CN220660232U - Aluminum plate burr treatment device - Google Patents

Abstract

An aluminum plate burr treatment device includes: the polishing device comprises a bottom frame, a polishing assembly and a turnover assembly; the overturning assembly is fixedly arranged in the middle of the upper surface of the bottom frame; the polishing heads of the polishing assembly are inwards placed on two sides of the overturning assembly and are respectively and fixedly installed on the upper surface of the bottom frame. The turnover mechanism is adopted to realize the deflection of the aluminum plate, so that all machining actions can be completed by one-time clamping, and the burr treatment efficiency is improved. The chuck is used as a flexible clamp, so that the flexible clamp can be suitable for aluminum plates with various sizes, and the cost of the tooling clamp is reduced; the chuck can rotate around the axis, the aluminum plate can realize multi-degree-of-freedom posture adjustment on the device, and meanwhile, the device provides reliable connection and ensures operation safety; the universal structural design is adopted, the operation is simple, and the maintenance is convenient.

Description

Aluminum plate burr treatment device

Technical Field

The utility model relates to the technical field of aluminum plate processing, in particular to an aluminum plate burr treatment device.

Background

Because aluminum plate self material characteristic, aluminum plate is after processing, can not avoid burr and overlap, in actual production process, burr and overlap not only can influence normal assembly and use, still can have very big risk to workman's personal safety. CN202223164645.8 discloses an aluminum plate burring processing apparatus is through setting up clear side mechanism, and the hydraulic stem drives the frame of polishing to the inboard side and moves, can be according to different sizes, and nimble adjustment polishes the frame position, makes the emery wheel of polishing and aluminum plate lateral wall contact, and servo motor drive emery wheel polishes aluminum plate lateral wall to realized the technological effect to aluminum plate lateral wall burr high-efficient removal. But the device has larger volume, relatively complex structure and inconvenient operation

Disclosure of Invention

In order to solve the problems, the utility model provides a technical scheme that the aluminum plate burr treatment device comprises: the polishing device comprises a bottom frame, a polishing assembly and a turnover assembly; the overturning assembly is fixedly arranged on the upper end face of the bottom frame and is used for placing the aluminum plate and driving the aluminum plate to overturn; the polishing assembly is provided with two polishing assemblies, and the polishing assemblies are fixedly arranged on the upper end face of the bottom frame and symmetrically located on the left side and the right side of the overturning assembly, and are used for processing burrs of the aluminum plate.

Further, the grinding assembly includes: the device comprises an adjusting hand wheel, a lifting screw, a frame, a grinding head fixing seat, a bearing, a grinding head motor, a guide rail, a bottom plate, a pressing block, a grinding head, a screw seat, a traversing screw and a traversing screw nut; the guide rails are arranged in two and are respectively arranged on the front side and the rear side of the upper surface of the bottom plate in parallel, and sliding blocks are arranged on the guide rails in a sliding manner; the pressing blocks are arranged at the left end and the right end of the guide rail in a group-by-group mode and fixedly connected with the bottom plate; the front end and the rear end of the bottom of the frame are fixedly arranged on the sliding block; the transverse moving screw is horizontally arranged on the upper surface of the bottom plate through the screw seat and is parallel to the guide rail, the transverse moving screw nut is slidably arranged on the transverse moving screw, meanwhile, the transverse moving screw nut is fixedly connected with the lower surface of the frame, and the outward end of the transverse moving screw is coaxially and fixedly connected with an adjusting hand wheel;

the lifting screw rod penetrates through the upper end plate of the frame and is vertically and rotatably arranged on the upper end plate, the top end of the lifting screw rod is fixedly connected with an adjusting hand wheel coaxially, and the bottom end of the lifting screw rod is rotatably connected with the upper part of the grinding head fixing seat through a bearing; the polishing head is arranged on the polishing head fixing seat and is coaxially and fixedly connected with the output end of the polishing head motor, and the polishing head is parallel to the bottom plate and points to the inner side; the grinding head motor is arranged on the grinding head fixing seat.

Further, the overturning assembly comprises an overturning plate, a chuck, a slewing bearing, a limiting plate, an overturning base, a ratchet assembly, an overturning hand wheel, a swinging rod, a rotating shaft, a transmission shaft, a mounting seat, a connecting rod mounting seat, a rotating hand wheel and a transmission assembly; the left end and the right end of the turnover plate are respectively provided with a turnover rotating shaft, four corners of the turnover base are respectively fixedly provided with a boss, the top end of each boss is provided with a rotating shaft groove corresponding to the turnover rotating shaft, and the turnover rotating shafts intermittently rotate in the rotating shaft grooves; the two limiting plates are respectively arranged at the left end and the right end of the overturning base, the two limiting plates are fixedly connected into a whole through a connecting rod, and the connecting rod is horizontally and slidably arranged on the overturning base through a connecting rod mounting seat; the two ends of each limiting plate are fixedly provided with an L-shaped rod, the top cross rod of each L-shaped rod is horizontally and slidably arranged at the top end of the boss, when the turnover rotating shaft at one side is positioned in the rotating shaft groove, the top cross rod of each L-shaped rod at one side slides inwards to seal the rotating shaft groove at the side, so that the turnover rotating shaft at one side can only rotate without displacement, the limiting plate at the other side slides outwards, and the rotating shaft groove at the side is not sealed by the top slide rod of the L-shaped rod;

the mounting seats are respectively and fixedly arranged in the middle positions of the front side and the rear side of the overturning base, and the transmission shafts are rotatably arranged on the mounting seats; the ratchet wheel assembly is arranged on the overturning base, one end of a wheel shaft of the ratchet wheel assembly is fixedly connected with one end of the transmission shaft, and the other end of the wheel shaft of the ratchet wheel assembly is coaxially and fixedly provided with an overturning hand wheel;

the rotating shaft is parallel to the transmission shaft and is rotatably arranged in the middle of the turnover plate; the swing rods are divided into two groups, each group is composed of two swing rods, and one end point of one swing rod is in rotary connection with one end point of the other swing rod; two groups of swing rods are symmetrically arranged, one end of each group of swing rods is rotatably arranged at one end of a rotating shaft, and the other end of each group of swing rods is rotatably arranged at one end of a transmission shaft;

the chuck is rotatably arranged on the turnover plate through a slewing bearing; the rotary hand wheel is rotatably arranged on the overturning plate, the transmission assembly is arranged on the overturning plate, the input end of the transmission assembly is driven by the rotary hand wheel, the output end of the transmission assembly drives the chuck to rotate, and the aluminum plate is arranged on the chuck when burrs are processed.

Further, the ratchet assembly further comprises: the device comprises a bracket, a knob, a ratchet wheel, a limit column, a spring and a spring cover; the ratchet wheel is coaxially and fixedly connected with the wheel shaft, and the wheel shaft is rotatably arranged on the bracket; the ratchet wheel is rotatably arranged on the bracket through a ratchet wheel shaft and positioned at one side of the ratchet wheel, two pawls are symmetrically arranged on the ratchet wheel up and down, and the two pawls are alternately inserted into gear tooth gaps of the ratchet wheel and used for unidirectional forward and reverse rotation of the ratchet wheel; the knob is coaxially and fixedly connected with the outer end of the pawl wheel shaft and is rotatably arranged at the outer side of the bracket; the limiting column is slidably arranged in the spring cover through the spring, the spring cover is communicated with the bracket, and the limiting column props against the upper side or the lower side of the tail end of the ratchet wheel when extending into the bracket, so that one pawl is inserted into a gear tooth gap of the ratchet wheel, and unidirectional rotation of the ratchet wheel is ensured.

Due to the adoption of the technical scheme, the utility model has the following advantages:

1. the turnover mechanism is adopted to realize the deflection of the aluminum plate, and all machining actions can be completed by one-time clamping.

2. The chuck is used as a flexible clamp, and the flexible clamp is applicable to aluminum plates with various sizes.

3. The universal structural design is adopted, the operation is simple, and the maintenance is convenient.

Drawings

FIG. 1 is an isometric view of the overall structure of the present utility model.

Fig. 2 is a schematic front view of a sanding assembly in accordance with the present utility model.

Fig. 3 is a rear schematic view of the sanding assembly of the present utility model.

Fig. 4 is a schematic front view of the flip assembly of the present utility model.

Fig. 5 is a rear side schematic view of the flip assembly of the present utility model.

Fig. 6-9 are schematic axial views of a ratchet assembly according to the present utility model.

Fig. 10 is a schematic axial side view of the roll-over panel of the present utility model.

Fig. 11 is a side view of the utility model on the roll-over panel.

Fig. 12 is a schematic axial side view of the flip base of the present utility model.

Reference numerals: 1-a bottom frame; 2-a grinding assembly; 3-a flip assembly; 201-adjusting a hand wheel; 202-lifting a screw rod; 203-a frame; 204, grinding head fixing seats; 205-bearings; 206-a grinding head motor; 207-a guide rail; 208-floor; 209-briquetting; 210-grinding head; 211-a screw seat; 212-traversing the lead screw; 213-traversing the lead screw nut; 301-a flipping panel; 302-a chuck; 303-a slewing bearing; 304-limiting plates; 305-overturning the base; 306-a ratchet assembly; 307-overturning the hand wheel; 308-swinging rod; 309-a spindle; 310-a transmission shaft; 311-mounting seats; 312-connecting rod; 313-a connecting rod mount; 314-rotating the hand wheel; 315-a transmission assembly; 3061-scaffold; 3062-axle; 3063-knob; 3064-ratchet wheel; 3065—detent wheel; 3066-a limit column; 3067-spring; 3068-spring cover;

Detailed Description

The technical scheme of the utility model is further specifically described below through examples and with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present utility model, but the present utility model may be embodied in many other forms than described herein, and persons skilled in the art will be able to make similar modifications without departing from the spirit of the utility model, so that the utility model is not limited to the specific embodiments disclosed below.

In the description of the present utility model, it should be noted that, directions or positional relationships indicated by terms such as "upper", "lower", "front", "rear", "left", "right", etc., are based on directions or positional relationships shown in the drawings, or directions or positional relationships in which the inventive product is conventionally put in use, are merely for convenience of describing the present utility model and simplifying the description, and are not indicative or implying that the apparatus or element to be referred to must have a specific direction, be configured and operated in a specific direction, and thus should not be construed as limiting the present utility model.

Examples

As shown in fig. 1, the aluminum plate burr treatment device comprises a bottom frame 1, a polishing assembly 2 and a turnover assembly 3; the overturning assembly 3 is fixedly arranged on the upper end face of the bottom frame 1 and is used for placing an aluminum plate and driving the aluminum plate to overturn; the two polishing assemblies 2 are fixedly arranged on the upper end face of the bottom frame 1 and symmetrically positioned on the left side and the right side of the overturning assembly 3, and are used for processing burrs of the aluminum plate;

as shown in fig. 2 to 3, the grinding assembly 2 includes an adjusting hand wheel 201, a lifting screw 202, a frame 203, a grinding head fixing base 204, a bearing 205, a grinding head motor 206, a guide rail 207, a bottom plate 208, a pressing block 209, a grinding head 210, a screw seat 211, a traversing screw 212, and a traversing screw nut 213; the guide rail 207 is provided with two guide rails which are respectively arranged on the front side and the rear side of the upper surface of the bottom plate 208 in parallel, and the guide rail 207 is provided with a sliding block in a sliding way; the pressing blocks 209 are respectively arranged at the left end and the right end of the guide rail 207 in a group-by-group manner and are fixedly connected with the bottom plate 208; the front and rear ends of the bottom of the frame 203 are fixedly arranged on the sliding blocks; the transverse moving screw 212 is horizontally arranged on the upper surface of the bottom plate 208 through a screw seat 211 and is parallel to the guide rail 207, a transverse moving screw nut 213 is slidably arranged on the transverse moving screw 212, meanwhile, the transverse moving screw nut 213 is fixedly connected with the lower surface of the frame 203, and the outward end of the transverse moving screw 212 is fixedly connected with an adjusting hand wheel 201 coaxially;

the lifting screw 202 penetrates through the upper end plate of the frame 203 and is vertically and rotatably arranged on the upper end plate, the top end of the lifting screw is fixedly connected with an adjusting hand wheel 201 coaxially, and the bottom end of the lifting screw is rotatably connected with the upper part of the grinding head fixing seat 204 through a bearing 205; the grinding head 210 is mounted on the grinding head fixing seat 204 and is coaxially and fixedly connected with the output end of the grinding head motor 206, and the grinding head 210 is parallel to the bottom plate 208 and points to the inner side; the grinding head motor 206 is mounted on the grinding head fixing seat 204; the polishing head 210 of the polishing assembly 2 on the left side is a cylindrical polishing head, and the polishing head 210 of the polishing assembly 2 on the right side is a cake-shaped polishing head;

as shown in fig. 4-5 and 10-12, the turnover assembly 3 comprises a turnover plate 301, a chuck 302, a revolving bearing 303, a limiting plate 304, a turnover base 305, a ratchet assembly 306, a turnover hand wheel 307, a swing rod 308, a rotating shaft 309, a transmission shaft 310, a mounting seat 311, a connecting rod 312, a connecting rod mounting seat 313, a rotation hand wheel 314 and a transmission assembly 315; the left end and the right end of the turnover plate 301 are respectively provided with a turnover rotating shaft, four corners of the turnover base 305 are respectively fixedly provided with a boss, the top end of each boss is provided with a rotating shaft groove corresponding to the turnover rotating shaft, and the turnover rotating shafts intermittently rotate in the rotating shaft grooves; the two limiting plates 304 are respectively arranged at the left end and the right end of the overturning base 305, the two limiting plates 304 are fixedly connected into a whole by a connecting rod 312, and the connecting rod 312 is horizontally and slidably arranged on the overturning base 305 through a connecting rod mounting seat 313; an L-shaped rod is fixedly arranged at two ends of each limiting plate 304, a top cross rod of the L-shaped rod is horizontally and slidably arranged at the top end of the boss, when a turnover rotating shaft at one side is positioned in the rotating shaft groove, the top cross rod of the L-shaped rod at one side slides inwards to seal the rotating shaft groove at the side, so that the turnover rotating shaft at one side can only rotate without displacement, and the limiting plates 304 at the other side slide outwards, and the rotating shaft groove at the side is not sealed by the top slide rod of the L-shaped rod; when the turnover plate 301 is at the initial position, the turnover plate 301 is horizontally placed on the turnover base 305, and the turnover rotating shafts on two sides are respectively positioned in the corresponding rotating shaft grooves;

the mounting seats 311 are respectively and fixedly arranged in the middle positions of the front side and the rear side of the overturning base 305, and the transmission shaft 310 is rotatably arranged on the mounting seats 311; the ratchet assembly 306 is mounted on the overturning base 305, one end of a wheel shaft 3062 of the ratchet assembly 306 is fixedly connected with one end of the transmission shaft 310, and the other end is coaxially and fixedly provided with the overturning hand wheel 307;

the rotating shaft 309 is parallel to the transmission shaft 310 and rotatably installed at a middle position of the flipping plate 301; the swing rods 308 are divided into two groups, each group is composed of two swing rods 308, and one end point of one swing rod 308 is in rotary connection with one end point of the other swing rod 308; two groups of swing rods 308 are symmetrically arranged, one end of each group of swing rods 308 is rotatably arranged at one end of a rotating shaft 309, and the other end is rotatably arranged at one end of a transmission shaft 310;

the chuck 302 is rotatably mounted on the inversion plate 301 by a swivel bearing 303; the rotary hand wheel 314 is rotatably mounted on the flipping plate 301; the transmission assembly 315 includes an input gear and an output gear, the input gear is fixedly connected with the rotary hand wheel 314 coaxially, the output gear is fixedly connected with the chuck 302 coaxially, and the input gear and the output gear are both rotatably mounted on the turnover plate 301; when burrs are processed, an aluminum plate is mounted on the chuck 302;

as shown in fig. 6-9, the ratchet assembly 306 further includes: a bracket 3061, a knob 3063, a ratchet 3064, a ratchet wheel 3065, a limit post 3066, a spring 3067, and a spring cover 3068; the ratchet 3064 is fixedly connected with the wheel shaft 3062 coaxially, and the wheel shaft is rotatably arranged on the bracket 3061; the ratchet wheel 3065 is rotatably installed on the bracket 3061 through a ratchet wheel shaft and is located at one side of the ratchet 3064, in this embodiment, two pawls are symmetrically installed at the front end of the ratchet wheel 3065 up and down, and the two pawls are alternately inserted into a gear tooth gap of the ratchet 3064 for unidirectional forward and reverse rotation of the ratchet 3064; the rear end of the detent wheel 3065 consists of two symmetrical conical surfaces; the knob 3063 is coaxially and fixedly connected with the outer end of the pawl wheel shaft, and is rotatably arranged at the outer side of the bracket 3061; the limit post 3066 is slidably mounted in the spring cover 3068 through the spring 3067, the spring cover 3068 is communicated with the bracket 3061, the knob 3063 is twisted, the limit post 3066 is extruded outwards when the pawl wheel 3065 rotates, and when the pawl on the pawl wheel 3065 clamps the lower part or the upper part of the ratchet wheel 3064, the limit post 3066 stretches into the bracket 3061 and abuts against the upper side or the lower side of the tail end of the pawl wheel 3065, so that the ratchet wheel 3064 is guaranteed to rotate unidirectionally;

working steps of the embodiment are as follows:

the first step: an aluminum plate is placed on the chuck 302; pushing the left limiting plate 304 to move inwards, and pushing the right limiting plate 304 to move outwards, so that the left overturning rotating shaft is sealed; the turning knob 3063 drives the pawl wheel 3065 to rotate so that a pawl positioned below can clamp the ratchet 3064, and the overturning plate 301 can only overturn leftwards; the operator rotates the overturning hand wheel 307, and rotates the overturning plate 301 to a vertical state through the swing rod 308, the rotating shaft 309 and the transmission shaft 310 to face the left grinding assembly 2;

and a second step of: turning the two adjusting handwheels 201 of the left grinding assembly 2, adjusting the position of the grinding head 210, starting the grinding head motor 206, and starting grinding; after finishing polishing, turning off the grinding head motor 206;

and a third step of: pushing the limiting plate 304 on the right side to move inwards, and pushing the limiting plate 304 on the left side to move outwards; turning the knob 3063 in the opposite direction, the pawl located above of the two pawls of the pawl wheel 3065 is inserted into the gear tooth gap of the ratchet 3064, so that the flipping plate 301 can only flip to the right; reversely rotating the turning hand wheel 307, the turning plate 301 is rotated to the right and keeps the upright state facing the grinding assembly 2 to the right; meanwhile, the left limiting plate 304 is pushed, the right limiting plate 304 moves outwards, the right overturning rotating shaft is embedded into the rotating shaft groove, and the right limiting plate 304 is pushed to move inwards again to seal the right overturning rotating shaft;

fourth step: turning the two adjusting handwheels 201 of the right grinding assembly 2, adjusting the position of the grinding head 210, starting the grinding head motor 206, and starting grinding; after finishing polishing, turning off the grinding head motor 206;

fifth step: turning the knob 3063, inserting the two pawls of the pawl wheel 3065 below into the gear teeth gap of the ratchet 3064, rotating the turning hand wheel 307 to rotate the turning plate 301, embedding the turning shaft on the left into the shaft groove, horizontally placing the turning plate 301 on the turning base 305, and removing the aluminum plate from the chuck 302;

the burrs of the aluminum plate are processed through the steps.

Claims (4)

1. An aluminum plate burr treatment device, characterized by comprising: the polishing device comprises a bottom frame (1), a polishing assembly (2) and a turnover assembly (3); the overturning assembly (3) is fixedly arranged on the upper end face of the bottom frame (1) and is used for placing an aluminum plate and driving the aluminum plate to overturn; the polishing assemblies (2) are arranged at two sides, are fixedly arranged on the upper end face of the bottom frame (1) and are symmetrically arranged at the left side and the right side of the overturning assembly (3), and are used for processing burrs of the aluminum plate.

2. An aluminium plate burr treatment device according to claim 1, characterized in that the grinding assembly (2) comprises: the device comprises an adjusting hand wheel (201), a lifting screw (202), a frame (203), a grinding head fixing seat (204), a bearing (205), a grinding head motor (206), a guide rail (207), a bottom plate (208), a pressing block (209), a grinding head (210), a screw seat (211), a traversing screw (212) and a traversing screw nut (213); the two guide rails (207) are respectively arranged on the front side and the rear side of the upper surface of the bottom plate (208) in parallel, and the guide rails (207) are provided with sliding blocks in a sliding manner; the pressing blocks (209) are respectively arranged at the left end and the right end of the guide rail (207) in a group-by-group mode and are fixedly connected with the bottom plate (208); the front end and the rear end of the bottom of the frame (203) are fixedly arranged on the sliding block; the transverse moving screw (212) is horizontally arranged on the upper surface of the bottom plate (208) through a screw seat (211) and is parallel to the guide rail (207), the transverse moving screw nut (213) is slidably arranged on the transverse moving screw (212), meanwhile, the transverse moving screw nut (213) is fixedly connected with the lower surface of the frame (203), and the outward end of the transverse moving screw (212) is coaxially and fixedly connected with an adjusting hand wheel (201);

the lifting screw rod (202) penetrates through the upper end plate of the frame (203) and is vertically and rotatably arranged on the upper end plate, the top end of the lifting screw rod is fixedly connected with an adjusting hand wheel (201) coaxially, and the bottom end of the lifting screw rod is rotatably connected with the upper part of the grinding head fixing seat (204) through a bearing (205); the polishing head (210) is arranged on the polishing head fixing seat (204) and is coaxially and fixedly connected with the output end of the polishing head motor (206), and the polishing head (210) is parallel to the bottom plate (208) and points to the inner side; the grinding head motor (206) is arranged on the grinding head fixing seat (204).

3. An aluminum plate burr treatment apparatus according to claim 1, wherein the turning assembly (3) comprises a turning plate (301), a chuck (302), a swivel bearing (303), a limiting plate (304),

The turnover device comprises a turnover base (305), a ratchet assembly (306), a turnover hand wheel (307), a swing rod (308), a rotating shaft (309), a transmission shaft (310), a mounting seat (311), a connecting rod (312), a connecting rod mounting seat (313), a rotation hand wheel (314) and a transmission assembly (315); the left end and the right end of the turnover plate (301) are respectively provided with a turnover rotating shaft, four corners of the turnover base (305) are respectively fixedly provided with a boss, the top end of each boss is provided with a rotating shaft groove corresponding to the turnover rotating shaft, and the turnover rotating shafts intermittently rotate in the rotating shaft grooves; the two limiting plates (304) are respectively arranged at the left end and the right end of the overturning base (305), the two limiting plates (304) are fixedly connected into a whole through a connecting rod (312), and the connecting rod (312) is horizontally and slidably arranged on the overturning base (305) through a connecting rod mounting seat (313); an L-shaped rod is fixedly arranged at two ends of each limiting plate (304), a top cross rod of the L-shaped rod is horizontally and slidably arranged at the top end of the boss, when a turnover rotating shaft at one side is positioned in the rotating shaft groove, the top cross rod of the L-shaped rod at one side slides inwards to seal the rotating shaft groove at the side, so that the turnover rotating shaft can only rotate without displacement, and the limiting plates (304) at the other side slide outwards, and the rotating shaft groove at the side is not sealed by the top slide rod of the L-shaped rod;

the mounting seats (311) are respectively and fixedly arranged in the middle positions of the front side and the rear side of the overturning base (305), and the transmission shafts (310) are rotatably arranged on the mounting seats (311); the ratchet wheel assembly (306) is arranged on the overturning base (305), one end of a wheel shaft (3062) of the ratchet wheel assembly (306) is fixedly connected with one end of the transmission shaft (310), and the overturning hand wheel (307) is coaxially and fixedly arranged at the other end of the transmission shaft;

the rotating shaft (309) is parallel to the transmission shaft (310) and is rotatably arranged in the middle of the turnover plate (301); the swinging rods (308) are divided into two groups, each group is composed of two swinging rods (308), and one end point of one swinging rod (308) is in rotary connection with one end point of the other swinging rod (308); two groups of swing rods (308) are symmetrically arranged, one end of each group of swing rods (308) is rotatably arranged at one end of a rotating shaft (309), and the other end of each group of swing rods is rotatably arranged at one end of a transmission shaft (310);

the chuck (302) is rotatably mounted on the overturning plate (301) through a slewing bearing (303); the rotary hand wheel (314) is rotatably arranged on the overturning plate (301), the transmission assembly (315) is arranged on the overturning plate (301), the input end of the transmission assembly is driven by the rotary hand wheel (314), the output end of the transmission assembly drives the chuck (302) to rotate, and the aluminum plate is arranged on the chuck (302) when burrs are processed.

4. A device for processing burrs on an aluminum plate as claimed in claim 3, characterized in that said ratchet assembly (306) further comprises: a bracket (3061), a knob (3063), a ratchet (3064), a click wheel (3065), a limit post (3066), a spring (3067) and a spring cover (3068); the ratchet wheel (3064) is fixedly connected with the wheel shaft (3062) coaxially, and the wheel shaft is rotatably arranged on the bracket (3061); the pawl wheel (3065) is rotatably arranged on the bracket (3061) through a pawl wheel shaft and is positioned on one side of the ratchet wheel (3064), the pawl wheel (3065) is symmetrically provided with two pawls, and the two pawls are alternately inserted into a gear tooth gap of the ratchet wheel (3064) and used for unidirectional forward and reverse rotation of the ratchet wheel (3064); the knob (3063) is coaxially and fixedly connected with the outer end of the pawl wheel shaft, and is rotatably arranged at the outer side of the bracket (3061); the limiting column (3066) is slidably mounted in the spring cover (3068) through the spring (3067), the spring cover (3068) is communicated with the support (3061), the limiting column (3066) props against the upper side or the lower side of the tail end of the ratchet wheel (3065) when extending into the support (3061), one of the pawls is inserted into a gear tooth gap of the ratchet wheel (3064), and unidirectional rotation of the ratchet wheel (3064) is guaranteed.