JPS6334860Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a shot prevention (shockless) hammer, and in particular, the head part and handle part are integrally molded from a resin material, and the lead ball is housed in the head part. This invention relates to a shock-preventing hammer that absorbs the impact when the hammer is struck.

Prior Art Conventionally, as a shock prevention hammer, a head part and a handle part are integrally molded from a predetermined resin material, and a cylindrical body made of metal and having a cylindrical shape with a bottom is passed through the head part. A metal cap made of a predetermined metal material is attached to the open end of this cylindrical body to serve as the main striking part, and a cavity is formed in the head part, and a predetermined particle size is formed in this cavity. Accommodates lead balls,
There are known devices that absorb the impact generated when struck by a hammer.

Such anti-shock hammers are for example:
Compared to conventional hammers, such as so-called steel hammers, whose heads are simply made of a cylindrical block made of metal such as steel, which cannot absorb or alleviate the impact that occurs during striking, they are more comfortable for workers during striking work. The transmitted shock is significantly reduced, so that it does not adversely affect the hands of the workers.

Problems to be Solved However, with such shock prevention hammers, there is a problem in that the striking force is generally inferior to that of steel hammers, etc., and the lead balls contained in the hammer convert some of the hammer's striking force into heat. By changing the impact force, the shock impact force is alleviated, and as the shock absorbing effect by the lead balls increases, the impact repulsion force decreases. As a result, the number of strikes required for the work increases, reducing work efficiency, and in some cases, the worker may have to compensate for the repulsive force of the strikes to pull the hammer up to the desired raised position and then swing it down again. This operation requires this operation, which has the inherent problem of impairing striking workability.

In addition, the lead balls housed in the cylinder become powdered due to the impact when they collide with the wall surface of the cylinder during the hammer strike, and the powder of the lead balls agglomerates.
It is easy to solidify again, and the solidification of such lead ball powder is further accelerated by the heat generated by the lead ball itself due to the impact of the impact, resulting in a blocking phenomenon in which the lead ball becomes a lump-like substance within the cylindrical body. That will happen.

In the case of lead balls that are blocked in this way, the shot prevention function is reduced, and as they move inside the cylindrical body as a lump-like object, the balance is lost and the force acting on the hammer is reduced. Particularly, the force acting on the head part becomes uneven, and as a result, the force acting on each part of the striking surface becomes uneven, resulting in unevenness on the struck surface of the product, etc., and the force acting on the hammer due to the striking repulsion force becomes uneven. When the ball bounces back, the head part shakes, causing problems such as making continuous work difficult.

Means for solving the problem The present invention was made to solve the above problem, and its features are as follows:
The head portion and the handle portion are integrally molded from a predetermined resin material, and lead balls of a predetermined particle size are accommodated in a cylindrical body provided to penetrate the head portion, and the opening of the cylindrical body is closed by a metal cap serving as a striking part, and the end of a core metal embedded in the handle is penetrated and fixed to the cylindrical body, and the hammer is positioned in the cylindrical body on the side of the metal cap. A lead block of a predetermined size is housed and held, thereby maintaining an effective shotless effect as a shock prevention hammer, and exerting a striking force that enables efficient striking operations. A hammer that generates an appropriate impact repulsion force, prevents damage due to the shotless effect, and further prevents lead balls from becoming blocks, allowing for good impact work over a long period of time. I was able to do this.

Embodiment Hereinafter, in order to clarify the present invention more specifically, one embodiment of the present invention will be described in detail based on the drawings.

First, in FIGS. 1 and 2, 2 is a hammer according to the present invention, with a head portion 4 and a handle portion 6.
Both are integrally molded from a predetermined urethane resin, for example, a hard urethane resin material having a hardness (rubber hardness) of about 80 to 100. and,
Inside the head part 4, there is a metal material such as spring steel.
A cylindrical body 8 having a substantially bottomed cylindrical shape is provided so as to pass through the head portion 4 in its longitudinal direction, while a core metal 10 made of heat-treated metal such as steel is provided.
is embedded in the handle 6 along its axial direction. One end of the core bar 10 penetrates the cylindrical body 8 at its approximate center and further projects into the resin portion of the head 4, and the other end extends near the tip of the handle 6. It extends to A narrow flat plate 12 is fixed to the end of the core metal 10 on the side of the handle 6, and serves to prevent the core metal 10 from rotating.

On the other hand, as is clear from Figures 3 and 4,
The cylindrical body 8 has a bottomed cylindrical shape with a thick-walled bottom end rounded and a constriction on the outer periphery of the bottom side, which effectively improves the adhesion with the resin part. It is elevated. The thick bottom portion of the cylindrical body 8 projects outward from the resin portion of the head portion 4 and is exposed to form a sub-striking portion 13 that is one of the striking portions of the hammer 2. Further, the open end side of the cylindrical body 8 similarly protrudes from the resin part, and the peripheral surface of this protruding part is threaded, and a predetermined metal material, such as spring steel, is heat-treated through the threaded part. The main striking part 16 is formed by screwing and bonding a thick-walled metal cap 14 made of a metal cap 14 (via an adhesive as appropriate).

In this way, by screwing the metal cap 14 into the opening of the cylindrical body 8, a cavity 18 is formed within the head portion 4.
has a small diameter space on one side corresponding to the constricted shape of the cylindrical body 8 at the tip, and is divided into two approximately at the center by passing the core metal 10 therethrough. As is especially clear from FIG.
Lead balls 20 up to about mm in size, preferably about 0.5 to 1.0 mm in size, are densely packed and accommodated, and on the other hand,
A lead block 22 of a predetermined size is accommodated in the space 18 on the side of the main striking part 16, one end of which is regulated by a lead ball 20 and a core bar 10, and the other end The end portion is made substantially flush with the open end portion of the cylindrical body 8, and is simultaneously fixed in position by screwing the metal cap 14, which becomes the main striking portion 16. This lead block 22 has a cylindrical shape, and its outer diameter is equal to the cylindrical body 8.
The inner diameter of the hollow space 18 is approximately equal to the inner diameter of the hollow space 18, and the corresponding portion of the cavity 18 is densely filled.

In the hammer 2 having such a configuration, the lead balls 20 filled and housed in the space 18 on the side of the sub-striking part 13 convert a part of the striking force into heat, as in the conventional case. On the one hand, the lead block 22 housed and held on the main striking part 16 side functions as a weight and increases the overall weight of the head part 4. , the impact force of the hammer is effectively improved. In addition, since the shot crease effect is said to be moderate, an effective improvement in impact repulsion force can be seen. Furthermore, by using the lead block 22, when striking with a hammer, the lead ball 20 mainly collides with the surface of the cylindrical body 8 on the main striking part 14 side, that is, the soft end surface of the lead block 22.
Therefore, the occurrence of powdering and blocking of the lead balls 20 itself is effectively suppressed.

On the other hand, the lead block 22
Since it is densely packed and accommodated in the cavity 18 on the side 6 and is held in a fixed position within the cavity, it collides with the inner surface of the cylindrical body 8 when it is struck, rubs against each other, becomes powder, and eventually becomes a block. Of course, there is no risk of this happening, and the striking force acts uniformly on the striking surface of the main striking section 16, providing a good striking surface, while also preventing the balance from being lost during striking and causing wobble, etc. in the head section 2. There will be no more.

As described above, the hammer 2 has a good impact absorption effect as a shock prevention hammer, and the impact force is significantly improved.Moreover, by exerting an appropriate impact repulsion force, it is possible to make a good impact. Work can be carried out efficiently, and this effect is clear from the results of impact force and repulsion force tests conducted by the present inventor, as shown below.

These tests were conducted using three hammers: First, as a comparative example, a shock prevention hammer (sample A) consisting only of a single lead ball was used.
Using a normal steel hammer (sample RO), the product of this invention contained 22.120 g of lead blocks for 20.35 g of lead balls (total weight of lead: 155 g).
A hammer (sample C) was used. At this time, the weight of only the head portion of each hammer was 440 g for sample A, 455 g for sample B, and 465 g for sample C.

In the impact force test, a piston driven by an air cylinder pushes out the impact surface on one side of the hammer (in the case of the hammer of the present invention, the surface on the side of the secondary impact part), and the base of the hammer handle is The hammer is rotated 180 degrees around the end and is rotated 180 degrees to be brought down.The hammer is rotated 180 degrees and brought down.The hammer is rotated 180 degrees around the end and is brought down. It was determined by how much penetration (penetration) was obtained by gripping a rod-shaped member to be hit by a predetermined jig by applying pressure and striking the member with the hammer. In addition, each hammer was operated 10 times.

The striking line graph shown in Figure 6 shows the results of this impact force test, and shows the cumulative amount of impact for each downstroke for each hammer. You can know the total amount of impact for each hammer obtained through the downstroke.

In addition, as a repulsion force test, the repulsion distance of the hammers (heads) was measured when each of the hammers of Samples A, B, and C was allowed to fall naturally at angles of 45°, 90°, and 180°, respectively.

The values shown in the line graph of FIG. 7 are the average values of the repulsion distances obtained from 10 downstrokes for each angle.

As is clear from these FIGS. 6 and 7, the shock prevention hammer according to the present invention has a striking force of
Of course, this is a marked improvement over the conventional shock prevention hammer (sample A), and it also provides better values than the steel hammer (sample B), which does not have a shock prevention effect. It can be seen that sufficient effects are obtained by increasing the weight. In addition, in terms of impact repulsion force, the conventional shock prevention hammer (sample A) is inferior as well as impact force, while in the case of steel hammers (sample B), the impact repulsion distance is generally too large. While it is difficult to perform efficient striking work with either hammer, the shock prevention hammer according to the present invention (sample c) has a repulsion distance of 40 mm to 80 mm, which is the most suitable for the worker. It can be seen that the impact workability of the hammer is good.

As described above, in the present invention, by housing the lead block together with the lead ball in the cylindrical body disposed in the head of the hammer, it has effective impact force and good impact repulsion. However, the present invention is not limited to the description of the embodiments described above.

For example, FIG. 5 is a cross-sectional plan view corresponding to FIG. 4, showing a lead block different from that of the previous embodiment. In this way, by using the relatively long lead block 26 that has the recess 24 that can fit into the core bar 10, the lead block can be more securely fixed within the head section 4, and the lead block can be fixed within the head section. Since the weight of lead contained increases and the total weight of the head itself increases, a shock-proof hammer with stronger striking force is obtained.

Of course, the lead blocks 22 and 26 may be held in the cylindrical body 8 of the head portion 4 in such a way that they do not substantially move freely. It is also possible to substantially prevent the lead block from moving by inserting a lead block and closing the opening of the cylinder with a metal cap.

Also, a metal cap 1 is attached to the open end of the cylindrical body 8.
In the mounting structure of 4, instead of screwing as in the previous embodiment, techniques such as welding can be used, as in the hammer of FIG. 5. It is also possible to use a cylindrical body having both ends open, and to secure metal caps to each opening by an appropriate technique such as screwing or welding to form a cavity within the head.

Furthermore, carbon or graphite powder,
If at least one powder selected from the group consisting of molybdenum disulfide, tank, and calcium stearate, or fluororesin powder is housed in the head together with lead balls and lead blocks, contact on the surface of the lead balls can be avoided. , prevention of lead balls from blocking becomes even more reliable.

In addition, various changes, modifications, improvements, etc. may be made to the present invention based on the knowledge of those skilled in the art without departing from the spirit of the present invention, although they will not be listed one by one.

Effects of the invention As described above, the shock prevention hammer according to the present invention maintains an effective shock prevention function, and
It achieves good impact force and impact repulsion that could not be obtained with conventional anti-shock hammers, and also effectively suppresses lead balls from forming into blocks. To provide a shock prevention hammer that can be used satisfactorily over a long period of time and has an excellent effect due to its simple structure, as it is only made of a block of lead, does not require any special processing, and has no risk of increasing costs. This makes it possible.

[Brief explanation of the drawing]

FIG. 1 is a front view showing one embodiment of the hammer according to the present invention, and FIG. 2 is an A-A in FIG.
3 is a sectional view taken along line BB in FIG. 2, FIG. 4 is a sectional view taken along line C-C in FIG. 3, and FIG. 5 shows another embodiment of the present invention. FIG. 4 is a diagram corresponding to FIG. 4 shown in FIG. FIG. 6 is a graph showing the impact force test effect of the shock prevention hammer according to the present invention and the conventional hammer, and FIG. 7 is a graph showing the impact repulsion force test of the shock prevention hammer according to the present invention and the conventional hammer. It is a graph showing the results. 2: Hammer, 4: Head, 6: Handle, 8:
Cylindrical body, 10: Core metal, 13: Sub-striking part, 14: Metal cap, 16: Main striking part, 18: Blank space, 2
0: Lead ball, 22, 26: Lead block, 24: Recess.

Claims (1)

[Scope of utility model registration request] The head portion and the handle portion are integrally molded from a predetermined resin material, and lead balls of a predetermined particle size are accommodated in a cylindrical body provided to penetrate the head portion, and the opening of the cylindrical body is closed by a metal cap serving as a striking part, and the end of a core metal embedded in the handle is penetrated and fixed to the cylindrical body, and the hammer is positioned in the cylindrical body on the side of the metal cap. A shot prevention hammer characterized by containing and holding a lead block of a predetermined size.