Patent GB-907760-A (GB)
Title: Event recorder
Inventor: WAGNER ROBERT B
IPC: G01D9/14
Filed: 1959-12-18
Abstract: 907,760. Recording-apparatus. ACF INDUSTRIES Inc. Dec. 18, 1959, No. 43025/59. Class 106 (4). Recording-apparatus comprises a recording- head 6, Fig. 1, with a stylus 8 for making a trace 9, Fig. 3, on a platen 2 in response to a continuous input signal and means responsive to intermittent input signals for momentarily displacing the stylus 8 in directions 11, 12 at an angle to the trace 9, these displacing means comprising two groups of electromagnets 30 with a linkage interposed respectively between each group and the stylus 8 whereby one group deflects the stylus in opposite directions 14, 15 normal to the directions 11, 12 in which it is deflected by the other group when a change in the direction of the trace 9 selectively changes the electromagnet to be energized. The apparatus may be used in conjunction with stationary equipment for instructing air crews whilst simulating flight conditions. Two recording heads 6, Fig. 1, may record one on each side of a transparent platen 2, the traces representing respectively the courses of the training and enemy aircraft and events such as firing guns dropping bombs and other actions being recorded by momentary deviations such as 11 to 14, Fig. 3, each recording-head 6 is contained in a housing 18, Fig. 4, within which a reservoir 20 of ink supplies the stylus 8. The stylus 8 rests in a stirrup 26 attached to a leaf spring 24 secured to the bottom of the housing 18 and is secured by a clamp 40 to a shaft 38 passing through one stack of annular electromagnets 28 and secured at the centre of a disc 36. The disc 36 has four pivots 58a to 58d each resting in a slight recess in a frame 59a. The four armatures 30 are linked to the disc 36 at points midway between the pivots 58a to 58d so that when one electromagnet 28 is energized and attracts its armature 30 the disc 36 rocks about the line joining one pair of pivots deflecting the stylus point 10 to one of the four positions 10a to 10d to draw one of the lines 11, 12, 14 or 15. Lines 13 and 16 are drawn upon energizing two electromagnets in rapid succession and lines at an angle of 45 degrees to the trace are drawn by simultaneously energizing appropriate pairs of electromagnets. The trace 9 may be made intermittent by energizing at intervals another electromagnet at the bottom of the stack beneath the disc 36 to lift the stylus through raising the stirrup 26. Damping is provided by a dashpot 46 above and between each pair of pivots of the disc 36, the dashpots also providing restoring forces to return the armatures 30. The trace 9 is plotted by moving the head 6 vertically on a carriage 4 and the carriage 4 horizontally in accordance with input signals. As shown in Fig. 4 the carriage 4 is of channel section provided with conducting rails 54 in an insulated inset 52 for co-operation with brushes 56 when the carriage is received in a recess 50 of the head whereby the various input signals may be passed to the electromagnets. Control circuitry is described with reference to Figs. 8, 9a, 9b (not shown). In another embodiment a disc 36 with three pivots 58 is used.