A dispatching and control device based on a distributed power distribution network

Abstract

The utility model discloses a kind of based on distributed power distribution network dispatching management and control device, belong to power distribution equipment technical field, this based on distributed power distribution network dispatching management and control device, including management and control cabinet, first circuit breaker, second circuit breaker, first contact, second contact, main circuit contact, backplate, insulating seat, sealing cover, dispatching component, the dispatching component is used to alternately make the first contact, the second contact with the main circuit contact electrically connected.The utility model in, by dispatching component makes main circuit contact and first contact, second contact alternately contact, realize electric connection, to realize the dispatching management and control of circuit, without manual operation processing, and because first contact, second contact and main circuit contact contact are completed in insulating seat, and insulating seat is vacuumized, in vacuum environment, arc generated by circuit conduction, disconnecting will not continue, to reduce the security risk generated by arc.

Description

TECHNICAL FIELD

[0001] The utility model belongs to power distribution equipment technical field, specifically related to a kind of based on distributed power distribution network dispatching control device. BACKGROUND

[0002] When distributed power is in grid control, different circuits need to be connected to realize scheduling. According to the search of Chinese utility model patent publication number CN213937436U, a kind of active distribution network voltage control system based on distributed power supply is disclosed. In the technical solution, the electrically conductive column is contacted with the electrically conductive sleeve by moving up and down corresponding to the motor-driven sliding plate, and the circuit is turned on. This technical solution solves the safety hazards caused by the current manpower to allocate power grid, but since the circuit is connected instantaneously, an arc will be generated. The existing technology cannot avoid the arc, so there is still a certain safety hazard. UTILITY MODEL CONTENTS

[0003] The technical problem to be solved by the utility model is to overcome the shortcomings of the above-mentioned prior art, and to provide a kind of based on distributed power distribution network dispatching control device.

[0004] The technical solution adopted to solve the above technical problems is: a kind of based on distributed power distribution network dispatching control device, including control cabinet, first circuit breaker and second circuit breaker are installed in the control cabinet, the incoming line end of the first circuit breaker and the second circuit breaker is connected with first contact and second contact in turn respectively, main circuit contact is also installed in the control cabinet, and further comprising:

[0005] The backboard is fixed in the control cabinet, the backboard is located above the main circuit contact and below the first contact and the second contact;

[0006] The insulating seat is connected to the surface of the backboard, the insulating seat is hollow inside and one side is open, the insulating seat is installed with sealing cover plate on the open side, the top surface of the insulating seat is provided with first perforation for the first contact and the second contact to pass freely, and the bottom surface of the insulating seat is provided with second perforation for the main circuit contact to pass freely;

[0007] The dispatching assembly is arranged in the insulating seat, and the dispatching assembly is used to alternately electrically connect the first contact, the second contact and the main circuit contact.

[0008] By the above technical scheme, the main circuit contact piece and the first contact piece and the second contact piece are alternately contacted by the dispatching assembly to realize electrical connection, thereby realizing dispatching control of the circuit without manual operation and processing, and since the contact of the first contact piece and the second contact piece with the main circuit contact piece is completed in the insulating seat which is vacuumized, the electric arc generated by circuit conduction and disconnection cannot be sustained in the vacuum environment, thereby reducing the safety hazard caused by the electric arc.

[0009] Further, the insulating seat side wall is provided with a vacuumizing port, and a manual valve is mounted on the vacuumizing port.

[0010] By the above technical scheme, the inside of the insulating seat is vacuumized by the external vacuumizing equipment through the vacuumizing port, thereby making the inside cavity of the insulating seat in a vacuum state, and after the manual valve is closed, the vacuum state of the inside cavity of the insulating seat can be sustained.

[0011] Further, the dispatching assembly comprises an insulating sliding block slidingly connected to the inside cavity of the insulating seat, a through contact piece is arranged on the top surface of the insulating sliding block, one end of the through contact piece is electrically connected to the main circuit contact piece through a cable, a driving shaft is detachably connected to the surface of the insulating sliding block, one end of the driving shaft passes through the sealing cover plate and is freely slidable, and a driving unit for driving the driving shaft to move along the sliding direction of the insulating sliding block in the inside cavity of the insulating seat is arranged on the surface of the sealing cover plate.

[0012] By the above technical scheme, the insulating sliding block is driven to move by the driving unit, thereby making the through contact piece alternately contact the first contact piece and the second contact piece, and making the first circuit breaker and the second circuit breaker conduct the circuit corresponding to the main circuit contact piece, thereby realizing dispatching control of the power grid.

[0013] Further, protrusions are fixedly connected to the outer walls on both sides of the insulating sliding block, and sliding grooves for clamping the protrusions are arranged on the cavity wall of the insulating seat, and the protrusions are freely slidable in the sliding grooves.

[0014] By the above technical scheme, the protrusions slide in the sliding grooves, and the sliding grooves limit the protrusions, thereby making the insulating sliding block slidingly connected in the inside cavity of the insulating seat.

[0015] Further, the driving unit comprises a cylinder mounting seat connected to the surface of the sealing cover plate, a cylinder is mounted on the cylinder mounting seat, a movable seat is drivingly connected to the cylinder rod of the cylinder, the movable seat is slidingly and contactingly connected to the surface of the sealing cover plate, an emptying groove for freely passing the driving shaft is arranged on the surface of the movable seat, a sliding pin is fixedly connected to one end of the driving shaft passing through the sealing cover plate, a waist-shaped hole for freely passing the sliding pin is arranged on the surface of the movable seat, and the length direction of the waist-shaped hole has an included angle with the axial direction of the driving shaft.

[0016] By the technical scheme, the movable seat slides on the surface of the sealing cover plate by the extension and retraction of the cylinder rod of the cylinder, and the sliding pin slides in the waist-shaped hole during the sliding, and the length direction of the waist-shaped hole is at an angle with the axial direction of the driving shaft, so that the driving shaft moves along the axial direction thereof during the sliding of the sliding pin in the waist-shaped hole, and the driving shaft drives the insulating sliding block to slide in the inner cavity of the insulating seat, and the structure is simple and the cost is low.

[0017] Further, the driving shaft penetrates the insulating sliding block and is fixedly sleeved with two stop washers at one end penetrating the inner cavity of the insulating seat, and the two stop washers respectively abut against the outer walls of the insulating sliding block in the thickness direction.

[0018] By the technical scheme, the two stop washers abut against the outer walls of the insulating sliding block, so as to detachably connect the driving shaft and the insulating sliding block together, and the driving shaft can synchronously drive the insulating sliding block to slide in the inner cavity of the insulating seat when moving along the axial direction thereof.

[0019] Further, the hole walls of the first perforation and the second perforation are provided with rubber layers, and the rubber layers are correspondingly in contact connection with the first contact piece, the second contact piece and the main circuit contact piece.

[0020] By the technical scheme, the rubber layers are in contact with the first contact piece, the second contact piece and the main circuit contact piece, so that the sealing effect of the first perforation and the surfaces of the first contact piece and the second contact piece is good, and the sealing effect of the second perforation and the surface of the main circuit contact piece is also good.

[0021] Further, the inner cavity of the insulating seat is provided with a straightening block made of insulating material, a straightening opening is formed in the surface of the straightening block and is used for allowing the contact piece to freely pass through, and the inner cavity of the insulating seat is provided with a straightening unit used for driving the straightening block to slide on the surface of the contact piece when the insulating sliding block moves.

[0022] By the technical scheme, the straightening block is driven by the straightening unit to slide on the surface of the contact piece when the insulating sliding block slides in the inner cavity of the insulating seat, and the straightening opening straightens the contact piece which does not contact the first contact piece and the second contact piece at this time, so as to avoid the deformation of the contact piece due to the compressive stress caused by the long-term contact of the contact piece with the first contact piece and the second contact piece.

[0023] Further, the straightening unit comprises a short pin fixed to the outer walls of the straightening block in the length direction, an arc-shaped sliding groove is formed in the inner cavity wall of the insulating seat and is used for inserting the short pin, and the arc-shaped raised part of the arc-shaped sliding groove faces the first contact piece and the second contact piece.

[0024] By the technical scheme, when the insulating sliding block slides in the inner cavity of the insulating base, the short pin will slide in the arc-shaped sliding groove, when the short pin slides from the end point of the arc-shaped sliding groove to the arc-shaped raised position, the straightening block will slide on the surface of the contact patch along the length direction of the contact patch, and the straightening opening can straighten the contact patch when sliding.

[0025] Further, the diameter size of the arc-shaped sliding groove is smaller than the interval size of the first contact patch and the second contact patch.

[0026] By the technical scheme, when the straightening block slides in the arc-shaped sliding groove from one end point to another end point, the straightening block will not contact the first contact patch and the second contact patch.

[0027] The utility model discloses the beneficial effects are as follows:

[0028] In the utility model, the first contact patch and the second contact patch are alternately contacted with the main circuit contact patch by the dispatching assembly, the electrical connection is realized, the dispatching control of the circuit is realized, manual operation processing is not needed, and because the contact between the first contact patch, the second contact patch and the main circuit contact patch is completed in the insulating base, the insulating base is vacuumized, the electric arc generated by the circuit conduction and disconnection does not last in the vacuum environment, and the safety hidden danger generated by the electric arc is reduced.

[0029] In the utility model, the driving shaft is driven to slide in the inner cavity of the insulating base by the extension and retraction of the cylinder rod of the cylinder, the sliding pin will slide in the waist-shaped hole when sliding, because the length direction of the waist-shaped hole is at an angle with the axial direction of the driving shaft, the driving shaft can be driven to move along the axial direction of itself when the sliding pin slides in the waist-shaped hole, and the insulating sliding block is driven to slide in the inner cavity of the insulating base, so that the structure is simple and the cost is low.

[0030] In the utility model, when the insulating sliding block slides in the inner cavity of the insulating base, the short pin will slide in the arc-shaped sliding groove, when the short pin slides from the end point of the arc-shaped sliding groove to the arc-shaped raised position, the straightening block will slide on the surface of the contact patch along the length direction of the contact patch, and the straightening opening can straighten the contact patch when sliding, so that the contact patch can be forced to straighten when being bent and deformed, and the use is not affected. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 It is the overall structure schematic diagram of the dispatching control device of the distributed power distribution network based on the utility model;

[0032] Figure 2 It is Figure 1 The position relation schematic diagram of another perspective in the utility model;

[0033] Figure 3Is the position relation schematic view of the utility model after omitting the control cabinet;

[0034] Figure 4 Is Figure 3 The position relation schematic view of another perspective in the utility model;

[0035] Figure 5 Is Figure 3 The position relation schematic view of the utility model after omitting the sealing cover plate;

[0036] Figure 6 Is Figure 5 The enlarged schematic view of the local structure of A in the utility model;

[0037] Figure 7 Is Figure 5 The position relation schematic view of the utility model after omitting the insulation seat;

[0038] Figure 8 The structure schematic view of the insulation seat in the utility model;

[0039] Figure 9 The structure schematic view of the straightening block in the utility model.

[0040] Reference signs: 1, main circuit contact; 2, control cabinet; 3, air cylinder; 4, first contact; 5, first circuit breaker; 6, second circuit breaker; 7, second contact; 8, insulation seat; 9, back plate; 10, sealing cover plate; 11, movable seat; 12, vacuumizing port; 13, insulation sliding block; 14, cable; 15, straightening block; 16, stop washer; 17, driving shaft; 18, sliding pin; 19, waist-shaped hole; 20, emptying groove; 21, on contact; 22, arc-shaped sliding groove; 23, sliding groove; 24, manual valve; 25, straightening port; 26, short pin. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical scheme and advantages of the utility model more clearly, the following is combined with the drawings and examples, and the utility model is further described in detail.It should be understood that the specific examples described here are only used to explain the utility model, and are not used to limit the utility model.

[0042] As Figures 1-9As shown, the embodiment provides a kind of based on distributed power distribution network scheduling control device, including the control cabinet 2 of one side open and hinged with cabinet door (not shown in drawing), first circuit breaker 5 and second circuit breaker 6 are installed in control cabinet 2, the incoming line end of first circuit breaker 5 and second circuit breaker 6 is connected with first contact 4 and second contact 7 in turn respectively, the outgoing line end of first circuit breaker 5, second circuit breaker 6 is electrically connected with two branch circuits, in addition, main circuit contact 1 is also installed in control cabinet 2, main circuit contact 1 is electrically connected with main circuit, backplate 9 is installed in control cabinet 2, in addition, backplate 9 is located between main circuit contact 1, first contact 4 (second contact 7), that is, backplate 9 is located above main circuit contact 1, and below first contact 4, second contact 7, hollow insulating seat 8 is installed on the surface of backplate 9 by screw mode, insulating seat 8 is open to the cabinet door side of control cabinet 2, sealing cover plate 10 is installed on the open side of insulating seat 8, after sealing cover plate 10 is installed on insulating seat 8 using screw, sealing cover plate 10 can seal the mouth of insulating seat 8, so that the inner cavity of insulating seat 8 is isolated from the air outside, in addition, the top surface of insulating seat 8 is provided with first perforation for first contact 4 and second contact 7 to pass freely, the bottom surface of insulating seat 8 is provided with second perforation for main circuit contact 1 to pass freely, the hole wall of first perforation and second perforation is provided with rubber layer (not shown in drawing), rubber layer is correspondingly connected with first contact 4, second contact 7, main circuit contact 1, so that when rubber layer is in contact with first contact 4, second contact 7, main circuit contact 1, the sealing effect of first perforation and the surface of first contact 4, second contact 7 is good, and also make the sealing of second perforation and the surface of main circuit contact 1 is good, the side wall of insulating seat 8 is provided with vacuumizing port 12, manual valve 24 is installed on vacuumizing port 12, external vacuumizing equipment is vacuumized inside insulating seat 8 through vacuumizing port 12, so that the inner cavity of insulating seat 8 is in vacuum state, and after closing manual valve 24, the vacuum state of the inner cavity of insulating seat 8 can be sustained.

[0043] The insulating slider 13 in the inner cavity of the insulating seat 8, specifically, the outer wall of the two sides of the insulating slider 13 is fixedly connected with a protrusion, and the inner cavity wall of the insulating seat 8 is provided with a sliding groove 23 for clamping the protrusion, and the protrusion is freely slid in the sliding groove 23. The protrusion is slid in the sliding groove 23, so that the insulating slider 13 is slidably connected in the inner cavity of the insulating seat 8. The top surface of the insulating slider 13 is provided with a connecting contact 21. One end of the connecting contact 21 is electrically connected with the main circuit contact 1 through a cable 14. The surface of the insulating slider 13 is provided with a driving shaft 17, and the driving shaft 17 is freely slid on the insulating slider 13. The end of the driving shaft 17 penetrating into the inner cavity of the insulating seat 8 is fixedly sleeved with two stop washers 16. The two stop washers 16 are respectively abutted with the outer walls of the two sides of the insulating slider 13 in the thickness direction. The two stop washers 16 generate an abutting force on the outer wall of the insulating slider 13, so as to detachably connect the driving shaft 17 and the insulating slider 13 together. When the driving shaft 17 moves along its own axial direction, the driving shaft 17 can synchronously drive the insulating slider 13 to slide in the inner cavity of the insulating seat 8. The end of the driving shaft 17 penetrating out of the sealing cover plate 10 is freely slid;

[0044] The surface of the sealing cover plate 10 is screw-connected with a cylinder mounting seat. The cylinder mounting seat is installed with a cylinder 3. The cylinder rod of the cylinder 3 is drivingly connected with a movable seat 11. The movable seat 11 is slidably connected to the surface of the sealing cover plate 10. The surface of the movable seat 11 is provided with a clearance groove 20 for freely passing the driving shaft 17. The end of the driving shaft 17 penetrating out of the sealing cover plate 10 is fixedly connected with a sliding pin 18. The surface of the movable seat 11 is provided with a waist-shaped hole 19 for freely passing the sliding pin 18. The length direction of the waist-shaped hole 19 and the axial direction of the driving shaft 17 have an included angle. The cylinder rod of the cylinder 3 is telescopic, so as to make the movable seat 11 slide on the surface of the sealing cover plate 10. When sliding, the sliding pin 18 slides in the waist-shaped hole 19. Since the length direction of the waist-shaped hole 19 and the axial direction of the driving shaft 17 have an included angle, the sliding pin 18 can make the driving shaft 17 move along its own axial direction during the sliding process in the waist-shaped hole 19. Thus, the driving shaft 17 drives the insulating slider 13 to slide in the inner cavity of the insulating seat 8.

[0045] The inner cavity of the insulating seat 8 is provided with a straightening block 15 made of insulating material. The surface of the straightening block 15 is provided with a straightening opening 25 for freely passing the connecting contact 21. The length direction of the two sides of the straightening block 15 is fixedly connected with a short pin 26. The inner cavity wall of the insulating seat 8 is provided with an arc-shaped sliding groove 22 for inserting the short pin 26. The arc-shaped protruding part of the arc-shaped sliding groove 22 faces the first contact 4 and the second contact 7. The diameter size of the arc-shaped sliding groove 22 is smaller than the interval size of the first contact 4 and the second contact 7.

[0046] Reference Figure 5 And Figure 7, the number of the first contact pieces 4 and the second contact pieces 7 is four, the first contact pieces 4 and the second contact pieces 7 are in one-to-one correspondence, the first contact pieces 4 and the second contact pieces 7 are respectively located on opposite sides of the sliding direction of the insulating slider 13 in the inner cavity of the insulating seat 8, specifically, the first contact pieces 4 are arranged on one side of the insulating seat 8 adjacent to the back plate 9, the second contact pieces 7 are arranged on one side of the insulating seat 8 adjacent to the sealing cover plate 10, and the connecting contact piece 21 is located between the first contact pieces 4 and the second contact pieces 7. When the insulating slider 13 slides in the inner cavity of the insulating seat 8 along the surface perpendicular to the thickness direction of the back plate 9 (or the sealing cover plate 10), the connecting contact piece 21 will move between the first contact pieces 4 and the second contact pieces 7. Referring to Figure 5 , when the insulating slider 13 moves towards the sealing cover plate 10, the connecting contact piece 21 will be in contact with the second contact piece 7, and when the insulating slider 13 moves towards the back plate 9, the connecting contact piece 21 will be in contact with the first contact piece 7.

[0047] The working principle of the embodiment is as follows:

[0048] When the power grid is scheduled, the management personnel remotely connects the circuit for controlling the electromagnetic valve for controlling the action of the air cylinder 3, so that the air cylinder rod of the air cylinder 3 is elongated or shortened, thereby driving the movable seat 11 to slide on the surface of the sealing cover plate 10. When sliding, the sliding pin 18 will slide in the waist-shaped hole 19. Since the length direction of the waist-shaped hole 19 is at an angle with the axial direction of the driving shaft 17, the sliding pin 18 can make the driving shaft 17 move along its own axial direction during the sliding process in the waist-shaped hole 19, thereby driving the insulating slider 13 to slide in the inner cavity of the insulating seat 8. The connecting contact piece 21 changes from the state of being in contact with the first contact piece 4 to the state of being in contact with the second contact piece 7, or from the state of being in contact with the second contact piece 7 to the state of being in contact with the first contact piece 4, thereby realizing the grid connection of the main circuit and the branch circuit, realizing the scheduling and control of the power grid. In addition, since the contact between the first contact piece 4 and the second contact piece 7 and the main circuit contact piece 1 is completed in the insulating seat 8, the insulating seat 8 is vacuumized, and in the vacuum environment, the electric arc generated by the on-off of the circuit will not last, thereby reducing the safety hazard caused by the electric arc;

[0049] In addition, when the insulating slider 13 slides in the insulating seat 8, the short pin 26 slides in the arc-shaped sliding groove 22. When the short pin 26 slides from the end point of the arc-shaped sliding groove 22 to the arc-shaped raised position, the straightening block 15 will slide on the surface of the connecting contact piece 21 along the length direction of the connecting contact piece 21. When sliding, the straightening opening 25 can straighten the connecting contact piece 21, and then as the insulating slider 13 continues to move, the short pin 26 will slide from the arc-shaped raised position to the other end point of the arc-shaped sliding groove 22, so that the straightening block 15 will slide reversely on the surface of the connecting contact piece 21 to the initial position, thereby avoiding contact with the first contact piece 4 and the second contact piece 7.

[0050] The above is only a preferred embodiment of the present application, and is not intended to limit the scope of protection of the present application.

Claims

1. A distributed power distribution network scheduling and control device, comprising a control cabinet (2), a first circuit breaker (5) and a second circuit breaker (6) are installed in the control cabinet (2), the incoming line ends of the first circuit breaker (5) and the second circuit breaker (6) are connected with a first contact (4) and a second contact (7) in sequence respectively, and a main circuit contact (1) is also installed in the control cabinet (2), characterized in that, Also include: Fixed in the pipe control cabinet (2) backplane (9), the backplane (9) is provided above the main circuit contact (1), and is located below the first contact (4), the second contact (7); Connected to the surface of the backplane (9) insulation seat (8), the inside of the insulation seat (8) is hollow and one side is open, the open side of the insulation seat (8) is provided with a sealing cover plate (10), the top surface of the insulation seat (8) is provided with a first through hole for the first contact (4) and the second contact (7) to pass freely, the bottom surface of the insulation seat (8) is provided with a second through hole for the main circuit contact (1) to pass freely; The dispatching component is arranged in the insulation seat (8), the dispatching component is used for alternately connecting the first contact (4), the second contact (7) and the main circuit contact (1), the dispatching component includes an insulation slider (13) slidably connected to the inner cavity of the insulation seat (8), the top surface of the insulation slider (13) is provided with a contact (21), one end of the contact (21) is electrically connected to the main circuit contact (1) through a cable (14), the surface of the insulation slider (13) is detachably connected to a driving shaft (17), one end of the driving shaft (17) penetrates the sealing cover plate (10) and freely slides, the surface of the sealing cover plate (10) is provided with a driving unit for driving the driving shaft (17) to move along the sliding direction of the insulation slider (13) in the inner cavity of the insulation seat (8); The driving unit includes a cylinder mounting seat connected to the surface of the sealing cover plate (10), the cylinder mounting seat is provided with a cylinder (3), the cylinder rod of the cylinder (3) is drivingly connected to a movable seat (11), the movable seat (11) is slidably connected to the surface of the sealing cover plate (10), the surface of the movable seat (11) is provided with a clearance groove (20) for the driving shaft (17) to pass freely, one end of the driving shaft (17) penetrating the sealing cover plate (10) is fixedly connected to a sliding pin (18), the surface of the movable seat (11) is provided with a waist-shaped hole (19) for the sliding pin (18) to pass freely, the length direction of the waist-shaped hole (19) has an included angle with the axial direction of the driving shaft (17). 2.The dispatching and control device based on the distributed power distribution network of claim 1, characterized in that, The side wall of the insulation seat (8) is provided with a vacuumizing port (12), and the vacuumizing port (12) is provided with a manual valve (24). 3.The dispatching and control device based on the distributed power distribution network of claim 1, characterized in that, The two side walls of the insulation slider (13) are fixedly connected with protrusions, and the inner cavity wall of the insulation seat (8) is provided with sliding grooves (23) for clamping the protrusions, and the protrusions freely slide in the sliding grooves (23). 4.The dispatching and control device based on the distributed power distribution network of claim 1, characterized in that, The driving shaft (17) slidably penetrates the insulation slider (13), and one end of the driving shaft (17) penetrating the inner cavity of the insulation seat (8) is fixedly sleeved with two stop washers (16), and the two stop washers (16) respectively abut against the two side walls of the insulation slider (13) in the thickness direction.

5. The distributed power supply distribution network dispatching and control device according to claim 1, characterized in that, The hole wall of the first and second through holes is provided with a rubber layer, which is in contact with the first contact piece (4), the second contact piece (7) and the main circuit contact piece (1) respectively. 6.The dispatching and control device based on the distributed power distribution network of claim 1, characterized in that, The inner cavity of the insulating seat (8) is provided with a straightening block (15) made of insulating material, the surface of the straightening block (15) is provided with a straightening opening (25) for allowing the contact piece (21) to pass freely, and the inner cavity of the insulating seat (8) is provided with a straightening unit for driving the straightening block (15) to slide on the surface of the contact piece (21) when the insulating sliding block (13) moves. 7.The dispatching and control device based on the distributed power distribution network of claim 6, characterized in that, The straightening unit comprises a short pin (26) fixed to the length direction of the two side walls of the straightening block (15), the inner cavity wall of the insulating seat (8) is provided with an arc-shaped sliding groove (22) for inserting the short pin (26), and the arc-shaped protruding part of the arc-shaped sliding groove (22) faces the first contact piece (4) and the second contact piece (7). 8.The dispatching and control device based on the distributed power distribution network of claim 7, characterized in that, The diameter of the arc-shaped sliding groove (22) is smaller than the spacing size of the first contact piece (4) and the second contact piece (7).

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