GB738740A - Improvements in and relating to reservoir writing instruments of the ball tip type - Google Patents

Abstract

738,740. Reservoir pens. BIRO SWAN, Ltd., [formerly BIRO PENS, Ltd.]. Feb. 2, 1953 [Nov. 3, 1951], No. 25762/51. Class 146(3). In order to obviate surplus ink accumulating on the lip of the ball housing in a ball-point pen, the writing unit is mounted for rotation in and relatively to the holder. Automatic rotation may be caused by forces set up in the act of writing, i.e. by the couple produced on the ball, or by some motive power connected to the writing unit. As shown in Fig. 1, the writing unit 1, comprising a capillary tube reservoir 1a and a housing 3 for a writing ball 2, is grooved at 7 to receive three balls 6 located in holes in a holder casing 4. The balls 6 are retained by a split ring 8, or an outer sleeve, and the arrangement thus comprises an antifriction journal bearing upon the writing unit which will rotate within the casing 4 during the act of writing. In Fig. 5, a flange 12 on the unit 1 bears on balls 13 retained by a shoulder in the casing 4 ; in a modification, a ball race is interposed between the shoulder and flange. To prevent the unit 1 from being pushed into the casing in the act of writing, a further antifriction bearing may be disposed towards the rear end of the unit, or, as shown in Figs. 7 and 9, a thrust bearing may be used. In Fig. 7 there is a single ball 15, located within a tripod member 16, engaging a hardened bearing 17 within the writing unit. The ball 15 could be located in a metal thrust plate backed by a rubber block so that the unit 1 can yield resiliently during writing. Fig. 9 shows another resilient mounting comprising a cone 18 on a thrust plate 19 which is urged forward by a compression spring 20, the point of the cone entering an indent in a bearing 17 in the reservoir 1a. In another form of thrust bearing for the unit 1, the holder casing 4 is open-ended to receive a cap having an axial bore within which is a spring-urged ball. In Fig. 12, the writing unit 1 is located within the casing 4 by two ball bearings 21, 22 as described above, and an end plug 23 has an axial bore through which a flexible cable 24 extends. The cable is attached at one end to the unit 1, and the other end is attached to some means for imparting rotation thereto. In another form, the writing unit extends beyond the rear end of the casing and has attached thereto a pulley adapted to be rotated by an endless cord driven .in some known manner. For drawing straight lines along a straight-edge, the writing unit is extended beyond the front of the casing so that it bears against the straight-edge, and is thus rotated within the casing. Specifications 573,747 and 706,317 are referred to.