A thermochromic writing instrument with a movable friction part at the pen tip.

Abstract

This thermochromic writing instrument allows for instant switching between the pen tip and friction part with a push button operation, eliminating the need to change your grip when erasing ink. It can be installed in pens that require space inside the barrel, such as three-color pens and multi-function pens, and features a highly durable, stable friction part that allows for easy rubbing, while maintaining a comfortable grip during writing. [Solution] A push button is located on the side of the barrel near where the writer holds it. By pressing this button, the friction part at the tip of the pen can be extended forward beyond the tip of the pen. The pen tip support and the friction part slide together, with the pen tip support also supporting the friction part. The friction part can be retracted by the expansion and contraction of a spring at the rear. A movable cam ensures that the mechanism engages even if the cross-section of the slider is circular. These devices efficiently utilize the space inside the barrel, allowing it to be installed in three-color pens and multi-function pens, and the shape of the barrel does not become too thick, resulting in a thermochromic writing instrument.

Description

Technical Field

[0001] The present invention relates to a thermochromic writing instrument, which has a movable friction part at the pen tip.

Background Art

[0002] Conventional thermochromic writing instruments have a friction part (hereinafter referred to as the friction part) made of a low-wear elastic material that can rub the trace of thermochromic ink at the rear part of the pen as shown in FIG. 12 of Patent Document 1, and thermally discolor the trace with the frictional heat generated at that time. This type requires changing the front and rear parts of the pen and changing the orientation of the pen to erase the trace, which is troublesome.

[0003] There is also one with a friction part at the pen tip as shown in FIG. 1 of Patent Document 1. This also requires storing the pen once to use the friction part at the pen tip, and the operation part at the rear of the pen must be pressed, so it is necessary to change the way of holding the pen, which is troublesome.

[0004] To solve the above problems, there is also one with an operation part at the hand of the writer called side knock as shown in FIG. 9 of Patent Document 1. With this type, it is not necessary to change the way of holding the pen greatly, but it is necessary to separate the finger from the shape of the hand holding the pen and writing, press the operation part with that finger, release it to store the pen, move the finger away from the operation part to the shaft cylinder to erase the trace, press the operation part again after finishing erasing, and when the pen comes out, move the finger from the operation part to the shaft cylinder again to start writing, which requires a series of operations and is troublesome.

[0005] Furthermore, in multi-function pens such as three-color pens, there is play in the barrel's stroke from the rear operating section to the pen tip opening, allowing multiple pens to slide out from the same opening. This mechanism makes it difficult to use a side-knock mechanism at the front. Even if a side-knock mechanism were possible, having multiple operating sections protruding from the writer's hand would negatively impact the writing experience. Additionally, erasing the writing may require retracting the pen, necessitating checking the color before writing again.

[0006] The most similar invention to this one is the thermochromic writing instrument described in Patent Document 2. This pen, like the present invention, uses a push button on the side called a pressing body to push the friction part forward from the pen tip. However, it has the problem of low strength because it consists of a thin rod-shaped device. Although the literature mentions supporting the protruding friction part with the barrel, it is thought that it may shift or that the rubbing motion will be difficult. In addition, there is the problem that the writing can only be rubbed by the friction part at a fixed angle where the friction part protrudes.

[0007] Furthermore, the mechanism that releases the push button to return it to its original position is located in the space in front of the barrel, which also makes it difficult to install in conjunction with a three-color pen or a multi-function pen.

[0008] Furthermore, because the slider has a straight cross-section and the cam that pushes the slider can only move in a straight line, the barrel becomes thicker or the cross-section of the barrel becomes polygonal, causing the writer's hand to feel angular while writing.

[0009] In addition, there are thermochromic writing instruments such as Patent Document 3, which have a sliding friction part that surrounds the pen tip. However, since there is no mechanism to slide it, it must be slid by hand, which would be difficult to operate with one hand, and there is no function to automatically return it with a spring or anything, so it is inconvenient to use.

[0010] Other designs, such as Patent Document 4, involve rotating the operating part to push the friction part forward of the pen tip. However, rotating the operating part while fixing the barrel is difficult to do with one hand. Furthermore, the retractable mechanism requires a large space inside the rear barrel, making it difficult to install in conjunction with a three-color pen or a multi-function pen. [Prior art documents] [Patent Documents]

[0011] [Patent Document 1] Re-tabled publication No. 2008 / 105227 [Patent Document 2] Japanese Patent Publication No. 2019-116061 [Patent Document 3] Japanese Patent Publication No. 2011-230439 [Patent Document 4] Japanese Patent Publication No. 2009-184279 [Overview of the project] [Problems that the invention aims to solve]

[0012] In this invention, "knock" refers to a device whose state changes each time it is pressed and released, while "push button" refers to a device whose state changes when pressed and returns to its original state when released. The operation of a push button in this invention is different from that of a knock. Furthermore, "forward" refers to the direction of the pen tip, and "backward" refers to the opposite direction from the pen tip.

[0013] This invention was made in view of the above-mentioned problems, and provides a thermochromic writing instrument that eliminates the need to change the orientation of the pen when erasing writing with a thermochromic writing instrument, eliminates the troublesome operation of clicking the button several times, can be installed on three-color pens and multi-pens, has high strength and stability without slipping, has a friction part that allows for easy rubbing, and has a shape that is not angular or thick, making it easy for the writer to grip when writing. [Means for solving the problem]

[0014] To achieve the above object, the thermochromic writing instrument of the present invention is provided with a friction portion at the pen tip in a hollow structure surrounding the pen tip, and a push button is provided on the side surface near the shaft cylinder held by the writer. By pushing in the push button, the slider in the shaft cylinder can be slid to project the friction portion at the pen tip forward beyond the pen tip end. The thermochromic writing instrument has the feature that the pen tip support portion and the friction portion slide integrally, and the pen tip support portion also serves as a support for the friction portion.

Effect of the Invention

[0015] Due to the above features, the friction portion protruding beyond the pen tip end can erase the handwriting.

[0016] Also, this friction portion is always pulled back behind the pen tip by a spring. After finishing erasing the handwriting, it can be automatically retracted simply by releasing the pushed-in push button, and the pen tip can return to the state where it protrudes forward.

[0017] This spring and slider can also secure sufficient space in the shaft cylinder with a hollow structure, so they can be installed in the same way even in a three-color pen or a composite pen.

[0018] Also, with a playful cam mechanism and a slider with a circular cross-section, the cross-section of the shaft cylinder in the circumferential direction can be made circular, not polygonal and not too thick.

Brief Explanation of Drawings

[0019] [Figure 1] It is a cross-sectional view of the shaft cylinder of the pen tip of the present invention. [Figure 2] It is a cross-sectional view of the shaft cylinder in a state where the pen tip of the present invention is switched to the friction portion. [Figure 3] It is a cross-sectional view of the shaft cylinder, friction portion, support portion, and slider of the pen tip of the present invention. [Figure 4] It is a schematic view of the push button, cam, and slider of the present invention. [Figure 5] It is a schematic view of the cam and pin inside the push button of the present invention. [Figure 6]This is an explanatory diagram illustrating the finger placement during use of the present invention. [Modes for carrying out the invention]

[0020] This form of thermochromic writing instrument has a barrel (1) that houses a pen (4,5) equipped with thermochromic ink, and a push button (6) on the side of the barrel (1) where the writer holds it when writing. The upper edge of the push button (6) is attached to the barrel (1) by elastic rubber or the like, and the lower part can be pushed inward into the barrel. The pen can be fixed or movable with a push-button mechanism at the rear, as long as the rear of the pen ink portion is supported by the rear of the barrel, either directly or indirectly. A marker or other instrument may also be used instead of a pen.

[0021] The mechanism is designed so that pressing the push button causes a cam (7) located inside the push button to push forward the diagonally cut hollow slider (3) inside the barrel, along with the integrated pen tip support (10) and friction part (2), beyond the pen tip (5). As a result, the friction part (2) protrudes beyond the pen tip (5) (Figure 2), allowing the writing to be erased by friction.

[0022] It is preferable that the inside of the push button (6c) be shaped with a hollowed-out center so as not to interfere with the ink portion (4) of the pen.

[0023] The cam (7) that pushes the slider is attached to the tip of a flexible pin (12) that can be opened and closed, and the pin (12) is fixed to the inside (6c) of the push button by a pin holder (11).

[0024] The pin (12) allows the cam (7) at the tip of the pin, which has some play in the direction of the pin's flex, to engage with the slider (3) even if the cross-sectional shape of the slider (3) is circular. Also, when the slider (3) is pushed or pushed back by the spring (8) (actions such as pressing or releasing the push button), the pin (12) contacts the inside (6c) of the push button, preventing play and allowing force to be transmitted. Alternatively, the cross-section of the pin can be made rectangular, like that of a hairpin, to create directions in which it bends easily and directions in which it does not. In the case of a three-color pen or a multi-pen, it is good to give the pin a curved shape so that when the push button is pressed, the pin surrounds the pen, avoiding it. Alternatively, a cam can be used instead of a pin, as long as it moves to conform to the slider with a circular cross-section, engages with it, and does not collide with the pen.

[0025] The slider (3) should be equipped with a groove (3d) to restrain the trajectory and prevent the cam (7) from coming off.

[0026] The cam (7) will come into contact and rub against not only the slider (3) but also the inside of the shaft cylinder (1c). Therefore, a rounded, slippery shape is preferable for the cam (7).

[0027] The slider (3) is connected to a fixing part (9) which is fixed to the inside (1c) of the barrel by a spring (8), so it is constantly pulled backward, and unless the push button (6) is pressed, it pulls the friction part (2), which is integrated with the slider (3), back behind the pen tip (5).

[0028] The pen support part (10) slides together with the slider (3) and the friction part (2), but the mechanism by which the pen support part (10) is further supported by the barrel (1) allows it to support both the pen tip (5) and the friction part (2). The hollow cylindrical part (10c) of the pen support part (10) that does not support the pen is designed to have a length that takes into account the range of motion of the slide, so that it is always supported by the barrel (1).

[0029] The slider (3) and pen support section (10) have space on the inside (3c, 10c), and the spring (8) also has a wide inner diameter and is designed to conform to the barrel, creating a structure that can accommodate three-color pens and multi-function pens.

[0030] Furthermore, by providing a slope in each vertical cross-section, it becomes easier to guide the pen tip to the front when changing the ink in the pen. [Examples]

[0031] As shown in Figure 6, by pressing the push button (6) with the thumb, sufficient force can be obtained to push out the friction part (2), and the force can be transmitted when rubbing the ink while maintaining the same hand shape. [Examples]

[0032] The structure of this invention can be used in combinations of writing and erasing tools, such as a mechanical pencil and an eraser that produces less eraser residue, or a whiteboard marker and an eraser. [Industrial applicability]

[0033] The present invention provides a thermochromic writing instrument. [Explanation of symbols]

[0034] 1 shaft cylinder 1b Shaft cylinder cross section 1c Inside of shaft cylinder 2 Friction part 2b Cross section of friction part 3 Sliders 3b Slider cross-section 3c Slider inside 3D slider cam restraint groove 4. Pen ink area 5 nibs 6 Push buttons 6c Push button inside 7 Cam 8 springs 9 Fixing part that secures the spring and shaft cylinder 9b Cross-section of the fixing part that secures the spring and shaft cylinder 9c Inside of the fixing part that secures the spring and shaft cylinder 10 Pen support section 11. Fastener for attaching pins to buttons 12 pins 100 Writing state 101 Friction point rubbing A Continues to the pen tip Continues to the rear of the B pen.

Claims

1. A thermochromic writing instrument characterized by having a push button on the side of the barrel where the writer holds it when writing, and by pressing the push button, a cam inside the barrel pushes a slider toward the pen tip, causing the pen support part and friction part, which move in conjunction with the slider, to move ahead of the pen tip, and the slider, pen support part and friction part all have a hollow structure that surrounds the pen tip and pen ink part, and the pen support part is supported by the barrel whether the pen tip or the friction part is protruding due to the slide, in either case.

2. A thermochromic writing instrument as described in claim 1, characterized in that a spring with a wide inner diameter that can surround the pen ink portion is located behind the slider of the thermochromic writing instrument and is positioned along the inside of the barrel, and a hollow fixing part is located behind the spring that is fixed to the barrel, and the spring connects the fixing part and the slider, thereby constantly pulling the slider backward by the compressive force of the spring and retracting the friction part at all times.

3. A thermochromic writing instrument according to claim 1 or 2, wherein the cross-sectional shape of the slider and barrel is circular, the cam that pushes the slider is attached to the tip of a pin installed inside the push button, the cam and slider engage even if the cross-sectional shape of the slider is circular as the pin opens and closes and flexes, and the slider has a groove to restrain the trajectory of the cam at the tip of the pin, making it difficult for the cam to come off, and the thermochromic writing instrument is characterized by being equipped with these devices.

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