GB113863A - Improvements in and relating to Repeating and Stopping Devices for Phonographs, Talking Machines and the like. - Google Patents

Abstract

113,863. Mitchell, F. B. March 28, 1917. Addition to 103,523. Returning sound-box to starting position; stopping; disk records.-Relates to stopping and repeating apparatus of the kind described in the parent Specification comprising a friction block suspended from the sound-box and arranged to swing down on to the record surface to act either as a brake or as a skid to return the tone-arm; and consists in modified means for mounting and operating the friction block, and in arrangements by which the record may be arrested after one or after two reproductions, or may repeat continuously. In the form shown in Fig. 1, the friction block C<3> is carried by an arm C pivoted on a pin C<7> and having a pivoted catch C<1> at its outer end. When a record is being played, the block C' is raised above the record, and the pawl C<1> rests on the surface in the position shown in dotted lines. The pivot C<7> is carried on a slide D working in a guide E rigidly secured to a clamp B surrounding the neck of the sound-box. A spring G tends to draw in the slide D which is normally held by the engagement of a flat spring F behind a spring detent E<2>. At the completion of a reproduction, a shoulder formed by a raised block or by a depression on the record strikes the catch C' and lowers the block C' on to the record, thereby lifting the sound-box. A leg on the arm C raises the plate spring F, and the tension spring G draws the slide D forward slightly until the spring F rides over the detent E<2>, further movement being prevented by a shoulder on the arm C engaging a pin H<1> on the guide E. The drag of the record on the block C<3> traverses the soundbox and tone-arm back to the record rim, and when the block passes the edge, the needle enters the playing groove at the starting position, and the arm C again takes up the position shown in dotted lines. This disengages the pin H' and allows the spring G to draw the slide D towards the sound-box. At the conclusion of the second reproduction, the block C<3> again engages the record surface, but at such a position, relatively to the record centre and the tone-arm pivot, that the outward drag on the block only traverses it a short distance before the record is arrested. The block C<3> is adjustable in a split spring socket C<9> by a screw. The arm C may be suspended by a flexible spring instead of a pivot. In a modification, shown in Fig. 3, the arm C is suspended from the outer end of a link B<4> which is pivoted to the clamp B and is pulled by a spring B<5> towards an upright arm B<1> on the clamp. The free end of a detent B<2> prevents the spring B<5> from operating. At the end of the first reproduction, the arm C is tilted as previously described and a lug thereon raises the detent B<2>, thus allowing the spring B<5> to pull forward the link B a short distance until the lug engages a tooth B<3> on the detent B<2>. The tone-arm is returned to starting position as before, and when the block C<3> passes the record rim, the return of the arm C to its normal position completely releases the detent B<2>, and the link B<4> is drawn close to the upright arm B<1>. At the close of the second reproduction, the block C<3> is again lowered and arrests the turntable. In a further modification, the friction block is of eccentric form and is mounted on a cranked spindle arranged transversely to the arm C which is centrally pivoted on a horizontal pin on the stem of the clamp B and has one arm in operative engagement with the crank on the spindle. The spindle is mounted in a bearing attached to a threaded sleeve screwed on the stem of the clamp B. Any suitable means may be provided for retaining the friction block in the two positions required for braking and repeating respectively. The friction block may be of the form shown in Fig. 1, and may be attached to an arm threaded on the clamp stem, this arm being given a movement in a horizontal plane when the catch arm C is operated, and causing the block to be lowered on to the record. In a modified apparatus shown in Figs. 6 and 9, the mechanism for obtaining two positions of the friction block relatively to the record centre and the tonearm pivot is dispensed with, and either stopping or repetition is effected according to the setting of stops R, S lying in the path of a pin A<5> on the vertical part A<3> of the tone-arm. A bracket P attached to the tone-arm socket A' supports two stop-plates R, S mounted on pivots P<2>, P<1>. As shown in Fig. 6, the stops are set for one repetition, the pin A<5> engaging the face S<1> of the stop S as the friction block passes the rim of the turntable on the return of the tone-arm after one reproduction. As the second reproduction proceeds, the pin A<5> recedes from the stop S and the stop R falls into the position shown in plan in Fig. 9, so that on the second return of the tone-arm the pin A' engages and is arrested by the) stop R before the friction block has reached the rim, thereby stopping the turntable. If it is desired to repeat continuously, the stop R nuay be clamped in an inoperative position by a screw R<2>, while the machine may be arrested after one reproduction by starting with the stops R, S in the position shown in Fig. 9. The apparatus is slightly modified for machines having an upwardly-bent tonearm.