GB837676A - Writing instruments - Google Patents

Abstract

837,676. Reservoir pens. PAPER MATE OF PUERTO RICO Inc. Dec. 19, 1956 [Dec. 27, 1955], No. 38668/56. Class 146(3) A writing in- FIG.2. FIG.7. strument assembly adapted to receive a retractable writing unit, comprises a retracting mechanism having a plunger provided with inclined cam faces for moving the writing unit between a retracted and projected writing position, a n d a non-rotatable cam follower which engages the inner end of the writing unit when in position, the cam follower having a pair of surfaces which can engage inclined longitudinally displaced stop surfaces in a member secured in the instrument barrel, whereby operation of the plunger will result in engagement of one surface of the cam follower with one stop surface, whereupon the inclination of the stop surface moves the cam surface into a position where it will be engaged by the other cam surface on the plunger at the next operation of the plunger. As shown, a ballpoint pen unit 11 is slidable in a barrel part 15 encased in a sleeve 16, the unit being urged into retracted position by a spring, not shown. A cam follower 17 is retained in the barrel part 15 by a bush 20 fitted into the barrel part 15. An operating plunger 24 having a shank 26 slidable but non-rotatable in the bush 20 is pressed rearwardly by a spring 30. The shank 26 has a retracting cam face 27 and a projecting cam face 28. The bush 20 has a bore 29 provided with oppositely inclined stop shoulders 38 and 40 which determine the retracted and projected positions of the unit 11. The cam follower 17 has inclined cam surfaces 52, 54 which cooperate with the stop shoulders 40, 38 respectively. The cam follower 17 has a base retained against rotation by a notch 70 which receives a key 72 secured to the barrel part 15. On operation, the plunger 24 is depressed to cause retraction of the unit 11 from its projected position as shown in Fig. 2. The face 27 contacts the rounded end 50 of the cam follower and urges the cam follower and writing unit downwards, such that the cam surface 52 clears the shoulder 40, thereby allowing the cam follower to tilt to the right until the end 50 engages a recess 34 in bush 20. On release of the plunger 24, the cam follower is pressed upwardly by a spring, not shown, until the surface 54 on the cam surface engages the shoulder 38 as shown in Fig. 7, thereby retaining the unit in retracted position. Further depression and release of the plunger 24 causes the parts to return to the position shown in Fig. 2 in which the unit 11 is retained in projected position. Specification 757,115 is referred to.