Patent GB-331357-A (GB)
Title: Improvements in or relating to disc talking machines
IPC: G11B19/265
Filed: 1929-06-08
Abstract: 331,357. Parkes, S. June 8, 1929. Driving. - The speed of rotation of the turntable is varied to keep the linear speed of the sound trace constant, by a friction driving wheel movable across the underside of the turntable, and means are associated with the tone-arm whereby the friction wheel is maintained out of engagement with the turntable when the stylus is in its raised position, manually actuating means being also provided whereby the friction wheel is or may be operatively engaged with the turntable, the driving motor, and the pivotal support column of the tone-arm when the stylus is in its lowered position. As shown, the turntable 4 is loosely mounted on a driving spindle 6 driven through gears 8, 9, by a spring or electric motor 7. A bevel wheel 11 slidably mounted upon and splined to the spindle 6 gears with a bevel wheel 12 loosely mounted in a box 14 housing both bevel wheels. The friction wheel 16 is pinned to a member 17 loosely mounted on a stationary shaft 15, fixed pinions 22 and loose discs 19 being mounted on the ends of the latter. A spindle 21 passing through the member 17 and loosely mounted in the discs 19 carries pinions 23 gearing with the pinions 22. Fixed to one of the discs 19 is a spindle 20 supporting the bevel wheel 12 and a splined clutch member 42 associated with a clutch member 43 connected to the bevel wheel 12. The box-like member 14 and the parts associated with the spindle 15 are carried by a pair of pillars 24 slidably carried by fixed brackets 25 and connected to arms 29 pivoted on a spindle 30. The friction wheel 16 is moved across the underside of the turntable by an arm 38 carrying rollers 41 engaging the sides of the wheel 16, and which may be clutched to the pivotal column 2 of the tone-arm 1. The arm 38 is loosely supported between two flanges 39 on the column 2 and carries a spring catch 40 engagable with one of the flanges 39. The sides of the wheel 16 are also engaged by rollers 56, 56<a> carried on a frame 55 secured to the member 17 and resting on a stationary plate 26. A collar 36 slidable within the column 2 is connected to the tone-arm by a crank arm 37, so that when the tone-arm is raised the collar 36 moves downwards and this movement is communicated by a bell crank 34 to move the arm 33 against a lever 32 on the spindle 30, so that the arm 29 slides the pillars 24 and moves the friction wheel away from the turntable. Engagement between the friction wheel and the turntable cannot be made until the tone-arm is lowered. In operation, the discs 19 are driven by the spindle 6 so that the spindle 21 revolves about its own axis and about the spindle 15 to drive the friction wheel 16. When the tone-arm is lowered, the rod 33 moves out of engagement with the lever 32. A handle 44 is then turned to operate members 45, 51, 51a, and 29 to engage the friction wheel 16 with the turntable, and at the same time members 51, 52, 54 allow the catch 40 to lock the arm 38 to the column 2. At the same time also, a lever 46 associated with the rod 45 disconnects a clutch 49 connecting the turntable directly with the spindle 6 and interconnects the clutch parts 42, 43. When the record has been played, the raising of the tonearm 1 causes the parts to return into the position they occupied before the handle 44 was operated, and after the stylus has been replaced on the record it is necessary again to operate the handle 44 to reset the parts. In a modification, the rod 21 may be omitted, the friction wheel being slidable upon the shaft 15 which is made rotatable. In another modification, the friction wheel may be carried in a vertically adjustable fork carried upon an arm associated with the column 2. When large records are being played. the turntable is also driven by a friction wheel driven by a small variable-speed electric motor, the friction wheel being disengaged from the underside of the turntable simultaneously with the friction wheel 16.