JP2006312879A - Underground anchor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an underground anchor which can be buried even in the hard ground by rotatively excavating the ground and entering into the ground by the use of a small-sized rotary machine. <P>SOLUTION: This underground anchor, the spiral excavating blade of which is provided on the leading-end side of a supporting rod, is buried in the ground while rotatably penetrating the ground. In the underground anchor, the spiral excavating blades are intermittently provided in the axial direction of the supporting rod; a rotatively-entry-direction leading end of each spiral excavating blade is acutely formed; the diameter of the spiral excavating blade is made gradually larger in the back end direction of the supporting rod from the leading end of the supporting rod; and the pitch of a spiral of each spiral excavating blade is made gradually larger in the back end direction of the supporting rod from the leading end of the supporting rod. In addition, desirably, the rotatively-entry-direction leading end and the outer peripheral edge of each spiral excavating blade are acutely formed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an underground anchor that supports a branch line of a utility pole or a building structure in the ground.

  Conventionally, this type of underground anchor is configured such that, for example, as shown in Patent Document 1, a spiral excavating blade is intermittently provided on the tip side of a support rod embedded in the ground.

Since this underground anchor has a spiral excavating blade, if it is rotated in a predetermined direction while being pressed using a rotary machine (rotary machine), a force propelled into the ground by the spiral excavating blade is generated and gradually Enter the ground. As a result, underground anchors are buried.
JP-A-8-284160

  However, the conventional underground anchor has the following drawbacks due to the shape of the spiral excavation blade. That is, first, since the rotational resistance of the spiral excavation blade when rotating and entering the ground is large, a large rotating machine is required. Second, when the ground is hard, the excavation performance of the spiral excavation blade is low, so that the underground anchor is difficult to rotate. Thirdly, since the spiral excavation blade is provided on the support rod by welding, the manufacturing cost is increased.

  The present invention has been made to solve the above-mentioned drawbacks, and an object of the present invention is to provide an underground anchor that can be embedded by rotating excavation approach even on hard ground using a small rotating machine. There is.

  In order to achieve the above object, the present invention has a spiral excavation blade on the tip side of a support rod, and the underground excavation blade embedded in the underground by rotating and entering the ground, the spiral excavation blade is attached to the support rod. It is provided intermittently in the axial direction, and the tip of the rotational approach direction of each spiral digging blade is sharply formed, and the diameter of the spiral digging blade is gradually increased from the tip of the support rod to the rear end direction. The spiral pitch of the spiral excavation blade is gradually increased from the front end of the support rod toward the rear end.

  Further, the tip and outer peripheral edge of each spiral excavation blade in the rotational approach direction are sharply formed.

  According to the first aspect of the present invention, in the underground anchor that has the spiral excavation blade on the tip side of the support rod and is embedded by rotating and entering into the ground, (a) the spiral excavation blade is axially disposed on the support rod. (B) the tip of each spiral digging blade is sharply formed in the rotational approach direction, and (c) the diameter of the spiral digging blade is gradually increased from the tip of the support rod toward the rear end. And (d) a combination of the four requirements of gradually increasing the pitch of the spiral of each spiral digging blade from the front end of the support rod toward the rear end, with respect to the ground of each excavation blade during rotation of the support rod Since the cutting resistance is remarkably reduced, it is possible to reduce the rotational force required to rotate the underground anchor. Accordingly, it is possible to use a hydraulic rotating machine attached to a relatively small civil machine such as a backhoe.

  According to the invention of claim 2, since each spiral excavation blade is formed not only at the front end in the rotation approach direction but also at the outer peripheral edge, the cutting resistance to the ground of the excavation blade during rotation of the support rod is further reduced. Therefore, underground anchor burial work can be performed more smoothly.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of a state in which an underground anchor a according to an embodiment of the present invention is embedded in the underground G.

  The support rod 1 is formed in a desired length by connecting support rods 1a and 1b made of two rods having a predetermined length. That is, as shown in an enlarged view in FIG. 2, a screw hole 3 is provided in the axial center of the head 2 formed in the hexagonal column shape of the lower support rod 1a, and the upper support is provided in the screw hole 3. One support rod 1 is configured by screwing a screw rod (not shown) provided at the lower portion of the rod 1b.

  A hexagonal columnar head 2 having a screw hole 3 is also provided on the upper portion of the upper support rod 1b in the same manner as the upper portion of the lower support rod 1a. Then, after the underground anchor “a” is buried in the screw hole 3 of the head 2 of the support rod 1 b as shown in FIG. 1, an eyebolt 4 is screwed, and the electric pole of the utility pole is passed through the eyebolt 4. It is comprised so that a branch line etc. can be attached.

  The through holes 5 and 5 provided in the heads 2 and 2 of the support rods 1a and 1b respectively penetrate in the direction orthogonal to the axial direction of the heads 2 and 2, and the heads 2 and 2 will be described later. When inserted into a rotating machine M (see FIG. 2) and coupled, a pin (not shown) is inserted to maintain the coupled state.

  The support bar 1b shown in FIG. 1 is an added auxiliary support bar, and the support bar 1 is configured by connecting two support bars 1a and 1b in the example of FIG. When the burial depth is further required due to the soil quality of the underground G, that is, the nature of the ground, another support rod (1b) is further connected. Further, when one support bar (1a) is sufficient due to the soil quality of the ground, the upper support bar 1b can be omitted.

  In addition, although it is also possible to comprise one support rod 1 without making it a connection type as mentioned above, when making it a connection type as mentioned above, the length can be adjusted by the property of the ground, When the length is relatively short, there are advantages such as easy production by casting and easy transportation.

  In the figure, reference numerals 10a, 10b, and 10c denote spiral excavating blades (hereinafter referred to as "excavating blades") that are provided intermittently with a predetermined interval on the tip side of the lower support rod 1a (lower side in FIGS. 1 and 2). "). Further, 20 is a drill portion, and 30 is a constricted portion. Reference numeral 40 denotes a collar provided near the rear end of the support bar 1a. Hereinafter, these will be described with reference to FIGS.

  The outer diameters of the excavating blades 10a, 10b, and 10c are the smallest outer diameter of the excavating blade 10a on the front end side, and are gradually increased toward the rear end portion. The pitch of 10a is the smallest, and is gradually increased toward the rear end. Each of the excavating blades 10a, 10b, and 10c is the same except for their diameter and pitch. Therefore, when the excavating blade 10c is described as an example, the helical length of the excavating blade 10c is approximately 540 degrees (1.5 rotations). ) Rotation angle. Therefore, when the support bar 1a is rotated once in the ground G in a predetermined direction, that is, in the direction in which the tip of the digging blade advances (rightward in the illustrated example), the axial center is equal to the helical pitch of the digging blade 10c. It is possible to advance (approach) in the direction.

  The tip of the excavation blade 10c in the direction of entering the underground G (hereinafter, “underground” is sometimes referred to as “ground”), that is, the portion indicated by the symbol A in FIG. The outer peripheral edge of the excavating blade 10c, that is, the portion indicated by the symbol B in FIG. 2 is also sharply formed as shown in FIG. Further, the rear end side of the excavating blade 10c, that is, the portion indicated by reference numeral C in FIG. 2 is formed in a state in which the pitch of the spiral is formed larger than the other portions and is raised.

  The drill portion 20 is provided at the tip of the support bar 1a and has a shape of a tip of a well-known drill used in machining. That is, the tip of the support bar 1a is formed in a substantially cone shape. And the cutting blades 21a and 21b are provided on the opposite side with respect to the axial center of the support bar 1a in the form which protrudes from the outer periphery at the front-end | tip. As shown in FIG. 4, the portions of the cutting blades 21a, 21b opposite to the drill rotation direction during drilling (see the arrow in FIG. 4) are indicated by chain lines in order to enhance the cutting effect in the same manner as known drills. A relief is provided.

  The constricted part 30 is provided in the immediate upper side of the drill part 20, and is formed by forming the support bar 1a to have a smaller diameter than other parts. The constricted portion 30 forms a space in which so-called cutting powder generated by the drill portion 20 can be stored, and has a role of helping the drill portion 20 enter the ground.

  The collar part 40 is provided in the lower part of the head part 2, and is formed in a larger diameter than the support rod 1a. As shown in FIG. 1, the collar portion 40 is pushed up by the rotation of the excavating blades 10a, 10b, and 10c when the support rod 1 is used as a combined body of the lower support rod 1a and the upper support rod 1b. It is possible to effectively suppress the earth excavated. And the excavation blades 10a, 10b, 10c are provided intermittently, the tip and the outer periphery are formed sharply, the outer diameter is gradually increased from the lower side to the upper side, When the support bar 1a is rotated, the excavating blades enter while cutting the ground easily with a small resistance, so that the amount of soil to be pushed up is suppressed. In addition, since it is pressed by the flange portion 4 provided on the upper portion of the support bar 1a, the effect of the so-called non-exhaust earth method can be further enhanced. In addition, by forming the head portion 2 with a large diameter, the head portion can also serve as the collar portion 40.

  The support rod 1a, the head 2, the flange 40, the excavating blades 10a, 10b, and 10c, the constricted part 30, and the drill part 20 are integrally formed by casting. In addition, in the casting, by using a mold that can be divided along the axis of the support bar 1a, it can be manufactured very easily without the need for a core.

  This underground anchor a is casted with spheroidal graphite cast iron, and after quenching at 900-930 ° C. × 1.0-1.5 Hr at a constant temperature, a salt at 370-380 ° C. × 1.0-1.5 Hr at a constant temperature. Upper bainite treatment (tempering treatment for obtaining an upper bainite structure) by a bath (heat bath) is performed. Therefore, this underground anchor a can have an excellent excavation function even if the ground G is hard because the hardness is high.

  The screw hole 3 and the through hole 5 of the head 2 are made by machining after casting.

  As described above, since the underground anchor a has a low resistance when the support rod 1a is rotated into the ground due to the shape of the excavating blades 10a, 10b, and 10c, the underground anchor a is embedded in the underground G. Can use a rotating machine M that rotates hydraulically attached to a relatively small civil machine such as a backhoe.

  Since the rotary machine M is provided with an insertion port (not shown) corresponding to the hexagonal column of the head 2, after inserting the head 2 of the support bar 1 a into the insertion port, the pin is inserted into the through hole 5. (Not shown) is inserted and the support bar 1a is held by the rotary machine M.

  When the rotating machine M is rotated, the drill unit 20 enters the ground G in a form that cuts the ground G, that is, in a form that the drill makes a hole. Next, the excavation blades 10a, 10b, and 10c enter the ground G in a form guided by holes drilled by the drill unit 20. Moreover, the excavating blades 10a, 10b, and 10c are provided intermittently, the outer diameter is smaller toward the lower side, the tip and the outer periphery are sharpened, and the rear ends of the excavating blades 10a, 10b, and 10c Since the side is bounced up, the resistance to biting into the ground G can be reduced, and therefore the burial can be carried out with a smaller rotational force than in the prior art. Moreover, by having the collar part 40 in the lower part of the head 2, it is possible to embed it by a non-earth-free construction method without performing earth evacuation to the outside of the underground G due to the underground anchor a being buried. . In addition, the soil volume can be reduced and a compact soil wall can be obtained. For this reason, a desired support force can be obtained without generating a space around the support rod 1a.

  When the head 2 of the support bar 1a is buried close to the ground surface, the upper support bar 1b is screwed into the screw hole 3 of the head 2 and connected. After the connection, the upper support bar 1b is connected. The head 2 is set on the rotary machine M, and the underground anchor a is continuously buried.

  When the head 2 of the upper support rod 1b is buried close to the ground surface (see FIG. 1), the rotating machine M is removed, and the eyebolt 4 is screwed into the screw hole 3 of the head 2 to enter the ground. The anchor a is buried.

It is a perspective view of the state where the underground anchor concerning one embodiment of the present invention was buried. It is an expansion perspective view of a lower support bar. It is an AA line expanded sectional view of FIG. It is the enlarged view which looked at the drill part from the bottom.

Explanation of symbols

a Underground anchor 1, 1a, 1b Support rod 10a, 10b, 10c Spiral excavation blade (excavation blade)
20 drill part 40 brim part G underground (ground)

Claims (2)

  In the underground anchor that has a helical excavation blade on the tip side of the support rod and is rotated and entered into the ground, the spiral excavation blade is provided intermittently in the axial direction of the support rod, and Each spiral digging blade has a sharp tip in the rotation approach direction, the diameter of the spiral digging blade is gradually increased from the tip of the support rod toward the rear end, and the spiral pitch of each spiral digging blade is An underground anchor that is gradually enlarged from the front end to the rear end of the support bar.   2. The underground anchor according to claim 1, wherein each of the spiral excavating blades is formed with a sharp tip in the rotational approach direction and an outer peripheral edge.

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