JPS6243836B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a vibration damping type handle device, which is particularly attached to a hand-held power tool such as a hammer drill, a compressed air tool, etc., and the vibration generated in the vibrating hand-held tool is transmitted to the handle. The present invention relates to a vibration damping type handle device that can sufficiently suppress vibration transmission and improve the operability of a vibration tool.

Conventionally, anti-vibration measures for handles of hand-held vibrating tools such as hammer drills have mainly been achieved by interposing anti-vibration rubber between the vibration source of the vibrating tool and the handle.
The method used is to insulate vibrations using anti-vibration rubber.

However, when anti-vibration rubber is used, a force proportional to the vibration speed is transmitted to the handle, making it difficult to block harmful vibrations that can cause occupational accidents such as white wax. Furthermore, since an elastic member such as vibration-proof rubber is used, there is a problem in that the handle is soft to operate, causing the vibrating tool to wobble.

This invention was devised to effectively solve the above-mentioned conventional problems, and an object of the invention is to sufficiently suppress harmful vibrations occurring in the handle of a hand-held vibrating tool such as a hammer drill. Another object of the present invention is to provide a vibration-damping handle device that can improve the operability of this type of vibrating tool.

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

In Fig. 1, reference numeral 1 denotes a connecting part that is connected and fixed to a vibration source (not shown) such as the casing of a power tool that generates harmful vibrations. It is becoming fixed. The connecting portion 1 has arms 3 and 4 integrally extending from both ends of the connecting portion 1 and formed symmetrically. The arms 3 and 4 are made of steel plates with a thickness of about 8 to 10 mm, and are curved so as to be gradually expanded toward the tips of the arms 3 and 4.

First mass bodies 5 and 6 are provided at the tips of arms 3 and 4, respectively. The first masses 5 and 6 have the same mass, are formed in the same shape and are arranged symmetrically on the arms 3, 4. A rod-shaped body 7 having a circular cross section is interposed between the first mass bodies 5 and 6, and the first mass bodies 5 and 6 have through holes 5a through which the rod-shaped body 7 is inserted.
6a are provided respectively.

Male threads are provided at both ends of the rod-like body 7 so that nuts 8, 8 can be screwed into the rod-like body 7. By threading the nuts 8, 8 along the rod-like body 7, the first mass bodies 5 and 6 are screwed together. The distance between the two can be adjusted.

Further, a cylindrical grip member 9 is provided between the first mass bodies 5 and 6 so as to be spaced apart from and cover the rod-shaped body 7. Left end 9a of grip member 9
A coil spring 10 is provided between the first mass body 5 and the first mass body 5.
Further, coil springs 11 are interposed between the right end portion 9b of the grip member 9 and the first mass body 6, and the nuts 8, 8 are moved along the rod-shaped body 7 and the first mass body 5 is moved. , 6 to compress the coil springs 10 and 11, thereby reducing the distance between the coil springs 1 and 1.
The grip member 9 is supported by an elastic force of 0.11.

Annular second mass bodies 12 and 13 are provided on the outer peripheral sides of the left end 9a and right end 9b of the grip member 9, respectively. In order to be able to slide the second mass bodies 12 and 13 along the axial direction of the grip member 9, the left end portion 9a and the right end portion 9b have external threads 9 on their outer peripheral surfaces.
c, 9d, and the second mass body 12,
The inner circumferential surface of 13 is provided with female threads 12a and 13a that engage with male threads 9c and 9d. Also, the second
The mass bodies 12 and 13 are provided with set screws 14 and 15, respectively, in order to fix them to the grip member 9.

Next, the operation of this embodiment will be described.

First, harmful original vibrations are transmitted from a vibration source such as a casing of a power tool to the connecting part 1, and further transmitted to the first mass bodies 5, 6 via the arms 3, 4. The first mass bodies 5 and 6 are excited by the original vibration at substantially the same frequency and phase as the original vibration.

Next, the vibrations of the first mass bodies 5, 6 are transmitted through the coil springs 10, 11 to the left end 9a and the right end 9b of the grip member 9, respectively, while being significantly attenuated. It is transmitted to the second mass bodies 12 and 13 through the section 9b, respectively.

However, when the second mass bodies 12 and 13 are respectively screwed and installed at appropriate symmetrical positions between the left end 9a and the right end 9b, the second mass bodies 1
Vibration nodes can be formed at or near the second mass bodies 12 and 13, and the amplitude of the second mass bodies 12 and 13 can be made extremely small.

This will be explained using the schematic diagram shown in FIG. In the figure, 20 is an elongated metal rod, and the rod 20 has a weight 21 at its center and a tip.
22 is attached. When the base end 20a of this rod 20 is vibrated from side to side, this vibration causes the rod 20 to
are transmitted to the weights 21 and 22, respectively, and the weights 21 and 22 vibrate. However, the weight 21,2
If the mass of the weights 2, the mounting positions of the weights 21 and 22 on the rod 20, the elastic modulus (or thickness) of the rod 20, etc. are appropriately selected, the vibration mode shown in the figure can be achieved. That is, the weight 21 vibrates at the same frequency and phase as the base end 20a,
Since the weight 22 vibrates at the same frequency and in the opposite phase to the weight 21 after the vibration of the weight 21, the weight 21
The vibrations transmitted from the to the weight 22 to the weight 22 are significantly reduced, and the weight 22 vibrates with an extremely small amplitude.

Comparing the vibration system shown in FIG. 2 with the vibration system of the above embodiment, it is found that the weight 21 is connected to the first mass bodies 5, 6
In addition, the weight 22 corresponds to the second mass bodies 12 and 13, respectively, and the portion from the base end 20a of the rod 20 to the weight 21 corresponds to the arms 3 and 4, and the rod 20
The portions from weight 21 to weight 22 correspond to coil springs 10 and 11, respectively.

That is, the original vibration from the vibration source is transmitted to the connecting portion 1,
The vibration is transmitted to the first mass bodies 5 and 6 via the arms 3 and 4, and excites the first mass bodies 5 and 6. At this time, the vibrational energy (kinetic energy) of the original vibration is mainly dissipated as thermal energy (heat generation) caused by internal strain in the arms 3, 4, first mass bodies 5, 6, and coil springs 10, 11. be done. The second mass bodies 12 and 13 vibrate at the same frequency and in substantially opposite phase to the first mass bodies 5 and 6, and the second mass bodies 1
Vibration nodes are formed at and near the second mass bodies 12 and 13, and the second mass bodies 12 and 13 vibrate with extremely small amplitude. Therefore, the vibrations from the vibration source transmitted to the central grip portion 9e of the grip member 9 connected between the second mass bodies 12 and 13 are significantly damped.

Furthermore, since a soft elastic member such as vibration-proof rubber is not used, a vibrating tool such as a hammer drill does not wobble, and this type of tool can be operated accurately. Furthermore, instead of making the entire handle heavier and suppressing the vibration of the handle as in the past, we created a vibration node and attached the grip to it, making it significantly lighter and smaller than conventional handles. It can be made to In addition, the second mass body 1
By shifting the positions of 2 and 13, it is possible to cope with vibrations in a wide frequency range.

In addition, in the above embodiment, the second mass body 1
2, 13 or in the vicinity thereof, the second masses 12, 13 were adjusted by moving along the gripping member 9, while the first masses 5, 6 or The second mass bodies 12 and 13 may be formed so as to be divisible so that they can be adjusted by increasing or decreasing their mass. Furthermore, when the vibrations from the vibration source are intense in the vertical direction, the effect of damping the vibrations in the vertical direction is increased by folding the leaf springs 16 and 17 as arms as shown by broken lines in FIG. Furthermore, coil springs 10, 11
Instead, a leaf spring or the like may be used. Furthermore, the arms 3 and 4, in which the grip member 9 and the second mass bodies 12 and 13 are integrally formed, may be separately fixed to the vibration source. Furthermore, by attaching a cylindrical weight to the center of the rod 7 to make the center of the rod 7 heavier and vibrating the center of the rod 7, the vibration energy of the original vibration supplied from the vibration source can be reduced. The rod-shaped body 7 may also dissipate the energy, thereby reducing the vibration of the first mass bodies 5 and 6 and increasing the vibration damping effect of the grip member 9.

Below, the results of a vibration experiment conducted by attaching the handle device of the above embodiment according to the present invention and a conventional standard handle to a commercially available hand-held electric hammer drill are shown in FIGS. 3 and 4. show.

Both Figures 3 and 4 show that when using a hammer drill,
The acceleration of vibrations transmitted to the handle of the invention and the standard handle is shown. FIG. 3 shows the acceleration of vibration in the vertical direction of the handle, and FIG. 4 shows the acceleration of vibration in the horizontal direction of the handle (radial direction and horizontal direction of the grip member 9). In FIGS. 3 and 4, the horizontal axis is time, the vertical axis is acceleration, and g is gravitational acceleration. vertical movement direction,
As shown in the figure, the handle of the present invention has a remarkable vibration damping effect in both left and right directions. In addition, it has been confirmed that a similar vibration damping effect exists also in the longitudinal direction (the axial direction of the rod-shaped body 7).

As is clear from the above explanation, according to the present invention, the harmful vibrations that cause white wax can be almost completely suppressed, and furthermore, since no anti-vibration rubber etc. are used, the operability of vibrating tools is improved. Moreover, it has excellent effects such as being lightweight and small in size.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of the device according to the present invention, FIG. 2 is a schematic diagram for explaining the vibration damping effect according to the present invention, and FIGS. 3 and 4 are commercially available hand-held devices. 2 is a graph showing the acceleration of vibration transmitted to the handle when the handle of the present invention and the conventional standard handle are respectively attached to the electric hammer drill of FIG. In the figure, 3 and 4 are arms, 5 and 6 are first mass bodies, 7 is a rod-shaped body, 9 is a grip member, 10 and 11 are resilient members, and 12 and 13 are second mass bodies.

Claims (1)

[Claims] 1 A pair of arms connected to a vibration source and extending from this, first mass bodies provided at the tips of the arms, and a rod-shaped body interposed between these first mass bodies. a grip member provided so as to cover the rod-shaped body while being spaced from the rod-shaped body; and a resilient member interposed between the grip member and each of the first mass bodies to support the grip member. and a pair of second mass bodies provided on both sides of the grip member.