GB633821A - Improvements in reservoir writing instruments - Google Patents

Abstract

633,821. Reservoir pens. MARTIN, H. G. April 19, 1945, No. 9785. [Class 146 (iii)] In a reservoir pen with a ball point the walls of the ink-containing sac are at least in part deformable and resilient pressure is applied to the deformable part, the maximum value of which is such that the ink pressure is no greater than and preferably less than the capillary pressure in the gap between the ball and its housing. In one form, Fig. 1, the reservoir is constituted by a rubber sac 5 preferably enclosed in a metal sheath 15 by which it is secured to the point section 16. A spring 6 extends between a washer 7 bearing against the sac and a plug 8 slidable by means of a pin-andslot connection 9, 10 in the end of the barrel. To apply pressure, the cap 11 is removed from the point end of the barrel 1 and screwed into the other end so that an inwardly projecting part 12.thereon moves the plug 8 inwardly to compress the spring 6. In another form, Fig. 3, the sac 17 encircles a tube 18 connected at one end to the point section and open at the other end. Pressure is exerted on the reservoir by a ring 23 slidable thereover and subject to the action of a spring 24 which is compressed when the pen is assembled. Holes 22 in the end of the tube 18 adjacent to the point allow the ink to pass to the nib section as the sac is collapsed. The spring 24 may be compressed by means of the cap or by attaching to its outer end a weight so that pressure is exerted only when the pen is in writing position. The sac may consist of a cylinder with a flexible diaphragm or of a cylinder of light metal corrugated throughout its length or at its rear end only. According to the Provisional Specification pressure may be applied to the ink by compressed air or a spring-pressed plunger. Ink. The ink employed may comprise an oleaginous solvent e.g. olein, castor oil, ricinoleic acid or combinations thereof, a thickener such as colophony, and a dye such as aniline dye, or according to the Provisional Specification may be as described in Specification 629,226. Specifications 571,698, 573,747, 633,879 and 633,880 also are referred to.