Patent GB-847261-A (GB)
Title: Improvements in or relating to weighing machines
IPC: G01G13/24
Filed: 1957-06-20
Abstract: 847,261. Weighing apparatus. WATTS, J. R. June 18, 1958 [June 20, 1957; Nov. 29, 1957], Nos. 19470/57 and 37217/57. Class 143 A weighing machine comprises means for receiving successive quantities of material to be weighed including a plurality of receptacles, mounted on a weight responsive element for movement which presents the receptacles successively at a loading station, means for retaining one of the receptacles at the loading station and means responsive to the movement of the weight responsive element which releases the receptacle when fully loaded and allows the commencement under gravity of a movement to bring the next successive receptacle into loading position and the filled receptacle into position in which the contents are discharged and brake means which produce a torque opposing said movement. The machine shown consists of a weigh beam 3 mounted on knife edges 4 supporting a counterweight 6, and a movable frame 8 on which a drum 11 divided into e.g. four compartments is revolvably supported, rotation of the drum being prevented by a roller 37 on the end of a lever 34 engaging a stop on a wheel 28 geared to the axle of the drum. Material e.g. grain is fed into a hopper 17 the lower end of which has a feed orifice controlled by main and dribble valves 19, 20 which are closed by toggles operated by stops on the frame of the machine as the frame 8 descends. Closing of the dribble valves causes a lever to displace the lever 34 and then releases the drum for a quarter revolution, during which the load is discharged and a fresh receptacle is brought into position for feeding. The vertical movement of the frame 8 is controlled by dashpot 44. The rising movement of the frame after discharge of the load re-opens the valves 19, 20. To enable repeated weighings to be carried out the machine is provided with a detent wheel 100, Fig. 11, coupled by a chain and sprocket drive to the shaft of the drum and having a series of teeth 102 controlled by a pawl on a stirrup 108 having a coil spring 113 tending to hold the pawl in engagement with one of the teeth 102. A unit control disc 114 coaxial with the shaft of wheel 100 carries an arm 119 having an inturned end 142 which on rotation of the disc 100 releases the pawl from the tooth 102 with which it is engaged. A multiplier control wheel 101 having teeth 124 on all but a small section 125 of its periphery co-operates with a pawl 129 on an arm 126 of a bellcrank lever, the other arm 127 of which co-operates with a stop 130. On the face of the wheel 101 is a circular flange 136 having a gap 137 and co-operating with an arm 138 on a lever 133 carrying a roller 134 which engages a projection 74 on the shaft of the wheel 28. The arrangement is such that the roller 134 is held clear of the projection except when the arm 138 enters the gap in the flange 136 in which position the pawl 129 idles on the untoothed portion 125 of the wheel 101. The disc 114 and wheel 101 are set so that the product of the setting is equal to the required number of weighing cycles. The disc 114 then causes re-cycling of the mechanism the disc 100 advancing one tooth for each cycle until the end 142 of the arm 119 releases the pawl from the tooth 102 and the stirrup 108 then rocks the arm 127 to bring the roller 134 into engagement with the stop 74. If, however, the arm 138 is resting on the flange 136, the roller 134 is held clear of the stop 74 and the pawl 129 is advanced one step. The cycle is then repeated until the pawl 129 reaches the untoothed portion of the wheel 101 and the arm 138 enters the gap in the flange 136.