JP3262783B1 - Shaft barrel with grip and method of forming the barrel - Google Patents

Abstract

An object of the present invention is to provide a shaft cylinder with a grip that does not impair the appearance of a grip part due to a gate mark or cause a feeling of strangeness when gripping the grip part, and a method of molding the shaft cylinder. SOLUTION: An outer peripheral surface of the grip portion 30 is formed by forming a gate mark 31 on an end surface of the grip portion 30 in a grip-equipped cylindrical tube having a grip portion 30 provided by double molding on the outer periphery of the axial tube body 10. The convex or concave gate mark 31 is not exposed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a barrel with a grip having a grip formed on the outer periphery of the barrel by double molding, and a method of forming the barrel with a grip. It relates to a molding method.

[0002]

2. Description of the Related Art Conventionally, a barrel with a grip is manufactured by separately forming a shaft and a grip and then assembling it, or in a first step, a barrel is first molded by a primary molding die. In two steps, the grip portion is formed by secondary molding on the outer periphery of the barrel using a secondary molding die. In this case, the grip portion is welded to the outer peripheral surface of the barrel. It has the advantage that it does not easily turn or come off.

However, in the above-mentioned conventional barrel with a grip, since the gate in the secondary molding die is located on the outer peripheral surface of the cavity representing the grip portion, the outer peripheral surface of the grip portion has a convex shape. Or, it has a concave gate mark, and the gate mark causes problems such as poor appearance and poor grip feeling when gripping the grip portion. Therefore,
The gate trace may be post-processed by cutting, polishing, or the like, resulting in work complexity and difficulty, and the post-processing has led to an increase in product cost.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and an object thereof is to impair the appearance of a grip portion due to a gate mark or to provide a grip feeling when the grip portion is gripped. An object of the present invention is to provide a shaft cylinder with a grip and a method of forming the shaft cylinder, which does not cause a sense of incongruity.

[0005]

The technical means of the present invention for solving the above-mentioned problems is a double-molded shaft barrel having a grip portion provided on the outer periphery of the barrel body. At the front or rear end
The grip portion is formed so that the material is screwed and connected.
Is an end surface on the side where the connection member to be screwed and connected comes into contact
A gate mark is formed .

According to the above technical means, the gate mark is formed in a convex or concave shape on the end face of the grip portion. Therefore, since no gate mark is formed on the outer peripheral surface of the grip portion, the problem of the appearance and the problem of the grip feeling when the grip portion is gripped can be solved.

Further , by connecting the connecting member to the shaft cylinder body by screw connection, the gate mark can be hidden by the connecting member, and the frictional force between the convex or concave gate mark and the end face of the connecting member can be obtained. In addition, it is possible to prevent the threaded portion between the barrel body and the connection member from being loosened. That is, since the grip portion is welded and integrated with the barrel body by double molding, it does not rotate on the outer peripheral surface of the barrel body. When the connection member is screw-connected to the barrel body, the end surface of the connection member is brought into contact with the end surface of the grip portion, and a convex or concave gate mark formed on the end surface of the grip portion; By the frictional force with the end surface of the shaft member, loosening of the threaded portion between the barrel body and the connection member is prevented. Preferably, as a specific example of the above aspect, the barrel body is a front shaft portion of a writing instrument, the connection member is a rear shaft portion of the writing instrument, and the grip portion is a rear portion to be screw-connected. The gate trace is formed on the rear end surface where the shaft portion comes into contact.

[0008] Further, the method of molding the shaft cylinder with a grip is a molding method in which the grip portion is secondarily molded in a second step on the outer periphery of the shaft cylinder body which has been primarily molded in the first step. An elastic resin material melted in the axial direction is injected from the end into the cavity of the secondary molding die that models the grip portion.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show an example of a shaft cylinder with a grip according to the present invention. Shaft tube A with this grip
Is composed of a main body 10 formed primarily in the first step of the double molding, and a grip portion 30 formed integrally on the outer peripheral surface of the main body 10 in the second step. .

The barrel body 10 is a front shaft portion of a writing instrument,
A tubular connecting member 20 constituting a rear shaft portion of the writing instrument is screwed coaxially to the rear end side. The barrel body 10 is made of polypropylene (PP) or polyamide (P
A) is molded from a hard resin material such as
1 and the connecting member 2
It has a male screw portion 12 that can be screwed into the female screw portion 21 of the “0”.

The grip portion 30 is provided on the outer peripheral surface of the shaft cylinder main body 10 at a position between the front end portion 11 and the female screw portion 21.
It is formed by molding an elastic resin material such as an elastomer resin by double molding, and at this time, a gate mark 31 is formed on the rear end face 30a.

The gate mark 31 is a mark that separates the runner 32 at the time of molding shown in FIG. 5 (c). It has a concave shape.

According to the shaft cylinder A with the grip having the above structure, the connecting member 2 is attached to the male screw portion 12 on the rear end side of the shaft cylinder body 10.
When the female screw part 21 of No. 0 is screwed and connected, the grip part 30
The front end face 20a of the connection member 20 abuts on the rear end face 30a. Therefore, the gate mark 31 is hidden by the front end face 20a of the connection member 20, and does not impair the appearance. At this time, even if the gate trace 31 is formed in a convex shape, the convex gate trace 31 is pushed by the front end surface 20 a of the connecting member 20, so that the rear end surface 3 of the grip portion 30 is formed.
Since it is elastically deformed so as to sink into 0a, the appearance is not impaired.

In the state where the female screw 21 of the connecting member 20 is screwed to the male screw 12 on the rear end side of the barrel body 10 as described above, a convex or concave gate mark 31 forms
The coefficient of friction between the rear end face 30a of the grip portion 30 and the front end face 20a of the connecting member 20 abutting on the rear end face 30a increases. Therefore, the connection member 20 does not easily loosen due to vibration or the like. In particular, when the gate trace 31 is formed in a convex shape, the gate trace 3 protruding in the convex shape is used.
Since 1 is locally pressed into contact with the front end face 20a of the connection member 20, the effect of preventing the connection member 20 from loosening is increased.

Next, a method of forming the shaft cylinder A with the grip will be described in detail. This molding method includes a first step of primary molding the barrel body 10 using the primary molding die 1,
This is a so-called double molding including a second step of secondary molding the grip portion 30 on the outer periphery of the barrel body 10 using the secondary molding die 2.

As shown in FIG. 3A, the primary molding die 1 includes a fixed die 41, a first movable die 42, and a core pin die 4.
3. By combining the core pin supporting mold 44, a first cavity 51 that models the barrel body 10 is formed inside the first cavity 51 from two circumferential positions of the first cavity 51. Ports 52a, 52a for injecting the molten hard resin material into the first runner passage 52 for flowing the molten hard resin material to each gate port 52a.
It consists of:

The first movable mold 42 is a mold movable so as to be divided into two parts in the horizontal direction and opened. One example shown in FIGS. 3 (a) and 3 (b) is a piece of the first movable mold 42. Shows half. That is, one half of the illustrated first movable mold 42 moves in the back direction, and the other half (not shown) moves in the front direction.

In the first step, first, the molten hard resin material is injected into the first cavity 51 from the circumferential direction through the first runner passage 52 (the state shown in FIG. 3B). Then, after the injected hard resin material is cured, the first movable mold 42 moves backward in the drawing together with the core pin mold 43 and the core pin support mold 44 while moving so as to open in two. At this time, the primary molding die 1
Since the runner 13 formed therein is fixedly engaged with the fixed mold 41, the runner 13 is cut at the gate port 52 a and removed from the barrel body 10.

Therefore, as shown in FIG. 3 (c), a preparation mode for the second step with the molded barrel body 10 held on the outer periphery of the core pin mold 43 supported by the core pin support mold 44. It becomes.

Next, the core pin mold 43 holding the barrel body 10 on the outer periphery as described above passes through the first movable molds 42 on the left and right sides by the rotating operation shown in FIG. The process moves between the molds 45 and 45. At this time, the core pin supporting die 44 also moves to the second movable die 45 side by the rotation operation while being integrated with the core pin die 43.

The secondary molding die 2 used in the second step is:
As shown in FIG. 5 (a), this is a mold in which a fixed mold 41 'and a second movable mold 45 are combined. In the mold, the core pin mold in which the primary molded barrel body 10 is held on the outer periphery. By inserting 43, a second cavity 53 simulating the grip portion 30 is formed between the outer periphery of the barrel main body 10 and the second movable mold 45. In addition, a second runner for injecting a molten elastic resin material into the second cavity 53 from the two gate ports 53a, 53a on the core pin supporting mold 44 side is provided in the fixed mold 41 'and the second movable mold 45. A passage 54 is formed.

The second movable die 45 is a die that can be opened so as to be divided into two parts in the horizontal direction similarly to the first movable die 42 described above. One example shown in FIGS. 5A and 5B is as follows. 5 shows one half of the second movable mold 45, and illustrates the second movable mold 4 shown in FIG.
5 is movable in the depth direction, and the other half (not shown) is movable in the front direction.

In the second step, first, the molten elastic resin material is injected into the second cavity 53 from the axial direction through the second runner passage 54 (the state shown in FIG. 5B).
Next, after the injected elastic resin material is cured, the second movable mold 4
The core pin type 4 is movable while being opened in two parts.
3 and the core pin supporting die 44 are movable back to the right in the figure. Then, as shown in FIG. 5C, the grip portion 30 formed on the outer periphery of the shaft cylinder main body 10 is held on the outer periphery of the core pin mold 43 with the runner 32 after the die cut.

The shaft cylinder A with the grip formed with the runner 32 attached thereto is moved backward (moves rightward in FIG. 5) with respect to the core pin support die 44 so that the core pin support die 44 is moved. And the mold is removed from the core pin mold 43. And the runner 32
Is separated from the grip portion 30 in the operation of the next step, and at this time, a convex or concave gate mark 31 is formed on the rear end surface 30a of the grip portion 30. As described above, the gate mark 31 does not impair the appearance of the grip portion 30 and acts as a stopper for the connection member 20 when the connection member 20 is screwed and connected. Even if it is done, it is not necessary to remove it by polishing or the like.

Although the above embodiment is an example in which a gate mark is formed on the rear end surface of the grip portion, a gate mark may be formed on the front end surface of the grip portion. In this case, the front end portion 11 formed integrally with the barrel body 10 in the above embodiment is configured as a connection member of another component to be screw-connected, and the connection member is screwed to the barrel body. If it is configured to contact the front end surface of the grip portion at the time of connection, the connection member, which is the front end portion, hides the gate mark on the distal end surface of the grip portion when screwed and connected to the barrel body. At the same time, looseness is prevented by the frictional force of the convex or concave gate mark on the front end face of the grip portion.

The above embodiment is an example of a writing implement composed of a front shaft part and a rear shaft part. However, a shaft barrel of a writing implement in which the front shaft part and the rear shaft part are integrally formed. In the above, the grip portion may be formed on the front end side of the barrel by the above-described double molding.

In the above molding method, the runner 32 formed in the second step may be separated when the secondary molding die 2 is removed. Since it is made of an elastic resin material, it is difficult to be separated by elongation. Therefore, it is preferable to separate after being naturally cooled in a later step as in the present embodiment.

[0028]

According to the present invention, since the gate mark is formed on the end face of the grip portion, the appearance of the gate is deteriorated by the gate mark formed on the surface of the grip portion as in the related art, or the grip portion is gripped. It does not cause a feeling of incongruity in the grip feeling. In addition, it is not necessary to perform post-processing of the gate trace by cutting, polishing, or the like in order to improve the external appearance, and it is possible to eliminate complexity and difficulty in work and increase in cost of the product due to the post-processing. Furthermore, according to the aspect in which the connection member is screw-connected to the shaft cylinder main body, when the connection member is screw-connected to the shaft cylinder main body, the gate trace can be hidden by the connection member, and the convex shape or The connection member can be prevented from loosening due to the frictional force of the concave gate mark. Therefore, if the main body of the barrel is the front shaft of the writing instrument and the connecting member is the rear shaft of the writing instrument, the rear shaft is gripped by the rear shaft when the front shaft is screwed to the rear shaft. The gate mark on the rear end face of the portion is hidden, and loosening of the rear shaft portion is prevented.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a shaft cylinder with a grip according to the present invention.

FIG. 2 is a perspective view showing the shaft cylinder with the grip.

FIGS. 3A to 3C are cross-sectional views sequentially showing states in which a barrel body is molded by a primary molding die in the method of molding a barrel cylinder with a grip.

FIG. 4 is a cross-sectional view showing a state in which the core pin mold shifts from between the first movable dies to between the second movable dies in the method of molding the shaft cylinder with the grip.

5A to 5C are cross-sectional views sequentially showing a state in which a grip portion is formed on the outer periphery of the barrel body by a secondary molding die in the method of forming the barrel with a grip.

[Explanation of symbols]

1: primary molding die 2: secondary molding die 10: barrel body (front shaft part) 20: connecting member 30: grip part 31: gate mark A: barrel barrel with grip

Claims (3)

(57) [Claims] In a shaft cylinder with a grip provided with a grip portion on the outer periphery of a shaft cylinder main body by double molding, the shaft cylinder main body has a connecting member on a front end side or a rear end side thereof.
The grip portion is formed so as to be screw-connected.
The end face on the side where the connecting member to be connected
A shaft cylinder with a grip characterized by forming traces . 2. The shaft barrel main body is a front shaft portion of a writing instrument, the connecting member is a rear shaft portion of the writing instrument, and the grip portion is a portion after the rear shaft portion to be screwed and connected comes into contact. the end face, wherein, characterized in that the formation of the gate trace
Item 2. A shaft cylinder with a grip according to Item 1 . 3. A forming method in which the grip portion is secondarily formed in the second step on the outer periphery of the shaft cylinder main body which is first formed in the first step. the cavity of the mold, characterized by injecting the elastic resin material which is melted in the axial direction from the end portion claims
Item 3. A method for molding a shaft cylinder with a grip according to Item 1 or 2 .