JP4799923B2 - Formwork support - Google Patents

Description

  The present invention relates to a formwork support used in a formwork when constructing a concrete structure.

  Construction of various concrete structures is carried out by, for example, screwing a formwork support having a generally truncated cone shape, which is also called Con (registered trademark) or cone, at both ends of the separator and having a screw shaft at the center. Form clamp の such as foam tie (registered trademark) on the male thread part of the mold support that protrudes from the outer surface of the mold support. After the molds are fixed upright at predetermined intervals by screwing, the concrete is placed between these molds. Then, when the mold is removed after the concrete is hardened, the mold support attached to the end of the separator is exposed in a state where it is buried in the surface of the concrete frame. These formwork supports are removed by using an appropriate removal tool, and then the substantially frustoconical trace hole remaining thereafter is filled with an appropriate method from the viewpoint of waterproofing and aesthetics.

The structure of such a mold support has an internal thread formed on one end side through a flange provided on the end surface thereof and reaching the inside of the substantially cylindrical body, and the other end of the body A metal shaft body in which a square portion and a male thread portion are sequentially formed, and a synthetic resin that is coaxial with the shaft body and has a large-diameter side positioned on the male thread portion side and is externally fitted to the body portion. What consists of a combination with a truncated-conical cylindrical frame is widely known (patent documents 1 and 2). These prior art formwork supports are press-fitted from the male thread side of the shaft body in the direction from the small diameter side to the large diameter side of the frame body, and are substantially circular in cross section provided in the small diameter side portion of the frame body Both members are integrated by fitting the gripping part consisting of the through-holes and the body of the shaft body formed on the outer peripheral surface of the substantially circular cross section in an interference fit state. It has become.
Japanese Utility Model Publication No. 6-37163 JP 2004-211148 A

  And the above-mentioned formwork support which is buried in the surface part of the concrete frame after mold removal is fitted with a box wrench etc. to the square part of the shaft body, and the female thread part of the shaft body is separated from the separator by its rotation. It is pulled out together with the frame while letting go. That is, in these formwork supports, it is basically assumed that the frame body is extracted while rotating together through the shaft body. Therefore, both members are used so that only the shaft body does not slip during the extraction operation. A strong unity between them is required. Therefore, the shaft body and the gripping portion of the frame are usually designed with a fairly tight dimensional tolerance within a range in which the gripping portion of the frame does not split when fitted together.

  By the way, although these formwork supports are made of synthetic resin with a low coefficient of friction such as polypropylene as a material of the frame, countless scratches occur on the outer peripheral surface of the frame due to its use, and its low friction property Will be diminished and concrete will adhere more easily. When the formwork support in such a state is used, the frame attached to the surrounding concrete is removed by cutting off the attachment between the two by rotating the shaft, so a large rotational force is required. It is said. This reduces the efficiency of the extraction work in the short term due to an increase in the size of the tool, etc., but in the long term, the gripping force at the fitting part of the synthetic resin frame body to the metal shaft body is greatly increased by repetition of this. It will be a factor to decrease. Thus, when the fitting state of the frame body and the shaft body becomes loose, the frame body easily falls off the shaft body. As a result, not only is it necessary to re-insert the separated parts at the time of use, but both members may be separated during the assembly work of the mold. Since these cause the workability to be greatly reduced, the actual situation is that the formwork support in such a state is discarded. Furthermore, if the frame body and shaft body are loosely fitted, it may not be said that the number of times that the frame body and shaft body can be diverted is sufficient, such as being separated at the storage location or in the field, and either member is lost. There was room for improvement.

  The present invention has been made in view of these problems of the prior art, and an object thereof is to provide a mold support having excellent durability.

Therefore, in the present invention, in order to solve the above-described problem, a female thread portion that penetrates the collar portion provided on the end surface on one end side and reaches the inside of the substantially cylindrical trunk portion is formed, and the other end side of the trunk portion is formed. A metal shaft body in which a square portion and a male screw portion are sequentially formed, and is coaxially connected to the shaft body and is externally fitted to the body portion with the large-diameter side being the male screw portion side and provided on the small-diameter side. A frame with a substantially truncated cone shape made of a synthetic resin that is engaged with the shaft body at the gripping portion, and after the mold clamping bar that engages with the male thread portion of the shaft body is removed, the frame portion is fitted into the square portion. In the formwork support that is detached from the surface of the concrete housing by removing the female screw portion screwed into the end portion of the separator by rotation of the combined removal tool, the shaft body is separated from the male screw portion side. insertion in a grip portion of the frame, the mutual axis by engaging the large diameter side end face of the grip portion of the frame The locking portion comprising a circular projection to resist separation into countercurrent with the barrel outer peripheral surface adopts the technical means that engaged to be idle from one another at a predetermined rotational force.

According to the formwork support according to the present invention, the following effects can be obtained.
(1) The shaft centered on the outer peripheral surface of the body portion of the shaft body to be fitted with the frame body by being inserted into the gripping portion of the frame body from the male threaded portion side and engaged with the large diameter side end surface of the gripping portion of the frame body Synthetic resin frame body for metal shaft body that is easy to manufacture because it is easy to fit the frame body to the shaft body because it is provided with a locking part consisting of an annular projection that resists separation in the direction. Even when the gripping force is reduced and the fitting state between the two becomes loose, the frame body is less likely to fall off the shaft body, leading to improved durability.
(2) Since the shaft and the frame are idled with a predetermined rotational force in the sampling operation, in the situation where the frame is attached to concrete, only the shaft remains with the frame attached to the concrete. Can be idle. Then, as the idling shaft body moves in the direction of separation from the separator, the frame body is pushed by the collar portion at the rear end portion of the shaft body. As a result, the adhesion between the frame body and the concrete is cut off, and the frame body and the shaft body can be reliably and easily removed from the surface of the casing.

In the mold support according to the present invention, as a locking portion for preventing separation of the frame body and the shaft body, the frame body is gripped by press-fitting into the outer peripheral surface of the metal shaft body from the male screw side. If an annular protrusion that can be inserted into the part is formed, and this protrudes and engages near the large-diameter side end face of the grip part of the synthetic resin frame, its locking force can be effectively applied, It is also advantageous from the viewpoint of manufacturing such as durability as a mold support and assembly work of the frame body and the shaft body . Note that the inner peripheral surface of the gripping portion in the synthetic resin frame does not have to be a continuous circumferential surface, and grooves parallel to the axial direction are formed at equal intervals in the circumferential direction as shown in the following examples. Or a polygonal shape such as a dodecagon. Furthermore, the same applies to the outer peripheral surface of the body portion of the shaft body, and it is sufficient that at least one of the members has a circular surface, and various modifications can be made within the technical concept of the present invention.

  1 and 2 are a partial cross-sectional view and a side view, respectively, of a formwork support according to a first embodiment of the present invention. The illustrated mold support 1 includes a metal shaft 2 and a synthetic resin frame 3. The shaft body 2 is provided with a flange 4 on an end surface on one end side, and a length from which the female thread portion 5 passes through the center to the inside of the trunk portion 6 from the flange 4 toward the other end. Is formed. An annular projection 7 is formed on the outer peripheral surface of the cylindrical body 6 at a position spaced from the flange 4 as a locking portion for the frame 3 described later. On the end side, a hexagonal nut-shaped square portion 8 and a male screw portion 9 are sequentially formed toward the end portion. In addition, when inserting the shaft body 2 into the frame body 3, the annular protrusion 7 is inclined so that the male threaded portion 9 side is inclined so that the annular protrusion 7 is not caught in the gripping portion and the locking force is effectively exhibited. Has been processed.

  On the other hand, the frame 3 is made of a synthetic resin such as polypropylene, and is formed in a substantially truncated cone shape as a whole. On the small diameter side, a concave portion 10 that fits with the flange portion 4 of the shaft body 2 is formed on the end face, and is adjacent to the concave portion 10 and fits with the trunk portion 6 of the inserted shaft body 2. As is clear from FIG. 2, the portion 11 is formed on the inner surface in which a plurality of arc-shaped grooves 12 are formed at equal intervals in the circumferential direction and parallel to the shaft center, and serves as a grip portion for the shaft body 2. Note that the inner diameter of the grip portion 11 excluding the arc-shaped groove 12 is set to be slightly smaller than the outer diameter of the body portion 6 of the shaft body 2 so as to be in an interference fit state when both are integrated. The Further, a gap 13 is formed between the outer peripheral side of the gripping part 11 and the outer peripheral wall, and a plurality of ribs 14 continuous from the inside of the gap 13 toward the end surface on the large diameter side are equally spaced on the inner surface in the circumferential direction. Is provided.

  The shaft body 2 and the frame body 3 are assembled by inserting the shaft body 2 into the grip portion 11 of the frame body 3 from the male screw portion side and pushing it in the direction of the larger diameter side. That is, when the body portion 6 of the shaft body 2 is press-fitted into the gripping portion 11 having an inner diameter narrower than the outer diameter while resisting the elasticity of the gripping portion 11 made of synthetic resin, the flange portion 4 of the shaft body 2 is pressed. While contacting the bottom surface of the recess 10 of the frame 3 and fitting into the interior of the recess 10, the annular projection 7 on the surface of the body 6 of the shaft body 2 exits the end surface on the large diameter side of the grip 11. Engage with the end face. As a result, the frame body 3 is engaged with the shaft body 2 in a state of being substantially sandwiched between the flange portion 4 of the shaft body 2 and the annular protrusion 7, so that the separation in the axial center direction is achieved. It can be effectively blocked.

  Next, the usage method of the formwork support 1 which concerns on this invention is demonstrated, referring FIG. 3 thru | or FIG. FIG. 3 is an explanatory view showing the state of use in the concrete formwork, and FIGS. 4 and 5 are explanatory views schematically showing the state when being pulled out from the surface of the casing after the formwork is removed. is there.

  The assembly of the concrete mold will be described with reference to the drawings with one side omitted. First, the female thread 5 that opens the male thread (not shown) formed at the end of the separator 15 to the end face on the small diameter side of the mold support 1. Threaded onto. Then, the male screw portion 9 protruding from the end face on the large diameter side of the mold support 1 is inserted into the through-hole 17 from the inside of the barrier plate 16, and the mold fastening rod 18 is inserted into the male screw portion 9 protruding outside the barrier plate 16. Screw in. At that time, on the outer surface of the dam plate 16, a vertical end thick 19 and a pair of horizontal end thick 20 are installed in an intersecting state on the outside, and a washer 21 is attached to the pair of horizontal end thick 20 while maintaining this state. The assembly on one side is completed by tightening the nut 22 screwed to the other end of the mold clamping cage 18. The same applies to the opposite side (not shown).

  Concrete is placed in the space between the dam plates 16 on both sides assembled in this way. After the concrete is solidified, for example, the lateral end 20 and the longitudinal end 19 are removed with the nut 22 loosened and the washer 21 retracted, or removed from the mold clamping bar 18 and then the lateral end. When the end material is removed by an appropriate procedure, such as removing the thick 20 and the vertical end thick 19 and finally the formwork clamping rod 18 is removed from the formwork support 1, the weir plate 16 is separated from the concrete surface. Mold to obtain a concrete structure.

  As shown in FIG. 4, the large-diameter side end face is exposed on the surface portion of the concrete 23 from which the barrier plate 16 has been removed while the frame body 3 portion of the mold support 1 is buried, and the shaft body 2 is further exposed. The male screw portion 9 protrudes from the surface. Then, in order to extract the formwork support 1 from the concrete 23, an appropriate removal tool such as a box wrench (not shown) is fitted to the square portion 8 of the shaft body 2 and rotated. In this case, in the mold support 1 that is used less frequently in the mold work, the outer peripheral surface of the frame body 3 is less damaged and the adhesion to the concrete 23 is small. Furthermore, the gripping force of the gripping part 11 is not so reduced. Under these circumstances, the frame 3 is rotated as a single body by the rotation of the shaft body 2, and the frame 3 is also made of the concrete 23 while the female screw portion 5 of the shaft body 2 moves away from the end of the separator 15. It can detach | leave from the concave hole surface and the mold support 1 can be extracted easily.

  However, in the mold support 1 in which the adhesion force of the frame body 3 to the surrounding concrete 23 increases as the number of times of use increases, the removal tool remains attached to the concrete 23 as shown in FIG. When the rotational force exceeds a predetermined value, only the shaft body 2 rotates, and idling occurs between the two. Then, when the shaft body 2 proceeds in a direction that even slightly removes from the separator 15, the flange portion 4 of the shaft body 2 that has been fitted into the recess portion 10 of the frame body 3 passes through the bottom surface of the recess portion 10 of the frame body 3. Will be pressed. At that time, the frame body 3 made of synthetic resin absorbs the displacement of the flange portion 4 within the elastic deformation range, and accordingly, an elastic repulsive force in the pulling direction is generated. Such an elastic repulsive force effectively acts on the outer peripheral surface of the frame 3, and as a result, the frame 3 is not easily attached to the concrete 23, and then the frame 3 is integrated with the shaft body 2. Since it rotates, the formwork support 1 can be pulled out without difficulty.

  Thus, even if it is a case where it uses repeatedly that an idling arises between the shaft 2 and the frame 3, it is provided in the trunk | drum 6 of the shaft 2 in the mold support 1 which concerns on this invention. The presence of the annular projection 7 makes it difficult for the frame body 3 to come off the shaft body 2, leading to improved durability compared to the conventional one. When this type of formwork support is screwed to the separator, it is easier to work between the shaft body 2 and the frame body 3 because it is easier to work by grasping the frame body portion and rotating the whole. It is desirable to ensure an appropriate gripping force that does not cause idling.

It is a fragmentary sectional view of the formwork support tool concerning the 1st example of the present invention. It is a side view of the same type frame support. It is explanatory drawing which showed the use condition of the same type frame support. It is explanatory drawing in the case of extracting the same frame support. Ru Figure der showing a state of use of the mold support member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Formwork support tool, 2 ... Shaft body, 3 ... Frame body, 4 ... Gutter part, 6 ... Trunk part, 7 ... Circular projection, 8 ... Square part, 9 ... Male screw part, 10 ... Recessed part, 11 ... Grasping part 12 ... Arc-shaped groove, 14 ... Rib, 15 ... Separator, 16 ... Dam plate, 18 ... Formwork clamp, 19 ... Vertical end thick, 20 ... Wide end thick, 21 ... Washer, 22 ... Nut, 23 ... concrete

Claims (1)

A metal threaded portion that penetrates the flange provided on the end surface on one end side to reach the inside of the substantially cylindrical body portion, and is formed of a metal in which a square portion and a male thread portion are sequentially formed on the other end side of the body portion. And a synthetic resin that is coaxial with the shaft body and is externally fitted to the body portion with the large-diameter side being the male screw portion side, and is engaged with the shaft body by a grip portion provided on the small-diameter side. An end portion of the separator by rotating a removal tool fitted to the square portion after removing a mold clamping rod screwed to the male screw portion of the shaft body. In the formwork support that is removed from the surface portion of the concrete housing by removing the female screw portion that is screwed into the frame body, the shaft body is inserted into the grip portion of the frame body from the male screw portion side. Locking portion comprising an annular protrusion that engages with the large-diameter side end surface of the gripping portion and resists separation in the axial direction of each other Provided in the body portion outer peripheral surface, the mold support member, characterized in that it is engaged idle possible to one another at a predetermined rotational force.

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