JP2011032775A - Drilling method for vertical hole, and spattering preventive cover for hammer grab - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spattering preventive cover capable of preventing water and mud from being spattered toward a periphery, even when a drilled object is dropped into a casing in drilling of a vertical hole, or even when a hammer grab is pulled up to convey the drilled object laterally. <P>SOLUTION: This spattering preventive cover (1) for covering an opening part of the casing (C) is constituted of a steel top plate (2) and skirt part (3), and a foldable flexible sheet (12) rolled on an outer circumferential part of the skirt part (3). A hole (4) is drilled to penetrate a suspending wire (25) of the hammer grab (20) therethrough, in the central part of the top plate (2). Slits (10) inserted with the wire (25) are provided in the top plate (2) and skirt part (3). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a vertical hole excavation method and a hammer grab scattering prevention cover, and more particularly to an excavation method using a hammer grab and a scattering prevention cover used together with the hammer grab.

  The all-casing method is known as one of the underground excavation method or earth removal method. This method consists of rotating a steel pipe, i.e., a casing, provided with a plurality of excavation claws at the lower end, cutting the ground with the claws and inserting it into the ground, excavating the earth and sand in the inserted casing with an excavator, It is a method of excavating and excavating vertical holes. Pile is constructed by placing concrete in this vertical hole. Hammer grabs are used for drilling such vertical holes. The hammer grab includes a cylindrical grab body as is well known in the art. An opening / closing mechanism comprising a plurality of sheaves is provided inside the main body, and a plurality of shells are provided at the lower end thereof. The grab body configured as described above is detachably held by a support fitting, that is, a crown. The crown is suspended by a plurality of suspension ropes, for example, by a crane. The crane is also provided with an operation wire rope. By operating this wire rope, the opening and closing mechanism is driven to open and close a plurality of shells, and the grab body is pulled up to the crown so that it can be attached and detached.

  Since the hammer grab is generally configured as described above, a vertical hole can be drilled using the hammer grab as follows. That is, the grab body is suspended by a crane at a predetermined position in the casing inserted into the soil, and the operation wire rope is loosened. Then, an opening / closing mechanism composed of a plurality of sheaves operates to open the shell. It is also cut off from the crown. The grab body falls by gravity with the shell down, and the shell bites into the soil from its tip. Therefore, the operation wire rope is wound up. By this operation, the opening / closing mechanism is actuated to close the shell. Since it closes, excavated objects such as mud, sand, and obstacles located inside the plurality of shells are gripped by being sandwiched by the plurality of shells. When the operation wire rope is further wound up, the grab main body is connected to the crown while grasping the discharged object. Thereafter, the grab main body is suspended by a suspension rope that suspends the crown, and is moved, for example, to a place where a portion to be excavated is deposited. Loosen the operating wire rope. Then, the opening / closing mechanism is activated to open the shell, and the work to be excavated is discharged. A vertical hole can be excavated by repeating the above operation.

  Various problems arise when excavating as described above. For example, mud, earth and sand caught by the shell during the period from when the excavated object is lifted above the casing to when the excavated part is temporarily deposited, that is, when it is moved to the soil removal position There is a problem that an object to be excavated such as an object and muddy water leaks from the shell and is scattered and hits the environment. Therefore, Patent Document 1 proposes a hammer grab cover device that solves such a scattering problem.

JP 2001-323768 A

  The cover device described in Patent Literature 1 wraps a hammer grab body suspended on the ground, and is composed of upper and lower rings having a diameter larger than that of the hammer grab body and a resin sheet. The upper and lower ends of the resin sheet are respectively attached to the upper and lower rings. Therefore, when the cover apparatus is installed on the ground and excavated by the hammer grab as described above to lift the grab main body to the ground, the grab main body is accommodated in the cover apparatus together with the work to be excavated by the shell. Therefore, the grab body is moved to the soil removal position. Since the grab body is housed in the cover device, a part of the excavated material leaks from the shell and is prevented by the resin sheet even if it tries to fly around. This prevents environmental pollution near the construction site.

  The proposed hammer grab cover device wraps the grab body suspended on the ground, so there is a problem when moving the grab body holding the object to be excavated to the earthing position, that is, on the ground. The problem is solved. However, the problems that occur in the casing are not solved. More specifically, the work to be excavated by the shell may fall from the shell when it is pulled up. In particular, if the object to be excavated is larger than the shell, the object to be excavated is held in an unstable state with respect to the shell. The excavated object may fall from the shell due to vibration or the like when the main body or the shell contacts the casing. When dropped, the casing presents a cylindrical sealed space, so the inside of the casing is temporarily compressed by the fallen object, and groundwater, mud, etc. accumulated in the casing by the compressed air is vigorously removed from the casing. Blows outside and scatters around. When a large lump that is substantially in contact with the inner peripheral surface of the casing falls, the effect of air compression increases, so the blowing force is large and the blowing height is, for example, 20 to 30 m. The impact on the environment is even greater. There may be a disaster to the human body due to the blown up objects, and particularly when the all casing method is carried out in an urban area, the surrounding environment is affected.

  Since the hammer grab cover device proposed in Patent Document 1 is also arranged above the casing, it seems that scattering due to blowing up can be prevented. However, the cover device includes a pair of rings and Since the resin sheet attached to these rings is formed in a substantially cylindrical shape and the upper part is open, the blown up matter scatters through the opening. Even if the upper opening is closed, the cover device described in Patent Document 1 is composed of a pair of upper and lower rings and a resin sheet, that is, even if the pair of rings is made of iron having a large specific gravity. Since the ring has a lightweight structure, it is lightweight as a whole, and the blowing force cannot be suppressed by the weight of the cover device. Moreover, even if a weak blow-up can be prevented, it is considered that the proposed cover device is not easy to arrange above the casing in terms of structure. In other words, the cover device generally interferes with excavation work using a hammer grab, but it does not seem easy to remove and install. Furthermore, it is expected that it is difficult to align the cover device with the casing.

  An object of the present invention is to provide a vertical hole excavation method using a hammer grab and a hammer grab scattering prevention cover, which solve the above-described conventional problems. More specifically, the problem when holding the excavated object with a plurality of shells and lifting the hammer grab body in the casing is also raised to the earth removal position where the excavated part is temporarily accumulated by lifting it to the ground. It is an object of the present invention to provide a method for excavating a vertical hole using a hammer grab and a cover for preventing the hammer grab from scattering, which also solves the problem when moving.

  In order to achieve the above object, in the so-called all-casing method, the present invention inserts a hammer grab suspended by a wire into a casing driven into the ground, and cuts the work to be cut in the casing. When sandwiching and pulling up, the opening of the casing is configured to be covered with a scattering prevention cover. Specifically, the scattering prevention cover is integrally connected to a top plate portion made of a steel plate having a substantially reverse funnel shape having a larger diameter than an opening portion of the casing and a lower end portion of an outer peripheral portion of the top plate portion. It consists of a steel plate skirt. A hole having a predetermined size is formed in the center portion of the top plate portion, and a slit reaching the hole is provided in the top plate portion and the skirt portion. In addition, a foldable flexible sheet that can be extended downward is provided on the outer peripheral portion of the skirt portion. Such a scattering prevention cover is placed on the opening of the casing before the hammer grab suspended by a wire in the casing is pulled up. That is, the opening is covered. At this time, the wire is passed through the hole of the anti-scatter cover through the slit. Further, the flexible sheet is extended downward. Then, the work to be excavated is sandwiched and lifted by the hammer grab. When the hammer grab and work piece are pulled up from the casing, they are covered with a flexible skirt.

Thus, according to the first aspect of the present invention, a cylindrical casing is driven into the ground in the vertical direction, a hammer grab suspended by a wire is inserted into the casing, and the cut excavation in the casing is performed. In the construction method of sandwiching a work with the hammer grab, pulling up the hammer grab in the sandwiched state, and moving to a predetermined location to discharge the work to be excavated and excavating a vertical hole, the step of lifting the hammer grab The opening of the casing is configured to be covered with a steel plate anti-scattering cover provided with a hole of a predetermined size for allowing the wire to pass therethrough.
According to a second aspect of the present invention, a cylindrical casing is driven in a vertical direction on the ground, a hammer grab suspended by a wire is inserted into the casing, and the cut excavation in the casing is performed. In the construction method of sandwiching a work with the hammer grab, pulling up the hammer grab in the sandwiched state, and moving to a predetermined location to discharge the work to be excavated and excavating a vertical hole, the step of lifting the hammer grab The step of moving the hammer grab in a state where the opening of the casing is covered with a steel plate anti-scattering cover provided with a hole of a predetermined size through which the wire passes, and the hammer grab and the excavated cut It is configured to carry out in a state where the object is covered with the steel plate scattering prevention cover and a flexible sheet provided on the outer periphery of the scattering prevention cover It is.

According to a third aspect of the present invention, a cylindrical casing is driven vertically into the ground, a hammer grab suspended by a wire is inserted into the casing, and the cut excavated work in the casing is inserted. Is a scattering prevention cover that is used when excavating a vertical hole by excavating the work to be excavated by pulling up the hammer grab in the sandwiched state, lifting the hammer grab and moving it to a predetermined location, The anti-scatter cover is made of a steel plate that is integrally connected to a bottom plate portion of a steel plate having a substantially reverse funnel shape having a larger diameter than the opening of the casing and an outer peripheral portion of the top plate portion. A skirt portion is formed, and a hole of a predetermined size is formed in a central portion of the top plate portion, and the hammer grab is inserted into the casing by passing the wire through the hole. In state, the scattering prevention cover is configured to be able to place the opening of the casing.
According to a fourth aspect of the present invention, in the anti-scattering cover according to the third aspect, the top plate portion and the skirt portion are provided with slits reaching the holes of the top plate portion, and the wire Is configured to be able to pass through the hole through the slit.
According to a fifth aspect of the present invention, in the scattering prevention cover according to the fourth aspect, the top plate portion and the skirt portion are provided with an opening / closing member that opens and closes the slit.
Furthermore, the invention according to claim 6 is the foldable flexible sheet that can be extended downward on the outer peripheral portion of the skirt portion in the scattering prevention cover according to any one of claims 3 to 5. Is configured to be provided.

  As described above, according to the present invention, in the so-called all-casing method of excavating a vertical hole, the step of pulling up the hammer grab inserted into the casing has a predetermined size through which the casing hanging wire is passed. Since it is configured to be carried out in a state covered with a steel plate anti-scattering cover provided with a hole, the work to be excavated sandwiched by the hammer grab falls in the casing and falls into the casing. Even if the accumulated groundwater or mud is blown up, the scattering prevention cover can surely prevent the scattering and the environment is not polluted. According to still another invention, the step of moving the hammer grab carried out after lifting the hammer grab is provided with the hammer grab and the work to be cut on the outer periphery of the steel plate anti-scattering cover and the anti-scattering cover. Since it is configured so as to be covered with a flexible sheet, water and mud do not scatter from the hammer grab and the work to be excavated on the ground. Therefore, a good environment is maintained. According to another invention, the anti-scattering cover is integrally formed with a steel plate top plate having a substantially reverse funnel shape having a larger diameter than the opening of the casing, and a lower end portion of the outer peripheral portion of the top plate portion. It is composed of a connected steel skirt and a simple structure with a hole of a predetermined size in the center of the top plate. Can be provided to. According to the invention, the top plate portion and the skirt portion have slits reaching the holes in the top plate portion, and the wire can be passed through the holes through the slits. Thus, when covering the opening of the casing, the wire hanging the hammer grab is not obstructed, and the wire can be easily passed through the hole of the anti-scatter cover. Furthermore, according to the invention in which a foldable flexible sheet that can be extended downward is provided on the outer periphery of the skirt, the flexible sheet is inexpensive and has a simple configuration, An effect is obtained that it is possible to reliably prevent the mud from scattering.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows typically the scattering prevention cover and hammer grab which concern on embodiment of this invention, The (a) is a front view which shows a scattering prevention cover in a partial cross section, The (a) is a hammer grab FIG. It is a front view which shows typically the scattering prevention cover and hammer grab in each step of the vertical hole excavation process which concerns on the form of this invention.

  First, the scattering prevention cover according to the embodiment of the present invention will be described. As shown in FIG. 1A, the scattering prevention cover 1 is schematically composed of a top plate portion 2, a skirt portion 3, and a through portion 4. The top plate 2 has a diameter that tapers from the upper end toward the lower end. In other words, the funnel is turned upside down. The lower end portion of the top plate portion 2 has a maximum diameter, and the diameter of the lower end portion is selected to be sufficiently larger than the diameter of the casing to which it is applied. From such a lower end portion of the top plate portion 2, the skirt portion 3 extends downward by a predetermined length, and the through portion 4 rises from the upper end portion of the top plate portion 2 by a predetermined height. The diameter of the penetrating portion 4 is selected so that a part of the hammer grab to be applied passes but the ring-shaped support member attached to the hammer grab cannot pass as will be described later.

  According to the present embodiment, the top plate portion 2 has a double structure having substantially the same shape, and the top plate located inside serves as a guide portion 2a that guides when the hammer grab is lifted. According to the present embodiment, since the guide portion 2a is provided, even when the suspension wire is lifted, the suspension wire is shaken and even if the axis of the hammer grab is slightly displaced, the guide portion 2a is smoothly guided. Furthermore, according to the present embodiment, a part of the skirt portion 3 also has a double structure. That is, it consists of a long skirt portion 3 located on the outside and a short auxiliary skirt portion 3a located on the inside. The upper end portions of these skirt portions 3 and 3a are held at a predetermined interval S by a disk-shaped spacer 5. During this interval S, a casing, which will be described later, enters and the spacer 5 is placed on the upper edge.

  The hammer grab is generally suspended by a suspension wire, and the shell is opened and closed by an operation wire. Therefore, the hammer grab is suspended by these wires and inserted into the casing so that the splash prevention cover can be used. 1, that is, a slit 10 through which these wires pass is formed in the anti-scattering cover 1. As shown in FIG. 1A, the slit 10 is formed over the guide portion 2a and the spacer 5 though not shown in the through portion 4, the top plate portion 2, the skirt portion 3, and FIG. . As a result, when the wires 4b and 4b are hung on the hooks 4a and 4a of the penetrating part 4 and the slit 10 is moved in the lateral direction so as to be positioned on the wire and the operation wire hanging the hammer grab. The anti-scattering cover 1 can be attached and removed. Since the top plate portion 2 and the skirt portion 3 are provided with doors 6a, 6b having a rectangular shape in the vicinity of the slit 10 so as to be rotatable by a predetermined hinge, the door 6a, The slit 10 can be closed by 6b.

  The scattering prevention cover 1, that is, the top plate portion 2, the skirt portion 3, and the penetrating portion 4 configured as described above, preferably the guide portion 2a, the auxiliary skirt 3a, the spacer 5, and the doors 6a and 6b are also present in the present embodiment. According to the present invention, it is composed of a steel plate so as to have a predetermined weight and strength. Thereby, the above-mentioned blowing-up can be suppressed by the weight of the anti-scattering cover 1.

  A flexible skirt portion sheet 12 is provided on the outer peripheral portion of the skirt portion 3. That is, the skirt portion 20 is provided with a plurality of hook-shaped hooks 12a, 12a,... At predetermined intervals in the circumferential direction, and the skirt sheet 12 is detachable from the hooks 12a, 12a,. Is attached. .. Are connected to the hooks 12a, 12a,..., And hooks 12c, 12c,... Are provided at the ends of the rubber strings 12b, 12b,. In a folded state, the skirt portion sheet 12 is pressed by the rubber strings 12 b, 12 b,..., And the hooks 12 c, 12 c at the tip are hooked on the lower end portion of the skirt portion 3. Therefore, when the hooks 12c, 12c,... Are removed, the folded skirt sheet 12 is released from the rubber straps 12b, 12b,... And spreads as shown by a chain line 12d in FIG. It hangs down below the skirt part 3 and wraps around the hammer grab. It is also possible to squeeze the hanging end with a rope or the like.

  The same flexible penetration part sheet | seat 13 is similarly similarly provided in the outer peripheral part of the penetration part 4 so that attachment or detachment is possible. When pulling up the hammer grab, the main body of the grab comes to be located directly under the penetration part 4, so the blow-up is blocked by the grab body, and the amount of blow-up through the penetration part 4 is small, so this sheet can be used as needed Is done.

  As the hammer grab, a mechanical grab and a hydraulic grab are well known in the art. Since such a known grab can be applied, the mechanical hammer grab 20 will be briefly described below with reference to FIG. The hammer grab 20 includes a grab main body 21 formed in a frame shape from a plurality of rod-shaped members. An opening / closing mechanism 22 including a plurality of sheaves, pulleys, and the like is provided inside the main body 21, and two shells 23, 23 that are pin-coupled are provided at the lower end of the opening / closing mechanism 22. The grab body 21 configured as described above is suspended by a suspension chain 25, and the suspension chain 25 is fixed to a bracket 26. The operation wire 27 for operating the hammer grab 20 passes through the through hole of the bracket 26, is hung around a pulley or the like constituting the opening / closing mechanism 22, and its end portion is fixed to the frame. Therefore, when the operation wire 27 is wound up, it acts on the opening / closing mechanism 22, the shells 23 and 23 are closed, and the work to be excavated is grasped. When the hanging chain 25 is wound up, the grab body 21 is carried out of the casing in a state where the work to be excavated is held by the shells 23 and 23. When the operation wire 27 is loosened while the grab body 21 is suspended by another wire, the pair of shells 23 and 23 are opened, and the object to be excavated is discharged.

  A ring-shaped support member 28 is provided on the main body 21 of the hammer grab 20 thus configured. The outer diameter of the support member 28 is smaller than the outer diameter of the grab main body 21 described above, but is sufficiently smaller than the inner diameter of the penetrating portion 4 of the anti-scattering cover 1. 4, and supports the grab main body 21.

  Next, the operation of the above embodiment will be described mainly with reference to FIG. As shown in FIG. 2A, the steel pipe, that is, the casing C is pushed into the soil while being rotated as conventionally known. If it does so, the hard rock in the ground will also be cut by the nail | claw provided in the front-end | tip of the casing C, ie, the cutter bit C1. When a huge boulder or a remnant of the foundation of a building is buried in the ground, these are cut and a massive excavated object H is formed. In this way, when the casing C is pushed into the soil, the portion C 'that is exposed on the ground surface is left at a predetermined height or more. This is because the scattering prevention cover 1 is placed on the portion C ′ protruding on the ground surface, and the protruding portion C ′ also serves as a member for positioning and supporting the scattering prevention cover 1. The hammer grab 20 is lowered into the casing C with the pair of shells 23 and 23 being opened. When earth and sand or a relatively soft ground is exposed at the bottom of the casing C, the shells 23 and 23 pierce them. However, if the excavated material K cut by the casing C is composed of hard rock, rocks, remains of the foundation of the building, etc. and is relatively large, the shells 23 and 23 are formed between the excavated material K and the casing C. It is inserted into the gap. Such a state is shown in FIG.

  When the operation wire 27 is wound up and the excavated object K is soft, as described above, the shells 23 and 23 of the grab main body 21 are completely closed, and the excavated object is sandwiched between the pair of shells 23 and 23, and substantially. Can be crawled up. However, when the work K is hard and large, the shells 23 and 23 are not completely closed. Accordingly, the side of the excavated object K is only sandwiched between the shells 23 and 23. Then, when the grab main body 21 is pulled up, the excavated object K is only pinched by the frictional force, so it may fall in the casing C, and groundwater, mud, etc. accumulated in the casing C can be blown up. There is sex. Therefore, the scattering prevention cover 1 according to the present embodiment is set in the casing C before the grab body 21 is pulled up. Specifically, the scattering prevention cover 1 is placed on a portion C ′ of the casing C on the ground surface. That is, the scattering prevention cover 1 is suspended by the suspension wires 4b and 4b, and is moved laterally so that the slit 10 is aligned with the suspension chain 25 of the hammer grab 20, and the axis of the scattering prevention cover 1 is moved to the grab body 21. It is made to correspond to the axis, that is, the axis of the hanging chain 25. Then, the suspension wires 4b and 4b are loosened, and the scattering prevention cover 1 is lowered onto the casing C. The spacer 5 of the anti-scattering cover 1 is placed on the upper end of the portion C ′ protruding from the ground surface. This state is shown in FIG. Until it is placed, the skirt sheet 12 and the penetration sheet 13 are both rolled up, and the doors 6a and 6b of the slit 10 are opened. In FIG. 2A, the slit 10, the doors 6a and 6b, etc. are not shown.

  Wind up the suspension chain 25. The stage in the middle of winding is shown in FIG. When winding is started or before starting, the skirt sheet 12 is lowered, the penetrating sheet 13 is raised, and the doors 6a and 6b of the slit 10 are closed.

  Continue winding. Then, a part of the upper part of the hammer grab 20 penetrates the penetration part 4 of the scattering prevention cover 1, but the support member 28 attached to the grab main body 21 comes into contact with the penetration part 4 of the scattering prevention cover 1. Such a state is shown in FIG. When the support member 28 is in contact with the penetrating part 4, the penetrating part 4 is substantially closed, so that the penetrating part 4 can be used even if the excavated material K falls in the casing C and groundwater, mud, etc. are blown up. Will not erupt from. The penetration part sheet | seat 13 is removed as needed. Thereafter, the scattering prevention cover 1 is pulled up together with the hammer grab 20. A state in which the casing C is pulled up from the casing C and moved in the horizontal direction is shown in FIG. In this state, the hammer grab 20 is moved to the soil removal position. Then, although not shown in the drawing, the frame member of the hammer grab 20 is suspended by another suspension device, and the suspension chain 25 is loosened. Alternatively, the operation wire 27 is loosened. Then, as described above, the pair of shells 23 and 23 are opened, and the drilled object H is discharged.

  While the scattering prevention cover 1 is suspended from the hammer grab 20, the skirt portion sheet 12 is folded and the hammer grab 20 is lowered into the casing C. Then, the spacer 5 of the scattering prevention cover 1 comes into contact with the upper end portion of the casing C and is held. Thereafter, the operation is repeated in the same manner.

  According to the present embodiment, the anti-scattering cover 1 made of metal, that is, a steel plate, is put on the upper end portion of the casing C, and the hammaglab 1 is pulled up. Therefore, the excavated object H falls from the shell, and groundwater, mud, etc. in the casing Even if it tries to blow up vigorously, it is prevented by the scattering prevention cover 1. Even if the blowing force is strong, the steel plate scattering prevention cover 1 is heavy, so that scattering is prevented. Further, when the glove body 21 is pulled up to the ground, the shells 23 and 23 that hold the grab main body 21 with the digging object H are also encased by the skirt portion 3 and the skirt portion sheet 12, so that environmental pollution is caused when transporting to the soil removal position. Is also prevented.

  The present invention is not limited to the above embodiment and can be implemented in various forms. For example, since the guide part 2a is provided in the ceiling part 2, it is guided when the hammer grab 20 is pulled up by the guide part 2a. However, the guide part 2a can be implemented without the guide part 2a. Moreover, since the width | variety of the slit 10 is generally narrow, since it is thought that the quantity of muddy water etc. to blow up is also small, there is no need of a door. When there is no door, it may be placed so that the slit 10 faces in the direction where the problem is small even if sludge blows out. Furthermore, according to the present embodiment, since the scattering prevention cover 1 has the skirt portion 3, the skirt portion sheet 12 is not necessarily provided. When the hammer grab 20 is rolled up, the grab main body 21 is positioned substantially directly below the penetrating portion 4, and the grab main body 21 prevents a certain amount of blow-up, so that the penetrating portion sheet 13 may be omitted. In the above-described embodiment, the support member 28 is specially provided on the hammer grab 20. However, a part of the support member 28 can be used as a support member depending on the shape of the existing frame member.

  In the present embodiment, the scattering prevention cover 1 is provided with the slit 10, and the suspension wire 25 of the hammer grab 20 is inserted through the slit 10 and passed through the through portion 4. However, the suspending wire 25 may be connected to the hammer grab 20 after passing through the penetrating portion 4 of the anti-scattering cover 1 without providing the slit 10. In this case, the anti-scattering cover 1 is always pierced by the suspension wire 25 and is transported together with the hammer grab 20, but the structure is simplified because the slit 10 is not provided.

  Furthermore, in the present embodiment, the anti-scatter cover 1 is placed on the portion C ′ of the casing C protruding from the ground, but is concentrically with the casing C and larger than the casing C. It is also possible to install a steel pipe having a different diameter and place the anti-scattering cover 1 thereon. If implemented in this way, flexibility in the amount of casing C to be driven can be obtained.

DESCRIPTION OF SYMBOLS 1 Splash prevention cover 2 Top plate part 3 Skirt part 4 Through part 6a, 6b Door 12 Skirt part sheet 13 Through part sheet 20 Hammer grab 25 Wire C Casing H Work to be cut

Claims (6)

A cylindrical casing (C) is driven into the ground in the vertical direction, and a hammer grab (20) suspended by a wire (25) is inserted into the casing (C) to cut the casing (C). The cut workpiece (H) is sandwiched between the hammer grabs (20), the hammer grab (20) is pulled up in the sandwiched state, and moved to a predetermined location to discharge the workpiece (H). In the method of drilling vertical holes,
The step of pulling up the hammer grab (20) is a steel plate scattering prevention cover (1) provided with a hole (4) of a predetermined size through which the opening of the casing (C) passes the wire (25). A vertical hole excavation method characterized by being carried out in a covered state. A cylindrical casing (C) is driven into the ground in the vertical direction, and a hammer grab (20) suspended by a wire (25) is inserted into the casing (C) to cut the casing (C). The cut workpiece (H) is sandwiched between the hammer grabs (20), the hammer grab (20) is pulled up in the sandwiched state, and moved to a predetermined location to discharge the workpiece (H). In the method of drilling vertical holes,
In the step of pulling up the hammer grab (20), the opening of the casing (C) is covered with a steel plate anti-scattering cover (1) provided with a predetermined size hole (4) through which the wire (25) is passed. Carried out in the state,
In the step of moving the hammer grab (20), the hammer grab (20) and the work to be cut (H) are provided on the outer periphery of the steel plate anti-scattering cover (1) and anti-scattering cover (1). An excavation method for a vertical hole, which is carried out in a state covered with a flexible sheet (12). A cylindrical casing (C) is driven into the ground in the vertical direction, and a hammer grab (20) suspended by a wire (25) is inserted into the casing (C) to cut the casing (C). The cut workpiece (H) is sandwiched between the hammer grabs (20), the hammer grab (20) is pulled up in the sandwiched state, and moved to a predetermined location to discharge the workpiece (H). The anti-scatter cover (1) used when drilling a vertical hole,
The anti-scatter cover (1) includes a steel plate top plate (2) having a substantially reverse funnel shape and a larger diameter than the opening of the casing (C), and an outer peripheral portion of the top plate portion (2). It is composed of a skirt (3) made of a steel plate that is integrally connected to the lower end,
A hole (4) having a predetermined size is formed in the central portion of the top plate (2). By passing the wire (25) through the hole (4), the hammer grab (20) is Spattering of hammer grabs characterized in that in the state inserted in the casing (C), the scattering prevention cover (1) can be placed in the opening of the casing (C). Prevention cover. The scattering prevention cover according to claim 3, wherein a slit (10) reaching the hole (4) of the top plate portion (2) is inserted in the top plate portion (2) and the skirt portion (3). The hammer grab scattering prevention cover is characterized in that the wire (25) can be passed through the hole (4) through the slit (10). The scattering prevention cover according to claim 4, wherein the top plate (2) and the skirt (3) are provided with opening and closing members (6a, 6b) for opening and closing the slit (10). Hammer grab splash prevention cover. The scattering prevention cover according to any one of claims 3 to 5, wherein a foldable flexible sheet (12) that can be extended downward is provided on an outer peripheral portion of the skirt portion (3). Anti-scatter cover for hammer grabs.

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