CN113802903B

CN113802903B - Stopping and taking method based on AGV trolley transfer vehicle

Info

Publication number: CN113802903B
Application number: CN202111163916.5A
Authority: CN
Inventors: 蒋强; 万银; 刘诚
Original assignee: Chongqing University of Technology
Current assignee: Chongqing University of Technology
Priority date: 2021-09-30
Filing date: 2021-09-30
Publication date: 2023-04-07
Anticipated expiration: 2041-09-30
Also published as: CN113802903A

Abstract

The invention discloses a parking and taking method for transferring vehicles based on an AGV (automated guided vehicle), wherein a waiting parking position for the vehicle to be parked is arranged at an entrance of a parking lot, and a vehicle taking position for the vehicle to be taken is arranged at an exit of the parking lot; the AGV dolly includes the automobile body, the automobile body is by the rectangular frame structure that four steel end to end that the level set up formed, and be provided with many horizontal poles along automobile body length direction interval in the automobile body, in order to separate into a plurality of unequal rectangle installation regions of size with the automobile body, the installation region that is located both ends around the automobile body is walking steering mechanism installation region, be preceding frame installation region and back frame installation region between being located two walking steering mechanism installation regions respectively, fixed mounting walking steering mechanism is distinguished in two walking steering mechanism installation regions, frame and back frame installation region correspond respectively just before the suspension installation frame and back frame installation region in the front. The invention has simple stopping and taking process and stable running, can realize in-situ steering and has better clamping stability for the vehicle tire.

Description

Stopping and taking method based on AGV trolley transfer vehicle

Technical Field

The invention relates to the technical field of AGV trolleys, in particular to a stopping and taking method for transferring vehicles based on the AGV trolleys.

Background

The AGV trolley is a transport vehicle which is provided with an electromagnetic or optical automatic guiding device and can run along a specified guiding path, comprises a running and stopping device and a safety protection device and has various transfer functions, the AGV trolley can automatically transport a vehicle to a destination from a starting point under the condition that the AGV trolley does not need to be manually driven by self, and people can use the AGV trolley conveniently.

For example, the invention patent with the publication number of CN110700663A discloses a vehicle parking method based on AGV, a waiting position where the AGV waits is arranged at an entrance of a parking lot, the AGV is positioned on the waiting position and is provided with a front frame and a rear frame, and at least one frame can move forwards and backwards to change the distance between the front frame and the rear frame so as to adapt to the distance between the front wheel and the rear wheel of the vehicle; four groups of clamping arms corresponding to the four wheels are arranged on the AGV trolley, and each group of clamping arms is provided with two clamping arms; two groups of clamping arms corresponding to the two front wheels are positioned on the left side and the right side of the front frame, and two groups of clamping arms corresponding to the two rear wheels are positioned on the left side and the right side of the rear frame; when the AGV is stopped, all the clamping arms are folded in the AGV trolley and are in a longitudinal state, the front frame and the rear frame are adjusted in place according to the distance between the front wheel and the rear wheel of the vehicle, the two clamping arms in each group relatively rotate for 90 degrees and extend out to be in a transverse state, and the distance between the two clamping arms in each group is smaller than the diameter of the wheels in the transverse state.

The AGV in this scheme dolly direction of travel is limited, can only realize the fore-and-aft direction and remove. Secondly, when parking the vehicle, need have multilayer steel frame construction's hoisting frame, be equipped with the slide rail that supplies vehicle to transport the platform and remove on the hoisting frame, the AGV dolly will be waited to park on the vehicle transports the platform from waiting the bus position lateral shifting, and the rethread vehicle transports the platform and removes to the corresponding layer parking stall before, and the AGV dolly will be waited to park again at last and remove to the parking stall to accomplish the vehicle and park. And thirdly, the vehicle taking process is just opposite, and in order to ensure that the vehicle head of the vehicle to be taken faces the garage outlet, the direction of the vehicle head needs to be adjusted through a steering wheel. Finally, since the wheels have various sizes, the clamping arms cannot contact with the tire tread during the clamping process of the clamping arms, and the clamping is realized through a lifting process. Therefore, the conventional AGV trolley is complex in movement parking process, single in driving direction, high in cost and capable of being realized through the cooperation of multiple mechanisms. Therefore, the AGV trolley which is simple in structure, stable in running, capable of steering and capable of clamping vehicles and better in stability is particularly important for transferring the vehicles in the parking lot to the AGV trolley.

Disclosure of Invention

Aiming at the defects of the prior art, the technical problems to be solved by the invention are as follows: how to provide a stop and get process simple, the steady running can turn to in situ, can be to the better method of stopping and getting based on AGV dolly transportation vehicle of vehicle tire centre gripping stability.

In order to solve the technical problems, the invention adopts the following technical scheme:

a parking method based on AGV trolley transfer vehicles is characterized in that waiting parking positions for the vehicles to be parked are arranged at an entrance of a parking lot, and taking positions for the vehicles to be taken are arranged at an exit of the parking lot;

the AGV comprises a vehicle body, wherein the vehicle body is of a rectangular frame structure formed by connecting four horizontally arranged steel materials end to end, a plurality of cross rods are arranged in the vehicle body at intervals along the length direction of the vehicle body to divide the vehicle body into a plurality of rectangular mounting areas with different sizes, the mounting areas at the front end and the rear end of the vehicle body are respectively walking steering mechanism mounting areas, a front frame mounting area and a rear frame mounting area are respectively arranged between the two walking steering mechanism mounting areas, and walking steering mechanisms are respectively and fixedly mounted in the two walking steering mechanism mounting areas to drive the AGV to run and steer; the front frame mounting area and the rear frame mounting area correspond to each other respectively and are provided with a front frame and a rear frame in a suspension manner, a moving frame is movably arranged between the rear frame and the rear frame mounting area, the rear frame is arranged on the moving frame in a suspension manner, and the moving frame adjusts the position of the moving frame in the rear frame mounting area back and forth through a translation device so as to change the distance between the moving frame and the front frame and correspond to vehicles with different wheelbases; lifting mechanisms are respectively arranged between the front frame installation area and the front frame and between the movable frame and the rear frame so as to suspend the lifting vehicle and the ground; the front frame is provided with a front clamping device for simultaneously clamping the left and right front wheels of the vehicle, and the rear frame is provided with a rear clamping device for simultaneously clamping the left and right rear wheels of the vehicle; the front clamping device and the rear clamping device respectively comprise a left group of clamping arms and a right group of clamping arms, and each group of clamping arms is provided with two clamping arms for clamping the wheel at the corresponding position; in a waiting and stopping state, all clamping arms are folded in the AGV trolley and are in a longitudinal state;

the parking process is as follows:

1) The vehicle to be parked drives into the waiting parking position, the position in front of the vehicle is controlled through the vehicle stopper, after the vehicle is parked in place in the waiting parking position, a driver leaves, and the vehicle stopper in the waiting parking position is withdrawn so as not to influence the subsequent operation of the vehicle;

2) The AGV trolley runs to a waiting stop entrance through a walking steering mechanism, and the angle and the running direction of the AGV trolley are adjusted according to sensors on the left side and the right side of the waiting stop entrance to drive into the waiting stop so as to keep the AGV trolley under a vehicle chassis, and the AGV trolley stops running when the front end of the AGV trolley body is in contact with a stop block on the waiting stop;

3) Two groups of clamping arms of a front frame of the AGV trolley are respectively unfolded towards the outer side of the trolley body, two clamping arms in each group respectively rotate by 90 degrees and extend out of the clamping arms to be in a transverse state, and the distance between the two groups of clamping arms of the front frame is smaller than the diameter of a wheel in the transverse state;

4) The AGV trolley translation device drives the moving frame to move to a set position in the direction of the front frame, one clamping arm in each group of clamping arms on the rear frame, which is close to the front frame, rotates by 90 degrees and extends out of the rear frame to be in a transverse state, after the clamping arms are in the transverse state, the translation device drives the moving frame to move away from the front frame and to be close to a rear wheel of the vehicle, when the clamping arms of the rear frame in the transverse state are in contact with the rear wheel, the translation device stops moving, the other clamping arm in each group of clamping arms on the rear frame rotates by 90 degrees and extends out of the clamping arms to be in the transverse state, and the distance between the two groups of clamping arms of the rear frame is smaller than the diameter of the wheel in the transverse state; in the process that the rear frame clamping arm clamps the rear wheel, the front frame lifting mechanism starts to lift the front frame under the driving of the lifting motor, and stops lifting and maintains the front frame at a set height after the front frame is lifted to the set height; after the rear frame clamping arm clamps the rear wheel in place and the front frame is lifted in place, the rear frame lifting mechanism starts to lift the rear frame under the driving of the lifting motor, and stops lifting and maintains the rear frame at a set height after the rear frame is lifted to the set height;

5) The AGV trolley carries the vehicle to be parked to reach the entrance of the parking space, then the angle and the direction of the vehicle entering the parking space are adjusted through the walking steering mechanism according to the sensor on the parking space, and the vehicle stops running when the front end of the vehicle body of the AGV trolley is in contact with the stop blocks on the parking space; the two lifting mechanisms respectively drive the corresponding front frame or the corresponding rear frame to descend so that the wheels of the vehicle to be parked fall to the ground, and all the clamping arms are retracted to a vertical state of waiting for parking;

6) The AGV trolley drives away from the parking space and goes to the designated position, and the designated position comprises a waiting position for executing the next parking task and a parking space with a parked car for executing the car taking task or waiting for a task instruction in a waiting area.

The vehicle taking process comprises the following steps:

1) The AGV trolley runs to a parking space entrance of a vehicle to be taken through a walking steering mechanism, and the angle and the running direction are adjusted to drive into the parking space according to sensors on the left side and the right side of the parking space entrance so as to keep the AGV trolley under a vehicle chassis, and the AGV trolley stops running when the front end of the AGV trolley body is in contact with a stop block on the parking space;

2) The two groups of clamping arms of the front frame of the AGV trolley are respectively unfolded towards the outer side of the trolley body, two clamping arms in each group rotate by 90 degrees and extend out of the clamping arms to be in a transverse state, and the distance between the two groups of clamping arms of the front frame is smaller than the diameter of a wheel in the transverse state;

3) The AGV trolley translation device drives the moving frame to move to a set position in the direction of the front frame, one clamping arm in each group of clamping arms on the rear frame, which is close to the front frame, rotates by 90 degrees and extends out of the rear frame to be in a transverse state, after the clamping arms are in the transverse state, the translation device drives the moving frame to move away from the front frame and to be close to a rear wheel of the vehicle, when the clamping arms of the rear frame in the transverse state are in contact with the rear wheel, the translation device stops moving, the other clamping arm in each group of clamping arms on the rear frame rotates by 90 degrees and extends out of the clamping arms to be in the transverse state, and the distance between the two groups of clamping arms of the rear frame is smaller than the diameter of the wheel in the transverse state; in the process that the rear frame clamping arm clamps the rear wheel, the front frame lifting mechanism starts to lift the front frame under the driving of the lifting motor, and stops lifting and maintains the front frame at a set height after the front frame is lifted to the set height; after the rear frame clamping arm clamps the rear wheel in place and the front frame is lifted in place, the rear frame lifting mechanism starts to lift the rear frame under the driving of the lifting motor, and stops lifting and maintains the rear frame at a set height after the rear frame is lifted to the set height;

4) The AGV trolley slowly exits from the parking space through the walking steering mechanism, runs to the entrance of the car taking place, and runs into the car taking place by adjusting the angle and the running direction according to the sensors on the left side and the right side of the entrance of the car taking place, and stops running when the front end of the body of the AGV trolley contacts with the stopper on the car taking place;

5) The two lifting mechanisms of the AGV trolley respectively drive the corresponding front frame or the rear frame to descend so that the wheels of the vehicle to be taken fall to the ground, and all the clamping arms return to a longitudinal state of waiting for stopping;

6) The AGV drives away from the parking space and goes to the designated position, and the designated position comprises a waiting position for executing the next parking task, and the parking space with the parked car is used for executing the car taking task or waiting for a task instruction in a waiting area.

Furthermore, the front clamping device and the rear clamping device both comprise two clamping arm motors and two horizontal first scroll rods which are arranged at intervals front and back along the width direction of the vehicle body, scroll teeth are arranged at two ends of each first scroll rod, clamping arms which are used for clamping wheels and are in a horizontal plate shape are correspondingly arranged above two ends of each first scroll rod respectively, a clamping arm shaft is fixedly arranged at one end of each clamping arm, penetrates through the corresponding front frame or the corresponding rear frame and is rotatably connected with the corresponding front frame or the corresponding rear frame, a first turbine is connected to the lower end key of each clamping arm shaft, and the first turbine is meshed with the scroll teeth; the inner side wall of the front frame mounting area and the inner side wall of the movable frame are respectively and correspondingly provided with a shaft sleeve for a first scroll bar to horizontally pass through, and the first scroll bar is rotationally connected with the shaft sleeve; two arm lock motors are respectively fixedly installed on the corresponding front frame and the corresponding rear frame, output shafts of the two arm lock motors are respectively in driving connection with the corresponding first scroll bars through a bevel gear set, so that the front and rear arm locks corresponding to the front frame and the rear frame are unfolded outwards of the vehicle body, the front and rear arm locks are matched at intervals to clamp the wheel, and the distance between the two arm locks in each group of arm locks is smaller than the wheel diameter of the wheel.

Further, the translation device includes translation motor and the backup pad that sets up along automobile body length direction bilateral symmetry level, and backup pad fixed mounting is in the automobile body below, the spout has been seted up along backup pad length direction at two backup pad upper surfaces, the spout is located the automobile body inboard, one of them backup pad upper surface just is located spout one side horizontal installation and has first bar tooth, translation motor fixed mounting is on removing the frame, remove to install on the frame with spout matched with gyro wheel, install the gear with first bar tooth engaged with on translation motor's the output shaft, in order to drive to remove the frame along automobile body length direction back-and-forth movement.

Furthermore, after all the clamping arms are unfolded, a downward-inclined turnover plate is arranged towards the surface of the tire to be clamped, and the turnover plate is rotatably connected with the corresponding clamping arms; a sensor is arranged on one of the left and right clamping arms of the rear clamping device, which is close to the front frame, a signal trigger block is fixedly arranged on one end face of the turnover plate, which is close to the sensor, the output of the sensor is connected with a controller, the controller is connected with a translation motor, when the signal trigger block is aligned with the sensor in the turnover process along with the turnover plate, the translation of the rear frame is in place, and the controller controls the translation motor to stop working at the moment; a return spring is arranged between the back of the turnover plate and the clamping arm, and the lower end of the turnover plate slantly faces downwards to the direction of the wheel to be clamped in a holding mode in a natural state.

Furthermore, the lifting mechanisms on the front frame mounting area and the front frame, and on the moving frame and the rear frame respectively comprise a lifting motor and a transmission shaft horizontally arranged along the length direction of the vehicle body, two ends of the transmission shaft respectively penetrate through the corresponding front frame and the corresponding rear frame and are respectively in rotary connection with the corresponding front frame and the corresponding rear frame, and gears are fixedly mounted at two ends of the transmission shaft; the inner side wall of the front frame mounting area and the inner side wall of the movable frame are respectively provided with a vertically mounted second strip-shaped tooth matched with the gears at the two ends of the corresponding transmission shaft, and the two second strip-shaped teeth are meshed with the gears at the two ends of the transmission shaft; the lifting motor is fixedly arranged on the front frame and the rear frame through a motor support respectively, and an output shaft of the lifting motor is in driving connection with the transmission shaft through a transmission belt or a bevel gear set so as to lift and lower the front frame and the rear frame respectively.

Furthermore, remove frame inside wall and preceding frame installation region inside wall and respectively the bilateral symmetry vertically install the polylith stopper, rotate respectively in the front on frame and the back frame and install the pulley of laminating mutually with terminal surface about corresponding the stopper.

Furthermore, each two-walking steering mechanism comprises two walking seats and a fixing plate which is horizontally and fixedly installed along the width direction of the vehicle body and is positioned above the vehicle body, scroll rod installation blocks are vertically installed on the lower surface of the fixing plate in a bilateral symmetry mode along the length direction, scroll rod holes are formed in the two scroll rod installation blocks in a one-to-one correspondence mode, second scroll rods are rotatably connected in the scroll rod holes, and scroll teeth are arranged at the left end and the right end of each second scroll rod; the walking seat is of a rectangular shell structure formed by surrounding four vertical plates and a top plate, a walking wheel and a walking motor are rotatably arranged in the walking seat and fixedly arranged in the walking seat, the peripheral surface of the walking wheel is in contact with the ground, and an output shaft of the walking motor is in driving connection with a rotating shaft of the walking wheel through a gear set so as to drive the walking to rotate; a turbine shaft is arranged between each top plate and the fixing plate, one end of each turbine shaft is fixedly connected with the corresponding top plate, the other end of each turbine shaft is rotatably installed on the fixing plate through a turbine shaft installation block, a second turbine is fixedly installed on each turbine shaft, and the second turbine is meshed with the turbine teeth on the second worm; and a steering motor is further installed on the fixing plate, and an output shaft of the steering motor is in driving connection with the second scroll bar through a driving belt so as to drive the two walking seats to rotate in the same direction.

Furthermore, damping mechanisms are symmetrically arranged between the vertical plate and the top plate of each walking seat in a left-right mode, so that each walking wheel can be in better contact with the ground.

Compared with the prior art, the invention has the beneficial effects that:

1. the AGV trolley body is provided with the combined front frame and the combined rear frame, the distance between the rear frame and the front frame is changed by the front and back movement of the rear frame so as to adapt to the wheel base of different vehicles, and compared with a separated type trolley body, the distance control system is not needed to maintain the distance between the separated type trolley bodies; when the rear frame moves back and forth to change the distance between the rear frame and the front frame so as to adapt to different vehicle wheelbases, the front frame lifting mechanism starts to lift, at the moment, the rear wheels of the vehicle are used as lifting fulcrums, and after the front frame is lifted in place, the rear frame is lifted again, so that the reliability is better, and the efficiency is not influenced.

2. Every arm lock rotates and connects the returning face plate, and the returning face plate contacts and produces the follow-up rotation with the tire, and increase and tire tread laminating degree realize the better laminating of arm lock and wheel, and the arm lock atress is better.

3. According to the AGV turning device, the AGV trolley is driven and turned into a whole, the turning and walking flexibility is better, the direction can be adjusted in situ, the front of the vehicle head faces the front when the vehicle is taken out of a warehouse, the special arrangement of a rotary turntable is avoided, the vehicle head faces the required direction, and in addition, a set of mechanism needs to be additionally arranged, so that the complexity of the whole structure is increased.

4. The car body is divided into a plurality of mounting areas with different sizes, and each part of the AGV car is mounted in the corresponding mounting area, and the AGV car is clear in structure, independent of each other, free of interference and convenient to mount and maintain.

5. The moving frame is driven to move along the second strip-shaped teeth through the translation motor so as to move the rear frame back and forth, and the adjusting structure is simple and light and corresponds to vehicles with different wheelbases.

6. And the four walking seats are respectively provided with a damping mechanism so as to cope with the rugged road surface in the running process of the AGV trolley and keep each walking wheel of the AGV trolley to be always contacted with the ground.

Drawings

For a better understanding of the objects, solutions and advantages of the present invention, reference will now be made in detail to the present invention, which is illustrated in the accompanying drawings, in which:

FIG. 1 is a schematic view of the overall structure of the present invention;

FIG. 2 is an enlarged view of the point A in FIG. 1;

fig. 3 is a partial bottom view of fig. 1.

In the figure: the device comprises a vehicle body 1, a front vehicle frame 2, a rear vehicle frame 3, a moving frame 4, a clamping arm motor 5, a first scroll bar 6, a clamping arm 7, a clamping arm shaft 8, a first turbine 9, a turnover plate 10, a sensor 11, a signal trigger block 12, a translation motor 13, a support plate 14, a first strip-shaped tooth 15, a lifting motor 16, a transmission shaft 17, a second strip-shaped tooth 18, a motor support 19, a limiting block 20, a pulley 21, a vertical plate 22, a fixing plate 23, a second scroll bar 24, a top plate 25, a walking wheel 26, a walking motor 27, a second turbine 28, a steering motor 29, a transmission belt 30 and a spring damper 31.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

As shown in fig. 1, 2 and 3, in the parking method based on an AGV for transporting a vehicle, a waiting position for the vehicle to be parked is set at an entrance of a parking lot, and a parking position for the vehicle to be parked is set at an exit of the parking lot.

The AGV comprises a vehicle body 1, wherein the vehicle body 1 is of a rectangular frame structure formed by connecting four horizontally arranged steel materials end to end, a plurality of cross rods are arranged in the vehicle body at intervals along the length direction of the vehicle body to divide the vehicle body into a plurality of rectangular mounting areas with different sizes, the mounting areas at the front end and the rear end of the vehicle body 1 are respectively walking steering mechanism mounting areas, a front frame mounting area and a rear frame mounting area are respectively arranged between the two walking steering mechanism mounting areas, and walking steering mechanisms are respectively and fixedly mounted in the two walking steering mechanism mounting areas to drive the AGV to run and steer; the front frame mounting area and the rear frame mounting area correspond to each other respectively and are provided with a front frame 2 and a rear frame 3 in a suspension manner, a moving frame 4 is movably mounted between the rear frame 3 and the rear frame mounting area, the rear frame 3 is mounted on the moving frame 4 in a suspension manner, and the moving frame 4 adjusts the position of the moving frame in the rear frame mounting area back and forth through a translation device so as to change the distance between the moving frame 4 and the front frame 2 and correspond to vehicles with different wheelbases; lifting mechanisms are respectively arranged between the front frame mounting area and the front frame 2 and between the movable frame 4 and the rear frame 3, so that the lifted vehicle is suspended from the ground; a front clamping device for simultaneously clamping the left and right front wheels of the vehicle is arranged on the front frame 2, and a rear clamping device for simultaneously clamping the left and right rear wheels of the vehicle is arranged on the rear frame 3; the front clamping device and the rear clamping device respectively comprise a left clamping arm and a right clamping arm, and each clamping arm is provided with two clamping arms for clamping the wheel at the corresponding position; and in the waiting and stopping state, all clamping arms are folded in the AGV trolley and are in a longitudinal state.

The parking process is as follows:

1) The AGV trolley waits for the vehicle to be parked to enter outside the waiting position, the vehicle to be parked enters the waiting position, the position in front of the vehicle is controlled through the vehicle stopper, after the vehicle is parked in place in the waiting position, the driver leaves, and the vehicle stopper in the waiting position returns to avoid influencing the subsequent operation of the vehicle;

2) The AGV trolley runs to a waiting stop entrance through a walking steering mechanism, and the angle and the running direction of the AGV trolley are adjusted according to sensors on the left side and the right side of the waiting stop entrance to drive into the waiting stop so as to keep the AGV trolley under a vehicle chassis, and the AGV trolley stops running when the front end of the AGV trolley body 1 is contacted with a stop block on the waiting stop;

3) Two groups of clamping arms of a front frame 2 of the AGV trolley are respectively unfolded towards the outer side of the trolley body, two clamping arms in each group respectively rotate by 90 degrees and extend out of the clamping arms to be in a transverse state, and the distance between the two groups of clamping arms of the front frame is smaller than the diameter of a wheel in the transverse state;

4) The AGV trolley translation device drives the moving frame to move to a set position in the direction of the front frame, the clamp arm, close to the front frame, in each group of clamp arms on the rear frame rotates by 90 degrees and extends out of the rear frame to be in a transverse state, after the clamp arms are in the transverse state, the translation device drives the moving frame to move away from the front frame and close to the rear wheel of the vehicle, when the clamp arm, in the transverse state, of the rear frame is in contact with the rear wheel, the translation device stops moving, the other clamp arm in each group of clamp arms on the rear frame rotates by 90 degrees and extends out of the clamp arm to be in the transverse state, and in the transverse state, the distance between the two groups of clamp arms of the rear frame is smaller than the diameter of the wheel; in the process that the rear frame clamping arm clamps the rear wheel, the front frame lifting mechanism starts to lift the front frame under the driving of the lifting motor, and stops lifting and maintains the height after the front frame is lifted to the set height; after the rear frame clamping arm clamps the rear wheel in place and the front frame is lifted in place, the rear frame lifting mechanism starts to lift the rear frame under the driving of the lifting motor, and stops lifting and maintains the rear frame at a set height after the rear frame is lifted to the set height;

6) The AGV trolley drives away from the parking space and goes to a designated position, wherein the designated position comprises a waiting position for executing the next parking task, and the parking space with the parked car is used for executing a car taking task or waiting for a task instruction in a waiting area;

the vehicle taking process comprises the following steps:

1) The AGV trolley runs to a parking space entrance of a vehicle to be taken through the walking steering mechanism, and according to sensors on the left side and the right side of the parking space entrance, the angle and the running direction are adjusted to drive into the parking space so as to keep the AGV trolley under a vehicle chassis, and when the front end of the AGV trolley body is in contact with a stop block on the parking space, the AGV trolley stops running;

2) Two groups of clamping arms of a front frame of the AGV trolley are respectively unfolded towards the outer side of the trolley body, two clamping arms in each group respectively rotate by 90 degrees and extend out of the clamping arms to be in a transverse state, and the distance between the two groups of clamping arms of the front frame is smaller than the diameter of a wheel in the transverse state;

3) The AGV trolley translation device drives the moving frame to move to a set position in the direction of the front frame, the clamp arm, close to the front frame, in each group of clamp arms on the rear frame rotates by 90 degrees and extends out of the rear frame to be in a transverse state, after the clamp arms are in the transverse state, the translation device drives the moving frame to move away from the front frame and close to the rear wheel of the vehicle, when the clamp arm, in the transverse state, of the rear frame is in contact with the rear wheel, the translation device stops moving, the other clamp arm in each group of clamp arms on the rear frame rotates by 90 degrees and extends out of the clamp arm to be in the transverse state, and in the transverse state, the distance between the two groups of clamp arms of the rear frame is smaller than the diameter of the wheel; in the process that the rear frame clamping arm clamps the rear wheel, the front frame lifting mechanism starts to lift the front frame under the driving of the lifting motor, and stops lifting and maintains the front frame at a set height after the front frame is lifted to the set height; after the rear frame clamping arm clamps the rear wheel in place and the front frame is lifted in place, the rear frame lifting mechanism starts to lift the rear frame under the driving of the lifting motor, and stops lifting and maintains the rear frame at a set height after the rear frame is lifted to the set height;

4) The AGV trolley slowly exits from the parking space through the walking steering mechanism, runs to the entrance of the car taking place, and runs into the car taking place by adjusting the angle and the running direction according to the sensors on the left side and the right side of the entrance of the car taking place, and stops running when the front end of the trolley body of the AGV trolley contacts with the stopper on the car taking place;

6) The AGV trolley drives away from the parking space and goes to the designated position, and the designated position comprises a waiting parking space for executing the next parking task and a parking space with a parked car for executing the car taking task or waiting for a task instruction in a waiting area.

According to the method, the combined front frame and the combined rear frame are arranged on the AGV trolley body, the distance between the rear frame and the front frame is changed by moving the rear frame back and forth so as to adapt to the wheel base of different vehicles, and compared with a separated type trolley body, the distance control system is omitted for maintaining the distance between the separated type trolley bodies; when the rear frame moves back and forth to change the distance between the rear frame and the front frame so as to adapt to different vehicle wheelbases, the front frame lifting mechanism starts to lift, at the moment, the rear wheels of the vehicle are used as lifting fulcrums, and after the front frame is lifted in place, the rear frame is lifted again, so that the reliability is better, and the efficiency is not influenced.

The vehicle body 1 is divided into a plurality of mounting areas with different sizes, and each component of the AGV trolley is mounted in the corresponding mounting area, so that the AGV trolley is clear in structure, independent from each other and free of interference, and is convenient to mount and maintain. The front frame mounting area and the rear frame mounting area are respectively correspondingly provided with a front frame 2 and a rear frame 3 in a suspension manner, a movable frame 4 is movably mounted between the rear frame 3 and the rear frame mounting area, the rear frame is mounted on the movable frame in a suspension manner, and the position of the movable frame 4 in the rear frame mounting area is adjusted forwards and backwards through a translation device so as to deal with vehicles with different wheelbases; the front wheel and the rear wheel of the vehicle are clamped by the front clamping device and the rear clamping device respectively, and the wheels of the vehicle are lifted by the lifting mechanism to be suspended on the ground; at last through walking with turn to in walking steering mechanism of an organic whole, transport the vehicle to appointed parking stall from waiting for the parking stall, transport the vehicle to getting the parking stall from appointed parking stall again to the realization is to stopping of vehicle, getting the transportation process, simple structure, it is steady to go, but pivot steering can be better to the accurate centre gripping of vehicle tire and stability.

In the present embodiment, since the front clamping device and the rear clamping device have the same structure and are respectively installed on the corresponding front frame and the corresponding rear frame, the front and rear clamping devices are respectively described, specifically, referring to fig. 2 and 3, the front clamping device includes two clamping arm motors 5 and two horizontal first scroll bars 6 arranged at intervals in the front-rear direction of the vehicle body, two ends of the first scroll bars are provided with scroll teeth, two ends of each first scroll bar 6 are respectively provided with a clamping arm 7 which is used for clamping a wheel and is in a horizontal plate shape above the front frame 2, one end of each clamping arm is fixedly installed with a clamping arm shaft 8, the clamping arm shaft 8 penetrates through the front frame 2 (steel material in the length direction) and is rotatably connected with the front frame 2, the lower end of each clamping arm shaft 8 is keyed with a first turbine 9, and the first turbine 9 is engaged with the scroll teeth; the inner side walls of the front frame mounting areas are respectively and correspondingly provided with shaft sleeves for the first scroll bars 6 to horizontally penetrate through, and the first scroll bars 6 are rotatably connected with the shaft sleeves; two arm lock motors 5 are respectively fixedly installed on the front frame 2, output shafts of the two arm lock motors 5 are respectively in driving connection with corresponding first scroll bars 6 through bevel gear sets, so that the front and rear arm locks on the front frame are expanded outwards of the vehicle body 1, the front and rear arm locks are matched at intervals to clamp the vehicle wheel, and the distance between the two arm locks 7 in each arm lock set is smaller than the wheel diameter of the vehicle wheel.

The rear clamping device comprises two clamping arm motors 5 and two horizontal first scroll bars 6 which are arranged at intervals in the front and rear direction of the vehicle body, vortex teeth are arranged at two ends of each first scroll bar 6, clamping arms 7 which are used for clamping wheels and are in a horizontal plate shape are respectively and correspondingly arranged at two ends of each first scroll bar 6 above the rear vehicle frame 3, a clamping arm shaft 8 is fixedly arranged at one end of each clamping arm, the clamping arm shaft 8 penetrates through the rear vehicle frame 3 (steel in the length direction) and is rotatably connected with the rear vehicle frame 3, a first turbine 9 is connected to the lower end of each clamping arm shaft 8 through a key, and the first turbine 9 is meshed with the vortex teeth; the inner side walls of the movable frames are respectively and correspondingly provided with shaft sleeves for the first scroll bars 6 to horizontally pass through, and the first scroll bars 6 are rotationally connected with the shaft sleeves; two arm lock motors 5 are respectively fixedly installed on the rear frame 3, output shafts of the two arm lock motors 5 are respectively in driving connection with the corresponding first scroll bars 6 through a bevel gear set, so that the front and rear arm locks of the rear frame are expanded outwards towards the vehicle body 1, the front and rear arm locks are matched at intervals to clamp the wheel, and the distance between the two arm locks 7 in each group of arm locks is smaller than the wheel diameter of the wheel.

Thus, the front clamping device and the rear clamping device are respectively provided with two groups of clamping arms, each group of clamping arms comprises two clamping arms, and four groups of clamping arms are provided so as to clamp the wheel at the corresponding position; when concrete centre gripping, be close to the automobile body front end or keep away from two blocks of arm lock of automobile body front end in preceding frame or the two sets of arm lock of back frame be a set of, and through 6 rotations of arm lock motor 5 drive first scroll bar like this, first scroll bar 6 drives first turbine 9 and rotates, and first turbine 9 drives and presss from both sides arm shaft 8 and rotate, and the arm lock of both sides is the symmetry action under same motor drive to the realization is embraced simultaneously to press from both sides or is embraced the effect of pressing from both sides simultaneously to two rear wheels simultaneously to two front wheels. Each group of clamping arms 7 is independently controlled by a clamping arm motor 5, so that the outward expansion of the clamping arms in the vehicle lifting process or the driving process is avoided, and the clamping arms are connected by gears to be controlled more accurately.

In this embodiment, the translation device includes translation motor 13 and the backup pad 14 that sets up along automobile body length direction bilateral symmetry level, and backup pad 14 fixed mounting is in automobile body 1 below, the spout has been seted up along backup pad length direction at two backup pad 14 upper surfaces, the spout is located the automobile body inboard, one of them backup pad 14 upper surface and be located spout one side horizontal mounting have first bar tooth 15, translation motor 13 fixed mounting is on removing frame 4, remove and install the gyro wheel with spout matched with on the frame 4, install the gear with first bar tooth engaged with on translation motor 13's the output shaft, in order to drive and remove frame 4 along the back-and-forth movement of automobile body 1 length direction.

Like this, through realize the back-and-forth movement to back frame 3 in the back frame installation region of automobile body 1 to corresponding different wheel base vehicles, comparing in the disconnect-type automobile body, saved and still need adopt the interval that the disconnect-type automobile body was maintained to the distance control system, this scheme utilizes whole AGV dolly automobile body to realize preceding frame 2 and back frame 3's unity, adjusts simple structure, and is light.

In the specific embodiment, a downwardly inclined flip plate 10 is arranged towards the side to be clamped with the tire after all the clamp arms in the front clamping device or the rear clamping device are unfolded, the flip plate 10 is rotatably connected with the clamp arms, a sensor 11 is mounted on one of the left and right groups of clamp arms of the rear clamping device, which is close to the front frame, a signal trigger block 12 is fixedly mounted on one end face of the flip plate 10, which is close to the sensor, the output of the sensor is connected with a controller, the controller is connected with a translation motor, when the signal trigger block 12 is aligned with the sensor 11 in the turnover process of the flip plate 10, the translation of the rear frame is in place, the controller controls the translation motor to stop working, a reset spring is arranged between the back of the flip plate and the clamp arms, and the lower end of the flip plate slantly faces downwards to be clamped with the direction of the tire in a natural state.

Therefore, in the rotating process of each clamping arm 7, the turnover plate 10 is contacted with the tire to enable the turnover plate 10 to rotate, and the attaching degree of the turnover plate 10 and the tire tread is increased; when the signal triggering block 12 on the turnover plate is aligned with the sensor in the turnover process along with the turnover plate 10, the translation of the rear frame is in place, the sensor sends the generated electric signal to the controller, and the controller controls the translation motor 13 to stop working so as to accurately clamp the rear wheel. Through reset spring's setting, under natural state, the returning face plate lower extreme slant orientation is all the time waited to embrace and press from both sides the wheel direction to laminate with not unidimensional wheel side.

In this embodiment, since the two lifting mechanisms have the same structure and different installation positions, the lifting mechanisms on the front frame installation region and the front frame, the moving frame and the rear frame are respectively described, and referring to fig. 1, fig. 2 and fig. 3 in particular, the lifting mechanisms on the front frame installation region and the front frame include a lifting motor 16 and a transmission shaft 17 horizontally arranged along the length direction of the vehicle body 1, two ends of the transmission shaft 17 penetrate through the front frame 2 and are rotatably connected with the front frame, and two ends of the transmission shaft are fixedly provided with gears; second bar-shaped teeth 18 (the second bar-shaped teeth are arranged in the same direction or in opposite directions, and the tooth patterns of the second bar-shaped teeth face the outer side of the vehicle body) are vertically arranged on the inner side wall of the front vehicle frame mounting area and matched with the gears at the two ends of the transmission shaft, and the two second bar-shaped teeth 18 are meshed with the gears at the two ends of the transmission shaft 17; the lifting motor 16 is fixedly arranged on the front frame 2 through a motor support 19, and an output shaft of the lifting motor is in driving connection with the transmission shaft 17 through a transmission belt or a bevel gear set so as to lift and lower the front frame 2.

The lifting mechanisms on the movable frame and the rear frame comprise lifting motors 16 and transmission shafts 17 horizontally arranged along the length direction of the vehicle body 1, two ends of each transmission shaft 17 penetrate through the rear frame 3 and are rotationally connected with the rear frame, and gears are fixedly arranged at two ends of each transmission shaft; second bar-shaped teeth 18 (the second bar-shaped teeth are arranged in the same direction or opposite directions, and the tooth lines of the second bar-shaped teeth face the outer side of the vehicle body) are vertically arranged on the inner side wall of the front vehicle frame mounting area and matched with the gears at the two ends of the transmission shaft, and the two second bar-shaped teeth 18 are meshed with the gears at the two ends of the transmission shaft 17; the lifting motor 16 is fixedly arranged on the front frame 2 through a motor support 19, and an output shaft of the lifting motor is in driving connection with the transmission shaft 17 through a transmission belt or a bevel gear set so as to lift and lower the rear frame 3.

In this way, the lifting motor 16 drives the transmission shaft 17 to transmit, so that gears at two ends of the transmission shaft 17 move up and down along the length direction of the second strip-shaped teeth 18, and the lifting and the descending of the front frame 2 and the rear frame 3 are realized; the front frame 2 and the rear frame 3 are lifted or lowered independently through the lifting motor 16, when the rear frame 3 moves back and forth to change the distance between the rear frame 3 and the front frame 2 so as to adapt to different vehicle wheelbases, the lifting mechanism of the front frame 2 starts to lift, at the moment, the rear wheels of the vehicle are used as lifting fulcrums, after the front frame is lifted in place, the rear frame 3 is lifted again, the lifting is not carried out simultaneously, the reliability is better, and the efficiency is not influenced.

Referring to fig. 2, in specific implementation, in order to ensure that the front frame 2 and the rear frame 3 do not move up and down during operation of the lifting motor, a plurality of limiting blocks 20 are respectively and symmetrically vertically installed on two inner side walls of the movable frame 4 and two inner side walls of a front frame installation area along the length direction of the vehicle body 1, and pulleys 21 attached to the left end face and the right end face of the corresponding limiting blocks 20 are respectively and rotatably installed on the front frame 2 and the rear frame 3.

Therefore, when the front frame 2 and the rear frame 3 ascend and descend through the lifting motor 16, the pulleys move up and down on the left end face and the right end face of the corresponding limiting blocks, and displacement cannot be generated when the front frame and the rear frame ascend and descend.

Referring to fig. 1 and 3, in the present embodiment, each of the two-walking steering mechanisms includes two walking seats and a fixing plate 23 that is horizontally and fixedly mounted above the vehicle body along the width direction of the vehicle body 1, scroll rod mounting blocks are vertically mounted on the lower surface of the fixing plate along the length direction in a bilateral symmetry manner, scroll rod holes are formed in the two scroll rod mounting blocks in a one-to-one correspondence manner, second scroll rods 24 are rotatably connected in the scroll rod holes, and scroll teeth are arranged at the left and right ends of the second scroll rods 24; the walking seat is of a rectangular shell-shaped structure formed by surrounding four vertical plates 22 and a top plate 25, a walking wheel 26 and a walking motor 27 are rotatably mounted in the walking seat, the peripheral surface of the walking wheel is in contact with the ground, and an output shaft of the walking motor 27 is in driving connection with a rotating shaft of the walking wheel 26 through a gear set so as to drive the walking to rotate; a turbine shaft is arranged between each top plate 25 and the fixing plate 23, wherein one end of each turbine shaft is fixedly connected with the corresponding top plate 25, the other end of each turbine shaft is rotatably arranged on the fixing plate 23 through a turbine shaft mounting block, a second turbine 28 is fixedly arranged on each turbine shaft, and the second turbine 28 is meshed with the turbine teeth on the second worm 24; the fixed plate 23 is further provided with a steering motor 29, and an output shaft of the steering motor 29 is in driving connection with the second scroll bar 24 through a driving belt 30 so as to drive the two travelling pedestals to rotate in the same direction. The two scroll bar mounting blocks are bearing seats.

Thus, the travelling wheels 26 and the travelling motor 27 are arranged in the travelling seat, and the travelling motor 27 drives the travelling wheels 26 to rotate through the gear set, so that the AGV trolley is driven to move forwards and backwards; the steering motor 29 transmits power to the second worm 24 and the second turbine 28 through the transmission belt 30, and then the second turbine 28 drives the traveling seats to rotate so as to drive the two traveling seats to rotate in the same direction, thereby realizing steering of the AGV.

In specific implementation, in order to make the running wheels 26 better contact with the ground and keep the running stability of the AGV trolley when dealing with uneven road surfaces, damping mechanisms can be symmetrically arranged between the vertical plate 22 and the top plate 25 of each running seat left and right to increase the running stability of the AGV trolley. Damping mechanism in this scheme is spring damper 31 to make AGV dolly travel in-process can deal with the vibration and the swing that the road surface of undulation is uneven produced, keep the stationarity of AGV dolly travel in-process.

In the specific embodiment, the support rods are horizontally and symmetrically arranged on the left and right sides of the inner wall of the front frame mounting area along the length direction of the vehicle body so as to limit the front frame 2 to keep a certain distance from the ground, save the energy consumption of the AGV trolley and avoid the separation of the front frame 2 from the vehicle body 1.

Finally, it is noted that the above embodiments are merely intended to illustrate the technical solution of the present invention and not to limit the same, and although the present invention has been described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein. All obvious changes which are introduced by the technical solution of the invention are still within the protective scope of the invention.

Claims

1. A parking method based on AGV trolley transfer vehicles is characterized in that waiting parking positions for the vehicles to be parked are arranged at an entrance of a parking lot, and taking positions for the vehicles to be taken are arranged at an exit of the parking lot;

the parking process is as follows:

5) The AGV trolley carries the vehicle to be parked to reach the entrance of the parking space, then the angle and the direction of the vehicle entering the parking space are adjusted through the walking steering mechanism according to the sensor on the parking space, and the vehicle stops running when the front end of the vehicle body of the AGV trolley is in contact with the stop block on the parking space; the two lifting mechanisms respectively drive the corresponding front frame or the corresponding rear frame to descend so that the wheels of the vehicle to be parked fall to the ground, and all the clamping arms are retracted to a vertical state of waiting for parking;

6) The AGV drives away from the parking space and goes to a specified position, wherein the specified position comprises a waiting position for executing the next parking task, and the parking space with the parked car is used for executing the car taking task or waiting for a task instruction in a waiting area;

the vehicle taking process comprises the following steps:

3) The AGV trolley translation device drives the moving frame to move to a set position in the direction of the front frame, the clamping arms, close to the front frame, in each group of clamping arms on the rear frame rotate by 90 degrees and extend out of the rear frame to be in a transverse state, the translation device drives the moving frame to move away from the front frame and approach to the rear wheel of the vehicle after the clamping arms in each group of clamping arms on the rear frame are in the transverse state, when the clamping arms in the transverse state of the rear frame are in contact with the rear wheel, the translation device stops moving, the other clamping arm in each group of clamping arms on the rear frame rotates by 90 degrees and extends out of the clamping arms to be in the transverse state, and in the transverse state, the distance between the two groups of clamping arms of the rear frame is smaller than the diameter of the wheel; in the process that the rear frame clamping arm clamps the rear wheel, the front frame lifting mechanism starts to lift the front frame under the driving of the lifting motor, and stops lifting and maintains the front frame at a set height after the front frame is lifted to the set height; after the rear frame clamping arm clamps the rear wheel in place and the front frame is lifted in place, the rear frame lifting mechanism starts to lift the rear frame under the driving of the lifting motor, and stops lifting and maintains the rear frame at a set height after the rear frame is lifted to the set height;

6) The AGV trolley drives away from the parking space and goes to a designated position, wherein the designated position comprises a waiting position for executing the next parking task, and the parking space with the parked car is used for executing the car taking task or waiting for a task instruction in a waiting area;

the front clamping device and the rear clamping device respectively comprise two clamping arm motors and two horizontal first scroll rods which are arranged at intervals front and back along the width direction of the vehicle body, vortex teeth are arranged at two ends of each first scroll rod, clamping arms which are used for clamping wheels and are in a horizontal plate shape are correspondingly arranged above two ends of each first scroll rod respectively, a clamping arm shaft is fixedly arranged at one end of each clamping arm, penetrates through the corresponding front vehicle frame or the corresponding rear vehicle frame and is rotatably connected with the corresponding front vehicle frame or the corresponding rear vehicle frame, a first turbine is connected to the lower end of each clamping arm shaft through a key, and the first turbine is meshed with the vortex teeth; shaft sleeves for the first scroll rods to horizontally penetrate are correspondingly arranged on the inner side wall of the front frame mounting area and the inner side wall of the movable frame respectively, and the first scroll rods are rotatably connected with the shaft sleeves; the two clamping arm motors are respectively and fixedly arranged on the corresponding front frame and the corresponding rear frame, output shafts of the two clamping arm motors are respectively in driving connection with the corresponding first scroll bars through a bevel gear set, so that the front clamping arm and the rear clamping arm which correspond to the front frame and the rear frame are unfolded outwards towards the vehicle body, the front clamping arm and the rear clamping arm are matched at intervals to clamp the wheel, and the distance between the two clamping arms in each group of clamping arms is smaller than the wheel diameter of the wheel;

the two walking steering mechanisms respectively comprise two walking seats and a fixing plate which is horizontally and fixedly installed along the width direction of the vehicle body and positioned above the vehicle body, scroll rod installation blocks are vertically installed on the lower surface of the fixing plate in a bilateral symmetry mode along the length direction, scroll rod holes are formed in the two scroll rod installation blocks in a one-to-one correspondence mode, second scroll rods are rotatably connected in the scroll rod holes, and scroll teeth are arranged at the left end and the right end of each second scroll rod; the walking seat is of a rectangular shell structure formed by surrounding four vertical plates and a top plate, a walking wheel and a walking motor are rotatably arranged in the walking seat and fixedly arranged in the walking seat, the peripheral surface of the walking wheel is in contact with the ground, and an output shaft of the walking motor is in driving connection with a rotating shaft of the walking wheel through a gear set so as to drive the walking to rotate; a turbine shaft is arranged between each top plate and the fixing plate, one end of each turbine shaft is fixedly connected with the corresponding top plate, the other end of each turbine shaft is rotatably arranged on the fixing plate through a turbine shaft mounting block, a second turbine is fixedly arranged on each turbine shaft, and the second turbine is meshed with the turbine teeth on the second worm rod; a steering motor is further mounted on the fixing plate, and an output shaft of the steering motor is in driving connection with the second scroll bar through a transmission belt so as to drive the two walking seats to rotate in the same direction;

damping mechanisms are symmetrically arranged between the vertical plate and the top plate of each walking seat in a left-right mode, so that each walking wheel can be in better contact with the ground.

2. The parking and taking method based on the AGV trolley transferring vehicle is characterized in that the translation device comprises a translation motor and support plates which are bilaterally symmetrical and horizontally arranged along the length direction of the vehicle body, the support plates are fixedly arranged below the vehicle body, sliding grooves are formed in the upper surfaces of the two support plates along the length direction of the support plates and are located on the inner side of the vehicle body, first strip-shaped teeth are horizontally arranged on the upper surface of one support plate and located on one side of the sliding grooves, the translation motor is fixedly arranged on the moving frame, rollers matched with the sliding grooves are arranged on the moving frame, and gears meshed with the first strip-shaped teeth are arranged on an output shaft of the translation motor so as to drive the moving frame to move back and forth along the length direction of the vehicle body.

3. The method for parking and taking off a AGV trolley transfer vehicle based on claim 2, wherein after all the clamping arms are unfolded, a downwards inclined turnover plate is arranged towards the side of the tire to be clamped, and the turnover plate is rotatably connected with the corresponding clamping arms; a sensor is arranged on one of the left and right groups of clamping arms of the rear clamping device, which is close to the front frame, a signal trigger block is fixedly arranged on the end surface of the turnover plate, which is close to the sensor, the output of the sensor is connected with a controller, the controller is connected with the translation motor, when the signal trigger block is aligned with the sensor in the turnover process of the turnover plate, the translation of the rear frame is in place, and the controller controls the translation motor to stop working; a return spring is arranged between the back of the turnover plate and the clamping arm, and the lower end of the turnover plate slantly faces downwards to the direction of the wheel to be clamped in a holding mode in a natural state.

4. The parking and taking method based on the AGV trolley transferring vehicle is characterized in that lifting mechanisms on a front trolley frame mounting area and the front trolley frame, and on a moving frame and a rear trolley frame respectively comprise a lifting motor and a transmission shaft horizontally arranged along the length direction of a vehicle body, two ends of the transmission shaft respectively penetrate through the corresponding front trolley frame and the corresponding rear trolley frame and are respectively in rotary connection with the corresponding front trolley frame and the corresponding rear trolley frame, and gears are fixedly mounted at two ends of the transmission shaft; the inner side wall of the front frame mounting area and the inner side wall of the movable frame are respectively provided with a vertically mounted second strip-shaped tooth matched with the gears at the two ends of the corresponding transmission shaft, and the two second strip-shaped teeth are meshed with the gears at the two ends of the transmission shaft; the lifting motor is respectively fixedly installed on the front frame and the rear frame through motor supports, and an output shaft of the lifting motor is in driving connection with the transmission shaft through a transmission belt or a bevel gear set so as to respectively lift and lower the front frame and the rear frame.

5. The method as claimed in claim 4, wherein the inner side walls of the movable frame and the front frame mounting region are respectively provided with a plurality of limiting blocks in a bilateral symmetry manner, and the front frame and the rear frame are respectively provided with pulleys which are fitted with the left and right end faces of the limiting blocks in a rotating manner.