Patent GB-698630-A (GB)
Title: Improved load computing apparatus for aircraft
IPC: G06G5/00
Filed: 1950-10-26
Abstract: 698,630. Calculating-apparatus. CARREYETTE, J., and BRITISH OVERSEAS AIRWAYS CORPORATION. Oct. 22, 1951 [Oct. 26, 1950], No. 26153/50. Class 106 (i). A computor for assessing the position of the centre of gravity of a loaded aircraft comprises load members for the various loading points and an indicator having two mutually adjustable parts, one of which is adjusted by the load members directly according to the sum of the loads and the other according to the sum of the load moments about a datum, so that the relative position of the indicator parts shows the position of the centre of gravity relative to the datum. The apparatus shown has a weightsetting handle 5 and two rows of push-buttons 4, corresponding to the loading bays of the aircraft, operation of a push-button coupling the handle to a corresponding load-registering lead-screw 51. The lead-screws are arranged in two rows adjacent long pinions 32 extending across the apparatus and connected to the handle 5 by bevel-gearing 22, 24. Associated with each push-button 4 is a cradle 35 carrying three intermeshing spur-wheels, the central wheel 33 being in permanent mesh with the long pinion 32, whilst the two outer wheels engage respectively a long pinion 38 and a spurwheel 39 fast with a bevel gear 48 which drives the lead-screw 51. A captive nut 94 on each lead-screw is followed by a spring-loaded arm 96, and a slotted bar 99 (Fig. 10) on the arm 96 engages a pin 103 fixed to the head 105 of a vertical rod 106. The pin 103 is pre-adjusted along a slot 104 in the head 105 according to the distance of the respective loading bay from the datum, and so that the rod 106 is displaced according to the moment of the load about the datum. The moments of all the set loads are added by a ribbon 111 passing round pulleys 108 at the lower ends of the rods 106 and intervening guide pulleys 112. A similar ribbon 111A adds the moments registered by the rear row of lead-screws 51, and the free ends of the ribbons are connected to a ribbon 115 looped round a pulley 116 displaceable against a spring 117. A rack 118 carried by the pulley 116 traverses a carriage 123 bearing a chart 7 laterally of the apparatus according to the total moment registered. The anchored end of one ribbon 111 is taken round a pulley 126 adjustable according to the unladen moment of the aircraft by means of a key 13 applied to a screw 129 ; this adjustment is indicated by a dial 136 at a window 14. The loads registered by the individual lead-screws 51 are registered by counters 3 at windows 2 adjacent the respective push-buttons 4 and driven by the abovementioned spur-wheels 39. The two long pinions 38 register the total load and their movements are transmitted through bevel gearing 63 and 65, a shaft 64 and worm 70 to a vertical screw 72 which traverses a load index 8 vertically over the chart 7. The shaft 64 also drives a total load counter 69 at a window 9. The unladen weight of the aircraft is registered by applying a key to a shaft 11 which is then clutched-in to drive the counter 69 and index 8 ; the unladen weight is shown separately by a counter 79 at a window 10. The chart 7 may be marked with diagonal lines 7A for position of centre of gravity in relation to the datum, and unsafe positions be suitably distinguished as by hatching. Adjustable stop collars 110 are fitted to the lead-screws 51 to restrict movement to safe limits. Crowding locks interconnect the push-buttons to prevent simultaneous operation, and are also interconnected with the mechanism for entering the unladen weight. A form of apparatus described in the Provisional Specification differs mainly in that a common adjustable lever is employed to evaluate the load moments at all the loading points. Movement commensurate to a set load is applied to the lever at a distance from its fulcrum which is varied according to the position of the loading point.