WO2024159689A1 - Lifting/lowering mechanism - Google Patents

Abstract

A lifting/lowering mechanism, comprising a lifting/lowering shaft (1). The lifting/lowering shaft can be driven by a lifting/lowering driving member to rotate along the axis of the lifting/lowering shaft. At least one winding wheel (2) rotating synchronously with the lifting/lowering shaft is sleeved on the lifting/lowering shaft, and a conductive belt (3) is wound on each winding wheel. One end of the conductive belt is fixed on the winding wheel, and a cable in the conductive belt is connected to a rotor of a conductive slip ring (4) at the end portion of the lifting/lowering shaft. The rotor of the conductive slip ring synchronously rotates with the lifting/lowering shaft, and a wire on a stator of the conductive slip ring is connected to an external wire. A guide channel (24) is provided on the winding wheel; since the guide channel is located between an outer ring surface (211) and a shaft hole (23), and the end portion of the conductive belt is fixed in the guide channel, a pressing piece for fixing the conductive belt does not protrude out of the outer ring surface, thereby ensuring that the outer ring surface is smooth and has no protrusions. Therefore, when the conductive belt is wound on the outer ring surface, no protrusions exist, the conductive belt can be tightly attached to the outer ring surface of the winding wheel, and the positioning accuracy of lifting/lowering motion of the conductive belt is improved.

Description

A lifting mechanism Technical Field

The present invention relates to the technical field of automatic material transmission in semiconductor manufacturing industry, and in particular to a lifting mechanism.

Background Art

The transfer of wafer boxes (FOUP) is a routine step in the semiconductor processing industry, and usually adopts the automatic material handling system (AMHS Automatic Material Handling System). The core part of the automatic material handling system is the overhead crane (OHT, Overhead Hoist Transport), which automatically grabs the wafer box from one platform (Loadport) and moves it to another platform. No human intervention is required throughout the process, avoiding human pollution to the clean room, and greatly improving productivity. After grabbing the wafer box, the overhead crane needs to lift the wafer box into the inside of the overhead crane, and position and clamp it. Therefore, the lifting mechanism is an important component of the overhead crane.

The lifting mechanism lifts the wafer box through a lifting belt. One end of the lifting belt is connected to the gripping mechanism that grabs the wafer box, and the other end is fixed to the winding wheel. The winding wheel is fixed to the lifting shaft. When the lifting shaft rotates, the lifting belt is wound or unwound on the winding wheel to lift the wafer box. At present, the lifting belt mainly adopts the form of a "conductive belt". The lifting belt includes a belt body and a wire inside the belt body. The belt body is used to bear the weight of the gripping mechanism and the wafer box. The wire is used to power the gripping mechanism and communicate, and the wire is connected by a conductive slip ring.

However, in the existing lifting mechanism, since the conductive belt needs to be fixed on the winding wheel and the wire needs to pass through the winding wheel, the winding wheel is usually set to be split, and the conductive belt is directly wound on the winding wheel after being compressed. The conductive belt is tightly pressed on the winding wheel, so a "bulge" will be formed at the pressing point. The bulge will seriously affect the winding accuracy of the conductive belt during the lifting movement, causing the grabbing mechanism below to not operate smoothly. At the same time, the rotor end of the conductive slip ring needs to rotate synchronously with the lifting shaft, and the conductive slip ring is a precise and fragile component. The rigid connection between the lifting shaft and the rotor end will damage the conductive slip ring. Therefore, rubber rings are basically used to flexibly connect the rotor end of the conductive slip ring and the lifting shaft, but the fixing effect of the rubber ring is not good. There is a speed difference between the rotor end of the conductive slip ring and the lifting shaft, which will pull the wire and seriously affect the life of the wire.

Summary of the invention

In order to overcome the above-mentioned disadvantages, the object of the present invention is to provide a lifting mechanism, which greatly improves the stability and accuracy of lifting.

In order to achieve the above purpose, the technical solution adopted by the present invention is: a lifting mechanism, a lifting shaft, the lifting shaft can rotate along its own axis. A winding wheel, the winding wheel is provided with at least one and is sleeved on the lifting shaft and rotates synchronously with the lifting shaft, each of the winding wheels includes an outer ring surface, an axial hole, channel one, channel two and a guide channel, the axial hole is for the lifting shaft to pass through, the guide channel is located between the axial hole and the outer ring surface and is arranged around the axial hole, the guide channel is connected to channel one passing through the outer ring surface, and the channel two is arranged between the guide channel and the axial hole and connects the two. A conductive slip ring, the conductive slip ring is arranged at the end of the lifting shaft, and the rotor end of the conductive slip ring is fixed to the lifting shaft and rotates synchronously.

The beneficial effects of the present invention are as follows: a guide channel is arranged on the winding wheel. Since the guide channel is located between the outer ring surface and the shaft hole, it is convenient to fix the lifting belt. The pressing sheet for fixing the lifting belt will not protrude from the outer ring surface, ensuring that the outer ring surface is smooth and has no protrusions. Therefore, when the lifting belt is wound on the outer ring surface, there will be no bulges, and the lifting belt can be tightly attached to the outer ring surface of the winding wheel. The positioning accuracy of the lifting belt's lifting motion is ensured.

Furthermore, it also includes a lifting belt, which is wound on the outer ring surface, and the lifting belt is passed through the inner end of the guide channel and fixed in the guide channel. The lifting belt is a conductive belt, and the cable in the conductive belt enters the shaft hole from channel 2, and passes through the winding wheel and the lifting shaft to connect with the rotor end. The guide channel and channel 2 facilitate the routing of the cables and effectively protect the cables.

Furthermore, the channel 1 is arranged along the radial direction of the winding wheel, and the side of the channel 1 close to the outer ring surface is the entrance of the conductive belt, and an arc-shaped chamfer is formed between the side wall of the channel 1 at the entrance and the outer ring surface. Because the conductive belt has a certain thickness, if it is directly bent at 90 degrees, the conductive belt cannot be close to the bend, so an arc-shaped chamfer is set to allow the conductive belt to fit tightly at the junction of the outer ring surface and the channel 1, thereby allowing the conductive belt to fit tightly on the outer ring surface of the winding wheel.

Furthermore, the channel 1 has at least one inclined surface or arc surface, and the conductive belt fits on the inclined surface or arc surface to enter the guide channel. The setting of the inclined surface or arc surface forms a structure in which the space of channel 1 gradually increases from its entrance, that is, the cross-sectional area of channel 1 gradually increases from close to the outer ring surface to far away from the outer ring surface. On the one hand, this structure leaves enough space for the conductive belt to enter the guide channel from channel 1, and on the other hand, the inclined surface or arc surface guides the conductive belt to achieve a smooth transition from channel 1 to the entrance of the guide channel. The conductive belt fits tightly on the inclined surface or arc surface to avoid bulging of the conductive belt at the turning point, ensuring that the conductive belt is also flat in channel 1.

Furthermore, the guide channel surrounds the entire shaft hole or surrounds a portion of the shaft hole.

When the guide channel surrounds the entire shaft hole, the guide channel is a structure connected end to end. At this time, the center lines of channel 2 and channel 1 coincide, and channel 2 and channel 1 are opened along the same radial direction. When the channel surrounds part of the axial hole, that is, there is a gap between the inlet and outlet of the guide channel, the guide channel is not connected from end to end, and channel 2 is set at the outlet of the guide channel.

Furthermore, the winding wheel includes two end faces located on both sides of the outer ring surface, each of the end faces is provided with a groove along the axial direction, the grooves are arranged at intervals along the circumferential direction on the corresponding end faces, the grooves on the two end faces are arranged alternately, and the groove on one end face can connect to two adjacent grooves on the other end face.

The grooves on the two end faces are staggered, and only a large amount of hollowing out of the internal material of the winding wheel is required, which ensures that a guide channel can be processed to form a head-to-tail structure. Even if a guide channel is set between the outer ring surface and the shaft hole, the winding wheel is still a whole, ensuring the feasibility of mechanical processing of the component. At the same time, the overall structure ensures the strength and rigidity of the winding wheel. Furthermore, the staggered grooves limit the conductive belt between the two end faces, and will not slip out of the winding wheel from any end face, which limits the axial position of the conductive belt in the guide channel.

Furthermore, the winding wheel includes a winding portion and a fixing portion located on both sides of the winding portion along the axial direction, the winding portion and the fixing portion are coaxial cylindrical structures, and the diameter of the winding portion is larger than the diameter of the fixing portion, the side surface of the winding portion is an outer annular surface, and the two surfaces of the fixing portions away from the winding portion are end surfaces with grooves, and the grooves extend to the winding portion.

Specifically, the end of the conductive belt is fixed in the guide channel by a pressing sheet, a notch is radially provided on the side wall of the fixing portion and is in communication with the guide channel, a bolt hole is provided on the fixing portion and corresponds to the notch, and the pressing sheet is fixed to the fixing portion by a bolt threadedly connected to the bolt hole. After the pressing sheet presses the conductive belt, the bolt is placed in the notch and tightened, and the pressing sheet is fixed to the fixing portion by the bolt passing through the bolt hole, that is, the conductive belt is fixed to the fixing portion. The ends of the electric belt are fixed in the guide channel. The notch facilitates the turning of the bolts and provides convenience for installation and removal.

Furthermore, each of the winding wheels is fixed with baffles located on both sides of the outer ring surface, the baffles are annular structures and are coaxially arranged with the winding wheel, the baffles extend out of the winding wheel, and a cavity for winding the conductive belt is defined between the two baffles and the outer ring surface. The baffles define the axial position of the conductive belt on the outer ring surface, reducing the axial deviation of the conductive belt during the winding process.

Furthermore, an inclined wedge-shaped surface is provided on the side of the baffle plate facing the outer ring surface, and the wedge-shaped surface is provided at the portion of the baffle plate extending out of the winding wheel, and each of the wedge-shaped surfaces expands outward from the side close to the outer ring surface to the side away from the outer ring surface. The wedge-shaped surface allows the cavity to form an expansion structure, thereby reducing damage to the side of the conductive belt and extending the service life of the conductive belt.

Furthermore, the baffle is a split structure, including at least two split parts, each of which is detachably connected to the winding wheel, and the split parts can be spliced to form a baffle with an annular structure. Only after the baffle is removed can the pressing plate be removed from the guide channel and the conductive belt be taken out. The baffle with a split structure can be directly removed from the winding wheel without moving other parts on the lifting shaft, such as the bearing seat or the conductive slip ring, to facilitate the replacement of the conductive belt.

Furthermore, a wiring groove is provided along the axis of the side wall of the lifting shaft. When the lifting shaft is keyed to the winding wheel, the position of the wiring groove corresponds to channel 2, and the cable passing through channel 2 is connected to the rotor end of the conductive slip ring along the wiring groove. The wire groove guides the cable and plays a fixing role. The wiring groove is provided on the side wall of the lifting shaft without a hole in the center, which is convenient for later maintenance and cable threading.

Furthermore, the rotor end is connected to the lifting shaft through a connecting assembly. The assembly includes a connecting piece and a fixing piece, wherein the connecting piece is fixed to the end of the lifting shaft, and the fixing piece is used to connect the rotor end with the connecting piece and realize synchronous rotation of the rotor end and the connecting piece. The fixing piece is used to flexibly connect the rotor end with the connecting piece.

Furthermore, the connecting member includes a circular connecting plate and an annular vertical wall extending along the side of the connecting plate, the connecting plate is fixed to the end of the lifting shaft, and a plug-in cavity for the rotor end to be inserted is defined between the connecting plate and the annular vertical wall, and the rotor end is suspended and plugged into the plug-in cavity; the part of the fixing member located in the plug-in cavity is tensioned into a limiting plane that fits the plane of the rotor end, and the rotor end is located in the limiting cavity defined by the limiting plane and rotates synchronously with the limiting plane under the push of the limiting plane, and the end of the fixing member is fixed on the outer wall of the annular vertical wall through the limiting groove. The rotor end is a non-circular structure, so a fixing member is used to penetrate and form a limiting cavity that is flexibly connected to the rotor end. When the fixing member and the connecting member rotate synchronously, the rotor end is driven to rotate synchronously.

Furthermore, the fixing member is a belt body made of metal or plastic, and a groove is provided on the annular vertical wall for the belt body end to pass through. The belt body is thin and easy to bend.

Furthermore, each of the conductive belts corresponds to a steering wheel, and the conductive belt extending horizontally on the winding wheel turns to the vertical direction after passing through the steering wheel. A pair of follower wheels with adjustable spacing are also provided under each steering wheel. The pair of follower wheels are respectively located on both sides of the conductive belt and abut against the side edges of the conductive belt. The conductive belt will move axially along the lifting shaft during the lifting movement. If the axial limit is only provided by the baffle plate, the side edge of the conductive belt will generate sliding friction with the baffle plate, affecting the life of the belt and the cleanliness of the purification room. Therefore, a pair of follower wheels are added. When the conductive belt is running, the follower wheels rotate along with the lifting and lowering of the conductive belt, which not only constrains the axial position of the conductive belt, but also sets the conductive belt and the baffle plate together. The sliding friction between the plates or flanges is converted into rolling friction between the conductive belt and the follower wheel, which greatly reduces the wear of the conductive belt.

Furthermore, the follower wheel is provided with a guide ring groove along the circumferential direction for the side edge of the conductive belt to be embedded, and the side edge of the conductive belt is always located in the guide ring groove.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a bottom view of an embodiment of the present invention;

Fig. 2 is a cross-sectional view along line A-A in Fig. 1 and a partial enlarged view thereof;

FIG3 is a three-dimensional diagram of an embodiment of the present invention after the substrate is removed;

FIG4 is a perspective view of a winding wheel in an embodiment of the present invention;

FIG5 is a three-dimensional view of the winding wheel from another angle in an embodiment of the present invention;

FIG6 is a cross-sectional view of the winding wheel along the center plane in an embodiment of the present invention;

FIG7 is a front view of a winding wheel in an embodiment of the present invention;

FIG8 is a three-dimensional diagram of a connection state between a connection assembly and a conductive slip ring in an embodiment of the present invention;

FIG9 is a cross-sectional view of a connection state between a connection assembly and a conductive slip ring in an embodiment of the present invention;

FIG10 is a schematic diagram of the three-dimensional structure of a connecting member in an embodiment of the present invention;

FIG11 is a schematic diagram of the three-dimensional structure of the lifting shaft in an embodiment of the present invention;

FIG12 is a schematic diagram of the three-dimensional structure of a baffle in an embodiment of the present invention;

FIG. 13 is a schematic diagram showing the connection state of a pair of follower wheels and a conductive belt in an embodiment of the present invention.

In the figure:

1. Lifting shaft; 1a. Wire groove; 2. Winding wheel; 21. Winding part; 211. Outer ring Surface; 22, fixing part; 221, end face; 224, notch; 225, bolt hole; 23, shaft hole; 24, guide channel; 241, groove one; 242, groove two; 25, channel one; 251, chamfer; 252, inclined surface; 26, channel two; 3, conductive belt; 4, conductive slip ring; 41, rotor end; 5, baffle; 51, wedge surface; 6, connecting assembly; 61, connecting piece; 611, connecting plate; 6111, wire hole; 6112, connecting hole; 612, annular wall; 6121, make way groove; 62, fixing piece; 621, limiting plane; 7, base plate; 71, bearing seat; 72, mounting bracket; 8, steering wheel; 9, follower wheel; 91, guide ring groove; 10, transition wheel; 11, synchronous pulley; 12, lifting shaft connecting piece.

DETAILED DESCRIPTION

The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

Referring to Figures 1 to 3, a lifting mechanism of the present invention includes a lifting shaft 1, which can rotate along its own axis under the drive of a lifting drive. The lifting shaft 1 is sleeved with at least one winding wheel 2 that rotates synchronously with it, and each winding wheel 2 is wound with a lifting belt. In this embodiment, the lifting belt is a conductive belt 3. One end of the conductive belt 3 is fixed to the winding wheel 2, and the cable in the conductive belt 3 is connected to the rotor end 41 of the conductive slip ring 4 at the end of the lifting shaft 1. The rotor end 41 of the conductive slip ring 4 rotates synchronously with the lifting shaft 1, and the wires on the stator end of the conductive slip ring 4 are connected to the external wires.

When the lifting drive member drives the lifting shaft 1 to rotate, the winding wheel 2 rotates synchronously, thereby driving the conductive belt 3 to be wound and unwound, thereby realizing the lifting and lowering of the clamping mechanism (not shown in the figure) connected to the other end of the conductive belt 3.

As shown in Figures 4 to 6, the winding wheel 2 includes an outer ring surface 211 for the conductive belt 3 to be wound around and an axial hole 23 for the lifting shaft 1 to pass through. The axial hole 23 is opened along the axial direction of the winding wheel 2 and is coaxially arranged with the outer ring surface 211. The winding wheel 2 is also provided with a guide channel 24 located between the axial hole 23 and the outer ring surface 211 and arranged around the axial hole 23. The conductive belt 3 is passed through the guide channel 24, and the end of the conductive belt 3 is fixed in the guide channel 24. The guide channel 24 is connected to the channel 1 25 that passes through the outer ring surface 211, that is, the channel 1 25 connects the outer ring surface 211 and the guide channel 24, and a channel 2 26 that connects the guide channel 24 and the axial hole 23 is provided between the guide channel 24 and the axial hole 23.

A guide channel 24 is provided on the winding wheel 2. Since the guide channel 24 is located between the outer annular surface 211 and the shaft hole 23, the end of the conductive belt 3 is fixed in the guide channel 24, and the pressing sheet for fixing the conductive belt 3 does not protrude from the outer annular surface 211, ensuring that the outer annular surface 211 is smooth and has no protrusions. Therefore, when the conductive belt 3 is wound on the outer annular surface 211, there will be no bulges, and the conductive belt 3 can fit tightly on the outer annular surface 211 of the winding wheel 2, ensuring the positioning accuracy of the lifting and lowering movement of the conductive belt 3. Even if the lifting belt is not the conductive belt 3, but other conventional belts, the winding wheel 2 structure in this application is adopted, and the end of the lifting belt can be fixed in the guide channel 24 through the provision of the guide channel 24, which can ensure that there are no protrusions on the outer annular surface 211 of the lifting belt, thereby improving the lifting accuracy.

As for the conductive belt 3, the conductive belt 3 enters the guide channel 24 from the channel 1 25, moves along the guide channel 24 and fixes its end in the guide channel 24, the cable in the conductive belt 3 continues to move along the guide channel 24 and enters the shaft hole 23 from the channel 2 26, and the cable passes through the winding wheel 2 between the winding wheel 2 and the lifting shaft 1. The cooperation between the guide channel 24 and the channel 2 26 facilitates the installation of the cable of the conductive belt 3.

In one embodiment, referring to FIGS. 4 and 7 , the channel 1 25 is arranged along the radial direction of the winding wheel 2, and the side of the channel 1 25 close to the outer annular surface is the inlet of the conductive belt 3. An arc-shaped chamfer 251 is formed between the side wall of the channel 1 25 at the inlet and the outer annular surface 211. The chamfer 251 allows the conductive belt 3 to fit tightly at the junction of the outer annular surface 211 and the channel 1 25. Because the conductive belt 3 has a certain thickness, if it is bent directly at 90 degrees, the conductive belt 3 cannot fit close to the bend, so a chamfer 251 is provided so that the conductive belt 3 can fit tightly on the outer annular surface 211 of the winding wheel 2.

The entrance directions of the channel 1 25 and the guide channel 24 are different. After the conductive belt 3 enters the channel 1 25, it will turn and enter the guide channel 24. Therefore, as shown in Figures 6 and 7, the channel 1 25 has a slope 252 or an arc surface, and the conductive belt 3 fits on the slope 252 or the arc surface to enter the guide channel 24. The setting of the slope 252 or the arc surface forms a structure in which the space of the channel 1 25 gradually increases from its entrance, that is, the cross-sectional area of the channel 1 25 gradually increases from the outer ring surface 211 to the outer ring surface 211. On the one hand, this structure leaves enough space for the conductive belt 3 to enter the guide channel 24 from the channel 1 25. On the other hand, the slope 252 or the arc surface guides the conductive belt 3 to achieve a smooth transition from the channel 1 25 to the entrance of the guide channel 24. The conductive belt 3 fits tightly on the slope 252 or the arc surface to avoid the conductive belt 3 from bulging at the turning point, and ensure that the conductive belt 3 is also flat in the channel 1 25.

6 and 7 , the channel 1 25 has an inclined surface 252 , which is inclined from the entrance of the channel 1 25 toward the entrance of the guide channel 24 along the direction of the conductive belt 3 . The arc surface is a convex arc protruding toward the channel 1 25 .

Of course, in one embodiment, the channel 1 25 may also have two inclined surfaces 252 or curved surfaces. The two inclined surfaces 252 or curved surfaces are symmetrically arranged relative to the axis of the channel 1, and the channel 1 25 can still form a structure in which the space gradually increases from its entrance, and the conductive belt 3 fits on one of the inclined surfaces 252 or curved surfaces to enter the guide channel 24. It is sufficient to ensure that the channel 1 25 has at least one inclined surface 252 or curved surface that guides the conductive belt 3.

In one embodiment, as shown in FIG. 6 , the guide channel 24 surrounds the entire shaft hole 23, that is, the guide channel 24 is a structure connected end to end. The direction of the arrow in FIG. 6 is the direction of the cable in the conductive belt 3, and the conductive belt 3 is also along the direction of the arrow in FIG. 6 , but the conductive belt 3 does not need to be inserted into the entire guide channel 24. The conductive belt 3 is fixed at a position close to the second channel 26, and the cable continues to be inserted along the guide channel 24 until the cable passes through the entire guide channel 24, reaches the position of the second channel 26, and enters the second channel 26. At this time, the center lines of the second channel 26 and the first channel 25 coincide, and the second channel 26 and the first channel 25 are opened along the same radial direction.

In this embodiment, the cross section of the guide channel 24 along the radial direction is a circular ring structure, and the circular ring structure is coaxial with the outer ring surface 211. The guide channel 24 with a circular ring structure is convenient for the insertion of the conductive belt 3. Of course, in some embodiments, the cross section of the guide channel 24 along the radial direction is a polygonal structure, and the connection between adjacent sides of the polygonal structure is rounded. Considering the convenience of processing and the insertion of the conductive belt 3, the guide channel 24 generally uses a circular ring structure and a quadrilateral structure, as shown in Figure 6. In this embodiment, the guide channel 24 is a quadrilateral structure.

In one embodiment, the guide channel 24 surrounds part of the shaft hole 23, that is, there is a gap between the entrance and exit of the guide channel 24, and the guide channels 24 are not connected at the beginning and the end. The second channel 26 is arranged at the exit of the guide channel 24. At this time, the conductive belt enters from the entrance of the first channel 25, passes along the guide channel 24, and is fixed between the entrance and exit of the guide channel 24. The cable continues The cable continues to pass along the guide channel 24 until it enters the second channel 26 .

In this embodiment, the cross section of the guide channel 24 along the radial direction is an arc-shaped structure, and the arc-shaped structure is a circular arc, and the center of the circular arc coincides with the center of the outer annular surface 211 .

Of course, when the guide channel 24 surrounds the entire shaft hole 23, the distance of the guide channel 24 is large, and the contact area between the conductive belt 3 and the guide channel 24 will also increase, so the connection between the conductive belt 3 and the winding wheel 2 is more stable.

As shown in Figures 4 and 5, the winding wheel 2 includes two end faces 221, which are respectively located on both sides of the outer ring surface 211. Each end face 221 is provided with slots arranged at intervals along the axial direction. The slots on one end face 221 will not penetrate the other end face 221, and the slots are arranged at intervals along the circumferential direction on the corresponding end face 221. The slots on the two end faces 221 are arranged alternately, and the slots on one end face 221 can be connected to the adjacent slots on the other end face 221.

The two end faces 221 are respectively the first end face and the second end face. As shown in FIG5 , the first end face is provided with a groove 1 241, and as shown in FIG5 , the second end face is provided with a groove 242. The grooves 1 241 are arranged at intervals, and the grooves 242 are arranged at intervals, and the grooves 242 and the grooves 1 241 are staggered, that is, the grooves 242 are located between two adjacent grooves 1 241. As shown in FIG7 , the two ends of the groove 242 are connected to the ends of the two adjacent grooves 1 241, that is, the two adjacent grooves 1 241 are connected through the groove 242. The grooves 1 241 and the grooves 2 242 cooperate to form a guide channel 24 on the center plane of the winding wheel 2.

The grooves on the two end faces 221 are staggered, and only a large amount of hollowing out of the inner material of the winding wheel 2 is required, so that the guide channel 24 with an end-to-end structure can be processed. A guide channel 24 is provided between the outer ring surface 211 and the shaft hole 23, and the winding wheel 2 is still an integral body, which ensures the feasibility of mechanical processing of the component. At the same time, the integral structure ensures the strength and rigidity of the winding wheel 2. Furthermore, the staggered grooves limit the conductive belt 3 between the two end surfaces 221, and will not slip out of the winding wheel 2 from any end surface 221, thereby limiting the axial position of the conductive belt 3 in the guide channel 24.

As shown in FIG. 5 , the winding wheel 2 includes a winding portion 21 and fixed portions 22 located on both axial sides of the winding portion 21. The winding portion 21 and the fixed portion 22 are coaxially arranged cylindrical structures, and the diameter of the winding portion 21 is larger than the diameter of the fixed portion 22. The axial hole passes through the winding portion 21 and the two fixed portions 22. The side surface of the winding portion 21 is the outer annular surface 211 for the conductive belt 3 to be wound, and the two surfaces of the two fixed portions 22 away from the winding portion 21 are the end surfaces 221 with the grooves opened. The grooves are opened on the fixed portion 22 and can extend into the winding portion 21. The conductive belt 3 passes through the guide channel 24 in the winding portion 21.

The end of the conductive belt 3 is fixed in the guide channel 24 by a pressing sheet, and the pressing sheet is also located in the guide channel 24. The pressing sheet will not protrude from the outer annular surface 211 to avoid affecting the winding of the conductive belt 3. The pressing sheet is fixed in the guide channel 24 by bolts. In order to facilitate the placement of the pressing sheet, as shown in Figures 4 and 5, a notch 224 connected to the guide channel 24 is radially opened on the side walls of the two fixing parts 22, and a bolt hole 225 corresponding to the notch 224 is opened on the fixing part 22. The pressing sheet is placed at a position corresponding to the notch 224. At this time, the pressing sheet is fixed to the fixing part 22 by a bolt passing through the bolt hole 225. The notch 224 facilitates the fixing and removal of the bolt to fix the end of the conductive belt 3 in the guide channel 24. The pressing sheet is located where the groove 1 241 and the groove 2 242 are connected. The pressing sheet is placed at a position corresponding to the notch 224. The pressing sheet placed at the notch 224 can extend from the groove 1 241 to the groove 2 242, fix the conductive belt 3 from both sides.

The winding wheel 2 and the lifting shaft 1 are key-connected so that they can rotate synchronously. The lifting shaft 1 is provided with a flat key protruding from its surface, and the winding wheel 2 is provided with a keyway connected to the shaft hole and for the flat key to be embedded.

In one embodiment, during the rotation of the winding wheel 2, in order to ensure that the conductive belt 3 is always located on the outer annular surface 211 and does not produce axial displacement during the winding process, as shown in Figure 2, each winding wheel 2 is provided with a baffle 5 fixedly connected thereto on both sides, and the conductive belt 3 wound on the outer annular surface 211 of the winding wheel 2 is located between the two baffles 5.

As shown in FIG. 12 , the baffle 5 is an annular structure, the baffle 5 is coaxial with the winding wheel 2, and the outer diameter of the baffle 5 is larger than the outer diameter of the winding portion 21, ensuring that the baffle 5 protrudes from the outer annular surface 211, and a cavity for winding the conductive belt 3 is defined between the two baffles 5 and the outer annular surface 211. The baffle 5 is sleeved on the fixing portion 22 and connected to the winding portion 21 by bolts.

In order to allow the conductive belt 3 to be wound on the outer annular surface 211, the width of the outer annular surface 211 is not less than the width of the conductive belt 3. In order to improve stability and reduce deviation, the width of the outer annular surface 211 is set to be the same as the width of the conductive belt 3. However, in order to avoid the edge of the baffle 5 from damaging the side of the conductive belt 3, as shown in Figure 12, the baffle 5 is provided with an inclined wedge surface 51 on the side facing the outer annular surface 211. When the two baffles 5 are installed on the winding wheel 2, the wedge surface 51 is located on the opposite surface of the two baffles 5. Each wedge surface 51 expands outward from the side close to the outer annular surface 211 to the side away from the outer annular surface 211. As shown in Figure 2, the wedge surface 51 allows the cavity to form an expanded structure to reduce damage to the side of the conductive belt 3.

When the conductive belt 3 is lifted and lowered, it is easy to contact the baffles on both sides of the winding wheel 2. 5 generates sliding friction, and the side of the conductive belt 3 will be worn after long-term operation, which not only affects the carrying capacity of the conductive belt 3, but also the particles generated by the wear and tear also damage the clean room environment. The setting of the wedge-shaped surface 51 on the baffle 5 reduces the contact between the baffle 5 and the side of the conductive belt 3, reduces the wear of the conductive belt 3, and prolongs the service life of the conductive belt 3.

As shown in Figures 2 and 12, the wedge-shaped surface 51 is provided at the portion of the baffle 5 extending out of the winding wheel 2, and the other positions of the baffle 5 on the side facing the outer annular surface 211 are still flat. Because the wedge-shaped surface 51 is only required at the portion that may contact the conductive belt 3, and the other positions are flat, the flat surface will fit closely with the side of the winding wheel 2, thereby improving the stability of the connection between the two.

In one embodiment, the baffle 5 is a split structure, including at least two split parts, each of which is detachably connected to the winding wheel 2. The split parts can be spliced to form a complete ring-shaped baffle 5. In this embodiment, there are two split parts, namely, split part 1 and split part 2 of a fan-shaped structure. When split part 1 and split part 2 are combined, a ring-shaped baffle 5 is formed. After the conductive belt 3 is fixed on the winding wheel 2, split part 1 and split part 2 are respectively fixed on the winding wheel 2. Of course, the baffle 5 can also be split into 3, 4 or more split parts. It is only necessary for the baffle 5 to be split, but in order to facilitate quick installation, as shown in Figure 12, the split parts are usually set to two.

Only after the baffle 5 is removed can the pressing sheet be removed from the guide channel 24 and the conductive belt 3 be taken out. The baffle 5 of the split structure can be directly removed from the winding wheel 2 without moving other components on the lifting shaft 1, such as the bearing seat 71 or the conductive slip ring 4, to facilitate the replacement of the conductive belt 3. This avoids the need to dismantle the lifting mechanism as a whole when replacing the conductive belt 3, which is convenient for maintenance.

In one embodiment, as shown in FIG. 11 , the side wall of the lifting shaft 1 is opened along the axis. A wiring groove 1a is formed, and the cables passing through the channel 26 are connected to the rotor end 41 of the conductive slip ring 4 along the wiring groove 1a. The wiring groove 1a guides the cables and plays a fixing role. The wiring groove 1a is provided on the side wall of the lifting shaft 1, and there is no groove in the center of the lifting shaft 1, so that the cables can be directly threaded or replaced from the side, which is convenient for later maintenance.

When the lifting shaft 1 is keyed to the winding wheel 2, the position of the wiring groove 1a corresponds to the second channel 26, the second channel 26 is connected to the wiring groove 1a, and the cables passing through the second channel 26 can directly enter the wiring groove 1a.

As shown in Figures 3 and 8, the rotor end 41 of the conductive slip ring 4 is connected to the lifting shaft 1 through the connecting assembly 6, and the rotor end 41 rotates synchronously with the lifting shaft 1. The connecting assembly 6 includes a connecting member 61 and a fixing member 62, the connecting member 61 is fixed to the lifting shaft 1, and the fixing member 62 is used to flexibly connect the rotor end 41 with the connecting member 61, and realize the synchronous rotation of the rotor end 41 and the connecting member 61.

As shown in FIG. 10 , the connecting member 61 is a cylindrical structure with one end open, including a circular connecting plate 611 and an annular vertical wall 612 extending along the side of the connecting plate 611, and the connecting plate 611 is fixed to the end of the lifting shaft 1 by bolts. A plug-in cavity for inserting the rotor end 41 is defined between the connecting plate 611 and the annular vertical wall 612, and the rotor end 41 is suspended and plugged into the plug-in cavity. Because the rotor end 41 cannot be directly connected by rigidity, the rotor end 41 cannot be inserted into the plug-in cavity by interference fit, nor can it be directly fixed by bolts. As shown in FIG. 9 , there is a gap between the rotor end 41 and the annular vertical wall 612, and the rotor end 41 does not directly contact the annular vertical wall 612. The fixing member 62 is located at the gap, and extends out of the plug-in cavity to be fixedly connected to the connecting member 61, and the fixing member 62 is used to drive the rotor end 41 and the connecting member 61 to rotate synchronously.

The rotor end 41 is a non-circular structure, ensuring that the rotor end 41 has a flat surface, see FIG. 9 As shown, the portion of the fixing member 62 located in the insertion cavity is tensioned to form a limiting plane 621 that fits the plane of the rotor end 41. The rotor end 41 is located in the limiting cavity defined by the limiting plane 621. The limiting cavity forms a flexible snap connection with the rotor end 41. The limiting plane 621 pushes the rotor end 41 to rotate synchronously with it. A clearance groove 6121 is provided on the annular vertical wall 612 for the end of the fixing member 62 to pass through. The fixing member 62 is fixed to the outer wall of the annular vertical wall 612.

The fixing member 62 is a belt body made of metal or plastic material, and the belt body is thin and convenient to bend. In the present application, the belt body adopts a steel belt.

In this embodiment, as shown in FIG. 9 , the rotor end 41 has two parallel planes, the two planes are arc-shaped and the gap between the two planes and the annular wall 612 is small (1 mm). The portion of the steel belt in the plug-in cavity forms two parallel limiting planes 621, the limiting planes 621 are in contact with the two mutually parallel surfaces of the rotor end 41, the rotor end 41 is located between the two limiting planes 621, and the end of the steel belt passes through the plug-in slot and is fixed to the connector 61.

In this embodiment, as shown in FIG. 10 , four clearance grooves 6121 are provided, each of which is opened axially along the annular vertical wall 612, and the connecting line of the four clearance grooves 6121 forms a square. The four clearance grooves 6121 are slot 1, slot 2, slot 3 and slot 4 in the circumferential direction of the annular vertical wall 612, as shown in FIG. 9 , and the hollow arrow in the figure is the direction of the steel belt. The steel belt enters the plug-in cavity from slot 1, passes through the plug-in cavity from slot 2, is wound around the outer wall of the annular vertical wall 612 between slots 2 and 3, and then enters the plug-in cavity from slot 3, passes through the plug-in cavity from slot 4, and the two ends of the steel belt overlap on the outer wall of the annular vertical wall 612 between slot 4 and slot 1, and the steel belt is fixed by bolts passing through the overlapped part of its ends.

Of course, two steel belts can also be used, one steel belt enters the plug-in cavity from slot one, passes through the plug-in cavity from slot two, and then the two ends and the connecting piece 61 are fixed by bolts; the other steel belt passes through slot three. Enter the plug-in cavity, pass through the plug-in cavity from slot 4, and then fix the two ends to the connecting piece 61.

The adapter is connected to the lifting shaft 1 by bolts, the rotor end 41 of the conductive slip ring 4 is inserted into the plug-in cavity, and the steel belt passes through four clearance grooves 6121 in sequence, and is fixed to the annular wall 612 by bolts after being wound around the annular wall 612 for one circle. The flexible connection between the rotor end 41 and the lifting shaft 1 is realized, which not only meets the installation requirements of the conductive slip ring 4, but also ensures the synchronization of the rotation of the rotor end 41 and the lifting shaft 1, reduces the speed difference, avoids pulling the cable, and effectively ensures the service life of the conductive slip ring 4.

As shown in FIG. 10 , the connection plate 611 is provided with a wire hole 6111 through which the cable passes, and the position of the wire hole 6111 corresponds to the position of the wire groove 1a. Because the wire groove 1a is provided on the side wall of the lifting shaft 1, the wire hole 6111 is also eccentrically arranged. The connection plate 611 is also provided with a connection hole 6112 through which the bolt passes, and the connection plate 611 is fixed to the lifting shaft 1 by the bolt passing through the connection hole 6112.

As shown in FIG. 3 , three winding wheels 2 are provided, which are respectively located in the middle and at both ends of the lifting shaft 1 , so that three conductive belts 3 are used to lift and lower the grabbing device, thereby improving the lifting stability of the grabbing device.

In one embodiment, as shown in FIG. 3 , the lifting shaft 1 is a split structure, that is, it includes a lifting shaft A and a lifting shaft B, and the lifting shaft A and the lifting shaft B are connected by a lifting shaft connector 12, and the lifting shaft connector 12 connects the lifting shaft A and the lifting shaft B into a whole shaft, and the axes of the lifting shaft A and the lifting shaft B coincide. Of course, the lifting shaft 1 can also adopt an integral structure, directly using a whole shaft.

Referring to Figures 1 to 3, the lifting shaft 1 is also sleeved with a synchronous pulley 11 that rotates synchronously with it. The synchronous pulley 11 is key-connected to the lifting shaft 1. The lifting drive member is connected by The synchronous belt transmits power to the synchronous pulley 11, thereby driving the lifting shaft 1 to rotate.

As shown in Figures 1 and 2, the lifting mechanism further includes a base plate 7, and the lifting shaft 1 is rotatably connected to the base plate 7. A bearing seat 71 is fixed to the base plate 7, and the lifting shaft 1 is inserted into the bearing seat 71 and rotatably connected to the bearing seat 71. In this embodiment, two bearing seats 71 are provided to improve the stability of the rotation of the lifting shaft 1.

The lifting drive member is a motor, which is fixed on the base plate 7. The stator end of the conductive slip ring 4 is fixed on the base plate 7 through a mounting bracket 72, and the stator end of the conductive slip ring 4 remains stationary.

As shown in Figure 3, when the lifting mechanism is working, the base plate 7 is placed horizontally, and the lifting shaft 1 is parallel to the base plate 7 and also placed horizontally. The conductive belt 3 needs to be extended to different vertical planes to form a triangular structure, and then connected to different positions of the grabbing mechanism. The triangular structure has high stability and can improve the stability of the lifting of the grabbing mechanism. However, the three winding wheels 2 are sleeved on a lifting shaft, so they are located on the same vertical plane. It is necessary to extend part of the conductive belt 3 horizontally for a distance and then turn vertically to turn the horizontal direction into the vertical direction to lift the grabbing mechanism. Therefore, a steering wheel 8 corresponding to the conductive belt 3 is provided on the base plate 7, and the steering wheel 8 is rotatably connected to the base plate 7. The steering wheel 8 can rotate along its own axis when the conductive belt 3 is lifted and lowered. The conductive belt 3 extending horizontally on the winding wheel 2 is turned to the vertical direction after passing through the steering wheel 8.

Both ends of the steering wheel 8 are provided with flanges along the circumference, and the conductive belt 3 is limited between the two flanges. Therefore, the structure of the steering wheel 8 can also limit the axial position of the conductive belt 3.

In one embodiment, as shown in FIG3 , a pair of follower wheels 9 are provided under each steering wheel 8, and the pair of follower wheels 9 are respectively located on both sides of the conductive belt 3. The conductive belt 3 will move along the axial direction of the lifting shaft 1 during the lifting movement. 5 and the flange of the guide wheel are axially limited, the side of the conductive belt 3 will generate sliding friction with the baffle 5 or the flange, affecting the belt life and the cleanliness of the purification room. Each conductive belt 3 corresponds to a pair of follower wheels 9 located below the steering wheel 8. When the conductive belt 3 is running, the follower wheels 9 rotate with the rise and fall of the conductive belt 3, which not only constrains the axial position of the conductive belt 3, but also converts the sliding friction between the conductive belt 3 and the baffle 5 or the flange into rolling friction between the conductive belt 3 and the follower wheels 9, greatly reducing the wear of the conductive belt 3.

As shown in FIG. 13 , the follower wheel 9 is provided with a guide ring groove 91 along the circumferential direction for the side edge of the conductive belt 3 to be embedded, and the side edge of the conductive belt 3 is always located in the guide ring groove 91. The guide ring groove 91 is an arc-shaped structure.

In one embodiment, the spacing between a pair of follower wheels 9 is adjustable for ease of adjustment. The central axis of each follower wheel 9 is fixed on a fixed block, and the two fixed blocks are jointly arranged on a fixed plate, and the fixed plate is fixed to the base plate 7. The positions of the two fixed blocks on the fixed plate are adjustable to adjust the spacing between the two follower wheels 9. The fixed block is fixed to the fixed plate by bolts, and a waist-shaped hole for the bolt to pass through is provided on the fixed block. The bolt can slide in the waist-shaped hole, and the position adjustment and fixation of the fixed block are achieved through the cooperation of the waist-shaped hole and the bolt. The conductive belt 3 passes between the pair of follower wheels 9. At this time, the bolt is loosened to adjust the position of the fixed block. When the fixed block is moved to the optimal position, the bolt is locked in the waist-shaped hole to fix the position of the follower wheel 9.

For the conductive belt 3 extending a long distance in the horizontal direction, a transition wheel 10 is rotatably connected to the base plate 7 , and the transition wheel 10 is arranged close to the winding wheel 2 .

In this embodiment, as shown in FIG. 3 , the conductive belts 3 on the winding wheels 2 on the left and right sides extend too long in the horizontal direction. A transition wheel 10 is provided at each of the winding wheels 2, and the conductive belt on the winding wheel 2 passes through the transition wheel 10, the steering wheel 8 and a pair of follower wheels 9 in sequence. The conductive belt 3 on the winding wheel 2 in the middle has a very short horizontal extension distance, so a steering wheel 8 can be directly provided near the winding wheel 2 in the middle, and the conductive belt 3 on the winding wheel 2 in the middle directly passes through the steering wheel 8 and turns to enter the pair of follower wheels 9. The structure of the transition wheel 10 is the same as that of the steering wheel 8.

The lifting shaft 1 , the winding wheel 2 , the transition wheel 10 , the steering wheel 8 and the follower wheel 9 are all located above the base plate 7 .

When installing the conductive belt 3 of this embodiment, first insert one end of the conductive belt 3 from the entrance of channel 1 25, close to the inclined surface 252 or the curved surface into the guide channel 24, and pass through the guide channel 24. At this time, there are still cables extending out of the conductive belt 3 (the belt body of the conductive belt 3 is stripped in advance). The cable continues to enter the channel 2 26 along the guide channel 24. The channel 2 26 corresponds to the position of the wiring groove 1a. The cable passes through the wiring groove 1a on the lifting shaft 1 and is connected to the conductive slip ring 4. After the cable is connected, the pressing sheet is inserted from the notch 224 to fix the conductive belt 3 in the guide channel 24. At this time, the conductive belt 3 has been fixed to the winding wheel 2. The other end of the conductive belt 3 is fixed to the gripping mechanism through the transition wheel 10, the steering wheel 8 and a pair of follower wheels 9 in sequence. When the lifting shaft 1 rotates, since one end of the conductive belt 3 has been fixed to the winding wheel 2, the conductive belt 3 is wound or unwound on the winding wheel 2 to lift the gripping mechanism. In this process, on the one hand, since a guide channel 24 is machined on the winding wheel 2 between its outer ring surface 211 and the shaft hole 23, the end of the conductive belt 3 is fixed in the guide channel 24, so that the conductive belt 3 can be tightly attached to the outer ring surface 211 of the winding wheel 2, ensuring the positioning of the lifting movement of the conductive belt 3. On the other hand, the guide channel 24, the second channel 26 and the wiring trough 1a cooperate to facilitate the wiring of the cables and effectively protect the cables.

The above implementation modes are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the content of the present invention and implement it, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims (13)

A lifting mechanism, characterized in that: A lifting shaft, wherein the lifting shaft can rotate along its own axis; A winding wheel, at least one of which is sleeved on the lifting shaft and rotates synchronously with the lifting shaft, each of which comprises an outer ring surface, an axial hole, a channel 1, a channel 2 and a guide channel, the axial hole is for the lifting shaft to pass through, the guide channel is located between the axial hole and the outer ring surface and is arranged around the axial hole, the guide channel is connected to the channel 1 that passes through the outer ring surface, and the channel 2 is arranged between the guide channel and the axial hole and connects the two; The winding wheel comprises two end faces located on both sides of the outer ring face, each end face is provided with a groove along the axial direction, the grooves are arranged at intervals along the circumferential direction on the corresponding end face, the grooves on the two end faces are arranged alternately, and the groove on one end face can conduct the two adjacent grooves on the other end face; A conductive slip ring is arranged at the end of the lifting shaft, and a rotor end of the conductive slip ring is fixed to the lifting shaft and rotates synchronously. The lifting mechanism according to claim 1 is characterized in that it also includes a lifting belt, the lifting belt is wound on the outer annular surface, and the lifting belt is passed through the inner end of the guide channel and fixed in the guide channel. The lifting mechanism according to claim 2 is characterized in that: the channel 1 is arranged along the radial direction of the winding wheel, the side of the channel 1 close to the outer annular surface is the entrance of the lifting belt, and an arc-shaped chamfer is formed between the side wall of the channel 1 at the entrance and the outer annular surface. The lifting mechanism according to claim 3 is characterized in that: the channel 1 has at least one inclined surface or curved surface, the lifting belt fits on the inclined surface or curved surface to enter the guide channel, and the cross-sectional area of the channel 1 gradually increases from close to the outer annular surface to far away from the outer annular surface. The lifting mechanism according to claim 1 is characterized in that: the guide channel surrounds the entire shaft hole; or the guide channel surrounds a portion of the shaft hole. The lifting mechanism according to claim 1 is characterized in that: the winding wheel includes a winding portion and fixed portions located on both sides of the winding portion along the axial direction, the winding portion and the fixed portion are coaxial cylindrical structures, and the diameter of the winding portion is greater than the diameter of the fixed portion, the side surface of the winding portion is an outer annular surface, and the surfaces of the two fixed portions away from the winding portion are end surfaces with grooves, and the grooves extend to the winding portion. The lifting mechanism according to claim 6 is characterized in that: the end of the lifting belt is fixed in the guide channel by a pressing plate, a notch connected to the guide channel is radially opened on the side wall of the fixing part, a bolt hole corresponding to the notch is opened on the fixing part, and the pressing plate is fixed to the fixing part by a bolt threadedly connected to the bolt hole. The lifting mechanism according to any one of claims 2 to 4 is characterized in that: each of the winding wheels is fixed with baffles located on both sides of the outer annular surface, the baffles are annular structures and are coaxially arranged with the winding wheel, the baffles extend out of the winding wheel, and a cavity for winding the lifting belt is defined between the two baffles and the outer annular surface; The baffle is provided with an inclined wedge-shaped surface on one side facing the outer annular surface. The wedge-shaped surface is provided at the portion of the baffle extending out of the winding wheel. Each of the wedge-shaped surfaces expands outwards from the side close to the outer annular surface to the side away from the outer annular surface. The lifting mechanism according to claim 8 is characterized in that the baffle is a split structure, including at least two split parts, each of the split parts is detachably connected to the winding wheel, and the split parts can be spliced to form a baffle with an annular structure. The lifting mechanism according to claim 2 is characterized in that: the lifting belt is a conductive belt, the cable in the conductive belt enters the shaft hole from channel two, and passes through the winding wheel and the lifting shaft to be connected to the rotor end; the side wall of the lifting shaft is provided with a wiring groove along the axis, and when the lifting shaft is keyed to the winding wheel, the position of the wiring groove corresponds to channel two, and the cable passing through channel two is connected to the rotor end of the conductive slip ring along the wiring groove. The lifting mechanism according to claim 1 is characterized in that: the rotor end is connected to the lifting shaft through a connecting assembly, the connecting assembly includes a connecting piece and a fixing piece, the connecting piece is fixed to the end of the lifting shaft, and the fixing piece is used to connect the rotor end to the connecting piece to achieve synchronous rotation of the rotor end and the connecting piece. The lifting mechanism according to claim 11 is characterized in that: the connecting member comprises a circular connecting plate and an annular vertical wall extending along the side of the connecting plate, the connecting plate is fixed to the end of the lifting shaft, and a plug-in cavity for inserting the rotor end is defined between the connecting plate and the annular vertical wall, and the rotor end is suspended and plugged into the plug-in cavity; the part of the fixing member located in the plug-in cavity is tensioned into a limiting plane that fits the plane of the rotor end, the rotor end is located in the limiting cavity defined by the limiting plane and rotates synchronously with the limiting plane under the push of the limiting plane, and the end of the fixing member is fixed to the outer wall of the annular vertical wall through the limiting groove; The fixing piece is a belt body made of metal or plastic material, and a clearance groove for the end of the belt body to pass through is provided on the annular vertical wall. The lifting mechanism according to claim 2 is characterized in that: each of the lifting belts corresponds to a steering wheel, and the lifting belt extending horizontally from the winding wheel is turned to a vertical direction after passing through the steering wheel; A pair of follower wheels with adjustable spacing are also arranged below each of the steering wheels. The pair of follower wheels are respectively located on both sides of the lifting belt and abut against the side edges of the lifting belt.