JP5078146B2 - Swing-out mechanical pencil - Google Patents

Description

  The present invention relates to a swing-out mechanical pencil that greatly improves the durability of a chuck used for feeding a lead by shaking.

2. Description of the Related Art Conventionally, a mechanical pencil chuck in which electroless plating is formed on the entire surface including a core holding portion of the chuck is known. (See Patent Document 1)
There is also known a mechanical pencil chuck in which a hard film by vapor phase plating is provided on at least a core holding portion of the chuck. (See Patent Document 2)
Furthermore, a knock type mechanical pencil in which molybdenum disulfide is applied to the chuck is known. (See Patent Document 3)
Japanese Utility Model Publication No. 5-82587 JP-A-5-301493 Japanese Utility Model Publication No.3-3435

  A conventional chuck formed with electroless plating or vapor phase plating or a chuck coated with molybdenum disulfide was not used for a swing-out mechanical pencil.

  In addition, the biggest cause of the loss of the chucking force for holding the lead is that the frictional resistance increases due to wear of the chuck and the fastener. Therefore, the rapid movement is small, and the cause of wear of the chuck and fastener occurs when the chuck is pressed against the fastener by a chuck spring stretched with a load of about 500 g. Therefore, the knock type mechanical pencil had relatively little wear.

  However, in the case of the swing-out mechanical pencil, the chuck is moved forward by the impact when the weight is brought into contact with the connector or the core tank, so that the chuck fitted in the fastener moves rapidly and comes off. There was a problem that the friction at the contact portion of the tool was very strong and the wear increased. In addition, unlike a normal knock-type mechanical pencil, in the case of a swing-out mechanical pencil, the chuck must be advanced by the inertial force of the heavy body, so that the load at the time of mounting the chuck spring is set weak. Therefore, the core cannot be held only when the frictional resistance between the chuck and the fastener is slightly increased.

  An object of the present invention is to provide an oscillating mechanical pencil that solves the above problems.

The present invention urges the chuck rearward in the longitudinal direction by a chuck spring stretched with a load of 200 g or less, holds the core by closing the chuck pressed by a fastener, and removes the chuck from a heavy body. This is a swing-out type mechanical pencil that moves forward by the inertial force of the chuck and feeds the lead. The elastic piece of the chuck has a thickness of 0.15 mm to 0.23 mm and a thickness / length of 0.015 to 0. .038 constructed below, thereby forming an electroless plating on at least the head surface of the chuck, the first aspect over the coated molybdenum disulfide thereon.

Further, the chuck is urged rearward in the longitudinal direction by a chuck spring stretched with a load of 200 g or less, and the chuck is closed by being pressed by the fastener, and the chuck is also used for inertia of the weight body. A swing-out type mechanical pencil that is advanced by force to feed out the core, wherein the chuck elastic piece has a thickness of 0.15 mm to 0.23 mm and a thickness / length of 0.015 to 0.038. configure below, to form a vapor phase plating on at least the head surface of the chuck, the second aspect over the coated molybdenum disulfide thereon.

  In the first aspect of the invention, by forming electroless plating on the chuck head surface, the surface hardness of the chuck can be increased and the wear resistance can be improved. In addition, by applying molybdenum disulfide on the electroless plating, it is possible to prevent the fastener from being damaged by hard burrs generated by the electroless plating. Furthermore, even if the chuck fitted in the fastener moves suddenly and is rubbed strongly by the weight body, the chuck wear can be prevented by the synergistic effect of electroless plating and molybdenum disulfide, so the chuck can be moved backward with a weak load. The core can be reliably held even when biased.

  According to the second aspect of the present invention, the surface hardness of the chuck can be increased and the wear resistance can be improved by forming vapor-phase plating on the chuck head surface. Further, by applying molybdenum disulfide on the gas phase plated, it is possible to prevent the fastener from being damaged by a hard burr generated by the vapor phase plating. Furthermore, even if the chuck fitted in the fastener moves suddenly and is rubbed strongly by the weight body, the chuck wear can be prevented by the synergistic effect of vapor phase plating and molybdenum disulfide, so the chuck can be moved backward with a weak load. The core can be reliably held even when biased.

Further, the invention according to claim 1 and claim 2 is that the elastic piece of the chuck has a thickness of 0.15 mm to 0.23 mm and a thickness / length of 0.015 to 0.038. By configuring, a swing-out type mechanical pencil that can hold the core with a strong force even when the chuck is pressed against the fastener with a weak load becomes possible.

  Due to the impact of the heavy body, we realized a swing-out mechanical pencil that prevents the chuck from being worn even if the chuck fitted in the fastener moves suddenly and comes off the fastener.

  Hereinafter, based on FIG. 1 and FIG. 2, the swing-out type mechanical pencil of Example 1 in this invention is demonstrated. Moreover, let the left side of FIG. 1 be the front, and let the right side be back. First, the front part of the brass chuck 1 is divided into three parts, and a head 1A and an elastic piece 1B that can be bent are formed. Further, a taper portion having a smaller diameter as it goes rearward is formed in the head 1A. The elastic piece 1B has a wall thickness L1 of 0.2 mm and a length L2 of 7.0 mm. Furthermore, irregularities are formed on the core holding portion 1C of the chuck 1 with screws or the like. Electroless plating 2 is formed on at least the core holding portion 1C and the head 1A surface, preferably the entire surface, of the chuck 1. As the electroless plating 2, nickel-phosphorus plating having a thickness of about 3 μm is preferable because it has good adhesion and high hardness, and sufficient wear resistance can be obtained. Further, molybdenum disulfide is applied to the surface of the chuck 1 to form.

  A synthetic resin connector 3 is press-fitted and fixed to the rear portion of the chuck 1. Further, a fastener 4 is fitted on the head 1A of the chuck 1, and a chuck spring 6 is stretched between a washer 5 that receives the fastener 4 and the front end of the connector 3 with a load of about 100 g. Therefore, the head 1 </ b> A of the chuck 1 that is normally urged rearward by the chuck spring 6 holds the core 7 by being pressed and closed by the fastener 4. Further, a core tank 8 made of a synthetic resin pipe is press-fitted and fixed to the rear portion of the connector 3. A weight body 9 is externally fitted to the outside of the core tank 8 so as to be slidable in the longitudinal direction, and a mechanism part of a swing-out mechanical pencil is configured. The mechanism portion is inserted from the front of the shaft tube 10, and the washer 5 is brought into contact with the front end of the shaft tube 10. Further, the front member 11 is detachably screwed to the front portion of the shaft tube 10, and the washer 5 is held between the inner step 11 </ b> A of the front member 11 and the front end of the shaft tube 10. Further, the tip member 11 has a built-in lead holder 12 that holds the lead 7 lightly, and forms a swing-out mechanical pencil.

  In the case of the first embodiment, since the electroless plating 2 can be formed on the surface of the core holding portion 1C and the head 1A of the chuck 1 in one step, the resistance of the core holding portion 1C and the head 1A can be increased without increasing the cost. Abrasion can be improved.

  In the second embodiment, the front part of the brass chuck 1 is divided into three parts to constitute a head 1A and a flexible elastic piece 1B. Further, a taper portion having a smaller diameter as it goes rearward is formed in the head 1A. The elastic piece 1B has a wall thickness L1 of 0.2 mm and a length L2 of 7.0 mm. Furthermore, irregularities are formed on the core holding portion 1C of the chuck 1 with screws or the like. The chuck 1 is formed by vapor phase plating on at least the core holding portion 1C and the head 1A surface, preferably the entire surface. As this vapor phase plating, a hard film is formed by TiN having a thickness of about 4 μm by ion plating. Further, molybdenum disulfide is applied to the surface of the chuck, and a swing-out mechanical pencil is constructed using this chuck.

  Even in the case of the second embodiment, since the vapor phase plating can be formed on the surface of the core holding portion 1C and the head 1A of the chuck 1 in one process, the wear resistance of the core holding portion 1C and the head 1A is not increased. Can be improved.

  In the above embodiment, the elastic piece 1B of the chuck 1 has a thickness L1 of 0.2 mm and a length L2 of 7.0 mm. This dimension setting sets the load when the chuck spring 6 is mounted to 100 g. Particularly preferred in some cases. However, the thickness L1 of the elastic piece 1B is 0.15 mm so that the core 7 can be securely held when it is urged rearward in the longitudinal direction by the chuck spring 6 with a load of 200 g or less and pressed against the fastener 4. If the thickness L1 / length L2 of the elastic piece 1B is not less than 0.015 and not more than 0.038 and not more than 0.23 mm, the performance of the chuck 1 can be sufficiently obtained.

(Comparative Example 1)
Comparative Example 1 is exactly the same in shape and material as the brass chuck 1 of Example 1, without forming electroless plating or vapor phase plating, and using a chuck coated with molybdenum disulfide. Is configured.

(Comparative Example 2)
Comparative Example 2 has exactly the same shape as the chuck of Comparative Example 1, is made of phosphor bronze, does not form electroless plating or vapor phase plating, and uses a chuck coated with molybdenum disulfide to form a swing-out mechanical pencil. It is a thing.

  In the swing-out type mechanical pencils of Example 1 and Comparative Examples 1 and 2, the lead was fed out by the inertial force of the weight body by repeated shaking, and the chuck force was measured. As a result, the results shown in Table 1 were obtained.

  As described above, the brass chuck of Comparative Example 1 simply coated with molybdenum disulfide has a soft brass and the chucking force is 5N or less after 30,000 times of swinging. It was unbearable.

  In addition, when the electroless plating was not formed on the brass chuck and molybdenum disulfide was not applied, the chuck surface was hardened but the fastener was damaged. When the fastener was damaged, the surface of the fastener was roughened and shavings were generated, and sufficient performance could not be obtained. Specifically, the chucking force became 5N or less after 150,000 swings, and malfunction occurred.

  The phosphor bronze of Comparative Example 2 coated with molybdenum disulfide has a durability of 200,000 times because phosphor bronze is harder than brass, but has poor machinability compared to brass. In addition to high costs, there are drawbacks in that many defective mechanical parts occur.

  However, the swing-out mechanical pencil using the chuck in which molybdenum disulfide is coated on the electroless plating of Example 1 can obtain a chucking force of 20 N or more even in the number of times of swinging 300,000 and has a good operating state. It was found that a high-performance swing-out mechanical pencil was obtained. The reason for this is that when molybdenum disulfide is coated on the electroless plating, the surface of the chuck becomes hard, but the slippage when pressed is good and the fastener is not damaged. For this reason, it is considered that the durability of the chucking force has been dramatically improved.

  In addition, it is assumed that a chucking force mechanical pencil using a chuck in which molybdenum disulfide is applied on vapor phase plating can obtain a chucking force substantially similar to that in the first embodiment.

  It can be applied to a swing-out mechanical pencil that provides a stable chucking force over a long period of time.

It is principal part sectional drawing which shows the swing-out type mechanical pencil of Example 1 of this invention. Example 1 It is sectional drawing which shows the chuck | zipper of FIG. Example 1

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Chuck 1A Chuck 1 head 1B Chuck 1 elastic piece 2 Electroless plating 4 Fastener 6 Chuck spring 7 Core 9 Weight body

Claims (2)

A chuck spring stretched with a load of 200 g or less is urged rearward in the longitudinal direction, the chuck is pressed against the fastener and closed to hold the core, and the chuck is moved by the inertial force of the weight body. A swing-out mechanical pencil that moves forward and feeds the lead, and the chuck elastic piece has a thickness of 0.15 mm to 0.23 mm and a thickness / length of 0.015 to 0.038. configured, drawer-type mechanical pencil as well as forming an electroless plating on at least the head surface of the chuck, characterized by being coated with molybdenum disulfide thereon. A chuck spring stretched with a load of 200 g or less is urged rearward in the longitudinal direction, the chuck is pressed against the fastener and closed to hold the core, and the chuck is moved by the inertial force of the weight body. A swing-out mechanical pencil that moves forward and feeds the lead, and the chuck elastic piece has a thickness of 0.15 mm to 0.23 mm and a thickness / length of 0.015 to 0.038. configured, drawer-type mechanical pencil, characterized in that to form a vapor phase plating on at least the head surface of the chuck was applied molybdenum disulfide thereon.

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