Cam structure of bundling machine core

Abstract

The utility model discloses a cam structure of a bundling machine core. An independent tape withdrawing area is additionally arranged in the cam structure. The radius of the right cutter cam in the tape withdrawing area is larger than that in the zero position area, and the radius difference between the two is not smaller than 2mm; the radius of the tensioning arm cam in the tape withdrawing area is smaller than the radius of the tensioning arm cam in the binding area, and the radius difference between the two is not smaller than 6 mm. When the machine core cam rotates to a belt withdrawing area, the right cutter jacks up and presses the belt head of the packing belt, the tensioning arm cam does not press down the tensioning arm, at the moment, the binding wheel is not pressed tightly, and when the belt is withdrawn in place at a high speed, the packing belt slides on the belt feeding and withdrawing wheel, so that the maximum binding force during belt withdrawing is limited. According to the technical scheme, an original cam structure is optimized, and the problem that in the prior art, the efficiency is low when a bundling machine core is packaged with small bundling force is well solved under the condition that the cost of the machine core is not increased.

Description

Technical Field

[0001] The utility model relates to a strapping machine, and particularly to a cam structure of a strapping machine core. Background Art

[0002] A strapping machine, also known as a bundling machine, is a device that straps items with strapping bands. The strapping process of the strapping machine consists of several steps such as tape retraction, tensioning, adhesion, tape cutting, and tape feeding. The common strapping machines on the market at present are divided into two categories: semi-automatic and fully automatic. At present, the semi-automatic strapping machine adopting the dual-motor scheme is more energy-saving and has a longer service life compared with the traditional single-motor scheme, and has gradually become the mainstream scheme in the industry. In the dual-motor scheme, the M1 motor is responsible for driving the main shaft of the strapping machine core to rotate, and combines with the cam structure on the main shaft to realize the corresponding strapping actions; the M2 motor is responsible for tape feeding and retracting and strapping actions.

[0003] Since the strapping machine needs to cope with different application scenarios, the strapping force of the strapping machine needs to be adjustable within a large range. For strapping objects such as wood and textiles, a large strapping force is required for strapping, while for strapping objects such as thin-walled pipes and cartons, a smaller strapping force is required, otherwise the strapping objects will be deformed or damaged. At present, the general dual-motor strapping machine adjusts the strapping force by controlling the rotation speed and current of the M2 motor.

[0004] The tape retraction action is to recycle the excess strapping tape so that the strapping tape can fit on the strapping object. Generally, the tape retraction distance is relatively long, so increasing the tape retraction speed can improve the strapping efficiency; the strapping action is to strap the strapping object with a certain force after the strapping tape fits on the strapping object. This action has requirements for the strapping force and requires the strapping force to be dynamically adjustable within a large range. It can be seen that a fast speed is required during tape retraction, and the strapping force cannot be large. In order to avoid too large an impact at the end of high-speed tape retraction, it is necessary to allow the strapping tape to slip on the tape feeding and retracting wheels; while during strapping, in order to make the maximum strapping force large enough, it is necessary to inhibit the strapping tape from slipping.

[0005] In the prior art, the dual-motor strapping machine core integrates both the tape retraction and strapping links in the strapping action in terms of structure. There is no independent tape retraction action. When the M2 motor performs high-speed tape retraction, due to the existence of motor inertia, even if the torque of the motor is adjusted to the minimum, a large impact force will still be generated. Therefore, in order to achieve a lighter strapping force, it is also necessary to limit the speed of the M2 motor to a lower level at the same time. This will seriously affect the strapping efficiency at a small strapping force.

[0006] From the above analysis, it can be seen that there is an urgent need for a strapping machine core scheme that can achieve high-speed strapping at a small strapping force. Summary of the Invention

[0007] To overcome the deficiencies of the prior art, the present utility model proposes a cam structure for a strapping machine core. An independent tape-rewinding position is added to this cam structure for performing the tape-rewinding action. When the machine core is in the tape-rewinding area, the tensioning arm cam does not press down the tensioning arm. At this time, the strapping wheel is not tightened. Therefore, when rewinding at high speed, the generated strapping force is relatively limited.

[0008] To be able to more clearly describe the technical solutions of this application, several concepts described herein are specifically explained here.

[0009] For ease of explanation, the defined rotation direction of the camshaft in this document is the rotation direction when looking from the right side to the left side of the camshaft. That is, the foremost cam piece is the tensioning arm cam, followed by the right knife cam, and the last piece is the left knife cam.

[0010] The angle in the cam structure described in this document is defined as 0 degrees for the cam structure when it rotates to the central position of the zero position area. It is defined in this document that when the cam structure rotates counterclockwise from this position, the angle increases. This application uses the counterclockwise rotation of the machine core cam structure as a setting for explanation, but it does not limit that the present utility model must adopt the way of the cam piece rotating counterclockwise. Technicians in the industry can completely modify it to the clockwise rotation method according to the technical solutions described in this document.

[0011] The high point and low point of the cam described herein refer to the distance between the position on the cam and the center of the camshaft. The distance is close for the low point and far for the high point. Since not all contact points between the cam and the push rod are located above the cam, the high and low points corresponding to some cams are not exactly the same as the high and low in the actual space.

[0012] To achieve the above object, the technical solution adopted by the present utility model is as follows:

[0013] A cam structure for a strapping machine core includes: a right knife cam, a slide cam, a middle knife cam, a heating head cam, a left knife cam, and a tensioning arm cam; the cam structure sequentially includes a zero position area, a tape-rewinding area, a strapping area, a heat-sealing area, a cooling area, a slide opening area, and a slide reset area; the radius of the right knife cam in the tape-rewinding area is greater than the radius in the zero position area, and the radius difference between the two is not less than 2 mm; the radius of the tensioning arm cam in the tape-rewinding area is less than the radius in the strapping area, and the radius difference between the two is not less than 6 mm; the angular difference between the tape-rewinding area and the strapping area is not less than 18 degrees and not greater than 72 degrees. Since the tape-rewinding area is in the front and the strapping area is in the back, the angular difference between the end point of the tape-rewinding area and the start point of the strapping area is the minimum value of the angular difference between these two areas, and this difference is not less than 18 degrees; the angular difference between the start point of the tape-rewinding area and the end point of the strapping area is the maximum value of the angular difference between the two areas, and this difference is not greater than 72 degrees.

[0014] Preferably, in the movement cam structure, the angular range of the zero position area is not less than 4 degrees and not more than 15 degrees; the angular range of the tape rewinding area is not less than 4 degrees and not more than 36 degrees; the angular range of the bundling area is not less than 4 degrees and not more than 36 degrees; the angular range of the heat-sealing area is not less than 60 degrees and not more than 120 degrees; the angular range of the cooling area is not less than 72 degrees and not more than 144 degrees; the range of the slide opening area is not less than 10 degrees and not more than 30 degrees; the range of the slide reset area is not less than 45 degrees and not more than 60 degrees.

[0015] Preferably, the minimum angular difference between the tape rewinding area and the bundling area is 24 degrees, and the maximum angular difference is 56 degrees.

[0016] Preferably, the radius difference between the right knife cam in the tape rewinding area and the zero position area is not less than 2 mm and not more than 5 mm, the radius in the bundling area is greater than or equal to the radius in the tape rewinding area, and the radius difference between the two is not more than 2 mm. The radius difference between the tension arm cam in the tape rewinding area and the bundling area is not less than 6 mm and not more than 14 mm.

[0017] Preferably, the zero position area occupies the interval of -4 degrees to 4 degrees in the cam structure; the tape rewinding area occupies the interval of 16 degrees to 30 degrees in the cam structure; the bundling area occupies the interval of 56 degrees to 70 degrees in the cam structure; the heat-sealing area occupies the interval of 88 degrees to 162 degrees in the cam structure; the cooling area occupies the interval of 182 degrees to 270 degrees in the cam structure; the slide opening area occupies the interval of 288 degrees to 304 degrees in the cam structure; the slide reset area occupies the interval of 304 degrees to 356 degrees in the cam structure.

[0018] Preferably, the radius of the right knife cam in the zero position area is 28 mm ± 1 mm; the radius in the tape rewinding area is 31 mm ± 1 mm; the radius in the bundling area is 32 mm ± 1 mm. The radius of the tension arm cam in the tape rewinding area is 15 mm ± 1 mm, and the radius in the bundling area is 25 mm ± 1 mm.

[0019] Preferably, the slide cam is provided with a slow-down position in the slide reset area, and the angular difference between the tangent of the cam at the slow-down position and the tangent direction of the concentric circle of the cam center axis at the slow-down position is not more than 10 degrees.

[0020] Preferably, the tangent of the slide cam at the slow-down position is tangent to the concentric circle passing through the slow-down position of the camshaft.

[0021] Preferably, the distance between the edge of the cam at the slow-down position and the center axis is 27 mm to 29 mm, and the slow-down position is set after 320 degrees and before 330 degrees in the cam structure.

[0022] Preferably, an arc-shaped recessed structure is provided on the tensioning arm cam, and the arc-shaped recessed structure is located at the end of the tape-rewinding position area.

[0023] Compared with the prior art, a cam structure of a strapping machine core proposed in the present application adds an independent tape-rewinding area for performing the tape-rewinding action. When the core cam rotates to the tape-rewinding area, the right knife jacks up to press the leading end of the packing tape, and the tensioning arm cam does not press down the tensioning arm. At this time, the binding wheel is not pressed tightly. When the high-speed tape-rewinding is in place, the packing tape will slide on the tape feed and rewind wheel, thereby limiting the maximum binding force during tape-rewinding. By optimizing the original cam structure, the technical solution of the present invention well solves the problem of low efficiency when packing with a small binding force of the strapping machine core in the prior art without increasing the cost of the machine core. Brief Description of the Drawings

[0024] Figure 1 It is a three-dimensional structure schematic diagram of a cam structure of a strapping machine core of the present invention.

[0025] Figure 2 It is a schematic diagram for explaining the angular position of the cam structure of the present invention.

[0026] Figure 3 It is a schematic diagram of the structure of the cam structure of the present invention when it is in the zero position area.

[0027] Figure 4 It is a schematic diagram of the structure of the cam structure of the present invention when it is in the tape-rewinding area.

[0028] Figure 5 It is a schematic diagram of the structure of the cam structure of the present invention when it is in the binding area.

[0029] Figure 6 It is a schematic diagram of the recessed structure on the tensioning arm cam of the cam structure of the present invention.

[0030] Figure 7 It is a schematic diagram of the structure of the cam structure of the present invention at the slow descent position of the slide cam. Detailed Embodiments

[0031] Next, in combination with the drawings and specific embodiments, a cam structure of a strapping machine core of the present invention will be further described to facilitate a clearer understanding of the technical idea claimed by the present invention.

[0032] As Figure 1 shown, the cam structure of the strapping machine core includes a right knife cam 11, a slide cam 12, a middle knife cam 13, a heating head cam 14, a left knife cam 15, and a tensioning arm cam 16.

[0033] Figure 2Schematic diagram for the angular position description of the cam structure described in this document. In this document, when the cam structure is at the center position of the zero position area, it is defined as 0 degrees of the cam structure. As Figure 2 shown, in the rotation direction of the cam structure, it successively passes through the zero position area 21, tape retraction area 22, bundling area 23, heat-sealing area 24, cooling area 25, slide plate opening area 26, and slide plate reset area 27.

[0034] It should be noted that Figure 2 the angular positions of the areas described in are based on the overall cam structure. Since the positions of the push rods corresponding to the slide plate cam 12, the ironing head cam 14, and the tension arm cam 16 are not at the top 0-degree position shown in the figure, the 0-degree position needs to be rotated to the position of the corresponding push rod for these two cams to obtain the angular position diagrams of the corresponding cams.

[0035] The zero position area 21, tape retraction area 22, and bundling area 23 are designed to have a certain width, which can reduce the requirements for the positioning accuracy of the camshaft. The cooling area 25 is designed to have a larger width, enabling the bundling machine core to achieve a basic cooling time without turning off the main shaft motor during the packing process. Thus, the working speed of the bundling machine core is improved.

[0036] The described zero position area 21 occupies the range of -4 degrees to 4 degrees in the cam structure, and the angular range is 8 degrees. Figure 3 shows the state of the cam structure of the bundling machine core when it is in the zero position area 21. When the machine core is in the zero position area, all components are in the reset state. At this time, the right knife cam 11, the middle knife cam 13, and the left knife cam 15 are all at the low points, and the right knife 31, the middle knife 33, and the left knife 35 are all in the lowered state. The slide plate cam 12 and the tension arm cam 16 are also at the low points, and the slide plate push rod 32 and the tension arm 36 are in the reset state. The ironing head cam 14 is at the high point, the ironing head push rod 34 is pushed open, and the ironing head is in the disengaged state.

[0037] The described tape retraction area 22 occupies the range of 16 degrees to 30 degrees in the cam structure, and the angular range is 14 degrees. Figure 4 shows the state of the machine core when the cam structure rotates to the tape retraction area 22. At this time, the right knife cam 11 rises, pushing the right knife 31 up to press against the packing tape head. The tension arm cam 16 continues to be at the low point, and the tension arm cam 36 is in the reset state, not exerting a pressing force on the packing tape.

[0038] The described bundling area 23 occupies the range of 56 degrees to 70 degrees in the cam structure, and the angular range is 14 degrees. Figure 5 shows the state of the machine core when the cam assembly rotates to the bundling area 23. At this time, the right knife cam 11 rotates to the highest point, pushing the right knife 31 up to the highest position to generate the maximum pressing force. At the same time, the tension arm cam 16 also rotates to the high point, pressing down the tension arm 36 to apply sufficient pressing force to the packing tape.

[0039] From the above data, it can be calculated that in this embodiment, the minimum angle difference between the tightening area 23 and the unwinding area 22 is 26 degrees, and the maximum angle difference is 54 degrees.

[0040] In order to enable the right knife to be lifted to a sufficient height when unwinding the strap, the right knife cam 11 needs to be a certain distance higher than the zero position area 21 in the unwinding area 22. When the cam structure is in the unwinding area 22 and the tightening area 23, the right knife 31 needs to keep pressing the strapping head, and the pressing force in the tightening area should not be less than that in the unwinding area. Therefore, the radius of the right knife cam 11 in the tightening area 23 should not be less than that in the unwinding area 22.

[0041] In order to ensure that strapping tapes of different thicknesses can be reliably pressed, the right knife 31, the middle knife 33 and the left knife 35 in the strapping machine core are all designed as compressible elastic structures. The lifting process of the right knife 31 from the withdrawal zone to the tightening zone is achieved by compressing the spring in the right knife, which also increases the pressing force on the strapping tape. Excessive compression stroke will cause the rotational resistance of the cam group to become very large, so the compression stroke is not the larger the better. The height difference in these two areas needs to be controlled within 2mm. Splitting the right knife lifting process into two stages from the zero position zone to the withdrawal zone and from the withdrawal zone to the tightening zone is conducive to reducing the rotational resistance of the cam group. In this embodiment, the radius R21 of the right knife cam in the zero position zone 21 is 28mm, the radius R22 in the withdrawal zone 22 is 31mm, and the radius R23 in the tightening zone 23 is 32mm. In this way, the radius difference between the right knife cam 11 in the withdrawal zone 22 and the zero position zone 21 is 3mm, and the radius difference between the tightening zone 23 and the withdrawal zone 22 is 1mm. The radius R24 of the tension arm cam 16 at the unwinding area 22 is 15 mm, and the radius R25 at the tightening area 23 is 25 mm, and the difference between the two is 10 mm.

[0042] like Figure 6 As shown, in order to make the cam structure in the entire belt withdrawal area 22, the tensioning arm 36 is in the reset state, and an arc-shaped recessed structure 161 is provided on the tensioning arm cam 16 at the end of the belt withdrawal area 22. The addition of the arc-shaped recessed structure 161 can make the tightening arm cam 16 use a larger pressure angle in the front section with smaller resistance, and use a smaller pressure angle after the resistance increases, so that the cam rotation process can be smoother.

[0043] The hot-joining area 24 occupies the interval of 88 degrees to 162 degrees in the cam structure, and the angle range is 74 degrees. The hot-joining action is to briefly insert the hot-joining head into the middle of the two layers of strapping tape and quickly detach it. After the hot-joining head is inserted into the middle of the strapping tape, the middle knife 33 pushes up and presses the two layers of strapping tape onto the hot-joining head to melt the surface of the strapping tape.

[0044] The cooling zone 25 occupies the range of 182 degrees to 270 degrees in the cam structure, with an angular range of 88 degrees. The function of the cooling zone is to press the two layers of already molten packing belts together after the iron head detaches, and wait for a period of time for the temperature to decrease and the material to solidify. In this way, the welding of the packing belt is completed.

[0045] The skateboard opening zone 26 occupies the range of 288 degrees to 304 degrees in the cam structure, with an angular range of 16 degrees. The opening of the skateboard allows the packing belt to detach from the movement structure.

[0046] The three processes of ironing, cooling, and skateboard opening described in this embodiment are the same as those in the prior art, and will not be elaborated here.

[0047] The skateboard reset zone 27 occupies the range of 304 degrees to 356 degrees in the cam structure, with an angular range of 52 degrees. The skateboard is installed on the skateboard frame and can slide back and forth on the skateboard frame (the skateboard and the skateboard frame are not shown in the figure). The skateboard is pushed out of the skateboard frame by the skateboard push rod 32 to achieve the opening of the skateboard. A spring is provided between the skateboard and the skateboard frame. When the skateboard cam 12 rotates from the high point to the low point, the skateboard push rod 32 will return accordingly. The skateboard loses the support of the skateboard push rod 32 and then slides into the skateboard frame under the action of the spring to return to its position.

[0048] In the prior art, no corresponding treatment was done when the skateboard cam 12 was resetting the skateboard. This causes the skateboard to hit the skateboard seat at a relatively high speed during the return process. This method not only generates a large amount of noise, but also the large impact force is likely to cause damage to the structural components.

[0049] In this application, a slow-down position 121 is added to the skateboard cam 12, as Figure 7 shown. During the process of skateboard reset, when the skateboard is close to hitting the skateboard seat, the slow-down position 121 is used to reduce the speed of the skateboard push rod 32 and then continue to return. In this way, the impact force of the skateboard on the skateboard seat is much smaller. In order to achieve the speed reduction of the skateboard push rod 32 at the middle position, it is necessary to make the angle between the tangent of the skateboard cam 12 at the slow-down position 121 and the tangent of the concentric circle passing through this slow-down position of the camshaft as small as possible. Through experiments, it is found that it is optimal to be less than 10 degrees. In this way, the speed of the skateboard push rod at this position can be reduced to a relatively low level. In this embodiment, the angle between the two tangents is taken as 0 degree, that is, the tangent 712 of the skateboard cam 12 at the slow-down position 121 is also tangent to the concentric circle 711 of the camshaft passing through this slow-down position. In this way, the speed of the skateboard push rod 32 near the slow-down position 161 will be reduced to 0 and stay briefly before continuing to move inward.

[0050] Meanwhile, in order to achieve the purpose of decelerating in advance, the distance between the edge of the descent position cam and the central axis needs to be between 27 mm and 29 mm. If it is too small, the skateboard will hit the skateboard frame before reaching the descent position . If it is too large, the speed at which it hits the skateboard frame after the pause is still relatively high. In this embodiment, the distance between the edge of the skateboard cam 12 and the center line of the camshaft at the descent position is 27.5 mm, that is, the radius of the concentric circle 711 of the camshaft passing through the cam descent position is 27.5 mm. The descent position is set at the 325-degree position in the cam structure, that is, the position where the skateboard cam 12 rotates 325 degrees following the cam structure from the 0-degree position.

[0051] For those skilled in the art, various corresponding changes and deformations can be made according to the technical solutions and concepts described above, and all these changes and deformations should fall within the protection scope of the claims of the present utility model.

Claims

1. A cam structure of a strapping machine core, characterized in that, Including: Right knife cam, slide plate cam, middle knife cam, iron head cam, left knife cam and tension arm cam; The cam structure successively includes a zero position area, a tape retracting area, a bundling area, a welding area, a cooling area, a slide plate opening area and a slide plate reset area; The radius of the right knife cam in the tape retracting area is greater than that in the zero position area, and the radius difference between the two is not less than 2 mm; The radius of the tension arm cam in the tape retracting area is less than that in the bundling area, and the radius difference between the two is not less than 6 mm; The angular difference between the tape retracting area and the bundling area is not less than 18 degrees and not greater than 72 degrees.

2. A cam structure of a strapping machine core according to claim 1, characterized in that The angular range of the zero position area is not less than 4 degrees and not greater than 15 degrees; The angular range of the tape retracting area is not less than 4 degrees and not greater than 36 degrees; The angular range of the bundling area is not less than 4 degrees and not greater than 36 degrees; The angular range of the welding area is not less than 60 degrees and not greater than 120 degrees; The angular range of the cooling area is not less than 72 degrees and not greater than 144 degrees; The angular range of the slide plate opening area is not less than 10 degrees and not greater than 30 degrees; The angular range of the slide plate reset area is not less than 45 degrees and not greater than 60 degrees.

3. A cam structure of a strapping machine core according to claim 2, characterized in that The minimum angular difference between the tape retracting area and the bundling area is 24 degrees, and the maximum angular difference is 56 degrees.

4. A cam structure of a strapping machine core according to claim 2, characterized in that The radius difference between the right knife cam in the tape retracting area and the zero position area is not less than 2 mm and not greater than 5 mm, the radius in the bundling area is greater than or equal to that in the tape retracting area, and the radius difference between the two is not greater than 2 mm; The radius difference between the tension arm cam in the tape retracting area and the bundling area is not less than 6 mm and not greater than 14 mm.

5. A cam structure of a strapping machine core according to claim 2, characterized in that The zero position area occupies the interval of -4 degrees to 4 degrees in the cam structure; The tape retracting area occupies the interval of 16 degrees to 30 degrees in the cam structure; The bundling area occupies the interval of 56 degrees to 70 degrees in the cam structure; The welding area occupies the interval of 88 degrees to 162 degrees in the cam structure; The cooling area occupies the interval of 182 degrees to 270 degrees in the cam structure; The slide plate opening area occupies the interval of 288 degrees to 304 degrees in the cam structure; The slide plate reset area occupies the interval of 304 degrees to 356 degrees in the cam structure.

6. A cam structure of a strapping machine core according to claim 4, characterized in that, The radius of the right knife cam in the zero position area is 28 mm ± 1 mm; the radius in the tape retracting area is 31 mm ± 1 mm; the radius in the bundling area is 32 mm ± 1 mm; the radius of the tension arm cam in the tape retracting area is 15 mm ± 1 mm, and the radius in the bundling area is 25 mm ± 1 mm.

7. A cam structure of a strapping machine core according to claim 1, characterized in that, The slide plate cam is provided with a slow descent position in the slide plate reset area, and the angular difference between the tangent line of the cam at the slow descent position and the tangent line direction of the concentric circle of the cam central axis at the slow descent position is not greater than 10 degrees.

8. A cam structure of a strapping machine core according to claim 7, characterized in that, The tangent line of the slide plate cam at the slow descent position is tangent to the concentric circle passing through the slow descent position of the cam shaft.

9. The cam structure of a strapping machine core according to claim 8, characterized in that The distance between the edge of the slow-down position cam and the center line of the camshaft is 27 mm to 29 mm. The slow-down position is set after 320 degrees and before 330 degrees in the cam structure.

10. A cam structure of a strapping machine core according to claim 1, characterized in that, The tensioning arm cam is provided with an arc-shaped recessed structure, and the arc-shaped recessed structure is located at the end of the tape-rewinding position area.

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