Tension jack hanging tool, tension jack support base, and tension method

Abstract

To provide a tension jack hanging tool, a tension jack support base and a tension method, applicable even in a construction site having an overhead clearance limit, and capable of maintaining a once adjusted angle and position regardless of operation of a jack.SOLUTION: A tension jack hanging tool 1 for hanging and supporting a tension jack J1 that expands and contracts according to a tension operation includes a portal frame 2 including a base 3 that can be placed on a plane, a pair of left and right support members 4 and 4 erected on the base 3, and a horizontal bar 5 that is bridged between the pair of support members 4 and 4 and is adjustable in height, a hanging member 6 that is a rod member hung from the horizontal bar 5 of the portal frame 2, and a hanging ring 7 that is fixed to the hanging member 6 and can surround the tension jack J1. The hanging ring 7 is swingably attached to the portal frame 2.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a tensioning jack hoisting device, a tensioning jack support base, and a tensioning method. [Background technology]

[0002] The tensioning jack itself is a device weighing several tens of kilograms, making it difficult to support it manually. Therefore, while the tension applied to the jack allows it to stand on its own during tensioning work, when setting or releasing the tensioning jack, the jack itself is usually suspended from above. However, when tensioning or releasing tendons such as prestressing steel strands using a tensioning jack under a deck slab with headroom restrictions, such as in the construction of a half-section deck, it is necessary to drive post-installed anchors (inserts) into the underside of the deck slab and attach metal fittings to the anchors to support the tensioning jack.

[0003] However, when installing, replacing, or releasing tensioning jacks, if the angle between the tensioning jack and the fixing device that secures the tensioning material or the tensioning frame changes, the tensioning jack must be reinserted. Simply fastening the tensioning jack to a metal fitting attached to the underside of the deck slab poses problems, such as insufficient stroke, insufficient working space, or a change in the angle between the tensioning jack and the tensioning frame, necessitating the need to detach the metal fitting and tensioning jack each time work is performed. Furthermore, driving construction anchors into the underside of the deck slab is undesirable, as it would result in defects in the final product, the deck slab. Therefore, a means of supporting the tensioning jack without changing the angle, height, or left-right position between the tension rod and the tensioning jack was desired, even in cases where overhead restrictions prevent the tensioning jack from being used by suspending it with a lifting device such as a chain block, or where there is insufficient working space.

[0004] For example, Patent Document 1 discloses a pretensioning device in which an anti-buckling member 27 is installed midway along the compression member 26 at a position where the inherent allowable buckling stress of the compression member 26 is not smaller than the generated buckling stress, and the compression member 26 is loosely fitted into an insertion space 33 formed in the anti-buckling member 27 so that it can slide (see claim 1 in the claims of Patent Document 1, paragraphs

[0024] to

[0032] of the specification, Figures 1 to 9 of the drawings, etc.).

[0005] However, the pretensioning device described in Patent Document 1 is a device for applying tension to PC steel strands used in the manufacture of prestressed concrete (PC) products in factories, and is not applicable to construction sites with headroom restrictions. Furthermore, in the past, tensioning jacks were often supported manually, and there was currently no particular prior art. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-182715 Summary of the Invention [Problem to be solved by the invention]

[0007] Therefore, the present invention was devised in consideration of the above-mentioned problems, and its purpose is to provide a tensioning jack hoisting device, tensioning jack support base, and tensioning method that can be applied even at construction sites with headroom restrictions, and that can maintain the angle and position once adjusted regardless of the operation of the jack. [Means for solving the problem]

[0008] The tensioning jack hoisting device of the first invention is a tensioning jack hoisting device that suspends and supports a tensioning jack that expands and contracts in response to tensioning operation, and is characterized in that it comprises a base that can be placed on a flat surface, a pair of left and right support members erected on the base, a portal frame consisting of a horizontal bar that is suspended between the pair of support members and whose height can be adjusted, a hanging member made of a rod member suspended from the horizontal bar of the portal frame, and a hanging ring that can surround the tensioning jack fixed to the hanging member, and the hanging ring is attached so as to be able to swing freely relative to the portal frame.

[0009] The tensioning jack hoisting device of the second invention is characterized in that, in the first invention, one or more long holes are formed in the horizontal bar, and the hoisting material is joined to the horizontal bar through the long holes.

[0010] The tensioning jack support base of the third invention is a tensioning jack support base that supports a tensioning jack that expands and contracts in response to tensioning operation, and is characterized in that it is equipped with a height-adjustable mounting base, and a tensioning jack hoisting device described in claim 1 or 2 is installed on the mounting base, and the tensioning jack is supported via the tensioning jack hoisting device.

[0011] The tension jack support base of the fourth invention is characterized in that, in the third invention, an inclined base with an inclined upper surface is placed on the mounting base, and the inclined base also supports the tension jack from below.

[0012] A tension jack support base according to a fifth aspect of the present invention is the tension jack support base of the third aspect of the present invention, characterized in that the mounting base is configured to be freely tiltable.

[0013] The tensioning method of the sixth invention is a tensioning method for tensioning tensioning material using a tensioning jack at a work site with headroom restrictions, and is characterized in that a tensioning jack that expands and contracts in response to the tensioning operation is supported using a tensioning jack support base described in any one of claims 3 to 5. [Effects of the Invention]

[0014] According to the first to sixth aspects of the invention, it can be applied to construction sites with overhead restrictions, and the tensioning jack's lifting height and lifting angle can be adjusted. Once the adjustment is made when the jack is set, a constant angle can be maintained from tension to release, allowing for safe and efficient work when replacing the jack or inserting and removing the tension rod. This significantly improves the work efficiency of tensioning work and reduces labor costs. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a side view showing a situation in which tendons are tensioned under a bridge deck using a tensioning jack support base according to an embodiment of the present invention. [Figure 2] FIG. 2 is a front view of the deck cut along a vertical plane, showing how tensioning jack supports are used to tension tendons under the deck of a bridge. [Figure 3] FIG. 3 is a front view showing the tension jack hoisting device according to this embodiment as viewed from the fixing side. [Figure 4] FIG. 4 is a left side view showing the tension jack hoisting device. [Figure 5] FIG. 5 is a plan view showing the tension jack hoisting tool. [Figure 6] FIG. 6 is a side view showing a state when a tensioning jack is installed in the tensioning method according to the embodiment of the present invention. [Figure 7] FIG. 7 is a side view showing the state at which tensioning begins when there is no tensioning jack hoisting device. [Figure 8] FIG. 8 is a side view showing a state in which a tension jack is replaced when there is no tension jack hoisting tool. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, an embodiment of a tensioning jack hoisting device, a tensioning jack support base, and a tensioning method according to the present invention will be described in detail with reference to the drawings.

[0017] [Tension jack support stand] First, a tensioning jack support base 10 and a tensioning jack hoisting device 1 according to an embodiment of the present invention will be described with reference to Figures 1 to 5. Figure 1 is a side view showing a situation in which a tensioning jack support base 10 according to this embodiment is used to tension tendons under a bridge deck, and Figure 2 is a front view showing a situation in which a bridge deck is cut along a vertical plane and a tensioning jack support base 10 is used to tension tendons under a bridge deck.

[0018] As shown in Figure 1, the tensioning jack support base 10 of this embodiment has a mounting base 11 that supports a tensioning jack J1 such as a center hole jack, and a tensioning jack hoisting device 1 and an inclined base 13 are installed on this mounting base 11, and is a base that suspends and supports the tensioning jack J1, which expands and contracts in response to the tensioning operation using the tensioning jack hoisting device 1.

[0019] (Tension jack support base) The tensioning jack support base 10 is a typical commercially available workbench with a mounting base 11 attached to the upper end of support columns 12 made of two steel pipes that can slide up and down, and the height of the mounting base 11 can be adjusted freely by changing the screw fastening positions of the two steel pipes of the support columns 12. The angle of the mounting base 11 can also be adjusted freely within a certain range relative to the support columns 12, and can be fine-tuned according to the angle of the tensioning jack J1 as well as the inclined surface 13a on the upper surface of the inclined base 13.

[0020] (sloping table) As shown in Figure 1, the upper surface of the inclined base 13 is an inclined surface 13a that is set at an angle that corresponds to the angle at which the tensioning member T1 protrudes from the fixing end B1a of the PCa slab (precast slab) B1 downward relative to the underside of the PCa slab B1, i.e., the angle at which the tensioning member T1 is fixed with a fixing device (not shown). Therefore, by simply placing the tensioning jack J1 along the inclined surface 13a of the inclined base 13, it is easy to maintain the basic angle between the tensioning frame TF and the tensioning jack J1 when fixing, even though the tensioning jack J1 expands and contracts in response to the tensioning operation.

[0021] 1 and 2, the height of this inclined base 13 is adjusted using a height adjustment block 14, and then the inclined base 13 is fixed to the mounting base 11 of the tensioning jack support base 10. Also, as shown in Fig. 2, the width of this inclined base 13 is set narrower than the distance between the support members 4 (described later) so that it can be installed between the tensioning jack hoisting devices 1.

[0022] <Tension jack lifting device> Next, the tensioning jack hoisting device 1 according to an embodiment of the present invention, which is also a component of the tensioning jack support base 10, will be described in more detail using Figures 3 to 5. Figure 3 is a front view of the tensioning jack hoisting device 1 according to this embodiment, as seen from the fixed side. Also, Figure 4 is a left side view of the tensioning jack hoisting device 1, and Figure 5 is a plan view of the tensioning jack hoisting device 1.

[0023] As shown in Figures 3 to 5, the tensioning jack hoisting device 1 includes a base 3 consisting of a rectangular frame that can be placed on the flat upper surface of the mounting platform 11, a pair of left and right support columns 4, 4 erected on the base 3, and a portal frame 2 consisting of a horizontal bar 5 that is suspended between the pair of support columns 4, 4 and whose height is adjustable. The tensioning jack hoisting device 1 also includes a hanging member 6 made of a rod suspended from the horizontal bar 5 of the portal frame 2, and a hanging ring 7 that can surround the tensioning jack J1 fixed to the hanging member 6, and has the function of suspending and supporting the tensioning jack J1 and maintaining the angle and position (height) once set, even when the tensioning jack J1 is replaced.

[0024] (base) The base 3 is a rectangular frame formed by welding, at their longitudinal ends, a pair of L-shaped angles 32, 32 each measuring 5 mm thick, 300 mm long, and L=40 mm x 40 mm, to the upper surfaces of a pair of flat bars 31, 31 each measuring 1.6 mm thick, 30 mm wide, and 340 mm long. The L-shaped angles 32, 32 connect the longitudinal ends of the flat bars 31, 31. The base 3 has a wide bottom surface area and functions as the base of the tensioning jack hoisting device 1, supporting it to prevent it from falling over when the tensioning jack hoisting device 1 is installed on the mounting platform 11.

[0025] (post material) The support members 4 are made of M20 fully threaded bolts, and a horizontal bar 5 is clamped and joined to the top of each of the pair of support members 4, 4 with a pair of upper and lower M20 nuts 4a, 4b, thereby spanning the tops of the support members 4, 4. The lower parts of the pair of support members 4, 4 are joined by welding to the outside of the longitudinally central flanges of the flat bars 31, 31 of the base 3, and the aforementioned base 3 and the later-described horizontal bar 5 form the portal frame 2. In this way, because the support members 4 are made of fully threaded bolts, the height of the flat bar 31 can be adjusted over a wide range, and even if the tensioning jack J1 moves out of position, it can be quickly and easily addressed.

[0026] (horizontal bar) The horizontal bar 5 is composed of a pair of L-shaped angles measuring 5 mm thick and 420 mm long, with a length of 50 mm by 50 mm. A pair of bolt holes (not shown) are drilled at both longitudinal ends of the horizontal bar 5 for inserting the M20 fully threaded bolts of the aforementioned support member 4. As shown in FIG. 5 , three elongated holes 51, 52, and 53 are drilled at the center at a predetermined interval (e.g., 75 mm) to insert the M10 fully threaded bolts of the suspension member 6 (described below). These elongated holes 51, 52, and 53 are elongated along the length (left to right when viewed from the front) so that the position of the suspension ring 7, which wraps around and supports the outer periphery of the tensioning jack J1, can be adjusted. Of course, since there is only one suspension member 6, there may also be only one elongated hole 51, 52, and 53.

[0027] (hanging material) 3, the hanging member 6 is a so-called battledore bolt, in which a trapezoidal metal plate 61 is welded to the tip (lower part) of an M10 fully threaded bolt 60. A bolt hole for bolting the hanging ring 7 is drilled in the center of the metal plate 61.

[0028] (hanging ring) The suspension ring 7 is made up of a pair of left and right semicircular plates 71, 72 formed by bending a 1.6 mm thick, 40 mm wide steel strip into a semicircular shape with an inner diameter of 120 mm (the inner diameter of the rubber material 73). As shown in Figure 3, rubber material 73 is attached to the inner surfaces of these pair of left and right semicircular plates 71, 72 to increase frictional resistance and prevent the tensioning jack J1 from slipping.

[0029] Furthermore, the flat upper flanges 71a, 72a of these semicircular plates 71, 72 of the hanging ring 7 are bolted together with M10 bolt sets 74 to the bolt holes of the battledore bolts of the hanging material 6, allowing the hanging ring 7 to swing freely within a certain angle range relative to the hanging material 6. Furthermore, by bolting together the flat lower flanges 71b, 72b with M10 bolt sets 74, the hanging ring 7 is able to clamp and hold the tensioning jack J1 (not shown) between the semicircular arc portions 71c, 72c.

[0030] [Tension method] Next, a tensioning method according to an embodiment of the present invention will be described in comparison with other tensioning methods using Figures 6 to 8. It is assumed that a tensioning jack support 10 (tensioning jack hoisting tool 1) is used to tension tendons T1 such as PC steel strands with tension jack J1 under a PCa deck B1 with a headroom restriction, such as in the construction of a half-section of a deck, at a construction site with a headroom restriction as described above.

[0031] (Installation of tension jacks) In the tensioning method according to this embodiment, first, as shown in Figure 6, a tensioning jack installation step is performed in which a tensioning jack J1 is installed by fitting a tensioning frame TF into the fixed end of the tendon T1. The tensioning jack support base 10 is installed on temporary scaffolding installed below the PCa deck B1. Figure 6 is a side view showing the situation when the tensioning jack is installed in the tensioning method according to this embodiment.

[0032] Specifically, in this process, the angle and height of the tensioning jack J1 are adjusted using the tensioning jack support base 10 (tensioning jack hoisting tool 1), and then the tension rod TR is inserted from the rear of the tensioning jack J1, the axis of the tension rod TR is aligned with the axis of the tensioning jack J1 and the fixed end of the tension member T1, and the tension rod TR is screwed into the tension member T1 to connect them.The tensioning jack J1 is then surrounded by the aforementioned hanging ring 7, bolted together, and suspended and supported by the tensioning jack hoisting tool 1, thereby positioning and fixing the angle and height and installing the tensioning jack J1.

[0033] As mentioned above, as a preliminary preparation, an inclined platform 13 having an inclined surface 13a corresponding to the gradient angle of the fixed end of the tension member T1 relative to the PCa deck slab B1 is prepared, and is installed on the mounting base 11 of the tensioning jack support base 10 using a height adjustment block 14, so that not only is the tensioning jack J1 suspended and supported by the tensioning jack hoisting device 1, but the inclined platform 13 is also installed to support the tensioning jack J1 from below.

[0034] (Starts nervous) In the tensioning method according to this embodiment, the tensioning jack J1 is then driven to start tensioning the tendon T1 connected to the tension rod TR.

[0035] At this time, tensioning force is input to the tensioning jack J1 due to the stroke of the tensioning jack J1, so the tensioning jack J1 can stand on its own without being supported. For this reason, if the tensioning jack hoisting device 1 is not present, the tensioning jack support base 10 must be lowered so as not to hinder the extension of the tensioning jack J1, as shown in Figure 7. Figure 7 is a side view showing the start of tensioning when the tensioning jack hoisting device 1 is not present.

[0036] However, in the tensioning method according to this embodiment, as shown in Figure 6, the tensioning jack J1 is basically supported by being suspended from the tensioning jack hoisting tool 1, so there is no need to lower the tensioning jack support base 10. However, in the tensioning method according to this embodiment, the tensioning jack support base 10 is temporarily lowered so that it is not supported from below, but because it is supported by being suspended from the tensioning jack hoisting tool 1, the angle and height of the tensioning jack J1 determined when the tensioning jack was installed as described above are maintained, eliminating the need to raise and lower the tensioning jack support base 10 each time.

[0037] Furthermore, when the stroke of the tensioning jack J1 reaches its maximum, the tensioning jack J1 must be replaced. To replace the tensioning jack J1, the tension rod TR must be temporarily fixed and the tension must be released. At this time, if the tensioning jack J1 is only supported from below, as shown in Figure 8, the tensioning jack support base 10, which has been lowered so as not to hinder the extension of the tensioning jack J1, must be raised again to support it. Figure 8 is a side view showing the tensioning jack replacement situation when the tensioning jack hoisting device 1 is not present.

[0038] Furthermore, if the tensioning jack support base 10 is lowered to replace the tensioning jack J1, the weight of the tensioning jack J1 will cause the tensioning jack J1 to become misaligned, and the time-consuming and laborious work that was done when installing the tensioning jack will need to be repeated to align the axis of the tension rod TR with the axis of the tensioning jack J1 and the fixed end of the tension material T1, and to adjust the angle and height of the tensioning jack J1.

[0039] However, in the tensioning method according to this embodiment, even when replacing the tensioning jack J1, the stroke can be replaced while the tensioning jack J1 is suspended and supported by the tensioning jack hoisting tool 1, so there is no need to align the axes or adjust the angle and height of the tensioning jack J1 again. This significantly improves the efficiency of the replacement work of the tensioning jack J1.

[0040] According to the tensioning jack support base 10 (tensioning jack hoisting device 1) and tensioning method of this embodiment described above, not only is the tensioning jack J1 supported from below by the inclined base 13, but the tensioning jack J1 is also suspended and supported by the tensioning jack hoisting device 1, so that by adjusting the tensioning jack when it is installed, a constant angle can be maintained from tensioning to release. This allows safe and efficient work even at construction sites with overhead restrictions when replacing tensioning jacks or inserting and removing tension rods, significantly improving the work efficiency of setting up tensioning jacks and replacing / releasing them, and reducing labor costs.

[0041] Furthermore, according to the tensioning jack support base 10 (tensioning jack hoisting device 1) and tensioning method of this embodiment, the suspension ring 7 of the tensioning jack hoisting device 1 is freely swingable within a certain angle range relative to the hoisting material 6, so that even if the tensioning jack J1 swings, it can follow to some extent. In this respect, too, it is possible to prevent the tensioning frame TF from coming off the tensioning jack J1, thereby improving the work efficiency of the tensioning work.

[0042] In addition, according to the tensioning jack support base 10 (tensioning jack hoisting device 1) and tensioning method of this embodiment, the tensioning jack support base 10 itself has a mounting base 11 that can be freely adjusted in height and angle (freely tilted). Therefore, even if the centers of the tension rod TR and the tensioning jack J1 become misaligned when installing or replacing the tensioning jack J1, the tensioning jack J1 can be reinstalled in a short time.

[0043] Furthermore, according to the tensioning jack support base 10 (tensioning jack hoisting device 1) and tensioning method of this embodiment, three long holes 51, 52, 53 are drilled in the horizontal bar 5 at a predetermined interval (for example, 75 mm) so that the position of the suspension ring 7 can be adjusted. This makes it easy to fine-tune the left and right position when installing the tensioning jack, and to quickly re-install the tensioning jack J1 if it becomes misaligned to the left or right. This also improves the work efficiency of installing, replacing, and releasing tensioning jacks.

[0044] The tensioning jack support base 10 (tensioning jack hoisting device 1) and tensioning method according to the embodiment of the present invention have been described in detail above, but the above-described and illustrated embodiments are merely specific examples of the present invention. Therefore, the technical scope of the present invention should not be interpreted as being limited by these embodiments.

[0045] In particular, the dimensions of each component described in the tensioning jack support base 10 (tensioning jack hoisting device 1) are merely examples of an embodiment of the present invention, and it goes without saying that these dimensions are not limited to these. [Explanation of symbols]

[0046] 1: Tension jack lifting device (tension jack support base) 2: Gate frame 3: Bass 31: Flat bar 32: L-shaped angle 4: Support material 4a, 4b: Nut 5: Horizontal bar 51, 52, 53: Long holes (bolt holes) 6: Hanging material 60: Fully threaded bolt 61: Metal plate 7: Hanging ring 71,72: Semicircular plate 71a, 72a: Upper flange 71b, 72b: Lower flange 71c, 72c: Arc section 73: Rubber material 74: Bolt set 10: Tension jack support base 11: Mounting table 12: Strut 13: Slope 13a: Inclined surface 14: Height adjustment block B1: PCa floor slab B1a: Fixed end T1: Tensile material J1: Tension jack TF: Tension stand TR: Tension rod

Claims

1. A tensioning jack hoisting device that suspends and supports a tensioning jack that expands and contracts in response to tensioning operation, The device comprises a base that can be placed on a flat surface, a pair of left and right support members erected on the base, a portal frame consisting of a horizontal bar that is suspended between the pair of support members and whose height can be adjusted, a hanging member consisting of a rod member suspended from the horizontal bar of the portal frame, and a hanging ring that can surround the tension jack fixed to the hanging member, The suspension ring is attached to the portal frame so as to be able to swing freely. A tension jack lifting device characterized by:

2. The horizontal bar has one or more long holes formed therein, and the hanging member is joined to the horizontal bar through the long holes.

2. The tension jack hoisting device according to claim 1,

3. A tensioning jack support base that supports a tensioning jack that expands and contracts in response to a tensioning operation, A height-adjustable mounting base is provided, and the tensioning jack hoisting device according to claim 1 is installed on the mounting base, and the tensioning jack is supported via the tensioning jack hoisting device. A tension jack support base characterized by:

4. An inclined platform with an inclined upper surface is placed on the mounting base, and the inclined platform also supports the tension jack from below. The tension jack support base according to claim 3,

5. The mounting table is configured to be tiltable. The tension jack support base according to claim 3,

6. A tensioning method for tensioning a tensioning member with a tensioning jack at a site with headroom restrictions, The tensioning jack support base according to any one of claims 3 to 5 is used to support a tensioning jack that expands and contracts in response to tensioning operation. A tension method characterized by:

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