US2148866A - Guide tube for mechanical pencils - Google Patents

Description

| LANOIE Feb. 28, 1939.

GUIDE TUBE FOR MECHANICAL PENCILS Filed Dec. 20, 1937 INVENmR.

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Patented Feb. 28, 1939 UNITED STATES "GUIDE TUBE FORMECHANICAL *PENCILS LouiseA. Lanoie, Providence,.-R.1I., .assignortofLew Mfg. 00., :Providence, R. -I.,.a partnership composed o'fLouis A. Lanoie andJames T.-Murphy Application December 20, 1937, SeriaI No. 130;724

4: Claims.

"This invention relates to a mechanical pencil, more particularly to the =guide=tube for directing the movement of the leadcarrier and/or ejector in the operation "of the pencil; and has for'one of its objects theprovision of aisimple means of :preventing collapsing-ofthe tubewhen' it-is'forced 'into *thepointend of the pencil.

Another object of the invention is the spreading of the stock ,at the-end portion of the guide tube in such a-mannerithat the contacting surface of the guidetube "with the bore "of thepoint i remains substantially cylindrical and'well supported.

Another object of the invention is the spreading of the stock at the endportion of the guide "tube bymerely squashing or pressing the marginal edges of the slot at the end ;portion to cause them to come into engagement one with the-other.

Another object of the invention is to move the opposite edges of the stock of the guide tube into engagement in an interlocking arrangement.

With these and other objects in view, the invention consists of certain novel features of construction, as will be more fully described, and particularly pointed out in the appended claims.

In the accompanying drawing:

Fig. 1 is a sectional view of the point with the guide tube inserted therein;

Fig. 2 is a view similar to Fig. 1 but on a much larger scale showing the guide tube fragmentally;

Fig. 3 is a sectional view on line 3-3 of Fig. 2;

Fig. 4 is a section of the guide tube online 55 of Fig. 2 with the point omitted;

Fig. 5 is a section on line 5 5 of Fig. 2 on a greatly enlarged scale;

Fig. 6 is a perspective view of the guide tube.

In the use of slotted guide tubes for mechanical pencils, it is necessary to so support the tube where it is inserted into the point that the edges of the slot will not be so moved toward each other as to prevent free movement of the carrier; tube or ejector in the pencil. Also, to so support the tube that it may be forced with greater pressure into the point to hold it firmly therein than could be done were the tube open so that the tube might be collapsed: In order'that this result might be accomplished, it has been usual to cut outof the sheet stock from which the tube was formed projections to abut when the sheet stock was rolled into the slotted tube formation. More recently it has been desirable to provide the guide tube in a more or less continuous length and then close portions of the slot at the end of the section used such as in Patent No. 2,093,919,

with-which 'I am familiar; "but inorder to improve upon the structure of this patent and makespin- 'ningpr rotation "of the tube to provide such a closure*thereinunnecessary, I have so arranged that'by simplepressing on the marginal edges'o'f the tube 'atthe'endthe stock'may be spread so that its portions will contact and prevent collapsing of the slot. Also, the point of pressure is so arranged that thespreading of the stock occursin such a'mannertha't the'tubeis-supported "in a cylindrical line at the edges; and thefollowing is a more detailed "description of the present embodiment of this invention, illustrating the preferredmeans by whic'hthese advantageous results may be accomplished:

With reference to the drawing, designates the point ofa'mechanical pencil whichis provided witha b'ore H of asize to accommodate'the'le'ad to be ejected therefrom and "is also provided with a larger bore l2 providing by means of the difference in the bores a shoulder 13 in the point member of the mechanical pencil. The outer surface is tapered as at M and provided with a reduced cylindrical portion l5 for fitting into the shell of the pencil, as may be desirable. The guide tube seen and designated in Fig. 6 generally I6 is formed up from sheet stock of a flat ribbonlike shape having parallel edges, the same being bent into the form of a tube with these edges l1 and I8 parallel and spaced to provide a slot I 9 running lengthwise of the tube. A tube of this character may be formed in any desirable length and then cut into individual lengths depending upon the length desired to be incorporated into a particular mechanical pencil movement,

Were the end of the tube, such as shown in Fig. 6, inserted into the bore 12 its edges would be moved toward each other and its inherent tendency to expand would be all that afforded a grip of its outer surface and the surface of the bore I2. Besides the moving of these edges together might jam the carrier or ejector of the mechanical movement. Accordingly, in order that no closing by reason of insertion into the bore l2 may be had, I press the marginal edge portions at each edge of the slot at the end which is to be inserted into the point so as to provide depressions at spaced intervals along the tube and in staggered relation as regards the opposite margins of the slot and at the same time cause the stock to be spread from one edge of the tube toward the other edge, each forming a serpentine path with the lobes of one extending into the hollows of another into contact, so

that the opposite edges support each other, and

I locate the points of pressure to provide the projections sufficiently back of the edges I1 and I8 of the tube that the portions 2| of the tube remain substantially in the same circumferential line as the outer surface 22 of the tube. Thus, the surfaces 2| are in the same circumferential line as the outer surface 22 of the tube and form a point of support when the tube is forced into the bore I2 so that there is no chance of collapsing of the tube, and if for any reason the point 2! may be slightly inward from the circumferential line 22 of the tube, the pressure will cause it to be forced outwardly so that it will come into firm contact with the walls of the bore l2 and thus a support at substantially all angular positions from the center to the circumferential line of the tube is had with the bore [2. The tube is thus well supported against collapsing and appreciably no change takes place between the parallel edges I1 and N3 of the guide tube from their position as formed when the tube is inserted into the bore I2.

Also, by reason of the serrated path of the contacting edges an increased line of support between them is had and an interlocking relation is had against relative axial movement of the edges of the tube at the time of forcing the same into the bore I2.

The foregoing description is directed solely towards the construction illustrated, but I desire it to be understood that I reserve the privilege of resorting to all the mechanical changes to which the device is susceptible, the invention being defined and limited only by the terms of the appended claims.

I claim:

l. A guide tube for a mechanical pencil adapted to be immovably seated in the point member of the pencil comprising a tubular body portion having a longitudinal slot with the opposite marginal edges of the slot adjacent one end of the tube compressed back of the marginal edges and in staggered relation and to an extent to spread the stock at the marginal edges into the previous slot in staggered projections and into closely adjacent interlocking relationship to prevent closing of the slot by compression of the tube at this location.

2. A guide tube for a mechanical pencil adapted to be immovably seated in the point member of a pencil comprising a tubular body portion having a longitudinal slot with portions of the opposite marginal edges of the slot adjacent one end of the tube and in staggered relation extending toward the opposite margin of the tube into closely adjacent interlocking relationship to prevent closing of the slot by compression of the tube at this location.

3- A guide tube for a mechanical pencil adapted to be immovably seated in the point member of a pencil, comprising a tubular body portion having a longitudinal slot with portions of material of the opposite marginal edges of the slot adjacent one end of the tube extending into the slot and into closely adjacent relationship with each other and with the outer surfaces of said portions substantially flush with the circumferential surface of the tube.

4. A method of closing an end portion of a mechanical pencil guide tube formed of sheet stock and provided with a longitudinal slot extending from end to end, consisting of forcing staggered portions of the material atthe marginal edges of the slot adjacent one end of the tube with suilicient pressure to spread said portions of material to extend in staggered projections into closely adjacent interlocking relationship.

LOUIS A. LANOIE.

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