US2564727A - Mechanical pencil - Google Patents

Description

AugU 21, 1951 H. W. SAMS 2,564,727

. MECHANICAL PENCIL Filed April '7, 1948 (Ittornegs Patented Aug. 2l, 1951 MEonANroAL PENCIL Herbert W. Sams, Atlanta, Ga., assignor to Scripto, Inc., a corporation of Georgia Application April 7, 1948, Serial No. 19,469

This invention relates to mechanical pencils having a screw type lead feed mechanism. and more especially to an improved construction for pencils of this sort in which a novel form of ejector pin is incorporated which eliminates end play in the lead-feed, andin which the lead feed mechanism is otherwise arranged for assembly in the 'pencil so that particularly smooth operating characteristics are obtained. 1

Also, according to the present invention, the various-'elements of the pencil construction are arranged to insurealignment of the barrel-and the lead feed mechanism upon assembly.

. The present invention is described in detail below in` connection with the accompanying drawing, in which:v

v Fig. 1 is a vertical section of a mechanical pencil constructed in. accordance with the present invention;

.Fig. 2 is a section aken on the line 2-2 in Fig', 1; L.

Fig. 3 is a section taken on the linev 3 3 in Fig. 1;

Fig. 4 is an enlarged detail of the writing point of the pencil as seen from the right side inFig. 1 with the lead feed mechanism in full downward position.;

Fig. 5 is a detail of the ejector pin and lead grip sleeve;

Fig. 6 is a corresponding, partly right .sidefdetail .Y f

Fig. 7` is a sectional detail taken on the line 'll-'I in Fig. 5; and. 1

Fig. 8 is a fragmentary detail illustrating the manner in which the lead feed mechanism is assembled.

. [As shown in the drawing, the mechanical pencil of the present invention comprises a barrel vIt preferably formed of moulded plastic and having separate upper and lower portions I I and I2. The upper portion II of the barrel Iil serves as an operating cap, and may be iitted in any convenient manner with a pocket clip I3 if desired,.while the lower portion I2 provides an anchoring. housing for a lead feed mechanism lli.

The lead feed mechanism I4 is arranged as a unit assembly for disposition in the barrel I5 andincludes a helically slotted feed-tube l5, a longitudinally slotted guide tube I6, and a lead carrying and ejecting mechanism consisting of a lead grip sleeve Il and an ejector pin I8.

i As'mentioned abo-ve, the lead feed mechanism I4 is assembled as aunit, and for this purpose the guide tube It is fitted with a mounting sleeve I9 at its lower end, this mounting sleeve le being fragmentary.

7 Claims. (C1. 1Z0- 18) lil keyed with and retained on the guide tube I6 by aA dimple or boss formed in the guide Atube to fit a..slot in .the end of the mounting sleeve as illustrated at 2l) in Fig. 1. Also, thefeed tube I5, which is disposed in telescoped relation. for rotation on the guide-tube I B, is fitted with a lock sleeve 2`I similarly keyedand retained in position by a projection or bossV on the guide tube engaging a slot in the lock sleeve as indicated at 22 in F'ig. 1. The feed tube I5 and guide tube i5 are telescoped so that the lower end face of the lock sleeve 2| rests on. the top end face of the mounting sleeve I9, a ber washer23,being interposed to provide for smooth relative rotation` of these sleeves. f

The lead feed mechanism I4 is anchored in the lower portion I2 of the barrel. I by a press t of the mounting sleeve I9, in the writing; end of the lower portion l2 which is constricted as shown in the drawing. When pressed in place, a portion of the mounting sleeve I9 extends from the writing end of the lower barrel I2, and this extending portion of the mounting sleeve I9 is formed with external threads 24 to receive an internally threaded, metal, tip member 25. The writing end of this lower barrel portion I2 is shouldered as shown at 26 and the tip member 25 is formed Ywith a flange 2l adapted to seat externally on this shoulder 26r and thereby align the lower barrel portion` I2 with. the tip member 25.

v f Alignment of the parts is particularly important at this point, because any surfaceirregularity between associatedV parts at the writing end of the pencil not only impairsv its appearance but is an annoyance in use when the pencil is grasped at this portion for writing. The above described arrangement of the ange 2'7. on the tip member 25 for seating externally on the shoulder 26 at the writing end of the lower barrel portion l2 is especially Well adapted for obtaining effective alignment of the parts when a moulded plastic barrel is used in the pencil construction. Molded plastic parts have a tendency to give or spread under pressure in assembly, and the arrangement of the flange 2l on the tip member 25 not only forces alignment of the lower barrel portion I2 but contains it against the mounting sleeve i9 so that it cannot give or spreadT Operation of the lead feed mechanism I4 is provided for through an operating sleeve 2li-which isv fitted snugly, but freely for rotation, in the lower barrel portion I2, and is contracted at its lower end, as indicated at. 2S in Fig. l, to grip the lock sleeve 2l: fitted on '..thefeed .tube I5.

The operating sleeve 28 extends beyond the upper end of the lower barrel portion I2 so that the upper barrel portion II may be fitted over it as well, and ats 3l) are formed in a portion of this extending length to set up ribs 3l for frictional contact with the upper barrel portion II (compare Figs. 1 and 3). As the guide tube IB is fixed in the lower barrel portion I2 by the mounting sleeve I5, this frictional contact of the upper barrel portion II with the operating sleeve '28 allows the lead feed mechanism I4 to be actuated from the upper barrel portion II through the lock sleeve 2| keyed on the feed tube I5 and to which the operating sleeve 28 is fixed.

The operating sleeve 23 is further formed with a circumferential expanded portion 32 positioned in correspondence with the joint between the upper and lower barrel portions I I and I2 for aligning the barrel portions at this point. Also, the upper barrel portion II is advantageously fitted at this joint with an external ring member 33 to condition it, similarly to the writing end of the lower barrel portion I2, against giving or spreading as a result of repeated removal and replacement of the upper barrel portion I I on the operating sleeve 28 during use of the pencil.

Internally the operating sleeve 28 is fitted with spacing members 34 which are disposed as shown in Figs. l, 2, and 3 to support the feed tube I5 in alignment with the operating sleeve 28. These spacing members 34 also serve as partitions forming compartments adapted to receive reserve leads 35, and an eraser 35 may be disposed in the upper end of the operating sleeve 28 as a closure for the reserve lead compartments.

The lead carrying and ejecting mechanism incorporated in the lead feed mechanism I 4 according to the present invention is of the same general type illustrated and described in U. S. Patent No. 2,362,727, issued November 14, 1944, to B, D. Smith. A lead grip sleeve I7 is provided in the present case, as in the above noted prior patent, to grip and position a lead 31 for feeding by the lead feed mechanism I4. The grip sleeve I'I is formed with a recess or pocket defined by a lateral flange 38 (compare Fig. 5) proportioned to receive a lug 39 on the associated ejector pin I8, and to ride with the lug 39 in the longitudinal slot in the guide tube I6 so that the grip sleeve Il and ejector pin I8 are retained in proper spaced relation durl.

The longitudinal ing normal feeding movement. slot in the guide tube I6 is relieved near its lower end as shown at 4B in Fig. 4 to provide clearance for turning movement of the lateral fiange 38 so that the grip sleeve Il' may rotate upon substan tial exhaustion of the lead 37 to bring the lug 39 into alignment with a slot 4I in grip sleeve I'I and thus allow downward movement of the ejector pin I8 in the grip sleeve I'I to eject the exhausted lead as illustrated in Fig. 4. Reference is made to the above noted prior Patent No. 2,362,727 for further details of the arrangement and operation of the lead carrying and ejecting mechanism in this manner.

Feeding movement of the lead carrying and ejecting mechanism results from engagement of the helical slot in the feed tube I by the ejector pin I8, and the lead carrying and ejecting mechanism employed according to present invention differs over the one disclosed in the above prior Patent No. 2,362,727 principally in the improved arrangement by which the ejector pin I8 is adapted for engaging the feed tube I5. Ejector pins used in the lead feed mechanisms of mechani. cal pencils are commonly formed with a lug dis.-

posed to extend through a longitudinal slot in a guide tube and engage a helical slot in a feed tube so that relative rotation of the feed tube and guide tube causes feeding movement of the ejector pin. This same general arrangement is used according to the present invention, but with an improved arrangement of spaced lugs 42 on the ejector pin I8 for engaging the feed tube I5 so that end play in the lead feed is eliminated and a particularly smooth feeding movement is obtained.

The spaced lugs 42, as illustrated in detail in Figs. 5, 6 and 7 of the drawing, are disposed on the extending edge of a lateral projection 43 formed on the ejector pin I8 to extend through the longitudinal slot in the guide tube I6. These lugs 42 are formed with wing portions as shown extending transversely over the exterior surface of the guide tube I6 and oriented at an angle for engaging the helical slot in the feed tube I5, and the lugs 42 are spaced to ride opposed faces of successive turns of the helical slot. That is, the spacing of the lugs 42 is proportioned to ride the opposed faces (i. e., the opposite edge faces) presented by the body of the feed tube I5 between successive turns of the helical slot. As a result, the lugs 42 may be formed to ride more or less loosely in the helical slot for smooth and easy feeding movement and yet be associated with the feed tube I5 so that all objectionable end play is avoided.

A further feature of this arrangement of the ejector pin I8 is that between the spaced lugs 42 the lateral projection 43 is formed to extend slightly from the longitudinal slot in the guide tube I5 to ride the interior face of the feed tube I5 so that the lugs 42 are prevented from projecting beyond the exterior face of the feed tube I5 which would ,iam the lead feed mechanism. Also, as the lugs 42 are formed with wing portions extending transversely over the exterior surface of the guide tube I6, the disposition of the lateral projection 43 to ride the interior surface of the feed tube I 5 contains the ejector pin I8 against lateral shifting and thus additionally stabilizes the operation of the lead feed mechanism.

Smooth operating characteristics are also obtained by virtue of means employed according to the present invention for assembling the lead feed mechanism as a unit. This means, which is illustrated best in Fig. 8 of the drawing, comprises a relatively thin, flexible, metallic washer 44 fitted over the upper exnding end of the guide tube I5 and resting on the end face ofv the feed tube I5, a fiber washer 45 superimposed on the flexible washer 44, and a second, relatively rigid, metallic washer 46 superimposed on the fiber washer 45. Upon assembly of the lead feed: mechanism, ears 4'! are struck out in the guide tube I5 adjacent the longitudinal slot and a dimple or boss 48 is formed diametrically opposite` the longitudinal slot for retaining the superimposed washers 42, 45, and 46 pressed against the end face of the feed tube I5. Under this pressure the flexible washer 44 is flexed into the opening of the helical slot in the end face of the feed tube I5 which causes the flexible washer 44 to rotate with the feed tube I5 and thus insures metal on fiber friction between the flexible washer 45 and the fiber washer 45 during operation of the lead feed mechanism.

The present invention has been illustrated and described above in connection with a preferred embodiment in which the features of the invention are particularly well suited for use. However, it will .be recognized that these features are amava? alsoua'dapted for gener-'al use-otherwise'in mecha'nical pencil constructions, and such general application of the invention is'contemplated by the. appendedclaims.

' claim:

l. In a mechanical Apencil having va'lead feed mechanism includingahelically-slotted feed tube of uniform pitch throughout its length and a longitudinally slotted guidetube disposed for relative rotation inside said feed-tube, a lead'carrier adapted for longitudinal displacement in said guide tube and an associated ejector pin formed with spaced lugs, said lugs being formed to extend through the longitudinal slot in said guide tube for desposition in the helical slot in said feed tube and being spaced to ride the opposite edge faces presented by the body of said feed tube between successive turns of said helical slot, and said ejector pin having a lateral projection extending between said lugs and disposed in the longitudinal slot in said guide tube to ride the interior face of said feed tube and thereby prevent said lugs from projecting beyond the exterior face of said feed tube.

2. In a mechanical pencil having a lead feed mechanism including a helically slotted feed tube of uniform pitch throughout its length and a longitudinally slotted guide tube disposed for relative rotation inside said feed tube, a lead carrier adapted for longitudinal displacement in said guide tube and an associated ejector pin formed with a lateral projection disposed in the longitudinal slot in said guide tube and having spaced lugs formed on said projection, said lugs being formed for disposition in the helical slot in said feed tube and being spaced to ride the opposite edge faces presented by the body of said feed tube between successive turns of said helical slot, and said lateral projection being formed to ride the interior face of said feed tube and thereby prevent said lugs from projecting beyond the exterior face of said feed tube.

3. In a mechanical pencil having a lead feed mechanism including a helically slotted feed tube of uniform pitch throughout its length and a longitudinally slotted guide tube disposed for relative rotation inside said feed tube, a lead carrier adapted for longitudinal displacement in said guide tube and an associated ejector pin formed with a lateral projection disposed in the longitudinal slot in said guide tube and extending slightly from said slot to ride the interior face of said feed tube, and spaced lugs formed on the extending edge of said lateral projection, said lugs being formed with wing portions extending transversely over the exterior surface of said guide tube and oriented at an angle for disposition in the helical slot in said feed tube, and said lugs being spaced to ride the opposite edge faces presented by the body of said feed tube between successive turns of said helical slot.

4. A mechanical pencil comprising a barrel having a lower portion and an upper portion, a lead feed mechanism including a helically slotted feed tube and a longitudinally slotted guide tube, 1

said guide tube being xed at one end in the lower portion of said barrel, and said feed tube being assembled in telescoped relation for rotation on said guide tube, means adapting said feed tube for rotation by the upper portion of said barrel, and means disposed at the extending end of said guide tube for retaining said feed tube in assembled relation comprising a relatively thin, flexible, metallic washer tted over said guide tube and resting on the end face of said feed tube, a ber washer superimposed on saidnexible washer, and a relatively rigidmetallic washer superimposed on said fiber washer, said guidetube having. positioning` means at its extending" end for retaining said washers pressed against the end face of said feed tube, whereby said .flexible washer is flexed into the opening of the helical slot in the endgfa-ce of said feedftube thereby causing saidflexible washer Atorotate with said feed tube and insuring -metal 'on ber friction between said flexible-washer and said fiber washer during operation of said lead feed mechanism.

5. A mechanical pencil comprising a hollow plastic barrel having separate upper and lower portions, a lead feed mechanism including a helically slotted feed tube and a longitudinally slotted guide tube, said guide tube being fixed in the lower portion of said barrel, and said feed tube being assembled in telescoped relation for rotation on said guide tube, and an operating sleeve associated with said feed tube and extending from the lower portion of said barrel for frictional contact with the upper portion of said barrel, said operating sleeve having an expanded portion positioned at the joint between the upper and lower portions of said barrel for aligning said barrel portions at this point.

6. A mechanical pencil comprising a hollow plastic barrel having separate upper and lower portions, a lead feed mechanism including a helically slotted feed tube and a longitudinally slotted guide tube spaced concentrically in said barrel, said guide tube being fixed in the lower portion of said barrel, and said feed tube being assembled in telescoped relation for rotation on said guide tube, an operating sleeve tted snugly in the lower portion of said barrel, but free for rotation in said lower portion, and extending for frictional contact with the upper portion of said barrel, said operating sleeve being contracted at the end fitted in the lower portion of said barrel to grip said feed tube, and spacing members disposed in said operating sleeve for aligning said feed tube.

7. A mechanical pencil comprising a hollow plastic barrel having separate upper and lower portions, a lead feed mechanism including a helically slotted feed tube and a longitudinally slotted guide tube assembled in telescoped relation, a mounting sleeve fixed on said guide tube and in the lower portion of said barrel for securing said guide tube relative to said barrel portion, an operating sleeve fixed to said feed tube and extending from the lower portion of said barrel for frictional contact with the upper portion of said barrel, said operating sleeve having an expanded portion positioned at the joint between the upper and lower portions of said barrel for aligning said barrel portions at this point, and said mounting sleeve having an externally threaded portion extending from the writing end of said lower barrel portion, and a metal tip member internally threaded for assembly on the extending threaded portion of said mounting sleeve, the writing end of said barrel being shouldered, and said tip member being formed with a flange adapted to seat externally on said shoulder and thereby align the barrel with said tip member.

HERBERT W. SAMS.

(References on following page) REFERENCES CITED Number The following references areof record in the 110551 file of this patent: `UNITED STATES PATENTS v5 211813522 Number Name Date 2,489,714

1,900,669 Sheaffer et a1 Mar. '7, 1933 2,009,182 Kahn July 23, 1935 2,028,380 Deli Jan. 21, 1936 Number 2,030,025 Davis Feb. 4, 1936 1o 412,376

Back Oct. 5, 1937 Name Date Friedlein Mar. 8, 1938 Stenerson May 16, 1939 Schaefer June 27, 1939 Keeran Nov. 28, 1939 Lynn Nov. 29, 1949 FOREIGN PATENTS Country Date Great'l Britain June 28, 1934

Images