US2893109A - Lead pencil - Google Patents

Description

July 7, 1959 YQUNG 2,893,109

LEAD PENCIL Filed May 18, 1956 I INVENTOR ATTORNEYS United States Patent LEAD PENCIL Marshall B. .Young, Riverdale, N.Y., assignor to Eagle Pencil Company, a corporation of Delaware Application May 18, 1956, Serial No. 585,904

7 1 Claim. (Cl. 29-90) The present invention relates to lead pencils, more especially to drafting pencils.

It is among the objects of the invention to provide a lead pencil, more particularly a drafting pencil, with an effective burnishing tool securely aflixed at its free end, simple and inexpensive in construction and attractive in appearance, for convenience of the draftsman in smoothing out the drawing paper or cloth after erasure.

In the accompanying drawings in which is shown one of various possible embodiments of the several features of the invention,

Fig. 1 is a side elevation of a lead pencil showing the invention,

Fig. 2 is a longitudinal cross-sectional view of the upper part of the pencil on a larger scale,

Fig. 3 is a transverse sectional view also on a larger scale taken on line 33 of Fig. l, and

Fig. 4 is a dropped perspective view on an enlarged scale showing the upper end of the pencil and the burnishing cap before assembly.

Referring now to the drawings, there is shown a generally conventional lead pencil, such as a draftmans pencil, which pencil comprises the lead rod and the conventional casing C, generally of wood, made of two segments 11 and 12 accommodating the lead in axial relation therebetween and glued as at 13 about the lead.

The burnishing cap H is a permanent part of the pencil casing at the rear or non-writing end thereof. That cap presents an end plate 14, preferably with a rounded face 15, desirably in the form of the segment of a sphere of relatively large diameter, and having a smooth polished surface for suitability in burnishing.

Permanently and securely to attach the burnishing cap to the pencil as a substantially integral part thereof not likely to be removed therefrom, especially under the stress of burnishing operation, the cap is desirably not merely cemented to the lead pencil, but keyed thereto in relation that will resist any shearing thrust.

A preferred keying connection of the cap, which preferably is a plate registering exactly with the end face of the pencil, consists of a plurality of prongs 16 integral with the cap, uniformly spaced about the cap and extending at right angles from the inner face 17 of the cap. The prongs 16 are to be accommodated in corresponding notches 18 in the end of the pencil casing; notches of length, width, depth and shape generally, that is complementary to the respective prongs 16, snugly to accommodate the same, so that the outer face of each prong extends flush with the surface of the pencil.

Ordinarily the lead pencil casing is hexagonal in form and thus has six panels, generally of equal width. For use with such casing, the burnishing cap preferably has three prongs extending at right angles to and integral with alternate sides of the correspondingly hexagonal burnishing face 14 of the burnishing cap. Desirably each prong is triangular in cross section and has a relatively thick root 16 integral with the inner face 17 of the cap and ex tending from the corresponding one of its six sides, the

face of each prong at such root being preferably of width substantially equal to the length of such side.

The end portion 14 of the cap is desirably A1" to Mt" thick. Each prong desirably tapers in width and in thickness to a relatively sharp point 19 at its free end. Desirably, each prong is of length of about A" to The maximum thickness of each prong at its root may be approximately A" to By this construction the burnishing cap with its integral prongs is sufficiently strong and rugged to withstand the strain to which it is subjected in burnishing operation.

In the hexagonal pencil casing the notches 18 are in alternate panels, each notch being of length, width, depth and shape matching substantially exactly those of the prong 16 that it is to accommodate. In practice, with the thickness of prong at its root as above described, the deepest part of each notch is in the lead pencil, that is, the part at the very extremity of the lead pencil, nearly reaches the very extremity of the length of lead rod 10, while the major portion of each notch, which progressively becomes shallower from the end of the lead pencil to the extremity of the notch is spaced by intervening wood of the casing from the corresponding length of the lead rod.

By the arrangement set forth, the burnishing cap construction extends at its sides flush with the ends of the panels, the prongs on the cap substantially fill the notches and the faces of the prongs extend flush with the notched panels in which such prongs are accommodated.

The burnishing cap as set forth is desirably cemented in place, the cement covering the entire inner face of the burnishing cap and the entire surface other than the exposed face of the prongs so that an effective bond is obtained with respect to the relatively porous end of the wooden casing and the correspondingly porous faces of the notches in said casing. Desirably sufficient clearance exists between the prongs and the corresponding notches to accommodate the intervening cement.

While the cap with its integral key construction, preferably prongs as described, could be made of metal, it is preferably made of thermosetting relatively non-hygroscopic plastic, of suflicient hardness for its intended purpose. Polystyrene has been found in practice to be especially suitable for the purpose and has the further advantage that it lends itself to fabrication in pure white or any other desired color. The burnishing cap with its integral prongs is desirably molded, as for instance by injection molding and in such molding the inner face of the cap desirably is formed with a central depression 20 to register with the end of the lead rod for cement bonding at this point also.

While, as above noted, the invention has its preferred application to a. drafting pencil, it will be understood that it could be applied, if desired, to a lead holder or to other suitable shaft or rod, useful as a handle for a burnishing tool for use in drafting and kindred operations.

As many changes could be made in the above article, and many apparently widely different embodiments of this invention could be made without departing from the scope of the claim, it is intended that all matter contained in the above description or shown in the accompanying drawings 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 Patent of the United States is:

An implement comprising a rod shaped handle member of wood which is hexagonal in cross section and thus has six panels, a burnishing cap at one end thereof of polystyrene, said cap being hexagonal in end view and of dimensions completely to cover the end of the handle and having a keying structure integral therewith consist- Patented July 7, 1959.

2,893,109 3 a ing of three prongs triangular in cross section with the References Cited in the file of this patent roots thereof flush With the periphery ofthe cap, said prongs tapering toward a substantially pointed free end UNITED STATES PATENTS bothrin-their. width and their triangular cross section, said- 73,883 Faber Jan. 28, 1868 prongs being three in number, extending ,from alternate 5 204,421 Chamberlain June 4, 1878 sides of the hexagonal cap and of'width at their roots 509,899 Heysinger Dec. 5, 1893 substantially equal to the widths of alternate panels, 545,375 Olds Aug. 27, 1895 said handle having notches at alternate panels thereof 7 761,428 Tucker May 31, 1904 extending inward and downward from its free end and'ol 305,477 Mcllvin June 3, 1919 dimensions complementary, to those of the respective 10 1,333,644 Torey Mar'.16,'1920 prongs on the burnishing cap for accommodating said 1,531,983 SaWyert. Mar. 31, 1925 prongs to extend'flush with the corresponding faces of 1,805,279 Floyd May 12, 1931 the panels, said burnishing cap being adhesively attached 2,312,069 Baumgartner Feb.-23., 1943 to the handle substantially throughout that area of the 2,482,273 Harris Sept. 20, 1949 cap and prongs which engage the handle member. 15

Images