US3076437A - Writing instrument - Google Patents

Description

Feb. 5, 1963 c. N. JOHNSON WRITING INSTRUMENT 4 Sheets-Sheet 1 Filed July 28, 1958 FIGJ FIG.|O

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Feb. 5, 1963 c. N. JoHNsoN WRITING INSTRUMENT Filed July 28, 1958 4 Sheets-Sheet 3 Feb. 5, 1963 c. N. JoHNsoN WRITING INSTRUMENT 4 Sheets-Sheet 4 Filed July 28, 1958 United States Patent 3,076,437 WRITING INSTRUMENT Clifford N. Johnson, 7421 Pleaseway Drive, St. Louis 20, Mo. Filed July 23, 1958, Ser. No. 751,412 3 Claims. (Cl. 12d- 22) This invention relates to a writing instrument wherein the writing unit is allowed to fall by gravity a limited predetermined distance beyond the forward end or tip of said writing instrument when the projecting mechanism is actuated. In particular, this invention relates to a mechanical pencil wherein the writing unit or lead is allowed to fall by gravity a limited predetermined distance, which can be adjusted as desired, beyond the tip of the pencil when the Writing unit stop or lead stop is actuated.

This application has subject matter in common with my co-pending application Ser. No. 587,094, tiled May 24, 1956, now Patent No. 2,854,950.

The use of extra thin lead in mechanical pencils has become increasingly popular. This lead is approximately 0.036 inch in diameter and is frequently broken due to the over extension thereof from the forward tip of a pencil. It is estimated that over titty percent of such lead is wasted since it is broken off so frequently in use. Present mechanical pencils feed the lead from the forward end of the pencil in many different ways, such as by spiral means actuated by rotation, by button means which when pushed positively moves the lead forwardly step by step, or by clutch means actuated by rotation or by a spring clutch as normally found in mechanical drafting pencils. With all of the present feed arrangements, the amount of lead which extends beyond the forward end of the pencil is not positively measured by means projecting externally from the pencil, but is visually estimated or moved by means withinv the pencil itself. Either way, there is no assurance that the desired amount of lead will extend forwardly from the end of the pencil.

One of the principal objects of the present invention is to positively measure by externally projecting means the amount of lead which extends externally downwardly `from the forward end of a mechanical pencil, and to maintain that amount regardless of repeated actuation of the lead forwarding mechanism.

Another object of the present invention is to provide retractable stop means which is projected beyond the writing end of a Writing instrument for preventing the writing unit from falling by gravity beyond a predetermined distance from the tip of the instrument regardless I"of how many times the lead forwarding mechanism may be actuated. Another object is to provide in a writing instrument means normally positioned within said instrument which can be projected externally thereof to limit the distance which the writing unit is allowed to project from the tip of the writing instrument and to limit this in an adjustable manner. Another object is to provide actuating means which when operated does not positively act upon or move the writing unit but simply allows the writing unit to move by gravity to its predetermined writing position. This eliminates the necessity of providing means for pushing the writing unit or lead to its new or projected position.

Another object is to provide a simple and economical commercial construction having a self-contained writing unit assembly and magazine assembly which can be easily assembled into the barrel.

Another object of the present invention is to provide a mechanical pencil wherein lead is allowed to move by gravity to its writing position upon actuation of the projecting mechanism. Another object -is to provide a mechanical pencil wherein an additional supply of leads from the lead magazine will by virtue of being located one ICC above the other in the Ilead tube and resting upon one another cause the service lead to drop to its new position quickly because of the additional weight thereon when the projecting mechanism is actuated.

Another object is to provide a lead clutch or collet, part of which is located outside of the pencil barrel or casing which will firmly grip the service lead at only one point said point being located adjacent to the writing tip. Another object is to provide lead adjusting means for varying the amount which the externally projecting lead stop will allow the writing uni-t to fall or project beyond the writing tip.

Another object of the present invention is to provide a magazine for a repeater-type pencil having guide means therein for automatically feeding leadv within the maga*- zine to the central opening in a positive and guided manner utilizing the fact that a right-handed person normally rotates the pencil counterclockwise in his hand when looking at the eraser end when bringing a more pointed edge into contact with the paper.

Another object is to provide a large capacity magazine wherein the leads are maintained in a predetermined upright position and are guided and properly oriented with respect to the central opening. j

These and other objects and advantages will become apparent hereinafter.

The invention also consists in the parts and in the arrangements and combination of parts hereinafter described and claimed. In the accompanying drawings which form part of this specification and wherein like numerals and letters refer to like parts wherever they occur:

FIG.1 is an enlarged longitudinal cross-sectional view of a writing instrument embodying the present invention showing the lead or writing unit in its writing position after it has been worn to some extent, the dotted lines lshowing the extended position of the lead stop,

FIG. 2 is an end view of the writing tip of the instrument shown in FIG. 1,

FIG. 3 is a greatly enlarged fragmentary longitudinal cross-sectional view of the writing end of the instrument,

FIG. 4 is an enlarged fragmentary partial section of the writing end of the instrument with the lead stop in its projected position,

FIG. 5 is a view similar to FIG. 4 but with the -jaws of the clutch in their forward and open position,

FIG. 6 is a greatly enlarged elevational viewof the unitary writing assembly,

FIG. 7 is a cross-sectional view taken along the line 7.-7 of FIG. 6,

FIGS. 8 and 9 are detailed views of the shoulder bearing and the lead selector with an integral extruded guide tube, respectively,

FIG. l0 shows the upper end of the magazine before the friction tube is applied,

FIG. 11 is a sectional view along a slot showing the friction tube assembled with said magazine,

FIG. l2 is a view of the instrument with the cap removed and in erasing position,

FIGS. 13 and 14 are fragmentary sectional views of a modied eraser holding means wherein the eraser has a vthreaded cap which is threaded into the magazine,

lFIGS. l5 and 16 are end views similar to FIG. 2 showl ing a pair of modified clutch jaws having a square central opening which automatically compensates for variances inthe size of the lead, as shown in FIGS. l5 and 16,

FIG. 17 is a fragmentary longitudinal cross-sectional view showing my modified magazine with guide means therein,

FIG. 18 is a cross-sectional view taken along the line 18-18 of FIG. 17, and

FIG. 19 is a fragmentary longitudinal cross-sectional view of the modied magazine without the guide means and showing one position which an unguided piece of lead might assume.

Referring now to the drawings in detail, it willbe seen that the embodiment of the invention which has been illustrated comprises a writing instrument 1 having a casing 2 with a projecting mechanism 3 and clutch 4 therein. The casing 2 comprises a barrel 5 and a cap 6 thereon with a unitary writing unit assembly 7 and a magazine 8 therein.

The Cylindrical barrel has internal threads 9 at its forward end for receiving the writing unit assembly 7. The upper portion of the barrel 5 is provided with a plug 10 which slidably receives the magazine 8, said plug 10 being slightly larger in diameter than the barrel 5 to provide a bearing surface 11 for the inside of the push cap 6 having a pocket clip 12 thereon. The barrel 5 is basically tubular and preferably cylindrical for ease in manufacturing and printing names or advertisements thereon.

The writing unit assembly 7, best shown in FIGS. 5 and 6, comprises a clutch closing tube 13, a clutch 4 with a Vforward tip 14, a lead selector 15 and various other parts. lThe clutch closing tube 13 has threads 16 thereon, a tapered outer surfacey 17, a rear abutment 18, and a forward portion 19. The clutch 4 has an axial opening 2t) therethrough. The clutch closing tube has an opening therethrough and a rear support 21` and a forward surface 22. The clutch 4 slidably sets within the clutch tube -13 and is provided with a plurality of jaws 23 having teeth 24 at their forward end for gripping the writing unit or lead 25. The outer inclined surfaces 26 of the jaws 23 slide with respect to the surface 22. One of said jaws `23 is provided -with a slot 27 having a bottom 28. The rear portion of said clutch 4 is provided with internal threads 29 for receiving the forward end of the lead Vselector 15, which is provided with an enlarged head or rear portion 30 with an opening 31 therethrough and a surrounding concave or conical surface 32.

A clutch closing spring 33 is mountedv between the rear A'surface 1:8 of the clutch closing tube 13 and a rotatable clutch adjusting nut 34 for normally biasing said clutch 4 and nut 34 upwardly. A vsleeve bearing 35 having a shoulder 3.6 thereon is slidably mounted on Said lead selector 15 which is .circumscribed by a lead stop spring Y37-positioned between upper surface of said clutch -adjust- 'fing 'nut 34 and the lower isurface of said shoulder 36 for normally `biasing said members apart. A thin walled lead guide tube 38 is mounted within the clutch 4 and lead vfst-.lector 15 'for preventing lead from adhering to the teeth 24 of the jaws 23. If desired, the tube 38 may be formed integral with the lead iselector 15 as vshown in FIG. 9.

A lead stop 39 is provided in the longitudinal -slot 27 in the A-clutch 4 Aand extends rearwardly and terminates in a bent portion 40 which abuts against `the'sleeve bear- 'ing 135. The-lead stop 39 has a tip-41 which is 'bent an- `gularlyinwardly toward the geometric axis -42 of the writing instrument and has a sliding edge .43 thereon which s'lides on the bottom 28 of the slot'27 in the clutch 4. The angle between the tip 41 andthe geometric axis 42 is preferably-45 or less. 'Thelead stop 39 is made from thin resilient metal and -the tip is adapted to spring 'automatically into alignment with the lead 25 to prevent .the same from falling out of the opening and to position the amount to which it extends.

'The'magazine'assembly 8 comprises an outer magazine 44 and fan,adjustable magazine insert 45 vhaving an enlarged or inwardly extending wall portion 446 to reduce the internal 'diameter Aand more properly support the lead therein. The enlarged wall portion 46 has a forwaidshoulder 47 adapted to vabutvagainst the top 32 of the.lead Yselector ,15. -The magazine insert 45 also has aforward'edge-IS incontactingrelation with the sleeve type slide bearing 35, and external threads 49 whichre- ;ceive.internal threadsS on .an outerlead magazine 44.

The outer magazine 44 is provided with prongs 51 which abut against a lower surface 52 on the plug 10 and an indenta-tion 53 forming an eraser receiving chamber 54 at the upper end thereof. An edge 55 is turned over at one point on a helical angle to cut a thread into an eraser 56 as it is initially screwed into the chamber 54. A tube 57 having slots 5S therein frictionally fits over the upper end of the magazine 8 and is provided with an outer bearing surface 59 to properly position the cap 6 on the barrel 5. y

It is believed that the operation of the writing instrument 1 is obvious from the foregoing description. Referring to FIG. l, wherein all parts are shown in their assembled relation, if it is desired to project a piece of lead 25 or change the adjustment of worn projected lead, the cap 6 is pushed downwardly with respect to the barrel 5. In so doing, the cap 6, by reason of its tapered inner surface 60 cooperating with the bearing surface 59 of the tube 57 forces the outer magazine 44 and magazine insert 45 downwardly thereby moving the sleeve bearing 35 downwardly causing the spring 37 to cornpress and the lead stop 39 to move forwardly to the position shown in FIG. 4. In this position, the shoulder 47 is contacting the lead selector 15. Continued downward pressure on the cap 6 moves the lead selector 15 Iand clutch 4 with the clutch adjusting nut 34 downwardly against the force of the clutch spring 33 thereby moving the clutch jaws 23 downwardly into open position as shown in FIG. 5 so that lead 2 5 may freely fall through the enlarged central opening 20 until it is stopped by` the lead stop 39 in the desired extended position.

The pressure on the cap 6 is then released which first causes the clutch jaws 23 to move upwardly and inwardly by reason of the clutch spring 33 to close the ,opening so that the jaw teeth 24 bite into the properly extended lead 25 at the writing tip 14 of the instrument. Thus, the lead is fixed with respect to the clutch 4. Con- ,tinued release of the pressure on the cap 6 causes the spring 37 to force the projecting mechanism and the cap r6 upwardly and movethe lead stop 39 upwardly to its retracted position as shown in FIG. l. At the Asame time and due to the same force the magazine 8 and the magazine insert 45 move upwardly and the shoulder'47 moves out of contact with the lead selector 15.

Referring to FIG. l, it is seen that the radial pressure on the clutch jaws 23 can be varied by rotating the clutch adjusting nut 34 to increase or decrease the pressure on the clutch spring 33. Moving the nut 34 toward the `clutch closing tube 13 compresses the spring 33 and mov- `ing the nut 34 upwardly releases the spring 33.

To adjust or vary the distance which the lead stop 39 lextends beyond the tip 14, the outer magazine 44 is rotated in relation to the magazine insert 45 thereby moving the magazine insert 45 upwardly .or downwardly to change the position of sleeve bearing 35 with respect to the writing tip. However, this does not change the distance D between the shoulder 47 'and the top of the lead selector. The bearing 35 is initially positioned out ,of contact-with the enlarged head 30.of the lead selector 15 to allow adjustment in either direction. If the magazine insert 45 is screwed into the outer magazine 44, the lead stop 39 moves upwardly or to a more rearwardly positionandcannot be extended as far from the writing tip l14.

The barrel 5 is short, as best seen in FIG. 12, so that in erasing the operator is able to grasp the magazine itself and not the barrel. This gives a positive erasing action and does not allow the magazine to bob up and down when erasing, as might be the case when the barrel is grasped. The bobbing is due-to the fact that the force of erasing might overcome the force of the spring 37 so as to cause the barrel and magazine to move relative to one another.

FIGS. 13 and 14 show -a lmodified eraser holder 61 in which the upper portion of the youter magazine 44 is provided with internal threads 62 which are adapted to receive the threaded holder 61 of an eraser 64. An annular groove 53 is also provided to form a stop means for the eraser holder 61 as in the form shown in FIG. 13. FIG. 14 shows the eraser 64 and holder 61 in their extended position such as when the eraser is partially worn.

FIGS. 15 and 16 are end views of a pair of modified clutch jaws 64 having a substantially square opening 65 formed by reason of each jaw 64 having a V-notch 66 therein whose sides are perpendicular to each other. FIG. 15 shows the jaws 64 open for receiving a relatively thick piece of lead 67, whereas FIG. 16 shows these same jaws 64 closer together for grasping a relatively thin piece of lead 68. In this arrangement, only two jaws are provided.

FIGS. 17 and 18 show a modified magazine 8a having guide means 69 therein which contain a large number of individual pieces of lead in a substantially upright position. Mechanical pencils of the repeater type (that is, where one lead after another is automatically fed from the magazine to the writing opening upon actuation of a button or cap at the upper end of the pencil) have in the past had an inherent disadvantage: in order for the lead to drop through the relatively small central hole 31 in the lead selector 15, the lead must stand substantially upright. This requires the magazine to have a small diameter to prevent the lead, especially small or broken pieces, from assuming steep angles as shown in FIG. 19.

Because of this, magazines of present repeater type pencils have a small inside diameter of between about 1A; inch to Li/32 inch if 0.036 inch diameter lead is used and about 5&2 to 716 inch inside diameter if 0.046 inch diameter lead is used. Because of this, it was recommended to insert only about six to eight pieces of lead into the magazine so that they would not be too tightly compacted and would be free to fall through the relatively small central opening. However, when few pieces were positioned in a magazine as recommended, the lead was free to assume the position shown in FIG. 19.

In my present construction, the magazine 8 may be provided with an enlarged wall section 46 to properly position the lead, or as shown in FIGS. 17 and 18, may be provided with what might be termed a spiral guide member 70 lixedly or loosely positioned in the magazine 8a. This properly positions the lead and increases the capacity so that several dozen pieces of lead, even as many as forty or more, may be placed in the magazine 8a and fed in a guided manner to the small central opening 31 in the lead selector 15.

As shown by the arrow L in FIG. 18, the lead moves spirally inwardly until it reaches the center opening 31. The counter-clockwise arrow T shown on the outside of the magazine 3a in FIG. 18 represents the normal direction of twist or rotation by a righthanded person when bringing a sharper point to bear on the paper. It has been found that persons who write with their right hand usually rotate a pencil counter-clockwise when changing the position of the lead. This normal tendency determines the direction of the spiral guide means 70 and automatically causes the lead to move from the outer chamber 71 to the intermediate chamber 72 to the inner chamber 73 from which it enters the opening 31. Another inuence which causes the lead to automatically move spirally inwardly is the conical surface 32 on the lead selector 15 which forms the bottom of the magazine. This surface 32 is higher at the outside than at the central portion so that the leads move downwardly by gravity as they move inwardly.

Projections 74 are struck from the wall of the magazine to act in the same manner as the forward shoulder 47 of the enlarged wall section 46 to move the lead selector 15 when actuating the mechanism. The projections 74 are better seen in FIG. 19 wherein the spiral guide means 7 0 has been omitted for clarity and to show improper positions which pieces of lead may otherwise assume if guide means are not provided.

This invention is intended to cover all changes and modifications of the examples of the invention herein chosen for purposes of the disclosure, which do not constitute departures from the spirit and scope of the invention.

What I claim is:

1. In a writing instrument, a unitary self-contained writing assembly comprising a lead selector and a clutch connected thereto at all times, said assembly having an opening therethrough for receiving lead, said clutch having jaws thereon with outer inclined surfaces, a clutch closing tube circumscribing said said clutch jaws at said inclined surfaces, a member connected to the upper portion of said clutch, a clutch closing spring positioned between said member and said clutch closing tube for biasing the Y latter against said inclined surfaces, said lead selector having a head thereon, a bearing slidably mounted on said lead selector beneath said head, a lead stop extending longitudinally over a major portion of said writing assembly, said lead stop having an upper end portion terminating at said bearing and a lower end portion positioned in a slot in one of said jaws, a lead stop spring positioned between said member and the head for biasing the upper end of the lead stop upwardly, said springs contacting opposite sides of said member, said lower end portion being adapted to extend downwardly in spaced axial alignment beyond the bottom of said opening in said clutch thereby compressing said lead stop spring.

2. In a writing instrument, a unitary self-contained writing assembly comprising a lead selector and a clutch connected thereto at all times, said assembly having an opening extending therethrough for receiving lead, said clutch having jaws thereon with outer inclined surfaces, a clutch closing tube circumscribing said clutch jaws at said inclined surfaces, a member connected to the upper portion of said clutch, a clutch closing spring positioned between said member and said clutch closing tube for biasing the latter against said inclined surfaces, said lead selector having a head in the upper portion thereof, a bearing slidably mounted on said lead selector beneath said head, a lead stop extending longitudinally over a major portion of said writing assembly, said lead stop having a bent upper end portion contacting said bearing and a lower end portion positioned in a slot in one of said jaws, a lead stop spring positioned between said member and the bent upper end portion for normally biasing the lead stop upwardly, said springs contacting opposite sides of said member, said lower end portion being adapted to extend downwardly in spaced axial alignment beyond the bottom of said opening in said clutch.

3. In a writing instrument, a self-contained writing assembly comprising a lead selector and a clutch connected therebelow, said lead selector and said clutch having an opening extending entirely therethrough, said clutch having jaws therein with outer inclined surfaces, a clutch closing tube circumscribing said clutch jaws at said inclined surfaces, clutch adjustment means mounted on said clutch, a clutch closing spring positioned between said clutch adjustment means and said clutch closing tube for biasing the latter against said inclined surfaces to move said jaws inwardly and close said opening, said lead selector having a head thereon, a bearing slidably mounted on said lead selector beneath said head, a lead stop spring positioned between said clutch adjustment means and said bearing for biasing said bearing toward said head, a lead stop extending longitudinally over a major portion of said writing assembly, said lead stop positioned within a slot in one of said clutch jaws and having an end portion contacting said bearing and being biased upwardly by said lead stop spring, said lead stop having a lower tip normally positioned within the slot in said jaws and adapted to extend downwardly therebeyond in spaced axial align- 1,908,386 ment with .the Opening ,in said lutch means. 2,726,637 2,854,950 References Cited in the file o f this patent UNITED sTAjrEs PATENTS 6 321,785 Bewan; J1 11y 7,1885 8171697 1,779,54 man V.; 1- 00118, 1930 174,949

Wahl I May 9, 1933 Miller Dec. 13, 1955 Johnson" T.- Oct. 7, 1958 FOREIGN PATENTS Germany Aug. 30, 1951 Great Britain Apr. 26, 1923

Claims (1)

1. IN A WRITING INSTRUMENT, A UNITARY SELF-CONTAINED WRITING ASSEMBLY COMPRISING A LEAD SELECTOR AND A CLUTCH CONNECTED THERETO AT ALL TIMES, SAID ASSEMBLY HAVING AN OPENING THERETHROUGH FOR RECEIVING LEAD, SAID CLUTCH HAVING JAWS THEREON WITH OUTER INCLINED SURFACES, A CLUTCH CLOSING TUBE CIRCUMSCRIBING SAID SAID CLUTCH JAWS AT SAID INCLINED SURFACES, A MEMBER CONNECTED TO THE UPPER PORTION OF SAID CLUTCH, A CLUTCH CLOSING SPRING POSITIONED BETWEEN SAID MEMBER AND SAID CLUTCH CLOSING TUBE FOR BIASING THE LATTER AGAINST SAID INCLINED SURFACES, SAID LEAD SELECTOR HAVING A HEAD THEREON, A BEARING SLIDABLY MOUNTED ON SAID LEAD SELECTOR BENEATH SAID HEAD, A LEAD STOP EXTENDING LONGITUDINALLY OVER A MAJOR PORTION OF SAID WRITING ASSEMBLY, SAID LEAD STOP HAVING AN UPPER END PORTION TERMINATING AT SAID BEARING AND A LOWER END PORTION POSITIONED IN A SLOT IN ONE OF SAID JAWS, A LEAD STOP SPRING POSITIONED BETWEEN SAID MEMBER AND THE HEAD FOR BIASING THE UPPER END OF THE LEAD STOP UPWARDLY, SAID SPRINGS CONTACTING OPPOSITE SIDES OF SAID MEMBER, SAID LOWER END PORTION BEING

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