Noise Attenuation Device for an Excavator Breaker

Abstract

The present invention relates to a noise blocking device for an excavator breaker for blocking secondary noise generated between the chisel of the excavator breaker and the object to be crushed. The device of the present invention comprises a ring-type flange coupled to the lower surface of a conventional primary noise blocking device, a bellows made of an elastic material whose upper end is fixed by the ring-type flange and which extends downward to accommodate the chisel inside, a coil spring and sound-absorbing means disposed inside the bellows, and a plurality of spacing members spaced apart in the circumferential direction at the lower part of the bellows and protruding toward the chisel. The upper edge of the bellows is compressed and fixed between the flange and the lower surface of the primary noise blocking device, and the lower end of the bellows extends downward below the lower end of the chisel under normal conditions and contracts elastically in close contact with the surface of the object to be crushed during operation. Multiple spacing members prevent sagging of the bellows and chisel interference during lateral or inclined operation, while allowing external air to enter through the air communication space between the spacing members, thereby preventing the generation of vacuum or high pressure inside the bellows.

Description

Technology Field

[0001] The present invention relates to a noise blocking device for an excavator breaker, and more specifically, to a noise blocking device for an excavator breaker that is connected to the lower part of a primary noise blocking device to block secondary noise generated between the chisel of the excavator breaker and a crushing target such as rock, concrete, or asphalt, unlike a conventional primary noise blocking device.

[0002] The present invention relates particularly to a structure in which an elastic bellows (rubber or soundproof fabric) wraps around a chisel and adheres elastically to the surface of a crushing object, improves noise blocking performance through a coil spring and sound-absorbing means inside the bellows, and prevents sagging of the bellows, interference with the chisel, and changes in internal pressure even during lateral or inclined braking operations through an open gap-maintaining structure at the bottom of the bellows. Background Technology

[0004] Generally, an excavator breaker is equipment mounted on the arm or boom of an excavator to crush rock, concrete structures, asphalt pavement layers, etc. The excavator breaker is configured to reciprocate a piston by hydraulic or pneumatic pressure and transmit the impact force of the piston to a chisel so that the tip of the chisel repeatedly strikes the object to be crushed.

[0005] The noise generated by an excavator breaker can be broadly classified into primary noise, which is generated when the piston strikes the chisel inside the breaker, and secondary noise, which is generated when the tip of the chisel strikes the object to be crushed, such as rock or concrete.

[0006] Previously, primary noise was perceived as relatively large, and accordingly, technology to reduce primary noise through box-type or cover-type sound-absorbing means that surround the breaker body or the front head has been proposed.

[0007] However, once the primary noise is reduced to a certain extent, secondary noise between the chisel and the crushing object, which had not been relatively prominent until now, emerges as a new problem.

[0008] Since secondary noise is generated at the point where the chisel tip directly collides with the object to be crushed, it is difficult to effectively block it with only the existing primary noise blocking device that surrounds the breaker body.

[0009] In addition, breaker operations are not always performed vertically downward, but can be performed horizontally or at an angle to side walls, slopes, or the sides of structures. In this case, the elastic cover or bellows surrounding the chisel may sag downward due to its own weight, the bellows may interfere with the chisel and wear out or tear, and part of the chisel may be exposed to the outside, which may reduce the secondary noise blocking effect.

[0010] Meanwhile, narrowing the bottom of the bellows to be close to the outer diameter of the chisel or configuring it as a sealed type can reduce bellows sagging and chisel exposure to some extent; however, as the chisel reciprocates, the inside of the bellows becomes a vacuum or high-pressure state, which can hinder the chisel's reciprocating motion or cause damage to the bellows.

[0011] Therefore, an open structure is required that allows for the free inflow of outside air while maintaining a stable gap around the chisel. Prior art literature

[0013] Patent Document 1: Republic of Korea Patent Registration No. 10-1025030 Patent Document 2: Republic of Korea Patent Registration No. 10-0928239 The problem to be solved

[0014] The objective of the present invention is to provide a secondary noise blocking device for an excavator breaker that can effectively block secondary noise generated between the chisel of the excavator breaker and the object to be crushed.

[0015] Another objective of the present invention is to provide a secondary noise blocking device that can be simply and securely attached to the lower surface of an existing primary noise blocking device using a ring-type flange.

[0016] Another objective of the present invention is to provide a device in which the lower end of the bellows extends downward below the lower end of the chisel under normal conditions, and elastically contracts while adhering to the surface of the object to be crushed during operation, thereby reducing secondary noise and dust leakage without interfering with the striking operation of the chisel.

[0017] Another objective of the present invention is to provide a device that prevents the bellows from sagging due to its own weight and interfering with the chisel during lateral or inclined braking operations, while ensuring that the lower part of the bellows is not sealed, thereby maintaining air communication between the inside and outside of the bellows.

[0018] Another objective of the present invention is to provide a secondary noise blocking device for an excavator breaker that can improve the shape stability, resilience, durability, and noise blocking effect of the bellows by placing a coil spring and a sound-absorbing material inside the bellows. means of solving the problem

[0020] To achieve the above objective, a secondary noise blocking device for an excavator breaker according to one embodiment of the present invention comprises: a ring-type flange connected around a hole through which a chisel passes on the lower surface of a primary noise blocking device; a bellows made of an elastic material, the upper end of which is fixed by the ring-type flange and which extends downward to accommodate the chisel inside; a coil spring that assists in the expansion and contraction of the bellows; a sound-absorbing means disposed inside the bellows; and a plurality of spacing members coupled to the lower part of the bellows to maintain the gap between the chisel and the bellows.

[0021] The bellows may have a corrugated section in the middle and a cylindrical lower support section without corrugations at the bottom. The outer diameter of the corrugated section and the lower support section of the bellows is formed to be smaller than the central hole of the ring-type flange, and an upper rim section is formed at the top of the bellows, bent outwardly radially to have a diameter larger than the central hole.

[0022] When assembling, the bellows is inserted from top to bottom into the central hole of the ring-type flange, and the upper rim portion is positioned to rest over the central hole. In this state, when the ring-type flange is fastened to the lower surface of the primary noise blocking device by means of bolts and nuts, the upper rim portion is interposed between the ring-type flange and the lower surface of the primary noise blocking device and is compressed and fixed.

[0023] The coil spring is configured to extend together with the bellows to assist in the extension and extension movement of the bellows. The upper and lower ends of the coil spring may be connected to the upper and lower ends of the bellows, or the coil spring may be configured to be positioned within a concave groove of the bellows' corrugation.

[0024] The above sound-absorbing means may include at least one of glass fiber, glass wool, rock wool, foamed polyethylene, or foamed urethane, and preferably is arranged vertically in the space between the coil spring and the chisel so as not to interfere with the expansion and contraction movement of the bellows and the coil spring.

[0025] A plurality of spacing members are attached to the lower support portion of the bellows. The spacing members may not be structured to seal the lower support portion, but may be composed of a plurality of pieces (rubber, fabric protrusions) arranged radially at a certain angle interval in the circumferential direction.

[0026] The above pieces may be composed of rubber or fabric protrusions and are screw-coupled to penetrate the lower support of the bellows from the outside to the inside as a screw structure having a countersunk head, and the end thereof is positioned close to the chisel.

[0027] The internal space defined by the tips of the plurality of spacing members is formed to be slightly larger than the outer diameter of the chisel, thereby allowing the chisel to reciprocate. Additionally, since an air communication space is formed between adjacent spacing members, the inflow of outside air through the lower part of the bellows is free, and the generation of vacuum or high pressure inside the bellows during the chisel's reciprocating motion is prevented.

[0028] Since the above-mentioned spacing members protrude inward from the inner wall of the bellows, they can also function as support means to prevent the sound-absorbing means from escaping to the bottom of the bellows. Accordingly, the sound-absorbing means can be stably maintained inside the bellows without forming a separate inner step. Effects of the invention

[0030] According to the present invention, secondary noise generated between the chisel and the object to be crushed is primarily blocked by an elastic bellows and secondarily absorbed by a sound-absorbing means inside the bellows, so the chisel-rock impact noise, which is difficult to block with only a conventional primary noise blocking device, can be effectively reduced.

[0031] In addition, since the bottom of the bellows extends downward below the normal bottom of the chisel and adheres elastically to the surface of the object to be shredded during operation, the exposure of the chisel to the outside is reduced, and noise and dust generated at the shredding point can be preferentially blocked inside the bellows.

[0032] In addition, the upper edge of the bellows is interposed between the ring-type flange and the lower surface of the primary noise blocking device and is fixed by compression, so the bellows can be firmly joined without adhesive or a complex separate fixing structure.

[0033] In addition, multiple spacing members at the bottom of the bellows are arranged radially around the chisel, thereby limiting the sagging of the bellows during lateral or inclined operation, which prevents interference between the bellows and the chisel and damage to the bellows.

[0034] In addition, since the above-mentioned spacing members do not seal the lower part of the bellows and maintain an air passage space, it is possible to prevent the inside of the bellows from becoming a vacuum or high-pressure state during the reciprocating motion of the chisel. Accordingly, the reciprocating motion of the chisel is maintained smoothly, and the durability of the bellows is improved. Brief explanation of the drawing

[0036] Figure 1 is a conceptual diagram illustrating the primary and secondary noise sources generated in an excavator breaker. Figure 2 is a reference diagram showing the state in which the existing primary noise blocking device surrounds the excavator breaker. FIG. 3 is an exploded perspective view of a secondary noise blocking device for an excavator breaker according to one embodiment of the present invention. FIG. 4 is a cross-sectional view showing a state in which a secondary noise blocking device according to one embodiment of the present invention is coupled to the lower part of a primary noise blocking device. FIG. 5 is an operation diagram showing a comparison between the normal state and the elastic contraction state during operation of a bellows according to one embodiment of the present invention. FIG. 6 is a diagram showing the open spacing structure of the lower part of the bellows and the operation during lateral operation according to one embodiment of the present invention. Specific details for implementing the invention

[0037] Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings. However, it should be understood that the scope of the present invention is not limited thereto.

[0038] In this specification, the embodiments are provided to ensure that the disclosure of the invention is complete and to fully inform those skilled in the art of the scope of the invention, and the scope of the invention is defined only by the claims. Accordingly, in some embodiments, well-known components, well-known operations, and well-known techniques are not specifically described to avoid the invention being interpreted ambiguously.

[0039] The terms used herein are for describing embodiments and are by no means intended to limit the invention. In this specification, the singular form includes the plural form unless specifically stated otherwise in the text. Additionally, components and operations referred to as "comprising (or comprising)" do not exclude the presence or addition of one or more other components and operations.

[0040] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. The following embodiments are examples to aid in understanding the present invention, and the scope of the present invention is not limited thereto.

[0041] Referring to FIGS. 1 and 2, the excavator breaker (10) is configured such that the tip of the chisel (20) crushes the object to be crushed (30) by repeatedly striking the chisel (20) with a piston. At this time, the noise generated between the piston and the chisel (20) can be called primary noise, and the impact sound, crushing sound, and reflection sound generated at the point of contact between the tip of the chisel (20) and the object to be crushed (30) can be called secondary noise.

[0042] The existing primary noise blocking device (40) is configured to surround the breaker body, cylinder, front head, or an adjacent part, and serves to reduce the primary noise generated between the piston and the chisel (20) from being emitted to the outside. However, the primary noise blocking device (40) has difficulty sufficiently blocking secondary noise generated at the point of contact between the lower part of the chisel (20) and the object to be crushed (30).

[0043] Accordingly, the secondary noise blocking device (100) of the present invention is connected to the lower part of the primary noise blocking device (40), particularly around the lower opening (41) through which the chisel (20) passes, and is configured to block the external emission of secondary noise by wrapping the lower part of the chisel (20) and adhering to the surface of the object to be crushed (30).

[0044] FIG. 3 is an exploded perspective view of a secondary noise blocking device for an excavator breaker according to an embodiment of the present invention, and FIG. 4 is a cross-sectional view showing a state in which a secondary noise blocking device according to an embodiment of the present invention is connected to the lower part of a primary noise blocking device,

[0045] The secondary noise blocking device (100) of the present invention is connected to and used on the lower surface of the existing primary noise blocking device (40), and the primary noise blocking device (40) may be a box-type or cover-type structure that surrounds the breaker body, and a lower opening (41) through which a chisel (20) passes is formed on the lower surface.

[0046] The secondary noise blocking device (100) includes a ring-type flange (110), a bellows (120) made of an elastic material, a coil spring (130), a sound-absorbing means (140), a lower support member (150), and a spacing member (151).

[0047] The ring-type flange (110) is an annular plate-shaped member having a central hole, and is fastened to the lower surface of the primary noise blocking device (40) with bolts and nuts through a plurality of bolt fastening holes.

[0048] The central hole of the ring-type flange (110) is formed larger than the outer diameter of the bellows (120) and the lower support (150), so that the bellows (120) can be inserted from top to bottom.

[0049] The above flange (110) may be formed from a metal, alloy, high-strength synthetic resin, or composite material. Preferably, it may be formed from steel or stainless steel to withstand repeated impacts and external working environments. Additionally, the flange (110) may be formed into a circular, square, polygonal, or irregular plate-like structure to correspond to the lower shape of the existing primary noise blocking device (40).

[0050] The elastic bellows (120) can be formed from rubber, synthetic rubber, silicone rubber, urethane, EPDM, NBR, abrasion-resistant elastomer, or a composite thereof.

[0051] The elastic bellows (120) is provided with a corrugated tube in the middle, and due to this corrugated tube structure, the elastic bellows (120) can be compressed and extended along the length direction of the chisel (20) and can be elastically deformed in response to changes in the surface shape of the object to be crushed (30) or the working position of the chisel (20).

[0052] An upper edge portion (123) that is bent outwardly in a radial direction is formed at the top of the bellows (120).

[0053] Since the outer diameter of the upper rim portion (123) is formed to be larger than the central hole of the ring-type flange (110), when the bellows (120) is inserted from top to bottom into the central hole of the ring-type flange (110), the upper rim portion (123) is caught on the upper part of the flange hole.

[0054] In this state, when the ring-type flange (110) is placed against the lower surface of the primary noise blocking device (40) and fastened with bolts and nuts, the upper edge portion (123) is interposed between the ring-type flange (110) and the lower surface of the primary noise blocking device (40) and is compressed and fixed.

[0055] Therefore, the bellows (120) is not easily separated from the flange (110) even with repeated vibrations and shocks during operation.

[0056] The bellows (120) has multiple folds in the middle and a lower support (150) without folds at the bottom.

[0057] Since the lower support portion (150) is a part that can come into direct or indirect contact with the object to be crushed (30), it can be formed thicker than the corrugated portion to ensure durability.

[0058] In addition, a short outer radial edge may be formed at the bottom of the lower support member (150) to increase adhesion with the bedrock.

[0059] During the breaking operation, the tip of the chisel (20) comes into contact with or approaches the object to be crushed (30), and the lower support portion (150) of the elastic bellows (120) comes into contact with the surface of the object to be crushed (30). Subsequently, when the chisel (20) descends further or moves back and forth to strike the object to be crushed (30), the elastic bellows (120) contracts elastically while in close contact with the surface of the object to be crushed (30).

[0060] At this time, the lower support portion (150) of the elastic bellows (120) comes into contact with the surface of the object to be crushed (30) to form a kind of noise-blocking boundary. Accordingly, secondary noise generated at the point of contact between the tip of the chisel (20) and the object to be crushed (30) is suppressed from being directly emitted laterally. In addition, since the elastic bellows (120) surrounds the lower portion of the chisel (20), reflected sound and crushing sound generated around the chisel (20) can be absorbed or attenuated within the bellows.

[0061] The coil spring (130) is positioned vertically inside the bellows (120) to help the bellows (120) expand and contract.

[0062] The coil spring (130) can have its upper and lower ends connected to the upper and lower ends of the bellows (120), or it can be positioned in a concave groove of the bellows (120) and compressed and restored together with the bellows (120).

[0063] The coil spring (130) can be formed from a metal spring, a synthetic resin spring, an elastic wire spring, or a similar elastic support member.

[0064] The sound-absorbing means (140) is placed in the empty space inside the bellows (120).

[0065] The sound-absorbing means (140) may be composed of glass fiber, glass wool, rock wool, ceramic fiber, foamed polyethylene, foamed urethane, foamed rubber, porous sound-absorbing material, or a combination thereof.

[0066] At this time, it is preferable that the sound-absorbing means (140) maintain a certain distance from the outer surface of the chisel (20) so as not to interfere with the reciprocating motion of the chisel (20), or be formed of a very flexible material.

[0067] The sound-absorbing means (140) absorbs noise energy inside the bellows, reduces repeated reflections on the inner wall of the bellows, and reduces the leakage of high-frequency impact sound to the outside generated at the point of contact between the chisel (20) and the object to be crushed (30).

[0068] In the illustrated embodiment of the present invention, the sound-absorbing means (140) is arranged vertically in the space between the coil spring (130) and the chisel (20).

[0069] Accordingly, the sound-absorbing means (140) can absorb secondary noise without interfering with the extension and contraction movement of the bellows (120) and the coil spring (130).

[0070] FIG. 5 is an operational diagram showing a comparison between the normal state and the elastic contraction state during operation of a bellows according to one embodiment of the present invention, wherein the lower end of the bellows (120) in normal state extends further downward than the lower end of the chisel (20).

[0071] When the chisel (20) comes into contact with the object to be crushed (30) during the breaking operation, the lower end of the bellows (120) also comes into contact with the object to be crushed (30) and elastically contracts to the position of the chisel (20).

[0072] At this time, the lower part of the bellows (120) is in close contact with the surface of the object to be crushed (30) to reduce the direct leakage of secondary noise and dust generated between the chisel (20) and the object to be crushed (30) to the outside.

[0073] FIG. 6 is a drawing showing an open spacing structure at the bottom of a bellows and its operation during lateral operation according to one embodiment of the present invention,

[0074] A plurality of spacing members (151) are coupled to the lower support portion (150) of the bellows (120), and the spacing members (151) may be configured in the form of a piece having a countersunk head and are screw-coupled to penetrate the lower support portion (150) from the outside to the inside.

[0075] Multiple spacing members (151) are arranged radially at regular angle intervals with the chisel (20) in the center when viewed from above.

[0076] The end of each spacing member (151) is positioned close to the outer surface of the chisel (20) to allow for the reciprocating motion of the chisel (20), thus serving as a guide between the chisel (20) and the elastic bellows (120).

[0077] In vertical downward operations, since both the chisel (20) and the elastic bellows (120) are generally directed downward due to their own weight, there is no major problem with the elastic bellows (120) wrapping around the chisel (20). However, if a rock or concrete structure is located on the side and the chisel (20) is positioned in a horizontal or inclined direction, the elastic bellows (120) may sag downward due to its own weight.

[0078] In this way, when the bellows (120) sags due to its own weight, the spacing member (151) is supported by the chisel (20) to prevent excessive sagging of the bellows (120) and interference with the chisel.

[0079] In addition, since the plurality of spacing members (151) are spaced apart from each other in the circumferential direction, an air communication space (152) is formed between adjacent spacing members (151).

[0080] Accordingly, the lower part of the bellows (120) is not sealed, and outside air can freely flow into the bellows. Therefore, no vacuum or high pressure is generated inside the bellows even during the continuous reciprocating motion of the chisel (20).

[0081] In addition, since the spacing member (151) protrudes inward from the inner wall of the bellows (120), it can function as a support means to restrict the sound-absorbing means (140) from escaping downward. That is, the downward displacement of the sound-absorbing means (140) can be prevented by the spacing member (151) without forming a separate inner step.

[0082] A plurality of spacing members (151) may be arranged symmetrically or at equal intervals in the circumferential direction. For example, 2, 3, 4, 6, or 8 spacing members (151) may be arranged along the outer circumference of the chisel (20). The number of spacing members (151) may be changed according to the outer diameter of the chisel (20), the inner diameter of the lower part of the bellows, the material of the bellows, the working direction, and the required spacing performance.

[0083] It is preferable that the tips of the plurality of spacing members (151) are arranged at a certain distance from each other without directly contacting the outer surface of the chisel (20). That is, the virtual inscribed space (S) defined by the tips of the plurality of spacing members (151) is formed to be slightly larger than the outer diameter of the chisel (20). Accordingly, the chisel (20) can move smoothly back and forth through the virtual inscribed space (S).

[0084] At the same time, since the virtual inner space (S) is formed to be smaller than the entire lower inner diameter of the elastic bellows (120), the spacing member (151) prevents excessive eccentricity between the chisel (20) and the lower bellows even if the lower support (150) of the elastic bellows (120) sags due to its own weight during lateral or inclined direction work. Therefore, the risk of the lower support (150) of the bellows getting directly stuck or torn by the chisel (20) can be reduced, and the chisel (20) can be maintained within the center area of ​​the lower support (150) of the bellows.

[0085] In addition, since the plurality of spacing members (151) are spaced apart from each other in the circumferential direction, an air communication space (152) is formed between adjacent spacing members (151). The air communication space (152) connects the inner space of the bellows with the outer space.

[0086] Accordingly, the lower part of the elastic bellows (120) substantially reduces the gap with the outer diameter of the chisel (20) without being sealed. Therefore, even if the chisel (20) reciprocates at high speed, the air inside the bellows can freely move to the outside through the air communication space (152), and the pressure inside the bellows is maintained substantially the same as the external pressure.

[0087] As a result, the present invention can simultaneously satisfy two conflicting requirements: the requirement to reduce the gap around the chisel (20) to suppress noise leakage and bellows sagging, and the requirement not to seal the inside of the bellows to prevent pressure changes due to the chisel's reciprocating motion.

[0088] The spacing member (151) is not limited to a countersunk bolt. In other embodiments, the spacing member (151) may be formed of a pin, a rod, a replaceable stopper, an elastic projection, a metal protrusion, a synthetic resin protrusion, or a rubber protrusion. Additionally, the spacing member (151) may be directly connected to the bellows bottom support (150), or may be installed on a separate reinforcing ring, bottom flange, or wear-resistant ring connected to the bottom of the bellows.

[0089] The tip of the spacing member (151) may be formed in a hemispherical, curved, flat, roller-like, or low-friction coating shape. In particular, to reduce wear in the event of accidental contact with the chisel (20), a urethane, rubber, engineering plastic, or low-friction coating layer may be formed on the tip of the spacing member (151).

[0090] Additionally, the spacing member (151) can be configured to adjust the fastening depth. For example, by adjusting the fastening depth of the bolt-type spacing member, the diameter of the virtual inscribed space (S) defined by the tips of the spacing member (151) can be adjusted to match the outer diameter of the chisel (20). Accordingly, the same secondary noise blocking device can be applied to chisels or breakers of different specifications.

[0091] The secondary noise blocking device (100) of the present invention can be manufactured in various lengths. For example, in a device for a large breaker, the length of the elastic bellows (120) can be formed to be approximately 800 mm to 1100 mm, and in a device for a small or medium breaker, it can be formed to be approximately 400 mm to 600 mm. In addition, the diameter of the lower part of the bellows can be formed to be approximately 140 mm to 270 mm or other various dimensions depending on the outer diameter of the chisel and working conditions. These dimensions are exemplary and do not limit the scope of the present invention.

[0092] The operation of the present invention is described below.

[0093] First, the operator positions the flange (110) of the present invention around the lower opening (41) of the existing primary noise blocking device (40). At this time, since the upper edge portion (123) of the elastic bellows (120) has an outer diameter larger than the central hole of the flange (110), it is positioned in a hooked state between the flange (110) and the primary noise blocking device (40). Subsequently, when a coupling means (112), such as a bolt and nut, is fastened, the upper portion of the elastic bellows (120) is firmly fixed by the flange (110).

[0094] Once installation is complete, the elastic bellows (120) extends downward while wrapping around the lower end of the chisel (20), and the bellows lower support (150) is positioned below the tip of the chisel (20) as usual. Therefore, the lower end of the chisel (20) is not exposed to the outside.

[0095] When the braking operation begins, the lower support portion (150) of the bellows contacts the surface of the object to be crushed (30), and the elastic bellows (120) is compressed and restored according to the reciprocating motion of the chisel (20). At this time, since the lower support portion (150) of the bellows remains in close contact with the object to be crushed (30), the secondary noise generated between the chisel (20) and the object to be crushed (30) is reduced from escaping directly to the outside.

[0096] In addition, the coil spring (130) inside the bellows supports the shape of the elastic bellows (120), preventing the bellows from being excessively crushed or twisted during repeated compression and restoration. The sound-absorbing means (140) absorbs noise energy generated or transmitted inside the bellows, thereby further enhancing the noise blocking effect.

[0097] Meanwhile, when braking is performed in a horizontal or inclined direction, the elastic bellows (120) tends to sag downward due to its own weight. At this time, the multiple spacing members (151) of the open spacing member (150) limit excessive eccentricity between the lower part of the bellows and the chisel (20). Thus, it is possible to prevent the lower support part (150) of the bellows from being directly caught in the chisel (20) or torn by the chisel (20).

[0098] At the same time, since an air communication space (152) remains between the multiple spacing members (151), the air flow between the inside and outside of the bellows is not blocked. Therefore, even if the chisel (20) performs high-speed reciprocating motion, no vacuum or high pressure is generated inside the bellows, and the reciprocating motion of the chisel (20) is maintained smoothly.

[0099] As such, the secondary noise blocking device (100) of the present invention has a technical feature in that it does not simply seal the lower end of the chisel, but maintains air circulation while substantially reducing the gap around the chisel through an open gap-maintaining structure. This structure simultaneously achieves multiple effects, such as noise blocking, ensuring chisel reciprocating motion, preventing bellows sagging, and improving durability.

[0101] Although the technical concept of the present invention has been specifically described in preferred embodiments, it should be noted that the aforementioned embodiments are for illustrative purposes only and are not intended to be limiting. It is obvious to those skilled in the art that various modifications and variations are possible within the scope of the technical concept of the present invention, and therefore, it is natural that such modifications and variations fall within the scope of the appended claims. Explanation of the symbols

[0103] 10: Excavator Breaker 20: Chisel 30: Object to be shredded 40: Primary noise blocking device 41: Lower opening 100: Secondary noise blocking device 110: Flange 111: Center hole 112: Connecting means 120: Elastic bellows 123: Edge part 130: Coil spring 140: Sound absorption means 150: Lower support 151: Spacing member 152: Air communication space S: Virtual inscribed space

Claims

Claim 1 A noise blocking device for an excavator breaker for blocking secondary noise generated between the chisel of the excavator breaker and a crushing object, comprising: a ring-type flange coupled around a hole through which the chisel passes on the lower surface of a primary noise blocking device surrounding the excavator breaker; a bellows of an elastic material with its upper end fixed by the ring-type flange and extending downward to accommodate the chisel inside; a coil spring positioned vertically within the bellows at a position corresponding to a corrugated portion formed in the bellows and configured to be compressed and restored together with the bellows; and a sound-absorbing means positioned vertically in the space between the coil spring and the chisel. A noise blocking device for an excavator breaker, comprising a plurality of spacing members arranged at a circumferential distance from the lower portion of the bellows and protruding inwardly in a radial direction toward the chisel, wherein the corrugated portion of the bellows has an outer diameter smaller than the central hole of the ring-type flange, and the upper portion of the bellows is formed at the top portion of the bellows, which is bent outwardly in a radial direction to have a diameter larger than the central hole, and the upper portion is interposed between the ring-type flange and the lower surface of the first noise blocking device and is compressed and fixed, and the lower portion of the bellows normally extends downward below the lower portion of the chisel and elastically contracts while adhering to the surface of the object to be crushed during a breaking operation, and an air communication space is formed between the plurality of spacing members so that outside air can flow into the bellows. Claim 2 A noise blocking device for an excavator breaker according to claim 1, wherein the bellows includes a plurality of corrugated portions in the middle and a lower support portion without corrugations at the bottom, and the lower support portion is formed to be thicker than the corrugated portions. Claim 3 A noise blocking device for an excavator breaker according to claim 2, characterized in that a lower edge portion is formed at the bottom of the lower support portion, bent outwardly in a radial direction to improve adhesion with the surface of the object to be crushed. Claim 4 A noise blocking device for an excavator breaker according to claim 1, characterized in that the coil spring is positioned in a concave groove formed in the corrugated portion of the bellows and configured to be compressed and restored together with the bellows. Claim 5 A noise blocking device for an excavator breaker according to claim 1, characterized in that the upper and lower ends of the coil spring are respectively connected to the upper and lower ends of the bellows. Claim 6 A noise blocking device for an excavator breaker according to claim 1, wherein the sound-absorbing means comprises at least one of glass fiber, glass wool, rock wool, foamed polyethylene, and foamed urethane. Claim 7 A noise blocking device for an excavator breaker according to claim 1, characterized in that the sound-absorbing means is spaced apart from the outer surface of the chisel to allow reciprocating motion of the chisel. Claim 8 A noise blocking device for an excavator breaker according to claim 1, wherein the plurality of spacing members are composed of pieces having a countersunk head and are screw-coupled to penetrate the lower part of the bellows from the outside to the inside. Claim 9 A noise blocking device for an excavator breaker according to claim 8, characterized in that the ends of the plurality of spacing members are close to the outer surface of the chisel but spaced apart from the outer surface of the chisel to allow reciprocating motion of the chisel. Claim 10 A noise blocking device for an excavator breaker according to claim 1, wherein the plurality of spacing members are arranged radially at a certain angle interval with the chisel at the center when viewed from above. Claim 11 A noise blocking device for an excavator breaker according to claim 1, wherein the virtual inscribed space defined by the tips of the plurality of spacing members is formed to be larger than the outer diameter of the chisel and smaller than the inner diameter of the lower part of the bellows, and when the lower part of the bellows is eccentrically deviated toward the chisel side by its own weight due to a lateral or inclined braking operation, at least one tip of the plurality of spacing members is supported on the outer circumference of the chisel, thereby limiting the lower part of the bellows from directly contacting the chisel. Claim 12 A noise blocking device for an excavator breaker according to claim 1, wherein the plurality of spacing members function as supporting means to prevent downward displacement of a sound-absorbing means disposed inside the bellows. Claim 13 A noise blocking device for an excavator breaker according to claim 1, characterized in that a gap is formed between the lower inner diameter of the bellows and the outer diameter of the chisel to allow outside air to flow in, and the pressure inside the bellows maintains equilibrium with the external pressure through the air communication space and the gap.

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