CN209892058U

CN209892058U - Safety door sill for closing door

Info

Publication number: CN209892058U
Application number: CN201821361546.XU
Authority: CN
Inventors: 陈华
Original assignee: Zhejiang Li Tong Household Co Ltd
Current assignee: Hangzhou Xuli Holding Group Co ltd
Priority date: 2018-08-23
Filing date: 2018-08-23
Publication date: 2020-01-03
Anticipated expiration: 2028-08-23

Abstract

The utility model discloses a safety door fence closes door. The door-closing safety door sill comprises a hinge mechanism and a locking mechanism, wherein the hinge mechanism comprises a rotating shaft hinge piece and a rebounding hinge piece; the locking mechanism comprises an upper locking piece, a lower locking piece and a lifting piece connecting the upper locking piece and the lower locking piece. The upper locking assembly comprises an upper lock tongue, an upper receiving box and a push button arranged on the upper lock tongue in a sliding manner; the lower locking element comprises a lower lock tongue and a lower receiving box; the lifting piece comprises a lifting handle, a lifting ball body and a lifting line connecting the lifting handle and the lifting ball body. The utility model discloses an automatic opening direction of interior door of safety door fence of closing door is unrestricted, can two-wayly open the door, can automatic back door, convenient to use after taking out again.

Description

Safety door sill for closing door

Technical Field

The utility model belongs to indoor children or pet use the door fence, concretely relates to safety door fence closes door.

Background

The prior door fence generally comprises a door frame and a door fence, wherein the door fence is hinged to one side of the door frame, a door frame lock is arranged on the other side of the door frame, a door fence lock matched with the door frame lock is arranged on the other side of the door fence, and the door fence is manually locked on the door frame lock through the door fence lock, so that the door fence and the door frame are locked. Such a structure requires manual operation for locking, and does not perform automatic locking even when the door frame lock and the doorsill lock are close to each other, but requires manual locking. This structure presents risks in the range of child activities: after the door fence is opened, adults can pass through the door fence and enter places with certain dangers (such as a kitchen and the like) by carelessly and manually locking the door fence and the door frame, so that children are injured.

SUMMERY OF THE UTILITY MODEL

In view of the above, the present invention is to provide a door-closing safety door fence, which has two-way door opening and automatic door returning functions.

In order to achieve the above object, the present invention provides a door-closing safety door fence, which includes a door frame and an inner door, wherein one side of the inner door is hinged to the door frame through a hinge mechanism, the other side of the inner door is locked to the door frame through a locking mechanism, and the hinge mechanism includes a rotating shaft hinge member and a resilient hinge member; the locking mechanism comprises an upper locking piece, a lower locking piece and a lifting piece connecting the upper locking piece and the lower locking piece.

The upper locking part comprises a handle box arranged on the inner door and an upper receiving box arranged on the door frame, an upper lock tongue is arranged in the handle box, a first cavity and a second cavity are formed in the upper lock tongue, a push button capable of reciprocating is arranged in the second cavity, the top of the push button protrudes out of the handle box, and the upper lock tongue and the push button are both connected with a reset spring for resetting; the lower locking piece comprises a mounting box arranged on the inner door and a lower receiving box arranged on the door frame, a lower lock tongue is arranged in the mounting box, the tail end of the lower lock tongue is provided with an inclined plane, the inclined plane is hollow, an opening communicated with the inner hollow is formed in the inclined plane, and the lower lock tongue is connected with a reset spring for resetting; the lifting piece comprises a lifting handle, a lifting ball body and a lifting wire connecting the lifting handle and the lifting ball body, the lifting ball body is accommodated in the hollow inner portion of the inclined plane, the lifting wire penetrates through the opening to be connected with the lifting ball body, a limiting block used for limiting the movement of the lifting handle and a driving block used for driving the upper lock tongue to move in the direction of separating from the upper receiving box through inserting the first cavity are arranged on the lifting handle, and the limiting block realizes locking and unlocking through the reciprocating motion of the push button.

Preferably, the inner wall of the handle box is provided with a limiting protrusion, and two sides of the lifting handle are provided with limiting grooves for inserting the limiting protrusion to limit the movement direction of the lifting handle.

Preferably, a movable block is arranged in the lifting handle, and the lifting wire penetrates through the lifting handle and is fixed on the movable block.

Preferably, a return spring is arranged on the lifting handle.

Preferably, a first sliding groove is formed in the inner wall of the handle box, and a first sliding block for enabling the upper lock tongue to reciprocate in the sliding groove is arranged on the outer wall of the upper lock tongue.

Preferably, a second sliding groove is formed in the inner wall of the handle box, and a second sliding block for enabling the push button to reciprocate in the sliding groove is arranged on the push button.

Preferably, the lifting handle is sleeved on a circular tube of the inner door, and the lifting wire penetrates through the circular tube and is connected with the lifting ball body.

Preferably, the rebounding hinge element comprises an inner door rotating shaft arranged on the inner door, a rotating shaft base fixedly arranged on the door frame and a bidirectional connecting piece which is connected with the inner door rotating shaft and the rotating shaft base and used for realizing bidirectional door opening, the bidirectional connecting piece comprises a rotating shaft iron piece, an upper rotor, an upper rotating shaft cover, a bidirectional torsion spring, a lower rotor and a lower rotating shaft cover, the upper rotor, the upper rotating shaft cover, the lower rotating shaft cover, the bidirectional torsion spring, the lower rotor and the lower rotating shaft cover are sequentially sleeved on the rotating shaft iron piece from top to bottom, the upper rotating shaft cover and the lower rotating shaft cover are accommodated in the rotating shaft base, stop bodies are arranged on the; the upper rotating shaft cover is provided with an upper accommodating cavity for accommodating the upper rotor and a lower accommodating cavity for accommodating the bidirectional torsion spring, a stopping part for stopping the upper rotor is arranged in the upper accommodating cavity, and a clamping part for clamping the bidirectional torsion spring and a central shaft are arranged in the lower accommodating cavity; the lower shaft cover is provided with a containing space, an upper containing cavity and a containing space of the bidirectional torsion spring are arranged in the lower containing cavity of the lower rotor, a clamping portion of the bidirectional torsion spring is used for clamping the upper containing cavity, a shaft hole of the central shaft is formed in the upper containing cavity, and a stopping portion used for stopping the lower rotor is arranged in the lower containing cavity.

Preferably, the rotating shaft iron piece is provided with edges, and the shape of the through holes of the upper rotor and the lower rotor is consistent with the shape of the cross section of the rotating shaft iron piece, so that a clamping structure is formed to realize linkage of the rotating shaft iron piece, the upper rotor and the lower rotor.

Preferably, a through hole is formed in the inner door rotating shaft, the rotating shaft iron piece is inserted into the through hole, and the two-way connecting piece is fixed through a nut.

When the door of the safety door fence for closing the door is opened, the push button is firstly opened, the lifting handle is limited by unlocking, the lifting handle is lifted upwards, the driving block drives the upper spring bolt to move towards the direction away from the upper receiving box to release the upper receiving box, and the lifting wire drives the lower spring bolt to move towards the direction away from the lower receiving box to release the lower receiving box, so that synchronous unlocking is realized; the opened inner door realizes bidirectional door opening and automatic door closing by the rebounding hinge piece. The utility model discloses a direction of opening of the interior door of the safety door fence that closes the door is unrestricted, can two-wayly open the door, can automatic back door, convenient to use after taking out again.

Drawings

Fig. 1 is a structural diagram of a door-closing safety fence according to an embodiment of the present invention;

fig. 2 is a structural view of a locking mechanism of the door closing safety fence according to the embodiment of the present invention;

fig. 3 is an exploded view of the resilient hinge of the door closer security fence of the embodiment of the present invention;

fig. 4 is a structural diagram of a lower locking member of the door-closing safety fence according to the embodiment of the present invention.

Wherein, 100-door frame, 200-inner door, 300-rotating shaft hinge element, 400-rebound hinge element, 410-inner door rotating shaft, 420-rotating shaft base, 421-gear, 430-bidirectional connecting element, 431-rotating shaft iron element, 432-upper rotor, 433-upper rotating shaft cover, 4331-stopping part, 434-bidirectional torsion spring, 435-lower rotor, 436-lower rotating shaft cover, 4361-clamping part, 4362-shaft hole, 437-stopping body, 500-upper locking element, 510-handle box, 520-upper receiving box, 530-upper locking bolt, 531-first cavity, 532-second cavity, 533-first sliding block, 540-push-button, 541-second sliding block, 550-return spring, 600-lower locking element, 610-mounting box, 620-lower receiving box, 630-lower lock tongue, 631-inclined plane, 632-opening hole, 700-lifting piece, 710-lifting handle, 711-limiting block, 712-driving block, 713-limiting groove, 714-movable block, 720-lifting ball body and 730-lifting wire.

Detailed Description

The following are specific embodiments of the present invention and the accompanying drawings are used to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

Referring to fig. 1, the door-closing safety door fence of the present invention includes a door frame 100 and an inner door 200, wherein one side of the inner door 200 is hinged to the door frame 100 through a hinge mechanism, the other side of the inner door 200 is locked to the door frame 100 through a locking mechanism, and the hinge mechanism includes a rotating shaft hinge 300 and a resilient hinge 400; the locking mechanism includes an upper locking element 500, a lower locking element 600, and a pull-up element 700 connecting the upper locking element 500 and the lower locking element 600. The rotating shaft hinge 300 is a common hinge of a shaft and a hole, and the rebound hinge 400 realizes bidirectional door opening and automatic closing of the door sill; the lifting member 700 ensures the synchronous opening of the upper locking member 500 and the lower locking member 600, and prevents the damage of the lower locking member 600 caused by the sliding of the door sill when only the upper locking member 500 is opened. In addition, installation parts for installing the door-closing safety fence are provided at both sides of the door frame 100, and the installation of the door fence can be achieved by screwing the installation parts to the wall body. Different door frame 100 sizes may be designed as desired to meet the installation needs of the user and the different needs of the viewing area within the door sill.

Referring to fig. 2, the upper locking member 500 of the locking mechanism of the present invention includes a handle box 510 disposed on the inner door 200 and an upper receiving box 520 disposed on the door frame 100. The handle box 510 is provided with an upper latch 530, the inner wall of the handle box 510 is provided with a first sliding groove, the outer wall of the upper latch 530 is provided with a first sliding block 533 for the upper latch 530 to reciprocate in the sliding groove, so that the upper latch 530 slides in the handle box 510, and the upper receiving box 520 is removed from or inserted into the handle box 510 to unlock and lock the upper locking part 500. The upper bolt 530 is provided with a first cavity 531 and a second cavity 532, a push button 540 capable of reciprocating is arranged in the second cavity 532, the inner wall of the handle box 510 is provided with a second sliding groove, the push button 540 is provided with a second sliding block 541 for the push button 540 to reciprocate in the sliding groove, and the top of the push button 540 protrudes out of the handle box 510. The upper latch 530 and the push button 540 are both connected with a return spring 550 for returning, and the return spring 550 is fixed in a spring receiving groove formed in the handle case 510.

Referring to fig. 2 again, the lower locking member 600 of the present invention includes a mounting box 610 provided on the inner door 200 and a lower receiving box 620 provided on the door frame 100. A lower bolt 630 is arranged in the mounting box 610, and an accommodating box for accommodating the lower bolt 630 is arranged in the mounting box 610. The sliding groove is formed on the bottom surface of the side of the accommodating box, the lower latch 630 is provided with the bulge, and the bulge is inserted into the sliding groove, so that the structure limits the lower latch 630 to move linearly, and simultaneously stops the lower latch 630 to prevent the lower latch 630 from excessively protruding out of the mounting box 610. The lower latch 630 has a slope 631, the slope 631 is hollow, and the slope 631 is provided with an opening 632 communicating with the hollow inside. In addition, a return spring 550 for return is connected to the lower latch 630. One end of the return spring 550 is fixed to the lower latch 630 and the other end is fixed to the inner wall of the receiving box. The return spring 550 may be in a natural state or in a compressed state when the lower latch 630 is in a locked state. The mounting box 610 is provided with a mounting screw hole and is mounted on the inner door 200 through a bolt, so that the mounting and dismounting are convenient.

Referring to fig. 4, the pulling member 700 of the present invention includes a pulling handle 710, a pulling ball 720, and a pulling wire 730 connecting the pulling handle and the pulling ball 720. The lifting handle 710 is sleeved on the circular tube of the inner door 200, and the lifting wire 730 penetrates through the circular tube to be connected with the lifting ball 720. The lifting ball 720 is accommodated in the hollow inside of the inclined surface 631, the lifting wire 730 passes through the opening 632 to be connected with the lifting ball 720, and the other end of the lifting wire 730 passes through the lifting handle 710 to be fixed on the movable block 714 in the lifting handle 710. The lifting handle 710 is provided with a limiting block 711 for limiting the movement of the lifting handle 710 and a driving block 712 for driving the upper latch 530 to move in the direction of pulling out the upper receiving box 520 by being inserted into the first cavity 531, and the limiting block 711 realizes locking and unlocking by the reciprocating motion of the push button 540. The driving block 712 is a ramp and the direction of the ramp is away from the upper receiving box 520. When the push button 540 is in a closed state, the push button abuts against the limiting block 711 of the lifting handle 710 to limit the upward movement of the lifting handle 710; when the push button 540 is in an open state, the position above the limit block 711 is vacant, the lifting handle 710 can move upwards as a whole, the driving block 712 contacts the side wall of the second cavity 532 along with the upward movement of the lifting handle 710, the upper locking tongue 530 is driven to move in the direction away from the upper receiving box 520, and finally the upper receiving box 520 is disengaged, and meanwhile, the lifting ball 720 drives the lower locking tongue 630 to move in the direction away from the lower receiving box 620 under the driving of the lifting wire 730, and finally the lower receiving box 620 is disengaged.

In order to ensure the vertical upward movement of the carrying handle 710, a limiting protrusion is provided on the inner wall of the handle case 510, and limiting grooves 713 for inserting the limiting protrusion to limit the moving direction of the carrying handle 710 are provided at both sides of the carrying handle 710. The upper latch 530 moves toward the upper receiving case 520 by the elastic force of the return spring 550 to drive the driving body to move downward, and the lower latch 630 moves toward the lower latch 630 by the elastic force of the return spring 550 to drive the lifting ball 720 to move downward, and the lifting handle 710 returns to its original position by the weight of the lifting handle 710. In order to quickly return the carrying handle 710, a return spring 550 is coupled to the carrying handle 710, and the return spring 550 is installed in a spring receiving groove provided in the handle case 510.

Referring to fig. 3, the rebounding hinge assembly 400 of the present invention includes an inner door hinge 410 disposed on the inner door 200, a hinge base 420 fixedly disposed on the door frame 100, and a bidirectional connecting member 430 for connecting the inner door hinge 410 and the hinge base 420 and used for realizing bidirectional opening of the door, wherein the bidirectional connecting member 430 includes a hinge iron 431, and an upper rotor 432, an upper hinge cover 433, a bidirectional torsion spring 434, a lower rotor 435, a lower hinge cover 436 sequentially sleeved on the hinge iron 431 from top to bottom, and the upper hinge cover 433 and the lower hinge cover 436 are accommodated in the hinge base 420. The inner door hinge 410 is provided with a through hole, and the hinge iron 431 is inserted into the through hole, so that the two-way connection member 430 is fixed by a nut. The rotating shaft iron piece 431 is provided with edges, and the shapes of through holes of the upper rotor 432 and the lower rotor 435 are consistent with the cross section shape of the rotating shaft iron piece 431, so that a clamping structure is formed to realize linkage of the rotating shaft iron piece 431, the upper rotor 432 and the lower rotor 435. The side walls of the upper rotating shaft cover 433 and the lower rotating shaft cover 436 are both provided with a stopping body 437, and a gear 421 for stopping the stopping body 437 is arranged in the rotating shaft base 420; the upper rotating shaft cover 433 is provided with an upper accommodating cavity for accommodating the upper rotor 432 and a lower accommodating cavity for accommodating the bidirectional torsion spring 434, a stopping part 4331 for stopping the upper rotor 432 is arranged in the upper accommodating cavity, and a clamping part 4361 for clamping the bidirectional torsion spring 434 is arranged in the lower accommodating cavity; the lower spindle cover 436 is provided with an upper accommodating chamber for accommodating the bidirectional torsion spring 434 and a lower accommodating chamber for accommodating the lower rotor 435, the upper accommodating chamber is provided with a clamping portion 4361 for clamping the bidirectional torsion spring 434 and a spindle hole 4362 for sleeving the bidirectional torsion spring 434, and the lower accommodating chamber is provided with a stopping portion 4331 for stopping the lower rotor 435.

When the inner door 200 is opened, the inner door rotating shaft 410 rotates, the rotating shaft iron part 431, the upper rotor 432 and the lower rotor 435 are linked together, the upper rotor 432 is abutted against the stop body 437 in the upper rotor cover 433 to drive the upper rotor cover 433 to rotate, one end of the two-way spring clamped with the upper rotor cover 433 moves, and reaction force is generated to realize return; the lower rotary shaft cover 436 is clamped at the gear 421 of the rotary shaft base 420 by means of the upper stop body 437, so that the lower rotary shaft cover 436 and the bidirectional torsion spring 434 are fixed in the door opening process, and at the moment, the lower rotor 435 rotates between the stop bodies 437 of the lower rotary shaft cover 436. When opening interior door 200 to another direction, go up pivot lid 433 and rely on its backstop body 437 card at the gear 421 of pivot base 420, guaranteed opening the door in-process and gone up pivot lid 433 and two-way torsional spring 434 fixed, the backstop body 437 butt in rotor 435 and the lower pivot lid 436 drives last pivot lid 433 and rotates down, and two-way spring is movable with one end of last pivot lid 433 block, produces reaction force and realizes the return. The upper and lower hooks of the bidirectional torsion spring 434 are just in the middle, so that the left and right forces are the same when the door sill is at rest, the door sill will always be kept in a closed state, and only when the door sill is opened, the bidirectional torsion spring 434 is compressed to generate a counterforce.

The utility model discloses a safe door fence of closing door opens the door when opening the door and pushes away the knob 540 at first, and the unblock is to carrying the restriction of carrying handle 710, will carry and draws handle 710 to mention upwards, and the drive block 712 drives upper lock tongue 530 to receive box 520 direction motion and throw off and accept box 520 on keeping away from, carries simultaneously to draw and draws line 730 to drive down lock tongue 630 to receive box 620 direction motion and throw off and accept box 620 down far away from, realizes synchronous unblock; the opened inner door 200 is bi-directionally opened and automatically closed by means of a resilient hinge 400. The utility model discloses a direction of opening of interior door 200 of safety door fence that closes door is unrestricted, can two-wayly open the door, can automatic back door, convenient to use after taking out again.

Although certain specific embodiments of the present invention have been described in detail by way of illustration, it will be understood by those skilled in the art that the foregoing examples are for purposes of illustration only and are not intended to limit the scope of the invention, which is to be construed as broadly as the present invention will suggest themselves to those skilled in the art to which the invention pertains and which is susceptible to various modifications or additions and similar arrangements to the specific embodiments described herein without departing from the scope of the invention as defined in the appended claims. It should be understood by those skilled in the art that any modifications, equivalent substitutions, improvements and the like made to the above embodiments according to the technical spirit of the present invention should be included in the scope of the present invention.

Claims

1. A door-closing safety door fence, comprising a door frame (100) and an inner door (200), wherein one side of the inner door (200) is hinged on the door frame (100) through a hinge mechanism, and the other side of the inner door (200) is locked on the door frame (100) through a locking mechanism, characterized in that: the hinge mechanism comprises a rotating shaft hinge (300) and a rebound hinge (400); the locking mechanism comprises an upper locking piece (500), a lower locking piece (600) and a lifting piece (700) connecting the upper locking piece (500) and the lower locking piece (600);

the upper locking part (500) comprises a handle box (510) arranged on the inner door (200) and an upper receiving box (520) arranged on the door frame (100), an upper locking bolt (530) is arranged in the handle box (510), a first cavity (531) and a second cavity (532) are arranged on the upper locking bolt (530), a push knob (540) capable of reciprocating is arranged in the second cavity (532), the top of the push knob (540) protrudes out of the handle box (510), and a return spring (550) for returning is connected to each of the upper locking bolt (530) and the push knob (540); the lower locking piece (600) comprises a mounting box (610) arranged on the inner door (200) and a lower receiving box (620) arranged on the door frame (100), a lower bolt (630) is arranged in the mounting box (610), the lower bolt (630) is provided with an inclined surface (631), the inclined surface (631) is hollow, an opening (632) communicated with the hollow inside is formed in the inclined surface (631), and the lower bolt (630) is connected with a return spring (550) for returning; the lifting piece (700) comprises a lifting handle (710), a lifting ball body (720) and a lifting line (730) connecting the lifting handle (710) and the lifting ball body (720), the lifting ball body (720) is accommodated in the hollow interior of the inclined surface (631), the lifting line (730) penetrates through the opening (632) to be connected with the lifting ball body (720), the lifting handle (710) is provided with a limiting block (711) used for limiting the movement of the lifting handle (710) and a driving block (712) which is inserted into the first cavity (531) to drive the upper lock tongue (530) to move towards the direction of being separated from the upper receiving box (520), and the limiting block (711) realizes locking and unlocking through the reciprocating movement of the push knob (540).

2. The door-closing safety fence according to claim 1, wherein: the inner wall of the handle box (510) is provided with a limiting bulge (511), and two sides of the lifting handle (710) are provided with limiting grooves (713) used for inserting the limiting bulge (511) to limit the movement direction of the lifting handle (710).

3. The door-closing safety fence according to claim 1, wherein: a movable block (714) is arranged in the lifting handle (710), and the lifting wire (730) penetrates through the lifting handle (710) and is fixed on the movable block (714).

4. The door-closing safety fence according to claim 1, wherein: the lifting handle (710) is provided with a return spring (550).

5. The door-closing safety fence according to claim 1, wherein: a first sliding groove (512) is formed in the inner wall of the handle box (510), and a first sliding block (533) for enabling the upper locking bolt (530) to reciprocate in the sliding groove is arranged on the outer wall of the upper locking bolt (530).

6. The door-closing safety fence according to claim 1, wherein: a second sliding groove (513) is formed in the inner wall of the handle box (510), and a second sliding block (541) for enabling the push button (540) to reciprocate in the sliding groove is arranged on the push button (540).

7. The door-closing safety fence according to claim 1, wherein: the lifting handle (710) is sleeved on a circular tube of the inner door (200), and the lifting wire (730) penetrates through the circular tube and is connected with the lifting ball body (720).

8. The door-closing safety fence according to claim 1, wherein: the rebounding hinge (400) comprises an inner door rotating shaft (410) arranged on the inner door (200), a rotating shaft base (420) fixedly arranged on the door frame (100) and a bidirectional connecting piece (430) which is used for connecting the inner door rotating shaft (410) and the rotating shaft base (420) and realizing bidirectional door opening, the bidirectional connecting piece (430) comprises a rotating shaft iron piece (431), and an upper rotor (432), an upper rotating shaft cover (433), a bidirectional torsion spring (434), a lower rotor (435) and a lower rotating shaft cover (436) which are sequentially sleeved on the rotating shaft iron piece (431) from top to bottom, the upper rotary shaft cover (433) and the lower rotary shaft cover (436) are accommodated in the rotary shaft base (420), the side walls of the upper rotating shaft cover (433) and the lower rotating shaft cover (436) are both provided with a stop body (437), a gear (421) stopping the stop body (437) is arranged in the rotating shaft base (420); the upper rotating shaft cover (433) is provided with an upper accommodating cavity for accommodating the upper rotor (432) and a lower accommodating cavity for accommodating the bidirectional torsion spring (434), a stopping part (4331) for stopping the upper rotor (432) is arranged in the upper accommodating cavity, and a clamping part (4361) for clamping the bidirectional torsion spring (434) is arranged in the lower accommodating cavity; the lower rotating shaft cover (436) is provided with an upper accommodating cavity for accommodating the bidirectional torsion spring (434) and a lower accommodating cavity for accommodating the lower rotor (435), the upper accommodating cavity is internally provided with a clamping part (4361) for clamping the bidirectional torsion spring (434) and a shaft hole (4362) for sleeving the bidirectional torsion spring (434), and a stopping part (4331) for stopping the lower rotor (435) is arranged in the lower accommodating cavity.

9. The door-closing safety fence according to claim 8, wherein: the pivot ironware (431) are provided with the edges and corners, go up the through-hole shape of rotor (432) and lower rotor (435) with the cross-sectional shape of pivot ironware (431) is unanimous, realizes with forming the block structure the linkage of pivot ironware (431) and upper rotor (432), lower rotor (435).

10. The door-closing safety fence according to claim 9, wherein: the inner door rotating shaft (410) is provided with a through hole, the rotating shaft iron piece (431) is inserted into the through hole, and the two-way connecting piece (430) is fixed through a nut.