CN219717709U

CN219717709U - Universal insulator clamp

Info

Publication number: CN219717709U
Application number: CN202122714131.4U
Authority: CN
Inventors: 韩玲玲; 李倩; 吴晓辉; 范瑞妮; 徐毅端; 雪占波
Original assignee: Baoji West Electrification Co ltd
Current assignee: Baoji West Electrification Co ltd
Priority date: 2021-11-08
Filing date: 2021-11-08
Publication date: 2023-09-19
Anticipated expiration: 2031-11-08

Abstract

The utility model provides a general insulator fixture, be equipped with a plurality of flexible axles along the hoop in annular card body outside, and realize the synchronous regulation of a plurality of regulation drive arrangement behind the worm in the worm gear mechanism of a plurality of regulation drive arrangement through the coaxial flexible axle, be equipped with a plurality of clamping heads of being connected through elastic connection subassembly with the regulation drive arrangement of corresponding position department on the annular card body pore wall, and clamping head realizes the clamp to insulator steel cap under the drive of regulation drive arrangement, be equipped with on the annular card body with clamping chuck adaptation be connected and be used for carrying out spacing stop device to clamping head expansion limit position. The utility model optimizes the mounting structure of the clamping head and the annular card body, provides a reliable telescopic structure for the clamping head, ensures that the clamping head is effectively contacted with the insulator steel cap, ensures that the clamping head reliably clamps the insulator steel cap, simultaneously improves the stability and the reliability of the telescopic structure of the clamping head, and meets the replacement requirements of insulators of different models, different manufacturers and different batches.

Description

Universal insulator clamp

Technical Field

The utility model belongs to the technical field of insulator replacement, and particularly relates to a universal insulator fixture.

Background

Replacement of damaged insulators is an important task for maintenance of ultra-high voltage transmission lines. When the insulator on the transmission line is replaced, due to the complexity of the size of the insulator steel cap applied at present, corresponding tools are prepared by considering factors such as different types, different manufacturers, even different batches, and the like, when the carried tools are not consistent with the specification and the size of the replaced insulator, the replacement operation cannot be performed, the operation can be continued after waiting for the available type clamps in place, the conditions of time and labor waste occur, and the construction period is delayed and the manpower resource is wasted. In this situation, a high requirement is placed on the preparation work of the earlier stage of the operation, and the manufacturing and management cost of a large number of fixtures is also difficult to bear; the currently applied clamps mainly comprise clamps suitable for insulators with single sizes and clamps with replaceable bayonets, but the clamps have the defects; in addition, the clamping device can be used for replacing clamps of various types at present, the clamping devices are respectively adjusted through screws to adapt to the change of the sizes of the steel caps, the steps of respectively adjusting the clamping devices are complex, the running synchronism of the clamping devices is low, and the clamping devices are prone to being unbalanced and damaged.

In the patent number 201721137817.9, the patent name is a manual clamping head synchronous adjustable insulator replacing device (hereinafter referred to as a comparison document), a clamping device structure with stronger universality is disclosed, the replacement of insulators of different types and different manufacturers even in different batches can be realized, two connected adjustable telescopic clamping devices are connected through a flexible shaft, synchronous control of clamping pieces in a plurality of adjustable telescopic clamping devices can be realized through rotating hexagon head screws in any adjustable telescopic clamping device, clamping or loosening of insulators can be completed, the clamping pieces are hinged to the clamping devices, the clamping pieces hinged to one side are pressed down through a pressing screw to clamp an insulator steel cap, the universality of the clamping devices is improved, but the position of a pressing bolt for driving the clamping pieces to rotate is not provided with a limiting structure, the risk that a spring for pulling the clamping pieces to reset has a stretching length exceeding a limiting length exists due to improper operation exists.

Disclosure of Invention

The utility model solves the technical problems that: the utility model provides a general insulator fixture, optimize the mounting structure of card chuck and annular card body, adopt elastic connection subassembly with clamping head elastic mounting in annular card body and link firmly with adjusting drive device, for clamping head provides reliable extending structure, guarantee card chuck and insulator steel cap effective contact, and set up the stop device who is used for carrying out spacing to clamping head flexible extreme position on annular card body, when guaranteeing card chuck to the reliable centre gripping of insulator steel cap, improve card chuck extending structure's stable reliability, satisfy different models, different producer and different batch insulator change demand, the commonality is strong.

The utility model adopts the technical scheme that: the utility model provides a general insulator fixture, includes two ring-shaped card bodies that parallel alignment set up and the turn-buckle of connecting two ring-shaped card bodies, ring-shaped card body circumference is equipped with a plurality of regulation drive arrangement, ring-shaped card body outside is equipped with a plurality of flexible axles along the hoop, and realizes the synchronous regulation of a plurality of regulation drive arrangement after the worm in a plurality of regulation drive arrangement's worm gear worm mechanism links firmly through the flexible axle is coaxial, be equipped with a plurality of clamping heads of being connected through elastic connection subassembly with the regulation drive arrangement of corresponding position department on the ring-shaped card body pore wall, and clamping head realizes the clamp to insulator steel cap under the drive of regulation drive arrangement, be equipped with on the ring-shaped card body with clamping head adaptation be connected and be used for carrying out spacing stop device to clamping head expansion limit position.

The clamping head is of an integrated structure formed by an inner circular arc clamping plate and a square block at the middle part of the outer wall of one end of the circular arc clamping plate, the square block is inserted into a rectangular groove on the inner wall of the annular clamping body, the elastic connecting assembly comprises an inner hexagonal cylindrical head screw and a reset spring, a stepped hole is formed in the middle part of the clamping head, the inner hexagonal cylindrical head screw arranged in the stepped hole extends out of the stepped hole to be fixedly connected with a shell thread of the adjusting driving device, and the reset spring sleeved on the inner hexagonal cylindrical head screw is positioned between the stepped surface of one end of the stepped hole and the head of the inner hexagonal cylindrical head screw and is compressed when the adjusting driving device drives the clamping head to move towards the center direction of the annular clamping body.

Further, stop device includes cylinder end holding screw, system has the screw hole with rectangular channel intercommunication on the annular card body lateral wall, and cylinder end holding screw and screw hole adaptation are connected, with system has the direction constant head tank on the clamping head lateral wall of cylinder end holding screw homonymy, in the cylinder end of cylinder end holding screw stretches into the direction constant head tank, regulation drive arrangement drive clamping head moves to cylinder end holding screw and direction constant head tank top surface contact to annular card body central direction, or reset spring pulling clamping head resets and moves to cylinder end holding screw and direction constant head tank bottom groove surface contact after, realizes the spacing to clamping head withdrawal or stretching out extreme position.

Further, a tightener is arranged between two ends of the annular clamp bodies, the tightener comprises a hydraulic screw and a stress application handle, two ends of the hydraulic screw are connected with two ends of the annular clamp bodies through pins respectively, one end of the stress application handle is hinged with the hydraulic screw shell, and the other end of the stress application handle forms a manual pressurizing end of a labor-saving lever after the near end of the stress application handle is hinged with a hydraulic screw pressurizing rod.

Further, the annular clamp body is formed by butt joint of two ends of an upper cover and a lower cover with arc structures, one ends of the upper cover and the lower cover are hinged, and the other ends of the upper cover and the lower cover are detachably and fixedly connected, so that a hole for inserting an insulator steel cap is formed in the middle after the upper cover and the lower cover are buckled; the annular clamp body is provided with a protection device which is matched with the flexible shaft; the protection device comprises a supporting seat and a protection supporting sheet metal, wherein the supporting seat is an L-shaped plate, one end plate of the supporting seat is fixed on an upper cover, a flexible shaft which is connected with two adjacent adjusting driving devices is matched in an arc-shaped groove at the upper end of the other end plate of the supporting seat, the protection supporting sheet metal is formed by a U-shaped groove plate with a horizontal bottom and inclined plates which are externally expanded on two sides through arc transition connection, two ends of the protection supporting sheet metal are respectively connected with the adjusting driving devices which are correspondingly positioned on the lower cover through bolts in a fixed manner, and flexible shafts which are used for connecting two adjacent adjusting driving devices are matched in the U-shaped groove of the protection supporting sheet metal are positioned in the U-shaped groove surface of the protection supporting sheet metal by a notch towards the U-shaped groove surface of the protection supporting sheet metal and are fixed in noise reduction sponge in the U-shaped groove of the protection supporting sheet metal through bolts on two side inner walls of the middle part of the protection supporting sheet metal.

Compared with the prior art, the utility model has the advantages that:

1. according to the technical scheme, the mounting structure of the clamp head and the annular card body is optimized, the clamp head is elastically mounted in the annular card body by adopting the elastic connection assembly and fixedly connected with the adjusting driving device, the clamp head stretches along the central direction of the annular card body, a reliable stretching structure is provided for the clamp head, the clamp head is ensured to be in effective contact with the insulator steel cap, and the reliability of the clamping effect is improved;

2. according to the technical scheme, the limiting device for limiting the telescopic limit position of the clamping head is arranged on the annular clamping body, so that the clamping head is ensured to reliably clamp the insulator steel cap, meanwhile, the stability and reliability of the telescopic structure of the clamping head are improved, the working structure of the reset spring is optimized, and the service life and reliability are prolonged;

3. according to the technical scheme, the protection device matched with the flexible shaft is arranged on the periphery of the annular clamp body, so that the flexible shaft is supported and protected, and meanwhile, vibration noise of a universal joint in the flexible shaft during rotation can be reduced;

4. the technical scheme has the advantages of simple structure, convenient and reliable use, strong universality and capability of meeting the insulator replacement requirements of different models, different manufacturers and different batches.

Drawings

FIG. 1 is a schematic diagram of the structure of the present utility model;

FIG. 2 is a schematic view of the connection of the annular card body, the adjustment drive device, the flexible shaft and the clip head of the present utility model;

FIG. 3 is a schematic view of the connection structure of the annular card body, the adjustment driving device, the clip head and the limiting device of the present utility model;

FIG. 4 is a schematic perspective view of the annular card body of the present utility model;

fig. 5 is a schematic view of a three-dimensional structure of a protective support sheet metal according to the present utility model.

Detailed Description

An embodiment of the present utility model will now be described, with reference to fig. 1-5, so that the technical solutions will be clearly and fully described, it being apparent that the described embodiments are only some, but not all, embodiments of the present utility model.

In the description of the present utility model, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "top," "bottom," "inner," "outer," and the like indicate or are based on the orientation or positional relationship shown in the drawings, merely to facilitate description of the present utility model and to simplify the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be construed as limiting the present utility model.

The universal insulator clamp is shown in fig. 1, and comprises two annular clamp bodies 1 which are arranged in parallel and aligned, and a wire tightener 2 which connects the two annular clamp bodies 1, wherein a plurality of adjusting driving devices 13 are circumferentially arranged on the annular clamp bodies 1, a plurality of flexible shafts 14 are circumferentially arranged on the outer sides of the annular clamp bodies 1, the worms in worm and gear mechanisms of the plurality of adjusting driving devices 13 are fixedly connected through the flexible shafts 14 to realize synchronous adjustment of the plurality of adjusting driving devices 13, a plurality of clamping heads 3 which are connected with the adjusting driving devices 13 at corresponding positions through elastic connecting assemblies are arranged on the hole walls of the annular clamp bodies 1, and the clamping heads 3 clamp insulator steel caps under the driving of the adjusting driving devices 13, and limiting devices which are adaptively connected with the clamping heads 3 and are used for limiting the telescopic limiting positions of the clamping heads 3 are arranged on the annular clamp bodies 1; in the structure, the mounting structure of the clamp head 3 and the annular card body 1 is optimized, the clamp head 3 is elastically mounted in the annular card body 1 by adopting the elastic connecting component and fixedly connected with the adjusting driving device 13, so that the clamp head 3 stretches along the central direction of the annular card body 1, a reliable stretching structure is provided for the clamp head 3, the clamp head 3 is ensured to be in effective contact with the insulator steel cap, and the reliability of the clamping effect is improved;

as shown in fig. 2, the specific shape and resilient mounting structure of the clip head 3 is as follows: the clamping head 3 is of an integrated structure composed of an inner circular arc clamping plate 3-1 and a square block 3-2 in the middle of the outer wall of one end of the circular arc clamping plate 3-1, the square block 3-2 is inserted into a rectangular groove 4 on the inner wall of the annular clamping body 1, the elastic connecting assembly comprises an inner hexagonal cylindrical head screw 5 and a reset spring 6, a stepped hole 7 is formed in the middle of the clamping head 3, the inner hexagonal cylindrical head screw 5 arranged in the stepped hole 7 extends out of the stepped hole 7 and is fixedly connected with a shell of the adjusting driving device 13 through threads, and the reset spring 6 sleeved on the inner hexagonal cylindrical head screw 5 is positioned between the stepped surface of one end of the stepped hole 7 and the head of the inner hexagonal cylindrical head screw 5 and is compressed when the adjusting driving device 13 drives the clamping head 3 to move towards the center direction of the annular clamping body 1.

The structure of the adjusting driving device 13 is in the prior art, namely, the right end of the worm is controlled to rotate around the shaft, the worm wheel drives the screw rod to rotate through key connection, when the screw rod is in right rotation, the screw rod is screwed in to push the clamping head 3 to radially shrink, the square block 3-2 of the clamping head 3 slides in the rectangular groove 4, and the reset spring 6 is compressed until the inner hexagonal cylinder end set screw 8 is limited; when the screw rod rotates leftwards, the screw rod rotates out, the clamping head 3 is reset and opened under the action of the reset spring 6, and the square block 3-2 of the clamping head 3 slides in the rectangular groove 4 until the inner hexagonal cylinder end set screw 8 is limited; the flexible shaft 14 is composed of an outer spring protection sleeve and a mandrel in the spring protection sleeve, wherein the mandrel is of a structure formed by connecting a plurality of universal joints, one-point driving three-point linkage is realized, and the uniformly distributed three clamping heads 3 are simultaneously tightened or simultaneously opened.

As shown in fig. 3, the specific structure of the limiting device is as follows: the limiting device comprises a cylindrical end set screw 8, a threaded hole communicated with the rectangular groove 4 is formed in one side wall of the annular clamp body 1, the cylindrical end set screw 8 is connected with the threaded hole in an adaptive manner, a guide positioning groove 9 is formed in the side wall of the clamp head 3 on the same side with the cylindrical end set screw 8, the cylindrical end of the cylindrical end set screw 8 stretches into the guide positioning groove 9, the adjusting driving device 13 drives the clamp head 3 to move towards the center direction of the annular clamp body 1 until the cylindrical end set screw 8 contacts with the top groove surface of the guide positioning groove 9, or after the reset spring 6 pulls the clamp head 3 to reset until the cylindrical end set screw 8 contacts with the bottom groove surface of the guide positioning groove 9, limiting of stretching or retracting the limit position of the clamp head 3 is achieved; in the structure, the limiting device for limiting the telescopic limit position of the clamp head 3 is arranged on the annular clamp body 1, so that the clamp head 3 can reliably clamp the insulator steel cap, the stability and reliability of the telescopic structure of the clamp head 3 are improved, the working structure of the reset spring 6 is optimized, and the service life and reliability are prolonged;

the specific structure of the tightener 2 is as follows: a wire tightener 2 is arranged between the two end parts of the two annular clamp bodies 1, the wire tightener 2 comprises a hydraulic lead screw 2-1 and a force-applying handle 2-2, the two ends of the hydraulic lead screw 2-1 are respectively connected with the end parts of the two annular clamp bodies 1 through pins, one end part of the force-applying handle 2-2 is hinged with a shell of the hydraulic lead screw 2-1, and a near end part of the force-applying handle 2-2 is hinged with a pressurizing rod of the hydraulic lead screw 2-1, and then the other end of the force-applying handle 2-2 forms a manual pressurizing end of a labor-saving lever; the stressing handle 2-2 of the hydraulic lead screw 2-1 is pressed to manually stress so that the two annular clamp bodies 1 are axially tightened, thereby axially tightening the two insulators clamped by the closed clamp, and then replacing the insulator with the middle insulator to be replaced; opening a deflation valve of the hydraulic lead screw 2-1 to axially extend the hydraulic lead screw 2-1, and disassembling the closed clamp after the clamp is not subjected to axial tension to finish insulator replacement;

as shown in fig. 4, the specific structure of the annular card body 1 is as follows: the annular clamp body 1 is formed by butt joint of two ends of an upper cover 1-1 and a lower cover 1-2 of an arc structure, one end of the upper cover 1-1 is hinged with one end of the lower cover 1-2, and the other end of the upper cover 1-1 is detachably and fixedly connected with the other end of the lower cover 1-2, so that a hole for inserting an insulator steel cap is formed in the middle after the upper cover 1-1 and the lower cover 1-2 are buckled; the annular clamp body 1 is provided with a protection device which is matched with the flexible shaft 14;

the specific structure of the protection device is as follows: the protection device comprises a support seat 10 and a protection support sheet metal 11, wherein the support seat 10 is an L-shaped plate, one end plate of the support seat 10 is fixed on the upper cover 1-1, a flexible shaft 14 connected with two adjacent adjustment driving devices 13 on the upper cover 1-1 and the lower cover 1-2 is adapted to an arc-shaped groove at the upper end of the other end plate of the support seat 10, the function of supporting one part of the flexible shaft 14 is achieved, and vibration noise is reduced; as shown in fig. 5, the protection support metal plate 11 is formed by connecting a U-shaped groove plate with a horizontal bottom and inclined plates with two outward-expanded sides through arc transition, two ends of the protection support metal plate 11 are respectively and fixedly connected with the adjusting driving devices 13 at corresponding positions on the lower cover 1-2 through bolts, flexible shafts 14 for connecting two adjacent adjusting driving devices 13 on the lower cover 1-2 are adapted to the U-shaped grooves of the protection support metal plate 11, and the flexible shafts 14 are positioned in noise reduction sponge in the U-shaped grooves of the protection support metal plate 11 by the protection metal plate 12 which faces the U-shaped groove surfaces of the protection support metal plate 11 through the grooves and is fixed on the inner walls of two sides of the middle part of the protection support metal plate 11 through bolts; in the structure, the protective supporting metal plate 11 matched with the flexible shaft 14 is arranged on the periphery of the annular clamp body 1, and noise-reducing sponge is additionally arranged on the inner wall of the U-shaped groove of the protective supporting metal plate 11 and the bottom of the groove, so that the flexible shaft 14 is supported and protected, and meanwhile, the vibration noise of the universal joint in the flexible shaft 14 during rotation can be reduced;

in the technical scheme, the annular card body 1 at the front end of the universal insulator and the other annular card body 1 at the rear end of the universal insulator are different in stress form, so that the clamping heads 3 (tensile force) in the annular card body 1 at the front end are different from the clamping heads 3 (compressive force) in the annular card body 1 at the rear end only in form and structure of the part contacted with the insulator, and the rest parts are the same; the scheme has the advantages of simple structure, convenient and reliable use, strong universality and capability of meeting the insulator replacement requirements of different models, different manufacturers and different batches.

It will be evident to those skilled in the art that the utility model is not limited to the details of the foregoing illustrative embodiments, and that the present utility model may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the utility model being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Furthermore, it should be understood that although the present disclosure describes embodiments, not every embodiment is provided with a separate embodiment, and that this description is provided for clarity only, and that the disclosure is not limited to the embodiments described in detail below, and that the embodiments described in the examples may be combined as appropriate to form other embodiments that will be apparent to those skilled in the art.

Claims

1. The utility model provides a general insulator fixture, includes annular card body (1) that two parallels set up and with turn-buckle (2) that two annular card bodies (1) are connected, annular card body (1) circumference is equipped with a plurality of regulation drive arrangement (13), annular card body (1) outside is equipped with a plurality of flexible axle (14) along the hoop, and the worm in the worm gear mechanism of a plurality of regulation drive arrangement (13) realizes the synchronous regulation of a plurality of regulation drive arrangement (13) after passing through flexible axle (14) coaxial fixedly connection, its characterized in that: the device is characterized in that a plurality of clamping heads (3) connected with adjusting driving devices (13) at corresponding positions through elastic connection assemblies are arranged on the hole wall of the annular card body (1), the clamping heads (3) are used for clamping insulator steel caps under the driving of the adjusting driving devices (13), and limiting devices which are connected with the clamping heads (3) in an adaptive mode and used for limiting the telescopic limiting positions of the clamping heads (3) are arranged on the annular card body (1).

2. The universal insulator clip of claim 1, wherein: the clamping head (3) is of an integrated structure formed by an inner circular arc clamping plate (3-1) and a square block (3-2) arranged in the middle of the outer wall of one end of the circular arc clamping plate (3-1), the square block (3-2) is inserted into a rectangular groove (4) on the inner wall of the annular clamping body (1), the elastic connecting assembly comprises an inner hexagonal cylindrical head screw (5) and a reset spring (6), a stepped hole (7) is formed in the middle of the clamping head (3), the inner hexagonal cylindrical head screw (5) arranged in the stepped hole (7) extends out of the stepped hole (7) and is fixedly connected with a shell of the adjusting driving device (13) in a threaded mode, and the reset spring (6) sleeved on the inner hexagonal cylindrical head screw (5) is located between the stepped surface of one end of the stepped hole (7) and the head of the inner hexagonal cylindrical head screw (5) and is compressed when the adjusting driving device (13) drives the clamping head (3) to move towards the center of the annular clamping body (1).

3. The universal insulator clip of claim 2, wherein: the limiting device comprises a cylindrical end set screw (8), a threaded hole communicated with the rectangular groove (4) is formed in one side wall of the annular clamp body (1), the cylindrical end set screw (8) is connected with the threaded hole in an adaptive mode, a guide positioning groove (9) is formed in the side wall of the clamp head (3) on the same side of the cylindrical end set screw (8), the cylindrical end of the cylindrical end set screw (8) stretches into the guide positioning groove (9), the adjusting driving device (13) drives the clamp head (3) to move to the center direction of the annular clamp body (1) to enable the cylindrical end set screw (8) to be in surface contact with the top groove of the guide positioning groove (9), or a reset spring (6) pulls the clamp head (3) to reset to enable the cylindrical end set screw (8) to be in surface contact with the bottom groove of the guide positioning groove (9), and limiting of retraction or extension of the clamp head (3) is achieved.

4. The universal insulator clip of claim 1, wherein: the two annular clamp bodies (1) are respectively provided with a tightener (2) between two end parts, the tightener (2) comprises a hydraulic screw (2-1) and a stress application handle (2-2), two ends of the hydraulic screw (2-1) are respectively connected with the end parts of the two annular clamp bodies (1) through pins, one end part of the stress application handle (2-2) is hinged with a shell of the hydraulic screw (2-1), and the near end part of the stress application handle (2-2) is hinged with a pressurizing rod of the hydraulic screw (2-1) to form a manual pressurizing end of a labor-saving lever at the other end of the stress application handle (2-2).

5. The universal insulator clip of any one of claims 1-4, wherein: the annular clamp body (1) is formed by butt joint of two ends of an upper cover (1-1) and a lower cover (1-2) with arc structures, one ends of the upper cover (1-1) and the lower cover (1-2) are hinged, and the other ends of the upper cover and the lower cover (1-2) are detachably and fixedly connected, so that a hole for inserting an insulator steel cap is formed in the middle after the upper cover (1-1) and the lower cover (1-2) are buckled; the annular clamp body (1) is provided with a protection device which is matched with the flexible shaft (14); the protection device comprises a supporting seat (10) and a protection supporting metal plate (11), the supporting seat (10) is an L-shaped plate, one end plate of the supporting seat (10) is fixed on an upper cover (1-1), two adjacent adjusting driving devices (13) on the upper cover (1-1) and a lower cover (1-2) are connected with each other, a flexible shaft (14) is adapted to an arc-shaped groove at the upper end of the other end plate of the supporting seat (10), the protection supporting metal plate (11) is formed by connecting a U-shaped groove plate with two outwards-expanded inclined plates in an arc transition mode, two ends of the protection supporting metal plate (11) are fixedly connected with the adjusting driving devices (13) at corresponding positions on the lower cover (1-2) through bolts, the flexible shafts (14) for connecting the two adjacent adjusting driving devices (13) on the lower cover (1-2) are adapted to the U-shaped groove of the protection supporting metal plate (11), and the U-shaped groove faces of the protection supporting metal plate (11) are fixed to the U-shaped groove faces of the protection supporting metal plate (11) through bolts, and the protection groove is positioned in the U-shaped flexible shaft (12) of the protection metal plate (11) on the inner wall of the middle of the protection supporting metal plate.