A new energy vehicle battery testing device

Abstract

The present invention belongs to the field of battery detection technology, and relates to a new energy vehicle battery detection device, comprising a conveying group 1, a conveying group 2, a control console provided on the conveying group 2, and a connection frame connected between the conveying group 1 and the conveying group 2. A weighing device and two opposing cylinders 1 are installed at the lower part of the connection frame. The weighing device and the cylinder 1 are both electrically connected to a controller built into the control console. The telescopic end of the cylinder 1 is connected to a support column located above the weighing device and vertically offset from the weighing device. The battery on the conveying group 1 is pushed right onto the support column for detection and then pushed right onto the conveying group 2 for transportation, thereby automatically performing continuous battery detection. The weighing device automatically completes weighing before detection, and then the contact piece moves downward to perform fault detection with the battery electrode. The degree of automation is high, and the contact piece is automatically disengaged and the battery is removed after detection.

Description

Technical Field

[0001] The present invention belongs to the technical field of battery detection, and in particular relates to a new energy vehicle battery detection device. Background Art

[0002] As a core component of new energy vehicles, battery performance directly impacts the vehicle's range, safety, and service life. Therefore, battery quality testing is essential. Existing testing methods typically involve electrically connecting testing equipment to the battery's electrodes to perform charge and discharge tests.

[0003] Most existing technologies use a testing bench for testing, which is cumbersome to take and place, and cannot perform testing continuously and automatically. For example, patent publication number CN218974420U discloses an automotive lithium battery insulation testing workbench. When in use, the testing workbench contacts the lithium battery shell through a probe to complete the test. However, the battery on the battery placement plate is manually taken and placed, and the weight of the battery cannot be automatically detected during testing. It is impossible to know whether there is a fault of lack of electrolyte, which has limitations.

[0004] In view of the shortcomings of the above-mentioned prior art, a new energy vehicle battery testing device is designed to overcome the shortcomings of the prior art. It can perform continuity testing at the same time, automatically complete weighing before testing, and automatically disengage the contact plate and remove the battery after testing. Summary of the Invention

[0005] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a new energy vehicle battery testing device that can perform continuity testing at the same time, automatically complete weighing before testing, and automatically disengage the contact piece and remove the battery after testing.

[0006] In order to solve the above technical problems, the present invention provides a new energy vehicle battery testing equipment, including a conveying group 1, a conveying group 2 parallel to the right of the conveying group 1, a control console arranged on the conveying group 2, and a connecting frame connected between the conveying group 1 and the conveying group 2. The connecting frame has a row of shaft rollers for assisting in conveying batteries near the position of the conveying group 1. A weighing device and two cylinders 1 facing each other are installed at the lower part of the connecting frame. The weighing device and the cylinder 1 are electrically connected to the controller built into the control console. The weighing device is used to accurately weigh the battery. The telescopic ends of the two cylinders 1 are connected to the weighing A support column is above the weighing device and staggered with the weighing device in the vertical direction. The pushing assembly provided on the conveying group 1 pushes the battery conveyed by the conveying group 1 from the connecting frame to the conveying group 2. The upper part of the connecting frame slides with two lifting frames facing each other front and back. The upper end of the lifting frame is connected with a contact piece for contacting the electrode of the battery. A spring 1 surrounding the lifting frame is connected between the lifting frame and the connecting frame. The spring 1 is used to allow the downward-moving lifting frame to move upward for reset. The two support columns are connected to a resistance block sliding through the connecting frame on the side away from each other. The lower end of the lifting frame has an inverted T-shaped portion suitable for contacting and cooperating with the upper side of the resistance block.

[0007] Preferably, it also includes a leakage detection needle slidably arranged on the upper front side of the connecting frame, the leakage detection needle is perpendicular to the connecting frame, the leakage detection needle is used to detect whether the battery shell is leaking, the leakage detection needle is electrically connected to the controller built into the console, and a transmission drive group for driving the leakage detection needle to contact the battery shell is provided between the lifting frame and the leakage detection needle.

[0008] Preferably, the transmission drive group includes a skateboard, a bracket portion is provided on one side of the connecting frame, the skateboard slides on the bracket portion, the leakage detection needle slides through the skateboard, one end of the leakage detection needle is sleeved with a retaining ring, and a spring 2 surrounding the leakage detection needle is connected between the retaining ring and the skateboard, the lower end of the skateboard is connected to a rack 1, and a gear that engages with the rack 1 rotates on the upper front side of the connecting frame, and a rack 2 suitable for engaging with the gear is connected to one of the two lifting frames.

[0009] Preferably, conveying group one includes a frame one perpendicular to the connecting frame, and a belt conveyor one for conveying batteries is installed on the frame one, and the upper side of the belt of the belt conveyor one is flush with the upper side of the shaft roller; conveying group two includes a frame two perpendicular to the connecting frame, and a belt conveyor two for conveying batteries is installed on the frame two, and the upper side of the belt of the belt conveyor two is flush with the upper side of the support column.

[0010] Preferably, the pushing component includes a support frame connected between the frame 1 and the connecting frame, an electric guide rail is installed on the upper part of the support frame, and a loading plate for pushing the battery is connected to the slider of the electric guide rail.

[0011] Preferably, it also includes a blocking frame slidingly arranged on the support frame, the sliding direction of the blocking frame is perpendicular to the conveying direction of the belt conveyor 1, the blocking frame is suitable for moving to the right to block the batteries conveyed on the belt conveyor 1, and a spring three is connected between the blocking frame and the support frame. The spring three is used to provide the blocking frame with force to move to the right to block the batteries, and the loading plate is in contact with the blocking frame.

[0012] Preferably, it also includes a baffle slidably arranged on the upper part of the connecting frame, the baffle is located on the side of the connecting frame close to the belt conveyor 2, the baffle is used to block the batteries on the support column to prevent them from being pushed directly onto the belt conveyor 2 by the loading plate, and the upper part of the frame 2 is installed with a cylinder 2, and the piston end of the cylinder 2 is connected to the baffle.

[0013] Preferably, it also includes three unloading groups arranged on the frame two, the unloading groups are used to discharge batteries that fail the inspection from the belt conveyor two, the unloading group includes a cylinder three installed on the frame two, the piston end of the cylinder three is connected to the unloading plate, the frame two is provided with an unloading port opposite to the unloading plate, and a limit plate is rotated on the unloading port of the frame two, the limit plate is used to limit and protect the batteries during the process of the belt conveyor two transporting the batteries backward, and a torsion spring is connected between the limit plate and the frame two to provide the limit plate with a vertical force to maintain the vertical force.

[0014] The present invention overcomes the shortcomings of the prior art and has the following beneficial effects:

[0015] The pushing component is used to push the battery on conveyor group 1 to the right onto the support column for testing, and then to the right onto conveyor group 2 for transportation, thereby automatically performing continuous battery testing; and the weighing device automatically completes weighing before testing, and then the contact piece moves down and contacts the battery electrode for fault detection, with a high degree of automation. After testing, the contact piece is automatically disengaged and the battery is removed. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is an assembly diagram of the present invention;

[0017] Figure 2 It is a rear side schematic diagram of the present invention;

[0018] Figure 3 Schematic diagram of the connecting frame, lifting frame and spring 1 of the present invention;

[0019] Figure 4 Schematic diagram of the internal structure of the connection frame of the present invention;

[0020] Figure 5 It is a cross-sectional view of the connecting frame of the present invention as viewed from the right side;

[0021] Figure 6 For the present invention Figure 3 A magnified view of point A;

[0022] Figure 7 Schematic diagram of the support frame, electric guide rail and loading plate of the present invention;

[0023] Figure 8 Schematic diagram of the retaining frame and spring three of the present invention;

[0024] Figure 9 Schematic diagram of the limiting plate and torsion spring of the present invention.

[0025] The marks in the drawings provided by the present invention are: 10-control console, 1-conveyor group 1, 11-frame 1, 12-belt conveyor 1, 2-conveyor group 2, 21-frame 2, 22-belt conveyor 2, 3-connecting frame, 30-axis roller, 31-weigher, 32-cylinder 1, 33-support column, 34-lifting frame, 35-contact piece, 36-spring 1, 37-resistance block, 4-leakage detection needle, 41-bracket, 42-slide plate, 43-blocking ring, 44-spring 2, 45-rack 1, 46-gear, 47-rack 2, 5-pushing assembly, 51-support frame, 52-electric guide rail, 53-loading plate, 54-blocking frame, 55-spring 3, 6-baffle, 61-cylinder 2, 71-cylinder 3, 72-unloading plate, 73-limiting plate, 74-torsion spring. DETAILED DESCRIPTION

[0026] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the present invention.

[0027] Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The technical solutions of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. It should be noted that the technical features involved in the different embodiments of the present invention described below may be combined with one another as long as they do not conflict with one another.

[0028] A new energy vehicle battery testing device, such as Figure 1-Figure 5As shown, it includes a conveying group 1, a conveying group 2 parallel to the right of the conveying group 1, a control console 10 provided on the conveying group 2, and a connecting frame 3 connected between the conveying group 1 and the conveying group 2. The connecting frame 3 has a row of rollers 30 for assisting in conveying batteries near the conveying group 1. A weighing device 31 and two cylinders 1 32 facing each other are installed at the lower part of the connecting frame 3. The weighing device 31 and the cylinder 1 32 are electrically connected to the controller built into the control console 10. The weighing device 31 is used to accurately weigh the battery to detect whether the battery has a liquid shortage or a low liquid fault. The telescopic ends of the two cylinders 1 32 are connected to a support column 33 located above the weighing device 31 and staggered in the vertical direction with the weighing device 31, which is provided at the bottom. The pushing component 5 on the conveying group 1 pushes the battery conveyed by the conveying group 1 from the connecting frame 3 to the conveying group 2 2, and controls the pushing component 5 to first push the battery on the conveying group 1 to the right to the top of the weighing device 31 on the connecting frame 3. At this time, the battery is located between the upper sides of the two support columns 33, and controls the cylinder 1 32 to drive the support column 33 to move the battery down to the weighing device 31 until the support column 33 continues to move down and releases the battery for automatic weighing, and causes friction to the asymmetrical weighing device 31. After weighing is completed, control the cylinder 1 32 to drive the support column 33 to move up and reset, driving the electrode to move up. At this time, control the pushing component 5 to push the battery on the support column 33 to the right to the conveying group 2 2, so that continuous battery detection can be automatically performed, and the connecting frame 3 The upper sliding part has two lifting frames 34 facing each other front and back. The upper end of the lifting frame 34 is connected with a contact piece 35 for contacting the electrode of the battery. The upper end of the contact piece 35 is electrically connected to the external detection equipment, and the lower end of the contact piece 35 is electrically connected to the electrode of the battery. In this way, when the two lifting frames 34 drive the two contact pieces 35 to move down and contact the positive and negative poles of the battery respectively, fault detection is performed. A spring 1 36 surrounding the lifting frame 34 is connected between the lifting frame 34 and the connecting frame 3. The spring 1 36 is used to move the lifting frame 34 upward for resetting. The two support columns 33 are connected to the side away from each other with a resistance block 37 that slides through the connecting frame 3. The lower end of the lifting frame 34 has an inverted T-shaped portion suitable for contacting and cooperating with the upper side of the resistance block 37. , when the support column 33 drives the battery to move down to the weighing device 31 for weighing detection and the detection is qualified, the weighing device 31 controls the cylinder 1 32 through the console 10 to continue to drive the support column 33 to drive the resistance block 37 to move down and push the inverted T-shaped part at the lower end of the lifting frame 34. At this time, the lifting frame 34 will drive the contact piece 35 to move down and perform fault detection with the battery electrode. After the detection is completed, the control cylinder 1 32 drives the support column 33 to drive the contact piece 35 to move up and release the lifting frame 34. The lifting frame 34 will drive the contact piece 35 to move up and reset to disengage the battery electrode under the action of the spring 1 36. The support column 33 continues to move up to drive the electrode to move up and disengage from the weighing device 31, thereby facilitating the automatic disengagement of the contact piece 35 after use and the automatic removal of the battery after detection.

[0029] like Figure 3 and Figure 6 As shown, it also includes a leakage detection needle 4 slidably arranged on the front side of the upper part of the connecting frame 3, the leakage detection needle 4 is perpendicular to the connecting frame 3, the leakage detection needle 4 is used to detect whether the battery shell is leaking, the leakage detection needle 4 is electrically connected to the controller built into the console 10, and a transmission drive group for driving the leakage detection needle 4 to contact the battery shell is provided between the lifting frame 34 and the leakage detection needle 4. When the battery is supported on the weighing device 31 and the lifting frame 34 drives the contact piece 35 to move down and contact the battery electrode for fault detection, the lifting frame 34 will move the leakage detection needle 4 backward through the transmission drive group to contact the battery shell, so as to detect whether the battery shell has a leakage fault. When the lifting frame 34 drives the contact piece 35 to move up and reset, the lifting frame 34 will also move the leakage detection needle 4 forward through the transmission drive group to loosen the battery shell, thereby realizing diversified detection and improving the detection effect.

[0030] like Figure 3 and Figure 6 As shown, the transmission drive group includes a slide plate 42, and a bracket portion 41 is provided on one side of the connecting frame 3. The slide plate 42 slides on the bracket portion 41, and the leakage detection needle 4 slides through the slide plate 42. The slide plate 42 drives the leakage detection needle 4 to move backward and contact the battery shell on the weighing device 31. One end of the leakage detection needle 4 is sleeved with a retaining ring 43, and a spring 2 44 surrounding the leakage detection needle 4 is connected between the retaining ring 43 and the slide plate 42. The spring 2 44 is suitable for making the leakage detection needle 4 adaptively contact the battery shell to avoid excessive collision of the leakage detection needle 4 with the battery shell. The lower end of the slide plate 42 is connected with a rack 1 45, and the connecting frame 3 A gear 46 that engages with rack 1 45 rotates on the front side of the upper portion. The rotation of gear 46 drives rack 1 45 to move backward, and rack 1 45 drives slide 42 to move backward. One of the two lifting frames 34 is connected to rack 2 47 that is suitable for engaging gear 46. Therefore, when the lifting frame 34 drives the contact piece 35 to move downward to contact the battery electrode, the lifting frame 34 also drives rack 2 47 to move downward to engage gear 46, so that gear 46 drives rack 1 45 to move backward. When the contact piece 35 contacts the battery electrode for fault detection, the leakage detection needle 4 is automatically and synchronously caused to contact the battery casing for leakage detection.

[0031] like Figure 2As shown, conveying group 1 includes a frame 11 perpendicular to the connecting frame 3, and a belt conveyor 12 for conveying batteries is installed on the frame 11. The upper side of the belt of the belt conveyor 12 is flush with the upper side of the shaft roller 30, so that the pushing component 5 can push the batteries conveyed on the belt conveyor 12 smoothly to the right to the shaft roller 30 and the support column 33; conveying group 2 includes a frame 21 perpendicular to the connecting frame 3, and a belt conveyor 22 for conveying batteries is installed on the frame 21, and the upper side of the belt of the belt conveyor 22 is flush with the upper side of the support column 33, so that the pushing component 5 can push the batteries inspected on the support column 33 smoothly to the right to the belt conveyor 22 for conveyance.

[0032] like Figure 2 and Figure 7 As shown, the pushing assembly 5 includes a support frame 51 connected between the frame 11 and the connecting frame 3, and an electric guide rail 52 is installed on the upper part of the support frame 51. The slider of the electric guide rail 52 is connected to a loading plate 53 for pushing the battery. When the belt conveyor 12 is controlled to transport the battery backward to the right of the loading plate 53, the electric guide rail 52 is controlled to drive the loading plate 53 to push the battery through the shaft roller 30 to the right to the support column 33 for inspection. After the inspection is completed and the support column 33 moves up and reset, the electric guide rail 52 is controlled again to drive the loading plate 53 to move right to push the battery to the belt conveyor 2 22. At this time, the belt conveyor 2 22 is controlled to transport the inspected battery backward.

[0033] like Figure 7 and Figure 8 As shown, it also includes a blocking frame 54 slidingly arranged on the support frame 51, and the sliding direction of the blocking frame 54 is perpendicular to the conveying direction of the belt conveyor 12. The blocking frame 54 is suitable for moving right to block the batteries transported on the belt conveyor 12. A spring three 55 is connected between the blocking frame 54 and the support frame 51. The spring three 55 is used to provide the blocking frame 54 with a force to move right to block the batteries. The loading plate 53 contacts and cooperates with the blocking frame 54. Initially, the loading plate 53 squeezes the blocking frame 54, and the spring three 55 is in a deformed state. When the belt conveyor 12 moves the battery backward to the right of the loading plate 53, the electric guide rail 52 is controlled to drive the loading plate 53 to move right to push the battery to the support column 33. At the same time, the loading plate 53 will release the blocking frame 54, and the spring three 55 will reset. The blocking frame 54 will move right under the action of the reset of the spring three 55 to block the belt conveyor 12, thereby preventing the belt conveyor 12 from continuing to transport the battery backward.

[0034] like Figure 2 and Figure 3As shown, it also includes a baffle 6 that is slidably arranged on the upper part of the connecting frame 3. The baffle 6 is located on the side of the connecting frame 3 close to the belt conveyor 22. The baffle 6 is used to block the batteries on the support column 33 to prevent them from being directly pushed to the belt conveyor 22 by the loading plate 53. A cylinder 2 61 is installed on the upper part of the frame 21. The piston end of the cylinder 2 61 is connected to the baffle 6. When the battery detection is completed and the loading plate 53 needs to push the battery on the support column 33 to the belt conveyor 22, the cylinder 2 61 is controlled to drive the baffle 6 to move backward to open the baffle 6 for the battery to be transferred from the support column 33 to the belt conveyor 22.

[0035] like Figure 2 and Figure 9 As shown, it also includes three blanking groups arranged on the frame 21, and the blanking group is used to discharge the unqualified batteries from the belt conveyor 22. The blanking group includes a cylinder 3 71 installed on the frame 21, and the piston end of the cylinder 3 71 is connected to the blanking plate 72. The frame 21 is provided with a blanking port opposite to the blanking plate 72. When the belt conveyor 22 conveys the unqualified batteries backward to the right of the blanking plate 72, the belt conveyor 22 is controlled to stop, and then the cylinder 3 71 is controlled to drive the blanking plate 72 to move right to push the unqualified batteries out of the blanking port, thereby facilitating the discharge of the unqualified batteries. The limit plate 73 is rotated on the blanking port of the frame 21, and the limit plate 73 is used In order to limit and protect the batteries during the process of the belt conveyor 22 conveying the batteries backward, a torsion spring 74 is connected between the limit plate 73 and the frame 21 to provide a vertical force for the limit plate 73. When the unloading plate 72 moves to the right to push out the battery that fails the inspection, the limit plate 73 will be squeezed by the battery and rotated open, and the torsion spring 74 will deform until the battery is pushed out and the torsion spring 74 resets. The limit plate 73 will rotate in the opposite direction and reset and close under the action of the torsion spring 74 resetting. It should be explained that, by using three unloading groups, batteries that fail the weighing, fail the inspection when the contact piece 35 contacts the electrode, and fail the inspection when the leakage detection needle 4 contacts the shell can be classified and discharged respectively.

[0036] Obviously, the embodiments described above are only part of the embodiments of the present invention, rather than all the embodiments. They only express the preferred implementation methods of the present invention and the description is relatively specific and detailed, but they cannot be understood as limiting the patent scope of the present invention.

[0037] It should be pointed out that, for ordinary technicians in this field, several variations, increases and decreases in quantity, improvements and substitutions can be made without departing from the concept of the present invention. Therefore, based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work are within the scope of protection of the present invention.

Claims

1. A new energy vehicle battery testing device, characterized in that: The invention comprises a conveying group 1 (1), a conveying group 2 (2), a control console (10) arranged on the conveying group 2 (2), and a connecting frame (3) connected between the conveying group 1 (1) and the conveying group 2 (2). The connecting frame (3) has a row of shaft rollers (30) at a position close to the conveying group 1 (1). A weighing device (31) and two opposite cylinders (32) are installed at the lower part of the connecting frame (3). The weighing device (31) and the cylinder (32) are both electrically connected to the controller built into the control console (10). The telescopic end of the cylinder (32) is connected to a device located above the weighing device (31) and connected to the weighing device (31). The supporting columns (33) are staggered in the vertical direction, and the pushing assembly (5) provided on the conveying group (1) pushes the batteries conveyed by the conveying group (1) from the connecting frame (3) to the conveying group (2). Two lifting frames (34) facing each other are slidably mounted on the connecting frame (3). The upper end of the lifting frame (34) is connected to a contact piece (35). A spring (36) is connected between the lifting frame (34) and the connecting frame (3). A resistance block (37) is connected to one side of the supporting column (33). The lower end of the lifting frame (34) has an inverted T-shaped portion suitable for contacting and cooperating with the upper side of the resistance block (37). It also includes a leakage detection needle (4) slidably arranged on the connecting frame (3), the leakage detection needle (4) is perpendicular to the connecting frame (3), the leakage detection needle (4) is used to detect whether the battery shell is leaking, the leakage detection needle (4) is electrically connected to the controller built into the console (10), and a transmission drive group for driving the leakage detection needle (4) to contact the battery shell is provided between the lifting frame (34) and the leakage detection needle (4); The transmission drive group includes a slide plate (42), a bracket portion (41) is provided on one side of the connecting frame (3), the slide plate (42) slides on the bracket portion (41), the leakage detection needle (4) slides through the slide plate (42), one end of the leakage detection needle (4) is sleeved with a retaining ring (43), a spring 2 (44) is connected between the retaining ring (43) and the slide plate (42), the lower end of the slide plate (42) is connected with a rack 1 (45), the upper front side of the connecting frame (3) is rotated with a gear (46) engaged with the rack 1 (45), and the lifting frame (34) is connected with a rack 2 (47) suitable for engaging with the gear (46).

2. A new energy vehicle battery testing device according to claim 1, characterized in that: The conveying group 1 (1) includes a frame 1 (11) perpendicular to the connecting frame (3), and a belt conveyor 1 (12) for conveying batteries is installed on the frame 1 (11), and the upper side of the belt of the belt conveyor 1 (12) is flush with the upper side of the shaft roller (30); the conveying group 2 (2) includes a frame 2 (21) perpendicular to the connecting frame (3), and a belt conveyor 2 (22) for conveying batteries is installed on the frame 2 (21), and the upper side of the belt of the belt conveyor 2 (22) is flush with the upper side of the support column (33).

3. A new energy vehicle battery testing device according to claim 2, characterized in that: The pushing assembly (5) includes a support frame (51) connected between the frame 1 (11) and the connecting frame (3), an electric guide rail (52) is installed on the upper part of the support frame (51), and a loading plate (53) is connected to the slider of the electric guide rail (52).

4. A new energy vehicle battery testing device according to claim 3, characterized in that: It also includes a blocking frame (54) slidably arranged on the support frame (51), the sliding direction of the blocking frame (54) is perpendicular to the conveying direction of the belt conveyor (12), the blocking frame (54) is suitable for blocking the batteries conveyed on the belt conveyor (12), a spring (55) is connected between the blocking frame (54) and the support frame (51), and the loading plate (53) is in contact with the blocking frame (54).

5. A new energy vehicle battery testing device according to claim 2, characterized in that: It also includes a baffle (6) slidably mounted on the connecting frame (3), the baffle (6) being located on a side of the connecting frame (3) close to the second belt conveyor (22), the baffle (6) being used to block the battery on the support column (33), the second frame (21) being mounted with a second cylinder (61), the piston end of the second cylinder (61) being connected to the baffle (6).

6. A new energy vehicle battery testing device according to claim 2, characterized in that: It also includes three unloading groups arranged on the frame 2 (21), and the unloading groups are used to discharge unqualified batteries from the belt conveyor 2 (22). The unloading group includes a cylinder 3 (71) installed on the frame 2 (21), and the piston end of the cylinder 3 (71) is connected to a unloading plate (72). The frame 2 (21) is provided with an unloading port opposite to the unloading plate (72). A limit plate (73) is rotated on the unloading port of the frame 2 (21), and a torsion spring (74) is connected between the limit plate (73) and the frame 2 (21).

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