JP7473260B2 - Chuck for extracting longitudinal member and method for extracting longitudinal member - Google Patents

Description

The present invention relates to a technique for removing an existing longitudinal member from its installation location.

A longitudinal member (e.g., a pillar, pile, beam, etc.) is fixed to a support (e.g., the ground, a wall) as one of the components of a structure, or the longitudinal member is fixed to a support as a separate member from the structure and for purposes such as supporting the structure at a position above a reference surface (e.g., the ground, a wall). In the latter case, the structure is supported by the longitudinal member fixed to the support.

Here, "longitudinal members" are classified by cross-sectional structure, for example, hollow and solid, by material, for example, metal and concrete, by shape, for example, rod, shaft, pipe, and cylinder, and by function, for example, pillar, pile, beam, and reinforcing bar (reinforcing bar). In any case, "longitudinal members" may be already buried bodies, or may be prefabricated members or members constructed on-site.

The "supporting part" is, for example, soil or a wall. If the "supporting part" is soil, the "longitudinal member" is, for example, a pillar or a pile. If the "supporting part" is a wall, the "longitudinal member" is, for example, a beam.

To explain these structural materials in more detail using a parking lot as an example, examples of "longitudinal members" include power poles (an example of a "pillar") that support electrical components such as lights at a position above ground level, and one or more support columns (an example of a "pillar") that support a sign displaying fee information, etc. at a position above ground level.

The lower ends of each of these structural members are fixed to the ground (an example of a "supporting part"). A concrete foundation is buried in the ground. In this case, the lower ends of each of these structural members are buried and fixed to the concrete foundation.

There are two methods for fixing longitudinal members to the ground: driving in and embedding.

The driving method involves driving prefabricated longitudinal members (such as prefabricated piles or columns) into the ground using the striking force of a hammer, without first digging pilot holes in the soil.

In contrast, the embedding method involves excavating the ground to a specified depth to create a pilot hole, and then inserting a prefabricated longitudinal member (such as a prefabricated pile or column) into the hole. One such embedding method is known as the root wrapping method (see, for example, Patent Document 1). This root wrapping method is a method in which, for example, an enlarged concrete bulb is created at the bottom end of the longitudinal member. In this case, the enlarged bulb, i.e., the root wrapping portion or the root fixing portion, may be created using reinforcing bars or without them.

According to this method, a pilot hole is first excavated in the ground, and crushed stone is poured into the bottom of the hole and tamped down. A post is then inserted into the hole, and temporary braces are used to keep the post upright so that it does not tip over. Ready-mixed concrete is then poured into the hole so that it surrounds the post. The ready-mixed concrete is then allowed to harden, thereby fixing the post in place.

For example, as disclosed in the above-mentioned Patent Document 1, longitudinal members fixedly installed in the ground cannot remain installed in the same place semi-permanently. For example, if the installation location is rented land, the landowner may suddenly request that the longitudinal members be removed from the installation location and the installation location be returned to a vacant lot.

On the other hand, the longitudinal members may be firmly fixed to the ground (e.g., with a high pull-out strength (resistance when the longitudinal members are pulled out of the foundation, pull-out resistance)) using a concrete base. In this case, it may be necessary to expend a lot of effort (man-hours, construction time, etc.) and cost (labor costs, equipment costs, etc.) to remove the longitudinal members.

Such circumstances exist, for example, in the field of parking lot management.

Specifically, when land owned by a landowner is likely to be sold or is planned to be sold, the land becomes idle or vacant until the sale. Therefore, until the sale, the landowner may use the land to temporarily operate a parking lot, renting it out to users as a parking lot and earning rental income. In this case, the landowner may entrust the management of the parking lot to a specialized parking lot operator (or parking lot management company, etc.).

In this case, if the landowner decides to use his/her land for another purpose or to sell it, the landowner will request the parking lot operator to return his/her land to a vacant lot. In order to comply with this request, the parking lot operator will need to remove from the land the various facilities that were installed on the land for parking lot management.

At this time, it is desirable for the parking lot operator to be able to carry out the removal work with as little effort as possible, in as short a time as possible, and at the lowest possible cost.

By the way, the term "pull out" is used throughout this specification to mean, for example, the action of pulling an object within an object to which it is attached in a direction that causes the object to be removed from the object.

However, the term contains the lexical part "pull out," which means that an object is detached or separated from an object. Therefore, when using the term "pull out," it can be interpreted in a narrow sense as necessarily requiring that an object be detached from an object.

However, depending on the context, the term may be interpreted broadly to mean the action of pulling an object within an object in a direction that causes the object to move away from the object, regardless of whether the object ultimately moves away from the object.

In contrast, the term "completely pull out" is sometimes used when it is necessary to clearly distinguish the event of an object ultimately detaching from an object due to the action of pulling the object in a direction that would cause the object to detach from the object from other events.

In addition, the axial force applied to the longitudinal member in order to pull the longitudinal member out of its installation location may be defined as a force pushing the longitudinal member or a force pulling the longitudinal member. This is because whether the axial force applied to the longitudinal member is a pushing force or a pulling force, the longitudinal member will still be pulled out of the support or base.

Patent documents 1-4 disclose conventional techniques for pulling out and removing a longitudinal member from its installation location.

Patent document 1 discloses a technique for extracting a column (an example of a "longitudinal member") from the soil together with the foundation in which it is embedded.

Specifically, according to this technique, first, multiple metal tips are welded to the outer periphery of the upper end of the column, which is the part that is exposed above the foundation. Next, a wire for extraction is hooked onto the metal tips. After that, the tip of the wire is pulled up using heavy machinery such as a crane, and the column is pulled out of the ground together with the surrounding foundation.

Patent Document 2 discloses the following methods for extracting steel material (an example of a "longitudinal member") from the ground: (a) a method in which the steel material is directly extracted using a hydraulic or vibratory extractor; (b) a method in which various lubricating materials are placed around the steel material in advance as an edge separator, thereby weakening the extraction strength (resistance when the steel material is extracted), and the steel material is extracted under these conditions; and (c) a method in which a crushing agent is used.

Patent document 3 discloses a method of inserting an inclusion between the steel material (an example of a "longitudinal member") and the cement-based hardened material during the installation stage to reduce the pull-out resistance of the steel material.

Specifically, according to this technology, before the steel material is inserted into the unhardened cement-based hardened material, a resin coating that is degraded by the alkaline components in the hardened cement-based material is applied to the part of the steel material that comes into contact with the hardened cement-based material, and the resin coating is degraded by the alkaline components, making it easier to pull out the steel material.

Patent Document 4 discloses a method for removing piles (an example of a "longitudinal member") that have already been buried. Specifically, this method involves hollowing out the area around the pile together with the ground, cutting the edge between the ground and the pile, and pulling the pile out of the soil with the soil still attached.

Further, prior art techniques of chucks attached to a longitudinal member for pulling the longitudinal member from its installed position are disclosed in US Pat. Nos. 5,993,333, 5,993,614, 5,993,224 and 5,993,625.
exist.

Patent document 5 discloses a chuck that holds a stake (an example of a "longitudinal member") by clamping it between a pair of jaws on both diametric sides.

When the pair of jaws are in a holding state in which they hold the pile, they are arranged at different positions in the axial direction so that they sandwich the pile in a staggered manner in a side view. Furthermore, when in the holding state, the chuck is pulled up by a hoist together with the pile, thereby pulling the pile out of the ground, etc.

Patent document 6 discloses a chuck that grips a pillar material (an example of a "longitudinal member") by pressing three chuck jaws, which are arranged at equal angular intervals in a plan view, against the outer periphery of the pillar material (an example of a "longitudinal member") using the principle of the wedge.

Patent document 7 discloses a chuck that grips a reinforcing bar by pressing two or four divided bodies arranged at equal angular intervals in a plan view against the outer periphery of the reinforcing bar (an example of a "longitudinal member") using the principle of a wedge.

JP 2014-001542 A Japanese Patent Application Laid-Open No. 2-176014 Japanese Patent Application Laid-Open No. 59-078809 JP 2011-196114 A JP 2002-038482 A JP 2002-180466 A JP 2011-107000 A

Regardless of whether the construction method selectively implemented to fix the longitudinal member to the ground, wall or foundation is the driving method or the embedding method described above, in order to pull out such an existing longitudinal member from the ground, wall or foundation, the inventor has set the following objective.

1. Facilitates the reduction of vibrations and noise that occur during the removal of longitudinal members.

If the vibrations and noise caused by the removal of longitudinal members can be reduced, it will be possible to carry out the removal work without disturbing neighboring residents, and it will also be possible to carry out the removal work at night, when it is quieter than during the day.

2. Make it easy to remove longitudinal members using simple work and equipment.

If the work and equipment required to remove the longitudinal members could be simplified, the burden on workers would be reduced and work costs would be reduced.

3. Reduce traces of the removal process remaining on the removed longitudinal members.

If traces of the removal process remaining on the removed longitudinal members can be reduced, it will be possible to reuse the removed longitudinal members to the extent that this does not cause problems, which will result in the effective use of resources and easier reduction of equipment costs.

In light of the circumstances described above, the present invention aims to provide a technology that makes it possible to grasp an existing longitudinal member non-invasively and easily remove it from its installation location with low noise and vibration.

In order to solve the problem, according to one aspect of the present invention, there is provided a chuck that is detachably attached to a longitudinal member in order to pull out an existing longitudinal member from a support portion or a foundation portion embedded in the support portion, or to pull out the longitudinal member together with the foundation portion from the support portion,
a cylindrical contact layer that surrounds the outer peripheral surface of the longitudinal member locally in the axial direction and entirely or partially in the circumferential direction, the contact layer having elasticity at least in the radial direction and a soft material at least in a surface layer, the inner peripheral surface of the contact layer contacting the outer peripheral surface of the longitudinal member;
an outer frame that holds the contact layer in a supporting state from behind, and non-invasively grips the longitudinal member by compressing the contact layer on its inner surface against the outer circumferential surface of the longitudinal member within its elastic range;
Including,
The contact layer is a chuck for removing a longitudinal member, which is constituted by an arrangement of a plurality of cord-like bodies discretely arranged around the circumference of the longitudinal member, each of which extends parallel or obliquely to the axis of the longitudinal member.
According to another aspect of the present invention, there is provided a chuck that is detachably attached to a longitudinal member in order to pull the longitudinal member out of a support portion or a foundation portion embedded in the support portion, or to pull the longitudinal member out of the support portion together with the foundation portion, the chuck comprising:
a cylindrical contact layer that surrounds the outer peripheral surface of the longitudinal member locally in the axial direction and entirely or partially in the circumferential direction, the contact layer having elasticity at least in the radial direction and a soft material at least in a surface layer, the inner peripheral surface of the contact layer contacting the outer peripheral surface of the longitudinal member;
an outer frame that holds the contact layer in a supporting manner from behind, the outer frame non-invasively gripping the longitudinal member by compressively contacting the contact layer with the outer peripheral surface of the longitudinal member within its elastic range at its inner surface;
The contact layer is provided with a chuck for extracting the longitudinal member, the chuck being constituted by an arrangement of a plurality of discrete bodies arranged discretely in the circumferential direction of the longitudinal member.

According to a first aspect of the present invention , there is provided a chuck removably mounted on an existing longitudinal member for extracting the longitudinal member from a support or a foundation embedded in the support, or for extracting the longitudinal member together with the foundation from the support, comprising:
An outer frame having a plurality of divided bodies arranged in a circumferential direction of the longitudinal member;
a cylindrical contact layer supported on the inner surface of the outer frame, having elasticity at least in the radial direction and having a soft material at least on a surface layer thereof;
a clamping mechanism that clamps the plurality of divided bodies in a circumferential direction to bring the outer frame into contact with the outer circumferential surface of the longitudinal member via the contact layer in a compressed state, thereby clamping the longitudinal member within its elastic range;
A chuck for extracting a longitudinal member is provided in which each segment is configured as a stack of multiple plates extending transversely to the longitudinal member, stacked in the axial direction of the longitudinal member with each plate permitted to slide.

According to a second aspect of the present invention, there is provided a longitudinal member extraction system for extracting an existing longitudinal member from a support or a foundation embedded in the support, or for extracting the existing longitudinal member from the support together with the foundation, the system comprising:
The chuck;
and an axial force applying machine that engages with the chuck and quasi-statically applies an axial force to the chuck in a direction that moves the longitudinal member together with the chuck away from the support portion or the base portion.

According to a third aspect of the present invention, there is provided a method for extracting an existing longitudinal member from a support or a foundation embedded in the support, or from the support together with the foundation, the method comprising the steps of:
a clamping step of clamping the longitudinal member by clamping the longitudinal member within its elastic range using any of the several chucks described above;
and applying an axial force to the chuck in a direction that moves the chuck, together with the longitudinal member, away from the support portion or the base portion.

According to a first aspect of the present invention, there is provided a chuck that is detachably attached to a longitudinal member in order to pull the longitudinal member out of a support portion or a foundation portion embedded in the support portion, or to pull the longitudinal member out of the support portion together with the foundation portion, the chuck comprising:
A chuck for extracting a longitudinal member is provided which grips the longitudinal member non-invasively by tightening the longitudinal member within its elastic range via a tubular contact layer which is elastic at least in the radial direction and has a soft material at least on its surface, with the contact layer surrounding the outer circumferential surface of the longitudinal member entirely or partially.

According to a second aspect of the present invention, there is provided a chuck that is detachably attached to a longitudinal member in order to quasi-statically apply at least an axial force, out of an axial force and a rotational force, to the longitudinal member in order to pull the longitudinal member out of a support portion or a foundation portion embedded in the support portion, or to pull the longitudinal member out of the support portion together with the foundation portion, the chuck comprising:
a cylindrical contact layer that surrounds the outer peripheral surface of the longitudinal member locally in the axial direction and entirely or partially in the circumferential direction, the contact layer having elasticity at least in the radial direction and a soft material at least in a surface layer, the inner peripheral surface of the contact layer contacting the outer peripheral surface of the longitudinal member;
and an outer frame that supports the contact layer from behind;
The contact layer is provided with a longitudinal member extraction chuck that non-invasively grips the longitudinal member by clamping the longitudinal member within its elastic region.

According to a third aspect of the present invention, there is provided a longitudinal member extraction system for extracting an existing longitudinal member from a support or a foundation embedded in the support, or for extracting the existing longitudinal member from the support together with the foundation, the system comprising:
The chuck;
a first unit that engages the chuck and quasi-statically applies an axial force to the chuck in a direction that directs the longitudinal member, together with the longitudinal member, away from the support or the base.

According to a fourth aspect of the present invention, there is provided a method for extracting an existing longitudinal member from a support portion or a foundation portion embedded in the support portion, or for extracting an existing longitudinal member from the support portion together with the foundation portion, the method comprising the steps of:
atraumatically gripping the longitudinal member by clamping the longitudinal member within its elastic range with the chuck;
and quasi-statically applying an axial force to the chuck in a direction that moves the chuck, together with the longitudinal member, away from the support or the base.

According to a fifth aspect of the present invention, there is provided a chuck that is detachably attached to an existing longitudinal member in order to pull the longitudinal member out of its installation location, comprising:
a cylindrical contact layer having elasticity at least in a radial direction and having a soft material at least on a surface thereof;
The contact layer is provided with a chuck for extracting the longitudinal member, which clamps the longitudinal member within its elastic range, with the contact layer surrounding the outer circumferential surface of the longitudinal member entirely or partially.

According to a sixth aspect of the present invention, there is provided a chuck that is detachably attached to an existing longitudinal member in order to pull the longitudinal member out of its installation location, comprising:
a cylindrical contact layer having elasticity at least in a radial direction and having a soft material at least on a surface thereof;
a lever mechanism having a pair of levers connected to a base end portion so as to be swingable on one plane, and at least one of the base end portion and the pair of levers supports the contact layer from behind on its inner surface,
The contact layer is provided with a chuck for extracting the longitudinal member, which clamps the longitudinal member within its elastic range while surrounding the outer circumferential surface of the longitudinal member entirely or partially.

The present invention provides the following aspects. Each aspect is divided into clauses, each clause is numbered, and the numbers of other clauses are cited as necessary. This is to facilitate understanding of some of the technical features that the present invention may employ and their combinations, and should not be construed as limiting the technical features and combinations that the present invention may employ to the following aspects. In other words, it should be construed that there is no prohibition on appropriately extracting and employing technical features that are not described in the following aspects but are described in this specification as technical features of the present invention.

Furthermore, describing each paragraph in a form that refers to the number of other paragraphs does not necessarily mean that it is prohibited to separate and make independent the technical features described in each paragraph from the technical features described in other paragraphs, and it should be interpreted that it is possible to make independent the technical features described in each paragraph as appropriate depending on their nature.

(1) A chuck that is detachably attached to an existing longitudinal member in order to pull the longitudinal member out of a support part or a foundation part embedded in the support part, or to pull the longitudinal member out of the support part together with the foundation part,
A chuck for extracting a longitudinal member, which non-invasively grasps a longitudinal member by tightening the longitudinal member within its elastic range through a cylindrical contact layer that is elastic at least in the radial direction and has a soft material at least on its surface, with the contact layer completely or partially surrounding the outer circumferential surface of the longitudinal member.

(2) A chuck that is detachably attached to a longitudinal member in order to quasi-statically apply at least an axial force, out of an axial force and a rotational force, to the longitudinal member in order to pull the longitudinal member out of a support part or a foundation part embedded in the support part, or to pull the longitudinal member out of the support part together with the foundation part, the chuck comprising:
a cylindrical contact layer that surrounds the outer peripheral surface of the longitudinal member locally in the axial direction and entirely or partially in the circumferential direction, the contact layer having elasticity at least in the radial direction and a soft material at least in a surface layer, the inner peripheral surface of the contact layer contacting the outer peripheral surface of the longitudinal member;
and an outer frame that supports the contact layer from behind;
The contact layer non-invasively grips the longitudinal member by clamping the longitudinal member within its elastic range.

(3) A chuck for extracting a longitudinal member according to paragraph (2), in which the contact layer non-invasively contacts the outer peripheral surface of the longitudinal member under mechanical conditions such that no indentation is substantially left on the portion of the longitudinal member that was gripped by the chuck after the chuck is released from the longitudinal member.

(4) A chuck for extracting a longitudinal member according to any one of items (1) to (3), in which the contact layer includes a soft material as its surface layer material.

(5) A chuck for extracting a longitudinal member according to paragraph (4), in which the soft material includes an elastic body, a synthetic resin, an elastomer, or rubber.

(6) The contact layer has a higher compressive deformation characteristic than when the contact layer is formed as a single piece of metal; and
The chuck for extracting a long member according to any one of (1) to (5), wherein the contact layer has a higher bending deformation characteristic than when the contact layer is formed as a single metal part.

(7) A chuck for extracting a longitudinal member as described in (6), in which the contact layer includes, as its surface material, a soft material having higher compressive deformation characteristics than when the contact layer is constructed as a single metal part.

(8) A chuck for extracting a longitudinal member according to item (2) or (3), in which the outer frame has a low elastic deformation portion that is easily elastically deformed in the radial direction in response to a radial force, and a high elastic deformation portion that is not easily elastically deformed in the radial direction in response to a radial force, each of which is located in a position that supports the contact layer from behind and at a different axial position from each other.

(9) The outer frame has a low elastic deformation portion that is easily elastically deformed in the radial direction against a radial force and a high elastic deformation portion that is not easily elastically deformed in the radial direction against a radial force, the low elastic deformation portion being located at different axial positions from each other,
the outer frame has a support surface that contacts and receives the interface layer from behind;
The support surface has a first partial support surface corresponding to the low elastic deformation portion and a second partial support surface corresponding to the high elastic deformation portion,
each of the first and second partial support surfaces having a distal portion furthest from the contact layer;
The chuck for extracting a longitudinal member according to claim 2 or 3, wherein the distal portion of the first partial support surface is closer to the outer surface of the longitudinal member than the distal portion of the second partial support surface.

(10) In the case where the outer frame is divided into a plurality of divided bodies arranged in a circumferential direction of the longitudinal member, the chuck further includes a first force conversion mechanism that converts a part of a fastening force acting on the plurality of divided bodies when the plurality of divided bodies are connected and fastened to the longitudinal member into a radial force and causes the radial force to act on the contact layer;
A chuck for extracting a longitudinal member as described in (2) or (3), which employs at least one of the following: when a load acting from the outside on the outer frame to extract the longitudinal member is an eccentric load acting in a linear direction offset from the axis of the longitudinal member, the chuck further includes a second force conversion mechanism that converts a portion of the eccentric load into a radial force and applies it to the contact layer.

(11) The outer frame is divided into a plurality of divided bodies arranged in a circumferential direction of the longitudinal member,
The chuck for extracting a longitudinal member according to claim 2 or 3, wherein the divided bodies are connected to each other by a clamping mechanism.

(12) The chuck for extracting a longitudinal member according to item (11), wherein the plurality of divided bodies are four divided bodies in which the outer frame is divided at substantially equal angles.

(13) The clamp mechanism connects two adjacent divided bodies to each other,
The chuck for extracting a longitudinal member according to claim 11 or 12, wherein the clamping mechanism includes an inclined member extending at a connection point thereof in a direction inclined with respect to a tangential direction about the axis of the longitudinal member.

(14) A chuck for extracting a longitudinal member according to (2) or (3), in which the outer frame is configured not as a block extending in the axial direction of the longitudinal member, but as a laminate of multiple plates extending in a direction transverse to the longitudinal member, stacked in the axial direction of the longitudinal member while allowing the sliding and tilting movements of each individual plate.

(15) A chuck for extracting a longitudinal member according to any one of items (1) to (14), in which when the contact layer contains a soft material as its surface layer material, the contact layer adopts a double structure in which a metal is used as a back plate that supports the soft material from behind.

(16) The contact layer is formed of a plurality of cords arranged to extend generally parallel to each other,
A chuck for extracting a longitudinal member according to any one of claims (1) to (15), wherein the string-like bodies are arranged so as to extend parallel to the axis of the longitudinal member or spirally around the axis along an imaginary cylindrical surface that is substantially concentric with the longitudinal member in the compressed state.

(17) A chuck for extracting a longitudinal member according to item (16), in which each of the string-like bodies includes a core material made mainly of metal and a coating layer covering the core material, the coating layer being made mainly of a soft material.

(18) A chuck for extracting a longitudinal member according to item (17), in which the soft material includes an elastic body, a synthetic resin, an elastomer, or rubber.

(19) Each of the cord-like bodies is made of a resin-coated wire rope in which a wire rope is coated with a synthetic resin,
The chuck for extracting a longitudinal member according to claim 17 or 18, wherein the resin-coated wire rope extends generally linearly in a natural state when not attached to the chuck.

(20) The coating layer has a higher surface friction coefficient than the core material,
The chuck for extracting a longitudinal member according to any one of items (17) to (19), wherein the core material has a higher elastic recovery than the coating layer.

(21) A chuck for extracting a longitudinal member according to any one of items (16) to (20), in which the contact layer includes a plurality of grooves on its outer surface that partially accommodate the plurality of string-like bodies behind them.

(22) A chuck for extracting a longitudinal member as described in (21), in which at least some of the plurality of grooves include a depth change portion whose depth changes in the longitudinal direction.

(23) The outer frame has a low elastic deformation portion that is easily elastically deformed in the radial direction against a radial force and a high elastic deformation portion that is not easily elastically deformed in the radial direction against a radial force, at different axial positions from each other,
the outer frame has a plurality of grooves that contact the plurality of string-like bodies from behind and accommodate the string-like bodies,
Each groove has a shallow groove corresponding to the low elastic deformation portion and a deep groove corresponding to the high elastic deformation portion,
each of the shallow grooves and the deep grooves has a distal portion furthest from an outer surface of the post;
The chuck for extracting a longitudinal member according to claim 2 or 3, wherein the distal portion of the shallow groove is closer to the outer surface of the longitudinal member than the distal portion of the deep groove.

(24) A chuck for extracting a longitudinal member according to any one of items (1) to (23), in which the longitudinal member is hollow or solid.

(25) A chuck for extracting a longitudinal member according to any one of items (1) to (24), in which the longitudinal member is made of metal or concrete.

(26) A chuck for extracting a longitudinal member according to any one of items (1) to (25), in which the longitudinal member is a rod, shaft, tube, or cylinder.

(27) A chuck for extracting a longitudinal member according to any one of items (1) to (26), in which the longitudinal member is a pillar, a pile, a beam, or a reinforcing bar.

(28) A chuck for extracting a longitudinal member according to any one of items (1) to (27), wherein the support portion is soil or a wall.

(29) A longitudinal member extraction system for extracting an existing longitudinal member from a support or a foundation embedded in the support, or for extracting the existing longitudinal member from the support together with the foundation, comprising:
A chuck according to any one of (1) to (28) above;
a first unit that engages with the chuck and quasi-statically applies an axial force to the chuck in a direction that moves the longitudinal member together with the chuck away from the support portion or the base portion.

(30) Furthermore,
The longitudinal member extraction system according to claim (29), further comprising a second unit which engages with the chuck and quasi-statically applies an additional axial force to the chuck in a direction that moves the chuck and the longitudinal member away from the support or the base when the longitudinal member cannot be extracted from the support or the base by using only the first unit.

(31) The longitudinal member is embedded in the base portion,
The longitudinal member extraction system further comprises:
A longitudinal member extraction system as described in (29) or (30), which includes a displacement restraint device that holds the base portion so that the base portion does not displace from its original position as the longitudinal member is extracted, so that the longitudinal member can be extracted from the base portion while leaving the base portion in its original position.

(32) A method for extracting a longitudinal member from the support part or the base part using the longitudinal member extraction system according to (29), comprising:
atraumatically gripping the longitudinal member by clamping the longitudinal member within its elastic range with the chuck;
placing the first unit into engagement with the chuck;
and a step of quasi-statically applying an axial force to the chuck in a direction to move the chuck together with the longitudinal member away from the support portion or the base portion by driving the first unit.

(33) A method for extracting a longitudinal member from the support part or the base part using the longitudinal member extraction system according to (30), comprising:
atraumatically gripping the longitudinal member by clamping the longitudinal member within its elastic range with the chuck;
placing the first unit into engagement with the chuck;
applying an axial force to the chuck in a direction to move the chuck together with the elongate member away from the support as a quasi-static force rather than an impulsive force by driving the first unit;
placing the second unit in engagement with the chuck when the first unit alone is not sufficient to completely withdraw the longitudinal member from the support or the base;
and a step of quasi-statically applying an axial force to the chuck in a direction to move the chuck together with the longitudinal member away from the support portion or the base portion by driving the second unit.

(34) A method for extracting a longitudinal member according to (32) or (33), which does not include a step of rotating the chuck integrally with the longitudinal member.

(35) A chuck for extracting a longitudinal member according to (4) or (5), in which when the longitudinal member is a rigid body, the contact between the longitudinal member and the contact layer appears as rigid-soft body contact, and the rigid-soft body contact improves the fit of the surface of the contact layer to the surface of the longitudinal member more easily than contact between rigid bodies.

(36) A chuck for extracting a longitudinal member according to any one of items (1) to (28), which is configured to have a shape that fits the shape of a straight portion, a curved portion, or an angle portion of the longitudinal member, so that the chuck can be attached to the straight portion, the curved portion, or the angle portion of the longitudinal member, if the longitudinal member has such a straight portion, if the longitudinal member has such a curved portion, or to the angle portion, if the longitudinal member has such an angled portion.

(37) A chuck for extracting a longitudinal member according to any one of items (1) to (28), in which the longitudinal member has a hollow structure and is configured to have a closed or open cross-sectional shape.

(38) A chuck for extracting a longitudinal member according to any one of items (1) to (28), in which the longitudinal member has a hollow structure or a solid structure, and is configured to have an outer peripheral surface that is continuous in the circumferential direction or an outer peripheral surface that has a discontinuous portion in the circumferential direction.

FIG. 1 is an exploded perspective view of a cylinder extraction system according to an exemplary embodiment of the present invention. FIG. 2(a) is a perspective view showing the column, the chuck and the base before extraction when the column extraction method is carried out using the column extraction system shown in FIG. 1, and FIG. 2(b) is a perspective view showing the column, the chuck and the base after extraction. FIG. 3 is a side view for explaining a process of mounting the chuck to the column body using a base unit and a mounting jig at a stage before extraction. FIG. 4 is a perspective view showing the base unit shown in FIG. FIG. 5 is a side view for explaining a process of installing a jack between the chuck and the base unit at a stage before the extraction. FIG. 6 is an enlarged side view of the jack shown in FIG. FIG. 7 is a side view for explaining an additional pulling-out operation using a hoist as a second-stage pulling-out operation after the pulling-out operation using a jack as a first-stage pulling-out operation is completed. FIG. 8 is a side view illustrating three installation methods of the pillar body according to the embodiment shown in FIG. 1. Specifically, FIG. 8(a) shows a first installation method in which the pillar body is buried and fixed in a foundation section buried in the ground, FIG. 8(b) shows a second installation method in which the pillar body is buried and fixed directly in the ground, and FIG. 8(c) shows a third installation method in which the pillar body is buried and fixed in a state in which the bottom end of the pillar body is joined to a foundation section buried in the ground in a position in which the expanded bottom section is exposed from the foundation section. FIG. 9 is a perspective view showing an enlarged representative example of one of the divided bodies shown in FIG. FIG. 10 is a side cross-sectional view showing the divided body shown in FIG. FIG. 11A is a partial cross-sectional side view for explaining, as a comparative example, the behavior of an outer frame responding to an eccentric load when the outer frame of the chuck is of a one-piece type, and FIG. 11B is a partial cross-sectional side view for explaining, as an example, the behavior of the outer frame responding to an eccentric load when the outer frame of the chuck is of a laminated type. FIG. 12 is an enlarged partial plan view showing a large plate among the multiple plates that constitute the divided body shown in FIG. 9 in a stacked state, together with the other three divided bodies assembled thereto. FIG. 13 is an enlarged plan view of a small plate among the multiple plates that constitute the divided body shown in FIG. 9 in a stacked state, together with the other three divided bodies assembled thereto. Figure 14(a) is a plan view showing the small plate shown in Figure 13 virtually superimposed on the large plate shown in Figure 12 for comparison, and Figure 14(b) is a plan view for illustrative purposes of an arc shape different from the arc shape of the small plate shown in Figure 14(a). Figure 15(a) is an enlarged plan view showing one of the multiple deep grooves in the large plate shown in Figure 12 and one of the multiple shallow grooves in the small plate shown in Figure 13, which corresponds to the one deep groove, as viewed from directly above the stack shown in Figure 9; Figure 15(b) is a front view showing multiple plates having these deep grooves and shallow grooves; Figure 15(c) is a side cross-sectional view showing multiple plates having these deep grooves and shallow grooves; and Figure 15(d) is a cross-sectional view showing the string-like body shown in Figure 1 being accommodated in the shallow groove in a state where it is elastically crushed by compression by a cylinder. FIG. 16 is an enlarged perspective view of the string-like body shown in FIG. Figures 17(a) and (b) are cross-sectional views showing an example of the structure of the contact layer shown in Figure 1, in which a plurality of string-like bodies, each having a circular cross-section, are arranged along an imaginary cylindrical surface concentric with the cylinder as a plurality of discrete bodies discretely arranged in the circumferential direction of the cylinder. Figures 17(c) and (d) are cross-sectional views showing another example, in which a plurality of string-like bodies, each having an oval cross-section, are arranged along an imaginary cylindrical surface concentric with the cylinder as a plurality of discrete bodies discretely arranged in the circumferential direction of the cylinder. Figure 17(e) is a cross-sectional view showing, as yet another example, a structure in which a cylindrical body (sleeve) continuous in the circumferential direction of the cylinder extends axially along an imaginary cylindrical surface concentric with the cylinder. 18A is a plan view showing a first circumferential clamp portion used at the multiple clamp positions A in FIG. 12 of the clamp mechanism shown in FIG. 1, and FIG. 18B is a side view. 19A is a plan view showing a second circumferential clamp portion used at the multiple clamp positions B in FIG. 12 of the clamp mechanism shown in FIG. 1, and FIG. 19B is a side view. FIG. 20(a) is a plan view showing a chuck suitable for a rectangular prism or a rectangular tube, which is another example of a cylindrical body, and FIG. 20(b) is an enlarged plan view showing the contact layer shown in FIG. 20(a). FIG. 21 is a process diagram showing an example of a method for extracting a cylinder body using the cylinder body extraction system shown in FIG. FIG. 22 is a graph conceptually showing an example of a tendency of the lifting force of a jack over time in a pulling-out work process using a jack when carrying out the cylinder body pulling-out method shown in FIG. 21 . FIG. 23 is a perspective view showing an example of a removal site where an obstacle exists near an installed column, so that the clearance required to attach a chuck to the column is insufficient. FIG. 24 is a perspective view showing an example of an asymmetric hinge assembly-type chuck that can be attached to a pillar body at the removal site shown in FIG. 23.

Some of the more specific exemplary embodiments of the present invention will be described in detail below with reference to the drawings.

Figure 1 shows an exploded perspective view of a column extraction system (an example of a "longitudinal member extraction system" hereinafter referred to as "the system") 10 according to an exemplary embodiment of the present invention.

<<System Use>>

As shown in the figure, this system 10 is used to pull out and remove an existing column body (an example of a "longitudinal member") 12 from its installation location.

Specifically, as shown in the figure and in Figure 2, this system 10 is used to pull out and remove an existing column body 12 that is embedded in a foundation 14 (e.g., made of concrete, mortar, or a material containing cement as a main component) that is buried in the ground, from the foundation 14 while leaving the foundation 14 in the ground.

＜＜Basic system configuration＞＞

As shown in Figures 1 and 3-7, this system 10 includes a chuck 20 that grips the column body 12 non-invasively and with a full-circumference elastic fastening method, an attachment jig 22 that assists in attaching the chuck 20 to the column body 12, a base unit 24 that prevents the base part 14 from rising together with the column body 12 during the column body 12 extraction operation, and a jack 26 that applies an axial force to the column body 12 via the chuck 20 to extract the column body 12 from the base part 14.

The system 10 further includes a hoist 30 that applies additional axial force to the column 12 via the chuck 20 to pull the column 12 out of the base 14, and a multi-tiered stacking scaffold 32 on which the hoist 30 is installed, for example, in a suspended state.

In this system 10, as shown in Figures 1, 5, and 11, the load acting from the outside on the chuck 20 to extract the cylinder 12 is a concentrated eccentric load acting in a linear direction offset from the axis of the cylinder 12.

<<Multiple objectives achieved by the system>>

1. Making the extraction process non-destructive and reducing vibration and noise

In this embodiment, the column body 12 is pulled out from the foundation part 14 without using heavy machinery such as a small crane for the extraction work, and without the need to destroy the foundation part 14 using a vibrating tool or the like. Furthermore, the column body 12 is pulled out from the foundation part 14 without applying an impact load to the column body 12. This makes the extraction work and the associated equipment removal work non-destructive and reduces vibration and noise, so that the work is carried out without causing inconvenience to nearby residents.

2. Reducing the amount of work required (man-hours and construction time)

In this embodiment, the column body 12 is pulled out from the foundation 14 without the need to bring in large equipment or heavy machinery to the site or to destroy the foundation 14. Furthermore, the equipment required for the work is disassembled and assembled, reducing the space occupied inside the transport vehicle during loading and unloading, making these operations easier. This reduces the labor required for the overall removal work, including the pulling out work.

3. Simplification of work and equipment and reduction of work costs

In this embodiment, the column body 12 is pulled out without using special or large equipment, for example, using a handheld manual lifting machine, lifting machine, or push-up machine (e.g., a manual jack 26 or a manual hoist 30) or a chuck 20 that can be disassembled and assembled on-site. This makes it easy to simplify the work and equipment and reduce work costs.

4. Reusing the extracted columns

In this embodiment, the column 12 is extracted non-invasively with the chuck 20, i.e., so that no irreparable marks such as indentations remain on the column 12 after extraction. Because the column 12 is extracted non-invasively, the same column 12 can be reused at another site without additional repairs, enabling effective use of resources and reducing equipment costs at other sites.

<<Basic structure of chuck>>

<Basic principles>

Generally, the chuck 20 is removably, elastically, and non-invasively attached to the column 12 in order to quasi-statically apply at least an axial force, out of an axial force and a rotational force, to the column 12 in order to pull the existing column 12 out of its installation location (the base 14 in the example shown in the figure).

＜Contact layer＞

The chuck 20 has elasticity at least in the radial direction (at least the former of radial elasticity (compressive elasticity) and longitudinal elasticity (flexural elasticity)) and has a cylindrical contact layer 40 (described in detail later with reference to Figures 16 and 17) that has a soft material at least on the surface. When the column 12 is a cylindrical body or a cylindrical body, the "cylindrical contact layer" is configured as a cylindrical contact surface or a cylindrical contact surface.

The chuck 20 is configured to elastically compress and contact the outer peripheral surface of the cylinder 12 through the contact layer 40, with the contact layer 40 surrounding the outer peripheral surface of the cylinder 12 substantially entirely (or partially or locally in an area shorter than one circumference of the outer peripheral surface).

The chuck 20 is thus configured to grip the cylinder 12 non-invasively by clamping the cylinder 12 within its elastic range so as to leave substantially no indentation on its outer circumferential surface. Thus, the chuck 20 can be called a "full-circumference elastic clamping chuck."

＜Outer frame＞

The chuck 20 further includes an outer frame 50 (described in more detail later with reference to Figures 9-15) that supports and holds the contact layer 40 from behind.

The outer frame 50 is divided into a number of segments 52 arranged in the circumferential direction of the column 12. Each segment 52 is constructed as a stack of a number of plates. The plates are identical to each other in terms of thickness and material, but may alternatively be constructed to have different thicknesses or materials depending on the axial position, for example.

＜Clamping mechanism＞

In order to assemble the divided bodies 52 in a state where the chuck 20 grips the column body 12, the chuck 20 is provided with a clamping mechanism 80 (described in detail later with reference to Figures 18 and 19) that removably connects the divided bodies 52 in the circumferential direction at multiple positions in a plan view.

<<Basic features of chucks>>

An important performance characteristic of the chuck 20 is that a large frictional force is generated between the inner surface of the chuck 20 and the outer surface of the cylinder 12 in relation to the size of the device and the magnitude of the load. On the other hand, the frictional force generally increases according to the product of the surface friction coefficient, the drag (radial stress), and the effective contact area.

1. Measures to increase the surface friction coefficient of the contact layer 40

The contact layer 40 uses a soft material as its surface layer material (for example, the material of the covering layer 42 described below). The soft material includes an elastic body, a synthetic resin, an elastomer, or a rubber.

2. Optional measures to increase the contact area between the pillar 12 and the contact layer 40

(1) The contact layer 40 has higher compressive deformation characteristics than when it is constructed as a single metal part, thereby increasing the radial conformability of the contact layer 40 to the outer surface of the column 12. For example, the contact layer 40 uses a soft material that is easily crushed and flattened by the load of radial force from the outer frame 50.

(2) The contact layer 40 has higher bending deformation characteristics than when it is constructed as a single metal part, thereby increasing the axial conformity of the contact layer 40 to the outer surface of the column 12. For example, the contact layer 40 uses a soft material that is easily bent by the bending moment load from the jack 26.

(3) The outer frame 50 has a low elastic deformation portion (e.g., a small plate 54 as a narrow plate described below) that is easily elastically deformed in the radial direction in response to a radial force, and a high elastic deformation portion (e.g., a large plate 56 as a wide plate described below) that is not easily elastically deformed in the radial direction in response to a radial force, each of which is located in a position that supports the contact layer 40 from behind and in a different axial position from each other, thereby increasing the axial conformability of the contact layer 40 to the outer surface of the column 12.

(4) The outer frame 50 has a support surface (e.g., multiple vertical grooves 58 described below) that contacts the contact layer 40 from behind and accommodates it. The support surface has a first partial support surface (e.g., shallow groove 60 described below) that corresponds to the low elastic deformation portion, and a second partial support surface (e.g., deep groove 62 described below) that corresponds to the high elastic deformation portion. Both the shallow groove 60 and the deep groove 62 have distal portions 64, 66 that are furthest from the contact layer 40.

As a result, the portion of the contact layer 40 that corresponds to the low elastic deformation portion is radially compressed to a greater extent in the compressed state than the portion that corresponds to the high elastic deformation portion. This causes the contact layer 40 to be flattened and crushed to a greater extent in the circumferential direction, thereby increasing the contact area between the column 12 and the contact layer 40.

3. Optional measures to increase the drag acting on the contact layer 40

(1) When the outer frame 50 is divided into multiple segments 52 arranged in the circumferential direction of the column 12, the chuck 20 further includes a first force conversion mechanism that converts a portion of the fastening force acting on the multiple segments 52 when the multiple segments 52 are connected to each other and fastened to the column 12 into a radial force and applies it to the contact layer 40.

The first force conversion mechanism includes a diagonal member (a second circumferential clamping portion, described later) of the clamping mechanism 80 that extends in a direction inclined with respect to the tangent direction at the clamping position B. The diagonal member converts a part of the fastening force acting on the multiple segments 52 when the multiple segments 52 are connected to each other and fastened to the column 12 into a radial force. This equalizes the resistance acting on the contact layer 40 by the outer frame 50 in the circumferential direction of the contact layer 40, and as a result, it is expected that the total sum of the resistance in the circumferential direction will increase.

(2) The chuck 20 includes a second force conversion mechanism that converts a portion of the eccentric load into a radial force and applies it to the contact layer 40.

The second force conversion mechanism includes a laminated structure of the outer frame 50.

Specifically, the outer frame 50 is not configured as a block extending in the axial direction of the column 12, but as a laminate, i.e., as a laminate of multiple plates 54, 56 extending in a direction transverse to the column 12, stacked in the axial direction of the column 12 while allowing the individual plates to slide and tilt.

When the eccentric load acts on the laminate, the inner end faces of the plates 54, 56 undergo sliding deformation and tilting in a direction that fits into the axial region of the contact layer 40. This is believed to contribute to realizing a state in which the laminate contacts the axial region of the contact layer 40 over as long a portion as possible. As a result, even though the eccentric load acts on the outer frame 50, the resistance acting on the contact layer 40 by the outer frame 50 is equalized in the axial direction of the contact layer 40, and as a result, it is expected that the total sum of the resistance in the axial direction will increase.

4. Measures to increase the durability of the contact layer 40 when the contact layer 40 uses a soft material as its surface material

The contact layer 40 has a double structure in which a metal backing plate supports the soft material from behind.

5. Measures to prevent the string-like body 44 described below from unintentionally falling out of the vertical groove 58 of the chuck 20 before tightening

At least some of the multiple longitudinal grooves 58 include a depth change portion whose depth changes in the longitudinal direction. The depth change portion is, for example, a portion where a shallow groove 60 and a deep groove 62 (described later) contact each other in the longitudinal direction of the longitudinal groove 58.

The depth change portion acts as a retainer that prevents the corresponding string-like body 44 from axially detaching from at least a portion of the longitudinal groove 58.

An exemplary and specific component configuration of this chuck 20 will be described in detail later.

＜＜Jack＞＞

The system 10 further includes a jack 26 (an example of a "first unit") that applies an upward force to the chuck 20 on its downward surface or other portion to pull the column 12 out of the base 14 via the chuck 20.

The jack 26 uses a manual type as the driving source (driving method), but instead of this, a fluid type or a motor type may be used. Also, the jack 26 uses a hydraulic type as the boosting method, but instead of this, a lever type, a screw type, a motor type, a compressed air type, or a partial or total combination of these may be used. Also, the jack 26 uses a direct operation type as the operating method, but instead of this, a remote control type may be used.

Figure 6 shows a side view of the jack 26. A jack similar to the jack 26 is disclosed, for example, in JP 2002-87767 A.

The jack 26 has a generally plate-shaped base 90 that extends horizontally, and a hollow cylindrical (bottle-shaped with a bottom at the top) housing 92 that stands on the base 90. A cylinder 94 is disposed within the housing 92, thereby dividing the internal space of the housing 92 into the space within the cylinder 94 and a tank chamber 96 outside the cylinder.

A ram 100 is fitted in the internal space of the cylinder 94 in a liquid-tight and slidable manner, thereby forming a hydraulic chamber 102 between the lower end of the ram 100 and the base 90 or the housing 92. The tank chamber 96 and the hydraulic chamber 102 are filled with a common hydraulic fluid (such as oil).

The ram 100 extends perpendicular to the base 90. The upper end of the ram 100 protrudes from the housing 92, and the ram 100 can engage the chuck 20 at its protruding end (e.g., a receiving frame).

The jack 26 further has a pump 104, which is also attached to the base 90. A plunger 106 is fitted to the pump 104 in a liquid-tight and slidable manner, and a pressurized chamber 108 is formed between one end of the plunger 106 and the base 90. The pressurized chamber 108 is fluidly connected to the hydraulic chamber 102 and the tank chamber 96 via a plurality of valve units 110 (e.g., a plurality of check valves) that control the flow direction of the hydraulic fluid.

The other end of the plunger 106 protrudes from the pump 104. The protruding end is pivotally connected to one end of a socket 114 (e.g., a sleeve for a handle) that is pivotally connected around a pin 112 fixed to the housing 92 or base 90.

A lever 116 (e.g., a handle) that can be moved up and down by an operator is removably inserted into the socket 114. The operator pressurizes the hydraulic chamber 102 by repeatedly rocking the lever 116 up and down, and the pressure in the hydraulic chamber 102 acts on the ram 100.

When the hydraulic chamber 102 is not pressurized, the ram 100 is in its maximum contraction position, i.e., its lowest position, as shown by the solid line in the figure.

In contrast, when the lever 116 is operated to drive the jack 26 and the hydraulic chamber is pressurized, the ram 100 can rise to its maximum extension position, i.e., its highest position, as indicated by the two-dot chain line in the figure. At this time, the ram 100 applies an upward force as lift to the chuck 20 that is engaged with it. The difference between the highest and lowest positions of the ram 100 is the lift range.

<<Base unit>>

As illustrated in FIG. 3, the system 10 further includes a base unit 24 (an example of a "displacement prevention unit") that is placed so as to at least partially cover the foundation 14 in order to mechanically prevent the foundation 14 from lifting out of the soil as the column 12 is pulled out.

As shown in FIG. 4, the base unit 24 is configured as a disassembly type so that it can be assembled and disassembled on-site. The base unit 24 has a hollow structure, and the column 12 can pass through its center. The base unit 24 has a base that is placed on the foundation 14 so as to at least partially cover the foundation 14.

<<Installation jig>>

As shown in FIG. 3, the system 10 further includes an attachment jig 22 for supporting the chuck 20 from below before assembly, in order to assist the worker in attaching the chuck 20 to the column body 12. The attachment jig 22 has a hollow structure, and its lower surface contacts the upper surface of the base unit 24, while its upper surface supports the lower surface of the chuck 20.

The worker uses this mounting jig 22 to provisionally position the chuck 20 relative to the column body 12 in both the axial and radial directions, and then uses a clamping mechanism 80 (see Figures 1, 18, and 19) to clamp the multiple segments 52 together with the column body 12, thereby assembling the chuck 20 to the column body 12.

This mounting jig 22 may also be configured as a disassembly and assembly type so that it can be assembled and disassembled on-site.

<<Hoist>>

As shown in FIG. 7, the system 10 further includes a hoist 30 (or winch) (an example of a "second unit") that applies additional upward force to the chuck 20 when the lifting height of the jack 26 alone is insufficient to allow the column 12 to be peeled off and partially pulled out from the base 14 but not completely pulled out.

The hoist 30 has, for example, a chain block, and is connected to an eyebolt 124 (see FIG. 7) that serves as a connector for the chuck 20 using a chain 120 and a hook 122 connected to the end of the chain 120, thereby lifting the chuck 20 together with the column body 12 by winding up and pulling up the chain 120, thereby pulling the column body 12 within the base part 14 and finally removing it from the base part 14.

The hoist 30 employs a manual type as the driving source (driving method), but instead of this, a motor type, a hydraulic type, a compressed air type, or a partial or total combination of these may be employed. Also, the hoist 30 employs a direct operation type as the operating method, but instead of this, a remote control type may be employed.

<<Multi-layered stacking scaffolding>>

As shown in FIG. 7, the system 10 further includes multiple levels of scaffolding 32 on which the hoist 30 is installed in order to elevate the installation position of the hoist 30. The scaffolding 32 shown in solid lines in the figure indicates the first level of scaffolding 32. To elevate the installation position of the hoist 30 even further, the second level of scaffolding 32 is installed by stacking it on top of the first level of scaffolding 32, as shown in dashed double-dashed lines in the figure. Each scaffolding 32 is configured as a disassembly type that can be assembled and disassembled on-site.

[Example and specific component configuration of a chuck]

＜＜Outer frame＞＞

As shown in Figure 9, which is a representative enlarged perspective view of one of the multiple divisions 52 shown in Figure 1, the outer frame 50 is not a single block (e.g., a metal block) extending in the axial direction of the column body 12, but is configured as a laminate in which multiple plates 54, 56 extending in a direction transverse to the column body 12 are stacked in the axial direction of the column body 12.

As shown in the figure, the multiple plates 54, 56 are composed of multiple (four in the illustrated example) large plates 56 (see FIG. 12) and multiple small plates 54 (see FIG. 13). Regardless of the type, one circumference of each plate 54, 56 is divided into an inner edge closest to the outer surface of the cylinder 12, an outer edge furthest away, and a right edge and a left edge located respectively to the right and left of the center of the cylinder 12.

As shown in Figures 9 and 10, a number of small plates 54 are divided into three groups by a number of large plates 56, and in each group, a number of stacked small plates 54 are sandwiched between two adjacent large plates 56.

As shown in FIG. 12, multiple through holes are formed in each of the multiple large plates 56 so that the large plates 56 can be stacked and fastened in a predetermined relative positional relationship. Some of the through holes are arranged on multiple radial lines (shown by dashed lines in the figure) extending at equal angles from the center of the chuck 20 so that the fastening force of the multiple segments 52 is uniform in the circumferential direction.

Some of the multiple through holes are formed in each large plate 56 at multiple positions D, E, F, G, H1, H2 and J.

Specifically, for each large plate 56, two positions D are located at both ends of the inner edge of each large plate 56. Also, for each large plate 56, one position E is located in the center of the outer edge of each large plate 56.

Furthermore, for each large plate 56, one position F is located approximately in the center of the right edge of the large plate 56. Further, for each large plate 56, one position G is located approximately in the center of the left edge of the large plate 56, and position G differs from position F in terms of the distance from the center of the column 12. In other words, position F and position G are positioned so as not to exist on concentric circles.

For each large plate 56, the two positions H1 are located at both ends of the outer edge of the large plate 56. For each large plate 56, the two positions H2 are located at both ends of the outer edge of the large plate 56, similar to the two positions H1, but the positions H2 are different from the positions H1 in terms of the distance from the center of the column 12.

Furthermore, for each large plate 56, the two positions J are located circumferentially inward of the left pair of positions H1 and H2 and the right pair of positions H1 and H2 on the same large plate 56, respectively.

Specifically, groups consisting of positions H1, H2, and J, which are located at the three vertices of a roughly equilateral triangle, are arranged on both sides of the outer periphery, and these two groups are arranged symmetrically on the left and right sides of the same large plate 56 with respect to its center line (a straight line passing through the central angular position of each large plate 56 (shown as "center" in the figure) and position E).

As shown in FIG. 10, the small plates 54 are stacked in the axial direction of the outer frame 50 (the thickness direction of each small plate 54), and in order to fasten them in a state in which they have a predetermined circumferential positional relationship with the large plate 56, as shown in FIG. 13, multiple through holes are formed in each small plate 54. The through holes are formed at position K, which is concentric with position D shown in FIG. 12.

As shown in the side cross-sectional view of FIG. 10, the large plate 56 and the small plate 54 are fastened together in a stacked state by passing rod-shaped fasteners 130 through predetermined ones of the multiple through holes. Examples of rod-shaped fasteners 130 include shafts (without threads) or long screws (threaded at least on both ends), and other examples include nuts and eye bolts.

In the figure, long screws are inserted as rod-shaped fasteners 130 through multiple large plates 56 and multiple small plates 54 at position D (position K), and nuts 132 are fastened to the ends of the long screws that protrude from the two outermost large plates 56. Similarly, long screws are inserted as rod-shaped fasteners 130 through multiple large plates 56 at position E, and nuts 132 are fastened to the ends of the long screws that protrude from the two outermost large plates 56.

In this case, a spacer 134 (sleeve or collar) is placed between two adjacent large plates 56, with the rod-shaped fastener 130 passing through it. This defines the axial distance between the two adjacent large plates 56.

As shown in the figure, a gap (meaning the difference between the maximum outer diameter of the threaded portion of the rod-shaped fastener 130 and the minimum inner diameter of the through hole, hereafter referred to as "thread gap") remains between each rod-shaped fastener 130 and each through hole. The thread gap is about 1 mm in diameter, and is, for example, class 2 or higher in terms of hole diameter grade.

<Effects of constructing the outer frame as a laminated body capable of sliding motion>

As explained above, the outer frame 50 is constructed as a laminate, and the multiple plates 54, 56, each of which is a thin plate, are fastened to each other with a relatively large screw clearance to form a laminate capable of sliding movement. We will consider the effects of this.

Figure 11(a) shows, as a comparative example, a partial cross-sectional side view of the analysis results of the behavior of the outer frame 50 of the chuck 20 in response to the eccentric load when the outer frame 50 is one-piece (block).

In this comparative example, as in the embodiment described later with reference to FIG. 1(b), eccentric loads act in parallel and upward on the outer frame 50 from a pair of jacks 26 facing each other across the column 12. Due to each eccentric load, bending moments act on the outer frame 50 in opposite directions.

In this comparative example, as in the example, it is assumed that the radial forces acting on the outer frame 50 due to the respective bending moments are distributed in a non-uniform pattern in the axial direction of the outer frame 50, increasing from a proximal point (contact point (point of force), lowest point) of the outer frame 50 relative to the jack 26 toward a distal point (highest point).

Under these mechanical conditions, in this comparative example, the outer frame 50 is configured as a rigid metal block. Therefore, in this comparative example, the outer frame 50 tilts (angularly displaces) in response to the bending moment without deforming itself.

As a result, the outer frame 50 undergoes a rigid-body displacement (angular displacement, i.e., tilting of the entire rigid body) in a direction that moves the outer frame 50 radially outward away from the outer surface of the cylinder 12 at its proximal point, while moving radially inward toward the outer surface of the cylinder 12 at its distal point.

Therefore, in this comparative example, it is assumed that the chuck 20 is locally lifted from the outer surface of the cylinder 12 at its proximal point. This emphasizes the non-uniformity of the distribution pattern of the radial force acting on the outer frame 50.

As a result, in this comparative example, it is presumed that the resistance generated in the contact layer 40 is locally reduced at the proximal point, the frictional force between the contact layer 40 and the cylinder 12 is also locally reduced, and thus the total axial resistance generated in the contact layer 40 is also reduced.

In contrast, FIG. 1B shows, as an embodiment of the present invention, a partial cross-sectional side view of the analysis results of the behavior of the outer frame 50 of the chuck 20 in response to an eccentric load when the outer frame 50 is a laminate capable of sliding motion.

In this embodiment, when the eccentric load acts on the outer frame 50 as a laminate capable of sliding motion, it is assumed that the bending moment causes individual sliding motion and tilting of the multiple plates 54, 56. As a result, it is assumed that sliding deformation and tilting occur overall in the outer frame 50 itself, and that this causes the contact layer 40 to be maintained in a state in which its inner surface is in overall contact with the outer surface of the column 12 in the axial direction.

As a result, even though the eccentric load acts on the outer frame 50, the area of the axial region where the contact layer 40 contacts the outer surface of the column 12 is prevented from decreasing, and the non-uniformity of the distribution pattern of the radial force acting on the outer frame 50 is prevented from being accentuated. As a result, it is presumed that the resistance acting on the contact layer 40 by the outer frame 50 is equalized in the axial direction, thereby increasing the total resistance.

<<Contact layer>>

As shown in FIG. 17(a), the contact layer 40 has a structure in which a number of string-like bodies 44, each having a circular cross section, are arranged along a virtual cylindrical surface (an example of a "virtual cylindrical surface") concentric with the cylinder 12 as a number of discrete bodies that are discretely arranged in the circumferential direction of the cylinder 12. As shown in FIG. 17(b) and FIG. 16, each string-like body 44 includes a core material 46 made mainly of metal, and a coating layer 42 (an example of a "surface layer") that covers the core material 46 and is made mainly of a soft material. The material that constitutes the coating layer 42 is an example of a "surface layer material".

<Contact layer structure>

As shown in FIG. 16, one example of each cord-like body 44 is a resin-coated wire rope. The resin-coated wire rope has a wire rope as the core material 46, a synthetic resin sleeve as the coating layer 42, and is configured as a wire rope whose surface is coated with synthetic resin.

Here, a "wire rope" is made by twisting together multiple strands (small ropes, small pieces) of multiple strands around a core (steel core, core rope). The material of the "strands" is metal, such as stainless steel, tungsten, or titanium alloy. The "core" is also called a fiber core or metal core. The material that makes up the "coating layer 42" is synthetic resin (PVC, nylon, polyethylene, etc.) (an example of a "soft material").

<Mechanical properties of the contact layer>

The coating layer 42 has flexibility (bendability). In addition, the core material 46 is allowed to slip between the multiple wires and between the multiple strands, and as a result, it has higher flexibility (ease of compressive deformation in the diameter direction (e.g., ease of crumbling or crushing of the strands), ease of bending in a direction crossing the length direction) than the core material 46 made of a single wire.

Furthermore, due to the elasticity of the respective materials, both the coating layer 42 and the core material 46 restore their cross-sectional shape (e.g., circular) and overall shape (straight line) when no load is applied (natural state) after unloading. Furthermore, the coating layer 42 has higher flexibility (ease of compressive deformation in the diameter direction, ease of bending in a direction intersecting the length direction) than the metallic coating layer 42.

To explain the difference between the coating layer 42 and the core material 46 in terms of mechanical properties, the coating layer 42 has a higher surface friction coefficient than the core material 46, while the core material 46 has a higher elastic recovery than the coating layer 42 (e.g., elastic recovery in the bending direction, elastic recovery in the compression direction, etc.).

In this embodiment, at least one end of each wire rope is terminal processed. Specifically, a sleeve or clip is crimped to the rope end as a prefabricated metal fitting. Because the prefabricated metal fitting is present at the end, when each wire rope is held on the inner surface of the outer frame 50 as shown in FIG. 1, each wire rope is prevented from falling under its own weight.

＜＜Outer frame＞＞

<Laminate capable of sliding motion>

As shown in Figures 10, 12, 13 and 14(a), the outer frame 50 has a small plate 54 as a low elastic deformation part that is easily elastically deformed in the radial direction in response to a radial force, and a large plate 56 as a high elastic deformation part that is not easily elastically deformed in the radial direction in response to a radial force, at different axial positions. Figure 14(a) is a plan view showing the small plate 54 shown in Figure 13 virtually superimposed on the large plate 56 shown in Figure 12 for comparison.

Specifically, the low elastic deformation portion is a small plate 54, which is a narrow plate having a width dimension W1, as shown in FIG. 14(a). In contrast, the high elastic deformation portion is a large plate 56, which is a wide plate having a width dimension W2 that is longer than the width dimension W1, as shown in the same figure.

In the small plate 54 shown in FIG. 14(a), multiple shallow grooves 60 are arranged along a true circular arc (an arc of a perfect circle) centered on the center of the chuck 20, as shown in FIG. 14(b).

Alternatively, as shown in FIG. 1B, a different arc shape from that of the small plate 54 may be used. One example of the different arc shape is a flattened arc having a radius R2 that is longer than the radius R1 of the true arc, as shown in the figure.

In this example, compared to the case where multiple shallow grooves 60 are arranged along a perfect circular arc with multiple corresponding string-like bodies 44, the radial distance of each string-like body 44 from the center of the column 12 is shorter, and the amount of radial outward deflection of the corresponding multiple small plates 54 increases accordingly.

As a result, in this example, even if the diameter of the column 12 is the same, a larger repulsive force acts from each small plate 54 to each string-like body 44, which increases the resistance acting in the radial direction (thickness direction) on the contact layer 40, and accordingly, the frictional force generated in the contact force also increases. In this way, the effect of amplifying the frictional force is obtained.

<Multiple vertical grooves on the outer frame>

As shown in FIG. 1, the outer frame 50 has multiple vertical grooves 58 (one example of a "groove") that contact the multiple string-like bodies 44 from behind and accommodate the string-like bodies 44. As shown in FIG. 15(b), each vertical groove 58 is a collection of multiple shallow grooves 60 and multiple deep grooves 62 that are lined up in a row.

As shown in FIG. 1D, in a compressed state in which each string-like body 44 is compressed by the columnar body 12, each string-like body 44 is crushed in the corresponding shallow groove 60 and flattened to extend in the circumferential direction. Similarly, although not shown, in a compressed state in which each string-like body 44 is compressed by the columnar body 12, each string-like body 44 is crushed in the corresponding deep groove 62 and flattened to extend in the circumferential direction, but to a lesser extent than in the shallow groove 60.

As shown in FIG. 1A, each of the longitudinal grooves 58 (shallow grooves 60 and deep grooves 62) has a cross-sectional shape that forms a partial circle that opens at the inner edge of the outer frame 50 (a cross-sectional shape that approximately complements the cross-sectional shape of the string-like body 44). The multiple longitudinal grooves 58 are formed by multiple shallow grooves 60 (an example of a "first partial groove") formed on each of the multiple small plates 54 and multiple deep grooves 62 (an example of a "second partial groove") formed on each of the multiple large plates 56, which are arranged in a row in the same phase in the vertical direction.

If the depth of the deep groove 62 is represented by "Q1" and the depth of the shallow groove 60 is represented by "Q2", the magnitude relationship between the two is expressed by the inequality Q1>Q2. Therefore, as shown in FIG. 1(a), the deep groove 62 is configured to have a cross-sectional shape that forms a partial circle larger than the cross-sectional shape of the shallow groove 60.

As shown in Figures 13 and 15(a)-(c), a number of shallow grooves 60 are arranged in a row on the inner edge of each small plate 54. Each shallow groove 60 is configured to have a cross-sectional shape that is generally semicircular. In contrast, as shown in Figures 12 and 15(a)-(c), a number of deep grooves 62 are arranged in a row on the inner edge of each large plate 56.

Here, Fig. 15(a) is an enlarged plan view showing one of the deep grooves 62 in the large plate 56 shown in Fig. 12 and one of the shallow grooves 60 in the small plate 54 shown in Fig. 13, which corresponds to the deep grooves 62 in the large plate 56 shown in Fig. 12, as viewed from directly above the stack shown in Fig. 9. Fig. 15(b) is a front view showing the multiple plates 54, 56 having the deep grooves 62 and shallow grooves 60. Fig. 15(c) is a side cross-sectional view showing the multiple plates 54, 56 having the deep grooves 62 and shallow grooves 60.

Each of the shallow grooves 60 and deep grooves 62 has a proximal portion 64, 66 closest to the outer surface of the column 12 and a distal portion 68, 70 furthest from the outer surface.

The proximal portion 64 of the shallow groove 60 is generally in the same relative position to the outer surface of the post 12 as the proximal portion 66 of the deep groove 62, but the distal portion 68 of the shallow groove 60 is closer to the outer surface of the post 12 than the distal portion 70 of the deep groove 62.

As a result, when each string-like body 44 is compressed by the column 12, the portion of each string-like body 44 that corresponds to the small plate 54 and the shallow groove 60 is compressed to a greater extent in the radial direction than the portion that corresponds to the large plate 56 and the deep groove 62, as shown in FIG. (d) as an example. As a result, the portion of each string-like body 44 that corresponds to the small plate 54 and the shallow groove 60 is flattened and crushed to a greater extent in the circumferential direction.

This generates an amplified resistance and therefore friction between each string-like body 44 and the cylinder 12, and also creates an enlarged contact area between each string-like body 44 and the cylinder 12.

＜＜Clamping mechanism＞＞

＜Basic configuration＞

The clamping mechanism 80 includes a circumferential clamping portion 82 (a first circumferential clamping portion 84 and a second circumferential clamping portion 86) that circumferentially connects and combines the multiple divided bodies 52, and an axial clamping portion 88 that axially connects and combines the multiple plates 54, 56 for each divided body 52.

＜Circumferential clamping section＞

As shown in FIG. 12, the circumferential clamping portion 82 is configured such that, for example, at clamping positions A and B, a long screw or shaft as a rod-shaped fastener clamps two adjacent divided bodies 52 in a circumferential or diagonal direction.

Figure 18(a) shows a plan view of the first circumferential clamping portion 84 used at multiple clamping positions A, and Figure 18(b) shows a side view.

The first circumferential clamping portion 84 includes a first long screw 140 that passes through clamping positions H1 and H2, and a second long screw 142 that passes through clamping position J. The first circumferential clamping portion 84 further includes two sets of an eyebolt 144, a nut 146, and a plate 148 that connect the long screws 140, 142 in the circumferential direction, arranged in parallel in the axial direction. The second long screw 142 at position J passes through the eye of the eyebolt 144. The plate 148 is disposed across the two first long screws 140, 140 that pass through positions H1 and H2, on the opposite side of the second long screw 142.

Figure 19(a) shows a plan view of the second circumferential clamping portion 86 used at multiple clamping positions B, and Figure 19(b) shows a side view.

The second circumferential clamping portion 86 includes a long screw 160 that passes through clamping position G and a first eyebolt 162 that passes through clamping position F, and further includes at least one set of a second eyebolt 164 and a nut 166 that connect the long screw 160 and the first eyebolt 162 in a direction oblique to the circumferential direction.

The bolt portion of the first eyebolt 162 passes through the through hole at position F and is fastened by the nut 168, and the bolt portion of the second eyebolt 164 passes through the eye portion of the same eyebolt 162. The long screw 160 at position G passes through the eye portion of the second eyebolt 164.

As shown in FIG. 12, in clamp position B, the second eyebolt 164 extends in a direction that intersects both the radial and circumferential directions. This second eyebolt 164 acts as the aforementioned diagonal member that extends in a direction that is inclined with respect to the tangential direction in clamp position B.

As a result of such geometry being provided to the second circumferential clamping portion 86, a radial force acts on the two adjacent segments 52 in addition to a circumferential force, thanks to the second circumferential clamping portion 86. This means that a part of the axial force of the second eyebolt 164, i.e., the clamping force of the segments 52, is converted into a radial force of the contact layer 40.

<Axial clamping section>

As shown in FIG. 10, the axial clamping portion 88 is configured to clamp each divided body 52, for example, at clamping positions D and E, with the rod-shaped fastener 130, which is a long screw or shaft, penetrating all of the plates 54, 56 or only the large plates 56.

Specifically, FIG. 10 shows how, as described above, in clamp position D, all plates 54, 56 are fastened by the long screws 130 that pass through them, and how, in clamp position E, multiple large plates 56 are fastened by the long screws 130 with a specified gap between them secured by the spacers 134.

<<How to remove the column>>

<Overview>

Figure 21 shows a process diagram of an example of a method for extracting the cylinder body 12 using the above-mentioned system 10.

According to this column extraction method, the column 12 is extracted from the base 14 in stages, as shown in Figures 5 and 7.

That is, this column extraction method includes a step of applying an axial force to the chuck 20, together with the column 12, as a quasi-static force rather than an impulsive force, by driving the jack 26 as shown in FIG. 5, in a direction that separates the column 12 from the foundation 14, thereby partially or completely extracting the column 12 from the foundation 14, and a step of applying an additional quasi-static axial force to the chuck 20, together with the column 12, as shown in FIG. 7, in a case where the column 12 cannot be extracted from the foundation 14 by using the jack 26 alone, in a direction that separates the column 12 from the foundation 14, by driving the hoist 30, thereby completely extracting the column 12 from the foundation 14.

1. First process: Equipment delivery and assembly

The multiple pieces of equipment required for the extraction work (such as the base unit 24 shown in Figures 3 and 4, the mounting jig 22 shown in Figure 3, the chuck 20 shown in the same figures, the jack 26 shown in Figure 5, the hoist 30 shown in Figure 7, the chain 120 shown in the same figure, and the scaffolding 32 shown in the same figure) are loaded in a disassembled state from their storage locations onto a transport vehicle such as a truck and transported to the destination site (such as a used parking lot where the equipment removal is desired).

When the equipment arrives at the site, it is assembled by workers.

2. Second step: Pulling out using jack 26

<Overview>

This process mainly involves driving the jack 26 to apply an axial force to the chuck 20 in a direction that moves it and the column 12 away from the base 14 as a quasi-static force (quasi-static load) rather than an impulsive force (impact load), thereby pulling the column 12 out of the base 14.

Here, a "quasi-static force (quasi-static load)" is defined as a dynamic load that does not include a static load, in that its magnitude changes over time, and does not include an impact load. Specifically, a "quasi-static force (quasi-static load)" is a load whose magnitude changes over time at a slower rate than an impact load, and whose magnitude transitions through a gradual increase phase, a gradual decrease phase, a holding phase, etc.

＜Preparation work＞

Prior to the extraction operation, the necessary equipment (base unit 24, mounting jig 22, chuck 20, jack 26, etc.) is assembled on-site.

Specifically, as shown in FIG. 2(a), in the preparation stage before extraction, the column body 12, the chuck 20, and the base part 14 are arranged integrally.

Specifically, in this preparation stage, as shown in FIG. 4, a hollow base unit 24 (an example of a "displacement prevention unit") is first installed to cover the foundation 14 in order to prevent the foundation 14 from lifting up as the pillar 12 rises. An example of the base unit 24 is shown in a perspective view in FIG. 5. In this example, the pillar 12 penetrates the center of the base unit 24.

Next, the hollow mounting jig 22 is installed on the top surface of the base unit 24 with the column 12 passing through its center.

Then, the chuck 20 is placed on the upper surface of the mounting jig 22 before its assembly is completed and in a state in which the column 12 is accessible from both diametric sides. In this state, the multiple segments 52 are clamped using the clamping mechanism 80 so that the chuck 20 grips the column 12. This completes the gripping operation of the column 12 by the chuck 20.

Then, multiple jacks 26 are placed on the upper surface of the base plate in opposing positions so as to sandwich the column 12 from both diametric sides. At this time, each jack 26 is in its maximum contraction position, and for convenience of installation work, a gap is usually provided between the upper end surface of the jack 26 and the lower surface of the chuck 20.

As shown by jack 26 (load position, jack position) C in the plan view of FIG. 12, each jack 26 locally contacts the lower surface of the chuck 20 at the upper end of its ram 100 at a position eccentric to the center of the column 12.

When the installation of each jack 26 is completed in this manner, the mounting jig 22 is removed from the column body 12 as shown in Figure 5. This completes preparations for the retraction work using the jacks 26.

＜Main work＞

The operator repeatedly swings the lever 116 of the jack 26. This increases the lifting force of the jack 26, and as shown in Figures 5 and 11, this lifting force acts on the chuck 20 from the jack 26 as a concentrated eccentric load.

The jacks 26 are arranged facing each other, one on each side, across the axis of the column body 12, and the two jacks 26 are operated by one or two workers so that their respective lifting forces rise in nearly synchronous with each other. The joint action of the jacks 26 applies an axial force to the column body 12 in a direction that pulls it out of the base 14. The opposing arrangement and synchronous operation of the multiple jacks 26 creates a tendency for the opposing bending moments caused by the eccentric loads of the jacks 26 to be offset in the column body 12.

Before the pull-out, there is a gap between the top surface of the ram 100 of the jack 26 and the bottom surface of the chuck 20. When the operator drives the jack 26, the lifting force increases until the gap disappears, as shown in the graph in FIG. 22, for example, until it overcomes the weight and frictional force of the ram 100. Eventually, the jack 26 and the chuck 20 come into contact at jack position C in FIG. 12.

Before being pulled out, the pillar 12 and the base 14 are integrated at their surfaces. Therefore, in order to pull out the pillar 12 from the base 14, it is necessary to apply a force to the pillar 12 that overcomes the adhesive force between them (e.g., adhesive force, joining force, etc.). This force is necessary to separate and peel the pillar 12 from the base 14. Furthermore, it is assumed that it is also necessary to apply a force to the pillar 12 that overcomes the maximum static friction coefficient between the pillar 12 and the base 14.

Here, the force required for extraction is, for example, a force that resists the column body 12 being pulled out of the base portion 14, i.e., a force that overcomes the pull-out resistance force (or pull-out strength). In this embodiment, due to the configuration of the system 10, the force required for extraction also includes a force that overcomes the sum of the weight of the column body 12 and the weight of the chuck 20.

Therefore, if the operator continues to drive the jack 26 after the jack 26 comes into contact with the chuck 20, the lifting force of the jack 26 increases, but until it reaches the pull-out resistance force, neither the chuck 20 nor the column 12 rises and remains stationary. In this phase, even if the operator repeatedly swings the lever 116 of the jack 26 to increase the lifting force of the jack 26, the ram 100 does not rise, and instead, it is presumed that the hydraulic fluid in the jack 26 is compressed.

Eventually, when the lifting force of the jack 26 overcomes the pull-out resistance, both the chuck 20 and the column 12 begin to rise, but at this point, the force required for the rise is the sum of the force to overcome the coefficient of kinetic friction between them and the weight of the column 12 and the weight of the chuck 20, so the lifting force of the jack 26 decreases. After that, both the chuck 20 and the column 12 rise by the amount that the worker drives the jack 26.

Eventually, the ram 100 of the jack 26 reaches its highest position. At this point, some of the column 12 remains in the foundation 14, and the column 12 is not completely pulled out of the foundation 14. This is because the lifting height of the jack 26 is lower than the initial embedment depth of the column 12 into the foundation 14.

3. Third step: Additional extraction step using hoist 30

<Overview>

In this process, when the column body 12 cannot be completely pulled out from the foundation 14 by using only the jack 26, as shown in FIG. 7, the worker operates the hoist 30 to quasi-statically apply an additional axial force to the chuck 20 in a direction that moves it and the column body 12 away from the foundation 14, thereby completely pulling out the column body 12 from the foundation 14.

＜Preparation work＞

As shown in FIG. 7, a worker sets up the first stage of scaffolding 32 in a predetermined position relative to the column body 12. A hoist 30 is suspended from the top plate of the scaffolding 32. A chain 120 hangs down from the hoist 30, and a hook 122 is attached to the end of the chain 120. The hook 122 is connected to an eye bolt 124 that serves as a connector for the chuck 20.

＜Main work＞

Then, the worker drives the hoist 30 to wind up the chain 120, thereby lifting the chuck 20 together with the column body 12. This causes the column body 12 to be further lifted from the base 14, and finally the column body 12 is completely pulled out from the base 14.

However, if the first level of scaffolding 32 is insufficient, a second level of scaffolding 32 is stacked as shown by the two-dot chain line in Figure 7, and the chuck 20 is again pulled up together with the column body 12 by the hoist 30.

As shown in FIG. 2(b), after the extraction, the column 12 and the chuck 20 are disposed integrally, while the column 12 is disposed separately above the base 14. After the extraction, a cylindrical hole (hereinafter referred to as the "trace hole") of approximately the same diameter as the column 12 appears in the base 14 as a trace of the column 12 having been extracted from there.

At this time, it is expected that no cracks will extend from the trace holes in the foundation part 14, or that even if cracks remain, they will be very small, and the foundation part 14 will not be destroyed.

4. Dismantling and removing equipment

When the column body 12 has been completely pulled out from the foundation 14 in this manner, the worker places the pulled-out column body 12 on the ground. The worker then dismantles the chuck 20, thereby removing it from the column body 12. The worker then removes the base unit 24, which is the equipment used in the pulling-out operation, from the foundation 14.

The workers then dismantle the other equipment. When the dismantling work has been completed for all the equipment, the workers load the equipment into the transport vehicle and return it to the storage location.

<<Test example>>

Here, we will explain the specific specifications of the column body 12, the chuck 20, and the jack 26 and hoist 30 as axial force applying devices, based on an example in which the inventors actually conducted tests.

<Column specifications>

Diameter: 114mm
Thickness: 2mm
Material: Steel Total length: 5.5m
Length above ground: 4m
Length underground: 1.5m

<Basic specifications>

Made of concrete

<Specifications of the string-like body>

Model number: PVC3-5-200-1M (JIS G 3525 1998) Manufactured by Nikko Steel Works, Ltd. Structure: "7-wire 6-ply central fiber core": Has 6 strands, each of which is made of 7 wires, and has a fiber core in the center of the multiple strands.
Core: Stranded wire Covering layer: PVC (soft vinyl)
Rope diameter (core diameter): 3 mm
Coating outer diameter (apparent diameter): 5 mm

<Jack specifications>

Allowable load (maximum lifting force): 4 tons Lowest position: 194 mm
Highest position: 372mm
Lift height: 178mm
Weight: 3.3 kg

In this test example, as in the previous embodiment, two jacks 26 were used in parallel for one column 12, so the total maximum lifting force was 8 tons, which is twice the maximum lifting force of one jack 26.

<Hoist specifications>

Rated load (maximum lifting force): 0.3 ton Lifting height: 2.5 m

In this test example, as in the previous embodiment, one hoist 30 was used for each column 12, so the final maximum lifting force remained at 0.3 tons.

＜Test results＞

The inventors have prototyped this system 10 using equipment with these specifications, and performed experimental extraction work on-site on a column body 12 and a foundation 14 with the above specifications.

As a result, the inventor recognized that, as described above, during the extraction process using the jack 26, the lifting force of the jack 26 showed the time transition illustrated in FIG. 22. Furthermore, the inventor confirmed that after extraction, there were no traces on the portion of the column 12 where the chuck 20 was attached, and, as described above, there were no harmful traces on the base portion 14.

The inventor therefore recognized that it would have been possible to reuse the removed column body 12 in another location without substantial repair. Furthermore, the inventor recognized that it would have been possible to avoid removing the foundation portion 14 from the soil if the foundation portion 14 had been backfilled at the site without excavating the soil.

Furthermore, the inventors confirmed through this test that the extraction work could be performed with low vibration and low noise, that the labor required for the work (man-hours and construction time) could be reduced (the work time was, for example, about 3 hours), and that the work costs could be reduced.

<<Other benefits of this embodiment>>

This embodiment provides the following advantages:

Although the cylinder 12 is a rigid body, the contact between the cylinder 12 and the contact layer 40 appears as rigid-soft contact, which improves the fit of the surface of the contact layer 40 to the surface of the cylinder 12 more easily than contact between rigid bodies.

<<Various variations on this embodiment>>

Although several exemplary embodiments of the present invention have been described above, the present invention can be embodied in other forms.

<Variations in the shape of the part gripped by the chuck>

For example, in this embodiment, the column 12 is configured as a longitudinal member having a straight portion, and the chuck 20 is configured to be attached to the straight portion.

In contrast, if the longitudinal member has a curved portion, the chuck 20 may be configured to be attached to the curved portion. Also, if the longitudinal member has an angled portion, the chuck 20 may be configured to be attached to the angled portion.

According to this embodiment, as described above, when the longitudinal member is rigid, the contact between the longitudinal member and the chuck 20 is a contact between a rigid body and a soft body, and even when the chuck 20 has a non-simple shape that is not a straight line, such as a curved or angled portion, it is easy to fit the shape.

<Variations in the cross-sectional shape of the column>

In addition, in this embodiment, the column 12 is a longitudinal member having a hollow structure and a closed cross-sectional shape, but the present invention may also be implemented in a manner in which a longitudinal member having a hollow structure and an open cross-sectional shape (e.g., a pipe with a vertical slit) is gripped by the chuck 20.

In addition, in this embodiment, the column 12 is a longitudinal member having a hollow structure and an outer peripheral surface that is continuous in the circumferential direction, but the present invention may also be implemented in a manner in which a longitudinal member having a hollow structure and an outer peripheral surface that has discontinuous portions in the circumferential direction is gripped by the chuck 20.

The present invention may also be implemented in a manner in which a longitudinal member having a solid structure and an outer peripheral surface that is continuous in the circumferential direction or has an outer peripheral surface that has discontinuous portions in the circumferential direction is gripped by the chuck 20.

<Variations in column installation method>

As shown in FIG. 8, there are at least three exemplary installation methods for the column body 12 that can be extracted (removed) according to the present invention.

Specifically, FIG. 1(a) shows a first installation method in which the column body 12 is embedded and fixed in a foundation part 14 that is buried in the ground. In this embodiment, the column body 12 is configured as a longitudinal member that is installed according to the first installation method. In this case, as described above, the column body 12 as a longitudinal member is pulled out from the foundation part 14, leaving the foundation part 14 in the ground.

Figure 1B also shows a second installation method in which the column 12 is buried and fixed directly into the ground. The present invention may also be implemented in a form in which the column 12 is installed according to the second installation method, and the chuck 20 is attached to the longitudinal member. In this case, the column 12 as the longitudinal member is pulled out of the soil by itself.

Figure (c) also shows a third installation method in which the column 12 is embedded and fixed in a foundation 14 buried in the ground, with the bottom end of the column 12 joined to a widened portion 16 (such as a member having a shape that protrudes from the cross-sectional shape of the main body of the column 12) in a position exposed from the foundation 14.

The present invention may also be practiced in a manner in which the chuck 20 is attached to a longitudinal member installed according to the third installation method. In this case, the column body 12 (with the expanded bottom portion 16 attached) as the longitudinal member is pulled out of the soil together with the base portion 14.

<Modifications of the contact layer structure>

In this embodiment, as described above, the contact layer 40 has a structure in which a plurality of cord-like bodies 44, each having a circular cross section, are arranged along an imaginary cylindrical surface concentric with the cylinder 12 as a plurality of discrete bodies that are discretely arranged in the circumferential direction of the cylinder 12, as shown in Figures 17(a) and (b).

Alternatively, the contact layer 40 may be configured as shown in (c) and (d) of the same figure, in which, for example, a plurality of cord-like bodies 44, each having an oval cross section, are arranged in a discrete manner around the cylinder 12 along an imaginary cylindrical surface concentric with the cylinder 12 as a plurality of discrete bodies that are discretely arranged around the cylinder 12.

As another example, the contact layer 40 may be implemented in the present invention in a form in which a single cylindrical body (such as a sleeve) that is continuous in the circumferential direction of the cylinder 12 extends axially along an imaginary cylindrical surface that is concentric with the cylinder 12, as shown in FIG. 1(e).

<Modification of the string-like body arrangement method>

In this embodiment, multiple string-like bodies 44 are arranged so that they extend in parallel to the axis of the cylinder 12 along an imaginary cylindrical surface that is substantially concentric with the cylinder 12.

In contrast to this, the present invention may be implemented in a manner in which the string-like bodies 44 are arranged so as to extend in parallel in a spiral shape around the axis of the imaginary cylindrical surface. This arrangement makes it easy to reduce the number of string-like bodies 44 required to achieve the same contact area between the string-like bodies 44 and the column body 12.

<Variations in the cross-sectional shape of the column>

In this embodiment, the column 12 is a columnar body (solid), a cylindrical body, or a round pipe (hollow), but instead, for example, as shown in FIG. 20, the column 12 may be configured as a square columnar body (solid), a square tube, or a square pipe (hollow).

Specifically, FIG. 1A is a plan view showing a chuck 20 suitable for another example of the columnar body 12, which is a square column or a square tube, and FIG. 1B is a plan view showing an enlarged view of the contact layer 40 shown in FIG. 1A. In this case, a "virtual square tube surface" is used as the "virtual tube surface."

<Modification of the drive system for lifting the chuck>

In this embodiment, in the initial stage of the extraction process of the column body 12, when the resistance to the extraction of the column body 12 is large, a jack 26 (high output, low lift or high output, short stroke) is used as the first driving source, and the chuck 20 is raised by pushing up the chuck 20 with the jack 26.

Then, in the subsequent stage when the pulling resistance force decreases, a hoist 30 (low output, high lift or low output, long stroke) is used as the second driving source instead of the jack 26, and the chuck 20 is raised by pulling up the chuck 20 with the hoist 30.

That is, in this embodiment,
(1) The allowable load and maximum stroke of the drive source differ depending on the type of drive source. Specifically, for example, the jack 26 is more advantageous than the hoist 30 in terms of the size of the allowable load (maximum output, maximum lifting force, etc.), but is less advantageous than the hoist 30 in terms of the length of the maximum stroke (lifting height, etc.) (these two types of drive sources have a complementary relationship in terms of performance, compensating for each other's shortcomings);
(2) In consideration of the fact that the magnitude of the load and the length of the lift required for extraction differ depending on the stage of the extraction process, specifically, for example, that in the initial stage, a large load is required but a short lift is acceptable, whereas in subsequent stages, a long lift is required but a small load is acceptable, multiple types of drive sources are used according to the magnitude of the required load and the length of the maximum stroke, i.e., according to the stage of the extraction process.

In contrast, if one type of drive source is used that can achieve the maximum load and maximum stroke required at each stage of the extraction process (e.g., the initial stage and the subsequent stage) throughout all stages of the extraction process, the retraction of the column body 12 can be completed using only one type of drive source throughout all stages of the extraction process.

For example, the present invention may be implemented in such a way that a high-performance lifting machine such as a hoist 30 or a crane is used as the driving source, and the chuck 20 is lifted throughout the entire process using the driving source, thereby allowing the column 12 to be pulled out without switching driving sources.

In this embodiment, in order to attach the chuck 20 to the column 12 prior to the extraction of the column 12, the worker brings the multiple segments 52 of the chuck 20 close to the column 12 in a horizontal plane. Therefore, in order to extract the column 12 using the chuck 20, a space or gap is required for each segment 52 to move horizontally.

Therefore, at a removal site where there are obstacles (walls, nearby buildings, etc.) near the column body 12, such as those shown in FIG. 23, it is difficult or impossible for the worker to attach the chuck 20 to the column body 12.

<Another embodiment>

To solve this problem, the chuck 20 may be configured as, for example, an asymmetric hinge assembly chuck 170 as shown in FIG. 24.

This chuck 170 has an asymmetric shape in which, for example, when viewed from above, the column 12 is narrow or small at the back where the gap is narrow because the column 12 is closer to the obstacle, and is wide or large at the front where the gap is wide because the column 12 is farther from the obstacle.

Furthermore, this chuck 170 is configured to include, for example, a narrow base end portion 172 located at the rear side, a pair of arms 174, 174 connected to the narrow base end portion 172 by a hinge 173, which are capable of clamping the column body 12 from both sides in the diametric direction, and a slide portion 176 between the arms 174, 174 that is slidable relative to the arms 174, 174.

Furthermore, this chuck 170 has a plurality of partial cylindrical surfaces formed by dividing one circumferential surface, for example, on the inner surface of the base end portion 172, the inner surface of each of the pair of arm portions 174, 174, and the inner surface of the slide portion 176. A contact layer 178 similar to the contact layer 40 described above is formed on these partial cylindrical surfaces.

Furthermore, in this example, the worker positions the chuck 170 in the deployed state so that it passes through the back side of the column body 12.

Then, the operator brings the pair of arms 174, 174 closer to each other to compress the cylinder 12 in one diameter direction U, and brings the base end 172 and the slide portion 176 closer to each other to compress the cylinder 12 in another diameter direction V perpendicular to the diameter direction U, thereby elastically and non-invasively pressing the chuck 170 against the cylinder 12 all around.

In this example, the base end 172 and the pair of arms 174, 174 can be interpreted as constituting a lever mechanism in which a pair of levers are connected to the base end so as to be swingable on a plane (e.g., a horizontal plane), and which supports the contact layer 178 from behind.

It should be noted that, although it has been noted that in some of the embodiments exemplified above, high friction and non-invasive contact are compatible in the chuck, if reuse of the extracted cylinder 12 is not required, non-invasive contact does not have to be achieved in the chuck.

Although several exemplary embodiments of the present invention have been described in detail above with reference to the drawings, these are merely examples, and the present invention can be embodied in other forms that incorporate various modifications and improvements based on the knowledge of those skilled in the art, including the forms described in the "Summary of the Invention" section above.

Claims (11)

A chuck that is detachably attached to an existing longitudinal member in order to pull the longitudinal member out of a support portion or a foundation portion embedded in the support portion, or to pull the longitudinal member out of the support portion together with the foundation portion,
a cylindrical contact layer that surrounds the outer peripheral surface of the longitudinal member locally in the axial direction and entirely or partially in the circumferential direction, the contact layer having elasticity at least in the radial direction and a soft material at least in a surface layer, the inner peripheral surface of the contact layer contacting the outer peripheral surface of the longitudinal member;
an outer frame that holds the contact layer in a supporting manner from behind, and non-invasively grips the longitudinal member by compressing the contact layer on its inner surface against the outer circumferential surface of the longitudinal member within its elastic range;
The contact layer is a chuck for extracting a longitudinal member, which is constituted by an arrangement of a plurality of string-like bodies discretely arranged in the circumferential direction of the longitudinal member, each of which extends parallel or obliquely to the axis of the longitudinal member . 2. The chuck for extracting a longitudinal member according to claim 1, wherein each of the plurality of string-like bodies is in compressed state brought into contact with the inner surface of the outer frame and the outer peripheral surface of the longitudinal member on both sides thereof in the compressed state. 2. The chuck for extracting a longitudinal member according to claim 1, wherein the plurality of string-like bodies are arranged so as to extend parallel to an axis of the longitudinal member or spirally around the axis of the longitudinal member along an imaginary cylindrical surface that is substantially concentric with the longitudinal member in the compressed state . 2. The chuck for extracting a longitudinal member according to claim 1 , wherein each of said string-like bodies includes a core material mainly made of metal and a coating layer covering said core material, said coating layer being mainly made of a soft material. The chuck for extracting a longitudinal member according to claim 1, wherein the soft material includes an elastic body, a synthetic resin, an elastomer, or a rubber. Each of the cord-like bodies is made of a resin-coated wire rope in which a wire rope is coated with a synthetic resin,
2. The longitudinal member extraction chuck of claim 1 , wherein the resin-coated wire rope extends generally linearly in a natural state when not attached to the chuck. the coating layer has a higher surface friction coefficient than the core material;
5. The chuck for extracting a longitudinal member according to claim 4, wherein said core material has a higher elastic recovery than said covering layer. 2. The chuck for extracting a longitudinal member according to claim 1 , wherein the outer frame includes a plurality of grooves on its inner surface for partially receiving the plurality of string-like bodies behind them. The chuck for extracting a longitudinal member according to claim 8, wherein at least some of the grooves include a depth change portion whose depth changes in the longitudinal direction. A method for extracting an existing longitudinal member from a support or a foundation embedded in the support, or from the support together with the foundation, comprising the steps of:
a gripping step of gripping the longitudinal member by clamping the longitudinal member within its elastic range using a chuck according to any one of claims 1 to 9;
and applying an axial force to the chuck in a direction that moves the chuck, together with the longitudinal member, away from the support portion or the base portion. The method for extracting a longitudinal member according to claim 10, wherein the gripping step grips the longitudinal member non-invasively.

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