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Publication numberUS3779652 A
Publication typeGrant
Publication dateDec 18, 1973
Filing dateAug 5, 1971
Priority dateAug 8, 1970
Also published asDE2139589A1
Publication numberUS 3779652 A, US 3779652A, US-A-3779652, US3779652 A, US3779652A
InventorsS Kunitoku
Original AssigneeNishitetsu Sangyo Co Ltd
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Automatic pencil for drawing a line
US 3779652 A
Abstract
An automatic pencil comprises a motor for constantly rotating the lead therein so that its point is automatically sharpened by contact with a writing surface.
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Claims  available in
Description  (OCR text may contain errors)

United States Patent [191 Kunitoku Dec. 118 1973 [5 1 AUTOMATIC PENCIL FOR DRAWING A 2.480,740 8/1949 Johnson 401 50 X LINE 75 Inventor: Sadayoshi Kunitoku, Oshima Arao, FOREIGN PATENTS OR APPUCATIONS ja a 186,432 6/1907 Germany 401/50 1,394,248 2/1965 France 401/195 [73] Assignee: Nishitetsu Sangyo Co., Ltd.,

Fukuoka, Japan Primary ExaminerLawrence Charles [22] Flled' 1971 Attorney-Holcombe, Wetherill & Brisebois [21] App1.No.: 169,369

[30] Foreign Application Priority [5 7] ABSTRACT Aug. 8, 1970 Japan ..45/69553 An automatlc pencll comprises a motor for constantly rotating the lead therein so that its point is automati- CCll. Cally sharpened by Contact with a writing Surface [58] Field of Search 401/50, 91 V 4 Claims, 14 Drawing Figures [56] References Cited UNITED STATES PATENTS 3,514,211 5/1970 Hasimoto et a1 401/91 X AUTOMATIC PENCIL FOR DRAWING A LINE SUMMARY OF THE INVENTION This invention relates to an automatic pencil for drawing a line In conventional automatic pencils, in order to draw a fine line, the tip of the lead must have been sharpened, or flattened like the head of a chisel, or the diameter of the lead must be small. The former two methods, however, have the fault that since the tip of the lead gradually becomes round as it wears away, it is necessary for the lead to be sharpened many times. And the latter method has the fault that thin lead under 0.3mm in diameter is apt to snap and a dark line cannot be drawn, even though it does not require sharpening.

My invention comprises means for drawing a fine clear line without sharpening the lead as long as the lead remains.

This invention will be better understood upon consideration of the following detailed description of six embodiments thereof, with reference to the accompanying drawings, in which:

FIG. 1 is a schematic side view of the tip of the lead, illustrating the theory of the automatic pencil for drawing a line;

FIG. 2 is a vertical section taken along the line II of FIG. 1;

FIG. 3-9 are axial sectional views showing various embodiments of a device for holding a lead or turning it;

FIGS. 10-14 are transverse sections taken along the line 11-11 in FIG. 3, the line Ill-III IN FIG. 4, the line IVIV in FIG. 5, the line V-V in FIG. 7, the line VI-VI in FIG. 9, respectively.

Referring now to FIGS. l-l4, the illustrated embodiments of the automatic pencil for drawing a line according to this invention will now be described.

The automatic pencil in the present invention comprises a rod 2 for advancing a lead in a holder 1, which rod is rotated by a small motor 3 at one end of the pencil, e.g., a micromotor or a micro-airmotor. The lead 5, which is mounted in a chuck 4 at the tip of the rod, rotates with the rod.

In the present invention, if a new lead rotated by the small motor 3, the rod 2, and the chuck 4 is inclined at 30-45, the tip (a) of the lead 5 wears to form a conical shape. The conical-shaped tip (a) of the lead 5 continues to wear away due to abrasion on the paper 6, and the conical shape is maintained until the lead 5 is used up. Then, theoretically, a line having no width ought to be drawn just under the axis of the conical-shaped top of the lead 5 by the base (p-q) of the tip (a) of the lead 5, if the lead 5 is hard and the paper 6 is quite hard and smooth. However since the surface of the paper is uneven, the line has a certain width. Nevertheless, the line is not more than 0.4 mm wide when a lead 2 mm in diameter is used, and the line is not more than 0.2 mm wide in case of a lead 1 mm in diameter. (See FIG. 1 and FIG. 2; t, and t in FIG. 2 represent the width of the lines on the paper 6.)

According to the present invention, when the conical-shaped tip (a) of the rotating lead 5 is moved in one direction, while in contact with the paper 6, a fine dark vantage that a dark line may be drawn with very light pressure of the lead 5 against the paper 6 and, in addition, the width of the line can be freely controlled by pressure of the lead 5 against the paper 6, or the quality of the paper.

Several specific embodiments of the present invention will now be described in detail.

The first embodiment (illustrated in FIGS. I-3 and FIG. 10)

In FIG. 3, a holder 1 consists of two telescopic sec tions, with the left section housing a narrow tube 8 and the right section housing a micromotor 3. When the right casing is pushed to the left the lead 5 is projected from the narrow tube 8 by the rod 2, which is an extension of the drive shaft of the micromotor and carries a chuck 4 holding the inner end of the lead. The microairmotor 3 mounted rotates the rod 2 in the center of the holder 1, thus rotating the lead 5 so that the tip of the lead 5, as shown in FIG. 1, becomes conical with a vertical angle of -90, if the holder is inclined at 3045 and the tip of the lead 5 rotates in contact with the surface of a rough paper e.g. a sand paper, before the lead is actually used. Afterwards, when the base (p-q) of the conical-shaped tip (a) of the lead 5 moves along a ruler 7 in contact with a paper 6, a line of the desired width (2 can be drawn on the paper 6 by contact. The conical-shaped tip (a of the lead 5 is worn away due to its rotation and thus maintains its conical shape. Therefore it is unnecessary for the tip of the lead 5 to be sharpened.

The second embodiment (illustrated in FIG. 4 and FIG. 1 1

In the second embodiment, a micromotor 3 is telescopically and axially inserted in the holder 1. One end of a rod 2 is connected to the drive shaft 9 of the micromotor by a coupling 10, and the end of a lead 5 is seated in a chuck 4 at the other end of the rod 2. In this embodiment, when the micromotor 3 is pushed to the left the lead 5 is projected from the narrow tube 8, since it is pushed out by the rod 2 connected to the micromotor 3.

The third embodiment (illustrated in FIG. 5 and FIG. 12)

In the third embodiment, a micromotor 3 is mounted near one end of a holder 1, a chuck 40 at one end of a rod 2 is located in the narrow tube 8a near the tip of the holder 1, and in this embodiment, the part of a lead 5 is inserted in the rod 12 and is gripped by the chuck 4a. The tube 8a is slidable in the casing 1 against the resistance of the spring. When the narrow tube 8 is pushed to the right, the lead 5 is released by the chuck, which slides inwardly along the lead so that when the tube 8 is again permitted to move to the left, the lead projects therefrom.

The fourth embodiment (illustrated in FIG. 6)

In the fourth embodiment, a push rod 14, one end of which projects from the end of the holder 1, is connected to a micromotor 3 in the holder 1. When the push rod 14 is pushed to the left and the micromotor 3 advances in the direction of the narrow tube 8, the lead 5 is released by the chuck 4b and projects from the narrow tube.

The fifth embodiment (illustrated in FIG. 7 and FIG. 13)

In the fifth embodiment, the end of a rod 2, which has a chuck 4 at one end for holding the lead, is inserted into a first tube 11 in which it is held by the second chuck 12. The end of said tube 11 is connected to the drive shaft 9 of a small motor 3 through a shaft coupling l0, and the end of a lead 5, which projects through a narrow tube 8 gripped by the chuck 4. In this embodiment, when the micromotor is pushed to the left, the rod 2 is released by the second chuck and the lead is pushed by the rod 2 to project it from the narrow tube 8.

The sixth embodiment (illustrated in FIG. 9 and FIG. 14)

In the sixth embodiment a micromotor 3 mounted in a holder 1 is connected to a pressure tube 13 slidably mounted in the end of the holder 1. A rod 2 is connected directly to the drive shaft of the motor, and the end of a lead 5 in the narrow tube 8 is gripped in the chuck 4 at the tip of the rod 2. In this embodiment, when the pressure tube 13 is pushed to the left, the lead 5 is projected through the narrow tube 8 by the rod 2.

The seventh embodiment (illustrated in FIG. 8)

In the seventh embodiment, a micromotor 3 is mounted at the end of a holder 1 and the lead 5 is gripped by a chuck 4 at the end of a rod 2 extending from drive shaft of the micromotor. A narrow tube 8, thepart A, the part B and the part C are fixed to each other. Therefore, when the narrow tube 8 is pulled outwardly, all three of the parts connected to it, A, B, and C move to the left together with it. After that, when the narrow tube 8 is returned to its original position, a desired portion of the lead 5 projects outwardly through the narrow tube 8.

What is claimed is:

1. An automatic pencil for drawing a line comprising a hollow casing having an open end, gripping means rotatbly mounted in said casing in axial alignment with said open end for holding a lead projecting through said open end against transverse movement within said casing, and an electric motor connected to rotate said gripping means and lead, both said motor and gripping means being longitudinally sladable in said casing. slidable 2. An automatic pencil for drawing a line comprising a hollow casing having an open end, gripping means rotatably mounted in said casing in axial alignment with said open end for holding a lead projecting through said open end against transverse movement within said casing, and an electric motor connected to rotate said gripping means and lead, said casing comprising two parts, one of which is slidable with respect to the other, and said motor being fixed to one of said parts.

3 An automatic pencil as claimed in claim 2 in which said gripping means is a spring-operated chuck mounted to be opened when one part of said casing slides toward the other and closed when it slides away from the other.

4. An automatic pencil for drawing a line comprising a hollow casing having an open end, gripping means rotatably mounted in said casing in axial alignment with said open end for holding a lead projecting through said open end against transverse movement within said casing, and an electric motor connected to rotate said gripping means and lead, said motor being mounted to slide in said casing and said gripping means being a spring operated chuck mounted to be opened when said motor slides in one direction from a normal rest position and closed when said motor slides in the other direction and while it remains in said rest position, and said motor carrying abutment means positioned to advance said lead when said motor is moved in said one direction.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2480740 *Apr 8, 1947Aug 30, 1949IbmPencil holder with means to rotate the pencil with respect to the holder incident to use thereof
US3514211 *Mar 12, 1968May 26, 1970Torii OsamuPencil
*DE186432C Title not available
FR1394248A * Title not available
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US5015049 *Nov 23, 1988May 14, 1991Kaiser Optical SystemsMethod of forming holographic optical elements free of secondary fringes
US5208987 *May 12, 1992May 11, 1993Hart Enterprises, Inc.Marking device with vibrating yieldable writing tip
Classifications
U.S. Classification401/50, 401/195, 401/52
International ClassificationB43K21/00, B43K29/06
Cooperative ClassificationB43K21/00, B43K21/006, B43K29/06
European ClassificationB43K21/00G, B43K21/00, B43K29/06