US1815536A - Automatic stop for gramophones - Google Patents

Description

July 21, 1931. W|NKELMANN 1,815,536

AUTOMATIC STOP FOR GRAMOPHONES Filed Nov. 15, 1928 2 Sheets-Sheet 1 /V// 4 III] 72 7% VII! 7 1 irrawfae 6A2 Maw/v.

y 1931-: R. WINKELMANN 1,815,536

AUTOMATIC STOP FQR GRAMOPHONES Filed Nov. 15, 1928 2 Sheets-Sheet 2 0 6 d :lI/IIIIIIIIIIIIII/fl g a Patented July 21, 1931 UNITED STATES PATENT OFFIC AUTOMATIC s'ror ron enanornoivns Application filed November 15, 1928, Serial No. 319,628, and in Great Britain November 16, 1927.

This invention relates to an automatic stop for gramophones whereby the gramophone turntable may be automatically arrested when the reproducing needle reaches the end of the record groove or other predetermined position, and the invention has among its objects to provide a simple and effective construction of stop which may be readily adjusted in accordance with the varying distance from the centre of the record at which the record'groove terminates.

According to the invention a resilient or resiliently mounted member fitted with a brake block or the equivalent for engaging with the under side of the gramophone turntable conveniently adjacent the rim, thereof, is adapted normally to press the brake block or the equivalent upwardly into engagement with the turntable, and a member carried by the tone arm of the gramophone is adapted to co-act with the member carrying the brake block in such manner that during the playing of a record the brake block is depressed by the weight of the tone arm out of engagement with the turntable, the two members being so arranged or provided that, when the reproducing needle reaches the end of the record groove or other predetermined posltion, the member carrying the brake block is permitted to rise into the normal position in which the brake block engages with the turntable to bring the latter to rest. Preferably the members are relatively adjustable, as by providing the member carrying the brake block to be capable of angular adjustment about a fixed pivot so that the initial relative positions of the members and consequently the position at which the stop be- 40 comes operative may be varied. Conveniently, the members are soarranged or'provided that the setting of the members maybe effected by placing the reproducing needle at the position at which the record groove terinmates, the tone arm being then raised vertically so as to disengage the members before carrying it to the starting position.

The member fitted with the brake block may comprise a fiat metal plate or arm mounted preferably upon the top of the motorboard so as to extend substantially radially beneath the turntable and so as to form a spring serving to press the brake block or the equivalent upwardly into engagement with the under side of the turntable or rim., In order to permit the spring plate or arm to be adjusted within limits, it may be fastened to the motorboard by means of a screw or the equivalent at or adjacent its inner end so that it is capable of swinging about the pivot so formed, the angular movement of the plate or arm being restricted by means of fixed stops extending upwardly from the motorboard orrby any other suitable means.

The co-acting member carried by the tone arm may comprise a downwardly extending rod which engages slidably with the flat upper surface of the extending part .of the (plate or member, which latter is provided with a hole or recess in a determined position for the reception of'the downwardly extending rod so as to permit the member carrying the brake block to rise, for the purpose described. The plate or arm may be modilied to suit gramophones of different types. Thus, in gramophones where the turntable or the record is adapted to extend in close proximity to the base of the tone arm, the end of the spring plate or arm may be bent so as to provide a part extending inwardly over the edge of the turntable or of the record and adapted to be engaged by the member carried by the tone arm, while in other cases the tone arm mounting may necessitate the formation of the plate or arm so that the outer part thereof, which is engaged by the member carriedby the tone arm is disposed at a lower level than the main part of the plate 'or arm.

The invention is hereinafter described by way of example with reference to the accompanying diagrammatic drawings, in which Figure 1 is a plan view of an automatic stop according to the invention indicating the manner in which it is arranged upon the grainophone Figure 2 is a section on the line 2- 2, Figure 1;

Figure 3 is a detail plan View illustrating a modified method of restricting the angular movement of the spring member shown in Figures 1 and 2;

Figure a is a sectional elevational corresponding to Figure 3-;

Figure 5 is a side elevation illustrating a modified construction of; stop, thepositions or" the gramophone tone arm, turntable and motorboard being indicated diagrammatically;

Figure 6 is a plan view of the spring member shown in Figure 5;

Figure 7 is a side elevation of a further modification of spring arm; and

Figure 8 is a plan view corresponding to Figure 7.

In carrying the invention into effect according to one preferred construction and with reference to Figures 1 and 2 of the accompanying diagrammatic drawings, an arm a of flat springy metal is fixed pivotally to the motorboard Z) of the graniophone as by means of a screw a at or adjacent its inner end, the spring arm being substantially radially disposed with respect to the turntable 0. The spring arm a is bent so that its outer part a is substantially horizontally disposed at a suitable height above the mo torboard and so that a brake blockrl or the equivalent carried by the arm a in a suitable position is normally pressed against the under side of the rim 0 of the turntable 0 as shown in dotted lines.

In order that the outer part a of the arm a may be depressed and held in the depressed position during the playing of a record so as to release the brake block (Z from the rim 0 the tone arm 6 is fitted with a downwardly extending pin or projecting part 6 which engages at its lower end upon the outer part a of the arm a so that the latter is depressed by the weight of the tone arm. In a determined position the outer part a of the arm (Z is provided with a hole or recess a into which the pin a is received when the reproducing needle reaches the end of the rec ord groove or other predetermined position, so that the outer part a of the arm a is then permitted to rise so as to press the brake block (Z against the under side of the rim 0 to bring the turntable 0 to rest. By adjusting the position of the arm a about its pivot aflthe position at which the ton arm 0 is disposed when the turntable 0 is brought to rest, may be varied so as to permit the device to be used with records of different sizes. The arm a is held in the position to which it is adjusted by means of friction and its angular movement ma be restricted by means of fixed stops 7), b fitted to extend upwardly from the motorboard. Alternatively, as shown in Figures 3 and 4, the angular movement of the arm a about its pivot a may be restricted by providing a washer a having downwardly extending projecting parts a adapted to engage with the motorboard so as to lock the washer fixedly in position when the screw a is tightened down. The washer a is provided with an upward- 1y extending. projecting part a which extends through a slot (1 'in'the arm a, which slot; is, of slightly greater width than the projection a to permit of slight angular movement of: the armaabout its pivot. The brake block (Z may be adjusted longitudinally with respect to the arm a as by mounting it slidably in a slot a in which it may be held by means of a clamping screw or otherwise.

According to a modification, which is especially applicable to gramophones wherein the turntable or the records placed thereon extend. close to the base or vertical portion ot-the tone arm 0, the arm a may have its outer part a bent so as to provide an inwardly extending part a disposed at a level above the record surface, the downwardly extending pin 6 upon the tone arm 6 engaging upon this part a, while the brake block (Z may be mounted upon the arm a in a suitable position to engage with the rim 0 of the turntable 0 as hereinbefore described. Fixed stops may be provided as described. In order to economise in material the bentover part a of the arm may be sector-shaped as shown in Figure 6.

According to a further modification applicable to gramophones wherein the mounting of the tone arm necessitates the disposition of the outer part a of the arm a at a lower level thanthe motorboard b, the arm a, may be suitably bent or stepped down so that the outer part a is horizontally disposed and at a substantially lower level than the main part of the arm a. The outer edge (19 of the arm maybe formed to acurvature having its radius approximately coincident with the pivotal axis 01 the tone arm.

In order toset the automatic stopaccording to the invention, the tone arm is moved so that the pine extendin downwardly therefrom engages in the hole or recess a in-the outer part of the arm a and the reproducing needle is placed upon the record in a position, for example, at the end of the record groove. The tone arm 0 is then raised vertically until the pin a disengages from the hole or recess (a and so that the setting of the arm a is not disturbed,- and is then swung back so thatthe reproducingneedle may be applied upon the recordat the starting position. It

will be readily appreciated that when the tone arm 6 has been traversed by the engagement of the reproducing needle with record groove to the position at which the needle was applied for setting the stop, the pin 6 will be received into the hole or recess a so that the brake block all is allowed to engage with the .under side of the rim 0 of the turntable a so that the latter is thereby automatically arrested. It will be understood that the usual brake device may be dispensed with so that as soon as the needle is applied upon the record at the starting position, the arm a is depressed and permits rotation of the turntable.

In the arrangement shown in the drawings the brake block d is adapted to make direct contact with the underside of the rim 0 of the turntable 0.

What I claim is 1. An automatic stop for gramophones, including an inherently resilient plate mounted relative to the motor board for swinging about a vertical axis, a brake block carried by the plate and arranged to engage the turntable when the plate is free to move under its own resiliency, a projection on the tone arm to engage the free end of the plate and depress the same to a position to maintain the brake block free of the turntable, said plate being formed with an opening to permit the passage of the projection on the tone arm to pass therethrough when the tone arm has reached the end of the record to release the plate to apply the brake block to the turntable under its own resiliency, and means for limiting the swinging movement of the plate.

2. An automatic stop for gramophones, including an inherently resilient plate mounted relative to the motor board for swinging about a vertical axis, a brake block carried by the plate and arranged to engage the turntable when the plate is free to move under its own resiliency, a projection on the tone arm to engage the free end of the plate and depress the same to a position to maintain the brake block free of the turntable, said plate being formed with an opening to permit the passage of the projection on the tone arm to pass therethrough when the tone arm has reached the end of the record to release the plate to apply the brake block to the turntable under its own resiliency, and a stop for limiting the swinging play of the plate, the position of the stop being variable to permit the plate to be moved on its pivot into a position providing for its control by the tone arm in the playing of a particular record.

3. An automatic stop for gramophones, comprising an inherently resilient plate mounted relative to the motor board for swinging about a vertical axis, a brake block adj ustably mounted on the plate and adapted under the normal resiliency of the plate to engage and brake the turntable, the free end of the plate being arranged adjacent the tone arm, a projection depending from the tone

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