US2528839A

US2528839A - Mechanical pencil

Info

Publication number: US2528839A
Application number: US689033A
Authority: US
Inventors: John H Mason
Original assignee: Individual
Current assignee: Individual
Priority date: 1946-08-07
Filing date: 1946-08-07
Publication date: 1950-11-07
Anticipated expiration: 1967-11-07

Description

Nov. 7, 1950 J. H. MASON MECHANICAL PENCIL Fil'ed Aug. '7, 1946 FIG. I. Ea

FIG.3.

//Vl/E/VTOR gO/ZIZ [2 Mason,

ATiORN/EYS Patented Nov. I 7, 1950 UNITED STATES PATENT OFFICE 3 Claims.

This invention relates to a mechanical pencil, and mor particularly to a pencil having manually operable mechanism for positively advancing a lead to and holding it in right position.

In accordance with one embodiment of my invention, my pencil may take the form of a casing in which is enclosed a tube adapted slidably to house the lead. Also, in this tube is an impelling member capable of incremental movement by a finger piece for forcing the lead out of the pencil as desired by the user. I also provide means for resisting movement of the lead back into the pencil housing from writing pressure, or the 1ike.

In accordance with another feature of my invention, the rear end of the pencil housing or barrel is removable and the finger piece, which is operable to feed lead out of the pencil, is movable or rather operable transversely of the axis of the barrel.

In the drawing, wherein I have shown one form of my pencil,

Figure 1 is a sectional elevation of the pencil;

Figure 2 is a perspective view of the pencil, a portion thereof being broken away to show the lead advancing and holding mechanism; and,

Figure 3 is a side elevation of the pencil.

Similar reference characters refer to similar parts throughout the views of the drawing.

Referring first to Figure 1, my pencil comprises a body or barrel, generally indicated at Ill, which may be formed of any suitable material. Thus the pencil barrel may be molded of a suitable plastic, or may be fabricated from metal tubing, with a suitable filler inserted therein to form the relatively solid and heavy portion ll of the writing end of the pencil. The mass of portion I l of the pencil barrel is of advantage in that it weights the writing end of the pencil, thus facilitating its use. The writing end of barrel I is provided with an elongated concentric bore I2 in which is fixed in any suitable manner an elongated tube I3, the left-hand end of which may be flush with the end [0a of barrel ID. If desired, however, bore I 2 of barrel It] may be just large enough to accommodate a lead, and may be shouldered (not shown) at its right-hand end to provide a seat for the left-hand end of tube [3. Preferably tube end 13a is slotted or pinched as at I3b, or otherwise conformed to a diameter just slightly less than the diameter of the pencil lead, so as to preclude the leads falling out of the pencil.

The right-hand end I30 of tube I3 is disposed in and may be fixed to a collar l4 secured in any suitable manner to the right-hand end lllb of barrel it within a chamber lilo formed in the barrel. Thus collar i i may be press fitted into the barrel, or may be pinned, if desired, in proper position therein, properly to position and hold tube iii. If desired, collar i i may have one or more openings Ma extending therethrough, through which leads may be inserted, thus to be stored within barrel chamber Mic. The open end of barrel end lllb may be filled by a cap which conveniently holds an eraser [5.

Tube it, of course, comprises a lead tube for the reception of lead it, and also acts as a holder and guide for a feed rack ii, the left-hand end Ila of which is adapted to abut the right-hand end lfia. of lead I6, and upon movement force the lead to the left by means of the manually operable mechanism, generally indicated at [8.

As is more clearly shown in Figure 2, the manually operable mechanism iS may :comprise a resilient stop finger I9 and a feed finger Zll, secured at their right-hand ends in any suitable manner to tube l3. The left-hand end of stop finger i9 is downwardly bent to provide a foot 2i adapted to engage rack l'l between adjacent teeth thereof. In other words, stop finger l9, together with its foot 2 l comprises a pawl or detent which is so sprung as to be under a counterclockwise bias, thus to permit movement of rack I! to the left, but to preclude movement thereof to the right unless raised out of ratcheting engagement with the rack. The left-hand end of feed finger 20 overlies foot 2! of finger l9, and is curved downwardly to provide a foot 22, the end of which is adapted to engage the teeth of rack ll. It should be noted that the feet 2| and 22 of fingers l9 and 25 enter tube is by way of an opening i3a cut therein.

To the top of finger 20 is secured a finger piece 23, as by a screw 2 and this fingerpiece extends through an opening 25 cut in barrel l9. Finger 2!! overlies finger l9 and is in effect bowed so that in rest position it is somewhat spaced from finger [9. It accordingly follows that when fingerpiece 23 is pressed inwardly of the pencil barrel M3, finger 2i! flattens, and in so doing elongates in such manner that its foot 22 is forced to the left, thus to drive rack l7 and accordingly lead [6 to the left a distance equal to at least one tooth of rack l7. Upon release of fingerpiece 23, the resilience of finger 20 restores the bow to spring 28, and in so doing causes movement of its feet 22 to the right, thus to engage it with another tooth of the rack, finger 20 thus being restored to its lead feeding position. During the feeding action over one or more of the rack teeth, thus securely to hold the rack in its new position, thereby precluding movement of the rack to the right during return movement of finger 2! and from writing pressure exerted on the rack through lead 56. Thus it may be seen that lead l6 may be advanced in increments until the lead is exhausted.

Fingerpiece 23 is preferably so dimensioned, i. e. its height is such that when finger 20 (Figure 1) is completely flattened, i. e. is flattened to a point beyond that necessary to move rack i! one notch, the upper surface of the fingerpiece underlies the inner surface of barrel portion lflb. By so dimensioning the fingerpiece tube l3, rack I! and the fingers l9 and 28 attached to the tube may be installed in or removed from the pencil barrel as a unit, thus facilitating initial assembly of the pencil, or subsequent repair thereof.

Preferably rack I7 is of such length that its left-hand end Ila will protrude slightly from tube end [3a before it is disengaged by the feed on the ends of fingers l9 and El], thus to warn the user not only that the lead is exhausted, but also that the rack should be restored to the position shown in Figure 1, thus to preclude the rack from becoming completely disengaged by the feeding mechanism 68.

It may accordingly be seen that through the manipulation of feeding mechanism l8, lead I6 is positively and incrementally fed to the left as additional lead is required, and is positively held by finger l9 and its foot 2! against writing pressure, which otherwise might well cause the lead to be forced back into the pencil barrel.

It is, of course, necessary to provide means for refilling or reloading the pencil with new lead. To this end, I have attached a strap 26 (Figure 2) to the lower finger l5, the upper end of this strap being provided with a lip 2'! which overlies, but is not secured to the top of finger 2t. Thus it follows that both of fingers l9 and 20 may be lifted out of engagement with rack l1 merely by grasping fingerpiec 23 and pulling it outwardly of the pencil barrel. Upon such manipulation, finger 2i] pulls outwardly on strap 26 and accordingly draws finger l9 outwardly therewith. With the two fingers thus out of ratcheting engagement with rack ll, it is but a simple matter to insert a new lead into tube l2 and force it into the. pencil barrel, thus moving rack l! to the position shown in Figure 1.

Under certain circumstances, finger I9 may be dispensed with, finger 2'0 and its foot 22 acting as both a feeding and stopping element. Under such circumstances, however, the right-hand end of rack I! is notched as at llb, and the end of the rack spread so as frictionally to engage the inside of tube l3. The value of th frictional engagement of the spread end of the rack with the tub should be sufiicient to prevent movement of the rack to the right during the return action of finger 2G and the consequent dragging effect of its foot 22 on the rack, which might well force the rack to the right and thus prevent the feeding of lead.

As shown in Figure 3, the pencil barrel is provided with a conventional clip 30, the free end SI of which lies between the writing and eraser ends of the pencil. Clip 30 is preferably so attached to barrel I'll as to be angularly displaced from fingerpiece 23, so that when the pencil is clipped in the users pocket, fingerpiece, 2.3 is not engaged as the pencil is placed in the pocket or removed therefrom. Therefore, by an gularly displacing the clip and fingerpiece, the

,4 fingerpiece is conveniently located so as to be operated by the user without materially changing his writing grip on the pencil.

It may now be seen that I have provided a pencil which attains the several objects set forth hereinabove in a thoroughly practical and efficient manner.

As many possible embodiments may be made of the above invention, and. as many changes might be made. in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawing is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. In a mechanical pencil, in combination, a barrel, a lead tube in said barrel, a notched feeding element in said tube adapted to be moved axially thereof for feeding lead therethrough, a bowed resilient member having one end connected to said tube and the other end extending through a hole in said tube to engage said notched element whereby, when said bowed member is flattened and accordingly elongated, said notched element is advanced in lead-feeding direction, means extending transversely of and through said barrel to an accessible position and connected to said bowed member for operating the same and accordingly moving said notched element, and means for positively precluding movement of said notched element in non-lead feeding direction, said transversely extending means comprising a finger piece so dimensioned that its outer end lies within said barrel when said resilient member is completely flattened, whereby said tube, said element, said member, and said finger piece may be installed in or removed from said barrel as a unitary assembly.

2. In a mechanical pencil, in combination, a

barrel, a lead tube in said barrel, axially'movable means in said tube for feeding lead therethrough, a reciprocable finger piece projecting transversely through said barrel and connected with said feeding means for moving said feeding means in a direction to feed a lead through said lead tube out of said barrel, and means on said axially REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,866,072 Woelm July 5, 1932 FOREIGN PATENTS,

Number Country Date 10,297 Great Britain 1 1844 281,418 Germany Jan. 5, 1915