GB730951A - Improvements in or relating to ball point pens - Google Patents

Abstract

730,951. Reservoir pens. GILLEN, R. Jan. 10, 1951 [Jan. 17, 1950; May 3, 1950], Nos. 1192/50 and 10884/50. Class 146(3). In a ball-point pen a capillary conduit is open at one end to atmosphere and at the other end opens into the ink reservoir, and a plunger which closes the end of the reservoir remote from the writing point can be manually adjusted along the reservoir to cause ink to flow from the reservoir into the capillary conduit. As shown in Fig. 1, the pen barrel 1 forms the reservoir 1A the open end of which is sealed by a piston 11 adjustable along the reservoir by a screw 12. A capillary passage 5, integral with the barrel 1, is open to atmosphere at the upper end through a hole 8 in a screw cap 7, and its lower end 5A is slightly above the inlet to the ink feed passage 2 which leads to the writing ball 3. When the reservoir 1A and passage 5 are filled with ink the ink in the passage is used first, and this is then replaced by moving the plunger 11 downwardly. The opening 5A may be so small that the capillary pull of the meniscus of the ink when the passage 5 is almost exhausted will be greater than that exerted in writing and so prevent ink reaching the ball 3 and warn the writer that the plunger 11 should be depressed. In a modification (Fig. 4, not shown), the capillary conduit comprises a separate central tube having screw-threaded engagement with the plunger in the reservoir, the upper end of the tube extending beyond the plunger and serving to move the latter on being rotated. In Fig. 2 a central capillary tube 13 is secured at the lower end to a plunger 14 having screw-thread engagement with the barrel 1. When the ink in the tube 13 is used up, the tube is rotated to move down the plunger and so refill the tube. In modifications of this construction, the plunger may have purely frictional engagement with the inside of the reservoir and comprise two annular discs spaced apart by a rubber disc, and the lower end of the capillary tube may have its bore reduced, say by the insertion of a perforated plug therein, to cause cessation of ink flow to the ball when the tube is almost exhausted.