US1573055A - Mechanical pencil - Google Patents

Description

Feb. 16,1926. 1,573,055

B. B. GOLDSMITH MECHANICAL PENCIL Filed May 21, 1921 Patented Feb. 16, 1926.

BYRON B. GoLnsMrrH.

or new YORK, N. Y.

MECHANICAL "r'nnoIL.

Application filed May 21,

To all 207mm 2'25 may concern: I

Be it known that I, BYRON B. GoLnsMiTH, a citizen of the United States, residing in New York, county and State of New York, have invented a certain Improvement in liiechanical Pencils, of which the following a specification.

The present invention has reference to a simple, inexpensive and effective form of mechanical pencil of the kind in which a removable lead is inserted in a suitable holder from which it may be gradually protruded to any extent desired by suitable mechanism.

In this improved pencil the lead is inserted into a lead tube which fits it closely so as to support it properly during use, the

' outer tip of said tube being constructed to exert a proper resilient pressure upon the lead. The wall of the tube at its inner or rear end is cut through in a spiral, and a pusher for the lead fits within the tube, being provided with a portion which projects outward througl'i said spiral cut. An outer casing encloses the inner end of the lead tube and is provided with means constantly in engagement with the projecting portion'of the pusher, so that it can be made to revolve and travel forward along the spiral in the lead tube by causing the casing to turn upon said tube.

This improvement lends itself especially to cheap construction, while providing a thoroughly practical and reliable pencil.

A preferred embodiment of the invention is illustrated in the accompanying drawings wherein Figure 1 is a side elevation of a complete pencil, Figure 2 is a longitudinal sectional view out a part of the same, and Figure 3 is a cross-sectional view on the plane 33 in Figure 2.

The lead tube (shown partly in section and partly in elevation in Figure 2) has a forward or outer portion 10 preferably tapered and split as shown in order to grip the lead 11 closely, in the usual manner.

The inner portion of the tube is enclosed by the casing 12, and has a continuous spiral slot 13 formed in its walls.

Fitting snugly within the spirally out portion of the tube 10 is a. thin rod or pusher 14 provided with a projection passing through the spiral opening 13. This pro- 1921. Serial No. 471,319.

jection is preferably formed, as shown, by simply bending the inner extremity of the pusher rod at right angles, as at 15.

The casing 12 has a straight longitudinal slot within it which receives the tip of the projection 15; This is preferably provided, in the manner illustrated, by inserting within the casing 2 a tightly fitting quasi-tubular lining 16, the ends of which are slightly spaced apart to form the desired slot, as shown clearly in Figure 3. p

In order togive the pencil a better appearance, a tapered masking shell 17 is provided, which tightly covers the forward opening of the casing. The forward edge of this shell s turned in and enters a circular notch in the lead tube, permitting the shell to turn on the tube when the casing is revolved, while preventing the tube from coming out of the casing.

From the above it will be clear that the lead may be advanced by grasping the front of the lead tube with one hand and the casing with the other, and imparting a relative rotation to them. Relative rotation in one direction will advance the lead and the opposite rotation will leave the lead free to be pushed inward. v

Of course it is within the scope of this invention to have a separate spiral fixed to the lead tube instead of having it made of one piece. The construction shown can also be used in that class of pencils whichis operated from the back of the pencil instead of from the front. All that isn-ecessary is to have the casing 12 hollow throughout its length and to have either the lead tube extend all the way back or to have the tube 16 do s0. 7

The one which extends back must be made to revolve and the other one fixed, the-basic principle being simply that one must revolve with respect to the other. i

hat I claim is 1. A mechanical pencil comprising an external casing having a central cylindrical cavity open at theforward end and closed at the rear and having a longitudinal internal channel, a lead tube having a cylindrical surface fitting within said cylindrical cavity and projecting out of the forward end of said cavity to permit it to be grasped in Inc operation, said lead tube having a spiral slot through it a lead snugly fitting for all its length in said lead tube, and a pusher rod fitting said lead tube and having a portion extending through the spiral slot and into the longitudinal channel in said casing.

2. A pencil as in claim 1 in combination with a tapered shell fitting tightly over the forward end of the casing and a resilient 10 inturned rim adapted to spring into an annular channel near the outer end of the lead tube. I

3. A pencil as in claim 1 wherein the easingcomprises an outer portion and a cylindrically disposed bent metallic lining Whose nearlymeeting edges provide the longitudinal channel of the casing.

In testimony whereof I have hereto set my hand on this 20th day of May, 1921.

BYRON B. GOLDSMITH.

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