JP3148147U - Pencil extension tool - Google Patents

Abstract

To provide a pencil extension device that can be used economically and comfortably up to a considerably short length of a pencil. A small protrusion is formed on the inner surface of a pipe that is slightly larger than the pencil, and when the pencil is inserted into the pipe, the protrusion bites into the pencil, and the pencil is fixed by the elasticity of the pencil itself. This extension device is easy to manufacture because the pencil is not rattling and has a good feel and can be used until it is considerably shorter. [Selection] Figure 1

Description

  It relates to an extension device that can be used to extend even short pencils.

  Conventional pencil extension devices are shown in FIG. 2 and FIG. 3, and are composed of a metal pipe 5 and a cap 6 with the front end open and the rear end closed. The pencil is loosened and inserted from the tip of the metal pipe 5, and the cap 6 is tightened and fixed at an appropriate length. The metal pipe 5 has a few cuts at the tip, and when the cap 6 is screwed in, the pencil is sandwiched at the tip of the cut to fix the pencil. In this method, it is necessary to make the inner diameter when the cut portion is tightened so that it is exactly the size of the pencil shape, and the metal pipe 5 connected to the cut needs to be tightened. For this reason, the inner diameter of the pipe is larger than the outer diameter of the pencil and is usually about 9.5 mm. Since the outer diameter of the pencil is about 7.75 mm, there is a gap of 1.75 mm. For this reason, the feel of a hand rattling with a pencil is bad at the time of use. In addition, since this method has a cut in the portion where the pencil is fixed, the wobble increases as the pencil becomes shorter, and it cannot be used up to a very short portion.

The utility model (Registration No. 3072935) filed in the past by the inventor is shown in FIG. 4 and is attached to the inner pipe 7 by sliding the outer pipe 8 into a double pipe as the extension device. The nail 9 is pressed against the outer periphery of the pencil so that the pencil is fixed. Use an inner pipe that is slightly larger than the outer diameter of the pencil so that the pencil does not rattle. To extend the pencil part at the tip, move the outer pipe 8 upward, open the nail 9 and pull the tip of the pencil by hand, or use a stick or pencil that is thinner than the rear end of the inner pipe 7. Insert and press. As a result, the pencil moves downward and exerts a force to push the nail 9 outward, so that the nail 9 comes off the pencil and can be pushed out to an appropriate length. Thereafter, when the outer pipe 8 is shifted downward and returned to the original position, the claw 9 bites into the pencil again and fixes the pencil. In this device, the diameter difference between the pipe inner diameter of 8 millimeters and the pencil outer diameter of 7.75 millimeters is 0.25 millimeters. Also, it is enough if the length of the part where the pencil is inserted into the extension device is 1.5 cm, so it is 6.5 cm when using an electric pencil sharpener and 4 cm when using a knife. A pencil can be used, and a pencil can be used 1 to 1.5 cm shorter than the conventional product. However, this device has a problem that the structure is complicated and it takes time to manufacture.

  Although it depends on the size of the hand, pencils are usually difficult to use when they are about 12 centimeters long. It can be used up to about 9 centimeters if you use it. However, since the length of a new pencil is only 17.5 centimeters, half is not used. This shortcoming, which makes it impossible to use when the pencil becomes too short to hold, is compensated for, so that it can be used economically to a considerably short length.

The minimum length that a pencil can be used with the conventional extension device (Figs. 2 and 3) is about 5 centimeters when the electric pencil sharpener is used. Therefore, the total length is up to 7.5 centimeters. When sharpening a pencil with a knife, the length of the portion to be sharpened is about 3 centimeters. In this case, the pencil can be used up to a total of 5.5 centimeters.

In the extension device (FIG. 4) of the present inventor, a pencil can be used up to a length of 6.5 cm when using an electric pencil sharpener and 4 cm when using a knife. In addition, the device of the present invention can use a pencil up to a length of 6.5 centimeters when using an electric pencil sharpener and 4 centimeters when using a knife, as with the extension device (FIG. 4). A pencil can be used 1 to 1.5 centimeters shorter than the conventional product (FIGS. 2 and 3), and the structure is simpler than that of the extension device (FIG. 4), so that it takes less time to manufacture.

  The structure of the present invention according to claim 1 will be described with reference to FIG. For a pencil with a hexagonal cross section, the diameter of the apex portion is usually 7.75 mm, the diameter of the side portion is 7.15 to 7.2 mm, and for a pencil with a circular cross section like a red pencil, the diameter is 7. 75 millimeters. The inner diameter of the pipe 2 is 8 mm, which is 0.25 mm larger than the pencil. A small protrusion is attached to the inner surface of the pipe approximately 1 cm from the tip of the pipe. The distance between the tip of this protrusion and the opposite wall is 7.5 millimeters, which is slightly smaller than the diameter of the pencil. When a pencil is inserted from the tip opening part of this pipe, the protrusion hits and there is a little resistance, but when the force is further pushed in, the outer periphery of the wooden pencil is depressed and the pencil is fixed by the elasticity of the tree. The fixing strength is fixed so that it does not move easily even if writing with the extension device attached.

When writing with the pencil with the extension device of the present invention strongly pressed against the paper, the pencil may move and the pencil may be pushed into the extension device a little, but it does not move under normal use. In addition, it is possible that the groove of the protrusion gradually increases in the axial direction of the outer periphery of the pencil while it is inserted and removed many times to adjust the length of the pencil, and the fixing of the pencil becomes loose. By rotating the pencil slightly in the circumferential direction without moving the projection, the protrusion moves to a new location on the outer periphery of the pencil, and the pencil is fixed. In the present invention, the length of the portion to be inserted into the extension device is required to be about 1.5 centimeters. Therefore, when the electric pencil sharpener is used, the length of the pencil portion at the tip is required to be about 5 centimeters. Pencils can be used up to a length of 5 cm. When cutting a pencil with a knife, the length of the part to be cut may be about 2.5 centimeters. In this case, a pencil can be used up to a total length of 4 centimeters.

The material of the pipe may be a metal such as stainless steel, iron, aluminum, copper, or plastic. Anything can be used as long as it has a slight protrusion inside.

The rear end of the extension device may be occluded or released. If you accidentally insert the pencil too deeply, you can push the pencil by pushing it with another pencil or a thin stick from the rear end by leaving the rear end open.

The method of making the protrusion on the inner surface of the pipe can be made by pinching the pipe with a tool such as pliers and denting the outer periphery of the pipe. By inserting a metal rod with a diameter of 7.5 mm inside the pipe and supporting it, it can be prevented from being dented too much. Another method is to weld or bond an object smaller than the tip opening to the inner surface. Alternatively, there is a method of providing protrusions on the inner surface in advance when manufacturing the pipe.

The position of the protrusion may be anywhere in the part where the pencil enters, but a position of a distance of 0.5 to 2 centimeters from the tip opening is appropriate so that even a pencil as short as possible can be used.

Claim 2 is a device in which an eraser is attached by releasing the rear end of the extension device. An example of the fixing method of the eraser is shown in FIG. 5, FIG. 6, and FIG. A cylindrical eraser 14 is sandwiched between the U-shaped jigs 10 and inserted from the rear end release portion of the pipe 2 of the extension device. The bottom 12 of the U-shaped jig 10 is slightly smaller than the inner diameter of the pipe 2 of the extension tool, the mouth 13 is slightly larger, and the diameter of the cylindrical eraser 14 is slightly larger than the width of the bottom of the U-shaped jig 10. By doing so, the U-shaped jig 10 and the eraser 14 can be firmly fixed together by being inserted into the extension device by the elasticity of the eraser. In addition, there is a heel warp 11 at the tip of the mouth 13 of the U-shaped jig 10, and this portion is not caught too much on the rear end of the extension device when inserted into the extension device. When the eraser 14 is shortened due to use, the U-shaped jig 10 is pulled out from the pipe 2 of the extension device, and the eraser 14 is pulled out from the U-shaped jig 10 by a necessary length, and again together with the U-shaped jig 10. Insert into pipe 2.

  In the present invention, the gap between the pipe of the extension device and the pencil can be made considerably smaller than that of the conventional product, so that there is less shakiness of the pencil. Also, it is sufficient if the length of the insertion part is 1.5 centimeters, and a new pencil with a length of 17.5 centimeters is a minimum of 4 centimeters, that is, less than a quarter of the new pencil. Can be used up to In addition, the structure is simple and does not require much time for manufacturing.

Outline drawing of this product Conventional product outline drawing Conventional product exploded view Outline drawing of conventional product of the inventor U-shaped jig outline drawing State diagram with an eraser sandwiched between U-shaped jigs State diagram with an eraser attached to a pencil extension device

Explanation of symbols

1. Pencil 2. Pipe 3. Protrusion 4. 4. Indentation Metal pipe 6. Cap 7. Inner pipe8. Outer pipe9. Nail 10. U-shaped jig 11. 11. Reversing the spider Bottom 13. Mouth 14. eraser

Claims (2)

  A pipe-shaped extension device is attached to a shortened pencil to extend its life. A protrusion is attached to the inside of the pipe whose inner diameter is slightly larger than the diameter of the pencil, and the pencil is attached to the pipe of the extension device. A pencil extension device in which, when inserted, the protrusion slightly bites into the outer periphery of the pencil and the pencil is fixed by the elasticity of the pencil itself. In the pipe-shaped pencil extension device, the rear end of the pencil extension device is opened, and a U-shaped jig sandwiching a cylindrical eraser is inserted from the rear end release portion, and the elasticity of the eraser and the U-shaped jig A pencil extension instrument that elastically fixes the U-shaped jig and the eraser, and further has a heel warp at the tip of the U-shaped jig mouth.