Patent GB-1208441-A (GB)
Title: Improvements relating to targets
Inventor: KNIGHT LINDSAY CHARLES
IPC: F41J5/056
Filed: 1967-01-31
Abstract: 1,208,441. Target apparatus. AUSTRALASIAN TRAINING AIDS PTY. Ltd. 29 Jan., 1968 [31 Jan., 1967], No. 4735/67. Heading F3X. The invention relates to a hit detecting device for a target apparatus comprising a plurality of targets 21, target moving means for each target for moving each target between an operative and an inoperative position and a hit detecting device associated with each target to detect the impact of a projectile striking the target. Target control means are also provided for each target and are selectively operable to control each target moving means to cause a target to be moved to an inoperative position when struck by a projectile or to hold a target in the inoperative or operative position in response to predetermined control signals. The detecting device comprises at least one impact-sensing device, e.g. an inertia switch 7, which produces electrical pulses in response to a projectile striking the target. The first of the pulses triggers the operation of associated electrical circuitry which is arranged to clamp electrically the impact sensing device for a predetermined time to prevent further electrical pulses produced thereby passing to the associated circuitry and to produce simultaneously and transmit a second electrical pulse having a predetermined amplitude and duration to the target control means. In the construction shown the clamping is effected by a pulse from a multivibrator 6 which is fed by a further multivibrator 5, the latter multivibrator producing the second electrical pulse. A further pulse of lesser amplitude than the second pulse is derived from the multivibrator 5 by means of a resistor, this further pulse being fed to an integrating amplifier and thence to an emitter follower amplifier to provide the correct impedance to line (Fig. 4, not shown). The second pulse is fed to a clamping amplifier into which a hold signal may be introduced. A clamping signal may be fed into the clamping amplifier to prevent any feed back from the detecting device when detonators are set off adjacent the target to simulate return gunfire. The output of the clamping amplifier is fed to the target motor across a capacitor. The detailed transistorized circuits of the multivibrators 5, 6 and amplifiers are disclosed with reference to Figs. 3 and 5 (not shown). A target for use in the above-described circuits comprises a sheet of synthetic plastics material formed into a rigid body 21 as by vacuum moulding which sheet is provided with a backing of mesh or fabric material moulded into and/or adhesively fixed to the rear surface thereof (Fig. 8, not shown). The body 21 is formed with flange portions 22 around the edge thereof and longitudinal ribs 23 or grooves. Slots 26 are provided for facilitating the clamping of the target in a target holder. In a further embodiment a target is provided with four strengthening ribs (Figs. 9, 10, not shown). The targets may be of a butadiene styrene (A.B.S.) with a charcoal pigment or polyethylene, the mesh fabric of fibreglass or canvas and the adhesive of a resinous adhesive compound.