JP4248622B2 - Underground anchor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an underground anchor that supports a branch line of a utility pole or a building structure in the ground.
[0002]
[Prior art]
Conventionally, this type of underground anchor is configured, for example, as shown in JP-A-8-284160, in which a spiral excavation blade is intermittently provided on the tip side of a support rod embedded in the ground. ing.
[0003]
When the underground anchor having this spiral excavating blade is rotated in a predetermined direction while being pressed by a rotary machine (rotary machine), a force that the spiral excavating blade bites into the ground and propels it is generated gradually. enter in. As a result, underground anchors are buried.
[0004]
[Problems to be solved by the invention]
However, the underground anchor having the above-described conventional helical excavation blade requires a large rotating machine to rotate and enter the underground anchor, and when the ground is hard, the underground anchor is difficult to enter. There were drawbacks. Further, since the spiral excavation blade is provided by welding to the support rod, there is a drawback that the manufacturing cost increases.
[0005]
The present invention has been made to solve the above-described drawbacks, and the object thereof is to make it possible to easily rotate even a hard ground using a small rotating machine, and to manufacture at low cost. It is to provide an underground anchor that can be used.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a ground anchor having a spiral excavation blade on the tip side of a support bar and entering and buried in the ground by being pressed and rotated. (A) A drill portion is provided at the tip of the support rod, the spiral excavation blade is provided above the drill portion, and the support rod, the spiral excavation blade, and the drill portion are integrally cast, (b) The spiral excavation blade is intermittently provided in the longitudinal direction of the support rod, and the diameter of the spiral excavation blade is increased as it moves away from the front end of the support rod in the rear end direction, And the front-end | tip and outer periphery of the approach direction of each said spiral excavation blade are formed sharply, (c) The said drill part is formed in cone shape, and it is substantially linear from the front-end | tip part of the cone to a base end part. (D) in front of the support rod Serial some unusual information which must be specially constricted portion is provided in the immediate vicinity above the drill section, it is characterized in that is provided on the most distal end of the distal end of the helical drilling blade the neck portion of the (e) the support rod.
In the preferred embodiment of the present invention, the ground anchor support rod, spiral digging edge and drill part is cast in spheroidal graphite cast iron is characterized in that it is upper bainite processing.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
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.
[0008]
Generally speaking, the underground anchor a includes a support rod 1, spiral excavation blades 10 a, 10 b, 10 c provided intermittently on the outer periphery in the vicinity of the tip of the support rod 1, and the tip of the support rod 1. And a constricted portion 30 formed close to the upper side of the drill portion 20 of the support rod.
[0009]
The support bar 1 is formed in a desired length by connecting support bars 1a and 1b made of two bar members having a predetermined length. That is, a screw hole 3 is provided in the axial center of the head 2 formed of a hexagonal column of the support rod 1a positioned below, as shown in FIG. 2 in which the support rod 1a is enlarged. A screw rod (not shown) provided below the upper support rod 1b is screwed into the screw hole 3 to constitute one support rod 1.
[0010]
Similarly to the upper part of the lower support bar 1a, the upper part of the upper support bar 1b is also provided with a head 2 made of a hexagonal column having a screw hole 3. 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.
[0011]
The through holes 5 and 5 provided in the heads 2 and 2 of the support rods 1a and 1b are provided in a direction orthogonal to the axial direction of the heads 2 and 2, respectively. When the head 2 is inserted and set in (see FIG. 2), it is used for insertion of a pin (not shown) that holds that state.
[0012]
The support bar 1b shown in FIG. 1 is an added auxiliary support bar. In the example of FIG. 1, the support bar 1 is composed of two support bars 1a and 1b. When the burial depth is further required due to the soil quality, that is, the properties 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.
[0013]
The support rod 1 can be configured as a single piece without being connected as described above. However, as described above, the length can be adjusted depending on the properties of the ground, and the length is relatively short. Advantages such as easy production by casting and easy transportation.
[0014]
In the figure, reference numerals 10a, 10b, and 10c denote spiral excavating blades (hereinafter referred to as intermittent cutting blades) that are provided at predetermined intervals on the distal end side (lower side in FIGS. 1 and 2) of the lower support rod 1a. , Called "excavation blade"). Further, 20 is a drill unit, the further, 30 is constricted portion. And 40 is a collar part. Hereinafter, these will be described with reference to FIGS.
[0015]
Excavation blades 10a, 10b, and 10c are formed such that the outer diameter increases toward the rear end side (upper side in FIGS. 1 and 2) of the support bar 1a, that is, the distance from the drill portion 20, and the helical pitch increases. It is formed to become. Each digging edge 10a, 10b, 10c, since the non-difference in the outer diameter and pitch are identical, describing the digging edge 10c located above example, the spiral of the digging edge 10c is a support rod 1a 1 It has a length of 5 rotations. Therefore, when the support bar 1a is rotated once in one direction (right direction in the illustrated example) in the ground G, it can advance (enter) in the axial direction by the spiral pitch of the excavating blade 10c.
[0016]
The tip that enters the underground G of the excavating blade 10c (hereinafter, “underground” is sometimes referred to as “ground”), that is, the portion indicated by the symbol A in FIG. 2 is sharply formed, 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 the symbol C in FIG. 2 is formed in a state in which the pitch of the spiral is larger than the other portions, and is in a state of jumping up.
[0017]
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 drill part 20 is formed in a substantially cone shape. And the cutting blades 21a and 21b which protrude substantially linearly from the front-end | tip part of the cone to the base end part are provided in the mutually opposite side with respect to the axial center of the support bar 1a. As shown in FIG. 4, the portion opposite to the drill rotation direction (see the arrow in FIG. 4) at the time of excavation of the cutting blades 21 a and 21 b is a chain line in order to enhance the cutting effect in the same manner as a known drill. A relief is provided as shown. Further, by providing the cutting blades 21a and 21b, a concave portion 21c is formed as a natural shape on the front side in the drill rotation direction of each cutting blade during excavation.
When a drill having a spiral blade is cut into a hard ground, the tip may be bent or damaged due to insufficient strength. However, the drill portion 20 of the underground anchor according to the present invention has a cone shape and has substantially straight cutting blades 21a and 21b from the distal end portion to the proximal end portion of the cone. Is so large that it can be easily cut and crushed even on hard ground such as rock.
[0018]
The constricted portion 30 is provided immediately above the drill portion 20, and is configured by forming the support rod 1a to have a smaller diameter than other portions. And since it is provided in the immediate upper part of the drill part 20 in which the cutting blades 21a and 21b are formed, at the time of excavation, what is called grinding powder generated by the cutting blades 21a and 21b by the rotation of the drill part 20 Is moved from the recessed portion 21c through the recessed portion to the constricted portion 30 and accommodated. The entry side tip of the most excavation blade 10 a is provided in the constricted portion 30. Therefore, when the cutting powder generated by the cutting blades 21a and 21b passes through the recess 21c and is stored in the constricted portion 30, the cutting powder is immediately discharged upward by the drilling blade 10a. The ground cutting efficiency is improved, and entry into the ground is much easier than when the constricted portion 30 is not provided.
[0019]
The collar part 40 is provided in the lower part of the head 2, and is formed with a larger diameter than the support rod 1a. The collar portion 40 can suppress the soil that is about to be discharged by the rotation of the excavating blades 10a, 10b, and 10c, and can further enhance the effect of the so-called no-draining method. The collar portion 40 can be omitted by forming the head portion 2 with a large diameter.
[0020]
Above the support rod 1a, a head 2, digging edge 10a, 10b, 10c, the drill part 20, the constricted portion 30, and the flange portion 40 is an integral structure 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.
[0021]
Underground anchor a is casted with spheroidal graphite cast iron, and after quenching at 900-930 ° C. × 1.0-1.5 Hr at constant temperature, salt bath at 370-380 ° C. × 1.0-1.5 Hr at constant temperature Upper bainite treatment (heat bath) (tempering treatment for obtaining an upper bainite structure) is performed. Therefore, since this underground anchor a has a very high overall hardness and toughness including the drill portion 20 in particular, it has an excellent excavating function even for the hard ground G.
[0022]
The screw hole 3 and the through hole 5 of the head 2 are made by machining after casting.
[0023]
In order to embed the underground anchor a having the above structure in the underground G, a rotating machine M capable of obtaining a rotational force by hydraulic pressure is attached to a relatively small civil engineering machine such as a backhoe.
[0024]
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.
[0025]
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 10 a, 10 b, and 10 c enter the ground G in a form that is guided by holes drilled by the drill unit 20. Moreover, the excavating blades 10a, 10b, 10c are provided intermittently, the outer diameter of the tip is smaller, and the tip and outer periphery are formed sharper, so the resistance to biting into the ground G is less, Therefore, embedding can be performed with a smaller rotational force than in the past. Further, the excavating blades 10a, 10b, and 10c are provided intermittently, the spiral pitch of the excavating blades 10a, 10b, and 10c is gradually increased toward the rear end side, and the collar portion 40 is provided. Therefore, it is possible to embed by the non-exhaust earth method without performing the earth removal outside the underground G due to the burying of the underground anchor a. 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.
[0026]
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 rotating machine M, and the underground approach of the underground anchor a is continued.
[0027]
When the head 2 of the upper support bar 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 so that it is underground. The anchor a is buried.
[0028]
【The invention's effect】
According to the present invention, firstly , since the support bar, the spiral excavation blade, and the drill portion are integrally cast , the underground anchor is generally very strong. Secondly , a plurality of spiral excavation blades are provided intermittently in the longitudinal direction of the support rod, and the diameter of the spiral excavation blade is increased as the distance from the front end of the support rod to the rear end direction increases. In addition, since the front end and the outer peripheral edge in the approach direction of each spiral excavation blade are sharply formed , the resistance received during ground excavation is reduced, so that the required excavation force is reduced. Thirdly, since the drill part at the tip of the support rod has a cone shape and has a substantially straight cutting blade from the tip part to the base end part of the cone, the strength and durability are very large. This can be easily cut and crushed even on hard ground. Fourth, a recess is formed on the front side of the cutting rod of the drill portion in the support rod rotation direction, and a constricted portion is provided immediately above the drill portion, and the tip of the spiral excavation blade on the most distal end side of the support rod. Since it is provided in the constricted part, when the cutting powder generated by the cutting blade is accommodated in the constricted part through the recessed part , the cutting powder is immediately discharged upward from the constricted part by the excavating blade, The ground cutting efficiency of the drill portion is improved, and drilling into the ground becomes much easier.
Therefore, according to the present invention, the underground anchor is generally very tough, the drill part has very high strength and durability, and the dust generated by excavation is housed in the constriction part, and Immediately after being discharged from the constricted portion by the most spiral drilling blade, the ground cutting efficiency of the drill portion is improved, the diameter of the plurality of spiral drilling blades gradually increases in the rear end direction of the support rod, and each The combination of the fact that the tip and outer peripheral edges of the spiral excavation blade are sharply formed and the required excavation force may be small is combined, and it is possible to easily rotate and enter even the hard ground using a small rotating machine. A special effect that cannot be obtained with conventional underground anchors.
[0029]
According to the invention of claim 2, the ground anchor of the above structures are cast in spheroidal graphite cast iron, since it is upper bainite processing, very high overall hardness and toughness, including a drill portion in Japanese Therefore, it exhibits an excellent drilling function even for hard ground. Therefore, even if it is hard ground, it can be easily rotated and embedded without worrying about the strength of the underground anchor.
[Brief description of the drawings]
FIG. 1 is a perspective view of a state where an underground anchor according to an embodiment of the present invention is embedded.
FIG. 2 is an enlarged perspective view of a lower support bar.
FIG. 3 is an enlarged cross-sectional view taken along line AA in FIG.
FIG. 4 is an enlarged view of a drill portion viewed from below.
[Explanation of symbols]
a Underground anchor 1, 1a, 1b Support rod 2 Head 3 Screw hole 4 Eye bolt 5 Through hole 10a, 10b, 10c Spiral excavation blade (excavation blade)
20 Drill part 21a, 21b Cutting blade 21c Recessed part 30 Constricted part 40 Collar 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 enters the underground by being pressed and rotated,
(A) A drill portion is provided at the tip of the support rod, the spiral excavation blade is provided above the drill portion, and the support rod, the spiral excavation blade, and the drill portion are integrally cast. ,
(B) A plurality of the helical excavation blades are intermittently provided in the longitudinal direction of the support rod, and the diameter of the spiral excavation blades is moved away from the front end of the support rod in the rear end direction. And the tip and outer peripheral edge of each spiral excavation blade in the entry direction are sharply formed,
(C) The drill portion is formed in a cone shape, and has a substantially linear cutting blade from the distal end portion to the proximal end portion of the cone,
(D) Ri Oh provided nearest upper side constricted portion of the drill portion of the support rod,
(E) The tip of the spiral excavation blade on the most tip side of the support rod is provided in the constricted portion,
An underground anchor characterized by that. Supporting rod, spiral digging edge and drill part is cast in spheroidal graphite cast iron, the ground anchor according to claim 1, characterized in that it is upper bainite processing.

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