CN108157220B

CN108157220B - Pet traction device

Info

Publication number: CN108157220B
Application number: CN201711495010.7A
Authority: CN
Inventors: 朱哲昊
Original assignee: Individual
Current assignee: Individual
Priority date: 2017-12-31
Filing date: 2017-12-31
Publication date: 2021-02-02
Anticipated expiration: 2037-12-31
Also published as: WO2019128303A1; CN108157220A

Abstract

The invention discloses a pet traction device, which comprises a shell, a rotary disc, a locking piece, a locking button and a first connecting piece, wherein the shell is provided with a first hole, the first connecting piece is movably arranged in the first hole, the first end of the first connecting piece is hinged in the shell, the second end of the first connecting piece is provided with a pressing part, the rotary disc is rotatably arranged in the shell, and the peripheral edge of the rotary disc is uniformly provided with clamping teeth; the latch fitting articulates in the casing, is equipped with contact site and latch on the latch fitting, and the contact site contacts with the portion of pushing down, and the latch supports the latch, and the lock button is established on first link up, and when the lock button was pushed down, the lock button supported first link up, and the first end of first link up rotates in the casing, and the portion of pushing down moves and supports the contact site, and then makes the latch fitting rotate in the casing to make the latch fitting support the latch. The invention can solve the problem that in the prior art, when a pet is frightened or is ready to attack other people and suddenly runs away, an owner cannot hold the pet through the traction device, and safety accidents are easy to happen.

Description

Pet traction device

Technical Field

The invention relates to the technical field of pet care products, in particular to a pet traction device.

Background

With the coming of aging population, the living pressure of young people is increased year by year and the young people often cannot accompany parents, and the national endowment organization is still imperfect, so more old people tend to keep dogs and cats, meanwhile some young people also like to keep cats and dogs, with the increase of the number of pets, the problems follow the increase of the number of pets, the pets run around randomly, the pets are lost, the situations of defecation and the like are increasingly prominent, people use dog chains, ropes and the like to tie the pets, when going out, the ropes are sleeved on the necks of the dogs to cause discomfort of animals, people also do not conveniently control the pets, the force needed is large, when the pets are frightened or are ready to attack to run away suddenly, the hauling ropes coiled on the reels can be quickly pulled out by other people, the pets cannot be pulled by the tractor, and safety accidents are easy to happen.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention aims to provide a pet traction device, which can solve the problem that in the prior art, when a pet is frightened or is prepared to attack other people and suddenly runs away, an owner cannot pull the pet through the traction device, and safety accidents are easy to happen.

The purpose of the invention can be realized by adopting the following technical scheme:

a pet traction device comprises a shell, a rotary disc, a locking piece, a locking button and a first connecting piece;

the shell is provided with a first hole, the first connecting piece is movably arranged in the first hole, the first end of the first connecting piece is hinged in the shell, so that the first end of the first connecting piece rotates in the shell, and the second end of the first connecting piece is provided with a pressing part;

the rotary disc is rotatably arranged in the shell, and a plurality of clamping teeth are uniformly arranged on the peripheral edge of the rotary disc;

the locking piece is hinged in the shell, so that the locking piece rotates in the shell, the locking piece is provided with a contact part and a clamping tongue, the contact part is contacted with the pressing part, and the clamping tongue is propped against the clamping teeth;

the lock button is arranged on the first connecting piece, when the lock button is pressed down, the lock button supports the first connecting piece, the first end of the first connecting piece rotates in the shell, the pressing-down part moves downwards and supports the contact part, the lock piece rotates in the shell, and the clamping tongue supports the clamping teeth.

The locking button is provided with a locking column, the first connecting piece is provided with a long circular hole, and the second connecting piece is provided with a second hole and a clamping part;

the lock cylinder penetrates through the long round hole and is inserted into the second hole, so that the lock cylinder drives the second connecting piece to move along the length direction of the long round hole.

The connecting rod is movably arranged in the shell so as to enable the connecting rod to move back and forth in the shell;

when external force makes first link up the piece and pushes down and makes the lock post drive second link up the piece and remove along the length direction of slotted hole, the joint of card stop portion is in the connecting rod below to make the portion of pushing down support the contact site, and then make the latch support the latch.

The shell is provided with a third hole, the third hole is rectangular, one end of the lock catch penetrates through the third hole and is arranged at the first end of the connecting rod, and the first end of the lock catch moves along the length direction of the rectangular third hole;

when the first end of the lock catch moves along the length direction of the rectangular third hole due to external force, the lock catch drives the connecting rod to move synchronously;

the first end of the elastic sheet is arranged on the locking piece, and the second end of the elastic sheet is propped against the inner wall of the shell.

Further, still include the locking lever spare, locking lever spare middle part position and shells inner wall are articulated each other, and the connecting rod is equipped with fixed breach, and when the hasp drove the connecting rod and carries out synchronous motion, locking lever spare rotated round shells inner wall for the first end joint of locking lever spare is in fixed breach.

The driving piece is arranged on the inner wall of the shell in a sliding mode, the first end of the driving piece is provided with a slope part, and the second spring is arranged on the second end of the driving piece;

external force makes the driving medium when the shells inner wall slides, and slope portion is supporting the opposite side of pressing locking lever spare second end, and then makes the first end joint of locking lever spare in fixed breach, perhaps for the first end of locking lever spare keeps away from fixed breach.

Furthermore, the rotary cover is arranged between the rotary plate and the inner wall of the shell;

the carousel is equipped with the fourth hole, and the spiral cover is equipped with and stops the depressed part, and the fixed axle passes the fourth hole and the joint stops on the depressed part.

Furthermore, the shell is provided with a rope cover, and a guide outlet is arranged on the rope cover;

the rope cover comprises a first cover body and a second cover body, and the first cover body and the second cover body are mutually covered together to form a complete rope cover.

Furthermore, the device also comprises a clockwork spring, a connecting buckle, a rope lock shaft and a traction rope;

the first end of the spring is arranged on the rotary disc, the spring is wound on the rotary disc, the second end of the spring is connected with one side of the connecting buckle, the other side of the connecting buckle is connected with the traction rope through the rope lock shaft, namely, the second end of the spring is connected with the first end of the traction rope sequentially through the connecting buckle and the rope lock shaft, and the second end of the traction rope penetrates through the outlet;

the shell is provided with a handle, a screwdriver and a cutter cover shell are arranged in the handle, and the screwdriver is placed in the cutter cover shell.

Further, the shell comprises a first shell and a second shell, and the first shell and the second shell are mutually covered together to form a complete shell.

Compared with the prior art, the invention has the beneficial effects that: the pet traction device comprises a shell, a rotary disc, a locking piece, a locking button and a first connecting piece, wherein a first hole is formed in the shell, the first connecting piece is movably arranged in the first hole, the first end of the first connecting piece is hinged and arranged in the shell, the first end of the first connecting piece rotates in the shell, a pressing part is formed at the second end of the first connecting piece, in addition, the rotary disc is rotatably arranged in the shell (a clockwork spring and a traction rope are sequentially arranged on the rotary disc), a plurality of clamping teeth are uniformly formed at the peripheral edge of the rotary disc, the locking piece is hinged and arranged in the shell, so that the locking piece rotates in the shell, a contact part and a clamping tongue are formed on the locking piece, the contact part is in contact with the pressing part, the clamping tongue abuts against the clamping teeth, the locking button is arranged on the first connecting piece, when the pet traction device is used, an external force presses the locking button, so that the locking button is pressed downwards, and at the locking button abuts, make first link up the first end of union piece and rotate in the casing, meanwhile, the portion of pushing down of first link up union piece second end down removes and supports the contact site, and then make the latch fitting rotate in the casing, latch fitting in the rotation makes the latch fitting support the latch of carousel, can realize "stopping", avoid receiving frightening or preparing to attack other people and when running away suddenly when the pet, the haulage rope of coiling on the carousel can be pulled out fast, and "stopping", the haulage rope that prevents to coil at the carousel that can be fine can be pulled out fast, and is very safe. The problem that in the prior art, when a pet is frightened or is ready to attack other people and suddenly runs away, the owner cannot pull the pet through the traction device, and safety accidents are easy to happen can be solved.

Drawings

FIG. 1 is a schematic view of the construction of the pet leash device of the present invention;

FIG. 2 is a schematic view of the pet leash device shown in FIG. 1, wherein the second cover and the second housing are hidden;

FIG. 3 is an enlarged schematic view of portion A of the pet leash device shown in FIG. 2;

FIG. 4 is an enlarged schematic view of portion B of the pet leash device shown in FIG. 2;

FIG. 5 is a schematic view of the pet leash device shown in FIG. 1 at another angle;

FIG. 6 is a schematic view of the pet leash device shown in FIG. 5 with the first cover and the first housing hidden;

FIG. 7 is an enlarged schematic view of the portion C of the pet leash device shown in FIG. 6;

FIG. 8 is a schematic view of the structure of the turntable of the pet leash device shown in FIG. 6;

fig. 9 is a schematic view of the structure of the locking element of the pet leash device shown in fig. 2;

fig. 10 is a schematic view of a first connector of the pet leash device of fig. 6;

fig. 11 is a schematic view of a second connector of the pet leash device of fig. 6;

fig. 12 is a schematic structural view of a lock button in the pet leasing device shown in fig. 2.

In the figure: 11. a first housing; 12. a second housing; 131. a first cover body; 132. a second cover body; 2. a turntable; 21. clamping teeth; 22. a fourth aperture; 3. a lock; 31. a contact portion; 32. a latch; 4. a lock knob; 41. a lock cylinder; 5. a first joining member; 51. a pressing part; 52. a long round hole; 6. a second joining member; 61. a second hole; 62. a locking part; 7. a connecting rod; 71. fixing the notch; 8. locking; 9. a spring plate; 101. a lock bar member; 102. a transmission member; 103. screwing a cover; 1031. a locking recessed part; 104. a connecting buckle; 105. a hauling rope; 106. provided is a screwdriver.

Detailed Description

The present invention will be further described with reference to the accompanying drawings and the detailed description, and it should be noted that any combination of the embodiments or technical features described below can be used to form a new embodiment without conflict.

Referring to fig. 1-12, the invention relates to a pet traction device, which comprises a shell, a turntable 2, a locking piece 3, a locking button 4, a first connecting piece 5, a second connecting piece 6, a connecting rod 7, a lock catch 8, a spring sheet 9, a locking rod piece 101, a first spring, a second spring, a transmission piece 102, a spiral cover 103, a fixed shaft, a spiral spring, a connecting buckle 104, a rope locking shaft and a traction rope 105.

The housing comprises a first housing 11 and a second housing 12, and the first housing 11 and the second housing 12 are mutually covered together, so that a complete housing is formed between the first housing 11 and the second housing 12.

In this embodiment, the first housing 11 and the second housing 12 are fixed to each other by being fastened together. In other embodiments, the first housing 11 and the second housing 12 may be fixed to each other by bolts, or the first housing 11 and the second housing 12 may be fixed to each other by inserting, or the first housing 11 and the second housing 12 may be fixed to each other by screws, as long as the first housing 11 and the second housing 12 are fixed to each other by covering, so that a complete housing is formed between the first housing 11 and the second housing 12.

Furthermore, the housing is provided with a rope cover, and a guide outlet is formed on the rope cover, through which the pulling rope 105 can pass, wherein the rope cover comprises a first cover body 131 and a second cover body 132, and the first cover body 131 and the second cover body 132 are mutually covered together, so that a complete rope cover is formed between the first cover body 131 and the second cover body 132.

In this embodiment, the first cover 131 and the second cover 132 are fastened together. In other embodiments, the first cover 131 and the second cover 132 may be covered and fixed together by bolts, or the first cover 131 and the second cover 132 may be covered and fixed together by inserting, or the first cover 131 and the second cover 132 may be covered and fixed together by screws, as long as the first cover 131 and the second cover 132 are covered and fixed together, so that a complete rope cover is formed between the first cover 131 and the second cover 132.

A first hole is formed at the top of the housing, a first connecting member 5 is movably installed in the first hole, and a first end of the first connecting member 5 is hinge-installed in the housing (for example, the first end of the first connecting member 5 is rotatably inserted into the inner wall of the first housing 11, or the first end of the first connecting member 5 is rotatably inserted into the inner wall of the second housing 12), so that the first end of the first connecting member 5 rotates in the housing, that is, the first connecting member 5 rotates around the inner wall of the housing, and a pressing portion 51 is formed at a second end of the first connecting member 5, further, the rotating disc 2 is rotatably installed in the housing (the first end of the clockwork spring is fixedly installed on the rotating disc 2, and the clockwork spring is wound on the rotating disc 2, the second end of the clockwork spring is connected to one side of a connecting buckle 104, and the other side of the connecting buckle 104 is connected to the traction rope 105 through a rope lock shaft, that the second end of, the second end of the hauling rope 105 passes through the leading-out opening), and, a plurality of latch 21 are evenly formed on the periphery of the rotating disc 2, the locking piece 3 is hinged and installed in the shell, so that the locking piece 3 rotates in the shell, namely, the locking piece 3 can rotate around the inner wall of the shell, furthermore, a contact part 31 and a latch 32 are formed on the locking piece 3, wherein, the contact part 31 is contacted with the lower pressing part 51, the latch 32 is propped against the latch 21, the locking button 4 is installed on the first linking piece 5, when the pet traction device is used, an external force presses the locking button 4, so that the locking button 4 is pressed downwards, at the moment, the locking button 4 is propped against the first linking piece 5, so that the first end of the first linking piece 5 rotates in the shell, meanwhile, the lower pressing part 51 of the second end of the first linking piece 5 moves downwards and props against the contact part 31, so that the locking piece 3 rotates in the shell, the rotating locking piece 3 makes the latch 32 prop against the latch 21 of the rotating, can realize "snub" (for example, need control haulage rope 105 temporarily when certain length, external force is pressed lock button 4 for lock button 4 makes latch 32 of latch 3 support the latch 21 of carousel 2 through first link 5, can realize "snub", when loosening lock button 4, haulage rope 105 can automatic withdrawal under the effort of clockwork spring), when avoiding when the pet receives the frightening or prepares to attack other people and run out suddenly, haulage rope 105 coiled on carousel 2 can be torn fast, and "snub", can be fine prevent that haulage rope 105 coiled at carousel 2 can be torn fast, and is very safe.

In addition, shell fragment 9 first end fixed mounting is on latch fitting 3, and shell fragment 9 second end supports and supports shells inner wall, and when loosening lock button 4, latch fitting 3 rotates round shells inner wall under the spring action of shell fragment 9, can avoid latch 32 of latch fitting 3 to support latch 21 of carousel 2 to haulage rope 105 is automatic withdrawal under the effort of clockwork spring.

The second connecting piece 6 is located below the first connecting piece 5, the locking column 41 is formed on the locking button 4, the long circular hole 52 is formed on the first connecting piece 5, the second hole 61 is formed on the second connecting piece 6, one end of the locking column 41 penetrates through the long circular hole 52 until one end of the locking column 41 is inserted into the second hole 61, and therefore the locking column 41 can drive the second connecting piece 6 to move along the length direction of the long circular hole 52.

The connecting rod 7 is movably installed in the casing so as to enable the connecting rod 7 to move back and forth in the casing, when the external force enables the first linking piece 5 to press down and the lock column 41 to drive the second linking piece 6 to move along the length direction of the long circular hole 52 (namely, the external force presses the lock button 4 to enable the lock button 4 to be pressed down, at this time, the lock button 4 abuts against and drives the first linking piece 5 to move downwards, meanwhile, the external force enables the lock column 41 on the lock button 4 to drive the second linking piece 6 to move forwards along the length direction of the long circular hole 52), as the second linking piece 6 is also formed with the clamping part 62, the clamping part 62 can be clamped below the connecting rod 7 so as to enable the pressing part 51 to abut against the contact part 31, and further enable the clamping tongue 32 to abut against the clamping tooth 21, the traction rope 105 can be locked at a certain length, which is very convenient, and when a pet is suddenly opened due to scare or prepare to attack others, the pulling rope 105 wound on the turntable 2 can be pulled out quickly, so that the pulling rope 105 wound on the turntable 2 can be prevented from being pulled out quickly, and the safety is high.

A third hole is formed in the housing, the third hole is rectangular, one end of the latch 8 penetrates through the third hole, one end of the latch 8 is fixedly mounted at the first end of the connecting rod 7, when the first end of the latch 8 moves along the length direction of the rectangular third hole due to external force, the latch 8 drives the connecting rod 7 to move synchronously, the middle position of the locking rod 101 is hinged to the inner wall of the housing, the locking rod 101 can rotate around the inner wall of the housing, a fixing notch 71 is formed in the connecting rod 7, when the latch 8 drives the connecting rod 7 to move synchronously due to external force, the locking rod 101 rotates around the inner wall of the housing, the first end of the locking rod 101 is clamped in the fixing notch 71, and the locking button 4 can be locked (i.e. the locking clamping part 62 is clamped below the connecting rod 7, so that the pressing part 51 is abutted against the contact part 31, thereby allowing the latch 32 to abut against the latch 21 to lock the pull cord 105 at a certain length).

First spring mounting is in the one side of lock rod piece 101 second end, and driving medium 102 slides and establishes at shells inner wall, and, the shaping of the first end of driving medium 102 has slope portion, and the second spring mounting is served at driving medium 102 second, and external force makes driving medium 102 when shells inner wall slides, and slope portion is supporting the opposite side of pressing lock rod piece 101 second end, and then makes the first end joint of lock rod piece 101 be in fixed breach 71, so that pin lock button 4, perhaps, make lock rod piece 101 first end keep away from fixed breach 71, can not pin lock button 4.

When clamping portion 62 does not have the joint when connecting rod 7 below, hasp 8 can't push back, just so avoid not opening the rope lid under the state of locking, when the rope needs to be traded, can only be under the state of clamping portion 62 joint in connecting rod 7 below, just can external force make hasp 8 push back, connecting rod 7 can pin lock button 4 simultaneously, when opening the rope lid, install the second spring of driving medium 102 second end and push forward, make the slope portion of the first end of driving medium 102 support the opposite side of pressing locking lever spare 101 second end, and then make the first end joint of locking lever spare 101 be in fixed breach 71, so that pin lock button 4. Furthermore, the lock catch 8 cannot be pushed forward when the cord cover is opened.

When the haulage rope 105 needs to be changed, when the haulage rope 105 is pulled to finish and can not be pulled again, pin, hasp 8 drives connecting rod 7 and carries out synchronous motion, takes out the rope lid again, twists the rope lock axle out with little cross screwdriver, pulls out haulage rope 105 from the export of leading out at last, can change haulage rope 105, when will installing haulage rope 105, the step with tear haulage rope 105 open just the opposite.

The screw cover 103 is installed between the rotary plate 2 and the inner wall of the housing, and the rotary plate 2 is formed with a fourth hole 22, and a locking recess 1031 is formed at the screw cover 103, and the fixing shaft is passed through the fourth hole 22, and the fixing shaft is made to be locked in the locking recess 1031. In addition, a handle is formed on the shell, so that a person can hold the pet traction device conveniently. A screwdriver 106 and a blade cover shell are installed in the handle, wherein the screwdriver 106 is placed in the blade cover shell.

When the pet traction device is used, the pet traction device comprises a shell, a rotary disc 2, a locking piece 3, a locking button 4 and a first connecting piece 5, wherein a first hole is formed on the shell, the first connecting piece 5 is movably arranged in the first hole, a first end of the first connecting piece 5 is hinged and arranged in the shell, so that the first end of the first connecting piece 5 rotates in the shell, a pressing part 51 is formed at a second end of the first connecting piece 5, in addition, the rotary disc 2 is rotatably arranged in the shell (a clockwork spring and a traction rope 105 are sequentially arranged on the rotary disc 2), a plurality of clamping teeth 21 are uniformly formed at the peripheral edge of the rotary disc 2, the locking piece 3 is hinged and arranged in the shell, so that the locking piece 3 rotates in the shell, a contact part 31 and a clamping tongue 32 are formed on the locking piece 3, wherein the contact part 31 is in contact with the pressing part 51, the clamping tongue 32 is abutted against the clamping teeth 21, the locking button 4 is arranged on the first connecting piece 5, external force is pressed on the lock button 4, so that the lock button 4 is pressed down, at the moment, the lock button 4 supports against the first linking piece 5, so that the first end of the first linking piece 5 rotates in the shell, meanwhile, the pressing part 51 at the second end of the first linking piece 5 moves downwards and supports against the contact part 31, so that the locking piece 3 rotates in the shell, the locking piece 3 in rotation enables the clamping tongue 32 to support against the latch 21 of the turntable 2, and the 'inching' can be realized, so that the situation that when a pet is scared or is prepared to attack other people and runs away suddenly is avoided, the traction rope 105 coiled on the turntable 2 can be pulled out quickly, and the 'inching' can be well prevented that the traction rope 105 coiled on the turntable 2 can be pulled out quickly, and is very safe. The problem that in the prior art, when a pet is frightened or is ready to attack other people and suddenly runs away, the owner cannot pull the pet through the traction device, and safety accidents are easy to happen can be solved.

The above embodiments are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited thereby, and any insubstantial changes and substitutions made by those skilled in the art based on the present invention are within the protection scope of the present invention.

Claims

1. A pet draw gear which characterized in that: comprises a shell, a rotary disc, a locking piece, a locking button and a first connecting piece;

the locking piece is hinged in the shell, so that the locking piece rotates in the shell, a contact part and a clamping tongue are arranged on the locking piece, the contact part is in contact with the pressing part, and the clamping tongue abuts against the clamping teeth;

the locking button is arranged on the first connecting piece, when the locking button is pressed down, the locking button abuts against the first connecting piece, so that the first end of the first connecting piece rotates in the shell, the pressing part moves downwards and abuts against the contact part, the locking piece rotates in the shell, and the clamping tongue abuts against the clamping tooth;

the pet traction device further comprises a second connecting piece, the second connecting piece is located below the first connecting piece, the lock button is provided with a lock column, the first connecting piece is provided with a long circular hole, and the second connecting piece is provided with a second hole and a clamping part;

the lock cylinder penetrates through the long round hole and is inserted into the second hole, so that the lock cylinder drives the second connecting piece to move along the length direction of the long round hole;

the pet traction device also comprises a connecting rod, and the connecting rod is movably arranged in the shell so as to move the connecting rod back and forth in the shell;

external force makes first link up the piece and pushes down and make the lock post drive the second link up the piece and move along the length direction of slotted hole, the portion joint that blocks is in the connecting rod below to make it supports the contact site to push down the portion, and then makes the latch supports the latch.

2. The pet leash device of claim 1, wherein: the shell is provided with a third hole, the third hole is rectangular, one end of the lock catch penetrates through the third hole and is arranged at the first end of the connecting rod, and the first end of the lock catch moves along the length direction of the rectangular third hole;

3. A pet leash as claimed in claim 2, wherein: still include the lock pole piece, lock pole piece middle part position and shells inner wall are articulated each other, the connecting rod is equipped with fixed breach, when the hasp drove the connecting rod and carries out synchronous movement, lock pole piece rotates round shells inner wall, makes the first end joint of lock pole piece is in the fixed breach.

4. A pet leash as claimed in claim 3, wherein: the lock rod piece is characterized by further comprising a first spring, a second spring and a transmission piece, wherein the first spring is arranged on one side of the second end of the lock rod piece, the transmission piece is arranged on the inner wall of the shell in a sliding mode, a slope portion is arranged at the first end of the transmission piece, and the second spring is arranged at the second end of the transmission piece;

when the driving part slides on the inner wall of the shell through external force, the slope part is abutted against the other side of the second end of the locking rod piece, so that the first end of the locking rod piece is clamped in the fixing notch, or the first end of the locking rod piece is far away from the fixing notch.

5. A pet leash device as defined in claim 4, wherein: the rotary cover is arranged between the rotary plate and the inner wall of the shell;

the carousel is equipped with the fourth hole, the spiral cover is equipped with and stops the depressed part, fixed axle passes the fourth hole and the joint is in stop on the depressed part.

6. A pet leash device as defined in claim 5, wherein: the shell is provided with a rope cover, and a guide outlet is formed in the rope cover;

7. A pet leash device as defined in claim 6, wherein: the spring, the connecting buckle, the rope lock shaft and the traction rope are also included;

the first end of the clockwork spring is arranged on the rotary disc, the clockwork spring is wound on the rotary disc, the second end of the clockwork spring is connected with one side of the connecting buckle, the other side of the connecting buckle is connected with the traction rope through the rope lock shaft, namely the second end of the clockwork spring is connected with the first end of the traction rope sequentially through the connecting buckle and the rope lock shaft, and the second end of the traction rope penetrates through the outlet;

8. A pet leash device as claimed in any one of claims 1 to 7, wherein: the shell comprises a first shell and a second shell, and the first shell and the second shell are mutually covered together to form a complete shell.