GB284029A - Self-contained hydraulic means for driving gramophones - Google Patents

Abstract

284,029. Johnson, O. C. Oct. 27, 1926. Driving; starting and stopping; speed ,regulating.-A gramophone is driven by a motor comprising a compressible spring S acting on a piston E in a cylinder B containing oil or other fluid, the fluid being forced, as the spring expands, through ports H<3> in a valve ring H fixed in a casing B<1> above the cylinder, into oscillating members K, pivoted on the ring and having cylindrical arms in which piston rods T work; these arms carry sleeves N, which are connected to the pistons T and which are all coupled to a crank-pin 0 on an arm O<1> fixed to a shaft O<2> supporting the turntable O<4>. Exhaust ports H<4>, formed in the ring H beneath the members K, lead to the inside of the ring, while the inlet ports H<3> all communicate with a circular groove H<2> connected by a duct Z to the cylinder B. An orifice B<2> connects tha interior of the ring to the portion of the cylinder B containing the spring. Thus as the sleeves N reciprocate, driving the turntable, the members K are oscillated, putting the inlet and discharge ports H<3>, H<4> alternately in communication with the cylindrical passages in which the rods T work. Power is stored in the spring S by mechanism which may be actuated by movement of the lid of the gramophone casing. The mechanism comprises bell-crank levers C<\> C<2>, which are both secured to a shaft C', free to turn in a bearing or collar C' slidably mounted on a rod C<6>. The short arms of the bell-crank levers are connected, through links C, to the outer end of the piston-rod E<3>. With the spring S unstressed, as shown, the collar C<5> is engaged by a pivoted detent C<7>, held in locking position by a spring S<1>. To start the machine, the upper ends of the levers C<2> are depressed, for example by closing the lid of the casing, (which may be connected to the levers for this purpose), and the piston E is thereby moved along the cylinder B, compressing the springs S, whilst oil flows past the piston-head. Then the detent C<7> is moved so as to release the collar C<5>, and the spring expands, driving the machine as previously described. The release movement of the detent C<7> is effected by rotating a rod G by means of a handle G<2>, the rod carrying a pin G<1> which depresses the outer end of the detent. At the same time, a friction pad G<3> is moved away from the turntable. The speed of the machine is governed by providing on the turntable spindle O<2> radial extensions of the arm O<1>, the ends of which have attached thereto, by means of leaf springs, weights P' carrying friction pads. The pads bear against a coned surface P<3> on the inside of the casing, and the vertical position of the friction pads relatively to the surface P<3> is varied as desired, to control the speed, by raising or lowering within the casing a bush O<6>, together with the spindle O<2> passing through it, and all the parts carried by the spindle. This vertical adjustment is effected by means of a rod M<2> passing through an oblique slot in the casing.