US1353345A - Mechanical pencil - Google Patents

Description

M. M. KAUFMAN-N AND 1. P. LYNN.

MECHANAICAL PENCIL. APPLICATION FlLED FEB.II. 1920.

Pandsept. 21,1920'.

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MCHAEL lVI. KAUFMANN ANB JOHN l?. L'YTN, F CHGAGO, ILLNOS, ASSEGNORE T0 PHLIP P. THOMAS, TRUSTEE, 0F MINNEAPOLIS, MINNESOTA. i

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Specification of Letters Patent.

Patented Sept. 2i, i92ti.

Application filed February 11, 1920. Serial No. 358,005.

T 0 allwiwm it may concern:

Be it known that We, MICHAEL M. KAUF- MANN and JOHN P. LYNN, residing at Chicago, in the county of Cookand State of Illinois, have invented certain new and useful Improvements in Mechanical Pencils; and We do hereby vdeclare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the ait to which it appertains to maire and use the same.

This inventionrelates to a mechanical pencil, and has for its object to provide a simple, neat and efficient device of' this character which can be readily constructed Without the use of special machinery and equipment, and which has very 'few and simple parts.

The invention consists in the features of construction and combinations of parts hereinafterv fully described and particularly claimed.

In the accompanying drawings illustrating a suitable embodiment of 'the invention:

Figure -1 is a central longitudinal section of a pencil constructed in accordance with the invention a part of the tip and cylindrical portion of the barrel being brolren away. Q'

Figs. -2- and -3- are respectively transverse sections on an enlarged scale on lthe lines 2-2 and 3 3 of Fig. 1.

The said pencil comprises the barrel 1 terminating at one end in the tapered tip portion 2, the extreme end of which is longitudinally slotted to render it expansible. This extreme end has a bore Which is normally of slightly less diameter than the leads adapted to be projected therethrough and is adapted to be slightly expanded when leads are forced therethrough by the projecting means hereinafter described.

Mounted concentrically vWithin the barrel -1 is a lead tube 4 which is suitably held in place therein and extends from a point Within the tapered tip portion of the barrel inwardly of the expansible end thereof to the other open end of said barrel 1. This tube has an inner diameter slightly larger than that of the leads adapted to be received therein, and is disposed in axial alinement With the bore in the tip through which the leads are to be projected. I

The barrel is internally threaded, as at 5, in its cylindrical end portion for engaging the lead projecting mechanism. The latter comprises the cap member consisting of an outer sleeve or tube 6 which is adapted to telescopically receive the open Aend portion of Vthe barrel and is provided in its extreme op? therewitlfiv there is mounted an externally threaded tube 11 terminating at one end inA an annular edge iiange 12 having an outer annular edge which snugly' fits the bore of the tube 6 and is soldered or otherwise rigi idly secured therein. flange is preferably integral with a central portion or plug 1S. Secured in the central portion 01 said plug 13 .and extending downwardly to a point contiguous to the inner end of the tube 6 is a small tube 14 having a bore suiiiciently large to telescopically receive the lead tube 4. One end portion of the tube it is slightly annularly reduced as at 14a to lit the central npening in the plug member 12 and is rendered rigid With the latter. Extending centrally of said tube lei. is the rod or plunger 15 which projects 'rom the mouth thereof, and Which is also slightly annularly reduced at its other end portion as -at 15a to fit the contracted bore of the portion 14a of said tube 14 and is made rigid With the latter.

The annular space 17 between the tube` The said annular out of same and into the barrel l, when the ,pencil is in use, by means of a suitable removable cap l5. The closure cap 16 is provided with lugs or projections 18 for digitally engaging said cap.

The leads adapted to be used in the pencil may be of any desired length Within certain limits. Assuming, for example, that the-barrel l is about four inches long, it

I 'ed tube 11 With the threads of the barrel l.

the irst of the two leads in the lead tube 4 Will be projected to extend about one-eighth of an inch from the tip 2. rfhus as soon as one lead has been completely exhausted, the next lead will be engaged Within the slotted portion of the tip 2, but will not project therefrom and thereupon it will be neces- Sary to reversely rotate the cap member to, remove the same from the barrel l and drop another leadiinto the lead tube It, and thereupon replace the cap member.

i The threads are preferably of such pitch as Will not require a' great many revolutions-otl the cap member relatively to the barrel to remove said cap from the latter for the purpose of inserting new leads, it being only necessary that such threads shall not be of so steep a pitch as to cause reverse rotation of the parts by the pressure exertedk by the lead during the operation of Writing. lt will be noted that Ween the cap is removed from the barrel there is no` mechanism visible except the projecting end of the plunger l5 and the cap 16 for 'the magazine, since the threads of the externally threaded tube ll are not exposed to view.

The longitudinal slots 7 in the outer end portion of the tube (S also permit the insertion-of a pin, or similar sharp instrument, into said slots for the purpose of engaging and removing a Worn-down eraser from the outer end of the tube 6 for the purpose of said barrel and extending from a point Within the tapered tip portion thereof to the open end of the same, a cap member for said barrel comprising a sleeve adapted to telescopically receive the open end of the barrel, an externally threaded tube rigid and concentric with said sleeve and extending from the outer end portion to substantially the mouth thereof, the cylindrical portion ot the barrel being internally threaded to engage said externally threaded tube oiisaid ca p member, a lead projecting plunger rigid with and mounted axially of the ca p member and projecting from the inner end thereof and adapted to enter the inner end portion oi the lead tube for effecting projection ot leads from the barrel as said ca p member is rotated relatively to said barrel in one direction.

2. A mechanical pencil comprising a barrel open at one end and terminating at its other end in a 'tapered tip, adapted for resisting the passage of leadsl from said barrel, a lead tube mounted concentrically within said barrel and extending from a point Within the tapered tip portion `thereof to thc open end of the same, a cap member `for said barrel comprising a sleeve adapted to tclescopically receive the open cud oi the barrel, an externally threaded tube rigid and concentric with said sleeve and extending from the outer end portion to substantially tho mouth thereof, the cylindrical portion ot the barrel being internally threaded to engage said externally threaded tube ot said cap member, a. lead projecting plunger/rigid with and mounted axially oi' the cap member and projecting from the inner end thereof and adapted to enter the inner end portion of the lead tube tor etlccting projection ot leads Jfrom the barrel as said cap member is rotated relatively to said barrel in one direction, said externally threaded tube substantially corresponding in length with that of the leads adapted to be projected from said barrel and adapted to ei'fect a shortening of the pencil a length substantially equal to the length ot one oisaid leads during projection oi the latter from said barrel throughout the length oi said lead.

3. mechanical pencil comprising a barrel open at one end and terminating at its other end in a tapered tip, adapted for resisting the passage of leads 'trom said barrel,

Aing from the outer end portion to 'substantially the mouth thereot, the cylindrical portion of the barrel being internally threaded to engage said externally threaded tube of said rap member, a lead projecting plunger rigid with and mounted axially oi' the cap meml/or and projeeling' from the inner end thereof and adapted to enter the inner end portion oi the lead tube for etici-ting projeition oi leads from the barrel as said cap member is rotated relativel)rv to said barrel in one direi'tion, a tube conventi-ie and rigid with said sleeve and plunger adapted to telesropirallv rereive the lead tube and termimating at its free end substantially at the .mouth of the externally threaded tube, the annular space between the lat-ter and said inner tube of said eap member constituting a magazine tor leads corresponding in length substantially with the leads adepted to be projected from the pencil, and a closure rap for said magazine adapted to be removably engaged with one of said inner tubes of Said cap member.

MICHAEL M. KAUFMANN. JOHN l). LYNN.

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