GB876206A - Protraction-retraction mechanism for writing instruments - Google Patents

Abstract

876,206. Reservoir pens. JOHMANN, F. T. Aug. 15, 1958, No. 26301/58 Class 146(3). A retractable ball-point pen comprises a cartridge unit 22, a slidable sleeve 17, both urged outwardly by springs 31 and 21, respectively, a latch mechanism having two toothed members 35, 36 mounted in the outer casing, and a cylindrical latch element 27 engaging the inner end of the cartridge unit and having projections 33 adapted to engage the teeth. The teeth 37, 40 are offset with respect to each other and deep slots 38 are arranged between the teeth 40. On depressing the ball-point 25 and sleeve against the surface 41 the projections are lifted clear of the slots 38 and strike the teeth 37, causing the cartridge unit to rotate slightly. On lifting the pen clear of the surface, the cartridge unit and sleeve are returned under the action of their respective springs, the projections 33 engaging the teeth 40 to hold the unit in its retracted position. In a modification the members 35, 36 are rigidly connected by a tube located in an annular groove in the casing and free to rotate therein. In another embodiment the two series of teeth are formed in opposite ends of a single member 45 and the latch element provided with two series of projections 33<SP>1</SP>, 33<SP>11</SP>. The two series of teeth or projections are offset with respect to each other, and the member 45 and latch element made from plastic material. The latch element is slotted as at 44 to facilitate the passing of the projections 33<SP>11</SP> through the central bore in the member 45, when the latch element is assembled in the casing..