Excavated soil scattering prevention equipment

Abstract

To provide an excavated soil scattering prevention tool capable of reducing the time required for curing work, as well as the time required for preparation work during excavation, and capable of being stored and transported without being bulky.SOLUTION: The object is an excavated soil scattering prevention tool 1 which is attached to a down-the-hole hammer 2 including a hollow cylindrical hammer case 3 and catches excavated soil blown upward along an outer surface of the hammer case 3. It comprises a main body sheet 12 that is formed into a partially annular shape with a flexible sheet body, and is attached to the hammer case 3 in an umbrella-like position expanding downward, with an arcuate edge 16 on a small diameter side being in contact with an outer peripheral surface of the hammer case 3, and a stopper 13 for holding the main body sheet 12 attached to the hammer case 3 in position.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a device for preventing excavated soil from scattering in a down-the-hole hammer excavation method. [Background technology]

[0002] In down-the-hole hammer drilling methods, excavated soil, along with the air used to operate the hammer, is forcefully blown upward along the outer surface of the hammer from the gap between the hole being drilled and the down-the-hole hammer. This requires extensive curing of buildings and other structures around the excavation site, which requires a great deal of time and effort. To reduce the time required for curing, Patent Document 1 (title of invention: Drilling Device) discloses, for example, a device to prevent excavated soil from scattering, which prevents excavated soil from scattering. The drilling device of Patent Document 1 includes a unit main body that includes a cylindrical outer wall, a ceiling wall that covers the upper end of the outer wall, and a cylindrical wall attached to the ceiling wall, and an adjustment adapter that is inserted into the cylindrical wall and through which the down-the-hole hammer is inserted. The adjustment adapter has a cylindrical body and a plurality of adjustment ribs extending radially outward on the outer peripheral surface of the cylindrical body, and the extension dimension of the adjustment ribs can be adjusted to correspond to the dimensional difference between the outer diameter of the cylindrical body of the adjustment adapter and the inner diameter of the cylindrical wall of the unit main body. The excavated soil scattering prevention device also serves as a contact prevention device for the down-the-hole hammer during excavation work.

[0003] By using the excavated soil scattering prevention device of Patent Document 1, the excavated soil blown upward along with the operating air can be caught by the outer wall, ceiling wall, and adjustment adapter, and the excavated soil can be reliably prevented from scattering around. As a result, the area that needs to be cured is smaller than when the excavated soil scattering prevention device is not used, and the effort and time required for the curing work can be significantly reduced. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-112227 Summary of the Invention [Problem to be solved by the invention]

[0005] Although the material of the excavated soil scattering prevention device in Patent Document 1 is not specified, it is believed to be made of a rigid body such as metal, since it also serves as a touch prevention device. Therefore, the heavy excavated soil scattering prevention device must be installed and removed from the ground every time excavation work is performed, which requires a lot of time and effort. Furthermore, after installing the excavated soil scattering prevention device on the ground, it is necessary to insert a down-the-hole hammer into the adjustment adapter and adjust the adjustment rib, which also requires a lot of time and effort. Furthermore, the excavated soil scattering prevention device in Patent Document 1 is bulky, which has the disadvantage of being difficult to store and transport.

[0006] To provide an excavated soil scattering prevention device that can reduce the time required for curing work as well as the time required for preparation work at the time of excavation, and can be stored and transported without being bulky. [Means for solving the problem]

[0007] The present invention relates to an excavated soil scattering prevention device 1 that is attached to a down-the-hole hammer 2 that includes a hollow cylindrical hammer case 3, and that catches excavated soil that is blown upward along the outer surface of the hammer case 3. The excavated soil scattering prevention device 1 is made of a flexible sheet body formed in a partially annular shape, and is equipped with a main body sheet 12 that is attached to the hammer case 3 in an umbrella-like position that spreads downward, with an arc edge portion 16 on the small diameter side in contact with the outer circumferential surface of the hammer case 3, and a stopper 13 that holds the main body sheet 12 in place when attached to the hammer case 3.

[0008] The stopper 13 is fixed along the arc edge 16 on the small diameter side of the main body sheet 12 and is composed of a plurality of attached magnets 19 that are magnetically attracted to the hammer case 3.

[0009] The main body sheet 12 is provided with a connecting means 23 for connecting the overlapping portion 22 of the main body sheet 12 when attached to the hammer case 3.

[0010] The connecting means 23 is composed of an adhesive 24 arranged on the upper surface of the main sheet 12 located on the lower side of the overlapping portion 22 of the main sheet 12, and a connecting magnet 25 arranged on the lower surface of the main sheet 12 located on the upper side of the overlapping portion 22 of the main sheet 12 and magnetically attracted to the adhesive 24.

[0011] The main body sheet 12 is provided with a shape retaining means 30 for retaining the shape of the main body sheet 12 wound around the hammer case 3 in an umbrella shape.

[0012] The shape-retaining means 30 is composed of a flexible metal wire rope 31 fixed along the partially annular shape of the main body sheet 12. [Effects of the Invention]

[0013] In the excavated soil scattering prevention device of the present invention, the main body sheet 12 is formed into a partially annular flexible sheet, and the main body sheet 12 is attached to the hammer case 3 in a downwardly flared umbrella-like position, with the arcuate edge 16 on the smaller diameter side in contact with the outer circumferential surface of the hammer case 3. When the main body sheet 12 is attached to the hammer case 3 in this downwardly flared umbrella-like position, even if the excavated soil is blown upward along the outer surface of the down-the-hole hammer 2 together with the operating air during excavation work, the excavated soil is caught by the main body sheet 12, thereby effectively preventing the excavated soil from being accidentally scattered around. As described above, by using the excavated soil scattering prevention device 1 of the present invention, the curing area prior to excavation work can be made smaller, significantly reducing the time and effort required for curing work.

[0014] Furthermore, if stoppers 13 are provided for holding the position of the main body sheet 12 attached to the hammer case 3, the excavated soil scattering prevention device 1 can be easily attached to the hammer case 3 simply by wrapping the partially annular main body sheet 12 around the hammer case 3 and holding its position relative to the hammer case 3 with the stoppers 13, and the excavated soil scattering prevention device 1 can be easily separated from the hammer case 3 simply by releasing the stoppers 13 in the reverse order. Therefore, according to the present invention, the work of installing (mounting) the excavated soil scattering prevention device 1 on the hammer case 3 and the work of removing (separating) the excavated soil scattering prevention device 1 from the hammer case 3 are easy, and the time required for preparation work during excavation and the time required for removal work after excavation can be significantly reduced.

[0015] Furthermore, in the excavated soil scattering prevention device of the present invention, the main body sheet 12 is formed into a partially annular shape using a flexible sheet, so that the volume of the excavated soil scattering prevention device 1 can be made compact when not in use by, for example, rolling the main body sheet 12 into a cone shape or folding it multiple times. Therefore, the excavated soil scattering prevention device 1 can be stored and transported without becoming bulky.

[0016] If the stopper 13 is fixed along the arc edge portion 16 on the small diameter side of the main body sheet 12 and is composed of a plurality of attachment magnets 19 that are magnetically attracted to the hammer case 3, the excavated soil scattering prevention device 1 can be attached simply by wrapping the main body sheet 12 around the outer periphery of the hammer case 3 while attracting the attachment magnets 19 to the hammer case 3 so that the arc edge portion 16 on the small diameter side of the main body sheet 12 comes into contact with the hammer case 3. In addition, the excavated soil scattering prevention device 1 can be separated simply by pulling the main body sheet 12 as if to peel the attachment magnets 19 from the hammer case 3.

[0017] If the main body sheet 12 is provided with connecting means 23 for connecting the overlapping portions 22 of the main body sheet 12 when attached to the hammer case 3, the ends of the main body sheet 12 can be integrated to eliminate the formation of gaps in the overlapping portions 22. This makes it possible to prevent excavated soil from scattering through the gaps, thereby providing a more reliable excavated soil scattering prevention device.

[0018] When the connecting means 23 is configured to include an adhesive 24 arranged on the upper surface of the main sheet 12 located on the lower side of the overlapping portion 22 of the main sheet 12, and a connecting magnet 25 arranged on the lower surface of the main sheet 12 located on the upper side of the overlapping portion 22 of the main sheet 12 and magnetically attracted to the adhesive 24, the overlapping portions 22 of the main sheet 12 can be connected and integrated by a simple operation of simply attracting the connecting magnet 25 to the adhesive 24.

[0019] When the main body sheet 12 is provided with a shape-retaining means 30 for maintaining the shape of the main body sheet 12 wound around the hammer case 3 in an umbrella shape, deformation of the main body sheet 12 when receiving excavated soil can be suppressed, so that the excavated soil can be received accurately and prevented from scattering.

[0020] If the shape-retaining means 30 is composed of a flexible metal wire rope 31 fixed along the annular shape of the main body sheet 12, the main body sheet 12 can be expanded by utilizing the elastic restoring force of the metal wire rope 31, thereby maintaining the umbrella-shaped shape of the main body sheet 12 with a simple configuration. Furthermore, since the metal wire rope 31 bends and extends in response to changes in the shape of the main body sheet 12, it can be freely adapted to the shape of the main body sheet 12, such as when the main body sheet 12 is expanded flat, when the main body sheet 12 is wound around the hammer case 3, or when the main body sheet 12 is rolled into a conical shape. [Brief explanation of the drawings]

[0021] [Figure 1]4 is a longitudinal cross-sectional view of the excavated soil scattering prevention device according to the embodiment of the present invention, taken along line AA in FIG. 3. FIG. [Figure 2] FIG. 1 is a side view showing an excavation method using a down-the-hole hammer. [Figure 3] FIG. 1 is a cross-sectional plan view of a down-the-hole hammer with an excavated soil scattering prevention device attached. [Figure 4] FIG. 2 is a plan view showing the excavated soil scattering prevention device unfolded in a plane. [Figure 5] FIG. 5 is a cross-sectional view taken along line BB in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0022] (Embodiment) Figures 1 to 5 show an embodiment of an excavated soil scattering prevention device according to the present invention. In this embodiment, the terms "front, back, left, right, up, down" refer to the crossed arrows shown in Figures 1, 3, and 4 and the symbols near each arrow. As shown in Figure 2, the excavated soil scattering prevention device 1 is attached to a down-the-hole hammer 2. The down-the-hole hammer 2 includes a hollow cylindrical hammer case 3 and a hammer body 4 incorporated into the hammer case 3. The hammer body 4 includes a bit 5 for excavating the ground and a piston 6 for driving the bit 5. The bit 5 protrudes downward from the lower end of the hammer case 3, and the piston 6 is disposed inside the hammer case 3. The piston 6 is driven up and down by compressed air supplied from a compressor 7. The up and down movement of the piston 6 is transmitted to the bit 5, causing the bit 5 to vibrate up and down. The down-the-hole hammer 2 rotates the entire device to drill a hole while crushing the ground with the vibration of the bit 5.

[0023] The down-the-hole hammer 2 is used for drilling while being suspended and supported by a crane device 9 mounted on the bed of a work vehicle 8. After driving the piston 6, the air is discharged from the bottom end of the hammer case 3. The diameter of the hammer case 3 is set smaller than the diameter of the bit 5, and the excavated soil produced by drilling, together with the air discharged from the bottom end of the bit 5, is discharged to the ground through the gap between the hole being drilled and the hammer case 3 (down-the-hole hammer 2). At this time, the air supplied to the piston 6 is pressurized, so the excavated soil is blown forcefully upward from the gap along the outer surface of the hammer case 3. To prevent this blown excavated soil from scattering around, the down-the-hole hammer 2 is fitted with an excavated soil scattering prevention device 1 of this embodiment.

[0024] As shown in Figure 4, excavated soil scattering prevention device 1 includes a main body sheet 12 formed in a partially annular shape and wrapped around hammer case 3, and a retaining means (stopper) 13 for holding main body sheet 12 in place when wrapped around hammer case 3. Main body sheet 12 is made of a flexible sheet body in which both sides of a base fabric are coated with resin, and outer and inner fabrics 14 and 15, cut into the same partially annular shape, are sewn together at arc-shaped edge 16 on the small diameter side, arc-shaped edge 17 on the large diameter side, and straight edges 18 / 18 connecting both arc-shaped edges 16 / 17 (see Figure 5). As shown in Figure 1, excavated soil scattering prevention device 1 is attached to hammer case 3 so that main body sheet 12 is wrapped around one or more times in a downwardly spreading umbrella shape (in a downwardly spreading umbrella-shaped position) with arc-shaped edge 16 on the small diameter side of main body sheet 12 in contact with the periphery of hammer case 3. In this embodiment, the circumferential length of the main body sheet 12 is set to a dimension that allows it to be wrapped around the hammer case 3 by approximately one and a half revolutions. Excavated soil that is blown forcefully upward along the outer surface of the hammer case 3 from the gap between the hole being excavated and the hammer case 3 is received by the underside of the umbrella-shaped main body sheet 12 that is wrapped around the hammer case 3, falls downward, and is deposited around the hole being excavated.

[0025] The holding means 13 is composed of a plurality of mounting magnets 19 that are magnetically attracted to the hammer case 3. As shown in FIG. 4, the mounting magnets 19 are fixed along the arcuate edge 16 on the small diameter side of the main body sheet 12, and eight mounting magnets 19 are fixed at equal intervals to the arcuate edge 16 on the small diameter side. By magnetically attracting each mounting magnet 19 to the hammer case 3, the excavated soil scattering prevention device 1 can be attached to the hammer case 3 (see FIG. 1). Each mounting magnet 19 can be fixed to the main body sheet 12 with a fastener such as a screw. In addition, to strengthen the holding force of the mounting magnets 19, it is preferable that the mounting magnets 19 be made of neodymium magnets.

[0026] The main body sheet 12 is wound around the hammer case 3 one or more times, so that the ends of the main body sheet 12 wound around the hammer case 3 overlap one another, as shown in FIG. 3 . If the overlapping portions 22 were not connected, gaps would form in the overlapping portions 22, potentially allowing excavated soil to slip through the gaps and scatter upward. To resolve this issue, this embodiment provides connecting means 23 for connecting the overlapping portions 22 of the main body sheet 12. The left and right ends of the main body sheet 12 are overlapped in the overlapping portions 22 so that they overlap. As shown in FIGS. 1 and 3 , when the excavated soil scattering prevention device 1 is attached to the hammer case 3, the mounting magnets 19 in the overlapping portions 22 are magnetically attracted to the hammer case 3 via the main body sheet 12, and the other mounting magnets 19 are magnetically attracted directly to the hammer case 3.

[0027] 4, the connecting means 23 is composed of an upper attraction plate (attraction body) 24, a lower connecting magnet (connecting magnet) 25 magnetically attracted to the upper attraction plate 24, a lower attraction plate 26, and an upper connecting magnet 27 magnetically attracted to the lower attraction plate 26. The upper attraction plate 24 is disposed on the upper surface (surface 14 side) of the main body sheet 12 located on the lower side in the overlapping portion 22, and the lower connecting magnet 25 is disposed on the lower surface (lining 15 side) of the main body sheet 12 located on the upper side in the overlapping portion 22. The lower attraction plate 26 is disposed on the lower surface (lining 15 side) of the main body sheet 12 located on the upper side in the overlapping portion 22, and the upper connecting magnet 27 is disposed on the upper surface (outer body 14 side) of the main body sheet 12 located on the lower side in the overlapping portion 22.

[0028] More specifically, when the main body sheet 12 is unfolded in a plane, the upper suction plates 24 are provided at the large-diameter arcuate edge 17 on the right half of the main body sheet 12 and at approximately the midpoint between the arcuate edge portions 16 and 17, with three upper suction plates 24 arranged at each position in the circumferential direction of the main body sheet 12. The lower connecting magnets 25 are arranged at approximately the midpoint of the linear edge portion 18 on the left end side of the main body sheet 12 and near the large-diameter arcuate edge portion 17. In the overlapping portion 22 of the main body sheet 12, the lower connecting magnets 25 are magnetically attracted to the upper suction plates 24, thereby connecting the left end of the main body sheet 12 to the upper surface of the right half of the main body sheet 12.

[0029] Furthermore, when the main body sheet 12 is laid out flat, the lower suction plate 26 is provided on the large-diameter arcuate edge 17 of the left half of the main body sheet 12, and three lower suction plates 26 are arranged circumferentially around the arcuate edge 17 of the main body sheet 12. The upper connecting magnet 27 is arranged near the large-diameter arcuate edge 17 of the straight edge 18 on the right end of the main body sheet 12. The upper connecting magnet 27 is magnetically attracted to the lower suction plate 26 at the overlapping portion 22 of the main body sheet 12, thereby connecting the right end of the main body sheet 12 to the underside of the left half of the main body sheet 12. The lower connecting magnet 25 and the upper connecting magnet 27 are fixed to the main body sheet 12 in the same manner as the mounting magnet 19, and it is preferable to use neodymium magnets to strengthen the holding force. The upper suction plate 24 and the lower suction plate 26 can be fixed to the main body sheet 12 with rivets or the like.

[0030] The excavated soil scattering prevention device 1 is configured such that the main body sheet 12 is wrapped around the hammer case 3, so one type of main body sheet 12 can be attached to multiple down-the-hole hammers 2 having hammer cases 3 with different diameters. The circumferential length of the overlapping portion 22 of the main body sheet 12 wrapped around the hammer case 3 varies depending on the diameter of the hammer case 3. As the diameter of the hammer case 3 increases, the circumferential length of the overlapping portion 22 of the main body sheet 12 decreases. Conversely, as the diameter of the hammer case 3 decreases, the circumferential length of the overlapping portion 22 of the main body sheet 12 increases. For this reason, multiple upper and lower suction plates 24 and 26 are provided in the circumferential direction. Three or more of each of the suction plates 24 and 26 may be provided.

[0031] Because the main body sheet 12 is formed from a flexible sheet body, there is a risk that the main body sheet 12 alone will not be able to maintain the umbrella-like shape that spreads downward when wound around the hammer case 3. Therefore, in order to maintain the umbrella shape of the main body sheet 12 wound around the hammer case 3, a shape-retaining means 30 for maintaining the umbrella shape is provided on the main body sheet 12. The shape-retaining means 30 is made of a flexible metal wire rope 31.

[0032] The wire rope 31 is arranged concentrically along the partial annular shape of the main sheet 12 at the arc edge 17 on the larger diameter side of the main sheet 12 and at a position approximately midway between the arc edge portions 16 and 17, and is fixed to the main sheet 12 by sewing the outer fabric 14 and the lining fabric 15 together on the inside and outside of the wire rope 31 (see Figure 6). When the excavated soil scattering prevention device 1 is attached to the hammer case 3, the wire rope 31 is flexed and deformed so that its radius of curvature is larger than that of the wire rope 31 when the main sheet 12 is unfolded flat, and the elastic restoring force of the wire rope 31 unfolds the main sheet 12, allowing the main sheet 12 to maintain its umbrella-like shape spreading downward.

[0033] In Figure 4, reference numeral 32 denotes handles used when handling the excavated soil scattering prevention device 1, and one handle 32 is provided on each of the left and right halves of the main body sheet 12. Using the handles 32 makes it easy to attach, detach, or transport the excavated soil scattering prevention device 1. Here, an example of how to attach the excavated soil scattering prevention device 1 will be described. First, the excavated soil scattering prevention device 1 with the main body sheet 12 unfolded is lifted from the rear side in Figure 4 using the handles 32, 32, and the attachment magnet 19 located in the circumferential center of the main body sheet 12 is attracted to the hammer case 3. Next, the right half of the main body sheet 12 is placed so that the arc edge portion 16 on the small diameter side is in contact with the outer peripheral surface of the hammer case 3, while the mounting magnets 19 are successively attracted to the hammer case 3, and then the left half of the main body sheet 12 is placed over the right half of the main body sheet 12, while the arc edge portion 16 on the small diameter side is in contact with the outer peripheral surface of the hammer case 3, while the mounting magnets 19 are successively attracted to the hammer case 3. This completes the attachment of the excavated soil scattering prevention device 1 to the down-the-hole hammer 2 (hammer case 3).

[0034] When separating the excavated soil scattering prevention device 1 from the excavated soil scattering prevention device 1, the end of the main body sheet 12 covering the upper side of the overlapping portion 22 can be grasped and pulled, and the main body sheet 12 can be peeled off from the hammer case 3. The separated excavated soil scattering prevention device 1 can be rolled up into a cone shape by rolling the main body sheet 12 along the annular shape from either end, thereby making it compact.

[0035] The excavated soil scattering prevention device 1 can be attached to the down-the-hole hammer 2 at any height, so when excavation work begins, the excavated soil scattering prevention device 1 is attached at a height of about 80 cm from the ground. This makes it possible to visually check the excavation position when excavation work begins, and excavation can be started while confirming that the bit 5 is positioned in the correct position. However, with conventional excavated soil scattering prevention devices that are installed on the ground, it is difficult to visually check the excavation position. As excavation work progresses and the excavated soil scattering prevention device 1 approaches the ground, the operation of the down-the-hole hammer 2 can be temporarily stopped and the excavated soil scattering prevention device 1 can be reattached at a position away from the ground, allowing further excavation work to be continued.

[0036] As described above, in the excavated soil scattering prevention device 1 of this embodiment, the main sheet 12, which is a flexible sheet formed into a partially annular shape, is wound around the outer peripheral surface of the hammer case 3 in an umbrella-like shape that spreads downward, making one and a half turns. This allows the main sheet 12 to catch the excavated soil blown upward along the outer surface of the down-the-hole hammer 2 along with the operating air, preventing the excavated soil from scattering around. Furthermore, the excavated soil scattering prevention device 1 can be attached to the down-the-hole hammer 2 simply by wrapping the partially annular main sheet 12 around the hammer case 3 and holding it in place relative to the hammer case 3 with the retaining means 13. It can be separated from the down-the-hole hammer 2 simply by releasing the retaining means 13. This eliminates the need for adjusting the adjustment ribs, which was previously required, and simplifies the installation (mounting) and removal (separation) of the excavated soil scattering prevention device 1. Furthermore, by rolling the main sheet 12 into a conical shape, the volume of the excavated soil scattering prevention device 1 can be made more compact when not in use. As described above, the excavated soil scattering prevention device of this embodiment not only prevents excavated soil from scattering and reduces the time required for curing work, but also significantly reduces the time required for preparation work when excavating because the excavated soil scattering prevention device 1 can be easily attached and detached to the down-the-hole hammer 2. Furthermore, since the volume can be made compact when not in use, it can be stored and transported without taking up too much space.

[0037] The holding means 13 is configured with a plurality of mounting magnets 19 fixed along the arc edge 16 on the small diameter side of the main body sheet 12 and magnetically attracted to the hammer case 3, so that the device 1 to prevent excavated soil from scattering can be attached to the down-the-hole hammer 2 simply by winding the main body sheet 12 while the mounting magnets 19 are attracted to the hammer case 3 so that the arc edge 16 on the small diameter side of the main body sheet 12 comes into contact with the hammer case 3. In addition, the device 1 to prevent excavated soil from scattering can be separated from the down-the-hole hammer 2 simply by pulling the main body sheet 12 so as to peel the mounting magnets 19 off the hammer case 3.

[0038] The main body sheet 12 is provided with connecting means 23 that connects the overlapping portions 22 of the main body sheet 12 wrapped around the hammer case 3, thereby integrating the ends of the main body sheet 12 and eliminating gaps in the overlapping portions 22. This prevents excavated soil from scattering through the gaps, resulting in a more reliable excavated soil scattering prevention device. The connecting means 23 is composed of an upper suction plate 24, a lower connecting magnet 25, a lower suction plate 26, and an upper connecting magnet 27, which are arranged in the overlapping portions 22 of the main body sheet 12. This allows the overlapping portions 22 of the main body sheet 12 to be connected and integrated by the simple operation of simply attaching the connecting magnets 25, 27 to the suction plates 24, 26.

[0039] The main body sheet 12 is provided with a shape-retaining means 30 that maintains the shape of the main body sheet 12, which is wrapped around the hammer case 3 in an umbrella shape. This reduces deformation of the main body sheet 12 when excavated soil is received, allowing the excavated soil to be accurately received and prevented from scattering. Furthermore, the shape-retaining means 30 is configured with a flexible metal wire rope 31 fixed along the annular shape of the main body sheet 12. This allows the main body sheet 12 to be stretched by utilizing the elastic restoring force of the wire rope 31, thereby maintaining the umbrella shape of the main body sheet 12 with a simple configuration. Furthermore, the wire rope 31 bends and stretches in response to changes in the shape of the main body sheet 12, allowing it to be freely adapted to the shape of the main body sheet 12, such as when the main body sheet 12 is unfolded flat, when the main body sheet 12 is wrapped around the hammer case 3, or when the main body sheet 12 is rolled into a cone shape.

[0040] In addition to the above, the holding means 13 can be configured with a hook and an elastic band arranged circumferentially around the hammer case 3 and engaged with the hook, and the contraction force of the band can be used to tighten the hammer case 3 at the arc edge portion 16 on the small diameter side, thereby holding the main body sheet 12 in place. The connecting means 23 can be configured with a hook or a hook-and-loop fastener. The shape-retaining means 30 can be configured with a flexible resin rod. [Explanation of symbols]

[0041] 1. Equipment to prevent excavated soil from scattering 2 Down-the-hole hammer 3 Hammer Case 12 Main sheet 13 Stopper (retaining means) 16 Arc edge on the small diameter side 19 Mounting magnet 22 Overlapping part 23 Connection means 24 Adsorption body (upper adsorption plate) 25 Connecting magnet (lower connecting magnet) 30 Shape preservation means 31 Wire rope

Claims

1. A device for preventing excavated soil from scattering is attached to a down-the-hole hammer (2) including a hollow cylindrical hammer case (3) and catches excavated soil blown upward along the outer surface of the hammer case (3), a main body sheet (12) formed of a flexible sheet body in a partially annular shape and attached to the hammer case (3) in an umbrella-like position that spreads downward, with a circular edge (16) on the small diameter side in contact with the outer peripheral surface of the hammer case (3); a stopper (13) for holding the main body sheet (12) attached to the hammer case (3) in position; A device for preventing excavated soil from scattering, characterized by comprising:

2. 2. A device for preventing excavated soil from scattering as described in claim 1, wherein the stopper (13) is fixed along the arc edge (16) on the small diameter side of the main body sheet (12) and is composed of a plurality of attached magnets (19) that are magnetically attracted to the hammer case (3).

3. A device for preventing excavated soil from scattering as described in claim 1 or 2, wherein the main body sheet (12) is provided with a connecting means (23) for connecting the overlapping portion (22) of the main body sheet (12) when attached to the hammer case (3).

4. 4. The excavated soil scattering prevention device according to claim 3, wherein the connecting means (23) includes an adsorbent (24) arranged on the upper surface of the main body sheet (12) located on the lower side in the overlapping portion (22) of the main body sheet (12), and a connecting magnet (25) arranged on the lower surface of the main body sheet (12) located on the upper side in the overlapping portion (22) of the main body sheet (12) and magnetically attracted to the adsorbent (24).

5. 3. A device for preventing excavated soil from scattering as described in claim 1 or 2, wherein the main body sheet (12) is provided with a shape-retaining means (30) for maintaining the shape of the main body sheet (12) which is wrapped around the hammer case (3) in an umbrella-like shape.

6. 6. A device for preventing excavated soil from scattering as described in claim 5, wherein the shape-retaining means (30) is composed of a flexible metal wire rope (31) fixed along the partially annular shape of the main body sheet (12).

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