspeaker for stereo operation and a record store may be clipped on to the main case 20.