Patent GB-306724-A (GB)
Title: Improvements in automatic weighing and recording mechanism
IPC: G01G19/00
Filed: 1928-03-09
Abstract: 306,724. Haddan, R., (Merrick Scale Manufacturing Co.). March 9, 1928. Variably-applied weight apparatus.- An automatic weighing mechanism comprises a weighing beam with load-supporting means, adjustable counterpoise means to balance the beam with the load-supporting means in the no-load condition means co-operating with the beam to support the counterpoise means and operative to adjust the counterpoise means to apply variably, or to relieve, the beam of the weight of the counterpoise means when the weighing mechanism is moved out of balance by the application or removal of the load, operating means for the counterpoiseadjusting means normally disconnected thereform when the weighing mechanism is in no-load and balanced position, and means controlled through the movement of the weighing mechanism out of balance operative to couple the operating means with the counterpoise-adjusting means and to actuate the same to adjust the counterpoise means to bring the weighing mechanism into balance. The load-receiving platform 136, Fig. 2, is supported upon a beam 146 movable between stops 157a, 158, flexible strips being used at the pivotal points. From one end of the beam is pivotally suspended by a flexible strap 157, a sector 161 carrying counterpoise weights 162. The sector is connected by a flexible strap 164 to a segment 166 pivoted on a shaft 170. A roller 171 on the segment 166 rests on a cam 38. Rotation of the cam in the appropriate direction causes the counterweights to move nearer to, or further from, the vertical line through the supporting end of the beam and thus to balance the load. The cam is set in rotation, as described below, when the load on the platform causes the weigh-beam to move into contact with one of the stops 157<a> or 158. An arm 158 on the weigh-beam is connected by a bar 176 and lever 181 to a rockable frame 199 carrying a wheel 16 bearing with its edge on a continuously rotating disc 15 secured upon a shaft 14 driven by a belt 8, Fig. 1, from the main shaft 3. When the weigh-beam is displaced from its equilibrium position the rockable frame 199 is turned about a longitudinal axis so as to change the plane of rotation of the wheel 16 which then moves radially on the disc 15 and causes the rockable frame to tilt about a transverse axis. The other end 216 of the frame in tilting actuates a switch mechanism 237 so as to energize one or other of two electromagnetic clutches 17, 18, driven from a constantly-rotating shaft 11. The operative clutch then drives a shaft 24 in the appropriate direction and this shaft, operating through intermediate mechanism performs two functions, (1) rotates the cam 38 to adjust the counterpoise 162 and bring the balance into equilibrium in which position the drive is again disconnected, and (2) drives the type wheels of a recording mechanism 45<a> to an extent corresponding to the rotation imparted to the cam 38 thus setting the type wheels according to the load. Excess rotation of the cam 38 is prevented by a switch opener 39 rotating with the cam so as to render the active clutch 17 or 18 inoperative at the limiting positions of the cam until the conditions of loading are remedied. When the mechanism is restored to equilibrium position after loading, the switch mechanism 237 re-assumes its central position and thereby energizes a magnet 79 which releases a frictionallv-driven contact actuator 94. The contact actuator moves slowly to close two contacts 91, 92 and thereby energizes an electromagnet to liberate a justifying lever 63 for the recording mechanism, the movement of the justifying lever opening the main circuit and rendering the weighing mechanism inactive. The time taken by the contact actuator 94 to close the contacts 91, 92 determines the time allowed for the weighing operation and this time may be varied by adjusting a nut 84 on the actuator mechanism. In a modified construction, in order to permit of a greater rocking movement of the rockable frame 199 and the contacts actuated thereby, the friction disc 15 is made with a concave driving surface. Printed records, apparatus for giving.-A cam 5 on the main shaft 3 vibrates a nose piece carried by the spring-pressed justifying lever 63 so that, when the justifying lever comes into action the nose engages a star wheel and ensures a definite setting of the type wheels which have previously been positioned by the driving-mechanism of the load-balancing devices. The justifying lever is connected by a shaft 267 to a printing platen 266 which is thereby actuated to make a record when the justifying lever is moved into engagement with the star wheel.