| 摘要 |
The box (2) and the knock-down device (3) have shafts (4) which are separate, and displaced in a depth direction. They are electrically connected to spread strips fastened to wooden planks (41), and are mechanically connected to wires, one end of which is fastened in drawbar couplings (44), while the other end is formed as a loop located around pins. - Where the projectiles used are of metal, or of plastic, a target board (6) requires to be used. When a metal projectile makes contact between two metal strips, a power circuit is closed, activating via the strips (40), box (2) and a contact an electrical component. This component frees a stop, allowing the target board (6) to drop. When a plastic or other non-electrically conductive projectile hits, vibrations are caused in the target board. These are monitored by indicators which close an electrical circuit, producing the same sequence of events as with a metal projectile. |
