GB431805A - Improvements in and relating to machines adapted for use in packing predetermined weights of material - Google Patents

Abstract

431,805. Weighing and filling machines. LYLE, O., and TATE & LYLE, Ltd., 21, Mincing Lane, London. March 28, 1934, No. 9670. [Class 143] In a machine for weighing syrup, &c., into jars or other receptacles and compensating for the variations in tare of the receptacles, the scale beam supports during the weighing operation a periodically - replenished liquidcontaining vessel furnished with a constant level overflow and containing a buoyant member or scale pan on which the receptacles are successively placed so that variations in the tare of the receptacles cause displacement, by way of the overflow, of varying quantities of liquid to compensate in the subsequent filling and weighing operation for the differences in the tare. Assuming that a receptacle has been filled, a cam shaft 16 controlled by an electric contact is automatically set in rotation and operates gripper mechanism 129 to move the filled receptacle and two empty receptacles 8 one step to the left thereby bringing the foremost empty receptacle on to the scale pan 7. The scale pan is carried on a float 6 immersed in water in a vessel 4 carried by the scale beam 1. A drip tray 148 is temporarily moved beneath the feed valve 83, and a pump 22 is actuated to introduce a predetermined amount of water into the vessel 4. A support 9 now rises to lift the vessel 4 with its floating scale pan temporarily off the scale beam, at the same time leaving the float free to displace water down an overflow 5 according to the tare of the empty receptacle. If the empty receptacle be two heavy or too light one or other of two contacts 40 or 42 is closed by arms 39, 41 attached to the float, in either case short-circuiting a magnet 94 and thereby preventing the opening, as described below, of the feed valve 83. The continued rotation of the cam shaft causes further movement to the left of the receptacles until a receptacle falling within the prescribed limits of tolerance is brought on to the scale pan, the vessel 4 being lowered on to the scale beam in the normal operation of the machine. A cam-operated switch energizes the magnet 94 to move a stirrup 90 into the path of a cam-operated hook 95. The hook on engaging the stirrup pulls down a lever 88 and opens the feed valve 83. The movement of the lever 88 closes a switch 102 and thus short-circuits a holding inductance 79 and releases the scale beam from its attraction. The right-hand end of the scale beam falls and operates a system of switches to energize two inductances 104, 105 secured to a lever 106. The inductance 105 is now held by attraction against a stationary armature 107 and the inductance 104 attracts an armature 103 on the valve spindle to keep the valve open. A further magnet is energized to disengage a clutch and stop the cam-shaft 16. The material accumulating in the receptacle deflects the scale beam, and a weighted lever 56 pressing thereon comes to rest against a stop, at the same time closing a contact switch 71 and short-circuiting the inductance 105. The inductance then swings upwards against a stop 108 and the feed valve descends by gravity to reduce the feed to a trickle. Further movement of the scale beam similarly allows a second lever 56 to close a further contact and short-circuit the inductance 104, allowing the valve to close completely. At this stage a continuously-rotating cam imparts a succession of sharp pulls to the hook 95 thereby opening and closing the valve slightly to deliver drops to the receptacle. When the desired weight is made up the scale beam swings and by operating a contact causes reenergizing of the holding inductance 79 to hold the scale beam, short-circuiting of the magnet 94 to disconnect the stirrup 90 and close the valve finally, and restarting of the cam shaft to repeat the operations.