Insulation fixing device for live replacement of drop-out fuse

Abstract

The invention relates to an insulation fixing device for live replacement of a drop-out fuse, which belongs to the technical field of power maintenance devices and comprises a clamping mechanism, a linkage mechanism, a driving mechanism and a connecting rod mechanism. The clamping mechanism comprises a fixed cover and a movable cover which are matched with each other, a plane connecting mechanism is arranged on the back side of the fixed cover, a bearing support I and a bearing support II are arranged on the plane connecting mechanism, and a bearing support III and a bearing support IV are arranged on the back side of the movable cover; the linkage mechanism comprises a first movable arm and a second movable arm; the driving mechanism comprises a shell, and a steering engine, a steering engine control module, a battery and a supporting frame are arranged in the shell. The connecting rod mechanism is provided with an installation groove used for installing an insulation operation rod. Through automatic driving and insulation design, safe replacement of the drop-out fuse in an electrified state is realized, and the reliability and maintenance efficiency of a power system are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of electric power maintenance devices, and in particular relates to an insulating fixing device for live replacement of a drop-out type fuse. Background Art

[0002] With the rapid development of electric power technology and the continuous updating of power distribution equipment technology, drop-out fuses are used more and more widely in power distribution, especially in the overload and short-circuit protection of transformers in power systems and the closing and opening operations of rated current. Higher requirements are also put forward for the maintenance technology of drop-out fuses. The failure rate of drop-out fuses is relatively high in the current line operation, and replacing drop-out fuses in the power outage state will increase the power outage time of the line and affect the reliability of power supply. Therefore, replacing drop-out fuses in the live state has become the norm. Drop-out fuses include fuse tubes, fuses and bases, among which the fault handling of fuse tubes accounts for an increasingly large proportion in the emergency repair work of live operations. The traditional fault elimination method of drop-out fuses is only applicable to the fault of fuse breakage. When the base porcelain bottle is cracked, the operator will pull open the drop-out fuse tube, and the base porcelain bottle will be broken and the phase-to-phase short circuit will occur, affecting the personal safety of the operator. At the same time, it will also lead to a decrease in the reliability of power supply to users, causing economic losses to users.

[0003] In the prior art, an insulating protective cover for an isolating switch and a drop-out fuse is disclosed with announcement number CN214392174U, which includes a first side cover and a second side cover, the first side cover and the second side cover are connected by a pin shaft and a buckle structure, and also includes a soft rubber cover and a wire pressing block; however, the device only opens and closes the protective cover by manually operating the buckle structure and lacks additional structural reinforcement measures, which easily leads to instability of the protective cover mechanism during live operation; wire pressing blocks of multiple specifications are mainly suitable for cables with different wire diameters, but have limited adaptability to different models of drop-out fuses. Therefore, the device has obvious deficiencies in terms of automation, structural strength, device flexibility and safety. Summary of the invention

[0004] The technical problem solved by the present invention is to overcome the defects in the prior art and provide an insulating fixing device for live replacement of a drop-out fuse.

[0005] The technical solution adopted by the present invention is as follows:

[0006] The insulating fixing device for live replacement of a drop-type fuse described in the present invention comprises a clamping mechanism, a linkage mechanism, a driving mechanism and a connecting rod mechanism. The clamping mechanism comprises a matching fixed cover and a movable cover. A planar connecting mechanism is provided on the back side of the fixed cover. A plurality of fixing hole positions I are provided on the planar connecting mechanism. The driving mechanism comprises a shell. The shell comprises a back plate. A plurality of fixing hole positions II are provided on the back plate. The fixing hole positions I match with the fixing hole positions II. A bearing support I and a bearing support II are also provided on the planar connecting mechanism. The bearing support I is arranged above the bearing support II. A bearing support III and a bearing support IV are provided on the back side of the movable cover. The bearing support III is arranged above the bearing support IV. The linkage mechanism comprises a first movable arm and a second movable arm. The first movable arm is connected between the bearing support I and the bearing support III, and the second movable arm is connected between the bearing support II and the bearing support IV. The shell also comprises a bottom plate. A plurality of fixing hole positions III are provided on the bottom plate. A plurality of fixing hole positions IV are provided on the top of the connecting rod mechanism. The fixing hole positions III match with the fixing hole positions IV.

[0007] A hinge axis I is provided on one side of the plane connection mechanism on the fixed cover, an operating port is provided on the other side of the fixed cover, and female buckles are symmetrically provided on the upper and lower sides of the operating port; a hinge axis II is provided on one side of the movable cover, and a buckle is symmetrically provided on the other side; the hinge axis I is hinged with the hinge axis II, and the female buckle cooperates with the buckle.

[0008] When the clamping mechanism is closed, the whole is a cylindrical shape with round holes at the upper and lower ends and a hollow interior. An insulating layer is provided at one end of the fixed cover close to the female buckle and one end of the movable cover close to the buckle.

[0009] A plurality of ribs are arranged on the back side of the fixed cover and the movable cover. The ribs are triangular and are arranged below the bearing bracket I and the bearing bracket III and above the bearing bracket II and the bearing bracket IV respectively.

[0010] The bearing bracket I, the bearing bracket II, the bearing bracket III and the bearing bracket IV are all provided with openings, and bearings are arranged in the openings. Both ends of the first movable arm and the second movable arm are connected to the bearings.

[0011] The first movable arm is arranged below the bearing bracket I and the bearing bracket III, and the second movable arm is arranged above the bearing bracket II and the bearing bracket IV.

[0012] The first movable arm and the second movable arm both include a movable arm I and a movable arm II. One end of the movable arm I away from the hole is movably connected to another end of the movable arm II away from the hole.

[0013] A servo, a servo control module, a battery and a support frame for installing the servo are arranged in the shell of the driving mechanism; the servo includes a servo body, fixed plates are arranged on both sides of the servo body, the fixed plates are clamped on the support frame, a rotating end is arranged above the servo body, the rotating end is connected with a rotating shaft, the rotating shaft passes through a transmission hole at the top of the shell and is connected to the bearing on the bearing bracket II, and the transmission hole and the opening on the bearing bracket II correspond in the vertical direction.

[0014] The connecting rod mechanism is provided with a mounting groove, and the mounting groove is used for mounting the insulating operating rod.

[0015] The clamping mechanism also includes an inlet insulation cover arranged above the buckle and an outlet insulation cover arranged below the buckle, the two parts of the inlet insulation cover are respectively connected to the upper outer sides of the fixed cover and the movable cover, the two parts of the outlet insulation cover are respectively connected to the lower outer sides of the fixed cover and the movable cover, and an L-shaped incision is provided on one side of the outlet insulation cover close to the fixed cover and the movable cover; the bottom of the inlet insulation cover and the top of the inlet insulation cover are provided with a fuse tube through hole, and the inlet insulation cover is also provided with an operating ring through hole and an inlet terminal through hole.

[0016] The present invention has the following beneficial effects:

[0017] 1. The fixed seat and movable cover in the clamping mechanism can firmly fix the drop-out fuse to ensure that it will not slip or fall off during live operation, thereby improving the safety and reliability of operation.

[0018] 2. The first movable arm and the second movable arm in the linkage mechanism realize the smooth opening and closing of the clamping mechanism, reduce the manual intervention during the operation, and improve the efficiency and accuracy of the operation; the bearing, the first movable arm and the second movable arm make the movement of the clamping mechanism smoother and more stable, reduce friction and wear, and extend the service life of the device.

[0019] 3. The servo, servo control module and rotating shaft in the driving mechanism make the operation simpler and more convenient. The precise control of the servo ensures the accurate movement of the clamping mechanism and improves the safety and reliability of the operation. The servo control module and battery enable the driving mechanism to operate independently without being restricted by external power supply, which improves the portability and flexibility of the device.

[0020] 4. The connecting rod mechanism enables the operator to remotely control the opening and closing of the clamping mechanism through the insulated operating rod, avoiding the risk of direct contact with live parts and further improving the safety of operation.

[0021] 5. Hinge axis I, hinge axis II, female buckle and snap buckle make the opening and closing of the clamping mechanism more flexible and convenient. The cooperation of the female buckle and the snap buckle ensures the tight closure of the clamping mechanism to prevent loosening or falling off during operation.

[0022] 6. The insulation layer effectively prevents electric shock accidents that may occur during operation and ensures the personal safety of the operator.

[0023] 7. The rib plate enhances the structural strength of the clamping mechanism, preventing deformation or damage during live operation, and improving the durability and reliability of the device.

[0024] 8. The inlet and outlet insulation covers in the clamping mechanism can wrap and clamp the inlet and outlet mechanisms of the drop-out fuse while clamping the porcelain bottle, making the clamping operation more secure and improving the stability of the insulation clamping operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a first schematic diagram of the present invention;

[0026] Figure 2 is a second schematic diagram of the present invention;

[0027] Figure 3 This is the front view of the fixed cover;

[0028] Figure 4 It is the rear view of the fixed hood;

[0029] Figure 5 This is the main view of the movable cover;

[0030] Figure 6 This is the rear view of the movable cover;

[0031] Figure 7 is a first schematic diagram of a driving mechanism;

[0032] Figure 8 is a second schematic diagram of the driving mechanism;

[0033] Fig. 9 This is a schematic diagram of the servo;

[0034] Fig.10 It is a schematic diagram of the linkage mechanism;

[0035] Fig.11 It is a schematic diagram of the connecting rod mechanism;

[0036] Fig.12 A schematic diagram of an embodiment of the present invention;

[0037] Fig.13 Schematic diagram of the clamping mechanism.

[0038] Among them: 1. fixed cover; 2. movable cover; 3. plane connection mechanism; 4. fixing hole position I; 5. shell; 6. back plate; 7. fixing hole position II; 8. bearing bracket I; 9. bearing bracket II; 10. bearing bracket III; 11. bearing bracket IV; 12. first movable arm; 13. second movable arm; 14. bottom plate; 15. fixing hole position III; 16. fixing hole position IV; 17. hinge axis I; 18. operation port; 19. female buckle; 20. hinge axis II; 21. Buckle; 22. Insulation layer; 23. Rib plate; 24. Opening; 25. Bearing; 26. Servo; 27. Servo control module; 28. Battery; 29. ​​Support frame; 30. Servo body; 31. Fixed plate; 32. Rotating shaft; 33. Transmission hole; 34. Movable arm I; 35. Movable arm II; 36. Installation groove; 37. Rotating end; 38. Insulation cover of the incoming line end; 39. Insulation cover of the outgoing line end; 40. Fuse tube through hole; 41. Operating ring through hole; 42. Incoming line terminal through hole. DETAILED DESCRIPTION

[0039] like Figures 1 to 12 As shown, the insulating fixing device for live replacement of the drop-out type fuse of the present invention comprises a clamping mechanism, a linkage mechanism, a driving mechanism and a connecting rod mechanism, the clamping mechanism comprises a matching fixed cover 1 and a movable cover 2, a planar connecting mechanism 3 is provided on the back side of the fixed cover 1, a plurality of fixing holes I 4 are provided on the planar connecting mechanism 3, the driving mechanism comprises a shell 5, the shell 5 comprises a back plate 6, a plurality of fixing holes II 7 are provided on the back plate 6, the fixing holes I 4 match the fixing holes II 7; the planar connecting mechanism 3 is also provided with a bearing bracket I 8 and a bearing bracket II 9, the bearing bracket I 8 is arranged above the bearing bracket II 9, the bearing bracket III 10 and the bearing bracket IV 11 are provided on the back side of the movable cover 2, the bearing bracket III 10 is arranged above the bearing bracket IV 11, the linkage mechanism comprises a first movable arm 12 and a second movable arm 13, the first movable arm 12 is connected between the bearing bracket I 8 and the bearing bracket III 10, and the second movable arm 13 is connected to the bearing bracket II 9 and the bearing bracket IV the housing 5 further comprises a bottom plate 14, the bottom plate 14 is provided with a plurality of fixing holes III 15, the top of the connecting rod mechanism is provided with a plurality of fixing holes IV 16, the fixing holes III 15 and the fixing holes IV 16 cooperate.

[0040] A hinge axis I17 is provided on one side of the plane connection mechanism of the fixed cover 1, and an operating port 18 is provided on the other side of the fixed cover 1, and female buckles 19 are symmetrically provided on the upper and lower sides of the operating port 18; a hinge axis II 20 is provided on one side of the movable cover 2, and a buckle 21 is symmetrically provided on the other side; the hinge axis I19 is hinged with the hinge axis II 20, and the female buckle 19 cooperates with the buckle 21.

[0041] When the clamping mechanism is closed, the whole is a cylindrical shape with round holes at the upper and lower ends and a hollow interior. An insulating layer 22 is provided at one end of the fixed cover 1 close to the female buckle 19 and one end of the movable cover 2 close to the buckle 21.

[0042] A plurality of ribs 23 are provided on the back side of the fixed cover 1 and the movable cover 2. The ribs 23 are triangular and are respectively provided below the bearing bracket I 8 and the bearing bracket III 10 and above the bearing bracket II 9 and the bearing bracket IV 11.

[0043] The bearing bracket I 8, the bearing bracket II 9, the bearing bracket III 10 and the bearing bracket IV 11 are all provided with an opening 24, and a bearing 25 is provided in the opening 24, and both ends of the first movable arm 12 and the second movable arm 13 are connected to the bearing 25.

[0044] The first movable arm 12 is arranged below the bearing support I 8 and the bearing support III 10, and the second movable arm 13 is arranged above the bearing support II 9 and the bearing support IV 11.

[0045] The first movable arm 12 and the second movable arm 13 both include a movable arm I 34 and a movable arm II 35, and one end of the movable arm I 34 away from the hole 24 is movably connected to one end of the movable arm II 35 away from the hole 24.

[0046] A steering gear 26, a steering gear control module 27, a battery 28 and a support frame 29 for installing the steering gear 26 are arranged in the housing 5 of the driving mechanism; the steering gear 26 includes a steering gear body 30, and fixing plates 31 are arranged on both sides of the steering gear body 30, and the fixing plates 31 are clamped on the support frame 29. A rotating end 37 is arranged above the steering gear body 30, and the rotating end 37 is connected to a rotating shaft 32. The rotating shaft 32 passes through a transmission hole 33 at the top of the housing 5 to connect to the bearing 25 on the bearing bracket II 9, and the transmission hole 33 corresponds to the opening 24 on the bearing bracket II 9 in the vertical direction.

[0047] The connecting rod mechanism is provided with a mounting groove 36, and the mounting groove 36 is used for mounting the insulating operating rod.

[0048] The clamping mechanism also includes an incoming line insulation cover 38 arranged above the buckle 21 and an outgoing line insulation cover 39 arranged below the buckle 21. The two parts of the incoming line insulation cover 38 are respectively connected to the upper outer sides of the fixed cover 1 and the movable cover 2, and the two parts of the outgoing line insulation cover 39 are respectively connected to the lower outer sides of the fixed cover 1 and the movable cover 2. An L-shaped incision is provided on one side of the outgoing line insulation cover 39 close to the fixed cover 1 and the movable cover 2; a fuse tube through hole 40 is provided at the bottom of the incoming line insulation cover 38 and the top of the outgoing line insulation cover 39, and an operating ring through hole 41 and an incoming line terminal through hole 42 are also provided on the incoming line insulation cover 38.

[0049] Specifically, when the drop-out fuse needs to be replaced under power, the operator can install one end of the insulating operating rod in the installation slot 36 of the connecting rod mechanism, thereby avoiding the operator's need to climb high or replace the fuse at a close distance.

[0050] Specifically, the servo control module 27 in the driving mechanism controls the start and stop of the servo 26, and the servo 26 starts to drive the rotating end 37 to rotate, and then the rotating end 37 drives the rotating shaft 32 to rotate, and the rotating shaft 32 is driven to move through the transmission hole 33 and the bearing 25, so that the bearing 25 on the bearing bracket II 9 rotates, and then drives the first movable arm 12 and the second movable arm 13 in the linkage mechanism to move.

[0051] Specifically, the action of the first movable arm 12 and the second movable arm 13 in the linkage mechanism drives the movable cover 2 in the clamping mechanism to rotate around the hinge axis I17 and the hinge axis II 20 to realize the opening of the clamping mechanism. When closing the clamping mechanism, the fixed cover 1 and the movable cover 2 are closed, and the female buckle 19 and the buckle 21 are matched and locked to ensure that the clamping mechanism is fixed on the outside of the drop-out fuse.

[0052] Specifically, when the clamping mechanism is closed, the fixed cover 1 and the movable cover 2 will form an integral cylindrical structure with circular holes at the upper and lower ends and a hollow interior. An insulating layer 22 is provided at the joint between the end of the fixed cover 1 close to the female buckle 19 and the end of the movable cover 2 close to the buckle, that is, the fixed cover 1 and the movable cover 2, to ensure that the clamping mechanism will not form a circuit during operation to cause electric shock accidents.

[0053] Specifically, a plurality of ribs 23 are provided on the back sides of the fixed cover 1 and the movable cover 2. The ribs 23 are triangular structures, which provide structural support for the bearing bracket I 8, the bearing bracket II 9, the bearing bracket III 10 and the bearing bracket IV 11 connected to the clamping mechanism to prevent deformation or damage in the event of collision.

[0054] Specifically, in the actual live replacement process of the drop-out fuse, firstly, check whether the components of the fixing device are intact to ensure that the connectors are fastened without looseness. After checking, prepare the existing insulating operating rod and install it in the installation slot 36 of the connecting rod mechanism.

[0055] Specifically, the insulating operating lever is operated to control the start and stop of the steering gear 26 in the driving mechanism, thereby controlling the movement of the first movable arm 12 and the second movable arm 13 in the linkage mechanism, and the movable cover 2 opens the clamping mechanism around the hinge axis I17 and the hinge axis II20.

[0056] Specifically, the drop-out fuse is placed at a predetermined position between the fixed cover 1 and the movable cover 2, the insulating operating rod is operated in reverse to close the movable cover 2 and the fixed cover 1, and the female buckle 19 and the buckle 21 are locked together to ensure that the drop-out fuse is firmly clamped.

[0057] Specifically, in the closed state of the clamping mechanism, an insulating tool is used to replace the fuse tube or the fuse of the drop-out fuse. After the replacement is completed, the installation firmness of the fuse is checked again.

[0058] Specifically, Fig.13 As shown, the clamping mechanism performs insulation clamping on the porcelain bottle in the drop-out type fuse during actual operation. Furthermore, by providing the inlet end insulation cover 38 and the outlet end insulation cover 39, the inlet end mechanism and the outlet end mechanism of the drop-out type fuse can be insulated and clamped while the porcelain bottle is insulated; the inlet end insulation cover 38 is provided with an operating ring through hole 41 and an inlet terminal through hole 42. When clamped closed, the operating ring in the drop-out type fuse passes through the operating ring through hole 41, and the vertical part of the L-shaped inlet terminal passes through the inlet terminal through hole 42; the outlet end insulation cover 39 is provided with an L-shaped cutout to prevent the components in the outlet end mechanism from blocking the outlet end insulation cover 39 during the clamping operation; the bottom of the inlet end insulation cover 38 and the top of the outlet end insulation cover 39 are provided with fuse tube through holes 40 corresponding to each other in the vertical direction. When the clamping operation is performed, the fuse tube in the drop-out type fuse passes through the fuse tube through hole 40.

[0059] The above description is only for illustrating the basic principle, main features and technical advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above-mentioned embodiments. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. An insulation fixing device for live replacement of a drop-out fuse, comprising a clamping mechanism, a linkage mechanism, a driving mechanism and a connecting rod mechanism, characterized in that: The clamping mechanism comprises a fixed cover (1) and a movable cover (2) which match each other. A plane connection mechanism (3) is provided on the back side of the fixed cover (1). A plurality of fixing holes I (4) are provided on the plane connection mechanism (3). The driving mechanism comprises a housing (5). The housing (5) comprises a back plate (6). A plurality of fixing holes II (7) are provided on the back plate (6). The fixing holes I (4) match with the fixing holes II (7). The plane connection mechanism (3) is also provided with a bearing support I (8) and a bearing support II (9). The bearing support I (8) is provided above the bearing support II (9). The movable cover (2) is provided with a bearing support III (10) and a shaft support II (11) on the back side. The bearing bracket IV (11), the bearing bracket III (10) is arranged above the bearing bracket IV (11), the linkage mechanism includes a first movable arm (12) and a second movable arm (13), the first movable arm (12) is connected between the bearing bracket I (8) and the bearing bracket III (10), and the second movable arm (13) is connected between the bearing bracket II (9) and the bearing bracket IV (11); the shell (5) also includes a bottom plate (14), the bottom plate (14) is provided with a plurality of fixing holes III (15), and the top of the connecting rod mechanism is provided with a plurality of fixing holes IV (16), and the fixing holes III (15) are matched with the fixing holes IV (16).

2. The insulating fixing device for live replacement of a drop-out type fuse according to claim 1, characterized in that: A hinge axis I (17) is provided on one side of the upper plane connection mechanism (3) of the fixed cover (1), and an operating port (18) is provided on the other side of the fixed cover (1), and female buckles (19) are symmetrically provided on the upper and lower sides of the operating port (18); a hinge axis II (20) is provided on one side of the movable cover (2), and a buckle (21) is symmetrically provided on the other side; the hinge axis I (17) is hingedly connected to the hinge axis II (20), and the female buckle (19) and the buckle (21) are matched.

3. The insulating fixing device for live replacement of a drop-out fuse according to claim 2, characterized in that: When the clamping mechanism is closed, the clamping mechanism is in the shape of a cylinder with circular holes at both ends and a hollow interior. An end of the fixed cover (1) close to the female buckle (19) and an end of the movable cover (2) close to the buckle (21) are provided with an insulating layer (22).

4. The insulating fixing device for live replacement of a drop-out type fuse according to claim 1, characterized in that: A plurality of ribs (23) are provided on the back side of the fixed cover (1) and the movable cover (2), wherein the ribs (23) are triangular in shape and are respectively provided below the bearing support I (8) and the bearing support III (10) and above the bearing support II (9) and the bearing support IV (11).

5. The insulating fixing device for live replacement of a drop-out type fuse according to claim 1, characterized in that: The bearing bracket I (8), the bearing bracket II (9), the bearing bracket III (10) and the bearing bracket IV (11) are all provided with openings (24), and bearings (25) are provided in the openings (24), and both ends of the first movable arm (12) and the second movable arm (13) are connected to the bearings (25).

6. The insulating fixing device for live replacement of a drop-out fuse according to claim 1, characterized in that: The first movable arm (12) is arranged below the bearing support I (8) and the bearing support III (10), and the second movable arm (13) is arranged above the bearing support II (9) and the bearing support IV (11).

7. The insulating fixing device for live replacement of a drop-out type fuse according to claim 1, characterized in that: The first movable arm (12) and the second movable arm (13) both comprise a movable arm I (34) and a movable arm II (35), and one end of the movable arm I (34) away from the hole (24) is movably connected to one end of the movable arm II (35) away from the hole (24).

8. The insulating fixing device for live replacement of a drop-out type fuse according to claim 1, characterized in that: A steering gear (26), a steering gear control module (27), a battery (28) and a support frame (29) for installing the steering gear (26) are arranged in the housing (5) of the driving mechanism; the steering gear (26) comprises a steering gear body (30), fixing plates (31) are arranged on both sides of the steering gear body (30), the fixing plates (31) are clamped on the support frame (29), a rotating end (37) is arranged above the steering gear body (30), the rotating end (37) is connected to a rotating shaft (32), the rotating shaft (32) passes through a transmission hole (33) at the top of the housing (5) and is connected to a bearing (25) on a bearing bracket II (9), the transmission hole (33) and an opening (24) on the bearing bracket II (9) correspond in position in the vertical direction.

9. The insulating fixing device for live replacement of a drop-out type fuse according to claim 1, characterized in that: The connecting rod mechanism is provided with a mounting groove (36), and the mounting groove (36) is used for mounting the insulating operating rod.

10. The insulating fixing device for live replacement of a drop-out fuse according to claim 1, characterized in that: The clamping mechanism further comprises an inlet insulation cover (38) arranged above the buckle (21) and an outlet insulation cover (39) arranged below the buckle (21); the two parts of the inlet insulation cover (38) are respectively connected to the upper outer sides of the fixed cover (1) and the movable cover (2); the two parts of the outlet insulation cover (39) are respectively connected to the lower outer sides of the fixed cover (1) and the movable cover (2); an L-shaped cutout is provided on one side of the outlet insulation cover (39) close to the fixed cover (1) and the movable cover (2); a fuse tube through hole (40) is provided at the bottom of the inlet insulation cover (38) and the top of the inlet insulation cover (38); and an operating ring through hole (41) and an inlet terminal through hole (42) are also provided on the inlet insulation cover (38).

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