JP2000314172A - Pull-connection apparatus for concrete block - Google Patents

Abstract

PROBLEM TO BE SOLVED: To carry out pull-connection of both concrete blocks easily and at low costs. SOLUTION: Blocks 3, 3 are pulled and connected together by a connector 2 which comprises clamping bolts 13 to be screwed in respective inserts 12 which are buried in a block surface on a connecting side, and a connecting plate 15 connecting both the blocks together. Each clamping bolt 13 has a truncated cone 19 at a location between a screw shaft 16 and a bolt head 17. The connecting plate 15 has insertion holes 21, 21 into which the truncated cones 19 can be inserted, at both ends thereof. When the screw shaft 16 of the clamping bolt 13 is screwed into the insert 12 and clamped, a conical surface of the truncated cone 19 presses the external rim of the insertion hole 21, whereby the blocks are pulled together. When pulling operation is completed, a portion 29 of the circular cone frustum 19 closer to a minor diameter side is fitted into a reentrant 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a concrete block for connecting concrete blocks, such as a box culvert, a gutter block, an L-shaped retaining wall block, and the like. The present invention relates to a coupling device.

[0002]

2. Description of the Related Art When constructing a culvert, an open channel, or a retaining wall using a box culvert, a gutter block, or an L-shaped retaining wall block, it is necessary to closely connect the installation blocks to each other.

[0003] However, it is difficult to install the blocks at predetermined positions so that the blocks are brought into close contact with each other at the time of construction. Especially when the blocks are heavy products, such accurate positioning is required. Installation was more difficult.

Therefore, conventionally, a method has been adopted in which such blocks are provisionally installed in a state of being substantially abutted, and then the blocks are pulled together by using a fastener to be closely connected to each other. As this type of connecting means, for example, as shown in FIGS. 23 and 24, the angle members b, b are fixed at required positions on the connecting side of the blocks a, a to be connected (insert c and bolt d), the standing pieces e, e of these angle members b, b
In this case, the connection bolts g are inserted into the bolt holes f provided in the above, and are tightened with the nuts h.

[0005]

However, since this connection employs a means of tightening the nut h with respect to the connection bolt g, the vertical pieces e,
As shown by the dashed line in FIG. 23, a force is exerted to push and bend e, so that the drawing becomes unstable, and there is a problem that it is difficult to reliably draw the block.

SUMMARY OF THE INVENTION An object of the present invention is to provide a concrete block pulling connection device which can solve such a problem.

[0007]

In order to solve the above-mentioned problems, the present invention employs the following means. That is, the concrete block pulling connection device (hereinafter, referred to as a pulling connection device) according to the present invention is a concrete block pulling connection device for connecting concrete blocks to each other by pulling the blocks together using a connecting tool. An insert is buried in a bottom portion of a concave portion provided in the connection-side block surface portion. And the connecting tool is a tightening bolt screwed to the insert,
A connection plate for connecting the concrete blocks to each other, wherein the tightening bolt is provided with a truncated cone having a larger diameter on the bolt head side than on the screw shaft side between the screw shaft and the bolt head. In addition, insertion holes through which the truncated cone portion can be inserted are provided at both end portions of the connection plate, and a screw shaft portion of the tightening bolt is passed through the insertion hole and screwed into the insert to be screwed. Along with the tightening, the large-diameter end of the conical surface approaches the connection plate while the conical surface of the truncated cone portion presses the outer edge of the insertion hole in the length direction of the connection plate. When the concrete block to be drawn is drawn and the drawing is completed, a portion on the small diameter end side of the truncated cone is inserted into the recess.

Another aspect of the drawing connecting device according to the present invention is a concrete block drawing connecting device for connecting concrete blocks to each other by pulling the blocks together by using a connecting tool, wherein the concrete block drawing connecting device is provided on the connecting side of both concrete blocks. A concave portion is provided in the block surface portion. The connecting tool includes a tightening bolt and a connecting plate that connects the concrete blocks to each other. The tightening bolt is located between the screw shaft and the bolt head, and the bolt head is closer to the screw shaft than the screw shaft. There is a large diameter truncated cone,
In addition, insertion holes through which the truncated cone portion can be inserted are provided at both end portions of the connection plate, and a screw shaft portion of the tightening bolt is provided with the insertion hole and a bolt hole formed at a bottom portion of the recess. And screwed into a nut attached to a surface portion of the concrete block opposite to the block surface portion, and as the tightening bolts are tightened, the conical surface of the truncated cone portion becomes the insertion hole. While pressing the outer edge in the longitudinal direction of the connecting plate, the large-diameter end of the conical surface approaches the connecting plate, and accordingly, the concrete block to be connected is drawn, and in a state where the drawing is completed. The small-diameter end portion of the truncated cone portion is configured to enter the recess.

Another aspect of the drawing and connecting device according to the present invention is a concrete block drawing connecting device for connecting concrete blocks to each other by pulling the blocks together by using a connecting tool. A concave portion is provided in the block surface portion. The connector includes a screw shaft protruding from a bottom portion of the recess, a tightening nut that can be screwed to the screw shaft, and a connecting plate that connects the concrete blocks to each other. A truncated cone portion having a smaller diameter on the side near the bottom portion of the concave portion is provided, and an insertion hole through which the truncated cone portion can be inserted is provided at both end portions of the connection plate, As the screw shaft portion is screwed into the tightening nut through the insertion hole and the tightening nut is tightened, the conical surface of the truncated cone portion is located outside the insertion hole in the length direction of the connection plate. While pressing the edge of the conical surface, the large-diameter end of the conical surface approaches the connecting plate, along with which the concrete block to be connected is drawn, and in the state where the drawing is completed, the small-diameter end side of the truncated cone portion is Part before It is characterized in that configured in such a manner as to enter the recess.

Another aspect of the drawing connecting device according to the present invention is a drawing connecting device for a concrete block for connecting concrete blocks to each other by drawing a block using a connecting tool. A concave portion is provided in the block surface portion. Then, the connecting tool can screw a bolt insertion hole provided in a bottom portion of the concave portion into a screw shaft portion of the bolt inserted through a surface portion of the concrete block facing the block surface portion and projecting into the concave portion. A tightening nut and a connecting plate connecting the concrete blocks to each other, wherein the tightening nut is provided with a truncated cone having a smaller diameter on a side closer to a bottom portion of the concave portion; and both ends of the connecting plate. An insertion hole through which the truncated cone portion can be inserted is provided in the portion, and the screw shaft portion is passed through the insertion hole, screwed into the tightening nut, and tightened with the tightening nut. The large-diameter end of the conical surface approaches the connection plate while the conical surface of the portion presses the outer edge of the insertion hole in the length direction of the connection plate, and accordingly, the concrete block to be connected. It is drawn in a state where the drawn has been completed, and is characterized in that the small diameter end portion of the frustoconical portion is configured so as to enter into the recess.

In each of the pulling connection devices described above, the connection plate is formed so as to protrude toward the block surface portion at a peripheral portion of the insertion hole to form a protrusion, and only at a tip end surface of the protrusion. It is preferable that the connecting plate is configured to contact the block surface. Or,
It is preferable that the concave portion is provided on the distal end surface of the protrusion protruding from the block surface portion, and the connecting plate abuts on the block surface portion only at the distal end surface of the protrusion.

In each of the pulling connection devices, it is preferable that a front side corner of an outer edge of the insertion hole in the length direction of the connection plate is in contact with the conical surface in a point contact state.

In each of the pulling connection devices, it is preferable that the insertion hole is a circular hole, and a diameter thereof is equal to or larger than a diameter of a large diameter end of the truncated conical portion. .

[0014]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 4, a drawing connecting device 1 according to the present invention uses a connecting tool 2 to connect concrete blocks 3, 3 as, for example, U-shaped grooves by block drawing. In the present embodiment, positioning recesses 7, 7 for fitting a substantially half-length portion 6 of a connecting plate 15, which will be described later, in the block surface portions 5, 5 on the connecting side of the concrete blocks 3, 3. , Are provided in a state of being opened at the block connecting surfaces 9, 9,
On the bottom surface of the positioning recess 7, there is provided a conical recess 11 whose diameter decreases toward the recess bottom surface 10, and an insert 12 is embedded in the bottom portion of the recess 11.

The connecting member 2 includes a tightening bolt 13 screwed to the insert 12 and a connecting plate 15 connecting the concrete blocks. As shown in FIGS. 1, 3, and 6, the tightening bolt 13 has a conical shape in which the bolt head side has a larger diameter than the screw shaft side between the screw shaft part 16 and the bolt head part 17. A base 19 is provided. The length L (FIG. 3) of the inclined surface of the truncated cone portion 19 is set as required in consideration of the stroke required for drawing the concrete blocks between each other. A flange 20 is provided around the large diameter end of the truncated cone 19.

In this embodiment, the connecting plate 15 is formed of a rectangular plate-shaped steel plate, and has a diameter at both ends thereof equal to the diameter of the large diameter end of the truncated cone. Circular insertion holes 21 and 21 are provided.

The manner of connecting the concrete blocks 3 with each other using the connecting device 1 will be described below with reference to FIGS. First, another concrete block 3b to be connected to a certain concrete block 3a is placed on a foundation in a substantially approximated state, and the connecting plate 15 is positioned as shown in FIG. Fit into the recesses 7,7. By this fitting, the height of the concrete blocks 3 and 3 in the vertical direction is naturally determined to a predetermined value.

Thereafter, the insertion holes 21 and 21 provided at both ends of the connecting plate 15 are inserted into the corresponding inserts 12 and
After the concrete block is appropriately moved so as to be positioned at the position 12 (for example, after the block connecting surfaces 9, 9 of the concrete block are brought into an approaching state in which an interval of about 10 mm is generated), the insertion holes 21, 21 are formed. The screw shaft portions 16 of the tightening bolts 13, 13 passed through the screw holes are screwed to the corresponding inserts 12, 12. In the present embodiment, an elastic waterproofing member 22 is attached to the block connecting surface 9a of one concrete block.

Thereafter, the screw shaft portion 16 of the tightening bolt 13 inserted through the insertion hole 21 of the connecting plate 15 is screwed into the insert 12, and a tool is mounted on the bolt head 17 to tighten the tightening bolt 13. tighten.

FIG. 5 shows a state at the start of the tightening.
As shown in (A), the small-diameter edge 25 of the conical surface 23 of the truncated cone portion 19 or a portion in the vicinity thereof contacts the front side corner 27 of the outer edge of the insertion hole 21 in a substantially point contact state. ing.
When the tightening bolt 13 is tightened in this state,
Since the distance between the front side corners 27 of the insertion holes 21 and 21 is fixed, as shown by the arrow in FIG. 5B, the tightening bolt 13 connects the insertion hole 21 to the inner end thereof. It moves relatively toward the side, and the concrete block with less resistance is drawn toward the other concrete block. Normally, an existing concrete block is already fixed to another existing concrete block, so that it does not move, and the newly installed concrete block is attracted.
Finally, as shown in FIG. 5C, the portion 29 on the small diameter end side of the truncated cone 19 enters the recess 11. Concrete blocks 3, 3
As a result, the elastic water-stopping material 22 is compressed, and the connection between the blocks 30 (FIGS. 2 and 4) is secured. In FIG. 5C, in the final connection state of the concrete block, the flange portion 20 provided around the large-diameter end of the truncated cone portion 19 is in contact with the surface 31 of the connection plate. .

When the tightening bolt 13 is tightened, as shown in FIG. 6, the front side corner 27 (FIG. 5) of the outer edge of the insertion hole draws a spiral shape 28 on the conical surface 23. Since the front side corners 27 are in contact with each other, there is no possibility that the front side corners 27 will bite into the conical surface 23, the tightening of the tightening bolts 13 can be performed smoothly, and the block can be pulled smoothly without fail.

[Other Embodiments] FIGS. 7 and 8 show another embodiment of the pull-in connection device 1 according to the present invention.
Instead of screwing the screw shaft portion 16 of the tightening bolt 13 into which the 1 has been inserted and screwing it into the insert as described above, a bolt hole 32 provided in the bottom portion of the concave portion 11 is inserted.
The concrete block 3 is configured to be screwed and fastened to a nut 35 provided on a surface portion 33 of the concrete block 3 on the side facing the block surface portion 5. Also in the case of such a configuration, by tightening the tightening bolt 13 in the same manner as described above, finally, the truncated cone portion 1 of the tightening bolt 13
The portion 29 on the small diameter end side of 9 enters the concave portion 11, and as shown in FIG. 8, the concrete blocks 3 and 3 are connected by drawing.

FIGS. 9 to 10 and FIGS. 11 to 12 show a case in which the truncated cone portion 19 is provided on the tightening nut 36, and the tightening nut is attached to the screw shaft portion 16 protruding from the block surface portion 5. By screwing and tightening the nut 36,
Eventually, the small-diameter end portion 29 of the truncated cone portion 19 of the tightening bolt 13 enters the concave portion 11, and as shown in FIGS. It will be connected by pulling. 9 to 10, the screw shaft portion 16 is implanted in the block surface portion 5, and in FIGS.
The bolt 39 inserted into the insertion hole 37 at the surface portion 33 of the concrete block 3 facing the block surface portion 5 is formed as a screw shaft projecting portion projecting from the recess 11.

The form of the concave portion provided in the block surface portion on the connection side of the concrete block may be a portion 2 on the small diameter end side of the truncated cone portion 19 of the tightening bolt 13 or the tightening nut 36.
Any form can be used as long as it can insert 9.

Insertion hole 21 provided in connection plate 15
Is not limited to a circular hole, as long as the conical surface of the truncated cone of the tightening bolt or tightening nut can press the outer edge of the insertion hole in the length direction of the connecting plate. It may be a hole or the like.

In a state where the concrete block is drawn and connected as required, the large-diameter end portion 40 of the truncated conical portion 19 of the tightening bolt 13 or the tightening nut 36 is, as shown in FIGS. Connection plate 15
May be removed from the insertion hole 21 provided in the first position.
FIG. 14 shows a case where the height H of the truncated cone 19 is set to be larger than that in FIG. In this connection state, the portion 29 on the small diameter end side of the truncated conical portion 19 has entered the concave portion 11.

FIG. 15, FIG. 16 and FIG. 17 (A) show another embodiment of the pull-in connection device 1 according to the present invention, in which the peripheral portion of the insertion hole 21 of the connection plate 15 is the block surface portion 5. The connecting plate 15 is configured to contact the block surface 5 only at the tip end surface 42 of the projecting portion 41. In FIG. 15, the protrusion 41 is provided as shown in FIG.
As shown in FIG. 2, the projection is formed to project annularly toward the block surface portion 5. Also, in FIG. 16, as shown in FIG. 19, it is configured to protrude in a rectangular shape, and both are formed by, for example, press working. The protruding portion 41 is constituted by a separate washer-like member 43 as shown in FIG. 17 (B) in FIG. 17 (A). The projection 41 may be formed by fixing the washer 43.

When the projecting portion 41 is configured as described above,
The contact area between the connecting plate 15 and the block surface portion 5 can be considerably reduced as compared with the cases shown in FIGS. 3 to 4, 7 to 8, 9 to 10, and FIGS. The frictional resistance caused by the relative sliding between the connecting plate 15 and the block surface portion 15 can be reduced, and the operation of drawing the block by tightening the tightening bolts 13 can be smoothed.

The same effect can be achieved by the pull-in connection device 1 shown in FIGS. in this case,
The concave portion 11 is recessed at the distal end surface 45 of, for example, a circular projection 44 provided on the block surface portion 5, and the connecting plate 15 is configured to contact the block surface portion 5 only at the distal end surface 45. I have. Thereby, it is possible to reduce the frictional resistance caused by the relative sliding between the connecting plate 15 and the block surface portion 5 which is generated when the block is drawn.
This makes it possible to smooth the block drawing operation by tightening the tightening bolts 13.

[0030]

The present invention has the following excellent effects. When the pulling connection device according to the present invention is used, the conical surface of the truncated cone portion is tightened by the tightening bolt or the tightening nut, so that the outer edge of the insertion hole provided in the connecting plate in the length direction of the connecting plate. The concrete block exerts an effect of moving the concrete block by pressing the concrete block, so that the concrete blocks can be pulled together and connected without difficulty. Thus, when the concrete block is pulled, as in the case where the conventional angle member is connected with the connection bolt and the nut, there is a problem that the pulling force of the standing piece of the angle member is exerted and unstable pulling is performed. There is an advantage that the block can be reliably and easily drawn without any occurrence.

In the present invention, a concave portion is provided in the block surface portion on the connection side of the concrete block to allow the small-diameter end portion of the truncated cone to enter.
The length of the inclined surface of the truncated cone can be set as long as possible while the thickness of the connection plate is reduced. Therefore, according to the present invention, as long as the connecting plate has a tensile strength that can withstand pulling of the concrete block, the connecting plate can be formed as thin as possible. The economy which does not need to be obtained is obtained, and the drawing connection device can be constructed inexpensively. If the same amount of pulling as shown in the above embodiment is to be ensured without providing a concave portion on the concrete block side, the thickness of the connecting plate 15 must be increased as shown in FIG. Alternatively, it is necessary to perform a special process for increasing the thickness of the peripheral portion of the insertion hole.

In particular, the insertion hole provided in the connection plate is
When forming as a common circular hole that is easy to process,
Since the processing is easy, the production cost can be reduced from this point as well. When the diameter of the circular hole is set to be substantially equal to or larger than the diameter of the large diameter end of the truncated conical portion, the block is drawn sufficiently by making the most of the diameter of the insertion hole. You will get.

By setting the length of the conical surface of the truncated cone portion of the tightening bolt or the tightening nut as required,
It is possible to secure a desired amount of drawing of the block.

The insertion hole provided in the connection plate,
When the front side corner of the outer edge in the length direction of the connection plate is configured to contact the conical surface in a point contact state, the front side corner comes into contact with the conical surface in a spiral shape. For this reason, there is an advantage that the edge of the insertion hole does not bite into the conical surface, the bolt can be smoothly tightened, and the block can be pulled smoothly without fail.

[0035] In particular, in the pulling connection device according to the present invention, the connection plate protrudes toward the block surface portion at a peripheral portion of the insertion hole, and the connection plate is provided only at a front end surface of the protrusion. The block is configured to be in contact with the block surface, or the recess is formed in the distal end surface of a protrusion that protrudes from the block surface, and the connection plate contacts the block surface only at the distal end surface of the protrusion. In the case where the connecting plate and the block surface are in contact with each other, the contact area between the connecting plate and the block surface can be reduced, and the frictional resistance caused by relative sliding between the connecting plate and the block surface generated when the block is drawn can be reduced. Therefore, the operation of drawing the block by tightening the tightening bolts can be smoothed.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view illustrating a pull-in connection device.

FIG. 2 is a perspective view showing a state where blocks are drawn and connected.

FIG. 3 is a cross-sectional view illustrating an initial stage of block drawing.

FIG. 4 is a cross-sectional view showing a state where blocks are drawn together and connected.

FIG. 5 is an explanatory diagram illustrating a drawing action of a block accompanying tightening of a tightening bolt.

FIG. 6 is a perspective view showing a tightening bolt together with an operation at the time of tightening;

FIG. 7 shows another embodiment of the pulling connection device according to the present invention.
It is sectional drawing shown in the initial stage of block attraction.

FIG. 8 is a cross-sectional view showing a state where blocks are connected to each other by drawing using the connecting device.

FIG. 9 is a cross-sectional view showing another aspect of the pulling connection device according to the present invention at an initial stage of block pulling.

FIG. 10 is a cross-sectional view showing a state in which blocks are connected by drawing using the connecting device.

FIG. 11 is a cross-sectional view showing another mode of the pulling connection device according to the present invention at an initial stage of block pulling.

FIG. 12 is a cross-sectional view showing a state where blocks are connected to each other by drawing using the connecting device.

FIG. 13 is a sectional view showing another aspect of the final tightening state of the tightening bolt.

FIG. 14 is a sectional view showing another aspect of the final tightening state of the tightening bolt.

FIG. 15 is a cross-sectional view showing another embodiment of the drawing connection device according to the present invention in a state where the blocks are connected by drawing.

FIG. 16 is a cross-sectional view showing another embodiment of the drawing connection device according to the present invention in a state where blocks are connected by drawing.

FIG. 17 is a cross-sectional view showing another mode of the pulling connection device according to the present invention in a state where the blocks are connected by pulling.

FIG. 18 is a perspective view showing an example of a protruding portion provided on a connection plate.

FIG. 19 is a perspective view showing another aspect of the protrusion provided on the connection plate.

FIG. 20 is an exploded perspective view for explaining another mode of the pulling connection device according to the present invention.

FIG. 21 is a cross-sectional view showing a state in which blocks are connected by drawing using the drawing connecting device shown in FIG. 20;

FIG. 22 is a cross-sectional view explaining a problem when a concave portion is not provided in a block.

FIG. 23 is a cross-sectional view illustrating a conventional block pulling connection device.

FIG. 24 is a cross-sectional view illustrating a block connecting state using the connecting device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pull-in connection device 2 Connecting device 3 Concrete block 5 Block surface part 11 Concave part 12 Insert 13 Tightening bolt 15 Connection plate 16 Screw shaft part 17 Bolt head 19 Conical part 21 Insertion hole 23 Conical surface 27 Front side corner part 29 Conical part 29 Conical part 35 Nut 36 Tightening nut 39 Bolt 41 Projection 42 Tip surface 43 Projection 45 Tip surface

Claims (8)

[Claims] 1. A concrete block pulling connecting device for connecting concrete blocks by pulling the blocks together by using a connecting tool, wherein an insert is provided at a bottom portion of a concave portion provided on a block surface portion on a connecting side of both concrete blocks. Embedded, wherein the connecting tool comprises a tightening bolt screwed into the insert, and a connecting plate connecting the concrete blocks, the tightening bolt is provided between a screw shaft portion and a bolt head. ,
A frusto-conical portion whose bolt head side is larger in diameter than the screw shaft portion side is provided, and insertion holes through which the frusto-conical portion can be inserted are provided at both end portions of the connection plate, As the screw shaft of the bolt is screwed into the insert through the insertion hole and tightened, the conical surface of the truncated cone presses the outer edge of the insertion hole in the length direction of the connection plate. While the large-diameter end of the conical surface approaches the connecting plate, the concrete block to be connected is drawn along with the connecting plate, and in the state where the drawing is completed, the small-diameter end side portion of the truncated cone portion becomes the concave portion. A pull-in connection device for a concrete block, characterized in that the device is configured to enter the concrete block. 2. A concrete block pulling connecting device for connecting concrete blocks to each other by pulling the blocks together by using a connecting tool, wherein a concave portion is provided in a block surface portion on a connecting side of both concrete blocks, The tool comprises a tightening bolt and a connection plate that connects the concrete blocks, wherein the tightening bolt is located between the screw shaft and the bolt head.
A frusto-conical portion whose bolt head side is larger in diameter than the screw shaft portion side is provided, and insertion holes through which the frusto-conical portion can be inserted are provided at both end portions of the connection plate, The screw shaft of the bolt is inserted through the insertion hole and the bolt hole provided at the bottom of the recess, and screwed to a nut attached to a surface of the concrete block facing the block surface. As the tightening bolts are tightened, the conical surface of the truncated cone presses the outer edge of the insertion hole in the length direction of the connection plate, and the large-diameter end of the conical surface is connected to the connection plate. , The concrete block to be connected is drawn together, and in the state where the drawing is completed, the small-diameter end side portion of the truncated cone portion is configured to enter the concave portion. Attracted coupling device of emissions cleat block. 3. A concrete block pulling connecting device for connecting concrete blocks by pulling the blocks together by using a connecting tool, wherein a concave portion is provided in a block surface portion on a connecting side of both concrete blocks, The fixture includes a screw shaft protruding at a bottom portion of the concave portion, a tightening nut capable of being screwed to the screw shaft, and a connection plate connecting the concrete blocks to each other. A truncated cone portion having a smaller diameter is provided on the side closer to the bottom portion of the concave portion, and at both end portions of the connection plate, insertion holes through which the truncated cone portion can be inserted are provided, and the screw shaft portion is provided. As the screw is screwed into the tightening nut through the insertion hole and the tightening nut is tightened, the conical surface of the truncated cone portion is formed in the insertion hole.
While pressing the outer edge in the length direction of the connecting plate, the large-diameter end of the conical surface approaches the connecting plate, and accordingly, the concrete block to be connected is drawn, and in a state where the drawing is completed, the cone is closed. A drawing block connecting device for a concrete block, wherein a portion on a small diameter end side of a base portion is configured to enter the concave portion. 4. A concrete block pulling connection device for connecting concrete blocks to each other by pulling the blocks together by using a connecting tool, wherein a concave portion is provided in a block surface portion on a connection side of both concrete blocks, A fastening nut capable of screwing a bolt insertion hole provided in a bottom portion of the concave portion to a screw shaft portion of the bolt inserted through a surface portion of the concrete block facing the block surface portion and projecting from the concave portion. And a connecting plate for connecting the concrete blocks to each other, wherein the tightening nut is provided with a truncated cone having a smaller diameter on the side closer to the bottom of the recess, and at both end portions of the connecting plate. An insertion hole through which the truncated cone portion can be inserted is provided, and the screw shaft portion is passed through the insertion hole and screwed into the tightening nut. As the tightening nut is tightened, the large-diameter end of the conical surface approaches the connection plate while the conical surface of the truncated cone presses the outer edge of the insertion hole in the length direction of the connection plate. Accordingly, the concrete block to be connected is drawn, and in the state where the drawing is completed, the portion on the small diameter end side of the truncated cone portion is configured to enter the concave portion. apparatus. 5. The connecting plate has a projecting portion formed by projecting a peripheral portion of the insertion hole toward the block surface portion, and the connecting plate is connected to the block surface portion only at a tip end surface of the projecting portion. The drawing block connecting device for a concrete block according to any one of claims 1 to 4, which is in contact with the block. 6. The concave portion is formed in the distal end surface of a protrusion protruding from a block surface portion, and only at the distal end surface of the protrusion.
The pulling connection device for a concrete block according to any one of claims 1 to 4, wherein the connection plate is in contact with the block surface portion. 7. The conical surface according to claim 1, wherein a front side corner of an outer edge of the insertion hole in a length direction of the connection plate is in point contact with the conical surface. Concrete block pulling coupling device. 8. The method according to claim 1, wherein said insertion hole is a circular hole, and a diameter thereof is substantially equal to or larger than a diameter of a large diameter end of said truncated cone portion. The concrete block pulling connection device according to any one of the above.