US2511301A

US2511301A - Mechanical pencil

Info

Publication number: US2511301A
Application number: US634271A
Authority: US
Inventors: Blanchard D Smith
Original assignee: Scripto Inc
Current assignee: Scripto Inc
Priority date: 1945-12-11
Filing date: 1945-12-11
Publication date: 1950-06-13
Anticipated expiration: 1967-06-13

Description

June 13, 1950 B. D. sMxTH MECHANICAL PENCIL 2 Sheets-Sheet l Filed Deo. 1l, 1945 INVENTOR. llurd.fmi

June 13, 1950 B. D. SMITH MECHANICAL PENCIL 2 Sheets-Shet 2 Filed Dec. 1l, 1945 ml/ MMM l l m a7 fj Z7 if? 44/ Patented June 13, 1950 UNITED STATES PATENT OFFICE MECHANICAL PENCIL Blanchard D. Smith, Atlanta, Ga., assignor to Scripto, Inc., a corporation of Georgia Application December 11, 1945, Serial No. 634,271

15 Claims. (Cl. 12018) The invention relates to mechanical pencils and has as an object the provision of the improvement o1' the propel, repel mechanism with particular reference to the lead expelling means.

It is an object of the invention to improve the lead expelling means, the nut, clutch and the split tube revolving member.

It is a further object of the invention to provide a pencil which will be simple of production and assembly.

It is a further object to provide a pencil having eicient means for application of a clasp to the pencil structure.

Further objects will appear from the following description when read in connection with the accompanying drawing showing an illustrative embodiment of the invention and wherein:

Figure 1 is a side elevation partly in vertical section and drawn to an enlarged scale, the showing being cut away to shorten the View;

Fig. 2 is a central Vertical section taken at an angle of 90 to the sectional portion of Figure 1;

Fig. 3 is a horizontal section on line 3-3 of Fig. 2;

Fig. 4 is a horizontal section on line 4-4 of Figure 1;

Fig. 5 is a View similar to Fig. 2 of a different position of the parts certain of which are shown in elevation; y

Fig. 6 is a detail perspective view of a split tube of the invention broken away to shorten its length;

Fig. 7 is a detail horizontal section on line 'l-'I of Fig. 5;

Fig. 8 is a side elevation of a winged plate;

Fig. 9 is a detail perspective view of the clutch;

Fig. 10 is a like view of the nut;

Fig. 11 is a detail plan of a split tube blank; and

Fig. 12 is a transverse section on line I2-I2 of Fig. 2.

As shown, the device comprises a barrel member I5, internally threaded as at I5, and shown as formed with multiple screw threads, three in number, as will be seen from an inspection of Fig. 3.

The pencil also comprises a split tube I1, a nut I8 and a clutch i9. The nut is shown as formed with an annular member having its exterior surface formed with screw threads 2|, complemental to the screw threads I6 and also formed with an internal rib 22 widened below annular member 2l] as at 23 and carrying integral therewith a lead propelling member 211. The bottom end of the rib member 23 is shown as rounded as at 25 for a purpose to be described,

, The annulus2l) surrounds the split tube as indicated in Figs. 1 to 3 inclusive and 5, while the rib 23 resides in the split of the tube with the round member 24 standing internally of the tube and clutch as clearly indicated in Fig. 4.

The clutch member I 9 is shown as formed with a resilient cylindrical split portion 2B which clasps the lead 2l as indicated in Fig. 2 and the split of this tube is successively widened as at 28 and 29, Fig. V9. The space between the edges of the material lforming the clutch, in the widened portion 28 is suiiicient to allow free reciprocation of the rib 2i) therein in the expelling action of the clutch and as shown in Fig. 4. The width of the space at 29 is substantially twice that at 28 whereby when the rib 23 stands in the space 2i), as in the writing and lead feeding position shown in Fig. 3, the end 24 of the lead expelling portion of the rib 23 ofthe nut will overlie the cam lug 35 to be described. The upper portion of the material of the clutch I9 is severed as at 30, 3| and the freed portions are bent inwardly as shown at 32, 33 which portions overlie the upper surface 34 of the member 24 of the nut as clearly indicated in Fig. 2. Therefore when the nut is moved to retract, or provide the repelling motion of the nut, the clutch will be forced upwardly in the split tube.

To provide the propelling movement of the clutch the lower portion of the clutch wall at the lower end of the widened split 29 is shown as freed and turned outwardly to form a cam lug 35 which normally underlies the end 25 of the rib 23 of the nut as clearly shown in Fig. 5. This position of the parts which is shown in side sectional view in Fig. 2 is the normal position of the parts during writing of the pencil and feeding or retracting the lead therein.

One side of the split tube I1 is shown as cut away at 36. When, in the feeding of the lead, the clutch I9 reaches the position shown in Fig. 1 wherein the end of the clutch rests against a shoulder 31 near the point of the pencil, and when the clutch resides in a slight enlargement 38 of the bore above the lead feeding opening 39, the clutch is prevented from further downward movement and the rounded end 25 of the rib 23 coacts with the cam lug 35 to cause this lug to revolve the clutch, the lug escaping from the slot of the tube I1 into the recess provided by the cut away portion 3B, into the position shown in Figure 1. y

Further movement therefore of the nut from the position shown in Figs. 2 and 5 will cause the end 34 to move away from the

wings

32, 33 and cause the portion 24 to push the lead out of the clutch, the final position of the parts being as shown in Fig. 1. The nut may then be retracted until the shoulder 34 again contacts the

wings

32, 33 at which time the end 25 will be above the lug 35, and upward movement of the clutch will cause the lug 35 to cam against the cut away surface 36 to swing the parts back to the normal position of jFig. 5, whereupon a new lead may be forced into the clutch.

To cause revolution of the split tube Il relative to the barrel, a winged plate member 40 is shown indicated in detail in Figs. 7 and ,8, As there shown, a disk portion 4l is provided with a substantially circular opening 42 to receive the projection 43 upon the end of the split tube Il.

As shown, particularly in Fig. 6, the Split tube is formed with partially

circumferential slits

44, 45, and 46, and with longitudinal slits 4i and 48. The member 4U is shown as formed with an inwardly projecting lug ile projecting into opening 42. At the ends of slits 4l and 48 short circumferential slits are provided as shown in Fig. 11.

In assembly the arcuate portions released by slits i4 and 48 are bent outwardly to provide wings im and wings similar to those shown at 4l', and'caps 5c and plate 4i' are placed over the thus bent out wings. The portions freed above slits 6 and 4l are then bent outwardly to provide the wings 5i, 52. The material of the tube at each side of slit 4l also flared outwardly to prei/.ide the. wines 4.1' and with the wines 5|. 5.2 serves to hold the parts in assembly with the tube while the lug 4.9 forces the tube to revolve with cap 4|.

The Side Walle ef the Cap 56 are indented inte recesses e4 te prevelitrevelutien of the cap 1.111.011 the barrel er removal therefrom and to. re.- the ririe et which iS integral with the boeket clip 56.-. The Winged plate 4Q ie Shown es formed with three, Wines. 56. l. 5.8 whichy hue the cap member te. aet a brake, against undue revolution of the split tube. The remaining wings 5S, 50. 6i flare outwardly to press against the interior of the cap 62 to transmit rotation of the cap to the tube. The cap or ferrule t2 carries the eraser thimble at its openv end.

It will be seen therefore that if the barrel I5 is held and the cap 52 is caused to revolve relative thereto the split tube will be revolved and the lead will be actuated to propel or repel the same. Because of the frictional means for causing such relative revolution, when the lead is iinally expelled and the, clutch cannot move further, continued forced revolution of the cap 62 will merely cause slippagey of the friction drive and no harm to the mechanism will result.

This application is filed as a continuation-inpart of my application, Serial No. 582,199, iiled March 12, 1945, now abandoned.

Minor` changes may be made in the physical embodiment of the invention within the scope of the appended claims without departing from the spirit of the invention.

It will be seen that the cap 50 functions as a connector in that it connects the split tube l'l to the barrel l5 by virtue of its coaction with the wings freed by

slits

44, 45 and by Virtue of its immovability with respect to the barrel. The wings 56-6l have only the functions of` driving the split tube, and braking movement thereof which'would otherwise be caused by writing thrust upon the lead.

I claim:

l. A mechanical pencil comprising, in combination: an internally screw threaded barrel; a split tube formed with a longitudinal slot revoluble in said barrel; a nut comprising an annular externally screw threaded portion having its screw threads engaging said internal screw threads, said annulus surrounding said split tube, and an internal rib standing in said slot; and a lead clutch slidably actuated by said nut in said split tube.

2. A mechanical pencil comprising, in combination: an internally screw threaded barrel; a split tube formed with a longitudinal slot revoluble in said barrel; a clutch member comprising a tube formed with a longitudinal slot and slidable in said split tube; a cam lug projection from said clutch member at one side of a portion of the slot thereof; a nut formed with a screw thread element in mesh with the internal screw threads of said barrel and with a rib slidable in the slots of the split tube and clutch and with an end overlying the position of a, lead held by said clutch; a shoulder carried by said nut normally overlying said cam lug to drive a lead in expel direction while applying turning stress to said cam lug resisted by an edge of the slot of said split-tube; said edge formed with a cut away portion to permit of such turning movement with consequent relative sliding movement between the nut and clutch.

3. The structure of claim 2 with the cut away portion in the edge of said split-tube slot at a location spaced from the pencil point end thereof.

4. The structure of claim 2 with a shoulder formed on said rib underlying a portion of the clutch structure to cause retraction of the clutch and a lead carried thereby when the nut is moved in a direction away from the pencil point end of the pencil structure.

5. The structure of claim 2 in which the thread bearing portion of the nut is an annulus surrounding the split tube.

6. A mechanical pencil comprising, in combination: an internally screw threaded barrel; a split-tube axially mounted in said barrel for relative rotation with respect thereto; a cap xedly carried by said barrel and rotatable relative to said split-tube; a second cap telescoped over the first named cap revoluble with respect to the barrel; friction means to cause said tube to partake of relative rotational movement between said caps and means coacting between the fixed cap and the barrel to prevent axial movement of said split tube.

'7. A mechanical pencil comprising, in combination: an internally screw threaded barrel; a split-tube axially mounted in said barrel for relative rotation with respect thereto; a cap xedly carried by s aid barrel; a second cap telescoped over the rst named cap revoluble with respect to the barrel; and means to cause said tube to partake of relative rotational movement between the second named cap and the barrel comprising a plate xed to said split-tube and having friction means engaging the inside of the second named cap and friction means engaging the outside of the first named cap respectively.

8. The structure of claim 7 in which the friction means include a split skirt on said plate providing a plurality of depending wings certain of which are expanded to frictionally engage the interior of the second named cap and others of which frictionally engage the exterior of the rst named cap.

9. A mechanical pencil comprising, in combination: an internally screw threaded barrel; a split tube axially mounted in said barrel for relative rotation with respect thereto; portions of the wall of the tube adjacent its end opposite the writing end freed by circumferential slits t provide wings to be bent outwardly; a winged plate having a lug projecting into the slot of said split tube to prevent relative movement therebetween, said plate supported by certain of said wings and retained by others thereof; an outer` cap member revoluble on said barrel and internally frictionally engaged by certain wings of said plate to cause revolution of said split tube to cause feed of lead from the tip of the pencil.

10. 'I-he structure of claim 9 with a cap nonrevolubly associated with said barrel, its head underlying said barrel, and overlying said bent out wings and frictionally engaged by certain other wings of said plate acting to stabilize feed motion of said split tube.

11. A mechanical pencil comprising, in combination: a barrel; a split tube axially mounted in the barrel for rotation relative thereto; means to move lead to writing position actuated by said relative rotation; a cap revoluble with respect to the barrel; means xed relative to said tube and having frictional engagement with said cap; and means xed relative to said tube and formed with frictional means to prevent relative rotation between said tube and barrel; the frictional engagement of the iirst named means exceeding that of the second named frictional means; whereby relative rotation of said cap 4and barrel will cause movement of the lead and movement of the lead by writing pressure will be prevented.

12. A mechanical pencil comprising, in combination: a barrel; a connector cap xed to said barrel, and formed with an axial opening; a split tube revoluble in said barrel; means carried by said tube respectively underlying and overlying the margin of said axial opening whereby to prevent axial movement of the tube relatively to the barrel; a sleeve revoluble upon said connector cap; friction means for transmitting mo- 4 tion of revolution of said sleeve to said split tube; and means actuated by revolution of the tube to cause propel of a lead housed in the barrel.

13. The structure of claim 12 in which said motion of revolution transmitting means is a disk locked with said split tube against circumferential motion relative thereto, said disk formed with a plurality of depending wings, certain of said wings having frictional engagement with said revoluble sleeve, and others thereof having frictional engagement with said connector cap; said winged disk having the sole function of controling motion of revolution of said split tube.

14. In a mechanical pencil of the type comprising a lead propelling mechanism housed in a casing and operated from a ferrule carried at the top end of the casing, an assembly cap ilxed on said casing at the top end thereof, said assembly cap being revoluble relatively to said propelling mechanism and being formed with a bearing surface adapted to carry said operating ferrule, and having an axial opening adapting said cap for retaining engagement with said propelling mechanism and allowing access to said propelling mechanism for operation from sai-d ferrule.

l5. In a mechanical pencil of the type comprising a lead propelling mechanism housed in a casing and operated by a ferrule carried by the top of the casing: an assembly-maintaining cap xed on said casing at the top end thereof; said assembly cap formed with an axial opening; propelling mechanism revolubly mounted in said casing and projecting through said opening; means carried by said propelling mechanism and underlying said cap to prevent axial outward movement of said mechanism from said casing; a ferrule telescoping with said cap and revoluble with relation thereto; and friction means coacting between said ferrule and said propelling mechanism to cause rotation of the latter when the ferrule is rotated.

BLANCHARD D. SMITH.

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

UNITED STATES PATENTS Number Name Date 1,574,393 Hofmann Feb. 23, 1926 1,716,953 Dunne June 11, 1929 1,956,271 Chesler Apr. 24, 1934 2,082,844 Meilner June 8, 1937