US2509849A - Lead feeding and holding construction for propelling pencils - Google Patents

Description

May 30, 1950 F. voN ALLMEN LEAD FEEDING AND HOLDING CONSTRUCTION FOR PROPELLING PENCILS 2 Sheets-Sheet l Filed Dec. 9, 1947 F. voN ALLMEN LEAD FDEDING AND HOLDING CONSTRUCTION May 30, 1950 FOR PROPELLING PENCILS 2 Sheets-Sheet 2 Patented May 30, 1950 LEAD FEEDING AND HOLDING CONSTRUC- 'I'IUN FR PROPELLIIIG PENCILS Fritz `von Allmen, Geneva, Switzerland, assigner to Fabrique Suissede Crayons Garan DAche` asas S. A.,` Geneva, Switzerland, Va ccrpm'ation4 of Switzerland Application December 9, 1947, Serial No. 799,611

In SwitzerlandSeptember 10, 194,7`

l 8 Claims.

This invention relates. to` propelling pencils, and is particularlyconcerned` with improvements n'propelling pencils ofthe kind-comprising a cylindrical-.housing `'tapered at one end, a leadguiding tube providedA at. one end with-icon` movement of the lead-guiding. tube;`

very eiective.

Vance by.

lie-cannot that no longer be enga assemble it correctly.

Z through longitudinal slots in `the lead-guiding tube, which renders the manufacture of` this part somewhat, more expensive.

The present invention hasas its object toA pron vide a propelling pencil of thetype described,

part

i? tractible chuck jawswliich protrude Jfrom. the which is` equally `edective in operatonmbut obhousing at the tapered end.- thereofv and; are vates thel disadvantages enumerated above, subject to the action ora spring which tends-to Morespecicallythe invention has for its oby press the jaws into a seat pro-videdcin the` said ject to provide an improvedpropelling pencil of tapered end` of the housing,y whereby the said i the type described whereby advancement of the jaws are caused to grip lead ldisposed between` lead may taire place until it is almost entirely them, an operating member on .the lead-guiding used. tube and protruding :from the housing at the end According to the `present invention, 1the irnopposite to the tapered end` thereof, whereby the proved propelling pencil is characterised by the lead-guiding tube andthe chuck jaws maybe l5 fact that the auxiliary jaws are each positioned moved against the actionof the spring', and an between two adjacentnjasws ot the cont-ractible element `co-axial with the lead-guiding Stube and chuck and are lconnected to a radially resilient movable freely between two `extreme positions, sleeve, the arrangement being such that by coone of which is determined by a stop on the tube, operation with Athe interior wall of the tapered said element having auxiliary-:jaws connected end -of the housingsaid auxiliary jaws may be thereto by shank portionsand operating during caused to grip the lead during forward `Inovepart of the forward .movement of the learl-guidment or the sleeveand to irictionally engage the ing tube to grip the leadandretain :the same in housing,r to retain the leadin an advanced posian advancedV position duringipart of the return tion during part of the returnmovement of the lead-guiding tube eiected by the said spring. ln'propelling` pencils octhiskind, axalipres- The auxiliary jawsr may comprise convergent sure on the operatingmemben-such as a knob parts` adapted to engage frictionally with the protruding-froinithe end oi the housing, causes interior wall of'the tapered end of the housing advancement` of the lead to a predetermined and the release of-thelsleeve from rictional enextent and the operation thereof isgenerally gagement with the housing during return movement of the leadfguidingtube may be effected In the knownconstructions or pencils of this by engagement ofi-an `enlargement ofthe chuck kind, however, the auxiliary-jaws which retain jaws including l an externally tapered the lead in an advanced position druing` part of adapted to engage the said sleeve for eiecting the return movement, or `the .lead-,guiding tube movement thereof` out ofk engagement Awith the which takes place onrelease of axial pressure on said tapered endof the housing-l theoperating member,- are arrangedentirely at The inventionis hereinafter described,l by way the rear ofthe contractible chuck jaws andthe of example,withreferenceito the accompanying shank portions connectingA there to. the lead.- diagrammatic drawings, in which:- guiding `tube.- Consequently, once the,remainingr 40 Fig, 1 is a side elevation, partly in section, il length o the leadloecoirues` shorter than the lustrating one.iembodiment` of propelling pencil length-of the chuck jaws,` including the shank according to the;4 invention,` showingthe load portions mounting thereoi, plustheuaxial grippedfbetweenthe chuck jaws; distanceof` displacement ofthe .auxiliary jaws, Fig.,2 is asimilar. viewshowingr the chuck itiisino-,longer pcssibleto cause the lead to ad,- jaws in the extreme adyancedposition wherein the operating membert W the auxiliary jaws gripfthclflead; i this -occursthe user may think that the` .mecm Fig. -3 is a similar viewshowing the position anismfor the-advancement has gone wrong, as occupiedby. the -partsnuring `the return moverear oi thelead can ment-of` the voperating memloef;- Ol y,.theauxiliary jaws. ln Fig. 4 is a view: in. perspective showing the some cases, willtnen dismantlethe propelrelativedisposition of the ,chuck` jaws and the ling ypencil in an endeayiour to cause it to function auxiliary jaws; and i agaim in anormalimanner,` but cannot always Figs. 5,` o and 7 are .part longitudinal sections on a larger scalesiniilar to Figs. 12 and 3 re- Moreover, theeimiary jaws .engagethe lead spectively, illustrating, a modification.

The housing I of the propelling pencil having a cylindrical inner wall is formed with a tapered end which is provided with an internal tapered seat 2. A lead-guiding tube 3 carrying at one of its ends spring chuck jaws 4, is subject to the action of a spring 6 which engages an annular ange 5 on the tube 3 and tends to hold the jaws 4 against the seat 2, which thus co-operates with the front part I5 of the rearwardly tapered part IE-Il formed by the exterior surface of the tapered shank portion of the jaws l. The lead-guiding tube terminates at its other end in a push-knob 'I protruding from the housing I.

The shank portions of the chuck jaws 4 extend from a part I screwed to the tube 3 and on the sleeve 8 converging arms forming auxiliary jaws 9 are provided, each jaw 9 being positioned be tween two adjacent jaws 4 of the chuck. The sleeve 8 is freely movable in relation to the chuck jaws 4 between two extreme positions, one of which is determined by stop means, such as the part I0, associated with the tube 3, and the other by the externally tapered or enlarged part of the chuck jaws 4. The sleeve is provided with longitudinal slots II to secure radial resilience. The auxiliary jaws 9 converge towards the front ends and are adapted to co-operate with the interior wall of the tapered end of the housing towards the end of the forward movement of the lead-guiding tube so as to cause the jaws 9 to grip the lead and to engage the sleeve 8 frictionally with the housing I for retaining the lead in an advanced position.

In Fig. 1, the parts of the propelling pencil are shown in the working position, the lead I2 being held tight by the jaws 4 which are caused to contract by the action of the spring 6 in the direction F, which draws the front part I6 of the rearwardly tapered part of said jaws 4 into the seat 2.

The propelling pencil hereinbefore described operates in the following manner:

In order to cause the lead to advance, axial pressure is exerted in the direction M on the push-knob 'I against the action of the spring E in order to bring the parts of the propelling pencil into the position shown in Fig. 2.

The push-knob 'I moves the lead-guiding tube 3 and the jaws 4 until the part IG comes in contact with the rear edge 50 of the sleeve 3. Thereupon, on further displacement of the knob 1, the sleeve 8 is moved axially and the jaws 9 come into contact with the interior wall 2l of the tapered end of the housing which progressively stops axial movement of the sleeve accompanied by radial contraction thereof so as to cause the jaws 9 to grip the lead I2 at the same time as the jaws 9 become wedged in the tapered end of the housing.

The lead I 2 is advanced in the same degree as the push-knob 'I because, during the forward travel of the latter, it is carried along by the shank parts of the jaws 4, said shank parts exerting sufcient radial resilient pressure to engage the lead frictionally.

When pressure on the push-knob I is released, the spring '6 effects the return movement of the lead-guiding tube 3 and of the jaws 4 in the direction F. During the rst part of this return movement, the sleeve il is held by the wedging of the auxiliary jaws 9 against the interior wall ZI of the tapered end of the housing. These jaws therefore hold the lead I2 in the advanced position to which it has been moved by the action of pressing the knob l', while the jaws 4 slide on. said lead.

In the second stage of the return movement' (Fig. 3), the rear part I1 of the effective tapered. part of the jaws 4 engages the front edge I4.l of the sleeve 8, so that this latter is disengaged from the interior wall 2l and moved in the di-` rection F. The auxiliary jaws S disengage au-y tomatically from the lead owing to the radiali resilience of the sleeve 8.

Finally, in the third stage of the return move*- ment, the front part I6 of the rearwardly tapered-v part of the jaws 4 again co-operates with the` seating 2 of the housing I in order to bring about the eiective gripping of said jaws on the leadi I2, the lead-guiding tube 3 being thereby arw rested.

The parts of the propelling pencil are then again in the working position shown in Fig. 1.

The propelling pencil hereinbefore described, although it comprises a small number of components, as compared with known pencils, functions very reliably. None of the components, which are of the simplest form, require precise machining. Furthermore, assembly is easy, so that the improved propelling pencil is inexpensive to manufacture.

The lead I2 can be advanced in the manner described until it is almost completely used up.

In view of the fact that the annular space between the lead-guiding tube 3 and the interior wallof the housing is free above the flange 5, it is possible to provide in this space a lead chamber communicating with the lead-guiding tube.

In the modication illustrated in Figs. 5, 6 and 7, the inner wall of the tapered end of the housing I has, between two conical bores 22 and 23, a cylindrical bore 24 of which the effective diameter is slightly smaller than the external diameter Dof the sleeve 8, as can be seen in Fig. '7, this sleeve terminating at the rear end in an annular edge 25. The unit formed by the sleeve 8 and the auxiliary jaws 9 is of substantially the same form as that described inconnection with Figs. 1 to 4. The lead-guiding tube 3 has a stop in the shape of a cylindrical extension 26 and the chuck jaws 4a have, where they are fixed to the lead-guiding tube, a collar 2l the diameter of which is approximately the same as the internal diameter d (Fig. '7) of the sleeve 8, said collar 2'! serving to locate the sleeve 8 co-axial with the extension 2E. As in the ernbodiment described above, the jaws 4a comprise on their exterior surface two rearwardly tapering parts, a front part Ilia and a rear part I'Ia.

The spring 6 acting upon the flange 5 of the lead-guiding tube 3 and, through this, on the jaws 4a rests against a fixed annular stop 28 in the interior wall of the housing l.

In order to advance the lead, the knob (not shown) is pressed to move the lead-guiding tube 3 and the jaws 4a from the working position (shown in Fig. 5) to the position of maximum advancement (shown in Fig. 6) in which the jaws 4 are opened. During this forward movement, the extension 26 pushes the sleeve 8 in the direction M by engagement with its rear edge 25, the collar 21 being already engaged in the sleeve 8 to locate the same. By the axial pushing action in the direction M the engagement of the part 4i! of the sleeve 3 with the conical part 22 eiects resilient contraction of the sleeve which is maintained by the engagement of the part I D with the cylindrical part 24 of the inner wall so that the auxiliary jaws 9 are pressed rmly against segscogeeo rnovement to eiect alpositive 'feeding 'of the lead. Movement ofthe auxiliary'jawst is eventually arrested 'owing to `the fact that theycome into 'contact withthe extremity of the small diameter of the conical'part`23 at lN (Fig, 6). The maxi- ?mumftravel'carried outby'the lead IlZ'andthe jaws fiaisindicatedata (Fig. v5).

At the beginning of the 'returnmovement of "the'l'eadfguidin'g tube 3 and thejaws 4a infthe di- -ie'dtion of 'the'arrowF under thelinfluence of the spring `[i the sleeve with'the auxiliary jaws9 Tfrmai'ns held 'securely bythe resilient 'contraction in'the "part 24 ofthehousing, 'so that the lead I2 `retains its ladvanced position, although the jaws 34a have'inoved back. Towardsthe end of the returninovement;therear taperingpart I'la of *the Ijaws "4a"`strike's`thefrontedge |41 of the sleeve' and causes "the Aeventualrel'ease of the auxiliaryjaws 9, since the partdeoi the sleeve 8 is broughtfback intoth'e conical part 22 of the Ahousing in the direction of its 'increase in in- 'l'ternal diameter (Fig. 7) While this release of the auxiliary jaws 9` takes "place, thelead is 'moved `-backtoia 'slight "extent untillthe front part I 8a of "the jaws engagestheseating 2 oft-he'housing, -lu'lhichinreases'thegrip f said'jawson the lead "I2 'and"therebyarrests the lead 'and its guiding tubefas in theeiribo'dimert Yfirst described above. Having' been moved back over this small distance, "the lead izfhas; in fact,'advariced'by the distance Ae "(Fig. "7), i; e. the difference between the maxirhum advance a, andthe` extent of its `last stage ofilthei returnmovement df the jaws da, from the "posi-tion shown in Fig. 'l tothat shown in Fig. A5.

`l. A propelling pencil comprising a 'housing 'having atapered 4end including a seat, fa lead- Yguiding tube vaxially slidable in -sa-idhousing for positioning alead co-axially with said tapered end, an operating member on the said tube and projectingfrorn theend of the housing opposite to" the said tapered end, a contractible lead-gripping chuck protruding thrcughvthe said tapered Vend of the housingiand comprising multiple jaws having shank portions'extendingfrom an abutment'associated 'with *the adjacent end of the lead-guiding tube,"`sai'd jaws having an enlarge- `'nient including a rearwardly tapered part for cooperation with said seat, `a spring acting to press Vthe saidlead-gding tube rearward to draw said chuck jaws intothe said seat whereby said jaws are caused to gripalead, and a sleeve elenient on the'saidfshank portions relatively mov- 'able in the axial direction, the relative move- `ment f saidsleeve beingllimited'in one direction the said enlargement ofsaid jaws andin the other direction'by the said abutment, sai'd sleeve `element alsohaving auxiliary Vjawseach positioned'between two adjacent chuck jawsto project for engagementiwith the inner fwall of said rtapered end, andlbeing radially resilientso that, kduring forwardmovement of the'lead tube resultinglin expansion of Said cotractible Chuck, thesaid auxiliary jaws arecaused t0 engage'the lead by co-operation of the' said sleeve withthe tapered end of thesaid `housing,and so'that, during part of the return movement of'the said `lead-guiding tube, thesaid Asleeve"isfrictionally held in said housingto'retain the leadin advanced position while the said chuck jaws are retradted towards' said seatto again 'grip the lead.

'2. 'A propelling pencil comprising ahousing 'a" tapered i end lincluding 'a seat, a leadpositioning a. lead cio-axially withzsairi 'tapered end, l a'n operating member Ton the :said "tube and projecting l from the 'end of #the housing opposite to the said tapered end, a contractible leadgripping chuck protruding through "the .said tapered end of the `housing andcomp'ri'singmulfor cooperation with said seat, asprin'g" acting-to press the saidlead-g'uidingtube rearward to draw s'aid'chuck jaws into the said seatwhereby said jaws are causedtofgripa lead,`arida sleeve ele- `nient onthesaid shank-portions relatively movable in theaxial direction, the relative movement of the said sleeve being limited -inlonedirction bythe said'ienlargement f said jaws and in the other direction byfthe saidabutrnentpsaid Sleeve `element ualso having auxiliary 'jaws each posi- `tioned between two adjacent chuck jaws and having externallylconvergentfparts for co-operation'withfthe interior of the tapered end of said housing, saidsleeve being radially'resilient l sothat, during fforwardniovement vof thelead tube resultingin expansionof `said contractible chuckith'e saidauxiliary'jaws areicaused to en- 4gage the lead byco-operation-ffthe said externally convergent'fpartswith the inner wall of thetapere'd end ofithesaid housing, and so that; during part offthe'retuiin movement fthe "Said lead-guiding `tu'be,"tl1`esaid'sleeve is=frictionally :held insaid housing to retain the lead `in advanced :position Ywhile "the 'said chuck jaws areretracted towards said 's'eat to again grip'the lead.

B. YA propellin'g -`pencil comprising a Vhousing having a tapered '-end 'including a seat, a lead- Sguidingtube 'axially' 4slidable in 1Asaid i housing for .f'positioning a lead cio-axially withsaid `tapered end, an operating member on the `said tube and fprcjectingfroni the endof the housing'ppposite to the said tapered end, a contractible lead-grip- -ping chuck protruding` through the said tapered fend ofthehousing"andfcoinprisin'g finultiplejaws having! shank portionslextending from one abutfm'ent aSsociated withtheadjacent endfo'fthe lead-guiding tube;` said ijaws having an4 `enlargemerit including a rearwardly tapered -part vcooperatin'g fwith saidtfseatlan'd a `rear externally tape'redpartfforming another abutment, a spring acting to press `the said-'lead-guidingtube rearufard'tofdraw said chuck jawsintothe said seating whereby sai'djaws are caused to gripa4 lead, "anda sleevefeleinent onthe" said'fshank portions frelatively iinovable in `the axial direction, the

relative nioveiiierit f said sleevebeing limited iby'the said abiitinentsgsaid sleeve elen'ient also `har-.ting auxiliary `jaws:each positionedbetween `two adjacent ehuck jaws to proect'for 'engage- Anient within saidtapered `end'o'f saidhousing and being radially resilient so` that, during forward movement of the lead tube resulting in ex- 'pansionof said eontractible chuckjthe' said auxiliary jaws are engaged by said abutment associated withtheferid of the said tube and are 'thereby `caused'to engage the lead by co-operati'on 'of thesai'd auxiliary jaws with the tapered ofthe vinner ir-'all of said housing, and sothat, during partof the` return* movement of the said lead-guiding tube,- the *said s'leeve' is frictionally held'i'n said 'housing fto ietaintheflead in ad- `vancsd position while the said `chuckjaws `are retracted Atowards said seat "to 4again Lg'rip the i lead,1 ian'd -iintil saidabitrnent "on-i said? chuck jaws engages said sleeve to move the same out of engagement with the inner wall of said tapered end of the housing to release the auxiliary jaws from the lead.

4. A propelling pencil comprising a housing having a tapered end including a seat, a leadguiding tube axially slidable in said housing for positioning a lead co-axially with said tapered end, an operating member on the said tube and projecting from the end of the housing opposite to the said tapered end, a contractible leadgripping chuck protruding through the said tapered end of the housing and comprising multiple jaws having shank portions extending from an abutment associated with the adjacent end of the lead-guiding tube, said jaws having an enlargement including a rearwardly tapered part cooperating with said seat, a spring acting to press the said lead-guiding tube rearward to draw said chuck jaws into the said seating whereby said jaws are caused to grip a lead, and a sleeve element on the said shank portions relatively movable in the axial direction, the relative movement of said sleeve being limited in one direction by the said enlargement of said jaws and in the other direction by the said abutment, said sleeve element also having auxiliary jaws each comprising a convergent part positioned between two adjacent chuck jaws to project for engagement with the inner wall or the said tapered end of said housing and being slotted longitudinally to provide radial resilience so that, on forward movement of the lead tube resulting in expansion of said contractible chuck, the said auxiliary jaws are caused to engage thel lead by co-operation of the said convergent parts with the tapered end of the said housing, and so that, during part of the return movement of the said lead-guiding tube, the said sleeve is frictionally held in said housing to retain the lead in advanced position while the said chuck jaws are retracted towards said seat to again grip the lead.

5. A propelling pencil comprising a housing having a tapered end including a seat, a leadguiding tube axially slidable in said housing ior positioning a lead co-axially with said tapered end and having an intermediate external flange, an operating member on the said tube and projecting from the end of the housing opposite to the said tapered end, a contractible lead-gripping chuck protruding through the said tapered end of the housing and comprising multiple jaws having shank portions extending from an abutment member detachably connected to the adjacent end of the lead-guiding tube, said jaws having an enlargement including a rearwardly tapered part cooperating with said seat, a spring disposed between said external flange and said tapered end of said housing and acting to press the said lead-guiding tube rearward to draw said chuck jaws into the said seat whereby said jaws are caused to grip a lead, and a sleeve element on the said shank portions relatively movable in the axial direction, the relative movement of said sleeve being limited in one direction by the said enlargement of said jaws and in the other direction by said abutment member, said sleeve element also having convergent arms forming auxiliary jaws and projecting for engagement with the inner wall of said tapered end, each of said auxiliary jaws being positioned between two adjacent chuck jaws and being radially resilient so that, during forward movement of the lead tube resulting in expansion of said contractible chuck, the said convergent arms co-cperate with the said tapered end of the said housing whereby said auxiliary jaws are caused to engage the lead, and so that, during part of the return movement of the said lead-guiding tube, the said sleeve is frictionally held in said housing to retain the lead in advanced position while the said chuck jaws are retracted towards said seat to again grip the lead.

6. A propelling pencil comprising a housing having a tapered end including a seat, a leadguiding tube axially slidable in said housing for positioning a lead co-axially with said tapered end, an operating member on the said tube and projecting from the end of the housing opposite to the said tapered end, a contractible leadgripping chuck protruding through the said tapered end of the housing and comprising a tube split longitudinally to provide multiple jaws having shank portions separated by slots and connected to an abutment member screwed to the adjacent end of the lead-guiding tube, said jaws having an enlargement including a rearwardly tapered part cooperating with said seat, a spring acting to press the said lead-guiding tube axially to draw said chuck jaws into the said seat whereby said jaws are caused to grip a lead, and a sleeve element on the said shank portion relatively movable in the axial direction, the relative movement of said sleeve being limited in one direction by the said enlargement of said jaws and in the other direction by the said abutment member, said sleeve element also having convergent auxiliary jaws each positioned in one of said slots between two adjacent chuck jaws and having longitudinal slots extending alternately from opposite ends to provide radial resilience so that, during orward movement of the lead tube resulting in expansion of said contractible chuck, the said convergent auxiliary jaws cooperate with the inner wall of said tapered end of the said housing whereby said auxiliary jaws are caused to engage the lead, and so that, during part of the return movement of the said lead-guiding tube, the said sleeve is frictionally held in said housing to retain the lead in advanced position while the said chuck jaws are retracted towards said seat to again grip the lead.

7. A propelling pencil comprising a housing having a tapered end part including an end seating at its extremity and an internal tapered seat communicating at its small end with a cylindrical bore terminating in an annular abutment, a lead-guiding tube axially slidable in said housing for positioning a lead co-axially with said tapered end and having an annular extension, an operating member on the said tube and projecting from the end of the housing opposite to the said tapered end, a contractible lead-gripping chuck protruding through the said tapered end of the housing and comprising multiple jaws having shank portions extending from a tubular element tted within the said annular extension of the lead-guiding tube, said jaws having an enlargement including la rearwardly tapered part (3o-operating with said end seating, a spring acting to press the said lead-guiding tube axially to draw said chuck jaws into the said end seat whereby said jaws are caused to grip a lead, and a sleeve element on the said shank portion relatively movable in the axial direction, the relative movement oi said sleeve being limited in one direction by the said enlargement of said jaws and in the other direction by said annular extension of the said tube, said sleeve element also having auxiliary jaws each positioned between two adjacent chuck jaws and being radially resilient so that, during forward movement of the lead tube resulting in expansion of said contractible chuck, the said auxiliary jaws engage said internal tapered seat whereby they are caused to grip the lead resiliently and thereafter slidably engage the said cylindrical bore to maintain grip on the lead during further forward movement, and so that, during part of the return movement of the said lead-guiding tube, the said sleeve is frictionally held in said housing to retain the lead in advanced position While the said chuck jaws are retracted towards said seat to again grip the lead, during the latter part of said return movement, the said auxiliary jaws being moved by said chuck to disengage from said cylindrical bore to release the advanced lead.

8. A propelling pencil comprising a housing having a tapered end part including an end seat at its extremity and an internal tapered seat communication at its small end with a cylindrical bore terminating in an annular abutment, a lead-guiding tube axially slidable in said housing for positioning a lead co-axially with said tapered end and having an annular extension, an operating member on the said tube and projecting from the end of the housing opposite to the said tapered end, a contractible lead-gripping chuck protruding through the said tapered end of the housing and comprising multiple jaws having shank portions extending from a tubular element fitted into said annular extension, said tubular element having an external collar projecting at the lower end of said extension and said jaws having an enlargement including a rearwardly tapered part co-operating with said seating and an abutment, a spring acting to press the said lead-guiding tube rearward to draw said chuck jaws into the said end seat whereby said jaws are caused to grip a lead, and a sleeve element on the said shank portion relatively movable in the axial direction, the relative movement of said sleeve being limited in one direction by the said abutment of said chuck jaws and in the other direction by said annular extension of the said tube, said sleeve element also having auxiliary jaws each positioned between two adjacent chuck jaws and being radially resilient so that, during forward movement thereof, by engagement of said annular extension with the end of said sleeve positioned by said collar, the said auxiliary jaws engage said internal tapered seat whereby they are caused to grip the lead resiliently and thereafter slidably engage the said cylindrical bore to maintain grip on the lead during further forward movement, and so that, during part of the return movement of the said lead-guiding tube, the said sleeve is frictionally held in said housing to retain the lead in advanced position while the said chuck jaws are retracted towards said seat t0 again grip the lead, during the latter part of said return movement the said auxiliary jaws being moved by said chuck to disengage from said cylindrical bore to release the advanced lead.

FRITZ voN ALLMEN.

REFERENCES CITED Name Date Bussler Nov. 6,. 1888 Number

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