阅读说明：本技术 一种塑料袋自动打结机 (Automatic knotter for plastic bag ) 是由 杨俊红 程达 赵亚利 陈天聪 全赛 杨冰莹 吕昱权 杨梓梅 林朝阳 程元华 唐嘉 于 2020-04-10 设计创作，主要内容包括：本发明涉及一种塑料袋自动打结机,包括工作台、动力机构、臂部连杆机构和腕部换置机构,所述工作台的边角处开设有四个圆弧槽,工作台下方两侧对称设置有竖向滑杆；所述工作台下方设置所述动力机构；所述臂部连杆机构并列设置在工作台的两侧,每侧的臂部连杆机构包括对称设置的两个连杆件,每个所述连杆件下部置于工作台下方与所述动力机构连接,连杆件中部通过偏转杆沿所述圆弧槽移动,连杆件上部置于工作台上方连接有支架；所述工作台两侧相应的两连杆件之间设置所述支架,两个支架上均设置所述腕部换置机构。本发明结构合理,采用机械化操作,不仅可以加快打结的速度,提高效率,还可减少人工成本,具有良好的实用性。(The invention relates to an automatic knotter for plastic bags, which comprises a workbench, a power mechanism, an arm connecting rod mechanism and a wrist replacing mechanism, wherein four arc grooves are formed at the corners of the workbench, and vertical sliding rods are symmetrically arranged on two sides below the workbench; the power mechanism is arranged below the workbench; the arm connecting rod mechanisms are arranged on two sides of the workbench in parallel, the arm connecting rod mechanism on each side comprises two symmetrically arranged connecting rod pieces, the lower part of each connecting rod piece is arranged below the workbench and connected with the power mechanism, the middle part of each connecting rod piece moves along the arc groove through a deflection rod, and the upper part of each connecting rod piece is arranged above the workbench and connected with a support; the support is arranged between the two corresponding connecting rod pieces on the two sides of the workbench, and the wrist replacing mechanism is arranged on the two supports. The knotting machine is reasonable in structure, adopts mechanical operation, can accelerate the knotting speed, improve the efficiency, reduce the labor cost and has good practicability.)

1. An automatic knotter for plastic bags is characterized by comprising a workbench (1), a power mechanism, an arm connecting rod mechanism and a wrist replacing mechanism, wherein four arc grooves (2) are formed at the corners of the workbench (1), and vertical sliding rods (3) are symmetrically arranged on two sides below the workbench (1);

the power mechanism is arranged below the workbench (1) and is positioned between the sliding rods (3) on the two sides;

the arm connecting rod mechanisms are arranged on two sides of the workbench (1) in parallel, the arm connecting rod mechanism on each side comprises two symmetrically arranged connecting rod pieces, the lower part of each connecting rod piece is arranged below the workbench (1) and connected with the power mechanism, the middle part of each connecting rod piece moves along the arc groove (2) through a deflection rod (4), and the upper part of each connecting rod piece is arranged above the workbench (1) and connected with a support;

the support is arranged between the two corresponding connecting rod pieces on the two sides of the workbench (1), the wrist replacing mechanisms are arranged on the two supports, and the wrist replacing mechanisms are distributed oppositely.

2. The automatic knotter for plastic bags according to claim 1, wherein the power mechanism comprises a motor frame (501) arranged on the workbench (1), a transmission motor (502) arranged on the motor frame (501), a gear shaft (503) rotatably arranged between the two sliding rods (3), cranks (504) arranged at two ends of the gear shaft (503), a connecting rod (505) and a slider (506) sliding up and down along the sliding rods (3);

the transmission motor (502) is in tooth transmission with the gear shaft (503), two ends of the gear shaft (503) respectively penetrate through the sliding rod (3) to be connected with the crank (504), the sliding block (506) is sleeved on the sliding rod (3), and two ends of the connecting rod (505) are respectively hinged with the crank (504) and the sliding block (506).

3. The automatic knotter for plastic bags according to claim 2, wherein two of said link members are staggered, each of said link members comprising a big arm link (601), a big arm (602), a link arm (603), a small arm (604), and a wrist link (605);

the middle part of the large arm (602) moves along the arc groove (2) through the deflection rod (4), the lower part of the large arm (602) is connected with the sliding block (506) through the large arm connecting rod (601), the lower part of the connecting arm (603) is hinged on the workbench (1), the upper part of the connecting arm (603) penetrates through the large arm (602) to be hinged with the small arm (604), the upper part of the small arm (604) penetrates through the large arm (602), and the wrist connecting rod (605) is arranged between the small arm (604) and the large arm (602).

4. The automatic knot tying machine for the plastic bags according to claim 3 is characterized in that the upper parts of the large arms (602) are bent inwards, the large arms (602) of the two connecting rod pieces on one side of the workbench (1) are distributed in an × shape after being bent, the upper parts of the large arms (602) are provided with limiting grooves, the cross sections of the connecting arm (603) are in a [ "shape, the upper parts of the connecting arm (603) penetrate through the limiting grooves, the lower parts of the small arms (604) are arranged in the connecting arm (603) and hinged with the bent parts of the upper parts of the connecting arm (603), and the upper parts of the small arms (604) penetrate through the limiting grooves to be connected with the wrist connecting rods (605).

5. The automatic knotter for plastic bags according to claim 4, wherein tension springs (7) are arranged between the upper part of the sliding rod (3) and the lower part of the large arm (602) and between the upper part of the large arm (602) and the upper part of the connecting arm (603).

6. The automatic knotter for plastic bags according to claim 3, characterized in that the bracket is arranged between corresponding wrist links (605) at two sides of the working platform (1), the bracket comprises a front frame (801) and a rear frame (802), and the wrist replacement mechanism is arranged between the front frame (801) and the rear frame (802).

7. The automatic knotter for plastic bags according to claim 6, characterized in that the wrist replacing mechanism comprises a stepping motor (901), a case cover (902), a replacing case (903), a replacing disc (904) and a replacing rod (905), the stepping motor (901) is connected with the replacing case (903) through the case cover (902), the replacing case (903) is a hollow cylinder structure with two open ends, the replacing disc (904) is rotatably arranged in the replacing case (903), and the replacing disc (904) is connected with the stepping motor (901);

the edge of the replacing disc (904) is inserted with the replacing rod (905), and the middle part of the replacing disc (904) is elastically connected with a hollow winding shaft (10) for winding the handle of the plastic bag.

8. The automatic knotter for plastic bags according to claim 7, characterized in that one end of the replacement shell (903) is symmetrically provided with a latch (11) and a slot notch (12), the latch (11) and the slot notch (12) on the replacement shell (903) of the wrist replacement mechanism at both sides are distributed in a staggered manner, and the latch (11) is elastically connected with the replacement shell (903);

a plurality of blind holes (13) for inserting the replacement rods (905) are formed in the replacement disc (904) in the circumferential direction, wherein the two blind holes (13) correspond to the positions of the clamping tongues (11) and the clamping groove notches (12) respectively, and the replacement rods (905) for hooking the plastic bag handles are inserted into the blind holes (13) corresponding to the positions of the clamping tongues (11); the replacing rods (905) of the wrist replacing mechanisms on the two sides are distributed in a staggered way.

9. The automatic knotter for plastic bags according to claim 8, wherein the replacing rod (905) is of a reducing cylinder structure, the diameter of the middle part of the replacing rod (905) is smaller than the diameters of the two ends, the circumferential surfaces of the two ends of the replacing rod (905) are respectively provided with a buckle (14), one end of the replacing rod (905) is arranged in the blind hole (13) and is clamped with the clamping tongue (11) through the buckle (14), and the other end of the replacing rod (905) extends out of the blind hole (13).

Technical Field

The invention relates to the technical field of plastic bag knotting, in particular to an automatic knotting machine for plastic bags.

Background

At present, most vegetable processing enterprises adopt the plastic bag to pack vegetables, use the carrot factory as an example, it carries out automatic washing and classification with the carrot that will dig out, artifical bagging-off packing, and finally transport to each supermarket, the bagging-off packing operation of carrot needs a large amount of manual works to accomplish usually, need tie a knot with the plastic bag behind the bagging-off and tie tightly in order to seal, prevent that the carrot from dropping, traditional manual work is tied a knot and is adopted manual operation, not only slow in speed, inefficiency, and need a large amount of labours, waste time and energy, tired scheduling problem easily appears in the workman, and the quality of tying a knot is uneven, there is plastic bag open-ended risk in transporting the in-process, influence the economic benefits of mill.

Disclosure of Invention

The invention provides an automatic knotting machine for plastic bags, which aims to solve the problems of high labor intensity and low efficiency of traditional manual knotting of plastic bags and can replace manual work to carry out efficient automatic knotting on the plastic bags.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

an automatic knotter for plastic bags comprises a workbench, a power mechanism, an arm connecting rod mechanism and a wrist replacing mechanism, wherein four arc grooves are formed in the corners of the workbench, and vertical sliding rods are symmetrically arranged on two sides below the workbench;

the power mechanism is arranged below the workbench and positioned between the sliding rods on the two sides;

the arm connecting rod mechanisms are arranged on two sides of the workbench in parallel, the arm connecting rod mechanism on each side comprises two symmetrically arranged connecting rod pieces, the lower part of each connecting rod piece is arranged below the workbench and connected with the power mechanism, the middle part of each connecting rod piece moves along the arc groove through a deflection rod, and the upper part of each connecting rod piece is arranged above the workbench and connected with a support;

the support is arranged between the two corresponding connecting rod pieces on the two sides of the workbench, the wrist replacing mechanisms are arranged on the two supports, and the wrist replacing mechanisms are distributed oppositely.

Furthermore, the power mechanism comprises a motor frame arranged on the workbench, a transmission motor arranged on the motor frame, a gear shaft rotatably arranged between the two slide bars, cranks arranged at two ends of the gear shaft, a connecting rod and a slide block sliding up and down along the slide bars;

the transmission motor is in transmission with the gear shaft teeth, two ends of the gear shaft penetrate through the sliding rod respectively to be connected with the crank, the sliding block is sleeved on the sliding rod, and two ends of the connecting rod are hinged with the crank and the sliding block respectively.

Furthermore, the two connecting rod pieces are distributed in a staggered mode, and each connecting rod piece comprises a large arm connecting rod, a large arm, a connecting arm, a small arm and a wrist connecting rod;

the middle part of the big arm moves along the arc groove through the deflection rod, the lower part of the big arm is connected with the sliding block through the big arm connecting rod, the lower part of the connecting arm is hinged on the workbench, the upper part of the connecting arm penetrates through the big arm to be hinged with the small arm, the upper part of the small arm penetrates through the big arm, and the wrist connecting rod is arranged between the small arm and the big arm.

Furthermore, the upper part of the big arm is bent inwards, the big arms of the two connecting rod pieces on one side of the workbench are distributed in an × shape after being bent, the upper part of the big arm is provided with a limit groove, the cross section of the connecting frame arm is in a [ -shape, the upper part of the connecting frame arm penetrates through the limit groove, the lower part of the small arm is arranged in the connecting frame arm and is hinged with the bent part of the upper part of the connecting frame arm, and the upper part of the small arm penetrates through the limit groove and is connected with the wrist connecting rod.

Furthermore, tension springs are arranged between the upper part of the sliding rod and the lower part of the large arm and between the upper part of the large arm and the upper part of the connecting frame arm.

Furthermore, the bracket is arranged between the corresponding wrist connecting rods on the two sides of the workbench and comprises a front frame and a rear frame, and the wrist replacing mechanism is arranged between the front frame and the rear frame.

Furthermore, the wrist replacing mechanism comprises a stepping motor, a shell cover, a replacing shell, a replacing disc and a replacing rod, wherein the stepping motor is connected with the replacing shell through the shell cover, the replacing shell is of a hollow cylindrical structure with two open ends, the replacing disc is rotatably arranged in the replacing shell, and the replacing disc is connected with the stepping motor;

the edge of the replacing disc is inserted with the replacing rod, and the middle part of the replacing disc is elastically connected with a hollow winding shaft for winding a plastic bag handle.

Furthermore, one end of the replacement shell is symmetrically provided with a clamping tongue and a clamping groove gap, the clamping tongues and the clamping groove gaps on the replacement shell of the wrist replacement mechanisms on two sides are distributed in a staggered mode, and the clamping tongues are elastically connected with the replacement shell;

a plurality of blind holes for inserting the replacement rods are arranged on the replacement disc in the circumferential direction, wherein two blind holes respectively correspond to the notches of the clamping tongues and the clamping grooves, and the replacement rods for hooking the handles of the plastic bags are inserted in the blind holes corresponding to the notches of the clamping tongues; the replacing rods of the wrist replacing mechanisms on the two sides are distributed in a staggered way.

Furthermore, the replacing rod is of a reducing cylinder structure, the diameter of the middle of the replacing rod is smaller than the diameters of the two ends of the replacing rod, the circumferential surfaces of the two ends of the replacing rod are respectively provided with a buckle, one end of the replacing rod is arranged in the blind hole and is clamped with the clamping tongue through the buckle, and the other end of the replacing rod extends out of the blind hole.

Through the technical scheme, the invention has the beneficial effects that:

the automatic knotting machine is reasonable in structural design, automatic knotting of plastic bags is achieved through combination of a mechanical movement mechanism and single-chip microcomputer control, the defects that an existing manual knotting mode for the plastic bags is slow in operation, low in efficiency, time-consuming and labor-consuming are overcome, and the mechanical part mainly comprises a working table, a power mechanism, an arm connecting rod mechanism and a wrist replacing mechanism.

The power mechanism can provide power for the whole knotting action; the arranged arm connecting rod mechanism can fasten knots formed by the plastic bag handles, the gears and the crank slider mechanism are used for transmission, the plastic bag handles can be shortened when the second knot is knotted, and in order to enable the crank of the power mechanism to still rotate in a whole circle, the big arm is restrained by the arranged tension spring when rotating, so that the knotting machine can work continuously, and the knotting efficiency is improved; the wrist replacing mechanism realizes the replacement of the two handles of the plastic bag by utilizing the mutual rotating fit of the buckle of the replacing rod and the incomplete clamping groove notch of the replacing shell.

The invention can be used for mechanical continuous operation, has the advantages of high knotting efficiency, firm knotting, time and labor saving and strong operation stability, can replace manpower to knot the plastic bag in factories or other occasions where the plastic bag is used for a long time, reduces the labor amount and labor cost of the manpower, and has good practicability.

Drawings

Fig. 1 is a schematic view of the overall structure of an automatic knotter for plastic bags according to the present invention.

Fig. 2 is a plan view of fig. 1 of an automatic knotter for plastic bags according to the present invention.

FIG. 3 is a schematic view of an arm link mechanism of an automatic knotter for plastic bags according to the present invention.

FIG. 4 is a schematic view of a wrist replacing mechanism of an automatic knotting machine for plastic bags according to the present invention.

Fig. 5 is an exploded view of a wrist replacing mechanism of an automatic knotter for plastic bags according to the present invention.

Fig. 6 is a sectional view of a wrist replacing mechanism of an automatic knotter for plastic bags according to the present invention.

Fig. 7 is a schematic view of step 1 in an embodiment of an automatic knotter for plastic bags according to the present invention.

Fig. 8 is an enlarged schematic view of fig. 7 of an automatic knotter for plastic bags according to the present invention.

Fig. 9 is a schematic view of step 2 in an embodiment of an automatic knotter for plastic bags according to the present invention.

Fig. 10 is an enlarged view of the handle hook A of fig. 9 of the automatic knotter for plastic bags according to the present invention.

Fig. 11 is an enlarged view of a single circular hole in step 3 of an embodiment of an automatic knotter for plastic bags according to the present invention.

Fig. 12 is a schematic view of step 4 in an embodiment of an automatic knotter for plastic bags according to the present invention.

Fig. 13 is a sectional view showing the replacement of the both-side replacement bars of the automatic knotter for plastic bags of fig. 12 in accordance with the present invention.

Fig. 14 is a schematic view of step 5 in an embodiment of an automatic knotter for plastic bags according to the present invention.

Fig. 15 is one of the schematic views of step 6 in an embodiment of an automatic knotter for plastic bags according to the present invention.

Fig. 16 is a second schematic view of step 6 of an automatic knotter for plastic bags according to an embodiment of the present invention.

Fig. 17 is one of the steps 7 of the automatic knotter for plastic bags according to the embodiment of the present invention.

Fig. 18 is a second schematic view of step 7 of an automatic knotter for plastic bags according to an embodiment of the present invention.

Fig. 19 is one of the schematic views of step 8 in an embodiment of an automatic knotter for plastic bags according to the present invention.

Fig. 20 is a second schematic view of step 8 of an automatic knotter for plastic bags according to an embodiment of the present invention.

Fig. 21 is a third schematic view of step 8 of the automatic knotter for plastic bags according to the embodiment of the present invention.

FIG. 22 is a fourth schematic view of step 8 in an embodiment of an automatic knotter for plastic bags according to the present invention.

Fig. 23 is a schematic view of step 9 in an embodiment of an automatic knotter for plastic bags according to the present invention.

The reference numbers in the drawings are as follows: 1 is a workbench, 2 is an arc groove, 3 is a sliding rod, 4 is a deflection rod, 501 is a motor frame, 502 is a transmission motor, 503 is a gear shaft, 504 is a crank, 505 is a connecting rod, 506 is a sliding block, 601 is a large-arm connecting rod, 602 is a large arm, 603 is a connecting-rod arm, 604 is a small arm, 605 is a wrist connecting rod, 7 is a tension spring, 801 is a front frame, 802 is a rear frame, 901 is a stepping motor, 902 is a shell cover, 903 is a replacement shell, 904 is a replacement disk, 905 is a replacement rod, 10 is a winding shaft, 11 is a clamping tongue, 12 is a clamping groove gap, 13 is a blind hole and 14 is a buckle.

Detailed Description

The following detailed description of embodiments of the invention refers to the accompanying drawings in which:

as shown in fig. 1 to 23, an automatic knotter for plastic bags comprises a workbench 1, a power mechanism, an arm connecting rod mechanism and a wrist replacing mechanism, wherein four arc grooves 2 are formed at the corners of the workbench 1, vertical slide bars 3 are symmetrically arranged at two sides below the workbench 1, and the slide bars 3 are square bars;

the power mechanism is arranged below the workbench 1 and is positioned between the sliding rods 3 on the two sides;

the arm connecting rod mechanisms are arranged on two sides of the workbench 1 in parallel, the arm connecting rod mechanism on each side comprises two symmetrically arranged connecting rod pieces, the lower part of each connecting rod piece is arranged below the workbench 1 and connected with the power mechanism, a deflection rod 4 is arranged in the middle of each connecting rod piece, the connecting rod pieces move along the arc grooves 2 through the deflection rods 4, and the upper parts of the connecting rod pieces are arranged above the workbench 1 and connected with a support;

the support is arranged between the two corresponding connecting rod pieces on two sides of the workbench 1, the wrist replacing mechanisms are arranged on the two supports, and the wrist replacing mechanisms are distributed oppositely.

In this embodiment, the power mechanism includes a motor frame 501 disposed on the worktable 1, a transmission motor 502 disposed on the motor frame 501, a gear shaft 503 rotatably disposed between the two slide bars 3, a crank 504 disposed at both ends of the gear shaft 503, a connecting rod 505, and a slider 506 vertically sliding along the slide bars 3;

the motor frame 501 is arranged in the middle of the lower part of the workbench 1, the transmission motor 502 is in gear transmission with the gear shaft 503, two ends of the gear shaft 503 penetrate through the sliding rod 3 respectively to be connected with the crank 504, and specifically, the crank 504 is assembled at two ends of the gear shaft 503 through square holes; the slide block 506 is sleeved on the slide rod 3, two ends of the connecting rod 505 are respectively hinged with the crank 504 and the slide block 506, and the crank 504, the connecting rod 505 and the slide block 506 are matched to move to form a crank 504 and slide block 506 mechanism.

In this embodiment, as shown in fig. 3, the two link members are distributed in a staggered manner, each link member includes a large arm link 601, a large arm 602, a link arm 603, a small arm 604 and a wrist link 605, the middle portion of the large arm 602 moves along the arc groove 2 through the deflection rod 4, and can also swing circumferentially around the deflection rod 4 as an axis, the lower portion of the large arm 602 is connected to the slider 506 through the large arm link 601, the lower portion of the link arm 603 is hinged to the workbench 1, the upper portion of the link arm 603 passes through the large arm 602 to be hinged to the small arm 604, the upper portion of the small arm 604 passes through the large arm 602, and the wrist link 605 is hinged between the small arm 604 and the large arm 602.

Specifically, the upper part of the large arm 602 is bent inwards, the large arms 602 of the two connecting rod pieces on one side of the workbench 1 are bent and distributed in an × shape, the upper part of the large arm 602 is provided with a limiting groove, the section of the connecting arm 603 is in a [ -shape, the upper part of the connecting arm 603 passes through the limiting groove, the bent part of the lower part of the connecting arm 603 is hinged on the workbench 1, the bent parts at the upper end and the lower end of the connecting arm 603 form limiting positions, the upper end of the connecting arm 603 can limit the swinging range of the small arm 604, and the lower end of the connecting arm 603 is limited by the workbench 1 so as to control the swinging;

the lower part of the small arm 604 is arranged in the connecting frame arm 603 and hinged with the bending part at the upper part of the connecting frame arm 603, and the upper part of the small arm 604 passes through the limiting groove and is connected with the wrist connecting rod 605.

In order to ensure that the deflection rod 4 in the middle of the large arm 602 can be arranged in the arc groove 2 to slide when the handle of the plastic bag is tensioned, tension springs 7 are respectively arranged between the upper part of the sliding rod 3 and the lower part of the large arm 602 and between the upper part of the large arm 602 and the upper part of the connecting frame arm 603, specifically, the tension spring 7 between the upper part of the sliding rod 3 and the lower part of the large arm 602 can provide tension for the large arm 602, and the tension spring 7 between the upper part of the large arm 602 and the upper part of the connecting frame arm 603 can provide tension for the connecting frame arm;

because the handle of the plastic bag can be shortened when the plastic bag is subsequently knotted for the second time, the big arm 602 and the connecting arm 603 are restrained by the tension spring 7, and the crank 504 and the slider 506 mechanism formed by the crank 504, the connecting rod 505 and the slider 506 can rotate in the whole circle on the premise that the handle of the plastic bag is not broken, so that the knotting machine can continuously work to improve the knotting efficiency.

In the embodiment, the mutual limit of the workbench 1, the large arm 602, the link arm 603, the small arm 604 and the wrist connecting rod 605 is realized, and the mutual conversion of the parallelogram mechanism and the anti-parallelogram mechanism can be realized by the transmission of the gear and the crank 504 and slider 506 mechanism, so that the subsequent actions of replacing the rod 905 and obliquely stretching the plastic bag handle are realized, the working steps are greatly simplified, and the knotting efficiency is improved.

In this embodiment, the bracket is disposed between the corresponding wrist connecting rods 605 on both sides of the workbench 1, the bracket includes a front frame 801 and a rear frame 802, and the wrist replacing mechanism is disposed between the front frame 801 and the rear frame 802.

Specifically, as shown in fig. 4 to 6, the wrist replacing mechanism includes a stepping motor 901, a case cover 902, a replacing case 903, a replacing disc 904 and a replacing rod 905, the rear frame 802 is fastened to the stepping motor 901, the stepping motor 901 is connected to the replacing case 903 through the case cover 902, the front frame 801 is fastened to the replacing case 903, the replacing case 903 is a hollow cylinder structure with openings at both ends, an inner flange is arranged at one end of the replacing case 903, the replacing disc 904 is rotatably arranged in the replacing case 903, the replacing disc 904 is connected to the stepping motor 901, and the replacing disc 904 is limited by the inner flange and the case cover 902 to prevent axial movement thereof;

the edge of the replacing disc 904 is inserted with the replacing rod 905, the middle part of the replacing disc 904 is elastically connected with a hollow winding shaft 10 which is used for winding one end seal of a plastic bag handle, specifically, the replacing disc 904 is elastically connected with the winding shaft 10 through a spring and can stretch out and draw back in the replacing disc 904, and after the two winding shafts 10 of the wrist replacing mechanisms on two sides contact each other in work, the wrist replacing mechanisms on two sides respectively shrink back into the replacing disc 904, so that the large arm 602 continues to fold, and the replacing rod 905 completes replacing action.

Specifically, the inner turning edge at one end of the replacement shell 903 is symmetrically provided with a clamping tongue 11 and a clamping groove gap 12, the clamping tongues 11 and the clamping groove gaps 12 on the replacement shell 903 of the wrist replacement mechanisms at two sides are distributed in a staggered manner, and the clamping tongues 11 are elastically connected with the replacement shell 903 through springs;

the replacement disc 904 is provided with ten blind holes 13 for inserting the replacement rods 905 in an annular direction, wherein two of the blind holes 13 correspond to the positions of the clamping tongues 11 and the clamping groove notches 12 respectively, the replacement rods 905 for hooking the plastic bag handles are inserted into the blind holes 13 corresponding to the positions of the clamping tongues 11, the center of the replacement disc 904 is taken as the center of a circle, the centers of the blind holes 13 from the center of the replacement disc 904 are taken as the radius, and the central angle α formed by connecting the centers of the adjacent two blind holes 13 is 36 degrees.

Correspondingly, the replacing rods 905 of the wrist replacing mechanisms on the two sides are distributed in a staggered manner, specifically, the replacing rods 905 are of a reducing cylinder structure, the diameter of the middle part of the replacing rod 905 is smaller than that of the two ends, the circumferential surfaces of the two ends of the replacing rod 905 are respectively provided with a buckle 14, the size of the buckle 14 is the same as that of the clamping groove gap 12, and the clamping groove gap 12 can enable the replacing rod 905 to be separated from the clamping groove gap 12, so that the replacing action is realized;

one end of the replacing rod 905 is arranged in the blind hole 13 and is clamped with the clamping tongue 11 through the clamping buckle 14, the other end of the replacing rod 905 extends out of the blind hole 13, and the replacing rod 905 arranged in the blind hole 13 can do circular motion along with the rotation of the replacing disc 904, so that the plastic bag handle is wound on the winding shaft 10 to form an annular hole.

Through the mutual cooperation of all parts of the wrist replacing mechanism, the replacing disc 904 rotates once, the connecting rod parts at two sides are folded in opposite directions once, actions such as restraining the replacing rod 905 and releasing the restraining replacing rod 905 can be automatically realized, so that one replacing action is completed, the working steps are greatly simplified, the knotting efficiency is improved, and the requirement on the complexity of a subsequent transmission and control system is also reduced.

The embodiment is also provided with an stm32 single chip microcomputer, the stm32 single chip microcomputer controls the transmission motor 502 and the two stepping motors 901 to enable the transmission motor and the two stepping motors to rotate intermittently, so that parts of the knotting machine are driven to mutually match and move continuously, knotting action is finally achieved, and knotting efficiency is improved.

When the plastic bag is knotted, the operation steps are as follows:

step 1, hanging a plastic bag: as shown in fig. 7-8, two handles of the plastic bag are manually hooked at the middle positions of the replacing rods 905 of the wrist replacing mechanisms at two sides respectively, and two sections of ropes are adopted to replace the two handles of the plastic bag;

step 2, the replacing rod 905 moves to the horizontal position: the transmission motor 502 is started, the gear shaft 503 rotates to drive the crank 504 to rotate anticlockwise, the sliding block 506 moves downwards along the sliding rod 3, the sliding block 506 drives the large arm 602 to swing through the large arm connecting rod 601 to enable the large arm 602 to be folded, the limiting position of the bending position of the lower end of the connecting frame arm 603 is always tightly attached to the workbench 1, the arm connecting rod mechanism is equivalent to an anti-parallelogram mechanism at the moment, the wrist connecting rod 605 tends to be horizontal when the large arm 602 is folded, when the small arm 604 contacts the limiting position of the upper end of the connecting frame arm 603, the wrist connecting rod 605 is just horizontal, as shown in figures 9-10, the replacement rod 905 keeps a horizontal state at the moment, the transmission motor 502 is closed;

step 3, forming an annular hole at the handle once: the stepping motors 901 on the two sides are started at the same time and rotate oppositely, and then the two replacement discs 904 and the respective replacement rods 905 rotate in opposite directions for 324 degrees, so that the left handle and the right handle are driven to rotate in opposite directions for 324 degrees, and the two replacement rods 905 need to be staggered from the position of one blind hole 13 for replacement, so that the stepping motors 901 are controlled by the single chip microcomputer to rotate for 324 degrees;

after the rotation, the two handles are respectively wound on the respective winding shafts 10 to form two annular holes, as shown in fig. 11, at this time, the position of the replacing rod 905 at one side is just rotated to the position of the notch 12 at the other side, which is prepared for the subsequent replacing action, and because the large arm 602 is in the inward folding state at this time, the replacing rod 905 cannot fall off;

step 4, replacing the handle: after the two handles form the annular holes, the two stepping motors 901 are closed, the transmission motor 502 is started again to enable the large arm 602 to be continuously folded, the small arm 604 contacts the upper end limit of the connecting frame arm 603, so the connecting frame arm 603 and the small arm 604 swing together, and the distance between the hinged part of the lower end of the connecting frame arm 603 and the hinged part of the upper end of the small arm 604 is equal to the distance between the two hinged parts of the upper half part of the large arm 602 at the moment, so that a parallelogram mechanism is formed, as shown by dotted lines in fig. 12, when the large arm 602 is folded, the two wrist connecting rods 605 are translated oppositely;

the wrist connecting rods 605 are translated in opposite directions, the two winding shafts 10 are further translated in opposite directions until the end faces are contacted, the winding shafts 10 are forced to retract into the respective replacement discs 904, the large arms 602 are continuously folded, and the two replacement rods 905 are respectively inserted into the blind holes 13 of the opposite replacement discs 904 through the slot notches 12, when the replacement rods 905 are inserted into the blind holes 13 of the replacement discs 904, the clamping tongues 11 on the flanges in the replacement shell 903 can clamp the clamping buckles 14 of the replacement rods 905 to ensure that the replacement rods 905 are fixed, as shown in fig. 13, at this time, the sliding blocks 506 just slide to the lower limit position;

step 5, winding a handle: after the latch 11 buckles the replacing rod 905 in the blind hole 13 of the replacing disk 904 through the buckle 14, the transmission motor 502 continues to rotate, and the crank 504 and the connecting rod 505 slide upwards to slide the sliding block 506 after passing through the aligned position, so that the large arm 602 is opened;

under the action of the tension spring 7, the small arm 604 still clings to the upper end of the connecting arm 603 for limiting, and at the moment, the formed parallelogram mechanism is still formed, so that the two wrist replacing mechanisms can simultaneously and relatively translate and further separate, and the separation can simultaneously pull the opposite replacing rods 905 to move, so that the right side handle is pulled into the annular hole formed by the left side handle, as shown in fig. 14, and similarly, the left side handle is pulled into the annular hole formed by the right side handle, and the winding action of the handle is completed;

step 6, tensioning the handle: the transmission motor 502 continuously drives the sliding block 506 to slide upwards, so that the large arm 602 is continuously opened, and the winding shaft 10 is ejected out under the action of the spring while the large arm 602 is opened to prepare for winding the handle next time;

when the lower end of the connecting frame arm 603 is in limit contact with the workbench 1, the connecting frame arm 603 does not swing any more, the small arm 604 starts to swing by taking the hinged position at the upper end of the connecting frame arm 603 as a center, and at the moment, an anti-parallelogram mechanism is formed, for example, as shown by a dotted line in fig. 15, the wrist connecting rod 605 swings upwards and tends to be vertical while moving outwards, a knot is formed in the process that the two handles are tensioned, and the transmission motor 502 continuously opens the large arm 602, so that the knot is gradually tensioned, as shown in fig. 16;

step 7, transition stage: after the knot is tightened, under the action of the pulling force of the handle of the plastic bag, the hinged position of the upper end of the large arm 602 is fixed, and the transmission motor 502 continues to drive the sliding block 506 to slide upwards, so that the middle deflection rod 4 of the large arm 602 can slide upwards along the arc groove 2, at the moment, the arm connecting rod mechanism is equivalent to the sliding block 506 swing rod mechanism, until the crank 504 and the connecting rod 505 reach the overlapped collinear position, namely, when the sliding block 506 reaches the upper limit position, the middle deflection rod 4 of the large arm 602 slides upwards to the highest point, as shown in fig. 17;

at this time, the transmission motor 502 continues to drive the crank 504 to rotate, so that the slider 506 slides downwards, the deflection rod 4 in the middle of the large arm 602 slides downwards in the arc groove 2 under the action of the tension spring 7 until reaching the limit position, and the arm link mechanism at this time after reaching the limit position is equivalent to an anti-parallelogram mechanism, as shown in fig. 18, the large arm 602 drives the wrist replacing mechanisms at two sides to fold, and the wrist replacing mechanisms drive the plastic bag handles to fold and swing downwards to be horizontal;

step 8, forming an annular hole by the handle for the second time: when the small arm 604 contacts the upper end of the connecting frame arm 603 for limiting, the wrist replacing mechanism is just horizontal, the arm connecting rod mechanism is equivalent to a parallelogram mechanism at this time, the transmission motor 502 is closed, the steps 3-6 are repeated to form a circular hole, replace the lifting handle, wind the lifting handle and tension the lifting handle in order to perform the action of a second rope knot, as shown in fig. 19-22, which is not repeated;

step 9, taking down the plastic bag: when the second knot is tightened and the middle deflection rod 4 of the large arm 602 returns to the original position, the handle of the plastic bag is knotted by two knots, as shown in fig. 23, the third transmission motor 502 is turned off to stop the large arm 602 from being folded, and the plastic bag is taken down from the knotter replacement rod 905, so that the knotting work of one plastic bag can be completed.

The above-described embodiments are merely preferred embodiments of the present invention, and not intended to limit the scope of the invention, so that equivalent changes or modifications in the structure, features and principles described in the present invention should be included in the claims of the present invention.