JP3634993B2 - Film feeding unit - Google Patents

Description

[0001]
[Field of the Invention]
The present invention relates to a film supply unit applied to a film packaging machine for packaging industrial products and the like with a film.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a film wrapping machine that wraps a film around an industrial product or a packaging box that packs these products has been provided. Such a film packaging machine generally includes an apparatus main body having a turntable and a film supply unit provided on the apparatus main body.
[0003]
FIG. 5 is a schematic view showing a packaging operation by a conventional general film packaging machine. Referring to FIG. 1, reference numeral 1 indicates a film supply unit. An object (industrial product or the like) 2 to be packaged is rotated on a turntable (not shown) and the film 3 is fed out from the film supply unit 1 in the direction of arrow 4. Thereby, the object 2 is wrapped around the film 3 around the object 2.
[0004]
By the way, the film 3 is fed as follows. That is, the film 3 is wound in advance to form a film roll 5 and stocked. Then, the film 3 fed out from the film roll 5 is sequentially placed on the rollers 6, 7, 8, 9 and supplied to the object 2. At this time, in order to satisfactorily wind the film 3 around the object 2, it is necessary to apply a predetermined tension to the supplied film 3, and it is desirable to keep this tension constant.
[0005]
In order to adjust the tension of the film 3, a mechanism as shown in FIG. 6 has been proposed. Referring to the drawing, this tension adjusting mechanism is for adjusting the tension of film 3 and includes a tension arm 10, a spring 11, and limit switches 12 and 13. One end portion 14 of the tension arm 10 rotatably supports a rotating shaft 15 of the roller 9, and the other end portion 16 is rotatably supported at a predetermined position of the film supply unit 1 via a shaft 17. ing. The spring 11 is interposed between the tension arm 10 and a predetermined portion of the film supply unit 1, and elastically biases the tension arm 10 in the direction of the arrow 18 in the figure. That is, the spring 11 applies a certain tension to the film 3 in a steady state.
[0006]
Here, when the tension applied to the supplied film 3 becomes small, the tension arm 10 rotates in the direction of the arrow 18 and the limit switch 12 enters the input state. On the other hand, when the tension applied to the supplied film 3 becomes large, the tension arm 10 rotates in the direction of the arrow 19 and the limit switch 13 enters the input state. Then, by inputting these limit switches, the speed of the film 3 fed out from the film roll 5 is adjusted, and thereby the tension of the supplied film 3 is adjusted.
[0007]
[Problems to be solved by the invention]
In such a conventional tension adjusting mechanism, since the tension of the supplied film 3 is monitored by the limit switches 12 and 13, the tension is not always monitored, and the tension is small or large with respect to a certain tension. This is detected when the is added. Therefore, the tension of the film 3 could not be kept constant. Of course, the number of limit switches can be increased to closely monitor the variation in tension, but this complicates the tension adjustment mechanism and increases the cost.
[0008]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a film supply unit that can maintain a constant tension of a supplied film and realize better film packaging for an object.
[0009]
[Means for Solving the Problems]
(1) In order to achieve the above object, the invention according to the present application is a film supply unit that is applied to a film packaging machine that winds a film around an object, and that supplies a film with a predetermined tension applied thereto, A film roll holding part that stocks a film roll in which a long film is wound in advance in a state where the film roll can be fed, and a film that is rotated around the axial direction and a film fed from the film roll comes into contact with the outer peripheral surface part. One roller, a second roller that rotates around the axial direction so as to have a peripheral speed faster than the peripheral speed of the first roller, and the film that has passed through the first roller comes into contact with the outer peripheral surface portion, and an axial direction A swing roller that can rotate freely, and the film that has passed through the second roller is in contact with the outer peripheral surface portion and can move in the contact direction and the anti-contact direction; -A tension arm that can support the shaft of the roller in a cantilevered manner and can be elastically deformed to allow the swing roller to move in the above-mentioned direction, and a strain sensor that is attached to the tension arm and constantly detects strain of the tension arm And The tension arm has a roller support portion that supports the shaft of the swing roller, and a sensor mounting portion having a smaller section coefficient than the roller support portion, and the strain sensor includes the sensor mounting portion. Consisting of a strain gauge attached to It is characterized by this.
[0010]
According to this configuration, the film fed from the film roller is hung on the first roller and the second roller. At this time, since the second roller is rotated at a faster peripheral speed than the first roller, the film is stretched when passing through the first roller and the second roller, and a predetermined tension is applied in advance. The The film to which the tension is applied in this manner is supplied to the object side in contact with the swing roller. At this time, the swing roller is supported by a tension arm, and when the tension applied to the film fluctuates, the swing roller moves in the contact direction or the anti-contact direction of the film. As a result, the tension arm is bent and elastically deformed, resulting in distortion. By detecting and monitoring this strain with a strain sensor, the tension to be always applied to the film can be kept constant.
[0012]
Also, In addition to the above operation, since the strain gauge is used as the strain sensor, the strain sensor can be configured at low cost. In addition, since the strain gauge is attached to a portion having a smaller section modulus than that of the roller support portion, it is possible to accurately measure strain.
[0013]
(2) Further, in the invention according to the present application, the sensor mounting portion includes a tension surface that receives a tensile force when the tension arm swings due to the movement of the swing roller, and a compression surface that receives a compression force. The gauge is attached to the tension surface and the compression surface, respectively.
[0014]
According to this configuration, in addition to the above-described operation, the strain of the tension arm is detected for both the tension surface and the compression surface, so that the strain generated in the tension arm can be detected and monitored with higher accuracy.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below.
[0016]
FIG. 1 is an external perspective view of a film packaging machine provided with a film feeding unit according to an embodiment of the present invention.
[0017]
This will be described with reference to FIG. The film packaging machine 20 includes a main body 21 and a film feeding unit 22 provided on the main body 21.
[0018]
The main body 21 has an L-shaped support frame 23 that supports the film feeding unit 22, and a turntable 24 provided at the tip of the support frame 23.
[0019]
The support frame 23 has a slide rail 25 to which the film feeding unit 22 is attached. Thereby, the film feeding unit 22 can slide up and down along the slide rail 25. The slide of the film feeding unit 22 is not shown, but can be achieved by adopting a known slide mechanism such as a ball screw mechanism, a chain / sprocket mechanism, or the like. Reference numeral 26 indicates a control device for sliding the film feeding unit 22, and the control device 26 causes the film feeding unit 22 to match the height of the packaging object 27 (industrial product, etc.). The height position is adjusted accordingly.
[0020]
The turntable 24 is for placing the packaging object 27 and rotating it. The turntable 24 is supported by a drive shaft of a motor (not shown) provided on the support frame 23, and the packaging object is rotated on the turntable 24 by operating the motor. .
[0021]
On the other hand, the film feeding unit 22 supplies the film 28 to the packaging object 27. The film feeding unit 22 according to the present embodiment feeds the film 28 in a state where the film 28 is stretched in advance and a predetermined tension is applied.
[0022]
Therefore, by feeding the film 28 while turning the turntable 24, the film 28 to which tension has been applied in advance is wound around the packaging object 27. As a result, it is possible to prevent a large external force from acting on the packaging object 27 in the operation of winding the film 28, and after winding the film 28, the packaging object 27 is firmly attached with the tension force applied in advance. It can be packaged.
[0023]
The feature of this embodiment is the structure of the film feeding unit 22 described above, and the tension of the film 28 fed to the packaging object 27 is always kept constant to realize better film packaging. There is a point that can be done. Hereinafter, the structure of the film feeding unit 22 will be described in detail.
[0024]
2 is a main part front view of the film feeding unit 22, FIG. 3 is a main part plan view, and FIG. 4 is a main part right side view.
[0025]
First, a schematic configuration of the film feeding unit 22 will be described with reference to FIG. The film feeding unit 22 includes a casing 42, a film roll holding unit 30 for stocking the film 28 in advance, a first roller 31 and a second roller 32 for applying a predetermined tension to the film 28 in advance. A drive mechanism 37 for rotationally driving the first roller 31 and the second roller 32, and a tension adjusting unit 33 for adjusting the tension of the film 28 fed to the packaging object 27 (see FIG. 1). And idle rollers 34, 35, and 36 for winding the film 28.
[0026]
(1) Casing
This will be described with reference to FIGS. The casing 42 can be made of, for example, a steel plate. The casing 42 has a roller accommodating portion 50 and a head portion 51. The roller accommodating portion 50 accommodates the first roller 31, the second roller 32, the tension adjusting portion 33, and the idle rollers 34, 35, and 36. The head portion 51 is provided above the roller accommodating portion 50 and accommodates the drive mechanism 37. The casing 42 is provided with reinforcing members 52 and 53 for reinforcement.
[0027]
(2) Film roll holder
The film roll holding unit 30 stocks the long film 28 in advance in order to continuously feed the film 28, and can sequentially feed the film 28 as necessary. The long film 28 is previously wound and formed as a film roll 49 (see FIG. 3).
[0028]
The film roll holding unit 30 is provided on the outside of the casing 42, and includes an upper support member 38, a lower support member 39, and holding members 40 and 41 provided on these members, respectively.
[0029]
The upper support member 38 is fixed to the side wall 44 of the casing 42 via the bracket 43. As this fixing structure, as shown in the figure, a fastening structure with bolts 45 and nuts 46 can be adopted. Further, the lower support member 39 is fixed below the side wall 44 of the casing 42 so as to face the upper support member 38. In the present embodiment, the upper support member 38 is a member having a large thickness and the lower support member 39 is a member having a small thickness. However, this is a problem in design, and these are constituted by the same member. You can also.
[0030]
The holding member 40 can be made of, for example, a synthetic resin. The holding member 40 has a bottom plate portion 47 and a cylindrical portion 48 formed continuously therewith. The cylindrical portion 48 is inserted into the center portion of the film roll 49. Therefore, the film roll 49 is sandwiched and held by the pair of holding members 40 and 41 in the vertical direction. In order to ensure this holding without shakiness, the cylindrical portion 48 is slightly Is formed into a so-called tapered shape. Then, as shown in FIG. 3, by pulling the film 28 in the circumferential direction of the film roll 49, the film roll 49 rotates and the film 28 is fed out sequentially.
[0031]
The holding members 40 and 41 are fastened to the upper support member 38 and the lower support member 39 by bolts 54 and nuts 55, respectively. Further, in order to smoothly draw out the film 28 from the held film roll 49, it is possible to adopt a structure in which the holding members 40 and 41 are rotatable around the bolt 54.
[0032]
(3) First roll / second roll
The first roll 31 has a rotating shaft 56 and a roller body 57. The roller body 57 is fixed to the rotating shaft 56. The roller body 57 is wound around the outer peripheral surface of which the film 28 is abutted. In order to prevent slippage between the roller body 57 and the film 28, the roller body 57 is made of resin or the like. It can also be configured. In FIG. 3, reference numeral 58 indicates a key, and the rotary shaft 56 is connected to a drive mechanism 37 described in detail later by the key 58.
[0033]
Further, the second roller 32 has a rotation shaft 59 and a roller body 60. The roller body 60 is fixed to a rotation shaft 59, and the rotation shaft 59 is connected to the drive mechanism 37 by a key 61. In the present embodiment, the first roller 31 and the second roller 32 have the same configuration. However, the first roller 31 and the second roller 32 do not need to have the same configuration, and it is needless to say that the design can be changed as necessary.
[0034]
(4) Drive mechanism
The drive mechanism 37 is for rotating and driving the first roller 31 and the second roller 32 described above. A drive motor 69 (see FIG. 4) and a drive shaft 62 (see FIG. 3) of the drive motor 69 are provided. A small-diameter pulley 63 attached, a large-diameter pulley 64 attached to the second roller 32, a belt 67 connecting the small-diameter pulley 63 and the large-diameter pulley 64, and a small-diameter sprocket 65 attached to the second roller 32 And a large-diameter sprocket 66 attached to the first roller 31, and a small-diameter sprocket 65 and a chain 68 that connects the large-diameter sprocket 66. In FIG. 2, the drive shaft 62 and the small-diameter pulley 63 of the drive motor 69 are not shown.
[0035]
According to this drive mechanism 37, when the drive motor 69 is driven and the drive shaft 62 rotates, the large-diameter pulley 64 is rotated via the belt 67, and the second roller 32 is rotated. When the second roller 32 rotates, the large-diameter sprocket 66 is rotated via the chain 68, and the first roller 31 rotates.
[0036]
Here, in this embodiment, the effective diameter of the small diameter sprocket 65 is set to one third of the effective diameter of the large diameter sprocket 66. Accordingly, the second roller 32 is rotated at a speed three times that of the first roller 31. Since the roller body 57 of the first roller 31 and the roller body 60 of the second roller 32 have the same outer diameter, the film 28 to be fed passes through the first roller 31 and the second roller 32. And a predetermined tension is applied.
[0037]
In addition, in order to make the rotational speed of the 1st roller 31 and the 2nd roller 32 differ, in this embodiment, although the structure which attaches the sprockets 65 and 66 of a different diameter to each roller 31 and 32 was employ | adopted, each roller main body The outer diameters of 57 and 60 may be different.
[0038]
(5) Idle roller
The idle rollers 34, 35, and 36 all have the same configuration. The idle roller 36 is not shown in FIG. 2 in order to illustrate the tension adjusting unit 33 in detail.
[0039]
Each idle roller 34, 35, 36 has a rotation shaft 70 and a roller body 71. The upper and lower ends of each rotating shaft 70 are fixed to the casing 42, and each roller body 71 is rotatable with respect to the rotating shaft 70. The fixing to the casing 42 can be achieved, for example, by fastening the rotating shaft 70 with a bolt 82.
[0040]
(6) Tension adjustment part
With reference to FIGS. 3 and 4, the tension adjusting unit 33 includes a tension arm 72, a swing roller 73, and a strain sensor 74.
[0041]
In this embodiment, the tension arm 72 is composed of a plate member having a predetermined thickness, and the base end portion 75 is fixed to the casing 42. This fixing is achieved by fastening with a bolt 76, for example.
[0042]
The tip end portion of the tension arm 72 is configured as a roller support portion 77 for supporting the swing roller 73, and an attachment hole 78 for mounting the swing roller 73 is provided. The tension arm 72 is formed with a sensor attachment portion 79 at an intermediate portion between the roller support portion 77 and the base end portion 75. The sensor mounting portion 79 is configured by reducing the dimension in the width direction of the tension arm 72.
[0043]
That is, the sensor mounting portion 79 is set so that its section modulus is smaller than that of the roller support portion 77 and the base end portion 75. Therefore, the shape of the sensor mounting portion 79 does not have to be reduced in width as shown in the present embodiment. In short, the section modulus is larger than that of other portions (the roller support portion 77 and the base end portion 75). Any other shape may be used if it is small.
[0044]
As shown in FIGS. 2 and 4, in the present embodiment, a pair of tension arms 72 are provided vertically. That is, the upper and lower ends of the swing roller 73 are supported by the pair of tension arms 72.
[0045]
The effect of providing a pair of sensor mounting portion 79 and tension arm 72 having a reduced section modulus in this way will be described later.
[0046]
The swing roller 73 has a rotation shaft 80 and a roller body 81. The roller body 81 is rotatable about the rotation shaft 80. The upper and lower ends of the rotating shaft 80 are supported by the roller support portion 77 of the tension arm 72, and specifically, the rotating shaft 80 is fitted in the mounting hole 78 of the roller support portion 77.
[0047]
The strain sensor 74 employs a strain gauge in this embodiment. However, the strain sensor 74 is not limited to a strain gauge, and other known strain sensors can be employed. The strain sensor 74 is connected to a control device (not shown). The control device receives a strain signal from the strain sensor 74 and controls the rotation of the motor of the drive mechanism 37 based on the strain signal. It has become. That is, when an excessive tension is applied to the film 28, the rotational speed of the motor is increased so as to decrease the tension of the film 28. On the other hand, when the tension of the film 28 is excessively decreased, the motor rotates. It works to ensure a predetermined tension by reducing the speed.
[0048]
In the present embodiment, the strain sensor 74 is attached to both sides of the sensor attachment portion 79 of the tension arm 72 as shown in the drawing. That is, the strain sensor 74 is attached to a surface that receives a tensile stress (tensile surface) and a surface that receives a compressive stress (compressed surface) when the tension arm 72 is bent.
[0049]
(7) How to use and effect of film packaging machine
Next, the film packaging operation by the film packaging machine 20 provided with the film feeding unit 22 according to this embodiment will be described together with the function and effect of the film feeding unit 22.
[0050]
First, referring to FIG. 3, the film roll 49 is supported by the film roll holding unit 30, and the long film 28 is stocked in advance. The film 28 is pulled out from the film roll 49, and this is drawn into the idle roller 34, the roller main body 57 of the first roller 31, the idle roller 35, the roller main body 60 of the second roller 32, the swing roller 73 of the tension adjusting unit 33, and the idle roller. Multiply around 36. As a result, the film 28 abuts along the outer peripheral surface of the idle roller 34, the roller body 57, the idle roller 35, the roller body 60, the roller body 81 of the swing roller 73, and the idle roller 36. At this time, as described above, the film 28 is stretched by the first roller 31 and the second roller 32, and a predetermined tension is applied.
[0051]
In this state, the film 28 is wound around the packaging object 27 as shown in FIG. This operation is performed while rotating the turntable 24 while feeding the film 28 from the film feeding unit 22.
[0052]
During the winding operation of the film 28, the tension applied to the supplied film 28 may fluctuate due to, for example, the shape of the packaging object 27 and other reasons. At this time, the swing roller 73 is supported by the tension arm 72. Therefore, when the tension applied to the film 28 fluctuates, the swing roller 73 moves in the contact direction or the anti-contact direction of the film 28. As a result, the tension arm 72 undergoes bending and elastically deforms, causing distortion. By monitoring and detecting this distortion with the strain sensor 74, the tension to be always applied to the film 28 can be kept constant.
[0053]
Therefore, according to the film feeding unit 22 according to the present embodiment, distortion generated in the tension arm 72 can always be detected in real time, so that the film that is in contact with the swing roller 73 supported by the tension arm 72. The tension of the film 28 (that is, the film supplied to the object) can be constantly monitored, and the amount of the film 28 fed out from the film roll 49 can be constantly adjusted. Thereby, the tension of the supplied film 28 can always be kept constant, and the film packaging of the packaging object 27 can be made better than before.
[0054]
In particular, in this embodiment, since the strain of the tension arm 72 is always monitored electrically, the tension of the supplied film 28 can be kept constant, and the tension of the film 28 can be changed as necessary. Can be adjusted. As a result, the following specific effects can be obtained.
[0055]
That is, for example, when the packaging object 27 is a stacked cardboard box or the like, if the film 28 is always supplied with a constant tension, the lower part of the packaging object 27 may be displaced due to the weight of the packaging object 27 itself. The film 28 can be wound well, but when the film 28 is wound above the packaging object with the same tension as that wrapped around the packaging object 27, the packaging object 27 collapses due to the tension of the film 28. May be caused. However, in this embodiment, since the tension of the supplied film 28 can be adjusted, the lower part of the packaging object 27 can be wound with a strong tension, and the upper part can be wound with a weak tension. Thereby, even if it is a case where it is the corrugated cardboard box etc. with which the packaging target object 27 was piled up, a film packaging can be performed favorably, without raise | generating a load collapse.
[0056]
Moreover, in this embodiment, since a strain gauge is used as the strain sensor 74, there is an advantage that the strain sensor 74 can be configured at low cost.
[0057]
In addition, since the strain gauge is attached to the sensor attachment portion 79 having a smaller section modulus than that of the roller support portion 77, the strain can be measured with high accuracy. As a result, the tension of the film 28 can be accurately monitored, and a better film packaging operation can be performed.
[0058]
In addition, in this embodiment, the strain sensor 74 is attached to both the tension surface and the compression surface of the tension arm 72, and the strain generated in the tension arm 72 is detected by two sensors. ing. Therefore, the distortion generated in the tension arm 72 can be detected and monitored with higher accuracy. As a result, the strain of the tension arm 72 can be monitored more accurately, and an even better film packaging operation can be performed.
[0059]
In particular, in this embodiment, since the tension arms 72 to which the strain sensors 74 are attached are provided at the upper and lower ends of the swing roller 73, the tension of the film 28 is monitored by the four strain sensors 74. Therefore, the tension of the film 28 can be adjusted with extremely high accuracy.
[0060]
【The invention's effect】
As described above, according to the invention according to the present application, distortion generated in the tension arm can be detected in real time at all times, so that the film in contact with the swing roller supported by the tension arm (that is, supplied to the object) The tension of the film) can always be monitored. Thereby, it is possible to always adjust the amount of the film fed from the film roller continuously, and as a result, the tension of the supplied film can always be kept constant. As a result, the film packaging of the object can be made better than before (the invention according to claim 1).
[0061]
In particular, in the present invention, since a strain gauge is used as the strain sensor, there is an advantage that the strain sensor can be configured at low cost and the manufacturing cost of the film supply unit can be reduced (invention according to claim 2).
[0062]
Furthermore, in the present invention, the strain of the tension arm can be detected for both the tension surface and the compression surface, and the strain generated in the tension arm can be accurately detected and monitored. Can keep. As a result, the film packaging of the object can be further improved (the invention according to claim 3).
[Brief description of the drawings]
FIG. 1 is an external perspective view of a film packaging machine provided with a film feeding unit according to an embodiment of the present invention.
FIG. 2 is a main part front view of a film feeding unit according to an embodiment of the present invention.
FIG. 3 is a plan view of a main part of a film feeding unit according to an embodiment of the present invention.
FIG. 4 is a right side view of an essential part of a film feeding unit according to an embodiment of the present invention.
FIG. 5 is a schematic view showing a packaging operation by a conventional general film packaging machine.
FIG. 6 is a schematic diagram showing a configuration of a conventional general tension adjusting mechanism.
[Explanation of symbols]
20 Film packaging machine
22 Film feeding unit
27 Packaging objects
30 Film roll holder
31 First roller
32 Second roller
33 Tension adjuster
37 Drive mechanism
49 Film roll
56 Rotating shaft
57 Roller body
59 Rotating shaft
60 Roller body
72 Tension arm
73 Swing roller
74 Strain sensor
75 Base end
77 Roller support
79 Sensor mounting part
80 axis of rotation
81 Roller body

Claims (2)

A film supply unit that is applied to a film packaging machine that winds a film around an object and supplies a film with a predetermined tension applied thereto,
A film roll holding unit that stocks a film roll in which a long film is wound in advance in a state where the film roll can be drawn,
A first roller that is rotated around an axial direction and a film fed from a film roll is brought into contact with the outer peripheral surface portion;
A second roller that is rotated around the axial direction so as to have a peripheral speed faster than the peripheral speed of the first roller, and the film that has passed through the first roller is in contact with the outer peripheral surface portion;
An oscillating roller that is rotatable about an axial direction, and the film that has passed through the second roller is in contact with the outer peripheral surface portion and can move in the contact direction and the anti-contact direction;
A tension arm that supports the shaft of the swing roller in a cantilevered manner and can be elastically deformed to allow the swing roller to move in the above direction;
A strain sensor attached to the tension arm and constantly detecting strain of the tension arm ;
The tension arm includes a roller support portion that supports the shaft of the swing roller, and a sensor attachment portion that is set to have a smaller section coefficient than the roller support portion,
The film supply unit , wherein the strain sensor comprises a strain gauge attached to the sensor attachment portion . The film supply unit according to claim 1 , wherein
The sensor mounting portion has a tension surface that receives a tensile force when the tension arm swings due to the movement of the swing roller, and a compression surface that receives a compression force,
The film supply unit, wherein the strain gauge is attached to each of the tension surface and the compression surface.

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