CN214263716U

CN214263716U - High-precision correction device for welding ring machining

Info

Publication number: CN214263716U
Application number: CN202023079958.4U
Authority: CN
Inventors: 许志国; 许伟
Original assignee: Nanjing Lizhixing Welding Material Co ltd
Current assignee: Nanjing Lizhixing Welding Material Co ltd
Priority date: 2020-12-18
Filing date: 2020-12-18
Publication date: 2021-09-24
Anticipated expiration: 2030-12-18

Abstract

The utility model relates to a weld high accuracy orthotic devices for ring processing, it includes the board, set gradually the thread feeding mechanism on the board lateral wall, whole round mechanism is including installing the wire winding arc piece on the board lateral wall and being located the wire winding arc piece one side around the ring, the lateral wall of board and the top that is located whole round mechanism are equipped with disconnected silk mechanism, still including setting up the plastic mechanism that just is located whole round mechanism one side on the board, plastic mechanism is including the support charging tray that is used for correcting the subassembly that flattens of welding ring and is located the subassembly below that flattens, be equipped with the installation component that is used for fixed support charging tray on the board, be equipped with the guide subassembly that is used for with the leading-in support charging tray of welding ring on the board. This application welds the ring and corrects the effect in order to improve machining efficiency through replacing artifical manual collection.

Description

High-precision correction device for welding ring machining

Technical Field

The application relates to the field of welding ring machining, in particular to a high-precision correction device for welding ring machining.

Background

The welding ring is a welding tool, is used for connecting the metal component that intensity is higher, and the material of welding ring usually is the lead-tin welding wire, and the production technology of welding ring generally includes: smelting metal, extruding, drawing wire, making ring, binding sheet, making mould and other steps. In the ring making process of the welding ring, the welding ring is generally processed by a welding ring forming machine, a feeding mechanism is used for conveying a welding wire into an arc-shaped guide rail to be coiled into a ring shape, an upper blade is used for cutting downwards, the welding ring falls off, and two ends of the cut welding ring are distributed in a staggered mode and need to be pressed flatly.

Among the correlation technique, flattening of butt welding ring needs the manual work to carry the flattening device with cutting the welding ring that drops and flattens, because the welding ring is batch production every day, adopts artifical transport to weld the ring, and is consuming time hard, has reduced production efficiency.

SUMMERY OF THE UTILITY MODEL

In order to improve the artifical problem that welds ring consuming time and difficultly of carrying, this application provides a weld ring processing and use high accuracy correcting device.

The application provides a weld ring processing and use high accuracy correcting unit adopts following technical scheme:

the utility model provides a weld high accuracy orthotic devices for ring processing, includes the board, sets gradually thread feeding mechanism, the whole round of mechanism on the board lateral wall, whole round of mechanism is including installing the wire winding arc piece on the board lateral wall and being located the wire winding arc piece one side around the ring, the lateral wall of board and the top that is located whole round of mechanism are equipped with disconnected silk mechanism, still including setting up the plastic mechanism that just is located whole round of mechanism one side on the board, plastic mechanism is including the supporting disk that is used for correcting the subassembly that flattens of welding ring and is located the subassembly below that flattens, be equipped with the installation component that is used for fixed supporting disk on the board, be equipped with the guide subassembly that is used for with the leading-in supporting disk of welding ring on the board.

By adopting the technical scheme, firstly, the material supporting disc is fixed on the supporting table by the aid of the mounting assembly, so that the material supporting disc is opposite to the flattening assembly, then the welding wire is fed into the rounding mechanism by the wire feeding mechanism, the rounding of the welding wire is realized by the arrangement of the wire winding arc block and the rounding ring, the welding wire is cut off by the wire breaking mechanism after the welding wire is rounded and formed, the welding ring is finally formed, at the moment, the welding ring is guided into the material supporting disc by the aid of the material guiding assembly, and finally, the flattened welding ring can be corrected and flattened by the flattening assembly; adopt the orthotic devices that above-mentioned structure constitutes, can replace artifical manual collection to weld the ring and correct and weld the ring, labour saving and time saving has improved machining efficiency.

Optionally, the upper surface of the tray is provided with a guide chute, the bottom wall of the guide chute is provided with a limiting groove for accommodating the welding ring, and the cross-sectional area of the guide chute gradually increases from one side close to the limiting groove to one side far away from the limiting groove.

Through adopting above-mentioned technical scheme, get into the welding ring in the baffle box, along with the guide effect of baffle box, directly slide in the spacing inslot, the setting of spacing groove plays the effect of collecting to the welding ring.

Optionally, the subassembly that flattens is including installing the support on the board lateral wall, sliding the elevator of connection on the support lateral wall and the post that flattens of threaded connection in the elevator bottom, the lateral wall of support just is equipped with the lift groove that supplies the elevator to slide along the direction of height, be equipped with the driving piece that the drive elevator goes up and down in the lift inslot.

By adopting the technical scheme, the lifting block is driven to lift by the driving piece, the flattening column is driven to lift synchronously, and when the flattening column is inserted into the limiting groove, the flattening column can correct and flatten the butt ring; the flattening mode is simple in structure and convenient to operate.

Optionally, the driving part comprises a motor installed on the wall of the lifting groove, an adjusting disc connected with a driving shaft of the motor, and a linkage rod rotatably connected with the eccentric position of the side wall of the adjusting disc, and one end of the linkage rod, far away from the adjusting disc, is rotatably connected with the top wall of the lifting block.

Through adopting above-mentioned technical scheme, starter motor drives the adjustment disk and rotates, because the one end of gangbar rotates with the lateral wall off-centre department of adjustment disk to be connected, and the other end of gangbar rotates with the roof of elevator and is connected, and the lift groove plays direction and limiting displacement to the sliding of elevator, and then drives the elevator and goes up and down at the lift inslot to the post that will flatten inserts the spacing inslot, with the flattening of realization butt welding ring.

Optionally, lateral wall one side of board is equipped with a supporting bench, the installation component includes the vertical piece of two relative settings, the horizontal piece that links to each other with vertical piece top, a supporting bench's upper surface just is equipped with two relative spouts, vertical piece slides in the spout, be equipped with the cavity that is linked together with the spout in the supporting bench, the bottom of vertical piece is passed the spout and is stretched into in the cavity, be equipped with the regulating part that is used for adjusting interval between two vertical pieces in the cavity, the lower surface of tray is equipped with the mounting disc, the lower surface of mounting disc is equipped with water flat piece and vertical piece male mounting groove, one side cell wall of mounting groove is equipped with water flat piece male horizontal groove.

Through adopting above-mentioned technical scheme, at first in the top and the horizontal piece of vertical piece all inserted the mounting groove, the lower surface of mounting disc and the upper surface butt of brace table simultaneously, the horizontal groove sets up on the cell wall that holds in the palm the charging tray is kept away from to the mounting groove, utilizes two vertical pieces of regulating part drive to keep away from each other this moment, and then can insert the horizontal piece in the horizontal groove, and then can fix the mounting disc on brace table, realized fixed to the installation of holding in the palm the charging tray.

Optionally, the adjusting part includes a bidirectional cylinder located between the two vertical blocks, a cylinder body of the bidirectional cylinder is installed on an inner bottom wall of the cavity, a piston rod of the bidirectional cylinder is connected with the vertical blocks, and a telescopic direction of the piston rod of the bidirectional cylinder is the same as a length direction of the sliding groove.

Through adopting above-mentioned technical scheme, start two-way cylinder, two-way cylinder's piston rod stretches out, and the vertical piece of drive slips in the cavity, and the interval between two vertical pieces at this moment crescent, and then along with slipping of vertical piece, can insert the horizontal groove with the horizontal piece to can fix the mounting disc on a supporting bench.

Optionally, the inner bottom wall of the cavity is provided with a guide groove, and the bottom wall of the vertical block is provided with a guide block sliding in the guide groove.

Through adopting above-mentioned technical scheme, the cooperation of guide way and guide block plays further spacing and guide effect to sliding of vertical piece, has improved the stability of vertical piece process of sliding.

Optionally, the guide assembly comprises a first diagonal rod positioned on one side of the wire winding arc block, a second diagonal rod connected with the lower end of the first diagonal rod, and a third diagonal rod connected with the lower end of the second diagonal rod, the first diagonal rod is used for penetrating through the welding ring, the higher end of the first diagonal rod is connected with the side wall of the machine table, and the lower end of the third diagonal rod extends into the guide chute.

By adopting the technical scheme, the first inclined rod is positioned at one side of the wire winding arc block, so that when a wire feeding mechanism feeds wires, the welding wires are firstly fed below the first inclined rod, then the welding wires are fed below the wire winding arc block, and then the finally wound and formed welding rings can be sleeved on the first inclined rod along with the guiding of a winding ring, and further the welding rings can be guided into the guide chute through the guiding of the first inclined rod, the second inclined rod and the third inclined rod; this guide mechanism can replace artifical hand to collect and weld the ring, and labour saving and time saving has improved machining efficiency.

In summary, the present application includes at least one of the following beneficial technical effects:

1. the welding rings are guided into the material supporting disc by the material guiding assembly, and the flattened welding rings can be corrected and flattened by the flattening assembly, so that manual collection of the welding rings and correction of the welding rings can be replaced, time and labor are saved, and the machining efficiency is improved;

2. the mounting mode is simple in structure, facilitates dismounting of the material supporting disc, facilitates replacement of material supporting discs with different sizes and specifications by personnel, enables the limiting groove to accommodate welding rings with different sizes and specifications in an adaptive mode, and is wide in application range;

3. the welding wire is firstly fed into the lower portion of the first inclined rod, then the welding wire is fed into the lower portion of the wire winding arc block, then the welding ring after final winding forming can be sleeved on the first inclined rod along with the guiding of the winding ring, and at the moment, the welding ring can be finally collected in the guide chute instead of manual hands through the guiding of the first inclined rod, the second inclined rod and the third inclined rod, so that the time and the labor are saved, and the processing efficiency is improved.

Drawings

Fig. 1 is a schematic overall structure diagram of a high-precision correction device for processing a weld ring according to an embodiment of the present application.

Fig. 2 is a sectional view taken along line a-a of fig. 1.

Fig. 3 is an enlarged view of a portion a in fig. 2.

FIG. 4 is a schematic diagram showing a flattening assembly.

Description of reference numerals: 1. a machine platform; 2. a wire feeder; 3. a rounding mechanism; 31. a wire winding arc block; 32. encircling the circular ring; 4. a wire breaking mechanism; 5. a shaping mechanism; 6. a flattening assembly; 61. a support; 62. a lifting block; 63. flattening the column; 64. a lifting groove; 65. a drive member; 651. a motor; 652. an adjusting disk; 653. a linkage rod; 7. a material supporting disc; 71. a material guide chute; 72. a limiting groove; 8. mounting the component; 81. a support table; 82. a vertical block; 83. a horizontal block; 84. a chute; 85. a cavity; 86. a bidirectional cylinder; 87. mounting a disc; 88. mounting grooves; 89. a horizontal groove; 9. a material guiding assembly; 91. a first diagonal member; 92. a second diagonal member; 93. a third diagonal member; 10. a guide groove; 11. and a guide block.

Detailed Description

The present application is described in further detail below with reference to figures 1-4.

The embodiment of the application discloses weld ring processing and use high accuracy correcting device. Referring to fig. 1, the straightening device includes a machine table 1 arranged in a rectangular shape, a wire feeding mechanism 2 and a rounding mechanism 3 are sequentially arranged on a side wall of the machine table 1, a wire breaking mechanism 4 is arranged on the side wall of the machine table 1 and above the rounding mechanism 3, the rounding mechanism 3 includes a wire winding arc block 31 and two wire winding rings 32 arranged on the side wall of the machine table 1, and the two wire winding rings 32 are arranged on one side of the wire winding arc block 31 and are arranged vertically and oppositely.

Referring to fig. 1 and 2, a shaping mechanism 5 is disposed on a side wall of the machine table 1 and on a side of the rounding mechanism 3 away from the rounding mechanism 3, and the shaping mechanism 5 includes a material tray 7 located on one side of the machine table 1 and a flattening assembly 6 mounted on the side wall of the machine table 1.

Referring to fig. 2 and 3, the material supporting disc 7 is located below the flattening assembly 6, the machine table 1 is provided with an installation assembly 8 for fixing the material supporting disc 7, the upper surface of the material supporting disc 7 is provided with a material guide groove 71, the bottom wall of the material guide groove 71 opposite to the notch thereof is provided with a limiting groove 72 for accommodating welding rings, the wall of the material guide groove 71 is provided with an inclined surface, the lower end of the material guide groove 71 faces the notch of the limiting groove 72, the side wall of the machine table 1 is provided with a material guide assembly 9 for guiding welding rings into the welding rings, the wound welding rings can be guided into the limiting groove 72 by the arrangement of the material guide assembly 9 and the material guide groove 71, the collection of the welding rings is realized, and then the flattening mechanism is used for flattening and correcting the welding rings collected in the limiting groove 72; adopt the orthotic devices that above-mentioned structure constitutes, replace artifical manual collection to weld the ring and flatten, labour saving and time saving has improved machining efficiency.

Referring to fig. 2 and 3, the material guiding assembly 9 includes a first diagonal rod 91 located on one side of the wire winding arc block 31, the first diagonal rod 91 is used for penetrating through the inside of the welding ring, a higher end of the first diagonal rod 91 is connected with the side wall of the machine table 1, the other end of the first diagonal rod 91 faces the ground and is connected with a second diagonal rod 92, a lower end of the second diagonal rod 92 faces the ground and is connected with a third diagonal rod 93, and a lower end of the third diagonal rod 93 extends into the material guiding groove 71.

During actual processing, the wire feeding mechanism 2 sends the welding wire from the lower part of the first inclined rod 91 to the lower part of the wire-winding arc block 31, then the welding wire is fed continuously and the wire-winding circle performs the whole circle on the welding wire, and finally the welding ring formed by winding drops onto the first inclined rod 91; this guide mode can be with the welding ring direct introduction spacing groove 72 that the coiling is good in, and then can replace artifical manual collection welding ring, and save time, laborsaving has improved machining efficiency.

Referring to fig. 2 and 3, a supporting table 81 for supporting the tray 7 is arranged on the side wall of the machine table 1, the mounting assembly 8 includes two vertical blocks 82 which are arranged oppositely, the top ends of the two vertical blocks 82 are connected with a horizontal block 83, two opposite sliding grooves 84 are arranged on the upper surface of the supporting table 81, the length direction of the sliding grooves 84 is in the same direction as the axial direction of the supporting table 81, the two sliding grooves 84 are in one-to-one correspondence with the two vertical blocks 82, the sliding grooves 84 of the vertical blocks 82 slide in, a mounting disc 87 is arranged on the lower surface of the tray 7, a mounting groove 88 is arranged on the lower surface of the mounting disc 87, the length dimension of the mounting groove 88 is the sum of the length dimension of the horizontal block 83 and the length dimension of the vertical blocks 82, and further, when it is installed, the installation groove 88 is aligned with the horizontal block 83 and the vertical block 82, the installation plate 87 is moved down, so that the lower surface of the mounting plate 87 is fitted to the upper surface of the support table 81, and at this time, the horizontal block 83 and the vertical block 82 are inserted into the mounting grooves 88.

In order to fix the mounting disc 87 on the supporting table 81, a horizontal groove 89 is formed in one side groove wall of the mounting groove 88 adjacent to the notch of the mounting groove 88, the horizontal groove 89 is formed in the groove wall of the mounting groove 88 far away from the tray 7, the horizontal groove 89 is used for inserting the horizontal block 83, a cavity 85 communicated with the two sliding grooves 84 is formed in the supporting table 81, one end, far away from the horizontal block 83, of the vertical block 82 extends into the cavity 85, an adjusting piece for adjusting the distance between the two vertical blocks 82 is arranged in the cavity 85, when the two vertical blocks 82 are driven to be far away from each other by the adjusting piece, the vertical block 82 is driven to slide in the sliding grooves 84, the horizontal block 83 can be inserted into the horizontal groove 89, and the mounting disc 87 can be fixed on the upper surface of the supporting table 81; this mounting means, simple structure makes things convenient for dismouting support charging tray 7, and the welding ring when the spacing inslot 72 piles up full back, can take off support charging tray 7 to taking out the good welding ring of collection and correction.

Referring to fig. 3, the adjusting part includes the two-way cylinder 86 of the horizontal setting diapire in cavity 85, two-way lead screw is located between two vertical blocks 82, two piston rods of two-way cylinder 86 respectively with two vertical blocks 82 one-to-one, the piston rod of two-way cylinder 86 links to each other with the lateral wall of vertical block 82, the flexible direction of the piston rod of two-way cylinder 86 is syntropy with the length direction of spout 84, start two-way cylinder 86, the piston rod of two-way cylinder 86 is flexible, and then drive vertical block 82 and slide, thereby can insert horizontal block 83 in horizontal groove 89, so that fix mounting disc 87 on supporting bench 81.

Referring to fig. 3, the inner bottom wall of the cavity 85 is provided with a guide groove 10, the length direction of the guide groove 10 is the same as that of the sliding groove 84, the bottom wall of the vertical block 82 is provided with a guide block 11 sliding in the guide groove 10, the guide block 11 and the guide groove 10 are matched to guide and limit the sliding of the vertical block 82, and the stability of the sliding process of the vertical block 82 is improved.

Referring to fig. 3 and 4, a support 61 is installed on the side wall of the machine table 1 and above the material supporting disc 7, a lifting groove 64 penetrating through the upper surface and the lower surface of the support 61 is formed in the side wall of the support 61, the flattening assembly 6 comprises a lifting block 62 connected in the lifting groove 64 in a sliding manner, a flattening column 63 is connected to the bottom wall of the lifting block 62 in a threaded manner, the flattening column 63 is opposite to a limiting groove 72 up and down, a driving piece 65 for driving the lifting block 62 to lift is arranged in the lifting groove 64, the flattening column 63 can be inserted into the limiting groove 72 by driving the lifting block 62 to lift, and therefore the correction and flattening of the butt welding ring are achieved; and the flattening column 63 is in threaded connection with the bottom of the lifting block 62, so that the flattening column 63 with a proper size specification is conveniently selected according to the diameter size of the welding ring, and the welding rings with different diameters and sizes are flattened.

Referring to fig. 4, the driving member 65 includes a motor 651 installed at the top of the groove wall of the lifting groove 64, a supporting groove for placing the motor 651 is provided on the groove wall of the lifting groove 64, a regulating disc 652 is connected to a driving shaft of the motor 651, a linkage rod 653 is rotatably connected to an eccentric position of the side wall of the regulating disc 652, one end of the linkage rod 653, which is far away from the regulating disc 652, is rotatably connected to the top wall of the lifting block 62, the motor 651 is started to drive the regulating disc 652 to rotate and drive the linkage rod 653 to swing, because one end of the linkage rod 653 is rotatably connected to the side wall of the lifting block 62, and the lifting groove 64 plays a guiding and limiting role in sliding the lifting block 62, and further drives the lifting block 62 to lift in the lifting groove 64 along with the swinging of the linkage rod 653, and drives the flattening column 63 to synchronously lift, so as to flatten and correct the butt welding ring.

The implementation principle of the high-precision correction device for welding ring machining in the embodiment of the application is as follows: at first all insert mounting groove 88 with horizontal piece 83 and vertical piece 82 in, restart two-way cylinder 86, the piston rod of two-way lead screw stretches out, drives two vertical pieces 82 and keeps away from each other, can insert horizontal piece 83 horizontal groove 89 simultaneously in, and then can fix mounting disc 87 on a supporting bench 81, realized the fixed of holding in the palm charging tray 7.

Then the welding wire is sequentially fed below the first inclined rod 91 and below the wire winding arc block 31 through the wire feeding mechanism 2, the welding wire can be wound into a circle along with the guiding of the two winding rings 32, after the welding wire is wound into the circle, the welding wire is cut off by the wire cutting mechanism 4 to form a welding ring, finally the welding ring is sleeved on the first inclined rod 91, the welding ring can be guided into the guide groove 71 along with the guiding of the first inclined rod 91, the second inclined rod 92 and the third inclined rod 93, and the welding ring can be guided into the limiting groove 72 through the guiding of the guide groove 71, so that the collection of the welding ring is realized.

Finally, the motor 651 is started again, the adjusting disc 652 is driven to rotate, the linkage rod 653 is driven to swing, the lifting groove 64 plays a role in guiding and limiting the sliding of the lifting block 62, the lifting block 62 is driven to lift along with the swinging of the linkage rod 653, and the leveling post 63 is driven to lift so as to correct and level the weld ring.

The above embodiments are preferred embodiments of the present application, and the protection scope of the present application is not limited by the above embodiments, so: all equivalent changes made according to the structure, shape and principle of the present application shall be covered by the protection scope of the present application.

Claims

1. The utility model provides a weld ring processing and use high accuracy correcting device, includes board (1), sets gradually wire drive feed mechanism (2), whole round mechanism (3) on board (1) lateral wall, whole round mechanism (3) are including installing wire winding arc piece (31) on board (1) lateral wall and be located wire winding arc piece (31) one side around ring (32), the lateral wall of board (1) and the top that is located whole round mechanism (3) are equipped with disconnected silk mechanism (4), its characterized in that: still including setting up plastic mechanism (5) on board (1) and being located whole circle mechanism (3) one side, plastic mechanism (5) are including being used for correcting flattening subassembly (6) of welding the ring and being located support charging tray (7) of flattening subassembly (6) below, be equipped with installation component (8) that are used for fixed support charging tray (7) on board (1), be equipped with guide subassembly (9) that are used for will welding the ring and lead in support charging tray (7) on board (1).

2. The high-precision correction device for weld ring machining according to claim 1, characterized in that: the upper surface of the tray (7) is provided with a guide chute (71), the bottom wall of the guide chute (71) is provided with a limiting groove (72) for accommodating a welding ring, and the cross sectional area of the guide chute (71) is gradually increased from one side close to the limiting groove (72) to one side far away from the limiting groove (72).

3. The high-precision correction device for weld ring machining according to claim 2, characterized in that: flattening subassembly (6) including installing support (61) on board (1) lateral wall, sliding connection elevator (62) and the flattening post (63) of threaded connection in elevator (62) bottom on support (61) lateral wall, flattening post (63) just to spacing groove (72), the lateral wall of support (61) and along the direction of height be equipped with lift groove (64) that supplies elevator (62) to slide, be equipped with driving piece (65) that drive elevator (62) go up and down in lift groove (64).

4. The high-precision correction device for weld ring machining according to claim 3, characterized in that: the driving piece (65) comprises a motor (651) arranged on the wall of the lifting groove (64), an adjusting disc (652) connected with the driving shaft of the motor (651), and a linkage rod (653) rotatably connected with the eccentric position of the side wall of the adjusting disc (652), wherein one end, far away from the adjusting disc (652), of the linkage rod (653) is rotatably connected with the top wall of the lifting block (62).

5. The high-precision correction device for weld ring machining according to claim 4, characterized in that: a supporting table (81) is arranged on one side of the side wall of the machine table (1), the mounting assembly (8) comprises two vertical blocks (82) which are arranged oppositely and a horizontal block (83) connected with the top ends of the vertical blocks (82), the upper surface of the supporting platform (81) is provided with two opposite sliding grooves (84), the vertical block (82) slides in the sliding grooves (84), a cavity (85) communicated with the sliding chute (84) is arranged in the supporting platform (81), the bottom end of the vertical block (82) passes through the sliding groove (84) and extends into the cavity (85), an adjusting piece for adjusting the distance between the two vertical blocks (82) is arranged in the cavity (85), the lower surface of the tray (7) is provided with a mounting disc (87), the lower surface of the mounting disc (87) is provided with a mounting groove (88) for inserting a horizontal block (83) and a vertical block (82), and a horizontal groove (89) for inserting the horizontal block (83) is formed in the groove wall on one side of the mounting groove (88).

6. The high-precision correction device for weld ring machining according to claim 5, characterized in that: the adjusting piece comprises a bidirectional air cylinder (86) located between two vertical blocks (82), the cylinder body of the bidirectional air cylinder (86) is installed on the inner bottom wall of the cavity (85), the piston rod of the bidirectional air cylinder (86) is connected with the vertical blocks (82), and the telescopic direction of the piston rod of the bidirectional air cylinder (86) is the same as the length direction of the sliding groove (84).

7. The high-precision correction device for weld ring machining according to claim 6, characterized in that: the inner bottom wall of the cavity (85) is provided with a guide groove (10), and the bottom wall of the vertical block (82) is provided with a guide block (11) which slides in the guide groove (10).

8. The high-precision correction device for weld ring machining according to claim 2, characterized in that: guide subassembly (9) are including first down tube (91) that is located wire winding arc piece (31) one side, second down tube (92) that link to each other with the lower one end of first down tube (91) and third down tube (93) that link to each other with the lower one end of second down tube (92), first down tube (91) are used for wearing to establish in the welding ring, the higher one end of first down tube (91) links to each other with the lateral wall of board (1), the lower one end of third down tube (93) extends to in baffle box (71).