US3771882A

US3771882A - Disposable mechanical pencil assembly

Info

Publication number: US3771882A
Application number: US00257357A
Authority: US
Inventors: M Kapilow
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-05-26
Filing date: 1972-05-26
Publication date: 1973-11-13
Anticipated expiration: 1990-11-13
Also published as: DE2326903A1; FR2189216B1; FR2189216A1; JPS5118851B2; JPS4986120A

Abstract

A disposable mechanical pencil includes a tubular barrel having a forward tapered end through which the lead is adapted to project. A tube which receives this lead is disposed interiorly of the barrel in concentric relation therewith. Outwardly flared arms on this tube cooperate in centering the tube within the barrel. A carrier acts to shift the lead forwardly out of the barrel and includes a laterally projecting finger graspable handle for such purpose. The handle is adapted to move through aligned slots in both the barrel and the tube and also serves as an indicator for the amount of lead remaining within the tube. The barrel includes a radially inwardly projecting lip at the tapered forward end for engaging the lead and preventing it from falling out of the tube. The carrier is provided with resistance means in the form of alternate bends which engage the interior surfaces of the tube thereby preventing the lead from being pushed back into the tube under normal writing pressure.

Description

United States Patent [191 Kapilow Nov. 13, 1973 1 DISPOSABLE MECHANICAL PENClL ASSEMBLY [76] Inventor: Marvin Kapilow, 8 Sound Rd., Rye,

22 Filed: May 26,1972

211 Appl.No.:257,357

Primary ExaminerLawrence Charles Attorney- David S. Kane et al.

[57] ABSTRACT A disposable mechanical pencil includes a tubular barrel having a forward tapered end through which the lead is adapted to project/A tube which receives this lead is disposed interiorly of the barrel in concentric relation therewith. Outwardly flared arms on this tube cooperate in centering the tube within the barrel. A carrier acts to shift the lead forwardly out of the barrel and includes a laterally projecting finger graspable handle for such purpose. The handle is adapted to move through aligned slots in both the barrel and the tube and also serves as an indicator for the amount of lead remaining within the tube. The barrel includes a radially inwardly projecting lip at the tapered forward end for engaging the lead and preventing it from falling out of the tube. The carrier is provided with resistance means in the form of alternate bends which engage the interior surfaces of the tube thereby preventing the lead from being pushed back into the tube under normal writing pressure.

11 Claims, 9 Drawing Figures I DISPOSABLE MECHANICAL PENCIL ASSEMBLY BACKGROUND OF THE INVENTION Over the years, conventional wooden pencils have represented the major portion of the pencil market whereas mechanical pencils have only a minor portion of this market. Several factors have contributed to this share of the market, notably the relative expense of mechanical pencils and the fact that their high cost has rendered them nondisposable. There is also the disadvantage of having to refill the pencil with lead, not to mention, the inherent problem and frustration of readily losing or misplacing a pencil of this type. The conventional wooden pencil indeed eliminates these drawbacks but nevertheless possesses a number of its own drawbacks including the fact that the entire length of the pencil is not writable and consumable, and of course, sharpening is a major disadvantage.

SUMMARY OF THE INVENTION A principal object of this invention is to adapt the advantages of both the conventional wooden pencil and the non-disposable mechanical pencil and provide a disposable mechanical pencil.

Another object is to provide a pencil of the foregoing type with means associated therewith for indicating the amount of lead remaining in the pencil.

A further object is to provide a pencil of the foregoing type employing only three parts excluding the lead and erasure.

Still another object is to provide a pencil of the foregoing type which incorporates effective, inexpensive carrier means for generating sufficient resistance to prevent the lead from being pushed back into the pencil under normal writing pressure while permitting its retraction when such pressures are exceeded or when the pencil is not in use.

A still further object is to provide a pencil of the foregoing type in which almost all of the lead is adapted to be consumed.

An important object is to provide a pencil of the foregoing type with means for providing sufficient frictional force to keep the lead from falling out of the pencil thereby facilitating the use of lead that may be broken along its length.

Other objects and advantages will become apparent from the following detailed description which is to be taken in conjunction with the accompanying drawing illustrating a somewhat preferred embodiment of the invention.

BRIEF DESCRIPTION OF DRAWING In the drawing, FIG. 1 is an elevational view of a mechanical pencil assembly in accordance with the present invention;

FIG. 2 is an enlarged fragmentary longitudinal sectional view taken along line 2-2 of FIG. 1 showing the interior and operating mechanism of the assembly;

FIG. 3 is a fragmentary longitudinal sectional view taken along line 3-3 of FIG. 2;

FIG. 4 is a further enlarged cross-sectional view taken along 4-4 of FIG. 3; 7

FIG. 5 is an enlarged fragmentary section view of the forward tip of the pencil barrel.

FIG. 6 is a cross-sectional view taken along line 66 of FIG. 2;

with mounted carrier being assembled in the rear end.

of the barrel; and

FIG. 9 is a cross-sectional view taken long line 9-9 of FIG. 8.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT The illustrated mechanical pencil assembly 10 includes an outer barrel or shell 12 having a rear open end 14 defined also by raised projection 15 and a tapered forward end 16 terminating in the reduced opening 18 which is of uniform diameter slightly larger than the employed lead to prevent the lead from wobbling when most of the lead has already been consumed. In this connection only line contact of the lead at the forward end could under these circumstances result in lead wobbling. The barrel may be fabricated of low cost material and in a successful application of the invention, it has been molded of polystyrene. A conventional eraser 20 may be disposed in the rear open end 14. The forward reduced opening 18 includes a radially inwardly extending lip 22 which frictionally engages the lead 24 of the pencil assembly to prevent the lead from unintentionally falling out; and in effect renders the pencil drop proof in that should the lead break the pencil remains operational. The reduced tapered end 16 of the pencil includes three equally spaced recesses 26 formed from the male die of the mold which is provided with corresponding outwardly projecting ribs. These ribs mate with surfaces of the female die to take weight off the tip of the male die. In this manner, damage or breaking of the male die is significantly reduced. The barrel 12 is also provided with a longitudinally extending slot 28, the purpose of which will be discussed in detail shortly. This slot 28 extends into aligned recess 29 in raised projection 15.

The lead 24 is supported interiorly of the barrel 12 by tube 30. This tube 30 is provided with a longitudinally extending slot 32 aligned with slot 28 in the barrel 12. The forward end 34 of the tube 30 is centered to properly align the lead 24 in the'opening 18 by the inner surface 36. The back end of the tube 30 is centered interiorly of the barrel 12 by a pair of bifurcated or laterally projecting arms 38. In a successful application of the present invention, the tube 30 was formed of metal and consequently the arms 38 possessed a sufficient degree of flexiblity and resiliency to facilitate its mounting within the interior of the barrel 12 and maintenance of the tube 30 coaxially in relation thereto. Towards the end, the arms provide four corners of contact which bite" into interior walls of barrel 12 to prevent the tube 30 from being retracted.

A carrier 40 is employed to push the lead 24 out through the opening 18 for writing purposes. Towards this end, carrier 40 includes a forward end 42 in engagement with the rear end of the lead 24. The carrier 40 which may be metal also includes a portion 44 having alternate bends, the apices of which engage with the internal surfaces of the tube 30 in providing sufficient frictional resistance to prevent the lead from being pushed back into the tube 30 through the opening 18 under ordinary writing pressure which may range from 0.250 1.250 lbs. of force. In the event normal writing pressure is exceeded and to minimize breakage of the lead tip the frictional resistance of the carrier is overcome and the lead will retract with the carrier. The rear end of the carrier 40 includes an arm or handle 46 which projects laterally through the slot 32 of the tube 30 and the slot 28 of the barrel 12. This handle may be grasped or engaged by a finger to urge the carrier 40 forwardly and consequently the lead 24 out through the opening 18. As will be appreciated, theposition of the handle 46 is also an indication of the amount of lead present in the tube 30. When the carrier 40 has been pushed to its forwardmost position, approximately .150 inches of lead remained unused in a successful embodiment of the invention which was the length of opening 18. Furthermore, the forward carrier portion 44 is sufficiently long to not only permit this substantially complete consumation of the lead but to enable the forward end of slot 28 and to be moved rearwardly so that it will not be in the zone of the barrel 12 that is ordinarily grasped by the fingers when writing. Similarly, the handle 46 will not be in this zone when the lead is nearly all consumed.

The rear of the barrel 12 also includes a pocket clip 48 which is most advantageously molded integrally on the barrel 12. It will be noted that clip 48 does not include any undercuts and possesses a configuration predominantly of straight lines. As a result, a cam operated split mold is not necessary for molding and consequently a parting line is not present. In addition, it has been found that by controlling the shrinkage of the clip 48, and particularly its thicker base, the clips free end will shift closer to the outer surface of barrel 12.

The invention also contemplates cooperating structure which permits self aligning of the assembled tube 30 and carrier 40 in the barrel 12. In this connection, the assembled tube 30 and carrier 40 are inserted into the open rear end 14 as shown in FIGS. 8 and 9. The outer terminal end of handle 46 rides in the recess 29 and upon further insertion eventually passes into and projects out of aligned slot 28. In order to facilitate this self alignment, the distance x from the end of handle 46 to the distal side of tube 30 is approximately equal to or very slightly less than the sum of internal diameter of the barrel l2 and depth of slot 29.

Thus, the lead 24 is consumed and the handle 46 is urged forwardly to expose more lead. The user need only retract carrier 40 and then push lead 24 back into barrel 12 when the pencil is not used or when carried in a pocket. This preserves the lead tip and prevents it from being accidentally broken. Also, the inside of the pocket will not be marked or damaged by the exposed lead tip. When the lead 24 is fully expended, the user need only discard the entire assembly 10 because of this relatively low cost and need only acquire another pencil with a full length of lead 24. In this connection, it has been found that considerably more writing time is provided by the pencil of this invention when compared with a wooden pencil because essentially all of the lead is used, whereas this is not so with a wooden pencil because lead is wasted through repeated sharpenings and when this pencil becomes too short, it is discarded.

Thus, the several aforenoted objects and advantages are most effectively attained. Although a single, somewhat preferred embodiment of the invention has been disclosed and described in detail herein, it should be understood that this invention is in no sense limited thereby and its scope is to be determined by that of the appended claims.

What is claimed is:

1. A disposable mechanical pencil assembly comprismg:

a onepiece integral plastic tubular barrel having a rear end and a tapered forward end having a re duced opening through which writing lead is adapted to project;

a tube for receiving the lead disposed concentrically within the barrel, the forward end of the tube being centered by the taper of the forward end, and centering means centering the rear end of the tube within the barrel;

means for cooperating with the forward part of the lead for retaining the lead in the tube; and

a carrier slidably disposed in the tube for forcing the lead forwardly out through the forward opening of the barrel whereby all the lead in the tube can be consumed and resistance means formed by surfces of the carrier and internal surfaces of the tube for preventing retraction of the lead under ordinary writing pressure the resistance means including at least one alternate bend for frictional engagement with the associated interior faces of the tube, the carrier including a manually graspable handle projecting outwardly through the barrel and serving as an indicator of the amount of lead in the tube, and both the barrel and the tube are provided with aligned slots through which the handle is adapted to travel.

2. The invention in accordance with claim 1 wherein a radially inwardly projecting lip is at the tapered forward end of the barrel for cooperating in retaining the lead in the tube.

3. The invention in accordance with claim 1 wherein the reduced opening includes a substantially cylindrical portion of predetermined length for minimizing wobbling of the lead when only a relatively small part thereof is not consumed.

4. The invention in accordance with claim 1 wherein the rear end of the tube includes an outwardly flared portion for yieldably engaging the adjacent interior surfaces of the barrel.

5. The invention in accordance with claim 1 wherein the outwardly flared portion comprises a pair of arms providing four corner engagement with the interior surfaces of the barrel.

6. The invention in accordance with claim 1 wherein a pocket clip is integrally molded as part of the barrel and the clip is defined primarily by straight line construction and the entire barrel with clip is free from any parting line formed by a split mold.

7. The invention in accordance with claim 1 wherein the tube and carrier are metal.

8. The invention in accordance with claim 1 wherein the carrier is of predetermined length so that the forward end of the slot of the barrel and consequently the handle are rearwardly of the zone of the barrel normally grasped by the fingers of the user during writing while permitting substantially a major portion of the lead to be consumed.

9. The invention in accordance with claim 1 wherein the tapered forward end includes spaced slots caused by a pin of a male mold engaging surfaces of a female mold to prevent breakage of the pin during molding.

10. A disposable mechanical pencil assembly comprising: a tubular barrel having a rear end and a tapered forward end having a reduced opening through which writing lead is adapted to project;

a carrier slidably disposed in the tube for forcing the lead forwardly out through the forward opening of the barrel whereby all of the lead in the tube can be consumed and resistance means formed by surfrom the tip of the handle to the distal side of the tube. l

Claims

1. A disposable mechanical pencil assembly comprising: a one-piece integral plastic tubular barrel having a rear end and a tapered forward end having a reduced opening through which writing lead is adapted to project; a tube for receiving the lead disposed concentrically within the barrel, the forward end of the tube being centered by the taper of the forward end, and centering means centering the rear end of the tube within the baRrel; means for cooperating with the forward part of the lead for retaining the lead in the tube; and a carrier slidably disposed in the tube for forcing the lead forwardly out through the forward opening of the barrel whereby all the lead in the tube can be consumed and resistance means formed by surfces of the carrier and internal surfaces of the tube for preventing retraction of the lead under ordinary writing pressure the resistance means including at least one alternate bend for frictional engagement with the associated interior faces of the tube, the carrier including a manually graspable handle projecting outwardly through the barrel and serving as an indicator of the amount of lead in the tube, and both the barrel and the tube are provided with aligned slots through which the handle is adapted to travel.

10. A disposable mechanical pencil assembly comprising: a tubular barrel having a rear end and a tapered forward end having a reduced opening through which writing lead is adapted to project; a tube for receiving the lead disposed concentrically within the barrel, the forward end of the tube being centered by the taper of the forward end, and centering means centering the rear end of the tube within the barrel; a carrier slidably disposed in the tube for forcing the lead forwardly out through the forward opening of the barrel whereby all of the lead in the tube can be consumed and resistance means formed by surfaces of the carrier and tube for preventing retraction of the lead under ordinary writing pressure; and the rear end of the barrel including an outer projection having an inner recess which is aligned and communicates with the slot of the barrel, said recess cooperating in self aligning the tube and associated carrier when these parts are assembled.

11. The invention in accordance with claim 10 wherein the internal diameter of the barrel plus the depth of the recess approximately equals the distance from the tip of the handle to the distal side of the tube.