JP2008050868A - Wooden concrete form - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To facilitate recycling of a used wooden concrete form with a damaged surface, and to reduce a form storage space in a construction field by virtue of the recycling. <P>SOLUTION: The wooden concrete form 13 is reinforced by attaching a wooden stiffener 12 to a rear surface of plywood 11 having a thickness (s) of 9 to 15 mm. Then a cardboard plate 16 obtained by intimately laminating polyolefin films or polyester films 14, 15 each having a thickness of 30 to 100 μm to obverse and reverse surfaces of a cardboard 10, and having a total thickness (t) of 2.2 to 4.2 mm and a bulk specific gravity of 0.7 to 0.8 g/cm<SP>3</SP>, is superposed on the front surface of the plywood 11, and U-shaped tackers 20 are driven from the front surface of the cardboard plate 16 to the sash bar 12 at intervals (L) of 150 to 250 mm along the sash bar 12. In each tacker 20, a length (h) of a tacker leg 17 is longer than the total thickness of the plywood 11 and the cardboard plate 16, and a maximum dimension (f) of a tacker leg 17 cross section is not larger than 1.5 mm. Thus the cardboard plate 16 is rigidly nailed to the plywood 11 by the U-shaped tackers 20. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a wooden concrete formwork (hereinafter referred to as a wooden formwork) in which a crosspiece is attached to the back surface of a plywood.

In building work, the wooden formwork used for concrete placement below the floor is removed and reused in sequence to the concrete placement on the floor. The concrete residue is fixed to the surface of the plywood of the wooden formwork that has been repeatedly used in this way, and when it is used repeatedly, the unevenness due to the concrete residue is transferred to the surface of the concrete casting surface. The finish is poor. The number of times of concrete placement that can be used repeatedly is generally 5 to 7 times, and the wooden formwork that has been used beyond its service life is disposed of.
For this reason, in high-rise building construction, a large amount of wooden formwork, which is expected to be discarded, will be carried to the construction site, and it will be difficult to secure the storage space.

  In order to increase the service life of the wooden formwork and to make it easy to peel from the concrete casting surface, it has been attempted to adhesively laminate a polyolefin film on which the cement is difficult to adhere to the surface of the plywood (for example, Patent Documents). 1 and 2). The adhesion lamination of the polyolefin film to the plywood is performed by heating and melting the polyolefin resin, extruding it from the T-die laminator to the surface of the plywood, and fusing it with a press roll. In that case, the plywood is preheated to the melting temperature of the polyolefin resin so that the heated and melted polyolefin film is fused without cooling.

  As a method for adhesively laminating a polyolefin film on the surface of a plywood, a method is also known in which a polyolefin film is once adhesively laminated on a reinforcing paper and then adhered to the surface of the plywood via the reinforcing paper (see, for example, Patent Document 3). ).

JP 59-145865 A Japanese Patent Application Laid-Open No. 08-021084 JP 02-144471 A

  Polyolefin film laminated on wooden formwork is rubbed against slightly adhered concrete residue or corners of wooden formwork in the process of repeatedly using wooden formwork for transportation, stacking, storage, assembly, etc. Scratch marks are likely to be generated, and the concrete residue adhered thereto generates further fine holes and scratch marks, and eventually the function of the polyolefin film is lost and must be discarded.

Of course, it is conceivable to replace the damaged polyolefin film, but the damaged polyolefin film is easily broken and cannot be peeled cleanly from the plywood.
Even if it can be peeled cleanly, in order to adhere and laminate the polyolefin film to the plywood, a large device such as a T-die, laminator, press roll, preheating device is required. The film cannot be replaced, and you must rely on a specialized manufacturer. However, the recycled wooden formwork is expensive due to the collection, cleaning, transportation and storage of the used wooden formwork. And even if the used wooden formwork is discarded, it is costly and may cause pollution problems.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to make it possible to recycle a used wooden formwork even at a construction site, so that it is not difficult to secure a storage space for the wooden formwork at the construction site.

  The wooden formwork according to the present invention comprises (a) a plywood 11 attached and reinforced on the back surface of a plywood 11 having a thickness (s) of 9 to 15 mm, and (b) a polyester having a thickness of 30 to 100 μm on the front and back of the cardboard 10. A paper board 16 having a total thickness (t) of 2.2 to 4.2 mm formed by closely laminating films, preferably polyolefin films 14 and 15, is superimposed on the surface of the plywood 11; The U-shaped tacker nail 20 whose length (h) is longer than the total thickness (s + t) of the plywood 11 and the paper board 16 and whose maximum dimension (thickness f) in the cross section of the nail leg 17 is 1.5 mm or less is the surface of the paper board 16 The first feature is that the paper board 16 is fixed to the plywood 11 by a U-shaped tacker nail 20.

  The second feature of the wooden formwork according to the present invention is that, in addition to the first feature, a water repellent solution 24 is applied to the end face 23 of the cardboard 10 exposed at the periphery of the paper board 16. It is in.

  A third feature of the wooden formwork according to the present invention is that, in addition to any of the first and second features, the cardboard 10 is formed by laminating a plurality of base papers 27 with a water-soluble resin 28 interposed therebetween. The thickness of the cardboard 10 is 2 to 4 mm.

  The fourth feature of the wooden formwork according to the present invention is that, in addition to any of the first, second, and third features, the nail head 18 of the U-shaped tacker nail 20 is connected to the ridge line 21 of the plywood 11. In the direction (θ) inclined by 30 to 60 degrees.

  The fifth feature of the wooden formwork according to the present invention is the length (h) of the nail leg 17 of the U-shaped tacker nail 20 in addition to any of the first, second, third, and fourth features. Is longer than the total thickness (s + t) of the plywood 11 and the paper board 16, and the U-shaped tacker nail 20 is driven along the pier 12 from the surface of the paper board 16 toward the pier 12.

In the present invention, the front and back of the paper board 16 are waterproofed with the films 14 and 15, and water hardly permeates the cardboard 10 sandwiched between the front and back films 14 and 15.
Further, since the nail leg 17 of the U-shaped tacker nail 20 for nailing and fixing the paper board 16 to the plywood 11 is thin, it is difficult for water to penetrate from the nail head 18 to the cardboard 10 along the nail leg 17 that has been driven.
For this reason, in the hydration reaction process in which the cast concrete hardens, the cardboard 10 does not swell and deform due to absorption of moisture of the cast concrete, and the paper board 16 maintains rigidity equal to or higher than the plywood 11. The concrete placement surface is finished smoothly along the surface of the smooth paper board.

In particular, the length (h) of the nail leg 17 of the U-shaped tacker nail 20 is longer than the total thickness (s + t) of the plywood 11 and the paper board 16, and the U-shaped tacker nail 20 is moved along the pier 12 from the surface of the paper board 16. When driving toward the pier 12, the driven nail tip 19 bites into the pier 12, so that water does not ooze from the nail tip 19 into the cardboard 10.
Since the nail tip 19 is covered with the pierced pier 12, the nail tip 19 is not rusted and the tacker nail 20 is not easily removed from the plywood, and the U-shaped tacker nail for fixing the paper board to the plywood is fixed. Since the 20 nail legs 17 have a maximum cross-sectional dimension (thickness f) as small as 1.5 mm or less, the resistance received from the plywood 11 is small, and the tacker nail 20 can be easily pulled out.
Therefore, when the surface film 14 is damaged and the concrete residue adheres and the wooden formwork has to be discarded, if the paper board 16 is warped, the nail leg 17 is pulled out from the plywood 11, and the cardboard Since the front and back surfaces of the paper 10 are reinforced by the films 14 and 15, a problem that a hole is generated in the paper board 16 by the nail head 18 is avoided.
At this time, even if a hole is formed in the paper board 16 by the nail head 18 and the tacker nail 20 is left behind in the plywood 11, a brazing material such as a screwdriver is provided in the gap 22 between the nail leg 17 and the nail leg 17. Can be easily pulled out.
Since the nail tip 19 bites into the pier 12, the risk of injury by touching the nail tip 19 protruding from the back surface of the plywood 11 is also avoided.

In this manner, the tacker nail 20 is easily pulled out and the paper board 16 is easily peeled off from the plywood 11. Therefore, when the surface film 14 is damaged, the paper board 16 is removed from the plywood 11 and pasted on a new paper board at the concrete placing construction site. Alternatively, the wooden form 13 can be regenerated and used repeatedly until the plywood 11 and the pier 12 are corroded.
Therefore, the number of used wooden formwork that must be disposed of at the construction site is drastically reduced, and it is no longer necessary to carry a large amount of wooden formwork that is expected to be disposed of even in high-rise building construction. You don't have to worry about securing the storage space for the frame.

  By crushing the paper board 16 that has been removed by damaging the surface film 14 of the wooden formwork according to the present invention, it can be separately collected into pulp fibers that are the material of the cardboard 10 and fragments of the films 14 and 15. Becomes a recycled resource of the new paper board 16, and it is not necessary to discard the removed paper board, and pollution problems associated with disposal can be avoided.

In the present invention, since the thickness t of the paper board 16 is about 3 mm, it is difficult for water to penetrate from the end face 23 into the thick paper 10. In particular, when the water repellent solution 24 is applied to the end face 23, the water repellent layer 25 in which the pulp fibers adsorbing the water repellent 24 are integrated with the water repellent 24 is about 3 mm. Since the water repellent layer 25 is in close contact with the front and back films 14 and 15, the penetration of water from the end face 23 into the cardboard 10 is completely blocked, and the water repellent The layer 25 cannot peel from a very narrow gap between the front and back films 14 and 15.
Accordingly, the moisture of the cast concrete does not permeate from the end surface 23 and the cardboard 10 does not swell and deform, and the concrete cast surface is smoothly finished according to the paper board 16.

  In the thick paper 10 in which a plurality of base papers 27 are laminated via the water-soluble resin 28, when the paper board 16 is removed from the plywood 11, a hole in the nail head 18 hardly occurs due to the multilayer structure of the thick paper 10. Can be easily removed from the plywood 11 by pulling up the nail leg 17.

The direction of the length direction of the nail head 18 of the U-shaped tacker nail 20 for nailing and fixing the paper board 16 to the plywood 11 is aligned with a certain direction (θ) inclined by 30 to 60 degrees with respect to the ridge line 21 of the plywood 11. Then, at a corner 26 of the mold 13 orthogonal to the length direction of the nail head 18, a thin plate such as a knife or a driver is inserted between the paper plate 16 and the plywood 11, and the paper plate 16 is warped from the plywood 11, The two nail legs 17 and 17 of the cutter nail 20 adjacent to the cutter nail 20 at the corner portion 26 are also continuously pulled out in a vine manner.
At that time, since the pulling stress acts evenly on the entire surface of the nail head 18 from the paper board 16, occurrence of a hole in the paper board 16 by the nail head 18 is also avoided.
Thus, according to the present invention, the paper board 16 with the damaged surface film 14 can be easily removed from the plywood board 11, and the wooden formwork 13 can be easily regenerated by being pasted on a new paper board.

The bulk specific gravity of the paper board 16 is preferably finer than the bulk specific gravity of the plywood, generally 0.7 to 0.8 g / cm ³ . Incidentally, the bulk specific gravity of commercially available plywood is generally 0.5 g / cm ³ .
The driving interval (L) of the tacker nails 20 driven along the pier 12 is preferably 150 to 250 mm.
The water repellent solution 24 to be applied to the end face 23 of the paper board 16 includes commercially available water repellents such as silicone water repellents, fluorine water repellents and paraffin / wax water repellents, as well as kerosene and shaft oil. Oil agents such as heavy oil and edible oil can be used.
When the water repellent solution 24 is applied after nailing and fixing the paper board 16 to the plywood 11, even if the water repellent 24 adheres to the end surface of the plywood 11 or penetrates into the gap between the plywood 11 and the paper board 16. Good.
The water repellent 24 soaks into the end face 23 of the cardboard 10 sandwiched between the front and back films 14 and 15 to form a water repellent layer 25 integrated with the pulp fiber, and the end face 23 is placed on the concrete. Since the surface is not touched directly, the quality of the cast concrete is not impaired by the water repellent 24.

The front and back films 14 and 15 are made of a polyester resin, preferably a polyolefin resin, melted and extruded from a T-die laminator and fused and laminated on the front and back of the cardboard 10, and the pre-formed films 14 and 15 are used for the cardboard 10 It can also be fused by heating.
A primer resin 29 (undercoat adhesive film) can be laminated on the bonding surface of the cardboard 10 or the films 14 and 15.
The primer resin 29 may be an emulsion type or an organic solvent-dissolved solution type.
The primer resin 29 can be heat-melted and extruded from the T die / laminator to the cardboard 10 or the films 14/15 to be fused, and can be bonded and laminated by pressing with a press roll.

  The thickness (t) of the paper board 16 is preferably 3 mm. Then, when using a plywood 11 having a nominal thickness (s) of 9 mm, 12 mm, or 15 mm, preferably called a control panel, and preferably having a nominal thickness (s) of 9 mm, the total thickness of the plywood 11 and the paper board 16 is used. (S + t) is equal to the nominal thickness (12 mm) of the control panel, and because the paper board 16 is attached to the plywood of the conventional wooden formwork, the dimensions within the concrete placement space partitioned by the wooden formwork 13 of the present invention Since it is not necessary to calculate and set (inner method) according to the thickness (t) of the paper board 16, it is convenient in designing the concrete placement space.

As the tacker nail 20, commercially available products having a nominal dimension h of the nail leg 17 and a nominal dimension w of the nail head 18 of 13 mm × 4 mm, 13 mm × 9 mm, 19 mm × 4 mm, and 19 mm × 9 mm can be used.
The commercially available tacker nail is extremely thin with a depth dimension (f) of around 1.2 mm, a wall thickness dimension (e) of around 0.7 mm, and a cross-sectional area of 1 mm ² or less (around 0.8 mm ² ). Since water does not easily permeate into the cardboard 10 along the line 17, and when the damaged paper board 16 is removed from the plywood 11 and replaced with a new paper board, the tacker nail 20 can be easily pulled out, because it is a commercial product. It can be obtained at a low cost and is very convenient for carrying out the present invention.
The tacker nail 20 can be driven from the surface of the paper board 16 toward the pier 12 using an automatic nail driver (air tacker).

It is a perspective view of the wooden concrete formwork which concerns on this invention. It is a principal part expanded sectional view of the wooden concrete formwork which concerns on this invention.

Explanation of symbols

10: cardboard 11: plywood 12: plinth 13: form 14: film 15: film 16: paper board 17: nail leg 18: nail head 19: nail tip 20: tack nail 21: ridgeline 22: gap 23: end face 24: repellent Liquid solution 25: Water repellent layer 26: Corner 27: Base paper 28: Water-soluble resin 29: Primer resin

Claims (5)

(A) In a wooden concrete formwork (13) reinforced by attaching a crosspiece (12) to the back surface of a plywood (11) having a thickness (s) of 9 to 15 mm,
(B) A paper board (16) having a total thickness (t) of 2.2 to 4.2 mm formed by closely laminating a polyolefin or polyester film (14, 15) having a thickness of 30 to 100 μm on the front and back of the cardboard (10). , Superimposed on the surface of the plywood (11),
(C) The paper board (16) is nail-fixed to the plywood (11) by a U-shaped tacker nail (20) whose maximum dimension (f) in the cross section of the nail leg (17) is 1.5 mm or less. Wooden concrete formwork.   The wooden concrete formwork according to claim 1, wherein a water repellent solution (24) is applied to the end face (23) of the cardboard (10) exposed at the periphery of the paper board (16). .   A cardboard (10) comprising a plurality of base papers (27) laminated via a water-soluble resin (28), wherein the thickness of the cardboard (10) is 2 to 4 mm. A wooden concrete formwork according to any one of the above.   The nail head (18) of the U-shaped tacker nail (20) is directed in a direction (θ) inclined by 30 to 60 degrees with respect to the ridge line (21) of the plywood (11). Item 4. A wooden concrete formwork according to any one of Items 1, 2 and 3.   The length (h) of the nail leg (17) of the U-shaped tacker nail (20) is longer than the total thickness (s + t) of the plywood (11) and the paper board (16), and the U-shaped tacker nail (20) The wooden concrete formwork according to any one of claims 1, 2, 3 and 4, wherein said wooden concrete formwork is driven from the surface of the paper board (16) toward the pier (12) along the surface.

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