US2750924A - Lead pencils - Google Patents

Description

June 19, 1956 KNIGHT 2,750,924

LEAD PENCILS Filed March 17, 1952 if 4 z 4 6 W. 4..

5a 5 5c 5d 2 United States Patent LEAD PENCILS Hugh T. Knight, Montrosc, Victoria, Australia Application March 17, 1952, Serial No. 277,020

3 Claims. (Cl. 120-49) This invention relates to lead pencils, and refers more particularly to the class of lead pencils, in which a longitudinally adjusted lead, contained in a suitably slotted casing can be operated for use as a writing instrument. The improvements in the particular class described are as follows: i

(a) A lead pencil having a non-permanent non-refillable casing which eliminates the need to insert refill leads into the casing.

(b) A lead pencil in which a lead adjusting and clamping device is detachable and transferable.

(c) A lead pencil having a combined lead adjusting and clamping device.

(d) A lead pencil in which the lead is either concentric or eccentric in its casing.

(e) A lead pencil having an integral wooden casing in which a slot extends the full length of the pencil.

The object of my invention is to provide a replacement lead pencil, for either general or special use, having an adjustable lead in an expendable casing, which embodies the improvements in the class described, and costing approximately the same as an ordinary lead pencil having a fixed lead.

The basic idea of my invention is to provide a lead pencil of the class described in which the casing or body containing the lead is of no further use when the lead it contained when it was new is exhausted due to wear, in combination with a lead adjusting and clamping device which can be repeatedly transferred to new replacement pencils, containing new leads.

This improvement in lead pencils has never been described or claimed in any previous specification relating to lead pencils with an adjustable lead.

The necessity of having to insert refill leads into the pencil casing, has always been a disadvantage in mechanical pencils of all descriptions, especially a long lead which is most suitable in this class of pencil.

In my improved pencil, the lead is the correct size in the pencil and is ready for use as a replacement after the operating device is transferred to the new pencil.

The combined lead adjusting and clamping device is located on the body of the pencil, and is not in direct contact with the tapered writing end of the pencil where the pressure on the lead when the pencil is in use has a tendency to break the lead in the casing. The combined lead adjusting and clamping device as described herein, adjusts and clamps the lead at different positions in the casing when required, and it can quickly be operated to release, adjust and clamp the lead without diificulty.

This improvement is effected by a threaded and split spring steel sleeve, which is in a sliding fit on the casing and has a tendency to open when released from a complementary threaded nut on the sleeve. The clamp actually controls the friction between the sleeve, the lead and the casing, and eliminates the diiliculty of adjusting the lead against the friction required to hold the lead in position when in use. The clamp when tightened is also a back stop for the lead independently of any actual clamping effect on the lead itself.

A further improvement in my invention, is a lead pencil of the class described, in which the lead core is located in a position out of centre, or eccentric to the longitudinal axis of the casing.

A chisel pointed lead pencil of this description not only provides a long adjustment for the lead, but gives a closer and more accurate alignment to the work when used by draftsmen.

The improvement directly concerned with the casing of the pencil provides for a longitudinal slot extending the full length of the pencil, which makes it possible for a wooden pencil to be made in one piece instead of two half sections cemented together. Solid wood is a suitable material for the casing, although a compo sition moulded material such as wood pulp or the like formed ready to receive the lead should be satisfactory.

The use of solid round wood in the manufacture of the casing reduces the cost of production.

Multiple dowel lengths cut direct from timber and slotted by a circular saw in the same operation are then drawn through a broach roughly shaped similar to a hacksaw blade with the teeth set and shaped to undercut the core chamber.

This process necessitates that the slot must be cut the full length of the pencil, and for this reason a ferrule which can be cemented to the writing end is required.

Having now defined the objects and improvements of my invention and in order to make the details fully understood, I will now describe it with reference to the accompanying drawings in which like reference characters designate the parts in all the views.

Fig. l is a side elevation and part section of my improved lead pencil.

Fig. 2 is a side elevation and part section at right angles to Fig. l of a modified form of the pencil shown, with the lead retracted and the operating device including the taper ferrule at the writing end removed.

Fig. 3 is an enlarged side view of the lead adjusting and clamping device.

Fig. 4 is an enlarged end view of the lead adjusting and clamping device at right angles to Fig. 3.

The pencil body or casing 1 consists of a pencil shaped body, having a tapered writing end similar to an ordinary wooden lead pencil having the writing end sharpened ready for use.

A lead stick 2 is in a sliding fit and is adjustable longitudinally in a lead containing chamber 3.

The pencil shown in Fig. 1 has the lead 2 located eccentric to the longitudinal axis.

The pencil shown in Fig. 2 has the'lead located in the centre in the conventional manner. Both types of pencils have a lead adjusting slot 4 or 4, respectively, extending the full length of the pencil on one side of the casing 1 or 1', respectively.

The slot 4 or 4, respectively, which is smaller in width than the diameter of the lead 2 or 2', respectively, is cut radially from the outside of the casing into the chamber 3 or 3', respectively, although for manufacturing purposes and to give the casing greater resiliency, it may extend past the core chamber.

The combined lead adjusting and lead clamping device 5 which is retained by friction to the external surface of the pencil casing, is adjustable in itself and also adjustable longitudinally in the casing. It is provided to adjust and clamp the lead 2 to compensate for wear or breakage of the lead when the pencil is in use.

The small tapered ferrule 6, Fig. 1, strengthens the tapered writing end of the pencil and also prevents the casing of the pencil from being mutilated when the projecting lead is sharpened by a knife or the like.

The diameter of the lead most suitable for the pencil is the same as used in an ordinary wooden pencil.

The correct sharpening device for the pencil is a point sharpener.

Figs. 3 and 4 illustrate the construction of the lead adjusting and clamping device.

The spring steel sleeve 5a which has a tendency to open, has a tapered thread 5b formed in its circumferonce, which engages with a complementary threaded tapered nut 50 on the sleeve 5a.

A pin 5d fixed to the sleeve 5a extends radially inwards into the slot 4 of the casing 1.

The sleeve 5a has in it a longitudinal opening 5e which allows for the opening and closing of the sleeve when in use.

The outwardly directed projection 5f integral with the sleeve is provided to prevent the pencil from rolling out of place when at rest.

To operate and adjust the lead in the casing the nut 5b is unscrewed about half a revolution thereby rcleasing the clamping contact between the sleeve, the casing and the lead, which allows the lead to be adjusted by means of the pin 5d which is in contact with the end of the lead opposite the writing end.

The released adjusting device is then moved by the finger and thumb towards the writing end of the pencil thereby projecting the lead from the pencil to the required distance. The clamping nut is then tightened on the sleeve and the pencil is ready for use.

When the lead is almost completely used the pin 5d will come into contact with the ferrule 6. The casing then is of no further use and the lead adjusting and clamping device is removed by way of the opposite end to the writing end, and transferred to a new replacement casing containing a new lead.

With regard to the improvement in which the lead in the pencil is located in an eccentric position in the casing, it is obvious that this improvement could also be applied to solid wooden lead pencils having fixed leads.

Throughout this specification, and in the following claims, I have referred to lead as the marking element, but it is to be understood that other marking stylus can be used, without altering the meaning of the specification or claims.

This specification describes an example of my invention which may be improved or altered within the meaning of the following claims.

What is claimed is:

1. In a propelling lead pencil, the combination of a lead-containing pencil body and a detachable lead-propelling and lead-clamping device adjustably attached to the lead-containing pencil body, said pencil body being tapered at the writing end and longitudinally slotted ra dially, the slot communicating within the pencil body with a longitudinal enlarged lead-accommodating chamber, and said detachable lead-propelling and lead-clamping device consisting of a taper-threaded spring-steel split sleeve having a tendency to part and fitted with a complementary threaded locking nut and with a lead-propelling pin projecting through said slot into said leadaccommodating chamber.

2- A pencil in accordance with claim 1, said leadaccommodating chamber being eccentric of the pencil body.

3. In a propelling lead-pencil, the combination of a lead-containing pencil body and a detachable lead-propelling and lead-clamping device adjustably attached to the lead-containing pencil body, said pencil body being tapered at the writing end and longitudinally slotted radially, the slot communicating within the pencil body with a longitudinal enlarged lead accommodating chamber located eccentrically of the pencil body and said detachable lead-propelling and lead-clamping device consisting of a taper-threaded spring-steel split sleeve having a tendency to part and fitted with a complementary threaded locking nut, a lead-propelling pin fixed to said sleeve and projecting from said sleeve through said slot into said lead-accommodating chamber and a detent member or stop projecting outwardly from said sleeve.

References Cited in the file of this patent UNITED STATES PATENTS 444,974 Climenson Jan. 20, 1891 763,429 Von Schemnitzky June 28, 1904 1,307,159 Steelreath June 17, 1919 2,463,345 Youngquist Mar. 1, 1949 FOREIGN PATENTS 227,352 Great Britain Jan. .15, 1925 549,180 Germany Apr. 23, 1932 597,296 Germany May 23, 1934 525,287 Great Britain Aug. 26, 1940

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