GB882447A - Improvements in writing instruments - Google Patents

Abstract

882,447. Reservoir pens. SCRlPTO Inc. Jan. 16, 1959 [June 5, 1958], No. 1646/59. Class 146(3) In a retractable writing instrument having a writing unit 14, the operating mechanism includes a plunger 26, a latch member 28 shaped for displacement within the barrel upon depression of the plunger, and a toggle member 30 disposed between the plunger and the latch member and having the forward and rearward ends thereof pivoted on the latch member and plunger respectively. The plunger 26, toggle 30 and latch member 28 are moulded as a unit from a plastic material and are joined by waisted sections 32, 34 forming flexible couplings. The plunger and latch member are rectangular in cross-section and are slidable in a rectangular bore 20 at the rear end of the barrel, the front end of the latch member abutting the rear end of the unit 14 which is spring-biased into contact therewith. The latch member has laterally extending arms 38, 40 which co-operate with internal shoulders 22, 24 on the barrel and lateral fulcrum points 42, 44. In retracted position of the writing unit, Fig. 1, the arm 40 engages the shoulder 24 and the rearward bias of the writing unit 14 acting on the forward end of the latch member holds the fulcrum point 44 in engagement with one side of the bore 20. When the plunger is depressed from this position the latch member is carried forwards and by reason of the angular transmission of pressure thereto by the toggle 30 tends to rock in an anti-. clockwise direction about the fulcrum point 44 so that when the arm 38 reaches a position laterally adjacent to the shoulder 22 it latches thereunder. When pressure on the plunger is released the parts assume the Fig. 3 position in which the writing unit is projected. A second depression and release of the plunger restores the parts to the Fig. 1 position. The plunger has lateral abutments 36 to limit the distance it can be pressed into the barrel. In a modification the toggle 30 may be a separate piece from the plunger and latch member and may be either secured thereto by pivot pins or engaged for pivoting in recesses in the plunger and latch member. In the latter construction the plunger is spring-biased downwards. Specification 804,903 is referred to.