US2434234A

US2434234A - Three-color mechanical pencil

Info

Publication number: US2434234A
Application number: US650403A
Authority: US
Inventors: Russell N Thatcher
Original assignee: Individual
Current assignee: Individual
Priority date: 1946-02-27
Filing date: 1946-02-27
Publication date: 1948-01-06
Anticipated expiration: 1965-01-06

Description

6, 1948. R; N. THATCHER THREE-COLOR MECHANICAL PENCIL Filed Feb. 2.71946 2 Sheets-Sheet l INVENTOR.

Jan 6 l943- R. N. THATCHER 2,434,234

THREE-COLOR MECHANICAL PENCIL Filed Feb. 27, 1946 2 Sheets-Sheet 2 Patented Jan. 6, 1948 UNITED STATES PATENT OFFICE Claims.

This invention relates to a mechanical pencil, and one of its objects is to provide a pencil with a series of lead holding shanks and means for successively withdrawing the shanks and the leads from service position, and successively moving the shanks to service position, so that the colored lead desired may be placed in service position, and its location determined by means of an observation window and enamel on the lead shanks.

Another object of the invention is to provide a pencil barrel with a bearing through which the plurality of lead holding shanks extend, which is mounted to turn with the barrel, and a hollow screw which is carried by a tube mounted to turn in the barrel, and which is engaged by cams formed on the upper ends of the lead holding Shanks, the cams being shifted successively by rotative action to sliding connection with a slotted tube disposed within the hollow screw, so that each lead holding shank may be propelled outwardly or inwardly through the tapered end of the pencil barrel.

With the above and other objects in View, the invention relates to certain new and useful constructions, combinations and arrangements of parts, clearly described in the following specification, and fully illustrated in the accompanying drawings, in which:

Fig. 1 is an enlarged longitudinal sectional view through the three color pencil.

Fig. 2 is a fragmentary side elevation showing the series of lead holding Shanks and the bearing through which these Shanks slide, the latter being shown in section.

Fig. 3 is a top end view thereof.

Fig. 4 is a perspective view of the hollow screw, showing the upper connecting tube in part section.

Fig. 5 is a side elevation of the slotted tubular guide.

Fig. 6 is a top end view thereof.

Fig. 7 is a fragmentary sectional view, showing the position of one of the cam lugs in the selector notch and with reference to the screw thread of the hollow screw.

Fig. 8 is a transverse sectional view through the assembled pencil, taken above the cam lugs.

Fig. 9 is a similar view, taken above the bearing.

Referring to the accompanying drawings, 5 designates a tubular pencil barrel, which may be of cylindrical or hexagonal construction, and

which is formed with a tapered forward end portion 6, which is provided with external screw threads engaged by the internally screw threaded lead guide l.

In the barrel 5 a tubular bearing 8 is tightly fitted and soldered to the inner surface of the barrel 5, at a point approximately midway of the ends of the barrel. In this bearing a plug 9 is mounted to turn, and this plug is formed with a vertical slot I for each of the lead holding Shanks il, I2 and I3.

Each lead holding shank is approximately rectangular in cross section, and is formed on its forward end with a lead holding socket clutch I4, in which the lead stick I5 is tightly gripped, and which projects endwise of the socket clutch. The upper end of each lead holding shank is formed with an outwardly directed cam Il. Each cam is formed with a rounded edge portion Ila and a straight edge portion I'Ib.

The plug 9 is formed with an upstanding central portion 9a and the flange Ia of the tubular guide I8 rests on this plug and is held central by the upstanding boss or central portion 9a.

The tubular guide is interlocked to the pencil barrel through its flange I8a, which is formed hexagonal for this purpose. This guide is formed with a longitudinal slot I9, which extends from the flange Ia, but does not pass through this ange, to the shoulder 20, which is located below the upper end of the guide. The slot I9 is widened above the shoulder 2li, and one edge lila of this slot is formed with a helical curve ISD, and the other edge I9c is formed with a knife edge IBd, which extends parallel to the length of the tubular guide I8, the knife edge I9d facing outwardly on the tubular guide, as shown in Fig. 6.

On the tubular guide I8 the hollow screw 2l is disposed, and the upper end of this hollow screw is fitted in the tube 22, which is disposed in the upper end of the barrel 5. The tube 22 is interlocked to the hollow screw by means of the indents 2 la and 22a, which fit one within the other.

The tube 22 is provided with an internal bead or shoulder 22h, and projects above the upper end of the pencil barrel 5, to receive the rubber eraser 23. A cap 24 is fitted on the tube 22, and the lower edge of this cap is formed with a rising bevel 24a, and the upper edge of the pencil barrel 5 is formed with a matching bevel 5a.

The upper end of each of the pencil lead holding shanks is sprung outwardly, as shown in Fig. 2. Each of the cam lugs is disposed at an incline with reference to the aXis of the pencil. The cam lugs are moved successively into the narrower slot I9 by rotating the barrel while the friction cap 24 is held, or by rotating the friction cap while the barrel is held. By producing rotative movement so that the guide I8 moves in a right hand direction relative to the hollow screw, the cam engaged with the slot I9 will be shifted downward.

When any cam is propelled upwardly out of the slot I9 it will ride along the shoulder 2U and be moved into engagement with the knife edge I9d, and will be forced by this knife edge inwardly of the wall of the tubular guide I8. When the cam is further moved so that it will pass the helical edge I 9b it will be forced downward back into the slot I9.

The rotation of the screw 2| with respect to the guide toward the right with respect to Figure 7 will raise the particular cam I'l in guide slot I9 up out of the slot to a point where it is above shoulder 20. At this point, recess 2 Ib of the screw 2l will carry the cam to the shoulder. The recess 2| b acts as a selection recess since it carries the cams around at the upper end of their stroke to positions where they successively engage the guide slot.

Selection of the wanted color lead is obtained through the selection recess or notch 2lb of the hollow screw 2|, which is located below the insert tube 22, and slightly above the plane of shoul der 20. When the cam lug is moved from the helically curved I9b it will snap through the slot I9 of the guide tube I8, and will be forced by the screw pressure of the hollow screw downwardly through the slot I 9, so that the lead carried by the shank of the cam lug, will be moved through the lead guide at the forward end of the pencil barrel. This movement is aided by the free sliding action of the lead holding shanks through the guide plug 9. The inclined disposition of the cam lugs provides the desired bearing engagement with the helical threads of the screw, so that wear is taken up by the full width of the cam lug.

The pencil tube or barrel 5 is formed with a window 25 in the wall thereof, which is located below the bearing B and each of the pencil lead holding shanks is brightly enameled with a color to indicate the color of lead for which it is used.

The window 25 is shown at the side in Figure 1. Preferably it should be in line with the guide slot I9. But when the window is at the side, the lead holding shanks may be appropriately colored so that the color of the shank opposite the window will indicate the color of the lead aligned with the guide.

The drawings illustrate a pencil equipped with three pencil lead holding shanks, which may be supplied with red, black and blue colored pencil leads, or any other combination desired. For most purposes these three colored leads will serve.

The user of therimproved pencil can quickly shift any lead from service position to an interior position, and shift the required colored lead to service position, operating the relatively rotative parts to produce the required outward or inward propulsion of the lead disposed in service position.

It is understood that various changes in the details of construction, their combination and arrangement, may be made, Within the scope of the claims which define the invention.

Having described the invention, I claim as patentable:

1. A pencil having a barrel provided with a pencil guide on its forward end, a bearing in the barrel, a plurality of pencil lead holding shanks each being rectangular in cross section, a plug mounted to turn in the bearing and formed with a slot for the sliding movement of each of said shanks, a lead holding socket on the forward end of each shank, a tubular guide disposed on the bearing and interlocked to the barrel against relative rotative movement, said guide having a longitudinal slot widened at the upper end thereof, a hollow screw enclosing the tubular guide and provided with a selector notch formed in the screw thread thereof, and a tube having a friction t in the barrel and coupled to the screw.

2. A pencil having a barrel provided with a pencil lead guide on its forward end, a bearing cup secured to the barrel within the same, a plug mounted to turn in the bearing cup and provided with a series of slots, a pencil holding shank slidable in each slot and held against relative rotative movement therein, a cam lug on the upper end of each shank, a tubular guide having a base flange interlocked to the pencil barrel against relative rotation and provided with a longitudinal slot extending from said base flange through the upper end thereof, the upper end of said slot being widened to provide a shoulder and a knife edge on one side thereof and a helically curved edge on the opposite side thereof, the upper ends of the shanks being sprung outwardly to cause said cam lugs to successively engage said shoulder, knife edge and` helical edge and enter the longitudinal slot of the tubular guide, and a hollow screw having a friction bearing in the upper end of the barrel and enclosing the tubular guide and provided with a screw thread having a selector notch located adjacent to the wide end of said slot.

3. The construction set forth in claim 2, each of the shanks being colored to designate the color of the pencil lead it holds and the wall of the barrel having a window for observing the color of said shanks.

4. A writing instrument having a barrel and a plurality of marking members; said barrel being provided on its forward end with a marking member guide, a bearing cup secured to the barrel within the same, a plug mounted to turn in the bearing cup and provided with a series of slots, a marking member retainer slidable in each slot and held against j relative rotative movement therein, a cam lug on the upper end of each retainer, a tubular guide having a base flange interlocked vto the barrel against relative rotation and provided with a longitudinal slot extending from said base flange through the upper end thereof, the upper end of said slot being widened to provide a shoulder and a knife edge on one side thereof and a helically curved edge on the opposite side thereof, the upper ends of the retainers being sprung outwardly to cause said cam lugs to successively engage said shoulder, knife edge and helical edge and enter the longitudinal slot of the tubular guide, and a hollow screw having a friction bearing in the upper end of the barrel and enclosing the tubular guide and provided with a screw thread having a selector notch located adjacent to the wide end of said slot.

5. A writing instrument having a barrel and a plurality of marking members, said barrel provided with a marking member guide on its forscrew thread thereof, and a tube having a. friction fit in the barrel and coupled to the screw.

RUSSELL N. THATCHER.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS 0 Number Name Date 1,732,591 Caballero Oct. 22, 1929 2,071,510 Durrler Feb. 23, 1937