JPS6346546Y2 - - Google Patents

Description

[Detailed explanation of the invention] "Industrial application field" This invention efficiently makes holes for bulbs created to increase the bearing capacity of piles buried by various methods such as medium excavation method and rotary burying method. It concerns an enlarged auger head that can dig.

``Prior Art'' Various enlarged auger heads have been proposed for the purpose of excavating holes for bulbs of this type, with some success. For example, in the construction method and construction device for expanding piles disclosed in JP-A-53-1906, a main expanding blade is pivotally mounted on the shaft of an auger head, and a sub-expanding blade is pivotally connected to this main expanding blade. The main and sub-expanding blades are configured to expand and contract due to the forward and reverse rotation of the auger head and the earth pressure resistance around the main and sub-expanding blades. In addition, in the self-weight type two-stage expansion bit of Utility Model Publication No. 54-44962, an outer cylinder that can be raised and lowered is provided in the inner cylinder of the expansion bit, and an expansion blade pivotally attached to this outer cylinder is used to raise and lower the outer cylinder and around the expansion blade. It is configured to expand and contract through the earth pressure resistance.

``Problems to be Solved by the Invention'' As detailed above, conventional expanding bits are configured to expand and contract by the earth pressure resistance applied to the expanding blades and blades, and the forward and reverse rotation of the auger head. However, this earth pressure resistance utilizes the earth pressure resistance of soil that has already been excavated or loosened with the tip claw, so the expanding blade etc. does not necessarily expand or contract reliably, and sometimes remains reduced in diameter. Its movements were unstable. In addition, all of them have complicated structures and operations, are difficult to operate, and are prone to failure.
There were other problems such as the troublesome maintenance.

``Means for solving the problem'' Therefore, the present invention is designed to reliably catch the earth pressure resistance with the digging claw at the tip, thereby reliably expanding and contracting the expansion/contraction bit via the rotating member and operating rod. The gist of this is that a pair of expansion and contraction bits are installed in a sheath tube that is integrated with the upper circumferential surface of the main body that has a press-fit hole through a square-shaped bracket, and an operation that controls the expansion of the expansion and contraction bits is provided. The rod is provided on a rotating member having a pair of spiral blades loosely fitted to the lower part of the main body, and the digging claw of the spiral blade provided on the rotating member is located ahead of the coupling provided at the lower end of the main body. By using the earth pressure resistance received by the digging claw of the spiral blade to rotate the main body in a state where the rotating member and operating rod are stationary, the expansion/retraction bit is expanded through the operating lever in the stationary state. When it is opened and rotated forward, the engagement between the operating rod and the expansion/contraction bit is released, and the diameter is reduced through the earth pressure resistance applied to the expansion/contraction bit.

``Operation'' The enlarged auger head of the present invention is fitted to the tip of an auger shaft (not shown), and in the normal underground excavation method, for example, it is inserted into the hollow interior of piles such as hollow steel pipe piles and concrete piles to sequentially excavate. , the piles will be sunk.
When the pile reaches a predetermined position and a hole for the bulb is to be excavated at its tip, the auger shaft is reversed (counterclockwise) as shown in FIG. 3A, and the main body 1 is rotated in the same direction. In this state, the spiral blades 9, 9a and the excavating claws 10, 10a at their tips are subjected to earth pressure resistance, so the rotating member 8 remains in the so-called stationary state. As a result, the operating rods 11, 11a in a stationary state, which are erected on the rotating member 8, enter between the expansion/contraction bits 4, 4a and the sheath tube 2, and the expansion/contraction bits 4, 4a move forward in the circumferential direction. Since the expansion/contraction bits 4, 4a gradually expand using their pivot parts 5, 5a as fulcrums, they reach their maximum diameter as shown in FIG.
The operating rods 11, 11a are restricted by the brackets 3, 3a, and the bases of the expansion/contraction bits 4, 4a are restricted by the hanging portions 3', 3'a of the brackets 3, 3a, respectively, so that they do not enter or expand. Therefore, by excavating while maintaining this expanded state, a hole for the bulb with a diameter larger than the pile diameter will be created, so a coagulating material such as cement milk or mortar is pumped through the press-in hole 6 and mixed with the excavated soil. . After that, the auger shaft is rotated in the normal direction (clockwise), and the main body 1 is rotated in the same direction. In this state, the spiral blades 9, 9a, the excavating claws 10, 10a, etc. at the tip are subjected to earth pressure resistance, so the rotating member 8 remains in the same state, and is in a so-called stationary state. As a result, the operating rods 11, 11 in a stationary state that are erected on the rotating member 8
A is removed from between the expansion/contraction bits 4, 4a, which rotate in the normal direction at the same time as the main body 1, and the sheath tube 2, and the expansion/contraction bits 4, 4a
is released from the engagement with the operating rods 11, 11a, and due to the earth pressure resistance applied to the expansion/contraction bits 4, 4a themselves, the diameter is gradually reduced using the pivot parts 5, 5a as fulcrums, and the diameter reaches the minimum diameter as shown in Figure A. Then, the enlarged auger head is removed from the hollow interior of the pile and raised to the ground.

"Embodiment" The drawings show one embodiment of the present invention, in which 1 is the main body of the expanding auger head which is fitted to the auger shaft (not shown), and a sleeve tube 2 is provided on the upper part of this main body 1, leaving only a fitting portion 1a for the auger shaft. It is also possible to directly extend the sleeve tube 2 from the main body 1 without providing the sleeve tube 2, making it a large-diameter portion. And at the lower part of this sleeve tube 2, expansion/contraction bits 4, 4a, which have approximately the same curvature as the sleeve tube 2, are pivotally supported by pivot portions 5, 5a via brackets 3, 3a shaped like a square, which are attached in an approximately symmetrical relationship.
a has an expansion/contraction bit 4, 4a, a vertical part 3' for impact stopping,
The expansion/contraction bits 4, 4a are provided.
The tip of the sleeve 2 has an inclined surface cut from the outside to the inside in order to make it easier to insert the operating rods 11, 11a described later, and its length is ideally about 1/4 of the length of the outer circumferential surface of the sleeve tube 2 as shown in the figure, but the design can be changed as appropriate depending on the case.
Reference numeral 6 denotes a pressure-feed hole for pressure-feeding cement milk, mortar, etc., which is provided through the main body 1. Reference numeral 7 denotes a spiral blade provided on the sleeve pipe 2. Reference numeral 8 denotes a rotating member loosely fitted to the lower part of the main body 1. A pair of spiral blades 9, 9a are wound around the outer periphery of the rotating member 8.
The excavation claws 10, 10a provided at the tips of the blades 9, 9a are configured to be positioned forward of a coupling provided at the lower end of the main body 1, which will be described later.
The tip of the operating rod 1a is located above the expansion/contraction bits 4, 4a, and moves along the circumferential surface of the sleeve tube 2 by the rotation of the rotating member 8.
The expansion and contraction bits 4, 4a are forcibly expanded by the use of the couplings 1, 11a. The reference numeral 12 denotes a coupling provided at the lower end of the main body 1, and by attaching and detaching this coupling 12, the rotating member 8 can be replaced, and the spiral blades 9, 9a, etc. can be repaired, and various pile diameters can be accommodated. The reference numeral 13 in the figure denotes a grease nipple.

``Effects of the invention'' As detailed above, the present invention provides a pair of expansion/contraction bits through a square-shaped bracket at approximately the center of the circumferential surface of the main body that is fitted onto the auger shaft, and allows the expansion/contraction bits to expand. The controlling operating rod is provided on a rotating member loosely fitted to the lower part of the main body, and when the main body is reversed, this rotating member is held stationary by a digging claw of a spiral blade provided thereon, and the operating rod moves in the same manner as this rotating member. The expansion/contraction bit is expanded through the screw, and when the main body rotates normally, the diameter of the expansion/contraction bit is reduced by the earth pressure resistance applied to the expansion/contraction bit itself. The expansion/contraction bit is reliably expanded by keeping it in a stationary state and reversing the main body. Therefore, the instability factor caused by the expansion of the expansion blade due to the earth pressure resistance caused by excavation or the like can be eliminated, and the reliability of expansion is achieved as described above. Further, the expansion of the expansion/contraction bit is due to a rotating member loosely fitted into the main body, a stationary means using a digging claw of a spiral blade provided on this rotating member and an operating rod, and the reversal of the expansion/contraction bit as the main body is reversed. , reliability of expansion and simplicity of work are achieved. Furthermore, since the structure is simple and mechanically unreasonable, the expansion/contraction bit expands/contracts smoothly and has fewer failures.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; FIG. 1 is a front view, FIG. 2 is a vertical sectional view, and FIGS. be. DESCRIPTION OF SYMBOLS 1... Main body, 2... Sheath tube, 3, 3a... Bracket, 4, 4a... Expansion bit, 5, 5a... Pivot part, 8... Rotating member, 9, 9a... Spiral wing, 1
0, 10a...Drilling claw, 11, 11a...Operating rod, 12...Coupling.

Claims (1)

[Scope of utility model registration request] A pair of expansion/contraction bits are installed via a bracket with a vertical part at approximately the center of the circumferential surface of the main body having a press-fit hole,
An operating rod that controls the expansion of the expansion/retraction bit is provided on a rotating member having a pair of helical blades that is loosely fitted into the lower part of the main body, and a digging claw of the helical blade provided on the rotating member is provided on the lower end of the main body. It is configured to be located ahead of the coupling coupling, and by using the earth pressure resistance received by the digging claw of the spiral blade to reverse the main body with the rotating member and operating rod stationary, it is possible to operate in a stationary state. An expanding auger head characterized by expanding an expanding/contracting bit through a rod, and contracting the diameter through earth pressure resistance applied to the expanding/contracting bit by normal rotation of the main body.