A welding device for recycling waste frames suitable for vehicle modification

Abstract

The invention provides a welding device for recycling waste frames suitable for vehicle modification, a flipping mechanism, a reducer is installed on one side of the flipping mechanism, a first motor is installed on one end of the reducer, a connecting seat is connected to one side of the flipping mechanism, a transmission component for adjusting the clamping width is connected to the top of the connecting seat, the transmission component comprises a limit plate, a main beam, a cross bar, a reset spring, a screw rod, a main gear, a driven gear, a transmission rod, a sleeve, a main bevel gear and a secondary bevel gear, the driven gear drives the main bevel gear to rotate through the transmission rod, the main bevel gear drives the secondary bevel gear to rotate by meshing with the secondary bevel gear, the secondary bevel gear drives the screw rod to rotate and threads are provided inside two cross bars, so that the two cross bars move back to back, when the limit plate is subjected to the maximum gravity of the frame, the pressure applied causes the two cross bars to drive the clamping rods to move back to back through gear transmission, thereby adjusting the width of the clamped vehicle.

Description

Technical Field

[0001] The invention relates to the technical field of automobiles, and in particular to a welding device for recycling waste frames suitable for vehicle modification. Background Art

[0002] In the process of vehicle manufacturing, the first step is to manufacture the frame of the whole vehicle. The frame must have sufficient strength and rigidity to bear the load of the car and the impact from the wheels. The frame needs to be welded to improve its own strength and rigidity to protect the passengers. The welding frame is mainly reflected in the stability of the vehicle during the welding process, and welding is performed at different positions to achieve the effect of improving the strength and rigidity of the frame. Technical inspiration for frame welding;

[0003] Research on frame welding found the following problems:

[0004] During the process of moving the frame to the fixture during frame welding, the frame is hoisted to the fixture by a crane and then directly fixed by the fixture. Due to the different widths of different vehicles, when the fixture fixes frames of different widths, it is not possible to clamp and fix wider or narrower vehicles, resulting in the inability to continue the vehicle welding process or the limitations of the fixture, thereby failing to achieve the purpose of improving the strength and rigidity of the frame;

[0005] At present, CN108115347A in the prior art discloses a reversible automobile frame assembly welding fixture, which discloses a fixture for an automobile frame during welding. When the frame falls from above, one end of the frame is attached to the baffle plate and falls onto the slope of the supporting vertical plate. By limiting the end of the frame, the corresponding position on the frame can accurately fall onto the clamping device, thereby facilitating the clamping of the frame.

[0006] The present invention can mainly solve the problem that when a fixing device fixes vehicle frames of different widths, a wider or narrower vehicle cannot be clamped and fixed. Summary of the invention

[0007] In order to solve the above technical problems, the present invention provides a welding device for recycling waste frames suitable for vehicle modification to solve the problems described in the above background technology.

[0008] The purpose and efficacy of the scrap frame recycling welding equipment suitable for vehicle modification of the present invention are achieved by the following specific technical means: a scrap frame recycling welding equipment suitable for vehicle modification comprises a flipping mechanism, a reducer is installed on one side of the flipping mechanism, a first motor is installed on one end of the reducer, a connecting seat is connected to one side of the flipping mechanism, a transmission assembly for adjusting the clamping width is connected to the top of the connecting seat, the transmission assembly comprises a limit plate, a main beam, a cross bar, a return spring, a screw rod, a main gear, a driven gear, a transmission rod, a sleeve, a main bevel gear and a secondary bevel gear, a limit plate is arranged on the top of the main beam, a main gear is installed on the inner wall of the main beam, a cross bar is arranged on one side of the main beam, a sleeve is arranged on one end of the cross bar, a transmission rod is arranged on one side of the sleeve, the driven gear and the main bevel gear are respectively connected at both ends of the transmission rod, a screw rod is arranged inside the sleeve, a secondary bevel gear is arranged on the outer side of the screw rod, and a return spring is arranged on one side of the secondary bevel gear.

[0009] Furthermore, a gear groove is provided on the side of the limit plate away from the flipping mechanism, and the rack inside the gear groove is inclined downward by thirty-five degrees and meshes with the main gear, and the main gear meshes vertically with the driven gear, and the tooth pitch of the main gear is greater than the tooth pitch of the driven gear.

[0010] Furthermore, the two cross bars are arranged in a mirror image, and threads matching the screw rod are provided inside the two cross bars, and a clamping assembly for limiting the position of the frame is installed on the top of the cross bar.

[0011] Furthermore, the main bevel gear is meshed with the auxiliary bevel gear, and return springs are installed on both sides of the auxiliary bevel gear, and the other sides of the two return springs are connected to one end of the cross bar through a rotating shaft.

[0012] Furthermore, four through holes matching the limit plates are provided at the edges of both ends of the upper surface of the main beam, and four through holes matching the cross bars are provided on both sides of the main beam.

[0013] Furthermore, the clamping assembly includes a clamping rod, a second motor, a connecting block, a worm, a worm gear, a clamping block, a main slider, a secondary slider, a connecting roller, an airbag, a support block, a main limit block and a secondary limit block. A second motor is installed on one side of the clamping rod, and the output end of the second motor is connected to the worm. A connecting roller is arranged inside the clamping rod, a worm gear is arranged at the center of the connecting roller, a connecting block is connected to the outer side surface of the connecting roller, a clamping block is connected to the bottom of the connecting block, a main slider is arranged on one side of the bottom of the clamping block, a main limit block is connected to the top of the main slider, a secondary slider is arranged on one side of the bottom of the main slider, a secondary slider is connected to the top of the secondary slider, the interior of the connecting block is filled with an airbag, and a support block is installed on the outer side surface of the airbag.

[0014] Furthermore, the connection block is arranged in the shape of a book title, and the included angle is 130 degrees, the clamping rod is arranged in the shape of an arrow, and the vertical end of the arrow is located at the bottom of the connection block;

[0015] Furthermore, the clamp block is arranged in a pentagonal shape, and one side of the clamp block is arranged in an inclined shape, the inclined surface is arranged in an open shape, and three circular through holes are opened on one side of the bottom of the clamp block adjacent to the inclined surface, the support block is arranged in a semicircular shape at the circular through holes at the bottom of the clamp block, and when the support block is located outside the clamp block, it is located on the same horizontal line as the inclined surface of the clamp block;

[0016] Furthermore, the main slider and the auxiliary slider are embedded in the inclined surface at the bottom of the clamping block in a stepped manner;

[0017] Furthermore, the two connecting blocks, the worm gear, the clamping block, the main slider, the auxiliary slider, the connecting roller, the airbag, the supporting block, the main limit block and the auxiliary limit block are all symmetrically arranged with the worm as the center point;

[0018] Beneficial effects:

[0019] 1. The automobile frame is lifted by a crane to the top of the beam, and then the crane lowers the frame. At this time, the crane bears all the gravity of the frame. When the frame drops to the inclined surface of the limit plates at both ends of the beam, the gravity of the frame falls entirely on the limit plates. The gravity on the limit plates increases instantly, and the limit plates move downward through the through holes on the upper surface of the beam under the action of gravity. While the limit plates move downward, they drive the main gear to rotate through the gear groove on one side. The gear groove is inclined downward by the internal rack at 30 degrees, which speeds up the rotation rate of the main gear. The main gear is driven to rotate faster and the pitch is greater than that of the driven gear, thereby improving the rotation efficiency of the driven gear through gear transmission.

[0020] 2. The driven gear drives the main bevel gear to rotate through the transmission rod, and the main bevel gear drives the secondary bevel gear to rotate by meshing with it. The secondary bevel gear drives the screw to rotate and passes through the two cross bars, which are provided with threads inside, so that the two cross bars move in reverse. When the limit plate is subjected to the maximum gravity of the frame, the pressure it receives drives the two cross bars to drive the clamping rods to move in reverse through the gear transmission, thereby adjusting the width of the clamped vehicle;

[0021] 3. When the instantaneous increased pressure on the two limit plates disappears and a balance is formed, the limit plates improve the moving efficiency of the cross bar through gear transmission, and the two cross bars drive the two clamping rods to move toward each other, and then the two sides of the frame are nested between the two connecting blocks, and then the second motor is started, and the second motor drives the worm to rotate. The two worm wheels are symmetrically arranged with the worm as the center, and the two worm wheels are meshed with the worm. When the worm rotates, it drives the two worm wheels to rotate. The rotation of the two worm wheels drives the connecting blocks to rotate. The two connecting blocks are arranged in the shape of a book title to prevent the presence of baffles on both sides of the frame from being inconvenient for clamping.

[0022] 4. The two connecting blocks rotate to fit on both sides of the frame and clamp it. The connection blocks are driven to rotate in a circle by the rotation of the worm gear. The connecting blocks squeeze the auxiliary slider. When the auxiliary slider moves toward the inside of the clamp block under pressure, it pushes the main slider to enter the inside of the clamp block. The auxiliary slider pushes the main slider into the inside of the clamp block and squeezes the airbag at the same time. The airbag pushes the support block through the through hole at the bottom of the clamp block to move to its outer side surface under pressure. When the support block moves to the outer side of the clamp block, it is on the same horizontal line with the inclined surface of the bottom of the clamp block, so that the support block fits the frame and clamps it. The support block is arranged in a semicircular shape, so that the point where the support block fits the frame, the point where the support block is connected to the airbag, and the point where the clamp block fits the frame form a triangle, thereby improving the stability of the clamp block clamping the frame. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0024] Figure 2 This is a schematic diagram of the split structure of the crossbeam of the present invention;

[0025] Figure 3 This is a schematic diagram of the crossbeam structure of the present invention;

[0026] Figure 4 This is a schematic diagram of the connection structure between the main gear and the driven gear of the present invention;

[0027] Figure 5 It is a schematic diagram of the cross-sectional structure of the sleeve of the present invention;

[0028] Figure 6 This is a schematic diagram of the worm and worm gear connection structure of the present invention;

[0029] Figure 7 This is a schematic diagram of the connecting roller structure of the present invention;

[0030] Figure 8 This is a schematic diagram of the cross-sectional structure of the clamp block of the present invention;

[0031] Fig. 9 It is a schematic diagram of the split structure of the clamp block of the present invention.

[0032] Figure 1-9 In the figure, the corresponding relationship between the component names and the figure numbers is as follows:

[0033] 1. Flipping mechanism; 101. First motor; 102. Reducer; 2. Connecting seat; 201. Limiting plate; 3. Main beam; 301. Cross bar; 302. Return spring; 303. Screw rod; 304. Main gear; 305. Driven gear; 306. Transmission rod; 307. Sleeve; 308. Main bevel gear; 309. Sub bevel gear; 4. Clamping rod; 401. Second motor; 402. Connecting block; 403. Worm; 404. Worm wheel; 405. Clamping block; 406. Main slider; 407. Sub slider; 408. Connecting roller; 409. Airbag; 410. Support block; 411. Main limiting block; 412. Sub limiting block. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0035] As attached Figure 1 To Attachment Fig. 9 As shown:

[0036] Example 1

[0037] A welding device for recycling a waste frame suitable for vehicle modification comprises a turning mechanism 1, a reducer 102 is installed on one side of the turning mechanism 1, a first motor 101 is installed on one end of the reducer 102, a connecting seat 2 is connected to one side of the turning mechanism 1, a transmission assembly for adjusting the clamping width is connected to the top of the connecting seat 2, and the transmission assembly comprises a limit plate 201, a main beam 3, a cross bar 301, a return spring 302, a screw rod 303, a main gear 304, a driven gear 305, a transmission rod 306, a sleeve 307, a main bevel gear 308 and a secondary bevel gear 309;

[0038] A limit plate 201 is provided on the top of the main beam 3, a main gear 304 is installed on the inner wall of the main beam 3, a cross bar 301 is provided on one side of the main beam 3, a sleeve 307 is provided at one end of the cross bar 301, a transmission rod 306 is provided on one side of the sleeve 307, and two ends of the transmission rod 306 are respectively connected to a driven gear 305 and a main bevel gear 308, a screw rod 303 is provided inside the sleeve 307, a secondary bevel gear 309 is provided on the outer side of the screw rod 303, and a return spring 302 is installed on one side of the secondary bevel gear 309;

[0039] A gear groove is provided on one side of the limit plate 201 away from the flip mechanism 1. The rack inside the gear groove is tilted downward by 35 degrees and meshes with the main gear 304. The main gear 304 meshes vertically with the driven gear 305, and the pitch of the main gear 304 is greater than the pitch of the driven gear 305.

[0040] The two cross bars 301 are arranged in a mirror image, and the inside of the two cross bars 301 is provided with threads matching the screw rod 303, and the top of the cross bars 301 is installed with a clamping component for limiting the position of the frame;

[0041] The main bevel gear 308 is meshed with the auxiliary bevel gear 309, and return springs 302 are installed on both sides of the auxiliary bevel gear 309, and the other sides of the two return springs 302 are connected to one end of the crossbar 301 through a rotating shaft;

[0042] Among them, four through holes matching the limit plates 201 are opened at the edges of both ends of the upper surface of the main beam 3, and four through holes matching the crossbars 301 are opened on both sides of the main beam 3;

[0043] The automobile frame is lifted by the crane to the top of the cross beam 3, and then the crane lowers the frame. At this time, the crane bears all the gravity of the frame. When the frame falls to the inclined surface of the limit plates 201 at both ends of the cross beam 3, the gravity of the frame falls entirely on the limit plates 201. The gravity on the limit plates 201 increases instantly, and the limit plates 201 move downward through the through holes on the upper surface of the cross beam 3 under the action of gravity. While the limit plates 201 move downward, they drive the main gear 304 to rotate through the gear groove on one side. The gear groove is set to be inclined downward by 30 degrees through the internal rack, so that the rotation rate of the main gear 304 is accelerated. The main gear 304 is driven by the increased rotation rate and the pitch is greater than the driven gear 305, thereby improving the rotation efficiency of the driven gear 305 through gear transmission. At the same time, the driven gear 305 drives the main bevel gear 308 to rotate through the transmission rod 306, and the main bevel gear 308 drives the auxiliary bevel gear 309 by meshing with it. When it rotates, the secondary bevel gear 309 drives the screw rod 303 to rotate and the two cross bars 301 are provided with threads inside, so that the two cross bars 301 move in opposite directions. The two cross bars 301 pull the return spring 302 while moving. As the pressure of the frame on the limit plates 201 at both ends disappears, the limit plates 201 at both ends balance the gravity applied by the frame. At this time, the limit plates 201 at both ends push the frame to move upward. The limit plates 201 drive the main gear 304 to rotate in the opposite direction through the gear groove. The main gear 304 also drives the driven gear 305 to rotate in the opposite direction. The driven gear 305 drives the main bevel gear 308 to rotate in the opposite direction through the transmission rod 306. The secondary bevel gear 309 drives the screw rod 303 to rotate in the opposite direction, so that the two cross bars 301 move towards each other. While the cross bars 301 move towards each other, the return spring 302 increases the speed at which the two cross bars 301 move toward the inside of the sleeve 307.

[0044] Example 2

[0045] The present embodiment is different from the embodiment 1 in that the clamping assembly includes a clamping rod 4, a second motor 401, a connecting block 402, a worm 403, a worm wheel 404, a clamping block 405, a main slider 406, an auxiliary slider 407, a connecting roller 408, an airbag 409, a supporting block 410, a main limit block 411 and an auxiliary limit block 412, a second motor 401 is installed on one side of the clamping rod 4, the output end of the second motor 401 is connected to the worm 403, a connecting roller 408 is arranged inside the clamping rod 4, and the connecting roller 408 is arranged inside the clamping rod 4. A worm gear 404 is arranged at the center of 8, a connecting block 402 is connected to the outer side of the connecting roller 408, a clamping block 405 is connected to the bottom of the connecting block 402, a main slider 406 is arranged on one side of the bottom of the clamping block 405, a main limit block 411 is connected to the top of the main slider 406, a secondary slider 407 is arranged on one side of the bottom of the main slider 406, a secondary limit block 412 is connected to the top of the secondary slider 407, an air bag 409 is filled inside the connecting block 402, and a supporting block 410 is installed on the outer side of the air bag 409;

[0046] The connection block 402 is arranged in the shape of a book title, and the included angle is 130 degrees;

[0047] The worm wheel 404 is meshed with the worm 403;

[0048] The clamp block 405 is pentagonal, and one side of the clamp block 405 is inclined, the inclined surface is open, and three circular through holes are opened on one side of the bottom of the clamp block 405 adjacent to the inclined surface. The support block 410 is semicircular and arranged at the circular through holes at the bottom of the clamp block 405. When the support block 410 is located outside the clamp block 405, it is located on the same horizontal line as the inclined surface of the clamp block 405.

[0049] The main slider 406 and the auxiliary slider 407 are embedded in the inclined surface at the bottom of the clamping block 405 in a stepped manner;

[0050] Among them, the two connecting blocks 402, the worm gear 404, the clamping block 405, the main slider 406, the auxiliary slider 407, the connecting roller 408, the airbag 409, the supporting block 410, the main limit block 411 and the auxiliary limit block 412 are all symmetrically arranged with the worm 403 as the center point;

[0051] The clamping rod 4 is arranged in an arrow shape, and the vertical end of the arrow is located at the bottom of the connecting block 402;

[0052] When the vehicle frame is lifted to the limit plate 201 by the crane, the pressure on the limit plate 201 increases instantly, causing the two cross bars 301 to move back to the outer side of the main beam 3. The two cross bars 301 move back to back and drive the two clamping rods 4 to move. When the instantaneous increased pressure on the two limit plates 201 disappears and a balance is formed, the limit plate 201 improves the movement efficiency of the cross bars 301 through gear transmission, and the two cross bars 301 drive the two clamping rods 4 to move toward each other, and then the two sides of the vehicle frame are nested between the two connecting blocks 402, and then the second motor 401 is started, and the second motor 401 drives The worm 403 rotates, and two worm wheels 404 are symmetrically arranged with the worm 403 as the center, and the two worm wheels 404 are meshed with the worm 403. The worm 403 rotates and drives the two worm wheels 404 to rotate. The two worm wheels 404 rotate and drive the connecting block 402 to rotate. The two connecting blocks 402 are arranged in the shape of a book title to prevent baffles on both sides of the frame from being inconvenient to clamp. The two connecting blocks 402 rotate to fit the two sides of the frame and clamp it. The worm wheel 404 rotates and drives the connecting block 402 to rotate in a ring, and the connecting block 402 squeezes the auxiliary slider 407. When the auxiliary slider 407 is pressed to move toward the inside of the clamp block 405, it pushes the main slider 406 to enter the inside of the clamp block 405. The auxiliary slider 407 pushes the main slider 406 to enter the inside of the clamp block 405 and squeezes the airbag 409. The airbag 409 is pressed to push the support block 410 to move to its outer side through the bottom through hole of the clamp block 405. When the support block 410 moves to the outer side of the clamp block 405, it is located on the same horizontal line as the inclined surface at the bottom of the clamp block 405, so that the support block 410 fits the frame and clamps it. The support block 410 is set in a semicircular shape, so that the support block The point where 410 is attached to the frame, the point where the support block 410 is connected to the airbag 409, and the point where the clamp block 405 is attached to the frame form a triangle, thereby improving the stability of the clamp block 405 clamping the frame. When welding is completed, the second motor 401 drives the worm 403 to rotate in the opposite direction, and the two worm gears 404 drive the two connecting blocks 402 to return to the initial state. The pressure on the auxiliary slider 407 during the rotation of the connecting block 402 disappears, and the auxiliary slider 407 drives 406 to move downward to reset through the action of gravity. At this time, the pressure on the airbag 409 disappears, pulling the support block 410 back to the initial state.

[0053] The embodiments of the present invention are given for the purpose of illustration and description, and are not intended to be exhaustive or to limit the invention to the disclosed forms. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are selected and described in order to better illustrate the principles and practical applications of the present invention and to enable those of ordinary skill in the art to understand the present invention and thereby design various embodiments with various modifications suitable for specific uses.

Claims

1. A welding device for recycling waste frames suitable for vehicle modification, comprising a turning mechanism (1), characterized in that: A reducer (102) is installed on one side of the flipping mechanism (1), a first motor (101) is installed on one end of the reducer (102), a connecting seat (2) is connected to one side of the flipping mechanism (1), a transmission assembly for adjusting the clamping width is connected to the top of the connecting seat (2), and the transmission assembly comprises a limit plate (201), a main beam (3), a crossbar (301), a return spring (302), a screw (303), a main gear (304), a driven gear (305), a transmission rod (306), a sleeve (307), a main bevel gear (308) and a secondary bevel gear (309); A limit plate (201) is provided on the top of the main beam (3), a main gear (304) is installed on the inner wall of the main beam (3), a cross bar (301) is provided on one side of the main beam (3), a sleeve (307) is provided on one end of the cross bar (301), a transmission rod (306) is provided on one side of the sleeve (307), two ends of the transmission rod (306) are respectively connected to a driven gear (305) and a main bevel gear (308), a lead screw (303) is provided inside the sleeve (307), a secondary bevel gear (309) is provided on the outer side of the lead screw (303), and a return spring (302) is installed on one side of the secondary bevel gear (309); The two cross bars (301) are arranged in a mirror image, and threads matching the screw rod (303) are provided inside the two cross bars (301), and a clamping assembly for limiting the position of the frame is installed on the top of the cross bars (301); The clamping assembly comprises a clamping rod (4), a second motor (401), a connecting block (402), a worm (403), a worm wheel (404), a clamping block (405), a main slider (406), a secondary slider (407), a connecting roller (408), an airbag (409), a supporting block (410), a main limit block (411) and a secondary limit block (412); the second motor (401) is mounted on one side of the clamping rod (4); the worm (403) is connected to the output end of the second motor (401); a connecting roller (408) is arranged inside the clamping rod (4); the center of the connecting roller (408) is A worm gear (404) is provided at the connecting roller (408), the outer side surface of the connecting roller (408) is connected to the connecting block (402), the bottom of the connecting block (402) is connected to the clamping block (405), a main slider (406) is provided on one side of the bottom of the clamping block (405), the top of the main slider (406) is connected to the main limit block (411), a secondary slider (407) is provided on one side of the bottom of the main slider (406), the top of the secondary slider (407) is connected to the secondary limit block (412), the interior of the connecting block (402) is filled with an air bag (409), and a support block (410) is installed on the outer side surface of the air bag (409); The connecting block (402) is arranged in the shape of a book title, and the included angle is 130 degrees; the clamping rod (4) is arranged in the shape of an arrow, and the vertical end of the arrow is located at the bottom of the connecting block (402); The clamping block (405) is arranged in a pentagonal shape, and one side thereof is arranged in an inclined shape, the inclined surface is arranged in an open shape, three circular through holes are opened on a side of the bottom of the clamping block (405) adjacent to the inclined surface, the supporting block (410) is arranged in a semicircular shape at the circular through holes at the bottom of the clamping block (405), and when the supporting block (410) is located outside the clamping block (405), it is located on the same horizontal line as the inclined surface of the clamping block (405); The main sliding block (406) and the auxiliary sliding block (407) are embedded in the inclined surface at the bottom of the clamping block (405) in a stepped manner; The two connecting blocks (402), the worm wheel (404), the clamping block (405), the main slider (406), the auxiliary slider (407), the connecting roller (408), the airbag (409), the supporting block (410), the main limit block (411) and the auxiliary limit block (412) are all symmetrically arranged with the worm (403) as the center point.

2. The welding equipment for recycling waste frames suitable for vehicle modification according to claim 1 is characterized in that: A gear groove is provided on one side of the limit plate (201) away from the flipping mechanism (1), wherein a rack inside the gear groove is arranged to be inclined downward at 35 degrees and meshes with the main gear (304), wherein the main gear (304) meshes vertically with the driven gear (305), and the tooth pitch of the main gear (304) is greater than the tooth pitch of the driven gear (305).

3. The welding equipment for recycling waste frames suitable for vehicle modification according to claim 1 is characterized in that: The main bevel gear (308) is meshed with the auxiliary bevel gear (309), and return springs (302) are installed on both sides of the auxiliary bevel gear (309), and the other sides of the two return springs (302) are connected to one end of the crossbar (301) through a rotating shaft.

4. The welding equipment for recycling scrap frames suitable for vehicle modification according to claim 1 is characterized in that: Four through holes matching the limit plates (201) are provided at the edges of both ends of the upper surface of the main beam (3), and four through holes matching the cross bars (301) are provided on both sides of the main beam (3).

Images