Chuck for drawing longitudinal member

Abstract

To provide a technique capable of gripping an existing longitudinal member, and simply drawing the longitudinal member from an installation place thereof with low nose and low vibration.SOLUTION: A chuck 20 which is detachably mounted on an existing longitudinal member 10 so as to draw the longitudinal member from an installation place thereof includes: a cord body arrangement 40 where multiple cord bodies 44 each having elasticity extend along a virtual cylindrical surface coaxial with the longitudinal member and are discretely arrayed in a circumferential direction of the longitudinal member; and an outer frame 50 which holds the cord body arrangement in a state of supporting an outside surface thereof from outside, is brought into contact with the outside surface of the cord body arrangement on an inner surface thereof, thereby brings the inside surface of the cord body arrangement into contact with the outer peripheral surface of the longitudinal member in a compressive state in an elastic region, and thereby grips the longitudinal member. The outer frame includes a plurality of grooves for partially storing the cord bodies, on the inner surface of itself. At least a part of the grooves includes a depth changing part for changing the depth in a length direction thereof.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a technique for extracting an existing longitudinal member from its installation location. [Background technology]

[0002] A longitudinal member (e.g., a pillar, a pile, a beam, etc.) is fixed to a support (e.g., the ground, a wall) as one member constituting a structure, or a longitudinal member is fixed to a support as a separate member from the structure and for the purpose of supporting the structure at a position above a reference plane (e.g., the ground, a wall surface). In the latter case, the structure is supported by the longitudinal member fixed to the support.

[0003] Here, the "longitudinal member" may be classified by cross-sectional structure, for example, hollow or solid, by material, for example, metal or 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, the "longitudinal member" may be an already buried body, or may be a prefabricated member or a member constructed on-site.

[0004] Moreover, the "supporting part" is, for example, soil or a wall. When the "supporting part" is soil, the "longitudinal member" is, for example, a pillar or a pile. When the "supporting part" is a wall, the "longitudinal member" is, for example, a beam.

[0005] To explain these structural materials in more detail using a parking lot as an example, an example of a "longitudinal member" would be a power pole (an example of a "pillar") that supports electrical components such as lights at a position elevated above the ground, or one or more pillars (an example of a "pillar") that support a sign displaying fare information, etc. at a position elevated above the ground.

[0006] The lower ends of the 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 the structural members are buried and fixed to the concrete foundation.

[0007] There are two methods for fixing longitudinal members to the ground: a driving method and an embedding method.

[0008] The driving-in method is a method in which prefabricated longitudinal members (such as prefabricated piles or columns) are driven into the ground by the striking force of a hammer, without having to dig pilot holes in the soil beforehand.

[0009] In contrast, the embedding method is a method in which a pilot hole is made by excavating the ground to a specified depth, and a prefabricated longitudinal member (such as a prefabricated pile or column) is inserted into the pilot hole. One such embedding method is called the root wrapping method (see, for example, Patent Document 1). This root wrapping method is a method in which, for example, an enlarged bulb made of concrete 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 may be created without using reinforcing bars.

[0010] According to this method, a pilot hole is excavated in the ground, crushed stone is poured into the bottom of the hole, and then the crushed stone is 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.

[0011] For example, as disclosed in the above-mentioned Patent Document 1, a longitudinal member 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 member be removed from the installation location and the installation location be returned to a vacant lot.

[0012] 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 foundation. In this case, it may be necessary to spend a lot of effort (man-hours, construction time, etc.) and cost (labor costs, equipment costs, etc.) to remove the longitudinal members.

[0013] Such circumstances exist, for example, in the field of parking lot management.

[0014] Specifically, when land owned by a landowner is likely to be sold or is scheduled 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.).

[0015] In this case, if the landowner decides to use his / her land for another purpose or to sell it, he / she will request the parking lot operator to return his / her land to vacant land. 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.

[0016] 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 as low a cost as possible.

[0017] Incidentally, 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.

[0018] However, the term includes the lexical phrase "to pull out," which means that an object is removed or separated from an object. Therefore, when the term "to pull out" is used, it can be interpreted in a narrow sense so that it is essential that the object is removed from the object.

[0019] 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.

[0020] In contrast, the term "completely pull out" is sometimes used when it is necessary to clearly distinguish the event in which an object is ultimately detached from an object due to the action of pulling the object within the object in a direction that causes the object to be detached from the object from other events.

[0021] Moreover, 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, because whether the axial force applied to the longitudinal member is a pushing force or a pulling force, the longitudinal member will be pulled out of the support or base.

[0022] Prior art techniques for pulling and removing a longitudinal member from its installation site are disclosed in Patent Documents 1 to 4.

[0023] Patent Document 1 discloses a technique for extracting a pillar (an example of a "longitudinal member") together with its foundation in which it is embedded, from the soil.

[0024] Specifically, according to this technique, first, multiple metal tips are welded to the outer periphery of the upper end of the column 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 by a crane or other heavy machinery, and the column is pulled out of the ground together with the surrounding foundation.

[0025] Patent Document 2 discloses the following methods for extracting steel materials (an example of a "longitudinal member") from the ground: (a) a method in which the steel materials are directly extracted by a hydraulic or vibratory extractor; (b) a method in which various lubricating materials are placed around the steel materials in advance as an edge separator, thereby weakening the extraction strength (the resistance when the steel materials are extracted), and then the steel materials are extracted under these conditions; and (c) a method in which a fracturing agent is used.

[0026] Patent Document 3 discloses a method of inserting an intermediate material between a steel material (an example of a "longitudinal member") and a cement-based hardened material in order to reduce the pull-out resistance of the steel material during installation.

[0027] Specifically, according to this technique, before a steel material is inserted into an unhardened cementitious hardened material, a resin coating that is degraded by the alkaline components in the cementitious hardened material is applied to the portion of the steel material that will come into contact with the cementitious hardened material, whereby the resin coating is degraded by the alkaline components, making it easier to pull out the steel material.

[0028] Patent Document 4 discloses a method for removing an already buried pile (an example of a "longitudinal member"). Specifically, this is a method in which the surrounding area of ​​the pile is hollowed out together with the ground, the edge between the ground and the pile is cut, and the pile is pulled out of the soil with the soil still attached.

[0029] Further, prior art chucks that are attached to a longitudinal member in order to pull the longitudinal member out of its installation location are disclosed in Patent Documents 5 to 7. exist.

[0030] Patent Document 5 discloses a chuck that holds a stake (an example of a "longitudinal member") by clamping it between a pair of jaws from both diametrical sides.

[0031] The pair of jaws are arranged at different positions in the axial direction so as to sandwich the pile in a cross-sectional manner in a side view when the jaws are in a holding state in which the pile is held by the pair of jaws. Furthermore, in the holding state, the chuck is pulled up by a hoist together with the pile, thereby pulling the pile out of the ground or the like.

[0032] 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 peripheral surface of the pillar material (an example of a "longitudinal member") using the wedge principle.

[0033] 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 peripheral surface of the reinforcing bar (an example of a "longitudinal member") using the wedge principle. [Prior art documents] [Patent documents]

[0034] [Patent Document 1] JP 2014-001542 A [Patent Document 2] Japanese Patent Application Publication No. 2-176014 [Patent Document 3] Japanese Patent Application Publication No. 59-078809 [Patent Document 4] JP 2011-196114 A [Patent Document 5] JP 2002-038482 A [Patent Document 6] JP 2002-180466 A [Patent Document 7] JP 2011-107000 A Summary of the Invention [Problem to be solved by the invention]

[0035] 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 problem.

[0036] 1. It is easy to reduce vibration and noise caused by the removal of longitudinal members.

[0037] Reducing the vibrations and noise associated with the removal of longitudinal members has the advantage that the removal work can be carried out without disturbing neighboring residents, and that the removal work can be carried out at night when it is quieter than during the day.

[0038] 2. To facilitate removal of longitudinal members using simple work and equipment.

[0039] If the work and equipment required for removing the longitudinal members can be simplified, the workload of workers can be reduced and the work costs can be reduced.

[0040] 3. To reduce traces of the removal work remaining on the removed longitudinal members.

[0041] If traces of the removal process remaining on the removed longitudinal members can be reduced, the removed longitudinal members can be reused to the extent that it does not cause any problems, which has the effect of facilitating the effective use of resources and reduction in equipment costs.

[0042] In light of the above-described circumstances, the present invention provides a method for non-invasively replacing an existing longitudinal member. or invasively The objective of this study was to provide technology that would enable the device to be grasped and easily removed from its installation location with little noise and vibration. [Means for solving the problem]

[0043] In order to solve the problem, according to one aspect of the present invention, an existing longitudinal member is Its locationa chuck removably attached to the longitudinal member for withdrawal from the longitudinal member, a string-like body array including a plurality of elastic string-like bodies extending parallel to an axis of the longitudinal member or spirally around the axis of the longitudinal member along an imaginary cylindrical surface coaxial with the longitudinal member, and discretely arranged in a circumferential direction of the longitudinal member; an outer frame that holds the outer surface of the string array in a state of supporting it from the outside, and that contacts the outer surface of the string array with its inner surface, thereby gripping the longitudinal member by bringing the inner surface of the string array into contact with the outer peripheral surface of the longitudinal member in a compressed state within its elastic range; Including, the outer frame includes, on its inner surface, a plurality of grooves that partially receive the plurality of strings on their respective outer surfaces; At least some of the grooves include a depth change portion that changes depth along the length of the grooves. A longitudinal member extraction chuck is provided.

[0044] 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.

[0045] 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 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; An outer frame that supports the contact layer from behind; Including, 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.

[0046] 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, comprising: The chuck; a first unit that engages with the chuck and quasi-statically applies an axial force to the chuck in a direction that moves the chuck and the longitudinal member away from the support portion or the base portion; A longitudinal member extraction system is provided that includes:

[0047] According to a fourth aspect of the present invention, there is provided a method for extracting an existing longitudinal member from a support part or a foundation part embedded in the support part, or for extracting an existing longitudinal member from the support part together with the foundation part, the method comprising the steps of: atraumatically gripping the longitudinal member by clamping the longitudinal member within its elastic range with the chuck; 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. A method for extracting a longitudinal member is provided, comprising:

[0048] 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.

[0049] 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 in which a pair of levers are connected to a base end so as to be swingable on one plane, and at least one of the base end and the pair of levers supports the contact layer from behind on the inner surface of each of the base end and the pair of levers. Including, 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.

[0050] The present invention provides the following embodiments. Each embodiment is divided into clauses, each clause is numbered, and other clause numbers 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 embodiments. In other words, it should be construed that technical features that are not described in the following embodiments but are described in this specification may be appropriately extracted and employed as technical features of the present invention.

[0051] Furthermore, describing each section in a form that refers to the number of other sections does not necessarily mean that the technical features described in each section are prevented from being separated and made independent from the technical features described in other sections, and it should be interpreted that the technical features described in each section can be made independent as appropriate depending on their nature.

[0052] (1) A chuck that is detachably attached to an existing longitudinal member in order to pull the longitudinal member out of a support or a foundation embedded in the support, or to pull the longitudinal member out of the support together with the foundation, 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 which is elastic at least in the radial direction and has a soft material at least on its surface, and which completely or partially surrounds the outer circumferential surface of the longitudinal member.

[0053] (2) A chuck that is detachably attached to a longitudinal member in order to quasi-statically apply at least an axial force, among 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, 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 supports the contact layer from behind; Including, The contact layer non-invasively grips the longitudinal member by clamping the longitudinal member within its elastic range.

[0054] (3) A chuck for extracting a longitudinal member as described in (2), wherein 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.

[0055] (4) A chuck for extracting a longitudinal member according to any one of (1) to (3), wherein the contact layer contains a soft material as a surface layer material thereof.

[0056] (5) The chuck for extracting a longitudinal member according to the above (4), wherein the soft material includes an elastic body, a synthetic resin, an elastomer, or a rubber.

[0057] (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 contact layer has a higher bending deformation characteristic than when the contact layer is constructed as a single piece of metal. The chuck for extracting a long member according to any one of (1) to (5) above, which employs at least one of the above.

[0058] (7) A chuck for extracting a longitudinal member according to claim (6), wherein the contact layer includes, as a surface layer material, a soft material having higher compressive deformation characteristics than when the contact layer is formed as a single metal part.

[0059] (8) A chuck for extracting a long member as described in (2) or (3), wherein 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, the low elastic deformation portion being located at a position supporting the contact layer from behind and at a different axial position from each other.

[0060] (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, the first and second partial support surfaces each 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.

[0061] (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; When a load acting from the outside on the outer frame to pull out the longitudinal member is an eccentric load acting in a direction of a straight line offset from an axis of the longitudinal member, the chuck further includes a second force conversion mechanism that converts a part of the eccentric load into a radial force and applies the radial force to the contact layer. The chuck for extracting a long member according to claim 2 or 3, which employs at least one of the above.

[0062] (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.

[0063] (12) The chuck for extracting a longitudinal member according to claim (11), wherein the plurality of divided bodies are four divided bodies obtained by dividing the outer frame at substantially equal angles.

[0064] (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.

[0065] (14) A chuck for extracting a longitudinal member as described in (2) or (3) above, 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 a plurality of plates extending in a direction transverse to the longitudinal member, stacked in the axial direction of the longitudinal member while allowing the individual plates to slide and tilt.

[0066] (15) A chuck for extracting a longitudinal member as described in any one of (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.

[0067] (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.

[0068] (17) A chuck for extracting a longitudinal member as described in paragraph (16), wherein each of the string-like bodies includes a core material mainly made of metal and a coating layer covering the core material, the coating layer being mainly made of a soft material.

[0069] (18) The chuck for extracting a longitudinal member according to the above (17), wherein the soft material includes an elastic body, a synthetic resin, an elastomer, or a rubber.

[0070] (19) Each cord-like body 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.

[0071] (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.

[0072] (21) A chuck for extracting a longitudinal member according to any one of (16) to (20), wherein the contact layer includes a plurality of grooves on its outer surface for partially accommodating the plurality of cord-like bodies behind them.

[0073] (22) The chuck for extracting a longitudinal member according to (21), wherein at least a portion of the plurality of grooves includes a depth changing portion whose depth changes in the longitudinal direction.

[0074] (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, the low elastic deformation portion being located 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 and deep grooves having 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.

[0075] (24) A chuck for extracting a longitudinal member according to any one of (1) to (23), wherein the longitudinal member is hollow or solid.

[0076] (25) A chuck for extracting a longitudinal member according to any one of (1) to (24), wherein the longitudinal member is made of metal or concrete.

[0077] (26) A chuck for extracting a longitudinal member according to any one of (1) to (25), wherein the longitudinal member is a rod, a shaft, a tube or a cylinder.

[0078] (27) A chuck for extracting a longitudinal member according to any one of (1) to (26), wherein the longitudinal member is a pillar, a pile, a beam, or a reinforcing bar.

[0079] (28) The chuck for extracting a longitudinal member according to any one of (1) to (27), wherein the support portion is soil or a wall.

[0080] (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), a first unit that engages with the chuck and quasi-statically applies an axial force to the chuck in a direction that moves the chuck and the longitudinal member away from the support portion or the base portion; A longitudinal member extraction system comprising:

[0081] (30) Furthermore, A longitudinal member extraction system as described in item (29), which includes a second unit that engages with the chuck and quasi-statically applies an additional axial force to the chuck in a direction that causes the chuck and the longitudinal member to be additionally moved 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.

[0082] (31) The longitudinal member is embedded in the foundation, 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.

[0083] (32) A method for extracting a longitudinal member from the support or the base using the longitudinal member extraction system according to (29), comprising the steps of: 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; quasi-statically applying an axial force to the chuck in a direction to move the chuck together with the elongate member away from the support portion or the base portion by driving the first unit; A method for extracting a longitudinal member comprising the steps of:

[0084] (33) A method for extracting a longitudinal member from the support or the base using the longitudinal member extraction system according to (30), comprising the steps of: 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; a step of quasi-statically applying an axial force to the chuck in a direction to move the chuck together with the elongate member away from the support portion or the base portion by driving the second unit; A method for extracting a longitudinal member comprising the steps of:

[0085] (34) The 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.

[0086] (35) A chuck for extracting a longitudinal member as described in (4) or (5), in which, when the longitudinal member is a rigid body, contact between the longitudinal member and the contact layer appears as rigid-soft body contact, and the rigid-soft body contact improves the ease of fitting of the surface of the contact layer to the surface of the longitudinal member compared to contact between rigid bodies.

[0087] (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, so that the chuck can be attached to the straight portion, the curved portion, or the angle portion, when the longitudinal member has an angle portion, of the longitudinal member.

[0088] (37) A chuck for extracting a longitudinal member according to any one of (1) to (28), wherein the longitudinal member has a hollow structure and is configured to have a closed or open cross-sectional shape.

[0089] (38) A chuck for extracting a longitudinal member according to any one of items (1) to (28), wherein 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. [Brief description of the drawings]

[0090] [Figure 1] FIG. 1 is an exploded perspective view of a cylinder extraction system according to an exemplary embodiment of the present invention. [Diagram 2] 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. [Diagram 3] 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. [Figure 4] FIG. 4 is a perspective view of the base unit shown in FIG. [Diagram 5] FIG. 5 is a side view for explaining a step of installing a jack between the chuck and the base unit at a stage before extraction. [Figure 6] FIG. 6 is an enlarged side view of the jack shown in FIG. [Figure 7] FIG. 7 is a side view for explaining an additional pulling-out operation by a hoist as a second-stage pulling-out operation after the pulling-out operation by a jack as a first-stage pulling-out operation is completed. [Figure 8]Figure 8 is a side view illustrating three installation methods of the pillar body according to the embodiment shown in Figure 1. Specifically, Figure 8(a) shows a first installation method in which the pillar body is buried and fixed in a foundation buried in the ground, Figure 8(b) shows a second installation method in which the pillar body is buried and fixed directly in the ground, and Figure 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 buried in the ground in a position where the expanded bottom portion is exposed from the foundation. [Figure 9] FIG. 9 is a perspective view showing an enlarged representative one of the divided bodies shown in FIG. [Figure 10] FIG. 10 is a side cross-sectional view showing the division body shown in FIG. [Figure 11] FIG. 11(a) 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. 11(b) 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. [Figure 12] 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. [Figure 13] 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 three other divided bodies assembled thereto. [Figure 14] 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]Figure 15(a) is an enlarged plan view showing one of the deep grooves in the large plate shown in Figure 12 and one of the 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; (b) is a front view showing multiple plates having these deep grooves and shallow grooves; (c) is a side cross-sectional view showing multiple plates having these deep grooves and shallow grooves; and (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. [Figure 16] FIG. 16 is an enlarged perspective view of the string-like body shown in FIG. [Figure 17] 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 a virtual 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 a virtual 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 a virtual cylindrical surface concentric with the cylinder. [Figure 18] FIG. 18(a) is a plan view showing a first circumferential clamp portion used at a plurality of clamp positions A in FIG. 12 in the clamp mechanism shown in FIG. 1, and FIG. 18(b) is a side view. [Figure 19] FIG. 19(a) is a plan view showing a second circumferential clamp portion used at a plurality of clamp positions B in FIG. 12 in the clamp mechanism shown in FIG. 1, and FIG. 19(b) is a side view. [Figure 20] 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). [Figure 21] 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. [Figure 22] 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 the cylinder body pulling-out method shown in FIG. 21 is carried out. [Diagram 23] 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. [Figure 24] 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. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0091] Hereinafter, some of more specific exemplary embodiments of the present invention will be described in detail with reference to the drawings.

[0092] FIG. 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.

[0093] <<System Use>>

[0094] 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 site.

[0095] Specifically, as shown in the same figure and Figure 2, this system 10 is used to pull out and remove an existing pillar 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.

[0096] <<Basic system configuration>>

[0097] As shown in Figures 1 and 3 to 7, this system 10 includes a chuck 20 that grips the column body 12 non-invasively and in a full-circumference elastic fastening manner, 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.

[0098] The system 10 further includes a hoist 30 that applies additional axial force to the column body 12 via the chuck 20 to pull the column body 12 out of the base 14, and a multi-tiered stacking scaffolding 32 on which the hoist 30 is installed, for example, in a suspended state.

[0099] In this system 10, as shown in Figs. 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.

[0100] <<Multiple objectives achieved by the system>>

[0101] 1. Making the extraction process non-destructive and reducing vibration and noise

[0102] In this embodiment, the column body 12 is pulled out from the foundation 14 without using heavy machinery such as a small crane for the pulling out work, and without the need to destroy the foundation 14 using a vibrating tool or the like. Furthermore, the column body 12 is pulled out from the foundation 14 without applying an impact load to the column body 12. As a result, the pulling out work and the associated equipment removal work are non-destructive work, and are performed with low vibration and low noise, so as not to cause a nuisance to nearby residents.

[0103] 2. Reduction of the labor required for work (man-hours and construction time)

[0104] 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 in the transport vehicle during loading and unloading, making the work easier. This reduces the labor required for the overall removal work, including the pulling out work.

[0105] 3. Simplification of work and equipment, and reduction of work costs

[0106] In this embodiment, the column body 12 is pulled out without using special or large equipment, for example, by using a handheld manual lifting machine, lifting machine, or pushing 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 the work cost.

[0107] 4. Reusing the extracted columns

[0108] In this embodiment, the cylinder 12 is extracted non-invasively by the chuck 20, i.e., so that no unrepairable marks such as indentations remain on the cylinder 12 after extraction. Since the cylinder 12 is extracted non-invasively, the same cylinder 12 can be reused at another site without additional repairs, which allows for effective use of resources and reduces equipment costs for another site.

[0109] <<Basic chuck configuration>>

[0110] <Basic principle>

[0111] In general, the chuck 20 is removably, elastically and non-invasively attached to the cylinder 12 in order to quasi-statically apply at least an axial force, out of an axial force and a rotational force, to the cylinder 12 in order to pull out the existing cylinder 12 from its installation location (in the example shown in the figure, the base 14).

[0112] <Contact layer>

[0113] The chuck 20 has a cylindrical contact layer 40 (described in detail later with reference to Figs. 16 and 17) that has elasticity at least in the radial direction (at least the former of radial elasticity (compressive elasticity) and longitudinal elasticity (bending elasticity)) and has a soft material at least in its surface layer. When the pillar 12 is a circular column or a cylindrical body, the "cylindrical contact layer" is configured as a cylindrical contact surface or a cylindrical contact surface.

[0114] The chuck 20 is configured to elastically compressively contact the outer peripheral surface of the cylinder 12 via the contact layer 40, with the contact layer 40 surrounding the outer peripheral surface of the cylinder 12 substantially entirely (or partially or locally over an area shorter than one circumference of the outer peripheral surface).

[0115] The chuck 20 is thereby configured to non-invasively grip the post 12 by clamping the post 12 within its elastic range, without leaving any substantial indentation on its outer circumferential surface, and thus may be referred to as a "full-circumference elastic clamping chuck."

[0116] <Outer frame>

[0117] The chuck 20 further includes a frame 50 (described in more detail below with reference to FIGS. 9-15) which holds the interface layer 40 in a supported manner from behind.

[0118] 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.

[0119] <Clamp mechanism>

[0120] In order to assemble the divided bodies 52 in a state in which the chuck 20 grips the columnar 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.

[0121] <<Basic features of the chuck>>

[0122] An important performance of the chuck 20 is that a large friction force is generated between the inner surface of the chuck 20 and the outer surface of the columnar body 12 in relation to the size of the device and the magnitude of the load. On the other hand, the friction force generally increases in proportion to the product of the surface friction coefficient, the drag (radial stress), and the effective contact area.

[0123] 1. Measures for increasing the surface friction coefficient of the contact layer 40

[0124] The contact layer 40 uses a soft material as its surface layer material (for example, the material of the cover layer 42 described below). The soft material includes elastic bodies, synthetic resins, elastomers, and rubbers.

[0125] 2. Optional measures to increase the contact area between the pillars 12 and the contact layer 40

[0126] (1) The contact layer 40 has higher compressive deformation characteristics than when it is formed as a single metal part, thereby increasing the radial 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 crushed and flattened by the load of radial force from the outer frame 50.

[0127] (2) The contact layer 40 has higher bending deformation characteristics than when it is formed as a single metal part, thereby increasing the shape conformity of the contact layer 40 in the axial direction with respect 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.

[0128] (3) The outer frame 50 has a low elastic deformation portion (e.g., a small plate 54 described later as a narrow plate) 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 described later as a wide plate) that is not easily elastically deformed in the radial direction in response to a radial force, each of which is located at a position supporting the contact layer 40 from behind and at a different axial position from each other, thereby increasing the axial shape conformability of the contact layer 40 to the outer surface of the column 12.

[0129] (4) The outer frame 50 has a support surface (e.g., a plurality of vertical grooves 58 described later) 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 later) corresponding to the low elastic deformation portion, and a second partial support surface (e.g., deep groove 62 described later) corresponding to the high elastic deformation portion. The shallow groove 60 and deep groove 62 each have distal portions 64, 66 that are furthest from the contact layer 40.

[0130] As a result, the portion of the contact layer 40 corresponding to the low elastic deformation portion is compressed in the radial direction by a larger amount in the compressed state than the portion of the contact layer 40 corresponding to the high elastic deformation portion, and is configured to be flattened and crushed in the circumferential direction by a larger amount, thereby increasing the contact area between the column 12 and the contact layer 40.

[0131] 3. Optional measures to increase the drag force acting on the contact layer 40

[0132] (1) When the outer frame 50 is divided into a plurality of segments 52 arranged circumferentially around the cylinder 12, the chuck 20 further includes a first force conversion mechanism that converts a portion of the fastening force acting on the plurality of segments 52 when the plurality of segments 52 are connected to each other and fastened to the cylinder 12 into a radial force and applies it to the contact layer 40.

[0133] The first force conversion mechanism includes an inclined member (a second circumferential clamping portion described later) of the clamping mechanism 80 that extends in a direction inclined with respect to the tangential direction at the clamping position B. The inclined member converts a part of the fastening force acting on the multiple divided bodies 52 when the multiple divided bodies 52 are connected to each other and fastened to the columnar body 12 into a radial force. This is expected to equalize 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, the total sum of the resistance in the circumferential direction is increased.

[0134] (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 .

[0135] The second force conversion mechanism includes a laminated structure of the outer frame 50 .

[0136] Specifically, the outer frame 50 is configured not 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 transversely to the column 12, stacked in the axial direction of the column 12 with sliding and tilting movements of the individual plates being permitted.

[0137] When the eccentric load acts on the laminate, sliding deformation and tilting occur in a direction in which the inner end faces of each of the multiple plates 54, 56 fit into the axial region of the contact layer 40. It is presumed that this contributes 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.

[0138] 4. Measures for increasing the durability of the contact layer 40 when the contact layer 40 uses a soft material as its surface layer material

[0139] The contact layer 40 has a double structure in which a metal is used as a back plate that supports the soft material from behind.

[0140] 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 fastening

[0141] At least some of the longitudinal grooves 58 include a depth change portion where the depth changes in the longitudinal direction of the longitudinal grooves 58. The depth change portion is, for example, a portion where a shallow groove 60 and a deep groove 62, which will be described later, contact each other in the longitudinal direction of the longitudinal grooves 58.

[0142] The depth change portion acts as a stopper that prevents the corresponding string-like body 44 from axially disengaging from at least a portion of the longitudinal groove 58 .

[0143] An exemplary and specific component configuration of this chuck 20 will be described in detail later.

[0144] <<Jack>>

[0145] 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 through the chuck 20 and out of the base 14.

[0146] The jack 26 employs a manual type as a driving source (driving method), but may instead employ a fluid type or a motor type. The jack 26 employs a hydraulic type as a boosting method, but may instead employ a lever type, a screw type, a motor type, a compressed air type, or a partial or complete combination of these. The jack 26 employs a direct operation type as an operating method, but may instead employ a remote control type.

[0147] 6 is a side view of the jack 26. A jack similar to the jack 26 is disclosed in, for example, Japanese Patent Application Laid-Open No. 2002-87767.

[0148] The jack 26 has a generally plate-like base 90 that extends horizontally, and a hollow cylindrical (bottle-shaped with a bottom on the upper side) 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 a space within the cylinder 94 and a tank chamber 96 outside the cylinder.

[0149] A ram 100 is fitted in the internal space of the cylinder 94 in a liquid-tight and slidable manner, thereby forming a hydraulic pressure 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 pressure chamber 102 are filled with a common hydraulic fluid (oil, etc.).

[0150] The ram 100 extends perpendicular to the base 90. An upper end of the ram 100 protrudes from the housing 92, and the ram 100 is engageable with the chuck 20 at its protruding end (e.g., a stud).

[0151] The jack 26 further has a pump 104, which is also attached to the base 90. A plunger 106 is fitted in the pump 104 so as to be liquid-tight and slidable, and a pressurizing chamber 108 is formed between one end of the plunger 106 and the base 90. The pressurizing 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.

[0152] The other end of the plunger 106 projects from the pump 104. The projecting end is pivotally connected to one end of a socket 114 (e.g., a handle sleeve) that is pivotally connected about a pin 112 fixed to the housing 92 or base 90.

[0153] 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.

[0154] When the hydraulic chamber 102 is not pressurized, the ram 100 is in its maximum retracted position, ie, its lowest position, as shown by the solid lines in the figure.

[0155] 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 a lift force 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.

[0156] <<Base unit>>

[0157] 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 portion 14 in order to mechanically prevent the foundation portion 14 from lifting out of the soil as the column body 12 is pulled out.

[0158] 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 the center of the base unit 24. The base unit 24 has a base that is placed on the foundation part 14 so as to at least partially cover the foundation part 14.

[0159] <<Mounting fixture>>

[0160] 3, the system 10 further includes an attachment jig 22 for supporting the chuck 20 from below before assembly, in order to assist an operator in mounting the chuck 20 on 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.

[0161] Using this mounting jig 22, the worker temporarily positions the chuck 20 relative to the cylinder 12 both axially and radially, and then uses a clamping mechanism 80 (see Figures 1, 18 and 19) to clamp the multiple segments 52 together with the cylinder 12, thereby assembling the chuck 20 to the cylinder 12.

[0162] This mounting jig 22 may also be configured as a disassembly and assembly type so that it can be assembled and disassembled on site.

[0163] <<Hoist>>

[0164] As illustrated 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.

[0165] The hoist 30 has, for example, a chain block, and is connected to an eyebolt 124 (see Figure 7) as a connector for the chuck 20 using a chain 120 and a hook 122 connected to the end of the chain 120, so that the chain 120 can be wound up and pulled up to lift the chuck 20 together with the column body 12, thereby pulling the column body 12 within the base part 14 and finally removing it from the base part 14.

[0166] The hoist 30 employs a manual type as a driving source (driving method), but may instead employ a motor type, a hydraulic type, a compressed air type, or a partial or total combination of these. Also, the hoist 30 employs a direct operation type as an operating method, but may instead employ a remote control type.

[0167] <<Multi-layered scaffolding>>

[0168] As illustrated 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. In order to further elevate the installation position of the hoist 30, the second level of scaffolding 32 is installed by stacking it on the first level of scaffolding 32, as shown by the two-dot chain line in the figure. Each scaffolding 32 is configured as a disassembly type that can be assembled and disassembled on-site.

[0169] [Example and specific component configuration of the chuck]

[0170] <<Outer frame>>

[0171] As shown in Figure 9, which is a representative enlarged perspective view of one of the multiple divided bodies 52 shown in Figure 1, the outer frame 50 is not configured as a single block (e.g., a metal block) extending in the axial direction of the pillar 12, but as a laminate in which multiple plates 54, 56 extending in a direction transverse to the pillar 12 are stacked in the axial direction of the pillar 12.

[0172] 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 from the outer surface, and a right edge and a left edge located on the right and left sides, respectively, when viewed from the center of the cylinder 12.

[0173] 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.

[0174] 12, a plurality of through holes are formed in each of the multiple large plates 56 so that the multiple large plates 56 can be stacked and clamped 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 clamping force of the multiple segments 52 is uniform in the circumferential direction.

[0175] Some of the plurality of through holes are formed in each large plate 56 at a plurality of positions D, E, F, G, H1, H2 and J.

[0176] 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.

[0177] Moreover, for each large plate 56, one position F is located approximately at the center of the right edge of the large plate 56. Moreover, for each large plate 56, one position G is located approximately at 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 be on concentric circles.

[0178] Moreover, 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 distance from the center of the column 12.

[0179] Also, 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.

[0180] Specifically, groups consisting of positions H1, H2 and J, which are respectively located at the three vertices of a roughly equilateral triangle, are arranged on both sides of the outer periphery, and the 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 same figure) and position E).

[0181] As shown in Fig. 10, the multiple 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 having a predetermined circumferential positional relationship with the large plate 56, multiple through holes are formed in each small plate 54 as shown in Fig. 13. The through holes are formed at position K which is concentric with position D shown in Fig. 12.

[0182] 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 (unthreaded) or long screws (threaded at least on both ends), and other examples include nuts and eye bolts.

[0183] In the figure, long screws are passed through the multiple large plates 56 and the multiple small plates 54 at position D (position K) as rod-shaped fasteners 130, and nuts 132 are fastened to the ends of the long screws protruding from the two outermost large plates 56. Similarly, long screws are passed through the multiple large plates 56 at position E as rod-shaped fasteners 130, and nuts 132 are fastened to the ends of the long screws protruding from the two outermost large plates 56.

[0184] In this case, a spacer 134 (sleeve or collar) is disposed between two adjacent large plates 56 with the rod-shaped fastener 130 passing through it, thereby defining the axial distance between the two adjacent large plates 56.

[0185] 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, hereinafter referred to as "thread gap") is left 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.

[0186] <Effect of constructing the outer frame as a laminated body capable of sliding motion>

[0187] As described above, the outer frame 50 is constructed as a laminate, and a number of thin plates 54, 56 are fastened to each other with a relatively large threaded clearance to form a laminate capable of sliding movement. The effects of this will now be considered.

[0188] FIG. 11(a) shows, as a comparative example, a partial cross-sectional side view of an analysis result of the behavior of the outer frame 50 of the chuck 20 in response to the eccentric load when the outer frame 50 is of one-piece type (block).

[0189] In this comparative example, similar to 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.

[0190] In this comparative example, as in the embodiment, 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 (force point), lowest point) of the outer frame 50 relative to the jack 26 toward a distal point (highest point).

[0191] Under such mechanical conditions, in this comparative example, the outer frame 50 is configured as a metal block that serves as a rigid body. Therefore, in this comparative example, the outer frame 50 tilts (angularly displaces) in response to the bending moment without deforming itself.

[0192] 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 such that, at its proximal point, it moves radially outward away from the outer surface of the cylinder 12, while, at its distal point, it moves radially inward toward the outer surface of the cylinder 12.

[0193] Therefore, in this comparative example, it is assumed that the chuck 20 locally lifts off 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.

[0194] 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 ultimately, the total axial resistance generated in the contact layer 40 is also reduced.

[0195] In contrast, FIG. 1(b) shows, in a partial cross-sectional side view, the results of an analysis 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, as an embodiment of the present invention.

[0196] 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 as a whole in the outer frame 50 itself, and thus the contact layer 40 is 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.

[0197] This suppresses a decrease in the area of ​​the axial region where the contact layer 40 contacts the outer surface of the column 12, despite the eccentric load acting on the outer frame 50, and suppresses the emphasis of the non-uniformity of the distribution pattern of the radial force acting on the outer frame 50. 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 sum of the resistance forces.

[0198] <<Contact layer>>

[0199] As shown in Fig. 17(a), 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 (an example of an "imaginary cylindrical surface") concentric with the cylinder 12 as a plurality of discrete bodies discretely arranged in the circumferential direction of the cylinder 12. As shown in Fig. 17(b) and Fig. 16, each cord-like body 44 includes a core material 46 made mainly of metal, and a coating layer 42 (an example of a "surface layer") that coats 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".

[0200] <Contact layer structure>

[0201] One example of each cord-like body 44 is a resin-coated wire rope, as shown in Fig. 16. The resin-coated wire rope has a wire rope as a core material 46, a synthetic resin sleeve as a coating layer 42, and is configured as a wire rope whose surface is coated with synthetic resin.

[0202] Here, a "wire rope" is formed by twisting together multiple strands (small ropes, small lumps) each of which is made up of multiple strands twisted together 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 constitutes the "coating layer 42" is synthetic resin (PVC, nylon, polyethylene, etc.) (an example of a "soft material").

[0203] <Mechanical properties of the contact layer>

[0204] The coating layer 42 has flexibility (bendability). In addition, the core material 46 is allowed to slip between the plurality of wires and between the plurality of strands, and as a result, has higher flexibility (ease of compressive deformation in the diameter direction (e.g., ease of crumbling or crushing of strands) and ease of bending in a direction crossing the length direction) than the core material 46 made of a single wire.

[0205] Furthermore, due to the elasticity of the respective materials, the covering layer 42 and the core material 46 both return to their unloaded (natural) cross-sectional shape (e.g., circular) and overall shape (straight line) after unloading. Furthermore, the covering 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 covering layer 42.

[0206] 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.).

[0207] In this embodiment, at least one end of each wire rope is terminated. Specifically, a sleeve or clip is crimped to the rope end as a prefabricated metal fitting. The presence of the prefabricated metal fitting at the end prevents each wire rope from falling under its own weight when the wire rope is held on the inner surface of the outer frame 50 as shown in FIG.

[0208] <<Outer frame>>

[0209] <Laminated body capable of sliding motion>

[0210] 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 against a radial force, and a large plate 56 as a high elastic deformation part that is not easily elastically deformed in the radial direction against 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.

[0211] Specifically, the low elastic deformation portion is a small plate 54 having a narrow width dimension W1 as shown in Fig. 14(a), while the high elastic deformation portion is a large plate 56 having a wide width dimension W2 that is longer than the width dimension W1 as shown in the figure.

[0212] In the small plate 54 shown in FIG. 14(a), a plurality of shallow grooves 60 are arranged along a perfect circular arc (an arc of a perfect circle) centered on the center of the chuck 20, as shown in FIG. 14(b).

[0213] Alternatively, as shown in Fig. 1(b), a circular arc shape different from the circular arc shape of the small plate 54 may be adopted. One example of the different circular arc shape is a flattened circular arc having a radius R2 longer than the radius R1 of a true circular arc, as shown in the figure.

[0214] 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 pillar 12 is shorter, and the amount of radial outward deflection of the corresponding multiple small plates 54 increases accordingly.

[0215] As a result, in this example, even if the diameter of the column 12 is the same, a larger repulsive force acts on each of the strings 44 from each of the small plates 54, which increases the resistance acting on the contact layer 40 in the radial direction (thickness direction), and accordingly increases the frictional force generated in the contact force. In this way, the effect of amplifying the frictional force is obtained.

[0216] <Multiple vertical grooves on the outer frame>

[0217] As shown in Fig. 1, the outer frame 50 has a plurality of vertical grooves 58 (an example of a "groove") that contact the respective 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 a plurality of shallow grooves 60 and a plurality of deep grooves 62 that are aligned in a row.

[0218] As illustrated 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 also 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.

[0219] As shown in Fig. 1A, each of the longitudinal grooves 58 (shallow grooves 60 and deep grooves 62) has a cross-sectional shape (a cross-sectional shape that approximately complements the cross-sectional shape of the string-like body 44) that forms a partial circle that opens at the inner edge of the outer frame 50. The multiple longitudinal grooves 58 are configured by multiple shallow grooves 60 (an example of "first partial grooves") formed in each of the multiple small plates 54 and multiple deep grooves 62 (an example of "second partial grooves") formed in each of the multiple large plates 56, which are each arranged in a row in the same phase in the vertical direction.

[0220] 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 them 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.

[0221] As shown in Figures 13 and 15(a)-(c), a plurality 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 plurality of deep grooves 62 are arranged in a row on the inner edge of each large plate 56.

[0222] 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, as viewed from directly above the stack shown in Fig. 9. Fig. 15(b) is a front view showing the plates 54, 56 having the deep groove 62 and the shallow groove 60. Fig. 15(c) is a side cross-sectional view showing the plates 54, 56 having the deep groove 62 and the shallow groove 60.

[0223] Each of the shallow and deep grooves 60, 62 has a proximal portion 64, 66 closest to the exterior surface of the post 12 and a distal portion 68, 70 furthest from the exterior surface.

[0224] The proximal portion 64 of the shallow groove 60 is generally in the same relative position to the exterior 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 exterior surface of the post 12 than the distal portion 70 of the deep groove 62.

[0225] As a result, when each string-like body 44 is compressed by the column 12, the portion corresponding to the small plate 54 and the shallow groove 60 experiences a greater amount of radial compression, as illustrated in Figure 1(d), than the portion corresponding to the large plate 56 and the deep groove 62, and as a result, is flattened and crushed to a greater extent in the circumferential direction.

[0226] This creates an increased drag and therefore friction force between each strand 44 and the post 12 , and also creates an increased contact area between each strand 44 and the post 12 .

[0227] <<Clamp mechanism>>

[0228] <Basic configuration>

[0229] 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 for axially connecting and combining the multiple plates 54, 56 for each divided body 52.

[0230] <Circumferential clamping section>

[0231] As illustrated in FIG. 12, the circumferential clamp portion 82 is configured such that, for example, at clamp 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.

[0232] FIG. 18(a) shows a plan view of a first circumferential clamping portion 84 used at a plurality of clamping positions A, and FIG. 18(b) shows a side view thereof.

[0233] The first circumferential clamp part 84 includes a first long screw 140 that passes through clamp positions H1 and H2, and a second long screw 142 that passes through clamp position J, and 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 and are arranged in parallel in the axial direction. The second long screw 142 at position J passes through the eye portion of the eyebolt 144. A plate 148 is disposed on the opposite side of the second long screw 142, straddling the two first long screws 140, 140 that pass through positions H1 and H2.

[0234] FIG. 19(a) shows a plan view of a second circumferential clamping portion 86 used at a plurality of clamping positions B, and FIG. 19(b) shows a side view thereof.

[0235] The second circumferential clamp portion 86 includes a long screw 160 that passes through clamp position G and a first eye bolt 162 that passes through clamp position F, and further includes at least one set of a second eye bolt 164 and a nut 166 that connect the long screw 160 and the first eye bolt 162 in a direction oblique to the circumferential direction.

[0236] The bolt portion of first eyebolt 162 passes through a through hole at position F and is fastened by nut 168, and the bolt portion of second eyebolt 164 passes through the eye portion of the same eyebolt 162. Long screw 160 at position G passes through the eye portion of second eyebolt 164.

[0237] 12, at clamp position B, the second eyebolt 164 extends in a direction intersecting both the radial and circumferential directions. This second eyebolt 164 acts as the aforementioned diagonal member extending in a direction inclined with respect to the tangential direction at clamp position B.

[0238] As a result of such geometry being provided to the second circumferential clamping portion 86, a radial force in addition to a circumferential force acts on the two adjacent segments 52 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.

[0239] <Axial clamping section>

[0240] As illustrated in FIG. 10, the axial clamping portion 88 is configured for each divided body 52, for example at clamping positions D and E, so that a rod-shaped fastener 130, which is a long screw or shaft, passes through all of the plates 54, 56 or only a few of the large plates 56 to clamp the members.

[0241] Specifically, FIG. 10 shows, as described above, how all of the plates 54, 56 are fastened by the long screws 130 passing through them in clamp position D, and how multiple large plates 56 are fastened by the long screws 130 in clamp position E with a specified gap between them secured by the spacers 134.

[0242] <<How to pull out the column>>

[0243] <Summary>

[0244] FIG. 21 is a process diagram illustrating an example of a method for extracting the cylinder 12 using the system 10 described above.

[0245] According to this column extraction method, the column 12 is extracted from the base 14 in stages, as shown in FIGS.

[0246] That is, this column extraction method includes the steps 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 to separate the column 12 from the foundation 14, thereby partially or completely extracting the column 12 from the foundation 14, and, when the column 12 cannot be extracted from the foundation 14 by using the jack 26 alone, applying an additional quasi-static axial force to the chuck 20, together with the column 12, as shown in FIG. 7, in a direction to separate the column 12 from the foundation 14, by driving the hoist 30, thereby completely extracting the column 12 from the foundation 14.

[0247] 1. First process: Equipment delivery and assembly

[0248] Several pieces of equipment required for the extraction work (base unit 24 shown in Figures 3 and 4, mounting jig 22 shown in Figure 3, chuck 20 shown in the same figure, jack 26 shown in Figure 5, hoist 30 shown in Figure 7, chain 120 shown in the same figure, scaffolding 32 shown in the same figure, etc.) are loaded in a disassembled state from their storage locations onto a transport vehicle such as a truck and transported to the destination site (for example, a used parking lot where the equipment removal is desired).

[0249] Once the equipment arrives at the site, it is assembled by workers.

[0250] 2. Second process: Pulling out with jack 26

[0251] <Summary>

[0252] This process mainly involves driving the jack 26 to apply an axial force to the chuck 20 in a direction that moves it, together with the pillar 12, away from the base 14 as a quasi-static force (quasi-static load) rather than an impulsive force (impact load), thereby pulling out the pillar 12 from the base 14.

[0253] Here, "quasi-static force (quasi-static load)" is defined as a dynamic load excluding impact load, not a static load, in that the magnitude of the force changes over time. Specifically, "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, and the like.

[0254] <Preparation>

[0255] Prior to the extraction operation, the necessary equipment (base unit 24, mounting fixture 22, chuck 20, jack 26, etc.) is assembled on-site.

[0256] Specifically, as shown in FIG. 2(a), in the preparation stage before extraction, the column body 12, the chuck 20 and the base portion 14 are integrally arranged.

[0257] Specifically, in this preparation stage, as shown in Fig. 4, a hollow base unit 24 (one example of a "displacement prevention part") is first installed so as to cover the foundation part 14 in order to prevent the foundation part 14 from lifting up as the pillar body 12 rises. An example of the base unit 24 is shown in a perspective view in Fig. 5. In this example, the pillar body 12 penetrates the center of the base unit 24.

[0258] Next, the hollow mounting jig 22 is placed on the upper surface of the base unit 24 with the column 12 passing through the center thereof.

[0259] Next, the chuck 20 is placed on the upper surface of the mounting jig 22 before the assembly is completed and in a state in which the column 12 is accessible from both diametrical sides. In this state, the multiple segments 52 are clamped by 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.

[0260] Then, a number of jacks 26 are placed on the upper surface of the base plate at positions facing each other so as to sandwich the column 12 from both sides in the diametric direction. At this time, each jack 26 is in the maximum contraction position, and usually, for convenience of installation work, a gap is provided between the upper end surface of the jack 26 and the lower surface of the chuck 20.

[0261] 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 pillar 12.

[0262] 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 Fig. 5. This completes preparation for the pulling work by the jack 26.

[0263] <Main work>

[0264] The operator repeatedly swings the lever 116 of the jack 26. This increases the lifting force of the jack 26, and at this time, the lifting force acts on the chuck 20 from the jack 26 as a concentrated eccentric load, as shown in Figs.

[0265] The jacks 26 are arranged facing each other on either side of 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 almost synchronously with each other. The cooperation 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.

[0266] Before the pull-out, there is a gap between the upper surface of the ram 100 of the jack 26 and the lower surface of the chuck 20, so when the operator drives the jack 26, the lifting force increases until the gap disappears, as shown in the graph in Figure 22, for example, until it becomes strong enough to overcome 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 Figure 12.

[0267] Incidentally, 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 to the pillar 12 a force that overcomes the adhesive force (e.g., adhesive force, joining force, etc.) between them. This force is the force required to separate and peel the pillar 12 from the base 14. Furthermore, it is presumed that it is also necessary to apply to the pillar 12 a force that overcomes the maximum static friction coefficient between the pillar 12 and the base 14.

[0268] Here, the force required for extraction is, for example, a force resisting the column body 12 being pulled out from the base part 14, that is, 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.

[0269] Therefore, if the operator continues to drive the jack 26 after the contact between the jack 26 and 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.

[0270] When the lifting force of the jack 26 overcomes the resistance to pulling out, both the chuck 20 and the column 12 start to rise, but at this time, 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.

[0271] Eventually, the ram 100 of the jack 26 reaches the highest position. At this time, the column 12 has a part remaining in the foundation 14, and the column 12 is not completely pulled out from 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.

[0272] 3. Third step: Additional extraction step with hoist 30

[0273] <Summary>

[0274] This process is mainly performed when the column body 12 cannot be completely pulled out from the foundation 14 by using the jack 26 alone, and the worker operates the hoist 30 as shown in FIG. 7 to quasi-statically apply an additional axial force to the chuck 20 in a direction to separate the column body 12 and the chuck 20 from the foundation 14, thereby completely pulling out the column body 12 from the foundation 14.

[0275] <Preparation>

[0276] As shown in Fig. 7, a worker sets up the first stage scaffolding 32 at a predetermined position relative to the pillar body 12. A hoist 30 is suspended from the upper 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 serving as a connector for the chuck 20.

[0277] <Main work>

[0278] Thereafter, the operator drives the hoist 30 to wind up the chain 120, thereby lifting the chuck 20 together with the pillar body 12. As a result, the pillar body 12 is further lifted from the base portion 14, and finally, the pillar body 12 is completely pulled out from the base portion 14.

[0279] However, if the first stage of scaffolding 32 is not sufficient, a second stage of scaffolding 32 is piled up as shown by the two-dot chain line in FIG.

[0280] As shown in Fig. 2(b), in the stage after the extraction, the pillar 12 and the chuck 20 are disposed integrally, while the pillar 12 is disposed above and separated from the base part 14. After the extraction, a cylindrical hole (hereinafter referred to as a "trace hole") having approximately the same diameter as the pillar 12 appears in the base part 14 as a trace that the pillar 12 has been extracted therefrom.

[0281] At this time, it is expected that no cracks will extend from the trace holes in the base portion 14, or even if any cracks remain, they will be very small, and the base portion 14 will not be destroyed.

[0282] 4. Dismantling and removal of equipment

[0283] When the column body 12 is completely pulled out from the foundation 14 in the above manner, the pulled out column body 12 is placed on the ground by the worker. Furthermore, the chuck 20 is dismantled by the worker, and the chuck 20 is thereby removed from the column body 12. Furthermore, the base unit 24, which is the equipment used in the pulling out operation, is removed from the foundation 14 by the worker.

[0284] When the dismantling work for all the equipment is completed, the equipment is carried by the worker into the transport vehicle and returned to the storage location.

[0285] <<Test Example>>

[0286] Here, specific specifications of the column body 12, the chuck 20, and the jack 26 and hoist 30 as axial force applying devices will be described with reference to an example in which the inventors have actually conducted tests.

[0287] <Column specifications>

[0288] Diameter: 114mm Thickness: 2mm Material: steel Total length: 5.5m Length above ground: 4m Length underground: 1.5m

[0289] <Specifications for the foundation>

[0290] Made of concrete

[0291] <Specifications of the string-like body>

[0292] Model number: PVC3-5-200-1M (JIS G 3525 1998) manufactured by Nikko Steel Corporation Structure: "7-strand 6-ply core": Has 6 strands, each of which is made up of 7 wires, with a fiber core in the center of the strands. Core material: Stranded wire Covering layer: PVC (soft vinyl) Rope diameter (core diameter): 3mm Coating outer diameter (apparent diameter): 5 mm

[0293] <Jack specifications>

[0294] Allowable load (maximum lifting force): 4 tons Lowest position: 194mm Highest position: 372mm Lifting height: 178mm Weight: 3.3kg

[0295] In this test example, as in the previously described embodiment, two jacks 26 were used in parallel for one pillar body 12, so that the total maximum lifting force was 8 tons, which is twice the maximum lifting force of one jack 26.

[0296] <Hoist specifications>

[0297] Rated load (maximum lifting force): 0.3 ton Lifting height: 2.5m

[0298] In this test example, as in the previous embodiment, one hoist 30 was used for one column body 12, so the final maximum lifting force remained at 0.3 tons.

[0299] <Test Results>

[0300] The inventors have produced a prototype of this system 10 using equipment having these specifications, and have performed a test extraction operation on-site on a column body 12 and a base portion 14 having the above specifications.

[0301] As a result, the inventor recognized that, as described above, in the extraction work process by the jack 26, the lifting force of the jack 26 showed the time transition illustrated in Fig. 22. Furthermore, the inventor confirmed that there was no trace on the part of the column body 12 where the chuck 20 was attached after extraction, and there was no harmful trace on the base part 14, as described above.

[0302] Therefore, the inventors recognized that it would have been possible to reuse the removed column body 12 at another location without substantial repair. Furthermore, the inventors 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.

[0303] Furthermore, the inventors have confirmed through this test that the extraction work can be performed with low vibration and low noise, that the labor required for the work (man-hours and construction time) can be reduced (the work time was, for example, about 3 hours), and that the work costs could be reduced.

[0304] <<Other Effects of the Present Embodiment>>

[0305] According to this embodiment, the following effects can be obtained.

[0306] Although the cylinder 12 is rigid, 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.

[0307] <<Various Modifications to the Present Embodiment>>

[0308] While several exemplary embodiments of the present invention have been described above, the present invention may be embodied in other forms.

[0309] <Modifications of the shape of the part gripped by the chuck>

[0310] 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.

[0311] On the other hand, when the longitudinal member has a curved portion, the chuck 20 may be configured to be attached to the curved portion. Also, when the longitudinal member has an angle portion, the chuck 20 may be configured to be attached to the angle portion.

[0312] 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 other than a straight line, such as a curved or angled portion, it is easy for the chuck 20 to fit the shape.

[0313] <Modifications of the cross-sectional shape of the column>

[0314] Furthermore, 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.

[0315] Furthermore, in this embodiment, the cylinder 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.

[0316] The present invention may also be practiced in a manner in which a longitudinal member having a solid structure and an outer circumferential surface that is continuous in the circumferential direction or that has an outer circumferential surface that is discontinuous in the circumferential direction is gripped by the chuck 20.

[0317] <Modifications of column installation method>

[0318] 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.

[0319] Specifically, Fig. 1(a) shows a first installation method in which the column 12 is embedded and fixed in a foundation 14 that is embedded in the ground. In this embodiment, the column 12 is configured as a longitudinal member that is installed according to the first installation method. In this case, as described above, the column 12 as a longitudinal member is pulled out from the foundation 14, leaving the foundation 14 in the ground.

[0320] Also, Fig. 1(b) shows a second installation method in which the column 12 is directly buried and fixed in the ground. The present invention may be implemented in a mode 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 from the soil by itself.

[0321] Also, the same figure (c) shows a third installation method in which the column 12 is buried and fixed in a foundation 14 buried in the ground, with an expanded bottom portion 16 (such as a member having a shape that protrudes from the cross-sectional shape of the main body of the column 12) joined to its bottom end in a position where it is exposed from the foundation 14.

[0322] The present invention may also be practiced in a mode in which the chuck 20 is attached to the 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.

[0323] <Modification of the structure of the contact layer>

[0324] 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 discretely arranged in the circumferential direction of the cylinder 12, as shown in Figures 17(a) and (b).

[0325] Alternatively, the contact layer 40 may be configured in such a manner that, as an example, a plurality of string-like bodies 44, each having an oval cross-section, are arranged discretely around the circumference of the cylinder 12, along an imaginary cylindrical surface concentric with the cylinder 12, as shown in Figures (c) and (d).

[0326] As another example, the contact layer 40 may be implemented in an embodiment in which the contact layer 40 has a structure 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 concentric with the cylinder 12, as shown in the same figure (e).

[0327] <Modification of the arrangement method of the string-like bodies>

[0328] In this embodiment, a plurality of string-like bodies 44 are arranged so as to extend in parallel to the axis of the column body 12 along an imaginary cylindrical surface that is substantially concentric with the column body 12 .

[0329] Alternatively, the present invention may be embodied in such a manner that the strings 44 are arranged in parallel and helically extending around the axis of the imaginary cylindrical surface. This arrangement makes it easy to reduce the number of strings 44 required to achieve the same contact area between the strings 44 and the column 12.

[0330] <Modifications of the cross-sectional shape of the column>

[0331] In this embodiment, the pillar 12 is a cylindrical body (solid), a cylindrical body, or a round pipe (hollow). Alternatively, the pillar 12 may be configured as a rectangular pillar (solid), a rectangular tube, or a rectangular pipe (hollow), for example, as illustrated in FIG. 20.

[0332] Specifically, Fig. 1(a) is a plan view showing a chuck 20 suitable for a rectangular prism or a rectangular cylinder, which is another example of the cylinder 12, and Fig. 1(b) is an enlarged plan view showing the contact layer 40 shown in Fig. 1(a). In this case, a "virtual rectangular cylinder surface" is adopted as the "virtual cylindrical surface".

[0333] <Modification of the driving method for lifting the chuck>

[0334] In this embodiment, in the initial stage of the extraction process of the cylinder body 12 when the resistance to the extraction of the cylinder 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 lifted by pushing up the chuck 20 with the jack 26.

[0335] Then, in a subsequent stage when the pulling resistance force decreases, a hoist 30 (low power, high lift or low power, long stroke) is used as a second driving source instead of the jack 26, and the chuck 20 is raised by pulling up the chuck 20 with the hoist 30.

[0336] 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) 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, a large load is required in the initial stage but a short lift is acceptable, whereas a long lift is required in the subsequent stage but a small load is acceptable. In view of this, a plurality of types of drive sources are used depending on the magnitude of the required load and the length of the maximum stroke, i.e., depending on the stage of the extraction process.

[0337] 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 drawing process (e.g., the initial stage and the subsequent stage) throughout all stages of the drawing process, the drawing of the cylinder 12 can be completed by using only one type of drive source throughout all stages of the drawing process.

[0338] For example, the present invention may be implemented in such a manner 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 by the driving source throughout the entire process, thereby pulling out the column 12 without switching the driving source.

[0339] 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 division bodies 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 division body 52 to move horizontally.

[0340] Therefore, at a removal site where there are obstacles (walls, nearby buildings, etc.) near the pillar body 12, such as those illustrated in Figure 23, it is difficult or impossible for a worker to attach the chuck 20 to the pillar body 12.

[0341] <Another embodiment>

[0342] To address this issue, the chuck 20 may be configured as, for example, an asymmetric hinge assembly chuck 170 as illustrated in FIG.

[0343] This chuck 170 has an asymmetric shape in which, for example, when viewed in a plane, it is narrow or small at the back side where the gap is narrow because the cylinder 12 is closer to the obstacle, and wide or large at the front side where the gap is wide because the cylinder 12 is farther from the obstacle.

[0344] Furthermore, this chuck 170 is configured to include, for example, a narrow base end portion 172 located at the rear side, a pair of arm portions 174, 174 connected to the narrow base end portion 172 by a hinge 173 and capable of clamping the cylinder body 12 from both diametrical sides, and a slide portion 176 between the arm portions 174, 174 and capable of sliding relative to the arm portions 174, 174.

[0345] 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 surfaces 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 above-mentioned contact layer 40 is formed on each of the partial cylindrical surfaces.

[0346] Furthermore, in this example, the worker places the chuck 170 in the deployed state so as to pass through the back side of the column body 12 .

[0347] The operator then brings the pair of arm portions 174, 174 closer to each other to compress the cylinder 12 in one diameter direction U, and brings the base end portion 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.

[0348] In this example, the base end 172 and the pair of arm portions 174, 174 can be interpreted as constituting a lever mechanism in which a pair of levers are each connected to the base end so as to be swingable on a single plane (e.g., a horizontal plane), and which supports the contact layer 178 from behind.

[0349] It should be noted that, although it has been pointed out 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 realized in the chuck.

[0350] Although some 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 include 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

1. A chuck removably attached to an existing longitudinal member for extracting the longitudinal member from its installation location, a string-like body array including a plurality of elastic string-like bodies extending parallel to an axis of the longitudinal member or spirally around the axis of the longitudinal member along an imaginary cylindrical surface coaxial with the longitudinal member, and discretely arranged in a circumferential direction of the longitudinal member; an outer frame that holds the outer surface of the string array in a state of supporting it from the outside, and that contacts the outer surface of the string array with its inner surface, thereby gripping the longitudinal member by bringing the inner surface of the string array into contact with the outer peripheral surface of the longitudinal member in a compressed state within its elastic range; Including, the outer frame includes, on its inner surface, a plurality of grooves that partially receive the plurality of strings on their respective outer surfaces; At least some of the grooves include depth changing portions whose depths change in the longitudinal direction.

2. Each of the plurality of grooves has a shallow groove and a deep groove aligned in the longitudinal direction, 2. The chuck for extracting a longitudinal member according to claim 1, wherein the depth-changing portion is formed at a portion where the shallow groove and the deep groove contact each other in the longitudinal direction.

3. the outer frame has an inner surface thereof that supports the plurality of string-like bodies; The support surface has a first partial support surface corresponding to the shallow groove and a second partial support surface corresponding to the deep groove, each of the shallow groove and the deep groove has a distal portion furthest from an outer surface of the plurality of string-like bodies; 3. The chuck for extracting a longitudinal member according to claim 2, wherein the distal portion of the shallow groove is closer to the outer peripheral surface of the longitudinal member than the distal portion of the deep groove.

4. 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.

5. 5. The chuck for extracting a longitudinal member according to claim 4, wherein the soft material includes an elastic body, a synthetic resin, an elastomer, or a rubber.

6. 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.

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