US2138233A - Mechanical pencil - Google Patents

Description

Nov. 29, 1938.

P. s. HAUTQN MECHANICAL PENCIL Fiied sept. 15, 1956 Patented Nov. 29, 1938 i UNITED STATES PATENir OFFICE y HTSG..

Appllctln N0. 1 ,s

'I'his invention relates to new and useful improvements in mechanical pencils, especially oi the type capable of utilizing a comparatively long lead and wherein the relative motion of exterior casing or shell parts connected to certain relatively movable !eed mechanism parts causes the lead to travel back and forth.

An object of the invention is to provide a simplified and eiilcient construction in which the relative position or the paris is positively maintained so that free and accurate movement is achieved.

A further object is to provide a simple and eiiicient driving connection between an exterior 5 part and a feed mechanism part.

A still further object is to provide a simpliiied braking device designed to take-up any wear or loos'eness in the rotating parts which may develop after long usage. Y comprehensively stated the invention. which has some features in common with co-pending application of Paul S. Hauton, Serial Number 30,968, iiled July 12, 1935, comprises relatively movable exterior parts enclosing lead feed mechanism including a helix, the latter being relatively -rotatable with respect to an exterior part and having a driving connection with'another part, with means for maintaining its axial alinernent in the exterior parts.

More specifically stated, one feature of the invention resides in a driving sleeve, one end of which surrounds and is locked to the upper turns of a helix with its upper end enlarged and extending beyond one of the exterior parts to afford a support for manually operable eraser sleeveor ferrule forming an exterior part, the ared part `of the driving sleeve;A conveniently resting on a ilanged bearing member fitted tightly into the top of one of the exterior parts to center the mecha- 0 nism with a simplied brake element held in one of the exterior parts and bearing against the driving sleeve so that too free movement of the rotating parts is prevented and the pressure against the lead during writing will not turn the helix and permit the lead to push back into the point While one embodiment of the invention is illustrated in the accompanying drawing, it is to be 50 understood that this embodiment merely serves as an illustration of the underlying principles of the invention so that they may be readily comprehended by those skilled in the art and is not intended as limiting the invention to the specific 55 form disclosed therein.

In said drawing: y

Figure 1 is an elevation of the pencil, partly fragnileitary.

Fig4 e 2 is an enlarged detail sectional view of the pencil. 5

Figure 3 is a horizontal cross section of the pencil taken on the line 3-3 of Figure'2.

Figure 4 is a horizontal cross section on the line l--J, of Figure 2.

Figure 5 isa perspective view of the eraser and 10 holder.

Figure 6 is a perspective view of the outer sleeve which is turned to advance the lead.

Figure '7 is a perspective view of the improved driving sleeve. 15

Figure 8 is a perspective view of the improved bearing member.

Figure 9 is a perspective view of the tip.

Figure 10 is a perspective view ofthe lock washer. 20

Figure 11 is a perspective view of the lead gripping tube. Figure 12 is a perspective view of the ejector pin.

Figure 13 is a perspective view of the tension 25 brake member.

Figure 14 is a perspective view of the main barrel.

Figure 15 is a perspective View of the propeller spiral. Figure 16 is a perspective view of the lead guide tube.

Continuing now by way of a more .detailed description, the reduced end or shank of a lead guide tipA I0 is press fitted into the lower end of 35 the exterior part II, the lower end of said exterior part being thickened to afford an axial bore to receive the reduced end or shank of the lead guide tip. The lead guide tip ID is locked to the lower end of a slotted guide tube by means of oppositely disposed inwardly projecting lugs Il and I4', preferablyrformed by offsetting opposite portions of the upstanding sleeve of the lead guide tip IIJ, the oiiset lug I4 engaging an opening Il" in the slotted tube. A helix I 5 pref- 45 erably consisting of a coiled strip of relatively stiff material bears at its upper end against a lock washer I6 centered on the upper end of the slotted feed I2 and which'is held in place by outturned corners I'I of the slotted guide tube. The 50 helix is prevented from moving longitudinally in one direction by its upper end abutting against the lock washer which in turn, is held relatively stationary with respect to the exterior-part 'by the slotted tube and 'tip arrangement heretofore 55 described and in the opposite direction by a driving sleeve secured to the helix I5 and cooperating with a bearing secured to the upper end of the exterior part II, as will be more fully described hereinafter. A lead grip sleeve I8 slides in the slotted tube I2 and has a laterally disposed offset lug or wing I9 projecting through the slot of the slotted tube and extending between the turns of the helix I5. A writing lead 20 is frictionally gripped within one end of the lead grip sleeve I8 `and is backed by an ejector pin 2| adapted to slide back and forth in the lead grip sleeve and eject the lead from the sleeve at one end of its stroke. An offset lug or wing 22 on the ejector pin 2| projects through a slot 22 in the lead grip sleeve I8 and has its movement limited thereby. The wing 22 also extends through the slot in the slotted tube and lies between the turns of the propeller helix. In its normal operating position, the ejector pin lug is spaced two helix turns away from the lug of the lead grip sleeve.

This spacing permits a satisfactory thread pitch and enables the ejector pin to move a sufficient distance so that its lower end will project beyond the lead grip sleeve to eject any of the writing lead which may remain in the lead grip sleeve at the end of the stroke of the sleeve and yet afford a long lead receiving space Within the lead grip sleeve when the ejector pin lug is backed up to its normal operating position.

Some of the upper turns of the helix I5 are tightly gripped by the lower end 23 of a driving sleeve, the upper end of which is flared outwardly as at 24 with longitudinally disposed oifest bosses 25 at its upper end which flexibly engage with the inner surface of the manually operable rotatable sleeve 2'6 which also acts as an eraser holder. The helix I5 is locked to the driving sleeve by an offset 26' locking with an opening I5 formed in the helix I5. A bearing B has a plurality of alternately staggered dependent ears 2'I and 21' and an outwardly extending flange 28. The ears 21 normally tend to spring outwardly and engage the inner surface of the exterior pencil part I-I, to securely hold the bearing in the upper end of said exterior part with the flange 28 overlying the upper circumferential edge of said exterior part. Each of the ears 21 arranged between each pair of ears 21, taper inwardly to seat the tapered portion 24 of the rotatable driving sleeve and to afford a three point bearing therefor the bearing B effectively centering the driving sleeve and its associated parts including the helix I5 with respect to the exterior member part Il. The manually operable sleeve fitted on the enlarged end of the driving sleeve also serves as an eraser holder and is conveniently provided with an inturned flange 29 which acts as a stop member for the bottom of the cup 30, which receives and holds the eraser 3I. Disposed within the exterior part or barrel Il and surrounding' the lower end of the driving sleeve 23 is a tension brake element 32, preferably of stiff spring metal, the body portion thereof firmly gripping the drive sleeve and so shaped that its outward spring holds the brake element rmly in the exterior part II. Conveniently, the brake element is shaped to provide a boss 33 and a projecting flap 34. The boss 33 and projecting flap 34 being adapted to spring outwardly against the inside walls of the exteriorpart II with the free end pressing inwardly to afford a drag on the driving sleeve.

From the foregoing, it will be noted that the exterior part I I, and the lead guide tip I0, flanged bearing niember and brake element 32, form relatively stationary parts with the slotted guide tube of the lead feed mechanism. The helix,

driving sleeve 23 and the eraser sleeve or ferrule rotate relatively to these parts and move the lead grip sleeve and ejector pin back and forth. 'I'he ejector pin lug is normally spaced from the lug of the lead grip sleeve until the lead grip sleeve lug clearsthe lower end of the helix at the end of its stroke. The ejector pin lug then advances toward the lead grip sleeve lug. In order that the lead grip sleeve may be held in ejecting position until the ejector pin lug has moved away from the lead grip sleeve lug the desired distance, the material at the edge of the slotted tube may be swedged to form a friction or spring catch or offset 35. 'I'he lug of the lead grip sleeve is held by this catch until the ejector pin lug strikes the upper end of the lead grip sleeve slot. Further rotation of the helix thereupon disengages the grip sleeve lug from the catch 35 and permits the lug to enter the helix.

From the foregoing, it will be observed that the assembly and construction of the pencil is very much simplified with the parts definitely maintained in proper operative position.

It is claimed:

1. A mechanical pencil which comprises an exterior part, a propeller helix therein, a driving sleeve surrounding a portion of the helix and tightly fitted thereto and a tension brake member within the exterior part and bearing outwardly on the wall of the exterior part and inwardly against the outer wall of the driving sleeve.

2. A mechanical pencil which comprises an exterior part. a propeller spiral consisting of a loosely wound flat, strip therein, a driving sleeve surrounding the upper portion of the spiral and drivingly engaging therewith, a spring tension brake member within the exterior part and bearing outwardly on the wall of the exterior part and inwardly with spring action against the outer wall of the drive sleeve, a bearing member disposed in the top of the exterior part, and having a flange resting on top of the exterior part, the inner portion of the bearing member fitting tightly against the inner wall of the exterior part and against the outer wall of the driving sleeve to center the rotating parts.

3. A mechanical pencil comprising a plurality of relatively movable exterior parts, a plurality of feed mechanism parts enclosed Within said exterior parts, a brake element adapted to be compressed within one of the exterior parts and to spring outwardly against said part, and having an arcuate part adapted to be sprung outwardly for insertion of one of the lead feeding parts, the arcuate part normally tending to spring inward- 1y against said feed mechanism part and retard its rotation.

4. A spring braking element for mechanical pencils having oppositely disposed relatively flat outer surfaces with a free end, curved on its inner face.

5. A brake element for mechanical pencils, consisting of a strip of metal having oppositely disposed bearing surfaces adapted to spring outwardly with an arcuate free end adapted to spring inwardly.

6. A mechanical pencil which comprises a plurality of manually operable relatively rotatable exterior parts, lead moving means including a helix within the exterior parts, a driving sleeve, the material of which is of uniform thickness sleeve, and a tension brake member within the throughout and including different diametered annular sleeve portions one of which has a snug t with the outside of the helix and the other a snug iii; with the inside of one of the exterior parts, said sleeve portions being connected by a tapered portion, a bearing secured to the upper end of one of the exterior parts to coact with the tapered portion to center the helix and to prevent longitudinal movement of the helix relatively to the exterior part in one direction only.

7. A mechanical pencil which comprises an exterior p art, a propeller helix therein, a driving rounding the dependent ears and some of which 10 form a bearing for the lead moving mechanism.

PAUL S. HAUTON.

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