JPS5780563A - Acceleration recording instrument - Google Patents

Abstract

PURPOSE:To measure acceleration at car crash, by a method wherein a plumb to detect acceleration of vehicles is movable assembled to a coil spring in cantilever support, and the plumb of prescribed weight is assembled to the case simply and accurately. CONSTITUTION:At bottom center of a case 10 is fixed a bush 21 to which one end of a coil spring 20 of piano wire is secured. A circular plumb 30 is enclosed within the case 10 and movable in radial direction, and the spring 20 passes through a minimum inner diameter portion 32 of a tapered hole 31 of the plumb 30 and projects upwards. A small gap exists between the spring 20 and the minimum internal diameter part 32, and when the plumb 30 is moved by impact inertia applied thereto the spring 20 can be smoothly curved about the bottom as a fulcrum on account of the gap. The plumb 20 is disposed slidably to lower surface of a plastic plate 40 fixed on the case 10. Outer circumferential edge of a semicircular member 50 of a thin metal plate is fixed to upper surface of the guide plate 40, and the member 50 covers the spring 20. A scratch 53 is applied to inner surface 52 of the member 50 by the top end of the spring 20 on account of inertia applied to the plumb 30 at impact state.