Patent GB-936676-A (GB)
Title: Projection-retraction mechanism for writing instruments
Inventor: JOHMANN FRANK THEODORE
IPC: B43K24/08
Filed: 1960-08-19
Abstract: 936,676. Reservoir pens. F. T. JOHMANN. Aug. 19, 1960 [Sept. 21, 1959; April 14, 1960], No. 28847/60. Class 146 (3). A retractable writing instrument comprises a writing unit 20 biased towards a projected position, a hood 17 carried by the barrel and having an outer end movable relatively to the barrel, a push-button 36 longitudinally movable within the barrel, and actuating means whereby the point is alternatively concealed within the hood and projected through the hood, the actuating means being actuated upon longitudinal movement of the push-button in relation to the barrel, and also by longitudinal movement of the writing point or the hood or both in relation to the barrel. The pen barrel comprises two parts 10, 11 connected by a sleeve 12. The writing unit 20 has a flattened portion 25. A spring 28 positioned between washers 27 abutting against the sleeve 12 and portion 25, respectively, urges the writing unit outwards, and a spring 26 positioned between washer 27 abutting against the portion 25 and the hood 17 urges the hood outwards. A tubular latch member 29 is mounted on the rear end of the writing unit 20 and has radially projecting lugs 30. Two further tubular members 33, 34 having forward and rearward projecting teeth 42, 41, respectively are fixed in a sleeve 35 which is integral with the push-button 36 and is slidable within the barrel part 10. The teeth 41 are spaced from each other by alternate shallow and deep recesses. The lugs 30 of the latch member 29 are disposed between the two sets of teeth 41, 42 and normally are held in engagement with either the shallow or the deep recesses between the teeth 41, depending upon whether the writing point is in retracted or projected position, by the spring 28. A spring 37 disposed between the sleeve 12 and a washer 38 engaging the front end of the sleeve 35 urges the latter sleeve and the push-button towards their rearmost positions. The writing unit 20 is retracted from its projected position shown in Fig. 1 by the operator's either pressing the writing point against a rigid surface or pressing on the push-button 36, pressure being subsequently released in either case. Either of these operations has the effect of moving the lugs 30 out of the deep recesses and into contact with inclined edges of the teeth 42 which by a camming action partially rotate the member 29 and writing unit 20 so that on release of pressure the lugs are engaged in the shallow recesses between the teeth 41 and the writing point is then concealed within the hood 17. A second depression of either the writing point or the push-button restores the lugs 30 to the deep recesses and the writing point to projected position. The lugs 30 may be mounted on the sleeve 35 and the members 33, 34 may then be mounted on the writing unit. In a modification the member 29 is omitted and the lugs 30 are mounted on a rearward extension of the hood 17. The pushbutton 36 may be arranged at right-angles to the axis of the pen, instead of parallel thereto, and project through slots in the side wall of the barrel and the pocket clip. Instead of being slidable in relation to the barrel the hood 17 may be made of rubber or another resilient material. In the embodiment of Fig. 12 a toothed tubular member 52 similar to the member 34 is mounted in a sleeve 35<SP>11</SP> similar to the sleeve 35. A latch actuating member 59 is slidable in the member 52 and has ears 61 which engage grooves 55 in the latter member and which terminate at their rear ends in rearward directed teeth. A cylindrical element 58 having an annular groove 57 is slidable in the member 59 and carries a ball 56 in the groove 57. The rear end of the writing unit 20 abuts against the front end of the latch actuating member 59 and is held in engagement therewith by a spring 26. A spring 63 urges the element 58 forwards into a position where the ball 56 engages either a deep or a shallow recess between the teeth of the member 52. The longitudinal position in the barrel of the member 59, and therefore of the writing unit 20, is determined by the engagement with the-ball 56 of one of the teeth formed on the ears 61. Projection and retraction of the writing unit are effected in the same way as in the embodiment of Fig. 1, the teeth of the member 59 lifting the ball 56 out of the recess between the teeth of the member 52 in which it was located and causing it to roll around the groove 57 so that when pressure is released the ball engages the adjacent recess between the teeth of the member 52. Specifications 792,185 and 876,206 are referred to.