JPH0338076B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a chisel striking device for efficiently crushing concrete, rocks, or paved road surfaces.

[Prior Art] A so-called concrete breaker, which is often seen at road construction sites, uses a hose to guide compressed air generated by a compressed air generator to the breaker body, and uses the expansion force of this compressed air to move a piston hammer up and down. The chisel is configured to strike the chisel. However, this concrete breaker
There is a large energy loss when the compressed air flows into the hose or when it expands within the breaker body and is discharged outside the breaker body, so the breaker body generates less energy than the energy required to generate the compressed air. The amount of work that could be done was extremely small, and the efficiency was extremely low. In addition, a compressed air generator and a long hose to guide the compressed air from this to the breaker body are required, making the whole thing large-scale. It was limited to relatively large areas. In order to eliminate the above-mentioned drawbacks of conventional concrete breakers, the inventor of the present application has developed a portable chisel that can efficiently perform work with an extremely low-output power source that is attached directly to the main body or placed nearby. Various types of striking devices have been proposed (for example, see Utility Model Publication No. 1111 of 1983). First, the basic structure of the above-mentioned conventional chisel striking device will be explained based on the conventional example shown in FIG. A movable cylinder 2 is fitted into an outer cylinder 1 formed using a long cylindrical body so as to be able to slide back and forth. Driven to reciprocate in the axial direction. The crankshaft 4 of the crank mechanism 3 is connected to a prime mover (not shown) directly attached to the upper part of the main body via a deceleration mechanism, or to a separate prime mover (not shown) via a flexible transmission shaft. connected. The movable cylinder 2 has a sealed upper part and a through hole 5 at the lower part, and the lower striking rod 7 of the piston hammer 6 is tightly fitted into the interior of the cylinder so as to be able to reciprocate in the axial direction. is configured to protrude from the through hole 5 and strike the top 8a of the chisel 8. On the other hand, the chisel 8 is supported at the lower part of the main body so as to have the same axis as the movable cylinder 2 or the piston hammer 6. Regarding the support structure of this chisel 8, the top part 8a is attached to the outer cylinder 1 more than necessary.
It is necessary to provide means to prevent the metal from entering the inside and falling out downward. That is, if the top of the chisel 8 protrudes too far into the outer cylinder 1, the piston hammer 6 will hit the chisel 8 on its way down, making it impossible to apply a sufficient impact to the chisel, and the piston hammer 6 This is because the timing of the reciprocating motion relative to the movement of the movable cylinder 2 may be out of order, which may cause the movement of the movable cylinder 2 to stop. In the striking device according to this example, the above-mentioned means are provided with the following configuration. A small annular chamber 11 defined by the upper projecting ring 9 and the upper surface of the lower holder 10 is provided in the chisel support section at the bottom of the main body, and the collar 12 provided at the middle part of the chisel 8 reciprocates a certain distance within this annular small chamber 11. It is made so that it can be done. This prevents the collar 12 from coming into contact with the protruding ring 9 and preventing its upward movement, thereby preventing the chisel 8 from moving upward more than necessary and causing its top 8a to protrude too far into the outer cylinder 1. On the other hand, the collar 12 comes into contact with the upper surface of the lower holder 10 to prevent its downward movement, thereby preventing the chisel 8 from falling off. Furthermore, it is necessary to interpose a compression elastic body within the main body to elastically urge the chisel 8 to protrude outward. In the above-mentioned percussion device, a chamber 1
4, that is, the lower surface 13a of the partition wall 13 and the chisel 8
A compression coil spring 16 is interposed between the large diameter portion 15 formed above the flange 12 provided in the middle portion of the flange 12 . By providing the compression coil spring 16, when the striking device is operated, it supports the weight of the striking device so that the collar 12 is located in the middle of the stroke inside the annular chamber 11, and the chisel 8 is moved into the piston hammer. When the chisel 6 strikes, it is possible to prevent the impact reaction force from the object to be crushed by the chisel 8, that is, a hard rock, from being directly transmitted to the main body. Also, while striking the object to be crushed, the sum of the reaction force that tends to lift the main body upward when the piston hammer 6 strikes the chisel 8 downward, and the elasticity of the compression coil spring 16. However, due to the balance with the weight of the device, the main body rises slightly relative to the object, and as mentioned above, the flange 12 of the chisel 8 is located at the middle of the stroke inside the annular chamber 11. The moment 8 smashes the object, the above reaction force disappears, and the next moment the main body loses its weight and
The movable cylinder 2 tends to sink rapidly due to the downward reaction force caused by being pulled upward by the crank mechanism. The above compression coil spring 16
is also necessary to prevent the collar 12 from colliding with the protruding ring 9 at this time.

[Problem to be solved by the invention]

However, the above conventional chisel striking device has the following problems. First, since the compression coil spring 16 is interposed so as to be wrapped around the chisel 8, the overall length of the compression coil spring 16 must be considerably long in order to obtain a sufficient compression stroke and sufficient elastic force. I have to make it a thing. For this reason, the axial length of the main body becomes considerably long, and the length of the chisel etc. also becomes long, making it impossible to reduce the size and weight of the device. Second, as described above, the space for interposing the compression coil spring 16, that is, the chamber 14;
Since the above-mentioned small chambers 11 are provided separately above and below to cooperate with the collar 12 provided on the chisel 8 to define the amount of axial movement of the chisel 8, the axial length of the main body is further increased. . In order to operate the chisel striking device without any trouble, it is necessary to provide a means for regulating the amount of vertical movement of the chisel as described above, and a means for elastically biasing the tip of the chisel so as to protrude outward. A means to store it is essential. For this reason, in the chisel striking device of the conventional structure as described above, it is impossible to shorten the axial length of the device body to make the device smaller and lighter, and at the same time to improve usability. It was hot. In particular, in order to obtain high output, the movable cylinder 2
Considering that it is necessary to increase the vertical movement amount of the piston hammer 6 by increasing the length of the piston hammer 6, it is impossible to shorten the axial length of the device main body with the above conventional structure. The present invention was devised under the above-mentioned circumstances, and solves the above-mentioned conventional problems. By improving the arrangement structure of the compression elastic body, the axial length of the chisel support section at the bottom of the device body was shortened at once, making the entire device smaller and lighter, and further increasing the output. The object is to provide a chisel striking device that can be improved.

[Means to solve the problem]

In order to solve the above problems, the present invention takes the following technical measures. That is, the present invention provides a top part of a chisel whose upper shaft part is supported by a boss part having a predetermined axial length provided at the lower part of a long cylindrical outer cylinder so as to be slidable back and forth in the axial direction. In the chisel striking device configured to strike the chisel with a piston hammer reciprocatingly driven to apply an impact force in the axial direction of the outer cylinder to the chisel, Forming a reduced diameter part smaller than the outer diameter of the outer cylinder,
Further, a compression elastic body is provided so as to surround the reduced diameter part, and the lower end thereof is engaged with the large diameter part formed in the middle part of the chisel, while A holder is provided which is extended into a cylindrical shape so as to cover the outside of the compression elastic body and has a bottom portion with a through hole, and a portion of the chisel protrudes downward from the large diameter portion of the chisel from the through hole. Accordingly, the through hole of the holder is configured to function as a stopper for preventing the chisel from slipping out from the boss portion.

Effects and Effects of the Invention In the present invention, the lower outer diameter of the boss portion through which the chisel is inserted and supported is reduced to form a reduced diameter portion, and the reduced diameter portion is surrounded. A compression elastic body is arranged to elastically support the chisel. In other words, the boss portion and the compression elastic body are not arranged above and below each other in the axial direction as in conventional striking devices, but are arranged so as to overlap in the radial direction of the chisel. . Therefore, the vertical length of the mounting structure for the compression elastic body can be significantly shortened. Moreover, when a compression coil spring is used as the compression elastic body, for example, the winding diameter can be increased, so it is possible to employ a coil spring that has stable elastic force and durability. Furthermore, since the compressive elastic body is arranged to surround the boss, the upper end of the movement range of the chisel is defined by bringing the lower end surface of the boss into contact with the large diameter part of the chisel. On the other hand, the lower end of the range of movement of the chisel can be defined by bringing the peripheral edge of the through hole of the holder extending from the outer cylinder into contact with the lower surface of the large diameter. For this reason, like a conventional striking device, there is a chamber for interposing a compression elastic body (compression coil spring), and a small chamber for accommodating the large diameter part (tsuba) of the chisel and defining its vertical movement range. It is no longer necessary to separately provide the upper and lower parts, and the vertical length of the apparatus main body can be further shortened. Furthermore, since the structure of the support portion of the chisel is shortened in the axial direction, it is also possible to extend the length of the movable cylinder accordingly. That is, by lengthening the travel stroke of the piston hammer, it is possible to increase the output of the device. As described above, according to the present invention, the length of the chisel striking device can be shortened while maintaining its performance. As a result, it is possible to make the device smaller and lighter, and the entire device becomes more compact and easier to use.
It is also possible to reduce costs by reducing weight.

[Explanation of Examples]

Embodiments of the present invention will be specifically described below with reference to FIGS. 1 and 2. In these figures, members having the same or similar functions as those of the conventional chisel striking device shown in FIG. 3 are given the same reference numerals as in FIG. 3. In the chisel striking device according to the present embodiment, an outer cylinder 1 is formed inside the cylindrical main body, and a movable cylinder 2 is fitted inside this so as to be able to reciprocate vertically. The piston hammer 6 fitted into the inside of this constitutes a so-called striking mechanism A. The striking mechanism A in the striking device is generally composed of a driving body B that reciprocates, and a driven body C that follows this driving body B via an elastic body such as air. By accelerating the driven body C using the elastic force of the elastic body such as air generated by the delayed movement, and thereby hitting the target to be hit at a much higher speed than the reciprocating speed of the driving body B. , so that the desired impact energy can be obtained. In addition to using air as in this embodiment as the elastic body, a coil spring or the like may also be used. In this embodiment, the movable cylinder 2 is used as a driving body B that is driven via a crank mechanism 3, and the piston hammer 6 is used as a driven body C. On the contrary, it is also possible to connect a piston-shaped driving body to a crank mechanism, fit a cylindrical driven body C onto the driving body, and make the air sealed between them function as an elastic body. In addition, in this embodiment, a jacket body 1' is provided on the outside of the outer cylinder 1 to form a double cylinder, and ventilation holes 17 and 1 are provided on the upper and lower sides of the outer cylinder 1.
8, the area above the movable cylinder 2 in the outer cylinder 1 and the movable cylinder 2
It communicates with the lower part to reduce the resistance to the vertical movement of the movable cylinder 2. A striking rod 7 is integrally formed at the lower part of the piston hammer 6, and when the piston hammer 6 moves downward at high speed following the movement of the movable cylinder 2,
This striking rod 7 projects downward from a through hole 5 formed in the lower part of the movable cylinder 2 and strikes the top 8a of the chisel 8. The interior of the movable cylinder 2 is divided by the piston hammer 6 into an upper pneumatic chamber 19 and a lower pneumatic chamber 20. The upper and lower air pressure chambers 19, 20 are alternately compressed by the inertia lag of the piston hammer 6, and the air elastic force generated thereby accelerates the movement of the piston hammer. In this embodiment, an appropriate number of through holes 21 are provided in the side wall of the movable cylinder 2, and by communicating the upper air pressure chamber 19 with the outside air when the piston hammer 6 moves downward, the vacuum pressure in the upper air pressure chamber 19 is reduced by the piston. While preventing the hammer 6 from interfering with acceleration during its downward movement,
By communicating the lower air pressure chamber 20 with outside air when the piston hammer 6 moves upward, the lower air pressure chamber 2
The structure is such that zero vacuum pressure does not hinder the upward movement of the piston hammer 6. The present invention improves the chisel support structure described below and the arrangement structure of the compression elastic body (compression coil spring) for giving downward elasticity to the chisel, thereby improving the upper and lower chisel support parts at the lower part of the striking device main body. The purpose is to shorten the length, and therefore, the type of striking mechanism A is not limited to that described above. As shown in FIG. 1, a boss portion 22 of a predetermined length is formed at the bottom of the outer cylinder 1 and has a support hole 22a that communicates the inside of the outer cylinder 1 with the outside. The upper shaft part 8b of the chisel 8 is supported in the support hole 22a so as to be able to slide vertically and reciprocally. Further, this boss portion 22 is formed with a reduced diameter portion 22b whose lower outer diameter is reduced to be smaller than the outer diameter of the outer cylinder 1. On the other hand, the chisel 8 is supported by the support hole 22a so as to have the same axis as the movable cylinder 2 or the piston hammer 6, and the top portion 8a thereof is configured to be able to slightly protrude into the outer cylinder 1. ing. Further, a large diameter portion 15 is formed in the middle portion of the chisel 8 to be engaged with the lower end of a compression coil spring 16, which will be described next. Reduced diameter portion 22 formed below the boss portion 22
A compression coil spring 16 is inserted into the sleeve so as to surround it. The compression coil spring 16 has an upper end 16b in contact with a proximal stepped wall of the reduced diameter part of the boss part 22, and a lower end 16a in the large diameter part formed at the middle part of the chisel 8. 15 through a collar 25 or the like. As a result, the chisel 8 is elastically biased downward. Further, in this embodiment, a cylindrical holder 10 extends from the lower outer periphery of the outer cylinder 1 into a cylindrical shape so as to cover the outside of the compression coil spring 16, and has a bottom portion with a through hole 27. is provided. A portion of the chisel 8 below the large diameter portion 15 projects outward from the through hole 27. The inner diameter of the through hole 27 is set to be smaller than the large diameter portion 15 of the chisel 8, and the lower surface of the large diameter portion 15 is set to the through hole 27.
The chisel 8 is prevented from coming out of the boss portion 22 by coming into contact with the peripheral edge of the boss portion 22 . That is, the through hole 27 is configured to function as a stopper 27a that prevents the chisel 8 from coming out of the boss portion 22. Note that if this holder 10 is configured to be attached by screwing into the outer circumference of the lower part of the outer cylinder 1, for example,
Convenient for assembly. Note that the lower end 16a of the compression coil spring 16
As shown in FIG. 2, the diameter of the winding may be made small so that it directly engages with the large diameter portion 15 of the chisel 8. This prevents the collar 25 from chattering. Further, as shown in FIG. 2, the upper end 1 of the winding wire of the compression coil spring 16
6b is curved so as to protrude inward, and this protruding portion is engaged with the engagement groove 26 formed on the upper outer periphery of the reduced diameter portion 22b of the boss portion 22.
The compression coil spring 16 does not flicker around the outer periphery of the reduced diameter portion 22b, and stable elasticity can be obtained. As described above, in the chisel striking device according to this embodiment, the boss portion 22 and the compression coil spring 1
6 are not located above and below each other in the axial direction,
They are arranged so as to overlap in the radial direction of the chisel 8. Therefore, the vertical length required to attach the compression coil spring 16 can be significantly shortened. Moreover, compared to the conventional structure, the compression coil spring is 1
Since the winding diameter of 6 can be increased, it is possible to use a compression coil spring that has stable elastic force and durability. Further, since the compression coil spring 16 is arranged to surround the boss portion 22, the lower end surface 22c of the boss portion 22 and the upper surface of the large diameter portion 15 of the chisel 8 or the collar 25 are brought into contact with each other. While the upper end of the movement range of the chisel can be defined, by bringing the peripheral edge of the through hole 27 of the holder 10 extending from the outer cylinder 1 into contact with the lower surface of the large diameter part 15. The lower end of the movement range of the chisel 8 can be defined. For this reason, as in the conventional striking device, the chamber for interposing the compression coil spring 16 and the small chamber for accommodating the large diameter part (flange) of the chisel and defining its vertical movement range are arranged vertically. There is no need to provide separate parts, and the vertical length of the device main body can be further shortened. Furthermore, since the structure of the support portion of the chisel is shortened in the vertical direction, it is also possible to extend the length of the movable cylinder accordingly. That is, by lengthening the travel stroke of the piston hammer, it is possible to increase the output of the device. As described above, according to the present invention, the length of the chisel striking device can be shortened while maintaining its performance. As a result, the device can be made smaller and lighter, the entire device becomes more compact and easier to use, and further, costs can be reduced by reducing the weight. The present invention is not limited to the embodiments described above. In the embodiment, a compression coil spring 16 is used as the compression elastic body, but a compression elastic body formed of rubber or resin into a cylindrical shape may also be used. Furthermore, when the large diameter portion 15 or the outer circumference of the collar 25 is brought into contact with the inner circumference of the holder 10 in a sealed manner,
Air sealed in the annular space 24 formed by the holder 10, the boss portion 22, and the large diameter portion 15 functions as a compressible elastic body.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIG. 2 is a sectional view of a main part of another embodiment, and FIG. 3 is a sectional view showing a conventional example. 1... Outer cylinder, 6... Piston hammer,
8...Chisel, 8a...Top part, 8b...Upper shaft part (of the chisel), 10...Holder, 15...Large diameter part (of the chisel), 22...Boss part, 22b...Reduced diameter part, 16...
... Compression elastic body (compression coil spring), 27 ... Through hole,
27a...stoppa.

Claims (1)

[Scope of Claims] 1. The top of a chisel, the upper shaft of which is supported so as to be able to reciprocate in the axial direction by a boss having a predetermined axial length provided at the lower part of the long cylindrical outer cylinder, is attached to the outer cylinder. In the chisel striking device configured to strike with a piston hammer reciprocally driven internally and apply an impact force to the chisel in the axial direction of the outer cylinder, the boss portion is provided with a lower outer diameter thereof. forming a reduced diameter portion smaller than the outer diameter of the outer cylinder;
Further, a compression elastic body is provided so as to surround the reduced diameter part, and the lower end thereof is engaged with the large diameter part formed in the middle part of the chisel, while A holder is provided which is extended into a cylindrical shape so as to cover the outside of the compression elastic body and has a bottom portion with a through hole, and a portion of the chisel protrudes downward from the large diameter portion of the chisel from the through hole. A chisel striking device, characterized in that the through hole of the holder is configured to function as a stopper for preventing the chisel from slipping out of the boss portion.