US1724173A - Lead pencil - Google Patents

Description

Aug. 13, 1929. B. c. BECKER LEAD PENG IL Filed July ll, 1921 @am s;

Z7 INVLNTOR.

Patented Aug. 13, 1929.

UNTTED STATES PATENT OFFICE.

BERNARD C. BECKER, F ROME, NEW- YORK, ASSIGNOR TO THE YODER PENCL CUM- PANY, 0F CLEVELAND, OHIO, A CORPORATION `Oli' OHIO.

LEAD PENCIL.

Application led July 11,

This invention relates to a lead pencil oli the type wherein the lead is supported in a tubular point and is moved outward by the action ot a push rod.

rlhe object ot this invention is to provide a lead gripping device lior setting up resistance against lengthwise movement ot the lead, particularly one which can be embodied within a. small slender tube; and turther one which can be arranged to effect a greater or less resistance to lengthwise movement ot the lead as conditions may require.

A. further object is to provide a pencil ot the character set 'forth on which a long slender tubular point may be employed, so that better vision may be had to the writing. This is accomplished through the small and compact means which l employ lor pre venting the lead from moving` ahead ot the movement ot the push rod.

lilith these and other objects in view this invention consists of certain novel 'features' as hereinafter shown and described, and

then specifically pointed out in the claims.

The practical embodiment ot this invention is represented in the accompanying drawing forming a part ot this specification, and

in which similar numerals refer to similar parts throughout the several views.

Figure l is an elevation of a pencil embodying my invention.

Fig'. 2 is a longitudinal sectional view taken on line 2-2 ot Fig. 1.

Fig. 3 is an enlarged fragmentary view ot the point of the pencil.

Fig. 4 is a longitudinal sectional view of a pencil point. being a modification ot the ioint shown in Fig. 2, at A.

Fig. 5 is a detail view ot the tube B shown in Fig. 4.

Figs. 6, 7 and 8 are enlarged sectional views showing modifications ot the shape of the spiral groove which may be employed in the construction ot the point shown in Fig. 2, at A.

Fig. 9 is a| detail drawing of a part ol' the mechanism tor propelling` the lead.

Fig. l() is a plan view of Fig. 9.

Fig. 11 is a detail drawing ot the end ot' the pencil which holds the eraser.

Figs.y 12, 13 and 14C, represent modifications o't the point construction shown at A, Fig. 2.

With reference to the drawing, l is the resi. serial No. 483,738.

handle of the pencil. 3 is a tubular casing fitting over the end of the handle l and firmly tixed thereto by solder or otherwise, and in conjunction therewith forms a magazine l tor carrying a surplus store ot leads. 5 is an eraser litted into the end of the tubular casing 3, the end ot this casing being threaded as shown at (l, reduced in diameter as shown at 7, and beveled as shown at 8;

short. the same may be extended to proi' trude the original distance by unscrewing the sleeve on the thread (5, thereby releasing the clamping action ci' the spring ends 11 upon the eraser, after which the eraser may be adjusted as desired and again clamped to hold it lirmly in position. rThe sleeve 10 is hnurled as shown at 18.

The tubular point A is mounted in the handle 1 at 141- in a manner tree to rotate. ln this tubular point is carried the lead 15 as shown. Fixed to t-he tubular point A or forming a part thereof, are two guide strips 16 which guide lengthwise movement ot" the cross head 17 and cause the same to rotate in unison with the tubular point A. These guide strips are joined together at the up` per end as shown at 18. rlhe threaded screw 19 carried by the end 18 ot the guide strips. Between the threaded screw 19 and the end 18 ot the guide strips is a washer 20. A pin 21 is fitted in the end 18 of the guide strips and through the washer 20, to assure that they both rotate together and prevent loosening the screw 19. The washer is carried in the recess 31 ot the handle 1 and terms a bearing for the end 18 ot the guide strips.

The cross head 17 is tree to slide between the guide strips 16, and carries a push rod 22 which is tree to slide in the tubular point A. The handle 1 is provided with an internal thread 28 which is adapted to engage with the teeth 24 on the cross head 17. The tubular point A is provided with a lmurled collar 25.

The operation of this mechanism is as follows: The handle 1 is held in the right-hand as is natural when writing, and the tubular point A is turned by the left-hand, gripping the same by the knurled collar 25. This causes the cross head 17 to rotate relative to the handle 1 through the action of guide strips 16. It is apparent that rotation of the cross head 17 relative to the handle 1 will cause the same to move lengthwise in the pencil, and carry with it the push rod 22.

his in turn pushes the lead 15 forward in the direction indicated by the arrow 26, and the end 27 ofthe lead may be adjusted to project beyond the end of the tubular point A as desired.

Vhen the pencil is not in use, the end 27 of the lead may be protected from breaking, by turning the tubular point A in the proper direction for moving the push rod 22 back into the pencil, after which a slight pressure on the end 27 of the lead will cause the same to move inward until it is liush with the end of tile tubular point A where it is safely protected. y

To avoid the possibilit-y ofthe point A turning accidentally Awhile writing, l provide a friction device comprising a circular spring 28, normally having a shape as shown in Fig. 10; it is carried in the groove 29 which is formed in the washer 20. The end of the spring 28 is bent over and tted into a hole 30 formed in the washer 2O to assure that the spring will rotate therewith. A recess 31 is provided to incase the washer 20 and spring 28 and the normal tendency of the spring 28 to expand and accordingly contact with the inner surface thereof will pioduce a resistance to rotation of the tubular point A relative to the handle 1, due to the friction between the spring 28 and the inner wall of the recess 3 1. By properly proportioning the spring 28 the tubular point A will be free enough to be rotated by hand but will not rotate accidentally.

Referring to Fig. 3 which is an enlarged view of the end of the tubular point A shown in Fig. 2. 32 is a spiral spring which is fitted around the lead 1,5 and into the spiral lgroove 33. The normal internal diameter of the spiral spring 32 is slightly less than the diameter of the lead 15, therefore the spiral spring will have a gripping action upon the lead so that it requires a slight effort 'to slide the lead 15 lengthwise through the spiral spring 32. rlhe object of this is to prevent the lead 15 from moving out of the tubular point A ahead of the movement of the push rod 22. A

It is obvious that with this construction any lengthwise movement of the lead 15 will not carry with it the spiral spring 32; for the reason that the spiral spring 32 will be held stationary by Ycoming in contact with one of the side walls of the spiral groove 33,

and also the lead 15 may be moved in either direction and will work equally well without causing damage to any of the parts by this procedure. 1t is also obvious that the spiral spring 32 produces a uniform gripping action all around the lead 15, and that this spiral spring 32 may have a long length, thereby providing a large wearing surface and long life.

Figs. (i, 7, 8 and 12 show modified shapes of the spiral groove shown at in Fig. 3. Referring to Fig. G, the side walls 34e. of the spiral groove are inclined. Vhcn in this form and when the lead is moved lengthwise, the spiral spring will wedge itself between one of the side walls and the surface of the lead 15. This wedging action increases the gripping pressure of the spring 32 on the surface of the lead 15, which in turn increases the efforts required to move the lead.

. If the side walls of the spiral groove 33 are perpendicular to the surface of the lead 15 as shown in Fig. 3 at 3G, there is no wedging action as above described, and the only el'ort required for moving the lead l5 lengthwise through the spiral spring 32, is that which is necessary to overcome the inherent gripping action of the spiral spring.

Referring to Fig. 8 in which only one of the side walls of the spiralA groove is inclined as shown at 34. This construction gives an elliect whereby the lead may be easily moved lengthwise in one direction, but it will require more ellfort to move the lead in the opposite direction; this being apparent for the reason that wedging action does not occur on the spiral spring when the lead is moved in the direction indicated by the arrow 35; but it does occur when the lead is moved in the opposite direction, and in the same manner as above described relative to Fig. 6.

Referring to Fig. 7, in which the bottoni surface 37 of the spiral groove 33 is formed at an angle with the surface of the lead l5. lith this form the results obtained are practically the same as that described relative to Fig. 8, except that the wedging action et the spring 32 is somewhat greater, because the angle formed by the surfaces between which the spring wedges is less; this can readily be seen by comparing the angle iudicated by 38 to the angle indicated by 39. The comparative result obtained by the constructions represented in Figs. 7 and 8 is that in both cases the effort required to move the lead lengthwise in the direction indicated by the arrow 35 is the saine, but in the construction shown in Fig. 7 the eilort required to move the lead in the opposite direction will be considerably more than that required with the construction shown in Fig. 8.

t is obvious that with these various lll) shapes for the spiral groove 33 or by com# biningsuch shapes to form a spiral groove, the pencil may be constructed so that the effort required for moving the lead 15 lengthwise may be controlled as desired.

A further improvement may be had by consti-noting the spiral spring 32 of a wire having a sectional shape substantially the same as the various shapes shown and described for the spiral groove 33, or more especially by making the surface of the spiral spring 82 which comes in contact with the surface of the lead 15 equal to substantially the full width of the spiral groove 33, thereby increasing the wearing surface be` tween the spiral spring 32 and the lead 15; this also provides better support for the lead 15. One form of this construction is represented in Fig. 12, in which the spiral spring 32 is formed of a wire having a square cross sectional shape to correspond to the shape of the groove 33.

Obviously it is a difficult mattei' to cut a spiral groove like that shown at E33 in the end of the tubular point A, on account of the hole through the tubular point necessarily being small to fit the lead. To facilitate the forming of the spiral groove 33 in the tubular point A, I prefer the modified construction as shown in Fig. 4, wherein the tubular point A is counterbored as shown to lit the tube B. The end of the tube B is formed as shown in Fig. which represcnts a tube having an internal diameter to ht the lead with the wall thereof cut through spirally as indicated by 41. When this tube is placed into the tubular point A as shown in Fig. 4 it produces a spiral in tei-nal groove which is practically the same as that shown in Fig. 3.

All other matters concerning this invention and which are herein shown and described have the same application with this modified construction as with the construction shown in Fig. 3.

ln the modified form Fig. 4 the thread 42 is formed on the tubular point A as shown, and fitted into the knurled collar 25. 43 is a hole into which a spanner Wrench may be inserted for unscrewing the tubular point A from the knurled collar 25, under which conditions the tube B may be removed, carrying with it the .spiral spring 32.

I have found that, for a simplified construct-ion although not entirely as satisfactory, the spiral spring 32 may be eliminated; under this condition the spiral groove 33 nally becomes lled vwith graphite which is scraped from the lead by the sharp edge formed by the groove, in conjunction with the wall of the hole; this graphite finally packs in sufficiently tight and builds up to an extent whereby it fits neatly around the lead, causing suliicient resistance to movenient of the lead and prevents the same from moving ahead of the movement of the push rod 22.

It is apparent that under such circumstances it is not necessary that the groove 33 should be a spiral, it would then be immaterial whether or not it comprises a spiral groove or merely a series of circular grooves 46 formed around the inside of the wall of the hole, as represented in Fig. 14.

Another modified construction would con sist of forming a groove, or series of grooves around the inside of the hole, and placing therein a contractile spring ring 44, Fig. 13; such ring being preferably constructed of wire bent in circular fashion, with its ends abutting against each other; the internal diameter of the ring being sufficiently small so it just grips the lead but such ring being yieldable so that the lead may be forced through the ring.

The principle involved' in this construction is practically the same as that wherein the spiral spring 32 is used, t-he difference being merely that of construction which exists between a wire ring 44 of circular form, and a spiral spring as shown at 32. It is obvious that the saine difference would necessarily exist between the formation of the grooves, in one form the groove is spiral at 33; in the other it is circular as at 4G.

In manufacturing such construction, it is obvious that substantially the same scheme may be employed for forming the circular .shaped groove in the hole, as that shown in Fig. 4, the difference merely being in forming the end of the tube B. lt would then not be permissible to cut the wall of the tube through spirally as shown in Fig. 5, but instead the tube should be cut squarely oil'I as shown in Fig. 13, and a series of spacing washers 45 should be placed between the wire rings 44; these spacing washers being arranged to perform the same function as the spirally formed end of the tube B as shown in Fig. 5.

An important feature in connection with this invention is the possibility of a long slender point; whereby excellent vision may be had to the writing, and it also provides a means whereby the end of the push rod 22 may be rapidly adjusted to the location desired. As the pencil is ordinarily used it is held in the right hand by the handle 1, and the knurled collar 25 is rotated between the thumb and forelinger of the left hand for making slight adjustments of the push rod; but when it is desired to rapidly move the push rod for a considerable distance, for instance, from an extreme forward position to the extreme rear position so that a new lead may be inserted into the end of the tubular point A, then such rapid movement accomplished by rotating said tubular.'

- ent, is as follows l. In a lead pencil, the combination of a tube capable of carrying a lead and having a spiral groove in the material which forms the wall of the hole thereof, and a spiral spring in said spiral groove.

2. In a lead pencil, the combination of a tube capable of carrying a lead and having a spiral groove in the material which forms the wall of the hole thereof, and a spiral spring in said spiral groove, said spring being arranged so that the internal diameter thereof is normally smaller than said hole, and sufliciently yielding to permit expansion thereof until said internal diameter is substantially equal to the diameter of said hole.

3. In a lead pencil, the combination with a tubular point, of a tube within said tubular point, the end thereof terminating to a spirally formed filamentary body arranged to form a spiral groove within said tubular point, and a spiral spring in said spiral groove.

4. In a lead pencil, the combination with a tubular point, of a spirally formed filamentary body within said tubular point and arranaged to form a spiral groove, and a spiralspring in said spiral groove.

5. In a lead pencil, the combination of a tube capable of carrying a lead, a spiral groove in said tube, and a spiral spring in said groove, said spring being arranged to wedge between the wall of Said groove and the surface of said lead when said lead is moved lengthwise in said tube.

6. In a lead pencil, the combination of a tube, a spiral groove in said tube, a push rod adapted to move lengthwise in said tube, and a spiral spring in said groove, said spring being arranged to wedge between the wall of said groove and the surface of said push rod when said push rod is moved lengthwise in said tube.

7. In a lead pencil, the combination of a tube capable of carrying a lead and having a groove in the material which forms the wall of the hole thereof, one wall of said groove being at an angle with the surface of said lead, and a contractile spring in said groove, said spring being arranged to wedge between said angular wall and the surface of said lead when said lead is moved lengthwise in said tube.

8. In a lead pencil, the combination of a tube for supporting a lead and formed on its inner wall with a groove, one wall of said groove being at an angle with the central axis of said hole, a push rod adapted to move lengthwise in said tube, and a contractile spring in said groove, said spring being arranged to wedge between said angular wall and the surface of the lead and said push rod when said push rod is moved lengthwise in said tube.

9. A lead pencil point comprising a lead carrying tube suitable for guiding the lead through lengthwise movement and having a groove in the material which forms the wall of the hole thereof, said groove being arranged to circumscribe said hole.

l0. In a lead pencil, the combination of a tube capable of carrying a lead and having a groove in the material which forms the wall of the hole thereof, said groove being arranged to circumscribe said hole, and a contractile spring in said groove, said spring being arranged so that the internal diameter thereof is normally smaller than said hole, and sufficiently yielding to permit expansion thereof until said internal diameter is substantially equal to the diameter of said hole.

ll. In a lead pencil, the combination of a tube capable of carrying a lead and having a groove in the material which forms the wall of the hole thereof, and a contractile spring in said groove.

12. In a lead pencil point, the combination of a tube for receiving a lead and having an internal spiral groove, and means in the spiral groove for retarding movement of the lead through the tube.

In testimony whereof I have signed my name to this specification.

BERNARD C. BECKER.

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