GB719302A - Improvements in and relating to reservoir writing instruments - Google Patents

Abstract

719,302. Reservoir pens. BIRO SWAN Ltd., [formerly BIRO PENS, Ltd.] May 12, 1952 [May 25, 1951], No. 12261/51. Class 146(3) In a ball-point pen the reservoir inner surface is fluted longitudinally throughout a major part thereof along which the ink meniscus travels. As shown in Fig. 1, the body 1, constituting the reservoir, is fluted internally along its length, these flutes 8 preferably being tapered to facilitate manufacture by moulding, although they could be parallel when formed by extrusion. A writing extremity 3 housing ball 4 is fitted at one end, and a closure plug 6 having a small hole 7 therethrough is fitted at the other end of the body. The cross-section of the reservoir may be star-section, Fig. 4, the flutes 11 tapering towards their r extremities, which are dispersed on a circle of about 5 mm. diameter and are provided with a radius of about 0.25 mm.: the internal bore 2 is from 2.5 to 3 mm. diameter. in Fig. 7 the flutes 15 have almost a complete circular form, their diameter being less than 2 mm., the throats 17 about 0.5 mm. wide, and their extremities disposed on a circle 4 mm. in diameter. In the case of a reservoir which is tapered along its length, the above dimensions are those at the larger end of the fluted part. Various other cross. sections are shown and described, the purpose of which is to increase the ink capacity of the reservoir without the risk of ink leakage due to breakage of the meniscus. A viscous plug may rest on and follow the rear end of the column of ink. Specifications 571,698, 573,747, 609,817, 685,916, 691,469 and 706,317 are referred to.