US2207810A - Pencil - Google Patents

Description

C. T. LINK July 16, 1940.

PENCIL Filed March 2o, 193'/ 2 sheets-sheet 1 INVENToR u C/zcz/Ze ZZUZ ATTORNEY EM M w@ WNW R1 imm w QM uw@ b NN w Il mvnl; .......HHH.HHMhnsumwwmvh ,..w,...,, mw *Nw C. T. LINK 'July 16, 1940.

PENCIL 2 Sheets-Sheet 2 Filed March '20, 19:57

. Y W5 mn mk m. Y ZB U @w NN Nh MQN giii NSN Patented July 16, 1940 UNITED STATES rl'irlazNTr loFFlcla.

22,207,810 PENol'L f charles r1. Link, chicago, In. Application March 20, 1.93'1,v Serial No. 132,127 y 14 claims. (01.120-18) of the invention is to provide in a mechanical pencil projecting lmeans which, upon reaching the extreme forward position of its f travel, automatically returns to its extreme rear position. f

A further object of the invention is to' provide a lead maga-zine whichv can be inserted in loaded condition in the pencil and' which includes means for positively moving the leads automatically and successively to ejecting position.

Further objects, advantages andv capabilities of the invention will be apparent' rfrom the following descriptionof preferred embodiments vof the invention taken in conjunction with the accompanying drawings, in which y Fig. 1 is a longitudinal cross'section of a pencil embodying the invention;

Fig..2 is an exterior View of the barrel;

Fig. 3 is a perspective View of the clip;

Figs'. 4 and 5 are perspective views of alternative types of thread followers;` y

Fig. 6 is an end view and side elevation of thel lead ejector; l j l Fig. 7 is a side elevation of the spring which returns the lead ejector to the rearwardr extremity kof its travel;

Fig. 'la is an end view thereof;

of the lthread Figs.v 8 and 9 are slde elevations members; Figs. 8a and 9a are correspondingv end views thereof;

Figs. 10 and 11 are perspective views ofthe tip member;

Fig. l2 is a side elevation, partly in section, of the driving tube;

Fig. 13 is a longitudinal cross section of a further embodiment of the invention;

members of the pencil shown in Fig. 13;

Figs. 14a and 15al are corresponding lendA views thereof; l Fig. 16 is a side elevation', partly in'sectiomof pencil.

Figs. 14 and 15 arevside elevations of the thread the driving tubeof 'the pencil shown in Fig. 13;'

Fig. 18 is a perspective View,A partly I broken away, of j a magazine for theleads;

Fig. 18a is a perspective View of a closure member therefor;

Figs. 19 andl20 are'perspective views of valterv native types: of springs for the magazine;

Figs; 21, 22 and 23 are end views of the magazine with different numbers of leads therein;

Fig.; 24 a perspective View, partly broken away, ofY another magazine for the leads;

Fig. 25 is a fragmentaryl side elevation of a spring for the magazine shown in Fig. 2,4;

Fig. 25ais an end elevation thereof; and Figs. 26, 27 and 28 are end views of the magazine shown in Fig. 24 with different numbers of leads therein.v f

In the pencil shown in Fig. l there are three principal elements, namely, the 4tip member I, the magazine M and the lead ejecting means.

The tip member I frictionally grips the lead therein-and preventsit from sliding out of the As shown in Fig. 10, the wall at the lower end of the tip member is relatively thin and formed in the shape of a triangle. The triangle is of such size that whena lead is pushed through the tip member, the sides of the triangle are bowed outwardly as'shown rin Fig. 11; This resuits in a pressure being exerted 'by the sides of the triangle upon the lead and causes the lead to be frictionally gripped by the tip member.

TheA upper portion 2 of the tip member is ycylindrical and is frictionallyheld in a corresponding recessin closure member 3. The latter tapers ysmoothly from the tip memberto the cylindrical barrel 4 and has a cylindrical upper portion 5 which is frictionally and removably held in the lowerend portion of cylindrical drivbarrel 4'. Grooves'l' (see Fig. l2) are provided in tube 6 to prevent relative rotation between the 'tube and closure member 3.

tdfsay that the magazine is soy constructed that,

when ejector rod I5 has pushed centrally posiltioned leadr L1' out ofthe magazine through the lower end thereof andhas thenwithdrawn from v' the magazine through the` upper end thereof,

the next succeeding le'aduLz willvb'e moved automatically yinto the central or ejecting position lpreviously occuped by leadv 1u.

Now as to the ejecting means, the driving tube fing vtuber Bwhich is. rotatably mounted in the bers.

6 thereof is mounted to rotate relative to barrel 4 but is restrained against longitudinal movement relative to the barrel by thread members 8 and 9 (see Figs. 8 and 9) which are cemented or frictionally held in the upper portion of the barrel. Thread members 8 and 9 together .encircle the upper cylindrical portion I0 of driving tube 6 and have inwardly extending bead portions II which enter into neck I2 in the driving tube to prevent longitudinal movement thereof. Within the upper portion I0 of the driving tube is a coil'spring |3.` At the lower end of spring' I 3 is a closely wound graduated end portion IILy The upper and"JVJ the ejector rod reaches the lower end ofthe which bears against neck I2.

large end of portion I4 just fits into portionnIIl` of the driving tube while the lower and small end has a sliding fit around ejecting rod I5 which it holds concentrically of the driving tube. The

remainder of spring I3 has a diameter some-i' what smaller than the large end of portion I 4-so that the -spring may be fully compressed within portion I0 .ofthe driving tube. Ejector rod I5 termina-tes atthe upper end thereof in a head i6 which has a sliding fit within portion IU of the driving tube and bears against the upper end of"A spring I4. Diametrically through head I6 is a hole I'I within which is rotatably mounted a T-shapedthread follower I8. Ihe thread follower may have a square shank as shown in Fig. 4 or a round shank as shown in Fig. 5. The head I9 of the thread follower is flat on the sides and on the top is'curved as shown in Figs. 4 and 5. The head I9 and a small portion of the shank of the thread follower extend through a longitudinal slot 2|! in portion II! ofthe driving tube into an internal thread 2| in thread members 8 and 9. Rotating of the driving tube clockwise relative to the thread members (viewing the pencil from the tip end) results in edge 22 of slot 20 engaging the shank of thread follower I8 and moving the thread follower along internal thread 2| toward the tip of the pencil. As the thread followeradvances it slides along edge 22 and carries with it head IB and ejector rod-|5, resulting in compression of spring I3. When the thread followerr has reached the lower end 23 of thread 2! (seeFig. 9), the force of compressed spring I3 against head I6 causes the thread follower to pivot to a position in which head. I9 is substantially parallel to the axis of the pencil and then to slide upwardly along groove 24 until head I8 reaches the end portions 25 of the thread mem- Further clockwise rotation of the driving 'tube then causes the thread follower to pivot in the recess 26 of thread `member 9 and re-enter thread 2| and advance again toward the tip of the pencil. In order to permit pivoting of the thread member at the lower end (23) of the thread, a recess 21 is provided in thread member 9.

In order to insure that head I9 will slide smoothly across groove 24 when travelling along thread 2|, and slide smoothly across thread 2| when travelling along groove 24, the head I9 is made just wide enough to have an easy sliding fit in thread 2| and groove 24 and somewhat greater than twice as long as it is wide. In practice a length approximatelyfour times the width has been foundvery satisfactory. This permits the head to bridge the gaps in thread 2| before the center of the head has reached the gaps.

gaps and prevents the head fromr pivoting into v thread 2|.

In operation, as the driving tube 6 is rotated clockwise relative to the thread members by rotating closure member 3 clockwise relative to the barrel, and thread follower I8 and ejector rod I5 advance toward the tip of the pencil, the ejector rod I5 pushes the centrally positioned lead L1 out of the magazine toward the tipmember and lead L1, in turn, until it reaches the tip member, pushes the preceding lead Lo through the tip member. When lead L1 reaches the tip member it is pushed therethrough by the ejector rod until the upper end of lead L1 and the lower end of k their travel. This places the lower end of the ejector rod at the upper end of the magazine and permits the lead positioning means in the magazine to move the next lead L2 into alignment with lead L1. Further clockwise rotation of the closure member then causes the ejector rod to move downwardly, pushing leads L2 and L1 lahead of it in the manner explained above in connection with leads L1 and Lo. When lead L2 has been pushed completelyout' of the magafrom, lead L3 is positioned for ejection; and so 4zine and the ejector rod has withdrawn thereon until no more leads are left in the magazine. j

When the magazine has been lemptied it may be replaced by a full magazine by removing closure member 3, tipping the pencil to cause the emptied magazine to slide out, inserting the full magazine in the pencil and replacing closure member 3. When doing this, however, it is desirable that the ejector rod be inits retracted position so that it will not push the centrally positioned lead out of the magazine as the latterl` is inserted in thepencil.

It will be noted from the foregoing that successive .leads may be fed to the tip of the pencil by rotatingclosure member 3 relative to the bar- `rel in the clockwise direction. In other words, it is unnecessary to rotate the closure member in the counter-clockwise directionto permit new leadsto be positioned for ejection inasmuch as retraction of the. ejector rod is effected automatically by .spring I3 when the thread follower has reached the lower end 23 of thread 2|.

If a lead is pushed out of the tip .member farther than desired, rotation of the closure member in the counter-clockwise direction will cause retraction of the ejector rod |5..and permit the lead to be pushed back into the pencil.

As will be noted from Figs. l and 12, the slot 20 in 'the driving tube is tapered, edge 28 being and edge 22 being inclined therefrom. The purpose of this taper is to prevent edge 22 from be-V ing pressed against thread follower I8 as the latter moves upwardly along groove 24, notwithstanding that the driving tube is being rotated lower end 23 of thread 2| and was starting to move upwardly along groove 24 under the influence of spring I3. The usual situation would be for the operator Vto continue rotating the substantially parallel with the axis of the pencil 60 closure member after the-'thread follower had 75 lIi() reached this point. lNow if edge 22 were parallel with the axis of the pencil, such continued rotation of the closure member after the thread rfollower had'started its upward movement along groove 24 would result in edge 22 engaging the thread follower and pressing it against the -wall of the groove, and this might stop the movement of the thread follower along the groove. However, by inclining edge 22 away from the path of the thread follower, the closure member can be rrotated to a certainy extent while the thread fol- Ilatter tapers inwardly toward a circular enlargement 3| at its end. Referring to Figs. 1 and 2, the barrel is provided near its upper end with an outwardly pressed formation 32 conforming to the shape of anchor arm 3|, and an opening S3-at the upper end of portion 32. When assembling the pencil, anchor arm 30 is inserted through opening 33 into the barrel 4 and moved to a position in which it is located in the formation 32. The thread members 8 and 9 permanently mounted on the `driving tube 6 are inserted together with the driving tube into the barrel 4. The thread members 8 and 9 are cemented or otherwise rigidly mounted in the barrel 4 and they cooperate with the formation 32 against any tendency to move the clip.

An eraser l34 is fitted into the top end of the barrel above thread members 8 and 9. A cap, not shown, fitting over the top portion of the barrel may be provided if desired to enclose the eraser.

The pencil shown in Fig. 13 differs from that shown in Fig. 1 principally in that it is operated from the upper end whereas the pencil shown in Fig. 1 is operated from the tip end.

The tip member I 0| is similar to the tip member I. The closure member |03 is similar to closure member 3 except that portion |05 fits directly vinto the barrel |04. The vspring H3, ejector rod II5, head II6 and thread follower 1| I8 are similar to the corresponding elements of Fig. 1 and are arranged and function in same manner. The magazine M1 functions in the same way as magazine M and may be removed through the lower end of the barrel |04 upon the removal .of the closure member |03. The principal constructional differences are in the thread members |08 and |09 and the driving tube IIO. The thread I2I isin the opposite direction to that of thread 2|, the thread 2| being a right hand internal thread whereas thread 2| is a left hand internal thread, and recesses |26 and |21 and groove |24 are arranged to function in the same ymanner as the corresponding elements in thread member 9. Inwardly extending bead portions ||I function the same as portions II, extending into neck I|2 in the driving tube IIO, but thread members I 08 and |09 are both open at the top end. 1inv assembly, thread members |08 and I 09 are secured together and are cemented or otherwise rigidly secured to the barrel |04.

The driving tube I0 terminates at the lower end of neck |I2. At its upper end the tube I|0 has an enlarged portion 35 beyond and in alignmentv with the barrel |04. The outer diameter ofthe portion 135 is slightly greater than the Referring to Fig. 3, theA outer diameter of the barrel. A cap 36 fits snugly over portion 35 and covers an eraser 31 contained therein. When the cap 36 is manually rotated relative to the barrel, the tube |I0 is rotated relatively to the barrel |04 and the thread members |08 and |09. The slot |20 corresponds to slot 20. However, the edge |22 is parallel to the axis of the pencil and edge |28 is inclined from the axis of the pencil. This change is necessary because in ejecting the leads tube IIO is rotated counter-clockwise relative to the thread members viewing the pencil fromthe tip end. A disk 38 having a central embossed central portion 39 is fixed in enlarged portion 35 to serve as an abutment for head II6 when the latter is returned to its upper position by spring II3.

In the operation of the pencil shown in Fig. 13, counter-clockwise rotation of cap 36 relative to the barrel, Viewing the pencil from the tip end, results in driving tube I I0 rotating counterclockwise relative to thread members 08 and I 00, and causes edge |28 to engage the thread follower II8 and advance it along thread |2| toward the tip of the pencil. As the thread follower ||8 advances it carries with it head ||6 and ejector rod II5 and causes spring |I3 to be compressed. When the thread follower I I8 reaches the lower end |23 of the thread I2| it pivots inthe recess |21 and returns upwardly along groove |24 under the influence of spring |I3 until head |I6 abuts against central embossed portion 39 of disk 38. Further rotation of the driving tube in the same direction, causes. the thread follower to pivot in recess |26 and re-enter thread I2I. As ejector rod |I5 moves downward, it pushes the lead or leads ahead of it toward and through the tip member IOI. When the ejector rod reaches the lower end of the magazine and is returned upwardly out of the magazine under the influence of the spring ||3 the next succeeding lead in the magazine is moved to central or ejecting position and is engaged and ejected by the ejector rod II5 upon -subsequent downward movement thereof. As in the pencil shown in Fig. 1, rotation of the driving tube in the direction opposite from that required for ejection results in retraction of the ejector rod and permits a lead protruding from the tip member to be pushed back into the pencil. The inclination of edge |28 is for the same purpose as the inclination of edge 22, namely, to enable the automatic retraction of the ejector rod notwithstanding rotation of the driving tube during the retraction. i

In this pencil, as in the pencil shown in Fig. l, successive leads may be brought to ejecting position and ejected from the pencil without the driving tube having at any time to be rotated in the direction opposite from that required for ejection.

Referring to Fig. 18, the body of the magazine M comprises a solid body, suitably of moulded material. It is provided with a slot 40 which extends the whole length of the magazine and is of spiral form in cross section. 'Ihe slot 40 is slightly wider than the diameter of the leads so .that the leads, which are arranged in succession in the slot with their axes parallel to the axis of the housing, may easily be moved from one end of the spiral slot 40 to the other. The inner end of the spiral slot is at a position to hold a lead substantially coaxial with the housing and in alignment with the ejector rod I5. From this position, see Fig. 21, the slot curves smoothly into an arcuate portion which constitutes the major portion of the slot and extends around the periphery of the magazine body. At one end of the magazine housing is an `end wall 4I which closes that end of the slot save for a central opening for a lead to pass therethrough. The other end of the slot is closed, save for a similar central opening, by a centrally perforated disk 42 which fits into the end of the housing.

Referring again to Fig. 21, the leads L are arranged side by side in slot 40 beginning at the inner end thereof and ending a short distance from the outer end thereof. Between the outer end of the slot and the last lead is a compressed spring S. In its extended condition, the spring S may be of the form shown in Fig. 19 or the form shown in Fig. 20. The spring or Fig. 19 consists of a number of fiat coils whose lengths inc-rease gradually from one end of the spring to the other. The shape of the spring as a whole is flat and tapered. The spring of Fig. 2O is similar to that of Fig. 19 except that it has fewer coils and the spring as a whole is curved instead of flat. The compressed spring is arranged in-the magazine with the small end of the spring against the outer end of slot 4E! and the large end of the spring against the last lead. The leads are thus positively urged toward the inner or central end of the slot and when the central lead is ejected from the magazine the spring pushes all the remaining leads toward ycentral position a distance equal to the diameter of a lead and locates in the central position the lead which previously was next to the lead ejected from the magazine. When this newly located central lead is ejected from the magazine the process is repeated, and so on, until, as shown in Fig. 22, the magazine is only about half full or until, as shown in Fig. 23, only one lead remains in the magazine.

The curvature in the spring of Fig. 20 facilitates the expansion of the spring around curved slot 40. If the spring is flat as in Fig. 19, it is necessary to have more coils in order to insure expansion of the spring completely around the curved slot 4t. The end of the wire at the large end of spring S is bent, as indicated by reference numeral 43 in Figs. 19 and 20, in order to insure that the end of the wire will bear against the last lead and not become wedged between the. leads and the wall of the slot. Bend 43 extends beyond the adjacent coil so as to avoid becoming tangled therewith when the spring is compressed.

When the magazine is in either one of the pencils described above, the lead at the inner or central end of slot 40 is substantially coaxial with respect to the pencil and is ejected from the magazine by the ejector rod I5 or II5, and when the ejector rod has' then been retracted from the magazine by the return spring I3 or II3 spring S moves the next succeeding lead to central or ejecting position.

The magazine illustrated in Fig. 24 is similar to that of Fig. 18 except that the slot 44 for the leads is provided at itsfouter end with a longitudinal enlargement 45 and adjacent the ends of the housing with spiral enlargements 46 and 41. The purpose of these enlargements is to provide a track for a coil spring 48 which, when the magazine is full of leads, is compressed in portion 45 and which, when the central lead is ejected from the magazine, expands along portions 46 and 41 and bears against the extremities of the last lead to push the leads toward central position. The spring 48 is somewhat greater in diameter than the width of slot 44 between the enlargements 46 and 4l so that it will be prevented from expand-j ingl out of portions45,` 46 or 41 into the remainder of the slot.L Fig. 26 showsthe magazine with a full supply of leads L with spring-48 bearing against the last lead. Fig. 27 shows the condition of the magazine afterabouthalf the leads have been ejected with spring 48 urging thel lremainder toward central position. Fig. 28 shows the magazine after the last lead has been pushed into central position by spring 48. Centrally perforated disks similar to disk 42 are leads and spring therein. The magazine shown in Fig. 24 operates in the pencil shown in Fig.`1 or Fig. 13 in the same manner as the magazine of Fig. 18, that is, when `the ejector rod I5 o-r I I5 has ejected the centrally positioned lead from the magazine and has automatically retracted, the

spring 48 pushes the next succeeding lead into.

central position.

It is immaterial which end of either magazine n is insertedin the pencil iirst as the springs S or 48 function equally well in both relations. When vthe last lead has been ejected from` the magazine it is intended that the emptymagazine be withdrawn and discarded and a full new magazine inserted in the pencil. In order to notify the user when the magazine is almost empty, it is profposed that the last lead or two shall have a distinguishing appearance such as being coated or tipped with a material of different color.

As shown in Fig. 8 I prefer to provide near the upper end o-f thread 2| a recess terminating in a shoulder 49 so arranged that if it is attempted ,y

completely to the upper end thereof, the

possible to advance the upper end of lead Li (for example) to a point slightly above the lower end of lead L2 and then manually retract the Y ejector rod completely out of themagazine, permitting the leads other than lead L1 in the magazine to be tilted (by spring S or 49) tol a position in which the upper end of lead Le is'in central position and the lower end of lead Ie is held out of central position by the upper end of lead L1'. Subsequent downward movement of the ejector rod would then jam lead L2 against the lower end of the magazine and necessitate removal of the magazine from the pencil to permit withdrawal of lead L1 from its obstructing position in the magazine. Shoulder 49, however, by preventingv manual retraction of the ejector rod completely out of the magazine, obviates this possibility of jamming the pencil. Shoulder |49 in` thread I2I (Fig. 15) is for the same purpose as shoulder 49.

Although the invention has been described in connection with the specific details of preferred embodiments thereof, it must be understood that such details are not intended to be limitative of the invention except insofar as included in the accompanying claims. v

Having thus described my invention, I declare that what I intend to claim is:

1. An automatic pencil comprising a barrel, a tip member at one end of the barrel having an axial opening for the discharge of lead, a threaded member in the barrel, a lead magazine in said barrel below said threaded member and having axial openings,and a longitudinal groove terminating adjacentr the axis of the magazinev so as to locate a lead in co-axial relation tov said magazine and openings, a thread follower adapted to cooperate with said threaded member, a rod located in alignment with theaxis of the magazine and operatively connected to said thread follower so asr to move axially therewith, means for manually rotating said follower relatively to the threaded member to effect longitudinal movement of the follower and lead ejecting rod, a spring tending to retract the thread follower and rod, said threaded member being provided with a longitudinal groove adapted to receive the follower at the end of an expelling movement to permit the spring to retract the rod and follower.

2. An automatic pencil comprising-a barrel, a tip member at one end of the barrel `having an axial opening for the discharge of lead, a threaded member in the barrel, a leadmagazine in said barrel and provided with means for feeding leads into alignment with said axial opening, a thread follower adapted to cooperate with said threaded member, a rod located in alignment with the axis of the magazine and operatively connected to said thread follower so as to move axially therewith for ejecting axially aligned leads through said axial opening, a sleeve'having a longitudinal slot to effect manual rotation of the follower relative to the threaded member to cause longitudinal movement ofthe follower and lead v v l generally spiral shape adapted to contain a series ej ecting rod, a spring tending to retract the thread follower, said threaded member being provided with a longitudinal groovecommunicating with the thread of said threaded member for receiving the follower at the end of an expelling-movement to permit the spring to retract the rod and follower.

3. An automatic pencil comprising a barrel, a tip member rotatably mounted at one end of the barrel having an axial opening for the discharge of lead, an. internally threaded member vin the barrel, a lead magazine in said barrel between said tip and said threaded member and adapted to feed leads into alignment with said axial opening,l a thread follower adapted tocooperate with said threaded member, a rod located in alignment with the axis of the magazine and operatively connected to said thread follower so as to move axially therewith for moving leads through said axial opening, a sleeve rigid with the tip member having a longitudinal slot to effect manual rotation of the follower relative to the threaded member to cause longitudinal movement ofthe follower and lead ejecting rod, a spring tending to retract the thread follower, said threaded member being provided with `a longitudinal groove provided with terminal extensions communicating with the ends of said thread for directing the follower into said groove at the end of an expelling movement to permit the spring to retract the rod and follower and for redirecting said follower from the groove into said thread upon retraction of the rod and follower by said spring.

4. An automatic pencil comprising a barrel, a tip member at one end of the barrel having an axial opening for the discharge of lead, a threaded member in the barrel, a lead magazine adapted to feed leads into alignment with said axial opening, a thread follower adapted to cooperatewith said threaded member, a rod operatively connected to said thread followersoas to move axially therewith for moving leads through said axial opening, a sleeve having a longitudinal slot to effect manual rotation of the follower relative to the threaded member to cause longitudinal movement "of the follower and lead ejecting rod, a member carried by said sleeve beyond the upper Aend of the barrel wherebyv the sleeve may be rotated manually, a spring. tending to retract the f thread follower, said threaded member being provided with a longitudinal groove provided with a terminal extension co-acting with the threads of said threaded member for directing the follower into said groove at the end of an expelling move- -ment to permit the spring to retract the rod and move the leads through the slot successively vto l said ejecting position. I v

6. A magazine for a mechanical lead pencil adapted to be inserted into vand removed fromY the pencil and consisting of a housing having a longitudinal slot of generally spiral cross-section adapted to contain a series of leads, and resilient means adapted positively to movefthe leads through the slot towards one end ofthe slot.

7. A magazine for a mechanical lead pencil adapted to be insertedv into and removed from the pencil comprising a housing having a slot of of leads, a coil spring compressed between the outer end of the slot and the last lead in the series and consisting of a number of flat coils for moving the leads through the slot to lead ejecting position.

f 8. A magazine for a mechanical lead pencil adapted to be inserted into and removed from the pencil and comprising a housing having a slot' of generally spiral shape adapted to contain a series of leads, and a coil spring compressed between the outer end of the slot and-thelast lead in the series to move the leads to lead ejecting position, said spring consisting of a number of iiat coils whose lengths increase progressively from one end of the spring to the other, the large end of the spring bearing against the last lead and the small end of the spring bearing lagainst the outer end of the slot.

9. A magazine for a mechanical lead pencil adapted to be inserted into and removed from the pencil and comprising a housing having a longitudinal slot of generally spiral cross-section.

adapted to containa series of leads, and a spring expansible Within the slot to move the leads through the slot to ejecting position therein, said spring being a coil spring compressed between the outer end of the slot and the last lead in the series and consisting of a number of flat coils whose lengths increase progressively from one end of the spring to the other, the large end of the spring bearing against the last lead and the small end of the spring bearing against the outer end'of the slot, and the spring as a whole, particularly near the large end thereof, being curved to assist it in expanding around the-spiral slot.

10. A magazine for a mechanical lead pencil adapted to be inserted into and removed from position therein, said spring being a coil spring 75 compressed between the outer end of the slot and the last lead in the series, said coil spring being greater in diameter than the width of the slot and adapted to expand along said enlarged portion at thel outer end of the slot and along said enlarged portions at each end of the magazine.

11. A magazine for a mechanical lead pencil adapted to be inserted into and removed from the pencil and comprising a housing provided with a slot of generally spiral shape extending longitudinally therethrough and adapted to contain a series of leads, and resilient means adapted positively to move the leads through the slot to ejecting position therein, the inner end of the slot being located to hold a lead substantially coaxial with respect to the exterior of the housing.

12. In combination a mechanical lead pencil, a

vmagazine adapted to be inserted into and to be removed from the pencil and'consisting of a housing having a slot, leads in `said magazine, and means adapted positively to move the leads through the slot to ejecting position therein, at least one of the latter leads in the succession being distinctly colored to indicate the amount of lead remaining in the magazine.

13. A pencil comprising a barrel provided with a tip, said barrel having an internal thread, a lead feeding plunger within the barrel, a spring in the barrel compressible by the plunger as the latter is operated to'feed a lead through said tip, a follower pivotally connected to said plunger and coo-perable with the threads of said barrel for advancing the plunger within'the latter, and a longitudinal groove within said barrel traversing Vthe convolutions of said thread and provided with terminal portions communicating with the ends of said thread, the lower of said portions beingarranged to swing said follower pivotally at the end of the lead feeding operation for directing said follower from the thread into said groove for retraction of the follower and plunger by said spring, said other terminal portion of the groove being adapted to directthe follower from the groove into positionk for co-action with said thread upon retraction of the plunger by said ing the sleeve tothe threaded member for restraining relative axial movement of the sleeve within the barrel, a lead advancing rod in said sleeve aligned with the passage of said magazine and provided with a thread follower projecting through the slot of said sleeve for cooperation a1- ternately with said thread and groove whereby upon rotation of the sleeve the follower is moved by the thread longitudinally of the barrel to cause the rod to advance a lead downwardly through said magazine passage, a spring in said sleeve having one end in contact with said follower and the otherend comprising a plurality of convolutions of successively reduced diameters constituting an abutment adapted to seat on said spring seat of the sleeve and providing a centralized guiding passage for said rod, said spring being oompressible by said follower during the lead advancing movement thereof whereby upon the movement of said follower from the thread into said groove said follower is restored by said spring to the upper end of the thread and said rod is retracted from the magazine to enable another lead to be fed from the magazine into said magazine passage.

CHARLES T. LINK.

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