Cam connecting rod pushing mechanism for cigarette packaging machine

Abstract

The invention discloses a cam connecting rod pushing mechanism used in a cigarette packaging machine. The cam connecting rod pushing mechanism comprises a crank, a connecting rod, a connecting frame rod, a sliding block, a variable-length rack and a cam. According to the cam connecting rod pushing mechanism, a given point on a connecting rod plane can move according to a preset track. The linear part in the track is used for completing material pushing, and meanwhile the curve part in the track can be used for automatically avoiding the materials.

Description

Technical Field

[0001] The invention relates to the field of packaging machinery, and in particular to a cam connecting rod pushing mechanism used in a cigarette packaging machine. Background Art

[0002] In the production of cigarettes, a very important process is to pack cigarette boxes with film. During the film packing process, the cigarette boxes need to be pushed into the film packing machine one by one. Figure 1 The figure shows the working diagram of the pusher mechanism in the cigarette packaging machine. The cigarette strips 2 composed of cigarette boxes 3 are continuously input by the conveying mechanism, and the pusher head 1 of the pusher mechanism needs to be used to send the cigarette boxes 3 to the packaging station. In this process, the motion trajectory of the pusher head 1 is generally a straight line. When the pusher head 1 returns, it needs to avoid the cigarette strips 2, so its motion trajectory is a curve, without special requirements, generally a semicircular arc. It can be seen that in order to complete the pushing task, the pusher head 1 needs to move according to the specified trajectory. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a cam-connecting rod pusher mechanism capable of realizing a specified motion trajectory. In order to solve the above technical problem, the technical solution provided by the present invention is as follows:

[0004] A cam-connecting rod pushing mechanism for a cigarette packaging machine comprises a crank, a connecting rod, a connecting rod, a fixed slide rail, a cam push rod, a cam and a frame. The cam is fixedly connected to the crank to push the cam push rod to reciprocate along the frame. The length of the crank is 20 mm, the length of the connecting rod is 47 mm, the length of the connecting rod is 476 mm, the distance from point E on the connecting rod plane to hinge B is 133 mm, the length of the cam push rod is 400 mm, the angle between the line from hinge B to point E and the direction of the connecting rod is -0.144 rad, the installation angle of the frame is 0.162 rad, the x-axis coordinate of the fixed hinge A of the crank is 41 mm, and the y-axis coordinate is -112 mm.

[0005] Preferably, when the cam-link pushing mechanism passes through 20 precision control points, the lengths of the frame are 476.1mm, 476.5mm, 476.1mm, 475.9mm, 476.1mm, 476.1mm, 476.0mm, 476.1mm, 475.9mm, 476.0mm, 475.9mm, 475.8mm, 475.4mm, 476.1mm, 476.7mm, 476.2mm, 476.2mm, 476.3mm, 476.0mm, and 476.4mm respectively.

[0006] The cam connecting rod material pushing mechanism of the present invention can make a given point on the connecting rod plane move along a predetermined track, use the straight line part in the track to complete the material pushing, and use the curved part in the track to automatically avoid the material, thereby realizing high-speed material pushing. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 , schematic diagram of the pushing mechanism working process.

[0008] Figure 2 , schematic diagram of the planar four-bar mechanism.

[0009] Figure 3 , schematic diagram of a two-degree-of-freedom five-bar mechanism.

[0010] Figure 4 , schematic diagram of the cam-linkage mechanism.

[0011] Figure 5 , geometric parameter diagram of the cam-connecting rod pushing mechanism described in the present invention.

[0012] Figure 6 , the target motion trajectory diagram of the push head when the packaging object is GDX-1 type hard-pack small box cigarettes.

[0013] Figure 7 , when the packaging object is GDX-1 type hard pack small box cigarettes, the target motion trajectory of the push head and the motion trajectory of point E on the connecting rod plane.

[0014] Figure 8 , target motion trajectory diagram of the pusher head when the packaging objects are hard-packed slim cigarettes and small-box cigarettes.

[0015] Fig. 9 , the target motion trajectory of the push head and the motion trajectory of point E on the connecting rod plane when the packaging objects are hard-packed slim cigarettes and small-box cigarettes. DETAILED DESCRIPTION

[0016] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0017] like Figure 2 The figure shows a planar four-bar mechanism. The four hinges of the four-bar mechanism are A, B, C, and D. There is a specified point E on the connecting rod plane of the four-bar mechanism. Although point E on the connecting rod of the planar four-bar mechanism can generate a variety of motion trajectories, the four-bar mechanism can only accurately fit 5 points. Figure 3 As shown in the figure, when a slider is added to the four-bar mechanism, the planar four-bar mechanism can be transformed into a two-degree-of-freedom five-bar mechanism. However, the two-degree-of-freedom five-bar mechanism requires two independent active parts to meet the uniqueness requirement of the mechanism movement. By adding a cam fixedly connected to the active crank in the two-degree-of-freedom five-bar mechanism, the cam mechanism is used to close the two-degree-of-freedom five-bar mechanism, so that it can be transformed into a Figure 4 The four-bar mechanism with variable frame length shown in the figure. The frame length parameter can be obtained from inverse kinematics. By expressing the frame length as a function of the crank angle, a single-degree-of-freedom cam-link mechanism with a precise cam profile is formed.

[0018] Therefore, the present invention proposes Figure 4 The cam-connecting rod mechanism is used as the prototype mechanism of the pusher mechanism. The mechanism includes a crank 4, a connecting rod 5, a connecting rod 6, a fixed slide rail 7, a cam push rod 8, a cam 9, and a frame 10. The cam 9 is fixedly connected to the crank 4 to push the cam push rod 8 to move back and forth along the frame 10.

[0019] like Figure 5 As shown, let the length of crank 4 be a, the length of connecting rod 5 be b, the length of connecting rod 6 be c, the length of frame 10 be d, the distance from point E on the plane of connecting rod 5 to hinge B be e, the length of cam push rod 8 be l, and the angle between the line from hinge B to point E and the direction of connecting rod 5 be θ E , the installation angle of the rack 10 is θ D , the rotation angle of crank 4 is θ A , the coordinate of the fixed hinge A of crank 4 is x A ,y A , the coordinates of the precision control points on the target trajectory are From the plane geometry relationship, we know that the Cartesian coordinates of point E on the connecting rod 5 plane can be expressed as: x E =x A +a·cos(θ A +θ D )+e·cos(θ B +θ E +θ D ) y E =y A +a·sin(θ A +θ D )+e·sin(θ B +θ E +θ D ) in, The rod lengths a, b, c, d of the cam-link pusher mechanism, the distance e from point E to hinge B, and the direction angle θ E , the coordinate x of the fixed hinge A A ,y A , installation angle θ D , crank angle θA , should satisfy the equation is the objective function, equation is the constrained optimization equation, and the radius of each point on the contour line of cam 9 should satisfy the equation, R(θ A )=d(θ A )-l, in the constraint equation [γ 0 ] is the allowable transmission angle.

[0020] In order to ensure the transmission characteristics of the mechanism, the transmission angle [γ 0 ] should be less than 30 degrees. 0 ] When the angle is greater than 30 degrees, the transmission performance of the cam-link pusher mechanism decreases significantly.

[0021] In the design of the cam-link pusher mechanism, when the packaging object is a GDX-1 type hard-pack small box cigarette, the size of the cam-link pusher mechanism and the contour line of the cam can be determined according to the above equation. The length, width and height dimensions of the GDX-1 type hard-pack small box cigarette are 86mm, 54.86mm and 22.45mm respectively. According to the size of the cigarette box, the target motion trajectory of the pusher head 1 is determined as follows: Figure 6 The target motion trajectory consists of three parts. The first part is a straight line part, which is used to control the push head 1 to move horizontally at a uniform speed; the second part is a short arc part, which is used to control the push head 1 to slowly descend to avoid the position of the cigarette box 3 changing due to the rapid descent speed; the third part is a long arc curve part, which is used to control the push head 1 to quickly retreat and avoid the cigarette rod 2. In order to achieve the above requirements, 20 precision control points are distributed on the target motion trajectory.

[0022] There are 20 precision control points distributed on the trajectory curve. The motion trajectory between precision control points 2 to 7 is a horizontal straight line, and the distances between precision control points 2 to 7 are equal, which is used to control the push head 1 to move horizontally at a uniform speed. The motion trajectory between precision control points 7 to 9 is a short arc line, which controls the push head 1 to separate slowly from the cigarette box to avoid affecting the position of the cigarette box 3 due to the separation speed being too fast. The motion trajectory between precision control points 9 to 20 is a circular arc curve, which is used for the rapid retreat of the push head 1. Using the coordinates of the above precision control points and the established cam-connecting rod pusher mechanism optimization equation, it can be determined that the length of crank 4 is equal to 20mm, the length of connecting rod 5 is equal to 47mm, the length of connecting rod 6 is equal to 476mm, the distance from point E on the plane of connecting rod 5 to hinge B is equal to 133mm, the length of cam push rod 8 is equal to 400mm, the angle between the line from hinge B to point E and the direction of connecting rod 5 is equal to -0.144rad, the installation angle of frame 10 is equal to 0.162rad, the x-axis coordinate of the fixed hinge A of crank 4 is equal to 41mm, and the y-axis coordinate is equal to -11 2mm, when the cam-link pushing mechanism passes through 20 precision control points, the lengths of the frame 10 are 476.1mm, 476.5mm, 476.1mm, 475.9mm, 476.1mm, 476.1mm, 476.0mm, 476.1mm, 475.9mm, 476.0mm, 475.9mm, 475.8mm, 475.4mm, 476.1mm, 476.7mm, 476.2mm, 476.2mm, 476.3mm, 476.0mm, and 476.4mm respectively.

[0023] According to the determined length dimensions of the rack 10 at the 20 precision control points, the equation R(θ A )=d(θ A )-1 can calculate the profile curve of cam 9. The crank 4 is driven at a constant speed, and the motion trajectory of point E on the plane of connecting rod 5 is obtained by motion simulation as follows: Figure 7 shown. Figure 7 The average error between the trajectory of point E on the plane of the middle link 5 and the 20 precision control points is only 1 mm, indicating that the cam-link mechanism can be used in the pushing work of GDX-1 type hard-pack small box cigarettes.

[0024] When the packaging object is a hard-packed slim cigarette, since the size of the hard-packed slim cigarette box is large, the hard-packed slim cigarette and Tianxia small box cigarette produced by Hunan China Tobacco Company are taken as an example to determine the size of the cam connecting rod push mechanism and the contour line of the cam according to the above equation. The length, width and height dimensions of the hard-packed slim cigarette and Tianxia small box cigarette boxes are 101mm, 55mm and 12.7mm respectively. According to the size of the cigarette box, the target motion trajectory of the push head is determined as follows Figure 8The trajectory shown. There are 20 precision control points distributed on the trajectory curve. The motion trajectory between precision control points 2 to 7 is a horizontal straight line, and the distances between precision control points 2 to 7 are equal, which is used to control the push head 1 to make horizontal uniform linear motion. The motion trajectory between precision control points 7 to 9 is a short arc line, which controls the push head 1 to separate slowly from the cigarette box 3 to avoid lifting the cigarette box due to too fast separation speed. The motion trajectory between precision control points 9 to 20 is a circular arc curve, which is used for the rapid retreat of the push head 1.

[0025] Using the coordinates of the above precision control points and the established cam-connecting rod pusher mechanism optimization equation, it can be determined that the length of crank 4 is 31.9 mm, the length of connecting rod 5 is 280.9 mm, the length of connecting rod 6 is 133.5 mm, the distance from point E on the plane of connecting rod 5 to hinge B is 367.6 mm, the length of cam push rod 8 is 300 mm, the angle between the line from hinge B to point E and the direction of connecting rod 5 is 0.052 rad, the installation angle of frame 10 is -0.853 rad, the x-axis coordinate of fixed hinge A of crank 4 is -293.3 mm, and the y-axis coordinate is Equal to -164.74mm. When the cam-link pushing mechanism passes through 20 precision control points, the lengths of the frame 10 are 350.4mm, 349.3mm, 350.1mm, 350.6mm, 350.5mm, 350.3mm, 350.4mm, 350.4mm, 350.9mm, 350.5mm, 350.6mm, 350.3mm, 350.2mm, 348.8mm, 349.1mm, 350.8mm, 352.3mm, 352.5mm, 351.7mm, and 350.6mm respectively.

[0026] According to the determined length dimensions of the rack 10 at the 20 precision control points, the equation R(θ A )=d(θ A )-1 can calculate the profile curve of cam 9. The crank 4 is driven at a constant speed, and the motion trajectory of point E on the plane of connecting rod 5 is obtained by motion simulation as follows: Fig. 9 shown. Fig. 9 The average error between the trajectory of point E on the plane of the middle link 5 and the 20 precision control points is only 2.3 mm, indicating that the cam-link mechanism can be used in the pushing work of hard-pack thin cigarettes and small-box cigarettes.

[0027] The above is a detailed description of the implementation of the present invention through specific embodiments in conjunction with the accompanying drawings, but the present invention is not limited to the above implementation, and various changes can be made to it within the knowledge of ordinary technicians in this field. Therefore, the protection scope of the present invention is not limited to the above.

Claims

1. A cam-connecting rod pushing mechanism for a cigarette packaging machine, comprising a crank (4), a connecting rod (5), a connecting rod (6), a fixed slide rail (7), a cam push rod (8), a cam (9), and a frame (10), wherein the cam (9) is fixedly connected to the crank (4) and pushes the cam push rod (8) to move back and forth along the frame (10), and is characterized in that: The length of the crank (4) is 20 mm, the length of the connecting rod (5) is 47 mm, the length of the connecting rod (6) is 476 mm, the distance from point E on the plane of the connecting rod (5) to the hinge B is 133 mm, the length of the cam push rod (8) is 400 mm, the angle between the line from the hinge B to point E and the direction of the connecting rod (5) is -0.144 rad, the installation angle of the frame (10) is 0.162 rad, the x-axis coordinate of the fixed hinge A of the crank (4) is 41 mm, and the y-axis coordinate is -112 mm.

2. The cam-link pusher mechanism according to claim 1, characterized in that: When the cam connecting rod pushing mechanism passes through 20 precision control points, the lengths of the frame (10) are 476.1mm, 476.5mm, 476.1mm, 475.9mm, 476.1mm, 476.1mm, 476.0mm, 476.1mm, 475.9mm, 476.0mm, 475.9mm, 475.8mm, 475.4mm, 476.1mm, 476.7mm, 476.2mm, 476.2mm, 476.3mm, 476.0mm, and 476.4mm respectively.

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