JPH07102870A - Screw rod joint section structure for underground boring machine - Google Patents

Abstract

PURPOSE:To appropriately position a packing which is interposed between a plug section and a socket section at the time of connection, prevent the pack ing from causing undesirable behaviors, and thereby reduce the occurrence of seal ruptures at the packing section to a great extent. CONSTITUTION:A packing 170 is formed with opening sections 172 and 174 corresponding to a plurality of fluid feed passages 45A and 46A, and concurrently, a circular projected section 177 projected to the thickness direction and a cylindrical member 178 with high stiffness are fixedly provide for the circumference of the opening section 174 corresponding to the fluid feed passage in which high pressure is built up, out of the opening sections, and for its inner circumferential surface respectively. The close incorporation of the aforesaid projected section and the cylindrical member into the fluid feed passages 45A and 46A permits the position of the packing 170 interposed between a plug section and a socket section at the time of connection to be determined, and since the circular projected section 177 is pressed on the circumferential wall, surface of the fluid passage with pressure its sealing performance is thereby enhnanced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joint portion structure of a screw rod for an underground drilling machine, which can be added depending on the depth of a drilling hole to be drilled, and a packing used therefor. .

[0002]

2. Description of the Related Art Conventionally, as an underground drilling machine, for example,
As can be seen in Japanese Patent Laid-Open No. 55-119885, the required number of screw rods having spiral blades on the outer circumference are sequentially connected to a power unit including a geared motor and a swivel device, and the There is known a structure in which an air hammer is connected to the lower stage, and an excavation hole is formed in the ground by lowering them while rotating them integrally along a leader mast.

As shown in FIG. 5, a screw rod used for such an underground drilling machine is generally provided with a spiral blade 52 on the outer periphery of a rod main body 51, and a male joint and a female joint at the upper and lower ends, respectively. A plug portion 54 forming a joint and a socket portion 55 into which the plug portion 54 is fitted are provided, and an air passage 45A made of a pipe 45a for supplying compressed air for driving an air hammer is vertically penetrated. And the socket portion 5 provided on the mating partner (screw rod 50) of the plug portion 54 or the socket portion 55.
5 or the plug portion 54, the packing 70 is inserted between the respective front end surfaces of the plug portion 5 and the plug portion 54 so as to be connected.

By the way, the applicant of the present application has proposed that, in an underground drilling machine equipped with a screw rod as described above, a soil reinforcement material such as cement milk is added from the vicinity of the tip of an air hammer connected to the lowermost stage of the screw rod. I have proposed a thing that is made to spout (Japanese Patent Application No. 5-
93145, etc.). This underground drilling machine
During drilling work or when pulling up the auger screw after drilling work, cement milks can be supplied or sprayed so as to form a wall on the inner or inner peripheral surface of the drilled hole, which can increase the formation strength. In addition to being able to prevent the drill hole from collapsing, it is possible to maintain the original shape of the drill hole and easily insert a pile or the like into the drill hole, and increase the frictional force around the pile or the like. Therefore, it is possible to minimize the amount of pile subsidence, which makes it possible to perform the construction quickly and easily, and to dramatically reduce the construction cost.

An example of the structure of the screw rod for that purpose and the joint portion between them will be described with reference to FIG. 6, in which the air supply passage 45A in the screw rod 50 including the plug portion 54 and the socket portion 55 is described.
Cement milks supply passages 46A, 46A composed of a pipe 46a and the like are formed on both sides of the above (this structure is shown in detail in FIG. 1 as described later). Further, through-holes 45b, 46b and 45c, 46c forming both ends of the cement milk supply passages 46A, 46A are also formed in the plug portion 54 'and the socket portion 55', and further arranged between the screw rods 50 '. Packing 7
In addition to the opening 72 for air, an opening 74 for cement milks is formed around 0 '. The positions of the openings 72, 74, 74 are set to the passages 45A, 46A, 46, respectively.
Connect the ends of the screw rods while positioning so that they match A.

However, each opening 72, 74, 7 formed in the packing 70 'disposed between the screw rods 50'.
Since it is difficult to position the position 4 in conformity with each passage 45A, 46A, 46A, the applicant has proposed and has already applied for an improved joint structure as shown in FIG. 7 ( (See Japanese Patent Application No. 5-159285).

A more practical example of the joint structure will be described with reference to FIGS. 6 and 7. As described above, the plug portion 54 'and the socket portion 55' have an air supply passage 45A and cement milk. Type supply passages 46A, 4
6A through holes 45b, 46b, and 4 forming both ends
5c and 46c are formed. The plug portion 54 ′ forming the male joint has a columnar fitting portion 54 a having a regular hexagonal cross-sectional outer shape, and a male male bottom portion having a larger diameter than that of the columnar fitting portion 54 a provided on the base side of the columnar fitting portion 54 a The anchor portion 54b, which has a larger diameter than the male type anchor portion 54b, has a main body 5
Socket part 55 'that forms the female joint with the tip of 1
A collar-shaped portion 54c having a circular cross-sectional outer shape that receives both of the tips of the
Also, an insertion portion 54 that is provided so as to project below the collar-shaped portion 54c and is inserted and attached to the distal end portion (upper end portion) of the rod main body portion 51.
In addition to d, a male upper anchor portion 54f having a smaller cross-sectional outer shape and having a smaller diameter than that is projectingly provided at the tip of the columnar fitting portion 54a.

Socket portion 5 forming a female joint
5'is a male lower bracing part 54b of the plug part 54 '.
, A cylindrical upper fitting part 55b into which the columnar fitting part 54a of the plug part 54 'is fitted, and a cylindrical fitting part 55a having a regular hexagonal cross section, and a larger diameter than this cylindrical fitting part 55a. A ring-shaped portion 55g, a male lower upper wax portion 54f into which the male upper wax portion 54f is fitted, and a packing 70 'described later, into which a packing having a diameter slightly larger than that of the cylindrical fitting portion 55a is inserted. Portion 55e, the plug portion 54 '
Has the same diameter as the collar portion 54c of the rod main body portion 51
Bottom wall 55c that receives the tip of the bottom wall, and this bottom wall 55c
In addition to the insertion portion 55d that is provided on the lower side of the rod main body portion 51 and is inserted into the tip portion (lower end portion) of the rod main body portion 51, the air supply passage 45A (45
a pair of cement milk supply passages 46A on both sides of c),
Recesses 55h and 55h having a pair of circular cross-sections into which the protrusions 76 and 76 (described later) of the packing 70 'are fitted are bored at intervals of 180 ° between the portions located between 46A (46c and 46c).

The packing 70 'is made of a rubber disc having elasticity and elasticity, and is approximately equivalent to the amount of extension when the rod is connected as compared with the packing insertion portion 55e of the socket portion 55'. As shown in the perspective view of FIG. 7, a circular air opening 72 having a diameter slightly larger than that of the air supply passage 45A is formed in the central portion, and the cement milks are provided on both sides thereof. Oval-shaped openings 74, 74 for cement milks larger than the supply passage 46A
And a pair of convex portions 76, 76 having a circular cross section and fitted in the concave portions 55h, 55h provided on the socket 55 'on one surface side are 180 °.
Projected at intervals.

In the structure of the screw rod joint having the above-described structure, the plug portion 54 'and the socket portion 55' are fitted together with the packing 70 interposed between the top and bottom surfaces thereof. The spring pins 56, 56 are inserted into and connected to the pin insertion portions 57, 57, 58, 58 provided at the left and right of the plug portion 54 'and the socket portion 55', respectively.

In this case, when the packing 70 'is arranged between the screw rods, the packing 7 is placed in the recesses 55h and 55h provided in the socket portion 55' of the screw rod.
The convex portions 76, 76 provided at 0 ′ are fitted. Thereby, the packing 70 'and the socket 55' are positioned, and the air opening 7 provided in the packing 70 'is positioned.
2 and the openings 74, 74 for cement milk and the air supply passage 45A (45c) provided in the socket 55 '.
And cement milk supply passages 46A, 46A (46
c, 46c).

Then, in the above state, the screw rod 5
Connect the mating screw rod 5 to the 0'socket part 55 '.
When the 0'plug portion 54 'is aligned and inserted, the air supply passage 45A (45c) on the socket portion 55 side is inserted.
And cement milk supply passages 46A, 46A (46
c, 46c) and the air supply passage 45 on the plug 54 'side
A (45b) and cement milk supply passages 46A, 4
6A (46b, 46b) communicates with each other through the packing 70 '.

[0013]

An underground drilling machine having the above-mentioned screw rod joint structure and an air hammer (see Japanese Patent Application No. 5-93145 for the basic structure of such underground drilling machine). The air is supplied from the air supply passage 45A (45a) to operate the air hammer, and the cement milks are supplied from the cement milk supply passages 46A and 46A (46b, 46b) to perform the drilling work. By doing so, the inner or inner peripheral surface of the drilled hole can be reinforced, the formation strength can be increased, and the drill hole can be made hard to collapse, and the construction can be done quickly and easily. It can be done, and the epoch-making effect that the construction cost can be drastically reduced can be obtained.

However, in the course of continuing many experiments, the cement milk supply passage 46A and the air supply passage 45A during the excavation work despite the packing 70 'interposed in the joint structure portion of the screw rod.
It has been experienced that there is a case where a seal break between the cement milk and the cement milk occurs and the cement milk may flow into the air supply passage 45A from the cement milk supply passage 46A.

This is due to the structure of the screw rod 50 'and its joint, and the axial distance H between the air supply passage 45A and the cement milk supply passage 46A (see FIG. 1,
(Refer to FIG. 3) has its own restrictions, and each passage 45
Since the diameters of A and 46A also require a predetermined size, the closest distance h between the air supply passage 45A and the cement milk supply passages 46A and 46A at the joint part must be relatively small. In addition, the pressure in the air supply passage fluctuates greatly due to the operation cycle of the air hammer, and the pressure in the cement milk supply passage becomes extremely high depending on the situation of the excavation site (maximum 20 to 30 kg / max.
It is understood that the cause is that it may reach about cm ² .

Since the inflow of cement milk into the air supply passage 45A hinders the operation of the air hammer, the occurrence of such itself must be prevented.
An object of the present invention is to eliminate the above-mentioned inconvenience of the joint part structure of the screw rod for the underground drilling machine, and more specifically, one fluid supply in the joint part structure of the screw rod for the underground drilling machine. It is to surely prevent the fluid from flowing from the passage to the other fluid passage.

[0017]

In order to achieve the above-mentioned object, the joint structure of the screw rod for an underground drilling machine according to the present invention is such that the packing has openings corresponding to the respective fluid supply passages. An annular protrusion protruding in the thickness direction is formed around the opening corresponding to the fluid supply passage in which at least a higher pressure is formed in the opening, and the inner peripheral surface of the annular protrusion is high. A rigid cylindrical member is fixed.

Of the fluid supply passage, at least the annular projection formed on the packing is located at the tip of the fluid supply passage, and the tubular member fixed to the annular projection and having a high rigidity. By forming the counterbore portion capable of accommodating the fluid, it is possible to reliably prevent the inflow of the fluid from the one fluid supply passage to the other fluid passage.

In a preferred embodiment of the present invention,
The packing is provided with a protrusion protruding in the thickness direction,
Further, the plug portion or the socket portion is provided with a concave portion into which the convex portion fits, and the packing can be positioned in the plug portion or the socket portion by fitting the convex portion into the concave portion. It will be done. The present invention further discloses a packing itself having a unique structure in order to achieve the above object.

[0020]

[Operation] In the joint structure of the screw rod for an underground drilling machine according to the present invention configured as described above, when connecting the screw rods, the screw rod is projected in the thickness direction formed around the opening of the packing. The packing and the plug portion or the socket portion are positioned by securely inserting the annular protruding portion and the cylindrical member having high rigidity into the fluid supply passage formed in the plug portion or the socket portion. The plurality of openings are aligned with the fluid supply passages of the plug or socket.

Then, in the above state, the socket part or the plug part of the coupling partner is inserted into the plug part or the socket part of the screw rod, and the plug part-socket part is fixed by a pin or the like, so that the packing is provided between the tip surfaces thereof. The screw rod is connected to the screw rod or the air hammer, the swivel device, or the like of the connection partner while being interposed.

Even when a very high pressure is formed in the cement milk supply passage during the excavation work as compared with the air supply passage, the pressure is formed around the opening of the packing. The annular protrusion protruding in the thickness direction and the cylindrical member having high rigidity act as a force for pressing the peripheral wall portion of the fluid supply passage formed in the plug portion or the socket portion, thereby further improving the sealing property.

Therefore, in the joint structure using the packing of the present invention, in addition to the advantage that the packing can be positioned easily and properly at all times, cement milks can be aired during excavation work. It is possible to reliably prevent a situation in which the air is mixed into the supply passage, and it is possible to reliably prevent a situation such as a malfunction of the air hammer from occurring.

Further, since the annular protruding portion of the packing is covered with the cylindrical member having a high rigidity such as a metal material, the packing is prevented from being damaged due to being exposed to the fluid side. Further forming a convex portion on the surface of the packing,
In the recess provided in the plug part or socket part of the screw rod or the socket part or plug part of the mating partner,
By fitting the convex portion, the packing and the plug portion or the socket portion can be positioned more reliably, and the plurality of openings provided in the packing and the fluid supply passage of the plug portion or the socket portion can be surely matched. Maintained.

[0025]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a partial sectional view of an embodiment showing a joint structure of a screw rod for an underground drilling machine according to the present invention. The shape of the packing used and the cement formed in the socket portion 55 ′ and the plug portion 54 ′ in a preferred embodiment. The joint structure is the same as that described above with reference to FIGS. 5 to 7, except for the shapes of the tip portions of the milk supply passages 46A and 46A. Therefore, the members corresponding to those shown in FIGS. 5 to 7 are designated by the same reference numerals, and detailed description thereof will be omitted.

First, the structure of the packing 170 used for the joint structure of the screw rod for an underground drilling machine according to the present invention will be described. As shown in FIG. 2, the packing 1
70, like the packing 70 ', is made of a rubber disc having elasticity and elasticity, and is equivalent to the amount of extension when the rod is connected as compared with the packing insertion part 55e of the socket 55'. The diameter of the air supply passage 45A is smaller than that of the air supply passage 45A, and a circular air opening 172 having substantially the same diameter as the air supply passage 45A is formed. Cement milk openings 174, 174 having the same diameter are formed on the one side, and further, on one surface side, there is a pair of circular cross sections to be fitted into the recesses 55h, 55h provided in the socket section 55 '. The convex portions 176 and 176 are projected at 180 ° intervals.

In the cement milk openings 174, 174 of the backing 170 of the present invention, annular projections 177, 177 are formed around the openings 174, 174 for projecting a predetermined length in the thickness direction, and the annular projections are formed. Parts 177, 1
A cylindrical member 1 made of a material having high rigidity such as a metal material such as an aluminum alloy or a hard synthetic resin material on the inner peripheral surface of 77.
78 is fixed by an appropriate means such as baking or an adhesive.

Further, as shown in FIGS. 1 and 3, in this embodiment, a cement milk supply passage 46A formed in the socket portion 55 'of the screw rod 50',
46A and the cement milk supply passages 46A and 46A formed on the side of the plug portion 54 'respectively have packing 170
A counterbore portion 146A having a size capable of accommodating the annular protruding portion 177 and the cylindrical member 178 fixedly mounted on the inner peripheral surface of the annular protruding portion is engraved at a tip end portion on the side opposite to.

Also in the joint structure of the screw rod for the underground drilling machine according to the present invention, the packing 17 described above is used.
0 is mounted in a state where it is easily positioned between the tip surfaces of the socket portion 55 'and the plug portion 54' in the same manner as in the case of the prior example, and the screw rod and the screw rod of the mating partner or the air hammer, swivel device, etc. Are connected. At that time, the annular protruding portion 177 formed on the packing 170 and the tubular member 1 fixed to the inner peripheral surface of the annular protruding portion 177.
Reference numeral 78 denotes the cement milk supply passage 4 formed in the socket portion 55 'and the plug portion 54' as shown in FIG.
The counterbore portion 146 engraved in each of 6A and 46A.
It is housed in A.

Therefore, in the joint structure according to the present invention, the cement milk supply passage 46 is provided during excavation work.
Even when a very high pressure is formed in A and 46A as compared with the air supply passage 45A, the pressure is formed in the opening 174 of the packing 170 and protrudes in the thickness direction. And a cylindrical member 178 having a high rigidity fixed thereto and a peripheral wall portion of the cement milk supply passage 46A formed in the plug portion or the socket portion (in the illustrated embodiment, a peripheral wall portion of the counterbore portion 146A).
It acts as a force for crimping to, and rather the sealability is further improved. Therefore, it is almost certain that the cement milks are prevented from flowing into the air supply passage 45A due to the breakage of the seal, and the operation of the air hammer or the like is prevented from being hindered.

Further, since the annular protruding portion of the packing is covered with the cylindrical member 178 having a high rigidity such as a metal material, the packing is prevented from being damaged by being exposed to the fluid side such as cement milk. . In the above description, the connection between the screw rods 50 'has been described as an example, but the connection between the screw rod 50' and another member, such as a swivel device or an air hammer, is similar to the plug portion 54 'described above. Alternatively, it goes without saying that the packing 170 can be applied by providing the socket portion 55 ′.

Further, in the above example, the recessed portions 55h, 55h are provided in the socket portion 55 ', but the recessed portions may be provided in the plug portion 54', and in that case, the same effect can be obtained. In addition, in the above-described embodiment, the recesses 55h and 55 provided in the socket portion 55 'are provided on one surface side of the packing.
a convex portion 176 having a pair of circular cross sections fitted in h,
Although the 176 has been described as protruding at 180 ° intervals, the annular protruding portion 177 formed in the opening of the packing and the cylindrical member 178 fixed to the annular protruding portion 177 are formed in the plug portion or the socket portion. If the packing can be positioned with respect to the plug portion or the socket portion by entering the peripheral wall portion of the cement milk supply passage 46A, the convex portions 176 and 176 are not necessarily essential and the initial purpose is not required. Is achievable. In that case, of course, it is not necessary to form the recesses 55h and 55h provided in the socket 55 '.

In the above embodiment, the annular protrusion 177 is used.
Also, the cylindrical member 178 having a high rigidity fixed thereto is provided only around the cement milk openings 174, 174, but as shown in FIG. 4, the opening 172 of the air supply passage side is formed. Similarly, the annular protrusion 1 also surrounds
72A and a cylindrical member 172B having a high rigidity may be formed, whereby the stability of the operation can be further improved (the one shown in FIG. 4 is a convex portion having a circular cross section for the reason described above. No equivalent of 176, 176 has been formed).

Further, the cement milk supply passages 46A, 46A and the plug portion 5 formed in the socket portion 55 '.
Cement milk supply passage 46A formed on the 4'side,
The counterbore portions 146A formed on the tip end portions of the respective 46A facing the packing 170 are provided for the purpose of smoothing the flow of the fluid flowing in the supply passage by accommodating the annular protrusions therein. However, it will be easily understood that the provision of the counterbore is not essential.

Further, in the above embodiment, the arrangement of the fluid supply passage has been described as the one in which the air supply passage 45A is provided in the central portion of the screw rod 50 and the cement milk supply passages 46A, 46A are formed on both sides thereof. But,
This arrangement is not limited to this, but the screw rod 5
One cement milk supply passage 4 in the center of 0
6A is provided, and air supply passages 45A, 45 are provided on both sides thereof.
A may be formed, and each opening may be formed in the packing correspondingly.

[0036]

As can be understood from the above description, according to the joint structure of the present invention, in addition to the effect that the packing can be positioned easily and properly,
Even if there is a large pressure fluctuation during excavation work, it is possible to eliminate the occurrence of seal breakage as much as possible, and it is possible to reliably prevent cement milk from mixing into the air supply passage. Therefore, it is possible to prevent the excavation work from being interrupted due to malfunction of the air hammer.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a joint structure of a screw rod for an underground drilling machine according to the present invention.

FIG. 2 is a plan view (A) and a sectional view (B) showing an embodiment of a packing used in the present invention.

FIG. 3 is an exploded perspective view showing a plug portion, a packing, and a socket portion in the joint portion structure.

FIG. 4 is a plan view (A) and a sectional view (B) showing another embodiment of the packing used in the present invention.

FIG. 5 is a side view of the screw rod used for explaining the joint structure.

FIG. 6 is a cross-sectional view mainly used for explaining a conventional joint structure.

7 is an exploded perspective view showing a plug portion, a packing, and a socket portion in the joint portion structure shown in FIG.

[Explanation of symbols]

 50'-screw rod 54'-plug part 55'-socket part 170-packing 172-air opening 174-cement milk opening 177-annular protrusion 178-fixed to the inner peripheral surface of the annular protrusion. Cylindrical member 146A-counterbore part

Claims (7)

[Claims] 1. A spiral blade is provided on the outer circumference,
The upper and lower end portions are provided with plug portions that respectively form a male joint and a female joint and a socket portion into which the plug portions are fitted, and a plurality of fluid supply passages are provided in the interior so as to extend vertically. It is a joint structure of a screw rod for an underground drilling machine that is connected by inserting the plug part or the socket part into the socket part or the plug part provided on the mating partner with the packing interposed between the respective tip surfaces. An opening corresponding to each of the fluid supply passages is formed in the packing, and a thickness direction is provided around the opening corresponding to the fluid supply passage in which at least a higher pressure is formed in the opening. Underground drilling machine, which is formed with an annular projecting portion projecting to the inside and a cylindrical member having high rigidity is fixedly provided on the inner peripheral surface of the annular projecting portion. Screw rod joint structure. 2. The packing according to claim 1, further comprising a convex portion protruding in the thickness direction, and the plug portion or the socket portion having a concave portion into which the convex portion is fitted. Joint structure of screw rod for underground drilling machine. 3. A screw rod is provided with an air supply passage extending vertically through the center of the screw rod, and cement milk supply passages are provided longitudinally on the left and right sides of the air supply passage. An opening corresponding to the supply passage and the cement milk supply passage is formed, and an annular protrusion protruding in the thickness direction is formed at least around the opening corresponding to the cement milk supply passage. The joint part structure of the screw rod for an underground drilling machine according to claim 1 or 2, wherein a cylindrical member having high rigidity is fixedly provided on an inner peripheral surface of the annular protrusion. 4. A screw rod is provided with a cement milk supply passage extending vertically through the center of the screw rod, and air supply passages are provided on the left and right sides of the air supply passage so as to extend vertically. An opening corresponding to the supply passage and the cement milk supply passage is formed, and an annular protrusion protruding in the thickness direction is formed at least around the opening corresponding to the cement milk supply passage. A cylindrical member having high rigidity is fixedly provided on the inner peripheral surface of the annular protrusion.
Or the joint part structure of the screw rod for the underground drilling machine according to 2. 5. The annular protrusion and a high rigidity fixed to the annular protrusion are provided at a tip portion of the fluid supply passage in which at least the annular protrusion formed in the packing is located in the fluid supply passage. The joint part structure for a screw rod for an underground drilling machine according to claim 1, wherein a counterbore part capable of accommodating the holding cylindrical member is formed. 6. A plurality of fluid passage openings are formed, and an annular protrusion protruding in the thickness direction is formed around the openings, and the inner peripheral surface of the annular protrusion is high. Packing used for joint part of screw rod for underground drilling machine, which is made of rigid cylindrical members. 7. The packing used for the joint portion of the screw rod for an underground drilling machine according to claim 6, further comprising a convex portion projecting in the thickness direction on the surface.