US2184527A

US2184527A - Mechanical pencil

Info

Publication number: US2184527A
Application number: US262590A
Authority: US
Inventors: Lucifer J Most
Original assignee: Individual
Current assignee: Individual
Priority date: 1939-03-18
Filing date: 1939-03-18
Publication date: 1939-12-26
Anticipated expiration: 1956-12-26

Description

Dec. 26, 1939. L. J. MOST MECHANICAL PENCIL Filed March 18, 1939 INVENTOR I, J flask NEY Patented Dec. 26,. 1939 UNITED STATES PATENT oFFic 7 Claims.

My invention relates to mechanical pencils, and is a modification of the pencil disclosed in my pending application, Serial No. 209,739, filed May The object of the invention is to supply a simple mechanism, formed of few moving parts, for propelling, repelling, expelling and automatically presenting a new lead to writing position.

Another object of the invention is to provide a mechanical pencil, in which the lead itself is a part of the feed mechani m.

A further object of the invention is to provide a pencil, which, when engaged by the fingers for writing purposes, will always present an edge of i a lead prism.

In the appended drawing, forming part of this application, Figure 1 is a fragmentary elevation, partially in section, of a pencil embodying my invention.

Figure 2 is an enlarged section on line 22, Figure 1.

Figure 3 is a similar enlarged section on line 3-3, Figure 1.

Figure 4 is a further enlarged section on line 4-4, Figure 3, and

Figure 5 is an enlarged cross-section on line 5-5, Figure 1.

Referring to the drawing, I0 is the pencil barrel or shell terminating with a frusto-cone portion H, having an annular groove [2. Fitted in the groove I2 is an exterior threaded split ring [3, provided at its upper end with a flange M. The peripheral edge of the flange is slightly larger than that of the adjacent periphery of the frusto-cone portion II. The split ring I3 is retained in the groove l2 by the engagement of its threads with the threads in the larger end of a hollowconically shaped tip 15. The edge of the larger end of the tip abuts against the flange when fully engaging the split ring, and will re volve therewith on the frusto-cone portion ll, although prevented from moving longitudinally thereof. To remove from or engage the tip with the ring, it is only necessary to grip the edge of the flange l4 exposed on the frusto-cone portion II, and to turn the tip or flange in the proper direction.

The cylindrical bore l6 of the barrel changes to a pyramidal bore ll of triangular cross-section as it approaches the frusto-cone portion H of the barrel, the truncated end of the pyramidal bore is merged with a hopper l8 of similar crosssection. The hopper leads to a bore 19 of triangular cross-section formed in the frusto-cone portion H, and it is the outlet for a lead 24 from the magazine formed by the barrel. The pyramidal bore ll, the hopper l8, and the bore Hi, all have their corresponding angles in common planes. v

The cross-sectional size of the bore E9 is corresponding in size to the cross section of the lead 2d that is to move therethrough longitudinally, it being prevented from turning therein by the angularity of the bore. The triangular bore in the frusto-cone portion H at its lower end is recessed, as indicated at 26 to accommodate firmly therein the. upper end of a tubular lead guide 2| of triangular cross-section of same size bore as that of bore 59, and of which it forms a continuation. The lower end of the tubular guide 20 is provided with prongs 2| formed by cutting away thereat the edges of the tubular guide 20, so that the prongs 2?. are really formed from the sides of the tubular guide 20 and constitutes with the sides; of said guide the means which guide the lead longitudinally, but prevents it from turning.

The prongs 22 enter into the threaded bore 23 formed in the lower end of the tip l5, and although positioned therein do not interfere with the turning of the tip and permit the threaded portion thereof to engage the edges of the lead 24 that is being engaged by the prongs within the threaded bore. The prongs 22 are really the lead guide which permits the extreme end of a lead section to be forced through the threaded bore 23, which forms the die that engages the lead to move it in any desired direction.

To always present an edge of the lead prism which is used in the pencil, the lower end of the barrel [0, in proximity of the frusto-cone portion H, is provided with tapering flat surfaces 25 increasing in width as they approach the frustocone portion II. The number of flat surfaces correspond to the number of flat surfaces the prismatic lead 24 has, in this particular case, the cross-section is triangular, and therefore there is only three flat surfaces, as best indicated in Figure 5, and the flat surfaces formed on the exterior of the shell are parallel to the fiat surfaces formed on the interior thereof, so that no matter which way the pencil is gripped between the fingers, there is always an edge of the prism of a lead in writin position.

I claim:

1. In a mechanical pencil, a barrel having a frusto-cone portion provided with a lead outlet, said frusto-cone portion having an external annular groove, a split ring positioned in said groove, a tip secured to said ring whereby said tip and ring are free to turn on said frusto-cone portion, said tip having a threaded bore aligning with the lead outlet, and a lead guide of angular cross-section from the lead outlet and entering the threaded bore, so that a lead engaged by the 5 threaded bore is prevented by said means within the bore from turning while it is free to move longitudinally.

2. In a mechanical pencil, a barrel having a frusto-cone portion provided with a lead outlet, said frusto-cone portion having an external annular groove, an exteriorally threaded split ring positioned in said groove, a tip threaded to said ring so that the tip and the ring are free to turn on said frusto-cone portion, said tip having a threaded bore aligning with the lead outlet, and a lead guide of angular cross-section from the lead outlet and entering the threaded bore, so that a lead engaged by the threaded bore is prevented by said means within the bore from turning while it is free to move longitudinally.

3. In a mechanical pencil, a barrel having a frusto-cone portion having a lead outlet, said frusto-cone portion having an external annular groove, an exteriorally threaded split ring positioned in said groove, saidring having at its upper end a flange, the peripheral edge of which is slightly larger than the periphery of the frustocone portion in the proximity of the flange, a tip threaded on said ring and abutting against the flange, whereby said tip is revolubly mounted with said ring on said frusto-cone portion of the barrel, said tip having a threaded bore in alignment with the threaded outlet, a lead guide of angular cross-section carried by the frusto-cone portion, prongs formed at the end of the guide remote from the frusto-cone portion, said prongs being positioned within the threaded bore of the tip.

4. In a mechanical pencil, a barrel having a lead outlet of angular cross-section, a tip having a threaded bore revolubly mounted on the barrel to engage a lead of same angular cross-section as the lead outlet, and means within the threaded bore of the tip for engaging the lead therein so that the lead is free therein to be engaged by the threaded bore, but prevented by said means from turning while it is free to move longitudinally,

said barrel having as many fiat surfaces at its outer periphery in proximity of the tip as there are faces in the lead outlet.

5. In a mechanical pencil, a barrel having a lead outlet, a tip having a threaded bore revolubly mounted on the barrel, and a lead guide of angular cross-section at the outlet, said guide having means positioned within the threaded bore so that it leaves the threads of the bore free to engage the edges of a lead passing through the guide in the bore, but prevents the lead from turning in the bore, said barrel having as many fiat surfaces on its outer periphery, widening towards the tip as there are faces in the lead guide, the angles formed by the surfaces of the barrel being substantially coplanar with the angles of the lead guide.

6. In a mechanical pencil, a barrel having a lead outlet of angular cross-section, a tip having a threaded bore revolubly mounted on the barrel to engage a lead of same angular cross-section as the lead outlet, and means within the threaded bore of the tip for engaging the lead therein so that the lead is free therein to be engaged by the threaded bore, but prevented by said means from turning while it is free to move 1ongitudinally, said barrel having as many fiat surfaces at its outer periphery as there are faces in the lead outlet, said surfaces being so disposed that when gripped for writing purposes the tip will present the lead with one of its edges for writing purposes.

7. In a mechanical pencil, a barrel having a lead outlet, a tip having a threaded bore revolubly mounted on the barrel and a lead guide at the lead outlet adapted to engage a lead so that the lead is free to move longitudinally in the guide, but prevented from turning therein, said barrel having as many fiat surfaces on its outer periphery in the proximity of the tip as there are faces in the lead guide, the said flat surfaces on the periphery of the barrel being so disposed that when gripped for writing purposes the lead fed by the tip will present one of its edges for writing purposes.

LUCIFER. J. MOST.