CN215869318U

CN215869318U - Full-automatic feeding machine for solar panel wiring junction box

Info

Publication number: CN215869318U
Application number: CN202121499463.9U
Authority: CN
Inventors: 李藏珍; 李俊娥; 赵亚锋
Original assignee: Suzhou Louge Automation Technology Co ltd
Current assignee: Suzhou Louge Automation Technology Co ltd
Priority date: 2021-07-02
Filing date: 2021-07-02
Publication date: 2022-02-18
Anticipated expiration: 2031-07-02

Abstract

The utility model relates to a full-automatic feeding machine for a solar panel wired junction box, which comprises a rack, a drum type bin, two limiting plates, an interval adjusting assembly, a material detecting assembly, a height adjusting assembly, a material stirring assembly and a material blocking assembly, wherein the two ends of the drum type bin are rotatably arranged on the rack, a discharging end of the drum type bin penetrates through the rack; the drum-type storage bin is provided with a wire guide groove arranged along the length direction of the drum-type storage bin; the utility model is not only suitable for various types of wired junction boxes, but also can monitor the number and the positions of the wired junction boxes in the drum-type storage bin in real time, and has the advantages of small volume, large storage capacity, convenient operation and the like.

Description

Full-automatic feeding machine for solar panel wiring junction box

Technical Field

The utility model relates to the technical field of solar panel production, in particular to a full-automatic feeding machine for a solar panel wiring junction box.

Background

With the rapid development of the field of solar panels, the application of the market to the solar panels is more and more extensive, so that the use amount of the solar panels is also sharply increased.

According to the solar photovoltaic module with the three junction box laminated structure disclosed by the prior art 201420150552.6, the back plate is provided with the three junction boxes, the junction boxes on two sides are provided with wires, the junction box in the middle is provided with no wires, the wires are wound in a disordered manner and are difficult to separate due to the fact that the junction boxes are irregular in appearance and a plurality of junction boxes are put together, and the junction boxes of solar cell panels of different models are different in specification, so that the junction boxes are automatically stored, fed and picked up by a robot, and great difficulty is brought.

Although a solar panel junction box feeding device also appears in the market, for example, an automatic solar cell module junction box feeding device and a fixture matched with the feeding device disclosed in the prior art 201710846073.6 comprise an upper layer storage bin and a lower layer storage bin, wherein each layer of storage bin is respectively provided with A, B, C, D four sections of storage areas; each storage area can store a plurality of junction boxes, when the junction boxes in the section A of the storage area of the upper storage device are used up, the rotating device automatically rotates by 90 degrees, the junction boxes are converted into the section B of the storage area to continuously provide the junction boxes for the multi-axis robot, and the like, all the junction boxes in the four sections A, B, C, D of the upper storage area are used up, the multi-axis robot is converted into the junction boxes stored by the lower storage bin, and continuous automatic feeding is realized; however, there are the following problems: 1. the automatic feeding of the junction boxes of a single model can be realized, the use is limited, and different feeding devices are needed when the junction boxes of different models are fed, so that the production cost is greatly increased; 2. four sections of storage areas of each layer of storage bin are distributed in a cross shape and need to be driven by a rotating device, so that the storage bin is large in size, complex in structure and limited in the number of stored junction boxes.

SUMMERY OF THE UTILITY MODEL

The utility model aims to overcome the defects of the prior art and provide a full-automatic feeding machine for a solar panel wiring junction box.

In order to achieve the purpose, the utility model adopts the technical scheme that: a full-automatic feeding machine for a solar panel wiring box comprises a rack, a drum type bin with two ends rotatably arranged on the rack and a discharging end penetrating through the rack, two limiting plates vertically arranged in the drum type bin and a discharging end penetrating through the rack, an interval adjusting component arranged on the rack and used for adjusting the interval between the two limiting plates, a material detecting component arranged in the rack and used for detecting the number and the position of the wiring box in the two limiting plates, a height adjusting component arranged on the rack and used for adjusting the height of the material detecting component, a material stirring component arranged on one side of the rack and used for driving the wiring box in the drum type bin to move towards the discharging end, and a material blocking component arranged at the discharging end of the two limiting plates; the drum-type storage bin is provided with a wire guide groove arranged along the length direction of the drum-type storage bin.

Preferably, the distance adjusting components are respectively arranged on the distance adjusting execution units at two ends of the rack, the adjusting rods are rotatably arranged on the rack and placed along the length direction of the rack, and the two groups of distance adjusting connecting rod units are respectively arranged on the adjusting rods and are respectively used for driving the distance adjusting execution units;

each group of the spacing adjustment execution units comprises a guide rail horizontally arranged at the end part of the rack and two translation sliding seats which are arranged on the guide rail in a sliding manner and are respectively positioned at two sides of the adjusting rod;

each group of the distance adjusting connecting rod units comprises a connecting block arranged on the adjusting rod and two distance adjusting connecting rods, wherein two ends of each distance adjusting connecting rod are respectively hinged with the connecting block and the translation sliding seat;

one end of the adjusting rod, which is positioned at the feeding end, is provided with an adjusting block fixed with the frame through a bolt;

the two limiting plates are respectively arranged on the translation sliding seat.

Preferably, the height adjusting assembly comprises guide rail units respectively vertically arranged at two ends of the rack, lifting rods arranged below the adjusting rods and with two ends respectively connected with the guide rail units, adjusting plates arranged above the adjusting rods and placed in parallel with the adjusting rods, and a plurality of groups of height adjusting connecting rod units arranged on the adjusting plates and used for driving the material detecting assembly to lift;

each group of height adjusting connecting rod units comprises a sliding block arranged on the adjusting rod in a sliding mode, a fixed block fixedly arranged on the lifting rod and a height adjusting connecting rod, wherein two ends of the height adjusting connecting rod are respectively hinged with the sliding block and the fixed block;

the adjusting plate is respectively connected with the sliding blocks of the multiple groups of height adjusting connecting rod units, and a positioning plate fixed with the rack through bolts is arranged at one end of the feeding plate.

Preferably, the material detection assembly comprises a supporting plate, a plurality of signal acquisition plates and a plurality of detection units, wherein the supporting plate is arranged below the lifting rod and connected with fixing blocks in the plurality of groups of height adjusting connecting rod units; each group of detection units comprises a groove-shaped photoelectric sensor arranged on the signal acquisition board and an induction sheet which is rotatably arranged on the supporting board and the top of the induction sheet is positioned in a groove of the groove-shaped photoelectric sensor.

Preferably, the material stirring assembly comprises a sliding rail arranged on one side of the rack and placed along the length direction of the rack, a sliding plate arranged on the sliding rail in a sliding mode, a belt transmission arranged on one side of the rack and used for driving the sliding plate, a rotary cylinder arranged on the sliding plate and located on one side of the drum-type stock bin, a material stirring frame arranged at the driving end of the rotary cylinder, and two material stirring rods arranged on the material stirring frame and capable of stretching into the drum-type stock bin.

Preferably, the material blocking assembly comprises material blocking frames respectively arranged at the discharge ends of the two limiting plates, stop blocks respectively arranged at the inner sides of the two material blocking frames, and a sensor for detecting whether a junction box exists.

Preferably, the drum-type storage bin comprises annular cover plates arranged at two ends of the frame respectively, a plurality of fixing rods used for connecting the two annular cover plates, and positioning blocks arranged on the annular cover plates and capable of being fixed at the end parts of the wired supports through screws; the annular cover plate is provided with an opening through which a wire on the wired junction box can conveniently pass; and the two annular cover plates are respectively provided with a material guide rod on two sides of the opening to form a wire guide groove.

Preferably, the rack comprises two mounting plates which are arranged in parallel and a connecting column for connecting the two mounting plates; circular openings which are oppositely arranged are respectively arranged on the two mounting plates, and arc-shaped grooves are respectively arranged on the outer side surfaces of the two mounting plates; the back surface of each annular cover plate is provided with an arc-shaped guide sheet positioned in the arc-shaped groove, and arc-shaped connecting parts are respectively arranged on the two sides of the opening on the back surface of each annular cover plate; the arc connecting portion are located circular opening, be provided with the leading wheel of a protrusion mounting panel medial surface on the arc connecting portion at least.

Due to the application of the technical scheme, compared with the prior art, the utility model has the following advantages:

1. according to the utility model, the position of the wire guide groove can be adjusted by rotating the drum-type storage bin, and the distance between the two limiting plates can be respectively adjusted by the distance adjusting assembly, so that the wire guide device is suitable for various types of wired junction boxes, and the production cost is greatly reduced;

2. the quantity and the position of the wired junction boxes in the drum-type storage bin can be monitored in real time through the material detection assembly, so that automatic control is facilitated;

3. the utility model is strip-shaped, not only has small volume and large storage capacity, but also is convenient to operate.

Drawings

The technical scheme of the utility model is further explained by combining the accompanying drawings as follows:

FIG. 1 is a schematic structural view of a full-automatic feeding machine for a solar panel wired junction box, which is disclosed by the utility model;

FIG. 2 is a schematic structural view of a spacing adjustment assembly according to the present invention;

FIG. 3 is an enlarged view of a portion of FIG. 2 at A;

FIG. 4 is a schematic structural view of a material detection assembly and a height adjustment assembly according to the present invention;

FIG. 5 is an enlarged view of a portion of FIG. 4 at B;

FIG. 6 is a schematic structural diagram of a detection unit according to the present invention;

FIG. 7 is a schematic structural view of a kickoff assembly of the present invention;

FIG. 8 is an end view of the feeding end of the full-automatic feeder for the solar panel wired junction box according to the present invention;

FIG. 9 is a schematic structural view of a drum-type bunker in accordance with the present invention;

FIG. 10 is an enlarged view of a portion of FIG. 9 at C;

fig. 11 is a schematic structural view of the annular cover plate of the present invention.

Wherein: 1. a frame: 11. mounting a plate: 12. connecting a column: 13. circular opening: 14. an arc-shaped slot; 2. a drum-type stock bin; 21. a wire guide groove; 22. an annular cover plate; 23. fixing the rod; 24. positioning blocks; 25. an opening; 26. a material guiding rod; 27. an arc-shaped guide sheet; 28. an arc-shaped connecting part; 29. a guide wheel; 3. a limiting plate; 4. a spacing adjustment assembly; 41. an adjusting block; 42. an adjusting lever; 43. a guide rail; 44. a translation slide; 45. connecting blocks; 46. a spacing adjustment link; 5. a material detection assembly; 51. a support plate; 52. a signal acquisition board; 53. a groove-type photoelectric sensor; 54. an induction sheet; 6. a height adjustment assembly; 61. positioning a plate; 62. a guide rail unit; 63. a lifting rod; 64. an adjustment plate; 65. a slider; 66. a fixed block; 67. a height adjustment link; 7. a material poking component; 71. a slide rail; 72. a slide plate; 73. belt transmission; 74. a rotating cylinder; 75. a material stirring frame; 76. a material poking rod; 8. the material blocking component; 81. a material blocking frame; 82. a stopper; 83. a sensor; 9. a wired junction box; 91. a box body; 92. and (4) conducting wires.

Detailed Description

The utility model is described in further detail below with reference to the figures and the embodiments.

Fig. 1-11 show a full-automatic feeding machine for a solar panel wired junction box according to the present invention, which comprises a frame 1, a drum-type bin 2 with two ends rotatably disposed on the frame 1 and a discharge end penetrating through the frame 1, two limiting plates 3 vertically disposed in the drum-type bin 2 and a discharge end penetrating through the frame 1, an interval adjusting assembly 4 disposed on the frame 1 for adjusting an interval between the two limiting plates 3, a material detecting assembly 5 disposed in the frame 1 for detecting the number and positions of wired junction boxes 9 in the two limiting plates 3, a height adjusting assembly 6 disposed on the frame 1 for adjusting the height of the material detecting assembly 5, a material shifting assembly 7 disposed on one side of the frame 1 for driving the wired junction boxes 9 in the drum-type bin 2 to move toward the discharge end, and a material stopping assembly 8 disposed at the discharge end of the two limiting plates 3; the drum-type storage bin 2 is provided with a wire guide groove 21 arranged along the length direction of the drum-type storage bin 2.

During feeding: the staff rotates drum-type feed bin 2 according to wire 92 position of wired terminal box 9 earlier, adjusts the position of metallic channel 21, again according to box body 91 size of wired terminal box 9 through the interval of interval adjusting part 4 adjustment two limiting plates 3, then puts into drum-type feed bin 2 with wired terminal box 9 one by one, wherein box body 91 of wired terminal box 9 arranges in between two limiting plates 3, and wire 92 is located metallic channel 21, realizes spacingly.

When in work: drum-type feed bin 2 removes toward the discharge end through dialling material subassembly 7 drive terminal box, then keeps off material subassembly 8 through the discharge end and carries on spacingly, prevents wired terminal box 9 roll-off drum-type feed bin 2, snatchs wired terminal box 9 through the robot at last and carries out automatic installation work.

Further, the spacing adjusting components 4 are respectively arranged on spacing adjusting execution units at two ends of the rack 1, adjusting rods 42 rotatably arranged on the rack 1 and placed along the length direction of the rack 1, and two sets of spacing adjusting connecting rod units respectively arranged on the adjusting rods 42 and respectively used for driving the spacing adjusting execution units;

each group of the distance adjusting execution units comprises a guide rail 43 horizontally arranged at the end part of the frame 1 and two translation sliding seats 44 which are arranged on the guide rail 43 in a sliding manner and are respectively positioned at two sides of the adjusting rod 42;

each group of the distance adjusting connecting rod units comprises a connecting block 45 arranged on the adjusting rod 42 and two distance adjusting connecting rods 46 with two ends respectively hinged with the connecting block 45 and the translation sliding base 44;

one end of the adjusting rod 42, which is positioned at the feeding end, is provided with an adjusting block 41 which is fixed with the frame 1 through a bolt;

the two limiting plates 3 are respectively arranged on the translation sliding seat 44.

When the distance needs to be adjusted: firstly loosening the bolt on the adjusting block 41, then rotating the adjusting block 41, sequentially driving the adjusting rod 42 and the connecting block 45 to rotate, driving the two translation sliding seats 44 to simultaneously approach or depart from along the guide rail 43 through the two spacing adjusting connecting rods 46, and finally screwing the bolt to fix the adjusting block 41 to realize width adjustment.

Further, the height adjusting assembly 6 comprises guide rail units 62 vertically arranged at two ends of the rack 1, lifting rods 63 arranged below the adjusting rods 42 and having two ends connected with the guide rail units 62, adjusting plates 64 arranged above the adjusting rods 42 and disposed parallel to the adjusting rods 42, and two sets of height adjusting link rod units arranged on the adjusting plates 64 and used for driving the material detecting assembly 5 to lift;

each group of height adjusting connecting rod units comprises a sliding block 65 arranged on the adjusting rod 42 in a sliding mode, a fixed block 66 fixedly arranged on the lifting rod 63, and a height adjusting connecting rod 67, wherein two ends of the height adjusting connecting rod 67 are hinged with the sliding block 65 and the fixed block 66 respectively;

the adjusting plate 64 is respectively connected with the sliding blocks 65 of the two groups of height adjusting connecting rod units, and a positioning plate 61 fixed with the frame 1 through bolts is arranged at one end of the feeding position.

Due to the fact that the wired junction box 9 is large or small, when the wired junction box 9 is small in size, the height of the material detection assembly 5 needs to be adjusted downwards, and when the wired junction box 9 is large in size, the height of the material detection assembly 5 needs to be adjusted upwards; the specific height adjustment is as follows: firstly loosening the bolt on the positioning plate 61, then pushing the adjusting plate 64 along the axis direction of the adjusting rod 42, and because the adjusting plate 64 is hinged with the lifting rod 63 through the height adjusting connecting rod unit, the adjusting plate 64 can drive the lifting rod 63 to drive the material detection assembly 5 to move up and down when moving horizontally, and finally, the positioning plate 61 is fixed by screwing the bolt, so that the height adjustment is realized.

Further, the material detection assembly 5 comprises a support plate 51 arranged below the lifting rod 63 and connected with the fixing blocks 66 in the two groups of height adjusting connecting rod units, a plurality of signal acquisition plates 52 arranged at the bottom of the support plate 51 and placed along the length direction of the support plate 51, and a plurality of groups of detection units arranged at the bottom of the signal acquisition plates 52 and placed along the length direction of the support plate 51; each group of detection units comprises a groove-shaped photoelectric sensor 53 arranged on the signal acquisition board 52 and a sensing piece 54 which is rotatably arranged on the supporting board 51 and the top of which is positioned in a groove of the groove-shaped photoelectric sensor 53.

When in work: the response piece 54 is vertical state under the effect of dead weight, and its top is located cell type photoelectric sensor 53 recess, has placed line terminal box 9 back in drum-type feed bin 2, and line terminal box 9 can make response piece 54 rotate towards one side, makes the top break away from cell type photoelectric sensor 53 recess to can detect out the quantity and the position of wired terminal box 9 in the drum-type feed bin 2, this kind of detection structure not only detects accurately, and longe-lived.

Further, the material poking assembly 7 comprises a sliding rail 71 arranged on one side of the rack 1 and placed along the length direction of the rack 1, a sliding plate 72 arranged on the sliding rail 71 in a sliding manner, a belt transmission 73 arranged on one side of the rack 1 and used for driving the sliding plate 72, a rotary cylinder 74 arranged on the sliding plate 72 and located on one side of the drum-type storage bin 2, a material poking frame 75 arranged at the driving end of the rotary cylinder 74, and two material poking rods 76 arranged on the material poking frame 75 and extending into the drum-type storage bin 2.

During manual feeding: the rotary cylinder 74 drives the material stirring frame 75 to drive the two material stirring rods 76 to be placed in parallel with the material guide rods 26, and at the moment, the wired material stirring rods 76 are located on one side of the drum-type storage bin 2, so that the workers can conveniently feed materials.

When in work: the material stirring frame 75 is driven by the rotary cylinder 74 to drive the two material stirring rods 76 to be vertically placed with the material guide rod 26, so that the two material stirring rods 76 extend into the roller type bin 2 and are positioned on the upper side and the lower side of the material guide rod 26, the material stirring frame 75 is driven by the belt transmission 73 to drive the two material stirring rods 76, the wired junction box 9 in the roller type bin 2 moves towards the discharge end, and the automatic feeding of the wired junction box 9 is realized.

Further, the material blocking assembly 8 comprises material blocking frames 81 respectively arranged at the discharging ends of the two limiting plates 3, stop blocks 82 respectively arranged at the inner sides of the two material blocking frames 81, and a sensor 83 for detecting whether a junction box exists.

When stopping the material: after the material stirring rod 76 drives the wired terminal box 9 at the outermost side to move to the discharging end, the position is limited through the stop block 82, and meanwhile, whether a terminal box exists or not is judged through the sensor 83, so that the manipulator can conveniently grab.

Further, the drum-type storage bin 2 comprises annular cover plates 22 respectively arranged at two ends of the rack 1, two fixing rods 23 for connecting the two annular cover plates 22, and a positioning block 24 arranged on the annular cover plate 22 and fixed at the end of the wired support through a screw; the annular cover plate 22 is provided with an opening 25 for the wire 92 of the wired junction box 9 to pass through; two annular cover plates 22 are respectively provided with a material guiding rod 26 at two sides of the opening 25 to form a wire guiding groove 21.

When in work: firstly, the bolts on the positioning blocks 24 are loosened, then the annular cover plate 22 is rotated to enable the position of the opening 25 to correspond to the position of the lead 92 of the wired junction box 9, and finally the bolts on the positioning blocks 24 are screwed.

Further, the frame 1 comprises two parallel mounting plates 11 and a connecting column 12 for connecting the two mounting plates 11; circular openings 13 which are oppositely arranged are respectively formed in the two mounting plates 11, and arc-shaped grooves 14 are respectively formed in the outer side surfaces of the two mounting plates 11; the back of each annular cover plate 22 is provided with an arc-shaped guide sheet 27 positioned in the arc-shaped groove 14, and the back of each annular cover plate 22 is also provided with arc-shaped connecting parts 28 at two sides of the opening; the arc-shaped connecting part 28 is positioned in the circular opening 13, and at least one guide wheel 29 protruding out of the inner side surface of the mounting plate 11 is arranged on the arc-shaped connecting part 28.

During installation: install annular apron 22 on mounting panel 11, make arc guide plate 27 be located arc groove 14, arc connecting portion 28 is located circular opening 13, because leading wheel 29 bulges mounting panel 11 medial surface, plays limiting displacement, prevents that annular apron 22 from breaking away from mounting panel 11.

The above is only a specific application example of the present invention, and the protection scope of the present invention is not limited in any way. All the technical solutions formed by equivalent transformation or equivalent replacement fall within the protection scope of the present invention.

Claims

1. The utility model provides a full automatic feeding machine of solar panel area line terminal box which characterized in that: the device comprises a rack, a drum-type bin with two ends rotatably arranged on the rack and a discharge end penetrating through the rack, two limiting plates vertically arranged in the drum-type bin and a discharge end penetrating through the rack, an interval adjusting component arranged on the rack and used for adjusting the interval between the two limiting plates, a material detecting component arranged in the rack and used for detecting the number and the position of a wired junction box in the two limiting plates, a height adjusting component arranged on the rack and used for adjusting the height of the material detecting component, a material stirring component arranged on one side of the rack and used for driving the wired junction box in the drum-type bin to move towards the discharge end, and a material blocking component arranged at the discharge end of the two limiting plates; the drum-type storage bin is provided with a wire guide groove arranged along the length direction of the drum-type storage bin.

2. The full-automatic feeding machine for solar panel wired junction boxes according to claim 1, characterized in that: the distance adjusting components are respectively arranged on distance adjusting execution units at two ends of the rack, adjusting rods which are rotatably arranged on the rack and are placed along the length direction of the rack, and two groups of distance adjusting connecting rod units which are respectively arranged on the adjusting rods and are respectively used for driving the distance adjusting execution units;

3. The full-automatic feeding machine for solar panel wired junction boxes according to claim 2, characterized in that: the height adjusting assembly comprises guide rail units which are vertically arranged at two ends of the rack respectively, lifting rods which are arranged below the adjusting rods and two ends of which are connected with the guide rail units respectively, adjusting plates which are arranged above the adjusting rods and are arranged in parallel with the adjusting rods, and a plurality of groups of height adjusting connecting rod units which are arranged on the adjusting plates and are used for driving the material detecting assembly to lift;

4. The full-automatic feeding machine for solar panel wired junction boxes according to claim 3, characterized in that: the material detection assembly comprises a supporting plate, a plurality of signal acquisition plates and a plurality of detection units, wherein the supporting plate is arranged below the lifting rod and connected with the fixing blocks in the plurality of groups of height adjusting connecting rod units; each group of detection units comprises a groove-shaped photoelectric sensor arranged on the signal acquisition board and an induction sheet which is rotatably arranged on the supporting board and the top of the induction sheet is positioned in a groove of the groove-shaped photoelectric sensor.

5. The full-automatic feeding machine for solar panel wired junction boxes according to any one of claims 1-4, characterized in that: the material poking component comprises a sliding rail, a sliding plate, a belt transmission, a rotary cylinder, a material poking frame and two material poking rods, wherein the sliding rail is arranged on one side of the rack and placed along the length direction of the rack, the sliding plate is arranged on the sliding rail in a sliding mode, the belt transmission is arranged on one side of the rack and used for driving the sliding plate, the rotary cylinder is arranged on the sliding plate and located on one side of the drum-type material bin, the material poking frame is arranged at the driving end of the rotary cylinder, and the material poking rods are arranged on the material poking frame and can stretch into the drum-type material bin.

6. The full-automatic feeding machine for solar panel wired junction boxes according to claim 5, characterized in that: the material blocking assembly comprises material blocking frames respectively arranged at the discharge ends of the two limiting plates, stop blocks respectively arranged at the inner sides of the two material blocking frames and a sensor for detecting whether a junction box exists.

7. The full-automatic feeder for solar panel wired junction boxes according to claim 6, characterized in that: the drum-type storage bin comprises annular cover plates arranged at two ends of a rack respectively, a plurality of fixing rods used for connecting the two annular cover plates, and positioning blocks arranged on the annular cover plates and capable of being fixed at the end parts of the wired supports through screws; the annular cover plate is provided with an opening through which a wire on the wired junction box can conveniently pass; and the two annular cover plates are respectively provided with a material guide rod on two sides of the opening to form a wire guide groove.

8. The full-automatic feeder for solar panel wired junction boxes according to claim 7, characterized in that: the rack comprises two mounting plates which are arranged in parallel and a connecting column for connecting the two mounting plates; circular openings which are oppositely arranged are respectively arranged on the two mounting plates, and arc-shaped grooves are respectively arranged on the outer side surfaces of the two mounting plates; the back surface of each annular cover plate is provided with an arc-shaped guide sheet positioned in the arc-shaped groove, and arc-shaped connecting parts are respectively arranged on the two sides of the opening on the back surface of each annular cover plate; the arc connecting portion are located circular opening, be provided with the leading wheel of a protrusion mounting panel medial surface on the arc connecting portion at least.