JPH02281916A - Brush handle and mold therefor - Google Patents

Abstract

PURPOSE:To make the external appearance after molding favorable and consequently obviate the need of finishing process and realize the favorable feeling in use by a method wherein wall face, which is normal to the parting line face, is recessedly provided in the edge face of a handle and to which a submarine gate is connected. CONSTITUTION:A wall face 14, which is normal to the parting line face, is recessedly provided in the edge face of a brush handle 11. The wall face 14 is planar or quadric and a submarine gate 12 is formed so as to connect to the wall face 14. When the distance (a) between a handle eye 13, which is formed near the edge face of the brush handle 11, and the wall face 14 is made to be 10mm or less, the jetting mark, which easily tends to develop on the surface of a product at molding, remains inside the handle eye 13 and within the surroundings of the handle eye, resulting in not impairing the external appearance of the product. Thus, the cut-off face of the gate in the brush handle neither attracts the attention of a user nor mars its feeling in use. Further, the surface of the product has smoothly finished one, favorable printable finish and the like, fine exterior appearance and degrees of freedom on design and enhanced commercial value.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a brush handle such as a toothbrush and a mold for molding the brush handle.

[Conventional technology]

Conventionally, brush handles have generally been injection molded from synthetic resin, and the side gate method has often been adopted as the gate method during molding.

The side gate method is suitable for molding thick brush handles because the gate cross section can be made into a circle with a diameter of 3 to 5 mm or a square with a side of 3 to 5 fi. However, on the other hand, after molding, the gate is cut with a saw or the like, and finishing steps such as removing the blade marks left on the cut surface and wiping off the chips are required, which becomes an obstacle to cost reduction.

Gate cutting is a drawback of this type of side gate method.
In order to avoid the finishing process, the submarine gate method has come to be widely adopted. This is because in the submarine gate method, when the surface provided with the gate is parallel to the mold release direction of the product, that is, perpendicular to the PL plane, cut pieces of the gate are unlikely to remain on the product.

[Problem to be solved by the invention]

However, as shown in Figure 5, the end surface of the brush handle on the gate side is generally a spherical surface or a curved surface close to it, so the surface of the product provided with the submarine gate 2 is not perpendicular to the PL surface. , the cut pieces of the submarine gate 2 will remain, and if these cut pieces remain as protrusions even if only a small amount, it will not only have a negative effect on the touch when gripping the brush handle 1, but also will affect the appearance. Bad,
Reference numeral 3 in Figure 0 indicates a handle hole formed near the end surface of the brush handle 1, which required a finishing process because it affected the commercial value.

In addition, the problem with using a submarine gate is that the resin injected from the gate directly splashes onto the surface of the mold, leaving marks, which significantly impairs the appearance of the product.This phenomenon is much more pronounced than when using a side gate. Furthermore, when a submarine gate is provided in the stationary mold, the gate is cut when the mold is opened, but the cutting resistance is large and the product may remain in the cavity of the stationary mold.

The present invention solves the various problems of the conventional submarine gate method, improves the appearance after molding, eliminates the need for a finishing process, provides a good feeling of use, provides freedom in design, and has commercial value. The object of the present invention is to provide a brush handle and a mold for molding the brush handle, which significantly improves the workability during molding, and facilitates cost reduction.

[Means to solve the problem]

The present invention is characterized in that a wall surface perpendicular to the PL surface is recessed in the end surface of the handle, and a submarine gate is connected to the vertical wall surface, and a handle hole is formed within a distance of 10 m1 from the wall surface. This brush handle is also characterized by the fact that it has a .

The present invention also provides a mold consisting of a pair of a fixed side and a movable side forming a cavity for the brush handle, and a convex portion for recessing a wall surface perpendicular to the PL plane in the end face of the handle. This brush handle mold is characterized in that a submarine gate is provided on the convex portion.

Furthermore, in the brush handle mold, the center of the submarine gate is provided at a distance of 11 or more from the upper end of the convex portion toward the PL surface, or the center of the submarine gate is provided at a distance of 2.1 or more from the PL surface. It is good to provide
If a pin for forming a pattern hole perpendicular to the PL plane is provided on both the fixed and movable molds at a distance of less than 10 mm from the convex portion, or if the submarine gate is provided on the fixed mold, this fixation It is also effective to make the draft angle of the pin for forming the handle hole in the side mold twice or more that of the movable mold.

0 action] In the brush handle of the present invention, when a pair of fixed molds and a movable mold are combined and resin is injected and press-fitted into the cavity from the submarine gate, at the same time as the brush handle is molded, a part perpendicular to the PL plane is formed in the end face of the handle. Since the wall surface is recessed, the cut surface of the gate is not noticeable, and even if some protrusion remains on the gate, the protrusion will not extend beyond the end of the handle and the bottom will not touch the protrusion directly. , does not adversely affect the feeling of use.

In addition, by placing the center of the submarine gate of the mold at least 1 wm away from the upper end of the convex part that forms the wall surface perpendicular to the PL surface toward the PL surface, the gate cut portion of the mold can be easily processed.
The remaining 7 gates of the product are less likely to get stringy, and the strength of the mold can be maintained by keeping the center of the submarine gate of the mold at least 2m away from the PL surface.

Furthermore, when forming a handle hole near the end face of the brush handle, the handle hole forming pin is moved from the submarine gate so that the handle hole is formed within 1011 degrees from a wall surface perpendicular to the PL plane recessed in the handle end face. If prepared within 10 ms, the resin will easily collide with the pin for forming the handle hole during injection molding, and the jetting marks will remain only inside the handle hole and its vicinity, and the appearance of the product will not be impaired.

In addition, if a pin for forming a pattern hole is provided and a submarine gate is provided on the fixed side mold, the gate will be cut when the mold is opened, but the product will not come out of the fixed side mold cavity (mold release). The resistance becomes large and the product often remains in the fixed mold, but by making the draft angle of the pin for forming the handle hole in the fixed mold more than twice that of the movable mold, the opening of the mold can be improved. Reduces mold release resistance from the mold cavity on the fixed side of the product,
The product can be kept in the cavity of the moving mold.

(Embodiments) If the embodiments of the present invention are described with reference to the drawings, first to third
In the figure, a wall surface 14 perpendicular to the PL plane is recessed in the end surface of the brush handle 11, and this wall surface 14 may be a flat surface as shown in the first drawing or a quadratic curved surface as shown in the second drawing. Submarine gate 12 at 14 (see Figure 3.4)
are connected and molded.

13 is a handle hole formed near the end face of the brush handle 11, and the distance between the handle hole 13 and the wall surface 14 is l! 1lta to 10n
If it is within this range, jetting marks that tend to occur on the surface of the product during molding will be confined only to the inside of the handle hole 13 and its vicinity, and the appearance of the product will not be impaired.

Further, the brush handle molding mold of the present invention, as shown in FIG. A cavity 17 is formed, and a convex portion 18 for recessing a wall surface perpendicular to the P L plane is formed in the end face of the handle, and a submarine gate 12 is provided in this convex portion 18.

In this case, the position of the submarine gate 12 is such that the center of the gate is at least one fin from the upper end of the convex portion 18 (wall surface 14 in the end surface of the handle 11) to the PL surface side, and the gate is cut in the mold. It is better to make the part easier to process and to avoid leaving gate residue on the product.

Further, it is also preferable that the distance C between the center of the gate and the PL plane be set to 21 or more to maintain the strength of the mold.

Furthermore, when the handle hole 13 is formed near the end of the handle, the handle hole 13 is formed to penetrate through the product symmetrically with respect to the longitudinal axis of the product in front of the submarine gate 12 (on an extension of the center line of the gate). A pin 19 for forming a stalk perpendicular to the PL plane is provided at the position where the hole is formed (see Fig. 1.2), but the distance a' between the pin 19 for forming a stalk and the convex portion 18 must be within 10 fins. For example, when resin is injected into the cavity 17 from the submarine gate 12, the resin collides with the handle hole forming pin 19,
The jetting marks remain only on the inside of the handle hole 13 and its vicinity, and the product has a good appearance.

As shown in the fourth figure, the handle hole forming pin 19 is inserted into the fixed side mold 15, the fixed side mold 719-1, and the movable side mold 16.
The movable side pin 19-2 can be inserted into the moving side pin 19-2. In that case, both have a draft slope toward the PL plane, and when the submarine gate 12 is provided in the fixed side mold 15 as shown in the fourth figure, the draft slope of the fixed side pin 19-1 is set on the moving side. If it is more than twice the draft angle of pin 19-2,
The mold release resistance of the fixed side mold 15 of the product from the cavity is reduced.

〔Effect of the invention〕

As described above, according to the present invention, the cut surface of the gate of the brush handle is not noticeable and does not impair the usable area.
The product surface has a smooth finish, which improves the print finish, etc., and it has good appearance and freedom in design, increasing product value.It also makes mold processing easier and maintains strength. This has many beneficial effects, such as making it easier to release the product from the mold, improving workability during molding, and facilitating cost reduction.

[Brief explanation of drawings]

FIG. 1 is a plan view of the end of the brush handle showing one embodiment of the present invention, FIG. 2 is a plan view of the end of the brush handle showing another embodiment of the invention, and FIG. 2 is a cutaway side view, FIG. 4 is a partially cutaway side view of the mold of the present invention, and FIG. 5 is a side view of the end of a brush handle showing a conventional example. 1.11... Brush handle, 2.12... Submarine gate, 3, 13... Handle hole, 14... Wall surface, 1
5... Fixed side mold, 16... Moving side mold, 17...
・Cavity, 18... Convex part, 19... Pin for pattern hole formation, 19-1... Fixed side pin, 19-2... Moving side pin, a, a', b, c... ·distance. Figure 1 Figure 5 Figure 2

Claims (7)

[Claims] (1) A brush handle characterized in that a wall surface perpendicular to the PL surface is recessed in the end surface of the handle, and a submarine gate is connected to the vertical wall surface. (2) The brush handle according to claim 1, wherein the handle hole is formed within a distance of 10 mm from the wall surface. (3) A mold consisting of a fixed side and a movable side that form a cavity for the brush handle, with a PL inside the handle end surface.
A mold for forming a brush handle, characterized in that a convex portion is formed for recessing a wall surface perpendicular to the surface, and a submarine gate is provided on the convex portion. (4) The brush handle mold according to claim 3, wherein the center of the submarine gate is provided at a distance of 1 mm or more from the upper end of the convex portion toward the PL surface. (5) Set the center of the submarine gate 2mm from the PL plane.
The brush handle molding die according to claim 3 or 4, which is provided at a distance of at least the above distance. (6) A mold for forming a brush handle according to claim 3, 4 or 5, wherein a pin for forming a handle perpendicular to the PL plane is provided on both the fixed side and movable side molds at a distance of within 10 mm from the convex portion. Type. (7) providing the submarine gate on the fixed side mold;
7. The mold for forming a brush handle according to claim 6, wherein the draft angle of the pin for forming the handle hole of the mold is at least twice that of the movable mold.