GB269691A - Improvements in or relating to apparatus for recording speed or motion - Google Patents

Abstract

269,691. Bruhn, F. W. G. Jan. 27, 1926. Temporary recorders.-In order that the necessity for changing the record chart of a speed-indicator &c. periodically mav be avoided, the marking point is arranged to mark a sheet or dial from which the record is subsequently effaced automatically. The recording device is of the type in which a disc c, Fig. 3, is backed by a disc d of iron foil or other material. The disc d is dark in colour and coated with a sticky substance, so that a record is made when the discs c, d, are pressed together by a marking point f. The point f is carried by a rack bar f<1>, Fig. 1, which is positioned by a pinion g on the spindle of the speed indicating hand. The previously made record is effaced automatically just before reaching the marking point by separating the discs c, d. In the arrangement shown in Fig. 3 this separation is effected by magnets h<1> which draw the iron foil d away from the disc c. The discs may be separated by a bar passing between them, or by making the foil disc d slightly longer than the other, and causing a fixed projection to make a loop in it just in front of the marking point. The marking pin may be of the kind which produces an oxidizing line on a sheet, in which case the record is effaced by a chemically treated pad. Figs. 5 and b show an arrangement in which the marking point is brought into contact with the foil by the jolting of the vehicle to produce an " in-motion " instead of a speed record. The effacing magnet h, which carries the marking point f on one of its arms, is mounted on a pivot p and acted upon by a spring r so that the jolting of the vehicle will bring the marking point against the record foils. In this arrangement a number of concentric record foils are provided corresponding for instance to different days of the week. The marker is moved from one circle to another by a stepped clock-driven cam l which acts upon a slide n to which the magnet h is pivoted. The record may be in the form of a spiral instead of a number of concentric circles. Fig. 7 illustrates means for maintaining the rotation of the recording chart in the event of the vehicle drive breaking down. The normal drive is by means of gears t - - w and the auxiliary drive comprises a weighted lever z which is pivoted at y and is adapted, when jolted by the movement of the vehicle, to drive the gear v through a pawl and ratchet 22. A clutch 23 is provided and the arrangement is such that the normal drive from the gear t is faster than that from the lever z. The lever z may be held stationary while the speedometer hand s is in movement by a pivoted latch 24 which is set by pins 26 on a gear 25<1> engaged by a gear 25 on the spindle of the speedometer hand. In place of the lever z, a spring motor may be arranged to actuate the auxiliary drive.