JPH0325910Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Technical Field) The present invention is an approximately T-shaped device in which a head portion and a handle portion are integrally molded from a predetermined resin material, and a predetermined core material is embedded inside them. In particular, the head core material embedded in the head portion and the handle core material embedded in the handle portion are separated, so that the shape of the handle portion during hammer impact is reduced. The present invention relates to a technology for improving the durability of an integrally molded hammer that reduces impact.

(Background Art) Conventionally, as a hammer used at various construction sites, work sites, etc., there has been an integrally molded hammer having a generally T-shaped outer shape, in which a head portion and a handle portion are molded from a predetermined resin material. However, in such integrally molded hammers, conventionally, in order to obtain enough strength to withstand the impact when the hammer is struck, a core material having a substantially T-shape is provided inside the head and handle. It was common for them to be buried. For this reason, conventional integrally molded hammers have had the disadvantage that the impact upon striking the hammer is directly transmitted from the handle to the operator's hand via the core material, imposing a severe labor burden on the operator.

On the other hand, in the above-mentioned integrally molded hammer, a cavity is formed inside the core material buried in the head part, and lead grains are housed in the cavity, and the friction of the lead grains causes the hammer to strike. A so-called shock hammer has been proposed that absorbs the impact of
However, with such a cutless hammer, the impact force of the hammer itself decreases due to the friction of the lead grains, so there is a problem in that the number of hits required for the work increases and the work efficiency decreases. In addition, after the lead particles are pulverized by the impact of a hammer strike, they tend to agglomerate again due to frictional heat, forming a lump-like shape.
There was also a fear that the shock-reducing function would not be effective.

Therefore, the applicant of this application first filed a patent application filed in 1983-
In No. 33417, a head portion and a handle portion are integrally molded with a predetermined resin material in a substantially T-shape, and an elongated head portion core material is attached at one end in the longitudinal direction of the head portion. A predetermined handle core material is embedded in an exposed state in a striking part formed on the side, and a predetermined handle core material is cut off from the head core material, and the handle is separated by the resin material. We proposed an integrally molded hammer that is embedded inside the part.

According to such an integrally molded hammer, the impact at the time of hammer impact is absorbed by the resin material interposed between the head core material and the handle core material, and the impact between the head part and the handle part is reduced. Since the transmission is greatly reduced, the impact transmitted to the worker's hands is reduced, and the labor burden on the worker is reduced. In addition, unlike the conventional shockless hammer, the impact is not alleviated by the friction of lead particles, so the shock prevention function can be effectively exerted over a long period of time. There is no possibility that the striking force will decrease and the work efficiency will decrease.

(Problem to be solved by the invention) By the way, in such an integrally molded hammer, since the shape of the core material of the head part is easy to design and manufacture, the part buried in the head part is usually It is conceivable to have a columnar shape with an equal cross-sectional shape over the entire length, but if the buried part of the head core material is made into a mere columnar shape like that,
When impact is performed at the end of the head on the side covered with resin material, there is a problem that the resin material cracks relatively early near the end of the buried side of the head core material, resulting in poor durability. Not always fully satisfied in terms of sexuality.

(Means for solving the problem) The present invention was made in view of the above circumstances, and its gist is that the head portion and the handle portion are approximately T-shaped as described above. The head is integrally molded with a predetermined resin material, and a longitudinal head core material is formed in the longitudinal direction of the head.
It is buried in an exposed state in the striking part formed on one end side, and a predetermined handle core material is cut off from the head core material and separated by the resin material. In the integrally molded hammer embedded in the handle, the head core is located near the end opposite to the striking part in a predetermined length of the end opposite to the striking part. Indeed, the reason is that the structure is made so that the dimension in the direction perpendicular to the longitudinal direction is small.

(Functions and Effects of the Idea) According to such an integrally molded hammer, the shock-reducing function that reduces the impact when struck by the hammer can be satisfactorily exhibited over a long period of time, and work efficiency can be improved. Not only can various effects be obtained by separating the head core material and the handle core material, but also the head core material can be improved when striking with the end of the head covered with the resin material. Compared to the case where the part buried in the head part of the material is simply columnar, cracks are less likely to occur in the resin material near the buried end of the head part core material, and the durability of the hammer is increased accordingly. It will improve. This is because the buried portion of the head core material has the above-mentioned configuration, so that the impact load upon hammer impact is dispersed compared to a case where the buried portion of the head core material is simply columnar. This is thought to be due to the fact that the stress at the part where the resin material cracks is reduced.

(Example) Hereinafter, in order to clarify the present invention more specifically, one example thereof will be described in detail based on the drawings.

1 and 2 show a front view and a side view, respectively, of a hammer 10 according to the present invention. This hammer 10 has a head portion 12 and a handle portion 14.
, which form a substantially T-shape, are integrally molded with a hard urethane resin material 16 having a hardness (Shoer hardness Hs-D scale) of about 60. In the head portion 12 of the hammer 10, a machine structural carbon steel S is provided along the longitudinal direction.
A head core material 18 with a circular cross section made of 55C is embedded, while a handle core material 20 with a circular cross section made of machine structural carbon steel S40C is embedded in the handle 14 along its longitudinal direction. ing.

As is clear from FIG. 3, the head core member 18 has a large diameter portion 22 at one end that is approximately equal to the outer diameter of the head portion 12, and a narrow diameter portion that is slightly smaller than the other end. 24, and is embedded in the head portion 12 with the large diameter portion 22 exposed at one end side of the head portion 12 in the narrow diameter portion 24. The large diameter portion 22 of the head core material 18 constitutes one striking portion of the hammer 10, and the end portion of the head core material 18 on the narrow diameter portion 24 side is made of a resin material having a predetermined thickness. 16 constitutes the other striking portion of the hammer 10. Note that a groove 26 is formed in the circumferential direction at the connecting portion of the narrow diameter portion 24 to the large diameter portion 22, and the resin material 16 enters the groove 26, whereby the head member core material 18 is firmly held by the resin material 16.

On the other hand, the handle core material 20 is disposed such that one end thereof is separated from the outer peripheral surface of the narrow diameter portion 24 of the head core material 18 by a distance of 5 mm. It is separated from the head member core material 18 by a resin material 16 inserted and interposed in the gap. The end portion of the handle core material 20 facing the head core material 18 is chamfered, so that the end portion of the handle core material 20 is chamfered when struck by a hammer. The impact load applied to the vehicle is well distributed.

In such a hammer 10, the narrow diameter portion 24 of the head core material 18 is formed into a cylindrical portion 28 having a constant outer diameter at approximately half the length on the large diameter portion 22 side. The remaining portion is a truncated cone-shaped tapered portion 30 whose outer diameter gradually decreases from the boundary with the cylindrical portion 28 toward the end opposite to the large diameter portion 22. In this embodiment, the taper angle of the outer peripheral surface of the tapered portion 30 is set to about 6°, and the length of the tapered portion 30 is set to about 28 mm.

According to such a hammer 10, a gap of 5 mm is provided between the head core material 18 and the handle core material 20, and the urethane resin material 16 enters and intervenes in the gap. Because there is
The impact transmitted to the handle 14 during hammer impact is significantly reduced, and the impact transmitted to the operator's hand via the handle 14 is reduced. In addition, unlike hammers that absorb shock through the friction of lead particles, there is no risk that the shock-reducing function will deteriorate during use, so good impact-reducing effects can be obtained over a long period of time. Since the impact force is not reduced by the friction of the lead particles, there is no reduction in work efficiency.

Moreover, according to the hammer 10, when a strike is performed at the striking portion on the side covered with the urethane resin material 16, the resin material 16 is applied near the end of the head core material 18 on the side closer to the striking portion. The occurrence of cracks was well suppressed, and the narrow diameter portion 24 of the head core material 18 was made into a cylindrical portion 28 with a constant outer diameter over its entire length, as shown in FIG. Compared to the hammer 32, it has the advantage of significantly improved durability. This is because, as described above, the narrow diameter portion 24 of the head member core material 18 is formed into a tapered portion 30 at approximately half the portion located on the opposite side from the large diameter portion 22, and the large diameter portion is formed in the tapered portion 30. Since the outer diameter is made smaller toward the end opposite to 22, the narrower diameter portion 2
This is believed to be because the impact load at the time of impact is dispersed compared to the case where the entirety of the resin material 16 is made up of the cylindrical portion 28, thereby reducing the stress on the portions of the resin material 16 that are prone to cracking.

Incidentally, in a striking test under similar conditions using the striking part on the side covered with the urethane resin material 16, the hammer 32 shown in FIG.
While it was observed that cracks were generated in the resin material 16 after being struck approximately 1,000 to 9,000 times, in the hammer 10 according to this embodiment, cracks were observed after being struck approximately 20,000 to 22,000 times. It has also been found that no cracks occur in the resin material 16.

Although one embodiment of the present invention has been described above, this is a literal illustration, and the present invention should not be interpreted as being limited to this specific example.

For example, in the above embodiment, the head core material 18 and the handle core material 20 are each made of carbon steel for mechanical structure.
Made of 55C and S40C,
The core materials 18 and 20 are hard urethane resin materials 1
Although the hammer 10 is constructed by integrally molding the parts 6 and 6, it is also possible to use other materials as the core material and resin material.

Further, in the above embodiment, the length of the tapered portion 30 in the narrow diameter portion 24 of the head core material 18 and the taper angle of its outer peripheral surface are approximately 28 mm and approximately 28 mm, respectively.
Although it was assumed to be 6°, these dimensions can be changed as appropriate depending on the resin material, the dimensions of the hammer, etc. Note that the length of the tapered portion 30 is usually 25 to 30 mm.
It will be set within a range of about mm.

Furthermore, the distance between the head core material 18 and the handle core material 20 is not necessarily limited to 5 mm, and may vary depending on the resin material, the size of the hammer, etc., similar to the dimension of the tapered portion 30 described above. It can be changed as appropriate.

Although not listed in detail, it goes without saying that the present invention can be implemented with various modifications and improvements without departing from the spirit thereof.

[Brief explanation of the drawing]

FIG. 1 is a front view showing an embodiment of a hammer according to the present invention, and FIG. 2 is a side view thereof. Third
The figure is a partially cutaway front view showing the main parts of the hammer in Figure 1, and Figure 4 corresponds to Figure 3, which shows an example of the hammer used to compare the durability with the hammer in Figure 1. This is a diagram. 10...Hammer, 12...Head part, 14...
Handle portion, 16... Hard urethane resin material, 18...
Head part core material, 20... Handle part core material, 22... Large diameter part (striking part), 24... Small diameter part, 26... Groove part,
28...Cylindrical part, 30...Tapered part.

Claims (1)

[Claims for Utility Model Registration] (1) The head portion and the handle portion are integrally molded with a predetermined resin material in a substantially T-shape, and a longitudinal head portion is formed in the longitudinal direction of the head portion. A part core material is buried in an exposed state in a striking part formed on one end thereof, and a predetermined handle part core material is cut off from the head part core material and separated by the resin material. The integrally molded hammer is embedded in the handle part in a pressed state, and the hammer part core material is connected to the striking part at a predetermined length portion of the end opposite to the striking part. An integrally molded hammer characterized in that the dimension in the direction perpendicular to the longitudinal direction becomes smaller as it approaches the opposite end. (2) The head part core material is composed of a large diameter part constituting the striking part and a narrow diameter part embedded in the resin material of the head part, and the narrow diameter part is smaller than the large diameter part. The integrally molded hammer according to claim 1, wherein a circumferential groove is provided around the connecting portion.