GB340905A - Improvements in and relating to gramophones - Google Patents

Abstract

340,905. Gramophones. ROBERTS, J. H. T., Dashwood House. Old Broad Street, London. March 17, 1930, No. 11910. Divided on 343,350. [Class 40 (ii).] Turntable accessories.-A turntable adapted to be used in conjunction with a standard gramophone is provided with means to rotate a record in the same direction as, but at a different rotational speed from, that of the gramophone spindle. The device is adapted to be placed upon, or in substitution for the usual turntable and is generally employed for the purpose of rotating a record at a speed of 30 revolutions per minute instead of at the customary 80 revolutions per minute. In Fig. 1 the device is shown as comprising a pair of discs 1, 12 with intermediate gear wheels 3, 6 all mounted on the same vertical spindle and supported on the ordinary turntable 8. The gear wheels 3, 6, which are each secured to its adjacent disc 1, 12, mesh with a pair of pinions 4, 5 carried by a stationary plate 9 disposed between the gear wheels 3, 6. The disc 9 carries a projecting part 13 which is screwed or pinned to the gramophone case. Ball bearings 10, 11 may be mounted between the discs 1, 12. The disc 12 may be dispensed with when the device is used in substitution for the ordinary turntable. The gear wheels 3 .. 6 may be replaced by friction wheels. The intermediate disc 9, lower disc 12 and gear wheel 6 may, alternatively, as shown in Fig. 5, be mounted loosely on a flanged member 19 which carries the upper disc 1 and gear wheel 3, and has a screwed flange 18 at its lower end. The member 19 fits loosely on the centre spindle of the gramophone and is provided with an upstanding peg 2. This arrangement of the member 19 may be modified by securing it to the lower disc and gear wheel and loosely mounting the other disc and gear wheel on this member. In another construction, a pair of coaxial friction wheels 14, 15 carried, if desired, by the plate 19 is adapted to engage under the action of a spring the edges of the two discs 1, 12 as shown in Fig. 2, or the wheels 14, 15 may be in the form of gear wheels engaging the toothed peripheries of the discs 1, 12. The plate 12 may be dispensed with, and the wheel 15 then engages the turntable periphery. Felt &c. may be provided on the upper surface of the upper disc and on the under surface of the lower disc.