JP4920566B2 - Multiple bits - Google Patents

Description

  The present invention relates to a cutter bit that is attached to a cutter head of a tunnel excavator and cuts a face, and more particularly to a multiple bit that has a long life to cope with long-distance construction.

  A tunnel excavator generally includes a cutter head that is driven to rotate about an axis parallel to the excavation direction, and a cutter bit for cutting the face is attached to the cutter head. Since such cutter bits are worn by cutting the face, measures such as bit replacement are required for long-distance construction. A double bit is known as a cutter bit that has a long service life for long-distance construction (see Patent Document 1).

  As an example of a double bit, an inner bit attached to a cutter head, an outer bit that is bonded to the inner bit via a hot-melt adhesive and cuts the face while protecting the inner bit, and a hot-melt adhesive There is known a device provided with a heater provided in the inner bit for heating the inner bit. According to this double bit, after the outer bit is worn, by turning on the heater, the hot-melt adhesive is melted, the outer bit is removed from the inner bit, and the inner bit can be exposed.

  As other double bits, the inner bit attached to the cutter head, the outer bit formed to cover the inner bit, the adhesive that bonds the outer bit to the inner bit, and the outer bit is pushed away from the inner bit. For this reason, there is also known one provided with a cylinder provided inside the cutter head. According to this double bit, after the outer bit is worn, the cylinder can be extended to break the adhesive layer and push the outer bit away from the inner bit to expose the inner bit.

Japanese Patent Laid-Open No. 2003-3788

  According to these double bits, after the outer bit is worn, the heater and cylinder are activated to remove the outer bit and expose the inner bit, so that the unworn inner side that was previously protected by the outer bit Since the face can be cut with a bit, the life span is extended as a whole, and it can be used for long-distance construction.

  However, since an actuator such as a heater or a cylinder is used to remove the worn outer bit, an electric wire for operating the heater or a hydraulic line for operating the cylinder is disposed inside the cutter head. Need arises. In addition, a rotary joint is required to supply electric current and hydraulic pressure from the pit to the electric wires and hydraulic lines arranged in the rotating cutter head. Therefore, the structure becomes complicated and the cost increases.

  An object of the present invention created in view of the above circumstances is to provide a multiple bit in which the outer bit is detached and the inner bit is exposed without using an actuator when the outer bit is worn by a predetermined amount.

  In order to achieve the above object, a multiple bit according to the present invention is a multiple bit mounted on a cutter head of a tunnel excavator to cut a face, and is attached to the cutter head directly or via a pedestal. An inner bit; an outer bit attached to the inner bit so as to cover the inner bit; and a wedge member fixed to the pedestal or the cutter head and pressing the outer bit against the inner bit. A contact surface between the member and the outer bit and a contact surface between the outer bit and the inner bit are formed in parallel with an axis in a direction crossing the cutting direction of the outer bit when the cutter head is operated. A restraining member for restraining movement along the direction of the axis with respect to the inner bit.

  It is preferable that a contact surface between the wedge member and the outer bit and a contact surface between the outer bit and the inner bit are formed so as to be widened in a direction away from the inner bit.

  The restraining member may have a through pin inserted into a through hole formed at one end of the outer bit through the inner and outer surfaces and the other end inserted into a recess formed at the inner bit.

  The restraining member may have a side plate having one end fixed to the side portion of the outer bit and the other end in contact with the side portion of the inner bit.

  The restraining member may have a convex portion or a concave portion formed in the wedge member and a concave portion or a convex portion formed in the outer bit so as to engage with the convex portion or the concave portion.

  The restraining member may have a protruding portion that is provided so as to protrude from the inner surface of the outer bit and is inserted into a recess formed in the inner bit.

  According to the multiple bit according to the present invention, when the outer bit is worn by a predetermined amount, the outer bit is detached without using the actuator, and the inner bit is exposed. Since an actuator is not required, an electric wire, a hydraulic line, a rotary joint, etc. for operating the actuator are not required, and the structure around the cutter head is simplified and cost reduction can be promoted.

  Preferred embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a side sectional view of a tunnel excavator (shield excavator) having a cutter head to which a multiple bit according to this embodiment is attached, and FIG. 2 is a front view of the shield excavator as viewed from the front in the excavation direction. is there.

  The shield machine 1 includes a cylindrical shield frame 2, a partition 3 that partitions the shield frame 2 forward and backward in the digging direction, and a cutter head 4 that is supported by the partition 3 so as to be rotatable about an axis parallel to the digging direction. An erector (not shown) for assembling the segments in the shield frame 2 in a ring shape, and a shield jack for advancing the shield frame by taking a reaction force on the segments assembled on the inner surface of the shield frame 2 and assembled in the ring shape (see FIG. Not shown).

  The cutter head 4 has a central portion 5 disposed at the rotation center X and a plurality of cutter spokes 6 radially attached to the central portion 5 at intervals in the circumferential direction. By the driving means, it is rotated clockwise or counterclockwise around the rotation center X. A triangular plate-shaped fishtail bit 7 is attached to the center portion 5, and a plurality of multiple bits 8 according to the present embodiment are attached to the cut spoke 6 at intervals in the radial direction.

  The fishtail bit 7 and the multiple bit 8 are pressed against the face by extending the shield jack, and the cutter head 4 is rotated in this state to cut the face. Arrows A and B in FIG. 2 indicate a cutting direction in which the multiple bit 8 cuts the face as the cutter head 4 rotates, and is a tangential direction of a circle around the rotation center X.

  The cutter head 4 is a spoke type in this embodiment, but may be a face plate type.

  3 is a cross-sectional view taken along the line III-III in FIG. 2, FIG. 4A is a partially enlarged view of FIG. 3, and FIG. 4B is a front view of the multiple bit shown in FIG.

  The multiple bit 8 according to the present embodiment is fixed to the pedestal 9, the inner bit 10 attached to the cutter head 4 via the pedestal 9, the outer bit 11 attached to the inner bit 10 so as to cover the inner bit 10, and the pedestal 9. A wedge member 12 that presses the outer bit 11 against the inner bit 10.

  The base 9 may be omitted, the inner bit 10 may be directly attached to the cutter head 4, and the wedge member 12 may be directly attached to the cutter head 4. However, if the inner bit 10 and the wedge member 12 are attached to the pedestal 9 as in this embodiment, the inner bit 10, the wedge member 12 and the outer bit 11 attached to the pedestal 9 are attached to the cutter head 4 as an integrated assembly. Can be convenient.

  The pedestal 9 is made of a plate that is bent in an L-shaped cross section so as to be attached to a corner portion connecting the face on the face side of the cutter pork 6 and the face on the front side in the rotation direction. The front surface portion 9 a is seated on the front surface, and the side surface portion 9 b is seated on the front surface in the rotational direction of the cutter spoke 6. 9 w is a weld bead formed by welding the pedestal 9 to the cutter pork 6.

  The inner bit 10 has an inner shank 10a as a base welded to the pedestal 9, and an inner carbide tip 10b as a cutting blade brazed to the front portion in the cutting direction A of the inner shank 10a. The inner shank 10a is made of an SS material or the like, and the inner carbide tip 10b is made of a cemented carbide such as tungsten carbide. 10 w is a weld bead formed by welding the inner shank 10 a to the base 9.

  The outer bit 11 includes an outer shank 11a (SS material or the like) formed so as to cover the inner bit 10, and an outer carbide chip 11b (tungsten carbide or the like) brazed to the front portion in the cutting direction A of the outer shank 11a. ). The outer shank 11a includes a front cover portion 11c that covers the front portion 10c of the inner bit 10 (a portion in the cutting direction front A), a rear cover portion 11d that covers the face side portion 10d of the inner bit 10, and the front cover portion 11c and the rear. A wear portion 11e that connects the cover portion 11d, a front claw portion 11f that is formed on the end portion of the front cover portion 11c so as to protrude toward the inner bit 10 side, and an inner bit 10 side that is formed on the end portion of the rear cover portion 11d. And a rear claw portion 11g formed to project. The front claw portion 11f is brought into contact with a front engagement portion 10f formed to protrude in a jaw shape at the front portion in the excavation direction A on the inner shank 10a, and the rear claw portion 11g is in the excavation direction A on the inner shank 10a. It is in contact with a rear engagement portion 10g formed to protrude in the shape of a jaw at the rear portion.

  The wedge member 12 includes a front wedge member 12a (SS material or the like) welded to the pedestal 9 in a state where the front claw portion 11f of the outer bit 11 is pressed against the front engagement portion 10f of the inner bit 10, and the rear portion of the outer bit 11. It consists of a rear wedge member 12b (SS material or the like) welded to the base 9 in a state where the claw portion 11g is pressed against the rear engagement portion 10g of the inner bit 10. Reference numeral 12w denotes a weld bead formed by welding the front wedge member 12a and the rear wedge member 12b to the pedestal 9, respectively.

  The contact surface 13 between the front wedge member 12a and the front claw portion 11f and the contact surface 14 between the front claw portion 11f and the front engagement portion 10f are in the radial direction C of the cutter head 4 (longitudinal direction of the cutter spoke 6). In the direction perpendicular to the axis along the axis, it is formed so as to be divergent in a direction away from the inner bit 10. Similarly, the contact surface 15 between the rear wedge member 12b and the rear claw portion 11g and the contact surface 16 between the rear claw portion 11g and the rear engagement portion 10g are formed in a divergent direction in a direction away from the inner bit 10. ing.

  That is, the contact surface 13 and the contact surface 14 are formed in a divergent direction in a direction away from the inner bit 10, and the contact surface 15 and the contact surface 16 are formed in a divergent direction in a direction away from the inner bit 10. The opening angle θ1 of the contact surfaces 13 and 14 and the opening angle θ2 of the contact surfaces 15 and 16 are set to be the same in the present embodiment, but may be different.

  These contact surfaces 13 to 16 are axes in a direction C that crosses the cutting direction A of the outer bit 11 by the operation of the cutter head 4 (in this embodiment, an axis along the radial direction of the cutter head 4, hereinafter also referred to as axis C). Each is formed in parallel. Thereby, when the cutter head 4 rotates and the outer bit 11 receives a cutting reaction force from the face, the cutting reaction force can be supported by the contact surfaces 13 to 16 formed in parallel with the axis C.

  The axis C does not necessarily have to be along the radial direction of the cutter head 4. The axis C is not limited to the radial direction of the cutter head 4 as long as the direction crosses the cutting direction A of the outer bit 11 by the operation of the cutter head 4. May be slightly inclined. This is because even if the axis C is slightly inclined from the radial direction of the cutter head 4, the cutting reaction force received by the outer bit 11 from the face can be supported by the contact surfaces 13 to 16 formed parallel to the axis C.

  By the way, in the multiplex bit 8 having such a configuration, when the cutter head 4 is rotated with the multiplex bit 8 being pressed against the face in FIG. On the other hand, it may move in the direction of the axis C and come off the inner bit 10.

  That is, when the cutter head 4 is rotated with the multiple bit 8 pressed against the face, most of the cutting reaction force applied from the face to the outer bit 11 is centered on the cutting direction A (the rotation center X of the cutter head 4). However, the lateral force in the direction along the radial axis C of the cutter head 4 is partially generated by the excavated earth and sand flowing in the radial direction of the cutter head 4, Due to this lateral force, the outer bit 11 may be displaced along the contact surfaces 13 to 16 formed in parallel with the axis C, and may be detached from the inner bit 10.

  Therefore, as shown in FIGS. 4A and 4B, the multiple bit 8 includes a restraining member 17 that restrains the movement of the outer bit 11 with respect to the inner bit 10 along the direction of the axis C. Yes. The restraining member 17 has a through pin 17 c that is fixed to a through hole 17 a formed in the outer bit 11 at one end and inserted into a recess 17 b formed in the inner bit 10 at the other end. The through hole 17 a is formed through the inner and outer surfaces of the rear cover portion 11 d of the outer bit 11, and the concave portion 17 b is formed in the face side portion 10 d of the inner bit 10. The through pin 17c includes a large diameter portion and a small diameter portion, the large diameter portion is welded to the through hole 17a, and the small diameter portion is inserted into the concave portion 17b.

  The through hole 17a is a long hole (land track type) that is elongated in the direction of the axis C in accordance with the diameter of the large diameter portion of the through pin 17c. The through hole 17a accommodates molten metal when welding the large diameter portion of the through pin 17c, and the molten metal is solidified to form a weld 17d indicated by dots. The concave portion 17b is formed of a long hole (land track type) that is elongated in a direction F perpendicular to the axis C in accordance with the diameter of the small diameter portion of the penetrating pin 17c. Due to the concave portion 17b having this shape, the small-diameter portion of the penetrating pin 17c is pressed so as not to move in the direction of the axis C, and is easily removed in the direction F perpendicular to the axis C.

  The hole axis of the through-hole 17a and the hole axis of the recess 17b are coincident with each other when the outer bit 11 is attached to the inner bit 10. This is because the through pin 17c welded to the through hole 17b is appropriately inserted into the recess 17b.

  The hole shafts 17x of the through holes 17a and the recesses 17b are parallel to an axis 11x (intermediate shaft) that passes between the contact surface 15 and the contact surface 16, as shown in FIG. . Specifically, the hole shaft 17x and the intermediate shaft 11x are parallel to each other in a plane orthogonal to the longitudinal axis of the cutter pork 6 (the back and front direction in FIG. 4A).

  Thereby, when the wear part 11e is worn away as shown in FIG. 6 and the rear cover part 11d and the front cover part 11c are separated, the rear claw part 11g of the rear cover part 11d is connected to the inner bit 10 and the rear wedge member. The direction deviating from 12b is generally the direction of the intermediate shaft 11x. If the intermediate shaft 11x and the hole shaft 17x are parallel, the axis of the small diameter portion of the through pin 17c is the hole axis of the recess 17b. , The small diameter part comes out of the recess 17b, and the rear cover part 11d is easily detached.

  In the present embodiment, a gap 18 (see FIG. 3) is provided between the outer bit 11 and the inner bit 10, but this is because the shanks 10a, 11a of the respective bits 10, 11 are forged products and have no gap. This is because it is difficult to ensure the close contact accuracy. Therefore, the outer bit 11 is supported only by the front and rear claw portions 11f and 11g being sandwiched between the front and rear wedge members 12a and 12b and the front and rear engagement portions 10f and 10g, respectively. Strength calculation is easy. However, the gap 18 may be brought into contact with the gap 18 partially or entirely as substantially zero.

  The operation of this embodiment will be described.

  As shown in FIG. 5, the outer bit 11 cuts the face K by the rotation of the cutter head 4 and the advance of the tunnel excavator. The outer bit 11 has a front claw portion 11f sandwiched between the front wedge member 12a and the front engagement portion 10f, and a rear claw portion 11g sandwiched between the rear wedge member 12b and the rear engagement portion 10g. And has a mounting rigidity that can sufficiently support the cutting reaction force. That is, the cutting reaction force that the outer bit 11 receives from the face K is supported by the contact surfaces 13 to 16 that are formed in parallel with the axis C in the direction crossing the cutting direction A of the outer bit 11.

  When the cutter head 4 rotates in the cutting direction A indicated by the arrow, the outer bit 11 receives the cutting reaction force from the face K and is pushed to the right in FIG. 5, whereby the front claw portion 11 f of the outer bit 11 is pressed. It fits like a wedge between the contact surface 13 and the contact surface 14 which are tapered in the direction. Further, when the cutter head 4 rotates in the cutting direction A, a clockwise moment is generated in the outer bit 11 to cause the outer bit 11 to fall to the right in FIG. Thus, the rear claw portion 11g of the outer bit 11 is fitted like a wedge between the contact surface 15 and the contact surface 16 which are tapered in the direction of the moment. As a result, the mounting rigidity of the outer bit 11 is increased.

  2 and 5, when the cutter head 4 is rotated in a state where the outer bit 11 is pressed against the face K in FIGS. 2 and 5, the outer bit 11 is moved against the inner bit 10 by the cutting reaction force. Although a lateral force that tends to move in the radial direction C of 4 can be generated, this lateral force is supported by the through pin 17c. That is, even if the outer bit 11 receives a lateral force and tries to move in the radial direction of the cutter head 4 with respect to the inner bit 10, the tip (small diameter portion) of the through pin 17c fixed to the through hole 17a of the outer bit 11 remains. By being pressed against the side surface of the recess 17b of the inner bit 10, the movement of the outer bit 11 relative to the inner bit 10 is prevented. Therefore, during cutting of the face K, the outer bit 11 does not shift with respect to the inner bit 10, and appropriate cutting can be maintained.

  When the outer bit 11 cuts the face K, the outer carbide tip 11b and the wear part 11e gradually wear. As wear progresses, the thickness of the wear portion 11e connecting the front cover portion 11c and the rear cover portion 11d of the outer shank 11a becomes thinner, and the stress generated there increases. When the wear proceeds to a predetermined amount, as shown in FIG. 6, the wear portion 11e is broken, and the outer bit 11 is replaced with a front piece 11h comprising a front cover portion 11c and a front claw portion 11f, a rear cover portion 11d and a rear claw portion. It is divided into rear pieces 11i made of 11g.

  The divided front piece 11h is such that the contact surface 14 between the front claw portion 11f and the front engagement portion 10f and the contact surface 13 between the front claw portion 11f and the front wedge member 12a are separated from the inner bit 10. Because of the widening at the end, the front claw portion 11h is disengaged in the direction of the arrow D due to fine vibration or lateral force generated by the rotation of the cutter head 4, or by reverse rotation of the cutter head 4, and the like. take off.

  In the rear piece 11i, the contact surface 16 between the rear claw portion 11g and the rear engagement portion 10g and the contact surface 15 between the rear claw portion 11g and the rear wedge member 12b are divergent in a direction away from the inner bit 10. Therefore, the rear claw portion 11g is detached in the direction of the arrow E by the fine vibration or lateral force generated by the rotation of the cutter head 4 or by reversely rotating the cutter head 4, and falls off the cutter head 4. At this time, the small-diameter portion of the through pin 17c fixed to the rear piece 11i is pulled out from the concave portion 17b of the inner bit 10.

  Here, the recess 17b is formed in an elongated slot shape along the direction F (see FIG. 4A) orthogonal to the radial direction C of the cutter head 4, that is, the excavation direction A in FIG. 4B. When the small diameter portion of the penetrating pin 17c is pulled out from the recess 17b due to the reaction force from the face K being received by the rear cover portion 11i, the small diameter portion of the penetrating pin 17c moves somewhat along the excavation direction A in the recess 17b. It is acceptable. Therefore, the small diameter part of the penetration pin 17c is smoothly extracted from the recess 17b without resistance.

  Then, as shown in FIG. 7, the inner bit 10 that has been covered by the outer bit 11 so far and has not been worn out is exposed, and the face K can be cut by the new inner bit 10.

  Thus, according to the present embodiment, the outer bit 11 that has reached the wear limit is automatically dropped from the cutter head 4, and cutting can be continued by the inner bit 10 that has been protected from wear by the outer bit 11 until then. Therefore, the life of the entire bit is extended, and it can be used for long-distance construction.

  Further, according to the present embodiment, as shown in FIGS. 5 and 6, when the outer bit 11 is worn down to a predetermined amount (wear limit), stress concentrates on the wear portion 11e and breakage occurs. The outer bit 11 is removed without using the heater or cylinder of Document 1, and the inner bit 10 is exposed. Since an actuator is unnecessary, there is no need for an electric wire or hydraulic line arranged in the cutter head 4 to operate it, and a rotary joint for supplying electric current or hydraulic pressure to the electric wire or hydraulic line is unnecessary. The structure around the cutter head 4 is simplified, and cost reduction can be promoted.

  In this embodiment, as shown in FIG. 4A, the contact surfaces 13 and 14 are formed so as to be divergent in a direction away from the inner bit 10, and similarly, the contact surfaces 15 and 16 are separated from the inner bit 10. However, the present invention is not limited to this, and it may be formed parallel or tapered. The front piece 11h shown in FIG. 6 moves in the direction of the axis C along the contact surfaces 13 and 14 by the fine vibration generated by the rotation of the cutter head 4, the lateral force, or by reversely rotating the cutter head 4. The rear piece 11i is slightly rotated clockwise in FIG. 6 and moved along the contact surfaces 15 and 16 with the tip of the penetrating pin 17c pulled out from the recess 17b. This is because it moves away from the inner bit 10 by moving in the direction of the axis C.

  Hereinafter, modified embodiments of the present invention will be described with reference to FIGS.

  The modified embodiment of FIGS. 8 to 11 is different from the previous embodiment only in the restraining member 17 that restrains the movement of the outer bit 11 relative to the inner bit 10, and the other configuration is the same as in the previous embodiment. Has an effect. That is, the outer bit 11 is movable with respect to the inner bit 10 along the contact surfaces 13 to 16, and this movement is restrained by the restraining member 17 described below.

  The restraint member 17 of the modified embodiment shown in FIG. 8 includes a side plate 17e having one end welded and fixed to the side portion 11j of the outer bit 11 and the other end abutting the side portion of the inner bit 10. The side plate 17e includes an outer side plate 17e welded and fixed to the outer side of the outer bit 11 (the outer side in the radial direction C of the cutter head 4), and the inner side of the outer bit 11 (in the radial direction C of the cutter head 4). The inner side plate 17e is welded and fixed to the inner side portion. The width dimension of the inner bit 10 (dimension in the radial direction C of the cutter head 4) is equal to the width dimension of the outer bit 11 at the portion where the outer and inner side plates 17e face each other, and the outer and inner side plates 17e. Is in contact with the side of the inner bit 10. These outer and inner side plates 17e restrain the movement of the outer bit 11 along the axis C with respect to the inner bit 10.

  The constraining member 17 of the modified embodiment shown in FIG. 9 includes convex portions or concave portions 17f formed in the wedge members 12a and 12b, and concave portions or concave portions formed in the outer bit 11 so as to engage with these convex portions or concave portions 17f. And a convex portion 17g. Specifically, the contact surface 13 of the front wedge member 12a is formed with a convex portion or a concave portion 17f, and the front claw portion 11f of the outer bit 11 is formed with a concave portion or a convex portion 17g. Further, the contact surface 15 of the rear wedge member 12b is formed with a convex portion or a concave portion 17f, and the rear claw portion 11g of the outer bit 11 is formed with a concave portion or a convex portion 17g. The movement along the axis C of the outer bit 11 with respect to the inner bit 10 is restricted by the convex portions and the concave portions 17f and 17g.

  The details of the convex or concave portion 17f and the concave or convex portion 17g are shown in FIG. In this modified embodiment, a key (male side) is provided as a convex portion 17f on the rear wedge member 12b as shown in FIG. 10 (a), and a rear claw portion 11g of the outer bit 11 as shown in FIG. 10 (b). A groove (female side) is provided as a recess 17g. Similarly, although not shown, the front wedge member 12a is provided with a key as a convex portion 17f, and the front claw portion 11f of the outer bit 11 is provided with a groove as a concave portion 17g. After the key 17f and the groove 17g are fitted, the front wedge member 12a and the rear wedge member 12b are welded to the base 9, so that the axis C shown in FIG. Constrains movement along. The relationship between the key and the groove may be reversed.

  The restraint member 17 of the modified embodiment shown in FIG. 11 has a projecting portion 17 i that projects from the inner surface of the outer bit 11 and is inserted into a recess 17 h formed in the inner bit 10. Specifically, a protrusion 17i is provided in a rib shape along the cutting direction A on the inner surface of the rear cover portion 11d of the outer bit 11, and the protrusion 17i is just engaged with the face side portion 10d of the inner bit 10. A recessed portion 17h formed so as to be formed is provided. The movement along the axis C with respect to the inner bit 10 of the outer bit 11 is constrained by the protrusion 17i and the recess 17h.

  In the modified embodiment of FIG. 12, the present invention (multiple bit) is applied to a bit corresponding to excavation in both directions of clockwise rotation and counterclockwise rotation of the cutter head 4 with one bit.

  The multiple bit 8 according to this modified embodiment includes an inner bit 10 welded to the face side 4a (cutter face) of the cutter head 4, an outer bit 11 attached to the inner bit 10 so as to cover the inner bit 10, It has a wedge member 12 (front wedge member 12a, rear wedge member 12b) that is welded to the cutter face 4a and presses the outer bit 11 against the inner bit 10.

  The inner bit 10 has an inner shank 10a welded to the cutter face 4a, a triangular roof (gable roof) -shaped inner carbide tip 10b fixed to the top of the inner shank 10a by brazing, and the like. The inner cemented carbide tip 10b can cut the face regardless of whether the cutter head 4 rotates in the arrow A direction or the arrow B direction. The inner bit 10 may be welded to a pedestal (not shown) welded to the cutter face 4a.

  The outer bit 11 includes a front outer shank 11k formed so as to cover the front side surface of the inner bit 10 in the direction of arrow A, and a rear outer shank 11m formed so as to cover the rear side surface of the inner bit 10. The outer shank 11k, 11m has an outer cemented carbide tip and 11b formed in a triangular roof shape over the top of the outer shank 11k, 11m and fixed to the top of the outer shank 11k, 11m by brazing or the like. Even if the cutter head 4 rotates in the direction of arrow A or in the direction of arrow B, the face can be cut.

  The front outer shank 11k has a front claw portion 11n inserted into a front concave portion 10h formed in the inner shank 10, and the front claw portion 11n is formed by the front wedge member 12a welded to the cutter face 4a. It is pressed against the ceiling surface. Similarly, the rear outer shank 11m has a rear claw portion 11p inserted into a rear recess 10i formed in the inner shank 10a, and the rear claw portion 11p is rearward by a rear wedge member 12b welded to the cutter face 4a. It is pressed against the ceiling surface of the recess 10i. The wedge members 12a and 12b may be welded to the pedestal (not shown) welded to the cutter face 4a.

  Contact surface 14 between front claw portion 11n and front recess 10h, contact surface 13 between front claw portion 11n and front wedge member 12a, contact surface 16 between rear claw portion 11p and rear recess 10i, rear claw portion 11p and rear wedge The contact surface 15 with the member 12b is formed in parallel with an axis in a direction crossing the rotational directions A and B of the cutter head 4 (in this embodiment, an axis along the radial direction of the cutter head 4: the axis C in FIG. 2). ing. As a result, when the cutter head 4 rotates in the direction of the arrow A or B and the outer bit 11 receives a cutting reaction force from the face, the cutting reaction force is formed in contact surfaces 13 to 16 formed parallel to the axis C. Can support.

  The axis C does not necessarily have to be along the radial direction of the cutter head 4, and is slightly inclined with respect to the radial direction of the cutter head 4 as long as the direction crosses the cutting direction A of the outer bit 11 and the inner bit 10. It does not matter. This is because even if the axis C is slightly inclined from the radial direction of the cutter head 4, the cutting reaction force received by the outer bit 11 from the face can be supported by the contact surfaces 13 to 16 formed parallel to the axis C.

  The multiple bit 8 includes a restraining member 17 that restrains the movement of the outer bit 11 with respect to the inner bit 10 along the direction of the axis C. The restraining member 17 has one end fixed to a through hole 17a formed through the inner and outer surfaces of the outer shanks 11k and 11m, and the other end provided with a through pin 17c inserted into a recess 17b formed in the inner shank 10a. Have.

  The penetrating pin 17c includes a small-diameter shaft portion and a large-diameter head portion, the head portion is accommodated in a recess formed in the outer shanks 11k and 11m, and the middle portion of the shaft portion is a through-hole in the outer shanks 11k and 11m. 17a is inserted and fixed. As the fixing method, press-fitting, screwing, welding or the like is used. The tip of the shaft portion of the penetrating pin 17c is inserted into the concave portion 17b of the inner shank 10a. The size of the concave portion 17b in the front and back directions in FIG. 12 matches the diameter of the shaft portion of the penetrating pin 17c so that the shaft portion does not move in the back and front direction in FIG.

  Also in this modified embodiment, when the cutter head 4 rotates in the direction of arrow A or B and the outer carbide tip 11b is worn to some extent by cutting the face, the outer carbide tip 11b is divided into right and left in FIG. Then, the connection between the front outer shank 11k and the rear outer shank 11m is released. Then, the outer shanks 11k and 11m are rotated so as to be slightly opened by fine vibrations caused by the rotation of the cutter head 4, the lateral force, or the cutter head 4 is reversely rotated. In a state where the shaft portion of 17c is pulled out from the concave portion 17b, the shaft portion is detached from the inner bit 10 by moving in the direction of the axis C along the contact surfaces 13 and 14 and the contact surfaces 15 and 16. Therefore, there exists an effect similar to 1st embodiment.

  To describe still another modified embodiment, it is not shown in FIG. 4 (a), FIG. 8 (a), FIG. 9 (a), FIG. 11 (a), and FIG. Another outer bit (second outer bit) is further provided, and another front wedge member (second front wedge member) that presses the front end of the second outer bit against the outer bit 11 (first outer bit) is a front wedge member 12a ( The rear wedge member 12b (second rear wedge member) is fixed (welded) to the first front wedge member) or the base 9, and another rear wedge member (second rear wedge member) that presses the rear end of the second outer bit against the first outer bit 11. 1 rear wedge member) or pedestal 9 (welded) and may be a triple bit.

  Also in this triple bit, the direction C in which the contact surface between the second front wedge member and the second outer bit and the contact surface between the second outer bit and the first outer bit cross the cutting direction A of the second outer bit. A restraining member that restrains the movement of the second outer bit with respect to the first outer bit 11 along the direction C of the shaft (the penetrating pin 17c, the side plate 17e, the convex portion and the concave portion 17f, 17g, the same as the protrusion 17i and the recess 17h). Moreover, it is preferable that each said contact surface is formed so that it may spread in the direction away from the 1st outer side bit 11 (it is the same also with the inner side bit 10).

  According to this triple bit, when the second outer bit is worn by a predetermined amount, the second outer bit is divided into front and rear and dropped out from the first outer bit 11, and thereafter the state shown in FIG. The operation can be continued, and the same effect as the above-described double bit can be obtained.

  Similarly, quadruple bits or more are possible.

  In the above embodiment, the restraining member 17 (the through pin 17c, the side plate 17e, and the projecting portion 17i) is fixed to the outer bit 11. However, these may be fixed to the inner bit 10.

It is a sectional side view of the tunnel excavator (shield machine) which has the cutter head with which the multiple bit which concerns on this embodiment was mounted | worn. It is the front view which looked at the above-mentioned shield machine from the front in the digging direction. It is the III-III sectional view taken on the line of FIG. 4A is a partially enlarged view of FIG. 3 and is a cross-sectional view taken along the line IV-IV of FIG. 4B. FIG. 4B is a front view of the multiple bit shown in FIG. And it is also the elements on larger scale of FIG. It is a sectional side view which shows a mode that a face is cut with the multiple bit which concerns on this embodiment. It is a sectional side view which shows a mode that abrasion of the outer side bit advanced and it was damaged. It is sectional drawing which shows a mode that a face is cut with an inner side bit. It is explanatory drawing of the multiple bit which concerns on deformation | transformation embodiment, Fig.8 (a) is a side sectional view (VIII-VIII sectional view taken on the line of FIG.8 (b)), FIG.8 (b) is a front view. It is explanatory drawing of the multiple bit which concerns on another deformation | transformation embodiment, Fig.9 (a) is a side sectional view (IX-IX sectional view taken on the line of FIG.9 (b)), FIG.9 (b) is a front view. 10 (a) is a perspective view of the rear wedge member shown in FIG. 9 (a), and FIG. 10 (b) is a perspective view of the rear claw portion of the outer bit shown in FIG. 9 (a). It is explanatory drawing of the multiplex bit which concerns on another modification embodiment, Fig.11 (a) is a side sectional view (XI-XI sectional view taken on the line of FIG.11 (b)), FIG.11 (b) is a front view. . It is a sectional side view of the multiplex bit concerning another modification embodiment.

Explanation of symbols

4 Cutter head 8 Multiple bit 9 Base 10 Inner bit 11 Outer bit 11j Side portion 12 Wedge member 13 Contact surface 14 Contact surface 15 Contact surface 16 Contact surface 17 Restraining member 17a Through hole 17b Recess 17c Through pin 17e Side plate 17f Projection or recess 17g Concave portion or convex portion 17h Depressed portion 17i Protruding portion K Face A, B Cutting direction C Direction crossing cutting direction

Claims (6)

A multi-bit mounted on the cutter head of a tunnel excavator to cut the face,
An inner bit attached directly or via a pedestal to the cutter head;
An outer bit attached to the inner bit so as to cover the inner bit;
A wedge member fixed to the pedestal or the cutter head and pressing the outer bit against the inner bit;
A contact surface between the wedge member and the outer bit and a contact surface between the outer bit and the inner bit are formed in parallel with an axis in a direction crossing a cutting direction of the outer bit when the cutter head is operated,
A multiple bit comprising a restraining member for restraining movement of the outer bit along the direction of the axis with respect to the inner bit.   2. The multiple bit according to claim 1, wherein a contact surface between the wedge member and the outer bit and a contact surface between the outer bit and the inner bit are formed so as to be divergent in a direction away from the inner bit.   2. The restraint member has a through pin inserted into a through hole formed at one end of the outer bit through the inner and outer surfaces thereof and inserted into a recess formed at the inner bit. 2. Multiple bits according to 2.   3. The multiple bit according to claim 1, wherein the restraining member has a side plate having one end fixed to the side portion of the outer bit and the other end abutted to the side portion of the inner bit.   The said restraint member has a convex part or a recessed part formed in the said wedge member, and a recessed part or a convex part formed in the said outer side bit so that these convex parts or a recessed part may be engaged. Multiple bits.   3. The multiple bit according to claim 1, wherein the restraining member has a protruding portion that protrudes from an inner surface of the outer bit and is inserted into a recess formed in the inner bit. 4.

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