US2319823A - Mechanical pencil - Google Patents

Description

May 25, 1943. F. P. MOORE MECHANICAL PENCIL riled mayA 25 1942 IN V EN TOR. Hed EMM/"e,

Patented May 25, 1943.

MECHANICAL PENCIL Fred P. Moore, Chicago, Ill., assignor to Eversharp, Inc., Chicago, Ill., a corporation of Dela- Ware Application May 25, 1942, Serial No. 444,332

(Cl. 1Z0-17) 19 Claims.

jects the simplication and reduction in cost of manufacture of such pencils, and for a particular object the provision of a construction which eliminates the inaccuracies and uncertainties resulting from necessary tolerance variations of various parts of the mechanism, and hence provides a pencil having the desired certainty and accuracy in the lead feeding operations.

Other and further objects of the invention will be pointed out or indicated hereinafter or will be apparent to one skilled in the art upon an understanding of it or use of it in practice.

For the purpose of explaining the nature of the invention, I show in the accompanying drawing, and hereinafter describe, one form in which it may be embodied. It is to be understood, how,

ever, that this is presented merely by way of illustration, and hence is not to be construed in any fashion for the purpose of limiting the appended claims short of the true and most comprehensive scope of the invention in the art.

In said drawing,

Fig. 1 is a side view, partly in section, of a pencil mechanism embodying the invention;

Fig. 2 is a showing in perspective of various parts of said mechanism disassembled;

Fig. 3 is an elevational view of one of the stave members forming a part of said mechanism; Y

Fig. 4 is a lateral view of such stave member, showing only its upper and lower portions, on a scale considerably larger than that of Fig. 2;

Fig. 5 is a longitudinal sectional view illustrating a pencil with the mechanism of Fig. 1 embodied therein, same being on a considerably larger scale than Fig. 1 and being shortened by the breaking out of a portion of the device; l

Fig. 6 is a cross section on line S--B of Fig. 1 but on a larger scale; and

Fig. '1 is a cross section on line 1-1 of Fig. 1 but on a larger scale.

In the manufacture of mechanicalp'encils of the type wherein lead sticks are fed successively from a magazine to the writing point in a stepby-step manner, it has been the practice to form the magazine of tubular stock and to form the lead gripping members separately from the magproduction various tolerances have to be allowed in the size of the various individually formed parts, it has been an undesirably frequent occurrence that, due to the tolerance variations in the different parts, the assembled device is not prop-v erly or accurately operative. Such instances may occur, for example, when the lengths of various individual parts assembled in a given pencil are at the minimum tolerance limit or when the lengths of the various parts assembled in a given pencil are at the maximum tolerance limit. The present invention eliminates such diiiiculties and thereby greatly reduces the number of rejects and, moreover, greatly simplifies the manufacture and produces a more accurate, desirable and economical device.

The nature of the invention will be ascertained most quickly from a description of the illustrative embodiments shown in the drawing, which is as follows.

To form the magazine and the lead,gripping members, I provide a plurality of complementary stave-like members of the form illustrated in Figs. 3 and 4. These may be formed of suitable sheet metal by die press operations. Each of these staves is shaped with a. transversely arched magazine portion I0 which, as in the instance where three stave members are employed to form the magazine, as hereinillustrated, forms an arc or segment having an extent of degrees. At the upper end of the stave member, marginal parts of the magazine portion are flanged inwardly as shown at I I in Fig. 6. At its lower end the magazine portion I0 is formed with a downwardly tapering portion I2 from which project radial flange portions I4 which, as they continue downwardly, are reduced in Width to form collarseats I5 and spring guide flanges I 6. Continuing downwardly from the anges I6, the width of the stave is still further reduced and it is arched transversely to form a lead guide portion I1 from which extend narrow radial flanges I8. The narrowed portions of the stave which are below the flanges I6 are also gripper arm portions, and they are given a set in an outwardly bowed form, as illustrated in the lower portion of Fig. 4, from which position they may be swung inwardly against their inherent resiliency. At a distance below the spring guide flanges I6 thenarrow lateral flanges I8 are widened for a short distance to provide radially extending stop lugs I9, the flanges I8 terminating a short distance below said stop lugs, and the portions of the stave therebelow being formed as a narrow shank 2Il. The lower end portion of the shank 20 is swagd to form a gripper jaw 2l having a serrated inner surface 22 which projects somewhat beyond the inner surfaces of the shank, and an outer wedging surface 24 which flares outwardly from the shank 20 and merges at its upper limit into a shoulder portion 25 which slopes outwardly from the shank 23 somewhat more abruptly.

A plurality of such stave members, three in the example illustrated, are assembled in complementary relationship so that their portions IB and II cooperate to form a hollow receptacle which constitutes the magazine for the pencil, as illustrated in the cross-sectional view of Fig. 6. The ange portions I I are of such width and extend at such angular relationship' from the arched portion I@ that they meet those of the associated staves before the' margins of the wider arched portions l@ meet eacli other and hence, when the three staves are pressed together, the ilange prtions l l are placed under stress when the margins of the portions I 0 are brought together, and in this tensioned condition the flanges II continue to tend to press the staves apart. The three staves are held in their assembled complementary relationship by a ferrule 26 and by a collar 21, the former being telescoped onto their upper ends, thus holding the flanges II in their tensioned condition, and the collar 21 being passed over the lower ends of the staves and onto the clamp- /ing flanges I thereof until it abuts the lower ends of the flanges I4. The ferrule 26 and collar I 21 thus hold the margins of the stave portions I0 in contact with one another, and likewise the flanges I4 and I5 in engagement with one another, as illustrated in Fig. A'1. 'Ihus is formed a continuous tubular magazine with a conical bottom leading to a lead guide tube formed by the coin-A plementary arched portions I1 of the staves. When the staves are ilrst placed in their complementary relationship and before they are bound together by the'ferrule and collar, a illler cone 28 is positioned between their converging portions I2, thereby fllling the conical bottom of the magazine, where it .is retained in position by inwardly struck portions 29 oi' the staves. This filler cone 28 has its upper surface dished and it is formed with an axial bore 36 extending through it from top to bottom, which bore is of a size to pass a single lead stick at a time.

After being thus assembled, the slender gripper arm portions of the staves project in slightly divergent relationship below the lower end of the collar 21. A helical spring 3| is threaded onto them and its upper end portion is moved into encompassing relationship with the spring guide flanges I6 so that the upper end of the spring is engaged against thelower end ofthe collar 21 and the ends of the flanges I4. A washer 32 is then threaded onto the lower ends of the gripper arms which are pressed close to one another to permit their being inserted through a central aperture in the washer, which aperture is of size to receive the arched portions I1 oi' the arms loosely and has radially extending notches 34 arranged to pass the ilanges I 3 and stop lugs I9 of the three arms when those of juxtaposed arms are against one another.; 'I'he washer 32 has also a lug 35 projecting radially from its margin in offset relationship to the notches 34. A guide bushing 36 is then threaded upon the lower end portions of the gripper arms. This bushing has an external shoulder 31 for seating. upon a shoulder within the pencil barrel, and its lower end portion 36 is externally threaded for engagement with the pencil tip. The upper end of the bushing is c'ounterboredto receive the washer 32, and the bushing is provided with an axial bore which is stepped to provide an upper stop shoulder 39 vand a lower stop shoulder 40, and for a distance from its upper end the wall of the bushing is provided with a longitudinal slot 4I extending radially through it to the bore. The upper portion of the bore, which is of the smallest diameter, is wide enough to receive the gripper armsloosely, including four of the lugs I9 when the remaining two adjacent lugs are inserted at the upper end of the slot 4I After the arms have been slid longitudinally through the restricted upper portions of the bushing bore to an extent such that the stop lugs I9 are brought to a position below the upper stop shoulder 39, the lugs I9 which were traveling in the slot 4I may 'be moved inwardly from the slot, and then the bushing may be rotated on the arms to position all of the lugs I9 below the shoulder 39. The washer 32 is'rotated with the staves until its lug 35 is brought into alignment with the slot 4I, whereupon the washer may seat in the counterbored upper end portion of the bushing. This engagement of the lug 35 in the slot 4I holds the washer 32 against rotation relative to the bushing 36, while the engagement of the flanges I8 in the notches 34 of the washer holds the assembled staves against rotating relative to the washer 32 and bushing 36. The spring 3| is compressed longitudinally to some extent incidentto this assembly of the bushing 36 with the other parts, and it is retained in this partially compressed condition between the collar 21 and the washer 32, and the bushing 36v is retained against withdrawal from thegripper arms bythe engagement of the stop lugs I9 against the upper stop shoulder 39, but the bushing may b'e slid upwardly along the gripper arms against the pressure of spring 3 I'.

A clamping collar 42 is then threaded onto the lower ends of the gripper arms. This clamping collar is of external diameter such that it ts slidably in the enlarged lower portion of the bore of the bushing 36, whereby it is guided in coaxial relationship with the bushing. The clamping collar has an axial bore of diameter sufficient to accommodate the gripper shanks 40 when they are in their outward or divergent position, but upon retraction of the jaw portions 2| into the lower end of the clamping collar 42, said jaw portions 2| are wedged inwardly by the wedging action of. the clamping collar upon the diverging shoulders 25 and the more gently haring wedge surfaces 24. The stop shoulder 40 of the bushing provides an upper limit stop for the clamping collar 42 whereby it is held stationary to permit the retraction of the gripper jaws into its lower end, and, by the wedged engagement of the jaw surfaces 24 in the bore of the clamping collar, the latter is held so that it is moved forwardly in the bushing 31 by forward movement of the jaws.

In the ferrule 26 is secured 'a gauge member 44 which closes the upper end of the magazine excepting for a gauge opening 44a which is of width to admit lead sticks of the maximum diameter that the pencil is designed to use, and a cap member 45 is removably mounted in the upper end of the ferrule 26 in such fashion that aportion oi' it is held projecting thereabove. This cap member carries an eraser 46, and the cap member is reversible so that it may be mounted in the ferrule either in the position in whichv the eraser is housed in the latter, as shown, or in an inverted position wherein the eraser projects beyond the upper end of the ferrule.

' upper portions of The mechanism comprising the parts above mentioned may be completely assembled in the manner above described so that it may be inserted as a unit within the tubular barrel 41 of the pencil. This barrel is provided with an internal shoulder t8 upon which the shoulder 31 of the bushing 3G seats, the position of the shoulder 48 being such that the threaded end portion 38 of the bushing projects beyond the lower end of the barrel. The bushing :il fits the bore of the barrel in such fashion that the bushing is maintained in coaxial position therein. The pencil tip di? is screwed onto the end portion 38 of the bushing, the upper end of the tip abutting the lower end. of the barrel and holding the bushing et xedly mounted therein. The tip is formed with an internal shoulder El! which forms a forward or lower limit stop for the slidable clamping collar d?, and

has an axial bore which in its upper portion is of sufficient diameterto receive the 'jaws 2i when they are in divergent relationship beyond the lower end of the clamping collar. In the lower portion of the tip bore is mounted a lead retaining member 5I adapted to permit passage of a lead stick of the intended size, which retaining member has resilient portions adapted to grasp the lead stick w as to hold it frctionally against falling through the end orifice of the tip. With the pencil thus completely assembled, the mechanism is maintained in coaxial relationship with the barrel, the bushing 36 being retained in fixed position therein and the ferrule te, magazine, lead guide tube, gripper arms and clamping collar- 42 being reciprocable longitudinally in the barrel,

the upper portion of the ferrule having guiding i bore wall of the barrel as cooperation with the at 52., Accordingly, by holding the barrel stationary and pressing downwardly upon the projecting portion of the cap 65, the reciprocable parts may be moved downwardly or forwardly in the barrel against the pressure of spring 3i, and upon release of the pressure on the cap, said parts will'A be returned upwardly or rearwardly to the limit position. When there is no lead stick between the jaws 2i, the upperlimit position is tween them. When the pressure is removed from lli lill

established by engagement of the stop lugs i@ against the shoulder 39, as shown in Fig. l

To load the pencil for operation, the cap member 45 is completely withdrawn and sticks of lead are charged into the magazine throughy the gauge opening 44a and the cap member is then put back in place. With the pencil held with its point downwardly, one of the lead sticks will pass from the magazine through the bore 30 of the filler cone 28 portion the inwardly projecting gripping surface 22 of the jaws. The reciprocable portions of the mechanism then being pressed downwardly by pressure against the cap 45, the clamping collar 42 will be carried downwardly by the jaws until its lower end engages the stop shoulder 5l, whereat its forward movement is arrested. The continued downward movement of the other portions, which is 'arrested only when the ends of the flanges Il come into engagement with the upper end of the ,clamping collar 42. moves the jaws downwardly beyond the lower end of the clamping collar, thus freeing them of its constraint and permitting them to v and into the lead guide i1 until it is brought to rest against the l the cap 45, the reciprocable parts are returned upwardly by the spring 3l, the jaws engaging the lower end of the clamping collar 42 and carrying, it upwardly ahead of them, the jaws thus remaining-in their open or cast of! position and free of the lead stick until the upper end of the clamping collar is stopped against the shoulder N of the bushing $6, whereupon, with the continued upward movement of the magazine and jaws, the latter are wedged inwardly as they are drawn into the clamping collar, with the result that they are, swung into gripping engagement with the lead stick. With the `lead stick so gripped between the jaws, the upward movement" of the parts is arrested before the stop lugs lli reach the shoulder 39. vThe lead stickv being thus held securely gripped by the jaws under the constraining action of the clamping collar d2, the reciprocable parts are again moved downwardly by pressure on the cap l5 and the lead stick is positively propelled downwardly and forced through the resilient retaining member 5I. Thereafter, repeated operation of the reciprocable parts in the manner above described will be effective to feed the lead stick step by step, the length of feed at each operation being determined by the distance which the jaws move between their upper position of rest and the point at which they are freed from the constraining action of the clamping collar and permitted to move outwardly to disengage the lead stick. As the lowermost lead stick is thus fed forwardly step by step, a succeeding lead stick passes from the magazine and follows along by gravity until it reaches a position where it is engaged by the jaws. Thence it is fed forwardly step by step in the manner above described. propelling the short remaining portion of the preceding lead stick ahead of it. Accordingly, all of the lead sticks in the magazine may thus be fed successively to the writing point, step 'by step, by a series of successive operations of the reciprocable parts in the manner above def scribed.v

stock. yMoreover` the fabrication of those parts may be accomplished rapidly by pressing operation, thus eliminating relatively delicate operations such as are involved in the slitting of small tubes to form the gripping arms and jaws. Moreover, this stave construction provides a sheet metal lead guide tube in which the wall segments have slight inward'and outward movement relative to one another, which has the eiect of aiding the movement of the 'lead sticks by gravity, in that it reduces the likelihood of a sticks being stopped in the slender guide tube above the jaw Shanks. This stave construction also reduces the likelihood of the slender guide tube becoming bent, because the individual segments of the tube, and hence the tube as a whole. are very effectively stiffened by the anges i6 and Il. These several features are of definite advantage in obtaining certainty and reliability in the operation of the pencil, and another feature which contributes to the same end is the fact that tolerance variations which might affect the position of the jaws longitudinally in reference to the magazine and other associated misuse, as a new stave may be substituted for the one carrying the damaged jaw, thus per- Vmitting the pencil to be restored to operative condition without involving replacement of the other jaw and magazine portions. What I claim is:

1. In a mechanical pencil, a lead feeding member comprising a plurality of staves having upper portions associated in complementary relationship to form a tubular magazine for lead sticks and lower portions associated in complementary relationship to form a lead guide tube of smaller diameter than said magazine and leading from the end thereof, said lower portions having parts at their lower ends shaped to provide lead-gripping jaws.

V2. In a mechanical pencil, a lead feeding member comprising a plurality of st-aves having upper portions associated in complementary relationship to'form a tubular magazine for lead sticks and lower portions associated in complementary relationship to form a lead guide tube of smaller di-ameter than said'magazine and leading from the end thereof, said lower portions having parts at their lower ends shaped to provide lead-gripping jaws, and means retaining said upper portions of the staves in fixed. association, said lower portions being susceptible of limited flexing movement toward and from one another.

3. In a mechanical pencil, a lead feeding member comprising a plurality of staves having upper portions associated in complemenetary relationship to form a tubular magazine for lead sticks and lower portions associated in complementary relationship to form a lead guide tube of smaller diameter than sai-d magazine and leading from the end thereof, said lower portions having parts at their lower ends shaped to provide lead-gripping jaws, said lower portions having outwardly deiiected parts extending longitudinally of them.

4. In a mechanical pencil, a lead feeding member comprising a plurality of staves having upper portions associated in complementary relationship to form a tubular magazine for sticks and lower portions associated in complementary relationship to form a lead guide tube of smaller diameter than said magazine and leading from the end thereof, said lower portions having parts at their lower ends shaped to provide lead-gripping jaws, said lower por-tions having outwardly deflected marginal anges extending longitudinally of them.

5. In a mechanical pencil, a lead feeding member comprising a plurality of staves having upper portions associated in complementary relationship to form a tubular magazine for lead sticks and lower portions associated about a common axis to form a lead guide tube of smaller diameter Ithan said magazine and leading from the end thereof, said lower portions having parts at their lower ends shapedv to provide lead-gripping jaws, said lower portions being resilient and tending to spring outwardly from one another.

6. In a mechanical pencil, a lead feeding member comprising a plurality of staves having upper portions associated in complementary relationship to form a tubular magazine for lead sticks and lower portions associated in complementary relationship to form a lead guide tube of smaller diameter than said magazine and leading from the end thereof, said lower portions having parts at their lower ends shaped to form resilien-t outwardly-springing shanks carrying lead-gripping Jaws.

lead

having parts at their lower 7. In a mechanical pencil. a lead feeding member comprising a plurality of staves having upper portions associated in complementary relationship to form a. tubular magazine for lead sticks and lower portions associated about a common axis to form a lead than said magazine and leading from the end thereof, said lower portions having parts at their lower ends shaped to provide lead-gripping jaws, said lower portions having outwardly deected marginal flanges extending longitudinally of them and carrying stop lugs projecting beyond said flanges.

8. In a mechanical pencil, a structure as speciiied in claim 1 and wherein sai-d upper portions are connected to said lower portions by downwardly tapering portions.

9.' In a mechanical pencil, a lead feeding member comprising a plurality of staves having upper portions associated in complementary relationship to form a tubular magazine for lead sticks and lower portions associated in complementary relationship to form a lead guide tube of smaller diameter than said magazine and leading from the end thereof, said lower portions having parts at their lower ends shaped to provide lead-gripping jaws, a removable ferrule binding said staves together at their upper ends and a removable collar binding them together at the lower ends of said upper portions.

10. In a mechanical pencil, a lead feeding member comprising a plurality of staves having upper portions associated in complementary relationship to form a tubular magazine for lead sticks and lower portions associated in complementary relationship to form a lead guide tube of smaller diameter than said magazine and leading from the end thereof, said lower portions ends shaped to provide lead-gripping jaws, a removable ferrule binding said staves together at their upper ends and a cap member mounted on said ferrule and extending beyond its upper end, whereby pressure may be transmitted to the staves to move them longitudinally as a unit.

11. In a mechanical pencil, a lead feeding member comprising a plurality of staves having upper portions associated in complementary relationship to form a tubular magazine for lead sticks and lower portions associated in complementary relationship to form a lead guide tube of smaller diameter than said magazine and leading from the end thereof, said lower portions having parts at their lower ends shaped to provide leadgripping jaws, juxtaposed staves having at their upper ends laterally deflected resilient parts in engagement with each other, and a ferrule binding said staves together with said resilient parts in stressed condition.

12. In a mechanical pencil, lead feeding mechanism including a plurality of resilient gripper arm portions arranged around a common axis and individually movable toward and from same, stop lugs extending outwardly from said gripper arm portions, a washer centrally apertured to permit passage of said gripper arm portions and their stop lugs and to retain it against rotation relative to them. a bushing having a bore with an jutting shoulder and a radial slot ing from one end to l a point beyond said shoulder, said bore being formed to pass said gripper arm portions and stop lugs when certain of the latter are positioned in said radial slot,

guide tube of smaller diameter inwardly.

extendand means for retaining said washer in coaxial relationship with said bushing and against rotation relative thereto withv said stop lugs3 in positions to engage said shoulder.

13. In a mechanical pencil, lead feeding mechanism comprising a bushing having an axial bore with. an inwardly jutting shoulder and a lateral slot extending into the bore from one end of the bushing to a point beyond said shoulder, a plurality of gripper arm portions arranged around a common axis and having laterally projecting stop lugs, said gripper arm portions being movable longitudinally into said bore when certain of said lugs are in said lateral slot, and means for retaining said bushing against rotation relative to said gripper arm portions when said stop lugs are positioned in the bore and out o alignment with said slot.

14. In a mechanical pencil, a structure as specified in claim 13 and wherein said gripper arm portions are resiliently movable toward and from the common axis.

15. In a mechanical pencil, a structure as specified in claim 13 and wherein said gripper arm portions are resiliently movable toward and from the common axis, and means in the bushing for constraining said gripper arm portions toward said axis.

16. In a mechanical pencil, a structure as specified in claim 13 and including spring means -eiective on said gripper arm portions and said bushing to press said stop lugs toward said shoulder. f

17. In a mechanical pencil having a magazine adapted to contain a plurality of lead sticks side by side, a lead guide tube leading from the magazine and having a bore of size to pass a single lead stick, said lead guide tube being formed of segments arranged around a common axis and having limited movement individually toward and from the same.

18. In a mechanical pencil, a lead feeding mechanism comprising a plurality of identical staves having complementaryportions associated

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