CN202743929U

CN202743929U - Silicon slice automatic blanking device

Info

Publication number: CN202743929U
Application number: CN201220415728.7U
Authority: CN
Inventors: 戴秋喜; 查俊
Original assignee: KUTTLER AUTOMATION SYSTEMS (SUZHOU) CO Ltd
Current assignee: KUTTLER AUTOMATION SYSTEMS (SUZHOU) CO Ltd
Priority date: 2012-08-21
Filing date: 2012-08-21
Publication date: 2013-02-20
Anticipated expiration: 2022-08-21

Abstract

The utility model discloses a silicon slice automatic blanking device which comprises a first conveying organization which is used for conveying a silicon slice which is from a wet processing equipment, a first conveyor belt arranged in the first conveying organization, a second conveyor belt and a third conveyor belt which are identical to the first conveying organization in the conveying direction and are respectively connected with the first conveyor belt in butted mode, a second conveying organization which is connected with the third conveyor belt in butted mode, is identical to the third conveyor belt in the conveying direction, and is used for conveying the silicon slice to a blanking area, a first sensor which is used for inducting when the silicon slice arrives at the second conveyor belt and the third conveyor belt, a second sensor which is used for inducting when the silicon slice arrives at a corner conveying device, a third sensor which is used for inducting when the silicon slice arrives at the second conveying organization. The silicon slice automatic blanking device has the advantages of improving greatly productivity, reducing the labor intensity, also reducing the cost, and being easy to manufacture and install at the same time.

Description

Silicon chip automatic blanking equipment

Technical field

The utility model relates to the blanking equipment on the silicon chip manufacturing line, relates in particular to a kind of silicon chip automatic blanking equipment of realizing multiple tracks.

Background technology

The most silicon slice charging all is artificial blanking, and not only efficient is low, lavish labor on, and fragile silicon chip and affect the silicon chip battery conversion ratio, a lot of silicon slice charging machine production capacities is low besides.Blanking machine of the prior art as shown in Figure 1, when 5 road silicon chips are sent to tail end from the starting end of conveyer A along arrow a, at this time silicon chip divides both direction (arrow b direction), collect Carrier box by transferring machine B to the both sides transmission, then Carrier box passes to the upper strata (lower floor of C is empty Carrier box rest area) of blanking machine C, waits for manually and taking out.When 5 silicon chips were received the Carrier box the inside, 5 silicon chips next time also began transmission from A, have so just formed an endlessly process.Whole process time is very long, and production capacity is very low, can not satisfy the need of production of extensive silicon chip, and easily produces fragment.

The utility model content

Technical problem to be solved in the utility model provides a kind of silicon chip automatic blanking equipment, can greatly improve production capacity, and efficient is high, has reduced labour intensity, has also reduced cost, and this equipment is easy to make and install simultaneously.

In order to solve the problems of the technologies described above, the utility model provides a kind of silicon chip automatic blanking equipment, comprising:

The first connecting gear, described the first connecting gear comprise at least two groups the first belt conveyor that all is on the same level face, and every group of described first belt conveyor is for dock to transmit the silicon chip that comes from wet process equipment with wet process equipment;

The second belt conveyor and the 3rd belt conveyor that direction of transfer is identical with described the first connecting gear, described the second belt conveyor and the 3rd belt conveyor dock with two groups of described first belt conveyor respectively, described the second belt conveyor and the 3rd belt conveyor below are provided with the corner conveyer, described corner conveyer comprises lifting mechanism, three driving faces that the section gap that is connected with lifting mechanism arranges, three described driving faces are on the same level face and with described the second belt conveyor be used for vertical with the transmission direction of the 3rd belt conveyor the silicon chip on described the second belt conveyor are transferred to described the 3rd belt conveyor, and the gap that described the second belt conveyor of confession or the 3rd belt conveyor wear after being formed on described lifting mechanism between adjacent two described driving faces and promoting;

Second connecting gear identical with described the 3rd belt conveyor docking and direction of transfer is used for silicon chip is delivered to discharging area;

First sensor, described first sensor are arranged on described the second belt conveyor and the 3rd belt conveyor and the position that described the first belt conveyor docks and are used for sending the primary importance signal when silicon chip arrive described the second belt conveyor and the 3rd belt conveyor;

The second sensor, described the second sensor setting is in be used for sending second place signal on the position of described corner conveyer when silicon chip arrives described corner conveyer;

The 3rd sensor, described the 3rd sensor setting is used for sending three position singal when silicon chip arrives described the second connecting gear on described the 3rd belt conveyor and position that described the second connecting gear docks.

As preferably, described discharging area comprises outside gear mechanism, unloader structure and four-sensor, wherein:

Described outside gear mechanism comprises transfer station and lower transfer station, described upper transfer station is provided with for the 4th belt conveyor that transmits fully loaded silicon wafer bearing box, be on the same level face with described the second connecting gear and direction of transfer identical, described lower transfer station is provided be used to the 5th belt conveyor that transmits unloaded silicon wafer bearing box and its direction of transfer opposite with described the 4th belt conveyor;

Described unloader structure is arranged at described the second connecting gear along the end of direction of transfer, comprise the first bay-lift, be provided with on described the first bay-lift can dock with described the 4th belt conveyor respectively at different lifting position places with the fully loaded silicon wafer bearing box of the described transmission of support or with described the 5th belt conveyor and dock the 6th belt conveyor that transmits described unloaded silicon wafer bearing box with support;

Described four-sensor is arranged on the position of described unloader structure, and the zero load/full signal of induction silicon wafer bearing box is used for controlling the action of described the first bay-lift and described the 6th belt conveyor.

As preferably, be provided with buffer memory mechanism between described unloader structure and the second connecting gear, described buffer memory mechanism comprises the silicon chip Cache Framework that the second bay-lift and two sides connect, described the second connecting gear vertically runs through described silicon chip Cache Framework, and described the second bay-lift is connected with described silicon chip Cache Framework and is used for the described silicon chip Cache Framework of lifting on perpendicular to the direction of transfer of described the second connecting gear.

As preferably, described the second connecting gear comprises support, support platform, be located at a plurality of rollers of support platform both sides, be divided on the roller of described support platform both sides and be used for the 7th belt conveyor of transmission silicon chip, and is used for driving the motor that described roller rotates,

Described support platform is comprised of fixed part and pars contractilis, and described fixed part is captiveed joint with support, is connected by cylinder between described fixed part and the pars contractilis, and the flexible direction of described cylinder is consistent with the direction of transfer of described the 7th belt conveyor;

Described roller arranges in pairs, and two rollers that consist of every pair roller are divided into support platform both sides accordingly, and described roller comprises a pair of live roller, a pair of the first return idler, a pair of the second return idler and a pair of the 3rd return idler at least; A pair of described live roller is individually fixed in the two ends of a transmission shaft, and described transmission shaft is located at the end of fixed part one side of support platform, and described transmission shaft is connected with motor;

A pair of described the first return idler is located at the two ends of the first wheel shaft, the first round is located in the end of pars contractilis one side of support platform, a pair of described the second return idler is located at the two ends of the second wheel shaft, described second takes turns an end that is located in the close described fixed part of described pars contractilis, a pair of described the 3rd return idler is located at the two ends of third round axle, described third round is located on the support of described pars contractilis below, described third round axle is lower than described the second wheel shaft, described the second wheel shaft is lower than described the first wheel shaft, and described the second wheel shaft is compared to described the first wheel shaft and the most close described fixed part of third round axle;

Described the 7th belt conveyor is walked around respectively live roller, the first return idler, the second return idler and the 3rd return idler of described support platform both sides successively, makes described the 7th belt conveyor respectively through circuitous formation multistage folded section after being positioned at described second return idler of the same side and the 3rd return idler.

Compared with prior art, the beneficial effect of silicon chip automatic blanking equipment of the present utility model is:

1, by between the second belt conveyor and the 3rd belt conveyor, the corner conveyer being set, so that silicon chip is transformed into one output by the twice input in transport process, improve production capacity, and be applied to the device that can save mouth repetition in the prior art in the channel blanking equipment;

2, outside gear mechanism is realized automatically turnover Carrier box operation, manually unloaded silicon wafer bearing box is placed in lower floor's transmission of outside gear mechanism, takes fully loaded silicon wafer bearing box above the transmission of upper strata away, has reduced artificial labour intensity, has further increased production capacity simultaneously.

Description of drawings

Fig. 1 is the structural representation of blanking machine in the prior art;

Fig. 2 is the planar structure scheme drawing of the silicon chip automatic blanking equipment of embodiment of the present utility model;

Fig. 3 is the structural representation of corner conveyer of the silicon chip automatic blanking equipment of embodiment of the present utility model;

Fig. 4 is the structural representation of unloader structure of the silicon chip automatic blanking equipment of embodiment of the present utility model;

Fig. 5 is the unloader structure of silicon chip automatic blanking equipment of embodiment of the present utility model and the scheme drawing one of outside gear mechanism cooperating;

Fig. 6 is the unloader structure of silicon chip automatic blanking equipment of embodiment of the present utility model and the scheme drawing two of outside gear mechanism cooperating;

Fig. 7 is the structural representation of buffer memory mechanism of the silicon chip automatic blanking equipment of embodiment of the present utility model;

Fig. 8 is the structural representation of the second connecting gear of the silicon chip automatic blanking equipment of embodiment of the present utility model;

Fig. 9 is the inner structure scheme drawing of the second connecting gear of the silicon chip automatic blanking equipment of embodiment of the present utility model.

Main description of reference numerals

The fully loaded silicon wafer bearing box of the unloaded silicon wafer bearing box 200-of 100-

1-the first belt conveyor 2-the second belt conveyor

3-the 3rd belt conveyor 4-the 4th belt conveyor

5-the 5th belt conveyor 6-unloader structure

61-the 6th belt conveyor 62-the first bay-lift

7-the second connecting gear 71-support

72-the 7th belt conveyor 73-drive wheel

74-cylinder 75-live roller

76-the first return idler 77-the second return idler

78-the 3rd return idler 701-pars contractilis

The cover plate 702-fixed part of 7011-pars contractilis

The cover plate 703-folded section of 7021-fixed part

8-

corner conveyer

81,82,83-driving face

801,802-gap 9-buffer memory mechanism

91-silicon chip Cache Framework 92-the second bay-lift

10-first sensor 20-the second sensor

30-the 3rd sensor 40-four-sensor

11-outside gear mechanism 751-transmission shaft

761-the first wheel shaft 771-the second wheel shaft

781-third round axle

The specific embodiment

Below in conjunction with the drawings and specific embodiments silicon chip automatic blanking equipment of the present utility model is described in further detail, but not as to restriction of the present utility model.

Fig. 1 is the structural representation of blanking machine in the prior art; Fig. 2 is the planar structure scheme drawing of the silicon chip automatic blanking equipment of embodiment of the present utility model; Fig. 3 is the structural representation of corner conveyer of the silicon chip automatic blanking equipment of embodiment of the present utility model; Fig. 4 is the structural representation of unloader structure of the silicon chip automatic blanking equipment of embodiment of the present utility model; Fig. 5 is the unloader structure of silicon chip automatic blanking equipment of embodiment of the present utility model and the scheme drawing one of outside gear mechanism cooperating; Fig. 6 is the unloader structure of silicon chip automatic blanking equipment of embodiment of the present utility model and the scheme drawing two of outside gear mechanism cooperating; Fig. 7 is the structural representation of buffer memory mechanism of the silicon chip automatic blanking equipment of embodiment of the present utility model; Fig. 8 is the structural representation of the second connecting gear of the silicon chip automatic blanking equipment of embodiment of the present utility model; Fig. 9 is the inner structure scheme drawing of the second connecting gear of the silicon chip automatic blanking equipment of embodiment of the present utility model.To shown in Figure 9, the blanking machine that becomes 3 road silicon chip outputs take 5 road silicon chip inputs is the example explanation such as Fig. 2, and the silicon chip automatic blanking equipment of embodiment of the present utility model comprises:

The first connecting gear, described the first connecting gear comprises at least two groups the first belt conveyor 1 that all is on the same level face, 5 road silicon chip input structures have been provided in the present embodiment, namely, the first connecting gear comprises 5 group of first belt conveyor 1, and every group of first belt conveyor 1 docks with wet process equipment and be used for transmitting the silicon chip that comes from wet process equipment;

The second belt conveyor 2 that direction of transfer is identical with the first connecting gear and the 3rd belt conveyor 3, the second belt conveyor 2 and the 3rd belt conveyor 3 dock with two group of first belt conveyor 1 respectively, the second belt conveyor 2 and the 3rd belt conveyor 3 belows are provided with corner conveyer 8, corner conveyer 8 comprises that lifting mechanism is (not shown, all can realize the equipment of elevating function can to adopt lift cylinder etc.), three driving faces 81 that the section gap that is connected with lifting mechanism arranges, 82,83, three driving faces 81,82,83 are on the same level face and with the second belt conveyor 2 be used for vertical with the transmission direction of the 3rd belt conveyor 3 silicon chip on the second belt conveyor 2 are transferred to the 3rd belt conveyor 3, and adjacent two driving faces, it is driving face 81, between 82 and driving face 82, between 83, the gap 801 of formation, 802 wear for the second belt conveyor 2 and the 3rd belt conveyor 3 respectively;

Second connecting gear 7 identical with 3 docking of the 3rd belt conveyor and direction of transfer is used for silicon chip is delivered to discharging area;

First sensor 10, primary importance signal when first sensor 10 is arranged at and is used for the induction silicon chip on the second belt conveyor 2 and the 3rd belt conveyor 3 and the position that the first belt conveyor 1 docks and arrives the 3rd belt conveyor 3, according to this primary importance signal, the second belt conveyor 2 and the 3rd belt conveyor 3 become at a high speed to pull open the spacing of the 5 silicon chip groups in front and back, with the whole transfer rate of further raising;

Second place signal when the second sensor 20, the second sensors 20 are arranged at and are used for the induction silicon chip on the position of corner conveyer 8 and arrive corner conveyer 8; The 3rd sensor 30, the three sensors 30 are arranged on the 3rd belt conveyor 3 and the position that the second connecting gear 7 docks and are used for the three position singal that the induction silicon chip arrives the second connecting gear 7.According to this second place signal and three position singal, control the running state of the second belt conveyor 2, the 3rd belt conveyor 3 and corner conveyer 8.Wherein, silicon chip on the 3rd belt conveyor 3 will directly be sent on the second connecting gear 7, when the silicon chip on the second belt conveyor 2 arrives corner conveyer 8 position, the lifting mechanism of corner conveyer 8 promotes, the second belt conveyor 2 and the 3rd belt conveyor 3 gap 801 of submerging, in 802, driving face 81,82,83 are promoted to and exceed the second belt conveyor 2 and the 3rd belt conveyor 3, after holding up silicon chip it is transferred on the 3rd belt conveyor 3, then 8 declines of corner conveyer reset, silicon chip namely is placed on the 3rd belt conveyor 3, finish turning to of silicon chip, next silicon chip is transmitted by the 3rd belt conveyor 3.Corner conveyer 8 waits for that lower a slice silicon chip arrives.After the second belt conveyor 2, the 3rd belt conveyor 3 are finished the transmission of front a collection of silicon chip, reset to the state that receives the next group silicon chip.

As improvement, the discharging area of the silicon chip automatic blanking equipment of embodiment of the present utility model comprises outside gear mechanism, unloader structure and four-sensor, wherein:

Outside gear mechanism 11 comprises transfer station and lower transfer station, upper transfer station is provided with for the 4th belt conveyor 4 that transmits fully loaded silicon wafer bearing box, be on the same level face with the second connecting gear 7 and direction of transfer identical, lower transfer station is provided be used to the 5th belt conveyor 5 that transmits unloaded silicon wafer bearing box and its direction of transfer opposite with the 4th belt conveyor 4;

Unloader structure 6 is arranged at the second connecting gear 7 along the end of direction of transfer, comprise the first bay-lift 62, be provided with on the first bay-lift at different lifting position places and can butt up against respectively the 4th belt conveyor 4 transmits unloaded silicon wafer bearing box 100 with support with the fully loaded silicon wafer bearing box 200 of support transmission and the 5th belt conveyor 5 the 6th belt conveyor 61, the unloaded silicon wafer bearing box that the 6th belt conveyor 6 supports the 5th belt conveyor 5 is sent here, fully loaded silicon wafer bearing box is by in the process of the continuous jacking of the first bay-lift 62, collect successively the silicon chip that the second conveyer 7 structures are sent here, after silicon wafer bearing box is fully loaded, delivered to the 4th belt conveyor 4 by the 6th belt conveyor 6;

Such as Fig. 2, Fig. 5 and shown in Figure 6, four-sensor 40 is arranged on the position of unloader structure 6, and the zero load/full signal of induction silicon wafer bearing box is used for the action of control the first bay-lift 62 and the 6th belt conveyor 61.The first bay-lift 62 drops to as shown in Figure 5 position, under the signal control that four-sensor 40 is sensed, the 6th belt conveyor 61 direction of transfers are identical with the direction of transfer of the 5th belt conveyor 5, receive unloaded silicon wafer bearing box 100, then the first bay-lift 62 rises, the unloaded silicon wafer bearing box 100 of the 6th belt conveyor 61 support under four-sensor 40 actuated signal controls is taken in the silicon chip that the second connecting gear 7 is sent here, then adjust to as shown in Figure 6 position, the 6th belt conveyor 61 direction of transfers are identical with the direction of transfer of the 4th belt conveyor 4, will be fully loaded with silicon wafer bearing box 200 and deliver to the final blanking of the 4th belt conveyor 4 realization silicon chips.

As further improvement, be provided with buffer memory mechanism 9 between unloader structure 6 and the second connecting gear 7, buffer memory mechanism 9 comprises the silicon chip Cache Framework 91 that the second bay-lift 92 and two sides connect, the second connecting gear 7 vertically runs through silicon chip Cache Framework 91, the second bay-lift 92 is connected with silicon chip Cache Framework 91, be used for lifting silicon chip Cache Framework 91 on perpendicular to the direction of transfer of the second connecting gear 7, cooperate one by one with the second connecting gear 7 silicon chip Cache Framework 91 is carried out inserted sheet, this structure belongs to prior art, repeats no more.

As further improving, the second connecting gear 7 comprises support 71, support platform, be located at a plurality of rollers of support platform both sides, be divided on the roller of support platform both sides and be used for the 7th belt conveyor 72 of transmission silicon chip, and is used for driving the motor (not shown) that roller rotates;

The support platform is comprised of fixed part 702 and pars contractilis 701, and fixed part 702 is captiveed joint with support 71, is connected by cylinder 74 between fixed part 702 and the pars contractilis 701, and the flexible direction of cylinder is consistent with the direction of transfer of the 7th belt conveyor 72; Roller arranges in pairs, and two rollers that consist of every pair roller are divided into support platform both sides accordingly, and roller comprises a pair of live roller 75, a pair of the first return idler 76, a pair of the second return idler 77 and a pair of the 3rd return idler 78 at least; A pair of live roller 75 is individually fixed in the two ends of a transmission shaft 751, and transmission shaft 751 is located at the end of fixed part 702 1 sides of support platform, and transmission shaft 751 is connected with motor; A pair of the first return idler 76 is located at the two ends of the first wheel shaft 761, the first wheel shaft 761 is located at the end of pars contractilis 701 1 sides of support platform, a pair of the second return idler 77 is located at the two ends of the second wheel shaft 771, the second wheel shaft 771 is located at pars contractilis 701 near an end of fixed part 702, a pair of the 3rd return idler 78 is located at the two ends of third round axle 781, third round axle 781 is located on the support of pars contractilis 701 belows, third round axle 781 is lower than the second wheel shaft 771, the second wheel shaft 771 is lower than the first wheel shaft 761, and the second wheel shaft 771 is compared to the first wheel shaft 761 and third round axle 781 the most close fixed parts 702; The 7th belt conveyor 72 is walked around respectively live roller 75, the first return idler 76, the second return idler 77 and the 3rd return idler 78 of support platform both sides successively, makes the 7th belt conveyor 72 respectively through circuitous formation multistage folded section 703 after being positioned at second return idler 77 of the same side and the 3rd return idler 78.

Above embodiment is exemplary embodiment of the present utility model only, is not used in restriction the utility model, and protection domain of the present utility model is defined by the claims.Those skilled in the art can make various modifications or be equal to replacement the utility model in essence of the present utility model and protection domain, this modification or be equal to replacement and also should be considered as dropping in the protection domain of the present utility model.

Claims

1. A silicon wafer automatic unloading equipment, is characterized in that, comprises:

A first conveying mechanism, the first conveying mechanism includes at least two groups of first conveying belts all on the same level, and each group of the first conveying belts is used to interface with the wet process equipment to transport silicon wafers from the wet process equipment;

The second conveyor belt and the third conveyor belt with the same conveying direction as the first conveyor mechanism, the second conveyor belt and the third conveyor belt are respectively docked with two groups of the first conveyor belts, and the second conveyor belt and the third conveyor belt are arranged below There is a corner transmission device, the corner transmission device includes a lifting mechanism, three transmission surfaces connected with the lifting mechanism and arranged at intervals, the three transmission surfaces are on the same horizontal plane and are connected to the second conveyor belt and the third conveyor belt The transmission direction is vertical to transfer the silicon wafers on the second conveyor belt to the third conveyor belt, and the two adjacent transmission surfaces are formed between the second conveyor belt or the second conveyor belt after the lifting mechanism is lifted. the gap through which the third conveyor belt passes;

A second conveying mechanism docked with the third conveying belt and having the same conveying direction, used to convey silicon wafers to the unloading area;

A first sensor, the first sensor is arranged on the position where the second conveyor belt and the third conveyor belt are docked with the first conveyor belt, and is used to send out the first position when the silicon wafer arrives at the second conveyor belt and the third conveyor belt Signal;

a second sensor, the second sensor is arranged at the position of the corner transfer device for sending a second position signal when the silicon wafer arrives at the corner transfer device;

A third sensor, where the third sensor is arranged at a position where the third conveying belt is docked with the second conveying mechanism, is used for sending a third position signal when the silicon wafer arrives at the second conveying mechanism.

2. The silicon wafer automatic unloading equipment according to claim 1, characterized in that, the unloading area includes an outer transmission mechanism, a plate receiving mechanism and a fourth sensor, wherein:

The outer transmission mechanism includes an upper transmission platform and a lower transmission platform. The upper transmission platform is provided with a fourth conveyor belt for transmitting a full load of silicon wafer carrier boxes, which is on the same level as the second transmission mechanism and in the same transmission direction. The following conveying station is provided with a fifth conveying belt for conveying empty silicon wafer carrier boxes and its conveying direction is opposite to that of the fourth conveying belt;

The plate receiving mechanism is arranged at the end of the second conveying mechanism along the conveying direction, and includes a first lifting platform, and the first lifting platform is provided with different lifting positions that can respectively dock with the fourth conveying belt to a sixth conveyor belt for supporting the full-loaded silicon wafer carrier box or docking with the fifth conveyor belt to support the empty silicon wafer carrier box;

The fourth sensor is arranged at the position of the receiving mechanism to sense the empty/full load signal of the silicon wafer carrier box for controlling the movement of the first lifting platform and the sixth conveyor belt.

3. The automatic unloading equipment for silicon wafers according to claim 2, characterized in that, a buffer mechanism is arranged between the plate receiving mechanism and the second conveying mechanism, and the buffer mechanism includes a second lifting platform and a double-sided penetrating A silicon wafer cache frame, the second transmission mechanism vertically penetrates the silicon wafer cache frame, and the second lifting platform is connected to the silicon wafer cache frame for lifting in a transmission direction perpendicular to the second transmission mechanism The silicon cache framework.

4. The silicon wafer automatic unloading equipment according to claim 1, characterized in that, the second transmission mechanism includes a bracket, a supporting platform, a plurality of rollers arranged on both sides of the supporting platform, and separately arranged on the supporting platform. The seventh conveyor belt used to transport silicon wafers on the rollers on both sides of the supporting platform, and the motor used to drive the rollers to rotate,

The supporting platform is composed of a fixed part and a telescopic part, the fixed part is fixedly connected with the bracket, and the fixed part and the telescopic part are connected by a cylinder, and the telescopic direction of the cylinder is in line with the conveying direction of the seventh conveyor belt. consistent;

The rollers are arranged in pairs, and the two rollers constituting each pair of rollers are correspondingly arranged on both sides of the supporting platform, and the rollers at least include a pair of driving rollers, a pair of first driven rollers, and a pair of second driven rollers and a pair of third driven rollers; a pair of said transmission rollers are respectively fixed on the two ends of a transmission shaft, said transmission shaft is arranged at the end of one side of the fixed part of the supporting platform, and said transmission shaft is connected with the motor ;

A pair of the first driven rollers are arranged at both ends of the first axle, the first axle is arranged at the end of one side of the telescopic part of the support platform, and a pair of the second driven rollers are arranged at the end of the second axle. two ends, the second wheel shaft is set at one end of the telescopic part close to the fixed part, a pair of the third driven rollers are set at both ends of the third wheel shaft, and the third wheel shaft is set at the end of the telescopic part On the bracket under the upper part, the third axle is lower than the second axle, the second axle is lower than the first axle, and the second axle is lower than the first axle and the third axle closest to the fixing portion;

The seventh conveyor belt respectively bypasses the driving rollers, the first driven roller, the second driven roller and the third driven roller on both sides of the supporting platform in turn, so that the seventh conveyor belt is respectively located on the same side The second driven roller and the third driven roller then detour to form a multi-section folding section.