US3097628A - Mechanical pencil - Google Patents

Description

July 16, 1963- F. J. STOEBERL MECHANICAL PENCIL Filed July 7. 1960 United States Patent 3,097,628 MECHANICAL PENCIL Frank J. Stoeberl, Chicago, Ill., assignor to Dur-O-Lite Pencil Company, Melrose Park, Ill., .a corporation of Delaware Filed July 7, 1960, Sax-.No. 41,372 2 Claims. (Cl. 120-18) The invention relates to pencils and has reference in particular to a mechanical pencil, the body portion of which is formed of wood and wherein the tapering tip and the mechanical means for propelling the lead 131B formed of metal.

Wood pencils of the mechanical type are relatively cheap to manufacture and they are preferred by many due in part to the economy in their use, the :fact that they are longer than the conventional mechanical pencil and also because they are relatively light in weight. However, certain factors which arise in the course of their manufacture have resulted in an unsatisfactory product. One of these manufacturing problems concerns the metal tip and its effective attachment to the formed lower end of the wood body portion. In this respect the improvements of the invention attain two desirable advantages. The tip is formed irom a metal blank so that the desired economy in manufacturing is still obtained and the split metal tip thus formed is snapped onto the preformed end of the-wood pencil and the same is maintained in attached relation by'the inherent resiliency of the metal tip.

Other advantages and objectives of the invention are to provide a wood pencil of the non-magazine type having one length of lead propelled by mechanical means so that the pencil can be discarded when the lead is completely used; to provide a mechanical pencil which will simulate the common wood lead pencil in length, weight and appearance; and to provide a wood pencil as described wherein the metal tip is frictionally held while permitting rotation thereof for actuating the propelling means for the lead.

Another object of the invention is the provide a metal tip for the wood body portion of a mechanical pencil which is operatively held on the preformed end of the wood body portion by the resiliency of the tip and which also functions to apply a frictional gripping action to the lead adjacent the point protruding from the said tip.

With these and various other objects in view, the invention may consist of certain novel features of construction and operation, as will be more fully described and particularly pointed out in the specification, drawings and claims appended thereto.

In the drawings which illustrate an embodiment of the device and wherein like reference characters are used to designate like parts- FIGURE 1 is an elevational view of the wood pencil of the invention showing the metal tip in position to be attached thereto;

FIGURE 2 is a vertical sectional view taken substantially through the center of the pencil and illustrating the constructional features of the lead propelling mechanism and the metal tip;

FIGURE 3 is a transverse sectional view taken on line 33 of FIGURE 2;

FIGURE 4 is a transverse sectional view taken along line 4-4 of FIGURE 2;

FIGURE 5 is a transverse sectional view taken along line 55 of FIGURE 2; and

FIGURE 6 is a view showing the metal blank from which the tip is formed.

In the drawings the invention is illustrated in connection with a non-magazine type of pencil 10 having a ice body portion 11 formediof wood, although other material such as hard rubber, plastic and fiber may be used. The body portion 11 is provided with a central bore 12 extending axially tor the length or the body portion. A lateral groove 13 extends along one side of the central bore and communicates therewith for its entire length. The upper end of the wood body portion is provided with the usual eraser 14 and the lower end is formed at 15 into the tapering shape as shown in FIGURE 1. The said shape provides the tapering end 16, the annular groove 17, and the cylindrical portion 18 which issomewhat reduced in diameter as compared to that of the body portion 11.

The size of ,tip 20 in regards to its diameter, length and taper is not particularly critical to the invention, since the tip is expandable being formed from the blank 21 as shown in FIGURE '6. The material of the blank may be metal, plastic or other material having some resiliency. Therefore, in accordance with the invention the tip has inherent resiliency in a transverse direction which permits the tip to expand circumferentially. Normal variations in the wood or other material of the body portion will produce wide variations in the diameter of the taper 15 irrespective of the forming operation that may be employed in producing the taper. Therefore, were it not for the resiliency which is built into the metal tip 20, the end 15 would have to be formed to exact dimensions, within one or two thousandths of an inch, to properly fit within a conical tip such as may be formed a tube and which in turn would thus have exact dimensions.

The ability of the present tip to expand in a transverse direction whereby to enlarge its diameter is additionally employed to frictionally grip the lead 22 adject the point which protrudes from the metal tip. By frictionally gripping the protruding point of the lead, the same is held in place within the pencil and is prevented from inadvertently dropping out when the pencil is held vertically. The said lead is propelled by mechanism best shown in FIGURE 2 and which will now be described.

The said propelling mechanism for the lead 22 is of the conventional type consisting essentially of the spiral member 24 located within and extending for the entire length of the central bore 12. By means of the punches 25 the spiral member at its extreme lower end is secured to the tip 20 at the intermediate cylindrical portions 26 of the tip. The lead is disposed axially of the spiral member and the same protrudes from the end 27 of the tip. The plunger 28 functions to propel the lead, since it is provided with a hook 30 at its upper end and which rides within the lateral groove 13. Accordingly, rotation of the tip to rotate the spiral member in the proper direction will cause the plunger to move down and propel the lead.

As previously described the metal tip 20 is stamped from the blank 21. The top cylindrical end of the formed metal tip is provided with one or more detents 32 and these are aligned with and ride within the groove 17 to thus retain the metal tip in rotative relation on the tapered end of the wood pencil. It is preferred that the diameter of the cylindrical portion 18 of the wood pencil be slightly larger than the metal tip following formation of the same and wherein the edges forming the slot 3-3 will be in substantial contact. This is desirable since the tip should be snapped into place on the tapered end 15. With the metal tip thus in place the top part containing the detents 32 will be expanded to a slight extent and thus the expansibility of the metal tip functions to hold and retain the tip on the said tapered end. Of course, the detents 32, since they ride in the groove 17, also assist in this function of holding the metal tip in place, and additionally the detents provide for rotation of the tip for rotating the spiral member in order to propel the lead from the pencil. Although the desired expansion of the metal tip may open the slit 33 in the top part thereof, this does not materially effect the extreme lower end of the tip so that this end functions effectively to frictionally grip the protruding lead point. Since the pencil is of wood it naturally follows that the taper 15 is subjected to considerable wear. However, the resiliency of the tip 20 will take up any wear and thus the tip is held to the wood pencil for the entire life of the article.

The invention is not to be limited to or by details of construction of the particular embodiment thereof illustrated by the drawings, as various other forms of the device will, of course, be apparent to those skilled in the art Without departing from the spirit of the invention or the scope of the claims.

What is claimed is:

1. ha mechanical pencil, a body portion having an approximately central longitudinally extending bore, said body portion having a section of its length at its lower terminal end reduced in diameter, a circumferential groove formed in the section of reduced diameter, a circumferentially expandable sheet metal tip in telescoped relation on the exterior of the section of reduced diameter, said metal tip having a tapering formation in the direction of its length and having a slit extending longitudinally from end to end, at least one detent formed in the metal tip adjacent its top end and which has interfitting relation with the circumferential groove, whereby the metal tip is resiliently retained on the section of reduced diameter by the expandability of the metal tip while permitting relative rotation of the metal tip, means for propelling a length of lead through the metal tip to cause the lead to project from the tapered end of the metal tip, said lead propelling means at one end having a location within the metal tip and being fixed thereto, and said lead propelling means having its other end extending into the longitudinal bore of the said body portion.

2. In a mechanical pencil, a body portion having an approximately central longitudinally extending bore, a circumferential groove formed in the body portion adjacent one terminal end thereof, a circumferentially expandable metal tip in telescoped relation on the said terminal end of the body portion, said metal tip consisting of sheet metal substantially uniform in thickness and being characterized by a slit extending longitudinally from end to end, said tip having a cylindrical portion at one end and a tapering portion at its other end, at least one detent formed in the cylindrical portion of the metal tip and which rides within the circumferential groove to assist in resiliently maintaining the tip on the said terminal end of the body portion while permitting rotation of the tip, means for propelling a length of lead through the metal tip to cause the same to project from the tapered end of the tip, said lead propelling means at one end having a location within the metal tip and being fixed to the tapered end of the same, and said lead propelling means having its other end extending into the longitudinal bore of the said body portion, said metal tip at its tapered end also having resilient contact with the projecting end of the length of lead by reason of its expandability.

References Cited in the file of this patent UNITED STATES PATENTS 527,803 McCollum Oct. 23, 1894 1,410,666 Fisher Mar. 28, 1922 1,997,424 Lynn Apr. 9, 1935

Claims (1)

1. IN A MECHANICAL PENCIL, A BODY PORTION HAVING AN APPROXIMATELY CENTRAL LONGITUDINALLY EXTENDING BORE, SAID BODY PORTION HAVING A SECTION OF ITS LENGTH AT ITS LOWER TERMINAL END REDUCED IN DIAMETER, A CIRCUMFERENTIAL GROOVE FORMED IN THE SECTION OF REDUCED DIAMETER, A CIRCUMFERENTIALLY EXPANDABLE SHEET METAL TIP IN TELESCOPED RELATION ON THE EXTERIOR OF THE SECTION OF REDUCED DIAMETER, SAID METAL TIP HAVING A TAPERING FORMATION IN THE DIRECTION OF ITS LENGTH AND HAVING A SLIT EXTENDING A LONGITUDINALLY FROM END TO END, AT LEST ONE DETENT FORMED IN THE METAL TIP ADJACENT ITS TOP END AND WHICH HAS INTERFITTING RELATION WITH THE CIRCUMFERENTIAL GROOVE, WHEREBY THE METAL TIP IS RESILIENTLY RETAINED ON THE SECTION OF REDUCED DIAMETER BY THE EXPANDABILITY OF THE METAL TIP WHILE PERMITTING RELATIVE ROTATION OF THE METAL TIP, MEANS FOR PROPELLING A LENGTH OF LEAD THROUGH THE METAL TIP TO CAUSE THE LEAD TO PROJECT FROM THE TAPERED END OF THE METAL TIP, SAID LEAD PROPELLING MEANS AT ONE END HAVING A LOCATION WITHIN THE METAL TIP AND BEING FIXED THERETO, AND SAID LEAD PROPELLING MEANS HAVING ITS OTHER END EXTENDING INTO THE LONGITUDINAL BORE OF THE SAID BODY PORTION.

Images