CN215010351U

CN215010351U - Mobile phone fixing frame

Info

Publication number: CN215010351U
Application number: CN202121317349.XU
Authority: CN
Inventors: 贺秋冬; 胡耀兵; 李望骏; 罗严; 张�浩; 王田
Original assignee: Hubei Engineering University
Current assignee: Hubei Engineering University
Priority date: 2021-06-11
Filing date: 2021-06-11
Publication date: 2021-12-03
Anticipated expiration: 2031-06-11

Abstract

The utility model discloses a mobile phone fixing frame, which comprises a mounting plate, a first clamping component and a second clamping component, wherein the first clamping component comprises two clamping jaws which are arranged on the mounting plate and are spaced along the length direction of the mounting plate, the opposite sides of the two clamping jaws are used for clamping a mobile phone together, and the distance between the two clamping jaws is adjustable; the second centre gripping subassembly includes along the axis rotation installation of up-down downwardly extending extremely the clamping structure of mounting panel lower extreme, clamping structure forms a centre gripping passageway, the centre gripping passageway is used for supplying bicycle handle to wear to establish fixedly. With mobile phone fixing frame monolithic installation on bicycle, the mounting panel with can rotate relatively between the clamping structure, the flexibility is better, and the different bicycle models of adaptation and the cell-phone observation angle of different environment of traveling of being convenient for are through adjusting two distance between the clamping jaw, the centre gripping of the different size specification's of adaptation cell-phone, more convenient reduces the potential safety hazard of the in-process of riding.

Description

Mobile phone fixing frame

Technical Field

The utility model relates to a cell phone stand technical field, in particular to cell phone fixing frame.

Background

With the rising of people's environmental awareness and the investment of commercialization, sharing a single vehicle becomes another way of transportation in cities. However, for a strange city, people often need to use a mobile phone to navigate a road, ride the mobile phone and hold the mobile phone at the same time, so that great potential safety hazards exist, and traffic accidents are easy to happen. Common mobile phone holders can be roughly divided into three types: basic mobile phone holder, supporting mobile phone holder and facial mobile phone holder. The mobile phone fixing support is mainly used for being mounted on a vehicle or indoors, the main structure of a bicycle is a frame, and the common mobile phone fixing support cannot be adapted to the frame and cannot meet the use requirements.

SUMMERY OF THE UTILITY MODEL

The utility model mainly aims at providing a mobile phone fixing frame aims at solving present assembling process, and artifical intensity of labour is big, the problem that production efficiency is low.

In order to achieve the above object, the utility model provides a mobile phone fixing frame, include:

mounting a plate;

the first clamping assembly comprises two clamping jaws which are arranged on the mounting plate and spaced along the length direction of the mounting plate, the opposite side surfaces of the two clamping jaws are used for clamping the mobile phone together, and the distance between the two clamping jaws is adjustable; and the number of the first and second groups,

the second clamping assembly comprises a clamping structure which is rotatably arranged at the lower end of the mounting plate along an axis extending vertically, the clamping structure forms a clamping channel, and the clamping channel is used for the bicycle handle to penetrate and fix.

Optionally, the clamping structure comprises;

the first component is rotatably arranged on the mounting plate along an axis extending in the vertical direction, a first groove is formed in the lower end of the first component, and two opposite side walls of the first groove penetrate through the outer surface of the first component; and the number of the first and second groups,

the second member is detachably mounted to the lower end of the first member, a second groove is formed in the upper end of the second member corresponding to the first groove, and the second groove and the first groove jointly enclose to form the clamping channel.

Optionally, the second clamp assembly further comprises a rotation structure between the mounting plate and the clamp structure, the rotation structure comprising:

the lower end of the base is connected with the clamping structure, a convex shaft is convexly arranged on the upper end surface of the base, and a plurality of arc-shaped grooves are formed in the upper end surface of the base at intervals along the circumferential direction of the convex shaft;

the annular supporting seat is sleeved and installed on the convex shaft, a plurality of positioning rods are arranged on the upper end face of the annular supporting seat at intervals along the circumferential direction of the convex shaft, a plurality of through holes are formed in the upper end face of the annular supporting seat, and the plurality of through holes and the plurality of positioning rods are arranged at intervals;

the top seat is positioned above the annular supporting seat, the upper end of the top seat abuts against the mounting plate, a plurality of positioning grooves are formed in the lower end face of the top seat and correspond to the positioning rods, the positioning grooves are used for the positioning rods to penetrate through, a through hole is formed in the middle of the lower end face of the top seat, and the through hole is sleeved on the protruding shaft;

the balls are movably mounted in the through holes in the vertical direction, and the lower ends of the balls are positioned in the corresponding arc-shaped grooves; and the number of the first and second groups,

a plurality of springs between the plurality of balls and the top mount;

the base and the top seat rotate relatively, so that the balls can selectively move into the corresponding arc-shaped grooves.

Optionally, a first mounting hole is arranged on the upper end surface of the mounting plate in a penetrating manner;

a first threaded hole is formed in the upper end face of the convex shaft in a penetrating mode;

the mobile phone fixing frame further comprises a fixing bolt, and the fixing bolt penetrates through the first mounting hole and is fixed with the first threaded hole in a threaded mode.

Optionally, the clamping structure comprises a first member and a second member which are sequentially connected in an up-down direction, the clamping channel is formed between the first member and the second member, and a second threaded hole is formed in the upper end face of the first member;

the lower end of the fixing bolt sequentially penetrates through the first mounting hole, the first threaded hole and the second threaded hole to be fixed in a threaded mode.

Optionally, each of the jaws comprises:

the supporting block extends along the width direction of the mounting plate and can be movably mounted along the length direction of the mounting plate; and the number of the first and second groups,

and the two clamping arms are arranged on the supporting block at intervals along the width direction of the mounting plate.

Optionally, each of the clamping arms includes a first section inclined from bottom to top toward the mounting plate, and a second section and a third section located at upper and lower ends of the first section, the third section is fixedly mounted on the supporting block, and opposite side surfaces of the third section and the second section are used for abutting against corresponding side surfaces on the mobile phone.

Optionally, a third threaded hole extending along the length direction of the mounting plate penetrates through the side surface of the supporting block in each clamping jaw;

the cell-phone mount still includes adjusting part, the adjusting part package:

the fixing seat is fixedly installed in the middle of the lower end face of the installation plate, and a second installation hole extending along the length direction of the installation plate is formed in the fixing seat;

the rotating rod penetrates through the second mounting hole along the length of the mounting plate, external threads are respectively arranged on parts, extending out of the second mounting hole, of two ends of the rotating rod to form a first thread section and a second thread section, the rotating directions of the first thread section and the second thread section are opposite, and the first thread section and the second thread section respectively penetrate through corresponding third threaded holes; and the number of the first and second groups,

and the two fixing nuts are respectively and fixedly connected with the side ends of the first threaded section and the second threaded section, which extend out of the corresponding third threaded holes.

Optionally, two guide holes extending along the length direction of the mounting plate penetrate through the supporting block in each clamping jaw, and the two guide holes are respectively located at two sides of the third threaded hole;

the adjusting component further comprises two connecting rods, the two connecting rods are fixedly installed on the lower end face of the mounting plate and are arranged at intervals along the width direction of the mounting plate, and two ends of the two connecting rods are movably arranged in the two guide holes of the corresponding supporting blocks in a penetrating mode respectively.

Optionally, an annular groove is respectively formed at one side end of the first thread section and one side end of the second thread section, which are close to each other;

the adjusting component further comprises two elastic retainer rings, the two elastic retainer rings are respectively clamped in the corresponding annular grooves, and one sides, opposite to the elastic retainer rings, of the two elastic retainer rings are respectively contacted with the end parts, corresponding to the fixing seats, of the two elastic retainer rings.

The technical scheme of the utility model, the centre gripping passageway is used for supplying the bicycle handle to wear to establish to with cell-phone mount integral mounting on the bicycle, the mounting panel with can rotate relatively between the clamping structure, the flexibility is better, the different bicycle motorcycle type of adaptation of being convenient for and the cell-phone observation angle of different driving environment, through adjusting two distance between the clamping jaw, the centre gripping of the different size specification's of adaptation cell-phone, more convenient, the user can ride the cell-phone of in-process through this cell-phone mount and settle, convenient navigation reduces the potential safety hazard of the in-process of riding.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.

Fig. 1 is a schematic perspective view of an embodiment (an angle) of a mobile phone fixing frame according to the present invention;

FIG. 2 is a perspective view of an embodiment (at another angle) of the mobile phone holder shown in FIG. 1;

FIG. 3 is an exploded perspective view of the rotary structure of FIG. 1;

fig. 4 is a partial cross-sectional view of the rotating structure of fig. 1.

The reference numbers illustrate:

the objects, features and advantages of the present invention will be further described with reference to the accompanying drawings.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

It should be noted that, if the present invention relates to a directional indication, the directional indication is only used to explain the relative position relationship between the components, the motion situation, etc. in a specific posture, and if the specific posture is changed, the directional indication is changed accordingly.

In addition, if there is a description relating to "first", "second", etc. in the embodiments of the present invention, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions in the embodiments may be combined with each other, but it must be based on the realization of those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should not be considered to exist, and is not within the protection scope of the present invention.

According to the current healthy civilized life style of advocating, "green trip" is one kind and satisfies the energy saving, improves the efficiency, pollution abatement, beneficial health, compromise the trip mode of efficiency, and the bicycle of riding perfectly combines environmental protection and health, as a relatively green trip mode, the sharing bicycle can reduce the influence of human activities to the city. Mobile navigation is increasingly popular with riders because of its portability and timely data update. From observation and comparison, it was found that the need to view the navigation during cycling, particularly for those cycling users who aim at sightseeing, is not negligible. No matter we are walking or riding a bicycle, it is not difficult to find that many people riding the bicycle can control the handlebar with one hand, hold the mobile phone with the other hand, and meanwhile, lower the head to operate the navigation route, which is easy to cause distraction, careless about surrounding traffic and great potential safety hazard of the road. Thus, for an ever-increasing number of bicycles, if a cell phone holder is added, the cost of the improvement would not be too high, but it would greatly increase the safety factor for the user riding the bicycle.

In view of this, the utility model provides a cell phone fixing frame explores and designs a bicycle cell phone stand product that can satisfy user's demand, can realize multiple regulation. Fig. 1 to fig. 4 are embodiments of the mobile phone fixing frame provided by the present invention.

Referring to fig. 1 to 2, the mobile phone fixing frame 100 includes an installation plate 1, a first clamping assembly and a second clamping assembly, the first clamping assembly includes two clamping jaws 21 disposed on the installation plate 1 and spaced along a length direction of the installation plate 1, opposite side surfaces of the two clamping jaws 21 are used for clamping a mobile phone together, and a distance between the two clamping jaws 21 is adjustable; the second centre gripping subassembly includes along the axis rotation installation of up-down downwardly extending extremely the clamping structure of 1 lower extreme of mounting panel, clamping structure forms a centre gripping passageway 3a, centre gripping passageway 3a is used for supplying bicycle handle to wear to establish fixedly.

The technical scheme of the utility model, centre gripping passageway 3a is used for supplying the bicycle handle to wear to establish to with cell-phone mount 100 integral erection on the bicycle, mounting panel 1 with can rotate relatively between the clamping structure, the flexibility is better, the different bicycle motorcycle type of adaptation of being convenient for and the cell-phone observation angle of different driving environment, through adjusting two distance between the clamping jaw 21, the centre gripping of the different size specification's of adaptation cell-phone, more convenient, the user can ride in-process cell-phone through this cell-phone mount 100 and settle, convenient navigation reduces the potential safety hazard of the in-process of riding.

Further, the application does not limit the specific form of the clamping structure clamping the bicycle handle, and the clamping structure may be designed to be a torsion spring cooperating with a claw for clamping and fixing, in this embodiment, the clamping structure includes a first member 31 and a second member 32, the first member 31 is rotatably mounted to the mounting plate 1 along an axis extending in an up-down direction, a first groove 311 is provided at a lower end of the first member 31, and two opposite side walls of the first groove 311 are disposed to penetrate through an outer surface of the first member 31; the second member 32 is detachably mounted to the lower end of the first member 31, a second groove 321 is provided at the upper end of the second member 32 corresponding to the first groove 311, and the second groove 321 and the first groove 311 together enclose the clamping channel 3 a. The first recess 311 with the relative wall of second recess 321 is the arc setting to the structure of the long tube concatenation of adaptation bicycle frame, first component 31 with connect through the bolt and the cooperation of nut between the second component 32, be convenient for install and dismantle, the suitability is good simultaneously.

In addition, the first member 31 is hollow in the middle, so that the weight can be reduced, and the appearance can be improved. Specifically, the radius of the arc of the first groove 311 and the radius of the arc of the second groove 321 are 16mm, and the arc height is 11 mm.

In order to realize the rotational connection between the clamping structure and the mounting plate 1, in an embodiment, a bearing is arranged between the clamping structure and the mounting plate 1, but the rotational friction is small through the bearing connection, the mounting plate 1 may shake or even rotate along with the turning of the vehicle during the riding process, and the stability is poor, in this embodiment, referring to fig. 3 to 4, the second clamping assembly further includes a rotating structure 33 located between the mounting plate 1 and the clamping structure, the rotating structure 33 includes a base 331, an annular supporting seat 332, a top seat 333, a plurality of balls 334 and a plurality of springs 335, the lower end of the base 331 is connected with the clamping structure, a protruding shaft is protruded from the upper end surface of the base 331, and a plurality of arc-shaped grooves 3311 are arranged at intervals along the circumferential direction of the protruding shaft are arranged on the upper end surface of the base 331; the inner hole of the annular supporting seat 332 is sleeved on the protruding shaft, the upper end surface of the annular supporting seat 332 is provided with a plurality of positioning rods 3321 arranged at intervals along the circumferential direction of the protruding shaft, the upper end surface of the annular supporting seat 332 is also provided with a plurality of through holes 3322, and the plurality of through holes 3322 and the plurality of positioning rods 3321 are arranged at intervals; the top seat 333 is located above the annular support seat 332, the upper end of the top seat 333 abuts against the mounting plate 1, a plurality of positioning grooves are formed in the lower end surface of the top seat 333 and correspond to the positioning rods 3321, the positioning grooves allow the positioning rods 3321 to penetrate through, a through hole is formed in the middle of the lower end surface of the top seat 333, and the through hole is sleeved on the protruding shaft; the plurality of balls 334 are movably mounted in the plurality of through holes 3322 in an up-down direction, and the lower ends of the plurality of balls 334 are located in the corresponding arc-shaped grooves 3311; a plurality of springs 335 are disposed between the plurality of balls 334 and the top seat 333 in a one-to-one correspondence; after the components are installed, the spring 335 is always kept in a compressed state in a rotating process, specifically, in an initial state, the ball 334 is always located in a space formed between the through hole 3322 and the arc-shaped groove 3311 under the action of the spring 335, the base 331 and the top seat 333 rotate relatively, at this time, under the cooperation of the positioning rod 3321 and the positioning groove, it is ensured that the annular support drives the spring 335 located in the through hole 3322 to rotate, at this time, since more than half of the volume of the ball 334 is located in the through hole 3322, the ball 334 also rotates along with the through hole, when the ball 334 is separated from the corresponding arc-shaped groove 3311, the compression amount of the spring 335 is increased, at most of the ball 334 moves into another arc-shaped groove 3311, the spring 335 extends, at this time, the ball 334 is clamped and fixed to this position, by setting an angular relationship between the arc-shaped grooves 3311 and the center, namely, the angle of rotation at each time can be controlled, and the mounting plate 1 can be kept fixed when correspondingly positioned in the arc-shaped groove 3311 in each adjusting angle, thereby having better stability.

In this embodiment, four balls 334 and four springs 335 are provided, 4 positioning grooves and 4 positioning rods 3321 are provided, eight arc-shaped grooves 3311 are provided, and the ball 334 is a steel ball and has a diameter of 2.5 mm.

Moreover, a first mounting hole penetrates through the upper end surface of the mounting plate 1; a first threaded hole is formed in the upper end face of the convex shaft in a penetrating mode; the mobile phone fixing frame 100 further comprises a fixing bolt 34, and the fixing bolt 34 penetrates through the first mounting hole to be fixed with the first threaded hole in a threaded manner. Therefore, the fixing bolt 34 can be detachably connected, after the fixing bolt 34 is screwed, the upper end surface of the top seat 333 is abutted against the lower end surface of the mounting plate 1, it needs to be noted that in order to prevent the fixing bolt 34 from protruding out of the mounting plate 1 after being mounted to influence the arrangement of a mobile phone, the first mounting hole is provided with a counter bore.

Besides, the lower end surface of the base 331 is provided with a U-shaped groove for the upper end of the first member 31 to be inserted and positioned, the clamping structure comprises a first member 31 and a second member 32 which are sequentially connected in the vertical direction, the clamping channel 3a is formed between the first member 31 and the second member 32, and the upper end surface of the first member 31 is provided with a second threaded hole; the lower end of the fixing bolt 34 sequentially penetrates through the first mounting hole, the first threaded hole and the second threaded hole to be fixed in a threaded mode. The rotary structure 33 and the first component 31 can be connected simultaneously through the fixing bolt 34, the structural design is more indirect, the mounting mode is simple, the arrangement mode of threaded connection can generate large axial force when threads are screwed down, and meanwhile, the threads can achieve self-locking, so that the manufacturing is easy and the cost is low. The fixing bolt 34 adopted in the utility model is a socket head cap screw.

In order to achieve a more stable handset clamping effect, referring to fig. 2, each clamping jaw 21 includes a supporting block 211 and two clamping arms 212, the supporting block 211 extends along the width direction of the mounting plate 1, and the supporting block 211 can be movably mounted along the length direction of the mounting plate 1; the two clamping arms 212 are arranged on the supporting block 211 at intervals along the width direction of the mounting plate 1. Specifically, each supporting block 211 is located the both sides of mounting panel 1 along its length direction, just the up end of supporting block 211 with the up end parallel and level of mounting panel 1 to guarantee the arrangement plane level of cell-phone, adjust two the activity of supporting block 211 is in order to adjust the distance between the two, provides the width of bigger regulation, two the common centre gripping of support arm can improve the stability of clamping, compares with clamping jaw 21 of single broad, can play the effect that subtracts the weight.

Furthermore, each of the clamping arms 212 includes a first section 212a inclined from bottom to top toward the mounting plate 1, and a second section 212b and a third section 212c located at upper and lower ends of the first section 212a, the third section 212c is fixedly mounted on the supporting block 211, and opposite side surfaces of the third section 212c and the second section 212b are used for abutting against corresponding side surfaces on the mobile phone. The first section 212a, the second section 212b and the third section 212c form a structure similar to an eagle claw, and the gripping effect is better.

In order to realize the movable adjustment of the two supporting blocks 211, a third threaded hole extending along the length direction of the mounting plate 1 is arranged on the side surface of the supporting block 211 in each clamping jaw 21 in a penetrating manner; the mobile phone fixing frame 100 further comprises an adjusting assembly, the adjusting assembly comprises a fixing seat 41, a rotating rod 42 and two fixing nuts 423, the fixing seat 41 is fixedly installed in the middle of the lower end face of the installation plate 1, and a second installation hole extending along the length direction of the installation plate 1 is formed in the fixing seat 41; the rotating rod 42 penetrates through the second mounting hole along the length of the mounting plate 1, external threads are respectively arranged on the parts of the two ends of the rotating rod 42 extending out of the second mounting hole to form a first thread section 421 and a second thread section 422, the rotating directions of the first thread section 421 and the second thread section 422 are opposite, and the first thread section 421 and the second thread section 422 penetrate through the corresponding third threaded holes respectively; the two fixing nuts 423 are respectively and fixedly connected with the side ends of the first threaded hole 421 and the second threaded hole 422, which extend out of the corresponding third threaded holes. By forming the first thread section 421 and the second thread section to form a duplex screw mechanism, specifically, by holding one of the fixing nuts 423 to rotate, the fixing nut 423 drives the rotating rod 42 to rotate synchronously, and due to the opposite thread directions, the two supporting blocks 211 move in opposite directions on the rotating rod 42.

The fixing base 41 may be integrally formed with the mounting plate 1, or may be fixed by welding.

In order to limit each supporting block 211 to have a pure linear motion without rotating along with the rotation of the rotating rod 42, two guide holes extending along the length direction of the mounting plate 1 are formed through the supporting block 211 in each clamping jaw 21, and the two guide holes are respectively located at two sides of the third threaded hole; the adjusting component further comprises two connecting rods 43, the two connecting rods 43 are fixedly mounted on the lower end face of the mounting plate 1 and are arranged at intervals along the width direction of the mounting plate 1, and two ends of the two connecting rods 43 are movably arranged in the two corresponding guide holes of the supporting block 211 in a penetrating mode respectively. The two connecting rods 43 play a role of rotation stopping, and can also support the supporting block 211 to play a role of reinforcement.

In order to prevent the rotating rod 42 from axially shifting relative to the second mounting hole in the adjusting process, annular grooves are respectively formed at the ends of the first threaded section 421 and the second threaded section 422 close to one side; the adjusting assembly further comprises two elastic retainer rings 44, the two elastic retainer rings 44 are respectively clamped in the corresponding annular grooves, and one sides, opposite to the two elastic retainer rings 44, are respectively contacted with the corresponding end portions of the fixed base 41. The two circlips 44 are restricted on both sides, respectively, to fix the axial movement of the rotating rod 42. The problem of because the structure restriction of dwang 42 itself or whole equipment requirement lead to the axle diameter to reduce is solved, the installation and the dismantlement of circlip 44 for the axle are simple and convenient, and the part is lighter and handy, and the volume is littleer to raw and other materials have been saved, the waste has been reduced. Improve production efficiency, reduce labor and material costs, and maintain the integrity of the assembly. The circlip 44 for a shaft may be classified into an eccentric type and a concentric type according to whether the inner diameter and the outer diameter are concentric. The eccentric shaft can be used as a catch to increase the holding force and thus can handle higher thrust loads. The concentric shaft collar may provide more space inside the collar.

The above only be the preferred embodiment of the utility model discloses a not consequently restriction the utility model discloses a patent range, all are in the utility model discloses a conceive, utilize the equivalent structure transform of what the content was done in the description and the attached drawing, or direct/indirect application all is included in other relevant technical field the utility model discloses a patent protection within range.

Claims

1. A mobile phone holder, comprising:

mounting a plate;

2. The handset mount of claim 1, wherein the clamping structure comprises;

3. The handset mount of claim 1 wherein the second clamp assembly further comprises a swivel structure between the mounting plate and the clamp structure, the swivel structure comprising:

a plurality of springs between the plurality of balls and the top mount;

4. The handset fixing frame according to claim 3, wherein the upper end surface of the mounting plate is penetrated with a first mounting hole;

5. The handset fixing frame according to claim 4, wherein the clamping structure comprises a first member and a second member which are sequentially connected in an up-down direction, the clamping channel is formed between the first member and the second member, and a second threaded hole is formed in the upper end surface of the first member;

6. The handset mount of claim 1, wherein each of the jaws comprises:

7. The handset fixing frame according to claim 6, wherein each of the holding arms includes a first section inclined from bottom to top toward the mounting plate, and second and third sections located at upper and lower ends of the first section, the third section is fixedly mounted to the supporting block, and opposite side surfaces of the third section and the second section are used for abutting against corresponding side surfaces on the handset.

8. The handset mounting bracket as claimed in claim 6, wherein a third threaded hole extending along the length direction of the mounting plate is formed through a side surface of the supporting block in each clamping jaw;

the cell-phone mount still includes adjusting part, the adjusting part package:

9. The handset fixing frame according to claim 8, wherein the supporting block of each clamping jaw is provided with two guiding holes extending along the length direction of the mounting plate, and the two guiding holes are respectively positioned at two sides of the third threaded hole;

10. The handset fixing frame according to claim 8, wherein the first thread section and the second thread section are respectively provided with an annular groove at one side end close to the first thread section and the second thread section;