JPS607438Y2 - enlarged bit - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an enlarged bit for a spiral auger, which is used when sinking a foundation pile such as a hollow concrete column (pile) while being dug in the middle with a spiral auger.

When constructing conventional foundation piles, for example,
As described in Japanese Patent No. 8047, an enlarging tool is rotatably attached to the lower end of a spiral auger in a manner inclined with respect to the axis of the auger, and the enlarging tool closes by its own weight.
The expansion is achieved by the earth pressure applied to the lower surface of the expander and the force acting on the inclined lower surface of the expander due to the rotational force of the spiral auger. There was a problem in that it was not possible to confirm whether or not the diameter had expanded.

The present invention solves the above-mentioned drawbacks by inserting a spiral auger with an enlarged bit attached to the lower end into the hollow part of the foundation pile. When inserting the spiral auger into the hollow part of the foundation pile, the expanding tool is fixed in a reduced state, and during excavation, the expanding tool is reliably expanded and fixed to the specified outer diameter using an expanding bit. It provides:

To explain in detail the embodiment shown below, FIG. 1 is a front partial cross-sectional view of the auger and the lower end of the pile showing the open/closed state of the enlarged bit.
The structure is such that a bit 2 is connected to the lower end of the pile through the hole, the bit 2 is made to protrude from the lower end of the pile, the bit 2 is opened and closed, and the lower part of the pile 1 is drilled into a hole having the same diameter as S.

3 is a joint part that joins the auger shaft 4 and the bit 2;
An inner cylinder 5 of a certain length is integrally fixed coaxially with the lower end of the joint part 3, and furthermore, an excavating blade 6 is provided integrally and downwardly protruding from the lower end.

At the top of the excavating blade 6 is a horizontally expanding wing support arm 8.
are provided so as to correspond to the number and position of enlarging tools 12, which will be described later.

Reference numeral 9 denotes an outer cylinder that is rotatably fitted around the inner cylinder 5 between the joint part 3 and the excavation blade 6, and a bracket 10 and a pin 11 are connected to the outer circumferential intermediate position of the outer cylinder 9. The upper end of the enlarging tool 12 is pivotally supported so that it can be opened and closed downward and radially.

The lower part of the enlarging tool 12 is configured to interfere with a tapered block 13 provided upwardly protruding from the tip of the support arm 8, thereby maintaining the opening/closing operation and the open/closed state.

That is, the taper block 13 protrudes from the arm 8 in the excavation rotation (normal rotation) direction of the auger and is fixed to the arm 8 so as to form a hook shape in plan view.
Its upper surface also forms a constant slope in the normal rotation direction.

FIG. 2 is a cross-sectional view taken along line A-A in FIG. On the other hand, on the outer peripheral surface of the upper end of the outer cylinder 9, stoppers 14 and 15 are protruded at a constant angular interval so as to come into contact with the engagement protrusion 7. Stopper 1
The outer cylinder 9 can rotate within the range between 4 and 15 around the axis.
The outer cylinder 9, that is, the enlarged bit, also rotates at the same time when the outer cylinder 9 rotates beyond the rotation angle.

The relative free rotation of the auger shaft 4 regulated by the stoppers 14 and 15 is for opening and closing the enlarger 12 by the taper block 13 as described below.

That is, as shown in FIGS. 3 and 4 A and B,
When the auger is rotated in the normal direction (arrow a) with the enlarging tool 12 closed by its own weight, the lower end of the taper block 13 attached in a hook shape at the tip of the arm 8 will touch the outer surface of the enlarging tool 12. At the same time, the arm 8 hits the side surface on the reverse direction side, and the blade 12 remains closed and locked (see solid line in FIG. 1, FIG. 3, and FIG. 4A).

To open the wings 12 from this state and lock them, first make the lower end of the bit protrude a certain length from the lower end of the pile 1 so that the inner diameter of the pile does not interfere with opening and closing, and then turn the auger in reverse (as shown by the arrow). direction) to unlock the blade 12 by the arm 8 and block 13 to make it free, then push the auger into the soil and use the earth pressure at that time to open the blade 12 to a certain angle, and then rotate the auger in the normal direction again. As a result, the lower end of the sloped surface of the tapered block 13 is made to submerge into the inner surface side of the blade 12, and the blade 12 is pushed upward by the movement of the sloped surface in the normal rotation direction to open it to its upper limit.

At approximately the same time that the blades 12 open to the upper limit regulated by a stopper (not shown), the engagement protrusion 7 hits the stopper 14, causing the auger shaft 4 and the blades 12 to rotate together and become ready to withstand excavation resistance.

An imaginary line in FIG. 1 and FIG. 4B show the relationship between the blade 12 and the tapered block 13 at this time.

To close the blade 12 again from the above state, the auger is reversed by a certain angle, the lock is released, and the auger is pulled up, and the blade 12 is closed by its own weight.

5A and 5B are partial front sectional views showing the enlarged bit in the fully closed position and the fully opened position in another embodiment of this invention; in this embodiment, the pin that pivotally supports the blade 12 is 11 is not installed horizontally, but is installed at an angle so as to descend at a constant angle in the normal rotation direction,
As a result, the blade 12 does not simply open and close up and down, but rotates diagonally according to the inclination of the pin, and the blade 12 opens and closes in response to the auger rotation angle compared to the case shown in FIG. This has the effect of increasing the angle ratio.

In addition, although the above embodiment shows a structure in which the enlarger is locked even in the closed state, the closed state is ensured by the own weight of the enlarger, so it is not necessarily necessary to lock it in normal use. do not have.

This invention produces concrete effects such as the result method constructed as described above.

(1) Since the expander is fixed by the expander support arm and the tapered block, when inserting the bit into the antibiotic cavity, the inner peripheral surface of the pile will not be damaged by the blade tip.

(2) Use the above-mentioned arm etc. to securely hold the enlarging tool at a predetermined angle (
The diameter of the foundation pile can be expanded to a larger diameter, which greatly speeds up the work of laying foundation piles and greatly improves work efficiency.

(3) Since the expanding tool can be reliably expanded to a predetermined diameter, a predetermined supporting force can be reliably obtained by pouring out a root hardening material such as cement milk from the tip of the auger.

In addition to the embodiments described above, for example, a stopper and an engaging protrusion for regulating the rotation of the inner cylinder and the outer cylinder may be provided on either side of the inner or outer cylinder, and the hollow part of the auger of the structure of this invention may be used. Of course, a hardening agent such as cement milk can be poured out using the same method.

[Brief Description of the Drawings] Fig. 1 is a partial front sectional view showing the structure of the enlarged bit of this invention, Fig. 2 is a sectional view taken along line A-A in Fig. 1, and Fig. 3 is Fig. 1 B.
-B is a sectional view, FIGS. 4A and 4B are partial perspective views showing the enlargement tool in its open/closed state and its locked state, and FIGS. It is a front view. The symbols in the figure indicate the following parts.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. An inner cylinder that is attached to the lower end of an auger that is sunk while excavating a hollow concrete column etc. and rotates together with the auger, and an outer cylinder that is fitted onto the outside of the inner cylinder so as to be rotatable at a certain angle. The upper end of the excavating enlarging tool is swingably supported by a pin on the outer periphery of the outer cylinder, and an enlarging wing support arm that opens the enlarging tool by the relative rotation of the inner and outer cylinders is mounted on the inner circumference of the outer cylinder. An enlargement bit characterized by being installed in a tube. 2. Utility model registration claim No. 2, characterized in that the tip of the expanding wing support arm is hook-shaped, and a tapered block having an inclined surface facing in the normal rotation direction of the auger is formed or attached as the hook-shaped portion. Expansion bit as described in Section 1. 3 Utility model registration claim 1 characterized in that the expanding wing support pin is inclined at a certain angle with respect to the horizontal direction
Expansion bits listed in section.