Blade grinding mechanism

Abstract

The utility model discloses a blade polishing mechanism which comprises a telescopic arm arranged on a lifting frame and a polishing assembly connected to the tail end of the telescopic arm. The polishing assembly comprises a swing bridge and a swing head which are sequentially connected with the telescopic arm, and the middle of the swing bridge is movably connected with the swing head through a longitudinal fixing shaft. Elastic pieces are arranged at the two ends of the face, connected with the swing bridge, of the swing head respectively, and the other ends of the elastic pieces are connected with the two ends of the swing bridge respectively; the end, connected with the telescopic arm, of the swing bridge is provided with a transversely-arranged driving shaft, and the swing bridge is driven by the driving shaft to swing up and down; the two sides of the driving shaft are connected with driving pieces correspondingly, and the driving pieces are connected with the elastic pieces on the sides where the driving pieces are located and drive the elastic pieces to push the swing head to swing left and right. The polishing mechanism is further provided with an inductor. And through the polishing assembly, the posture of the swing head and the pressure in contact with the blade are adjusted in a self-adaptive mode, and the polishing effect and pressure control are guaranteed.

Description

Technical Field

[0001] The utility model belongs to the field of blade grinding, and in particular relates to a blade grinding mechanism. Background Art

[0002] Blade grinding mechanism refers to a device or system used to grind blades. In industrial production, blades are a common component and are widely used in turbines, fans, water pumps, compressors and other equipment. In order to ensure the processing quality and performance of blades, advanced grinding mechanisms are required for processing. Blade grinding usually includes processes such as rough grinding, fine grinding and polishing. Rough grinding is used to remove the initial wear layer and burrs, fine grinding is used to improve the surface accuracy and finish of the blades, and polishing is to make the blade surface smoother. Blade grinding usually uses CNC grinders or special blade grinders. These equipment have the characteristics of high precision, high stability and high efficiency, and can meet the requirements of blade processing. The process parameters of blade grinding include grinding speed, feed speed, grinding pressure and grinding fluid. Reasonable process parameters can ensure the quality and efficiency of blade processing. Ultimately, the surface quality of the blade after grinding will directly affect the performance of the blade. Therefore, when grinding the blade, the adjustment and pressure control of the grinding equipment are required to be high, that is, the grinding angle and grinding force will affect the effect of blade grinding.

[0003] The Chinese patent application with publication number CN107253123A discloses a double-sided grinding arm device for grinding large ship propellers, which mainly uses double-sided grinding to reduce vibration generated during grinding, but does not solve problems such as grinding pressure control.

[0004] Therefore, there is an urgent need to provide a blade grinding mechanism to solve the problems existing in the prior art. Summary of the invention

[0005] In response to the problems existing in the prior art, the utility model provides a blade grinding mechanism, which can adaptively adjust the grinding posture by controlling the swing bridge and the swing head through a driving part and an elastic part. The driving part utilizes the cylinder to provide power and the characteristics of the elastic part to drive the elastic part to adjust the posture of the swing head and the pressure of contact with the blade, thereby ensuring the grinding effect and pressure control.

[0006] The technical solution of the utility model is achieved in this way:

[0007] A blade grinding mechanism comprises a telescopic arm arranged on a lifting frame and a grinding assembly connected to the end of the telescopic arm;

[0008] The polishing assembly comprises a swing bridge and a swing head which are sequentially connected to the telescopic arm, wherein the middle portion of the swing bridge is movably connected to the swing head via a longitudinal fixed shaft; elastic members are respectively provided at both ends of a side of the swing head connected to the swing bridge, and the other ends of the elastic members are respectively connected to the two ends of the swing bridge;

[0009] One end of the swing bridge connected to the telescopic arm has a transversely arranged driving shaft, and the swing bridge is driven to swing up and down by the driving shaft; driving parts are respectively connected to the two sides of the driving shaft, and the driving parts are respectively connected to the elastic parts on the side, and drive the elastic parts to push the swing head to swing left and right.

[0010] Specifically, the driving member uses a cylinder to provide power, and the driving member is mainly used to apply a driving force to the elastic member, that is, to apply a pre-tightening force by using the characteristics of the elastic member, so that the swing head fits on the blade with just the right force, avoiding excessive pressure on the blade or not closely fitting on the blade, which affects the grinding effect; at the same time, the elastic force of the elastic member can be used to adjust the swing head to swing left and right;

[0011] The elastic member may be a spring;

[0012] The driving shaft is connected to a motor, and the motor drives the driving shaft to rotate, thereby driving the pendulum bridge to swing up and down.

[0013] Preferably, the swing bridge includes a swing arm, a driving member and a driving shaft, the swing arm includes an axis plate provided with an axis hole, and a swinging part and a connecting part connected to both sides of the axis plate, the swinging part is provided with a through hole, and the elastic member is connected to the driving member through the through hole of the swinging part.

[0014] Specifically, the swing part is slightly bent in a direction away from the swing head, so that a space is left between the swing part of the swing bridge and the swing head, so that the swing bridge can adjust the swing head left and right through the elastic member.

[0015] Preferably, the connecting portion is arranged in parallel on both sides of the driving shaft and connected to the swinging portion, one side of the driving member is connected to the driving shaft, and the other side thereof is fixed to the connecting portion.

[0016] Specifically, the connecting part is arranged at the positions of the two wings of the swing bridge, and is mainly used to connect and fix the driving member; the driving member is connected to the driving shaft, and the driving member can swing up and down through the driving shaft. The driving member is fixed on the connecting part at the same time, so that the swing bridge and the driving member swing synchronously, and the driving member provides a pre-tightening force to the elastic member.

[0017] Preferably, the swing head includes a connecting frame movably connected to the swing arm and a rotatable roller arranged on the connecting frame; one side of the connecting frame connected to the swing arm is provided with two upper and lower mounting plates parallel to each other, the axis plate of the swing arm is located between the upper and lower mounting plates, and an axis hole corresponding to the axis plate is provided in the middle of the mounting plate, and the mounting plate is movably connected to the axis plate through the axis hole.

[0018] Specifically, the shaft plate and the mounting plate are movably connected through the shaft hole, so that the shaft plate can be rotated within a limited range between the two mounting plates, thereby cooperating with the driving member and the elastic member to perform left and right adjustment.

[0019] Preferably, the connecting frame is located at one end away from the swing bridge, and two connecting plates are symmetrically provided on both sides thereof, and the roller is located between the two connecting plates; and grinding sheets are distributed on the surface of the roller around its axial direction.

[0020] Specifically, the roller can rotate between the two connecting plates, thereby driving the grinding sheet on its surface to rotate, thereby achieving the effect of grinding the blades.

[0021] Preferably, an upper shell and a lower shell are respectively provided at the upper and lower ends of the drum, and the upper shell and the lower shell are respectively fixedly connected to the connecting frame and the connecting plates at both sides thereof.

[0022] Specifically, the upper shell and the lower shell are mainly used for auxiliary connection, fixing the drum and dust prevention, and other equipment such as sensors can be arranged on the upper and lower shells.

[0023] Preferably, distance measuring wheels are respectively provided on the connection plates on both sides of the connection frame; the distance measuring wheels are coaxially arranged with the roller, and the radius of the distance measuring wheels is adapted to the radius of the roller.

[0024] Specifically, the distance measuring wheel includes a measuring wheel part and a connecting rod part, and the connecting rod part is fixedly connected to the connecting frame;

[0025] The edge of the distance measuring wheel and the grinding sheet can contact the surface of the blade at the same time to determine whether the grinding head is in contact with the blade. The driving member powered by the cylinder drives the elastic member to perform adaptive adjustment, and the preload force is applied in cooperation with the sensor. The distance measuring wheel is mainly used to determine the distance between the grinding head and the blade in cooperation with the sensor. The preload force between the grinding head and the blade can be more accurately adjusted and controlled by the contact between the distance measuring wheel and the blade.

[0026] Preferably, the polishing mechanism is further provided with a sensor; the sensor comprises a distance measuring sensor, an upper stop sensor and a lower stop sensor; the upper shell and the lower shell are respectively provided with a distance measuring sensor, and the lower shell is also provided with a lower stop sensor.

[0027] Specifically, the distance measuring sensor is mainly used to detect the distance between the swing head and the surface of the blade; the upper stop sensor is mainly used to detect the upper edge of the blade to be polished, and the lower stop sensor is mainly used to detect the lower edge of the blade. The upper and lower edges of the blade are detected by the upper stop sensor and the lower stop sensor, thereby achieving complete polishing. At the same time, it is convenient to adjust the position and direction when reaching the polished edge of the blade to continue polishing another area.

[0028] Preferably, a rotatable dustproof plate is provided at one end of the upper shell and the lower shell away from the swing bridge, and a dustproof brush is provided at the end of the dustproof plate; a dust removal channel is also provided on the upper shell and the lower shell; and the dust removal channel is connected to a dust removal device through a pipeline.

[0029] Specifically, the distance measuring sensor is located beside the dust removal passage, away from one end of the outlet thereof;

[0030] The dust plate and the dust brush are mainly used to collect the dust generated by grinding the blades into the upper and lower shells. The dust removal channel is connected with the upper and lower shells, and the dust is discharged through the dust removal channel. The dust removal device can be a dust collector, which is connected with the outlet of the dust removal channel through a pipeline.

[0031] Preferably, the telescopic arm comprises a fixed arm, a first connecting arm and a second connecting arm which are slidably connected in sequence; the second connecting arm is connected to the swing bridge, and the fixed arm is connected to the lifting frame; and the upper stop sensor is arranged on the fixed arm.

[0032] Specifically, a slide rail and a slider may be provided between the fixed arm, the first connecting arm, and the second connecting arm, and the first connecting arm and the second connecting arm may be sleeved in sequence to control the extension and contraction of the first connecting arm and the second connecting arm.

[0033] Compared with the prior art, the utility model achieves the following beneficial effects:

[0034] The utility model provides a blade grinding mechanism, which realizes adaptive floating grinding through the driving part and elastic part between the swing head and the swing bridge, and the posture is adjusted by the sensor; the driving part powered by the cylinder cooperates with the elastic part to provide pre-tightening force, so that the force of the swing head and the blade is appropriate, and it is avoided that the force of the swing head pressing on the blade surface is too large or too small, which affects the grinding effect; the characteristics of the elastic part can be used to make the elastic force applied to the blade surface constant, so as to achieve stable grinding, and at the same time, the elastic part between the swing bridge and the swing head can be used to push the swing head to swing left and right, so as to realize the adaptive floating of the swing head on the blade surface, and the distance between the grinding head and the blade surface and the blade edge can be detected by the sensor, so as to achieve the function of automatic grinding, and at the same time, the grinding effect and pressure control are guaranteed, thereby improving the blade grinding quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1This is one of the structural schematic diagrams of a blade grinding mechanism provided by an embodiment of the utility model;

[0036] Figure 2 This is the second structural schematic diagram of a blade grinding mechanism provided by an embodiment of the utility model;

[0037] Figure 3 The utility model provides a blade grinding mechanism. Figure 2 The enlarged schematic diagram of the middle A part;

[0038] Figure 4 It is a partial structural connection diagram of a blade grinding mechanism provided by an embodiment of the utility model;

[0039] Figure 5 It is a structural schematic diagram of a swing bridge of a blade grinding mechanism provided by an embodiment of the utility model;

[0040] Figure 6 It is a structural schematic diagram of a connecting frame of a blade grinding mechanism provided by an embodiment of the utility model;

[0041] Figure 7 It is a structural schematic diagram of a drum of a blade grinding mechanism provided by an embodiment of the utility model;

[0042] Figure 8 It is a structural schematic diagram of a distance measuring wheel of a blade grinding mechanism provided in an embodiment of the utility model.

[0043] Reference numerals:

[0044] 101, swing bridge; 102, drive shaft; 103, drive member; 104, shaft plate; 105, swing part; 106, connecting part; 107, fixed shaft; 108, motor;

[0045] 201, swing head; 202, elastic member; 203, connecting frame; 204, roller; 205, mounting plate; 206, shaft hole; 207, connecting plate; 208, grinding sheet;

[0046] 301, upper shell; 302, lower shell; 303, distance measuring wheel; 304, measuring wheel; 305, connecting rod; 306, dustproof plate; 307, dustproof brush; 308, dust removal channel; 309, distance measuring sensor; 310, upper stop sensor; 311, lower stop sensor;

[0047] 401, fixed arm; 402, first connecting arm; 403, second connecting arm. DETAILED DESCRIPTION

[0048] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0049] Example

[0050] like Figures 1 to 8 , a blade grinding mechanism, comprising a telescopic arm disposed on a lifting frame and a grinding assembly connected to the end of the telescopic arm;

[0051] The polishing assembly comprises a swing bridge 101 and a swing head 201 which are sequentially connected to the telescopic arm, wherein the middle portion of the swing bridge 101 is movably connected to the swing head 201 via a longitudinal fixed shaft 107; elastic members 202 are respectively provided at both ends of a side of the swing head 201 which is connected to the swing bridge 101, and the other ends of the elastic members 202 are respectively connected to both ends of the swing bridge 101;

[0052] One end of the swing bridge 101 connected to the telescopic arm has a transversely arranged driving shaft 102, and the driving shaft 102 drives the swing bridge 101 to swing up and down; driving parts 103 are respectively connected to the two sides of the driving shaft 102, and the driving parts 103 are respectively connected to the elastic parts 202 on the side, and drive the elastic parts 202 to push the swing head 201 to swing left and right.

[0053] The driving member 103 is powered by a cylinder and is mainly used to apply a driving force to the elastic member 202, that is, to apply a pre-tightening force by utilizing the characteristics of the elastic member 202, so that the swing head 201 is just fitted to the blade, thereby preventing it from being excessively pressed on the blade or not being closely attached to the blade, thereby affecting the grinding effect; at the same time, the elastic force of the elastic member 202 can be used to adjust the swing head 201 to swing left and right;

[0054] The elastic member 202 may be a spring;

[0055] The driving shaft 102 is connected to a motor 108 , and the motor 108 drives the driving shaft 102 to rotate, thereby driving the swing bridge 101 to swing up and down.

[0056] The swing bridge 101 includes a swing arm, a driving member 103 and a driving shaft 102. The swing arm includes an axis plate 104 with an axis hole 206, and a swinging part 105 and a connecting part 106 connected to both sides of the axis plate 104. The swinging part 105 is provided with a through hole, and the elastic member 202 is connected to the driving member 103 through the through hole of the swinging part 105.

[0057] The swinging portion 105 is slightly bent in a direction away from the swinging head 201 , so that a space is left between the swinging portion 105 of the swinging bridge 101 and the swinging head 201 , so that the swinging bridge 101 can adjust the swinging head 201 left and right through the elastic member 202 .

[0058] The connecting portion 106 is disposed in parallel on both sides of the driving shaft 102 and connected to the swinging portion 105 . One side of the driving member 103 is connected to the driving shaft 102 , and the other side thereof is fixed to the connecting portion 106 .

[0059] The connecting part 106 is arranged at the positions of the two wings of the pendulum bridge 101, and is mainly used to connect and fix the driving member 103; the driving member 103 is connected to the driving shaft 102, and the driving member 103 can swing up and down through the driving shaft 102. The driving member 103 is also fixed on the connecting part 106, so that the pendulum bridge 101 and the driving member 103 swing synchronously, and the driving member 103 provides a pre-tightening force to the elastic member 202.

[0060] The swing head 201 includes a connecting frame 203 movably connected to the swing arm and a rotatable roller 204 arranged on the connecting frame 203; one side of the connecting frame 203 connected to the swing arm is provided with two upper and lower parallel mounting plates 205, the shaft plate 104 of the swing arm is located between the upper and lower mounting plates 205, and an shaft hole 206 corresponding to the shaft plate 104 is provided in the middle of the mounting plate 205, and the mounting plate 205 is movably connected to the shaft plate 104 through the shaft hole 206.

[0061] The shaft plate 104 and the mounting plate 205 are movably connected through the shaft hole 206, so that the shaft plate 104 can be rotated within a limited range between the two mounting plates 205, thereby cooperating with the driving member 103 and the elastic member 202 for left-right adjustment.

[0062] The connecting frame 203 is at one end away from the swing bridge 101 , and two connecting plates 207 are symmetrically arranged on both sides thereof, and the roller 204 is located between the two connecting plates 207 ; the surface of the roller 204 is provided with grinding sheets 208 distributed around its axial direction.

[0063] The roller 204 can rotate between the two connecting plates 207, thereby driving the grinding sheet 208 on its surface to rotate, thereby achieving the effect of grinding the blades.

[0064] The upper and lower ends of the drum 204 are respectively provided with an upper shell 301 and a lower shell 302 , and the upper shell 301 and the lower shell 302 are respectively fixedly connected to the connecting frame 203 and the connecting plates 207 at both sides thereof.

[0065] The upper shell 301 and the lower shell 302 are mainly used for auxiliary connection, fixing the roller 204 and dust prevention. At the same time, other equipment such as sensors can be set on the upper and lower shells 302.

[0066] The connecting plates 207 on both sides of the connecting frame 203 are respectively provided with distance measuring wheels 303 ; the distance measuring wheels 303 are coaxially arranged with the roller 204 , and the radius of the distance measuring wheels 303 is adapted to the radius of the roller 204 .

[0067] The distance measuring wheel 303 includes a measuring wheel 304 and a connecting rod 305, and the connecting rod 305 is fixedly connected to the connecting frame 203;

[0068] The edge of the distance measuring wheel 303 and the grinding sheet 208 can contact the surface of the blade at the same time, thereby determining that the grinding head has been fitted with the blade, and the driving member 103 powered by the cylinder drives the elastic member 202 to perform adaptive adjustment, and cooperates with the sensor to apply the preload force; the distance measuring wheel 303 is mainly used to cooperate with the sensor to determine the distance between the grinding head and the blade, and the preload force between the grinding head and the blade can be more accurately adjusted and controlled by the distance measuring wheel 303 contacting the blade.

[0069] A rotatable dustproof plate 306 is provided at one end of the upper shell 301 and the lower shell 302 away from the swing bridge 101, and a dustproof brush 307 is provided at the end of the dustproof plate 306; a dust removal channel 308 is also provided on the upper shell 301 and the lower shell 302; the dust removal channel 308 is connected to a dust removal device through a pipeline.

[0070] The distance measuring sensor 309 is located beside the dust removal passage 308, away from one end of the exit thereof;

[0071] The dustproof plate 306 and the dustproof brush 307 are mainly used to collect the dust generated by grinding the blades into the upper and lower shells 302. The dust removal channel 308 is connected with the upper and lower shells 302, and the dust is discharged through the dust removal channel 308; the dust removal device can be a dust collector, which is connected with the outlet of the dust removal channel 308 through a pipeline.

[0072] The grinding mechanism is also provided with sensors, including a distance sensor 309 , an upper stop sensor 310 and a lower stop sensor 311 ; the upper shell 301 and the lower shell 302 are respectively provided with distance sensors 309 , and the lower shell 302 is also provided with a lower stop sensor 311 .

[0073] The distance measuring sensor 309 is mainly used to detect the distance between the swing head 201 and the surface of the blade; the upper stop sensor 310 is mainly used to detect the upper edge of the blade to be polished, and the lower stop sensor 311 is mainly used to detect the lower edge of the blade. The upper and lower edges of the blade are detected by the upper stop sensor 310 and the lower stop sensor 311, thereby achieving complete polishing. At the same time, it is convenient to adjust the position and direction when reaching the edge of the blade to be polished, and continue to polish another area.

[0074] The telescopic arm includes a fixed arm 401 , a first connecting arm 402 , and a second connecting arm 403 which are slidably connected in sequence; the second connecting arm 403 is connected to the swing bridge 101 , and the fixed arm 401 is connected to the lifting frame; the upper stop sensor 310 is arranged on the fixed arm 401 .

[0075] Slide rails and sliders may be provided between the fixed arm 401 , the first connecting arm 402 , and the second connecting arm 403 , and the first connecting arm 402 and the second connecting arm 403 may be extended and contracted in a sequentially sleeved manner.

[0076] The working principle of a blade grinding mechanism provided by the utility model is to control the grinding mechanism, adjust the telescopic arm to the vicinity of the blade surface to be ground, and determine the initial grinding position when the upper stop sensor 310 detects the blade; use the cylinder to provide power, the driving member 103 pushes the elastic member 202, and the swing head 201 is made to fit on the blade surface through the elastic member 202, and a pre-tightening force is applied, and the pre-tightening force is kept constant to grind the blade surface; use the upper and lower distance measuring sensors 309 to work together to adjust the posture of the grinding head in real time; when the lower stop sensor 311 cannot detect the blade, stop grinding, adjust the position of the grinding mechanism again, and repeat the operation. Through the driving member 103, the elastic member 202 and the sensor, the swing head 201 can be adaptively floated on the blade surface, ensuring the grinding effect and pressure control, and improving the grinding quality.

[0077] According to the disclosure and teaching of the above description, the technical personnel in the field to which the utility model belongs can also change and modify the above implementation. Therefore, the utility model is not limited to the specific implementation methods disclosed and described above, and some modifications and changes to the utility model should also fall within the scope of protection of the claims of the utility model. In addition, although some specific terms are used in this specification, these terms are only for the convenience of description and do not constitute any limitation to the utility model.

Claims

1. A blade grinding mechanism, comprising a telescopic arm arranged on a lifting frame and a grinding assembly connected to the end of the telescopic arm; characterized in that: The polishing assembly comprises a swing bridge and a swing head which are sequentially connected to the telescopic arm, wherein the middle portion of the swing bridge is movably connected to the swing head via a longitudinal fixed shaft; elastic members are respectively provided at both ends of a side of the swing head connected to the swing bridge, and the other ends of the elastic members are respectively connected to the two ends of the swing bridge; One end of the swing bridge connected to the telescopic arm has a transversely arranged driving shaft, and the swing bridge is driven to swing up and down by the driving shaft; driving parts are respectively connected to the two sides of the driving shaft, and the driving parts are respectively connected to the elastic parts on the side, and drive the elastic parts to push the swing head to swing left and right.

2. A blade grinding mechanism according to claim 1, characterized in that: The swing bridge includes a swing arm, a driving member and a driving shaft. The swing arm includes an axis plate provided with an axis hole, and a swinging part and a connecting part connected to both sides of the axis plate. The swinging part is provided with a through hole, and the elastic member is connected to the driving member through the through hole of the swinging part.

3. A blade grinding mechanism according to claim 2, characterized in that: The connecting part is arranged in parallel on both sides of the driving shaft and connected with the swinging part. One side of the driving member is connected with the driving shaft, and the other side thereof is fixed on the connecting part.

4. A blade grinding mechanism according to claim 2, characterized in that: The swing head includes a connecting frame movably connected to the swing arm and a rotatable roller arranged on the connecting frame; one side of the connecting frame connected to the swing arm is provided with two upper and lower mounting plates parallel to each other, the shaft plate of the swing arm is located between the upper and lower mounting plates, and an shaft hole corresponding to the shaft plate is provided in the middle of the mounting plate, and the mounting plate is movably connected to the shaft plate through the shaft hole.

5. A blade grinding mechanism according to claim 4, characterized in that: The connecting frame is at one end away from the swing bridge, and two connecting plates are symmetrically arranged on both sides thereof, and the roller is located between the two connecting plates; and grinding sheets are arranged on the surface of the roller around its axial direction.

6. A blade grinding mechanism according to claim 5, characterized in that: An upper shell and a lower shell are respectively arranged at the upper and lower ends of the drum, and the upper shell and the lower shell are respectively fixedly connected to the connecting frame and the connecting plates at both sides thereof.

7. A blade grinding mechanism according to claim 5, characterized in that: The connecting plates on both sides of the connecting frame are respectively provided with distance measuring wheels; the distance measuring wheels are coaxially arranged with the roller, and the radius of the distance measuring wheels is adapted to the radius of the roller.

8. A blade grinding mechanism according to claim 6, characterized in that: The grinding mechanism is also provided with a sensor; the sensor includes a distance sensor, an upper stop sensor and a lower stop sensor; the upper shell and the lower shell are respectively provided with a distance sensor, and the lower shell is also provided with a lower stop sensor.

9. A blade grinding mechanism according to claim 6, characterized in that: A rotatable dustproof plate is provided at one end of the upper shell and the lower shell away from the swing bridge, and a dustproof brush is provided at the end of the dustproof plate; a dust removal channel is also provided on the upper shell and the lower shell; the dust removal channel is connected to a dust removal device through a pipeline.

10. A blade grinding mechanism according to claim 8, characterized in that: The telescopic arm comprises a fixed arm, a first connecting arm and a second connecting arm which are slidably connected in sequence; the second connecting arm is connected to the swing bridge, and the fixed arm is connected to the lifting frame; the upper stop sensor is arranged on the fixed arm.

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