GB601393A - Improvements in and relating to feeding or apportioning mechanism for machines for wrapping and packeting butter or similar plastic substances - Google Patents

Abstract

601,393. Automatic-feed weighers. BRECKNELL, MUNRO, & ROGERS, Ltd., and DOLMAN, H. J. July 3, 1945, No. 16938. [Class 143] Machinery for delivering butter or other plastic substance in apportioned pats by means of a piston forming a movable wall of a pat moulding chamber is regulated by means of a ratchet wheel adapted to be turned in opposite directions by two pawl elements drivable by electromagnetic solenoids controlled in response to the effect on weighing-apparatus of delivery thereto of under or over-weight pats, the ratchet wheel in its movements being arranged to effect adjustment of the setting of the piston to alter the capacity of the chamber. A shaft 71 carries a toothed ratchet wheel 1, Fig. 1, mounted between the limbs of a freely swinging U-cradle 16 and engaged by a pawl 13 when a solenoid 10 is energised, the pull of the armature 11 overcoming the spring 20. Adjusting screws 22, 24 permit the pawl to be set just clear of the ratchet and the number of teeth tripped or passed when the cradle is swung by spring 20 to be controlled. An identical assembly of parts associated with a solenoid 10A is disposed on the diametrically opposite side of wheel 1 tending to produce an intermittent movement thereof which counteracts that due to solenoid 10. The solenoids are energised by switches closed by a blade 30, Fig. 4, on a weigh beam 26 which moves in opposite directions according to whether the weighed pat is under or over weight, for example as described in Specification 601,392. Movement of the wheel 1 and its shaft, through pinion 67 and worm wheel 65, Fig. 5, carrying pin 64 engaging slot 66 in a bar 62 slidable along one arm of the rocker 63 operated by cam 70, varies the stroke of piston 59 forming a movable wall of the butter moulding chamber 58 forming pats in known manner. The necessary variation may be effected immediately a deviation in weight is discovered or, by using a fine tooth pitch, an adjusting movement necessary to correct the inaccuracy may require several impulses. Alternatively, means may be provided for delaying the correction of the apportioning mechanism until the control device has been operated a pre-arranged number of times. Thus each time an overweight load is applied, the beam closes a switch 34 and opens a switch 35, Fig. 4, energising a solenoid 36 which causes a pawl 40 to advance a ratchet disc 41 while a pawl 42 normally prevents return. After a determined movement, a cam 43 closes a switch 33 of solenoid 10A. A resetting solenoid 46 is connected to a cam 49 which is rocked on energising the solenoid to release the pawls 40, 42 and permit the disc 41 to return to zero position. A switch 53, in circuit with solenoid 46 and switch 35, is closed by a cam 54 on each swing of the beam. Another cam 55 simultaneously with the closing of switch 53 opens a switch 56 in the circuit of overweight solenoid 10A. Normally the resetting solenoid 46 is energised once for each cycle of the wrapping machine but, when an overweight load is on the scale 28, it is not energised but the delay solenoid 36 is energised and thus imparts an accumulated motion to the disc 41 due to successive overweights. Thus, if four pats of butter are undergoing wrapping between the delivery point and the place of checkweighing, the delay device is set so that no adjustment of the apportioning device is made until four successive impulses due to overweight pats are produced. A similar delay device is associated with underweight solenoid 10.