CN112904504B

CN112904504B - Preformed end type extension splicing box

Info

Publication number: CN112904504B
Application number: CN201911228255.2A
Authority: CN
Inventors: 黄美金; 程淑玲; 张海焱
Original assignee: Fiberhome Telecommunication Technologies Co Ltd
Current assignee: Fiberhome Telecommunication Technologies Co Ltd
Priority date: 2019-12-04
Filing date: 2019-12-04
Publication date: 2022-09-30
Anticipated expiration: 2039-12-04
Also published as: CN112904504A

Abstract

The invention discloses a preformed end type extension splice closure, a box body comprises a lower cover and an upper cover which are mutually detachably connected and form an accommodating space, the lower cover is provided with a third connector, and the third connector is used for being spliced with an optical cable with a connector; the first connecting assembly comprises a first connecting body and a prefabricated connector jumper wire, the first connecting body is used for being assembled on the upper cover and being spliced with another optical cable with a connector, the connector jumper wire is used for being arranged in the accommodating space, and two ends of the connector jumper wire are respectively optically connected with the first connecting body and the third connecting body; the second connection component comprises a second connector and a connector tail fiber, the second connector is used for being assembled on the upper cover, the connector tail fiber is used for being arranged in the accommodating space, one end of the connector tail fiber is in optical connection with the third connector, and the other end of the connector tail fiber is in fusion connection with the optical cable to be extended, which enters the accommodating space through the second connector; the first connecting component and the second connecting component are alternatively assembled on the box body. The invention can meet the splicing requirement of jumper connection and on-site direct fusion splicing of optical fibers at the same time.

Description

Preformed end type extension splicing box

Technical Field

The invention relates to the technical field of optical fiber communication, in particular to a preformed end type extension splicing box.

Background

With the increasing and popularizing of high-speed information transmission requirements, optical fiber cables are more and more widely used as high-speed information transmission carriers. In the practical application of fiber-to-the-home, the fiber-extended connection is a very critical link for signal transmission.

The current optical fiber lengthening and splicing method generally adopts the following two methods:

(1) jumper connections, typically for "end-to-end" application scenarios, i.e. using connector jumpers, are assembled end-to-end on site through adapters; the general prefabricated forming (also called as 'end pre-forming type') in the market is a name for an optical cable connection application form, and the meaning of the prefabricated forming refers to that a connector or an adapter is assembled in advance at one end or two ends of a product before leaving a factory and can support a user to directly carry out plug and pull quick connection on site);

(2) the optical fiber is directly welded on site, generally aiming at the application scene of 'cable opposite end', namely a connector tail fiber is used, one end of the connector tail fiber is connected with a prefabricated optical cable with a connector, and the other end of the connector tail fiber is welded on site with an optical cable to be extended; the use of this method is relatively inexpensive, but requires specialized operators and equipment such as fusion splicers, and requires high construction and environmental protection for the signal quality of the cable and the avoidance of accidental damage to the cable.

In addition, no splice closure is available on the market that can satisfy both jumper connections and direct fusion splicing of optical fibers on site.

Disclosure of Invention

In view of the defects in the prior art, the present invention provides a preformed end type extended splice closure, which can simultaneously meet the splicing requirements of jumper connection and on-site direct fusion splicing of optical fibers.

In order to achieve the above purposes, the technical scheme adopted by the invention is as follows:

a pre-terminated elongated closure, comprising:

the box body comprises a lower cover and an upper cover which are mutually detachably connected and form an accommodating space, wherein the lower cover is provided with a third connector which is used for being spliced with an optical cable with a connector;

the first connecting assembly comprises a first connecting body and a prefabricated connector jumper wire, the first connecting body is used for being assembled on the upper cover and being spliced with another optical cable with a connector, the connector jumper wire is used for being arranged in the accommodating space, and two ends of the connector jumper wire are respectively optically connected with the first connecting body and the third connecting body;

the second connecting assembly comprises a second connecting body and a connector tail fiber, the second connecting body is used for being assembled on the upper cover, the connector tail fiber is arranged in the accommodating space, one end of the connector tail fiber is connected with the third connecting body in an optical mode, and the other end of the connector tail fiber is welded with the optical cable to be extended, which enters the accommodating space through the second connecting body;

and the first connecting component and the second connecting component are alternatively assembled on the box body.

Furthermore, the first connecting body comprises a prefabricated first adapter, when the first connecting component is arranged on the box body, the first adapter is arranged on the upper cover, one end of the first adapter is positioned outside the upper cover and used for being connected with an optical cable with a connector in an inserting mode, and the other end of the first adapter extends into the upper cover and used for being connected with the connector jumper in an optical mode.

Furthermore, a first blocking protrusion is arranged on the inner wall of the upper cover;

the first adapter comprises a first section and a second section which are connected with each other, the first section penetrates through the first blocking protrusion and is in threaded connection with a first nut, and the second section is located outside the upper cover and is respectively abutted, contacted or attached to two side walls of the first blocking protrusion.

Further, the first connecting body further comprises a first elastic sealing ring arranged between the second section and the first blocking protrusion.

Further, the second connector includes:

a nut;

the optical cable fixing structure is assembled on the upper cover when the second splicing assembly is assembled on the box body, one end of the optical cable fixing structure is positioned outside the upper cover and is in threaded connection with the screw cap, and the other end of the optical cable fixing structure extends into the upper cover;

and the nut and the optical cable fixing structure jointly form a cable running channel for the optical cable to be extended to pass through.

the nut is provided with an inlet through which an optical cable to be extended passes;

the optical cable fixing structure comprises a blocking part and a hollow screw rod, and the blocking part is sleeved on the outer wall of the screw rod;

the inlet is communicated with the screw rod and forms the cable running channel;

one end of the screw rod is positioned outside the upper cover and is in threaded connection with the screw cap, the other end of the screw rod penetrates through the first blocking protrusion and is in threaded connection with a second nut, and the second nut and the blocking portion are respectively abutted, contacted or attached to two side walls of the first blocking protrusion.

Further, the second connector also comprises a second elastic sealing ring arranged between the blocking part and the first blocking protrusion.

Furthermore, the second connector also comprises a cylindrical elastic sealing plug for the optical cable to be extended to pass through, the elastic sealing plug penetrates through the cable running channel, and the outer wall of the elastic sealing plug abuts against, contacts or is attached to the inner wall of the cable running channel.

Furthermore, a plurality of elastic arms are arranged on the end face of one end of the optical cable fixing structure in threaded connection with the nut, the elastic arms are circumferentially arranged along the end face of the optical cable fixing structure at intervals, and when the nut is in threaded connection with the optical cable fixing structure, the inner wall of the nut abuts against the elastic arms, so that the elastic arms are clamped on the elastic sealing plug together.

Furthermore, the third connector comprises a prefabricated second adapter, the second adapter is assembled on the lower cover, one end of the second adapter is positioned outside the lower cover and used for being connected with an optical cable with a connector in an inserting mode, and the other end of the second adapter extends into the lower cover and used for being connected with the connector jumper in an optical mode.

Furthermore, a second stop protrusion is arranged on the inner wall of the lower cover;

the second adapter comprises a third section and a fourth section which are connected with each other, the third section penetrates through the second retaining protrusion and is in threaded connection with a third nut, and the fourth section is located outside the lower cover and is respectively abutted against, contacted with or attached to two side walls of the second retaining protrusion together with the third nut.

Furthermore, the third connector also comprises a third elastic sealing ring arranged between the fourth section and the second retaining protrusion.

Furthermore, the outer wall of the lower cover is provided with at least one L-shaped clamping groove formed by communicating a longitudinal groove and a transverse groove, which are distributed along the circumferential direction;

the upper cover is characterized in that at least one clamping portion distributed along the circumferential direction is arranged on the inner wall of the upper cover, and the clamping portion penetrates through the longitudinal groove and then is in rotary clamping connection with the transverse groove.

Furthermore, a third baffle protrusion is arranged on the outer wall of the lower cover, and an installation groove is formed between the third baffle protrusion and the end wall of the upper cover;

and a fourth elastic sealing ring is arranged in the mounting groove, and two side walls of the fourth elastic sealing ring are respectively abutted, contacted or attached to the third blocking protrusion and the end wall of the upper cover.

Furthermore, a sleeve groove for installing a fusion welding protective sleeve is arranged on the inner wall of the lower cover or the upper cover.

Compared with the prior art, the invention has the advantages that:

the preformed end type extension splice closure provided by the invention simultaneously considers the splicing schemes of prefabricating an end-to-end connection and a cable opposite end connection, simultaneously meets the requirements of jumper wire connection and direct fusion splicing of optical fibers on site, can realize the plug-and-play extension function of the optical cable with the prefabricated ribbon connector aiming at the scene of prefabricating the end-to-end connection, avoids the pollution of the end face of the connector in the manual disassembly and assembly process of the closure body, and is convenient and fast to operate.

Drawings

Fig. 1 is a schematic structural diagram of a cartridge provided in an embodiment of the present invention;

FIG. 2 is an exploded view of a cartridge provided by an embodiment of the present invention;

FIG. 3 is an exploded view of the enclosure and the first splice assembly according to an embodiment of the present invention;

FIG. 4 is an exploded view of a cassette and a second splice assembly according to an embodiment of the present invention;

fig. 5 is an exploded view of a first splice assembly (with a top cover) according to an embodiment of the present invention;

fig. 6 is a cross-sectional view of a first splice assembly provided in accordance with an embodiment of the present invention when assembled with a top cover;

fig. 7 is an exploded view of a second splice assembly (with a top cover) according to an embodiment of the present invention;

fig. 8 is a cross-sectional view of a second splice assembly provided in accordance with an embodiment of the present invention when assembled with an upper cover;

fig. 9 is a schematic view of a lower cover structure according to an embodiment of the present invention.

In the figure: A. an accommodating space; 1. a lower cover; 10. the second stop bulge; 11. an L-shaped clamping groove; 110. a longitudinal groove; 111. a transverse groove; 112. a containing groove; 12. a third baffle protrusion; 13. a fourth elastic sealing ring; 14. a casing groove; 15. a wall-mounted support; 2. an upper cover; 20. a first blocking protrusion; 21. a clamping part; 3. a third connecting body; 30. a second adapter; 300. a third stage; 301. a fourth stage; 31. a third nut; 32. a third elastic sealing ring; 4. an optical cable with a connector; 5. a first connecting body; 50. a first adapter; 500. a first stage; 501. a second section; 51. a first nut; 52. a first elastic sealing ring; 6. a connector jumper wire; 7. a second connector; 70. an optical cable fixing structure; 700. a blocking part; 701. a screw; 702. a resilient arm; 71. a nut; 710. an inlet; 72. a second nut; 73. an elastic sealing plug; 74. a second elastic sealing ring; 8. connecting a tail fiber of the connector; 80. welding a protective sleeve; 9. the optical cable is to be extended.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples.

A first embodiment of the present invention provides a preform-end type elongated closure that includes a body, a first splice assembly, and a second splice assembly.

Referring to fig. 1 and fig. 2, the box body comprises a lower cover 1 and an upper cover 2 which are detachably connected with each other and form an accommodating space a, the lower cover 1 is provided with a third connecting body 3 in group, and the third connecting body 3 is used for being spliced with an optical cable 4 with a connector;

referring to fig. 3, the first splicing assembly includes a first connecting body 5 and a prefabricated connecting joint jumper 6, for example, a prefabricated SC/APC connecting joint jumper, the first connecting body 5 is configured to be assembled on the upper cover 2 and inserted into another optical cable 4 with a connecting joint, the connecting joint jumper 6 is configured to be disposed in the accommodating space a, and two ends of the connecting joint jumper 6 are respectively optically connected to the first connecting body 5 and the third connecting body 3;

referring to fig. 4, the second splicing assembly includes a second connector 7 and a connector pigtail 8, such as an SC/APC connector pigtail, the second connector 7 is configured to be assembled on the upper cover 2, the connector pigtail 8 is configured to be disposed in the accommodating space a, and one end of the connector pigtail 8 is optically connected to the third connector 3, and the other end of the connector pigtail is fusion-connected to an optical cable 9 (see fig. 7) to be extended, which enters the accommodating space a through the second connector 7;

In this embodiment, the third connector 3 is plugged with an optical cable 4 with a connector, the first connector 5 provided by the first splicing assembly can be plugged with another optical cable 4 with a connector, and then is optically connected with the first connector 5 and the third connector 3 through the connector jumper 6 to realize the extension splicing of the two optical cables 4 with connectors, because the third connector 3 and the first connector 5 can be directly plugged with the optical cable 4 with a connector, when the first splicing assembly is arranged in the box body, the optical cable 4 with a connector can be plugged and used, and the field quick installation under the 'end-to-end' application scene is ensured.

And the second connector 7 and the connector tail fiber 8 provided by the second splicing component can realize the on-site direct fusion of the optical cable 9 to be extended.

Therefore, the end type extension splice box in advance who provides of this embodiment compromises the scheme of continuing of prefabricating into "end to end" and "cable opposite end" simultaneously, satisfies jumper connection and the on-the-spot direct butt fusion's of optic fibre demand simultaneously, to prefabricating into the scene of end to end, can realize taking the prefabricated optical cable of banding connector to insert the extended function of using promptly, avoids leading to the fact connector terminal surface to pollute among the artificial box body dismouting in-process, the simple operation.

Referring to fig. 3, a second embodiment of the present invention provides a pre-terminated extension closure, which differs from the first embodiment in that: the first connecting body 5 includes a prefabricated first adaptor 50, such as a prefabricated SC/APC circular adaptor, when the first splicing assembly is assembled in the box body, the first adaptor 50 is assembled on the upper cover 2, one end of the first adaptor is located outside the upper cover 2 and is used for plugging the optical cable 4 with the connector, and the other end of the first adaptor extends into the upper cover 2 and is used for optically connecting with the connector jumper 6.

More specifically, referring to fig. 5 and 6, the inner wall of the upper cover 2 is provided with a first blocking protrusion 20, in this embodiment, the first blocking protrusion 20 is in an annular structure, but of course, a plurality of protrusions protruding from the inner wall of the upper cover 2 may also be provided, and the plurality of protrusions are spaced and form an annular shape; the first adapter 50 includes a first section 500 and a second section 501 connected with each other, the first section 500 passes through the first blocking protrusion 20 and is screwed with a first nut 51, the second section 501 is located outside the upper cover 2 and is respectively abutted, contacted or attached to two side walls of the first blocking protrusion 20 with the first nut 51, the first adapter 50 is fixed on the upper cover 2 through the first blocking protrusion 20 and matching with the first nut 51, the first blocking protrusion 20 uses an annular structure, and dust and the like can be prevented from entering the accommodating space a.

Referring to fig. 5 and 6, the first connecting body 5 further includes a first elastic sealing ring 52 disposed between the second segment 501 and the first stopping protrusion 20, so as to realize a long-term reliable sealing function of the closure.

Referring to fig. 5, the outer wall of the second section 501 is not circular, but two planes are provided on the circular outer wall, and meanwhile, the inner wall of the upper cover 2 is adapted to the outer wall of the second section 501 (see the left end in fig. 1), which has the advantage that when the first section 500 is installed in the upper cover 2 and is fastened by the first nut 51, the first section 500 can be prevented from rotating together when the first nut 51 is screwed, and the first adapter 50 is prevented from being installed insecurely.

Referring to fig. 4, a third embodiment of the present invention provides a preform-end type extension closure, which differs from the first embodiment in that: the second connector 7 comprises a nut 71 and an optical cable fixing structure 70, when the second splicing component is assembled on the box body, the optical cable fixing structure 70 is assembled on the upper cover 2, one end of the optical cable fixing structure is positioned outside the upper cover 2 and is in threaded connection with the nut 71, and the other end of the optical cable fixing structure extends into the upper cover 2; and, the nut 71 and the cable fixing structure 70 together form a cable passage (not shown) for the cable 9 to be extended to pass through.

More specifically, referring to fig. 7 and 8, the inner wall of the upper cover 2 is provided with a first stopping protrusion 20; the nut 71 is provided with an inlet 710 for the optical cable 9 to be extended to pass through; the optical cable fixing structure 70 comprises a retaining part 700 and a hollow screw 701, wherein the retaining part 700 is sleeved on the outer wall of the screw 701; the inlet 710 is communicated with the screw 701 and forms a cabling channel; one end of the screw 701 is located outside the upper cover 2 and is screwed with the nut 71, the other end passes through the first retaining protrusion 20 and is screwed with a second nut 72, and the second nut 72 and the retaining portion 700 respectively abut against, contact or attach to two side walls of the first retaining protrusion 20.

Referring to fig. 7 and 8, the second connecting body 7 further includes a second elastic sealing ring 74 disposed between the retaining portion 700 and the first retaining protrusion 20, so as to achieve a long-term reliable sealing function of the closure.

Referring to fig. 7, the outer wall of the retaining portion 700 is not circular, but is octagonal, and meanwhile, the inner wall of the upper cover 2 is fitted with the outer wall of the retaining portion 700 (see the left end in fig. 1), which has the advantage that when the screw 701 is installed in the upper cover 2 and fastened by the second nut 72, the screw 701 can be prevented from rotating together when the second nut 72 is screwed, and the optical cable fixing structure 70 is prevented from being installed insecurely.

Referring to fig. 7 and 8, a fourth embodiment of the present invention provides a pre-terminated splice closure, which differs from the third embodiment in that: the second connector 7 further comprises a cylindrical elastic sealing plug 73 for the optical cable 9 to be extended to pass through, the elastic sealing plug 73 penetrates through the cable channel, the outer wall of the elastic sealing plug 73 abuts against, contacts or is attached to the inner wall of the cable channel, and the sealing and fixing functions of the optical cable 9 to be extended can be achieved through the elastic sealing plug 73.

Referring to fig. 7, a plurality of elastic arms 702 are disposed on an end surface of the optical cable fixing structure 70 screwed with the nut 71, the elastic arms 702 are circumferentially spaced along the end surface of the optical cable fixing structure 70, and when the nut 71 is screwed on the optical cable fixing structure 70, an inner wall of the nut 71 abuts against the elastic arms 702, so that the elastic arms 702 are clamped on the elastic sealing plug 73 together.

Due to the elastic arm 702, in the locking and fixing process of the nut 71, the elastic arm 702 is gradually compressed, and the elastic arm 702 presses the elastic sealing plug 73, so that the optical cable 9 to be extended is sealed and fixed.

Referring to fig. 3, a fifth embodiment of the present invention provides a pre-terminated splice closure, which differs from the first embodiment in that: the third connector 3 comprises a prefabricated second adapter 30, the second adapter 30 is assembled on the lower cover 1, one end of the second adapter is positioned outside the lower cover 1 and is used for being plugged with an optical cable 4 with a connector, and the other end of the second adapter extends into the lower cover 1 and is used for being optically connected with a connector jumper 6.

More specifically, referring to fig. 1 and 3, the inner wall of the lower cover 1 is provided with a second retaining protrusion 10, in this embodiment, the second retaining protrusion 10 is in an annular structure, but of course, a plurality of protrusions may also be formed by protruding the inner wall of the lower cover 1, and the plurality of protrusions are arranged at intervals and enclose an annular shape; the second adapter 30 includes a third segment 300 and a fourth segment 301 connected to each other, the third segment 300 passes through the second protrusion 10 and is screwed with a third nut 31, and the fourth segment 301 is located outside the lower cover 1 and abuts against, contacts or adheres to two sidewalls of the second protrusion 10 with the third nut 31 respectively.

Referring to fig. 3, the third connecting body 3 further includes a third elastic sealing ring 32 disposed between the fourth section 301 and the second protrusion 10, so as to realize a long-term reliable sealing function of the closure.

As can be seen from fig. 3, the third connecting body 3 and the first connecting body 5 have the same structure, and in practical use, the third connecting body 3 and the first connecting body 5 can be made into the same structure, so that on one hand, the third connecting body 3 and the first connecting body 5 can be ensured to be mutually universal, and on the other hand, a set of mold can be used during manufacturing, so as to reduce the production cost.

Similarly, the first nut 51, the third nut 31 and the second nut 72 may have the same structure, and may be used in common during assembly, and do not need to be recognized to match with the corresponding connecting body, thereby facilitating installation.

Referring to fig. 2 and 9, a sixth embodiment of the present invention provides a preform-end type extension closure, which differs from the first embodiment in that: the outer wall of the lower cover 1 is provided with at least one L-shaped clamping groove 11 formed by communicating a longitudinal groove 110 and a transverse groove 111 and distributed along the circumferential direction; at least one clamping portion 21 distributed along the circumferential direction is arranged on the inner wall of the upper cover 2, and the clamping portion 21 penetrates through the longitudinal groove 110 and then is rotationally clamped with the transverse groove 111 to achieve the self-locking quick-dismounting characteristic of the upper cover 2 and the lower cover 1.

Referring to fig. 9, one end of the transverse groove 111 away from the longitudinal groove 110 extends toward the upper cover 2 and forms a receiving groove 112 for receiving the fastening portion 21, and when the fastening portion 21 passes through the longitudinal groove 110 and is rotatably fastened to the transverse groove 111, the fastening portion 21 is received in the receiving groove 112, so that the upper cover 2 and the lower cover 1 are prevented from being separated from each other in the using process or under an unexpected condition.

Referring to fig. 1 and 2, a third stopping protrusion 12 is arranged on the outer wall of the lower cover 1, and an installation groove is formed between the third stopping protrusion 12 and the end wall of the upper cover 2; a fourth elastic sealing ring 13 is arranged in the mounting groove, and two side walls of the fourth elastic sealing ring 13 are respectively abutted, contacted or attached with the third blocking protrusion 12 and the end wall of the upper cover 2, so that the long-term reliable sealing function of the box body is realized.

Referring to fig. 9, the inner wall of the lower cover 1 or the upper cover 2 is provided with a sleeve groove 14, and the sleeve groove 14 is used for installing a fusion protection sleeve 80 (see fig. 4).

Referring to fig. 1 and 3, a wall hanging bracket 15 is further provided on the outer wall of the box body.

The present invention is not limited to the above-described embodiments, and it will be apparent to those skilled in the art that various modifications and improvements can be made without departing from the principle of the present invention, and such modifications and improvements are also considered to be within the scope of the present invention. Those not described in detail in this specification are within the skill of the art.

Claims

1. A preformed extended closure, comprising:

the box body comprises a lower cover (1) and an upper cover (2) which are detachably connected with each other and form an accommodating space (A), wherein the lower cover (1) is provided with a third connecting body (3), and the third connecting body (3) is used for being spliced with an optical cable (4) with a connecting head;

the first connecting assembly comprises a first connecting body (5) and a prefabricated connector jumper wire (6), wherein the first connecting body (5) is used for being assembled on the upper cover (2) and being spliced with another optical cable (4) with a connector, the connector jumper wire (6) is used for being arranged in the accommodating space (A), and two ends of the connector jumper wire are respectively optically connected with the first connecting body (5) and the third connecting body (3);

the second connection assembly comprises a second connector (7) and a connector tail fiber (8), the second connector (7) is used for being assembled on the upper cover (2), the connector tail fiber (8) is used for being arranged in the accommodating space (A), one end of the connector tail fiber is in optical connection with the third connector (3), and the other end of the connector tail fiber is in fusion connection with an optical cable (9) to be extended, which enters the accommodating space (A) through the second connector (7);

2. The pre-terminated extension closure of claim 1, wherein:

first connector (5) are including prefabricated first adapter (50), work as first subassembly group that continues locates when the box body, first adapter (50) group is located on upper cover (2), and its one end is located outside upper cover (2) and be used for the optical cable (4) of plug band connector, the other end stretch into in upper cover (2) and be used for with connector jumper wire (6) optical connection.

3. The pre-terminated extension closure of claim 2, wherein:

a first baffle bulge (20) is arranged on the inner wall of the upper cover (2);

the first adapter (50) comprises a first section (500) and a second section (501) which are connected with each other, the first section (500) penetrates through the first retaining protrusion (20) and is in threaded connection with a first nut (51), and the second section (501) is located outside the upper cover (2) and is respectively abutted, contacted or attached to two side walls of the first retaining protrusion (20) through the first nut (51).

4. The pre-terminated extension closure of claim 3, wherein:

the first connecting body (5) further comprises a first elastic sealing ring (52) arranged between the second section (501) and the first baffle protrusion (20).

5. The pre-terminated extension closure of claim 1, wherein the second connector (7) comprises:

a nut (71);

the optical cable fixing structure (70) is assembled on the upper cover (2), one end of the optical cable fixing structure (70) is positioned outside the upper cover (2) and is in threaded connection with the screw cap (71), and the other end of the optical cable fixing structure (70) extends into the upper cover (2);

and the screw cap (71) and the optical cable fixing structure (70) together form a cable running channel for the optical cable (9) to be extended to pass through.

6. The pre-terminated extension closure of claim 5, wherein:

a first baffle bulge (20) is arranged on the inner wall of the upper cover (2);

the nut (71) is provided with an inlet (710) for the optical cable (9) to be extended to pass through;

the optical cable fixing structure (70) comprises a retaining part (700) and a hollow screw rod (701), wherein the retaining part (700) is sleeved on the outer wall of the screw rod (701);

the inlet (710) is communicated with the screw (701) and forms the cabling channel;

one end of the screw rod (701) is located outside the upper cover (2) and is in threaded connection with the screw cap (71), the other end of the screw rod penetrates through the first retaining protrusion (20) and is in threaded connection with a second nut (72), and the second nut (72) and the retaining portion (700) are in contact with two side walls of the first retaining protrusion (20) respectively.

7. The preform-ended extension closure of claim 6, wherein:

the second connecting body (7) further comprises a second elastic sealing ring (74) arranged between the retaining part (700) and the first retaining protrusion (20).

8. The preform-ended extension closure of claim 5, wherein: the second connecting body (7) further comprises a cylindrical elastic sealing plug (73) for the optical cable (9) to be extended to pass through, the elastic sealing plug (73) penetrates through the cable running channel, and the outer wall of the elastic sealing plug is in contact with the inner wall of the cable running channel.

9. The pre-terminated extension closure of claim 8, wherein: optical cable fixed knot constructs (70) with be equipped with a plurality of elastic arms (702) on the one end terminal surface of nut (71) spiro union, elastic arm (702) are followed optical cable fixed knot constructs (70) terminal surface circumference interval arrangement, work as nut (71) spiro union is in when optical cable fixed knot constructs (70), nut (71) inner wall supports and holds elastic arm (702), so that each elastic arm (702) centre gripping jointly in on elastic sealing plug (73).

10. The preform-ended extension closure of claim 1, wherein:

the third connector (3) comprises a prefabricated second adapter (30), the second adapter (30) is assembled on the lower cover (1), one end of the second adapter is located outside the lower cover (1) and used for being inserted into an optical cable (4) with a connector, and the other end of the second adapter extends into the lower cover (1) and used for being connected with the connector jumper (6) in an optical mode.

11. The pre-terminated extension closure of claim 10, wherein:

a second stop bulge (10) is arranged on the inner wall of the lower cover (1);

the second adapter (30) comprises a third section (300) and a fourth section (301) which are connected with each other, the third section (300) penetrates through the second retaining protrusion (10) and is in threaded connection with a third nut (31), and the fourth section (301) is located outside the lower cover (1) and is respectively abutted against, contacted with or attached to two side walls of the second retaining protrusion (10) together with the third nut (31).

12. The pre-terminated extension closure of claim 11, wherein:

the third connecting body (3) further comprises a third elastic sealing ring (32) arranged between the fourth section (301) and the second retaining protrusion (10).

13. The preform-ended extension closure of claim 1, wherein:

the outer wall of the lower cover (1) is provided with at least one L-shaped clamping groove (11) which is formed by communicating a longitudinal groove (110) with a transverse groove (111) and is distributed along the circumferential direction;

be equipped with on upper cover (2) inner wall along at least one joint portion (21) of circumference distribution, joint portion (21) pass vertical recess (110) back and horizontal recess (111) rotatory joint.

14. The pre-terminated extension closure of claim 13, wherein:

a third baffle protrusion (12) is arranged on the outer wall of the lower cover (1), and an installation groove is formed between the third baffle protrusion (12) and the end wall of the upper cover (2);

and a fourth elastic sealing ring (13) is arranged in the mounting groove, and two side walls of the fourth elastic sealing ring (13) are respectively in contact with the third blocking protrusion (12) and the end wall of the upper cover (2).

15. The pre-terminated extension closure of claim 1, wherein: and a sleeve groove (14) for installing a welding protection sleeve (80) is formed in the inner wall of the lower cover (1) or the upper cover (2).