Patent GB-675007-A (GB)
Title: Improvements relating to automatic weighing machines
IPC: G01G13/00
Filed: 1949-11-29
Abstract: 675,007. Automatic feed weighers. AUTOPACK, Ltd.,SMITH, A. R., LEE, G. A., and HOPKINS, C. J. Nov. 2, 1950 [Nov. 29, 1949], No. 30550/49: Class 143  In an automatic feed weigher the slide n, which is actuated intermittently to throttle and finally cut off the feed of material, and pan discharge doors v are operated sequeritially by a pair of cams 8, 9 , Figs. 2 and 3, which are rotated by an epicyclic gear controlled by movement of the weigh beam s. The cam 8 co-operates with a follower 16 secured to an arm 10 which, through a link 18, reciprocates the slide n; and the cam 9 co-operates with a follower 17 secured to an arm 11 which reciprocates a push rod 20 to effect first raising of a latch 26, and then opening of the hinged doors v. These cams 8, 9 are connected by a pair of pins 37 which also constitute the spindles of planet pinions 31 which couple a driving sun wheel 29 and a driven sun wheel 30 both of which are rotatable on a shaft 12 relative to the - cams. A ratchet wheel 32 is secured to cam 8 and is normally free from engagement with pawls x<SP>1</SP>-x<SP>4</SP>-x<SP>5</SP>, and a friction brake band 39 exerts a restraining action on cam 9, 'so that continuous rotation of sun wheel 29 by worm drive 62 causes the planet pinions 31 to rotate sun wheel 30; the cams thus remaining stationary. At the instant in the weighing cycle when the beam s is about to move under the weight of material in pan r, all the pawls are disengaged from the ratchet wheel 32, pawls x<SP>2</SP>-x<SP>4</SP> and pawl x<SP>5</SP> being held respectively by cam tracks 42, 46 on cam 8 and pawl x<SP>1</SP> which has previously been released by cam 42 is held by a plate 44 secured to the beam s, and having a series of holes 52 which engage the free ends of the pawls. Initial movement of the beam frees pawl x<SP>1</SP> which is urged by its spring 40 into locking engagement with the ratchet wheel so preventing further rotation of sun wheel 30 and causing the planet pinions together with cams 8, 9 to rotate bodily about shaft 12, whereupon track 42 releases pawl x<SP>2</SP> which however does not engage the ratchet since it is held by plate 44, and, simultaneously, disengages pawl x<SP>1</SP> from the ratchet so again immobilizing cams 8, 9. This movement of cam 8 moves the slide n to its first throttling position. Continued movement of the beam causes pawls x<SP>2</SP>, x<SP>3</SP> and x<SP>4</SP> in sequence to be brought into and put out of action in the same way as pawl x, so completing throttling and cut off. At the same time as pawl x<SP>4</SP> is put out of action cam track 46 releases pawl x<SP>5</SP> which locks the sun wheel 30 and returns cams 8, 9 to their initial position, so opening and closing doors v and restarting the feed by opening slide n. Pawl x<SP>5</SP> also has a manual control, operable through a rod 47 and rotatable abutment 50, to.hold the pawl out of operation if it is desired to prevent the machine re-setting after a charge has been weighed out. Jigging, stirring and other mechanism for agitating material. A rubber roller 56 attached to a lever 55 is brought into sharp contact with a discharge shoot 53 at the end of each dumping cycle by a rod 57 operatively connected with the arm 11. A rotary cone c with an arm g, a rotary disc h with fingers i, and a bladed rotor p, all driven through a shaft o, ensure an even flow of material to the pan r. Scale beam loading devices temporarily operative for accelerating or retarding the movement of the scale beam. A shaft 2, Figs. 2 and 3, carries radial arms 3, 6; arm 3  being biassed by spring 4 into a vertical position and arm 6 engaging the beam s when it is in its unloaded position; the arrangement being such that the beam is given a temporary initial acceleration. The sequential contact of pawls x<SP>1</SP>-x<SP>4</SP> with plate 44 serves to minimize or counteract momentum of the beam.