GB944600A - Improvements in and relating to reservoirs of writing and other dispensing instruments - Google Patents

Abstract

944,600. Reservoir pens. I.R.C. Ltd. July 11, 1961 [July 30, 1960], No. 26625/61. Heading B6P. [Also in Divisions A5 and B2] A ball-point pen reservoir is of the kind having sealing means for a vented bore occupied by a liquid column, the sealing means comprising a solid follower at the rear end of the column, the follower being a sliding fit in the bore so as to move along it as the liquid is discharged from the reservoir. As shown, the reservoir 10, Fig. 1, contains a column of liquid 11 sealed by a follower 12. The follower 12 which may be formed of two moulded parts has a reduced diameter portion 13 forming an annular gas chamber 14 between portions 15, 16 having sealing regions d 1 , d 4 containing the reservoir liquid 11 and sealing liquid 19 respectively. A reduced diameter portion 18 provides a capillary expansion duct 17 communicating with the gas chamber 14. The front end 20 of the follower is domed or coned to obviate air being trapped between the follower and the liquid upon introduction of the follower. The trapped air in the chamber 14 may contract so that the expansion duct 17 is occupied by the sealing liquid, Fig. 2 (not shown) or the duct is only partly filled with sealing liquid, Fig. 3 (not shown). Slots 21, Fig. 1, of capillary size radiating from a hole 22 form a reservoir for the liquid 19. In a modification, Fig. 4 (not shown), the portion 18 is tapered, thus dispensing with a step at the sealing region of portion 16, Fig. 1. In a modification the expansion duct 17, Fig. 5, is formed by flutes 23 formed longitudinally of the part 18 leading to the gas chamber 14. In another embodiment, Fig. 6 (not shown), the duct 17 is formed by a capillary bore 24 connecting the chamber 14 with the sealing liquid reservoir 21, 21. Instead of the expansion duct 17 being directed outwards as described with reference to Figs. 1 to 6 the duct may be directed inwards as shown in Fig. 7, the duct 17a in this case being annular and surrounding a reduced portion 18a of the follower so as to communicate between the chamber 14 and the portion 15. The portion 15 has a corner at the reduction in cross-section to the portion 18a to anchor the meniscus of the liquid occupying the sealing region dl. In another embodiment, Fig. 8 (not shown), similar to Fig. 5, the follower is made, e.g. by injection moulding in two parts secured together by adhesive. In another embodiment, Fig. 9 (not shown), the expansion duct is a bore 24c leading from the chamber 14 to the front face of the portion 15c.