US2082844A - Mechanical pencil - Google Patents

Description

June 8, 1937. J. MEILNER MECHANICAL PENCIL Filed March 28, 1935 Maine/ INvr-:m-on 70596 BYQQIAHQ ATTORNEYS l Patented June 8, 1937* UNITED STATES:

MECHANICAL PENCIL Joseph Meilner, West Orange, N. J., assignor to Eagle Pencil Company, a corporation of Dela- Ware Application March 28, 1935, Serial No. 13,378

Claims.

My present invention relates to mechanical pencils, more especially to that type which operates by helical or screw feed.

As c onducive to a clear understanding of the 5 invention, it is noted that in mechanical pencils of the helical feed type it has heretofore been limportant to provide an accurate and corre' s pondingly costly correlation between the slotted lead tube and the encircling helical track for the offset of the lead propeller riding in said tube.

'.For, were the fit between said track and said tube excessively tight, the need for forceful manipulation during pointadjustment would render the pencil objectionable even though the 1.3/ structure were sufilciently strong to withstand the strain. On the other hand, were the frictional grip between the lead tube and the barrel or track insumcient, the seriousdifculty would arise ,that the lead point would recede into the barrel under pressure exerted in writing.

It is among the objects of the invention to provide a pencil of the above type that with little effort is adjustable for writing, yet without the looseness that leads to the objectionable reces- 5 sion. of the point under writing pressure and this without on the one hand complicating or adding parts to the construction. or on the other hand introducing the need and expense for operating to close tolerances. y In the accompanying drawing, in which isv Y shown one of various possible embodiments of the several features of the invention:-

Fig. 1 is a view in longitudinal cross section showing the invention applied'to one desirable form of pencil, y

Fig. 2 is a fragmentary view in longitudinal cross section taken on the line 2-2 of Fig. 1, Figs.l 3 and 4 are transverse sectional views on a larger scale taken respectively on lines 3 -3 and I-l of Fig. 1,

Fig. 5 is a perspective view from one side of" the lead tube, and

Fig. 6 is a similar perspective view from the opposite side of said tube.

Referring now to the drawing, the barrel l0 is shown of molded composition, such as bakelite, vulcanite and the like with an unlined bore II having a threaded or helical track I2 molded as a unitary part thereof. Within the bore Il is 50 a metal tube I3 which extends the entire length of the pencil, and accommodates a lead propeller Il with an offset portion I5 protruding through -a longitudinal slot I6 in the tube and riding along the helical track I2. Preferably thelad 55 propeller comprises a clutch tube I4 frictionally (Cl. 1Z0-18) gripping th'e rear end of the lead I1, andan ejector rod I8 telescoped thereinto and having an offset I9 also riding along the track I2. 'lhe ejector rod advances with the clutch tube I4 but is caused to be advanced relative thereto for ejection of the lead stump after the clutch tube has reached the point extremity of the track I2.

A ferrule 20 preferably is keyed at 22 to the rear end of the tube I3 and is rotatable on the upper end of the barrel I0 to rotate the tube I3 within the barrel. Preferably an eraser carrying ferrule 2l is frctionally and removably telescoped over ferrule 20. The forward or point` end of the tube I3 extends into and preferably has a bearing in a depression 23 in the metal tip 25 from the point of which the forward end of the lead I'l protrudes. Tip 25 may be molded at its widerl end 26 into the forward end of the molded barrel structure I0.

The construction thus far briefly describedlis substantially that -of the prior patent to Chesler 1,956,271 of April 24. 1934, to which reference is made for further details, which however. are not material to the present invention. It will be understood that the improvement now to be described isA by no means limited in its applicability to the speciiic structure of the Chesler patent illustratively described, but is likewise useful in connection with barrels of metal or with barrels having distinct helical feed sleeves or liners. The invention isv also applicable in,`

relations in which the helical feed sleeve or track is rotatable with the ferrule and the slottedy lead tube' is flxed relative to the barrel.

According to the present invention the lead tube I3 may be made of a diameter slightly smaller than the bore of the barrel, so as to afford minute clearance therein. Near its upper end the lead tube is spread out to alford a resilient clutch to grip the corresponding portion of the barrel. -A desirable manner of producing this clutch correlation is shown in Figsw andV 6. where a longitudinal slit 30 is cut into the tube diametrically opposite the slot I6 and by resort to an appropriate spreading tool the bridges of metal 3| and 32 between the slit andthe slot are spread outwardly to cause the tube, slot I6 and slit 30 to be bowed as shown to a gradually widened middle or spindle shape at that local- Y ized region. In the course of insertion of tube I3 into the barrel I0, the widened spindle portion 30-32 of the tube will be somewhat contracted by the bore II of the. barrel and will thereby be caused resiliently to clutch or grip Said bore near the upper or ferrule end thereof.

and

-the bore ii or the tube i3 be not made with great accuracy, the spring clutch 30-32 aiords a dependable hold to prevent receding of the point under writing pressure. vThe split tube being substantially free from contact with the bore of the barrel substantially throughout the length thereof; there is no likelihood of the parts becoming jammed and theadjustment of the lead is readily eiected without distortion of the tube i3 since the readily yielding clutch 30-32 is near the ferrule 20 from which said tube is turned. It will thus be seen that there is herein described apparatus in which the several features of this invention are embodied, which in its action attains the various objects of the invention and is well suited to meet the requirements of practical use.

As many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made -without departing from the scope thereof, it is intended that all matter contained in the abovel description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, what I claim as new and desire to secure by Letters'Patcutis: y

1. A mechanical lead pencil comprising a barrel having'a coaxial helical feed rigid therewith,v a

' metal tube passing through said barrel and having a lead follower therein with a lateral offset protruding through a slot longitudinally of .said n tube and riding in said helical feed, a bearing for said tube near the point of said pencil, a ferrule at the opposite end of said pencil rotatable on said barrel and fixed to said tube, said tube having a portion of the continuous length thereof near'saidferrule spread outward for frictional engagement with the inner cylindrical wall of the helical feed, the length of lsaid tube between said`spread portion and said point being substantially free from frictional engagement with said helical feed.

2. A mechanical pencil comprising a barrel having a helical feed rigid and coaxial therewith, a feed tube extending longitudinally through said barrel, means xed to one end of said tube, rotatable about said barrel and serving helical feed and the slotted'tube.

ao'eaeee to rotate said feed tube, a lead propelling member within said tube having ,an oiset protruding through a slot longitudinally thereof and riding along said helical feed, said slotted tube being also slit for a short -part of the length thereof near the ferrule, the metal between the slot and the slit being spread outward to aord a friction clutch between the inner` cylindrical 3. A mechanical pencil comprising a barrel having a helical feed rigid and coaxial therewith, a feedtube extending longitudinally through said barrel, rotatable means exposed at one end of said tube and connected to and serving to rotate said feed tube', a lead propelling member within said tube having an offset protruding through a slot the length of the tube and riding along said helical feed, said slotted tube having a short -slit longitudinally thereof along the element diametrically opposite the rear portion of the slot thereof, the strips of said tube between said slit and said slot, being spread outward to afford friction clutching engagement of the tube in the helical feed, the forward end of said slotted tube having bearing engagement in the barrel near the point end thereof.

4. A mechanical pencil comprising a barrel of '-molded material having an integral helical feed track therein, a metal tube within said barrel, means -attached in driving relation to said tube,

and rotatable about the end of said barrel, said tubehaving a lead propelling member therein with a lateral 'offset protruding vthrough a slot longitudinally of said tube and riding valong said track, said 'tube `having one or more short longitudinal slits near the ferrule end thereof-in addition to said slot, with the intervening bands of metal spread outward, frictionally to clutch the inner wall of the barrel, the forward end of said tube having a bearing mount in the barrel near the point thereof, the length of said slotted tube between said clutching portion and said point being substantially free from friction engagement with respect to said barrel.

5. As an article of manufacture, a feed tube for a. mechanical lead pencil, said tube being of metal stock having a. longitudinal slot from end to endv thereof and having a short slit near the rear end thereof spaced from said longitudinal slot, the metal of said tube being spread outward between said slit and said slot for a friction clutch conformation thereat.

JOSEPH MIEILNER.

part of the

Images