Chuck for extracting longitudinal members

Abstract

This technology provides the ability to grip existing longitudinal members and easily remove them from their installation location with low noise and low vibration. [Solution] The chuck 170, which is detachably attached to the longitudinal member 10 to pull the existing longitudinal member 10 out of its installation location, has a cylindrical contact layer 178 that is elastic at least in the radial direction and capable of contacting the outer circumferential surface of the longitudinal member so as to surround it all around or partially, and a lever mechanism in which a pair of levers 174, 174 are connected to the base end 172 so as to be swingable on a single plane in a position extending from the base end, wherein the pair of levers support the contact layer from behind on their respective inner surfaces, in a state in which the outer circumferential surface of the longitudinal member is clamped from both sides in the diametrical direction on their respective inner surfaces, thereby enabling the contact layer to tighten the longitudinal member within its elastic range.

Description

Technical Field

[0001] The present invention relates to a technique for pulling out an existing long member from its installation location.

Background Art

[0002] As a member constituting a structure, a long member (e.g., column, pile, beam, etc.) is fixed to a support portion (e.g., ground, wall), or as a member separate from the structure and supporting it at a position floating from a reference plane (e.g., ground surface, wall surface). In the latter case, the structure is supported by the long member fixed to the support portion.

[0003] Here, the "long member" has, for example, hollow and solid as classifications of cross-sectional structures, metal and concrete as classifications of materials, rod, shaft, pipe, and cylinder as classifications in form, and column, pile, beam, and reinforcing bar as classifications in function. In any case, the "long member" may be an already buried body, or a prefabricated member or a member fabricated on-site.

[0004] Also, the "support portion" is, for example, soil or a wall. When the "support portion" is soil, the "long member" is, for example, a column or a pile. When the "support portion" is a wall, the "long member" is, for example, a beam.

[0005] Taking a parking lot as an example to specifically explain those structural materials, as an example of the "long member", there are a power pole (an example of a "column") that supports electrical components such as electric lights at a position floating from the ground, and one or more support columns (an example of a "column") that support a sign displaying toll information or the like at a position floating from the ground.

[0006] These structural members are fixed to the ground (an example of a "supporting section") at their respective lower ends. A concrete foundation is embedded in the ground. In this case, the lower ends of each of these structural members are embedded and fixed to the concrete foundation.

[0007] There are two methods for fixing longitudinal members to the ground: the driven method and the embedded method.

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

[0009] In contrast, the embedded construction method involves excavating the ground to a predetermined depth to create a pilot hole, and then inserting a pre-fabricated longitudinal member (for example, a pre-fabricated pile or column) into that pilot hole. One such embedded construction method is called the root wrapping method (see, for example, Patent Document 1). This root wrapping method involves, for example, creating an enlarged concrete bulb at the lower end of the longitudinal member. In this case, the enlarged bulb, or root wrapping or root reinforcement section, may be constructed using reinforcing bars or without them.

[0010] According to this root-wrapping method, a pilot hole is first excavated in the ground, and crushed stone is placed at the bottom of the pilot hole and compacted. Next, a support post is inserted into the pilot hole, and temporary bracing is used to keep the post upright and prevent it from tilting. After that, ready-mix concrete is poured into the pilot hole, surrounding the support post. The concrete is then allowed to harden, thereby fixing the support post in place.

[0011] For example, as disclosed in Patent Document 1 mentioned above, a longitudinal member fixed to the ground cannot remain in the same place semi-permanently. For example, if the installation site is leased land, the landowner may suddenly demand that the longitudinal member be removed from the installation site and the site be returned to its original state.

[0012] On the other hand, longitudinal members may be firmly fixed to the ground using concrete foundations (for example, under high pull-out resistance (resistance force when the longitudinal member is pulled out from the foundation)). In this case, removing the longitudinal member may require considerable effort (man-hours, construction period, etc.) and cost (labor costs, equipment costs, etc.).

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

[0014] Specifically, when land owned by a landowner is potentially or planned to be sold, the land becomes idle or vacant until the sale is finalized. In such cases, the landowner may temporarily operate a parking lot on the land to generate rental income until the sale is complete. In this case, the landowner may entrust the operation of the parking lot to a professional parking lot operator (or parking lot management company, etc.).

[0015] In this case, if the landowner decides to use their land for a different purpose or to sell it, they will request the parking lot operator to return their land to its original state. To comply with this request, the parking lot operator will need to remove all equipment installed on the land for the purpose of operating the parking lot.

[0016] In this situation, the parking lot operator would ideally like to carry out the removal work with as little effort, in as little time, and at the lowest possible cost.

[0017] Incidentally, throughout this specification, the term “extract” is used to mean, for example, the action of pulling an object in a direction that causes the object to detach from the object in which it is attached.

[0018] However, the term "pull out" contains the word "nuki," which means that an object detaches or separates from its target object. Therefore, when using the term "pull out," it can be interpreted in a narrow sense, meaning that the object must detach from its target object.

[0019] However, depending on the context, this term can be interpreted more broadly to mean the action of pulling an object within an object in a direction that causes the object to detach from the object, regardless of whether the object ultimately detaches from the object.

[0020] In contrast, when it is necessary to clearly distinguish from other events the event in which an object is pulled away from another object due to an action that causes the object to detach from the object, the term "completely withdrawn" may be used.

[0021] Furthermore, the axial force applied to a longitudinal member to pull it out of its installation location may be defined as either a pushing force or a pulling force. This is because whether the axial force applied to the longitudinal member is a pushing force or a pulling force, the longitudinal member will still be pulled out of the support or foundation.

[0022] Conventional techniques for removing longitudinal members by pulling them out of their installation location are disclosed in Patent Documents 1-4.

[0023] Patent Document 1 discloses a technique for extracting a column (an example of a "longitudinal member") from the soil along with the foundation in which it is buried.

[0024] Specifically, according to this technology, first, multiple metal chips are welded to the outer surface of the upper part of the column that is exposed from the foundation. Next, a wire for pulling out the column is hooked onto these metal chips. Then, the tip of the wire is lifted using heavy machinery such as a crane, thereby pulling the column out of the ground along with the surrounding foundation.

[0025] Patent Document 2 discloses, as a method for extracting a steel material (an example of a "long member") from the ground, (a) a method of directly extracting the steel material with a hydraulic or vibratory extractor, (b) a method of previously interposing various lubricating materials as a cutting edge around the steel material, thereby weakening the extraction resistance (the resistance when extracting the steel material), and under that condition, extracting the steel material, and (c) a method of using blasting agents.

[0026] Patent Document 3 discloses a method of introducing an inclusion for reducing the extraction resistance of a steel material (an example of a "long member") between the steel material and a cement-based hardened material at the installation stage.

[0027] Specifically, according to that technique, prior to inserting the steel material into the cement-based hardened material before curing, a resin coating that is deteriorated by an alkaline component in the cement-based hardened material is applied to a portion of the steel material that comes into contact with the cement-based hardened material, whereby the resin coating is deteriorated by the alkaline component and the extraction of the steel material becomes easier.

[0028] Patent Document 4 discloses a method of removing a pile (an example of a "long member") that has already been buried. Specifically, this is a method of digging out the ground around the pile, cutting the edge between the ground and the pile, and extracting and removing the pile from the soil with soil adhering thereto.

[0029] In addition, prior art of a chuck attached to a long member for extracting the long member from its installation location is disclosed in Patent Documents 5-7. Exists.

[0030] Patent Document 5 discloses a chuck that holds a pile (an example of a "long member") by sandwiching it with a pair of jaws from both sides in its diameter direction.

[0031] The pair of jaws are positioned at different locations in the axial direction so that, when they are in a holding position, they clamp the pile so that they are opposed to each other in a side view. Furthermore, in the holding position, the chucks are lifted up by a hoist along with the pile, thereby pulling the pile out from the ground or other surface.

[0032] Patent Document 6 discloses a chuck that grips a column member (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 surface of the column member (an example of a "longitudinal member") using the principle of a wedge.

[0033] Patent Document 7 discloses a chuck that grips a reinforcing bar (an example of a "longitudinal member") by pressing two or four divided bodies, arranged at equal angular intervals in a plan view, against the outer surface of the reinforcing bar using the principle of a wedge. [Prior art documents] [Patent Documents]

[0034] [Patent Document 1] Japanese Patent Publication No. 2014-001542 [Patent Document 2] Japanese Patent Application Publication No. 2-176014 [Patent Document 3] Japanese Patent Application Publication No. 59-078809 [Patent Document 4] Japanese Patent Publication No. 2011-196114 [Patent Document 5] Japanese Patent Publication No. 2002-038482 [Patent Document 6] Japanese Patent Publication No. 2002-180466 [Patent Document 7] Japanese Patent Publication No. 2011-107000 [Overview of the project] [Problems that the invention aims to solve]

[0035] Regardless of whether the method selectively used to fix the longitudinal member to the ground, wall, or foundation is the aforementioned driven-in method or embedded method, the inventors have set the following problem for removing the existing longitudinal member from the ground, wall, or foundation.

[0036] 1. To facilitate the reduction of vibrations and noise generated during the removal of longitudinal members.

[0037] Reducing vibrations and noise associated with the removal of longitudinal members would have several advantages, such as enabling removal work to be carried out without disturbing nearby residents, and allowing removal work to be performed at night when it is quieter than during the day.

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

[0039] Simplifying the work and equipment required for removing longitudinal members reduces the workload on workers and lowers operating costs.

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

[0041] If the traces of the removal work left on the removed longitudinal members are reduced, it becomes possible to reuse the removed longitudinal members to the extent that it does not impede any problems, resulting in the effect of efficient resource utilization and reduction of equipment costs.

[0042] Against the backdrop of the circumstances described above, the present invention aims to provide a technology that enables non-invasive or invasive gripping of existing longitudinal members and their easy removal from their installation site with low noise and low vibration. [Means for solving the problem]

[0043] To solve this problem, according to one aspect of the present invention, a chuck is detachably attached to an existing longitudinal member in order to pull the longitudinal member out of its installation location, A cylindrical contact layer that is elastic at least in the radial direction and capable of contacting the outer surface of the longitudinal member in a manner that completely or partially surrounds the outer surface of the longitudinal member, A lever mechanism in which a pair of levers are connected to a base end so as to be swingable on a plane, with each lever extending from the base end, wherein the pair of levers compress the outer surface of the longitudinal member from both sides in the diametrical direction with their respective inner surfaces, and the pair of levers support the contact layer from behind with their respective inner surfaces, thereby enabling the contact layer to tighten the longitudinal member within its elastic range. A chuck for pulling out longitudinal members is provided, including the following.

[0044] Furthermore, according to a first aspect of the present invention, a chuck is detachably attached to the longitudinal member for pulling out the existing longitudinal member from the support or the foundation embedded in the support, or for pulling out the longitudinal member together with the foundation, A chuck for pulling out a longitudinal member is provided, which non-invasively grips the longitudinal member by tightening it within its elastic range, with the contact layer being circumferentially or partially surrounding the outer surface of the longitudinal member via a cylindrical contact layer that is elastic at least radially and has a soft material at least on its surface.

[0045] Furthermore, according to a second aspect of the present invention, a chuck that is detachably attached to a longitudinal member for the purpose of quasi-statically applying at least an axial force among axial force and rotational force to the longitudinal member in the application of pulling the existing longitudinal member out of the support or a foundation embedded in the support, or pulling the foundation together with the longitudinal member, A cylindrical contact layer that locally surrounds the outer circumferential surface of the longitudinal member in the axial direction, and entirely or partially surrounds it in the circumferential direction, having elasticity at least in the radial direction and having a soft material at least in its surface layer, and having an inner circumferential surface that contacts the outer circumferential surface of the longitudinal member, An outer frame that holds the contact layer in a position that supports it from behind. Includes, The contact layer provides a longitudinal member extraction chuck that non-invasively grips the longitudinal member by tightening it within its elastic range.

[0046] Furthermore, according to a third aspect of the present invention, 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 foundation together with the support, The aforementioned chuck and, A first unit that engages with the chuck and quasi-statically applies an axial force to the chuck in a direction that moves it away from the support or the base, together with the longitudinal member. A longitudinal member extraction system is provided, which includes the following:

[0047] Furthermore, according to a fourth aspect of the present invention, a method for pulling out an existing longitudinal member from a support or a foundation embedded in the support, or pulling out the support together with the foundation, A step of non-invasively gripping the longitudinal member by tightening it within its elastic range using the chuck, A step of applying a quasi-static axial force to the chuck in a direction that separates it together with the longitudinal member from the support portion or the base portion. A method for extracting longitudinal members is provided, including the method for extracting longitudinal members.

[0048] Furthermore, according to a fifth aspect of the present invention, a chuck that is detachably attached to an existing longitudinal member in order to pull the longitudinal member out of its installation location, It includes a tubular contact layer that is elastic at least in the radial direction and has a soft material at least in its surface layer, The contact layer provides a longitudinal member extraction chuck that clamps the longitudinal member within its elastic range, either all around or partially surrounding the outer surface of the longitudinal member.

[0049] Furthermore, according to a sixth aspect of the present invention, a chuck is detachably attached to an existing longitudinal member for the purpose of pulling the longitudinal member out of its installation location, A cylindrical contact layer having elasticity at least in the radial direction and having a soft material at least in the surface layer, A lever mechanism in which a pair of levers are each pivotably connected to a base end, wherein the base end and at least one of the levers support the contact layer from behind on their respective inner surfaces. Includes, The contact layer provides a longitudinal member extraction chuck that clamps the longitudinal member within its elastic range, either all around or partially surrounding the outer surface of the longitudinal member.

[0050] The present invention provides the following embodiments. Each embodiment is divided into sections, each section numbered, and the numbers of other sections are referenced as necessary. This is to facilitate understanding of some of the technical features and combinations thereof that the present invention may employ, and it should not be interpreted that the technical features and combinations thereof that the present invention may employ are limited to the embodiments below. In other words, it should be interpreted that there is no preclude from appropriately extracting and adopting technical features described in this specification that are not described in the embodiments below as technical features of the present invention.

[0051] Furthermore, the fact that each section is written in a format that references the numbering of other sections does not necessarily mean that it prevents the technical features described in each section from being separated and made independent from those described in other sections. Rather, it should be interpreted that it is possible to make the technical features described in each section independent as appropriate according to their nature.

[0052] (1) A chuck that is detachably attached to the longitudinal member for pulling out the existing longitudinal member from the support or the foundation embedded in the support, or for pulling out the longitudinal member together with the foundation, A chuck for extracting a longitudinal member, which non-invasively grips the longitudinal member by tightening it within its elastic range, with a cylindrical contact layer having elasticity at least in the radial direction and a soft material at least on its surface, such that the contact layer surrounds the outer surface of the longitudinal member all around or partially.

[0053] (2) A chuck that is detachably attached to a longitudinal member for the purpose of pulling out an existing longitudinal member from a support or a foundation embedded in the support, or pulling out the support together with the foundation, to apply at least an axial force among axial force and rotational force to the longitudinal member in a quasi-static manner, A cylindrical contact layer that locally surrounds the outer circumferential surface of the longitudinal member in the axial direction, and entirely or partially surrounds it in the circumferential direction, having elasticity at least in the radial direction and having a soft material at least in its surface layer, and having an inner circumferential surface that contacts the outer circumferential surface of the longitudinal member, An outer frame that holds the contact layer in a position that supports it from behind. Includes, The contact layer is a chuck for pulling out a longitudinal member that non-invasively grips the longitudinal member by tightening it within its elastic range.

[0054] (3) The longitudinal member extraction chuck according to item (2), wherein the contact layer non-invasively contacts the outer surface of the longitudinal member under mechanical conditions such that substantially no indentation remains on the portion of the longitudinal member that was gripped by the chuck after the chuck is released from the longitudinal member.

[0055] (4) The longitudinal member extraction chuck according to any one of items (1) to (3), wherein the contact layer comprises a soft material as its surface material.

[0056] (5) The chuck for pulling out longitudinal members as described in item (4), wherein the soft material is an elastic body, synthetic resin, elastomer or rubber.

[0057] (6) The contact layer has higher compressive deformation characteristics than when the contact layer is composed of a metal part, The contact layer has higher bending deformation characteristics than when the contact layer is composed of a metal part. A longitudinal member extraction chuck according to any one of items (1) to (5), employing at least one of the following:

[0058] (7) The longitudinal member extraction chuck according to item (6), wherein the contact layer comprises a soft material as its surface material, which has higher compressive deformation characteristics than when the contact layer is composed of a metal part.

[0059] (8) The longitudinal member extraction chuck according to item (2) or (3), wherein the outer frame has a low-elasticity deformation portion that is easily elastically deformed in the radial direction with respect to a radial force and a high-elasticity deformation portion that is not easily elastically deformed in the radial direction with respect to a radial force, each at a position that supports the contact layer from behind and at different axial positions from each other.

[0060] (9) The outer frame has a low-elasticity deformation portion that is easily elastically deformed radially with respect to a radial force, and a high-elasticity deformation portion that is difficult to elastically deform radially with respect to a radial force, each at different axial positions. The outer frame has a support surface that contacts the contact layer from behind and accommodates it. The support surface has a first partial support surface corresponding to the low-elasticity deformation portion and a second partial support surface corresponding to the high-elasticity deformation portion. Both of these first and second partial support surfaces have a distal portion that is furthest from the contact layer. The longitudinal member extraction chuck according to item (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) When the outer frame is divided into a plurality of segments arranged in the circumferential direction of the longitudinal member, the chuck further includes a first force conversion mechanism that converts a portion of the clamping force acting on the plurality of segments when the plurality of segments are connected and clamped to the longitudinal member into a radial force and acts on the contact layer, When the load acting on the outer frame from the outside to pull out the longitudinal member is an eccentric load acting in a straight line offset from the axis of the longitudinal member, the chuck further includes a second force conversion mechanism that converts a portion of the eccentric load into a radial force and applies it to the contact layer. A longitudinal member extraction chuck according to item (2) or (3), employing at least one of the above.

[0062] (11) The outer frame is divided into a plurality of segments arranged in the circumferential direction of the longitudinal member, These divided parts are connected to each other by a clamping mechanism in the longitudinal member extraction chuck described in section (2) or (3).

[0063] (12) The longitudinal member extraction chuck according to item (11), wherein the plurality of divisions are four divisions in which the outer frame is divided at substantially equal angles.

[0064] (13) The clamping mechanism connects two adjacent divided bodies to each other, The clamping mechanism is a longitudinal member extraction chuck according to item (11) or (12), which includes an oblique member extending in a direction inclined with respect to the tangential direction about the axis of the longitudinal member at the connection point.

[0065] (14) The longitudinal member extraction chuck according to item (2) or (3), wherein the outer frame is configured not as a block extending in the axial direction of the longitudinal member, but as a laminate in which a plurality of plates extending in a direction transverse to the longitudinal member are stacked in the axial direction of the longitudinal member, such that sliding motion and tilting of the individual plates are permitted.

[0066] (15) A longitudinal member extraction chuck according to any one of items (1) to (14), wherein the contact layer includes a soft material as its surface material, and the contact layer employs a double structure in which metal is used as a backing plate to support the soft material from behind.

[0067] (16) The contact layer is composed of a plurality of string-like bodies arranged to extend generally parallel to one another, The longitudinal member extraction chuck according to any one of items (1) to (15), wherein the string-like bodies are arranged in the compressed state to extend parallel to the axis of a virtual cylindrical surface that is substantially concentric with the longitudinal member, or spirally around that axis.

[0068] (17) A longitudinal member extraction chuck as described in item (16), wherein each string-like body comprises a core made mainly of metal and a covering layer covering the core made mainly of a soft material.

[0069] (18) The longitudinal member extraction chuck according to item (17), wherein the soft material comprises an elastic body, synthetic resin, elastomer or rubber.

[0070] (19) Each string-like body is made of a resin-coated wire rope, which is a wire rope covered with synthetic resin, The resin-coated wire rope, in its natural state when not attached to the chuck, generally extends in a straight line, longitudinal member extraction chuck as described in paragraph (17) or (18).

[0071] (20) The coating layer has a higher surface friction coefficient than the core material, The core material has higher elastic recovery properties than the coating layer. A longitudinal member extraction chuck according to any one of items (17) to (19).

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

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

[0074] (23) The outer frame has a low-elasticity deformation portion that is easily elastically deformed in the radial direction with respect to a radial force, and a high-elasticity deformation portion that is difficult to elastically deform in the radial direction with respect to a radial force, each at different axial positions. The outer frame has multiple grooves that contact each of the multiple string-like bodies from behind and accommodate those string-like bodies, Each groove has a shallow groove corresponding to the low-elasticity deformation portion and a deep groove corresponding to the high-elasticity deformation portion. Both the shallow grooves and the deep grooves have a distal portion that is furthest from the outer surface of the column, The longitudinal member extraction chuck according to item (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) The longitudinal member is hollow or solid, as described in any of items (1) to (23), for a longitudinal member extraction chuck.

[0076] (25) The longitudinal member extraction chuck according to any one of items (1) to (24), wherein the longitudinal member is made of metal or concrete.

[0077] (26) The longitudinal member is a rod, shaft, tube or cylinder, as described in any of items (1) to (25).

[0078] (27) The longitudinal member is a column, pile or beam or reinforcing bar, as described in any of items (1) to (26), a longitudinal member extraction chuck.

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

[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 foundation together with the support, A chuck as described in any of items (1) through (28), A first unit that engages with the chuck and quasi-statically applies an axial force to the chuck in a direction that moves it away from the support or the base, together with the longitudinal member. A longitudinal member extraction system including a longitudinal member extraction system.

[0081] (30) Furthermore, A longitudinal member extraction system according to paragraph (29), further comprising a second unit which engages with the chuck and quasi-statically applies an additional axial force to the chuck in a manner that further separates the longitudinal member from the support or the base, if the longitudinal member cannot be extracted from the support or the base by means of the first unit alone.

[0082] (31) The longitudinal member is embedded in the foundation, The longitudinal member extraction system further includes: A longitudinal member extraction system according to item (29) or (30), comprising a displacement restraint device that restrains the foundation so that the foundation does not displace from its original position as the longitudinal member is extracted from the foundation while leaving the foundation in its original position.

[0083] (32) A method for pulling out a longitudinal member from the support or the foundation using the longitudinal member pulling system described in paragraph (29), A step of non-invasively gripping the longitudinal member by tightening it within its elastic range using the chuck, The steps include: setting the first unit to engage with the chuck, The process involves driving the first unit to quasi-statically apply an axial force to the chuck in a direction that separates it together with the longitudinal member from the support portion or the base portion. A method for extracting longitudinal members, including the method described above.

[0084] (33) A method for pulling out a longitudinal member from the support or the foundation using the longitudinal member pulling system described in paragraph (30), A step of non-invasively gripping the longitudinal member by tightening it within its elastic range using the chuck, The steps include: setting the first unit to engage with the chuck, The process involves driving the first unit to apply an axial force to the chuck, not as an impact force but as a quasi-static force, in a direction that separates it from the support portion together with the longitudinal member, If the longitudinal member cannot be completely removed from the support or the base by using only the first unit, the second unit is set up to engage with the chuck; The process involves driving the second unit to quasi-statically apply an additional axial force to the chuck in a direction that separates it together with the longitudinal member from the support or the base, and A method for extracting longitudinal members, including the method described above.

[0085] (34) A method for pulling out a longitudinal member according to item (32) or (33), which does not include the step of rotating the chuck integrally with the longitudinal member.

[0086] (35) When the longitudinal member is a rigid body, the contact between the longitudinal member and the contact layer appears as a rigid-soft contact, and this rigid-soft contact improves the fit of the surface of the contact layer to the surface of the longitudinal member compared to contact between rigid bodies, as described in item (4) or (5).

[0087] (36) A chuck for pulling out a longitudinal member according to any one of items (1) to (28), wherein the chuck is configured to be mounted on the straight portion if the longitudinal member has a straight portion, the curved portion if the longitudinal member has a curved portion, or the angled portion if the longitudinal member has an angled portion, so as to fit the shape of the straight portion, curved portion or angled portion.

[0088] (37) A chuck for pulling out a longitudinal member according to any one of items (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 pulling out a longitudinal member according to any one of items (1) to (28), wherein the longitudinal member has a hollow or solid structure and is configured to have an outer surface that is continuous in the circumferential direction or an outer surface that has a discontinuous portion in the circumferential direction. [Brief explanation of the drawing]

[0090] [Figure 1] Figure 1 is an exploded perspective view showing a column extraction system according to an exemplary embodiment of the present invention. [Figure 2] Figure 2(a) is a perspective view showing the column, chuck, and foundation before extraction when the column extraction method is carried out using the column extraction system shown in Figure 1, and Figure 2(b) is a perspective view showing the column, chuck, and foundation after extraction. [Figure 3] Figure 3 is a side view illustrating the process of attaching the chuck to the column using the base unit and mounting jig before the extraction stage. [Figure 4] Figure 4 is a perspective view showing the base unit shown in Figure 3. [Figure 5] Figure 5 is a side view illustrating the process of installing a jack between the chuck and the base unit before the extraction stage. [Figure 6] Figure 6 is an enlarged side view showing the jack shown in Figure 5. [Figure 7] Figure 7 is a side view illustrating the second stage of the extraction process, which involves additional extraction using a hoist, after the first stage of extraction, which involves extraction using a jack, has been completed. [Figure 8]Figure 8 is a side view illustrating three installation methods for the column according to the embodiment shown in Figure 1. Specifically, Figure 8(a) shows a first installation method in which the column is embedded and fixed in a foundation buried in the ground; Figure 8(b) shows a second installation method in which the column is directly embedded and fixed in the ground; and Figure 8(c) shows a third installation method in which the column is embedded and fixed in a foundation buried in the ground, with the enlarged base at its bottom end exposed from the foundation. [Figure 9] Figure 9 is a representative, enlarged perspective view of one of the multiple divisions shown in Figure 1. [Figure 10] Figure 10 is a side cross-sectional view showing the divided body shown in Figure 9. [Figure 11] Figure 11(a) is a partial side cross-sectional view illustrating the behavior of the outer frame in response to an eccentric load when the outer frame of the chuck is a single-piece type, as a comparative example, and Figure 11(b) is a partial side cross-sectional view illustrating the behavior of the outer frame in response to an eccentric load when the outer frame of the chuck is a laminated type, as an example. [Figure 12] Figure 12 is a magnified partial plan view showing the large plate, one of several plates that make up the stacked segmented body shown in Figure 9, along with the other three segmented bodies assembled to it. [Figure 13] Figure 13 is a magnified plan view showing the smallest plate, one of several plates that make up the stacked segmented body shown in Figure 9, along with the other three segmented bodies attached to it. [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 illustrating a different arc shape from the arc shape of the small plate shown in Figure 14(a). [Figure 15]Figure 15(a) is a plan view showing one of the multiple deep grooves in the large plate shown in Figure 12 and one of the multiple shallow grooves in the small plate shown in Figure 13, corresponding to the one deep groove, as viewed from directly above the laminate shown in Figure 9. Figure 15(b) is a front view showing the multiple plates having these deep and shallow grooves. Figure 15(c) is a side cross-sectional view showing the multiple plates having these deep and shallow grooves. Figure 15(d) is a cross-sectional view showing how the string-like body shown in Figure 1 is contained within the shallow groove in a state where it has been elastically crushed by compression from the columnar body. [Figure 16] Figure 16 is a magnified perspective view of the string-like structure shown in Figure 1. [Figure 17] Figures 17(a) and (b) are cross-sectional views showing an example of the contact layer structure shown in Figure 1, in which multiple string-like bodies, each having a circular cross-section, are arranged as multiple discrete bodies discretely around the circumferential direction of the column, and are aligned along a virtual cylindrical surface concentric with the column. Figures 17(c) and (d) are cross-sectional views showing another example, in which multiple string-like bodies, each having an oval cross-section, are arranged as multiple discrete bodies discretely around the circumferential direction of the column, and are aligned along a virtual cylindrical surface concentric with the column. Figure 17(e) is yet another example, a cross-sectional view showing a structure in which a continuous cylindrical body (sleeve) around the circumferential direction of the column extends axially along a virtual cylindrical surface concentric with the column. [Figure 18] Figure 18(a) is a plan view showing the first circumferential clamping section used for multiple clamping positions A in Figure 12, among the clamping mechanisms shown in Figure 1, and Figure 18(b) is a side view. [Figure 19] Figure 19(a) is a plan view showing the second circumferential clamping section used for multiple clamping positions B in Figure 12, among the clamping mechanisms shown in Figure 1, and Figure 19(b) is a side view. [Figure 20] Figure 20(a) is a plan view showing a chuck suitable for a rectangular prism or rectangular tube as another example of a columnar body, and Figure 20(b) is a plan view showing an enlarged view of the contact layer shown in Figure 20(a). [Figure 21] Figure 21 is a process diagram showing an example of a method for extracting a column using the column extraction system shown in Figure 1. [Figure 22] Figure 22 is a graph that conceptually represents an example of the trend in the temporal changes of the lifting force of a jack during the jacking operation process when implementing the column extraction method shown in Figure 21. [Figure 23] Figure 23 is a perspective view showing an example of a demolition site where there is an obstacle near the installed column, resulting in insufficient clearance to attach the chuck to the column. [Figure 24] Figure 24 is a perspective view showing an example of an asymmetric hinge assembly chuck that can be attached to a column at the demolition site shown in Figure 23. [Modes for carrying out the invention]

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

[0092] Figure 1 shows an exploded perspective view of a column extraction system 10 (an example of a "longitudinal member extraction system," hereinafter referred to as the "system") 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 (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 remove an existing column 12 that is embedded in a foundation 14 (for example, made of concrete, mortar, or a material containing cement as its main component) buried in the ground, by pulling it out from the foundation 14 while leaving the foundation 14 in the ground.

[0096] <<Basic System Configuration>>

[0097] As shown in Figures 1 and 3-7, the system 10 includes a chuck 20 for non-invasively gripping the column 12 in a full-circumference elastic clamping manner, a mounting jig 22 for assisting in the work of attaching the chuck 20 to the column 12, a base unit 24 for preventing the base 14 from rising together with the column 12 during the extraction of the column 12, and a jack 26 for applying axial force to the column 12 via the chuck 20 to pull the column 12 away from the base 14.

[0098] The system 10 further includes a hoist 30 that applies additional axial force to the column 12 via a chuck 20 to pull the column 12 out of the foundation 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 Figures 1, 5, and 11, the load acting on the chuck 20 from the outside to pull out the column 12 is a concentrated eccentric load acting in a straight line offset from the axis of the column 12.

[0100] <<Multiple tasks to be accomplished by the system>>

[0101] 1. Non-destructive extraction work and reduction of vibration and noise.

[0102] In this embodiment, the column 12 is pulled out from the foundation 14 without using heavy machinery such as a small crane for the pulling operation, nor without needing to destroy the foundation 14 using vibrating tools or the like. Furthermore, the column 12 is pulled out from the foundation 14 without applying any impact load to the column 12. As a result, the pulling operation and the associated equipment removal operation are performed non-destructively, with low vibration and noise to avoid disturbing nearby residents.

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

[0104] In this embodiment, the column 12 is removed 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 necessary for the work is designed to be disassembled and assembled, reducing the space occupied in transport vehicles during loading and unloading, and thus facilitating these operations. This reduces the overall labor required for removal work, including the removal operation.

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

[0106] In this embodiment, the column 12 is pulled out without using special or large-scale equipment, for example, by using a handheld manual lifting machine, lifting machine, or pushing machine (for example, a manual jack 26 or 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, as well as reduce work costs.

[0107] 4. Reuse of the extracted columns

[0108] In this embodiment, the column 12 is removed non-invasively using the chuck 20, that is, in a manner that does not leave irreparable marks such as indentations on the column 12 after removal. Because the column 12 is removed non-invasively, the same column 12 can be reused at another site without additional repairs, enabling efficient use of resources and reducing equipment costs at the other site.

[0109] <<Basic structure of a zipper>>

[0110] <Basic principle>

[0111] In general terms, the chuck 20 is elastically and non-invasively attached to the column 12 in a detachable manner in order to quasi-statically apply at least an axial force among the axial force and rotational force to the column 12 for the purpose of pulling the existing column 12 out of its installation location (the foundation 14 in the example shown in the figure).

[0112] <Contact layer>

[0113] The chuck 20 has a cylindrical contact layer 40 (which will be described in detail later with reference to Figures 16 and 17) that is elastic at least in the radial direction (having at least the former of radial elasticity (compressive elasticity) and longitudinal elasticity (bending elasticity)) and has a soft material at least on its surface. When the columnar body 12 is a cylindrical body, this "cylindrical contact layer" is configured as a cylindrical contact surface or cylindrical contact surface.

[0114] The chuck 20 is configured to elastically compress and contact the outer surface of the column 12 via its contact layer 40, such that the contact layer 40 substantially surrounds the outer surface of the column 12 (or partially or locally surrounds it in an area shorter than one full circumference).

[0115] As a result, the chuck 20 is configured to grip the column 12 non-invasively by tightening it within its elastic range, so as not to leave any substantial indentations on its outer surface. Therefore, the chuck 20 can be referred to as a "full-circumference elastic clamping chuck".

[0116] <Outer frame>

[0117] The chuck 20 further includes an outer frame 50 (which will be explained in detail later with reference to Figures 9-15) that holds the contact layer 40 in a position that supports it from behind.

[0118] The outer frame 50 is divided into a plurality of segments 52 arranged in the circumferential direction of the column 12. Each segment 52 is composed of a stack of multiple plates. These plates are consistent with each other in terms of thickness and material, but alternatively, they may be configured to have different thicknesses or materials depending on their axial position, for example.

[0119] <Clamping mechanism>

[0120] In order to assemble these divided parts 52 in a gripping state in which the chuck 20 grips the column 12, the chuck 20 is equipped with a clamping mechanism 80 (which will be described in detail later with reference to Figures 18 and 19) that connects the divided parts 52 detachably in the circumferential direction at multiple positions in a plan view.

[0121] <<Basic Features of Chuck>>

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

[0123] 1. Measures to increase the surface friction coefficient of the contact layer 40

[0124] The contact layer 40 uses a soft material as its surface material (for example, the material of the coating layer 42 described later). This soft material includes an elastic body, synthetic resin, elastomer, or rubber.

[0125] 2. Multiple optional measures to increase the contact area between the column 12 and the contact layer 40.

[0126] (1) The contact layer 40 has higher compressive deformation characteristics than when it is made of a metal part, thereby increasing the radial shape conformability of the contact layer 40 to the outer surface of the column 12. For example, the contact layer 40 is made of a soft material that is easily crushed and flattened by the radial force applied from the outer frame 50.

[0127] (2) The contact layer 40 has higher bending deformation characteristics than when it is made of a metal part, thereby increasing the axial shape-following ability of the contact layer 40 to the outer surface of the column 12. For example, the contact layer 40 is made of 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-elasticity deformation portion that is easily elastically deformed radially in response to radial forces (for example, a small plate 54 described later as a narrow plate) and a high-elasticity deformation portion that is difficult to elastically deform radially in response to radial forces (for example, a large plate 56 described later as a wide plate), each positioned to support the contact layer 40 from behind and at different axial positions 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 (for example, a plurality of longitudinal grooves 58 described later) that contacts the contact layer 40 from behind and accommodates it. The support surface has a first partial support surface (for example, a shallow groove 60 described later) corresponding to the low elastic deformation portion and a second partial support surface (for example, a deep groove 62 described later) corresponding to the high elastic deformation portion. Both the shallow groove 60 and the deep groove 62 have distal portions 64 and 66 that are furthest from the contact layer 40.

[0130] As a result, the portion of the contact layer 40 corresponding to the low-elasticity deformation portion experiences greater radial compression in the compressed state than the portion corresponding to the high-elasticity deformation portion. This configuration also increases the amount of circumferential flattening and crushing, thereby increasing the contact area between the column 12 and the contact layer 40.

[0131] 3. Multiple 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 in the circumferential direction of the column 12, the chuck 20 further includes a first force conversion mechanism that converts a portion of the clamping force acting on the plurality of segments 52 when the plurality of segments 52 are connected to each other and clamped to the column 12 into a radial force and applies it to the contact layer 40.

[0133] The first force conversion mechanism includes an oblique member (the second circumferential clamping section, described later) that extends in a direction inclined with respect to the tangential direction at clamping position B within the clamping mechanism 80. This oblique member converts a portion of the clamping force acting on the multiple divided bodies 52 when they are connected to each other and clamped to the column 12 into a radial force. As a result, the resistance force acting on the contact layer 40 by the outer frame 50 is equalized in the circumferential direction of the contact layer 40, and it is expected that the sum of the resistance forces in the circumferential direction will increase.

[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, that is, as a laminate in which multiple plates 54, 56 extending in a direction transverse to the column 12 are stacked in the axial direction of the column 12, such that sliding and tilting motion of the individual plates is permitted.

[0137] When the eccentric load is applied to the laminate, sliding deformation and tilting occur in which the inner end faces of each of the multiple plates 54, 56 fit into the axial region of the contact layer 40. This is presumed to contribute to achieving a state in which the laminate is in contact with the axial region of the contact layer 40 over as long a portion as possible. As a result, even though the eccentric load is applied to the outer frame 50, the resistance force 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, the sum of the resistance forces in the axial direction is expected to increase.

[0138] 4. Measures to increase the durability of the contact layer 40 when a soft material is used as the surface material of the contact layer 40.

[0139] The contact layer 40 employs a double-layer structure in which metal is used as a backing plate to support the soft material from behind.

[0140] 5. Measures to prevent the string-like body 44, described later, from falling unintentionally from the vertical groove 58 of the chuck 20 before tightening.

[0141] At least a portion of the multiple longitudinal grooves 58 includes a depth-changing section in which the depth changes along its length. This depth-changing section is, for example, the portion in which the shallow grooves 60 and deep grooves 62 described later come into contact with each other along the length of the longitudinal groove 58.

[0142] The depth-changing portion acts as a retainer, preventing the corresponding string-like body 44 from detaching axially from at least some of the longitudinal grooves 58.

[0143] The 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 the "first unit") which applies an upward force to the downward face or other part of the chuck 20 in order to pull the column 12 out of the base 14 via the chuck 20.

[0146] The jack 26 employs a manual drive system, but a fluid or motor drive system may be used instead. Furthermore, while the jack 26 employs a hydraulic system for power assist, a lever, screw, motor, compressed air, or a partial or complete combination thereof may be used instead. Additionally, while the jack 26 employs a direct operation system, a remote control system may be used instead.

[0147] Figure 6 shows a side view of the jack 26. A similar jack 26 is disclosed, for example, in Japanese Patent Publication No. 2002-87767.

[0148] The jack 26 has a horizontally extending, generally plate-shaped base 90 and a hollow cylindrical (bottle-shaped with a bottom on the upper side) housing 92 erected on the base 90. A cylinder 94 is placed inside the housing 92, thereby dividing the internal space of the housing 92 into the space inside the cylinder 94 and a tank chamber 96 outside the cylinder.

[0149] A ram 100 is fitted into the internal space of the cylinder 94 in a liquid-tight and slidable manner, thereby forming a hydraulic chamber 102 between the lower end of the ram 100 and the base 90 or housing 92. Both the tank chamber 96 and the hydraulic chamber 102 are filled with a common working fluid (such as oil).

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

[0151] The jack 26 further has a pump 104, which is also mounted on the base 90. A plunger 106 is fitted to the pump 104 in a liquid-tight and slidable manner, and a pressurized chamber 108 is formed between one end of the plunger 106 and the base 90. The pressurized chamber 108 is fluidically 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 direction of the flow of the working fluid.

[0152] The other end of the plunger 106 protrudes from the pump 104. This protruding end is rotatably connected to one end of a socket 114 (e.g., a sleeve for a handle) which is pivotably connected around 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 detachably inserted into the socket 114. By repeatedly swinging the lever 116 up and down, the operator pressurizes the hydraulic chamber 102, 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 the maximum contraction position, or lowest position, as shown by the solid line in the figure.

[0155] In contrast, when the lever 116 is operated and the jack 26 is driven, resulting in pressurized hydraulic chamber, the ram 100 can rise to its maximum extension position, or highest position, as shown by the dashed line in the figure. At this time, the ram 100 applies an upward force as lift to the chuck 20 with which it is engaged. The difference between the highest and lowest positions of the ram 100 is the lift height.

[0156] <<Base Unit>>

[0157] As illustrated in Figure 3, the system 10 further includes a base unit 24 (an example of a "displacement restraint") which is placed to at least partially cover the base 14 in order to mechanically prevent the base 14 from lifting out of the soil when the column 12 is pulled out.

[0158] As illustrated in Figure 4, the base unit 24 is configured as a disassembly-type unit so that it can be assembled and disassembled on site. This base unit 24 has a hollow structure, and the column 12 can pass through its central part. This base unit 24 has a base that is placed on the foundation 14 so as to cover the foundation 14 at least partially.

[0159] <<Mounting jig>>

[0160] As illustrated in Figure 3, the system 10 further includes a mounting jig 22 to support the chuck 20 from below before assembly, with the aim of assisting the worker in attaching the chuck 20 to the column 12. The mounting jig 22 has a hollow structure and contacts the upper surface of the base unit 24 on its lower surface, while supporting the lower surface of the chuck 20 on its upper surface.

[0161] The worker uses the mounting jig 22 to provisionally position the chuck 20 relative to the column 12 in both the axial and radial directions. In this position, the worker uses the clamping mechanism 80 (see Figures 1, 18, and 19) to tighten the multiple divided parts 52 together with the column 12, thereby assembling the chuck 20 to the column 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 Figure 7, the system 10 further includes a hoist 30 (or winch) (an example of a "second unit") that applies an additional upward force to the chuck 20 when the jack 26 alone does not have sufficient lifting height to partially detach the column 12 from the foundation 14, but does not allow it to be completely removed.

[0165] The hoist 30, for example, has a chain block and is connected to an eyebolt 124 (see Figure 7) which serves as a connector for the chuck 20 using a chain 120 and a hook 122 attached to its end. By winding up the chain 120, the chuck 20 is lifted up together with the column 12, thereby pulling the column 12 within the foundation 14 and ultimately removing it from the foundation 14.

[0166] The hoist 30 employs a manual drive system, but a motor-driven, hydraulic, or compressed air drive system, or a partial or complete combination thereof, may be used instead. Furthermore, while the hoist 30 employs a direct operation system, a remote control system may be used instead.

[0167] <<Multi-tiered scaffolding>>

[0168] As illustrated in Figure 7, this system 10 further includes multiple levels of scaffolding 32 on which the hoist 30 is installed in order to raise the installation position of the hoist 30. In the figure, the scaffolding 32 shown by a solid line represents the first level of scaffolding 32. To further raise the installation position of the hoist 30, a second level of scaffolding 32 is installed on top of the first level of scaffolding 32, as shown by the dashed line in the figure. Each level of scaffolding 32 is constructed to be assembled and disassembled on site.

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

[0170] <<Outer frame>>

[0171] As shown in Figure 9, a representative enlarged perspective view of one of the multiple divided bodies 52 shown in Figure 1, the outer frame 50 is not constructed as a single block (for example, a metal block) extending in the axial direction of the column 12, but rather as a laminate in which multiple plates 54, 56 extending in a direction transverse to the column 12 are stacked in the axial direction of the column 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 Figure 12) and multiple small plates 54 (see Figure 13). Regardless of type, the periphery of each plate 54, 56 is divided into an inner edge closest to the outer surface of the column 12, an outer edge furthest from it, and a right edge and a left edge located to the right and left of the center of the column 12, respectively.

[0173] As shown in Figures 9 and 10, multiple small plates 54 are divided into three groups by multiple large plates 56, and in each group, multiple stacked small plates 54 are sandwiched between two adjacent large plates 56.

[0174] As shown in Figure 12, multiple through-holes are formed in each of the multiple large plates 56 in order to stack and fasten them in a predetermined relative position. Some of these through-holes are arranged on multiple radial lines (shown as dashed lines in the figure) that extend at equal angles from the center of the chuck 20 so that the fastening force of the multiple divided bodies 52 is equalized in the circumferential direction.

[0175] Some of the aforementioned multiple through holes are formed in each large plate 56 at multiple 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. In addition, one position E is located in the center of the outer edge of each large plate 56.

[0177] Furthermore, for each large plate 56, one position F is located approximately in the center of the right edge of each large plate 56. Also, for each large plate 56, one position G is located approximately in the center of the left edge of each large plate 56, and position G differs from position F in terms of its distance from the center of the column 12. In other words, positions F and G are positioned so that they do not lie on concentric circles.

[0178] Furthermore, for each large plate 56, the two positions H1 are located at both ends of the outer edge of each large plate 56. Similarly, for each large plate 56, the two positions H2 are located at both ends of the outer edge of each large plate 56, but positions H2 differ from positions H1 in terms of their distance from the center of the column 12.

[0179] Furthermore, for each large plate 56, the two positions J are located circumferentially inward of the left pair of positions H1 and H2 and the right pair of positions H1 and H2 on the same large plate 56.

[0180] Specifically, groups consisting of positions H1, H2, and J, located at the three vertices of a triangle that generally forms an equilateral triangle, are arranged on both sides of the outer edge, and these two groups are arranged symmetrically on the same large plate 56 with respect to its centerline (a straight line passing through the central angle position of each large plate 56 (indicated as "center" in the figure) and position E).

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

[0182] As shown in the side cross-sectional view in Figure 10, the large plate 56 and the small plate 54 are fastened together in a stacked state by passing a rod-shaped fastener 130 through a predetermined number of through holes. Examples of the rod-shaped fastener 130 include a shaft (without threads) or a long screw (with threads at least at both ends), and other examples include nuts and eye bolts.

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

[0184] In this case, a spacer 134 (sleeve or collar) is positioned between two adjacent large plates 56, inserted through a rod-shaped fastener 130. This defines 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 clearance") remains between each rod-shaped fastener 130 and each through hole. This thread clearance is approximately 1 mm in diameter and corresponds to, for example, a hole diameter grade of 2 or higher.

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

[0187] As explained above, the outer frame 50 is constructed as a laminate, and a plurality of thin plates 54, 56 are fastened to each other with a relatively large screw gap, thereby forming a laminate that can slide. The effects of this will be examined.

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

[0189] In this comparative example, as in the embodiment described later with reference to Figure (b), eccentric loads act on the outer frame 50 from a pair of jacks 26 facing each other across the column 12, in parallel and both upward. Due to each eccentric load, bending moments act on the outer frame 50 in opposite directions.

[0190] In this comparative example, similar to the embodiment, it is presumed that each bending moment causes radial forces to act on the outer frame 50 in a non-uniform pattern, increasing from the proximal point (contact point (point of force application), lowest point) to the distal point (highest point) of the outer frame 50 relative to the jack 26.

[0191] Under these mechanical conditions, in this comparative example, the outer frame 50 is constructed as a rigid metal block. Therefore, in this comparative example, the outer frame 50 does not deform itself, but tilts (angularly displaces) in response to the bending moment.

[0192] As a result, rigid body displacement (angular displacement, i.e., tilting of the entire rigid body) occurs in the outer frame 50, at its proximal point moving radially outward from the outer surface of the column 12, and at its distal point moving radially inward towards the outer surface of the column 12.

[0193] Therefore, in this comparative example, it is presumed that the chuck 20 is locally lifted away from the outer surface of the column 12 at its proximal point. This would then emphasize the non-uniformity of the distribution pattern of radial forces acting on the outer frame 50.

[0194] As a result, in this comparative example, the resistance force generated in the contact layer 40 is locally reduced at the proximal point, the frictional force between the contact layer 40 and the column 12 is also locally reduced, and consequently, the total axial sum of the resistance forces generated in the contact layer 40 is also reduced.

[0195] In contrast, Figure (b) shows, as an embodiment of the present invention, the results of an analysis of the behavior of the outer frame 50 in response to an eccentric load when the outer frame 50 of the chuck 20 is a laminate that can slide, as shown in a partial side cross-sectional view.

[0196] In this embodiment, when the eccentric load acts on the outer frame 50 as a laminate capable of sliding motion, it is presumed that the bending moment will cause individual sliding motion and tilting of the multiple plates 54, 56. As a result, it is presumed that sliding deformation and tilting will occur throughout the outer frame 50 itself, thereby maintaining the contact layer 40 in a state where its inner surface is in overall axial contact with the outer surface of the column 12.

[0197] As a result, even though the eccentric load acts on the outer frame 50, the reduction in the area of ​​the axial region in which the contact layer 40 contacts the outer surface of the column 12 is suppressed, and the emphasis on the non-uniformity of the distribution pattern of radial forces acting on the outer frame 50 is suppressed. Consequently, it is presumed that the resistance force acting on the contact layer 40 by the outer frame 50 is equalized in the axial direction, thereby increasing the total resistance force.

[0198] <<Contact layer>>

[0199] As shown in Figure 17(a), the contact layer 40 has a structure in which a plurality of string-like bodies 44, each having a circular cross-section, are arranged discretely in the circumferential direction of the columnar body 12 as a plurality of discrete bodies, aligned along a virtual cylindrical surface (an example of a "virtual cylindrical surface") concentric with the columnar body 12. As shown in Figure 17(b) and Figure 16, each string-like body 44 includes a core material 46 mainly made of metal and a covering layer 42 (an example of a "surface layer") covering the core material 46, which is mainly made of a soft material. The material constituting the covering layer 42 is an example of a "surface layer material".

[0200] <Contact layer structure>

[0201] An example of each string-like body 44 is a resin-coated wire rope, as shown in Figure 16. This resin-coated wire rope is constructed by having a wire rope as the core material 46, a synthetic resin sleeve as the coating layer 42, and having the surface coated with synthetic resin.

[0202] Here, the "wire rope" is constructed by twisting together multiple strands (small ropes, small blocks) made up of multiple individual wires around a core (steel core, core rope). The material of the "individual wires" is metal, such as stainless steel, tungsten, or titanium alloy. The "core" is also called a fiber core or a metal core. The material that makes up 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 is flexible (bendable). Furthermore, the core material 46 has higher flexibility (ease of compressive deformation in the diametrical direction (e.g., ease of strand collapse and crushing), ease of bending in the direction intersecting the longitudinal direction) as a result of allowing slippage between the multiple individual wires and between the multiple strands.

[0205] Furthermore, both the coating layer 42 and the core material 46, due to the elasticity of their respective materials, return to their original cross-sectional shape (such as a circle) and overall shape (straight line) after unloading (natural state). In addition, the coating layer 42 has higher flexibility (ease of compression deformation in the diametrical direction and ease of bending in directions intersecting the longitudinal direction) than a metal coating 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 coefficient of surface friction than the core material 46, while the core material 46 has higher elastic recovery properties than the coating layer 42 (e.g., elastic recovery in the bending direction, elastic recovery in the compression direction, etc.).

[0207] In this embodiment, each wire rope is end-finished at at least one end. Specifically, a sleeve or clip, which is a pre-made fitting, is crimped onto the rope end. Because this pre-made fitting is present at the end, when each wire rope is held on the inner surface of the outer frame 50 as shown in Figure 1, it is prevented from falling due to its own weight.

[0208] <<Outer frame>>

[0209] <Laminate 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-elasticity deformation part that is easily elastically deformed radially against a radial force, and a large plate 56 as a high-elasticity deformation part that is difficult to elastically deform radially against a radial force, each 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-elasticity deformation portion is a small plate 54, which is a narrow plate with a width dimension W1, as shown in Figure 14(a). In contrast, the high-elasticity deformation portion is a large plate 56, which is a wide plate with a width dimension W2 that is longer than the width dimension W1, as shown in the same figure.

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

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

[0214] In this example, compared to the case where multiple shallow grooves 60 are arranged along a perfect arc together with multiple corresponding string-like bodies 44, the radial distance of each string-like body 44 from the center of the column 12 is shortened, and consequently, the amount of radial outward deflection of the corresponding multiple small plates 54 increases.

[0215] As a result, in this example, even if the diameter of the column 12 is the same, a greater repulsive force acts from each small plate 54 to each string-like body 44, thereby increasing the resistance force acting on the contact layer 40 in the radial direction (thickness direction), and consequently increasing the frictional force generated in the contact force. In this way, the effect of amplified frictional force is obtained.

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

[0217] As shown in Figure 1, the outer frame 50 has multiple vertical grooves 58 (an example of "grooves") that contact each of the multiple string-like bodies 44 from behind and accommodate the string-like bodies 44. Each vertical groove 58 is a collection of multiple shallow grooves 60 and multiple deep grooves 62 arranged in a row, as shown in Figure 15(b).

[0218] As illustrated in Figure (d), when each string-like body 44 is compressed by the column 12, it is flattened in the corresponding shallow groove 60, becoming crushed and extending in the circumferential direction. Similarly, although not shown, when each string-like body 44 is compressed by the column 12, it is also flattened in the corresponding deep groove 62, becoming crushed and extending in the circumferential direction, but to a lesser extent than in the shallow groove 60.

[0219] Each vertical groove 58 (shallow groove 60 and deep groove 62) has a cross-sectional shape that forms a partial circle opening at the inner edge of the outer frame 50 (a cross-sectional shape that substantially complements the cross-sectional shape of the string-like body 44), as shown in Figure (a). The multiple vertical grooves 58 are formed by arranging multiple shallow grooves 60 (an example of a "first partial groove") formed on multiple small plates 54 and multiple deep grooves 62 (an example of a "second partial groove") formed on multiple large plates 56, in a single line in the vertical direction at the same phase.

[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 relationship between the two can be expressed by the inequality Q1 > Q2. Therefore, as shown in Figure (a), the deep groove 62 is configured to have a cross-sectional shape that forms a subcircle larger than the cross-sectional shape of the shallow groove 60.

[0221] As shown in Figures 13 and 15(a)-(c), multiple shallow grooves 60 are arranged in a row along the inner edge of each small plate 54. Each shallow groove 60 is generally configured to have a semicircular cross-sectional shape. In contrast, as shown in Figures 12 and 15(a)-(c), multiple deep grooves 62 are arranged in a row along the inner edge of each large plate 56.

[0222] Here, Figure 15(a) is a plan view showing an enlarged view of the laminate shown in Figure 9, with one of the multiple deep grooves 62 in the large plate 56 shown in Figure 12 and one of the multiple shallow grooves 60 in the small plate 54 shown in Figure 13, as viewed from directly above. Figure 15(b) is a front view showing the multiple plates 54 and 56 having these deep grooves 62 and shallow grooves 60. Figure 15(c) is a side cross-sectional view showing the multiple plates 54 and 56 having these deep grooves 62 and shallow grooves 60.

[0223] Both the shallow grooves 60 and the deep grooves 62 have proximal portions 64 and 66 that are closest to the outer surface of the column 12 and distal portions 68 and 70 that are furthest from it.

[0224] The proximal portion 64 of the shallow groove 60 is in roughly the same relative position to the outer surface of the column 12 as the proximal portion 66 of the deep groove 62, but the distal portion 68 of the shallow groove 60 is closer to the outer surface of the column 12 than the distal portion 70 of the deep groove 62.

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

[0226] As a result, an amplified resistance force and thus frictional force is generated between each string-like body 44 and the columnar body 12, and an expanded contact area is formed between each string-like body 44 and the columnar body 12.

[0227] <<Clamping Mechanism>>

[0228] <Basic configuration>

[0229] The clamping mechanism 80 includes a circumferential clamping section 82 (a first circumferential clamping section 84 and a second circumferential clamping section 86) for connecting and joining multiple divided bodies 52 in the circumferential direction, and an axial clamping section 88 for connecting and joining multiple plates 54, 56 in the axial direction for each divided body 52.

[0230] <Circumferential clamping section>

[0231] As illustrated in Figure 12, the circumferential clamping portion 82 is configured such that, for example, at clamping positions A and B, a long screw or shaft acting as a rod-shaped fastener tightens two adjacent divided bodies 52 in a circumferential or oblique direction.

[0232] Figure 18(a) shows a plan view of the first circumferential clamping section 84 used at multiple clamping positions A, and Figure 18(b) shows a side view of the same section.

[0233] The first circumferential clamp portion 84 includes a first long screw 140 that passes through clamp positions H1 and H2, respectively, and a second long screw 142 that passes through clamp position J. Furthermore, it includes two sets of eye bolts 144, nuts 146, and plates 148 that connect the long screws 140 and 142 in the circumferential direction, arranged in parallel in the axial direction. The second long screw 142 at position J passes through the eye portion of the eye bolt 144. The plate 148 is positioned 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, respectively.

[0234] Figure 19(a) shows a plan view of the second circumferential clamping section 86 used at multiple clamping positions B, and Figure 19(b) shows a side view of the same section.

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

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

[0237] As shown in Figure 12, at clamp position B, the second eyebolt 164 extends in a direction that intersects both the radial and circumferential directions. This second eyebolt 164 acts as the aforementioned oblique member that extends in a direction inclined with respect to the tangential direction at clamp position B.

[0238] As a result of such dytometry being applied to the second circumferential clamp portion 86, a radial force acts on the two adjacent segmented bodies 52 in addition to the circumferential force, thanks to this second circumferential clamp portion 86. This means that a portion of the axial force of the second eyebolt 164, i.e., the clamping force on those segmented bodies 52, is converted into a radial force on the contact layer 40.

[0239] <Axial clamping section>

[0240] As illustrated in Figure 10, the axial clamping section 88 is configured such that, for each segmented body 52, for example at clamping positions D and E, a rod-shaped fastener 130, which is a long screw or shaft, penetrates only all of the plates 54, 56 or multiple large plates 56 to tighten those members.

[0241] Specifically, Figure 10 shows, as described above, how all plates 54 and 56 are tightened by long screws 130 that pass through them at clamp position D, and how multiple large plates 56 are tightened by long screws 130 at clamp position E, with a predetermined gap between them ensured by spacers 134.

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

[0243] <Overview>

[0244] Figure 21 shows an example of a process diagram illustrating how to extract the column 12 using the aforementioned system 10.

[0245] According to this column extraction method, the column 12 is gradually extracted from the foundation 14, as shown in Figures 5 and 7.

[0246] In other words, as shown in Figure 5, this column extraction method is configured to include the steps of: driving the jack 26 to apply an axial force to the chuck 20 in a direction that separates it from the foundation 14 together with the column 12, not as an impact force but as a quasi-static force, thereby partially or completely extracting the column 12 from the foundation 14; and, if the column 12 cannot be extracted from the foundation 14 by using only the jack 26, driving the hoist 30 as shown in Figure 7 to additionally apply a quasi-static axial force to the chuck 20 in a direction that separates it from the foundation 14 together with the column 12, thereby completely extracting the column 12 from the foundation 14.

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

[0248] A plurality of facilities required for the extraction operation (such as the base unit 24 shown in FIGS. 3 and 4, the mounting jig 22 shown in FIG. 3, the chuck 20 shown in the same figure, the jack 26 shown in FIG. 5, the hoist 30 shown in FIG. 7, the chain 120 shown in the same figure, the scaffold 32 shown in the same figure, etc.) are carried into a transport vehicle such as a truck in a disassembled state at their storage locations and transported to the destination site (for example, a used parking lot as a location where equipment removal is requested).

[0249] When those facilities arrive at the site, they are assembled by the operator.

[0250] 2. Second Step: Extraction Operation by Jack 26

[0251] <Overview>

[0252] This step mainly involves applying an axial force in the direction of separating the chuck 20 from the base portion 14 together with the column body 12 to the chuck 20 as a quasi-static force (quasi-static load) rather than an impact force (impact load) by driving the jack 26, thereby pulling out the column body 12 from the base portion 14.

[0253] Here, the "quasi-static force (quasi-static load)" is defined as not being a static load in that its magnitude changes with time, and excluding the impact load among dynamic loads. Specifically, the "quasi-static force (quasi-static load)" is, for example, a load whose magnitude changes with time at a speed lower than the impact load, and is also a load that transitions through a gradually increasing phase, a gradually decreasing phase, a holding phase, etc.

[0254] <Preparation Work>

[0255] Prior to the extraction operation, a plurality of required facilities (such as the base unit 24, the mounting jig 22, the chuck 20, the jack 26, etc.) are assembled at the 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 arranged integrally.

[0257] Specifically, in this preparation stage, as shown in Figure 4, first, in order to prevent the foundation 14 from rising as the column 12 rises, a hollow base unit 24 (an example of a "displacement restraint") is installed to cover the foundation 14. Figure 5 shows an example of the base unit 24 in a perspective view. In this example, the column 12 penetrates the central part of the base unit 24.

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

[0259] Next, the chuck 20 is placed on the upper surface of the mounting jig 22, before its assembly is complete and while the column 12 is accessible from both sides in its diametrical direction. In this state, the multiple segments 52 are tightened 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] Subsequently, multiple jacks 26 are placed on the upper surface of the base plate, facing each other so as to sandwich the column 12 from both sides in its diametrical direction. At this time, each jack 26 is in its maximum retracted position, and normally, for the 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] In the plan view of Figure 12, as indicated by jack 26 (load position, jack position) C, each jack 26 makes local contact with the lower surface of the chuck 20 at an eccentric position from the center of the column 12 at the upper end of its ram 100.

[0262] Once the installation of each jack 26 is complete, the mounting jig 22 is removed from the column 12, as shown in Figure 5. This completes the preparation for the pull-in operation using the jacks 26.

[0263] <Main task>

[0264] The lever 116 of the jack 26 is repeatedly swung by the worker. This increases the lifting force of the jack 26, and at this time, as shown in Figures 5 and 11, this lifting force acts as a concentrated eccentric load from the jack 26 to the chuck 20.

[0265] The jacks 26 are positioned opposite each other on each side of the column 12, with one jack 26 on each side, and these two jacks 26 are operated by one or two workers so that their respective lifting forces rise almost synchronously. The combined action of these jacks 26 applies an axial force to the column 12 that pulls it away from the foundation 14. Due to the opposing arrangement and synchronous operation of the multiple jacks 26, the opposing bending moments caused by the eccentric loads of each jack 26 tend to cancel each other out in the column 12.

[0266] Before withdrawal, there is a gap between the upper surface of the ram 100 of the jack 26 and the lower surface of the chuck 20. When the operator drives the jack 26, its lifting force increases to a level that overcomes the weight and frictional force of the ram 100, as shown in the graph in Figure 22, until the gap disappears. Eventually, the jack 26 and the chuck 20 come into contact at the jack position C in Figure 12.

[0267] Incidentally, before extraction, the column 12 and the foundation 14 are integrated at their surfaces. Therefore, in order to extract the column 12 from the foundation 14, it is necessary to apply a force to the column 12 that overcomes the adhesive force between them (e.g., bonding force, jointing force, etc.). This force is necessary to separate and detach the column 12 from the foundation 14. Furthermore, it is presumed that it is also necessary to apply a force to the column 12 that overcomes the maximum static friction coefficient between the column 12 and the foundation 14.

[0268] Here, the force required for the pull-out is, for example, the force that resists the column 12 being pulled out from the foundation 14, that is, the 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 the pull-out also includes the force that overcomes the sum of the weight of the column 12 and the weight of the chuck 20.

[0269] Therefore, after the jack 26 and chuck 20 come into contact, if the worker continues to drive the jack 26, the lifting force of the jack 26 will increase, but until it reaches the pull-out resistance force, neither the chuck 20 nor the column 12 will rise and will remain stationary. In this phase, even if the lever 116 of the jack 26 is repeatedly swung by the worker and the lifting force of the jack 26 increases, the ram 100 will not rise, and instead, the working fluid inside the jack 26 will be compressed.

[0270] Eventually, when the lifting force of the jack 26 overcomes the pulling resistance, both the chuck 20 and the column 12 begin to rise. At this point, the force required for this rise is sufficient to overcome the coefficient of dynamic friction between them, plus the sum of the weight of the column 12 and the weight of the chuck 20, so the lifting force of the jack 26 decreases. Subsequently, both the chuck 20 and the column 12 rise by the amount the worker drives the jack 26.

[0271] Eventually, the ram 100 of the jack 26 reaches its highest point. At this point, the column 12 still has a portion remaining within the foundation 14, and the column 12 has not been completely pulled out of the foundation 14. This is because the lifting height of the jack 26 is lower than the initial embedment depth of the column 12 within the foundation 14.

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

[0273] <Overview>

[0274] This step is mainly about the process of completely pulling out the column body 12 from the foundation part 14. When the column body 12 cannot be completely pulled out from the foundation part 14 only by using the jack 26, as shown in Fig. 7, the operator drives the hoist 30 to quasi-statically and additionally apply an axial force in the direction of separating the chuck 20 from the foundation part 14 together with the column body 12, thereby completely pulling out the column body 12 from the foundation part 14.

[0275] <Preparation work>

[0276] As shown in Fig. 7, the operator installs the first-stage scaffold 32 at a predetermined position relative to the column body 12. The hoist 30 is suspended from the upper plate of the scaffold 32. A chain 120 hangs down from the hoist 30, and a hook 122 is at the tip of the chain 120. The hook 122 is connected to the eye bolt 124 as a connector of the chuck 20.

[0277] <This operation>

[0278] After that, the operator drives the hoist 30 to wind up the chain 120, thereby pulling up the chuck 20 together with the column body 12. As a result, the column body 12 is additionally pulled up from the foundation part 14, and finally, the column body 12 is completely pulled out from the foundation part 14.

[0279] However, if the first-stage scaffold 32 is not sufficient, as shown by the two-dot chain line in Fig. 7, the second-stage scaffold 32 is stacked, and again, the chuck 20 is pulled up together with the column body 12 by the hoist 30.

[0280] As shown in Fig. 2(b), at the stage after pulling out, while the column body 12 and the chuck 20 are integrally arranged, the column body 12 is arranged separately upward from the foundation part 14. After pulling out, a cylindrical hole (hereinafter referred to as "trace hole") having substantially the same diameter as the column body 12 appears in the foundation part 14 as a trace where the column body 12 is pulled out from there.

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

[0282] 4. Dismantling and removal of equipment

[0283] Once the column 12 is completely removed from the foundation 14 as described above, the removed column 12 is placed on the ground by the worker. Furthermore, the chuck 20 is dismantled by the worker and removed from the column 12. Finally, the base unit 24, which was used as equipment for the removal operation, is removed from the foundation 14 by the worker.

[0284] Furthermore, the workers dismantle other equipment as well. Once the dismantling work is complete for all equipment, the workers load the equipment onto the transport vehicle and return it to the storage location.

[0285] <<Example Test>>

[0286] Here, the specific specifications of the column 12, chuck 20, and jack 26 and hoist 30 as axial force applying devices will be described based on an example of actual testing conducted by the inventor.

[0287] <Specifications of the column>

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

[0289] <Specifications of the foundation>

[0290] Concrete

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

[0292] Model number: PVC3-5-200-1M (JIS G 3525 1998) Manufactured by Nikko Steel Co., Ltd. Structure: "7 strands, 6 core fibers": It has 6 strands, each strand consisting of 7 individual wires, with a fiber core at the center of multiple strands. Core material: stranded wire Coating layer: PVC (flexible vinyl) Rope diameter (core diameter): 3mm Coating outer diameter (apparent diameter): 5mm

[0293] <Jack specifications>

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

[0295] In this test example, as with the previously described embodiment, two jacks 26 were used in parallel arrangement for one column 12, resulting in a total maximum lifting capacity of 8 tons, which is equivalent to twice the maximum lifting capacity of a single jack 26.

[0296] <Hoist Specifications>

[0297] Rated load (maximum lifting capacity): 0.3 tons Lifting height: 2.5m

[0298] In this test example, as with the previously described embodiment, one hoist 30 was used for each column 12, so the final maximum lifting capacity remained at 0.3 tons.

[0299] <Test Results>

[0300] The inventors prototyped the system 10 using equipment having those specifications and experimentally performed extraction operations on the column 12 and foundation 14 having the above specifications at the site.

[0301] As a result, the inventors recognized that, as described above, the lifting force of the jack 26 during the extraction process showed the temporal progression illustrated in Figure 22. Furthermore, the inventors confirmed that there were no traces of the chuck 20 on the part of the column 12 where it had been attached after extraction, and that, as described above, there were no harmful traces on the foundation 14 either.

[0302] Therefore, the inventors recognized that the removed column 12 could be reused elsewhere without substantial repair. Furthermore, the inventors recognized that if the foundation 14 was backfilled on-site without excavating the soil, it might have been possible to avoid removing the foundation 14 from the soil.

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

[0304] <<Other effects of this embodiment>>

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

[0306] Although the column 12 is a rigid body, the contact between the column 12 and the contact layer 40 appears as a rigid-soft contact, and this rigid-soft contact improves the fit of the surface of the contact layer 40 to the surface of the column 12 compared to contact between rigid bodies.

[0307] <<Various Modifications of This Embodiment>>

[0308] Although several exemplary embodiments of the present invention have been described above, the present invention can be implemented in other forms.

[0309] <Variations in 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 section, and the chuck 20 is configured to be attached to that straight section.

[0311] In contrast, if the longitudinal member has a curved portion, the chuck 20 may be configured to be attached to that curved portion. Alternatively, if the longitudinal member has an angled portion, the chuck 20 may be configured to be attached to that angled portion.

[0312] According to this embodiment, as described above, the contact between the longitudinal member and the chuck 20 becomes a rigid-to-flexible contact when the longitudinal member is a rigid body, and even when the chuck 20 has a non-simple shape that is not a straight line, such as a curved portion or an angled portion, it is easy to fit that shape.

[0313] <Modified cross-sectional shape of a 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 carried out in a manner in which a longitudinal member having a hollow structure and an open cross-sectional shape (for example, a pipe with vertical slits) is gripped by the chuck 20.

[0315] Furthermore, in this embodiment, the column 12 is a longitudinal member having a hollow structure and a continuous outer surface in the circumferential direction. However, the present invention may also be carried out in a manner in which a longitudinal member having a hollow structure and an outer surface having discontinuous portions in the circumferential direction is gripped by the chuck 20.

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

[0317] <Modified versions of column installation methods>

[0318] Incidentally, as shown in Figure 8, there are at least three exemplary installation methods for the column 12 that can be removed (extracted) according to the present invention.

[0319] Specifically, Figure (a) shows a first installation method in which the column 12 is embedded and fixed in a foundation 14 buried in the ground. In this embodiment, the column 12 is configured as a longitudinal member 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 while the foundation 14 remains in the soil.

[0320] Figure (b) also shows a second installation method in which the column 12 is directly embedded and fixed in the ground. The present invention may also be implemented in which the chuck 20 is attached to a longitudinal member installed according to the second installation method. In this case, the column 12 as a longitudinal member will be pulled out of the soil by itself.

[0321] Figure (c) also shows a third installation method in which a column 12 is embedded in the ground and fixed in a state in which an enlarged base 16 (such as a member having a shape that protrudes from the cross-sectional shape of the main body of the column 12) is joined to the bottom end of the column 12 in a state in which it is exposed from the ground.

[0322] Furthermore, the present invention may be implemented in a manner in which the chuck 20 is attached to a longitudinal member installed according to a third installation method. In this case, the column 12 (to which the enlarged base 16 is attached) as a longitudinal member will be pulled out of the soil together with the foundation 14.

[0323] <Variations of the contact layer structure>

[0324] In this embodiment, as described above, the contact layer 40 has a structure in which a plurality of string-like bodies 44, each having a circular cross-section, are arranged discretely in the circumferential direction of the columnar body 12 as a plurality of discrete bodies, aligned along a virtual cylindrical surface concentric with the columnar body 12, as shown in Figures 17(a) and (b).

[0325] Alternatively, as shown in Figures (c) and (d), the present invention may be implemented in a manner in which the contact layer 40 has a structure in which, for example, a plurality of string-like bodies 44, each having an oval cross-section, are arranged discretely in the circumferential direction of the columnar body 12 as a plurality of discrete bodies, aligned along a virtual cylindrical surface concentric with the columnar body 12.

[0326] Furthermore, as shown in Figure (e), the present invention may be implemented in a configuration in which the contact layer 40 has a structure in which a single cylindrical body (such as a sleeve) continuous in the circumferential direction of the column 12 extends axially along a virtual cylindrical surface concentric with the column 12.

[0327] <Modified arrangement of string-like structures>

[0328] In this embodiment, multiple string-like bodies 44 are arranged to extend parallel to the axis of a virtual cylindrical surface that is substantially concentric with the columnar body 12.

[0329] In contrast, the present invention may be implemented in a manner in which the string-like bodies 44 are arranged to extend in parallel in a spiral manner along the virtual cylindrical surface and around its axis. According to this embodiment, it becomes easy to reduce the number of string-like bodies 44 required to achieve the same contact area between the string-like bodies 44 and the columnar body 12.

[0330] <Modified cross-sectional shape of a column>

[0331] In this embodiment, the column 12 is a cylindrical body (solid), a cylindrical body, or a round pipe (hollow). However, instead of these, the column 12 may be constructed as a rectangular prism (solid), a rectangular tube, or a rectangular pipe (hollow), as illustrated in Figure 20.

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

[0333] <Modified example of a drive mechanism for raising the chuck>

[0334] In this embodiment, during the initial stage of the column 12 extraction process, when the resistance force to extract the column 12 is high, a jack 26 (high output, low lifting height or high output, short stroke) is used as the first drive source, and the chuck 20 is raised by pushing up the chuck 20 with the jack 26.

[0335] Subsequently, in the later stage when the pull-out resistance has decreased, a hoist 30 (low power, high lift height or low power, long stroke) is used as a second drive source in place of the jack 26, and the chuck 20 is raised by lifting it with the hoist 30.

[0336] In other words, in this embodiment, (1) The circumstances that 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 magnitude 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.) (two types of drive sources that have a complementary relationship in terms of performance, where each compensates for the other's shortcomings), (2) The circumstances that the size of the load and the length of the lift required for extraction differ depending on the stage of the extraction process, specifically, for example, that in the initial stage a large load is required but the lift may be short, while in the subsequent stage a long lift may be short. In light of this, multiple types of drive sources are used depending on the required load size and maximum stroke length, that is, depending on the stage of the extraction process.

[0337] In contrast, if a single type of drive source is used that can achieve the maximum load and stroke required at each stage of the extraction process (for example, the initial stage and the subsequent stage) throughout the entire extraction process, the extraction of the column 12 can be completed by using only one type of drive source throughout the entire extraction process.

[0338] For example, the present invention may be implemented in a manner in which a high-performance lifting machine such as a hoist 30 or a crane is used as the drive source, and the chuck 20 is lifted throughout the entire process by the drive source, thereby pulling out the column 12 without switching the drive source.

[0339] In this embodiment, prior to pulling out the column 12, the worker brings the multiple segments 52 of the chuck 20 close to the column 12 in a horizontal plane in order to attach the chuck 20 to the column 12. Therefore, in order to pull out the column 12 using the chuck 20, space or gap is required for each segment 52 to move horizontally.

[0340] Therefore, in demolition sites where obstacles (such as walls or nearby buildings) as illustrated in Figure 23 exist near the column 12, it is difficult or impossible for workers to attach the chuck 20 to the column 12.

[0341] <Another embodiment>

[0342] To solve this problem, the chuck 20 may be configured as, for example, an asymmetric hinge assembly chuck 170 as illustrated in Figure 24.

[0343] This chuck 170 has an asymmetrical shape such that, for example, in a plan view, it is narrower or smaller on the back side where the gap is narrower because the column 12 is closer to the obstacle, and wider or larger on the front side where the gap is wider because the column 12 is further away from the obstacle.

[0344] Furthermore, the chuck 170 is configured to include, for example, a narrow base end 172 located on the rear side, a pair of arm portions 174, 174 connected thereto by a hinge 173 which are capable of gripping the column 12 from both sides in the diametrical direction, and a sliding portion 176 that is slidable between the arm portions 174, 174 and relative to the arm portions 174, 174.

[0345] Furthermore, the chuck 170 has multiple partial cylindrical surfaces, each having one circumferential surface divided into, for example, the inner surface of the base end 172, the inner surfaces of the pair of arm portions 174, 174, and the inner surface of the slide portion 176. Contact layers 178, similar to the contact layer 40 described above, are formed on these partial cylindrical surfaces.

[0346] Furthermore, in this example, the worker positions the chuck 170 in an extended state so that it passes behind the column 12.

[0347] Subsequently, the worker brings the pair of arm portions 174, 174 closer together to compress the column 12 in one diametrical direction U, and also brings the base end portion 172 and the slide portion 176 closer together to compress the column 12 in another diametrical direction V perpendicular to the diametrical direction U, thereby elastically and non-invasively pressing the chuck 170 all around the column 12.

[0348] In this example, the base portion 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 pivotably connected to the base portion on a plane (for example, a horizontal plane), and which supports the contact layer 178 from behind.

[0349] It should be added that, while it has been pointed out that in some of the embodiments illustrated above, high frictional force and non-invasive contact can be achieved simultaneously in the chuck, if reuse of the extracted column 12 is not required, non-invasive contact in the chuck does not need to be achieved.

[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 implemented in various other forms with modifications and improvements based on the knowledge of those skilled in the art, starting with the embodiments described in the [Summary of the Invention] section above.

Claims

1. A chuck that is detachably attached to an existing longitudinal member in order to pull the longitudinal member out of its installation location, A cylindrical contact layer having elasticity at least in the radial direction and capable of contacting the outer surface of the longitudinal member in a manner that completely or partially surrounds the outer surface of the longitudinal member, A lever mechanism in which a pair of levers are connected to a base end so as to be swingable on a plane, with each lever extending from the base end, wherein the pair of levers compress the outer surface of the longitudinal member from both sides in the diametrical direction with their respective inner surfaces, and the pair of levers support the contact layer from behind with their respective inner surfaces, thereby enabling the contact layer to tighten the longitudinal member within its elastic range. A chuck for extracting longitudinal members, including a chuck.

2. The longitudinal member extraction chuck according to claim 1, wherein the pair of levers are a pair of arm portions hinged to the base end and capable of gripping the outer circumferential surface of the longitudinal member from both sides in the diametrical direction via the contact layer.

3. Furthermore, the pair of arm portions includes a sliding portion that is slidable relative to those arm portions, The longitudinal member extraction chuck according to claim 2, wherein the inner surface of the base end, the inner surfaces of each of the pair of arm portions, and the inner surface of the slide portion each have a plurality of partial cylindrical surfaces, each having a circumferential surface divided into several parts, and the contact layer is supported on these partial cylindrical surfaces.

4. The longitudinal member extraction chuck according to any one of claims 1 to 3, wherein the contact layer has a soft material in at least the surface layer.

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