US1956271A - Mechanical pencil - Google Patents

Description

April 24, 1934. cHEsLER MECHANICAL PENCIL Filed oct. 1a, 1930 4 Sheets-Sheet l INVENToR isidaf [Yieslef BY AWS Alpr'il 24, 1934. l. CHESLER MECHANICAL PENCIL Filed Ost. l18 1930 4 Sheets-Sheet 2 /z'dar (les/er BY ATTORNEY April 24, 1934'. CHESLER 1,956,271

MECHANICAL PENCIL 4 4Filed Oct. 18, 1930 4 Sheets-Sheet 3 l'dor ('/zsler INVENTOR l BY ATTO NEY 4 sheets-sheet 4 Filed oat. 18, 1930 5 4 3 7 n0 d mL w ,4 Q 3 a w 4 5 w 5 awww@ vzw /dar flies/ei' IN VENTOR BY ATTORNEY Patented Apr. 24, 1934 PATENT GFFICE MECHANICAL PENCIL Isidor Chesler, west orange, N. J., assigner to Eagle Pencil Company, New York, N. Y., a corporation of .Delaware Application Octobelrl, 1930, Serial No. 489,546

9 Claims.

'I'his invention relates to mechanical pencils and to methods of making the same.

Mechanical pencils are manufactured in great quantities to sell at moderate and low prices and makers have been continuously faced with the problem of providing the demand for relatively cheap pencils capable of giving good service without getting out of order. A commonform of mechanical pencil is provided with a lead propelling l rod, a guide tube therefor, a screw for 'advancing the lead rod, and a barrel which encloses the foregoing and other parts which are essential and peculiar to any particular design of mechanical pencil. In many types' of pencils the barrel of a 1l pencil performs the function of a grip and is provided with a tip at its lower end and other appendages which hold the working parts in assembled relation. The barrels of many of these pencils are at the present time made from wood or o! metallic tubing and some of the pencils are provided with screw tubes by which the lead propellingvrods are advanced. In the interest of low manufacturing costs it has been the practice to provide crude fits of the tip, through which the lead travels at the lower end of the pencil, with the guiding tube and barrel. Also, the screw tube has been poorly constructed and fitted. Because of these conditions and the lack of the exercise of the care necessary for the correct assembling of parts, the propelling and retracting actions are often accompanied by an appreciable amount of friction. The result is that wear and incident abuse because of hard operation frequently limit the life of la pencil possessing such structural characteristics.

It is, therefore, the object of my invention to overcome defects of the kind referred to and to enable the production of an inexpensive mechanical pencil which has moving parts possessing smoothness in operation.v To this end I have eliminated the separable barrel and screw and have made these members as one member. A perfect screw of rigid construction is obtained. Also, undesired seams and loose fits are obviated,

46 and by such a construction the tip through which the lead passes at the end of the pencil may be integrally associated with the barrel.

Another object of my invention is to provide a mechanical pencil having a moulded grip or 60 barrel, and methods by' which such a pencil may be flawlessly made in large quantities on an economic production basis. The barrel is moulded or cast from plastic material with the hollow tip through which the lead passes aiiixed thereto as-"an integral part. In one of the methods by (Cl. 1Z0-18) which a moulded barrel having an internal screw is formed I have developed a novel method of casting within a portion of a. cavity, which method has uses other than for the manufacture of pencils.

With these and incidental objects in view the invention involves certain novel features of ccnstruction and combination of parts, the essential .elements of which are set forth in the appended claims and a preferred form of embodiment of which is described hereinafter with reference to the drawings which accompany and form a.l part of the specification.

In the drawings:

Fig. 1 is a longitudinal section of a mechanical 70 pencil embodying the present invention.

Fig. 2 is a longitudinal section through the lower end of the pencil with the c'ore used in its manufacture in place.

Fig. 3 is a section on line 3-3 of Fig. 2.

Fig. 4 is a cross-section on line 4-4 of Fig. 3.

Figs. 5, 6, 7 and 8 are cross-sections on line 5 5, 6-6, .7-7, and 88 respectively of Fig. 1.

Fig. 9 is a longitudinal view, partly in section, of the guide tube, lead carrying tube and lead propelling rod.

Fig. 10 is another longitudinal view of the members illustrated in Fig. 9.

Fig. 11 is a cross-section on line 11-11 of Fig. 10.

Fig. 12 illustrates how the barrel may be moulded. t

Fig. 13 illustrates the barrel and tip of the pencil shown in Fig. 12 with the core removed.

Fig. 14 is a longitudinal section of the tip of 90 Figs. 12 and 13 before it is mounted on the core.

Figs. 15, 16, 17, 18 and 19 are illustrative of the various elements used in the method of moulding the barrel of the pencil illustrated in Figs. l, 2. 3 and 4.

Fig. 20 illustrates the relation of a core in the barrel of a pencil designed for a mechanical movement different from that of the pencil of Fig. 1.`

Fig. 21 is a portion of the barrel of the pencil 100 of Fig. 20 with its lead controlling parts in place.

Fig. 22 is a section on line 22-22 of Fig. 21.

l Figs. 23 and 24 are differentdviews of the lead controlling parts for the pencil illustrated in Figs. 21 and 22.

Mechanical pencils known as the propel-repelexpel type are usually provided with a guide tube having a longitudinal slot through which projections mayy extend for engaging a helical groove. One of these projections is afxed to a. Il.

` tube.

lead carrying tube which is adapted to engage the lead. This tube is propelled along the axis of the guide tube as the result of a rotary motion between the guide tube and the barrel or sleeve of the pencil as the projection travels in the helical groove. A rod with a similar projection is provided for expelling the lead from the tube. The functioning members of some other types of mechanical pencils omit the lead expelling rod or the lead carrying tube but the member which controls the position of the lead within the pencil is carried in either direction along the axis of the pencil, depending upon the direction of rotation of the guide tube relative to the barrel. As will subsequently appear, certain features of my invention embody improvements for any mechanical pencils of types similar to those alluded to hereinabove.

While certain features of my invention are useful in different types of mechanical pencils, I have chosen to illustrate my invention embodied in what is known as a propel-repel-expel type of pencil.. In this latter type of pencil the lead expelling rod is mounted for sliding movement within the lead carrying tube and the projection carried by the lead expelling rod extends through a, slot in the lead carrying tube and the longitudinal slot in the guide tube and into a helical groove. These members are illustrated in all three of the pencils shown in the drawings. In the ordinary use of the pencil, the projection from the lead carrying tube and the projection 'from the lead expelling rod are spaced from each other a distance equivalent to two convolutions of the helical groove, and in this relation the lead carrying tube is open for the reception of a lead. 'Ihis relation is maintained so long as there is suiiicient lead to be useful for writing purposes. When the lead carrying tube and lead expelling rod have traveled to the tip end of the pencil as the lead has been used, further travel of the projection on the lead carrying tube is terminated.

In the pencils illustrated in Figs. 1, 9 and 10 the projection on the lead carrying tube enters a recess at the end of the helical groove and this recess permits the projection to rotate freely, and prevents further advancement of the projection and lead carrying tube. When the projection from the lead carrying tube has reached the bottom of this recess and the rotation of the guide tube is continued, the projection from the lead expelling rod will continue to travel along the helical groove and move the lead expelling rod relative to the lead carrying tube, with the result that the lead is expelled from the lead carrying This condition of the pencil is illustrated in Fig. 1. After a lead has been expelled and it is desired to insert new lead, the movement of the guide tube in the barrel of the pencil is reversed and the projection from the lead expelling rod is caused to travel in the groove in the pencil in a direction away from the tip. When the lead expelling rod has been moved sufliciently,

' a lead may be inserted in the end of the lead carrying tube. The lead expelling rod moves relatively to the lead carrying tube during one revolution of the guide tube and, thereafter, further rotary movement would cause the lead expelling rod to cairy the lead carrying tube with it and cause the projection from the lead carrying tube to engage the helical groove of the pencil. In this relation the two projections are spaced from each other two convolutions of the helical groove and the lead may be carried back into the pencil.

The pencil of the type illustrated in Figs. 1, v9 and 10 has members associated together and capable of coacting in the manner above outlined. In this pencil the guide tube 10 has a longitudinal slot 11 along which the projections of the lead carrying tube and lead expelling rod travel as the guide tubev is rotated relativeto the sleeve or barrel 12. The lead carrying tube 13 has a longitudinal slot 14 through which extends the projection 15 which is mounted upon the lead expelling rod 16, This projection 15 is in the form of a looped member having smooth rounded edges adapted for easy movement Within the helical groove 17 of the pencil. This loop l5 may be a part of the lead expelling rod 16 or may be merely a looped element secured thereto. The slot 14 is of such a length as to permit the projection 15 to move the pitch of the helical groove without causing movement of the lead carryingl tube.

As may be -seen in Figs. 1, 6, 9, 10 vand 11, the lead carrying tube 13 has a projection which is formed by a pair of ears extending from the material of the tube beyond the `tubular dimension of the guide tube 10. These ears 18, 19 are shouldered `to support a washer 20 and extend through and are bent over the washer.v The washer preferably is round and of such a diameter as to easily engage the vhelical groove 17. The design of -this projection y,and the function which it serves is a feature of the present invention. It is admirably suited to afford smooth action in the operation of the pencil as it travels along the helical groove. Frequent cause of failures of mechanical pencils of the propelrepel-expel type are directly assignable to weakness in the forms of projections used and to the lack of appreciation of the sliding fit conditions existing when the projection passes. from the helical groove to the recess 21 near the lower end of vthe pencil. The form of the projection illustrated gives sufficient strength to withstandthe stresses likely to be placed upon the projection and its width and form render it well suited for smooth entry into the helical groove from the clearance rece/ss and for guidance by the thread.

As illustrated in Fig. 1 the lead carrying tube and lead expelling rod have been moved to their extreme positions at the lower end of the pencil. In this position the projections are in their closest relation; that is, their spaced distance is yso the pitch of the helical groove 17. From this position the lead expelling rodn may be drawn into the lead carrying tube by the rotation of the guide tube while the projection from the lead carrying tube rotates freely within recess 21. When projection 15 has moved the distance of the pitch of the helical groove further rotation.

This movement has occasioned friction and has been the cause of failures but my pencil is capable of smooth and uninterrupted motion.

In addition to the smoothness of operation contributed because of the form of the. projection, the connecting together of the tip 23 with the barrel 12 as an integral member without intermediate seams or laps is a contributing factor. This enables the making of the helical groove continuous with the recess.

In prior practices the tip of the pencil through which the lead passes was made up in some cases, of more than one member and the tip was connected to a wooden barrel. The member bearing the helical groove was independent of the wooden barrel and usually within `a sleeve or in the form of a spiral tube. The recess in which the projection from the lead carrying tube entered from the helical groove often consisted cf merely an interruption of the helical groove. The poorly constructed joints which frequently exist in such pencils are eliminated in my pencil in which the helical groove is integrally asspciated with the barrel and the tip is joined to the barrel as one member. This construction has been made possible by the development of methods, which will later be described, which make it possible to mould the barrel from a composition such as, for example, a phenolic condensate product.

In the mou'lding operation the tip is `ioined together with the barrel as one member and the larger bore within the tip is a continuation of the helical groove in the barrel of one type of pencil or of the bore in the barrel in another type of pencil. In addition to eliminating the use of more than one member to serve for a groove and as a. grip by which the pencil may be manipulated, I have provided a new method which enables the tip to be made of one piece. This feature in itself is an economical saving in the cost of manufacturing mechanical pencils.4

Having reference to Figs. 1, 2, 3 and 4 which relate to one method of making the pencil, the tip 23 is turned from a single member, preferably 'a metallic member. This member is drilled for the purpose of forming the recess 21 which receives the projection carried by the lead carrying tube, Fig. l. It may also be drilled at 25 for receiving the lower end of the guide tube 10. Although it is not necessary that the guide tube extend into the tip, it is an advantage of construction to provide a bearing at 25 for supporting the lower end of the guide tube. A bore 26 of less diameter is provided for receiving the lead carrying tube when the tube is moved to the lower endof the pencil as illustrated in Fig. 1.' Of course, the tip is provided with the usual hole 27, through which the lead passes. The tip 23 is shouldered at 28 in order that it may be rmly ,held by and embedded within the moulded composition of the barrel 12. The tip which has just been described is illustrated in detail in Figs. 1, 2, 3, 4,75 and 6, and the method by which the barrel of the pencil is moulded to this tip is illustrated lin steps in Figs. l5 to 19 inclusive. 1

As illustrated in Fig. 1, the upper end of the pencil has a rubber supporting ferrule 29 which engages by friction a cap 30 which is secured to the end of the guide tube 10 by means of a pin 31. By rotating the ferrule 29 the lead carrying tube may be made to travel along the guide tube in either direction depending upon the direction of rotation of the guide tube relative to the barrel.

The mould in which the barrel of the pencil may be formed and connected with the tip is illustrated in Fig. 18. Before moulding the barrel,

the tip 23 is engaged by means of a core 33 which` is a screw for forming the internal groove of the barrel, Fig. 16. Preferably the core 33 is tapered slightly at the end which engages the bore 21 in order that a tight iit of the core with the bore may be assured. Figs. 2 and 3 have been laid out on an enlarged scale in order to make clear theA relation of the core with the bore. After the tip and the core have' been engaged in this manner a piece of malleable metal 35, such as soft aluminum, Fig. 17, is driven through a hole 36 in the skirt 37 of the tip 23 in such a location as I to enter and fill the groove between successive turns on the core 33. As assembled, the tip 23 and the core 33 are placed within a mould, Fig.

18, with the tapered end of the tip 23 in close contact with, one end of the mould in such a manner as to close that end. 'Ihe plastic material which is to form the barrel of the pencil is then forced into the mould and caused to take the form of the mould, as the result of sufiicient pressure to insure that a perfect cast of the barrel is obtained. 'I'he piece of malleable metal 35 will operate to prevent the entrance of the plastic material along the groove of core 33 beyond itself and therebyv prevent the entrance of the plastic material to the recess 21. In the finished product, after the composition has set,`the piece 35 will be the end of the internal thread of the barrel, a portion of which extends within the bore 34, Fig. 4. 'I'his construction insures a continuity of the helical groove 17 to a .definite point within the recess 21 with moulded composition extending within the metallic tip member as far as the piece 35.

When the moulded composition has set, the mould may be removed anw the core removed from within the barrel. The barrel is thenv ready for receiving the movable parts of the mechanism which have been describedvhereinabove.

The foregoing method of producing the barrel of moulded composition involves the solution of the problem of moulding or casting within a cavity. A tight ilt at the periphery of the thread of the core 43 with the bore or recess 21 insures that plastic composition may enter the bore only along the groove of the core, and the distance of the material'forms` the thread within the bore of' the recess.

Another method by which the barrel may be moulded is illustrated in Figs. l2 and 13. 'Ihis method requires the use of a metallic tip 40 which has a portion of a thread 41 tapped therein. 'I'his thread extends to the recess 42, Fig. 14. In this latter'method of moulding, the core 43, Fig. 12, is. screwed into the end of the tip. The core and tip are placed in this condition within a mould similar tol that used in the method of moulding above described. After the moulded composition filled the mould and has set about the tip and core, the assembled members may be removed from the mould and the core 43 withdrawn. As illustrated in Fig. 13 this method results in the production of a barrel and tip integrally associated with an internal helical groove 44.01? the composition of material continuing within the metallic tip.

While there arel various types of mechanical pencils employing different formsv of movable partsfor controlling the position of a lead which may be improved by the use of my invention, I

have chosen to illustrate the application of my f invention to` a pencil of the propel-repel-expel type, since this type of pencil embodies mechanical features in addition to thov which are characteristic of other types of pencils. In the torepermitting the projection from the lead carrying tube to rotate when it has reached the lower end of its path of travel.

In Figs. 20 to 24, inclusive, vI have illustrated another kind of propel-repel-expel type of pencil which does not embody the use of a recess for receiving the projection from the lead carrying tube. The tip 45 for this pencil is, therefore, of a different character. This tip is turned and drilled in a manner similar to the tips previously described but in View of the fact that less machining is necessary its cost to manufacture is much less. This tip likewise may be made from a single piece of material such as brass, German silver, or other material having suilicient strength. It is tapered on its outside surface at its lower `end and has drilled therein a hole 46 for permitting the passage of a lead. The hole 47 is adapted to receive the lead carrying tube 48 when that tube has descended to the tip end'of the pencil, Fig. 21. It is convenient to turn the upper end of the tip 49 in the form of a hollow cylinder. For moulding the barrel 50 of the penciltlie tip is engaged by a core 51 in the manner illustrated in Fig. 20 and the tip and core are placed in a mould similar to that illus' trated in Fig. 18. The process of moulding is thereafter similar to that described hereinabove. In order to obtain a tight t between the tip and the core the pilot 52 of the core is tapered' p slightly. /While the bore of the cylinder 49 could be tapered in lieu of tapering the pilot, it is preferable to taper the pilot since such procedure is less expensive. Even though high pressures are utilized in moulding the phenolic condensate or other composition the fit between the tip and the core is such as to prevent any extrusion of the moulded composition into the bore of the tip.

The shoulder 53, may be turned and it serves for interlocking the tip with the barrel of the pencil.

When the barrel has been moulded and has set the core 51 is removed and the barrel is ready to receive the moving parts which control the 4positionof the lead. Referring to Figs. 21, 22,

23 and 24, these parts comprise the lead carrying tube 48 which is mounted for sliding movement along the axis of the slotted guide tube 55 as the guide tube is rotated thereby causing the projection 56 to travel along the helical groove 57 and actuate the lead carrying tube. In the mechanism illustrated, the lead expelling rod 58 in separable from thelead carrying tube 48 but it `also is actuated along the axis of the pencil as the helical groove.

l may be availed of for improving many different types of pencils, it is unnecessary to refer to additional applications of the invention in other mechanical pencils. I desire it to be understood v that it is not-intended to conne the invention to the specific forms of improvements herein disclosed for it is susceptible of embodiment in various forms, all coming within the scope of the claims which follow.

I claim:

1. In a mechanical pencil, the combination comprising an internally threaded sleeve and a slotted guide tube mounted for rotation Within said sleeve, a lead carrying tube slidable within said guide tube and having a projection, said projectioncomprising a pair of ears holding a washer having a diameter substantially equal to the width of the groove of the thread in said sleeve with which it is in engagement, and a lead propelling rod extending within said lead carrying tube, said lead propelling rod having a projection for engaging the thread of said threaded sleeve. I f

2. In a mechanical pencil, the combination comprising an internally threaded sleeve and a slotted guide tube mounted for rotation within said sleeve, a lead carrying tube slidable within said guide tube' and a lead propelling rod within said lead carrying tube, said lead propelling rod and said lead carrying tube each having a projection engaging the vthread of said threaded sleeve, at least one of said projections including a circular disc working in the groove of the thread and of a diameter nearly approximating the Width of such groove. y

3. In a mechanical pencil, thev combination comprising a barrel whereby the pencil may be gripped, said barrel having an internal thread,

a pencil tip held in locked relation by said barrel,

said tip having a hole for the passage of lead and a recess threaded in continuation of the internal thread of said barrel, a guide tube within said barrel, and a lead carrying tube having a projection adapted to follow the thread of said barrel and threaded recess upon rotation of the lead carrying tube.

v4. In a mechanical pencil, the combination comprising a barrel whereby the pencilvmay be gripped, said barrel being of a moulded composition and having an internal helical thread, a lead carrying tube having a projection engaging the helical thread, a slotted guide tube, a lead expclllng rod within said lead carrying tube, said lead expelling rod having a projection engaging the helical thread, and a tip at one end of said barrel, said tip comprising a single body with a hole through its axis having diierent diameters, the different diameters being provided for receiving the lead, lead carrying tube, guide tube and the projection of said lead expelling rod respectively.

5. Ina mechanical pencil, the combination comprising a barrel whereby the pencil may be gripped, said barrel being of a moulded composition and having a bore threaded internally, a lead carrying tube having a projection engaging the helical thread, a slotted guide tube, a lead expelling rod within said lead carrying-tube, said lead expelling rod having a projection engaging the helical thread, and a metallic tip xedly assocated with said barrel, the moulded composition of said barrel being in engagement with a portion of the exterior of said tip, said tip having a clearance recess disposed beyond the end of the threaded bore of the barrel for enabling the travel of the projection of the lead carrying tube into the tip and being suitably holed for receiving the lead and lead carrying tube.

6. In a mechanical pencil, the combination comprising a barrel whereby the pencil may be gripped, said barrel being of a moulded compositinuation of the thread of the bore of the barrel,

and holed for receiving the lead and lead carrying tube.

7. In a mechanical pencil, the combination comprising a sleeve having an internally threaded bore and a guide tube mounted for rotation within said sleeve, a lead carrying tube, a lead propelling rod within said lead carrying tube, said lead carrying tube and said lead propelling rod each having a projection engaging the thread of said sleeve, said projections being spaced from each other a distance necessary to expel a lead from the lead carrying tube by movement of the lead propelling rod relative tothe lead carrying tube, a metal tip having a hole for laterally supporting a lead disposed in said lead carrying tube, said tip being ilxedly attached to said sleeve and having a clearance recess beyond the helical groove of the threaded bore of said sleeve, said recess being adapted to receive the projection on said lead carrying tube to enable rotation thereof during movement of the lead expelling rod in relation to the lead carrying tube.

8. In a mechanical pencil the combination with a barrel of plastic composition having an integral internal helical thread, of a metallic tip having a passage for the lead of the pencil, said barrel including an integral portion interlocking with the tip to block disassembly of the tip and barrel and retain the tip in proper position with respect to the barrel and a lead carrying member including a portion working in the groove of the thread.

9. In a mechanical pencil the combination with a barrel of plastic composition having an integral internal helical thread of a metallic tip having a passage for the lead of the pencil, said barrel including an integral portion interlocking with the tip to block disassembly of the tip and barrel and retain the tip in proper position with respect to the barrel, said tip having an external annular groove therein receiving an integral internally circular yinwardly extending portion of the plastic barrel.

ISIDORl CHESLER.

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