Patent GB-461651-A (GB)
Title: Improvements relating to indicating and/or recording mechanism for weighing apparatus
IPC: G01G23/18
Filed: 1935-08-22
Abstract: 461,651. Electric signalling systems. AVERY, Ltd., W. & T., and LEESON, A. Aug. 22, 1935, No. 23539. [Class 40 (i)] [Also in Group XL] An indicating and /or recording mechanism for weighing-apparatus embodies a light-projecting system, a lightsensitive unit, a member which is displaceable with the load and provided with transparent and non-transparent portions arranged to correspond to weight values of several orders of weight, a displaceable scanning device associated with each order of weight and provided with transparent and non-transparent portions arranged in correspondence with the corresponding portions of the member displaceable with the load, setting means moved in unison with, and controlled by, the scanning device for setting the indicating and/or recording unit, and electrically-controlled locking means for locking the scanning devices when they arrive at positions wherein the light is allowed to pass to the light-sensitive unit. An opaque quadrantal chart 5 attached to the load-operated pendulum 4 is provided with three sets of slots 6<a>, 6<b>, 6<c> representing respectively cwts., quarters, and lbs. Each set of slots co-operates with a separate scanning slide such as lla, apertured in a manner similar to the chart 5. The scanning slides are each connected by a rod 11<d> to a corresponding bellcrank setting lever 12, the setting levers being urged towards cams on an operating shaft 29 by means of spring-pressed levers 15. The levers 15 are connected to rack bars 18 actuating type wheels 20 and indicating discs 22. A slotted screen 24 is disposed between the quadrantal chart 5 and the scanning slides 11<a>. A lightprojecting unit 8, 9, 10 slides in guides 7 embracing the chart 5, and the light-sensitive cell 26 moves transversely across the scanning screens 11<a> these movements being effected in timed relation by mechanism connected to the operating shaft 29. After depositing the load on the weighing platform the quadrantal chart 5 assumes a position corresponding to the weight. The operating shaft 29 is rotated, manually or by a motor, and the light-projecting unit is thereby moved successively to the lbs., quarters, and cwts. slots in the quadrantal chart 5. The scanning slides 11<a> are also displaced successively until their positions allow the light to pass through the chart 5 and screen 24 to the lightsensitive cell which moves into position in synchronism with the scanning slides The energization of the cell causes solenoids 14 to actuate detents 13 and arrest the setting levers 12 in positions corresponding to the weight of the load. Further rotation of the operating shaft 29 frees the follow-up levers 15 which then move up to the setting levers and at the same time set the printing and indicating discs 20, 22. The final movements of the operating shaft actuate the printing mechanism and restore the parts to their initial positions. In the event of a weight indication being within one-half unit of the next higher order of weight units, the appropriate setting lever 12 completes a circuit through a corresponding solenoid 25 which tilts the screen 24 in favour of the higher unit to ensure a definite change-over of the units. In a modification the light projection system is stationary, the light from the projection system being of such an area as will effectively cover the zone of traverse of the light sensitive unit.