JPH04348883A - Resin head hammer and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide a resin head hammer which can prevent a slip and a come-off between the head and the grip handle thereof, and to provide a method of manufacturing thereof. CONSTITUTION:A resin head hammer is made of a first resin material for forming a resin head, and a second resin material for forming a hammer grip handle, these resin materials being integrally molded. The second resin material is charged into a through-hole part or a hollow part communicated with the through-hole part. With the use of a die for molding the hammer grip handle, in which a sprue or a runner is formed and is also formed therein with a gate in the grip handle attaching part, a molten resin is fed into the die through the sprue or the runner and the gate so as to form the resin head.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hammer whose head portion is made of resin and a method for molding the hammer.

0002

[Prior Art] Conventionally, hammers whose heads are made of resin are disclosed in Japanese Utility Model Application No. 157189/1989 and Japanese Utility Model Application No. 1/99/1999.
No. 577, as well as Utility Model Application No. 57-153481 and No. 62
Those described in JP-A-198079 and JP-A-64-1877 are known.

0003

[Problem to be solved by the invention] Utility Model Application No. 60-1571
The hammers described in No. 89 and Japanese Utility Model Application Publication No. 1-99577 have a resin head attached to a general wooden or metal handle. However, in these hammers, although the distal end portion of the handle is enlarged to prevent the head from coming off, the problem is that it is ineffective against displacement of the head toward the gripping portion.

[0004] In this regard, the hammers described in Japanese Utility Model Application Publication Nos. 57-153481, 62-198079, and 64-1877 have the entire head and handle integrally molded with resin to prevent the head from coming off or slipping. completely prevented. However, since these hammers are made only of resin, the handle part is too soft and bends or bends too much during use, which is inconvenient, so a core material must be inserted into the handle. It has the disadvantage that molding is complicated. Furthermore, since the entire head is integrally molded, the mold is larger and the cost is higher than when only the head is molded from resin.

[0005]

OBJECTS OF THE INVENTION Therefore, an object of the present invention is to provide a resin head hammer and a method for molding the same, which prevents the head and handle from slipping or coming off.

[0006]

[Means for Solving the Problems] In order to achieve the above object, the present inventors have made extensive studies and have arrived at the present invention.

That is, the resin head hammer according to the present invention includes a resin constituting the resin head, a through hole formed in the head attachment portion of the hammer handle, and a hollow portion continuous to the through hole filled with the resin. It is characterized by being integrally molded with the resin.

Further, in a preferred embodiment of the resin-head hammer according to the present invention, a through-hole portion continuous with the hollow portion is formed in the gripping portion of the handle, and the resin protrudes from the through-hole portion to prevent slippage. It is said that it constitutes a department.

Furthermore, the method for molding a resin head hammer according to the present invention uses a hammer handle having a spool or runner formed inside and a gate formed in the head attachment portion of the handle. It is characterized by feeding molten resin into a mold via a hand spool or runner and gate to mold the resin head.

0010

[Operation] According to the present invention, the molten resin passes through the inside of the handle as a spool or runner and is fed into the mold from the gate formed in the head attachment part of the handle, so that the resin forming the resin head Since it is integrated with the resin inside the handle, it is possible to completely prevent the head from coming off or shifting.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic cross-sectional view showing a mold with a handle set, FIG. 2 is a cross-sectional view showing an example of a resin head hammer according to the present invention obtained using the mold shown in FIG. 1, and FIG.
FIG. 3 is a sectional view showing another example of the resin head hammer according to the present invention.

In FIG. 1, 1 indicates two split molds 1A and 1B.
After each molding process, a handle member 4 having the configuration described below is set, resin is injected into the cavity 2 of the mold 1 by a resin injection nozzle 3, and as shown in FIG. A resin head hammer 5 having a resin head 6 molded with resin is molded on the head attachment portion of the handle 4 as shown.

In the present invention, the handle member 4 set in the mold 1 has one or more through holes 4B formed in the portion where the resin head 6 is attached, and one or more through holes 4B are formed continuously with the through holes 4B. A hollow portion 4A is formed. The position of the through-hole portion 4B is preferably approximately at the center of the portion where the resin head 6 is attached after molding. In addition, the diameter and number of the through holes 4B are appropriately determined depending on conditions such as the size and material of the handle member 4 used, the type of resin, and the required strength of the resin head 6 obtained. It is preferable to provide them at approximately equal intervals in terms of uniform molding.

The molding method according to the present invention uses a mold 1 as shown in FIG. After passing through the hollow part 4A formed in the handle member 4, it is injected into the cavity 2 through the through hole part 4B formed continuously with the hollow part 4A. That is, the hollow part 4A formed in the handle member 4 is used as a spool or a runner, and the through hole part 4B is used as a gate to inject the resin into the cavity 2.

Therefore, in the obtained resin head hammer 5, since the resin is integrated in the resin head 6 and the hollow part 4A and the through hole part 4B which are the inside of the handle member 4, the handle member It is possible to completely prevent misalignment, omission, etc. of item 4. Therefore, when the material and the type of resin of the handle member 4 are the same, the resin head hammer 5 obtained by the molding method of the present invention has greater mechanical strength and better parts function than the conventional resin head hammer. Highly reliable.

Furthermore, since the gate is at approximately the center of the resin head 6 of the resin head hammer 5, which is an ideal position in injection molding, the injected resin flows from approximately the center of the resin head 6 toward the outer peripheral surface of the cavity 2. Since the resin flows uniformly and solidifies as shown by the arrow X, it is possible to obtain a resin head hammer 5 with excellent dimensional stability and precision of the resin head 6, particularly with excellent strength of the striking surface 6A.

Furthermore, in the resin head hammer 5 obtained, since the gate is covered with the resin head 6 itself, no gate marks remain on the surface of the resin head 6, and post-processing such as cutting and polishing is not required. Since there is no change in the finished dimensions due to post-processing, the mold 1 can be designed based on the finished dimensions of the resin head 6 without considering the amount of cutting, the amount of polishing, etc. Therefore, by molding using a mold with the required precision, the resin head 6 with the desired finished precision can be obtained.

In order to further strengthen the integrity of the resin head 6 and the handle member 4, the through hole 4B may be formed in the recess 4D as desired, as shown in FIG.

Furthermore, if the cooled resin at the tip of the resin injection nozzle 3 is injected into the cavity 2, it may cause defects such as flow marks and short shots. It is preferable to form a cold slug well portion 4C at the tip (or end) of the hollow portion 4A of the member 4.

Furthermore, in this embodiment, the resin is injected from the resin injection nozzle 3 into the handle member 4 via the mold spool or runner 1C of the mold 1, but the present invention is not limited to this. First, a resin injection nozzle 3 is attached to the end of the handle member 4.
Alternatively, the resin may be directly injected by pressure contact. Injection of resin is
Not limited to the end of the handle member 4 on the side closer to the resin head 6,
It may be from the surface of the handle member 4, or from the far end as shown in FIG. Furthermore, in FIG. 3, the handle member 4
By forming a through-hole portion 4E in the gripping portion and forming the non-slip portion 7 by molding resin to protrude from the through-hole portion 4E, it is possible to prevent the gripping portion from slipping during use. Although the anti-slip portion 7 is formed at the rear end portion of the handle member 4 in FIG. 3, a plurality of anti-slip portions 7 may be formed over the entire grip portion and the entire circumference.

Although the embodiments of the resin head hammer and molding method thereof according to the present invention have been described above, the present invention is not limited to the above, and may be modified as appropriate within the scope of the present invention depending on the mode of the resin head hammer to be molded. be able to. In addition, examples of materials used for the handle member 4 and the resin head 6 are shown below.

Materials for the handle member 4 used in the method of the present invention include wood and synthetic resin, which are variously known as hammer handle members, as well as metals such as iron, stainless steel, aluminum, and brass, or alumina and carbonized materials. Materials such as ceramics such as silicon, other heat-resistant plastic materials, reinforced wood (paper pulp, etc.), bamboo materials, etc. can be used, and the resin contacting surface may be knurled.

The material of the resin to be injected, that is, the resin head 6, may be made of either thermoplastic resin or thermosetting resin. Specifically, the thermoplastic resin may include, for example, , polyethylene, polypropylene, polymethylpentene, polybutene, polybutadiene, polystyrene, styrene-butadiene resin, polyvinyl chloride,
Polyvinyl acetate, polymethyl methacrylate, polyvinylidene chloride, polytetrafluoroethylene, AS resin,
ABS resin, polyacrylonitrile, polyacetal,
Polyamide, polycarbonate, polyphenylene oxide, polyethylene terephthalate, polybutylene terephthalate, polyarylate, polysulfone, polyphenylene sulfide, polyether ether sulfone, polyetheretherketone, polyetherketone, polyetherimide, polyamideimide, polyimide, etc. are used,
Further, as the thermosetting resin, for example, formaldehyde resin, phenol resin, amino resin, unsaturated polyester resin, epoxy resin, diallyl phthalate resin, silicone, polyurethane, polyamino bismaleimide resin, etc. are used, and these may be used alone or in combination. It may be a blend resin of more than one species.

Furthermore, due to the nature of the hammer, these resins are mixtures of fibrous reinforcing materials such as glass fibers, carbon fibers, aramid fibers, ceramic fibers, and metal fibers.
This is preferred because high strength can be obtained. When a fibrous reinforcing material is mixed, according to the present invention, the fibers are oriented in the direction of the arrow X in FIG. This is effective in improving the strength of the striking surface 6A of the head 6.

[0026]

According to the present invention, the molten resin passes through the inside of the handle as a spool or runner and is fed into the mold from the gate formed in the head attachment part of the handle, so that the resin head is configured. Since the resin that holds the handle is integrated with the resin inside the handle, it is possible to completely prevent the head from coming off or shifting.

In addition, since the injected resin flows uniformly from the approximate center of the resin head toward the outer peripheral surface of the cavity and solidifies, the resin head has excellent dimensional stability and precision, especially the strength of the striking surface. You can get a hammer.

Furthermore, the obtained resin head hammer is
Since no gate marks remain on the surface of the resin head, there is no need for post-processing such as cutting and polishing, which can easily disrupt finished dimensions.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing a mold with a handle portion set.

FIG. 2 is a sectional view showing an example of a resin head hammer according to the present invention obtained by the mold shown in FIG. 1;

FIG. 3 is a sectional view showing another example of the resin head hammer according to the present invention.

[Explanation of symbols]

1 Mold 1A, 1B Split mold 1C Mold spool or runner 2 Cavity 3 Resin injection nozzle 4 Handle member 4A Hollow part (spool or runner) 4B Through-hole part (gate) 4C Cold slug well part 4D Recessed part 4E Through-hole Part 5 Resin head hammer 6 Resin head 6A Impact surface 7 Non-slip part

Claims (3)

[Claims] [Claim 1] The resin constituting the resin head and the resin filled in the through hole formed in the head attachment part of the hammer handle and the hollow part continuous to the through hole are integrally molded. A resin head hammer characterized by: 2. A gripping portion of the handle has a through-hole portion continuous with the hollow portion, and a resin protrudes from the through-hole portion to form a non-slip portion. 1. The resin head hammer described in 1. 3. Using a hammer handle that has a spool or runner formed inside and a gate formed in the head attachment part of the handle, melting is carried out through the spool or runner and gate of the hammer handle. A method for molding a resin head hammer characterized by feeding resin in a state into a mold to mold a resin head.