CN215282410U

CN215282410U - Timber bending device

Info

Publication number: CN215282410U
Application number: CN202121629838.9U
Authority: CN
Inventors: 哈赵毅; 李小雪; 李秀; 虢勇
Original assignee: Huizhou Shenghui Household Products Co ltd
Current assignee: Huizhou Shenghui Household Products Co ltd
Priority date: 2021-07-16
Filing date: 2021-07-16
Publication date: 2021-12-24
Anticipated expiration: 2031-07-16

Abstract

The utility model discloses a timber bending device belongs to timber technical field of bending, including workstation, conveyor, fixing device and bending device, the workstation sets up on the horizontal plane, conveyor sets up on the workstation, fixing device sets up on conveyor's delivery end, bending device sets up on the workstation and bending device's bending end is located conveyor directly over, and fixing device fixes the ligneous both ends that will bend, and conveyor carries the timber of fixing to bending device's bottom, and bending device bends the angle of the position and the requirement that the timber is different as required.

Description

Timber bending device

Technical Field

The utility model relates to a timber technical field that bends especially relates to a timber bending device.

Background

In the decoration or furniture processing of the present city, bent wood or board is generally used.

Current publication number CN211941311U discloses a timber bending device for furniture production relates to furniture processing technology field. Including the device case, fixed plate and fixture, the fixed plate is fixed with the device case lateral wall, fixed plate upper end central authorities are provided with the supporting shoe, crooked timber is placed in the supporting shoe top, fixture is including rotating the lead screw, slider and U type splint, it passes the device roof portion and is connected with outside rotation motor output shaft to rotate the lead screw, it runs through the slider and rotates with the slider to rotate the lead screw to be connected, slider one end and device case lateral wall sliding connection, other end fixed connection U type splint, crooked timber both ends are placed respectively in the opening of the U type splint of both sides. The utility model overcomes prior art's is not enough, reasonable in design, and convenient to use can effectively carry out the buckling of different angles to timber, need not to prepare the mould, promotes ligneous efficiency of buckling, reduces manufacturing cost. However, in the process of bending the wood by the device, the position of the bending device needs to be readjusted when the bending position of the wood is different, so that the time and the labor are consumed, the control strength is poor, and the wood is easy to damage.

SUMMERY OF THE UTILITY MODEL

The embodiment of the utility model provides a timber bending device to solve the angle that can not control to bend, need readjust bending device's position simultaneously to the position that timber was bent moreover, so not only consuming time and wasting power, the dynamics of controlling does not good still damage ligneous technical problem easily moreover.

The embodiment of the utility model provides an adopt following technical scheme: the wood bending device comprises a workbench, a conveying device, a fixing device and a bending device, wherein the workbench is arranged on a horizontal plane, the conveying device is arranged on the workbench, the fixing device is arranged at the conveying end of the conveying device, the bending device is arranged on the workbench, and the bending end of the bending device is positioned right above the conveying device.

Further, conveyor includes conveyor motor, first belt pulley, second belt pulley, third belt, places piece, two first slide bars and four first mount pads, and two bisymmetry settings of four first mount pads are on the workstation, two first slide bar symmetry sets up on four first mount pads and with four first mount pad normal running fit, place the piece setting on two first slide bars, conveyor motor sets up on the workstation, first belt pulley sets up on conveyor motor's main shaft and connects on a first slide bar, the second belt pulley sets up on another first slide bar, the third belt cover is established on first belt pulley and second belt pulley.

Furthermore, the fixing devices are provided with two groups, the two groups of fixing devices are symmetrically arranged on the placing block of the conveying device, each fixing device comprises a first air cylinder, a base, a connecting block, a first connecting rod, a second connecting rod, a third connecting rod, a fourth connecting rod, a third rotating shaft, a fourth rotating shaft and a clamping arm, the first air cylinder is arranged on the placing block, the base is fixedly arranged on the first air cylinder, the connecting block is connected with the output end of the first air cylinder, the first connecting rod, the second connecting rod, the third connecting rod, the fourth connecting rod, the first rotating shaft, the third rotating shaft and the clamping arm are respectively provided with two groups, one end of each first connecting rod is respectively connected with the connecting block, the other end of each first connecting rod is respectively hinged with one second connecting rod, and the other end of each second connecting rod is respectively connected with one third rotating shaft, the two third rotating shafts are respectively arranged on one side of the base, the two fourth rotating shafts are arranged beside the third rotating shafts, one ends of the two third connecting rods are respectively connected with one third rotating shaft, the other ends of the two third connecting rods are respectively connected with one clamping arm, one ends of the two fourth connecting rods are respectively connected with one third rotating shaft, and the other ends of the two fourth connecting rods are respectively connected with one clamping arm.

Furthermore, the bending device comprises a moving assembly and a bending assembly, the moving assembly is arranged on the workbench and located right above the conveying device, and the bending assembly is arranged at the moving end of the moving assembly.

Further, the movable assembly comprises a fixed frame, an installation block, a movable motor, a third gear, a toothed plate and two supporting blocks, the fixed frame is arranged on the workbench, the fixed frame is provided with two sliding grooves for the supporting blocks to slide, the installation block is arranged at the top of the fixed frame, the movable motor is arranged on the installation block, the third gear is arranged on a main shaft of the movable motor, the toothed plate is arranged at the top of the fixed frame and in sliding fit with the top of the fixed frame, the third gear is meshed with the toothed plate, and the supporting blocks are fixedly arranged below the toothed plate and in sliding fit with the two sliding grooves respectively.

Further, the bending component comprises a bending block, an installation frame, a bending motor, a sliding rod, a bidirectional threaded rod, an installation plate, two sliding sleeves, four rotating plates and four rotating seats, the installation frame is arranged below the two supporting blocks, the bending motor is arranged on the side wall of the installation frame, a main shaft of the bending motor is in rotating fit with the side wall of the installation frame, one end of the bidirectional threaded rod is in transmission connection with the main shaft of the bending motor, the other end of the bidirectional threaded rod is in rotating connection with the installation frame, the sliding rod is horizontally arranged on the installation frame, the two sliding sleeves are in threaded connection with the bidirectional threaded rod and in sliding fit with the sliding rod, one ends of the four rotating plates are in pairwise symmetry and are in rotating connection with the two sliding sleeves, the four rotating seats are in pairwise symmetry and fixedly connected with the top of the installation plate, and the other end of each rotating plate is in rotating connection with the rotating seat, the bending block is arranged at the bottom of the mounting plate.

The embodiment of the utility model provides an above-mentioned at least one technical scheme who adopts can reach following beneficial effect:

firstly, two ends of wood to be bent are fixed by a fixing device, the fixed wood is conveyed to the bottom of a bending device by a conveying device, and the bending device bends different positions and required angles of the wood according to requirements.

Two, put into two fixing device with ligneous both ends on, it reciprocates to drive the connecting block through first cylinder, the connecting block drives the head rod motion, the head rod is articulated with the second connecting rod, the second connecting rod is connected with the third axis of rotation, the third axis of rotation drives the third connecting rod and moves, fourth axis of rotation and fourth connecting rod cooperation third axis of rotation and third connecting rod drive the centre gripping arm and carry out the closed operation of switch, thereby fix ligneous both ends, setting through the fixed bolster device can be fixed timber, make things convenient for bending device to bend the operation to timber.

Thirdly, when the position of the bending component needs to be adjusted, the work of the moving motor drives the third gear arranged on the main shaft of the moving motor to rotate, the work of the third gear drives the toothed plate which is meshed with the third gear to slide at the top of the fixed frame, the toothed plate slides at the top of the fixed frame to drive two supporting blocks fixed at the bottom of the toothed plate to slide in two sliding grooves at the top of the fixed frame, the two supporting blocks slide to drive the bending component fixed under the supporting blocks to move, the bending work under different positions of wood can be realized through the arrangement of the moving component, the flexibility of the device is improved, and the practicability of the device is also improved.

Fourthly, when conveyor carries the fixed timber and bends under the piece, the motor work of bending drives the two-way threaded rod and rotates on the installation frame, the two-way threaded rod rotates on the installation frame and drives two sliding sleeves and be relative motion on the slide bar, two sliding sleeves are relative motion and drive four rotor plates and rotate on four rotation seats, thereby drive the mounting panel downstream, the mounting panel downstream drives the piece of bending downstream that sets up in the mounting panel bottom and bends timber, through the setting of the subassembly of bending, can control the angle that timber was bent, the practicality and the convenience of this device have been improved.

Drawings

The accompanying drawings, which are described herein, serve to provide a further understanding of the invention and constitute a part of this specification, and the exemplary embodiments and descriptions thereof are provided for explaining the invention without unduly limiting it. In the drawings:

fig. 1 is a schematic perspective view of the present invention;

fig. 2 is a schematic perspective view of the conveying device of the present invention;

fig. 3 is a schematic perspective view of the fixing device of the present invention;

fig. 4 is a schematic perspective view of the moving assembly of the present invention;

fig. 5 is a schematic view of the three-dimensional structure of the bending assembly of the present invention.

Reference numerals

The bending machine comprises a workbench 1, a conveying device 2, a conveying motor 21, a first belt pulley 22, a second belt pulley 23, a third belt 24, a placing block 25, a first sliding rod 26, a first mounting seat 27, a fixing device 3, a first cylinder 31, a base 32, a connecting block 33, a first connecting rod 34, a second connecting rod 35, a third connecting rod 36, a fourth connecting rod 37, a third rotating shaft 38, a fourth rotating shaft 39, a clamping arm 30, a bending device 4, a moving component 41, a fixing frame 411, a mounting block 412, a moving motor 413, a third gear 414, a toothed plate 415, a supporting block 416, a bending component 42, a bending block 421, a mounting frame 422, a bending motor 423, a second sliding rod 424, a bidirectional threaded rod 425, a mounting plate 426, a sliding sleeve 427, a rotating plate 428 and a rotating seat 429.

Detailed Description

To make the purpose, technical solution and advantages of the present invention clearer, the following will combine the embodiments of the present invention and the corresponding drawings to clearly and completely describe the technical solution of the present invention. It is to be understood that the embodiments described are only some embodiments of the invention, and not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

The technical solutions provided by the embodiments of the present invention are described in detail below with reference to the accompanying drawings.

Referring to fig. 1 to 5, an embodiment of the present invention provides a wood bending device, including a workbench 1, a conveying device 2, a fixing device 3 and a bending device 4, wherein the workbench 1 is arranged on a horizontal plane, the conveying device 2 is arranged on the workbench 1, the fixing device 3 is arranged on a conveying end of the conveying device 2, the bending device 4 is arranged on the workbench 1, and a bending end of the bending device 4 is located right above the conveying device 2; fixing device 3 fixes the both ends of timber that need bend, and conveyor 2 carries the bottom to bending device 4 with fixed timber, and bending device 4 bends different positions of timber and required angle as required.

Preferably, referring to fig. 2, the conveying device 2 of the present invention includes a conveying motor 21, a first belt pulley 22, a second belt pulley 23, a third belt pulley 24, a placing block 25, two first sliding rods 26 and four first mounting seats 27, wherein the four first mounting seats 27 are symmetrically arranged on the workbench 1 in pairs, two first sliding rods 26 are symmetrically arranged on the four first mounting seats 27 and are rotationally matched with the four first mounting seats 27, the placing block 25 is arranged on the two first sliding rods 26, the conveying motor 21 is arranged on the workbench 1, the first belt pulley 22 is arranged on a main shaft of the conveying motor 21 and is connected to one first sliding rod 26, the second belt pulley 23 is arranged on the other first sliding rod 26, and the third belt pulley 24 is sleeved on the first belt pulley 22 and the second belt pulley 23; after fixing device 3 fixes timber, conveying motor 21 work drives first belt pulley 22 work, and first belt pulley 22 drives third belt 24 and rotates, and third belt 24 drives second belt pulley 23 and rotates to the piece 25 is placed in the drive and is removed on two first slide bars 26, and it drives fixed timber and removes to place the piece 25.

Preferably, referring to fig. 3, the fixing device 3 of the present invention is provided with two sets, two sets of the fixing devices 3 are symmetrically disposed on the placing block 25 of the conveying device 2, each of the fixing devices 3 includes a first cylinder 31, a base 32, a connecting block 33, a first connecting rod 34, a second connecting rod 35, a third connecting rod 36, a fourth connecting rod 37, a third rotating shaft 38, a fourth rotating shaft 39 and a clamping arm 30, the first cylinder 31 is disposed on the placing block 25, the base 32 is fixedly disposed on the first cylinder 31, the connecting block 33 is connected to an output end of the first cylinder 31, the first connecting rod 34, the second connecting rod 35, the third connecting rod 36, the fourth connecting rod 37, the first rotating shaft, the third rotating shaft 38 and the clamping arm 30 are provided with two sets, one end of the two first connecting rods 34 is respectively connected to the connecting block 33, the other end of the two first connecting rods 34 is respectively hinged to one second connecting rod 35, the other ends of the two second connecting rods 35 are respectively connected with a third rotating shaft 38, the two third rotating shafts 38 are respectively arranged on one side of the base 32, the two fourth rotating shafts 39 are arranged on the side of the third rotating shafts 38, one ends of the two third connecting rods 36 are respectively connected with the third rotating shafts 38, the other ends of the two third connecting rods 36 are respectively connected with a clamping arm 30, one ends of the two fourth connecting rods 37 are respectively connected with the third rotating shafts 38, and the other ends of the two fourth connecting rods 37 are respectively connected with the clamping arm 30; put into two fixing device 3 with ligneous both ends on, it reciprocates to drive connecting block 33 through first cylinder 31, connecting block 33 drives the motion of head rod 34, head rod 34 is articulated with second connecting rod 35, second connecting rod 35 is connected with third axis of rotation 38, third axis of rotation 38 drives third connecting rod 36 and moves, fourth axis of rotation 39 and fourth connecting rod 37 cooperate third axis of rotation 38 and third connecting rod 36 to drive centre gripping arm 30 and carry out the closed operation of switch, thereby fix ligneous both ends, can fix timber through the setting of fixed bolster device, make things convenient for bending device 4 to bend the operation to timber.

Preferably, referring to fig. 1, the bending device 4 of the present invention includes a moving assembly 41 and a bending assembly 42, the moving assembly 41 is disposed on the workbench 1 and located right above the conveying device 2, and the bending assembly 42 is disposed on a moving end of the moving assembly 41; the moving assembly 41 moves the bending assembly 42 left and right, so that bending work can be conveniently performed on different positions of wood, and the bending assembly 42 can bend at a required angle.

Preferably, referring to fig. 4, the moving assembly 41 of the present invention includes a fixed frame 411, a mounting block 412, a moving motor 413, a third gear 414, a toothed plate 415 and two supporting blocks 416, wherein the fixed frame 411 is disposed on the working platform 1, two sliding grooves for the supporting blocks 416 to slide are disposed on the fixed frame 411, the mounting block 412 is disposed at the top of the fixed frame 411, the moving motor 413 is disposed on the mounting block 412, the third gear 414 is disposed on the spindle of the moving motor 413, the toothed plate 415 is disposed at the top of the fixed frame 411 and is in sliding fit with the top of the fixed frame 411, the third gear 414 is engaged with the toothed plate 415, and the two supporting blocks 416 are fixedly disposed below the toothed plate 415 and are in sliding fit with the two sliding grooves, respectively; when the position of the bending component 42 needs to be adjusted, the work of the moving motor 413 drives the third gear 414 arranged on the main shaft of the moving motor 413 to rotate, the work of the third gear 414 drives the toothed plate 415 engaged with the third gear to slide at the top of the fixed frame 411, the toothed plate 415 drives the two supporting blocks 416 fixed at the bottom of the toothed plate 415 to slide in the two sliding grooves at the top of the fixed frame 411 in the sliding mode, the two supporting blocks 416 drive the bending component 42 fixed under the supporting blocks 416 to move in the sliding mode, the bending work of wood at different positions can be realized through the arrangement of the moving component 41, the flexibility of the device is improved, and the practicability of the device is also improved.

Preferably, referring to fig. 5, the bending assembly 42 of the present invention includes a bending block 421, a mounting frame 422, a bending motor 423, a second sliding rod 424, a bidirectional threaded rod 425, a mounting plate 426, two sliding sleeves 427, four rotating plates 428, and four rotating seats 429, wherein the mounting frame 422 is disposed below the two supporting blocks 416, the bending motor 423 is disposed on a sidewall of the mounting frame 422, a main shaft of the bending motor 423 is rotatably engaged with a sidewall of the mounting frame 422, one end of the bidirectional threaded rod 425 is drivingly connected to the main shaft of the bending motor 423, the other end of the bidirectional threaded rod 425 is rotatably connected to the mounting frame 422, the second sliding rod 424 is horizontally disposed on the mounting frame 422, two sliding sleeves 427 are each threadedly connected to the bidirectional threaded rod 425 and each slidably engaged with the second sliding rod 424, one ends of the four rotating plates 428 are rotatably connected to the two sliding sleeves 427 in a pairwise symmetrical manner, the four rotating seats 429 are fixedly connected to the top of the mounting plate 426 in a pairwise symmetrical manner, the other end of each rotating plate 428 is rotatably connected to the rotating seat 429, and the bending block 421 is arranged at the bottom of the mounting plate 426; when conveyor 2 carries fixed timber to bend piece 421 down, the work of bending motor 423 drives two-way threaded rod 425 and rotates on installation frame 422, two-way threaded rod 425 rotates on installation frame 422 and drives two sliding sleeves 427 and be relative motion on second sliding rod 424, two sliding sleeves 427 are relative motion and drive four rotor plates 428 and rotate on four rotation seats 429, thereby drive mounting panel 426 downstream, mounting panel 426 downstream drives the piece 421 downstream that bends that sets up in mounting panel 426 bottom and bends timber, through the setting of bending subassembly 42, can control the angle that timber was bent, the practicality and the convenience of this device have been improved.

The working principle is as follows: putting two ends of wood on two fixing devices 3, driving a connecting block 33 to move up and down through a first cylinder 31, driving a first connecting rod 34 to move by the connecting block 33, hinging the first connecting rod 34 with a second connecting rod 35, connecting the second connecting rod 35 with a third rotating shaft 38, driving a third connecting rod 36 to move by the third rotating shaft 38, matching a fourth rotating shaft 39 and a fourth connecting rod 37 with the third rotating shaft 38 and the third connecting rod 36 to drive a clamping arm 30 to carry out switch closing operation, thereby fixing the two ends of the wood, after the wood is fixed by the fixing devices 3, driving a first belt pulley 22 to work by a conveying motor 21, driving a third belt 24 to rotate by the first belt pulley 22, driving a placing block 25 to move on two first sliding rods 26, driving the fixed wood to move by the placing block 25, when the conveying device 2 conveys the fixed wood to the lower part of the bending block 421, the bending motor 423 works to drive the bidirectional threaded rod 425 to rotate on the mounting frame 422, the bidirectional threaded rod 425 rotates on the mounting frame 422 to drive the two sliding sleeves 427 to do relative motion on the second sliding rod 424, the two sliding sleeves 427 do relative motion to drive the four rotating plates 428 to rotate on the four rotating seats 429, so as to drive the mounting plate 426 to move downwards, the mounting plate 426 moves downwards to drive the bending block 421 arranged at the bottom of the mounting plate 426 to work downwards to bend the wood, when the position of the bending component 42 needs to be adjusted, the moving motor 413 works to drive the third gear 414 arranged on the main shaft of the moving motor 413 to rotate, the third gear 414 works to drive the toothed plate 415 engaged with the third gear to slide on the top of the fixed frame 411, the toothed plate 415 slides on the top of the fixed frame 411 to drive the two supporting blocks 416 fixed at the bottom of the toothed plate 415 to slide in the two sliding grooves at the top of the fixed frame 411, two supporting shoes 416 slide to drive and fix the subassembly 42 of bending under supporting shoe 416 and remove, can realize the work of bending under the different positions of timber through the setting of removal subassembly 41, have improved this device flexibility, have also improved the practicality of this device.

The above description is only an example of the present invention, and is not intended to limit the present invention. Various modifications and changes may occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims

1. The wood bending device is characterized by comprising a workbench (1), a conveying device (2), a fixing device (3) and a bending device (4), wherein the workbench (1) is arranged on a horizontal plane, the conveying device (2) is arranged on the workbench (1), the fixing device (3) is arranged at the conveying end of the conveying device (2), the bending device (4) is arranged on the workbench (1), and the bending end of the bending device (4) is positioned right above the conveying device (2).

2. The wood bending device according to claim 1, wherein the conveying device (2) comprises a conveying motor (21), a first belt pulley (22), a second belt pulley (23), a third belt (24), a placing block (25), two first sliding rods (26) and four first mounting seats (27), the four first mounting seats (27) are symmetrically arranged on the workbench (1) in pairs, the two first sliding rods (26) are symmetrically arranged on the four first mounting seats (27) and are rotationally matched with the four first mounting seats (27), the placing block (25) is arranged on the two first sliding rods (26), the conveying motor (21) is arranged on the workbench (1), the first belt pulley (22) is arranged on a main shaft of the conveying motor (21) and is connected to one first sliding rod (26), the second belt pulley (23) is arranged on the other first sliding rod (26), the third belt (24) is sleeved on the first belt pulley (22) and the second belt pulley (23).

3. The wood bending device according to claim 2, wherein the fixing devices (3) are arranged in two groups, the two groups of fixing devices (3) are symmetrically arranged on the placing block (25) of the conveying device (2), each fixing device (3) comprises a first air cylinder (31), a base (32), a connecting block (33), a first connecting rod (34), a second connecting rod (35), a third connecting rod (36), a fourth connecting rod (37), a third rotating shaft (38), a fourth rotating shaft (39) and a clamping arm (30), the first air cylinder (31) is arranged on the placing block (25), the base (32) is fixedly arranged on the first air cylinder (31), the connecting block (33) is connected with the output end of the first air cylinder (31), and the first connecting rod (34), the second connecting rod (35), the third connecting rod (36) and the clamping arm (30), The number of the fourth connecting rods (37), the number of the first rotating shafts, the number of the third rotating shafts (38) and the number of the clamping arms (30) are two, one end of each of the two first connecting rods (34) is connected with the connecting block (33), the other end of each of the two first connecting rods (34) is hinged to one second connecting rod (35), the other end of each of the two second connecting rods (35) is connected with one third rotating shaft (38), the two third rotating shafts (38) are arranged on one side of the base (32) respectively, the two fourth rotating shafts (39) are arranged beside the third rotating shafts (38), one end of each of the two third connecting rods (36) is connected with one third rotating shaft (38), the other end of each of the two third connecting rods (36) is connected with one clamping arm (30), one end of each of the two fourth connecting rods (37) is connected with one third rotating shaft (38) respectively, the other ends of the two fourth connecting rods (37) are respectively connected with a clamping arm (30).

4. The wood bending device according to claim 1, wherein the bending device (4) comprises a moving assembly (41) and a bending assembly (42), the moving assembly (41) is arranged on the workbench (1) and is positioned right above the conveying device (2), and the bending assembly (42) is arranged at the moving end of the moving assembly (41).

5. A wood bending apparatus according to claim 4, wherein: the moving component (41) comprises a fixed frame (411), a mounting block (412), a moving motor (413), a third gear (414), a toothed plate (415) and two supporting blocks (416), the fixed frame (411) is arranged on the workbench (1), two sliding grooves for the supporting block (416) to slide are arranged on the fixed frame (411), the mounting block (412) is disposed on the top of the fixed frame (411), the moving motor (413) is disposed on the mounting block (412), the third gear (414) is arranged on the main shaft of the moving motor (413), the toothed plate (415) is arranged at the top of the fixed frame (411) and is in sliding fit with the top of the fixed frame (411), the third gear (414) is meshed with the toothed plate (415), and the two supporting blocks (416) are fixedly arranged below the toothed plate (415) and are respectively in sliding fit with the two sliding grooves.

6. The wood bending device according to claim 5, wherein the bending assembly (42) comprises a bending block (421), a mounting frame (422), a bending motor (423), a second sliding rod (424), a bidirectional threaded rod (425), a mounting plate (426), two sliding sleeves (427), four rotating plates (428) and four rotating seats (429), the mounting frame (422) is arranged below the two supporting blocks (416), the bending motor (423) is arranged on the side wall of the mounting frame (422), the main shaft of the bending motor (423) is in rotating fit with the side wall of the mounting frame (422), one end of the bidirectional threaded rod (425) is in transmission connection with the main shaft of the bending motor (423), the other end of the bidirectional threaded rod (425) is in rotating connection with the mounting frame (422), the second sliding rod (424) is horizontally arranged on the mounting frame (422), the two sliding sleeves (427) are in threaded connection with a bidirectional threaded rod (425) and are in sliding fit with a second sliding rod (424), one ends of the four rotating plates (428) are in pairwise symmetrical and rotary connection with the two sliding sleeves (427), the four rotating seats (429) are in pairwise symmetrical and fixed connection with the top of the mounting plate (426), the other end of each rotating plate (428) is in rotary connection with the rotating seat (429), and the bending block (421) is arranged at the bottom of the mounting plate (426).