US1746474A - Mechanical pencil - Google Patents

Description

E. G. E. HOGNER I 'Feb; 11, 1930.

MECHANICAL PENCIL Filed Jan. 15, 1929 Patented Feb. 11, 19 30 UNITED STATES PATENT OFFICE I um GUSTAF EVALD noeivnn, or srooKI-iomv SWEDEN MECHANICAL PENCIL, Application filed January 15, 1929. Serial No. 332,576.

This invention relates to mechanical pencils and more particularly to an improved step by step feeding mechanism for the lead or crayon in such pencils.

Thechief object of the invention is to provide improved means of this kind in which the pusher is automatically released at the end of its advancing movement after a lead hasbeen entirely pushed out or consumed and afiter returning to its starting position is again brought into operative engagement withthe step by step feeding mechanism.

The invention consists, chiefly, in a step by step feeding mechanism for the lead or crayon, comprising a stationary and a slidable rack, means for reciprocating said slidable rack, a slide, pawls carried by said slide and normally engaging said racks, a pusher connected to the slide, a control-member for lindrical shape is provided having a vertical. series of teeth or a rack 8 cut in its inner wall. A second inner sleeve 4 of semicircular cylindric shape is also provided in the outer sleeve 1 and has likewise a vertical series of teeth or a rack 5cut in its inner side-wall. The sleeves 2 and 4 together form a cylinder and the racks 3 and 5 which only extend along a part of the length of the respective sleeves are placed diametrically opposite to each other (Fig. 5). The sleeve 2is detachably attached to the sleeve 1 by means of a bayonet joint comprising a pin6 engaging a groove 7 while the sleeve 4 is slidable in the saidouter sleeve 1 and thus also slidable in relation to the sleeve 2. i a

The stationary inner sleeve 2 is provided at one end with a bottom 8, from which a tube 9 having an annular flange 10 extends upsaid pawls movably journalled in said slide, wards in the centre of the pencil. The tube and a stop adapted to operate said control- 9 serves as a stop member for releasing the .member in the lowermost position of the feed mechanism in its lowermost posit-ion.

slide so as to release the pawls from engage- In its other end the sleeve 2 carries a cylinment with the racks. i dricstop or end member 11 secured to it by In the accompanying drawings one embodmeans of screws 8? or the like. The slidable iment of my invention is shown. inner sleeve 4 has at its lower end a bottom Fig. 1 shows an improved pencil accord 12 containing an opening, which fits onthe ing to my invention, partly in longitudinal tube 9 but cannot pass the flange 10. The section. upper end of the said sleeve 4 is formed with Fig. 2 shows .a portion of the pencil in a projection 13 extending laterally and havlongitudinal section at right angles to the ing an annular flange 14 on its upper side. A sectionin Fig. 1. screw 15 extendsthrough a hole in the said Fig.3 shows a portion of the pencil in the projection 13 and is screwed into the stop or same longitudinal section as shown in Fig. 1 end member 11. The head of the screw 15 to illustrate the position of the parts immeforms a stop for the sleeve 4 to check its updiately after the pusher has been released. ward movement. A spring 16 is provided Figs. 4 and 5 are cross-sections on a larger between the bottoms8 and 12 and presses the scale on the lines IV-IV and VV in sleeve 4 upwards, thus causing the projection Fig. 1. i 13 normally to rest against the head of the Fig. 6 is longitudinal section of a porsaid screw 15. Longitudinal recesses 17 are tion of the pencil illustrating a modified emmade in the outer wall of the sleeve 4 to rebodiment of the pawls and their control memduce its friction when it slides in the sleeve ber. a i 1. On the annular flange 14 a holder 18 for Fig. 7 illustrates the position'of the parts an eraser 19. isprovided which is covered by shown in Fig.6 immediately after the pusher a removable cap 20 rests upon the prohas been released. jection 13 by means of a shoulder.

Referring now to Figs. 1 to 5 of the draw- In the cylindric channel'formed between ings 1. indicates an outer sleeve of well-known the sleeves 2 and 4 a slide 21 is provided havtype for mechanical pencils. In this outer ing a pusher-22 secured thereto. The said sleeve 1 an inner sleeve 2 of semicircular cypusher is placed in the axis of the pencil and is guided by the tube 9. The slide 21 has a recess or groove 23 extending through it and forming two longitudinal openings in the periphery thereof diametrically opposite to each other. In the said recess 23 two pawls 24 and 24 rotatable on pins 25 are provided, said pawls projecting through the said opposite openings and engaging the racks 3 and 5, respectively. A pin 26 (Fig. 5) engaging a groove 27 in the inner wall of the sleeve2'is provided on the outer side of the [slide 21 to guide the latter in such manner that the pawls 24 and 24 are always right in'front of the racks 3 and 5. The pawls 24 and 24 are connected by a spring 28 tending to withdraw them from their engagement with the racks 3 and 5. The inward movement of the pawls 24 and 24" is limited by pins 29.

A control-member or rod 30 is slidably journalled in the slide 21 between the pawls 24 and 24". On the upper portion of the said control-member which projects above the slide 21 a collar 31 is fixed limiting the movement of the said control-member downwards in relation to the slide 21. The control member 30 is forked in its lower portion (Fig. 2) and the prongs thereof enclose the spring 28 and project downwards below the slide 21 on both sides of the pusher 22. The upper edges of the said prongs are checked by shoulders 32 of the slide 21 when the controlanember is moved upwards, the movement of the latter thus being limited upwards as well as downwards. Two springs 33 are secured to the control-member and engage the back sides of the pawls 24 and 24 in the lowest position of the control-member to press them towards the racks 3 and 5 against the action of the spring 28. Immediately above the points in which the springs 33 engage the pawls 24 and 24* in the said lowest position (Fig. l) of the control-member 30 the said pawls are provided with steep noses or shoulders 34. A spiral spring 35 is provided between the slide 21 and the bottom 12 to press the said slideupwards in the direction from the point of the pencil. One or more spring-pressed buffers 36 may be provided in the projection 11 to receive the shock when the slide is returned by the spring 35. The leads or crayons to be fed are contained in a suitable magazine 37, for instance, of the revolving type. V

The device now described works as follows:

To feed the lead the cap 20'is pressed downwards pushing in its turnthe sleeve 4 in the same direction until the bottom 12 is checked by the flange 10 or the projection 13 is stopped by the stop or end member 11 and the upper edges of the sleeves. 1 and 2. The stroke of the sleeve 4 is substantially equal to the pitch of the racks 3 and 5. hen the sleeve 4 is thus pushed downwards the slide 21 is also pushed downwards by the pawl 24 engaging the rack 5- The pusher 22 which is secured to the said slide 21 is consequently also pushed down the same distance and feeds in its turn the lead from the magazine 37 before it. At this movement the other pawl 24 drags over the adjacent tooth of the rack 3 compressing the corresponding spring 33 and is caused by the said spring to engage the next tooth after the advancing movement has been completed. The cap 20 is now released whereupon the spring 16 restores the sleeve 4 as well as the cap 20 to their starting positions. During this movement the slide 21 is kept in position in relation to the sleeve 2 by the pawl 24 engaging the rack 3 while the pawl 24 drags over the rack 5 until it engages the next tooth when the return movement is finished. By pressing and releasing the cap 20 in this manner the lead before the pusher is fed successively until it has been entirely consumed. The slide 21 then reaches the lowest point of its path and the prongs of the forked portion of the control-member 30 are checked by the upper end of the tube 9. The control-member 30 is thereby pushed upwards in relation to the slide 21 until the two springs 33 pass the projections 34 on the pawls 24 and 24 The spring 28 now withdraws the pawls 24, 24 from the racks 3 and 5 respectively, the different parts thereafter having the positions shown in Fig. 3. The slide 21 thus released is now restored by the spring 35 to its starting position in the uppermost portion of the pencil body. At the end of this movement the upper portion of the control-member 30 is checked by the projection 11 and the said control-member is pushed back in relation to the slide 21 so that the springs 33 pass by the projections 34 and again bring the pawls 24, 24 to engage the racks 3 and 5. The control-member 30 is then kept in its normal position by springs 33 engaging the slanting or concave back sides of the pawls 24, 24 below the projections 34. Now the feeding can be started again as described above.

In the modified embodiment shown in Figs. (5 and 7 a wedge-shaped portion 38 of the control-member 3O converging upwards in the direction from the point of the pencil is used for releasing the pawls 24, 24. When the prongs of the control-member 30 are checked by the tube 9 at the lowest end of the path of the slide 21 the wedge 38 is pressed upwards, thus pushing the lower ends of the pawls 24, 24 apart. The upper portions of the said pawls are thereby withdrawn from their engagement with the racks 3 and 5 and release the slide 21 which is restored to its starting position by the spring 35 as described above.

To put the mechanism apart, for instance when the magazine 37 is to be filled the bayonet joint 6, 7 is opened and the sleeves 2 and 4 as wellas the magazine are drawn out from the outer sleeve 1. V

The magazine 37 may be of any suitable construction and forms no part of this invention. The mechanism above described can, if desired, be used Without any magazine whatever. In this latter case the leads are placed by hand before the pusher and then successively fed, as describe What I claim is:

1. In a mechanical pencil, a step by step feeding mechanism for the lead or crayon,

comprising a stationary and a slidable rack,

a means for reciprocating said slidable rack, a slide, pawls carried by said slide and normally engaging said racks, a pusher connected to the slide, a control-member for said pawls movably journalled in the slide, and a stop member adapted to operate said control,- member in the lowermost position of the slide so as to release the pawls fromjengagement with the racks.

2. Ina mechanical pencil, a step by step feedingmechanism for the lead or crayon, comprising a stationary and a slidable rack, means for reciprocating said slidable rack, a slide, pawls carried by said slide and nor-.

mally engaging said racks, a pusher carried by said slide, a control member for said pawls movably journalled in the slide, a stop member adapted to operate said control member in the lowermost position of the slide so as to release the pawls from engagement with the racks, and a spring for returning the slide to its uppermost position.

3. In a mechanical pencil, a step by step feeding mechanism for the lead or crayon, comprising a stationary and a slidable rack, means for reciprocating said slidable rack, a slide, pawls carried by said slide and normally engaging said racks, a pusher connected to the slide, a control-member for said pawls movably journalled in the slide, and

stop members adapted to operate said control-member in the end positions of the slide so as to bring the awls in and out of engagement with the rac rs. 4. In a mechanical pencil, a step by step feeding mechanism for the lead or crayon, comprising a stationary and a slidable rack, means for reciprocating said slidable rack, a slide between said racks, pawls carried by 5 said slide and normally engaging said racks, a pusher conencted to the slide, a control rod movably journalled in the slide, springs carried by said control rod and adapted to operate the pawls, and stop members adapted to operate said control rod in the end positions of the slide so as to bring the awls in and out of engagement with the rac s.

In testimony whereof I have signed my name. EINAR GUSTAF EVALD accuse.

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