Wireless stacking energy storage device

Abstract

The utility model discloses a wireless stacking energy storage device, which comprises a plurality of power supply devices arranged from top to bottom, a fixing mechanism is arranged between any two adjacent power supply devices, the fixing mechanism comprises a slot and a plug board which are respectively arranged on the two power supply devices, and an elastic reset piece is arranged between the plug board and the power supply devices. A magnet part is fixed on the insertion plate and is provided with an electromagnet matched for use, and the electromagnet is matched with the elastic reset piece to enable the insertion plate to be telescopically arranged to be inserted into or separated from the insertion groove. According to the utility model, a fixing structure in the prior art is improved, the power-on and power-off of the electromagnet can be realized through the switch button, and the insertion or separation of the insertion plate and the insertion slot can be realized only by pressing the switch button, so that the fixation and unlocking between two adjacent power supply devices are more convenient, and the use is more convenient. An operator does not need to repeatedly rotate a screw rod for locking two adjacent power supply devices or unlocking the two adjacent power supply devices, so that the stacked energy storage device is more convenient to assemble and disassemble.

Description

Technical Field

[0001] The utility model relates to the technical field of energy storage equipment, in particular to a wireless stacking energy storage device. Background Art

[0002] Mobile energy storage equipment has limited power supply capacity under certain size, appearance and weight, and cannot meet customers' power demand for stable outdoor and limited indoor space under specific requirements.

[0003] In order to solve the above problems, the prior art uses a stacking method to combine energy storage devices with power packs, such as the patent application number CN202321715623.8, which is called a stacked modular household energy storage device. In this patent, one or more energy storage devices are stacked on top of the power host, and the adjacent power hosts and energy storage devices or two adjacent energy storage devices are connected in series and parallel through AC plugs and AC sockets, which can meet a large number of power supply needs while eliminating additional series cables and avoiding cable storage.

[0004] In the above patent, in order to ensure the stability of the connection between the two energy storage devices arranged up and down (or the energy storage device and the power supply host arranged up and down), a fixed structure is provided between the two energy storage devices arranged up and down, and the fixed structure includes a satisfying socket and a positioning socket used in conjunction with each other. The satisfying socket and the positioning socket are selectively arranged on the two energy storage devices, and a screw is provided on the positioning socket. The screw is rotated to lock and fix the satisfying socket and the positioning socket.

[0005] In this patent, four fixing structures are set between two adjacent energy storage devices, and the two energy storage devices are fixed by fixing them at four corners to ensure the stability of multiple energy storage devices during use and transportation. However, the use of the fixing structure in the above patent requires the user to repeatedly turn multiple screws to fix the energy storage device, which is extremely inconvenient to operate. If the power supply host stacks multiple energy storage devices, it is particularly inconvenient to replace the energy storage device in the middle. Therefore, it is necessary to provide a stackable energy storage device that is easy to disassemble and assemble. Utility Model Content

[0006] In view of the deficiencies in the prior art, the utility model provides a wireless stacking energy storage device, which solves the problem in the prior art that the fixed structure between multiple stacked energy storage devices makes replacement and use of the energy storage devices inconvenient.

[0007] To achieve the above-mentioned purpose, the utility model adopts the following technical scheme: a wireless stacked energy storage device, comprising a plurality of power supply devices arranged from top to bottom, a fixing mechanism is provided between any two adjacent power supply devices, the fixing mechanism comprises slots and plug-ins respectively arranged on the two power supply devices, an elastic reset member is provided between the plug-in board and the power supply device, and a magnet part is fixed on the plug-in board, the magnet part is provided with an electromagnet for use in conjunction with it, the electromagnet cooperates with the elastic reset member to enable the plug-in board to be telescopically arranged to be plugged in or separated from the slot.

[0008] Principle of the utility model:

[0009] When the number of power supply devices is two, an energy storage device and a power pack stacked up and down are used; if the number of power supply devices is more than two, one of the power supply devices is an energy storage device, and the other power supply devices are multiple power packs stacked in sequence along the energy storage device. Any two adjacent power supply devices are provided with an AC socket and an AC plug for use, ensuring that the two adjacent power supply devices can be connected in series or in parallel, avoiding the problem of cumbersome cable storage caused by the addition of cables. In order to achieve rapid fixation between two adjacent power supply devices, the utility model improves the fixed structure in the prior art, and uses the structure of the slot and the plug board to achieve the fixation of the two adjacent power supply devices, and the movement of the plug board is driven by an electromagnet. When in use, when the power supply device at the upper position is connected to the power supply device at the lower position, the power supply of the electromagnet is energized, and then the plug board is driven to move so that the plug board is plugged into the slot to achieve a fixed connection between the two adjacent power supply devices; when the power supply device needs to be replaced, the power supply of the electromagnet is turned off, and the plug board is reset and separated from the slot under the action of the elastic reset member, so as to unlock the two adjacent power supply devices.

[0010] Compared with the prior art, the utility model has the following beneficial effects:

[0011] The utility model improves the fixing structure in the prior art, and the power on and off of the electromagnet can be achieved by a switch button, so the plugging in or separation of the plug board and the slot can be achieved by simply pressing the switch button, making the fixing and unlocking between two adjacent power supply devices more convenient, and eliminating the need for an operator to repeatedly turn a screw rod to lock or unlock two adjacent power supply devices, making the loading and unloading of the stacked energy storage device arranged in the utility model more convenient.

[0012] Furthermore, the plug board slides horizontally to be connected or separated from the slot, the magnet part is a magnet plate fixedly connected to the plug board, the elastic reset member is a telescopic spring provided for use with the plug board, one end of the telescopic spring is fixed to the plug board, and the other end is relatively fixed to the power supply device.

[0013] Furthermore, the plug board includes a strip-shaped structure and a limit card plate that is plugged into the slot. An extended connecting section is provided at one end of the limit card plate away from the slot. The magnet plate is fixed to the connecting section and is vertically fixed to the connecting section and is arranged opposite to the electromagnet.

[0014] Furthermore, the plug board is provided with a mounting base for use therewith, the mounting base comprising a main base with a through slot structure and a fixed base fixed at one end of the main base, the plug board is slidably arranged with the main base along the through slot direction of the main base, the main base is fixedly connected to the power supply equipment, and the electromagnet is fixed to the main base; the other end of the telescopic spring is fixedly connected to the fixed base.

[0015] Furthermore, the two side walls of the main seat are bent inwards relative to each other and form a sliding groove with the bottom of the main seat groove for the plug-in board to slide. Fixed plates extending outwards relative to each other are respectively provided on the two side walls of the main seat, and the fixed plates are fixedly connected to the power supply equipment.

[0016] Furthermore, the fixed seat includes two connecting plates arranged opposite to each other and a transition plate fixed between the two connecting plates. Any connecting plate is parallel to the through-slot end of the main seat and is fixed to the main seat. A plug hole for the plug plate to slide is provided on the connecting plate. The magnet plate and the telescopic spring are both arranged between the two connecting plates, wherein one end of the telescopic spring is fixed to the plug plate, and the other end is fixed to the other connecting plate.

[0017] Furthermore, a recessed groove and a raised cavity for stacking positioning are provided between two adjacent power supply devices, wherein the slot is provided on the inner wall of the recessed groove or the outer wall of the raised cavity, and the plug board is telescopically provided with the side wall of the raised cavity or telescopically provided along the side wall of the recessed groove.

[0018] Furthermore, a plurality of groups of matched concave grooves and convex cavities are provided between two adjacent power supply devices, and a fixing mechanism is provided between each group of matched concave grooves and convex cavities.

[0019] Furthermore, a plurality of grooves are provided on the side wall of the concave groove, and a guide roller is provided in each groove for use in conjunction with the side wall of the convex cavity. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of the structure of two power supply devices provided for the utility model;

[0021] Figure 2 for Figure 1 Schematic diagram of the explosion structure;

[0022] Figure 3 A schematic diagram of the explosion structure of the utility model with three power supply devices;

[0023] Figure 4 It is a structural schematic diagram of the top plate of the power pack of the utility model;

[0024] Figure 5This is a top view of the structure of the bottom plate of the energy storage device of the utility model;

[0025] Figure 6 for Figure 5 Bottom view in

[0026] Figure 7 This is a schematic diagram of the structure of the plug board, the mounting seat, the electromagnet and the telescopic spring of the utility model;

[0027] Figure 8 for Figure 7 A schematic diagram of the structure from another perspective;

[0028] Fig. 9 It is a schematic diagram of the explosion structure of the plug board, mounting seat, electromagnet and telescopic spring of the utility model;

[0029] Fig.10 It is a structural schematic diagram of the mounting seat of the utility model.

[0030] In the figure: energy storage device 1, bottom plate 10, recessed groove 11, guide roller 12, screw 13, groove 14, power pack 2, top plate 20, protruding cavity 21, slot 31, electromagnet 32, plug plate 33, limit card plate 331, connecting section 332, magnet plate 34, telescopic spring 35, main seat 36, fixing plate 361, slide groove 362, fixing seat 37, connecting plate 371, transition plate 372, and socket 373. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0032] like Figure 1 , 2As shown in Figure 3, a wireless stacked energy storage device includes a plurality of power supply devices arranged from top to bottom, and the number of power supply devices arranged in the utility model is at least two. When the number of power supply devices is two, an energy storage device 1 and a power pack 2 stacked up and down are used; if the number of power supply devices is more than two, one of the power supply devices is an energy storage device 1, and the other power supply devices are a plurality of power packs 2 stacked in sequence along the energy storage device 1. Between any two adjacent power supply devices, there are provided an AC socket and an AC plug for use in conjunction with a POGOPIN and a signal transmission socket for use in conjunction, to ensure that the two adjacent power supply devices can be connected in series or in parallel, and to avoid the problem of cumbersome cable storage caused by additional cables. The number of power supply devices is set according to the needs of use, and it is sufficient to meet the power supply needs in specific situations. In this embodiment, two power supply devices stacked up and down are provided, and the two power supply devices are a power pack 2 arranged at the lower position and an energy storage device 1 arranged at the upper position.

[0033] In order to ensure more accurate positioning of the energy storage device 1 and the power pack 2 when they are stacked up and down, so as to facilitate the connection between the AC socket and the AC plug, a convex cavity 21 and a concave groove 11 for use together are provided between the energy storage device 1 and the power pack 2. The convex cavity 21 can be set at the top of the power pack 2 or the bottom of the energy storage device 1. The cooperation of the convex cavity 21 and the concave groove 11 can achieve positioning. In this embodiment, a concave groove 11 that is concave inward is provided on the bottom plate 10 of the energy storage device 1, and a convex cavity 21 that is convex upward is provided on the top of the power pack 2. The cooperation of the convex cavity 21 and the concave groove 11 facilitates the positioning of the energy storage device 1 and the power pack 2 when they are connected, and facilitates the connection between the AC socket and the AC plug. The number of the concave groove 11 and the convex cavity 21 can be set according to the use requirements, and can be one or more. For example Figure 2-6 As shown, in this embodiment, two concave grooves 11 and two convex cavities 21 are provided.

[0034] In order to facilitate the guidance of the concave groove 11 and the convex cavity 21, a plurality of grooves 14 are provided on the side wall of the concave groove 11, and a guide roller 12 is provided in each groove 14 for use with the side wall of the convex cavity 21. The setting of the guide roller 12 can play a guiding role when the convex cavity 21 and the concave groove 11 are plugged in, so that the plugging process can be smoother. Figure 5 As shown, when the guide roller 12 is installed, the guide roller 12 is sleeved on the screw 13, and the guide roller 12 is partially embedded in the groove 14, and the size of the groove 14 is adapted to the thickness of the guide roller 12. At the same time, the screw 13 is fixed to the bottom plate 10 of the energy storage device 1, so that the guide roller 12 can be connected to the recessed groove 11 and can be rolled under the action of the raised cavity 21.

[0035] In order to achieve the stability of the energy storage device 1 and the power pack 2 when they are connected, and to prevent the stacked packs from shaking or falling off during input and output, which may cause accidents, a fixing mechanism is provided between the energy storage device 1 and the power pack 2. Figure 4-10 As shown, the fixing mechanism includes a slot 31 and a plug-in board 33, wherein an elastic reset member is provided between the plug-in board 33 and the power supply device, and a magnet portion is fixed on the plug-in board 33, wherein the magnet portion is provided with an electromagnet 32 ​​for use in conjunction with the electromagnet 32, and the electromagnet 32 ​​cooperates with the elastic reset member to enable the plug-in board 33 to be telescopically arranged to be plugged in or separated from the slot 31. Among them, the slot 31 can be arranged on the power pack 2 or on the energy storage device 1, and correspondingly, the plug-in board 33 is arranged on the energy storage device 1 or the power pack 2, so as to ensure that when the plug-in board 33 is plugged in the slot 31, the energy storage device 1 and the power pack 2 can be fixed; and the setting position of the plug-in board 33 can be on the top plate 20 or side wall of the power pack 2, or on the bottom plate 10 or side wall of the energy storage device 1, so as to ensure that the cooperation between the plug-in board 33 and the slot 31 can lock or unlock the power pack 2 and the energy storage device 1. According to the structure of the plug-in board 33, the plug-in board 33 can be arranged vertically, tilted or horizontally. When the plug board 33 is a rigid structure, the plug board 33 is tilted or horizontally set to cooperate with the slot 31 to lock the energy storage device 1 and the power pack 2 stacked up and down; if a deformation part (rubber, silicone, etc.) is set at the end of the plug board 33 inserted into the slot 31, and a convex groove is set at the bottom of the slot 31, then even if the plug board 33 is set vertically, when the deformation part of the plug board 33 enters the convex groove and is squeezed and deformed in the convex groove, at this time, as long as the plug board 33 does not move, the plug board 33 and the slot 31 can also be used to lock the energy storage device 1 and the power pack 2 stacked up and down. The movement of the plug board 33 is driven by the electromagnet 32. During use, when the power supply device at the upper position is connected to the power supply device at the lower position, the power supply of the electromagnet 32 ​​is energized, thereby driving the plug board 33 to move so that the plug board 33 is plugged into the slot 31, thereby achieving a fixed connection between the two adjacent power supply devices; when the power supply device needs to be replaced, the power supply of the electromagnet 32 ​​is cut off, and the plug board 33 is reset and separated from the slot 31 under the action of the elastic reset member, thereby unlocking the two adjacent power supply devices.

[0036] The utility model improves the fixing structure in the prior art, and the power on and off of the electromagnet 32 ​​can be achieved by a switch button, and the plugging or separation of the plug board 33 and the slot 31 can be achieved by simply pressing the switch button, making the fixing and unlocking between the two adjacent power supply devices more convenient, without the need for the operator to repeatedly turn the screw to lock the two adjacent power supply devices or unlock the two adjacent power supply devices, making the loading and unloading of the stacked energy storage device arranged in the utility model more convenient.

[0037] Furthermore, the fixing mechanism is used in conjunction with the protruding cavity 21 and the concave groove 11, the slot 31 is arranged on the inner wall of the concave groove 11 or the outer wall of the protruding cavity 21, and the plug plate 33 is arranged telescopically with the side wall of the protruding cavity 21 or along the side wall of the concave groove 11. Figure 6 As shown, in this embodiment, the inserting plate 33 penetrates through the side wall of the recessed groove 11 and is telescopically arranged along the side wall of the recessed groove 11 , and the insertion slot 31 is arranged in a recessed manner on the outer wall of the raised cavity 21 .

[0038] Furthermore, in this embodiment, the plug board 33 is a rigid structure, and the plug board 33 slides horizontally to be plugged into or separated from the slot 31. Figure 7 , 8 As shown, in order to realize the movement of the plug board 33 under the electromagnet 32, the magnet part arranged on the plug board 33 is a magnet plate 34 fixedly connected to the plug board 33; the electromagnet 32 ​​can absorb the magnet plate 34 when it is energized, thereby driving the plug board 33 to move and plug into the slot 31. In order to realize that the plug board 33 can be reset when the electromagnet 32 ​​is powered off, the elastic reset member of this embodiment is a telescopic spring 35 used in conjunction with the plug board 33, one end of the telescopic spring 35 is fixed to the plug board 33, and the other end is relatively fixed to the power supply device; when the electromagnet 32 ​​is powered off, the plug board 33 is reset and separated from the slot 31 under the action of the telescopic spring 35, which can realize the separation of the energy storage device 1 and the power pack 2, and facilitate the loading and unloading or replacement of any device.

[0039] Furthermore, in order to realize the horizontal sliding of the plug plate 33, the plug plate 33 provided in the utility model is provided with a mounting seat for use therewith, and the mounting seat includes a main seat 36 with a through-slot structure and a fixed seat 37 fixed at one end of the main seat 36. The plug plate 33 is slidably arranged with the main seat 36 along the through-slot direction of the main seat 36, the main seat 36 is fixedly connected to the power supply equipment, and the electromagnet 32 ​​is fixed to the main seat 36; the other end of the telescopic spring 35 is fixedly connected to the fixed seat 37. The through-slot direction of the main seat 36 is arranged horizontally, and the plug plate 33 is inserted along the through-slot direction of the main seat 36. In order to make the plug plate 33 and the main seat 36 slide, the main seat 36 can be directly arranged into a wedge groove or a dovetail groove structure, and a slider that cooperates with the main seat 36 is arranged on the plug plate 33, so that the sliding connection between the plug plate 33 and the main seat 36 can be realized. In this embodiment, Fig. 9 , 10 As shown, the two side walls of the main seat 36 are relatively bent inward and form a slide groove 362 with the bottom of the main seat 36 for the plug plate 33 to slide; the plug plate 33 is a plate-shaped structure and is inserted into the slide groove 362 to achieve the sliding connection between the plug plate 33 and the main seat 36. The main seat 36 needs to be fixed to the bottom plate 10 of the energy storage device 1. For this purpose, fixed plates 361 extending relatively outward are respectively provided on the two side walls of the main seat 36. The fixed plates 361 are fixedly connected to the bottom plate 10 of the energy storage device 1 by bolts.

[0040] To match the main seat 36 of the above structure, Fig. 9 ,10 As shown, the fixed seat 37 provided in the utility model includes two connecting plates 371 arranged opposite to each other and a transition plate 372 fixed between the two connecting plates 371. Any connecting plate 371 is parallel to the through-slot end of the main seat 36 and is fixed to the main seat 36. A plug hole 373 for the plug plate 33 to slide is provided on the connecting plate 371. The magnet plate 34 and the telescopic spring 35 are arranged between the two connecting plates 371, wherein one end of the telescopic spring 35 is fixed to the plug plate 33 and the other end is fixed to the other connecting plate 371. The fixed seat 37 is fixedly arranged with the main seat 36. When the main seat 36 is fixed to the bottom plate 10 of the energy storage device 1, the fixed seat 37 can also be fixedly connected with the bottom plate 10 of the energy storage device 1, thereby ensuring that the other end of the telescopic spring 35 is relatively fixed to the bottom plate 10 of the energy storage device 1, so that the plug plate 33 can be reset under the action of the telescopic spring 35 after moving.

[0041] In order to make the cooperation between the electromagnet 32 ​​and the magnet plate 34 smoother and facilitate the installation of the electromagnet 32, as shown in FIG. Figure 7-9 As shown, in this embodiment, the electromagnet 32 ​​is fixed to the outer bottom of the main seat 36, and the plug board 33 includes a bar-shaped structure and a limit card plate 331 that is plugged and matched with the slot 31. An extended connecting section 332 is provided at one end of the limit card plate 331 away from the slot 31, and the magnet plate 34 is fixed to the connecting section 332 and is vertically fixed to the connecting section 332 and is arranged opposite to the electromagnet 32. The plug board 33 of this structure can facilitate the installation of the magnet plate 34 and the limiting of the plug board 33 when it moves, so as to prevent the plug board 33 from being separated from the main seat 36 under the action of the telescopic spring 35 when the electromagnet 32 ​​is powered off.

[0042] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-restrictive from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention. Any reference numeral in a claim should not be regarded as limiting the claim to which it relates.

Claims

1. A wireless stacked energy storage device, comprising a plurality of power supply devices arranged from top to bottom, wherein a fixing mechanism is provided between any two adjacent power supply devices, characterized in that: The fixing mechanism comprises a slot (31) and a plug board (33) respectively arranged on two power supply devices, an elastic reset member is arranged between the plug board (33) and the power supply device, and a magnet part is fixed on the plug board (33), the magnet part is provided with an electromagnet (32) for use with the plug board, and the electromagnet (32) cooperates with the elastic reset member to enable the plug board (33) to be telescopically arranged to be plugged into or separated from the slot (31).

2. A wireless stacking energy storage device according to claim 1, characterized in that: The plug board (33) slides horizontally to be plugged into or separated from the slot (31); the magnet portion is a magnet plate (34) fixedly connected to the plug board (33); the elastic reset member is a telescopic spring (35) provided on the plug board (33) for use in conjunction with the plug board (33); one end of the telescopic spring (35) is fixed to the plug board (33) and the other end is relatively fixed to the power supply device.

3. A wireless stacking energy storage device according to claim 2, characterized in that: The plug plate (33) comprises a bar-shaped structure and a limit card plate (331) plugged into and matched with the slot (31); an extended connecting section (332) is provided at one end of the limit card plate (331) away from the slot (31); the magnet plate (34) is fixed to the connecting section (332) and is vertically fixed to the connecting section (332) and is arranged opposite to the electromagnet (32).

4. A wireless stacking energy storage device according to claim 2 or 3, characterized in that: The plug board (33) is provided with a mounting seat for use therewith, the mounting seat comprising a main seat (36) with a through slot structure and a fixed seat (37) fixed to one end of the main seat (36), the plug board (33) is slidably arranged with the main seat (36) along the through slot direction of the main seat (36), the main seat (36) is fixedly connected to the power supply device, and the electromagnet (32) is fixed to the main seat (36); the other end of the telescopic spring (35) is fixedly connected to the fixed seat (37).

5. A wireless stacking energy storage device according to claim 4, characterized in that: The two side walls of the main seat (36) are relatively bent inwards and together with the groove bottom of the main seat (36) form a slide groove (362) for the plug board (33) to slide. The two side walls of the main seat (36) are respectively provided with fixed plates (361) extending relatively outwards, and the fixed plates (361) are fixedly connected to the power supply equipment.

6. A wireless stacking energy storage device according to claim 4, characterized in that: The fixed seat (37) comprises two connecting plates (371) arranged opposite to each other and a transition plate (372) fixed between the two connecting plates (371). Any connecting plate (371) is parallel to the through-slot end of the main seat (36) and is fixed to the main seat (36). A plug hole (373) for sliding the plug plate (33) is provided on the connecting plate (371). The magnet plate (34) and the telescopic spring (35) are arranged between the two connecting plates (371), wherein one end of the telescopic spring (35) is fixed to the plug plate (33), and the other end is fixed to the other connecting plate (371).

7. A wireless stacking energy storage device according to claim 5, characterized in that: The fixed seat (37) comprises two connecting plates (371) arranged opposite to each other and a transition plate (372) fixed between the two connecting plates (371). Any connecting plate (371) is parallel to the through-slot end of the main seat (36) and is fixed to the main seat (36). A plug hole (373) for sliding the plug plate (33) is provided on the connecting plate (371). The magnet plate (34) and the telescopic spring (35) are arranged between the two connecting plates (371), wherein one end of the telescopic spring (35) is fixed to the plug plate (33), and the other end is fixed to the other connecting plate (371).

8. A wireless stacking energy storage device according to claim 1, 2, 3, 5, 6 or 7, characterized in that: A recessed groove (11) and a raised cavity (21) for stacking and positioning are also provided between two adjacent power supply devices, wherein the slot (31) is provided on the inner wall of the recessed groove (11) or the outer wall of the raised cavity (21), and the plug plate (33) is telescopically provided with the side wall of the raised cavity (21) or with the side wall along the recessed groove (11).

9. A wireless stacking energy storage device according to claim 8, characterized in that: A plurality of groups of matched concave grooves (11) and convex cavities (21) are provided between two adjacent power supply devices, and a fixing mechanism is provided between each group of matched concave grooves (11) and convex cavities (21).

10. A wireless stacking energy storage device according to claim 9, characterized in that: A plurality of grooves (14) are provided on the side wall of the concave groove (11), and a guide roller (12) is provided in each groove (14) for use in conjunction with the side wall of the convex cavity (21).

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