JP4649664B2 - Folding parent and child shield - Google Patents

Description

  The present invention relates to a middle folding type parent-child shield in which a middle folding type child shield starts from a middle folding type parent shield, and more particularly to a middle folding type parent-child shield designed to reduce costs.

  2. Description of the Related Art As a middle-folding type parent-child shield, a child shield in which a front trunk and a rear trunk can be bent is started from a parent shield in which a front trunk and a rear trunk can be bent. This type of conventional center-foldable parent-child shield is such that the front shield and the back torso of the parent shield are flexibly connected by a center-break mechanism, and the front and rear torso of the child shield are separate from each other. (Refer to Patent Documents 1 and 2).

  Here, the center bending mechanism includes a spherical bearing, a center bending pin, and the like that connect the front cylinder and the rear cylinder so that they can be bent.

Japanese Patent No. 3605877 Japanese Patent No. 2647356

  By the way, the middle folding mechanism not only connects the front and rear cylinders so that they can be bent, but also needs to stop water between the front and rear cylinders, so it must be manufactured with high precision by cutting or the like. is there. Therefore, providing the middle folding mechanism, which is a highly accurate component, separately for the parent shield and the child shield causes an increase in cost.

  An object of the present invention, which was created in view of the above circumstances, is to provide a center-foldable parent-child shield that achieves cost reduction by sharing the center-folding mechanism between the child shield and the parent shield.

In order to solve the above-mentioned object, the present invention is a middle-foldable parent-child shield in which a front shield and a rear shell can be bent, and a front shield and a rear shell can be bent. The front body of the parent shield is fitted to the outer periphery of the front body of the child shield so as to be detachable by a front body fixing device, and the rear body of the parent shield is attached to the outer periphery of the rear body of the child shield by the rear body fixing device. connection separation capable fitted over, and connected through a center-folding jack with connecting bendable through the center bending mechanism and a front cylinder and a rear cylinder of said child shield body rear and front torso of said child shield And by connecting the front trunk and the rear trunk of the parent shield connected via the front trunk fixing device and the rear trunk fixing device to each other in a bendable manner through the middle folding mechanism and the middle folding jack of the child shield. , the parent of the jack broken mechanism and in the above-mentioned bending in the above Shared the bending of the front cylinder and the rear body of Rudo, diameter barrel after the parent shield, from its outer peripheral surface with is extended forwardly so that polymerization on the outer peripheral surface and the front-rear direction of the front torso of said child shield It has an extension part spaced outward in the direction, and the extension jack is provided with the shield jack for the parent shield .

It is preferable that the extension portion has a smaller diameter than the outer diameter of the front body of the parent shield .

It is preferable that the extending portion is formed in a bag shape having a ring-shaped opening at the rear, and a shield jack of a parent shield is provided therein .

According to the middle folding type parent-child shield according to the present invention, the middle folding mechanism and middle folding jack of the child shield are shared by the parent shield, and the rear trunk of the parent shield is connected to the outer peripheral surface of the front trunk of the child shield. Since it has an extension part that extends forward so as to overlap in the front-rear direction and is spaced radially outward from the outer peripheral surface, and the extension jack is provided with the shield jack for the parent shield, the parent shield A dedicated middle folding mechanism and middle folding jack are not required, so that the cost can be reduced and the length of the main shield can be shortened .

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

  As shown in FIGS. 1 and 5, the center-foldable parent-child shield 1 according to this embodiment is configured such that the front trunk 40 and the rear trunk 50 are bent from the parent shield 30 in which the front trunk 10 and the rear trunk 20 can be bent. The possible child shield 60 starts. FIG. 1 is a side sectional view when the parent shield 30 is excavated, and FIG. 5 is a side sectional view showing a state immediately before the child shield 60 starts from the parent shield 30.

  First, the child shield 60 incorporated in the parent shield 30 will be described.

  As shown in FIG. 1, the child shield 60 includes a front cylinder 40 and a rear cylinder 50 formed in a cylindrical shape having the same diameter, and a middle folding mechanism 70 that connects the front cylinder 40 and the rear cylinder 50 so as to be bendable. Have.

  A partition 41 that partitions the interior of the front barrel 40 forward and backward is provided. The partition 41 includes a cutter driving mechanism 81 for rotationally driving a child shield cutter 80 disposed in front of the partition, and a partition. A soil removal device 83 is provided for taking excavated earth and sand in the cutter chamber 82 formed between 41 and the cutter 80 into the mine.

  The cutter driving mechanism 81 includes a rotating plate 84 connected to the cutter 80, a cylinder 85 attached to the rotating plate 84, a bearing housing 86 that supports the cylinder 85 via a radial bearing and a thrust bearing, and a bearing housing. A bracket 87 for fixing 86 to the partition wall 41 and a drive motor 88 attached to the bracket 87, and a pinion provided on the rotation shaft of the drive motor 88 is engaged with an external gear provided on the outer periphery of the cylinder 85. It is configured. In the present embodiment, the earth discharging device 83 is an earth pressure type or mud earth pressure shield, and thus a screw conveyor is used. However, an muddy water type shield uses a feed mud pipe.

  When the child shield 60 shown in FIG. 5 is started, a cylindrical extended rear cylinder 51 having the same diameter as the rear cylinder 50 is joined to the rear cylinder 50 by welding or the like. Erector 52 is provided. The erector 52 includes a swivel ring 54 that is rotatably supported by a support roller 53, and a grip portion 55 that is attached to the swivel ring 54 and is movable in the radial direction and the axial direction of the extended rear barrel 51. The child shield segment 56 is gripped. Further, a tail seal 57 is provided on the inner peripheral surface of the tail portion of the extended rear barrel 51 so as to contact the outer peripheral surface of the existing segment 56. A plurality of child shield shield jacks 58 are attached to the inner peripheral surface of the rear barrel 50 at intervals in the circumferential direction for taking the reaction force of the existing segments 56 and moving the child shield 60 forward.

  The middle folding mechanism 70 that connects the front cylinder 40 and the rear cylinder 50 is inserted into the concave spherical surface portion 71 provided on the rear inner peripheral surface of the front cylinder 40 and the rear inner peripheral surface of the front cylinder 40. It consists of a convex spherical surface portion 72 provided on the front outer peripheral surface of the rear barrel 50. The concave spherical portion 71 and the convex spherical portion 72 are engaged to constitute a spherical bearing, and a ring-shaped seal 73 is provided on the front and back thereof. In the present embodiment, the center of curvature radius (center of center bending) between the concave spherical surface portion 71 and the convex spherical surface portion 72 is set at a portion inside the curve of the center bending mechanism 70 as shown in FIG. May be set at the center of the child shield 60 in the radial direction (X-fold). Further, the middle folding mechanism 70 is not limited to a spherical bearing, and may be a middle folding pin that connects the front cylinder 40 and the rear cylinder 50 so that they can be bent.

  The front cylinder 40 and the rear cylinder 50 are connected via a bent jack 74. The middle folding jack 74 has one end connected to a bracket provided on the inner peripheral surface of the front barrel 40 and the other end connected to a bracket provided on the inner peripheral surface of the rear barrel 50, as shown in FIG. A plurality of them are arranged at intervals in the circumferential direction of the front barrel 40. The middle-folded jack 74 not only bends the front trunk 40 and the rear trunk 50 when digging as the child shield 60 but also the front trunk 10 and the rear trunk 20 when digging as the parent shield 30 as will be described later. Therefore, the number and the capacity per one are set so that the bending force corresponding to the force required when the parent shield 30 is bent can be exhibited.

  Next, the parent shield 30 will be described.

  As shown in FIG. 1, the parent shield 30 is fitted on the outer periphery of the front barrel 40 of the child shield 60 so that the front barrel 10 of the parent shield 30 can be connected and disconnected by the front barrel fixing device 11. The rear body 20 of the parent shield 30 is fitted on the outer periphery of the body 50 by the rear body fixing device 21 so as to be detachable. Further, a parent shield cutter 90 is detachably attached to the child shield cutter 80, which will be described later.

  The front cylinder 10 of the parent shield 30 is formed by an inner cylinder 12 formed to have an inner diameter that is slidably fitted to the front cylinder 40 of the child shield 60, and a larger diameter than the inner cylinder 12 by a parent shield cutter 90. The outer cylinder 13 formed in accordance with the diameter of the tunnel to be excavated, the ring plate-shaped rear lid 14 covering the openings at the rear ends of the inner cylinder 12 and the outer cylinder 13, and the front ends of the inner cylinder 12 and the outer cylinder 13 A ring plate-shaped front lid 15 that covers the opening of the ring plate, and a ring plate-shaped reinforcing plate 16 disposed between the front lid 15 and the rear lid 14.

  In this embodiment, the front trunk fixing device 11 is screwed into the nut 17 fixed to the inner cylinder 12 of the main shield front cylinder 10, the nut 18 fixed to the sub shield front cylinder 40, and the nuts 17 and 18. The screw shield 19 is screwed into the parent shield side nut 17 by fixing the screw rod 19 from the child shield side nut 18 to fix the child shield front barrel 40 and the parent shield front barrel 10, and the screw rod 19 is rotated in the reverse direction. By separating from the shield side nut 17, the parent shield front cylinder 10 is separated from the child shield front cylinder 40. A plurality of front trunk fixing devices 11 are arranged at intervals in the circumferential direction. The front trunk fixing device 11 is not limited to the above configuration, and may be configured by welding, pins, or the like. When welding is performed, the engagement is released by cutting the welded portion.

  As shown in FIG. 1, the main shield rear cylinder 20 includes an inner cylinder 22 fixed to the child shield rear cylinder 50 by a rear cylinder fixing device 21 so as to be able to be connected and disconnected, and an outer cylinder 23 having a larger diameter than the inner cylinder 22. And a ring-plate-like front lid 24 that covers the openings at the front ends of the inner cylinder 22 and the outer cylinder 23. Since the rear trunk fixing device 21 has the same configuration as the front trunk fixing device 11, the description thereof is omitted.

  The inner cylinder 22 is larger in diameter than the child shield rear cylinder 50, and then extends forward from the radially outer position of the cylinder 50 so as to overlap the outer circumferential surface of the child shield front cylinder 40 in the front-rear direction. The outer periphery of the front barrel 40 is formed to be spaced apart from the outer periphery in the radial direction by a predetermined distance L1. This predetermined interval L1 indicates that when the parent shield 30 bends as shown in FIG. 4, the front inner peripheral portion 25 of the rear cylinder 20 inside the curve of the parent shield 30 interferes with the outer peripheral surface of the child shield front cylinder 40. It is provided in order to ensure a predetermined bend angle while preventing.

  Returning to FIG. 1, the outer cylinder 23 of the rear barrel 20 has the same diameter as the outer diameter of the front portion 231 formed to have a predetermined length L2 smaller than the outer diameter of the parent shield front barrel 10 and the parent shield front barrel 10. And a tapered portion 233 that smoothly connects the front portion 231 and the rear portion 232. When the parent shield 30 is bent as shown in FIG. 4, the predetermined length L <b> 2 is equal to that of the inner surface of the digging hole obtained by cutting the outer peripheral end 26 of the rear barrel 20 outside the curve of the parent shield 30 by the parent shield cutter 90. It is positioned inward and is set in order to prevent the tip outer peripheral portion 26 from interfering with the inner surface of the digging hole.

  The front part 231 and the tapered part 233 of the outer cylinder 23, the inner cylinder 22 and the front lid 24 constitute an extension part 27 of the rear cylinder 20. The extending portion 27 extends forward from a radially outer position of the child shield rear barrel 50 so as to overlap with the outer circumferential surface of the child shield front barrel 40 in the front-rear direction, and the outer circumferential surface of the child shield front barrel 40. Is formed in a bag shape having a ring-shaped opening 271 on the rear side and spaced apart by a predetermined distance L1 radially outward.

  As shown in FIG. 3, a plurality of shield jacks 28 for a parent shield are provided in the extension portion 27 at intervals in the circumferential direction of the rear barrel 20. Specifically, as shown in FIG. 1, a bracket 29 formed in a ring plate shape is provided in the opening 271 of the extending portion 27 so as to cover the opening 271. A plurality of jack mounting holes are provided at intervals in the circumferential direction, and a parent shield shield jack 28 is mounted in these jack mounting holes.

  As shown in FIG. 1, a parent shield erector 201 is provided inside the rear portion of the rear barrel 20. The erector 201 includes a swiveling ring 203 that is rotatably supported by a support roller 202, and a grip portion 204 that is attached to the swivel ring 203 and is movable in the radial direction and the axial direction of the rear barrel 20. The parent shield segment 205 is gripped. In addition, a tail seal 206 is provided on the inner peripheral surface of the tail portion of the rear barrel 20 so as to be in contact with the outer peripheral surface of the existing segment 205. A ring-shaped seal / spacer 209 is interposed between the child shield rear cylinder 50 and the parent shield rear cylinder 20.

  The front torso 10 and the back torso 20 are formed so as to cover the gap 207 to the side ground between the front torso 10 and the back torso 20 so as to be bridged between them. A seal 208 that allows bending with the body 20 is provided. The seal 208 is formed in a bellows cylinder shape from a flexible material such as resin or hard rubber, the front end is fixed along the circumferential direction of the rear end of the front barrel 10 along the circumferential direction, and the rear end is the outer circumferential surface of the rear barrel 20. The base shield 30 is freely deformed so as not to inhibit the bending when the parent shield 30 is bent as shown in FIG. Note that the seal 208 is not limited to this configuration, and may be omitted.

  Next, the cutter will be described.

  As shown in FIG. 1, the cutter 100 includes a child shield cutter 80 connected to a rotating plate 84 that can rotate with respect to the partition wall 41, and a parent shield cutter that is detachably attached to the outer periphery of the child shield cutter 80. A cutter 90.

  As shown in FIG. 2, the child shield cutter 80 includes a cutter spoke 801 arranged radially from the center of rotation, and a ring 802 connecting the outer peripheral ends of the cutter spokes 801, and the cutter spoke 801 has a bit. 803 is attached. As shown in FIG. 1, the diameter of the outer peripheral end of the cutter pork 801 (the outer diameter of the ring 802) matches the outer diameter R <b> 1 of the front body 40 of the child shield 60. The child shield cutter 80 is not limited to the spoke type described above, and may be a face plate type.

  Returning to FIG. 2, the parent shield cutter 90 includes a cutter pork 901 extending radially outward from the outer peripheral end of the cutter pork 801 of the child shield cutter 80 with a predetermined interval L3, and the cutter pork 901. The inner peripheral ring 902 that connects the inner peripheral ends of the two and the outer peripheral ring 903 that connects the outer peripheral ends of the cut-out spokes 901, and a bit 904 is attached to the cut-out spoke 901. As shown in FIG. 1, the inner peripheral end diameter R2 of the cutter pork 901 (the inner diameter of the inner peripheral ring 902) is larger than the outer diameter R1 of the child shield front body 40 by the predetermined interval L3. When 60 starts from the parent shield 30 and the child shield front cylinder 40 passes through the inner ring 902 of the parent shield cutter 90, it is prevented from being caught. The parent shield cutter 90 is not limited to the spoke type described above, and may be a face plate type.

  As shown in FIG. 1, an engagement / disengagement that engages and disengages from the parent shield cutter 90 by projecting radially outward from the outer peripheral end of the cutter pork 801 inside the cutter spoke 801 of the child shield cutter 80. A device 804 is provided. The engagement / disengagement device 804 includes a jack 805 housed inside the cutter pork 801, a bottomed cylindrical insertion / extraction member 806 connected to a rod of the jack 805, and a parent shield so that the insertion / extraction member 806 is inserted / extracted. The insertion hole 807 is formed in the cutter pork 901 of the cutter 90. According to this engagement / disengagement device 804, by inserting the rod of the jack 805, the insertion / extraction member 806 is inserted into the insertion / extraction hole 807 as shown in FIG. 1, and the parent shield cutter 90 is fixed to the child shield cutter 80, By pulling the rod of the jack 805, the insertion / extraction member 806 is extracted from the insertion / extraction hole 807 as shown in FIG. 5, and the parent shield cutter 90 is separated from the child shield cutter 80.

  A copy cutter jack 808 is accommodated in the insertion / extraction member 806. The copy cutter jack 808 has a rod fixed to the bottom plate of the bottomed cylindrical insertion / extraction member 807, a cylinder slidably mounted on the rod, and a copy cutter 809 provided on the head of the cylinder. Then, the copy cutter 809 is made to project radially outward from the outer peripheral end of the parent shield cutter 90 in FIG. 1 or the outer shield end of the child shield cutter 80 in FIG. Excavate the inside of the curve when digging.

  In FIG. 2, the cutter pork 901 of the parent shield cutter 90 without the copy cutter 809 and the cutter pork 801 of the child shield cutter 80 are disengaged by another engaging / disengaging device. It has become. Another engagement / disengagement device includes a jack housed in the cutter pork 801 of the child shield cutter 80 and an insertion / extraction hole formed in the cutter pork 901 of the parent shield cutter 90 so that the rod of the jack can be inserted / removed. It consists of.

  The operation of the present embodiment having the above configuration will be described.

  When excavating as the parent shield 30, as shown in FIG. 1, the parent shield cutter 90 is attached to the outer periphery of the child shield cutter 80 by the engagement / disengagement device 804 in advance in the start shaft or the like. The front shield 10 is attached to the outer periphery by the front barrel fixing device 11, the rear shield 20 is attached to the outer periphery of the rear shield 50 by the rear barrel fixing device 21, and the extended portion 27 of the rear barrel 20 is shielded. The jack 28 is attached, and the erector 201 is attached to the inside of the rear trunk 20. At this time, the extended rear barrel 51, the child shield erector 52, and the child shield shield jack 58 shown in FIG. 5 are obstructed in assembling the segment 205 by the parent shield erector 201. It is. By tunneling this parent shield 30, a large-diameter tunnel can be constructed.

  When the parent shield 30 digs up the curve, as shown in FIG. 4, the front trunk 10 and the rear trunk 20 of the parent shield 30 are provided inside the child shield 60 by extending the middle folding jack 74 outside the curve. Further, it is bent by the middle folding mechanism 70. In this way, since the middle folding mechanism 70 of the child shield 60 is also used for bending the parent shield 30, a middle folding mechanism for the parent shield is provided between the front trunk 10 and the rear trunk 20 of the parent shield 30. There is no need to provide it. Since the middle folding mechanism 70 has to bendably connect the front cylinder 40 and the rear cylinder 50 and to stop water between the front cylinder 40 and the rear cylinder 50, it is necessary to manufacture the folding mechanism 70 with high accuracy by cutting or the like. However, since the expensive middle folding mechanism 70 is shared by the parent shield 30 and the child shield 60, the one for the parent shield 30 can be omitted, leading to a large cost reduction.

  Further, since the shield jack 28 for the parent shield is accommodated in the extending portion 27 arranged on the outer side in the radial direction so as to surround the middle folding mechanism 70 shared by the parent shield 30 and the child shield 60, Since the mechanism 70 and the shield jack 28 are arranged in parallel, the length of the parent shield 30 can be shortened, which is advantageous in curve construction. In other words, if the extension jack 27 is omitted and the shield jack 28 is disposed rearward in the axial direction of the center folding mechanism 70 (counter face), the center folding mechanism 70 and the shield jack 28 are arranged in series. When the length of the shield 30 becomes long and curve construction is disadvantageous, in this embodiment, the extended portion 27 extended forward so as to wrap around the front barrel 40 of the child shield 60 is provided on the rear barrel 20. By forming and accommodating the shield jack 28 inside the extension portion 27, the shield jack 28 and the middle folding mechanism 70 are juxtaposed to shorten the length of the main shield 30.

  In the structure in which the extension 27 of the rear barrel 20 of the parent shield 30 is wrapped on the front barrel 40 of the child shield 60 in this way to shorten the length of the parent shield 30, When the trunk 10 and the rear trunk 20 are bent using the middle folding mechanism 70 and the middle folding jack 74, as shown in FIG. 4, the inside of the tip of the extending portion 27 of the parent shield rear trunk 20 is formed inside the curve. Where the peripheral portion 25 and the outer peripheral surface of the child shield front barrel 40 can interfere with each other, the above-described predetermined distance is provided between the inner tube 22 of the extension portion 27 of the parent shield rear barrel 20 and the outer peripheral surface of the child shield front barrel 40. By providing L1, the said interference is avoided and the predetermined middle bend angle is ensured. Further, on the outside of the curve, the outer peripheral end 26 of the extended portion 27 of the parent shield rear cylinder 20 can interfere with the inner surface of the digging hole formed by cutting with the parent shield cutter 90. By forming the front portion 231 of the outer cylinder 23 of the projecting portion 27 smaller in diameter than the outer diameter of the parent shield front barrel 10 by a predetermined length L2, the above-described interference is avoided and a predetermined middle bending angle is set. Secured.

  Further, since the gap 207 between the front trunk 10 and the rear trunk 20 of the parent shield 30 is covered with the seal 208 and sealed from the side ground, the extended portion 27 of the parent shield rear trunk 20 and the child shield It is prevented that earth and sand are caught between the front body 40 and the bending is inhibited.

  Next, the procedure for starting the child shield 60 from the parent shield 30 shown in FIG. 1 will be described with reference to FIG.

  As shown in FIGS. 1 and 5, the parent shield rear cylinder 20 is fixed to the existing segment 205 by a bracket 210 to prevent the parent shield 30 from retreating, and the parent shield shield jack 28 and the erector 201 are removed and collected. However, since the shield jack 28 is located radially outward of the front barrel 40 and the rear barrel 50 of the child shield 30, it does not interfere with the start of the child shield 60 even if left without being removed.

  An extended rear cylinder 51 is added to the rear end of the child shield rear cylinder 50, and a child shield erector 52 is installed inside the extended rear cylinder 51. The reaction force receiving block 211 is attached to the existing segment 201 in a ring shape, and the child shield segment 26 is brought into contact with the block 211 to be assembled in a ring shape by the erector 52 or the like. A shield jack 58 for a child shield is attached to the rear shield 50 of the child shield.

  The screw rod 19 of the front trunk fixing device 11 is loosened to separate the parent shield front trunk 10 from the child shield front trunk 40, and the screw rod of the rear trunk fixing device 21 is loosened to separate the parent shield rear trunk 20 from the child shield rear trunk 50. The screw rod 19 serves as a water stopper for the screw hole of the nut 18. Further, the rod of the jack 805 in the child shield cutter 80 is immersed, the insertion / extraction member 806 is pulled out from the insertion / extraction hole 807, and the parent shield cutter 90 is separated from the child shield cutter 80. As a result, as shown in FIG. 5, the child shield 60 ready for start-up is housed inside the parent shield 30.

  Thereafter, the child shield cutter 80 is rotated, the child shield shield jack 58 is extended, the reaction force is applied to the segment 56, and the child shield 60 is started from the parent shield 30. At this time, the inner diameter of the hole of the parent shield cutter 90 (the inner diameter R2 of the inner ring 902) through which the child shield 60 passes is the outer diameter of the child shield cutter 80, that is, the front cylinder 40 and the rear cylinder 50 of the same diameter. Therefore, the child shield 60 can start smoothly through the hole of the parent shield cutter 90. Specifically, since the parent shield cutter 90 receives earth pressure from the front face of the face, it is not dragged forward by the child shield 60 and the parent shield front trunk 10 is caught by the parent shield cutter 90 in a stopped state. Therefore, even if dragged by the child shield 60, it does not move forward.

  The child shield 60 after the start from the parent shield 30 is bent halfway by the middle-folding jack 74 and the middle-folding mechanism 70, and the copy cutter jack 808 is appropriately expanded and contracted when the middle-folding digging, that is, the curve digging. By cutting the cutter 809 from the outer peripheral end of the child shield cutter 80 as appropriate, the ground inside the curve is dug.

  A modified embodiment of the present invention is shown in FIG.

  The center-foldable parent-child shield 1 according to this modified embodiment is only the point that an intermediate jack 220 is additionally provided between the front body 10 and the rear body 20 of the parent shield 30 according to the previous embodiment. Unlike the embodiment, the rest of the configuration is the same, so the same components are denoted by the same reference numerals and description thereof is omitted.

  A plurality of the intermediate folding jacks 220 are arranged at intervals in the circumferential direction. When the front trunk 10 and the rear trunk 20 of the parent shield 30 are bent, only the middle folding jack 74 in the child shield 60 is provided. Then, it is provided to compensate for the bending force (breaking moment) that tends to be insufficient. Since the added middle folding jack 220 is arranged at a position where the distance from the middle folding center (the length of the arm of the middle folding moment) is longer than the middle folding jack 74 in the child shield 60, the parent shielding is efficiently performed. 30 middle bending moments can be compensated.

  Embodiments of the present invention are not limited to the above-described embodiments. For example, the shield jack 28 of the parent shield 30 may be arranged with its position shifted rearward in the shield axial direction with respect to the middle folding mechanism 70 provided in the child shield 60.

It is a sectional side view when making the folding type parent-child shield which concerns on one Embodiment of this invention function as a parent shield. It is an II-II line arrow figure of FIG. It is the III-III sectional view taken on the line of FIG. FIG. 2 is a plan sectional view when the parent shield of FIG. 1 is bent. It is a sectional side view just before starting a child shield from the parent shield of FIG. It is plane sectional drawing which shows the deformation | transformation embodiment of a middle folding type parent-child shield.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Folding-type parent-child shield 10 Front trunk 20 Rear trunk 27 Extension part 28 Parent shield shield jack 30 Parent shield 40 Front trunk 50 Rear trunk 60 Sub shield 70 Middle folding mechanism 207 Clearance 208 Seal 220 Middle folding jack

Claims (3)

From the parent shield that can bend the front and rear torso, the child shield that can be bent from the front and rear
A front torso of the parent shield is fitted on the outer periphery of the front torso of the child shield by a front torso fixing device, and a rear torso fixing device is attached to the outer periphery of the rear torso of the child shield. connection separation capable fitted over, and connected through a center-folding jack with flexibly connected through the center bending mechanism and a front cylinder and a rear cylinder of said child shielded by,
The child shield's middle folding mechanism and middle jack are connected to the front and rear trunks of the parent shield connected to the front and rear trunks of the child shield via a front trunk fixing device and a rear trunk fixing device. Via a bendable connection via
Sharing the middle folding mechanism and the middle folding jack for bending the front and rear torso of the parent shield,
The rear body of the parent shield has an extension part that extends forward and overlaps with the outer circumferential surface of the front body of the child shield in the front-rear direction and is spaced radially outward from the outer circumferential surface; A folding type parent-child shield comprising the extension jack provided with a shield jack for the parent shield. The middle-folding type parent-child shield according to claim 1 , wherein the extension portion has a smaller diameter than the outer diameter of the front body of the parent shield. The middle-folding type parent-child shield according to claim 1 or 2, wherein the extension portion is formed in a bag shape having a ring-shaped opening at the rear, and a shield jack of a parent shield is provided therein.

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