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US3922098A - Mechanical pencil - Google Patents

Mechanical pencil Download PDF

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Publication number
US3922098A
US3922098A US423476A US42347673A US3922098A US 3922098 A US3922098 A US 3922098A US 423476 A US423476 A US 423476A US 42347673 A US42347673 A US 42347673A US 3922098 A US3922098 A US 3922098A
Authority
US
United States
Prior art keywords
lead
collet
mechanical pencil
half shells
shells
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US423476A
Other languages
English (en)
Inventor
Otto Katz
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Faber Castell AG
Original Assignee
AW Faber Castell GmbH and Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by AW Faber Castell GmbH and Co filed Critical AW Faber Castell GmbH and Co
Priority to US05/592,252 priority Critical patent/US3998558A/en
Application granted granted Critical
Publication of US3922098A publication Critical patent/US3922098A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B43—WRITING OR DRAWING IMPLEMENTS; BUREAU ACCESSORIES
    • B43K—IMPLEMENTS FOR WRITING OR DRAWING
    • B43K21/00—Propelling pencils
    • B43K21/02—Writing-core feeding mechanisms
    • B43K21/16—Writing-core feeding mechanisms with stepwise feed of writing-cores
    • B43K21/20—Writing-core feeding mechanisms with stepwise feed of writing-cores with writing-cores automatically replaced from magazines
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B43—WRITING OR DRAWING IMPLEMENTS; BUREAU ACCESSORIES
    • B43K—IMPLEMENTS FOR WRITING OR DRAWING
    • B43K21/00—Propelling pencils
    • B43K21/02—Writing-core feeding mechanisms
    • B43K21/04—Writing-core feeding mechanisms with the writing-cores brought into position by gravity
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B43—WRITING OR DRAWING IMPLEMENTS; BUREAU ACCESSORIES
    • B43K—IMPLEMENTS FOR WRITING OR DRAWING
    • B43K21/00—Propelling pencils
    • B43K21/02—Writing-core feeding mechanisms
    • B43K21/16—Writing-core feeding mechanisms with stepwise feed of writing-cores
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B43—WRITING OR DRAWING IMPLEMENTS; BUREAU ACCESSORIES
    • B43K—IMPLEMENTS FOR WRITING OR DRAWING
    • B43K21/00—Propelling pencils
    • B43K21/02—Writing-core feeding mechanisms
    • B43K21/22—Writing-cores gripping means, e.g. chucks

Definitions

  • a mechanical pencil of the collet action type is provided with a lead collet being formed from a pair of [52] U.S. Cl 401/94; 401/65 identically configured mating shells which are main- [51] Int. Cl. B43K 21/22 tained in fixed relation with respect to one another by [58] Field of Search 401/92-94, means of an annulus cooperating with a conical flared 401/65, 67 portion formed at one end thereof and by means of a cap at the opposite end, all parts of the pencil being [56] References Cited maintained in assembled relation by a spring.
  • the UNITED STATES PATENTS parts are assembled by sliding first one and then the 654 722 7/1900 Francis u U 401/93 other of the two collet shells through an annulus into 2353:177 7/1944 Moore 401/65 mating relation with one another and thereafter fitting 2,473,149 6/1949 Juelss 401/65 the end n ever the end of the mating Shells- FOREIGN PATENTS OR APPLICATIONS 10 Claims, 7 Drawing Figures 1,103,083 5/1955 France 401/94 Sheet 1 of 2 V all/Ff US. Patent Nov. 25, 1975 Sheet 2 0f 2 U.S. Patent Nov.
  • the present invention is directed to a mechanical pencil of the collet action type wherein a shiftable lead is carried within a collet which collet member is held in lead gripping relation by the effect of a compression spring and which is movable in opposition to the bias of the spring to cause the lead to be moved extensibly from the collet.
  • the lead has to be held firmly even after frequent releasing of the collet member so that with sufficient safety the individuals firm writing pressure can be absorbed without the shifting of the lead. It is desirable that the collet member clamping effect be achieved with as little prestress of the spring as -is reasonably possible and with a low spring constant in order to facillitate the operation of the depressable push button.
  • collet members have the disadvantage of requiring a considerable amount of assembly work and precise machining and are consequently relatively expensive to manufacture.
  • mechanically pencils are generally of high quality and are salable in particular markets (such as for use in the making of professional drawings) these pencils are generally too high priced to be used in the general market and particularly in the student market.
  • the lead collets consist of at least two collet shells which are joined together along at least one plane surface parallel to the axis of the pencil itself and the collet shells contain partially cylindrical recesses in the mating faces thereof with a radius which is substantially equal to half the lead diameter whereby to define a lead receiving passage.
  • the collet shells are formed of a thermoplastic material and each of the other parts of the pencil can likewise be formed of a plastic material except that the spring is most desirably formed of metal.
  • the pencil is designed with the two collet shells extending through an annular opening in the'tip end of the pencil housing in such a way that conically flared end portion of the shells is disposed in engagement with the annular tip end of the housing and grippingly engage the lead contained within the collet and the flared conical end of the collet is maintained in such engagement by means of a compression spring which acts against a collar carried on the opposite end of the collet member.
  • the collet member extends exterio rly of the housing and a cap extends thereover to join the two mating shells of the collet together and to provide a means for moving the collet member in opposition to the bias of the spring in order to spread the collet jaws to release lead for extensible movement from the collet.
  • Such a pencil is readily assembled by sliding first one and then the other collet shell through the annular opening at the tip end of the pencil and thereafter moving the two shells into congruence with one another and capping their opposite ends so as to join them together.
  • the spring can be maintained in its assembled relation by sliding a collar over the ends of the collet shells after the second shell is moved into congruence with the first and all of this can be accomplished without providing any threaded connection between any parts and by simply utilizing the annular opening at the tip end of the pencil housing and the single end cap as the means for joining the parts in assembled relation.
  • Roughened surfaces or elastic ribs of one kind or another can be formed at the tip end of the collet shells to provide an additional means for insuring a good frictional grip between the collet jaws and the lead itself.
  • the collet jaws with the conically flared external surfaces may extend only through a clamping ring fitted within the pencil housing rather than through an opening at one end thereof, but the concept of assembly and operation is essentially the same.
  • the lead extends further through a tubular opening formed in the tip end of the pencil housing itself and that opening may in itself have elastic ribs of one kind or another to insure a gripping relation between the pencil lead and the housing itself.
  • the assembly is essentially the same in that the two shells which are to define the collet member itself are placed in face to face engagement with one another but are maintained in a position axially displaced from one another while they are inserted through a clamping ring.
  • the clamping ring has an internal diameter which is smaller than the maximum diameter of the conically flared portion of the collet member (when the two shells are in congruence with one another) but which is greater than the combined cross sectional area of the flared collet shell at its widest point and the necked portion of the adjacent shell so that the two shells (when axially displaced) can be slid through the clamping ring. Thereafter, the two shells are moved into congruence with one another and the end cap at the opposite end of the collet member is placed over the two shell ends in order to maintain the whole arrangement in assembled relation.
  • a further object of the invention resides in the means of assembling a mechanical pencil of the herein described type in such a manner that the collet member can be entirely assembled and put in operative condition without requiring precise machining and without necessitating threading assembly steps.
  • FIG. 1 is a vertical sectional view through a mechanical pencil constructed in accordance with the principles of the present invention
  • FIG. 2 is a fragmentary perspective view of two collet half shells
  • FIG. 3 is a fragmentary perspective view of the gripping surface of a collet shell
  • FIG. 4 is a vertical sectional view through a mechanical pencil constructed in accordance with the principles of this invention but showing another embodiment thereof wherein one end of the collet member is maintained in assembled relation by a clamping ring and the lead extends from the collet member through the tip end of the pencil housing;
  • FIG. 5 is a horizontal sectional view through the mechanical pencil of FIG. 4 showing various parts during an assembly operation
  • FIG. 6 is a view of the assembly process wherein the identically configured collet shells are maintained in axially displaced position with respect to one another as they are inserted through the clamping ring;
  • FIG. 7 is a fragmentary vertical sectional view through a combined collet member and lead guiding tube.
  • FIG. 1 there is shown a housing 1 having a bore 2 formed therein along the axis thereof which bore has a radially enlarged portion at the upper end thereof and is stepped down as at 3 to a radially reduced tubular section.
  • a collet member indicated generally at 4 and consisting of two identically configured collet half shells 4a.
  • the collet half shells are formed of thermoplastic material and are plastically deformable and have outwardly flared conical end portions 5 and have a lead receiving passage 5a formed therein which open through a cylindrically configured slightly radially reduced section 6 thereof which, in turn, is provided with knurls or small ribs or elevations 7 for the purpose of providing an additional gripping effect on the lead 17 carried within the passage 5a.
  • a slightly outwardly flared collar 8 is provided which is of such a dimension that a slotted supporting ring 9 can be fitted thereover which, in turn, serves as a seat for one end of a compression spring 10 which is adapted to be interposed between the stepped shoulder 3 and the ring 9.
  • the spring 10 will serve to bias the flared conical portion of the collet member 4 into engagement with the annular end portion 5b of the housing 1 to cause the lower ends of the collet member (constituting the collet jaws to frictionally grip and hold the lead 17 in writing position.
  • the upper end of the two collet half shells are joined together in mated relation by an end closure cap 11 which is simply fitted over the ends of the two collet half shells and serves to hold them in proper assembled relation with respect to one another.
  • the upper end of the collet member and the end closure cap 11 extend exeriorly of the housing 1 in order to provide a means whereby the collet member can be depressed relative to the housing against the opposing bias of the spring 10 to move the conical section 5 out of engagement with the annulus 5b in order to cause the collet half shells to spread apart from one another and to permit the lead 17 to drop by gravity to a lower position within the passage 5a.
  • the lower end of the collet half shells are relieved as at 12a by small steps 12 in order to provide a means whereby the portions of the collet members below the steps 12 can be moved into engagement with the lead to hold it in fixed position.
  • the housing 20 is cylindrical in configuration and has a separable tip 23 threaded onto the lower end of the housing part 20.
  • a cylindrical bore 21 is formed within the housing 20 and is radially enlarged at the step bore shoulder 22 in order to provide the threaded part into which the tip 23 is fitted.
  • a plurality of elastic ribs 24 are formed within the interior of the tip 23 surrounding the tubular opening 24a in that tip in order to provide a simple means to frictionally engage the lead 17 and retard or brake its movement through the tip end of the pencil.
  • two collet half shells 4 are also provided which are configured identically to one another and which terminate at their lower end in flared conical portions 5 which then are necked down for a distance to the shoulders 14 formed on the collet half shells.
  • the shoulders 14 comprise a single planar seating surface (when the half shells are in assembled relation) in order to provide a seat for one end of the compression spring 10.
  • the compression spring 10 has its opposite or lower end seated, in turn, on a mounting ring 27 which, in turn, is fitted between the shoulder 22 and the innermost end of the tip 23.
  • the upper ends of the collet half shells 4 are joined together by means of an end closure cap 11 which extends over the radially reduced portions 19 of those half shells and which is simply in frictional engagement therewith in order to maintain the upper part of the collet member in assembled relation.
  • the conically flared lower end portion of the collet member extends through a clamping ring 28 and is maintained in engagement with that clamping ring normally by the bias of the spring 10.
  • the tip end 23 of the pencil is further provided with a shoulder 32 which is spaced downwardly from the normal spring biased position of the end of the collet member in order to provide a stop for the collet member.
  • the upper end of the collet member is depressed to move the collet member against the bias of the spring until the lower end of the collet member engages the stop 32 and at such time the conically flared lower end portion of the collet member moves out of engagement with the clamping ring 28 and the collet jaws spread in order to release their grip on the lead 17.
  • a first collet half shell is placed into the tubular bore 2 of the housing 1 so that it is in a position somewhat further extended from the housing as is illustrated in FIG. 1 with the necked portion of the collethalf shell disposed at the annulus 5b and the second collet half shell can then be placed down through the tubular opening 2 from the top, and the spring and slotted supporting ring can thereafter be fitted over these two parts.
  • the first collet half shell is disposed with its necked down portion at the annulus 5b, there will be sufficient space at the annulus to permit movement of the concially flared portion of the second collet half shell to move past the annulus.
  • the spring and slotted supporting ring can then be placed over the collar 8 and the spring compression can then be released in order to return the two collet half shells to the position illustrated in FIG. 1.
  • the end closure cap 11 can be placed over the upper end portions of the two collet half shells.
  • each individual part has a certain elasticity which makes it possible to pass a part of a larger diameter through a bore whereby either the bore itself, the collet parts, or both parts change their shape elastically for a short period of time while the parts'are assembled.
  • a mechanical pencil comprising elongated housing means having an axial bore; lead guide and collect means extending longitudinally through said axial bore and being guided therein for'movement in longitudinal direction between a lead clamping and a lead releasing position, said lead guide and collet means consisting of two elongated mirror-symmetrically arranged half shells of thermoplastic material having first inner planar faces abutting against each other and second inner planar faces set back with respect to said first planar faces and separated by a gap, said second planar faces being joined to one end of said first faces by a shoulder, said planar faces having each a central longitudinally extending groove of substantially semi-cylindrical configuration for guiding the lead in longitudinal direction and each of said grooves having at the other end of the half shells a free edge, said half shells having in the region of said second planar faces outwardly flaring portions forming together a substantially conical end portion; annular means in said housing means having an inner surface smaller than the maximum diameter of said conical end portion and arranged for cooperation therewith
  • a mechanical pencil as defined in claim 1 wherein the interior of said shells define a lead passage slightly larger in diameter than a lead to be contained therein and wherein a radially reduced portion of said shells is provided which is of a diameter substantially equal to the diameter of the lead to grip the lead extending therethrough.
  • said biasing means comprises a coil compression spring in said large diameter portion of said bore about said half shells and abutting with one end against the shoulder formed at the junction of the small and large diameter bore portions, and including abutment means on said half shells against which the other end of said coil spring abuts.
  • annular means comprises a clamping ring of resiliently deformable plastic material fixedly mounted in said housing means.
  • a mechanical pencil as defined in claim 8 and including elastic ribs in said stepped bore of said tip adjacent the small diameter end portion of said stepped bore and arranged to frictionally engage the lead extending therethrough.

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  • Mechanical Pencils And Projecting And Retracting Systems Therefor, And Multi-System Writing Instruments (AREA)
US423476A 1972-12-08 1973-12-10 Mechanical pencil Expired - Lifetime US3922098A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US05/592,252 US3998558A (en) 1972-12-08 1975-07-01 Mechanical pencil

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE2260065A DE2260065C3 (de) 1972-12-08 1972-12-08 Fallminenstift mit verschiebbarer Mine

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US05/592,252 Division US3998558A (en) 1972-12-08 1975-07-01 Mechanical pencil

Publications (1)

Publication Number Publication Date
US3922098A true US3922098A (en) 1975-11-25

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Family Applications (1)

Application Number Title Priority Date Filing Date
US423476A Expired - Lifetime US3922098A (en) 1972-12-08 1973-12-10 Mechanical pencil

Country Status (4)

Country Link
US (1) US3922098A (de)
AT (1) AT344541B (de)
CA (1) CA1001117A (de)
DE (1) DE2260065C3 (de)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4153379A (en) * 1977-01-25 1979-05-08 Chao Wen Kuei Knock-out type automatic pencil
US4230413A (en) * 1976-10-29 1980-10-28 J. S. Staedtler Mechanical pencil having collet guide
US4251163A (en) * 1979-03-21 1981-02-17 Chao Wen Kuei Knock-out type automatic pencil
US4844639A (en) * 1987-10-21 1989-07-04 Chao Wen Kwei Push-type writing instrument
US20050276554A1 (en) * 2004-06-12 2005-12-15 Hubertus Russert Apparatus and method for producing an end of an optical fiber bundle and improved optical fiber bundle made with same

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5159642U (de) * 1974-11-01 1976-05-11
JPS51152438U (de) * 1975-05-30 1976-12-06
DE3125441C2 (de) * 1981-06-27 1983-07-07 Fa. A.W. Faber-Castell, 8504 Stein Füllminenstift mit automatischem Minenvorschub und Nachschub der Folgemine
DE3207923C2 (de) * 1982-03-05 1984-05-17 Fa. A.W. Faber-Castell, 8504 Stein Feinminenstift mit durch den Schreibdruck bewirktem automatischem Vorschub der Mine
ES2066100T3 (es) * 1986-10-30 1995-03-01 Kotobuki & Co Ltd Boquilla portaminas de un lapiz mecanico.
DE3906346A1 (de) * 1989-03-01 1990-09-06 Staedtler Fa J S Klemmzange fuer fuellminenstifte

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US654722A (en) * 1899-02-27 1900-07-31 William Hughes Francis Holder for pencil leads, crayons, leads, & c.
US2353177A (en) * 1942-09-17 1944-07-11 Eversharp Inc Mechanical pencil
US2473149A (en) * 1945-09-07 1949-06-14 American Lead Pencil Co Mechanical pencil with step-by-steplead feeding means

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US654722A (en) * 1899-02-27 1900-07-31 William Hughes Francis Holder for pencil leads, crayons, leads, & c.
US2353177A (en) * 1942-09-17 1944-07-11 Eversharp Inc Mechanical pencil
US2473149A (en) * 1945-09-07 1949-06-14 American Lead Pencil Co Mechanical pencil with step-by-steplead feeding means

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4230413A (en) * 1976-10-29 1980-10-28 J. S. Staedtler Mechanical pencil having collet guide
US4153379A (en) * 1977-01-25 1979-05-08 Chao Wen Kuei Knock-out type automatic pencil
US4251163A (en) * 1979-03-21 1981-02-17 Chao Wen Kuei Knock-out type automatic pencil
US4844639A (en) * 1987-10-21 1989-07-04 Chao Wen Kwei Push-type writing instrument
US20050276554A1 (en) * 2004-06-12 2005-12-15 Hubertus Russert Apparatus and method for producing an end of an optical fiber bundle and improved optical fiber bundle made with same
US7457499B2 (en) 2004-06-12 2008-11-25 Schott Ag Apparatus and method for producing an end of an optical fiber bundle and improved optical fiber bundle made with same
US7958753B2 (en) 2004-06-12 2011-06-14 Schott Ag Apparatus and method for producing an end of an optical fiber bundle and improved optical fiber bundle made with same

Also Published As

Publication number Publication date
DE2260065C3 (de) 1979-07-19
ATA917573A (de) 1977-11-15
CA1001117A (en) 1976-12-07
DE2260065B2 (de) 1976-01-15
AT344541B (de) 1978-07-25
DE2260065A1 (de) 1974-06-12

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