JP2004197561A - Spacer for anchor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spacer for an anchor easily mountable to the anchor such as a lock bolt from the side part and having excellent inserting property into an excavated hole. <P>SOLUTION: This spacer 1 for the anchor comprises four space holding pieces 12 and one cylindrical part and the other cylindrical part 13 provided on both sides respectively. One cylindrical part 11 is smaller than the outer diameter of the anchor to be applied, and the other cylindrical part 13 is placed in a loosely fitted state to the anchor when mounted because of being larger than the outer diameter of the anchor. A projection 11b provided at the inner surface of one cylindrical part 11 is engaged with a projection on the outer peripheral surface of the anchor for fixation, and when each space holding piece 12 is pressed to the inner surface of the excavated hole and deformed in a diameter reduced state when inserted, the other cylindrical part 13 is displaced to extend in a longitudinal direction. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to an anchor spacer used for mounting an anchor such as a rock bolt on the ground to maintain a space between the anchor and the inner wall surface of a drilling hole (an installation hole).

  Conventionally, anchors such as rock bolts have been widely used as a means for stabilizing the ground. These anchors are fixed to the ground by being filled with a suitable grout material around the anchors in a state where the anchors are inserted into installation holes formed in advance at the anchor installation locations. In this fixing operation, it is important to properly secure the covering thickness of the grout material, and for this purpose, various shapes of spacers (also called centerizers) for positioning the anchor at the center of the drilling hole, that is, at the hole center. Are widely used, and a plurality of the anchors are generally attached at predetermined intervals to the insertion portion of the anchor.

As a conventional example of such an anchor spacer, a substantially cylindrical insertion portion on both sides having a part of a peripheral wall cut off and a radially outwardly extending portion connected to the insertion holes on both sides are provided. Japanese Patent Application Laid-Open No. H11-163,086 discloses a plurality of strip-shaped support strips for maintaining intervals. This conventional anchor spacer is mounted at an appropriate position in the longitudinal direction of the anchor, so that a plurality of radially swelling strip-shaped support pieces abut against the inner wall surface of the drill hole, and the anchor is positioned at the center of the drill hole. In position. However, because the anchor spacer is formed from a single metal plate, when it is attached to the anchor, it is necessary to sequentially insert the spacer from one end of the insertion port to the other end of the insertion port. Is going. That is, although the insertion port portion is configured in a substantially cylindrical shape divided by a part of the peripheral wall, mounting from the side with respect to the anchor is not assumed at all, and no device is devised for that. Was.
Japanese Patent Publication No. Sho 64-537 (page 1, column 2, line 15 to page 2, column 4, line 12, FIG. 1 and FIG. 2)

  Further, in the spacer described in Patent Document 1 assuming insertion from the anchor end, the inner diameter of the insertion port portion is larger than the outer diameter of the anchor to be applied so that the spacer can be smoothly moved to a predetermined position in the longitudinal direction. It is set somewhat large. Therefore, for fixing to the anchor, after shifting the spacer from the end to the predetermined position, the inner diameter of the insertion port portion is reduced by squeezing the bulging portion of each support piece, etc. Needed to be tied.

  When the insertion ports on both sides are fixed as described above, each support piece is constrained at both ends by the insertion ports integrated with the support pieces, so that the spacer is made of a highly elastic material such as a spring steel plate. If it is formed, its elastic deformation capability will be greatly suppressed. For this reason, when each support piece passes through the elliptical portion of the hole, the elastic piece cannot be smoothly elastically deformed in accordance with the inner surface of the hole wall when the support piece passes through the elliptical portion of the hole, resulting in a large resistance. . Therefore, in this case, a decrease in insertability is inevitable. On the other hand, when the spacer is formed of a material lacking in elasticity, when applied to a drilling hole with poor straightness or circularity, the spacer that has been plastically deformed during insertion does not return to its original state, and the anchor is holed. There was a problem that it could not be located in the mind.

  By the way, in many grounds, gravel, earth and sand, bedrock, etc. are mixed and the ground is not uniform. For this reason, the rectilinearity of the excavation hole is often reduced, and a distorted portion is often formed over the entire length of the excavation hole without forming a true circular cross section. Under such circumstances, the spacer for supporting the spacing of the spacer, which does not cause a large resistance at the time of insertion into the drilling hole and which must maintain an appropriate distance between the anchor and the inner surface of the hole wall after the insertion. It has been desired that the steel has a deformability capable of following a certain degree in accordance with the state of the wall surface of the excavation hole, in addition to the above-mentioned improvement of the mountability.

  The present invention has been made in view of these problems of the related art, and an object of the present invention is to provide a spacer for an anchor in which the mountability of the spacer to the anchor is improved, and at the same time, the insertability to the excavation hole after mounting is improved. .

  In order to solve the above-mentioned problems, in the anchor spacer according to claim 1 of the present invention, both ends of the cylindrical portion having a part of the peripheral wall divided along the axial direction, and both ends of the cylindrical portion on both sides are divided. Are provided integrally, and each of the intermediate portions is provided with a plurality of spacing pieces which are bulged outward in the radial direction. The cylindrical portion is provided with locking means for substantially preventing displacement of the anchor in the longitudinal direction, and the other of the cylindrical portion is provided with a predetermined range in the longitudinal direction of the anchor. It is characterized in that it is in a loosely fitted state in which it can be displaced within.

  According to such a configuration, it becomes possible to open the divided cylindrical portions on both sides and mount the anchor from the side surface of the anchor, thereby increasing the efficiency of the mounting operation. Further, one (one end side) cylindrical portion of the anchor spacer is substantially displaced in the longitudinal direction by being locked to the outer peripheral surface of the anchor. On the other hand, since the other cylindrical portion (the other end side) is in a loosely fitted state with respect to the anchor, each of the spacing holding pieces integral with the cylindrical portions on both sides thereof has its bulging portion. Is pressed from the outside and contracted in the radial direction, the cylindrical portion on the other end is displaced in the longitudinal direction of the anchor with this diameter reducing operation. That is, when any of the plurality of spacing pieces is pressed radially inward (anchor side) by contacting a rock or the like protruding from the inner surface of the borehole, individual rigidity based on the overall cylindrical shape causes individual Deformation of the spacing member is suppressed, and all the spacing members are linked to each other and behave in such a manner that the other end extends in the longitudinal direction of the anchor, starting from the cylindrical portion on one end. Therefore, in the anchor equipped with this spacer, when inserted into the drilling hole, each of the spacing members can be deformed (flattened) to some extent following the unevenness of the inner surface of the drilling hole, thereby improving the insertability. Also leads to.

  Furthermore, in the invention according to claim 2, since a protrusion that can be locked to a ridge formed on the outer peripheral surface of the anchor, such as a deformed reinforcing bar or a lock bolt made of a full thread bolt, is employed as the locking means, The locking state between the anchor and the spacer is enhanced, and the displacement of the entire spacer in the longitudinal direction at the time of insertion into the excavation hole can be reliably prevented.

With the anchor spacer according to the present invention, the following effects can be obtained.
(1) Since the anchor can be attached to the anchor from the side, the attachment operation is extremely simple, and the workability is greatly improved. In addition, since it is mounted on the anchor via the tubular portions on both sides, a very stable mounting state can be obtained.
(2) The cylindrical portion on one end is positioned on the anchor, but the cylindrical portion on the other end is in a loosely fitted state with respect to the anchor, and the bulging portions of the spacing members are radially inward. As the diameter is reduced, the anchor moves so as to extend in the longitudinal direction of the anchor, so that the insertability of the anchor into the borehole is improved.
(3) The anchor spacer according to claim 2 can be easily set to a state in which the anchor is prevented from being displaced in the longitudinal direction while being attached to the anchor from the side.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. 1 to 4 show a specific example of an anchor spacer according to the present invention, and are a front view, a left side view, a bottom view, and a right side view, respectively. The illustrated anchor spacer 1 is made of a steel plate having an appropriate elasticity, and has one cylindrical portion 11 formed in a substantially cylindrical shape, and four spacers 12 provided at one end in the axial direction thereof. And the other cylindrical portion 13 arranged on the other end side of the space holding piece 12.

  As shown in FIGS. 2 and 3, one of the cylindrical portions 11 has a part of the peripheral wall divided in the axial direction, opens at a predetermined width, and has both ends 11 a of the peripheral wall forming the opening 14. , 11a are folded back to the outer peripheral surface side. Further, a projection 11b is provided on the inner surface of the peripheral wall at a position opposing the opening 14 with respect to the axis. The projection 11b is displaced in the longitudinal direction (position) by engaging with the ridge at an appropriate position as a locking means for an anchor having a ridge (knot) formed on the outer peripheral surface such as a deformed steel bar. Deviation) is prevented. The locking means is not limited to the projection 11b, and its shape, number, position, and the like can be changed as appropriate. Further, as is clear from FIG. 2, the cylindrical portion 11 in the present embodiment is not formed so that the entire peripheral wall has the same curvature, but the arc portion on the protrusion 11b side is formed with a larger curvature than the arc on both side portions thereof. It is close. Although this is common to the other cylindrical portion described later, it is based on the cross-sectional shape of the anchor (lock bolt) to be applied. Depending on the cross-sectional shape of the anchor, this is not necessarily required. It is not limited to the shape.

  As shown in FIG. 4 and the like, a part of the peripheral wall of the other cylindrical portion 13 is divided along the axial direction like the one cylindrical portion 11 and is opened, and an opening 15 is formed. The opposite side ends 13a, 13a are folded back to the outer peripheral surface side. However, the inner diameter is set to be larger than the outer diameter of the lock bolt to be applied, and is different from the one cylindrical portion 11 in that it is in a loose fit state when mounted. This is so that when the four spacers 12 to be described later are deformed to reduce the diameter during insertion into the excavation hole, the other cylindrical portion 13 can be smoothly displaced in the longitudinal direction on the lock bolt. It is. Note that the interval between the openings 15 is set smaller than the minimum transverse width of the lock bolt, including the opening 14 of one of the tubular portions 11, so that the opening does not easily come out of these openings 14 and 15. I have. As is clear from FIG. 3 and the like, the positions of the openings 14 and 15 in the circumferential direction are substantially in a line along the axial direction of the spacer 1.

  Next, the four interval holding pieces 12 are located between the cylindrical portion 11 and the cylindrical portion 13 and bulged in an arc shape such that the central portion has the maximum diameter, as is apparent from FIGS. , At intervals of approximately 90 degrees in the circumferential direction. In this case, the interval between the central portions, which are the maximum diameter portions (top portions) of the interval holding pieces at the opposing positions, is set to be somewhat larger than the inner diameter of the excavation hole. The interval between the tops may be equal to or smaller than the inner diameter of the drill hole. In short, it is only necessary to hold the anchor near the center of the excavation hole and to secure a necessary covering thickness.

  Next, a method for using the anchor spacer 1 will be described. FIG. 5 shows a state where the lock bolt R (anchor) to which the anchor spacer 1 is attached is installed in the excavation hole H. The lock bolt R used here is formed of a threaded-shaped deformed steel bar, and two flat portions are formed on the outer peripheral surface thereof along the longitudinal direction at opposing positions sandwiching the axis. It has a shape divided by the part. At the time of mounting, at a predetermined position of the lock bolt R, the opening 14 of the one tubular portion 11 and the opening 15 of the other tubular portion 13 are addressed toward the row of screw joints, and strongly pressed from behind. As a result, both side end portions 11a, 11a and both side end portions 13a, 13a open beyond the width between the flat portions of the lock bolt R while resisting the elasticity of the material. Crosses over the flat portion, and the lock bolt R is fitted into one of the tubular portions 11 and the other tubular portion 13. At this time, the protrusion 11b on the inner surface of the one cylindrical portion 11 is fitted into the groove between the screw nodes, and the lock bolt R is substantially prevented from being displaced in the longitudinal direction. In the relationship between the width of the groove between the threaded joints and the size of the protrusion 11b, there may be some displacement within the range of the width of the groove. In this case, one cylindrical portion 11 resiliently grips the lock bolt R from the outer peripheral surface side, but the other cylindrical portion 13 has an inner diameter larger than the outer diameter of the lock bolt R. Therefore, they are not grasped, and the relationship between them is a loose fit state. Thereby, the other cylindrical portion 13 can be displaced in the longitudinal direction of the lock bolt R within a predetermined range. However, since the width of the opening 15 is smaller than the width between the flat portions of the lock bolt R, the other cylindrical portion 13 does not easily come off the lock bolt R.

  In this manner, the anchor spacer 1 according to the present invention can be mounted on the lock bolt R by one-touch operation from the side. In addition, in order to increase the gripping force of the one cylindrical portion 11 to more reliably prevent the detachment, it is effective to use an appropriate auxiliary member. For example, in each of the cylindrical portions 11 and 13, the opening is stopped by a U-shaped clip straddling the both sides 11a and 11a and the back side of the folded portion of the both ends 13a and 13a, or one of the cylindrical portions In the portion 11, a binding wire may be wound around the boundary between the both end portions 11 a, 11 a and the spacing member 12. Further, the tubular portion may have a split structure that can be opened and closed, and the tubular portion itself may be provided with a means for maintaining a closed state.

  Here, in each of the interval holding pieces 12 curved outward in an arc shape, the distance from the axis of the anchor spacer 1 to the central top serving as the maximum diameter portion is set to be slightly larger than the radius of the excavation hole H. ing. The spacer 1 is mounted such that one of the cylindrical portions 11 is located at the tip of the lock bolt R. Then, with the insertion of the lock bolt R into the drill hole H, first, each spacing holding piece 12 of the spacer 1 comes into contact with the entrance of the drill hole H, and the pressing force applied to the lock bolt R causes the front inclined surface. When pressed, it is deformed to fall to the lock bolt R side (axial side). That is, the central top portion receives a force in the direction of reducing the diameter. Further, since the cylindrical portion 13 is surrounded with an appropriate gap left from the lock bolt R, the other cylindrical portion 13 interlocks with the expansion and contraction deformation of each spacing holding piece 12 generated during insertion. The side has a structure which can advance and retreat in the longitudinal direction. Therefore, the lock bolt R to which the spacer 1 is attached is smoothly inserted into the excavation hole H by appropriately elastically expanding and contracting the spacing pieces 12 according to the unevenness of the inner surface of the excavation hole H. Can be installed in any location.

  FIGS. 6 and 7 are explanatory views showing the behavior of the expansion and contraction deformation of each of the spacing members 12. In the spacer 1 according to the present invention, by adopting an integral structure in which each of the space holding pieces 12 is connected to the substantially cylindrical tubular portions 11 and 13 at both ends thereof, individual free elastic deformation is restrained to a considerable extent. I have. For this reason, when any one of the spacing members 12 receives a pressing force inward (in the diameter reducing direction), the other cylindrical portion 13 is changed as the spacing member 12 changes from a curved state to a flat state. Push backward (in the direction opposite to the insertion direction). At this time, since the other interval holding pieces 12 are connected to the other cylindrical portion 13 in the same manner, they also have a structure in which they are also reduced in diameter in conjunction with each other. That is, in the spacer 1 of the present invention, when a radial force from the outside toward the axis is applied to at least one of the spacing pieces 12, the radius at the central top corresponding to the maximum diameter portion is increased. Decreases by L1, and at the same time, the entire length of the spacer 1 increases by L2. By exhibiting such behavior, the insertability of the anchor is improved, and at the same time, the anchor can be installed at a position close to the axis of the excavation hole H.

  8 and 9 show another embodiment of the anchor spacer according to the present invention, which is a front view and a left side view, respectively. The illustrated anchor spacer 2 is formed of the same material as that of the above-described embodiment, and has the same basic configuration. However, one of the cylindrical portions 21 is substantially divided into two portions in the axial direction. different. That is, one cylindrical portion 21 is composed of a grip portion 21a having an inner diameter smaller than the outer diameter of the anchor to be applied and a loose fitting portion 21b having an inner diameter larger than the outer diameter of the anchor to be applied. Has a notch 21c. The notch 21c occupies most of the circumference, and the grip portion 21a and the loose fitting portion 21b are connected to each other at a part of the circumference. The four spacing pieces 22 are connected at one end thereof to the loose fitting portion 21b and at the other end thereof to the other cylindrical portion 23, respectively. The other cylindrical portion 23 is set to have such a size as to be loosely fitted to the anchor in the mounted state, similarly to the loose fitting portion 21b of the one cylindrical portion 21.

  As is clear from FIG. 9, each of the one cylindrical portion 21 and the other cylindrical portion 23 composed of two cylindrical portions has a part of the peripheral wall divided along the axial direction and has a predetermined width. It is open at. The width of the opening is set smaller than the outer diameter of the anchor to be applied, and the positions on the circumference are aligned in the axial direction of the spacer. In addition, two protrusions 21d are provided on the inner surface of the grip portion 21a of the one cylindrical portion 21 at opposing positions, and both end portions 21e, 21e forming the opening 24 are folded back to the outer peripheral surface side. I have. Since the spacer 2 has a configuration in which each spacing piece 22 is substantially separated from the grip portion 21a, even if the grip portion 21a expands and contracts according to the size of the anchor diameter, the cross-sectional shape, and the like. The effect hardly reaches the spacing member 22. For this reason, the desired uniform arrangement of the spacing pieces 22 is maintained, which is convenient for securely holding the anchor at the center of the hole. Also in this case, the anchor can be easily attached to the anchor from the side, and the operability is not much different. Is the same as

  In each of the above-described embodiments, an example in which a spring steel material is used as a material for the reason that the applicable range of the drilling diameter is expanded has been described. However, a normal steel material or a synthetic resin can be used. In addition, the number of the spacing members is not limited to four, but may be three or five or more. It is, of course, possible to implement the change.

It is a front view which shows an example of the spacer for anchors by this invention. It is a left view of the said anchor spacer. It is a bottom view of the said anchor spacer. It is a right view of the said anchor spacer. It is a reference drawing showing the use condition of the above-mentioned anchor spacer. It is explanatory drawing which shows the expansion-contraction behavior of the spacing member in the said anchor spacer. FIG. 7 is a left side view of FIG. 6. It is a front view which shows the other example of the spacer for anchors by this invention. It is a left view of the said anchor spacer.

Explanation of reference numerals

1, 2,... Anchor spacers, 11, 13, 21, 23,... Tubular part, 12, 22,... Spacing holding pieces, 11a, 13a, 21e. , 15, 24 ... opening, H ... drilling hole, R ... lock bolt

Claims (2)

  A cylindrical part on both sides where a part of the peripheral wall is divided along the axial direction, and both ends are integrally connected to the cylindrical parts on both sides, and the respective intermediate parts bulge outward in the radial direction. A plurality of spaced-apart holding pieces, an anchor spacer that can be attached to an anchor, such as a lock bolt, from the side by opening a divided portion of the tubular portion, and an anchor is provided on one of the tubular portions. A locking means for substantially preventing displacement in the longitudinal direction of the anchor is provided, and the other of the cylindrical portions is in a loosely fitted state in which the tubular portion can be displaced within a predetermined range in the longitudinal direction of the anchor. Spacer.   2. The anchor spacer according to claim 1, wherein the locking means is a protrusion that can be locked on a ridge formed on an outer peripheral surface of the anchor. 3.

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