US2690736A - Mechanical pencil employing clip in assembly - Google Patents

Description

Oct. 5, 1954 c w. MUSSER MECHANICAL PENCIL EMPLOYING CLIP IN ASSEMBLY Original Filed Oct. 10, 1950 XNVENTOP. c. WaZ ton M uao'er.

Patented Oct. 5, 1954 MECHANICAL PENCIL EMPLOYING CLIP IN ASSEMBLY C. Walton Musser, Philadelphia, Pa., assignor to Prismatic, 1110., Southampton, Pa., a corporation of Pennsylvania Original application October 10, 1950, Serial No. 189,309. Divided and this application July 16, 1951, Serial No. 236,977

1 Claim. (Cl. 12014.5)

The present invention relates to mechanical pencils particularly of the character which select an individual color from a plurality of available colors of leads.

This application is a division of application Serial No. 189,309, filed October 10, 1950, for Mechanical Pencil. Subject matter also divided from the same parent application appears in copending applications Serial No. 236,975, filed 2 cure the helix to the barrel. The clip is also used to retain the helix in rotatable relation to the barrel.

The movement of the lead carriers and related mechanism is described in copending application Serial No. 189,309 filed Oct. 10, 1950, and the detail of this subject matter will not be here repeated. i

The pencil of the invention includes a barrel July 16, 1951, for Collet Guiding in Mechanical 40, a tip 41, a helix 42, a clip 43, a barrel band Pencil, and Serial No. 236,976, filed July 16, 1951, 44, a friction spacer 45, a nut or shoe 46, segfor Lead Reservoir for Mechanical Pencil. ments 4'! and collets 68.

A purpose of the invention is to provide a tank The barrel is very desirably made from a clear extending through the barrel of a pencil from a or transparent plastic, such as polystyrene or clip and to hold the clip in place with a band methyl methacrylate, and includes a generally surrounding the barrel. tubular barrel portion 59, suitably of cylindrical A further purpose is to extend a tang from the exterior contour as shown, having a polygonal clip into an annular recess on the adjacent head interior cross section 5!. 0f the helix to position the helix. Forward of the generally uniform polygonal Further purposes appear in the specification cross section as just described, a forward extenand in the claim. sion 52 is provided of reduced external and in- In the drawings I have chosen to illustrate a ternal diameter. few only of the numerous embodiments in which An abrupt inward cam surface is provided at my invention may appear, selecting the forms 58 between the sides of the polygon of portion shown from the standpoints of convenience in 5t and of portion 52, desirably disposed at some illustration, satisfactory operation and clear steep angle to the axis preferably of the order of demonstration of the principles involved. 45.

Figure 1 is a side elevation of the preferred The forward end of the barrel is provided with embodiment of the invention partially broken the tip 4! which is fastened to the barrel in any away to show the reservoir for spare leads inside suitable manner preferably by a snap action as the tip. later explained. The tip has an inner bore 64 Figure 2 is an exploded perspective, partially which surrounds the reduced portion 52 of the broken away, of the helix and nut assembly of barrel, which then gradually tapers or converges Figure 1. at E5 toward a collet well 66 near the forward end Figure 3 is an exploded perspective partially which again tapers or converges at 61 into a broken away, of the segments, collets and leads center lead guiding opening 68 best seen in Figof Figure 1. ure 5. The exterior portion of the tip gradually Figure 4 is an exploded perspective of the barconverges a 0 w rd h f rward end. rel, clip and tip of Figure 1. To render the tip readily removable and at the Figure 5 is an axial section of the pencil of 40 same time permit it to be inserted easily into Figure 1.

In the drawings like numerals refer to like parts throughout.

The present invention is directed to pencils in which a plurality of colors are available, and especially to those in which a'multiplicity of color selections can conveniently be made. In the prior art, where a variety of colors have been available for selection in a mechanical pencil, the mechanism has been complicated and expensive and the operation has often been inconvenient or unreliable.

In accordance with the invention, the assembly of the components is very conveniently accomplished by using the clip as a fastener to seposition, the interior bore 64 of the rearward portion of the tip is provided with grooves 12 as best seen in Figure 4 which correspond in placement to the positions of the ribs 62 and are sufliciently deep to allow the tip to slide longitudinally over the ribs without undue friction when the grooves 72 are aligned circumferentialy with the ribs 62. Between the grooves 12 are flats or lands 13 which are comparatively shallow, suitably being of the order of a few thousandths of an inch, so that after the tip is inserted in place on the barrel with the grooves 12 corresponding in position with the ribs 62, a slight twisting of the tip with respect to the barrel will lock the tip on the barrel by jamming the outer circumferential edge of the ribs 62 against the lands 13 on the inside of the tip.

The helix 42 comprises an adjustment head 14 having a socket 15 which receives and frictionally holds an eraser 16 and a central inwardly extending screw portion 77 extending through the interior to the forward end of the barrel portion 50 and provided with a helical thread 78 which may extend in either direction but which, to agree with the direction of ratchet used, is left hand as shown.

The forward end of the adjustment head 14 is shouldered at 80 as best seen in Figure 2 and between the shoulder and the screw portion 11 is located a hub 8| of reduced cross section compared to the head and which is suitably positioned immediately inside the rear end of the barrel. The hub has an annular outside groove 82 intermediate between the ends of the hub.

The barrel portion at one position in the circumference as best seen in Figure 4 has an inwardly extending slot 83 and is suitably provided with a recess 84 forward of the slot. The clip 43, suitably of resilient metal such as brass or bronze, has a base portion 85 which fits in the recess 84 and has a transverse tang 86 which extends through the slot 83 and its inner end engages in the annular groove 82 on the hub 8| of the helix. A suitable U-shaped resilient friction spacer 81 as best seen in Figure 2 is placed around the hub between the hub and the barrel with the open portion of the U spanning the tang 36. The spacer 8'! frictionally engages the parts by an amount which is readily predetermined, retards the helix against excessively free rotation in the barrel and prevents plastic from running on plastic.

The press-fitting barrel band 44 surrounds the base portion 83 of the clip and holds the tang in position in the groove 82, and the tang prevents the helix from moving longitudinally as it turns with respect to the barrel.

In operation, the device is assembled by threading the shoe on the helix, and running the helix up close to the rear end. The collets are mounted on the segments. The various segments are then placed around the helix with the aligning projections against the rear end of the shoe, and the driving projection in one of the driving recesses. The spacer 87 is slipped over the hub 8| as by springing from the side, and then the barrel is slipped over the segments, the helix and the spacer, turning the barrel until the barrel slot 83 corresponds in position with the open side of the spacer. The tang of the clip is then inserted through the slot 83 and into the annular groove 82 on the hub of the helix. The barrel band 44 is then pushed over the head of the helix into place around the base of the clip.

The assembl is facilitated by using the tang of the clip to retain the parts in assembled relation and to permit relative rotation of the helix with respect to the barrel.

In view of my invention and disclosure variations and modifications to meet individual whim or particular need will doubtless become evident to others skilled in the art, to obtain all or part of the benefits of my invention without copying the structure shown, and I, therefore, claim all such insofar as they fall within the reasonable spirit and scope of my claim.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

In a mechanical pencil, a barrel having an open end at one end and a tip adapted to guide leads at the opposite end, there being an opening in the side of the barrel near the open end, lead carriers in the barrel movable longitudinally, adjustment means for the lead carriers including an adjustment head having a portion protruding beyond the open end, extending into the open end and having an outwardly directed circumferential groove in line with the opening in the side of the barrel, a clip located outside the barrel and having a tang which extends through the opening in the barrel and into the groove in the adjustment head and a band extending around the barrel adjacent the open end and around the clip outside the tang, holding the clip in place.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,270,914 Zimbdars July 2, 1918 1,426,744 Keeran et al Aug. 22, 1922 1,827,324 Lynn Oct. 13, 1931 1,838,747 Deli Dec. 29, 1931 1,839,066 Vivian Dec. 29, 1931 2,451,111 Nichols Oct. 12, 1948

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