Safety auxiliary stair

Abstract

The invention relates to the technical field of crawling ladders, in particular to a safety auxiliary stair which comprises a stair frame and a mounting assembly. The ladder assembly comprises vertical rods, handrails and supporting pipes. And the mounting assembly comprises a connecting rod and a mounting block. By means of the design of the screw holes in the original tailgate, the stairway can be rapidly fixed. The handrails on the two sides of the stair are designed to be retractable, storage space is saved, carrying is convenient, and practicability is enhanced. The installation assembly enables the position of the installation connecting rod to be fixed when the bolt is connected with the bolt hole in the tailgate, operation is further simplified, and installation efficiency and stability are improved. The stair is made of stainless steel, firmness and durability of the structure are guaranteed, and the stair is suitable for being used in different environments. The auxiliary stair is simple in structure, convenient to install, stable and reliable, the psychological stress and physical burden of operators can be remarkably reduced, and the safety and efficiency of maintenance work are improved.

Description

Technical Field

[0001] The invention relates to the technical field of ladders, in particular to a safety auxiliary staircase. Background Art

[0002] In the maintenance and overhaul of modern hydroelectric generating units, entering the tailwater pipe for inspection has always been an important and challenging task. The traditional method usually uses soft stairs to allow workers to enter the tailwater pipe, but this method requires greater physical support, and auxiliary personnel are required to assist in pulling the safety rope to ensure the safety of personnel. However, this method is not only inefficient, but also has great safety hazards, especially when frequent entry and exit of the tailwater pipe is required. In addition, with the introduction of special lifting equipment, although the process of entering the tailwater pipe has been improved to a certain extent, since there is no lifting point in the tailwater pipe, the fixing of the lifting equipment still needs to be carried out outside the tailwater gate, which increases the complexity and danger of the entry process.

[0003] Especially in the narrow tailwater gate area, the entry of personnel and equipment becomes more difficult, requiring workers to bear great psychological and physical pressure. In addition, traditional lifting equipment and stairs lack flexibility and convenience and cannot meet the needs of different work scenarios. Summary of the invention

[0004] In view of the above problems existing in the prior art, the present invention is proposed.

[0005] Therefore, the problem to be solved by the present invention is that the existing lifting equipment is complex to operate, has low safety and low efficiency during the maintenance of the tailwater pipe of a hydroelectric generator set.

[0006] To solve the above technical problems, the present invention provides the following technical solutions: a safety auxiliary staircase, comprising a ladder frame, including uprights, handrails, and support tubes, wherein the handrails are arranged on two uprights, and the support tube is arranged at the lower end of the ladder frame; an installation assembly, comprising a connecting rod and a mounting block, one end of the connecting rod is hinged to the upper end of the ladder frame, one end of the mounting block is slidably matched with the connecting rod, and the other end is connected to the bolt hole on the wall of the tailwater gate.

[0007] As a preferred solution of the safety auxiliary staircase described in the present invention, wherein: four fixing rings are arranged on the upright pole; sleeves and springs are arranged on the handrail, the sleeves are arranged at both ends of the handrail and are sleeved on the upright pole, the springs are sleeved on the upright pole and are arranged between the sleeves and the end faces of the fixing rings.

[0008] As a preferred solution of the safety auxiliary staircase of the present invention, wherein: four fixing pins are arranged on the vertical rod; and a straight groove is arranged on the sleeve, and the straight groove matches the fixing pin.

[0009] As a preferred solution of the safety auxiliary staircase described in the present invention, the mounting block includes a shell, a locking member, a trigger member, a bolt, and an unlocking member, the locking member and the trigger member are both arranged in the shell, the bolt passes through the side wall of the shell, and the unlocking member is arranged on the side of the mounting block.

[0010] As a preferred solution of the safety auxiliary staircase described in the present invention, the shell is provided with a sleeve, a first column groove, a second column groove, a lower groove, a gear groove, an inner tooth groove, a third column groove, a long groove, a square groove, and a through groove. The sleeve is arranged above the shell and slidably cooperates with the connecting rod. The first column groove is arranged in the middle of the shell, and the second column groove is arranged on the side wall of the first column groove. The gear groove is connected to the first column groove, and the upper end of the gear groove is connected to the inner side of the sleeve. The inner tooth groove is arranged on the side wall of the first column groove. The third column groove is connected to the first column groove and passes through the side wall of the sleeve. The lower groove is arranged below the second column groove and is connected to the second column groove. The upper end of the long groove is connected to the lower groove, and the lower end is connected to the square groove. The through groove is connected to the side wall of the square groove and passes through the side wall of the shell.

[0011] As a preferred solution of the safety auxiliary staircase described in the present invention, wherein: the locking member includes a rack, a rotating member, and a locking column, the rack is arranged below the connecting rod, and the locking column is arranged in the rotating member; the rotating member includes a rotating cylinder, a fixed rod, a gear, and a sliding sleeve, the rotating cylinder is rotationally matched with the first column groove, the gear is rotationally matched with the gear groove and meshes with the rack, the rotating cylinder and the gear are connected through the fixed rod, and the sliding sleeve is sleeved on the outside of the rotating cylinder and slidingly matched with the second column groove.

[0012] As a preferred solution of the safety auxiliary staircase described in the present invention, wherein: the side wall of the rotating drum is provided with a straight groove, and a notch is provided on the side wall at one end; the locking column is provided with a spiral groove, a clamping groove, and a tooth block, the spiral groove is provided on the side wall of the locking column, the clamping groove is provided on the end face of the locking column, and the tooth block is slidably matched with the clamping groove; the tooth block is provided with a protrusion and a second spring, the protrusion is provided above the tooth block, and the second spring is provided between the tooth block and the end face of the clamping groove; the inner wall of the sliding sleeve is provided with a sliding block, and the sliding block is slidably matched with the spiral groove and the straight groove.

[0013] As a preferred solution of the safety auxiliary staircase described in the present invention, wherein: the trigger member is slidably matched with the long groove, the trigger member is provided with a half ring and a wedge block, the half ring is arranged above the trigger member and slidably matched with the lower groove, the wedge block is arranged at the lower end of the trigger member and slidably matched with the long groove.

[0014] As a preferred solution of the safety auxiliary staircase described in the present invention, wherein: the bolt is slidably matched with the through groove, the bolt is provided with a block, the block is rotationally matched with the bolt and slidably matched with the square groove.

[0015] As a preferred solution of the safety auxiliary staircase described in the present invention, wherein: the unlocking piece is rotatably matched with the third column groove, and is provided with a connecting column and a disengaging disk, the connecting column is arranged on the end face of the unlocking piece, and the disengaging disk is arranged at one end of the connecting column, and is fitted with the end face of the locking column; the end face of the disengaging disk is provided with an inclined groove, and the inclined groove is slidably matched with the protrusion.

[0016] The beneficial effects of the present invention are as follows: the present invention realizes the rapid fixing of the stairs by utilizing the original screw hole design on the tailwater gate. The handrails on both sides of the stairs adopt a retractable design, which saves storage space, is easy to carry, and enhances practicality. The installation assembly enables the position of the installation connecting rod to be fixed when the bolt is connected to the bolt hole on the tailwater gate, further simplifies the operation, and improves the installation efficiency and stability. The stairs are made of stainless steel to ensure the firmness and durability of the structure, and are suitable for use in different environments. The auxiliary stairs are not only simple in structure, easy to install, stable and reliable, but also can significantly reduce the psychological pressure and physical burden of operators, and improve the safety and efficiency of maintenance work. The overall design takes into account both practicality and ease of use, and is particularly suitable for the inspection and maintenance of the tailwater pipe of a vertical turbine, effectively solving many problems existing in traditional methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. Among them:

[0018] Figure 1 Scene diagram of the safety auxiliary stairs.

[0019] Figure 2 This is the structural diagram of the safety auxiliary staircase.

[0020] Figure 3 Structural drawing of the installation components for the safety auxiliary stairs.

[0021] Figure 4 Exploded view of the installation components for the safety auxiliary stairs.

[0022] Figure 5 Exploded view of the rotating parts of the safety auxiliary stairs.

[0023] Figure 6 Sectional view of the installation components for the safety auxiliary stairs. DETAILED DESCRIPTION

[0024] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings.

[0025] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0026] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor is it an embodiment that is mutually exclusive with other embodiments, either individually or selectively.

[0027] Example 1

[0028] Reference Figure 1 and Figure 2 , which is the first embodiment of the present invention, provides a safety auxiliary staircase, which includes a ladder frame 100 and an installation assembly 200.

[0029] Specifically, the ladder frame 100 includes a vertical pole 101, a handrail 102, and a support pipe 103. The handrail 102 is arranged on two vertical poles 101, and the support pipe 103 is arranged at the lower end of the ladder frame 100. The inner wall of the tailwater pipe is a conical pipe. When working, the function of the support pipe 103 is to prevent the stairs from shaking.

[0030] The mounting assembly 200 includes a connecting rod 201 and a mounting block 202. One end of the connecting rod 201 is hinged to the upper end of the ladder frame 100. One end of the mounting block 202 is slidably matched with the connecting rod 201, and the other end is connected to the bolt hole on the wall of the tailgate.

[0031] Two connecting rods 201 are rotatably sleeved on the crossbar at the upper end of the ladder frame 100 , and the two connecting rods 201 are detachably connected to the screw holes on the wall surface of the tailwater gate through mounting blocks 202 .

[0032] Specifically, four fixing rings 101a are provided on the vertical pole 101; sleeves 102a and springs 102b are provided on the handrail 102. The sleeves 102a are provided at both ends of the handrail 102 and are sleeved on the vertical pole 101. The spring 102b is sleeved on the vertical pole 101 and is provided between the sleeves 102a and the end faces of the fixing rings 101a.

[0033] Specifically, four fixing pins 101b are provided on the vertical pole 101; a straight groove 102c is provided on the sleeve 102a, and the straight groove 102c matches the fixing pin 101b;

[0034] The slot, spring 102b and fixing pin 101b realize manual rotation positioning of sleeve 102a. Sleeve 102a is welded to handrail 102 through elbow, so that handrail 102 can be manually opened when using stairs, and handrail 102 can be manually folded after work, saving storage space. It is worth mentioning that in order to completely fold the handrails 102 on both sides after work, the two sides are specially designed to be asymmetrical. Specifically: the sleeve 102a on one side is directly welded to the bent pipe, and the bent pipe is welded to the handrail; while the sleeve 102a on the other side is first welded to the straight steel pipe, and the straight steel pipe is then welded to the bent pipe, and the bent pipe is then welded to the handrail; this avoids the interference problem after the handrails on both sides are folded. In this way, the handrail can be completely retracted and released.

[0035] Example 2

[0036] Reference Figure 1 to Figure 6 , which is the second embodiment of the present invention, and this embodiment is based on the previous embodiment.

[0037] Specifically, the mounting block 202 includes a housing 203, a locking member 204, a trigger member 205, a bolt 202a, and an unlocking member 207. The locking member 204 and the trigger member 205 are both disposed in the housing 203. The bolt 202a penetrates the side wall of the housing 203. The unlocking member 207 is disposed on the side of the mounting block 202.

[0038] The locking piece 204 locks the position of the mounting block 202 on the connecting rod 201. The mounting block 202 can slide before being locked on the connecting rod 201, so as to adapt to tailwater gates of different thicknesses. The bolt 202a connects the mounting block 202 with the tailwater gate. When the bolt 202a is fixed, the triggering piece 205 synchronously drives the locking piece 204 to complete the locking of the position of the mounting block 202 to prevent the stairs from being unstable when people use the stairs. The unlocking piece 207 unlocks the locking piece 204 when the stairs are disassembled.

[0039] Specifically, the housing 203 is provided with a sleeve 203a, a first column groove 203b, a second column groove 203c, a lower groove 203d, a gear groove 203e, an inner tooth groove 203f, a third column groove 203g, a long groove 203h, a square groove 203i, and a through groove 203j. The sleeve 203a is provided above the housing 203 and is slidably matched with the connecting rod 201. The first column groove 203b is provided in the middle of the housing 203. The second column groove 203c is provided on the side wall of the first column groove 203b. The gear groove 203e is connected to the first column groove 203e. The first column groove 203b is connected to the second column groove 203c, the gear groove 203e is connected to the inner side of the sleeve 203a at the upper end, the inner tooth groove 203f is arranged on the side wall of the first column groove 203b, the third column groove 203g is connected to the first column groove 203b and passes through the side wall of the sleeve 203a, the lower groove 203d is arranged below the second column groove 203c and is connected to the second column groove 203c, the upper end of the long groove 203h is connected to the lower groove 203d, and the lower end is connected to the square groove 203i, and the through groove 203j is connected to the side wall of the square groove 203i and passes through the side wall of the housing 203;

[0040] It is worth noting that the first column groove 203b, the second column groove 203c, the gear groove 203e, the inner tooth groove 203f, and the third column groove 203g are all coaxially arranged, and a tooth block is arranged on the side wall of the inner tooth groove 203f.

[0041] Specifically, the locking member 204 includes a rack 204a, a rotating member 206, and a locking column 204b. The rack 204a is arranged below the connecting rod 201, and the locking column 204b is arranged in the rotating member 206; the rotating member 206 includes a rotating cylinder 206a, a fixed rod 206b, a gear 206d, and a sliding sleeve 206e. The rotating cylinder 206a is rotationally matched with the first column groove 203b, the gear 206d is rotationally matched with the gear groove 203e, and meshes with the rack 204a. The rotating cylinder 206a and the gear 206d are connected through the fixed rod 206b, and the sliding sleeve 206e is sleeved on the outer side of the rotating cylinder 206a and slides with the second column groove 203c.

[0042] The rack 204a cooperates with the gear 206d. When the mounting block 202 moves on the connecting rod 201, the rack 204a will drive the gear 206d to rotate. The mounting block 202 can be locked on the connecting rod 201 by simply rotating the fixed gear 204a. It is worth noting that the end face of the locking column 204b is flush with the end face of the rotating drum 206a.

[0043] Specifically, the side wall of the rotating cylinder 206a is provided with a straight groove 206f, and a notch 206c is provided on the side wall at one end; the locking column 204b is provided with a spiral groove 204c, a clamping groove 204d, and a tooth block 204e, the spiral groove 204c is provided on the side wall of the locking column 204b, the clamping groove 204d is provided on the end face of the locking column 204b, and the tooth block 204e is slidably matched with the clamping groove 204d; the tooth block 204e is provided with a protrusion 204f and a second spring 204g, the protrusion 204f is provided above the tooth block 204e, and the second spring 204g is provided between the tooth block 204e and the end face of the clamping groove 204d; the inner wall of the sliding sleeve 206e is provided with a slider 206i, and the slider 206i is slidably matched with the spiral groove 204c and the straight groove 206f;

[0044] In the initial state, the notch 206c is offset from the slot 204d, and the tooth block 206h is blocked by the inner wall of the rotating cylinder 206a, so that the second spring 206g is in a compressed state, and the tooth block 206h is completely located in the slot 204d. It is worth noting that a spring (not shown in the figure) should be provided between the sliding sleeve 206e and the rotating cylinder 206a to ensure that in the initial state, the slider 206i is located at one end of the spiral groove 204c and the straight groove 206f. At this time, the slot 204d is offset from the block 206h. It is worth noting that the size of the notch 206c matches the width of the slot 204d, and the outer side of the tooth block 204e can engage with the inner wall tooth block of the inner tooth groove 203f.

[0045] Specifically, the trigger member 205 is slidably matched with the long groove 203h, and the trigger member 205 is provided with a semi-ring 205a and a wedge block 205b. The semi-ring 205a is arranged above the trigger member 205 and is slidably matched with the lower groove 203d, and the wedge block 205b is arranged at the lower end of the trigger member 205 and is slidably matched with the long groove 203h; the side wall of the semi-ring 205a is provided with an inclined surface 205c;

[0046] It is worth noting that a spring (not shown in the figure) can be arranged between the trigger member 205 and the long groove 203h. In the initial state, the wedge block 205b is located in the square groove 203j, and the half ring 205a is located in the square groove 203d. At this time, the upper end of the inclined surface 205c is in contact with the bottom of the ring 206e.

[0047] Specifically, the bolt 202a is slidably matched with the through slot 203j, and the bolt 202a is provided with a block 202b, which is rotationally matched with the bolt 202a and slidably matched with the square slot 203i;

[0048] In the initial state, one end of the bolt 202a does not extend out of the through slot 203j. At this time, the block 202b contacts the inclined surface of the wedge block 205b. When the bolt 202a is connected to the bolt hole on the tailgate, the block 202b moves in the square slot 203d, thereby squeezing the wedge block 205b, so that the trigger member 205 moves upward, and the inclined surface 205c further squeezes the sliding sleeve 206e. At this time, since the positions of the mounting block 202 and the connecting rod 201 are fixed, The rotating cylinder 206a no longer rotates, so that the sleeve 206e only moves axially, and under the action of the slider 206i and the spiral groove 204c and the straight groove 206f, the locking column 204b rotates. When the slot 204d rotates to coincide with the notch 206c, under the action of the second spring 204g, the tooth block 204e moves into the inner tooth groove 203f and meshes with the tooth block on the side wall of the inner tooth groove 203f, thereby completing the locking of the gear 206d.

[0049] Specifically, the unlocking member 207 is rotatably matched with the third column groove 203g, and is provided with a connecting column 207a and a disengaging disk 207b. The connecting column 207a is provided on the end surface of the unlocking member 207, and the disengaging disk 207b is provided at one end of the connecting column 207a, and is in contact with the end surface of the locking column 204b; the end surface of the disengaging disk 207b is provided with an oblique groove 207c, and the oblique groove 207c is slidably matched with the protrusion 204f;

[0050] In the initial state, the protrusion 204f is located at the end of the inclined slot 207c away from the axis. When the gear 206d rotates, the disengagement plate 207b will rotate with it. When locked, the protrusion 204f moves to the end of the inclined slot close to the axis. When unlocking is required, it is only necessary to rotate the unlocking member 207 so that the protrusion 204f moves back to the end of the inclined slot 207c away from the axis. At this time, the tooth block 204e is reset, and the locking member 206 can be unlocked. Then, the bolt 202a is rotated to complete the disassembly of the stairs.

[0051] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A safety auxiliary staircase, characterized in that: include, A ladder frame (100) comprises a vertical pole (101), a handrail (102), and a support tube (103), wherein the handrail (102) is arranged on two vertical poles (101), and the support tube (103) is arranged at the lower end of the ladder frame (100); The mounting assembly (200) comprises a connecting rod (201) and a mounting block (202), wherein one end of the connecting rod (201) is hinged to the upper end of the ladder frame (100), one end of the mounting block (202) is slidably matched with the connecting rod (201), and the other end is connected to a bolt hole on the wall of the tailgate.

2. The safety auxiliary staircase according to claim 1, characterized in that: The vertical pole (101) is provided with four fixing rings (101a); The handrail (102) is provided with a sleeve (102a) and a spring (102b); the sleeve (102a) is provided at both ends of the handrail (102) and sleeved on the vertical pole (101); the spring (102b) is sleeved on the vertical pole (101) and provided between the sleeve (102a) and the end surface of the fixing ring (101a).

3. The safety auxiliary staircase according to claim 2, characterized in that: The vertical rod (101) is provided with four fixing pins (101b); The sleeve (102a) is provided with a straight groove (102c), and the straight groove (102c) matches the fixing pin (101b).

4. The safety auxiliary staircase according to claim 3, characterized in that: The mounting block (202) comprises a housing (203), a locking member (204), a trigger member (205), a bolt (202a), and an unlocking member (207); the locking member (204) and the trigger member (205) are both arranged in the housing (203); the bolt (202a) passes through a side wall of the housing (203); and the unlocking member (207) is arranged on a side surface of the mounting block (202).

5. The safety auxiliary staircase according to claim 4, characterized in that: The housing (203) is provided with a sleeve (203a), a first column groove (203b), a second column groove (203c), a lower groove (203d), a gear groove (203e), an inner tooth groove (203f), a third column groove (203g), a long groove (203h), a square groove (203i), and a through groove (203j); the sleeve (203a) is arranged above the housing (203) and is slidably matched with the connecting rod (201); the first column groove (203b) is arranged in the middle of the housing (203); the second column groove (203c) is arranged on the side wall of the first column groove (203b); the gear groove (203e) and the first column groove (203b) are connected to each other. The gear groove (203e) is connected to the inner side of the sleeve (203a), the inner tooth groove (203f) is arranged on the side wall of the first column groove (203b), the third column groove (203g) is connected to the first column groove (203b) and passes through the side wall of the sleeve (203a), the lower groove (203d) is arranged below the second column groove (203c) and is connected to the second column groove (203c), the upper end of the long groove (203h) is connected to the lower groove (203d), and the lower end is connected to the square groove (203i), and the through groove (203j) is connected to the side wall of the square groove (203i) and passes through the side wall of the shell (203).

6. The safety auxiliary staircase according to claim 5, characterized in that: The locking member (204) comprises a rack (204a), a rotating member (206), and a locking column (204b), wherein the rack (204a) is arranged below the connecting rod (201), and the locking column (204b) is arranged inside the rotating member (206); The rotating member (206) includes a rotating cylinder (206a), a fixed rod (206b), a gear (206d), and a sliding sleeve (206e). The rotating cylinder (206a) is rotationally matched with the first column groove (203b), the gear (206d) is rotationally matched with the gear groove (203e), and meshes with the rack (204a). The rotating cylinder (206a) and the gear (206d) are connected through the fixed rod (206b), and the sliding sleeve (206e) is sleeved on the outer side of the rotating cylinder (206a) and is slidingly matched with the second column groove (203c).

7. The safety auxiliary staircase according to claim 6, characterized in that: The side wall of the rotating drum (206a) is provided with a straight groove (206f), and one end of the side wall is provided with a notch (206c); The locking column (204b) is provided with a spiral groove (204c), a clamping groove (204d), and a tooth block (204e); the spiral groove (204c) is provided on the side wall of the locking column (204b); the clamping groove (204d) is provided on the end surface of the locking column (204b); and the tooth block (204e) is slidably matched with the clamping groove (204d); The tooth block (204e) is provided with a protrusion (204f) and a second spring (204g); the protrusion (204f) is provided above the tooth block (204e); and the second spring (204g) is provided between the tooth block (204e) and an end surface of the clamping groove (204d); The inner wall of the sliding sleeve (206e) is provided with a sliding block (206i), and the sliding block (206i) is slidably matched with the spiral groove (204c) and the straight groove (206f).

8. The safety auxiliary staircase according to claim 7, characterized in that: The trigger member (205) is slidably matched with the long groove (203h), and the trigger member (205) is provided with a half ring (205a) and a wedge block (205b). The half ring (205a) is arranged above the trigger member (205) and is slidably matched with the lower groove (203d). The wedge block (205b) is arranged at the lower end of the trigger member (205) and is slidably matched with the long groove (203h). The side wall of the semi-ring (205a) is provided with an inclined surface (205c).

9. The safety auxiliary staircase according to claim 8, characterized in that: The bolt (202a) is slidably matched with the through slot (203j), and the bolt (202a) is provided with a block (202b). The block (202b) is rotationally matched with the bolt (202a) and slidably matched with the square slot (203i).

10. The safety auxiliary staircase according to claim 9, characterized in that: The unlocking member (207) is rotatably matched with the third column groove (203g), and is provided with a connecting column (207a) and a disengaging disk (207b), wherein the connecting column (207a) is arranged on the end surface of the unlocking member (207), and the disengaging disk (207b) is arranged on one end of the connecting column (207a) and is in contact with the end surface of the locking column (204b); The end surface of the disengagement disk (207b) is provided with an inclined groove (207c), and the inclined groove (207c) is slidably matched with the protrusion (204f).

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