JPH0594514U - Anchor for concrete - Google Patents

Abstract

(57) [Summary] [Purpose] To improve the workability, handleability, and pull-out strength of a concrete anchor having a cylindrical wedge that locks into the mounting hole at the tip of the anchor body made of deformed steel bar. [Structure] An anchor body 1 is formed by forming a conical widening portion 3 having a smaller diameter at the base end toward the tip and having a larger diameter toward the tip, and a remaining portion 4 of a deformed steel bar at the tip. A tubular wedge 11 having a plurality of split grooves 12 at the tip end and a claw piece 13 opened toward the base end at the base end was fitted into the expansion part. .. The whole has a substantially uniform diameter, and the claw piece 13 of the cylindrical wedge 11 bites into the hole wall to increase the fixing force.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an anchor for concrete which is used as a reinforcing material at a joint portion of a new concrete structure such as raising the existing concrete structure, adding reinforcing columns and partition walls, and building blocks.

[0002]

[Prior Art]

 The tip of the existing concrete structure is inserted into the mounting hole and has a cylindrical wedge that acts as a retaining member, and the part that projects from the mounting hole and is embedded in the new concrete structure functions as part of the reinforcing bar that is the concrete reinforcement. Anchors for concrete, which are composed of deformed steel bars, are known.

One of the known anchors for deformed steel bar concrete is shown in FIG. 5, in which the base end of the anchor main body 51 is made by hot forging to the tip of an anchor main body 51 made of deformed steel bar of a predetermined length. A sleeve (cylindrical wedge) 53 having a plurality of split grooves 54 extending from the tip to the base end is formed in the anchor body 51. There is one that is fitted from the base end to the expanded portion 52.

Further, as shown in FIG. 6, a base of a sleeve (cylindrical wedge) 63 having a screw 62 formed at the tip of an anchor body 61 and having a plurality of split grooves 64 extending from the tip toward the base. There is also one in which the end is screwed into the screw 62 and the conical expanding portion piece 65 is fitted into the sleeve 63 from the tip side.

[0007] These holes are installed in an existing concrete structure, inserted into the holes, and then the sleeves 53 and 63 are expanded by the expansion part 52 or the expansion part piece 65 so that the holes are made to stick. It is something that is fixed.

[0006] However, in these conventional anchors for concrete, the outer diameter of the sleeve that functions as a retaining member is larger than the outer diameter of the deformed steel bar, so that the mounting hole also has a diameter equal to or larger than that of the sleeve. Since it takes longer time and more power is consumed by the drill driving tool compared to the case of drilling a steel bar with the same outer diameter as the deformed steel bar, it is necessary to work when installing a large number. It is disadvantageous in terms of efficiency and work cost.

[0007] Further, these concrete anchors have a large diameter at the tip end due to the sleeve, and therefore, for example, when packing a large number of them, they tend to be bulky, and it is difficult to arrange them in a stable state. It is inconvenient in terms of transportation and storage because it is necessary to reduce the number or shift the position of the tip or reverse part of the tip.

Further, these anchors for concrete have a structure in which the tip side of the sleeve is expanded so that the tip has a large diameter and sticks to the hole wall, so that the sleeve surface has a hole wall surface when pulling load acts. Not only is it more likely to slip along, and the sleeve moves with the anchor body and locks at a position that is considerably shallower than the initial installation location, which reduces the cone-like fracture strength of the concrete, which is not only inconvenient. Even with a relatively small pulling load, it may be completely pulled out.

[0009]

[Problems to be solved by the device]

 The problems to be solved by the present invention are disadvantageous in terms of work efficiency and work cost of the conventional anchor for concrete having an expansion sleeve at the tip of the deformed steel bar, and are inconvenient in transportation and storage. However, the reliability with respect to the pulling load is not sufficient.

[0010]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the present invention provides a short deformed steel bar at the tip of an anchor body made of deformed steel bar with a base end having a smaller diameter than that of the anchor body and a conical widened part having a larger diameter toward the tip. The outer diameter is equal to or slightly smaller than the outer diameter of the anchor body and has a plurality of split grooves extending from the tip edge toward the base end, and is formed outwards toward the base end. A cylindrical wedge having a claw piece that is bent and protruded to the outside of the anchor body at the base end is fitted into the expansion portion.

[0011]

[Action]

 An existing concrete structure is provided with a mounting hole with a diameter equal to or slightly larger than the outer diameter of the anchor body, and the base end face is hammered and hammered into the mounting hole from the tip. When the driving is finished, the claw piece sticks to the hole wall and the tubular wedge is fixed. By slightly pulling the anchor body, the expansion part pushes the tip end of the cylindrical wedge and sticks it to the hole wall. That is, the anchor is fixed by the tab piece and the expanded portion sticking to the hole wall.

[0012]

【Example】

 An embodiment of the present invention will be described with reference to the drawings. In FIG. 1, a tip portion of an anchor body 1 made of a deformed steel bar having a predetermined length is provided with a shaft portion 2 having a smaller diameter than that and a large diameter toward the tip. And a conical widened portion 3 that is formed in a continuous manner, and a deformed steel bar portion remains at the tip of the widened portion 3 with a short length 4. Further, the base end of the shaft portion 2 forms a step portion 5 perpendicular to the central axis.

As shown in FIG. 2, the cylindrical wedge 11 has a rectangular metal plate provided with three split grooves 12 extending appropriately from the leading edge to the proximal end and having a notch at the proximal end. A cylinder having two claws 13 provided thereon is rolled into a cylindrical shape by covering the shaft 2 and the expanding portion 3, and the outer diameter thereof is the outer diameter of the anchor body 1, that is, the axial direction of the deformed steel bar. It is equal to or slightly smaller than the maximum diameter that includes the extending ribs and the circumferential ridges. Further, the both side edge joints of the metal plate and the split groove 12 are arranged at substantially equal intervals in the circumferential direction, and the claw piece 13 is bent outward toward the base end at a position symmetrical with respect to the axis and protrudes outward from the anchor body 1. Has been made.

In the present embodiment having such a configuration, since the cylindrical wedge 11 has substantially the same diameter as the anchor body 1, a large number of parallel wedges can be aligned in parallel with each other with almost no gap and stably bundled for transportation. Not only is it convenient for storage, but it also has a high work efficiency and power consumption of the drill-driving tool because the attachment holes drilled in the existing concrete structure need only be the same diameter as the anchor body 1 or slightly larger than this. The amount may be small.

FIG. 3 shows a state of being fixed in the mounting hole, in which a mounting hole 22 having a diameter equal to the outer diameter of the anchor body 1 and a predetermined depth is drilled in the existing concrete structure 21, The base end surface of the anchor body 1 is hammered and hammered until it almost reaches the bottom of the hole, and is fixed by the claw piece 13 of the cylindrical wedge 11 and the expanded tip end portion.

That is, when the driving is finished, the claw piece 13 of the tubular wedge 11 that has moved integrally with the anchor body 1 by hitting the step 5 until the proximal edge spreads outward due to its elasticity. Since it sticks to the wall to fix the tubular wedge 11, the expansion body 3 pushes the tip portion of the tubular wedge 11 divided by the split groove 12 by pulling the anchor body 1 slightly toward the proximal end. It will be attached to the hole wall. At this time, even if the cylindrical wedge 11 may move toward the base end, the claw piece 13 that is bent outward toward the base end bites into the hole wall, and its movement is very small. It will be fixed firmly just by pulling it out a little from the position, and the cone breaking strength will not be reduced.

In this case, when the remaining portion 4 of the deformed steel bar formed at the tip of the expanded portion 3 enters the tip portion of the tubular wedge 11, the ribs and the bushes at that portion further push and spread it further. Coercive force increases step by step.

The portion protruding from the mounting hole 22 of the anchor body 1 functions as a part of the reinforcing bar of the new concrete structure, and is firmly fixed to the existing concrete structure, so that the new concrete structure can be stably maintained. To join.

Next, the test results comparing the pulling performance of the present invention product and the conventional product will be described. The deformed bars each have an outer diameter (maximum diameter) of 10 mm, and the product of the present invention shown in FIG. 1 in which a cylindrical wedge having an outer diameter of 10 mm is fitted is installed in a mounting hole having a diameter of 10 mm and a depth of 60 mm. Inserted up to. Further, the conventional product shown in FIGS. 5 and 6 to which a sleeve having an outer diameter of 14 mm and 5 mm was attached was inserted into a mounting hole having a diameter of 14 mm and a depth of 50 mm up to the hole bottom. When a pulling load was applied to these anchor bodies and the pulling amount was measured, the results shown in FIG. 4 were obtained.

The curve A in FIG. 4 shows the product of the present invention, and shows a maximum pull-out load of about 1,9 tf when pulled out by about 4, 5 mm. Curve B is the conventional product shown in FIG. 5 and shows a maximum drawing load of about 1.6 tf when drawn about 6 mm. The curve C is the conventional product shown in FIG. 6 and shows the maximum pulling load of about 1.6 tf when pulled out by about 9 mm. From these, it is confirmed that the concrete anchor according to the present invention is firmly fixed by pulling out a little.

[0021]

[Effect of the device]

 As is clear from the above, according to the concrete anchor of the present invention, since the whole has a substantially uniform diameter, the mounting hole drilling work can be performed efficiently and economically, and is convenient for transportation and storage. .. Also, with the cylindrical bush, the claw pieces at the base end bite into the hole wall and are prevented from moving in the pulling out direction.Therefore, just by slightly pulling the anchor body, the expanded part and the deformed steel bar remaining part at the tip end Is greatly expanded, and it can be firmly fixed in cooperation with the claw piece at the deep position of the mounting hole.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view showing an embodiment of the present invention.

FIG. 2 is a developed front view of a cylindrical wedge.

FIG. 3 is a front partial view showing a state where the embodiment of FIG. 1 is fixed in a mounting hole.

FIG. 4 is a graph showing the relationship between the withdrawal load and the withdrawal amount of the present invention product and the conventional product.

FIG. 5 is a partially cutaway front view of a conventional example.

FIG. 6 is a partially cutaway front view of another conventional example.

[Explanation of symbols]

1 anchor body, 3 expansion part, 4 remaining part, 11 cylindrical wedge, 12 split groove, 13 claw pieces,

Claims (1)

[Scope of utility model registration request] 1. An anchor body made of deformed steel bar is formed at the tip end thereof with a conical widened portion whose base end has a diameter smaller than that of the anchor body and becomes larger toward the tip, leaving a short deformed steel bar portion at the tip. The outer diameter is equal to or slightly smaller than the outer diameter of the anchor body, and has a plurality of split grooves at the distal end extending from the distal edge toward the proximal end, and is bent outward toward the proximal end. An anchor for concrete in which a cylindrical wedge having a claw piece projecting to the outside of the main body at the base end is fitted in the expanding portion.