US1821183A - Mechanical pencil - Google Patents

Description

Sept. 1, 1931. c. R. KEERAN MECHANICAL PENCIL Filed June 10, 1927 .whiff mm,

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as zarpeys Patented Sept.. l, 1931 UNITED` STATES PATENT OFFICE CHARLES KEERAN, OF 4,EVAJTSIOII', ILLINOIS, A'SSIGNOR TO DUR-O-LITE PENCIL COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS l MECHANICAL PENCIL Application filed June 10,1192?. -Serial No. 197,793.v

The object of this invention is to provide an improved construction for a mechanical pencil, in which the lead propelling mechanism shall be removable from the barrel substantially as a unit, andshall have associated with it a magazine for the spare leads.

Another object. of thev invention is to' pr0- vide a construction which shall be economical to manufacture and durable in use. It con- .;-3 sists of certain features and elements in comg3 pencil embodying this invention.

Figure 2 is a similar axial section, sho\ving a. slightly modified construction for the guide tube and tip of the pencil.

Figure 3 is an enlarged detail section taken axially of the pencil. and showing certain parts of the propelling mechanism.

Figure 4 is a transverse section, taken as indicated at line 4--4 on Figure 1. y

Figure 5 is a transverse detail section as indicated at line 5-5 on Figure 1.' i

Figure 6 is a transverse detail section as indicated at line 6-6 on Figure 1.

Figure 7 is a transverse perspective view of a fragment of the square tubing employed to prevent rotation of the lead propelling plunger'.

Figure 8 is a side elevation of the remova-` ble tip including a much exaggerated indication of the method of ldeforming this part toinsure adequate friction in the barrel.

Figure 9 is a transverse detail section taken as indicated at line 9-9 on Figure l.

Figure 10 is a detail section indicating a special construction of the barrel as it would appear at the plane indicated by line 4-4 on Figure 1; the elliptical form of the bore, however, being exaggerated.

In the construction illustrated the main body or barrel of the pencil is shown at, 10, and may be formed of any suitable material, such as wood, metal, lbakelite or other molded composition, and atthe lower end it is bored to receive a bushing tube, 11, in vwhich the hollow cylindrical sleeve portion, 12, of the .pencil tip isrotatively engaged.

, In operation the part, 12, is integral with the tip, but for convenience of manufacture it is formed at the lower end with an enlarged portion, 18, and a. tapering portion, 14, which are forced tightly into the tapering shell, 15, of the tip. -Within the shell, 15. a guide tube, 16, for the lead, 17, is secured, and eX- tends upwardly within thesleeve, 12, into abutment with vits reduced neck, 18. The space between the sleeve, 12, and the guide tube, 16,thus becomes an annular chamber `for the storage of spare leads, one of which is seen in Figure 1, at 19. The upper end of this chamber is formed with apertures, 20, through which theleads, 19, may be in* troduced or discharged, as needed.

The neck, 18, of the sleeve, 12, is interiorly threaded for feeding engagement with the threaded plunger, 21, whose lower end contacts with the upper end of the lead 17, for propelling it through the guide tube, 16, as the lead wears away in use.

The plunger is held against rotation by engagement of its square upper end, 22, in the v square bore, 23, of an axially disposed tube, 24. extending in the barrel, 10, from a point adjacent the neck, 18, to the upper end of the pencil. It will be recognized that this square bore, 23, might be formed directly in the material of the barrel, 10, but by providing the tube, 24, axially disposed within a considerably larger bore, 25, of the barrel,

10, I secure an additional space of approximately annular form at, 25, which may serve as asecond magazine for spare leads, such as that indicated at, 26, in Figure 1.

A plug 27, forced into the lower bore of the barrel, 10, up to a shoulder, 28, at which the upper bore, 25, terminates, serves as a bottom for the upper magazine and also as a plug, 27, I have shown the corners of the tube, threaded at, 28, as seen in Figure 7, so

ythat it canv be screwed into a tight fitting threaded bore in the plug, 27.

The squared end, 22, of the plunger, 21, is smoothly slidable in the square bore, 23, and travels substantially from one end to, the

:15, and shouldered at 30, to form a butt joint with said shell. Spaced from the shoulder, 30, Within the shell, 15, a plug Washer, 3l, is inserted to center the tube, 16, and to form a bottom Wall for the annular lead magazine. Preferably the tube, 16, is formed with threads at 32, adjacent the shoulder, 30, and the small end of the shell, 15, is interiorly threaded, so that in assembling the parts the tube, 16, may be inserted into the shell, 15, after the sleeve portion, 12, has been secured in place. By screwing the threaded portion, 32, into the end of the shell, 15, until the shoulder, 30, firmly abuts the end ofthe shell, the upper end of thetube, 16, Will be brought substantially into contact with the inner end of the neck, 18.

As an alternative construction the tapering tip shell may be made as seen at 15a in Figure 2, in which the guide tube, 16, is not made With an enlarged terminal, but stops short Within the shell, 15a, While the latter 'extends to the extreme tip of the pencil. A plug Washer, 31, is used in the same manner as in Figure 1, and the upper end of the guide tube abuts the inner end of the reduced neck, 18. as herein shown.

The advantage of the terminal, 29, shown in Figure 1, is that this heavier construction at the tip provides a bore for the lead, Which Will retain its size and shape somewhat better than the thin-Walled terminal of 'Figure 2; it is common practice to slit the extreme tip, as indicated at 33, in Figure 8, in order to provide a `yielding grip for the lead, and this makes it possible for the tip to be sprung open slightly if the user applies too much pressure laterally of the lead, when the tip is of thin stock.

To insure sufficient friction between the sleeve, 12, and the bushing, 11 (or the bore of the barrel, 10, if the bushing is omitted), the sleeve, 12, may be slightly distorted by bending it as indicated in Figure 8, although in the drawings this bending is greatly exaggerated for the sake of clearness. lVith such initial bend the sleeve will not remain bent after it is inserted in the bore of the barrel, 10, but While itl is sprung to fit the straight bar of the barrel there will be a resulting stress in the metal, which will produce the desired friction, so as to hold the rotatable tip of the pencil at any adjusted position.

Figure 10 suggests another method of securing this desired friction, which consists in forming the bore of the barrel, 10, and the bushing 11, if the latter is'employed, so that 'in cross section it is very slightly elliptical instead of circular. This is a vparticularly VV i simple matter, if no bushing is employed. and the bore is simply moulded in the barrel, 10. This will result in a slight distortion of the sleeve, 12, within the limits of elasticity, when the sleeve is inserted in the barrel.

Figures 1 and 9 illustrate a very simple and effective method of attaching the spring clip, 34, to the barrel, 10. *.The clip is offset as usual at 35 and terminates in a straight tang, 36, which fits snugly in a longitudinal groove, 37 cut in the barrel, at the reduced portion, 38, extending from a shoulder, 39, to the upper end of the barrel. The groove includes a radial portion at 40 to accommodate the offset part, 35, of the clip, and to hold the clip in this position a tight retaining ring, 4l, is forced on to the reduced barrel at 38 over the tang, 36, and against the part, 35. A removablesleeve, 43, holding an eraser, 44, may be fitted over the ring, 38, toprovide a finish for the upper end of the pencil, the eraser being secured. in the sleeve in any preu ferred manner, permitting it to be replaced when worn. Obviously, if desired, a merely ornamental cap (not shown) may be substituted for the sleeve, 43, or may be applied over it to keep the eraser clean when notin use. p

From the foregoing description it will be seen that this construction Will be comparatively simple to manufacture and assemble, and will be sturdy and reliable in use; and further that the provision of two magaznes for spare leads is an unusual advantage. If the user will make it a habit to refill the guide tube, 1,6,.eXclusively from one of the magazines,until its contents isexhausted, he will be thus reminded to secure a new supply and will have the contents of the other magazine available until he can conveniently refill the first magazine.

It may also be mentioned that a pencil, I

made in the proportions indicated in the drawing and approximating 51/2 inches in extreme length, is adapted to utilize leads fully 2 inches long instead of the conventional 11/2 inch leads generally in use.

It will be noted that the lead guide tube, 16, particularly in the form shown in Figure 1 is readily removable from the tip by unscrewing it at the threads at 32. This is of particular advantage in connection wit-h any repair Work Which-may be necessary on the tip itself or in the event that the spare leads in the magazine, sleeve, 12, should become broken and crumbled so that in some Way the guide tube might be sprung out of line. By merely unscrewing the tube, 16, the interior ofthe shell, 15, and sleeve, 12, becomes readily accessible and can be cleared out quickly a tapered portion and reduced cylindrical portion extending rotatively into said barrel and an axially disposed guide tube in the tip 'extending through the reduced portion and forming an annular magazine chamber for leads in said tip, said guide tube having a terminal portion outside the smaller end of the tapered tip and larger than the remainder of the tube so as to form a shoulder against which the end of said tip abuts, said tube ad'- jacent the shoulder being threaded and screwed into the smaller end of the tapered tip.

2. In a mechanical pencil, a tip comprising a tapered shell and a guide tube extending substantially throughout the length of said shell formed with a terminal portion exposed beyond the smaller end of the shell, said portion being larger than the remainder of the tube and providing a shoulder abutting said end of the shell and the shell having an opening at its upper end adjacent the end of the guide tube for admitting a lead thereto. n

3. In the combination defined in claim 2, the shell being reduced at its upper end to approximately the bore of the guide tube end such reduced portion being internally threaded to engage a threaded plunger which extends into the tube.

4. In a mechanical pencil, a barrel and a tip, said tip comprising a tapered shell portion and a sleeve portion fitting rotatively into the end of the barrel, said sleeve portion haring an enlargementV at its lower end forming a shoulder abutting the end of the barrel and including a fiange tightly telescoped with the tapered shell. together with means carried by the tip and barrel for propelling a lead through said tip upon relative rotation of the tip and barrel.

5. In the combination defined in claim et, a guide tube for leads extending substantially throughout the sheil and sleeve of the tip with an enlarged terminal forming a shoulder abutting the smaller end of the shell said lead propelling means including a plunger for adt vancing the lead in said tube.

G. In a mechanical pencil, a barrel, a tapered tip having a reduced sleeve portion secured thereto and telescoped in the barrel and rotatable therein and a guide tube for the lead removably secured in said tip and extending substantially throughout the length of the sleeve.

CHARLES R. KEERAN.

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