JP2941194B2 - Rod exchange device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rod exchanging device for supplying a rod to a drilling machine, and removing and recovering the rod.
More particularly, the present invention relates to a rod exchanging device provided with a rod magazine arranged along a guide cell and accommodating a plurality of rods.

[0002]

2. Description of the Related Art In an anchoring work or a pouring work, a single pipe rod or a double pipe rod having a predetermined length is successively added and drilled to a predetermined depth. Conventionally, rod supply /
The entire collection process was performed manually,
In recent years, in order to improve work efficiency and safety, a rod exchange device in which supply, removal, and recovery of the rod is mechanized has been developed and put to practical use.

Various types of rod exchange devices have been proposed, one example of which will be outlined with reference to FIG. The rod exchanging device 1 shown in FIG. 1 is disposed along a side of a guide cell 50 supported by a drilling machine, and is disposed below a rod magazine 2 for accommodating a plurality of rods. And a rod clamp device 3. The rod magazine 2 accommodates a plurality of rods along the same circumferential line when viewed in a horizontal cross section, and the support arms 20, 21 of the rod magazine 2 rotate about a vertical axis. . In the refilling step, the rod magazine 2 is rotated to align one rod in the rod magazine 2 on the perforation line O of the drifter 51 as shown in FIG. When the rod magazine 2 is connected to the rod, the rod magazine 2 is retracted, and the drifter 5 is attached to the upper end of the penetrated rod.
After the lower end of the rod suspended by 1 is screwed and connected, the rod is advanced while rotating the rotating shafts 60 and 61 of the drifter 51 to penetrate the ground.

[0004] The rod clamp device 3 provided at the lower portion of the rod magazine is used to connect the drifter 51 to one rod housed in the rod magazine 2 in a rod extension step or in the recovery step. When the drifter is separated from the rod collected inside, the rod is clamped so as not to rotate.

Another rod exchange device provided with a rod magazine is disclosed, for example, in Japanese Patent Application Laid-Open No. 61-212492.
JP, JP-A-63-93988, JP-A-5-1
No. 9637, and the like.

[0006]

However, in the case of the rod exchanging device which has been conventionally proposed, when the screw portion of the rotating shaft on the drifter side is screwed and connected with the screw portion of the extending rod, the extension rod and In many cases, the thread of the rotating shaft is crushed or the support member of the rod magazine or the clamp device is damaged. Specifically,
When advancing the drifter to one of the rods housed in the rod magazine for screw connection, it is very difficult to completely match the advancement length of the drifter with the screwing length of the screw due to the operability of the drifter. It is difficult, and the amount of forward movement of the drifter is often longer than the screwing length of the rotary shaft side screw portion and the extended rod side screw portion. In this case, the driving force of the drifter directly acts on the screwing screw portion, the rod support portion of the rod magazine, the clamp device, etc., thereby crushing the thread of the extended rod or the rotating shaft, or supporting the rod magazine or the clamp device. The member may be damaged. Also, when collecting the rod, the same problem as in the case of connection occurs when the collecting rod side thread is cut off from the rotary shaft thread of the drifter.

On the other hand, as a matter of course, the operation of the drifter should be carefully performed so that the advance or retreat length of the drifter can be made to match the screwing length or the cutting length of the screw portion as completely as possible so as not to cause the above-mentioned problem. Operation. Therefore, it takes a lot of time to connect or disconnect the rotary shaft and the rod, which has caused a reduction in work efficiency.

[0008] Therefore, a main object of the present invention is to make it possible to absorb and mitigate even if a drifter propulsion force acts when connecting / disconnecting a rod housed in a magazine and a rotary shaft of a drifter. It is an object of the present invention to provide a rod exchanging device which does not crush a screw thread of a rotary shaft or a rotary shaft, and does not damage a support member of a rod magazine or a clamp device.

[0009]

According to the present invention, there is provided a rod exchanging apparatus for supplying a rod to a drilling machine or recovering a rod from the drilling machine. A rod magazine is provided along the guide cell of the drilling machine, has a rod storage section for storing the rod at an appropriate position on the outer peripheral portion, and has a rod magazine for supplying the rod on the guide cell or collecting the rod from the guide cell. The accommodated rod is elastically supported in a state where it can be moved directly or indirectly in the longitudinal direction of the rod by interposing the buffer means on the rod receiving portion of the rod magazine or the supporting member of the rod magazine. It is characterized by the following.

Further, the rod exchanging device includes a rod clamp device for fixedly holding a predetermined rod in the rod magazine, and the clamp device is movable in the longitudinal direction of the rod through a buffer means. It is characterized by being elastically supported in the state.

As the buffering means, a spring member or a damper structure can be preferably used.

In particular, when a double pipe rod is intended, the rod magazine is provided with an outer pipe rod receiving section and an inner pipe receiving section at the lower end of each of the accommodated rods, and these are provided with buffer means. By providing the inner tube and the outer tube, both the inner tube and the outer tube are elastically supported in the longitudinal direction of the rod, and the clamp device fixedly grips the outer tube with the outer tube clamp device that fixedly grips the outer tube. And an inner tube clamping device, both of which are elastically supported in a state of being movable in the longitudinal direction of the rod by interposing the buffer means.

Further, a load detecting means for detecting a load acting on the rod magazine when connecting / disconnecting the drifter can be attached.

[0014]

According to the present invention, the rod accommodated in the rod magazine is elastically supported in a state in which it can move in the longitudinal direction of the rod. In the case where the clamp device is configured to hold the rod in a fixed manner, that is, in a structure in which the rod is fixedly held so as not to move in the longitudinal axis direction, the clamp device is also moved in the longitudinal direction of the rod by similarly interposing a buffer. Elastically supported in a movable state. Therefore, when connecting / disconnecting the drifter and the rod, even if the advancement length or the retreat length of the drifter is too long than the screwing length or the separation length of the screw portion and the rod receives the propulsive force of the drifter, the rod is still connected to the spring. Since the rod moves by the contracting action of the buffer means, and the rod moves by the excess movement amount of the drifter, it is not necessary to crush the screw thread or to damage the rod magazine or the support member of the clamp device.

[0015] Even if the advancement length and the retreat length of the drifter are longer than the screw length and the separation length of the screw portion, the safety of the connection and disconnection work is ensured and the operation of the drifter becomes easy. The rod replacement work can be performed quickly.

When the rod magazine is mounted on the guide cell via a support member, a load detecting means such as a load cell is provided to detect a load acting on the rod magazine when connecting / disconnecting the drifter. It can be clearly determined whether or not the screw portion on the side and the screw on the drifter side are screwed or separated successfully. In other words, when screwing or disconnection is not successful, the feed force or pulling force of the drifter is applied to the load cell, and the load detected by the load cell rises rapidly. You can easily check the screwed or disconnected state.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on embodiments.
FIG. 1 is a side view of a state in which a rod exchanging device is attached to a drilling machine. In the drilling machine, a punching device S is attached to a base machine M having a crawler traveling unit so that the drilling machine can move freely. The punching device S is mainly composed of a mast-shaped guide cell 50 and a drifter 51 mounted on the guide cell 50 and movable in the longitudinal direction.
The inclination angle, that is, the perforation angle of the guide cell 50 can be adjusted to some extent by cylinders 62 and 63 provided in a connecting member portion with the base machine M.

At the distal end of the guide cell 50, from the distal end side, in order from the distal end side, an outer pipe centrizer 52 with a clamping function, an outer pipe threading device 53, an inner pipe centrizer 54 with a clamping function, and an inner pipe threading. A device 55 is provided. The St. riser 5 2, 5 4, at the time of boring functions as centering device to align the rod axis to the drilling center line, at the time of build-up and recovery of the rod serves as a clamping device. The threaded device 5 3,
5 5, FIG. 10 (A), as shown (B), the pair of chuck pieces 52A for clamping the rod R (54A), 5
The cylinder 52B (54B) that rotates the rod R by rotating the chuck device 2A (54A) and the entire chuck device.
It is mainly used when removing and collecting the rod.

In the drifter 51, a rotary drive device 57 for the outer tube and a rotary drive device 58 for the inner tube are mounted on a propulsion table 56, and the rotary drive device 58 for the inner tube is
By means of 9, a predetermined amount can be moved on the propulsion base 56 along the longitudinal direction of the guide cell. Further, protruding from the distal end of the outer tube shaft 6 0 passes through the inside of the outer tube shaft 6 0 of the inner tube shaft 61 for the inner pipe rotary drive 58 is the outer tube rotating drive device 57.

A rod exchanging device 1 according to the present invention is provided on a side portion of the guide cell 50. Hereinafter, the rod exchanging device 1 will be described in detail with reference to FIGS. 2 to 9. FIG. 2 is a front view of the rod magazine 2, FIG. 3 is an enlarged side view of a rod receiving portion of the rod magazine, and FIG. FIG. 5 is a front view, FIG. 5 is a view taken along line VV of FIG. 2, and FIG.
FIG. 6 is a view taken along line VI-VI of FIG. The rod exchanging device 1 includes a rod magazine 2 disposed along a side of a guide cell 50 supported by a drilling machine and accommodating a plurality of rods, and a rod clamp device 3 disposed below the rod magazine 2. It is composed of The rod magazine 2 includes an upper magazine support member 20 provided on the upper side of the guide cell 50 so as to be rotatable around a vertical axis around a shaft 20a,
A lower magazine support member 2 provided on the lower side of the guide cell 50 so as to be rotatable around a vertical axis around the shaft 21a.
And a magazine rack 22 for accommodating a plurality of rods R, R,. This magazine rack 22 is coaxially fixed to a rack center shaft member 24 provided over the magazine upper support member 20 and the magazine lower support member 21 and to a lower end side of the rack center shaft member 24. Each of the rods R, R,... Is accommodated in a rod accommodating portion formed at an appropriate position on the outer periphery, as shown in FIGS. More specifically, on the upper surface side of the rod support plate 23, the inner tube support pins 2 for supporting the inner tube at appropriate intervals along the same circumferential line.
3a, 23a... Are erected, and an outer pipe receiving member 26 for supporting the outer pipe in a receiving state is provided slightly above the inner pipe support pins 23a, 23a. The lower ends of the rods R are supported by the inner pipe support pins 23a, 23a... And the outer pipe receiving member 26, and the rods are erected by rod guide members 31, 32 provided at intermediate positions in the longitudinal direction. Held in state.

The rod guide members 31 and 32 are supported by a connecting pipe 11 provided across the upper magazine support member 20 and the lower magazine support member 21, and have the same circumference as shown in FIG. The rod housing recess 31a (3
2a) to accommodate each rod R, R... In a predetermined position. Also, when supplying and collecting the rod, the cylinder 34 is used.
A part of the peripheral frame (open / close frame piece 33) is controlled to open and close by the
A predetermined rod can be taken out of the magazine rack 22 or housed in the magazine rack 22.

The entire rod magazine 2 is rotatable around shafts 20 a and 21 a by a cylinder 10 provided on the side of the lower magazine support member 21, and the lifter 51 moves on a guide cell 50. One position accommodated in the rod magazine 2 at a position where a predetermined rod accommodated in the magazine rack 22 can be connected to the rotating shaft, that is, a perforation axis O coinciding with the shaft axis of the drifter 51 shown in FIG. Movement control is performed between a rotation position where the rod is matched and a rotation position retracted from the position.

Further, the lower surface side of the magazine under the support 21, L-shaped accession Chue over data support base 30 is vertically provided, the accession Chue over data placed on the support table 30 a hydraulic Accession whole Chue over the by motor 29 magazine 22 is adapted to be rotated as the rotation shaft of the rack central shaft member 24, sequentially rod R to the perforation on the axis O
Can be supplied.

[0024] In the first embodiment of the present invention, the inner tube supporting pins 23a, outer tube R _o rod longitudinally supported within tube R _i and the outer tube for receiving material 26 is supported 23a ... It is elastically supported in a movable state. 3, the detail based on FIG. 4, each inner tube supporting pins 23a, 23a ... and the spring 27 is provided in the fitted state, the lower edge of the tube R _i to be inserted on the spring 27 By being placed, the inner tube _Ri is elastically supported so as to be movable in the longitudinal direction of the rod.
The outer tube receiving member 26 has a hole through which the outer tube _Ro is inserted via a connecting member 26b into a ring-shaped member 26a which is fitted to the rack center shaft member 24 so as to be movable. tube receiving cylinder 26c is fixed, threaded stepped portion of the outer tube R _o is supported in a state receiving the outer tube R _o by engaging the edge of the hole. The connecting member is in the 26 b lower surface of the provided or spring 28, 28 number between the rod support plate 23, and supports the entire outer pipe supporting member 26 elastically. Thus, the outer tube R _o to be supported are elastically supported movably in the rod longitudinal axis direction by receiving member 26 for the outer tube.

On the other hand, when the rod is supplied or the rod is collected, the drifter 51 is attached to the tip of the lower magazine support member 21.
When connecting and disconnecting the rod R
There is provided a clamp device 3 for fixing the rotator so as not to rotate. The clamp device 3 includes the lower support member 2 for the magazine.
1 and a clamp support bracket 41 via a shaft 40
Are provided so as to be rotatable around a vertical axis, and a clamp support member 42 erected on the clamp support bracket 41 is provided with an outer tube clamp 4 and an inner tube clamp 5 from the distal end side. As shown in FIG. 4, the outer tube clamp 4 and the inner tube clamp 5 are slide outer tubes that are movable in the longitudinal direction and externally fitted to the distal-side narrow portion 42 a of the clamp support member 42. It is fixed to the member 44 and is elastically supported by a spring 43 provided inside the lower end of the slide outer tube member 44 so as to be movable in the longitudinal direction of the rod.

As shown in detail in FIG. 7, the outer tube clamp 4 and the inner tube clamp 5 are swingably provided by a clamp arm 45 and a shaft 46a which are swingably provided by a shaft 45a. A clamp arm 46 is provided symmetrically, and rear ends of the clamp arms 45 and 46 are connected by a cylinder 47. Therefore, the distal ends of the clamp arms 45 and 46 are opened and closed by the expansion and contraction operation of the cylinder 47 so that the outer tube or the inner tube can be gripped.

The clamp device 3 is rotatable about an axis 40 by a cylinder 49 connecting the lower magazine support member 21 and the lower end of the clamp support member 42. As shown in FIG. Movement control is performed between a rotation position at which a predetermined rod accommodated in 22 can be clamped and a rotation position retracted from the position.

In this embodiment, the chuck of the rod R by the clamp arms 45 and 46 is fixed,
That is, since the chuck is performed so that the rod R cannot move in the axial direction and does not rotate, the clamp device 3 can be moved so as to follow the movement of the rod R as described above. If, for example, a roller follower is provided at the tip end of the chuck to allow the gripped rod R to move in the longitudinal direction, but not to rotate, the clamp device 3 does not need to be elastically supported.

Instead of the rod elastic support mode described in detail above, the rod R can be elastically supported by a support mode shown in FIG. The support mode shown in FIG.
A magazine support slide 14 is provided via a spring 13 on a fixed support 15 fixedly provided on a side portion of the guide cell 50, and a lower magazine support member 21 is provided for the magazine support slide 14. Is fixed. As described above, by supporting the support itself for supporting the magazine rack 22 and the clamp device 3 elastically in the vertical direction,
The rod R can be elastically supported while being indirectly movable in the rod axial direction.

On the other hand, as shown in FIG. 3, the lower magazine support member 21 is made movable with respect to the guide cell 50 (see FIG. 2) , and is supported via a load detector such as the load cell 12. Accordingly, when the outer tube / inner tube shafts 60 and 61 of the drifter 51 are connected to one rod R accommodated in the rod magazine 2, the screw part on the rod side and the screw on the drifter side are screwed or separated well. You will be able to clearly determine whether or not it is done. In other words, when screwing or unscrewing is not performed properly, the feed force or lifting force of the drifter is applied to the load cell, and the load detected by the load cell rises sharply. The state of screwing or separation can be confirmed.

In this embodiment, a spring is used as the elastic supporting means in the rod receiving portion and the clamp supporting portion. However, a damper structure by enclosing air or oil, a foamed resin having a high elastic modulus, or the like is used. It can also be elastically supported. In short, any structure can be used as long as the rod can move so as to absorb and reduce the impact when the rod receives an impact. Further, although the example of the double pipe rod has been described in detail, it is needless to say that a single pipe rod can be similarly applied.

Next, the procedure for adding rods will be described with reference to FIG.
This will be described in detail with reference to FIGS. The cylinder 10 is operated to rotate the rod magazine 2 to position the rod magazine 2 at a position where the supply rod coincides with the drilling axis O, that is, at a position shown in FIG. Rod receiving portion corresponding to the perforation axis O (hereinafter, referred to. Supply / recovery rod accommodating portion) when there is no rod, the hydraulic accession Chue over data 2
9 is driven and the magazine rack 22 is rotated to position the rod in the supply / recovery rod storage section. Then, the cylinder 49 is operated to move the clamp device 3 to the rod connection position as shown in FIG. 8, and the outer tube and the inner tube of the rod are clamped by the outer tube clamp 4 and the inner tube clamp 5.

By operating the cylinder 59 of the drifter 51 to lower the rotation driving device 58 for the inner tube to bring the inner tube shaft 61 into a state of protruding from the tip of the outer tube shaft 60, as shown in FIG. , Drifter 51
The inner pipe shaft 61 is lowered while rotating, and the inner pipe shaft 61 is screwed to the upper end of the inner pipe.

[0034] The clamp according to the tube clamp 5 is opened, by operating the cylinder 59 of Dorifuta 51, after pulled up the inner tube shaft 61 to raise the inner tube for rotary drive 58, the outer tube shaft Dorifuta 51 Lowering the outer tube while rotating the outer tube 60 and the outer tube shaft 60
Are screwed together.

[0035] opening the clamp by a outer tube clamp 4, slightly pulled upwardly Dorifuta 51, remove the outer tube from a lower end outer tube bushing 26c, thereby supporting the rod R in a suspended state by Dorifuta 51.

When the delivery of the rod to the drifter 51 is completed, the opening and closing frame 3
After opening 3, the cylinder 10 is operated to retract the rod magazine 2, and the cylinder 49 is operated to return the clamp device 3 to the original position.

The cylinder 59 is contracted, the rotation driving device 58 for the inner tube is lowered to make the inner tube protrude from the outer tube, and while the inner tube shaft 61 is rotated, the drifter 51 is lowered and the centrizer 54 for the inner tube is lowered. The lower end of the inner pipe is connected to the upper part of the penetrated inner pipe which is chucked by the above.

[0038] opening the chuck by St. riser 54 for the tube, after pulling up the inner tube slightly to extend the cylinder 59, while rotating the outer tube shaft 6 0 Dorifuta 5
1 is lowered to connect the lower end of the outer tube to the upper portion of the penetrated outer tube that is chucked by the outer tube sent riser 52 (the state shown in FIG. 13).

[0039] lowering the Dorifuta 51 performs penetration of rod, the drilling at the seam between the rod and the outer tube shaft 6 0 reaches the intermediate position between the outer tube for St. riser 52 and the outer pipe threading device 53 Stop.

When the upper end of the refill outer tube is chucked by the outer tube centrifuge 52, the screw is loosened by the outer tube screw cutting device 53, and the outer tube shaft 6 of the drifter 51 is removed.
The drifter 51 is lifted while rotating 0 in reverse to separate the drifter 51 from the outer tube.

[0041] Then, by placing a joint between the tube inner forceps Yafuto 61 shirttail between the inner pipe thread cutting device 55 and the inner tube for St. riser 54, the inner tube is chucked by the inner tube for St. riser 54, the inner After the screws are loosened by the pipe threading device 55, the drifter 51 is raised while rotating the inner pipe shaft 61 of the drifter 51 in the reverse direction, and the drifter 5 is removed from the inner pipe.
Disconnect 1

By repeating the above operations (1) to (4), drilling is performed by sequentially adding rods.

Next, the procedure for collecting the rod will be described with reference to FIGS.
Referring to FIG. 16 in detail, as shown in FIG. 14, the inner pipe and the outer pipe connected to the drifter 51 are pulled up together, and the lower end connecting portion of the outer pipe is connected to the outer pipe centrifuge 52 and the outer pipe screw. It is positioned between the cutting device 53.
After the outer pipe is clamped by the outer pipe centrifuge 52 and the screw is loosened by the outer pipe threading device 53, the drifter 51 is removed.
The outer tube shaft 60 is lifted while rotating in the reverse direction to separate the outer tube.

The lower end connecting portion of the inner pipe is positioned between the inner pipe centrifuge 54 and the inner pipe threading device 55, the inner pipe is clamped by the inner pipe centrifuge 54, and the screw is screwed by the inner pipe threading device 55. After loosening, the drifter 51
The inner pipe shaft 61 is lifted while rotating in the reverse direction to cut off the inner pipe.

After the lifter 51 has been sufficiently lifted, the opening / closing frame piece 33 of the rod guide members 31 and 32 is opened by operating the cylinder 34, and then the rod magazine 2 is rotated by operating the cylinder 10 and FIG. The rod magazine 2 is positioned at the position shown in FIG.

After lowering the drifter 51 slowly, inserting the support pin 23a for the inner tube into the inner tube and supporting the outer tube on the outer tube receiving cylinder 26c, the inner tube and the outer tube are clamped by the clamp device 3. Then, the inner tube shaft 61 and the outer tube shaft 60 of the drifter 51 are raised while rotating in the reverse direction to separate the drifter 51 from the rod, and the rod is housed in the magazine.

The rod magazine 2 is rotated and retracted, the clamp by the clamp device 3 is released, and the clamp device 3 is returned to the original position by operating the cylinder 49. Further, the magazine rack 22 is rotated to empty the supply / recovery rod storage section.

The rods are sequentially collected by repeating the above operations (1) to (4).

[0049]

As described above in detail, according to the present invention, when connecting / disconnecting the rod accommodated in the magazine and the rotary shaft of the drifter, even if the propulsive force of the drifter acts, the absorption is reduced. As a result, the thread of the rod or the rotating shaft is not crushed or the support member of the rod magazine or the clamp device is not damaged as in the related art.

[Brief description of the drawings]

FIG. 1 is a side view of a drilling machine equipped with a rod exchanging device according to the present invention.

FIG. 2 is an enlarged side view of a rod magazine portion.

FIG. 3 is an enlarged side view of a rod receiving portion of the rod magazine.

FIG. 4 is an enlarged front view of a rod receiving portion in the rod magazine.

FIG. 5 is a view taken along line VV of FIG. 2;

FIG. 6 is a view taken along line VI-VI of FIG. 2;

FIG. 7 is an enlarged view of the clamp device.

FIG. 8 is an operation state diagram of the rod clamp device.

FIG. 9 is a modified example of the rod magazine support mode.

FIGS. 10A and 10B are operation charts of the thread cutting device.

FIG. 11 is a supply procedure diagram (part 1) of a rod.

FIG. 12 is a supply procedure diagram (part 2) of a rod.

FIG. 13 is a supply procedure diagram (part 3) of a rod.

FIG. 14 is a drawing (part 1) of a rod collecting procedure.

FIG. 15 is a drawing (part 2) of a procedure for collecting rods.

FIG. 16 is a drawing (part 3) of a rod collecting procedure.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Rod exchange device, 2 ... Rod magazine, 3 ... Rod clamp device, 4 ... Outer tube clamp, 5 ... Inner tube clamp, 10 ... Cylinder, 11 ... Connecting tube, 12 ... Load cell, 13 ... Spring, 14 ... Magazine support Slide table, 15: fixed support table, 20: support material on magazine, 21
... Lower magazine support member, 22 ... Magazine rack, 23 ... Rod support plate, 23a ... Inner tube support pin, 24 ... Rack center shaft member, 26 ... Outer tube receiving member, 26c ... Outer tube receiving tube, 2
7, 28 ... spring, 29 ... hydraulic Aku Chue over data, 3
0 ... accession Chue over data support table 31, 32 ... rod guide member 42 ... clamp support member, 43 ... spring, 44
... Slide outer tube member

Claims (5)

(57) [Claims] 1. A rod exchanging device for supplying a rod to a drilling machine or recovering a rod from the drilling machine, wherein the rod exchanging device is disposed along a guide cell of the drilling machine, and has an outer peripheral portion. A rod magazine for supplying the rod on the guide cell or collecting the rod from the guide cell; and a rod receiving portion for the rod magazine or a support member for the rod magazine. A rod exchanging device, wherein a stored rod is elastically supported by a buffer means so as to be movable directly or indirectly in the longitudinal direction of the rod. 2. The rod exchanging device includes a rod clamp device for fixedly holding a predetermined rod in the rod magazine, and the clamp device is movable in a rod longitudinal axis direction through a buffer means. 2. The rod exchanging device according to claim 1, wherein the rod exchanging device is elastically supported in a proper state. 3. The rod exchanging device according to claim 1, wherein said buffer means has a spring member or a damper structure. 4. The rod magazine has an outer tube rod receiving portion and an inner tube receiving portion at the lower end of each of the accommodated rods, and the inner tube and the outer tube are both provided with a buffer means by providing a buffer means. While being elastically supported in the axial direction, the clamp device includes an outer tube clamp device for fixedly holding the outer tube and an inner tube clamp device for fixedly holding the inner tube, both of which are buffer means. The rod exchanging device according to claim 2, wherein the rod exchanging device is elastically supported in a state in which the rod exchanging member can move in the longitudinal direction of the rod through the intermediate member. 5. The rod exchanging device according to claim 1, further comprising a load detecting means for detecting a load acting on said rod magazine when connecting / disconnecting said drifter.