Patent GB-315896-A (GB)
Title: Improvements in driving machanism for gramophones and like machines
IPC: G11B19/00
Filed: 1928-03-19
Abstract: 315,896. Gibbons, F., and Aylwin, W. March 19, 1928. Driving. - Weight driving mechanism for gramophones. or like machines is characterized by the provision of a counterweight or weights which, when the driving mechanism is being energized, drop and assist in raising the driving-weight or weights, the counterweights being subsequently raised again by a further operation not affecting the driving weights. By this means, the total effort required is distributed. The raising of the weights may be effected either by opening and closing the lid of the case, or by rotation of a handle, or by means of a hand lever or one or more pedals. Figs. 1, 4, and 5 show a construction wherein a pair of arms e<2> pivoted on a shaft e<3> each carry a driving weight e<4>, one of the arms having a chain e connected thereto which passes over a free-wheel sprocket on a shaft b, from which the turntable spindle a is driven by bevel gearing. Two arms g secured to a shaft g' each carry counterweights g<2>, one arm g being connected by a link f<3> to one arm of a bell-crank lever f, the other arm of which has an end of the chain e attached to it. A chain h connected to one of the arms g passes round a wheel j keyed on a countershaft j<1>, the other end of the chain being attached to an end of one of the arms e<2>. A coiled spring acting on the shaft j<1> ensures that the part h<1> of the chain h is always taut. A crank k<1> keyed to the shaft g<1> is connected by a link k to the lid l of the casing. A brake drum is provided on the countershaft j<1>, and is normally acted on by a coiled spring m<1>, the braking action of which can be taken off by pulling out a rod m<3>. The operation of the machine is as follows. With the counterweights g<2> held raised by the action of the brake m<1>, the arms e<3> fall to their lowermost position, as shown in Fig. 4, driving the turntable. Then on lifting the lid, after releasing the brake on the countershaft, the counterweights g<2> fall, Fig. 5, and the driving weights e<4> are raised to their uppermost position. The brake m<1> is then again applied and the lid is closed. This action raises the counterweights, and the whole mechanism is thus re-energized, the parts being in the position shown in Fig. 1. One of the arms e<2> may be extended so as to operate the rod m<3> and thus apply the brake m<1> when the driving weights are raised. In a modification, the countershaft j<1> may be rotated directly by means of a handle and clutch, to re-energize the driving mechanism. Further modifications are described in which, instead of using the link k connected to the lid to rotate the shaft g<1>, and thereby to raise the driving weights and counterweights, this may be done by reciprocating a hand lever linked to the shaft g<1> and projecting through the front of the casing; or two pedals, adapted to be operated successively, may be connected by linkwork to the shaft g<1>. Fig. 9 shows another construction, in which a driving weight u<3> is connected by a chain u<2> to a counterweight u<4>, the chain passing over a freewheel sprocket d on the motor shaft and over a wheel u<5> keyed on a countershaft j<1>. A segmental rack u secured to the lid engages a free-wheel pinion u' on the countershaft, and a similar rack (not shown) engages a free-wheel pinion integral with the chain wheel u<5>. By raising and lowering the lid, the driving-weight u<3> and the counterweight u<4> are lifted in succession. The Provisional Specification also describes mechanism for winding a gramophone spring motor by opening the lid of the casing.