JPS6129830Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a bottom-expanding rotary bit device applied to a reverse circulation drill, and particularly to the structure of the bottom-expanding wing portion thereof.

In recent years, as a cast-in-place concrete pile construction method, as illustrated in Fig. 1, a round hole b with a single diameter φ ₁ is dug from the ground a, and a hole b with a diameter of φ 1 is enlarged at the bottom with an inclination angle θ and a maximum diameter φ ₂ . Excavate a widening hole c that will satisfy the following conditions. The bell-shaped widening trench construction method is often adopted, and various excavation tools for this construction have also been proposed. FIGS. 2 and 3 show a known rotary bit device for expanding the bottom which was already disclosed by the present applicant in Japanese Utility Model Application Publication No. 52-161901. This device consists of a central tube 1 with flanges 1a and 1b formed at the upper and lower ends, and a central tube 1.
The expanded bottom wing 6 is attached to a support frame 5 fixed to the upper part of the center tube so as to be able to swing around a pin 7, and the sliding member 9 is fitted into a guide portion 1c provided in the middle part of the center tube 1. Attach the member 9 to the middle part of the expanded bottom wing 6 with the pin 1.
4 and 15, a stopper 13 pinned to the guide portion 1c so as to be vertically adjustable in order to limit the upward movement of the sliding member 9, and a bracket provided at the top of the central tube 1. pin 12 to 16
, the piston rod 11a is connected to the sliding member 9, and the hole 5 of the support frame 5 is attached.
a, and an airfoil-shaped tip bit 2 that is attached to the lower end of the center tube 1 (via the joint tube 1e in this example) and has a suction port 4 in the center, The tip bit 2 and the expanded bottom blade 6 have cutters 3 and 8, respectively, and an extension blade 2a can be attached to each blade of the tip bit 2 to accommodate various shaft diameters (φ ₁ in Fig. 1). The inclined hole excavation portion of the expanded bottom blade 6 consists of an upper expanded bottom blade 6a and a lower expanded bottom blade 6b which can be separated, and both are connected by bolts to a length adjustment expanded bottom blade 6c interposed between them. has been done. Also, the lower bottom expansion wing 6b
A vertical bottom-expanding wing 6d for excavating the vertical part of the bottom-expanding hole is bolted to the lower part of the bottom-expanding hole.

In this device, when the drill pipe connected to the center tube 1 by the flange 1a rotates, the center tube 1, the tip bit 2, and the bottom expansion blade 6 rotate together, and the cutters 3 and 8 perform drilling. When the bottom is not expanded, the bottom expansion blade 6 is closed. On the other hand, when the piston rod 11a of the hydraulic cylinder 11 is retracted by pressure oil fed from the ground, the sliding member 9
is pulled up, thereby causing the expanded bottom wing 6 to swing outward via the link 10, and its upper limit position is regulated by the stopper 13, whereby the inclination angle θ (first Figure) is determined. By selecting the position of this stopper 13, the maximum diameter (expanded portion diameter φ ₂ ) of the expanded bottom blade 6 when the expanded bottom is expanded can be set variously. In particular, this device allows the length of the expanded bottom blade 6 to be adjusted,
And by changing the position of the stopper 13,
The feature is that various enlarged bottom diameters can be obtained.

However, the configuration of this wide-bottomed wing has the following problems. In Fig. 4, the solid line A shows the state where the expanded bottom blade 6 is not extended and the expanded bottom diameter φ _A is at its maximum, and the dotted line B shows the expanded bottom blade 6 is extended and the expanded bottom diameter φ _B is the maximum. As shown in the figure, when the expanded bottom wing 6 is extended, the nodes (pins 14, 15) of the link 10 are lower than when they are not extended, so φ _A > φ _B. I got used to it,
If the same link 10 is used, the original purpose of bottom expansion cannot be achieved. Furthermore, the degree of change in the diameter of the expanded bottom portion with respect to the change in the expanded bottom blade θ is also greater before the expanded root blade is extended than after the extension, which also means that the original purpose of the expanded bottom portion has not been achieved.

In addition, the stroke of the hydraulic cylinder 11 is determined taking into consideration the case where the expanded bottom blade 6 is extended.
In the state before the expansion wing 6 is extended, the specifications are excessive.

Furthermore, in order to obtain a larger diameter of the enlarged bottom part after extension than before extension of the enlarged bottom wing, another link is required, which also causes the hydraulic cylinder 11 to have an excessive specification, which is uneconomical. It is the composition.

Furthermore, the following problems occur. Normally, when excavating using a bottom-expanding bit that swings the bottom-expanding blades 6 using the pin 7 as a fulcrum, the bottom can be expanded by simply expanding the bottom-expanding blades while keeping the bit stationary in the vertical direction. cannot be directly known on the ground. For this reason, in order to know whether the expanded bottom wing is fully opened, a detector detects the expansion and contraction state of the hydraulic cylinder that expands the expanded bottom wing, and the detection signal is sent to the ground, allowing the recorder to depict the expanded bottom state. The method is known.
However, with the expanded bottom blade extension mechanism described above, the change in the inclination angle θ of the expanded bottom blade with respect to the change in the stroke of the hydraulic cylinder differs depending on whether the expanded bottom blade is extended or not. Some corrections were necessary.

The object of the present invention is to provide a rotary bit device for bottom expansion which is constructed so that the bottom expansion blades can be extended, which can completely solve the various problems mentioned above, namely:
It is an object of the present invention to provide a device that can increase the diameter of the enlarged bottom portion without changing the hydraulic cylinder or the link, and is advantageous in detecting the diameter of the enlarged bottom portion.

A feature of the present invention is that the expanded bottom blade is configured by an upper expanded blade whose upper end is connected to a support frame and a lower expanded root blade that is connected to the upper expanded blade so that it can be positioned relative to the upper expanded blade in the longitudinal direction, and By connecting the and the sliding member with a ring, we created a structure in which the distance between the node between the expanded bottom blade and the link and the swing fulcrum of the expanded bottom blade is always constant regardless of changes in the length of the expanded bottom blade. be.

The details of the present invention will be explained below with reference to FIGS. 5 to 8. 5 and 6 show an embodiment of the present invention, in which FIG. 5 shows a state in which the expanded bottom wing 60 is not extended, and FIG. 6 shows the configuration in an extended state. Fifth
6, the same reference numerals as those in FIGS. 2 to 4 are provided to perform the same or equivalent functions. The expansion blade 60 includes an upper expansion blade 60a and a lower expansion blade 60b provided to excavate the inclined part of the expansion hole, and a vertical expansion blade 60c bolted to the lower end of the lower expansion blade 60b, taking into consideration the extension of the vertical part. It consists of an extension wing 60d provided as an extension wing. The upper expanded base wing 60a is attached to a support frame 5 fixed to the upper part of the center tube 1 so as to be swingable in the radial direction by a pin 7, and the intermediate portion of the upper expanded base wing 60a and the sliding member 9 are as follows. Link 10 and pin 1
4 and 15. Further, bolt holes are drilled in the upper expanded base wing 60a and the lower expanded base wing 60b for changing the connection position in the length direction of each other, and the relative positions in the length direction of the two are changed and the bolts 20 are used to connect them. By this, the enlarged hole c in Fig. 1
The total length of the excavated part of the slope can be changed.

In the state shown in FIG. 5 before the expansion wing is extended, the upper end of the lower expansion wing 60b is connected to the midsection of the upper expansion wing 60a with a bolt 20, and the lower end of the upper expansion wing 60a is connected to the midsection of the lower expansion wing 60b with a bolt. Combined at 20.

On the other hand, in the expanded bottom wing extended state shown in FIG. In addition, in order to align the position of the tip bit 2 with the lower end position of the vertical expansion wing 60c, the lower end of the center tube 1c and the tip bit 2 are aligned.
A connecting pipe 1e is provided between the two.

As described above, in the present invention, by connecting the upper expanded bottom wing and the sliding member with a link, the node of the expanded bottom wing 60 with the link 10 (the position of the pin 15) can be adjusted before and after the extension of the bottom expanded wing 60. ) and the expanded bottom wing 60
Since the distance between the link 10 and the swing fulcrum (the position of the pin 7) remains the same, even if the link 10 and the hydraulic cylinder 11 are the same, the bottom-expanding effect can be obtained. That is, the change in the diameter of the enlarged bottom part with respect to the inclination angle θ of the enlarged bottom wing 60 after extension is larger than that before extension, and the diameter of the enlarged bottom part at the minimum inclination angle of the link 10 is the same as that after extension in FIG. It is also clear that this is larger than before the extension shown in FIG. 5, and the purpose of widening the bottom is achieved. In addition, since the inclination angle θ of the expanded bottom blade 60 is the same with respect to the stroke of the hydraulic cylinder 11 whether or not the expanded bottom blade 60 is extended, the expanded bottom shape can be easily formed on the ground by simply detecting the stroke of the hydraulic cylinder. can be judged. In addition, in this embodiment, the length of the expansion blade is changed by changing the connecting position of the upper expansion blade 60a and the lower expansion blade 60b, so the constituent members of the expansion blade are of one type. It has the advantage of being Although this embodiment shows an example in which the length of the expanded bottom blade can be selected from two types, it is also possible to select three or more types.

7 and 8 show another embodiment of the present invention, in which the link 10 is
The lower end surface of the upper expanded base wing 61a connected to the lower expanded base wing 61b ₁ or 61b ₂ (61b ₂
is larger than the length of 61b ₁ ), butt the top surfaces together,
Joint plates 21a and 21b are applied to the plate surfaces of both wings and are connected with bolts 22. In this embodiment as well, the effect of enlarging the diameter of the enlarged bottom portion can be obtained in the same manner as described above, and the shape of the enlarged bottom portion can be easily determined as described above.

In the above embodiment, the upper limit position of the sliding member 9 is changed by providing the stopper 13 on the upper part of the guide part 1c and changing its vertical position, thereby determining the diameter of the enlarged bottom part (i.e., the diameter of the enlarged bottom part is determined). However, the stopper 13 is provided below the fitting position of the sliding member 9 in the guide portion 1c, and by extending the hydraulic cylinder, the expansion wing can be expanded. may be expanded.

As described above, the present invention provides an upper bottom expansion rotary bit device in which the bottom expansion blades are swingably attached to a support frame fixed to the upper part of the center tube and configured to extend the bottom expansion blades. By connecting the blade and the sliding member with a link, the distance between the node of the expanded-bottomed blade with the link and the swing fulcrum of the expanded-bottomed blade remains constant regardless of the length of the expanded-bottomed blade, resulting in the following effects: can be given.

(1) The change in the diameter of the expanded bottom part due to the change in the inclination angle of the expanded bottom blade becomes larger when the length of the expanded bottom blade is long. can get.

(2) Since the inclination angle θ of the expanded bottom wing with respect to the stroke of the hydraulic cylinder is constant regardless of the length of the expanded bottom wing, the expanded bottom shape can be easily determined on the ground simply by detecting the stroke of the hydraulic cylinder.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the shape of a hole drilled by a bottom-expanding rotary bit device, and FIG. 2 is a partially cutaway front view showing a known bottom-expanding rotary bit device having a bottom-expanding blade extension mechanism. FIG. 3 is a plan view of the same, FIG. 4 is an explanatory diagram explaining the problem, FIG. Figure 6 is a partially cutaway front view showing a state in which the expanded bottom wing is lengthened in this embodiment;
8 shows another embodiment of the present invention, and FIG. 7 is a partial view of the expanded bottom wing showing the expanded bottom wing in a shortened state.
FIG. 8 is a partial view showing a state in which the expanded bottom wing is lengthened. 1... Central pipe, 1c... Guide section, 1e... Joint pipe, 2... Tip bit, 3, 8... Cut, 4...
... Suction port, 5 ... Support frame, 6, 60 ... Expansion wing,
7, 12, 14, 15...pin, 9...sliding member, 10...link, 11...hydraulic cylinder, 1
3... Stoppa, 20, 22... Bolt, 21
a, 21b... joint plate, 60a... upper expanded base wing,
60b...Lower expanded base wing, 61a...Upper expanded base wing,
61b ₁ , 61b ₂ ...lower expansion wing.

Claims (1)

[Scope of utility model registration request] An airfoil-shaped tip bit, which has a suction port at the center of the lower end that sucks up earth and sand together with water, is detachably attached to the lower end of the central tube that is detachably connected to the drill pipe of the reverse circulation drill. A wide-bottomed wing is attached to a support frame fixed to the upper part of the center pipe so as to be swingable so as to spread downward, and in a closed state, the wing is positioned in the gap between the tip bits, and is provided in the middle of the center pipe. An upper limit or lower limit position setting member for the sliding member attached to the guide portion, which connects a sliding member fitted to the guide portion so as to be slidable up and down by a hydraulic cylinder and the middle of the expanded bottom wing via a link. In the rotary bit device for bottom expansion, the inclination angle of the bottom expansion blade is determined and the length of the bottom expansion blade can be changed. Consisting of an upper expanded base wing and a lower expanded base wing that is coupled to the upper expanded base wing so that the relative position in the length direction can be adjusted, and
By connecting the upper expanded-bottom blade and the sliding member with a link, the distance between the swing fulcrum of the expanded-bottom blade and the node between the expanded-bottom blade and the link remains constant regardless of changes in the length of the expanded-bottom blade. A rotary bit device for expanding the bottom.