GB259675A - Improvements in self-filling stylographic pens - Google Patents

Abstract

259,675. Sweetser, G. July 15, 1925. Self-filling stylograph pens; air-supply. - In a self-filling stylograph pen of the kind in which the piston is adapted to form a vacuum behind it during the inward stroke and to co-operate with a recess in the inner wall of the barrel to enable ink to be drawn into the barrel round the piston, an airvent, which is arranged to be closed by the finger during filling, is provided through the piston-rod. The piston-rod 5, which carries the spring needle 10, is hollow and is provided with holes 7, 8, opening respectively into the atmosphere and the interior of the barrel near the front end. During filling, the hole 7 is covered by the finger to prevent the induction of air. The piston-rod 5 slides in a stuffing-box consisting of washers 3 and a cork or other packing 4 housed in a wider part of the barrel, the upper washer screwing into place to facilitate removal of the parts. A flexible sleeve 14, of sufficient diameter to leave a clearance between it and the piston-rod, may be secured to the rod in order to prevent any ink, which is trapped in the front end of the barrel and which is unable to escape sufficiently rapidly through the opening for the needle, from being forced into the air tube. The Provisional Specification also describes a modification in which the front end of the piston-rod is provided with a sleeve adapted to be moved by a spring to cover the air-hole, but normally held in position to leave the hole uncovered. In another modification, a rigid sleeve may be fixed to the piston-rod, the thin film of ink between the sleeve and rod being sufficient to prevent the induction of air during filling, but leaking sufficiently for equalizing the pressure during use. Specification 13768/05 is referred to.