Patent GB-884209-A (GB)
Title: Improvements in or relating to automatic weighing and totalising apparatus
Inventor: DENISON HENRY MARTYN
IPC: G01G21/00
Filed: 1958-09-24
Abstract: 884,209. Weighing apparatus. DENISON & SON Ltd., SAML. Sept. 21, 1959 [Sept. 24, 1958], No. 30455/58. Class 143. Automatic weighing and totalising apparatus includes a weight-sensitive element rotatable in accordance with a load applied to weightsensitive lever mechanism, a detecting arm rotatable coaxially with the weight-sensitive element to measure its angular deflection, and clutch-operated means whereby a measure of this deflection is transmitted from the arm to totalising mechanism. The sequence of events in each weighing and totalising operation is controlled by cams whereby it is ensured that the detecting arm moves into engagement with the weight-sensitive element and is subsequently released from such engagement and returned to a zero reference position, the clutch being operated to couple the movement of the arm to the totalising mechanism during the return of the arm. As shown, the weight-sensitive element is a sector 12 freely mounted on an axle 11 about which it is driven by means of a ribbon 9 attached to the weighing mechanism and to the surface of a ribbon cam 10 rigidly connected to the element 12. The apparatus is intended for use with a conveyer whose drive rotates a shaft 21 once for each passage of a weigh-length of the conveyer over the weighing mechanism. Once in each cycle a brake 17, normally spring-held in contact with the profile of element 12, is released by the action of a cam 20 rotated by the shaft 21 to enable the weight-sensitive element to respond to the load, after which the brake is reapplied. A cam 22 on the same shaft which engages a roller 23 mounted on the outer end of the detecting arm 15 subsequently allows the arm to fall until a contactor 14 carried by the arm is engaged by a pin 13 protruding from the sector 12. The contactor 14 is retractable from the pin by being pivoted to the arm 15 so that on the release of a spring-loaded frame 44 (Fig. 3) by the cam 41, movement of the frame to the right as shown causes a protruding rod 48 on the frame to disengage the contactor 14 from the pin 13. The same movement of the frame 44 couples the elements 28, 29 of a conical clutch by which the arm 15 is coupied to a sprocket wheel 31 from which the totalising mechanism is driven. After disengagement of the contactor and engagement of the clutch, further rotation of the cam 22 returns the arm to a zero reference position defined by the periphery of the sector X of the cam, this motion from the position of engagement with the element 12 to the zero position being transmitted to the totaliser. Finally, a side-cam 24a on the cam 22 re-sets the contactor 14 for the next weighing. Should the load be less than that corresponding to the zero reference position of the cam (which position corresponds to the average tare load) the detecting arm is brought back to the zero reference position by the engagement of a roller 25 carried by the arm 15 with the inner surface of a cam 24. To allow for the possibility of such sub-zero loads, the cam 22 is designed to raise the detecting arm beyond the zero reference position after disengagement of the clutch. Visual indications of the load being weighed and the total of the loads which have been transmitted to the totaliser are provided by pointers (not shown) movable by spindles driven in accordance with the movement of the element 12 and the sprocket wheel 31 respectively. Specifications 9339/1895 and 367,159 are referred to.