CN209882551U

CN209882551U - Power transmission assembly

Info

Publication number: CN209882551U
Application number: CN201920504963.3U
Authority: CN
Inventors: 胡济荣; 其他发明人请求不公开姓名
Original assignee: Zhejiang Xing Lai And Agricultural Equipment Co Ltd
Current assignee: Zhejiang Xing Lai And Agricultural Equipment Co Ltd
Priority date: 2019-04-15
Filing date: 2019-04-15
Publication date: 2020-01-03
Anticipated expiration: 2029-04-15

Abstract

The utility model relates to a power transmission assembly, support and slip table front support behind the slip table that includes power link mechanism, speed governing mechanism, long rocking arm and rocker, speed governing mechanism includes speed regulating rod, slider and through slip table bracing piece reciprocal anchorage, the slider slides and sets up on the slip table bracing piece between support and slip table front support behind the slip table, the speed regulating rod runs through support and slider before the slip table, and the speed regulating rod passes through second ball bearing and sets up in the slider, the one end and the power link mechanism of speed regulating rod are connected, and the other end is fixed with very arm, run through on the support before the slip table be equipped with speed regulating rod mutually perpendicular's axle, epaxial well rocking arm that is fixed with, and well rocking arm is articulated with very arm, and the one end and the axle of long rocking arm are fixed, and the other end is articulated with rocker one end. The device of the utility model is simple in structure, it is convenient to adjust, and it is more smooth-going to adjust the gradient.

Description

Power transmission assembly

Technical Field

The utility model belongs to the technical field of the crops fertilization equips, especially, relate to a power transmission assembly.

Background

A rice transplanter is an agricultural machine for planting rice seedlings in paddy fields, and generally has a traveling part and a planting part towed by the traveling part, the traveling part drives the rice transplanter to travel forward, and the planting part plants the rice seedlings in the paddy field. The rice seedling planting operation is carried out by a rice seedling transplanter, meanwhile, the deep fertilizing combined operation is completed on the side of the rice seedling, which is a generally accepted reasonable agricultural method at present, the power assembly of the current fertilizer applicator matched with the rice seedling planter is complex in structure, does not have the speed regulation function and cannot be well matched with the rice seedling planting action, and in addition, as the power assembly is close to the ground, mud, dust and other impurities are easy to enter the power assembly during working, so that the service life is influenced.

SUMMERY OF THE UTILITY MODEL

In order to solve the technical problem, the utility model aims at providing a power transmission assembly, this power transmission assembly is convenient for adjust fertilizer conveying speed for the fertilizer distributor can be better use with the cooperation of transplanter.

In order to achieve the above purpose, the utility model adopts the following technical scheme:

a power transmission assembly comprises a power link mechanism, a speed regulating mechanism, a long rocker arm and a rocker, wherein the speed regulating mechanism comprises a speed regulating rod, a slider, a sliding table rear support and a sliding table front support which are mutually fixed through a sliding table supporting rod, the slider is arranged on the sliding table supporting rod between the sliding table rear support and the sliding table front support in a sliding way, the speed regulating rod penetrates through the sliding table front support and the slider, the speed regulating rod is arranged in the slider through a second ball bearing, one end of the speed regulating rod is connected with the power link mechanism, the other end of the speed regulating rod is fixed with a lifting arm, a shaft which is mutually vertical to the speed regulating rod is arranged on the sliding table front support in a penetrating way, a middle rocker arm is fixed on the shaft, the middle rocker arm is hinged with the lifting arm, one end of the long rocker arm is fixed with the shaft, the other end of the long rocker arm is hinged with one end, and a ball bearing used for connecting a speed regulating rod is arranged in the small ring, the other end of the transmission connecting rod is provided with a large ring, an eccentric wheel is arranged in the large ring through a first ball bearing, and the two mud guards are respectively fixed on two sides of the eccentric wheel.

As a preferable scheme: the width of the eccentric wheel is larger than that of the large ring, the outer edge of one circle of the fender turns inwards to form a flange, and the width of the eccentric wheel is smaller than the sum of the widths of the large ring and the flange.

As a preferable scheme: an oil chamber for containing lubricating oil is formed in the hollow part of the eccentric wheel, and O-shaped sealing rings are further arranged on two sides of the eccentric wheel.

As a preferable scheme: still include adjusting device, adjusting device includes that both ends set up the lead screw on support and the slip table rear support before the slip table respectively to and pass through screw-thread fit's screw-nut with the lead screw, screw-nut fixes in the slip table, the one end of lead screw still is equipped with adjusting hand wheel, and is equipped with position indicator between adjusting hand wheel and the lead screw.

As a preferable scheme: the position indicator comprises a plurality of coaxially arranged indicating rings, indicating ring teeth are arranged on one of the indicating rings, hand wheel ring teeth are further arranged on the shaft where the adjusting hand wheel and the screw rod are fixed, and the hand wheel ring teeth are meshed with the indicating ring teeth.

As a preferable scheme: and a shaft for fixing the adjusting hand wheel and the screw rod is arranged in parallel with the rotating shafts of the indicating rings.

As a preferable scheme: the sliding table front support is U-shaped, the middle rocker arm is positioned at an opening of the sliding table front support, and a transmission shaft is arranged between the shaft and the long rocker arm through a coupler.

The utility model discloses a power input end and power take off end are connected respectively at the both ends of governor lever, and are equipped with the slider through second ball bearing on the governor lever, make governor lever middle part fulcrum position change through the position change of slider on two slip table bracing pieces, and then change the velocity of motion at governor lever both ends and realized the purpose of adjusting fertilizer conveying speed, just the device of the utility model is simple in structure, it is convenient to adjust, and it is more smooth-going to adjust the gradient.

Additionally, the utility model discloses link mechanism's eccentric wheel passes through first ball bearing installation with the transmission connecting rod, and the installation accuracy requirement is lower, and assembles more conveniently, and the fender of eccentric wheel both sides can prevent inside muddy water gets into power link mechanism, has prolonged life.

Drawings

FIG. 1 is an exploded view of the overall structure of a fertilizer applicator;

FIG. 2 is a schematic view of the overall structure of the fertilizer applicator;

FIG. 3 is a schematic view of the overall structure of the front side of the fertilizer box;

FIG. 4 is a schematic side view of the fertilizer box;

FIG. 5 is a cross-sectional view A-A of FIG. 3;

FIG. 6 is a cross-sectional view B-B of FIG. 4;

FIG. 7 is an enlarged view of a portion of FIG. 5 at C;

FIG. 8 is a schematic view of an angle of the fertilizer dosing assembly;

FIG. 9 is a schematic view of another angle of the fertilizer dosing assembly;

FIG. 10 is a schematic view of an angled configuration of the wheel assembly;

FIG. 11 is a schematic view of another angle of the apparatus for driving the fertilizing wheel;

FIG. 12 is a schematic sectional view of the fertilizer metering assembly;

FIG. 13 is a schematic cross-sectional view of the isolator;

FIG. 14 is a schematic structural view of the power transmission assembly;

FIG. 15 is a schematic view of the mounting structure of the power linkage, the speed adjustment mechanism and the adjustment device;

FIG. 16 is a schematic view of the mounting structure of the governor mechanism and the adjustment device;

FIG. 17 is a schematic structural view of a power link;

FIG. 18 is a schematic view of the structure of the adjustment device;

FIG. 19 is an angular schematic of the governor mechanism;

FIG. 20 is a schematic view of another angle of the governor mechanism;

FIG. 21 is a schematic view of an angled configuration of the trenching fertilizer assembly;

FIG. 22 is a schematic view of another angle structure of the ditching fertilizer delivery assembly;

fig. 23 is a schematic structural view of a fertilizer box base.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary and intended to be used for explaining the present invention, and should not be construed as limiting the present invention.

The fertilizer distributor comprises a fertilizer box 1, a fertilizer quantitative conveying assembly 2, a power transmission assembly 3, a ditching fertilizer conveying assembly 4 and a support 5, wherein the fertilizer box 1 and the fertilizer quantitative conveying assembly 2 are respectively arranged at the upper part and the lower part of the support 5, the power transmission assembly 3 drives the fertilizer quantitative conveying assembly 2 to convey fertilizer, and the ditching fertilizer conveying assembly 4 is connected with the fertilizer quantitative conveying assembly 2 through a pipeline.

As shown in fig. 3 to 7 and 23, the fertilizer box 1 includes a box body 11, a lower portion of the box body 11 is closed to form a feed opening 15, two through holes are formed in the bottom of the feed opening 15, a grid 181 is fixed in the through holes, a circle of groove is further formed in the outer side wall of the lower portion of the grid 181, a sealing ring 110 is further clamped in the groove, and the sealing ring 110 extends to the lower end face of the grid 181. A metal baffle plate 19 is further clamped between at least one grid 181 of the grids 181 and the feed opening 15. The bottom surface of the sealing ring 110 is flush with the bottom surface of the feed opening 15. The sealing ring is clamped on the side face of the grid and extends to the bottom of the grid, and is flush with the feed opening, so that the sealing ring is reduced to be in contact with air, the sealing effect is better, the grid is not easy to age, in addition, a metal plate is arranged between the grid and the feed opening as required, the feed passage can be flexibly closed, and the waste of fertilizer is reduced.

The box body 11 is also detachably hinged with a box cover 12 through a hinge 111, a fertilizer box seat 13 used for being hinged with the support 5 is arranged at the lower part of the box body 11, and a movable lock catch 14 used for being matched with a fixing buckle 113 on the support 5 is further arranged on the fertilizer box seat 13. The box cover is detachably connected, the use is more flexible and convenient, and the box body is hinged with the frame body, so that the box body can be turned over and operated, and the use is more convenient.

The side wall of the lower part of the box body 11 is also provided with a photoelectric switch 17 in a clamping way through a sensor seat 16, and the sensor seat 16 is made of rubber. The hinge 111 is used for pulling a hinge, and a binding band 112 for fixing the box cover 12 is further arranged on the box cover 12. The case cover that can make the activity set up is more stable in the setting of bandage, and the use of bandage is also more nimble, installs photoelectric switch through the sensor seat in addition, and the assembly is more convenient.

The fertilizer box base 13 includes a first fixing base 131 fixed to the lower portion of the box body and a second fixing base 132 fixed to the bracket 5, one end of the first fixing base 131 is hinged to one end of the second fixing base 132, a second protruding piece 134 extending upward is further disposed on the second fixing base 132, a first protruding piece 133 is disposed at the bottom of the first fixing base 131, and the first fixing base 131 and the second fixing base 132 are limited in the rotation direction of the hinge shaft by the extrusion of the first protruding piece 133 and the second protruding piece 134. The first tab 133 and the second tab 134 are arranged perpendicular to each other.

The fertilizer box bases 13 are three and are respectively arranged at the two sides and the middle of the bottom of the box body 11, and the movable lock catch 14 is arranged at the other end of the first fixing base 131 of the fertilizer box base 13 at the middle.

As shown in fig. 8, 9 and 12, the fertilizer quantitative conveying assembly 2 includes a fertilizer discharging housing, a fertilizer discharging wheel 23, a fertilizer discharging funnel 26, a fertilizer discharging wheel driving device, a fan housing 27 and a fan, wherein a feed inlet is formed in the upper portion of the fertilizer discharging housing, a fertilizer discharging port is formed in the front end of the fertilizer discharging housing, the feed inlet is communicated with a feed outlet of the fertilizer box 1, the fertilizer discharging funnel 26 is connected to the front end of the lower portion of the fertilizer discharging housing in a clamping manner, the fan housing 27 is fixed to the rear end of the lower portion of the fertilizer discharging housing, a plurality of pipe orifices are formed in the fertilizer discharging funnel 26, the plurality of fans are fixed in the fan housing 27, each fan corresponds to one pipe orifice, and the fertilizer discharging wheel 23 is rotatably arranged in the fertilizer discharging housing through a fertilizer discharging wheel shaft 25 and is. The fertilizer quantitative conveying assembly is provided with the fan through the pipe orifice correspondence of each fertilizer discharging funnel, so that one pipe orifice corresponds to one fan, fertilizer conveying is more stable, the pipe orifices and the fans are in one-to-one correspondence, and the working condition of the fans can be detected to judge whether the corresponding pipe orifices are blocked or not.

The fertilizer discharging shell comprises a fertilizer discharging upper cover 21 and a fertilizer discharging base 22 which are fixed with each other, a valve is further arranged at the inner end of the fertilizer discharging port, a fertilizer discharging pull buckle 28 is hinged to the valve, a limiting column 29 is further fixed at the outer end of the fertilizer discharging port, and the fertilizer discharging pull buckle 28 abuts against the limiting column 29. The arrangement of the valve facilitates the discharge of redundant fertilizer, and the fertilizer discharging pull buckle 28 is matched with the limiting column 29 for use, so that the structure is simple, and the operation is convenient.

The lower part of the fertilizer discharging shell is further provided with a buckling edge 210, the lower part of the fertilizer discharging funnel 26 is provided with a limiting block 212, the fan shell 27 is hinged with a fertilizer discharging funnel pull buckle 211, the upper side of the fertilizer discharging funnel 26 is clamped with the buckling edge 210, and the lower side part of the fertilizer discharging funnel pull buckle 211 is fixed with the limiting block 212 in a buckling mode. The fertilizer discharging funnel adopts a detachable assembly mode, so that the fertilizer discharging funnel can be conveniently detached and timely cleaned when the blockage occurs to the equipment.

The fertilizer brush 209 is arranged on one side of the fertilizer discharging wheel 23 in the fertilizer discharging shell, the fertilizer brush 209 is made of rubber, the fertilizer discharging wheel 23 is not damaged, fertilizer can be prevented from being blocked in the fertilizer discharging shell, and a plurality of air holes 213 are formed in the bottom of the fan shell 27.

As shown in fig. 10 and 11, the fertilizer discharging wheel driving device includes an isolator 201, a fertilizer discharging wheel driving shaft 202, a driving gear 271, a fertilizer discharging gear 24, a gear seat 272 and an operating mechanism, the isolator 201 is fixed at one end of the fertilizer discharging wheel driving shaft 202, the fertilizer discharging gear 24 is fixed at one end of the fertilizer discharging wheel shaft 25, the driving gear 271 is arranged on the fertilizer discharging wheel driving shaft 202 through the gear seat 272, a limit ring is further arranged on the fertilizer discharging wheel driving shaft 202, a spring 273 is arranged between the limit ring and the gear seat 272, the operating mechanism is fixed on the support 5 and drives the gear seat 272 to slide on the fertilizer discharging wheel driving shaft 202, so that the driving gear 271 and the fertilizer discharging gear 24 are engaged with or separated from each other. The fertilizer wheel driving device is arranged, so that the rotation and stop control of the fertilizer wheel are more convenient.

The operating mechanism comprises a first driving lever 261 and a second driving lever 262, one ends of which are hinged with each other through a hinge column 263, the middle parts of the first driving lever 261 and the second driving lever 262 are rotatably arranged on a fixing plate 266 fixed with the bracket 5 through a rotating shaft 264, one end of a gear seat 272 is provided with a circle of convex edge, and the other end of the second driving lever 262 is abutted against the convex edge of the gear seat 272.

As shown in fig. 13, the isolator 201 includes a fixed sleeve 203 fixed to the bracket 5, a movable sleeve 204 connected to the power mechanism, and an inner shaft 205, the fixed sleeve 203 and the movable sleeve 204 are respectively disposed outside the inner shaft 205 through a one-way bearing 206, the inner shaft 205 is hollow to form an oil storage chamber, one end of the inner shaft 205 is fixed with an aluminum oil pointer 207, the other end of the inner shaft is fixed with an inner hexagon bolt 208, and the fertilizer discharging wheel driving shaft 202 is inserted into the inner hexagon bolt 208. The inside oil storage chamber that is equipped with of isolator 201, the lubrication between the spare part is more abundant, and life is longer, and the aluminium oil pointer of isolator one end is convenient for observe the condition of oil storage chamber, and the hexagon socket head cap screw of the other end is convenient for arrange inserting of fertile wheel drive shaft 202 and is established, and assembly production is more nimble.

As shown in fig. 14 to 20, the power transmission assembly 3 includes a power link mechanism, a speed adjusting mechanism, a long rocker arm 312 and a rocker 313, the speed adjusting mechanism includes a speed adjusting rod 33, a sliding block 35, and a sliding table rear support 314 and a sliding table front support 38 fixed to each other through the sliding table support rod 37, the sliding block 35 is slidably disposed on the sliding table support rod 37 between the sliding table rear support 314 and the sliding table front support 38, the speed adjusting rod 33 penetrates through the sliding table front support 38 and the sliding block 35, the speed adjusting rod 33 is disposed in the sliding block 35 through a second ball bearing 331, one end of the speed adjusting rod 33 is connected to the power link mechanism, the other end is fixed to a lifter 315, a shaft 391 perpendicular to the speed adjusting rod 33 is disposed on the sliding table front support 38, a middle rocker arm 39 is fixed to the shaft 391, the middle rocker arm 39 is hinged to the lifter 315, one end of the long rocker arm 312 is fixed to the shaft 391, the other end is hinged to, the other end of the rocker 313 is hinged with the movable sleeve 204 of the isolator 201.

The power input end and the power output end are connected respectively at the both ends that the power transmission assembly passes through the governor lever, and are equipped with the slider through the second ball bearing on the governor lever, make governor lever middle part fulcrum position change through the position change of slider on two slip table bracing pieces, and then change the velocity of motion at governor lever both ends and realized the purpose of adjusting fertilizer conveying speed, and it is more smooth-going to adjust the gradient.

The sliding table front support 38 is U-shaped, the middle rocker arm 39 is located at an opening of the sliding table front support 38, and a transmission shaft 311 is further arranged between the shaft 391 and the long rocker arm 312 through a coupler.

The power connecting rod mechanism comprises a transmission connecting rod 31 and fenders 32, wherein one end of the transmission connecting rod 31 is provided with a small ring 319, a ball bearing used for connecting a speed regulating rod 33 is arranged in the small ring 319, the other end of the transmission connecting rod 31 is provided with a large ring 323, an eccentric wheel 317 is arranged in the large ring 323 through a first ball bearing 318, the two fenders 32 are respectively fixed on two sides of the eccentric wheel 317, and a power output shaft is further inserted in the eccentric wheel.

The eccentric wheel and the transmission connecting rod are installed through the first ball bearing, the installation precision requirement is low, the assembly is more convenient, and in addition, mud water can be prevented from entering the power connecting rod mechanism through mud guards on two sides of the eccentric wheel, so that the service life is prolonged.

The width of the eccentric wheel 317 is larger than that of the large ring 323, one circle of outer edge of the mudguard 32 is turned inwards to form a flanging 321, and the width of the eccentric wheel 317 is smaller than the sum of the widths of the large ring 323 and the flanging 321. An oil chamber for accommodating lubricating oil is formed in the eccentric wheel 317 in a hollow manner, and O-shaped sealing rings are further arranged on two sides of the eccentric wheel 317.

The power transmission assembly 3 further comprises an adjusting device, the adjusting device comprises a screw rod 34 and a screw nut 341, the two ends of the screw rod 34 are respectively arranged on the sliding table front support 38 and the sliding table rear support 314, the screw nut 341 is in threaded fit with the screw rod 34, the screw nut 341 is fixed in the sliding block 35, one end of the screw rod is further provided with an adjusting hand wheel 310, and a position indicator is arranged between the adjusting hand wheel and the screw rod. The adjusting mode of the screw rod and the nut has higher adjusting precision, and the arrangement of the position indicator further improves the precision of adjusting the speed of the power transmission assembly.

The position indicator comprises a plurality of coaxially arranged indicating rings, wherein one indicating ring is provided with indicating ring teeth 3161, the shaft for fixing the adjusting hand wheel 310 and the screw rod 34 is also provided with hand wheel ring teeth 3101, and the hand wheel ring teeth 3101 are meshed with the indicating ring teeth 3161. The shaft of the adjusting handwheel 310 fixed with the screw rod 34 is arranged in parallel with the rotating shafts of the indicating rings.

As shown in fig. 21 and 22, the ditching fertilizer delivery assembly 4 includes a ditcher bracket 41, a welding shaft 43, ditching plates 44 and a fertilizer delivery pipe 47, the ditcher bracket 41 is fixed to the welding shaft 43 through two connecting pipes 42 arranged at intervals, the ditching plates 44 are arranged at intervals at the lower part of the welding shaft 43, one end of the fertilizer delivery pipe 47 is fixed to one side of the ditching plates 44, an arc-shaped through groove 46 is formed in one side of the ditching plates 44 fixed to the fertilizer delivery pipe 47, and the other end of the fertilizer delivery pipe 47 is fixed to the opening of the fertilizer discharge funnel 26. The fertilizer conveying pipe is arranged on the ditching plate, so that the fertilizer can be more accurately released to the rice transplanting position, and the fertilizer conveying pipe and the ditching plate are clamped through the arc-shaped through groove, so that the operation is more convenient.

The ditching plate 44 is integrally wedge-shaped, trapezoidal notches 45 are respectively arranged on two side faces of the ditching plate 44, the ditcher bracket 41 is a square tube, the welding shaft 43 is a round tube, and the length of the welding shaft 43 is smaller than that of the ditcher bracket 41. The wedge-shaped hook opening plate reduces resistance and is higher in efficiency.

It should be noted that the above embodiments are merely representative examples of the present invention. The utility model can also have a plurality of deformations. Any simple modification, equivalent changes and modifications made to the above embodiments according to the essence of the present invention should be considered as belonging to the protection scope of the present invention.

Claims

1. A power transfer assembly, characterized by: the speed regulation mechanism comprises a power connecting rod mechanism, a speed regulation mechanism, a long rocker arm (312) and a rocker (313), wherein the speed regulation mechanism comprises a speed regulation rod (33), a sliding block (35), a sliding table rear support (314) and a sliding table front support (38) which are mutually fixed through a sliding table support rod (37), the sliding block (35) is arranged on the sliding table support rod (37) between the sliding table rear support (314) and the sliding table front support (38) in a sliding way, the speed regulation rod (33) penetrates through the sliding table front support (38) and the sliding block (35), the speed regulation rod (33) is arranged in the sliding block (35) through a second ball bearing (331), one end of the speed regulation rod (33) is connected with the power connecting rod mechanism, the other end of the speed regulation rod is fixed with a lifting arm (315), a shaft (391) which is mutually vertical to the speed regulation rod (33) is arranged on the sliding table front support (38) in a penetrating way, a middle rocker arm (39) is fixed on the shaft (391), and, one end of the long rocker arm (312) is fixed with the shaft (391), the other end of the long rocker arm is hinged with one end of the rocker (313), the power connecting rod mechanism comprises a transmission connecting rod (31) and a mudguard (32), one end of the transmission connecting rod (31) is provided with a small ring (319), a ball bearing used for being connected with the speed adjusting rod (33) is arranged in the small ring (319), the other end of the transmission connecting rod (31) is provided with a large ring (323), an eccentric wheel (317) is arranged in the large ring (323) through a first ball bearing (318), and the two mudguards (32) are respectively fixed on two sides of the eccentric wheel (317).

2. A power transfer assembly as set forth in claim 1, wherein: the width of the eccentric wheel (317) is larger than that of the large ring (323), the outer edge of one circle of the mudguard (32) is turned inwards to form a flanging (321), and the width of the eccentric wheel (317) is smaller than the sum of the widths of the large ring (323) and the flanging (321).

3. A power transfer assembly as set forth in claim 1, wherein: an oil chamber for containing lubricating oil is formed in the hollow inner part of the eccentric wheel (317), and O-shaped sealing rings are further arranged on two sides of the eccentric wheel (317).

4. A power transfer assembly as set forth in claim 1, wherein: still include adjusting device, adjusting device includes that both ends set up lead screw (34) on slip table front support (38) and slip table after-poppet (314) respectively to and lead screw nut (341) through screw-thread fit with lead screw (34), lead screw nut (341) are fixed in slider (35), the one end of lead screw still is equipped with adjusting hand wheel (310), and is equipped with position indicator between adjusting hand wheel and the lead screw.

5. A power transfer assembly as set forth in claim 4, wherein: the position indicator comprises a plurality of coaxially arranged indicating rings, indicating ring teeth (3161) are arranged on one indicating ring, hand wheel ring teeth (3101) are further arranged on a shaft for fixing the adjusting hand wheel (310) and the screw rod (34), and the hand wheel ring teeth (3101) are meshed with the indicating ring teeth (3161).

6. A power transfer assembly as set forth in claim 5, wherein: and a shaft of the adjusting hand wheel (310) fixed with the screw rod (34) is arranged in parallel with the rotating shafts of the indicating rings.

7. A power transfer assembly as set forth in claim 1, wherein: the sliding table front support (38) is U-shaped, the middle rocker arm (39) is positioned at an opening of the sliding table front support (38), and a transmission shaft (311) is further arranged between the shaft (391) and the long rocker arm (312) through a coupler.