JP3662647B2 - Expansion head for excavation - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an expansion head for excavation provided at the lower end of an excavation rod.
[0002]
[Prior art]
As shown in FIG. 1, the excavator for excavating the ground has a drive unit 5 that slides up and down on a guide rail 4 on the front surface of a leader mast 3 that is vertically supported by a base machine 1 via a stay 2. A wire 7 supported freely and wound around a sheave 6 at the top of the drive unit 5 is guided to a winch 9 on the base machine 1 via sheaves 8, 8 at the upper end of the leader mast 3. The drive unit 5 is moved up and down by winding and lowering, and a drive source such as a motor and a speed reducer and a swivel 10 for injecting a chemical solution are mounted in the drive unit 5, and an output shaft of the drive source The upper end of an excavating rod 11 such as an auger screw is connected to the end.
[0003]
The excavation rod 11 has a excavation head 12 at the lower end, and the excavation rod 11 is rotated by the drive unit 5 to excavate the ground with the excavation head at the lower end, drill a hole to create a pile, and create an underground wall. It is possible to perform necessary work such as.
[0004]
By the way, when excavating the ground with the above excavator and simultaneously injecting chemicals such as cement milk and mortar and kneading with excavated earth and sand to create an underground pile, in order to increase the bearing capacity of the pile, It is practiced to create a bulb by expanding the root part.
[0005]
In order to perform the expansion digging as described above, an magnifying head is used that allows the digging to be performed by increasing the substantial turning radius of the digging blade of the digging head when excavated to a predetermined depth.
[0006]
Conventional expansion heads are generally those that open and close the excavating blade using the resistance of earth and sand caused by forward and reverse rotation during excavation, or those that open and close using the inner surface of the hollow pile, or see JP-A-7-4169. And the like that are opened and closed using an operating mechanism.
[0007]
[Problems to be solved by the invention]
However, there is a problem that an arbitrary diameter cannot be increased with the use of the resistance of the earth and sand, and an applicable construction method is limited with the use of the inner surface of the hollow pile. Furthermore, since the opening / closing operation mechanism of the excavating blade is exposed to the outside, the one described in the above publication may become inoperable due to clogging of earth and sand during excavation.
[0008]
[Means for Solving the Problems]
An object of the present invention is to provide an enlargement head for excavation that makes it possible to reliably open and close an excavating blade in the ground, and is supported by a drive unit of an excavator so that it can be moved up and down. And an operation rod penetrating the inside of the excavation rod connected to the drive unit, and a pair of left and right enlarged excavation blades supported at the lower end of the excavation rod so as to be openable and closable. The lower end support portion is pivotally attached in a vertical plane by the pivot at a position separated from the axis of the operation rod, and is pivotally attached to the lower excavation blade. A contact portion at the lower end of the operating rod is in contact with both of the enlarged excavating blades on the upper surface therebetween, and when the operating rod is pulled up, the left and right enlarged excavating blades are expanded.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described below with reference to embodiments shown in the drawings.
[0010]
The enlarged head 13 according to the present invention is a polygon connected to the lower end of the excavating rod 11 as shown in FIG. 2 as a front view with a partial cross section, as shown in FIG. 3 as a side view, and as shown in FIG. (Hexagonal) cross-section joint portion 14, a short hollow rod portion 15 provided continuously to the lower portion of the joint portion 14, and a support portion 17 provided continuously to the lower end of the rod portion 15 and having a bit 16 at the lower end. A spiral blade 18 is provided on the outer periphery from the joint portion 14 to the upper portion of the support portion 17, and the joint portion 14, the hollow rod portion 15, and the support portion 17 are substantially one end of the lower end of the excavation rod 11. The part is configured.
[0011]
The support portion 17 is formed with slit-shaped bearing portions 19, 19 from the lower end at equidistant positions from the center thereof. These bearing portions 19, 19 have a base portion of a pair of left and right digging blades 20, 20. 20a and 20a are fitted and pivotally attached to the central wall portion 22 by pivots 21 and 21 at positions equidistant from the center of the support portion 17, respectively, and the base portions 20a and 20a partially overlap each other. Thus, the expanded excavating blades 20 and 20 are opened and closed between a horizontally expanded posture (open position shown by a solid line in FIG. 1) and a downward rotated posture (closed position shown by a chain line in FIG. 1). ing.
[0012]
As shown in FIG. 5, coil springs 23, 23 are wound around the pivots 21, 21, one end of which is fixed to the support portion 17 side and the other end is fixed to the enlarged excavation blade 20 side. The digging blades 20 and 20 are biased in the expanding direction. The springs 23, 23 need only have strength to overcome the dead weight of the expanded excavation blades 20, 20 at a minimum.
[0013]
At the center of the upper part of the joint part 14, the hollow rod part 15, and the support part 17, the upper part penetrates the excavation rod 11 and the swivel device 10 of the drive part 5, and the upper end is supported by the vertical movement operation mechanism 24. A lower portion of the operation rod 25 is inserted, and a horizontal bar-shaped contact portion 26 is provided at the lower end of the operation rod 25, and this contact portion 26 is a base end portion 20 a of the enlarged excavation blades 20, 20. , 20a is abutted against the upper surface of the pivots 21 and 21 at a slight distance from each other, and the lowering limit of the operating rod 25 is determined by the abutting portion 26 coming into contact with the stopper portion 27 formed on the support portion 17. The enlarged excavation blades 20 and 20 at this time are configured so as to be closed to the minimum width. The distance L between the distal ends of the enlarged excavation blades 20 and 20 at the time of closing is set to be approximately equal to the outer diameter of the spiral blade 18.
[0014]
A compression spring 28 is built in the joint portion 14, the upper end of the spring 28 is in contact with a spring receiver 29 of the operating rod 25, and the lower end is in contact with a spring receiver 30 in the support portion 17. The rod 25 is constantly biased to return upward.
[0015]
FIG. 8 shows an example of the vertical movement operation mechanism 24 of the operation rod 25. As shown in FIG. 6, the center hole type jack 31 is placed in the vertical position on the upper part of the swivel device 10, as shown in FIG. An upper portion of the operating rod 25 is passed through a ram 33 that is mounted and fixed to the piston 32 of the jack 31, and the ram is interposed between a head 34 at the upper end of the operating rod 25 and a flange 36 at a position below it. 33, and thrust bearings 37 and 38 are interposed between the head 34 and the upper end of the ram 33 and between the flange 36 and the lower end of the ram 33, respectively. Note that the operation rod 25 does not necessarily have to be connected when the excavation rod 11 is added.
[0016]
Hydraulic jacks 39 and 40 are connected to the upper and lower portions of the jack 31, the upper hydraulic piping 39 is connected to a hydraulic pump 42 via a hydraulic pressure detecting device 41 having a cylinder structure, and the lower hydraulic piping 40 is directly connected to the hydraulic pump. 42.
[0017]
The swivel device 10 is an existing one, and supplies chemical liquid such as cement milk and mortar from the injection port 43, passes through the joint 15 and the pipe 15a through which the operation rod 25 passes through the hollow rod 15; A chemical solution is ejected into the ground from a gap 44 (shown in FIG. 3) between the support portion 17 and the upper surfaces of the enlarged excavating blades 20 and 20, and the peripheral portion is washed by the ejection of the chemical solution. .
[0018]
Next, the operation will be described.
[0019]
The base machine 1 is moved to the position to be drilled, the excavation rod 11 connected to the drive unit 5 is positioned at the drilling position, and then the drive unit is driven while the excavation rod 11 is rotationally driven by the motor in the drive unit 5. 5 is gradually lowered to advance the hole. At this time, the operating rod 25 is in the lowest lowered position as shown in FIG. 6, and the enlarged excavating blades 20 and 20 are closed. Further, a chemical solution is supplied from the beginning of excavation and injected into the ground through the gap 44.
[0020]
When excavation has progressed to a predetermined depth and it has been grasped by a depth meter or the like that the depth has been reached, the hydraulic pump 42 is driven and pressure oil is supplied to the lower side of the jack 31 through the hydraulic pipe 40. As a result, the piston 32 is pushed up, and the operation rod 25 is pulled up through the ram 33 while also applying the force of the compression spring 28.
[0021]
As the operation rod 25 is lifted, the restriction of the expansion digging blades 20 and 20 is released, so that the springs 23 and 23 of the pivots 21 and 21 of the expansion digging blades 20 and 20 and the earth pressure are arbitrarily selected according to the amount of lifting of the operation rod 25. The diameter gradually expands to the enlarged diameter, and the state shown in FIG. 7 is obtained. If excavation is continued during this time, the ground at that position is gradually expanded and kneaded with the chemical solution supplied through the swivel position 10 to form a large bulb.
[0022]
After the bulb formation, pressure oil is supplied to the upper side of the jack 31 through the hydraulic pipe 39 and the piston 32 is pushed down, so that the operation rod 25 is pushed down against the spring 28 via the ram 33 and the lower end of the lower end is pressed. As shown in FIG. 6, the contact portion 26 pushes the upper surfaces of the left and right enlarged excavation blades 20, 20 to close to the same width as the outer diameter of the spiral blade 18, and does not interfere with the lifting of the excavation rod 25.
[0023]
【The invention's effect】
As described above, according to the present invention, since the enlarged excavating blade is opened and closed by the operation rod provided through the excavating rod, the opening and closing of the enlarged excavating blade can be reliably performed to a desired enlarged diameter, In addition, since all of the opening / closing mechanism including the operation rod is built in the excavation rod, there is no malfunction due to clogging of earth and sand.
[Brief description of the drawings]
FIG. 1 is a schematic side view showing an example of an excavator to which the present invention is applied.
FIG. 2 is a front view, partly in section, showing one embodiment of the present invention.
FIG. 3 is a side view of the same.
FIG. 4 is a bottom view of the same.
5 is a cross-sectional view taken along the line AA in FIG.
FIG. 6 is an operation explanatory diagram showing a state during normal excavation.
FIG. 7 is an operation explanatory diagram showing a state during expanded excavation.
FIG. 8 is a cross-sectional view showing an example of a vertical movement operation mechanism of the operation rod.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 3 Leader mast 5 Drive part 10 Swivel apparatus 11 Excavation rod 13 Expansion head 14 Joint part 17 Support part 18 Spiral blade 20 Expansion excavation blade 21 Axis 23 Coil spring 24 Vertical movement operation mechanism 25 Operation rod 26 Contact part 31 Jack 32 Piston 33 Ram 39, 40 Hydraulic piping 42 Hydraulic pump 44 Chemical liquid outlet

Claims (1)

In an excavator in which a drilling rod is connected to a drive unit that can be moved up and down along a standing leader mast, and the drilling rod is rotated by the drive unit and the ground is excavated by a drilling head at the lower end thereof, the drive unit includes An operation rod supported so as to be vertically movable and provided through the excavation rod, and a pair of left and right enlarged excavation blades supported at the lower end of the excavation rod so as to be openable and closable. The support portion at the lower end of the excavation rod is pivotally attached to the support portion at the lower end of the excavation rod so as to be spread and pivoted in the vertical plane by the pivot, and the pivot and the blade portion of the enlargement excavation blade. The abutting portion of the lower end of the operating rod is in equal contact with both enlarged excavating blades on the upper surface between the tip and the left and right enlarged excavating blades are expanded when the operating rod is pulled up. Features Drilling enlarged head to.

Images