US2177838A - Mechanical pencil - Google Patents

Description

Oct. 31, 1939. L. J. MOST MECHANICAL PENCIL Filed May 19, .1958

INVENTOR LJI float. BY

11 T I ORNEY Patented Oct. 31, 1939 UNITED STATES PATENT OFFICE MECHANICAL PENCIL Lucifer J. Most, Hudson County, N. J.

Application May 19, 1938, Serial No. 208,739

application, Figure 1 is an elevation, partially in section, on line I--I, Figure 3.

Figure 2 is an enlarged cross-section on line 2-2, Figure 1.

Figure 3 is a similar enlarged section on line 3--3, Figure 1, with the hopper partially broken out to show details of construction under it.

Figure 4 is an enlarged cross-section on line 4-4, Figure 1.

Figure 5 is a fragmentary elevation, partially in section, illustrating the lower part of the pencil magazine,

Figure 6 is an enlarged section on line 6-5, Figure 1.

Figure '7 is an enlarged section on line 'l--'I, Figure 6, and

Figure 8 is a section of a modified form of a pencil tip.

Referring to the drawing, I is an outer pencil shell or barrel which is open at the upper end II and tapered to a frusto-cone shape I2 at the lower end. Into the opening I3 of the frusto-cone I2 is fitted the reduced end I4 of a tip I5. The frusto-cone part of the shell I0 is formed by rolling it directly on to the reduced end I4 of the tip, so that the tip is secured to the shell to move therewith. The exposed part of the tip I forms a continuation of the taper of the lower end I2 of the'barrel I0.

Mounted within the outer shell I0 is a pencil magazinelfi, the upper end I! of which is made to accommodate a rubber I8 on the inside. At

4' the lower end, the magazine has a tapered portion I9 which leads into a tube 20, preferably of angular cross-section. As shown in the drawing, it is triangular, but any other shape may be used, and the corners do not have to be sharp.

The magazine I6 is free to revolve in the barrel II] but is prevented from longitudinal movements relatively thereto by the engagement of an annular bead 2| provided near the upper end of the magazine, which bead 2I engages a bead 22 formed in the barrel. The engagement between the two heads is obtained by slight pressure applied to the magazine when it is forced into the barrel.

The tip I5 has a countersunk bore 23 in which the tube of the magazine is free to revolve. The opening 24 of the tip below the countersunk bore is threaded and into that threaded portion enter prongs 25, which are formed at the free end of the tube 20 by cutting away the corners of said tube substantially through the length for which the opening 24 of the tip is threaded, so that the said prongs are free to turn therein when the tube is rotated, without interference with the thread in the tip.

The length of the tube 20 is such that when the prongs 25 are within the threaded portion 24, the shoulder formed by the cutting of the corners of the tube 20 is preferably sitting on the bottom of the counter bore 23 when the bead 2I engages the bead 22.

The leads 26 for this particular pencil are of a cross-section identical with the cross-section of the tube 20 which is to receive them, and are threaded with the same thread as that provided in the threaded opening 24. In consequence, when a lead 26 is permitted by the inclined conical portion I 9 of the magazine which forms the hopper thereof, to enter the tube 20, it is led by said tube toward the threaded part 24 of the tip I5, and is free to engage therewith when the magazine is rotated through the medium of a cap 21 which fits frictionally on to the exposed part of said magazine above the shell II). It is evident that the engagement of the tube 20 with the lead constrains the lead to rotate, but leaves it free to move longitudinally. The threads formed on the lead are only onthe corners thereof, so that the prongs 25 are easily accommodated in the clearance formed by the unthreaded portions of the lead and the threads in the opening 24 of the tip end.

As previously stated, the end of the tube 20 has prongs 25 which extend into the threaded part 24 of the tip. The purpose of these prongs is to permit the expelling of the extreme portion of the lead from the threaded part 24, so that a new lead following it could enter the threaded part. Thus it will be seen that in my pencil, the lead is propelled, expelled and repelled by the provision of the threads directly on the lead in conjunction with the threaded tip. There is no clutching mechanism as commonly used for gripping the lead, nor is there any special device for feeding the gripping mechanism.

Where the pencil is designed for lead of a larger size in cross-section, the tip could be made as shown in Figure 6, and the leads do not need to be threaded beforehand, the tip itself threading the lead as the magazine is turned, and for that purpose the threaded end 24' of the tip is made in the shape of a die so that the diameter of the threaded opening is slightly tapered and the full thread is formed at the tip end of the threaded opening 24.

Where the construction permits, the surface of the lead could be fluted or grooved longitudinally, in which case the tube will be made accordingly, and the purpose of the fluting or grooving is to permit a stronger type of prong 25, to insure the expelling of the last portion of the lead from the threaded opening 24 of the tip. The length of the prong does not exceed the length of about one-eighth of an inch, as that is the length of the threaded portion of the tip. It is evident that there is no strain on the prongs until the last portion of the lead enters thereinto. Previous to that, the tube itself does the driving of the lead through the threaded tip.

Although the description and the drawing show a magazine for lead independent of the barrel, the portion of the magazine above the hopper l5; and tube Fill could be dispensed with if the hopper and tube are secured directly to the barrel, in proximity of the taper of the barrel. In such case, the tip is revoluble and the operation of the pencil or its function will be identical with that described.

From the description, it will be seen that in my mechanical pencil there is a direct coupling action between the tip and the lead, obtained by the threaded engagement therebetween.

I claim 1. In a mechanical pencil, a tip, a magazine for leads revoluble relatively to the tip, said magazine having means for preventing the lead from turning while permitting it to move longitudinally thereof, and a lead adapted to engage said means, said tip and lead having inter-engaging means whereby the lead is fed longitudinally in the tip,

- said means for preventing the lead from turning entering the inter-engaging means.

2. In a mechanical pencil, a magazine for leads, and a tip revoluble relatively to the magazine, said magazine having means for preventing the lead from turning relatively thereto While permitting it to move longitudinally, said tip having means for a threaded engagement with the lead passing through. the means of the magazine, said means for preventing the lead from turning entering the means for a threaded engagement with the lead.

3. In a mechanical pencil, a barrel having a tip at the end thereof, a lead magazine in said barrel free to revolve but prevented from longitudinal movement relatively thereto, and means carried by said magazine for engaging a lead so that the same is constrained to revolve therewith but is free to move longitudinally thereof, said tip having means for engaging the lead when it is rotated by the magazine and whereby the lead is fed through the tip.

4. In a mechanical pencil, a barrel having a tip at one end thereof, a lead magazine in said barrel mounted to revolve therein but prevented from moving longitudinally thereof, a tubular extension from said magazine entering the tip, said extension being adapted to participate in all the movements of the magazine and to engage leads fed by the magazine so that the same are constrained to revolve with the magazine but are free to move longitudinally thereof, said tip having means for engaging the lead directly and causing it to move longitudinally when the leads are revolved relatively to the tip.

5. In a mechanical pencil, a barrel, a tip at one end of said barrel, a pencil magazine in said barrel mounted to revolve but prevented from longitudinal movement relatively thereto, a tube of angular cross-section extending from said magazine and entering into the tip, said tube being adapted to participate in all the movements of the magazine but is free to turn in said tip, said tip having a threaded portion and leads of similar cross-section as the cross-section of the tube carried by said magazine and adapted to be engaged by the threads of the tip.

6. In a mechanical pencil, a barrel having a tip at one end thereof, a lead magazine in said barrel free to revolve but prevented from longitudinal movement relatively thereto, a tubular extension from said magazine entering the tip and adapted to participate in the movement of the magazine, said tube being adapted to engage the leads fed by the magazine so that the same are constrained to revolve with the magazine but are free to move longitudinally thereof, said tip having a threaded portion for engaging the leads directly, and said tube having prongs entering the threaded portion of the tip.

7. In a mechanical pencil, a barrel, a tip at one end of said barrel, a pencil magazine in said barrel mounted to revolve but prevented from longitudinal movement relatively thereto, a tube of angular cross-section extending from said ma azine and entering into said tip, said tube being adapted to participate in the movement of the magazine, said tip having a threaded portion, said tube having prongs entering the threaded portion of the tip but free to revolve relatively thereto, and leads of similar cross-section as the cross-section of the tube carried by said magazine, the angular parts of said leads being adapted to be engaged by the threads of the tip.

8. In a mechanical pencil, a barrel having a tip at one end thereof, a lead magazine in said barrel mounted to revolve therein but prevented from moving longitudinally thereof, a tubular extension from said magazine for directing the lead to the tip, said tip being shaped to engage the leads fed by the magazine so that the same are constrained to revolve with the magazine but free to move longitudinally thereof, said tip having threads for engaging the lead passing through the tube, and said tube having means for forcing lead out of the threaded portion of the tip.

9. In a mechanical pencil, a barrel, a tip at one end of said barrel, said tip having an interiorly threaded portion at its end, a lead magazine in said barrel mounted to revolve but prevented from longitudinal movement relatively thereto, a tube of angular cross-section extending from said magazine and entering into said tip for directing a lead from the magazine to the tip, said tube being free to revolve in said tip but constrained to participate in all the movements of the magazine, a lead of similar cross-section as the tube having threads for engaging the threads in the tip, said tube having means located in the threaded part of the tip for engaging the lead whereby a portion of the lead outside of the tube but engaged in the thread of the tip may be expelled.

10. In a mechanical pencil, a tip, a magazine for leads revoluble relative to the tip, said magazine having a tube of angular cross-section entering the tip but constrained to move with the magazine, leads of similar cross-section as the tube adapted to enter the tube from the magazine, said tip and lead having inter-engaging threads and said tube having means at the inter-engaging threads of the tipand lead for causing said lead to revolve with the tube while leaving it free to move longitudinally.

11. In a mechanical pencil, a tip having an interiorly thread-ed part at the extremity thereof, a magazine for leads revoluble relatively to the tip, said magazine having a tube of angular cross section constrained to revolve therewith, a lead of similar cross-section as the tube adapted to have a threaded engagement with the tip in the angular portion thereof, said tube having means extending into the threaded part of the tip for engaging the lead thereat so as to cause it to revolve with the tube.

12. In a mechanical pencil, a tip, a lead, means for feeding the lead longitudinally, and means for preventing the lead from turning while permitting the lead to move longitudinally thereof, said last means being positioned in the means for feeding the lead.

13. In a mechanical pencil, a tip, a threaded lead, means for engaging the threaded lead to feed it longitudinally, and a second means engaging the lead so as to prevent it from turning While permitting the lead to move longitudinally of said second means, said second means extending into said first means. i

14. In a mechanical pencil, a lead of angular cross-section, threaded means for engaging the lead directly, lead guiding means within the

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