US2181622A

US2181622A - Breech loading pencil

Info

Publication number: US2181622A
Application number: US145992A
Authority: US
Inventors: Franklin H Keeran; Charles R Keeran
Original assignee: Individual
Current assignee: Individual
Priority date: 1937-05-27
Filing date: 1937-05-27
Publication date: 1939-11-28
Anticipated expiration: 1956-11-28

Description

Nov. 28, 1939. F. H. KEERA-N ET AL BREECH LOADING PENCIL Filed May 27, 1937 3 Sheets-Sheet l l bh 0.9/ NN/ NNI. S

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Nov. 28, y'1939.

F. H. KEEAN ET Al.

BREECH LOADING PENCIL Filed May 27. 1957 3 Sheets-Sheet 2 u v I /f Ofjze 5 f2/*@7255 f Zes Nov. 28, 1939.

F. H. KEERAN m AL BREECH LOADING PENCIL ssheets-sheet s v Filed May 2'7, 1937 @jazz t '45' Figure 9 is a transverse section taken Patented' Nov. 28, 1939 UNE-TED STAT-Es l Bannon LOADING PENCIL i Franklin I-LKeeran and Charles R. Keeran,

Evanston, Ill.

Application May 27, 1931, serial No. 145,999

1,4 Claims.

This invention relates to mechanical pencils of the type in which the rotation of one part of the pencil body relative to another part about their common axis operates to drive a plunger axially 'f5 within the pencil body for propeuing the lead therein and projecting a portion of it from 'the pencil tip. One object of this invention is to provide a mechanical pencil adaptedto utilize an unusually long section of lead Without reloading. Another object is to provide a pencil in which the lead may be inserted through -the upper end of the pencil, that is, the end remote from the writing tip. Another object is to pror vide a mechanical pencil which shall be simple and economical to manufacture. Other objects will appear as the description proceeds.4 The invention consists of certain features 'and elements of construction in combination, as herein Vshown and described and as indicated by the claims.

In the drawings: u Figure l 'is an axial sectional View of a pencil embodying this invention, the middle portion of the'pencil body being broken out to condense the View. y

'2'5 Figure 2 is an axial sectional'view of the tip and the adjacent part of the barrel on ak larger scale than Figure 1, and showing further details of the structure.

Figure 3 is an enlarged section on thesame scale as Figure I2,'showing the upper end portion of the pencil with on the barrel. Y

Figure 4 is a-transversesection taken as indicated at lineV 4 4 on Figure 2. v

3'5- Figure 5 is a transverse section taken as indicated at line 5-5 on Figure 3. Figure 6 is an enlarged View of the taken in a plane at right angles to the ,views 0 u 7 this part in Figures 1 and 3. u it' Figure 7 isa detail section taken axially of the pencil showing some of the same parts as-Figure 2. f

FigureS is an enlarged detail section similar to Figure 3, showing modied construction.

the cap and eraser in place .as indicated at line 9 9 on Figure 8. l

Figure l0 is a transverse section taken similarly v toFigure 4 but showing a modified construction A and omitting the. supply of spare leads.l 'd Figure 1l is a detail section taken as indicated at linev H-H on Figure 10.

Figure 12 isa transverse section taken similarlyy to Figure 4 but illustrating another modification 55; of theI structure..

Figure 13 is an axial sectional View similar to Figure l but showing a bullet type of pencil equipped with the mechanism embodying thisV invention. 691 Figure 14 isa side elevation of the pencil shown plungery (Cl. 1Z0-18) y *in Figure 1`3 but with the tip extendedin .position for use. i u Figure 15 is a transversesection taken as indicated at line I5-l5 on Figure 13. I Figure 16 is an enlarged sectionaly view of the '5 tip end of a pencil of modified construction, in which the tip does not rotate with respect to the barrel.`

Figure 17 is an enlarged sectional view-k of the upper end of the pencil showing the arrangement '150 for rotating thehead portion for feeding the lead.

Figure 18 is a transverse section taken as indicated at' line l8--I8 on Figure 16.v

Most mechanical ,pencilsA are made approximately six inches in length in order to be convenient to handle in writing,'but in most of them only asmall portion of this length isutilized for the section of lead in use. This requires frequent renewal of the lead, with Waste of' time and ef- '20 .'fort. Our invention permits the greater portion v of the ,pencil barrel to be filled with the section of lead'in actual use, with the result that this leadrmay be substantially four vinches in length, and rwill require renewal much less frequently i than theone and three-eightsinch leads in vcommon use. `The barrel may also be designedas a magazine to accommodate a large numberof 'spare leads of the four-inch length.

A further improvement embodied in the present structure is the arrangement of the parts to permit removal .of the lead-propelling plunger from the upper end ofthe pencil barrel so that thev new lead may be inserted from this end instead of beingintroduced through the tip. This 15 muzzle` or tip-loadingis a delicate task, often resulting in broken leads. u

4Referring iirst to Figure 1, it will be seen that the bodyv of the pencil includes a barrel comprising a shell l which is shown as of substantial thickness, and which may be composed of Bakelite, Pyrolin or any other suitable material, and which is formed snugly over a'tubular metallic liner 2 which thus becomes a part of 'the barrel. y

, The body also includes a tapered tip portion i! having a metallic'terminal 4 through which the lead 5 is fed as it Wears away, and through which it projects suiiciently for use in writing; The barrel may be fitted with the usual springclip 6 for holding it in the pocket when not inuse. Thel liner 2 of the barrel projects beyond the upper end of the outer shell I to receive internally the metallic cup l which holds the rubber eraser 8 and to support externally the ornamental cap 9 which encloses the eraser. One or more bosses I0 may be pressed in the surface of the upper end portion of the liner 2 to afford a frictional grip to retain the capl 9. j' ,i

Disposed axially within the barreLand extending intol the tip'of the pencil, is a guide tube Il for the lead having a helical slot I2 which extends from a point near the end of the tube within' the tip 3 and throughout the remainder of its length, said slot being open at the upper end of the tube II adjacent the upper end of the barrel. Immediately outside the guide tube II there is shown a guide member in the form of a co-axial tube I3 which may be made from a flat sheet bent into curved form with its edges I4 brought into abutting relation, as seen in Figure 4. At the opposite side of the tube a portion of its Wall is olset to form a guideway I5 which extends longitudinally adjacent the helically slotted tube II.

A lead-propelling plunger I6 is slidably carried `in the guide tube I I and is provided with laterally projecting lugs II spaced apart in accordance with the pitch of the helical slot I2 so as to eX- tend through said slot and into engagement with the guideway I5 of the tube I3. At its upper end the tube I3 is anchored in the barrel by means of a metallic insert I8 having a smaller cylindrical portion snugly fitting the tube I3 and either' slottedor formed with an offset I9 (as shown) to 't around the offset portion of the tube which provides the guideway I5 and having a larger cylindrical portion 2S fitted tightly into the barrel liner 2. At its lower end the tube I3 is anchored in the barrel by means of a short tubular member 2I tted tightly into the extreme end of the liner 2 at 22 and swedged over, as seen in Figures 2 and '7. The other end of the member 2l is flanged inwardly and formed to t snugly over the tube kI3 engaging its offset portion and thus holding it against rotation in the barrel.

The helically slotted tube II is iixedly secured in the'tip. Its extreme lower end is thrust tightly `into the tapered terminal 4 and it is also held :fast by means of a tight bushing 23 whichY centers the tube Il in the metallic core 25 of the body portion 3 of the tip-the upper end of the metallic terminal 4 rtting tightly onto said core member 24 -is permanently secured thereto when the body material 3 is molded around the core 24. The upper end portion 25 of the core is of a larger diameter, suicient to receive within it the lower end of the tube I3 including its offset guideway portion, and the part 25 projects from the upper end of the tip into rotative engagement with the barrel in a bearing provided by the tubular part 2| with a bushing sleeve 2% interposed. In assembling the parts, after the body 3 has been moldedvupon the core 2d, 25the sleeve 2B is slipped onto the projecting part of the core 25 together with a washer 21, -and the extreme end of the part 25 is then flared over, as seen at 28, to permanently secure kthe sleeve 2S with its opposite end abutting the transverse shoulder 3@d of the tip body 3. The sleeve 25 is thus rotatable upon the core 25 but the latter is formed with outwardly stressed spring ears 29 which engage the inner surface of the sleeve 26 and provide a desirable frictional resistance to rotation of the tip on the barrel. When the tip assembly is inserted in the cylindrical member 2l the sleeve 26 ts tightly therein and serves to lock the tip said relative rotation of the parts'. In this manner the lead 5 may be forced through the terminal I into position for use by rotative adjustment of the tip and barrel, and when the supply of lead in the tube II is exhausted, the plunger It4 may be caused to travel in reverse direction toward the upper end of the pencil by reversing the relative direction of rotation of said tip and barrel.

`The plunger IS includes a portion IBa which extends `sufficiently beyond the upper lug I'I to insure that as a result of this reverse rotation the eXtreme end of the plunger will project beyond the open end of the barrel if the cap 9 and eraser 8 are removed. In fact, the travel of the plunger I6 toward this end of the barrel may serve to 'force the eraser and cap 9 from their normal Ipositions so as to remove them, or, at least, facilitatel their removal. Then, as the lugs I'I `are fed 'out'of the helical slot I2 the projecting portion 'Ita of the plunger may be readily grasped and the plunger removed to allow the breech-loading of a fresh supply oflead into Vthe open, upper end -of the guide tube II.

It may be remarked that this new lead need not be supplied in a single piece; it may consist of several short pieces, dropped into the upper end of the guide tube to makeup the requisite charge of fresh lead. Then, when the plunger I5 is replaced and fed downwardly, the lead will be projected through the tip I! as required.

To facilitate the replacement of the plunger I6 I providemeans by which the user may know the position of the yguideway I5 in the pencil barrel, and maybe able to position the lugs I'I properly with respect to it without attempting to peer into the open'end of the barreL The clip Iiv is located outside the barrel at the same side of the axis as theguideway I 5 and in substantially radial alignment therewith. and the end portion 16a of the plunger isformed with an additional-lug IIa aligned with the lugs I'I so that the user may know that'when thelug I'FL is arranged to project radially toward the side of the pencil which carries the clip Ii the lugs I1 will be aligned with they guideway I5 and will enter the latter readily as the plunger is pushed into place. Preferably the tube II with its helicalslot I2 terminates a short distance inwardly of the endof the tube I3 so that one of the lugs II may be first entered in the guideway I5 and then pushed into engagement with the end of the-slot I2 as the ltip 3 is slowly rotated. As soon as the rst lug I'I has been picked up by the helical slot, the plunger will be drawn into the tube II and into abutting relation with the upper end of the lead previously placed therein. It will be understood that the .lug I'Ia is positioned at such a distance from the lugs I'I that it 4will register in the helical slot as the plunger advances. Then, upon replacement of the eraser 8 and cap Il the pencil will be again ready for use.

'I'herparts are so dimensioned that there is an annular space between the inner surface of the liner tube 2 and the tube I3 to accommodate a supply of extra leads 50 as shown in Figure 4. In order to render this supply available the insert I8 is out away at 30 leaving openings through which the leads may be inserted for lling the magazine and removed, as required.

Figures l and 3 show a special construction of the cap S which permits it to be made an ornamental feature of the pencil. It is provided with a liner tube 3l vof thin metal, to which is applied a ne metal cap 32 formed, for example, of an alloy of gold. or silver. Or, if desired, the liner 3| and cap 32 may be integral. In either case, the main covering 33 will be'of Pyrolin or similar material, corresponding to that of the body I of `the barrel. This composition covering may be formed from a short section of tubing, which, when heated and forced into a mold over the liner 3! will assume the proper shape to t snugly around the liner and against the shoulder formed by the cap 32 leaving only the cap portion of the metal exposed.

Itniay be noted that in providing the fric-v tional resistance to rotation of the tip on the` barrel, the material of the part 25 including its spring ears 29 should be of a slightly different hardness from the material of the bushing 29 upon which itbears; preferably, the bushing may be of a somewhat harder grade of metal, for example, nickel alloy than the tube 25 with ears 29. This will insure a smooth action.

Figures 8 and 9 showamodified .construction for connecting the tip rotatably to the barrel. In this form the tubular core 35 is molded in the composition tip 3 in the same manner as the part 25 of Figure 2, but beyondthe shoulder 3a of the tip the core 35 is split longitudinally by several slots 35a and the portions intermediate the slots are sprung so as to bear outwardly against the inner surface of a sleeve 36 which is fixed in the barrel I by being forced into the tapering end portion of the liner 2. At the inner end the sleeve 36 is formed with an outwardly pressed bead 31 providing an annular'` channel into which the outwardly flared terminal flange 38 of the part 35 engages permanently but rotatively when said part is pushed into the sleeve 36 in the assembling. Thus the tip 3 is held securely onto the end of the barrell I with capacity for rotation thereon. The end portion of the helically slotted tube I I is held frictionallyin the tip 3 by means of an interposed tight bushing 39 inserted between the tube I I andthe reduced neck of the core 35. rotated byturning the tip 3 on the barrel to cause the plunger I5 to travel toward the tip for feeding the lead 5 therethrough or Atoward the opposite end of the pencil for removal to permit reloading with lead.

Figures l0 and 11 show the modied construci tion for anchoring the guideway tube in the barrel. The tube is indicated at53 formed with an offset portion 54 providing a guideway forthe lugs` I1 of the plunger I6. 'Ihe tube may be made of a piece of sheet metal, bent into shape, and including radially extending portions 55 which project from the guide-forming portions 54 and terminate in flaring margins 56; These parts, in turn, are anchored to lugs 2a struck inwardly from the cylindrical wall of the liner 2.

rIf `the pencil barrel is made of a molded tube 60 of synthetic material, but without a liner tube, it may be formed, as indicated in Figure i2, so as to t snugly around the offset portion 6I of the guide tube 52 and this portion may have :daring side walls 63 bywhich itis interlocked with the material of the tube 99 andv serves to suspend the cylindrical portion 'of the tube 52 in axial position therein. Adjacent this cylindrical portion the tube maybe chambered at 64 to provide a partially annular space, serving as a magazine for spare leads 59.

Figures 13, 14 and l5 present the application of our novel mechanism to a pencil of the bullet type, which is made comparatively short, and with a blunt, rounded nose, so that it may be carried conveniently and safely in the vest Thus the tube I I may be pocket; As shown, this pencil includes a metallic barrel 19 .open atthe upper. end to provide a ysocket 'II for the eraser 12 and its metallic carrier 13; At the lower end the ,barrel is swedged to ya smaller diameter, as seen at 14, where it fits snugly around a telescoping section 15 most of which is contained within the barrel 10 kwhen the pencil is in collapsed position. However, this section 15 may be drawn out' to extend the pencil to a convenient writing length, and a portion of the surface may be" knurled at`19. The telescoping. section may be held atany o-ne of three positions determined by the small bosses 15 adaptedV to engage the outeredge of the reduced part of Ythe barrel 10 to prevent it slipping back into the-barrel while in use. The bluntly rounded bullet nose 11 of the tube-15 may have secured in it a conical support'18 for the lower end o the helically slotted tube 19. The latter is further anchored by the insertion of a washer f 'ange 86 which may be a separate member per manently secured thereon, and whose outer periphery is non-circular. The barrel 19 is also made non-circular'in cross-section, as shown, it is .octagonal, so that the non-circular ange 89 will be held therein against rotation, and will thus serve to hold the slotted guide tube 82 in fixed positionwhen the bullet-nose of the tube' 15 is rotated for turning the helically slottedtube 19. By such relative rotation it will be'7 understood that the plunger 35 is caused to ltravel endwise for feeding the lead 8l and projecting it fromk the bullet-nose 11 yas needed.. Or, by reverse rotation, the plunger may be projected `from the upper end of thebarrel and removed to permit the insertion of a fresh lead or leads in the guidetube 19. The upper end of the tube 15 isslightly iared, and is interlocked with the peripheral portion of the flange 86 but with suffi# cient looseness to permit rotation of the tube 15 while the flange 89 -is held against rotation. Near its bluntly rounded end 11'the tube 15 may have abead 81 which will permit itto be grasped for drawing out the tube 15 into extended position, as shown in Figure 14. When thus extended it will carry with it the octagonal ange 85 within the barrel 19 to a limit determined by inwardly projecting bosses 88 formed in the wall of the barrel 19 and adapted to engage the ange 39. The mechanism will be operable for feeding the lead, whether the pencil is thus eX- tended to its full length or left in telescoped position, as shown in Figurel.

It will be evident that therotation of the helicarlly slotted tube II for feeding the plunger I6 need not be eiected by `turning the tip of the pencil, but that a portion of the barrel, such as a head portion, may be provided at the upper end and may be mounted rotatably with respect to the remainder of the barrel and attached toy the tube I I for turning it; Or, if desired, the longitudinally slotted guide member, such as the tube i3 of Figure 2, or the tube 82 of Figure 13 may bel rotated either by the tip or the head portion of the barrel whilefthe helically slotted tube is secured xedly in the barrel. One such re-arrangement of the elements is illustrated in Figures 16, 17 and 18, in which the barrel 90 is tapered down to meet the metallic terminal 9| through which the lead is fed and is engaged non-rotatively therewith. The inner end of the terminal 9| is threaded at 92 for connection with the end of the guide tube 93 which is shouldered at 94 and tted with a washer 95 bearing against the shoulder so that the terminal 9| may act as a nut to draw the tube 93 firmly into the tapered end of the metallic liner of the barrel 90. The washer 95 will engage the liner frictionally and with suiicient wedging action to insure that it will not turn in the barrel, but the cross section of the guide tube 93 and the opening in the' washer 95 may be non-circular to insure that the tube shall be locked against rotation in the washer. The helically slotted tube, however, is rotatively mounted in the tube 93 which serves as a bearing therefor. As seen in Figure 19, the upper end of the guide tube 93 is formed with a groove 96 and a hollow head member 91 having a reduced neck 98 is formed with a bead 99 at the end of said neck to engage in the groove 96 and thus retain the head longitudinally in its proper relation to the barrel l while permitting it to rotate about the axis of the barrel. Beyond the end of the guide tube 93 whose slot |00 opens toward the upper end of the pencil, the helically slotted tube extends for a short distance, and has secured to it a collar |0| having a helical slot |02 coinciding with the slot I2 of the tube The collar may be secured to the end of the tube in any effective manner so as to rotate therewith while the neck portion 98 of the head 91 is, in turn, fixed to the collar |0| as by indentations |03 engaging corresponding depressions in the surface of the collar |0|. It may be understood that the cap |04 will be tted to the head 91 so as to be removable longitudinally, but resisting turning on the head 91; thus the cap may be grasped for rotating the head to turn the helically slotted tube and operate the plunger therein. The annular space around the guide tube 93 may serve as a magazine for leads which are inserted through an opening |05 in the transverse wall of the head 91. Preferably, the metallic eraser holder |06 is formed with a boss |01 adapted to ll the opening |05 when the eraser is in place, and thus prevent the leads from working into the opening and being broken off at their upper ends by the rotation of the head 91 when it is turned for adjusting the plunger within it. This latter feature is in accordance with United States Patent No. 1,801,671, granted to Charles R. Keeran, and dated April 21, 1931.

We claim:

1. In a mechanical pencil, a body including a barrel part and a part col-axial with the barrel and rotatably connected therewith, a helically slotted tubular member and a longitudinally extending guide member, one of said members being rotatable by one of said body parts and the other member being rotatable by the other body part, together with a plunger having a laterally extending lug engageable with the helical slot and with the longitudinal guide sothat rotation of one of said body parts with respect to the other will feed the plunger in the barrel, both said helical slot and said longitudinal guide terminating at a substantial Idistance within the upper end portion of the pencil body, and being unobstructed to permit removal of the plunger therefrom and insertion of lead therein at said upper end, and said plunger including a portion dimensioned to project beyond the upper end of the pencil body while said lug is -still engaged in the helical slot, and means externally disposed on the body indicating the location circumferentially of the longitudinal guide therein, said projecting portion of the plunger being provided with means to indicate the' position of the said lug thereon to facilitate entering the lug into engagement with the guide when theplunger is inserted in the upper end of the pencil body.

2. In a mechanical pencil, a body including a barrel part and a part co-axial with the barrel and rotatably connecte-d therewith, a helically slotted tubular member and a longitudinally eX- tending guide member, one of said members being rotatable by one of said body parts and the other member being rotatable by the other body part, together with a plunger having a laterally extending lug engageable with the helical slot and with the longitudinal vguide so that rotation of one of said body parts with respect to the other will feed the plunger in the barrel, both said helical slot and said longitudinal guide terminating within the upper end portion of the pencil body, and being unobstructed to permit removal of the plunger therefrom and insertion oi lead therein at said upper end, and said plunger including a portion dimensioned to project beyond the upper end of the pencil body While said lug is still engaged in the helical slot, and means externally disposed on the body indicating the location circumferentially of the longitudinal guide therein, said projecting portion of the plunger having an additional lug positioned to register in the helical slot and extending laterally in the same direction as the first mentioned lug to indicate the position of the latter when 'it is inserted in the barrel and to facilitate engaging said lug with the guideway.

3. In a mechanical pencil, a barrel, a tip rotatable therein, a lead guide tube o-perably connected to the tip and forme-d with a helical slot opening at the upper end of the barrel, said barrel having a longitudinal guideway extending adjacent said helical slot and opening at the upper end of the barrel, a plunger having a lug extending laterally through the helical slot and into engagement with the guideway, whereby said plunger is movable by relative rotation of the tip and barrel and is removable at the upper end of the barrel to permit insertion of the lead therein, said plunger including a portion dimensioned to project beyond the upper end of the pencil body while said lug is still engaged in the helical slot, and a clip externally secured to the body and disposed to indicate the location of the longitudinal guide therein, said projecting portion of the plunger being provided with laterally extending means to indicate the position of the lug of the plunger so that alignment of said indicating means with the clip will facilitate entering the lug into engagement with the guideway when the plunger is inserted in the upper end of the pencil body.

4. In a mechanical pencil, a barrel, a tip rotatable therein and inseparably connected therewith, a lead guide tube held in the tip and formed with av helical slot opening at the upper end of the barrel, said barrel having a longitudinal guideway extending adjacent said helical slot and opening at the upper end of the barrel, and a plunger having a lug extending laterally through the helical slot and into engagement with the guideway, whereby said plunger is movable by relative rotation of the tip and barrell and is removableat the upper end of the barrel to permit the insertion of lead therein, said plunger having a portion dimensioned to project a substantial distance beyond the upper end of the barrel while the said lug is still en-A gaged in the helical slot to facilitate removal of the plunger and replacementthereof, together with means externally disposed on the body indicating the location of the longitudinal guide- Way therein, and means on the projecting portion of the plunger adapted to indicate the position of the said lug thereon to facilitate entering the lug into engagement with `the guideway when the plunger is inserted in the upper end of the pencil body. V

5. In a mechanical pencil, a barrel comprising a main section and a tip section telescopically engaged with eachother and adapted for rela-y tive rotation about their common axis, a lead guide tube having one end held in the tip section and formed with a helical slot, a guide tube coaxial with the helically slotted tube and having a longitudinal guideway extending adjacent said helical slot, means anchoring said last named tube against rotation in the main section of the barrel but securing it to the tip section for longitudinal movement therewith, together with a plunger -dimensioned to t in the lead guide tube and having a lug to extend laterally through the helical slot into engagement With the guideway, whereby said plunger is movable by rotation of the.` tip section relativelyto the main barrel section at any position of telescopic adjustment of the tip section in said main barrel.

6. In a mechanical pencil, a barrel comprising a main section and a tip section telescopically engaged with each other and adapted for relative rotation about their common axis, a lead guide tube havingy one end secured in the tip section and formed with a helical slot opening at the opposite end, a guide tube co-axial with the helically slotted tube and having a longitudinal gudeway extending adjacent said helical slot and opening at the end remote from the tip, means anchoring said last named tube against rotation 1n the main section of the barrel but securing it to the tip section for longitudinal movement therewith, together with a plunger ,dimensioned to it in the lead guide tube and having a lug to extend laterally through the helical slot into vengagement with the guideway, whereby said plunger ismovable by rotation of the tip section relatively to the main barrel section at any position of telescopic adjustment of the tip section in saidmain barrel, together with a removable closure for the upper end of the barrel to permit the insertion of lead upon removal of the plunger at said upper end of the pencil.

7. In the structure defined in claim 5, said main barrel portion being of non-circular crosssection internally, and the longitudinal guide tube having a non-circular flange at its upper end engaged against rotation in said barrel section, to-

gether with a flange on the upper end of the tip section rotatively interlocked with said flange of the guide tube to insure movement of said tube with the top section throughout the range of telescopic movement of the latter 'in the main barrel while permitting said tip section to rotate about its axis in the barrel. l

8. In a mechanical pencil, a two-part barrel Y the tip section in the main barrel.

9. In the structure defined in claim 8, said barrel section being of non-cirlular cross-section, and said mechanism including a lnon-circular anchoring element engageable in said barrel to hold a member of the mechanism against rotation while permitting it to travel longitudinally in the barrel through the range of telescopio movement of the tip section.

10.7In a writing implementa cap comprising a metallic base structure of tubular form having an outwardly offset portion, and a covering of molded plastic material xed to said base terminating at said offset to leavea part of the metallic structure exposed.

11. In a Writing implement, a cap comprising `a metalic base structure of tubular form with a metalic terminal forming an end wall for the cap and including an annular flange fitted over the tubular base portion, thus forming a transaxial shoulder, and a covering of molded plastic material xedlyencasingfthe tubular base structure and terminating atv said shoulder, leaving the terminal itself exposed.

12. In a` mechanical pencil, a barrel, .a head portion co-axial therewith and rotatable with respect thereto, a lead guide tube located axially in the barrel and secured to said head for rotation thereby, said tube being formed with a helical slot opening at the upper end through said head, said barrel having a longitudinal guideway extending adjacent said helical slot and also opening atthe upper end, and a plunger having a lug extending laterally through the helical slot and into engagement with the guideway, whereby said plunger is movable by relative rotation of the head and barrel and is removable at the upper end of the barrel and through the head to permit insertion of lead in the guide tube.

13. In the combination defined in claim 12, said longitudinal guideway of the barrel being formed in a tube anchored in the barrel adjacent the tip, said tube being inter-engaged with the head to prevent longitudinal separation of the head' and the helically slotted tube from the barrel.

14. In the structure dei-ined in claim 12, said`