JPS5923952B2 - Manufacturing method of recoilless urethane hammer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a recoilless urethane hammer.

A so-called recoilless hammer is already known, in which a hollow chamber is provided in the head of the hammer (in the order of striking) and a granular or block-shaped inertial body is enclosed inside the hollow chamber. The inertia body has the effect of suppressing the recoil that occurs when striking, and has the advantage of preventing vibrations caused by the recoil from being transmitted to the operator's hands, reducing worker fatigue, and is useful in various fields. Widely used in the workplace.

On the other hand, a hammer whose striking surface is made of or covered with an elastic material such as rubber or synthetic resin is
Since it does not damage the surface being struck, it is widely used in the wood and sheet metal industries.

This type of hammer also has the advantage of fire protection, as it does not produce sparks when striking metal surfaces.

Hammers having both the above-mentioned recoilless effect and non-damaging properties on the surface being struck are also already known.

For example, the hammer disclosed in Japanese Patent Publication No. 51-9198 has a cylindrical spline member (core frame of the handle) that serves as the skeleton made of metal material such as brass, and the inside is filled with small lead particles, sand, etc. It is made by attaching a capsule-shaped head with lids closed at both ends, and encasing the whole thing in urethane resin to form a hammer-shape.

When manufacturing this hammer, it is necessary to make the frame member from metal in advance (especially when manufacturing the head member, the inside must be sealed when enclosing particles such as lead and capping both ends). Great care must be taken to ensure that the chamber is completely airtight, making it unsuitable for mass production and resulting in high production costs.

The purpose of the present invention is to efficiently manufacture a hammer that has both recoilless and non-damaging effects on the striking surface at a low production cost.
It is about providing.

The present invention utilizes the molding properties of urethane resin to provide a hollow chamber within the striking head, enclose an inertial body such as iron sand or lead bullets in the hollow chamber, and mold the handle and the striking order integrally. This invention relates to a method for producing a recoilless urethane mer characterized by the following.

The present invention will be explained below with reference to the drawings.

FIG. 1 shows an embodiment of a hammer manufactured by the method of the present invention.

A striking order 2 is integrally formed at the tip of the handle 1, a hollow chamber 3 is provided in the center thereof, and iron sand 4 is movably stored inside the hollow chamber 3.

Reference numeral 5 denotes a lid, which is used when enclosing iron sand 4 in the second step, facilitates filling with filler 6, and forms one striking surface portion.

FIG. 2 shows the molding die 9. FIG. Mold member 10 for forming an opening in a portion corresponding to one of the striking surfaces in striking order 2
Indicates the state in which the is installed.

As shown in FIG. 3, the mold member 10
It is a thick rod shape.

The other side of the mold (not shown) is combined,
The urethane resin raw material is injected through the injection port 11.

It is preferable that the urethane resin is cured with a hardening agent to a Shore A hardness of 70° to 99°.

After the urethane resin has hardened, the mold is removed, and an appropriate amount of inertial material such as iron sand or lead bullet is inserted through the opening formed by the mold member 10.
It is closed by a lid 5 to form a hollow chamber 3.

For the lid 5, an elastic material such as a resin plate exhibits excellent adhesion and is optimal.

After forming the hollow chamber 3 with the lid 5, the opening is filled with the same urethane resin to form one striking surface.

When filling in this second step, as shown in FIG. 4, if small holes 15 and 15 are provided in the opening toward the outer periphery of the blowing order, the urethane resin will flow in and harden, and the filling material 60 It is effective because it makes the connection with the main body more secure and prevents it from coming off.

The small holes 15, 15 are formed by installing pin-shaped mold members 16, 16 in the molding die 9, as shown in FIG.

Mold member 1 forming an opening for forming hollow chamber 3
As shown in FIG. 9, 7 may be a plate-shaped body with a semicircular lower end.

In this case, the mold 9 is manufactured so as to be installed at a location corresponding to the top of the striking head, as shown in FIGS. 7 and 8.

After demolding, as shown in FIG. 6, an inertial body such as iron sand is put in and the lid 18 is closed, and then the top of the blowing order is filled, and then the blowing order 2 is filled.
form.

As shown in FIG. 10, inserting a plastic or metal core frame 20 into the center of the handle 1 helps to improve the balance between the handle 1 and the striking order 2 when using relatively soft urethane resin. It is valid.

A specific example of implementing the present invention is shown below.

Thermosetting urethane resin "Adiprene" (trade name of DuPont) is preheated to 80 degrees, defoamed under reduced pressure, hardening agent "Curemin" (trade name) is mixed at a ratio of 12 parts to 100 parts of raw material, and released from the mold. Inject it into the mold coated with the agent (Fig. 2), and
The mold was placed in an oven at 00°C to harden, and was demolded after 1 hour.

Put iron sand in an amount equal to 1/4 of the amount of the hollow chamber into the opening of blowing order 2, close the lid 5 to form the hollow part 3, and add "aziprene" mixed with the same hardening agent as mentioned above to the opening. Fill it with
A striking surface portion was formed and aged at 80° C. for 24 hours.

This hammer had a hardness of 90° Shore A, had all the requirements necessary for a hammer, such as wear resistance and impact resistance, and had an extremely good recoilless effect.

Urethane elastic bodies are known to have hardness, high resilience, excellent impact resistance, and wear resistance.

In addition, it is possible to manufacture from low hardness to high hardness depending on the combination of raw materials, and it is particularly easy to mold according to the mold structure.

A rubber made from a urethane elastomer with such characteristics has excellent abrasion resistance and impact resistance, and exhibits an excellent non-recoil effect.

According to the method of the present invention, in order to form a hollow chamber inside the striking order, unlike known methods, there is no need to prepare a metal capsule-like container in advance, and it is possible to simply repeat molding. Since it can be manufactured in large quantities, production costs can be significantly reduced.

Further, according to the method of the present invention, it can be made entirely of urethane resin, which has the advantage of not generating sparks during use and having an electrically insulating effect.

[Brief explanation of drawings]

FIG. 1 is a front sectional view of a hammer manufactured according to an embodiment of the present invention, FIG. 2 is a front view of a molding die, and FIG. 3 is a perspective view of a mold member for forming a hollow part. Fig. 4 shows one embodiment...a front sectional view of the head of the mer, Fig. 5 is a partial front view of the mold, and Fig. 6 shows the construction section of the mer head according to another embodiment. 7 is a front view of the mold, FIG. 8 is a sectional view taken along the line ■ in FIG. 7, and FIG. 9 is a perspective view of a hollow part forming mold member according to another embodiment. , FIG. 10 is a front sectional view of another embodiment. The symbols representing the main parts of the figure are as follows. 1...Handle, 2...Blow order, 3.Hunnel, hollow chamber, 4...Iron sand (inertial body), 5,18...
... Lid, 6 ... Filler, 9 ... Molding mold, 10 ... Rod-shaped mold member, 15 ...
・Small hole, 17... Plate mold member.

Claims (1)

[Claims] 1. In a recoilless urethane hammer that has a hollow chamber in the striking head and has an inertial material sealed in the hollow chamber, when the handle and the striking order are integrally molded by a mold, the striking of one of the molds A mold member is placed in the recess for forming the head, thereby forming a hollow part within the striking head, and after the hammer is formed and demolded, an inertia material is placed in the hollow part, and a homogeneous urethane resin is placed. A method for manufacturing a recoilless urethane hammer characterized by a lid.