JP3243161B2 - Suspension mechanism and suspension method for reinforced cage - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for suspending a reinforced concrete basket which is required when constructing a reinforced concrete underground wall or the like in the ground by an open-cutting method.

[0002]

2. Description of the Related Art A method of constructing a reinforced concrete underground wall in the ground by an open-cutting method is to excavate a ground to a predetermined depth from the surface using a clamshell or the like, and place a crane at a predetermined position in an excavated pit. After suspending the reinforced cage using a wire rope, put ready-mixed concrete into the pit.

[0003] Excavation is performed while filling the pit with mud water mainly composed of bentonite or the like for retaining the excavated surface, and concrete is poured at a position close to the bottom of the pit using a telemy pipe, and gradually poured. By raising the position, the mud is driven out of the pit and poured.

[0004]

Therefore, it is impossible for a person to enter the mine to perform work, and even in the work of hanging the reinforced cage, the wire rope cannot be removed from the suspended reinforced cage. For this reason, the wire rope was detached from the crane after the concrete was cast, and the wire rope was backfilled while remaining in the ground.

However, in this method, not only the wire rope is wasted, but also when the backfilled portion is re-excavated by using a machine, the wire rope may be entangled with the excavator and damage the machine. .

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to reduce the number of members abandoned in the ground when suspending a steel cage in a pit.

[0007]

According to the first aspect of the present invention, there is provided a hanging mechanism for hanging a reinforcing bar cage from the ground in an underground space formed by excavation. A first rod having a reverse threaded portion, and a second rod having a forward threaded portion at both the upper and lower ends.
2 and a bracket fixed to a rebar basket having a reverse threaded portion.

According to a second aspect of the present invention, in the first aspect, there is provided means for holding an upper end of each of the rods on the ground.

According to a third aspect of the present invention, in the first aspect of the present invention, a screw portion of a reverse screw screwed to the bracket is provided on a lower surface, and a screw portion of a reverse screw screwed to a lower end of the first rod is provided. A lock piece is further provided on the upper surface, and the diameter of the screw portion on the lower surface is set smaller than the diameter of the screw portion on the upper surface.

According to a fourth aspect of the present invention, there is provided a method for suspending a reinforced cage from the ground in an underground space formed by digging, wherein a bracket having a reverse threaded portion is fixed to the reinforced cage. A threaded portion of a positive screw is provided at the lower end, and a lower end of a first rod having a threaded portion of a reverse screw at the lower end is screwed to the bracket, and the reinforcing rod is hung down while supporting the first rod. After screwing the lower end of the second rod, which has a threaded portion of a positive screw at the lower end, to the upper end of the first rod, suspending the reinforced cage further while supporting the second rod, the second rod is turned upside down. Remove the lower end of the first rod from the bracket by rotating the screw in the direction of loosening.

According to a fifth aspect of the present invention, there is provided a method for suspending a reinforced cage from the ground in an underground space formed by digging, wherein a bracket provided with a reverse threaded portion is fixed to the reinforced cage. The lower end of the first rod provided with a threaded portion of a larger diameter reverse screw at the lower end thereof is connected to the bracket via a lock piece having a threaded portion of a reverse screw having a different diameter on the upper surface and the lower surface, respectively. After suspending the reinforced cage while supporting the first rod, the lower end of the second rod, which is provided with a threaded portion of a positive screw at both the upper and lower ends, is screwed to the upper end of the first rod, and the second rod is Then, the reinforcing rod is further hung, and then the second rod is rotated in a direction to loosen the reverse screw to release one of the screw portions of the reverse screw.

The invention of claim 6 is the invention of claim 4 or 5
In the invention of the third aspect, the reinforcing rod is suspended to a deeper position by sequentially locking another second rod at the upper end of the second rod.

[0013]

According to the first aspect of the present invention, the first and second rods are screwed together with a positive screw, and the first rod and the bracket are screwed together with a reverse screw. When the second rod is rotated in the forward direction in a state where these are connected, the threaded portion of the reverse screw is disengaged, and the bracket and the lower end of the first rod are separated.

According to the second aspect of the present invention, the holding means holds the upper end of the rod on the ground, thereby facilitating the extension of the rod.

According to the third aspect of the present invention, when the threaded portion of the reverse screw does not come off in the forward rotation operation, a stronger rotating force is applied to cut the threaded portion. The small diameter threaded portion between the piece and the bracket is threaded before the large diameter threaded portion between the rod piece and the first rod, and the first rod is recovered without damage.

In the invention of claim 4, the forward rotational torque applied to the second rod is directed in a direction to loosen the screwing of the first rod and the bracket and in a direction to tighten the screwing of the second rod and the first rod. Works. Therefore, after connecting the first rod and the second rod and suspending the reinforced cage,
2 Rotate the rod in the direction to loosen the reverse screw to
1 Rod separates from bracket.

According to the fifth aspect of the present invention, when the screwed portion of the reverse screw does not come off in the forward rotation operation, a stronger rotating force is applied to cut the screwed portion. The small diameter threaded portion between the piece and the bracket is threaded before the large diameter threaded portion between the rod piece and the first rod, and the first rod is recovered without damage.

According to the sixth aspect of the present invention, the reinforcing rods can be suspended to an arbitrary depth by the second rods sequentially connected.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS.

As shown in FIG. 1, the reinforcing bar 1 has a pair of
1 rod 2 and a number of second
Is suspended at the bottom of a pit 4 excavated from the surface by a rod 3 of Tunnel 4 is filled with mud mainly composed of bentonite to protect the excavated surface.

The first rod 2 and the second rod 3 are
As shown in FIG. 3, a male pipe member 6 (6A) and a female screw member 7 were welded to both ends of a steel pipe. The female screw member 7 has a rectangular outer shape as shown in FIG. 2, and the screw portion is a positive screw. Also, the male thread member of the first rod 2
6A threaded section is reverse thread, 2nd rod 3 external thread member
The threaded portion of No. 6 is machined into a positive screw.

The reinforcing bar 1 is, as shown in FIGS.
It consists of a main bar 1A and a distribution bar 1B, on which two brackets 8 are fixed in advance by welding. Bracket 8 has a reinforcing plate as shown in Figures 6 and 7.
U-shaped section welded to reinforced cage 1 via 9
8A and a female screw member 8B welded to the center.
The threaded portion of the female screw member 8B is machined into a reverse screw having a diameter smaller than the threaded portion of the female screw member 7 of the rods 2 and 3.

The first rod 2 and the bracket 8 are connected via a lock piece 10. The lock piece 10 is a block-shaped member having a female screw at the upper end and a male screw at the lower end. Each of these screws is processed into a reverse screw, and the female screw is screwed into the male screw member 6A of the first rod, and the male screw is screwed into the female screw member 8B of the bracket 8.

A hanging bracket 11 is attached to the upper end of the connected second rod 3. As shown in FIG. 8, the hanging metal fitting 11 has a band-shaped member to which clamps 15 for holding the second rod 3 are attached to both ends. Clamp 15
Has an inner diameter slightly larger than the outer diameter of the second rod 3,
2 Female threaded member with rectangular outer shape at the upper end of rod 2 7
The second rod 3 is supported in a rotatable state via the.
The clamp 15 is configured to be detachable by operating a screw (not shown). Note that the hanging bracket 11 is
Prepare pairs and use them alternately.

On the upper surface of the suspension fitting 11, a lock 13 for locking a wire rope 14 of a crane (not shown) is provided. Further, in the state where no lifting force is applied via the wire rope 14, the beam 12 crossing the opening of the pit 4 is sandwiched under the suspension metal 11 as shown in FIG. 2 Supported on the opening with the rod 3 locked.

Next, the operation will be described.

The reinforced cage 1 is excavated to a predetermined cross section and a predetermined depth by drilling, and is suspended in a state where the pit 4 is filled with muddy water. Prior to the suspension work, the following work will be performed on the ground.

That is, the male screw of the lock piece 10 is screwed into the female screw member 8B of the two brackets 8, respectively.
The male screw members 6A at the lower ends of the two first rods 2 are screwed into the female screws of these lock pieces 10, and the first rod
Connect the upper end of 2 with the hanging bracket 11 via the clamp 15.

After this operation, the hook 13 of the hanging metal 11
The first rod 2 and the reinforced cage 1 are lifted by the crane and suspended in the pit 4 via the wire rope 14 attached to the pier. Pass the beam 12 to the opening of the pit 4 and wire rope when the hanging bracket 11 is supported by the beam 12.
Loosen 14.

In this state, the male screw member 6 of the second rod is screwed to the female screw member 7 at the upper end of the first rod. The tip of the male screw member 6 is brought into contact with the female screw member 7, and the second rod 3 is held while holding the female screw member 7 so as not to rotate.
By rotating in the forward direction, the male screw member 6 is screwed into the female screw member 7.

After connecting the second rods 3 to the two parallel first rods 2 in this way, another hanging metal fitting 11 is attached to the upper part of the second rod 3 and the wire rope 14 is replaced. Then, lift the newly installed hanging bracket 11 with a crane. This allows the first
Release the load acting on the suspension fitting 11 attached to the rod 2, open the clamp 15 and remove the suspension fitting 11 from the first rod 2.

Then, the hanging fitting 11 is lowered by operating the crane until the hanging fitting 11 connected to the second rod 3 is supported by the beam 12.

Thereafter, in the same manner, two suspension fittings 1
While alternately using 1 and adding a new second rod 3 to the upper end of the second rod 3,
And hang it down to the bottom. The reinforced cage 1 supported via the rod is less likely to sway compared to a case where the reinforced basket 1 is directly suspended by a wire rope, and fine position control is possible.

FIG. 1 shows a state in which the squirrel cage 1 has reached the bottom of the pit 4. The length of the uppermost second rod 3 can be changed in advance according to the design depth of the pit 4. If
When the reinforced cage 1 reaches the bottom of the pit 4, the second rod 3
Can be positioned at a height suitable for subsequent work.

The tension acting on the first rod 2 and the second rod 3 is released at the same time when the reinforcing rod 1 reaches the bottom of the pit 4. In this state, the tension of the wire rope 14 is released, and the female screw member 7 of the uppermost second rod 3 protruding above the ground is rotated in the forward direction.

This rotational torque acts in the direction of tightening the threaded portion of the positive screw between the rods, while the two reverse threaded portions between the first rod 2 and the bracket 8 loosen the connection. Act on. Therefore, by removing the threaded portion of the reverse screw by this operation and lifting the suspension fitting 11 with a crane, all the rods can be recovered at the same time.

At this time, it is possible to set in advance which of the two threaded portions of the reverse screw should be removed. When the lock piece 10 is to be left together with the reinforced cage 1 and only the rods 2 and 3 are to be recovered, the female screw member 8B of the bracket 8
The female screw of the lock piece 10 and the first female screw
The female thread of the lock piece 10 and the first rod 2 are used to increase the play of the threaded portion of the rod 2 with the male screw member 6A.
The length of the threaded part with the male screw member 6A of the bracket 8
The length of the threaded portion between the female screw member 8B of the lock piece 10 and the male screw of the lock piece 10 may be reduced.

Incidentally, even if the lock piece 10 comes off and is recovered together with the rods 2 and 3, no problem occurs.

On the other hand, it is also conceivable that none of the reverse threaded portions comes off for some reason, for example, a foreign matter is stuck in the threaded portion. In such a case, it is necessary to apply a large torque to the second rod 3 at the upper end to thread the reverse thread. In this case, the male thread member 6A of the first rod 2
The external thread of the smaller diameter lock piece 10 is always threaded. Therefore, the male screw member 6A of the first rod 2
Is not damaged and the first rod 2 can be used again after recovery.

Thus, the recovered first rod 2
And the second rod 3 can be diverted many times to another span. Since only the bracket 8 and the lock piece 10 fixed to the reinforced cage 1 are left in the pit 4,
Even if the backfill part after concrete casting is re-excavated, no trouble occurs.

[0041]

According to the first aspect of the present invention, the first rod is connected to the lower part of the second rod via a forward screw, and the lower end of the first rod is connected to the bracket fixed to the reinforcing bar through the reverse screw. Since the two rods are connected, the screwed part of the reverse screw is released by the rotation of the second rod in the forward direction, and the first rod and the second rod should be easily collected after the reinforced cage is suspended from the ground to the underground space. it can. For this reason, it is possible to minimize the number of members left in the ground after hanging the reinforced cage, and to prevent the remaining members from causing trouble during re-excavation, etc.
Construction costs can be reduced.

According to the second aspect of the present invention, since the rod holding means for holding the upper end of the rod on the ground is provided, the extension of the rod is facilitated.

According to the third and fifth aspects of the present invention, since the lock piece having the threaded portion having a different diameter is interposed between the first rod and the bracket, the threaded portion of the reverse screw does not come off for some reason, When the screw is forcibly cut, the reverse screw threaded portion between the lock piece and the bracket is threaded to prevent damage to the reverse screw of the first rod. Therefore, the durability of the first rod is improved.

According to a fourth aspect of the present invention, a reinforcing rod is hung via a first rod connected to a bracket of the reinforcing rod via a reverse screw, and a lower end of the second rod is fixed to an upper end of the first rod. Connect via screws and suspend the squirrel cage deeper. By rotating the second rod in the direction that the reverse screw loosens, the reverse screw of the first rod comes off. For this reason, the first rod underground can be
2 It is possible to collect together with the rod, reducing the number of members remaining in the ground after hanging the reinforced cage, preventing the remaining members from causing trouble during re-excavation, etc., and reducing the construction cost. Can be reduced.

According to the invention of claim 6, since another second rod is sequentially locked on the upper end of the second rod, it is possible to suspend the reinforcing bar to an arbitrary depth.

[Brief description of the drawings]

FIG. 1 is a side view of a suspension mechanism according to an embodiment of the present invention.

FIG. 2 is a front view of the female screw member.

FIG. 3 is a side view of the first rod.

FIG. 4 is a side view of the bracket.

FIG. 5 is a diagram showing an arrow AA in FIG. 4;

FIG. 6 is an enlarged side view of the bracket showing the embodiment of the present invention.

FIG. 7 is a view taken along the line BB in FIG. 6;

FIG. 8 is a side view of the hanging fitting showing the embodiment of the present invention.

[Explanation of symbols]

 1 Reinforcing cage 2 First rod 3 Second rod 4 Downhole 6 Male thread (positive thread) 6A Male thread (reverse thread) 7 Female thread 8 Bracket 10 Lock piece

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Shuichi Yahagi 3-19-6 Higashi-Ueno, Taito-ku, Tokyo Inside the Teito Metropolitan Expressway Corporation (56) References JP-A-5-214813 (JP, A) 1986-113786 (JP, U) JP-A 53-78814 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B66C 1 / 62,1 / 66 E04C 5/06

Claims (6)

(57) [Claims] 1. A hanging mechanism of a reinforcing cage for hanging a reinforcing cage from the ground in an underground space formed by digging, wherein a first threaded portion is provided at an upper end, and a reverse threaded portion is provided at a lower end. Characterized by comprising a second rod having a front threaded portion at each of its upper and lower ends, and a bracket fixed to a reinforcing bar having a reverse threaded portion. Hanging mechanism. 2. The hanging mechanism of a reinforced cage according to claim 1, further comprising means for holding an upper end of each of the rods on the ground. 3. A lock piece further comprising a screw portion of a reverse screw screwed to the bracket provided on a lower surface, and a screw portion of a reverse screw screwed to a lower end of the first rod provided on an upper surface. The suspension mechanism for a reinforced cage according to claim 1, wherein a diameter of the screw portion on the lower surface is set smaller than a diameter of the screw portion on the upper surface. 4. A method of suspending a reinforced cage from the ground in a subterranean space formed by digging, wherein a bracket provided with a reverse threaded portion is fixed to the reinforced cage, and a screw having a positive screw is provided at an upper end. The lower end of the first rod having a mating portion and having a threaded portion of a reverse thread at the lower end is screwed into the bracket, and
1 After suspending the reinforced cage while supporting the rod, screw the lower end of the second rod, which has a threaded part of a positive screw at both the upper and lower ends, to the upper end of the first rod, and support the second rod. And further removing the lower end of the first rod from the bracket by rotating the second rod in a direction to loosen the reverse screw after suspending the reinforcing cage further. 5. A method for suspending a reinforced basket from above the ground in an underground space formed by excavation, wherein a bracket provided with a threaded portion of a reverse screw is fixed to the reinforced basket, 1st thread provided with screw thread at the lower end
The lower end of the rod is connected to the bracket via a lock piece having a threaded portion of a reverse screw having a different diameter on the upper surface and the lower surface, and the reinforcing rod is hung down while supporting the first rod. The lower end of the second rod, which is provided with a threaded part of a positive screw at both the lower end and the lower end of the second rod, is screwed to the upper end of the first rod, and the reinforcing rod is further suspended while supporting the second rod. A method of suspending a reinforced basket, wherein one of the screw portions of the reverse screw is released by rotating the reverse screw in a loosening direction. 6. The method for suspending a reinforced cage according to claim 4, wherein the reinforced cage is suspended to a deeper position by sequentially locking another second rod to an upper end of the second rod.