JPH079148B2 - Tricombit in Underground Drilling Rig - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to an excavation tricone bit, and more particularly to a tricone bit in an underground excavation device.

(Prior Art) Conventionally, when burying a steel pipe or the like in the ground, an underground drilling device has been used, in which a pipe is buried while drilling a lateral hole in the ground.

In this case, if the ground in which the pipe is buried is in a stratum containing gravel, etc., a tricone bit is annularly arranged at the tip of the excavator, and the tricone is driven by the revolution of the tricone bit to drive the gravel. Even strata can be crushed and excavated.

(Problems to be solved by the invention) However, in the conventional drilling device using the triconbit,
Inside the tip of the front conduit of the casing provided inside the buried pipe, a plurality of outer tricon bits whose axial center is directed toward the center of the forward position of the front conduit and a plurality of inner tricon whose axial center is directed outward. The bits are arranged annularly.

With such a structure, since the conical surface of the outer tricon bit is not parallel to the conical surface of the inner tricon bit, the tip side of the outer tricon bit and the base side of the inner tricon bit are the same. It is more likely that lumps of pebbles will come into contact. In such a case, the tip side blades are always in contact with each other at the same location and excavated, so that the blades are heavily worn, and even if the base side blades are not so worn, the number of times of replacement for wear is frequent.

As a measure against such a problem, the apex of the cone forming the outer tricon bit is made to coincide with the bore axis of the leading conduit, and the bit length is the same as before, that is, the tip side is not a point but a surface. Although we devised one with a gentle cone angle, this solves the problem of one-sided slippage, but there is a new problem such as excavation resistance increases due to the increase in the surface area of the bit, and it cannot rotate effectively. occured.

In view of this, the present invention has been made in order to solve the drawbacks of the prior art by providing a tricone bit in an underground excavation device which prevents slippage and smoothes rotation.

[Structure of Invention]

(Means for Solving the Problems) In order to achieve the above object, in the present invention, a plurality of triconbits having an axial center toward the center of the forward position of the front conduit of the casing inserted in the buried pipe are annularly formed. In the underground excavator arranged in, the tricon bit having a substantially conical shape is separated in the direction orthogonal to the axis of the excavator and divided into two parts, a large bit at the base and a small bit at the tip. Is formed in a shape that substantially coincides with the center of the forward position of the leading conduit, and a tricone bit in an underground excavating device in which a supporting member is interposed between a large bit and a small bit and rotatably supported is provided. Characterize.

[Work]

By adopting such a configuration, it is possible to reduce abnormal wear of only the local portion when the tricone bit rotates, and to prevent the tricone bit from rotating at the same time when the excavation resistance is large by dividing the tricone bit into a large bit and a small bit. Is done smoothly.

〔Example〕

The present invention will be described below with reference to the embodiments shown in FIGS. 1 to 6.

A hollow underground excavator to which the present invention is applied has a buried pipe 3 placed in a base 2 installed in a solid hole 1 and a front conduit in the front thereof as shown in the cross section of FIG. A casing 4 in which 5 is arranged is rotatably supported in the embedded pipe 3 by a plurality of rollers 6 and is slidable in the front-rear direction.

The drive source for excavating the buried pipe 3 and the casing 4 transmits power from the geared motor 7 to the propulsion jack 8 via a chain or the like (not shown), and the operation of the propulsion jack 8 enables lateral excavation. ing.

On the front surface of the buried pipe 3, there is a cutting edge 9 provided around the tip conduit 5, and in the tip conduit 5 a plurality of supporting members 10 are provided.
One end is rotatably attached, and the other end is provided with an outer bit 11.

In FIG. 1, the inner bid actually provided is omitted because it is a schematic view.

The earth and sand excavated by the cutting edge 9, the outer bit 11 and the inner bit (not shown in FIG. 1) are discharged from the tip conduit 5 through the casing 4 and a discharge port (not shown).

In the figure, reference numeral 12 is a running hose, 13 is a main power cap tire cord, and 14 is a running hydraulic hose.

As shown in FIGS. 2 and 3, the tricon bit 15 of the underground excavation device according to the present invention includes a large base bit 16, a small tip bit 17, and a supporting member 18 provided therebetween. The shaft 19, which extends over the three members, and the bearings 20, 20 provided on the large base bit 16 and the small tip bit 17 are included.

The base large bit 16 and the small tip bit 17 are formed in a form in which an integral tricone bit having a substantially conical shape is divided in a direction orthogonal to the axis 21 thereof. 17 conical busbars 22,2
The apex of 2 is formed in a shape that substantially coincides with the center O (shown in FIG. 4) at the front position of the front conduit 5.

The base large bit 16 and the small tip bit 17 have a conical shape in which a projection 25 such as a blade is implanted in the conical main bodies 23 and 24, and the large base bit 16 and the small tip bit 17 are formed. The support portion 26 of the support member 18 is provided between them.

A shaft 19 is fixedly mounted on the support portion 26, and the large base bit 16 and the small tip bit 17 are rotatably supported at both ends of the shaft 19 via bearings 20 and 20, respectively.

FIGS. 4 to 6 show an embodiment of an underground excavation device to which the triconbit according to the present invention is applied. The same parts as those shown in FIG. Inside the pipe 4 inserted into the pipe 3, the inside of the front conduit 5 of the casing 4, a plurality (four in the figure) of the outer tricone bit 15 of the present invention whose axial center is directed to the front center of the front conduit 5. , 1
5, ... and a plurality (4 in the figure) of inner trikon bits located between each of the outer trikon bits 15, 15 ...
27, 27 ... And are arranged in a ring.

The outer tricon bit 15 is provided with the support member 18, and the support member 18 has first and second annular members 28 fixed to the inner circumference of the leading conduit tube 5 at predetermined intervals in the front and rear direction. 2
Among the nine, a front first annular member 28 is provided with a stopper portion 30 and a push-back means 31, and a second annular member 29 is provided with a bearing portion 32, respectively.

The support member 18 extends from the support portion 26 to about 35 in the illustrated embodiment.
A twisted portion 33 that is inclined by a degree is formed, and a flat portion 34 is further formed from the end of the twisted portion 33.

Therefore, the surface of the support portion 26 and the surface of the flat portion 34 are formed at an angle twisted by the twisted portion 33.

One side surface 35 of the flat portion 34 can come into contact with the stopper portion 30, and an end portion 36 of the flat portion 34 is engaged with the bearing portion 32.

The first annular member 28 is provided with an angular guide hole 37 in an inclined state from the vicinity of the outer circumference to the vicinity of the circumference. The guide hole 37 extends in the width direction when the flat portion 34 of the support member 18 is inserted. It can be fitted loosely, and one end portion in the width direction thereof is formed in the stopper portion 30.

Further, the first annular member 28 has a push-back means 31 (spring in the fifth illustration) such as a spring, a damper, or an elastic body similar to this.
Is provided so that it is always pressed against the other side of the support member 18.

The second annular member 29 is provided with a bearing portion 32 that engages with the end portion 36 of the flat portion 34 at a bifurcated portion.

In this case, the hole 38 at the end 36 of the flat portion 34 of the support member 18 is
The bearing member 32 of the annular member 29 is pivotally supported by the pin 39,
This allows the support member 18 to swing around the pin 39.

When the one side surface 35 comes into contact with the stopper portion 30 by pressing the other side of the flat portion 34 by the push-back means 31,
Base large bit 16 forming outer tricon bit 15
And the tip small bit 17 is rotated to project to the outside of the outer diameter of the buried pipe 5 and come to the position of the excavated state.

In FIG. 5, a plurality of cutting edges 9 are provided on the outer periphery of the front conduit 5 and are set in a protruding state by bolts 40 when excavating. 40 can be approached to the outer peripheral surface so that it can be folded and folded. Reference numeral 41 in the figure is a joint flange.

Next, the operation will be described.

First, before starting excavation, the outer tricon bit 15 according to the present invention is projected from the outer diameter of the buried pipe 3, that is, one side surface 35 of the support member 18 is brought into contact with the stopper portion 30, When the casing 4 is rotated clockwise, for example, by a drive device (not shown), the front conduit 5 is integrally rotated, and the outer and inner triconbits 15 and 27 are revolved. The revolution of these tricone bit 15,27 crushes the gravel in the ground,
The crushed gravel is taken into the casing 4, conveyed backward by a spiral blade (not shown), and discharged to the ground.

The outer and inner tricon bits 15 and 27 contacting the gravel rotate about the centers of the shafts between the support portion 18 and the support portions (not shown), respectively. Especially, in the outer tricon bit 15, the large base bit 16 and the small tip bit are provided. Rotate independently of 17 and rotate slowly if the resistance is high and fast if the resistance is low and crush the gravel while keeping the tip contact with the gravel instead of point contact with the gravel.

In this case, the outer tricone bit 15 is pressed by earth pressure in a forward rotation (for example, right rotation) in a direction protruding to the outside of the buried pipe 5, and in reverse rotation (for example, left rotation) by the earth pressure. Pressure is applied in the direction in which the diameter decreases. Then, when the earth pressure disappears, the supporting member 18 is pressed by the pushing-back means 31 to enable an early return to the excavation posture.

Therefore, when the outer tricon bit 15 is replaced due to wear or the like, the front conduit 5 is retracted, and when the rear end of the buried pipe 3 is reached, the pin 39 is removed from the bearing portion 32 to which the support member 18 is coupled. It may be pulled out from the guide hole 37 of the first annular member 28. And to install a new Trikon Bit 15 or a repaired Trikon Bit 15, reverse this procedure.

It should be noted that in the embodiment, the case where the support member has a twisted portion has a twist angle of 35 ° has been described, but the twisted portion is not essential, and in some cases it is not necessarily limited to 35 °.

(Effects of the Invention) As described above, the present invention provides underground excavation in which a plurality of tricone bits are disposed in an annular shape, the axis of which is oriented toward the center of the forward position of the front conduit of the casing inserted into the buried pipe. In the machine, a tricone bit having a substantially conical shape is separated in a direction orthogonal to its axis to divide it into a large base bit and a small bit at its tip, and the vertices of the generatrix of these large and small bits are divided into two parts. Since it is formed in a shape that substantially coincides with the center of the front position and is rotatably supported by interposing a supporting member for supporting the casing between the large and small bits, the tip small bit also has only the cutting edge of the conical apex. The conventional problem of abnormal wear due to contact with gravel is eliminated, local wear is eliminated because the protrusion of the entire conical surface contacts the gravel, and the problem that effective rotation cannot occur due to contact with the protrusion of the entire conical surface Against In the present invention, since the tricone bit is divided into two, that is, the large base bit and the small tip bit, both bits can rotate independently of each other, which reduces wear of the blade of the tricone bit. , Excavation efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a side view showing an outline of an underground excavator to which the present invention is applied, FIG. 2 is a front view of an embodiment of a tricone bit according to the present invention, and FIG. 3 is a side view of FIG. , Fig. 4 is a front view of the underground excavation equipment to which the triconbit of the main body is applied, and Fig. 5
FIG. 6 is a side view of FIG. 4, and FIG. 6 is a perspective view of an embodiment showing the relationship between the tricone bit and the supporting member of the present invention. 3 ... Buried pipe, 4 ... Casing, 5 ... Front conduit, 15 ...
… Tricon bit, 16 …… Base large bit, 17 …… Small tip bit, 18 …… Supporting member, 19 …… Shaft, 20 …… Bearing, 21…
… Axis, 22 …… Bus, O …… Center of front conduit.

Claims (1)

[Claims] 1. An underground excavator in which a plurality of triconbits, each of which has an axis directed toward the center of the front position of a front conduit of a casing inserted into a buried pipe, are annularly arranged and have a substantially conical shape. The tricone bit is separated in a direction orthogonal to its axis and divided into two, a large base bit and a small tip bit,
The vertices of the generatrix of the large and small bits are formed to have a shape that substantially coincides with the center of the front position of the leading conduit, and a supporting member for supporting the casing is interposed between the large and small bits so as to be rotatable. Triconbit in an underground drilling rig characterized by being pivotally supported.