JPH0524725Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention mainly relates to anchors that are embedded in foundations such as concrete walls and floors. The present invention relates to an anchor suitable for being embedded in a hole having a relatively nearly perfect circular cross-sectional shape.

[Conventional technology]

For foundations such as concrete floors and walls
When installing equipment such as OA equipment or panels, anchors are often embedded in the base in advance and the equipment is fixed to the anchors. In order to embed an anchor, it is first necessary to drill a hole in the base using a drilling device, but drilling work in a room where other equipment or equipment, such as OA equipment, is already installed, is difficult.
The effects of vibration and dust on such equipment must be considered.

Therefore, conventionally, drilling work in such places has often been performed using a drilling device using a diamond core bit, which generates relatively little vibration and dust. A drilling device using this diamond core bit is made by brazing a chip containing diamond powder to the tip of a cylindrical body, and the drilling body is rotated by a drive device, which guides the drilling to the desired location. A predetermined hole is drilled by rotating and pressing the blade. In addition, crushed concrete and the like generated during drilling are sucked up by a hose or the like through the inside of the blade to prevent dust from scattering around.

Holes drilled using a drilling device that uses such diamond core bits are evenly ground by the sharp cutting edge provided at the cylindrical tip, making it easier to drill holes than other drilling devices such as drills. , its cross-sectional shape is close to a perfect circle.

On the other hand, so-called screw-in anchors are often used as anchors to be embedded in holes because of their ease of construction. This screw-in anchor is composed of a bolt, a cylindrical plug having a plurality of cuts in the axial direction from one end, and an expander having a tapered surface formed on the outer periphery. To embed this type of anchor, first insert the bolt into the plug from the other end of the plug, and connect the expanded part to the tip of the plug with a loose screw connection to the expanded part inserted from the notched end. and insert it into the hole. Then, when the bolt is screwed in, the expanded portion is drawn into the plug by the bolt, and the cut in the plug is expanded by the tapered surface of the expander. By expanding the plug, the anchor is brought into close contact with the peripheral wall of the hole and is firmly fixed.

[Problem that the invention attempts to solve]

However, when embedding such a conventional screw-in anchor into a hole with a relatively nearly perfect circular cross-sectional shape, such as one drilled using a drilling device using a diamond core bit, A phenomenon called "co-rotation" occurred, and screwing was often difficult or impossible.

To explain this co-rotation phenomenon in detail, when a bolt is screwed into an expanded part, the tapered surface of the outer periphery of the expanded part comes into close contact with the inner wall of the plug, preventing mutual rotation with the plug. ing. Therefore, if the cross section of the hole is not a perfect circle, the outer peripheral surface of the plug will catch on the inner wall of the hole and will not rotate, so even if the bolt is rotated, the expanded portion will not rotate and screwing can be performed. However, if the cross section of the hole is relatively close to a perfect circle, even if the outer diameter of the plug is made to approximately match the inner diameter of the hole and the anchor is inserted into the hole, it is difficult to expand the expanded portion while expanding the cut of the plug. Generally, it is difficult to prevent a large rotational torque when the plug is screwed to a bolt only by the frictional resistance between the rigid bodies between the outer circumferential surface of the plug and the inner wall of the hole. Therefore, when the bolt is rotated, the expanded portion and the plug rotate together, making it impossible to screw in the bolt.

SUMMARY OF THE INVENTION An object of the present invention is to solve these problems with conventional anchors and to provide an anchor that does not cause the co-rotation phenomenon even when embedded in a hole that is relatively close to a perfect circle.

[Means for solving problems]

The present invention comprises a bolt, a cylindrical plug in which a plurality of cuts are radially provided in the axial direction from only one end, and an expander having a tapered surface formed on the outer periphery, and one end of the plug In an anchor that screws together an expander inserted from one end and a bolt inserted from the other end, an annular groove is provided on the outer periphery of the plug, and an outer peripheral diameter larger than the maximum diameter of the outer periphery of the plug. The anchor is characterized in that a non-slip O-ring is fitted into the annular groove so that the annular groove is formed.

[Effect]

In the anchor of the present invention, when the bolt is rotated after being inserted into the hole and screwed into the expander, the plug and the Co-rotation of the expander in close contact with it is suppressed. Therefore, it can be suitably used for holes having a cross-sectional shape that is relatively close to a perfect circle.

〔Example〕

Next, embodiments of the present invention will be described based on the drawings.

FIG. 1 is a perspective view showing an example of the anchor of the present invention. The anchor 1 includes a bolt 2, a cylindrical plug 3 having an inner diameter through which the bolt 2 can be inserted, and an expander 4 that is threadedly connected to the bolt 2.

The bolt 2 consists of a hexagonal head 5 and a shaft body 6,
A plug 3 is attached to the shaft body 6 as will be described later.
The threaded portion is formed with a length that allows sufficient advancement to provide the required expansion.

The plug 3 is provided with a plurality of cuts 8 in the axial direction from one end 7 thereof, and the expander 4 is inserted into the plug 3 from the end 7 side. Note that the inner wall surface of the end portion 7 is formed with a tapered surface whose diameter increases toward the distal end in order to facilitate insertion of the expander 4. The other end 9 is an insertion opening for the bolt 2. A cut 8 is formed on the outer periphery of the plug 3 at a position where the plurality of cuts 8 are provided.
An annular groove 10 is provided in a direction perpendicular to the groove 1.
An O-ring 11 made of a material with a large surface frictional resistance coefficient, such as an elastic body such as rubber, is fitted into the O-ring 11. This annular groove 10 may be provided at a position closer to one end 7 than the position shown in FIG. 1, or conversely closer to the other end 9 where the cut 8 is not present.

The expander 4 is a cylindrical body with a tapered surface 12 formed on its outer periphery, and has an internal thread on its inner wall surface for threaded connection with the bolt 2.

Each of the parts constituting the anchor 1 is made of a rigid and strong material, such as a metal such as steel or an alloy, or a reinforced plastic material such as FRP. If necessary, the washer 13 and spring washer 14 as shown in Fig. 1 may be attached to the bolt 2.
May be used together.

Next, a method for embedding the anchor shown in FIG. 1 into a hole provided in a base will be explained with reference to FIGS. 2 and 3. FIG. 2 is a sectional view showing the state in which the anchor 1 is inserted into a hole 16 (the figure shows an example of a through hole, but the same applies to a hole with a bottom surface) provided in a concrete base 15. be. In the figure, reference numeral 17 indicates the base of equipment to be fixed to the base 15 by the anchor 1.

To bring the anchor 1 into the state shown in Figure 2, first,
After drilling a hole 16 in the base 15 with a drilling device, and then inserting a washer 13 and a spring washer 14 into the bolt 2, an annular groove 1 provided on the outer periphery of the washer 13 and a spring washer 14 are inserted into the bolt 2.
The bolt 2 is inserted into the plug 3 which has an O-ring 11 fitted therein, and the expander 4 is loosely screwed into the tip of the bolt 2. Next, the anchor 1 assembled in this manner may be inserted into the hole 16 of the base 15 through the through hole provided in the base 17.

Next, rotate bolt 2 strongly with a spanner, etc.
By deepening the screw connection with the expander 4, the expander 4 advances inside the plug 3 and expands the cut 8 thereof. As a result, the outer periphery of the plug 3 where the cut 8 exists is expanded, and the outer periphery of the plug 3 is pressed against the inner wall of the hole 16 and brought into close contact. At this time, since the plug 3 is restrained from rotating relative to the inner wall surface of the hole 16 due to the frictional resistance of the O-ring 11, the co-rotation phenomenon due to the rotation of the bolt 2 does not substantially occur. FIG. 3 shows a state in which the plug 3 is expanded in this manner and firmly and tightly fixed in the hole 16.

In the example shown in FIG. 1, an annular groove 10 is provided at the position of the cut 8 of the plug 3 and perpendicular thereto, so that the plug 3 expands in proportion to the progress of the expander 4 inside the plug 3. When opened, the outer diameter of the O-ring 11 is expanded accordingly, and the pressing force against the inner wall surface of the hole 16 is also increased. Therefore, the frictional force corresponding to the force required to screw in the bolt 2, which increases in proportion to the expansion of the plug 3, is automatically increased, so that the co-rotation phenomenon can be suppressed more effectively.

[Effect of idea]

By configuring the anchor of the present invention as described above, it does not rotate even in holes having a relatively close to perfect circular cross-sectional shape, such as those drilled by a drilling device using a diamond core bit. Can be embedded effectively.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an example of the anchor of the present invention, FIG. 2 is a sectional view showing the anchor shown in FIG. 1 inserted into a hole 16 provided in a base 15, and FIG. FIG. 3 is a sectional view showing a state in which the bolt 2 of the anchor is further screwed in, the plug 3 of the anchor is expanded, and the plug 3 of the anchor is tightly fixed in the hole 16; 1... Anchor, 2... Bolt, 3... Plug, 4... Expander, 5... Head, 6... Shaft, 7
... End, 8 ... Cut, 9 ... End, 10 ... Annular groove, 11 ... O-ring, 12 ... Tapered surface, 1
3...Washer, 14...Spring washer, 1
5...Base, 16...Hole, 17...Base.

Claims (1)

[Scope of utility model registration request] a bolt 2; a cylindrical plug 3 with a plurality of cuts 8 radially provided in the axial direction from only one end 7;
An anchor comprising an expanding tool 4 having a tapered surface 12 formed on the outer periphery, and screwing together the expanding tool 4 fitted from one end 7 of the plug 3 and a bolt 2 inserted from the other end 9. An annular groove 10 is provided on the outer periphery of the plug 3, and an O-ring 11 for preventing slipping is fitted in the annular groove so that an outer diameter is larger than the maximum diameter of the outer periphery of the plug 3. An anchor characterized by: