GB854313A - Improvements in or relating to writing instruments - Google Patents

Abstract

854,313. Writing instruments. KAHN Inc., D. Aug. 3, 1956 [Aug. 30, 1955], No. 23993/56. Class 146(3). A retractable writing instrument, e.g. a ball point pen, comprises a plunger 30 non- rotatably mounted in the barrel, an axially displaceable and rotatable member 40 whose axial position determines the axial position of the cartridge unit, and a spring 24 which urges the member 40 towards the plunger, the member 40 and the interior of the barrel being formed with coacting members which interengage in different axial positions depending upon their relative rotational adjustment, depression of the plunger 30 partially rotating the member 40 to effect such adjustment. The plunger 30 has at its upper end radial lugs 33 with downwardly projecting teeth 34. The member 40 has at its lower end, as shown in Fig. 1, radial lugs 42 of greater diameter than the lugs 33 and formed at their upper edges with inclined surfaces 42a. A series of longitudinally extending alternately deep and shallow grooves 52, 53 is formed in a barrel part 13, the grooves having teeth 51 adjacent to their lower ends. The upper part of the member 40 is rotatably received in a recess in the plunger 30 so that the teeth 34 can engage the inclined surfaces of the lug, 42 and the inner end of the pen unit 20 fits within a recess 41 in the member 40. The grooves 52, 53 are of such dimensions that the lugs 33 can enter all the grooves but the lugs 42 can enter the deeper grooves 52 only. In retracted position the lugs 33 are at the upper ends of the grooves 52, 53, there being one lug 33 for each groove, and the lugs 42 are, in the deep grooves 52 bearing against the opposed teeth 34, there being one lug 42 for each deep groove. When the plunger 30 is depressed, the member 40 moves downwardly and the pen point is projected ; during this movement the engagement of the teeth 34 with the inclined surfaces 42a tends to rotate the member 40 and in fact rotation takes place when the lugs 42 clear the bottoms of the grooves 52. Upon release of the plunger 30 the surfaces 42a engage the teeth 51 and such engagement under the action of the retracting spring 24 causes the parts 40 to rotate further until it abuts against the side 51a of the next tooth 51. The writing unit 20 is thus latched in projected position since the lugs 42 cannot enter the intermediate shallow grooves 53. When the plunger 30 is again depressed a similar action occurs but the lugs 42 are displaced into alignment with the deep grooves and the parts return to retracted position under the action of the spring 24. Reference has been directed by the Comptroller to Specification 748,897.