CN108723342B

CN108723342B - A upset machine for foundry goods clearance, detection transfer chain

Info

Publication number: CN108723342B
Application number: CN201810674107.2A
Authority: CN
Inventors: 张志红; 谢金法; 解晓琳; 马浩霖; 岳菊梅
Original assignee: Henan University of Science and Technology
Current assignee: Henan University of Science and Technology
Priority date: 2018-06-27
Filing date: 2018-06-27
Publication date: 2020-11-10
Anticipated expiration: 2038-06-27
Also published as: CN108723342A

Abstract

The utility model provides a upset machine for foundry goods clearance, detect transfer chain, including frame and two rotating disc, two rotating disc support through a pair of supporting wheel respectively, make two rotating disc can wind self axis free rotation, install in the frame and be used for driving the drive chain motion with drive rotating disc pivoted driving motor, set up the rectangular hole that is used for supplying the foundry goods to pass through on two rotating disc, install rollgang and last roller way down between two rotating disc, one side that rollgang kept away from down was equipped with two at least hold-down mechanisms to last roller way, drive the space between two adjacent rollers in the rollgang down of casting piece and pass through last roller way through hold-down mechanism, make the casting piece compress tightly the foundry goods on the roller way down. The turnover machine provided by the invention can be used for safely, efficiently and mechanically and automatically turning castings in the conveying line, and the turned castings can be continuously conveyed in the conveying line through the roller conveying system, so that the requirements of the conveying line on cleaning and detecting the castings without falling down are met.

Description

A upset machine for foundry goods clearance, detection transfer chain

Technical Field

The invention relates to the field of mechanical equipment for casting production, in particular to a turnover machine for a casting cleaning and detecting conveying line.

Background

The modern industry has higher and higher requirements on the production efficiency of castings along with the improvement of the automatic production level, the cleaning and detection conveying lines of the castings are carried in due course, and the hoisting and the conveying of the castings are reduced and the cleaning and the detection of the castings are realized without falling down by connecting the shot blasting, cleaning, detection and other equipment of the castings with a roller conveying system; the production process of the casting can be subjected to important procedures such as shakeout, shot blasting and the like, so that residual sand, steel shots and flash burrs which are not fallen completely are arranged on the whole body and inside of the casting, the casting can enter the subsequent machining procedure after being cleaned up, and after the cleaning procedure is finished, the holes, grooves and the like on the outer surface and inside of the casting are strictly checked and detected; in order to satisfy the clearance and the detection requirement of foundry goods, make all inside and outside surfaces of foundry goods can both obtain clearance and detection, must overturn to the foundry goods, to large-scale foundry goods, the current wire rope that uses through the manual work, the cooperation overhead traveling crane lifts by crane not only inefficiency with the mode that overturns, the incident appears easily still, consequently in the foundry goods clearance, detect the transfer chain, need use the upset machine to carry out mechanized automatic upset to the foundry goods, and make the foundry goods accessible roller table conveying system after the upset continue to carry in the transfer chain, in order to satisfy the transfer chain and carry out the needs of not falling to the ground clearance and detection to the foundry goods, promote production efficiency.

Disclosure of Invention

The invention aims to provide a turnover machine for a casting cleaning and detecting conveyor line, which can safely, efficiently and mechanically and automatically turn castings in the conveyor line, and can continuously convey the turned castings in the conveyor line through a roller conveying system, so that the requirement of the conveyor line for cleaning and detecting the castings without falling to the ground is met, and the production efficiency is improved.

The technical scheme adopted by the invention for solving the technical problems is as follows: the utility model provides a upset machine for foundry goods clearance, detection transfer chain, includes frame and two rotating disc, install two pairs in the frame and be used for supporting respectively two rotating disc's supporting wheel, the supporting wheel homoenergetic is all parallel to each other around self axis free rotation and all supporting wheel's axis, all has seted up on the outer circumference of all supporting wheels with rotating disc assorted race, the race of two supporting wheels of the same pair sets up relatively, the outer circumference of two rotating disc is pressed respectively on the race groove bottom of a pair of supporting wheel, makes two rotating disc homoenergetic freely rotate and the axis coincidence of two rotating disc around self axis to block the both ends face of establishing rotating disc with the restriction along its axial degree of freedom through the lateral wall of supporting wheel race, still install a plurality of spacing wheels in the frame, the outer circumference of spacing wheel is pressed and is established on rotating disc's outer circumference, so as to limit the displacement of the rotating disk and prevent the rotating disk from separating from the wheel groove of the supporting wheel;

the chain mounting ring is mounted on the end face of one of the two rotating discs, the outer diameter of the chain mounting ring is smaller than that of the rotating discs, the central axis of the chain mounting ring coincides with the central axis of the rotating discs, two chain fixing blocks are mounted on the outer circumference of the chain mounting ring, a driving motor for driving the driving chain to move so as to drive the rotating discs to rotate is further mounted on the rack, a driving chain wheel is mounted at the output end of the driving motor, the driving chain is meshed with the driving chain wheel, two ends of the driving chain surround the outer circumference of the chain mounting ring and are respectively connected with one chain fixing block, nuts for adjusting the tightness degree of the driving chain are arranged on the two chain fixing blocks, and a change wheel for increasing the surrounding range of the driving chain on the outer circumference of the chain mounting ring is further mounted on the rack;

rectangular holes for allowing castings to pass through are formed in the two rotating discs, a lower roller way, an upper roller way, two first connecting beams and at least one second connecting beam are arranged between the two rotating discs, two ends of the lower roller way are respectively installed on the inner walls of the rectangular holes of the two rotating discs, two ends of the upper roller way are respectively installed on the inner walls, opposite to the inner walls where the lower roller way is installed, of the rectangular holes of the two rotating discs, the lower roller way and the upper roller way are parallel to each other and symmetrically arranged about the central axis of the rotating discs, the two first connecting beams are respectively located on two sides of the rectangular holes of the rotating discs, and two ends of the first connecting beams and two ends of the second connecting beams are respectively and fixedly connected with the two rotating discs;

one of the two first connecting beams is provided with a roller way motor and a tensioning chain wheel, the output end of the roller way motor is provided with a double-row chain wheel, the end surface of one of the two rotating disks is provided with a lower chain wheel set and an upper chain wheel set, the roller way motor drives the double-row chain wheel to rotate and drives the lower chain wheel set and the upper chain wheel set to rotate through chain transmission, the lower chain wheel set drives the lower roller way to rotate through the chain transmission, the upper chain wheel set drives the upper roller way to rotate through the chain transmission, and the chain transmission between the double-row chain wheel and the upper chain wheel set is tensioned through the tensioning;

at least two pressing mechanisms are arranged on one side of the upper roller way, which is far away from the lower roller way, a mounting seat is arranged on the second connecting beam, the pressing mechanisms are hinged with the mounting seat, pressing pieces are arranged on all the pressing mechanisms, and the pressing pieces are driven by the pressing mechanisms to move towards the lower roller way and penetrate through a gap between two adjacent rollers in the upper roller way, so that castings are pressed on the lower roller way by the pressing pieces;

the two first connecting beams are respectively provided with at least two induction switches for detecting the position of a casting and sending signals to the PLC control system, one of the two rotating disks is provided with an induction plate, the rack is provided with a first proximity switch group and a second proximity switch group for detecting the position of the induction plate, the first proximity switch group and the second proximity switch group are symmetrically arranged about the central axis of the rotating disks, so that the induction plate can be detected by only one of the first proximity switch group and the second proximity switch group in one rotating process, the first proximity switch group and the second proximity switch group respectively comprise two proximity switches, the proximity switch which detects the induction plate firstly sends signals to the PLC control system when the induction plate rotates, the PLC control system controls the driving motor to decelerate and slow down the rotating speed of the rotating disks, and the proximity switch which detects the induction plate secondly sends signals to the PLC control system when the induction plate rotates, enabling a PLC control system to control the driving motor to stop and enable the rotating disc to stop rotating;

the rotating disc is provided with a collision block, the rack is provided with a limiting block, and the collision block collides with the limiting block when rotating to block the collision block and limit the rotating angle of the rotating disc.

Preferably, the pressing mechanism is any one of an oil cylinder, an air cylinder or an electric push rod.

Preferably, install two safety nets in the frame, two safety nets are located two one sides that the roll table was kept away from to the disc that rotates respectively, all offer the opening that is used for supplying the foundry goods to pass through on two safety nets.

Preferably, install two access doors in the frame, two access doors are located lower pipeline both sides respectively, the access door includes through hinge and frame articulated left door leaf and right door leaf, and be used for with upper bolt and lower bolt that left door leaf and right door leaf inserted tightly, all install the handle on left door leaf and the right door leaf.

According to the technical scheme, the invention has the beneficial effects that:

the turnover machine for the casting cleaning and detecting conveying line provided by the invention can be used for safely, efficiently and mechanically and automatically turning castings in the conveying line, so that the bottom of the castings which is difficult to detect and clean is turned to the top in the state before turning, all the inner and outer surfaces of the castings can be sufficiently cleaned and detected, the turned castings can be continuously conveyed in the conveying line through the roller conveying system, the requirement that the castings are cleaned and detected without falling down by the conveying line is met, the problems that the efficiency is low and safety accidents are easy to occur when the castings are manually turned are avoided, the labor intensity is reduced, the production efficiency is improved, the operation is convenient and flexible, the use is safe and reliable, and the requirement for automatic production of the castings can be met.

Drawings

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

FIG. 2 is a schematic side view of the present invention;

figure 3 is a schematic view of an access door of the present invention.

The labels in the figure are: 1. casting, 2, a rack, 3, a limiting wheel, 4, a first proximity switch group, 5, an induction plate, 6, a rotating disk, 7, a first connecting beam, 8, an induction switch, 9, a chain mounting ring, 10, a supporting wheel, 11, a lower roller way, 12, a collision block, 13, a limiting block, 14, a lower chain wheel group, 15, a safety net, 16, an access door, 1601, a hinge, 1602, a left door leaf, 1603, an upper bolt, 1604, a right door leaf, 1605, a lower bolt, 1606, a handle, 17, a double-row chain wheel, 18, a roller way motor, 19, a second proximity switch group, 20, a tensioning chain wheel, 21, a nut, 22, a chain fixing block, 23, a wheel group, an upper chain, 24, a second connecting beam, 25, a driving chain, 26, an upper roller way, 27, a pressing mechanism, 28, a mounting seat, 29, a pressing block, 30, a direction-changing wheel, 31, a driving chain wheel, 32, a driving motor, 33, a roller way piece, 34, and (5) discharging the workpiece from a roller way.

Detailed Description

Referring to the drawings, the specific embodiments are as follows:

the utility model provides a upset machine for foundry goods clearance, detection transfer chain, includes frame 2 and two rotating disc 6, install two pairs on the frame 2 and be used for supporting respectively two rotating disc 6's supporting wheel 10, supporting wheel 10 homoenergetic is all parallel to each other around self axis free rotation and all supporting wheel 10's axis, all has seted up the race with rotating disc 6 assorted on the outer circumference of all supporting wheel 10, and the race of two supporting wheels 10 of the same pair sets up relatively, and two rotating disc 6's outer circumference is pressed respectively and is established on the race groove bottom of a pair of supporting wheel 10, makes two rotating disc 6 homoenergetic freely rotate around self axis and the axis coincidence of two rotating disc 6 to establish the both ends face of rotating disc 6 along its axial degree of freedom with the restriction rotating disc 6 through the lateral wall card of supporting wheel 10 race, still install two spacing wheels 3 on the frame 2, the outer circumference of the limiting wheel 3 is pressed on the outer circumference of the rotating disk 6 to limit the displacement of the rotating disk 6 and prevent the rotating disk 6 from being separated from the wheel groove of the supporting wheel 10;

a chain mounting ring 9 is arranged on the end surface of one of the two rotating disks 6, the outer diameter of the chain mounting ring 9 is smaller than the outer diameter 6 of the rotating disk, and the central axis of the chain mounting ring 9 is superposed with the central axis of the rotating disc 6, two chain fixing blocks 22 are mounted on the outer circumference of the chain mounting ring 9, the frame 2 is also provided with a driving motor 32 for driving the driving chain 25 to move so as to drive the rotating disc 6 to rotate, the output end of the driving motor 32 is provided with a driving chain wheel 31, the driving chain 25 is meshed with the driving chain wheel 31, two ends of the driving chain 25 are wound around the outer circumference of the chain mounting ring 9 and are respectively connected with one chain fixing block 22, the two chain fixing blocks 22 are respectively provided with a nut 21 for adjusting the tightness degree of the driving chain 25, the frame 2 is also provided with a direction-changing wheel 30 for increasing the surrounding range of the driving chain 25 on the outer circumference of the chain mounting ring 9;

rectangular holes for allowing the castings 1 to pass through are formed in the two rotating discs 6, a lower roller way 11, an upper roller way 26, two first connecting beams 7 and two second connecting beams 24 are arranged between the two rotating discs 6, two ends of the lower roller way 11 are respectively installed on the inner walls of the rectangular holes of the two rotating discs 6, two ends of the upper roller way 26 are respectively installed on the inner walls, opposite to the inner walls where the lower roller way 11 is installed, of the rectangular holes of the two rotating discs 6, the lower roller way 11 and the upper roller way 26 are parallel to each other and symmetrically arranged about the central axis of the rotating discs 6, the two first connecting beams 7 are respectively located on two sides of the rectangular holes of the rotating discs 6, and two ends of each of the first connecting beam 7 and the second connecting beam 24 are respectively and fixedly connected with the two rotating discs 6;

one of the two first connecting beams 7 is provided with a roller way motor 18 and a tensioning sprocket 20, the output end of the roller way motor 18 is provided with a double-row sprocket 17, the end surface of one of the two rotating disks 6 is provided with a lower sprocket group 14 and an upper sprocket group 23, the roller way motor 18 drives the double-row sprocket 17 to rotate and drives the lower sprocket group 14 and the upper sprocket group 23 to rotate through chain transmission, the lower sprocket group 14 drives the lower roller way 11 to rotate through chain transmission, the upper sprocket group 23 drives the upper roller way 26 to rotate through chain transmission, and the tensioning sprocket 20 is used for tensioning the chain transmission between the double-row sprocket 17 and the upper sprocket group 23;

two pressing mechanisms 27 are arranged on one side of the upper roller way 26, which is far away from the lower roller way 11, the pressing mechanisms 27 are any one of oil cylinders, air cylinders or electric push rods, the second connecting beam 24 is provided with a mounting seat 28, the pressing mechanisms 27 are hinged with the mounting seat 28, pressing pieces 29 are arranged on all the pressing mechanisms 27, and the pressing pieces 29 are driven by the pressing mechanisms 27 to move towards the lower roller way 11 and penetrate through a gap between two adjacent rollers in the upper roller way 26, so that the pressing pieces 29 press the casting 1 on the lower roller way 11;

the two first connecting beams 7 are respectively provided with two induction switches 8 which are used for detecting the position of the casting 1 and sending signals to a PLC control system, one of the two rotating disks 6 is provided with an induction plate 5, the rack 2 is provided with a first proximity switch group 4 and a second proximity switch group 19 which are used for detecting the position of the induction plate 5, the first proximity switch group 4 and the second proximity switch group 19 are symmetrically arranged about the central axis of the rotating disks 6, so that the induction plate 5 can be detected by only one of the first proximity switch group 4 and the second proximity switch group 19 in one rotating process, the first proximity switch group 4 and the second proximity switch group 19 both comprise two proximity switches, the induction plate 5 is detected to send signals to the PLC control system in advance when rotating, the PLC control system controls the driving motor 32 to decelerate and slow down the rotating speed of the rotating disks 6, when the induction plate 5 rotates, a proximity switch of the induction plate 5 is detected to send a signal to a PLC control system, so that the PLC control system controls the driving motor 32 to stop and the rotating disc 6 stops rotating;

the rotating disc 6 is provided with a collision block 12, the frame 2 is provided with a limit block 13, and the collision block 12 collides with the limit block 13 to block the collision block 12 and limit the rotating angle of the rotating disc 6 when the collision block 12 rotates.

Install two safety nets 15 on the frame 2, two safety nets 15 are located two one sides that roll table 11 was kept away from to two rotating disc 6 respectively, all offer the opening that is used for supplying foundry goods 1 to pass through on two safety nets 15.

Install two access doors 16 in the frame 2, two access doors 16 are located rollgang 11 both sides respectively, access door 16 includes through hinge 1601 and frame 2 articulated left door leaf 1602 and right door leaf 1604, and be used for with left door leaf 1602 and right door leaf 1604 insert tight last bolt 1603 and lower bolt 1605, all install handle 1606 on left door leaf 1602 and the right door leaf 1604.

When the turnover machine provided by the invention works, the turnover machine is arranged between the workpiece inlet roller way 33 and the workpiece outlet roller way 34, so that two ends of the lower roller way 11 are respectively aligned with the workpiece inlet roller way 33 and the workpiece outlet roller way 34, the castings 1 pass through the rectangular holes of the rotating disc 6 from the workpiece inlet roller way 33 and are transported to the lower roller way 11 through synchronous rotation of the rollers of the lower roller way 11 and the rollers of the workpiece inlet roller way 33, after the sensing switches 8 detect the castings 1, signals are sent to the PLC control system, the PLC controls the pressing mechanism 27 to drive the pressing block 29 to move towards the lower roller way 11, the castings 1 are pressed on the lower roller way 11, the driving motor 32 is started and drives the rotating disc 6 to rotate 180 degrees through the driving chain 25, the upper roller way 26 is turned to the position, aligned with the workpiece inlet roller way 33 and the workpiece outlet roller way 34, when the upper roller way 26 is turned over to the lower roller way 11, the castings 1 are driven to be turned over, and the bottoms of the castings, so that all the inner and outer surfaces of the casting 1 can be cleaned and detected; after the upper roller way 26 is aligned with the workpiece inlet roller way 33 and the workpiece outlet roller way 34, the pressing mechanism 27 drives the pressing piece block 29 to reset and separate from the casting 1, so that the turned casting 1 is positioned on the upper roller way 26, the casting 1 passes through the rectangular hole of the rotating disc 6 from the upper roller way 26 and is transferred to the workpiece outlet roller way 34 through the synchronous rotation of the rollers of the upper roller way 26 and the rollers of the workpiece outlet roller way 34, and the turned casting 1 is continuously conveyed in the conveying line; at this moment, the next casting 1 enters and is sent to the upper roller way 26, the pressing mechanism 27 drives the pressing piece block 29 to move again, the casting 1 is jacked up and is jacked on the lower roller way 11, then the driving motor 32 drives the rotating disc 6 to rotate, so that the lower roller way 11 and the upper roller way 26 are turned over again, the lower roller way 11 is made to return to the position aligned with the feeding roller way 33 and the discharging roller way 34, the turning of the casting 1 jacked on the lower roller way 11 is realized, through repeating the working process, the turning machine can sequentially, safely, efficiently and mechanically and automatically turn over the casting 1 in the conveying line, and the casting 1 in the conveying line can be fully cleaned and detected.

Claims

1. The utility model provides a upset machine that is used for foundry goods clearance, detects transfer chain which characterized in that: including frame (2) and two rotating disc (6), install two pairs on frame (2) and be used for supporting respectively supporting wheel (10) of two rotating disc (6), supporting wheel (10) homoenergetic is all parallel to each other around self axis free rotation and the axis of all supporting wheel (10), all seted up on the outer circumference of supporting wheel (10) with rotating disc (6) assorted race, the race of two supporting wheels (10) of same pair sets up relatively, the outer circumference of two rotating disc (6) is pressed respectively and is established on the race groove bottom of a pair of supporting wheel (10), make two rotating disc (6) homoenergetic around self axis free rotation and the coincidence of the axis of two rotating disc (6), and establish the both ends face of rotating disc (6) with the restriction rotating disc (6) along its axial degree of freedom through the lateral wall card of supporting wheel (10) race, the rack (2) is also provided with a plurality of limiting wheels (3), the outer circumferences of the limiting wheels (3) are pressed on the outer circumference of the rotating disc (6) to limit the displacement of the rotating disc (6) and prevent the rotating disc (6) from being separated from the wheel groove of the supporting wheel (10);

install chain collar (9) on the terminal surface of one of them of two rotating disc (6), the external diameter of chain collar (9) is less than rotating disc's external diameter (6), and the axis of chain collar (9) coincides with the axis of rotating disc (6), installs two chain fixed block (22) on the outer circumference of chain collar (9), still install on frame (2) and be used for driving drive chain (25) motion in order to drive rotating disc (6) pivoted driving motor (32), drive sprocket (31) is installed to the output of driving motor (32), drive chain (25) and drive sprocket (31) meshing, the outer circumference of chain collar (9) is all encircleed at the both ends of drive chain (25) and is connected with a chain fixed block (22) respectively, all is equipped with nut (21) that are used for adjusting drive chain (25) elasticity degree on two chain fixed block (22), the rack (2) is also provided with a direction changing wheel (30) for increasing the surrounding range of the driving chain (25) on the outer circumference of the chain mounting ring (9);

rectangular holes for the castings (1) to pass through are formed in the two rotating discs (6), a lower roller way (11), an upper roller way (26), two first connecting beams (7) and at least one second connecting beam (24) are arranged between the two rotating discs (6), two ends of the lower roller way (11) are respectively arranged on the inner walls of the rectangular holes of the two rotating discs (6), two ends of the upper roller way (26) are respectively arranged on the inner walls of the rectangular holes of the two rotating discs (6) opposite to the inner wall of the lower roller way (11), the lower roller way (11) and the upper roller way (26) are parallel to each other and are symmetrically arranged about the central axis of the rotating discs (6), the two first connecting beams (7) are respectively positioned at two sides of the rectangular hole of the rotating disc (6), both ends of the first connecting beam (7) and the second connecting beam (24) are respectively fixedly connected with the two rotating discs (6);

a roller way motor (18) and a tensioning chain wheel (20) are mounted on one of the two first connecting beams (7), a double-row chain wheel (17) is mounted at the output end of the roller way motor (18), a lower chain wheel set (14) and an upper chain wheel set (23) are mounted on the end surface of one of the two rotating disks (6), the roller way motor (18) drives the double-row chain wheel (17) to rotate and drives the lower chain wheel set (14) and the upper chain wheel set (23) to rotate through chain transmission, the lower chain wheel set (14) drives the lower roller way (11) to rotate through chain transmission, the upper chain wheel set (23) drives the upper roller way (26) to rotate through chain transmission, and chain transmission tensioning between the double-row chain wheel (17) and the upper chain wheel set (23) is realized through the tensioning chain wheel (20);

at least two pressing mechanisms (27) are arranged on one side, away from the lower roller way (11), of the upper roller way (26), mounting seats (28) are arranged on the second connecting beam (24), the pressing mechanisms (27) are hinged to the mounting seats (28), pressing pieces (29) are mounted on all the pressing mechanisms (27), the pressing pieces (29) are driven by the pressing mechanisms (27) to move towards the lower roller way (11) and penetrate through gaps between two adjacent rollers in the upper roller way (26), and the castings (1) are pressed on the lower roller way (11) by the pressing pieces (29);

all install two at least induction switches (8) that are used for detecting foundry goods (1) position and send signal to PLC control system on two first connecting beam (7), install tablet (5) on one of them of two carousel (6), install first proximity switch group (4) and second proximity switch group (19) that are used for detecting tablet (5) position on frame (2), first proximity switch group (4) and second proximity switch group (19) are about the axis symmetry setting of carousel (6) makes tablet (5) only can be detected by one of them in first proximity switch group (4) and second proximity switch group (19) in a rotation process, and first proximity switch group (4) and second proximity switch group (19) all include two proximity switches, detects the proximity switch of tablet (5) earlier when rotating through tablet (5) and sends signal to PLC control system, enabling a PLC control system to control the driving motor (32) to decelerate and slow down the rotating speed of the rotating disc (6), and detecting a proximity switch of the induction plate (5) to send a signal to the PLC control system when the induction plate (5) rotates, so that the PLC control system controls the driving motor (32) to stop and the rotating disc (6) to stop rotating;

install on the rotating disc (6) and hit piece (12), install stopper (13) on frame (2), collide with stopper (13) when rotating through hitting piece (12) and in order to block to hit piece (12) and restrict the turned angle who rotates disc (6).

2. The turnover machine for the casting cleaning and detecting conveying line according to claim 1, wherein the turnover machine comprises: the pressing mechanism (27) is any one of an oil cylinder, an air cylinder or an electric push rod.

3. The turnover machine for the casting cleaning and detecting conveying line according to claim 1, wherein the turnover machine comprises: install two safety nets (15) on frame (2), two safety nets (15) are located two one side that roll table (11) were kept away from down in rotation disc (6) respectively, all offer the opening that is used for supplying foundry goods (1) to pass through on two safety nets (15).

4. The turnover machine for the casting cleaning and detecting conveying line according to claim 1, wherein the turnover machine comprises: install two access doors (16) on frame (2), two access doors (16) are located rollgang (11) both sides down respectively, access door (16) include through hinge (1601) and frame (2) articulated left door leaf (1602) and right door leaf (1604), and be used for with left door leaf (1602) and right door leaf (1604) insert tight last bolt (1603) and lower bolt (1605), all install handle (1606) on left door leaf (1602) and right door leaf (1604).