US2938730A - Gramophone record changers - Google Patents

Description

May 31, 1960 H. v. 'SLADE GRAMOPHONE; RECORD CHANGERS 2 Sheets-Sheet 1 Filed Dec, 2 1953 May 3], 1960 H. v. SLADE GRAMOPHONE RECORD CHANGERS 2 Sheets-Sheet 2 Filed Dec. 2, 1953 I Ill/till Patented May 31,19

2,938,730 GRAMOPHONE RECORD CHANGERS Hector Vaughan Slade, Swindon, The Garrard Engineering and pany Limited, Swindon, England England, assignor to Manufacturin Com- This invention relates to gramophone record changing mechanism which incorporates a rotary control unit by which the various phases in the record changing cycle are controlled and etfected.

Hitherto the rotary control unit has been driven either by the spindle which supports the turntable or by an inner edge of the rim of the turntable.

When using records which require speeds of 33%, 45 or 78 r.p.m. this results in changing cycles which vary in length as the time cycle is in direct proportion to the revolutions of the turntable.

The object of the present invention is to provide an improved mode of driving the rotary control unit whereby the time cycle is substantially uniform whatever the speed of turntable is required.

According to the invention, the rotary control unit of a gramophone record changer is driven from the motor spindle, means being provided for initiating the drive at the commencement of the cycle and cutting out the drive at the end of the cycle.

A gear train meshing with a gear of the control unit may be displaceably mounted whereby a pulley or wheel thereof may be moved into and out of driving contact with the motor spindle or a pulley thereon.

In the accompanying drawings:

Figure 1 is a plan of the improved drive with the parts in their inoperative position; and

Figure 2 is a partial elevation.

In carrying the invention into etiect according to one convenient mode by way of example, the rotary control unit of a record changing mechanism comprises a rotary member 1 having appropriate cam means 20 by which the various phases of the cycle including raising of the pick up and swinging the arm outwardly, releasing a record from the bottom of the stack for delivery to the turntable, returning the arm and lowering the stylus on to the record, are effected in known manner.

The control unit 1 is provided with a driving gearwheel 2 and meshing with said gearwheel is a gear 3 of a gear train 4 mounted upon a plate 5 which may pivot about the axis of said gear 3.

The gear train 4 has an end unit comprising a rubber tyred wheel 6 which is adapted when the mounting plate 5 is displaced from its normal position to engage the spindle 21 of the motor 22 or a pulley 7 thereon. In order to provide the necessary driving pressure a spring 8 biases the mounting plate 5 into the operative driving position of the wheel 6.

The mounting plate 5 is held in its normal inoperative position by the engagement of a portion 9 of the plate 5 with a locking pin 10 on the gear wheel 2 of the con- 2 trol unit 1, said portion 9 being recessed at 11 to accommodate the pin and being held in engagement therewith by the biasing spring 8.

The control unit 1 is also provided with a second pin 12 by which a starting impulse may be imparted to the control unit 1 to cause disengagement of the locking pin 10 and the mounting plate recess 11 and then allow the biasing spring 8 to pivot the plate 5 and bring the rubber tyred pulley 6 of the gear train 4 into driving engagement with the motor spindle pulley 7.

The starting impulse is imparted to the control unit 1 by a pivoted spring biased impulse lever 13 which has an impulse surface 14 normally engaging the impulse pin 12 and which lever when released imparts a thrust to the impulse pin 12.

The impulse lever 13 has an arm 15 adapted to be engaged by a detent 16 on a pivoted trip lever 17, the movement of which to its release position as eflected in known manner when the stylus reaches the end of the record and passes into the run out groove.

The mounting plate 5 is supported by a fitting which carries the control unit 1 and which is supported by the motor plate 24.

The impulse lever 13 and the trip lever 17 are pivotally mounted on a plate 25 supported by the motor plate 24.

In operation when the impulse lever 13 is released it moves to the position shown by dotted lines a imparting a slight rotation to the control unit 1 suflicient to move the locking pin 10 out of its recess 11 so that the spring 8 pivots the plate 5 and brings the pulley 6 into engagement with the pulley 7 whereby the motor 22 will drive the control unit 1 through the train of gears 4.

When the impulse pin 12 is approaching the end of its cycle, i.e. one revolution, it engages a cam surface 18 on the impulse lever 13, pivoting such lever so that its arm 15 moves beyond the detent 16 in the trip lever to the position shown by dotted lines b. On the impulse pin leaving the cam surface it comes into engagement with the impulse surface 14 so that the biasing spring 19 of the impulse lever moves the arm 15 backward into engagement with the detent 16 of the trip lever 17 (full line position).

This rearward movement of the impulse lever 13 causes a slight rotation of the control unit 1 suflicient to move the locking pin 10 to a position to engage with the recess 11 on the mounting. Just prior to such movement the locking pin 10-has engaged a cam surface 26 on the mounting plate 5 and the movement of the control unit 1 will thus cause a displacement of the mounting plate 5 to break-the drive between the motor 22 and the gear wheel 2 of the control unit 1.

I claim:

1. In a record changer having a multiple speed record pick-up arm, a rotary control unit for the record changing cycle and a constant speed motor having a driving spindle, driving means for operating said unit at a substantially uniform speed independent of the turntable speed comprising, in combination, a first gear fixed to rotate with said unit; a second gear continuously engaging said first gear and forming part of a gear train having a rotatable driving element; a plate carrying said gear train and pivoted about the axis of said second gear, said plate being swingable to a driving position in which said driving element is in driving engagement with said driving spindle; means biasing said plate to a position disengaging said driving element from said spindle; and' References Cited in the file'of this patent UNITEDWSTATES PATENTS Stephenson Aug. 15, Compare Mar. 13, Roe June 10, Alexandersson et a1. Sept. 30, Ballentine eteal. Aug. 30, Zandelin et a1. Oct. 11,

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