GB410662A - Improvements in self-propelling lead pencils - Google Patents

Abstract

410,662. Pencil holders. JOHNSSEN, H., 133, Wilhelm Spaethstrasse, Nuremberg, Germany. Sept. 8, 1933, No. 24891. [Class 146 (iii).] A pencil holder is provided with a spring- pressed pusher having a double rack cooperating with a detent which, on operation, permits the spring to feed the pusher and lead forward one step through a point section normally spring-pressed to forward position, but, on application of axial force, slidable relatively to the casing to enable the lead to be pushed rearwardly into protected position, the pusher being forced against the action of its spring past the detent. The pusher 6 is slidable in a bore 3 in the rear end of the casing 1 and has teeth on two edges, the two sets of teeth being relatively offset and having front faces arranged at right angles to the axis of the pusher and inclined rear faces. The detent 9, having a rectangular opening of a width to enable the pusher to slide therein and of a length slightly less than the overall height of the teeth, is carried by a slide 5 movable in a transverse bore in the casing. A spring 8 acts between a shoulder 3<a> in the casing and a shoulder 8<a> on pusher, so that, on moving the slide 5 from one extreme position to the other, the pusher is permitted to move forward by the amount of staggering between the sets of teeth. The extension 7 of the pusher passes into the point-section which is formed of a tapered portion 12 screwing into the casing, a plug 17 screwing into the portion 12 and supporting a spring 16, and a slidable point-element 18 split at the forward end to grip the lead and normally pressed forward by the spring 16 against a stop shoulder. To withdraw the lead into the casing, it is pushed against a hard surface, and the rear inclined faces of the rack teeth actuate the detent. If the projecting length of lead is so worn that it is too short to press the pusher inwards a sufficient amount, the pressure is received by the point-element 15 which recedes against the action of the spring 16 to permit the pusher to be forced past the detent, and is returned to normal position when the pressure is released.