US1425871A - Mechanical pencil - Google Patents

Description

J. G. .LIDDELL. MECHANICAL'PENCL. APPLICATION F|LED DEc. 14. 1921.

1,425,871. Patented Aug. 15, 1922.

JOHN G. LIDDELL, OF EVERETT, MASSACHUSETTS, ASSIGNOR TO MOORE PEN COMPANY,

` OF BOSTON, MASSACHUSETTS, A CORPORATION OF MASSACH'USTTS.

MECHANICAL PENCIL.

To all L0 hom it may concern:

Be it known that I, JOHN G. LIDDELL, a citizen of the United States, residing at 193 Hancock Street, Everett, in the county of Middlesex and State of Massachusetts, have invented certain new and useful Improvements in Mechanical Pencils, of which the following is a specification.

My inventlon is a mechanical lead pencil, in which the mechanism holds and controls the lead and propels or retracts it at will and finally ejects the short stub end when the lead has been worn out.

In the drawings:

Figure 1 is a longitudinal central section of my improved pencil;

Figures 2, 3 and 4 are cross-sections on lines 2 2, 3 3 and 4-4 respectively, of Figure 1; and

Figures 5, 6, 7, 8 and 9 are details, in pers ective, of separate parts of the mechamsm.

In the specification I shall speak of the pointed writing end as the front end and the opposite end as the rear end. My pencil is provided with an outer barrel, a, pointed or tapered at the front end, b, and hollow throughout. This outer barrel serves as a support and covering for the mechanism which is mounted within, in bearings fitted within or secured to the inner side of the barrel, a. These bearings are two in number, a bearing, c,- at the forward end, secured to the inner surface of the barrel, a, and a second bearing, d, inserted into the open rear end of the barrel and in frictional engagement therewith.l This rear bearing is of tubular form for the greater part of its length and has an annular groove, d', upon its outer surface, into which the rear edge of the barrel, a, is spun to connect the parts against relative longitudinal movement while permitting rotation of the parts. tapered and carries a tubular extension, cl2, having an enlarged portion, d3. This tubular extension is split longitudinally to give capacity for yielding outwardly to wedging force and is of resilient material, preferably metal. Within the barrel and with its longitudinal axis coincident with the longitudi` nal axis of the barrel, is a hollow screw member, e, its rear end carrying an annular enlargement, e', which is wedged into the extension, d2, of bearing d, spreading that extension until the annular projection e The inner end of bearing, d, isl

Specification of Letters Patent. Papijgnted Aug, 15, 1922, Application filed December 14, 1921. Serial No. 522,250.

` passes into the enlargement d3 of the bearing -section, and preferably square, as shown.

This .carrier fits and corresponds to the angularity of the tube c', within which it may slide longitudinally, but cannot turn. The

front end gX of the carrier, g, is constrlcted and split, to receive and hold a section of lead, la, (see Figure 1). Upon the outer surface of vthe tube, g, is fast a collar, g', and between the collar g and the nut, f, is mounted a spiral spring, g2. At its rear end, beyond the nut, the tube, g, is expanded, as at g3, so that the nut cannot pass over the expanded end and a slot, g4, is formed in one side of the rear end of the tube and within the tube is mounted a wire, z', which normally extends .from the front end gX of tube g to the rear end of slot g4, through which the rear end of the wire bent at right angles to pass and engage the nut 7".

Preferably, the rearwardly projecting end of bearing, d, carries a rubber eraser, d* and is covered by an ornamental -cap d5 which slips over it.

The operation is as follows: Assuming that the parts are in the position shown in Figure 1, to propel the lead out of the writing end, b, the rear bearing, d, is rotated. Through the frictional engagement of the extension d2 with the rear end e of the screw member e, the screw will be rotated. The nut f cannot rotate, being mounted upon a tube, g, angular in cross-section, which is in turn mounted in a bearing-tube, c', angular in cross-section and fast to bearing c fixed to the barrel, a. The nut f is therefore forced forward by the rotation of screw e propelling the tube, g, through the spring g2 and collar g, until the collar reaches and abuts upon the rear end of tufie c.- The constricted front end g* of the tube g, is at this time close to the inside of the extreme end of the point b of the barrel, a. The tube g, being stopped by the engagement of collar g with tube c', continued rotation of bearing, d, will propel the nut f against the resistance of the spring g2, and with it the ejector wire, z', which is engaged with the nut. The lead carrier tube being stopped in Vits longitudinal movement, the ejector wire z', will move forward and pass through the lead-holding end, g", of tube g, ejecting any lead remaining therein. ln case the operator should continue rotation of actuating-bearing, ai, after the parts have been actuated to their limit, in either direction, the engagement of the parts @Z3 and e being merely frictional permits continued rotation without injury to the mechanism. To relill, the rotation of the bearing, d,

is reversed and the nut j thereuponv will travel rearwardly carrying with it the ejector-wire, i, until the expanded inner end, g3, of tube g is reached. The new lead la, may now be inserted in the holder g and then continued rotation of the bearing d will retract the tube g and holder g* and restore all parts to their initial position asshown in igure l.

My improved mechanical pencil is simple in construction, certain and eicient in operation, of low cost to manufacture and assemble and easy to repair. The spring connection between actuating nut f and the lead-holder tube g permits of the combination with the tube g and the nut f of the ejector, z", and the actuation of that ejector after the carrier, g, has reached the limit of its forward movement. The result is a single element that propels and retracts the lead as desired and expels the short end of lead remaining in the holder when the lead is worn out.

ll have in this specification described ltelescoping tubes, angular -in cross-section, as the non-rotatable mechanism and as the best means now known to me for accomplishing the desired results. l do not, however, intend to confine myself to this specific construction, as l am aware that the telescoping tubes might be of oval,vcorrugated, or

other non-circular cross-section or held from' 'a nut, within the hollow screw; a lead-carrying tube, non-circular in cross-section, axially supported at its rear end by the nut within the hollow screw, and supported at its front end within the hollow fixed bearing at the front en d of the barrel, the carrier tube being slotted on one side at its rear end and headed behind the nut; a collar fast on the lead-carrying tube; a spiral spring surrounding the carrier tube and interposed between the collar and the nut; an ejector wire within thecarrier tube, engaging the.,

nut through the slot in .the carrier at its rear end; all combined and operating substantially as described.

Signed at Boston, Massachusetts, this 12th day of December 1921.

Jenn e, Menara..

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