US2510312A - Mechanical pencil with step-bystep push feed - Google Patents

Description

June 6, 1950 E. c. HEDLER MECHANICAL PENCIL WITH STEP-BY-STEP PUSH FEED Filed Feb. 7, 1946 2 Sheets-Sheet 1 iNvENTOR.

llll Edwin 6. Hed/Pr ATTORNEY June 6, 1950 E. c. HEDLER 2,510,312

v MECHANICAL PENCIL WITH STEP-BY-STEP PUSH FEED Filed Feb. 7, 1946 2 Sheets-Sheet 2 /ae @G 84 7o n W 7L. l

4. I; m \\\m@ sa) \o A 'A TTORNEY atenteci june 6,

umn-sn STATES PATENT omas MECHANICAL PENCIL wrrrl STEP-BY- s'rEP PUSH FEED Edwin C. Hedler, Chicago, Ill.

Application February 7, 1946, Serial N0. 646,104

This invention relates to an improved and positive type mechanical writing device particularly adapted to so called lead or graphitic writing devices or pencils but obviously having other -uses and extensions within the knowledge and skill of one working in this art. More specically it relates to a magazine type of an automatic pencil that is adapted to hold a plurality of leads and which positively dispenses each lead individually of a proper and suitable length for writing without breakage, jamming or other diiculties inherent in the present type mechanical pencils of the step-by-step or push feed type.

It therefore is an object of this invention to provide an veiiicient mechanism having few parts and economical to produce. It is further characterized by its ease of assembly and ability to utilize even small leads that may be inadvertently broken in the magazine.

These and other objects, ada-ptations, uses, modifications and variations will be readily apparent to one skilled in this art particularly in View of the lucid, denite and detailed description of the mechanism, the parts thereof and the fundamental elements underlying the principles involved in this invention as given hereinbelow and illustrated in the attached drawings forming a part hereof.

In the drawings,

Figure 1 shows an axial elevation of the pencil partly broken away.

Figure 2 is aY somewhat similar but partly broken away elevation showing the lead clutch opening means in greater detail.

Figure 3 shows an elevation somewhat similar as Figure 2 but showing the clutch in full engagement.

Figure 4 shows in an enlarged detailthe lead gripping or iclutch means in an open position.

Figure 5 is a section enlarged showing the lead alignment tube details and its relationship to the tip,

Figure 6 is a plan view of the clutch jaws in a closed position. Figure '7 is a similar view wherein the jaws are shut about a lead while Figure 8 shows a similar View to Figure '7 but but with the jaws in the open position.

Figure 9 is a sectional view of a modication of the clutch device or means while Figure 10 is an end view of the clutch jaws taken along lines III-IIJ of Figure 9.

f Essentially the pencil consists of an outer barrel or Ypencil case proper, I0, made of plastic, metal or some other suitable and desirable material.

12 Claims. (Cl.v 120--17 which the pencil lead 2B, protrudes when in a writing position. The tip I2, is preferably of metal and contains therein a number of slots to form spring-like segments I4' to grip the lead and prevent it from rotating about whenthe pencil is used. These segments I4 (all not shown in Figure 1) form a bore about the lead 2t. Within the bore and at the upper part of segments Iii, is an annular shoulder or collar lil, which is an integral part of the segments. rlhe floor of this shoulder slopes downwardly to provide a slide for the lead 2), as it moves forward under the urging of the propulsion unit shown in detail in other gures. Furthermore, it provides space for the segments I4 to operate in for they have induced spring characteristics which grip the lead 20. n j f The guiding and gripping portion lf3 of the tip is press fitted or molded into place in the tip I2. The tip I2 may be made from the same material as the barrel or case proper IIJ, or if it is desired may be made from another. The tip I2, by means of a male thread, I3, fits into the internal thread on the lower part of the tube body It, and thus completes the lowervoutside surface fof the pencil.

In the upper part of the tip I 2, and substantially coaxially located within the perimeter bounded by the threads I8, is an annular chamber 22. The

upper part of the chamber 22 is threaded with threads 24, which receive the threads 26. The latter are an integral part of the collared guide sleeve 28. However, both threads may be omitted or rim 32,' can move smoothly and freely withinl it thru a predetermined distance. This movement and the amount of distance of travel is im-` portant for it controls the distance that the lead will travel while it is being propelled forwardly" by the clutch.

Within the upper end of the barrel tube It, there"l is concentrically mounted an actuating or push;- tube at. Push tube 4i! has on its upper end a frictionally engageable button 34. Attached to the said button 34 is an eraser 36, made of rubber;A

factice and the like, snugly tted within the bore of the pus-h tube 40. Reserve leads or extras 2l! are disposed about in the magazine chamber 38.

The barrel II), ends in a tip I2, thru 5 5 Magazine chamber 38 has a sloping floor 42,

which centers and guides the lead 2B to a centrally located orifice 44 within the expander or wedge means 46. Both the sloping floor 42 yand the orifice or opening 44 are an integral part of the expander means 46.

In order to obtain a more perfect alignment of the entire mechanism, the expander means 46 has an outwardly projecting shoulder or rim 48. It is desirable but not essential that this shoulder be mounted about the midpoint since it was found that the greatest stability in action is obtained at this position. The base of the actuating tube 4,!) is seated on a part of the said projecting rim 48 while the balance of it is occupied to function as a restraining shoulder on the abutment 50 formed by stepping at the desired position the interior of the body barrel I0.

The lower portion of the expander body 46. is provided with a stepped shoulder 52, which rests on an annular pressure guide sleeve or washer 54. This guide 54, in turn rests on the spring 56. The lower end of the spring in turn rests on the collared guide sleeve 28. A tube 36, is press fitted over or otherwise rmly secured to the collared guide sleeve 28. The upper edges of the tube 36 are preferably turned inwardly to form a retaining shoulder over the guide sleeve 54. This tube 30 retains in place the spring 56, which forces apart the key wedge 58 and the wedge retaining wall 62. The key wedge 53 is preferably an integral part of the expander body 46.

YThe lower part of the expander means 46 terminates in a particular type of a tapered wedge or key 58. This key is so constructed as to the degree or angle of its taper that it frictionally engages the interior of the wedge retaining walls 62 of the gripping members 64 that are operating on the leads 20.

This angle or degree of taper is the acute angle included by the sloping walls of the key and an imaginary vertex located on an imaginary vertical line extended perpendicularly and coaxially thru the tube or barrel I of the pencil. It was found that this wedge must have an angle as defined above within the limits between two and forty degrees. For most practical resultsit is preferred to use an angle in the range between four and six degrees.

Though it is preferred to use a wedge having a frusto-conical section, it is obvious that the shape may Vary over a wide range and still be within the spirit of this invention. For instance, the wedge may be a polygon having an elliptical, triangular, quadrilateral, pentagonal etc., conguration. It is preferred but not essential that the Wedge retaining walls 62, have the same degree of angularity and configuration as the wedge key 58 so as to provide the most effective angle of contact between the frictionallyengageable surfaces of the expander 46 and gripping members 64. However, it is apparent that any type of an openingin the chamber formed within the periphery of the wedge retaining walls 62, may be utilized provided the wedge key 58 can be inserted therein and is frictionally engaged by the said walls 62. Further, this angle will also vary with the nature of materials `used in the making of the mechanism, since the coefficient of friction of such materials will be considered in the design.

But regardless of the shape, the wedge key 58 must perform two functions; (1) it must open the jaws 64 ofthe clutch body 66 by pressing open the interior walls 62 thereof; and (2), it mustbe frictionally engageable with the said walls 62. Thus. in actual operation the entire clutch body 66 frictionally engaged by and suspended from the wedge key 58 is carried upwardly in an open position by the expanding movement of the compressed spring 56 until the stripper collar 32 on the clutch body 66 prevents further upward travel upon contact with shoulder 63. When this occurs the frictional bond between the wedge key 58 and the walls 62 is broken. The jaws 64 activated by the inherent inward spring tension induced in said jaws clamp or grip the lead 25 and thus remain ready in the position to repeat the feeding of the lead 26 to the tip I2 according to the operation described hereinbelow.

The clutch body 66 consists of a tubular member of a specific design and interior configuration. Though for economical and practical reasons, a cylindrical tubular member is desired, it is obvious that this shape may vary considerably and still be within the fundamentals of the principles as expressed by this invention. For instance, the clutch body member 66 may be triangular, quadrilateral, etc., or if desired any other shaped polygon capable of performing this function and capable of imparting a gripping action on the lead 26. As mentioned above the key or wedge 58 on the expander means 46 should preferably but not necessarily have the same contour as the tapered portion of the restraining faces 62 of the tubular member 66 so that the degree of frictionalengagement is of suiicient magnitude to insure proper function. Obviously, under these considerations it is desirable that the contour of both the wedge key 58 as well as the restraining faces 62, besubstantially similar, particularly when in full engagement. This frictional engagement obviously can be varied and when properly designed the actual force of this frictional engagement depends largely upon the lamount of inherent inwardly inclined spring tension within the jaws. This tension may be modified readily by changes inthe dimensions and contour of the clutch body 66.

At the lower end of the lowerguide sleeve 28 held in the tube 36, is located astripping means or shoulder 68. This shoulder 68 upon contact by the upwardly moving rim 32, causesdisengagement of the frictionally engaged faces. 62 from the wedge 58. This act per-mits the spring tensioned jaws 64 to close about and grip the lead 20.

The upper endof the clutch body 66 `is slotted into one or more segments 10. Each segment -10 has an inner sloping wall 62. which .as mentioned above preferably has the same. contour as the adjacent complementary face of the wedge 58.- The surface of the inner wall 62terrninates .as a stop shoulder or lip. 14. This lip 74 restrains. further entry movement of the key 58.`

The lip or stop :collar 14 preferably but not necessarily forms the upper part or head of vthe jaws 64. These jaws .64 arefso designedthata portion of the lead 26 is seized and gripped strongly therebetween when they are closed..- The clutch body 66 is tubular and preferably formed from spring steel. Slots 72 are cut therein to form a number of segments Tit.y These are formed in the untempered steel. tempering process, they are squeezed'. together and tempered in that position so that the spring characteristics are nducedand developed in the jaws 64.

Within the bore of the `clutch ybody 66 ,and below jaws 64' is along narrow'alignment tube I8 having an inner diameter slightly larger thanthe thickness of the lead 26 in-its lower portion@- The upper part 8i) of the alignment tube 18 isV Prior tothel slotted and slightly ared having one or more spring-like segments to retain the lead 20. The diameter of the bore of the alignmentV tube slightly below the flared portion 80 is slightly constricted to provide a means for gripping the lead by the spring tension provided within the segment walls. This particular feature prevents the accidental retraction of the lead, 26, when the jaws 64 should perchance become fouled with the wax coating scraped from the leads. The alignment tube 78 begins at a point in the hollow chamber below the jaws 64 and terminates above the slot I4 in the tip l2. This tube 18 retains the leads 28 or short sections thereof in perfect alignment so that they are not crushed or crumbled, thereby clogging and jamming the flow of lead 25 at any point of movement.Y

The operation of this pencil and the function of each part and its relationship to the other elements thereof will now be described.

The lead 20 lying in the magazine chamber 38 guided by the sloping floor 42 of the magazine chamber falls under the influence of gravity into the centrally located orifice 44. The orice has a slightly larger diameter than the lead 28 which under the influence of gravity drops thru the expander means body 46, into the wedge entry chamber formed by the walls 62. Here it comes to a stop on the wedge stop shoulder 'i4 of the clutch body 66 since the jaws 64 normally are closed. The inbuilt spring tension of the jaws 64 keeps these closed until they are opened so that the leads 20 can drop further under the vaction of gravity. The constricted portion of the alignment tube 18 prevents further drop of the leads 20 unless some positive force is used to drive them thru this constriction. Since this alignment tube is just below the jaws 64, itis obvious that even short pieces of lead 25 will be properly fed and held in alignment.

The application of pressure to the button 34, simultaneously transmits it thru the actuator tube 48 which slides concentrically within the pencil barrel or tube lll. The actuator tube 46 is press tted over the expander means body 46 and rests on the expander body collar 48. The applied pressure is then transmitted onto the collar 48 and to the taper wedge or key 58 which slides within the rolled edge of the retainer tube 30. Within the retainer tube 36 is a guide sleeve and pressure transmitting washer 54. A shoulder 52 preferably an integral part of the eX- pander means body 46 rests on the combination guide and washer 54. As the pressure is applied to the expander means body 46, it in turns bears down on the washer 54 which compresses the spring member 56. The spring member 56 at its lower terminus presses against the guide sleeve 28, which is screwed into or is slip tted in the tip I2.

At the lower terminus of the expander means body 4'6 is a wedge or key 58, having a slight taper of the type described above. This key 58 is suspended freely in the chamber bounded by the wedge key restraining walls 62. These as mentioned previously are preferably of the same contour as the complementary surfaces of the wedge 58. As further pressure is applied, the key 58 slidably moves downwardly into the chamber to contact the walls 62 and engage them in a frictional bond as shown in Figures 2 and 3. As still further pressure is applied the key 58 continues to move downwardly carrying with it the walls 62 and the clutch means body 66 of which the jaws -62 are an integral part. As this downward movement continues eventually the rim 32 :contacts the bottom of the .chamber 22 in the tip I2.-

This contact stops further downward movement of the clutch means body 66.*while the penetration of the wedge key 58 continues between the faces 82 of the jaws 64. The latter upon further penetration of the key 58 are pried apart to permit the lead 28 to drop thru into the alignment tube 18, which is nestled within the clutch means body bore. Since the top of the alignment tube 'I8 is flared and then slightly constricted at 86 to provide a lead holding spring tension, the freely falling lead 28 will come to rest at this point. In the meanwhile further downward movement of the wedge key 58 is prevented by the stop shoulders 'I4 on the top of the jaws 64. This concludes the downward movement of the entire assembly.

Upon release of the pressure exerted on the pencil top 36 the compressed spring 56 is released and snaps to return the entire assembly to its original position. However further upward movement of the clutch means body 66 is prevented by the bottom rim collar 32 which impinges on the clutch means body stripping shoulder 68. The wedge key 58, in the meantime, moves upwardly until stopped by the shoulder 50. The lead 20 being free of the jaw grip remains in the rest position. As soon as the clutch body 66 is stripped from the wedge key 58 the jaws 64 close tightly about another portion or another coaxial section of lead 28 and thus it is in position awaiting further downward action by the wedge key 58. When this occurs, the lead 26 held by the jaws 64 is` again pushed downwardly until the clutch means body rim 32 reaches the chamber 22 floor and again the jaws 64 are pried apart to leave the lead 28 free. This action is repeated until thel proper amount of lead is projected thru the friction segments of the pencil tip l2,

As mentioned previously, it is possible to have a number of variations of the clutch means and the components entering into its combination. For instance, Figure 9 shows another variation that can be readily made to serve this purpose. Figure 10 is a section taken along line ID-I D of Figure 9, thru the clutch jaws portion. Essentially it consists of a barrel body 66 having at one extremity the stripping shoulder 32 whose function was previously described. On the outer surface of the body 66 and about the proximity the clutch jaw area is an encircling spring band or split washer 84 riding in a groove 82. This washer holds under its spring tension the segments 'l0 of the body to-` gether so that the jaws of the clutch are in a closed position. The preferred type is the one: shownand consisting of a split spring washer on tube type. This type can readily be slipped overx the ends of the clutch body and also provides an! easy means for removal. The clutch body as,- shown consists of a barrel having two or mora slots cut into one end thereof to provide a series of segments. The jaws on the slotted segments which hold the leads 28 are prevented from opening by the restraining spring washer 84. However, when the wedge key 58 is forced between the surfaces 62, the spring washer 84 and the jaws 64 are spread apart and the lead is free to move. When the wedge is removed, the jaws close.

While it is obvious to one skilled in this art that many modifications, variations, extensions and adaptations are entirely possible, these nevertheless are considered within the scope and Spirit.AVA

7 ftiiffuridamentn principles-underlying thsiiie; ve'ntion: asl defined by the hereunto appended" claims'.

Ifclaim:

lL A( mechanical pencil-of the step-byf-steptype' comprising a barrel, a pointed tip lon one end ofsaid barrel, the said tip having therein'a bore'to receive leads, segments in pointed end of said tip formed by slotting the end of said tip, the said segments having inwardly induced resiliency to forma bore withinsaid end of slightly" smaller diameter than diameter of upper lead bore to provide 'a means to retard exit of the leads; means to` attach said tip to the said barrel, a chamber' above the` said means for retarding exitof leadsk through the tip, a lead gripping means mounted in'said chambenthe said lead gripping means comprising arsegmented tube, the uppermost portion of the inner-walls-thereof tapering inwardly and downwardly to form ac'o'nical hollow having an-A included angle of not more than forty degrises; lead gripping jawsv below said hollow, a co1- larl on the lower end of said tube inslidablecontactl with the walls of said chamber, a detent toengage' said'collar and to limit'the upward trave-ll of said leadgripping m'eans, an engaging and opening means comprising atapered key havingy a taper substantially coincidental with the taper orv saidco'nica'l hollow in uppermost part'fof the segmented tube, a spring means to disengagesaidl engaging'means, a' means to actua'te the said-engagingl andopening means, and a lead passage through said engaging and opening means incoaxialjuxtaposition with leadpassageof the? lead;

grippingmeans and offsaid tip.

2. In thel pen'c'ilof claim l, a -leadalign-in'g tubel extendingfromfapproximately the lower endof thesaid lead gripping jaws tov approximately the segmented portion of end of said tip.

32 The'pencilof claim 2, wherein the said' lead aligning means consists off an elongated tubehavingV throughout' its major portion a' bore slightly larger than the diameter of the leads', the upper? part of said aligning means having. a dared;-

slotted'segmented lead receiving cup; the'sectio'nimmediately belowand adjacent said iiared slottedv receivingA cup having a constriction thereinl formed by the: converging segments in the upper?- pa'rtfof the alignment tube, the said constriction h-avingaV diameter slightly less tharifthe diameter of said`v leads', a spring means inbuilt into saidl segmentsl of tube tov provide affiictio'nal gripping action.. on theleads,4 and the lowermost end'o'fsaid'` aligning. means terminating substantially near the said means for retardingeXit rer the leads.A

4e.' The' pencilof claim l, wherein the base'f ofA said 'spring actuating means comprises a` means' forlfguidinglleads to acentrally located bore; the iioorv offV saidmeansl for guiding leads slopingi downwardly to thes'aid centrlallylo'c'ated'bore, the said bore extending axially through'-Y the saidmeansfto engage and open thesaid ilea'd-f gripping Jaws;A

5;'IheVv pencilof' yclaim 1, wherein the saidfif' stantially; the same degree oftaperI as the-saidinner tapered surfaces forming the conical hol;V

low inthefsegm'ented tubei abovethe-lead grip;- pingjaws, whereby the sa-idsurfacescanfbe' en-l` gaged frictionallyon` substantialcontact`Y wth= eachother. f

6. The pencil of 'claim l, wherein the'said'lead gripping means' comprises a tubeelike element, theV lowerv end; of said tube-like element having thereon a detent, a means forming a part of said tip'assembly to stop further upward movement of said detent on the tube-like element whereby the movement of said lead gripping means is confined to a preselected distance, the upper part of said tube-like element having segments therein formed by slots cut into said tube-like element, each of said segmentsv characterized by inwardly inclined spring force of suflicient strength to retain leads therebetween and resist writing pressure on the leads, the uppermost portion of the interior wall surface of each of the said segments formed to dene a tapered hollow in the tube-like element, the said hollow being substantially the same in contour as the rel' lated portion ov themeans to engage and'open said lead gripping jaws.

7. 'I'he pencil of claim 6, wherein the said means to prevent further upward movement of the lead gripping means comprises a guide sleeve slidably mounted in chamber above the said means to retard exit of leads, the said guide sleeve having a bore su'iciently large to receive therethrough upper portion of said tube-like element', a flange on exterior of said guide sleeve to receive thereon the said spring means, and to prevent-downward movement of said guide sleeve.

8.v A sub-assembly for the pencil of claim '7, comprising a tube, a coil spring inserted therein, upper end of said tube turned inwardly to proL vide a'retaihingshoulder for said coil spring, the lower end-oi said spring-like coil resting on a guide sleeve, the upper end of said guide sleeve retained slidably within the said tube', and th'el lower end of saidtube turned inwardly to retain' the'slidable portion'of said guide sleeve.

9. In the sub-assembly of claim 8, a means within the upper part of said tube for coaxialv alignment of said engagement and opening means" with the said lead gripping means.

l0. Thep'en'cil of'claim i; wherein the said bar' rel has an annular shoulder and the engaging and opening means have an annular collar"k thereon to butt against each other when the said' engaging and opening means are forced apart by said spring means from said lead gripping; means, and to restrain further upward action of said spring.

1l. The pencil of claim l, wherein the said conical hollow has preferably an included angle from four tol sixdegrees;

l2. The pencil yofclai-m' 1, wherein the said lead-n gripping means comprises an elongated tube-like* -element, the upper part thereof having not'lesis" than two opposing vslots cut therein to lformrsegments, a meanson exterior of said slotted por#- tion to exert compressive and resilient pressure-- on said segmented wall sections and a means toretain said compressively acting'me'ans substantiallyV about the desired position.

EDWIN C. HEDLER.

REFERENCES CETED The following references are of record in the file of this patent:

UNi'rED STATES YPA'i'uirrrs Number Narn'e Date 1,759,931 Barberon- 1 May 27, 1930'w 2,222,295 Kanner Nov. 19, 1940V

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