JPH1035605A - Film holding device in stretch film packaging machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent damage to articles and film and obtain a favorable packaged condition. SOLUTION: Respective film edges of the front and rear and the right and left directions are held between a film-drawing body 23 as a front holding member and a rear holding member 28 and between both right and left holding members 29. A supply film 21 covering the upper side of an article 26 in a preliminarily stretched condition is folded to the underside of the article 26 to package the article by film-folding members 5, 9, 14. After this preliminary stretching motion, a motion to reduce the preliminarily stretched length is executed and the holding forces of the film edges by respective holding members 23, 28, 29 are lessened in accordance with the reducing motion of the preliminarily stretched length.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stretch film wrapping machine for wrapping an article by folding a supply film covering the upper side of the article with the edge of the film sandwiched under the article, and BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for holding a film, and more particularly to a device capable of adjusting a film holding force and a film elongation.

[0002]

2. Description of the Related Art In a film clamping apparatus according to Japanese Patent Application No. 8-32319 filed on Feb. 20, 1996 by the present applicant, a pre-stretched film is required to have sufficient tension after being packed. The mechanism is adopted. In this pre-stretching mechanism, the tray on the receiving stand is raised, the interval between the opposing lateral sandwiching members is expanded, the supply film is extended, and the tray is pressed against the supply film in the extended state in the middle of the ascent. Has become. At the time of the film folding operation after the completion of the pre-stretching operation, the film holding force by each holding member is reduced, and the film edge is easily released from each holding member, thereby preventing the tray and the film from being damaged.

[0003]

However, even if the film holding force is reduced after the completion of the pre-stretching operation, the tray is pressed against the film while being raised, so that the resulting film tension acts as a reaction force on the tray. Works. In particular, trays with extremely poor strength are likely to be warped and deformed by the film tension. If the film folding operation is performed in this deformed state, even if the film holding force is reduced, if the tray is restored after packaging, the upper surface of the tray that is pressed against the film and warped will be Because of shrinkage, the film after packaging may have wrinkles on the upper surface of the tray due to loosening.

[0004] The present invention is an improvement of the film holding device,
Prevent damage to articles (tray) and film,
The purpose is to obtain good packaging.

[0005]

According to a first aspect of the present invention, there is provided a stretch film wrapping machine which draws a supply film to a wrapping portion while approaching or separating from a film supply portion, and a film for the supply film. A holding member that drives so as to be able to take a state where the edge is held and a state where the holding edge is released, and a pre-stretching unit that performs a pre-stretching operation that can stretch the supply film drawn into the packaging unit by the film drawer. Have. Then, the supply film covering the upper side of the article in a state of being pre-stretched while both film edges are sandwiched between the sandwiching members opposed to each other with the packaging portion therebetween is folded under the article by the film folding member, and Is to be packaged.

[0006] In addition to a pinching force varying means for changing the pinching force of the film edge by the pinching member, a preliminary elongation amount reducing means is provided. In this means for reducing the amount of preliminary elongation,
While the article is rising toward the pre-stretched supply film in the wrapping section, a pre-stretch amount reducing operation for bringing at least one of the opposing holding members closer to the other is performed. .

[0007] The invention of claim 2 adds the following configuration to the invention of claim 1. The holding force varying means has a drive source for driving the holding member, and a drive transmission means provided in a drive transmission system from the drive source to the holding member. The drive transmitting means can control the transmitted driving force by the drive control means when transmitting the driving force from the driving source to the holding member.

[0008] The invention of claim 3 adds the following configuration to the invention of claim 2. The drive transmission means can control the transmission drive force release timing and the transmission drive force switching timing by the drive control means when transmitting the drive force from the drive source side to the holding member side.

The invention of claim 4 is the invention of claim 2 or claim 3.
The following configuration is added to the invention of (1). The holding member includes a holding member that is opposed to each other in a film width direction orthogonal to a film drawing direction of the film drawer. The pre-stretching means performs a pre-stretching operation to relatively separate the opposed sandwiching members so that the supply film having both film edges sandwiched by the opposed sandwiching members can be stretched, and performs a space between the opposed sandwiching members. Can be adjusted. The pre-stretching amount reducing means performs a pre-stretching amount reducing operation of relatively bringing the opposing holding members closer to each other so as to reduce the amount of elongation of the supply film having both film edges held by the opposing holding members. To adjust the distance between the opposing holding members,
This pre-elongation amount decreasing operation is started during the ascent of the article substantially in contact with the supply film. Drive control means is provided for controlling the drive transmission means for the sandwiching members facing each other in the film width direction in response to the operation of reducing the amount of preliminary elongation.

[0010] The invention of claim 5 is the invention of claims 2 to 4.
The following configuration is added to the invention of any one of the claims. It has a film feed braking unit for braking the drawing of the supply film by the film drawer. The holding member is
A holding member provided on the film drawer, and a holding member facing the holding member in a film drawing direction by the film drawer are provided. The pre-stretching means is capable of pre-stretching the film by braking the drawing of the supply film by the film feed brake unit before the film drawer pulls out the supply film and stops the film with the distance from the film supply unit. Perform the operation. There is provided a drive control means for controlling the braking timing of the film feed braking unit with respect to the stopping timing of the film drawer.

[0011] The invention of claim 6 adds the following configuration to the invention of claim 5. The pre-stretching amount reducing means performs a pre-stretching amount reducing operation of bringing the film drawer closer to the film feeding section so as to reduce the stretching amount of the supply film having both film edges sandwiched by the opposing holding members. The pre-stretching amount reducing operation is started during the ascent of the article substantially in contact with the supply film. A drive control means is provided for controlling the drive transmission means in response to the preliminary extension amount reduction operation.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a stretch film packaging machine according to an embodiment of the present invention.

[Outline of Stretch Film Wrapping Machine Shown in FIGS. 1 and 2]
Let the film drawing direction Q intersecting horizontally be the front-rear direction, and of the two sides facing each other in the film drawing direction Q, the upstream side is the rear side and the downstream side is the front side. Further, a film width direction R that is horizontally orthogonal to the film drawing direction Q is defined as a left-right direction, and one of two opposite sides in the film width direction R is one on the left (lower side in FIG. 2) and the other is on the right ( (Upper side of FIG. 2).

In the packaging section S in the film folding device 1 shown in FIG.
Can move horizontally in the left-right direction.
Left and right folding members 5 are supported on the left and right movable plates 2 so as to be rotatable in a horizontal direction about a shaft 6 and extend forward. The left and right ends 9a of the rear folding member 9 are supported so as to be able to move in the front-rear direction along the rails 10 on the machine frame 3. A main motor 77 with a speed reducer described later (FIG. 10,
11), a lever (not shown) that reciprocates in the front-rear direction in conjunction with a cam (not shown) that is rotated by the cam (not shown) is connected to the left and right ends 9a. A long hole 11 is formed in the left and right movable plates 2 so as to extend in the front-rear direction, and a long hole 12a is formed in both left and right end portions 9a of the rear folding member 9 so as to extend in the left and right direction. 12 is engaged with the elongated holes 11 and 12a. Both ends of the link 13 are rotatably supported between the guide pin 12 and the left and right folding members 5. When the rear folding member 9 moves in the front-rear direction due to the reciprocating movement of the lever, both guide pins 12 move along the long holes 11 and the left and right folding members 5 open and close with each other via the link 13.
A front folding member 14 is provided between the left and right machine frames 3 in front of the rear folding member 9.
Is attached. Front folding member 14 adjacent to packaging section S
A heater 15 is provided in front of.

In FIG. 1, reference numeral 16a denotes the film folding device 1.
Presser plate 16b above the film folding device 1
Is an article carry-out member that reciprocates in the front-rear direction above and below the article pressing plate 16a. Reference numeral 17 denotes a film supply switching device (to be described in detail later), and reference numeral 18 denotes upper and lower film supply units provided in the film supply switching device 17. 1
Reference numerals 9 and 20 denote film take-up rolls installed above the article holding plate 16a.
Is pulled out by the upper and lower film supply portions 18 and is held at the film supply position P. Reference numeral 23 denotes a film drawer (to be described in detail later) which reciprocates in the front-rear direction on a horizontal plane at the same height as the film supply position P, and approaches or separates from any one of the film supply portions 18. The films 21 and 22 are drawn out to the packaging section S. Reference numeral 24 denotes an article transport conveyor installed below the film folding device 1, and reference numeral 25 denotes this article transport conveyor 2.
4 is an article receiving table that moves up and down between the packaging section S in the film folding apparatus 1 and the articles 26 (those containing items placed in trays) placed on the transport conveyor 24 are in the lowest state. The article is conveyed toward the article receiving table 25.

[Film holding device 27 shown in FIGS.
As shown in FIG. 1, this film holding device 27 includes a rear holding member 28 (see FIG. 5) installed below the rear folding member 9 and a left and right movable plate 2 attached to the left and right movable plates 2. 6 and 9 and a front holding member (see FIGS. 3 and 4) that also serves as the film drawer 23 installed below the front folding member 14. Further, the pinching force varying means according to claim 1 is
A main motor 77 (see FIGS. 10 and 11) as a drive source for driving the rear holding member 28, the left and right horizontal holding members 29, and the front holding member (the film drawer 23). A drive transmission system T (see FIGS. 10 to 13) to 23, 28, and 29 has a drive transmission unit 78.

(Partial configuration of the film drawer 23 as a front holding member shown in FIGS. 3 and 4 and a drive transmission system T for the same) A rotary shaft 30 is supported inside the left and right machine frames 3 and A sliding cylinder 31 is inserted into the moving shaft 30 so as to be movable in the axial direction and to be integrally rotatable. The left and right sliding cylinders 31 are rotatably fitted to left and right end portions 32a of a support plate 32 extending in the left and right direction. Below the support plate 32, a plate-shaped fixed holding portion 36 is formed. At the center of the support plate 32, a support cylinder 37 is provided.
The support cylinder 37 has a comb-shaped central movable holding portion 38 attached thereto. Similarly, a support shaft 39 inserted into the support cylinder 37 is rotatably supported by the support plate 32, and a support fixed to the left and right sides of the central movable holding portion 38 so as to be integrally rotatable with the support shaft 39. Cylinder 3
At 9a, a comb-shaped horizontally movable holding portion 40 is attached. The left and right horizontal movable holding portions 40 rotate together with the central movable holding portion 38 and the left and right horizontal movable holding portions 40.
, And can be opened and closed with respect to the lower side of the fixed holding portion 36.

Pulleys 41c are attached to the left and right ends of the rotating shafts 41a and 41b, which are installed on the front and rear sides inside the left and right machine frames 3, respectively, so as to be integrally rotatable.
A rotating belt 42 is stretched between the left and right pulleys 41c, 41c. The film drawer 2
The left and right rotating belts 42 are connected to left and right end portions 32a of the third support plate 32. And the front and rear rotating shafts 41
When the drive-side rotating shaft 41b of the a and 41b is rotated by a servo motor 126 (see FIG. 16) described later, and the left and right rotating belts 42 are also rotated, the film drawer 23 rotates through the sliding cylinder 31. The film 21 moves along the axis 30, approaches or separates from the film supply unit 18 as described above, and pulls out the films 21 and 22 to the packaging unit S.

Interlocking levers 43 and 44 are attached to the support cylinder 37 and one support cylinder 39a, respectively. A plurality of guide rollers 46 and 47 are supported on a mounting plate 45 attached to the support plate 32, and an interlocking wire 48 is provided between the interlocking lever 43 interlocked with the central movable holding portion 38 and one of the sliding cylinders 31. An interlocking wire 49 is interposed between the interlocking lever 44 and the other sliding cylinder 31 interlocking with the left and right laterally movable holding portions 40 while being connected via the both guide rollers 46 via the both guide rollers 47. Are linked. Interlocking levers 50 and 51 are attached to the left and right rotating shafts 30, respectively. One ends 52a and 53a of interlock wires 52 and 53 are connected to the interlock levers 50 and 51, respectively. By the leaf springs 54 and the tension coil springs 55 for urging the interlocking levers 43 and 44 and the rotating shaft 30, the central movable holding portion 38 and the left and right horizontal movable holding portions 40 are biased so as to open with respect to the fixed holding portion 36. Each interlocking wire 48,4
9, 52 and 53 are prevented from loosening.

(Partial Configuration of Rear Holding Member 28 and Drive Transmission System T Therewith) The rear holding member 28 is composed of a fixed holding member 56 and a movable holding member supported therebelow by a four-bar rotating mechanism 58. 57. This movable holding body 57
A pair of arms 57a and 57b is attached to the lower side. In the four-bar rotating mechanism 58, a pair of L-shaped levers 60, 61 are rotatably supported by fixed center shafts 62, 63 on a mounting plate 59 attached to the machine frame 3. The two arms 57a, 57b of the movable holding member 57 are fixed to the permanent center shaft 6 with respect to the first arms 60a, 61a of the movable holding member 57.
4 and 65 rotatably supported. Double lever 6
Interlock rod 66 between second arm portions 60b, 61b
Are connected. One end 67a of the interlocking wire 67 is connected to one second arm 61b. The movable holding member 57 is urged to open with respect to the fixed holding member 56 by the tension coil spring 68 connected to the first arm portion 60a, thereby preventing the interlocking wire 67 from loosening.

(Partial configuration of the horizontal holding member 29 and the drive transmission system T corresponding thereto shown in FIGS. 6 to 9) On the left and right movable plates 2 supporting the left and right folding members 5 in the film folding device 1, The upper holding body 69 is supported on the fixed rail 70 so as to be movable in the left-right direction. A holding portion 69a is attached below the opposing inner edges of the left and right upper holding members 69. The bracket 71 suspended by being connected and fixed to the upper holding member 69 includes a first mounting plate 71a and a second mounting plate 71.
b and a third mounting plate 71c are sequentially combined, and a lever 72 is rotatably supported by a shaft 73 with respect to the third mounting plate 71c. The lower arm 74 of the first arm 72 a of the lever 72 is provided below the upper arm 69.
Is attached. One end 75a of the interlocking wire 75 is connected to the second arm 72b of the lever 72. The lower holding member 74 is urged to open with respect to the upper holding member 69 by the extension coil spring 76 connected to the first arm portion 72a, thereby preventing the interlocking wire 75 from loosening.

(Partial configuration of drive transmission system T shown in FIGS. 10 to 13 and its drive transmission means 78) This drive transmission system T
The rotational driving force of the main motor 77 (drive source) is transmitted to the film drawer 23 (front clamping member), the rear clamping member 28, and the left and right lateral clamping members 29 via the drive transmission means 78. The drive transmission unit 78 includes a torque transmission conversion unit 79 that drives the central movable holding unit 38 of the film drawer 23, and a lateral movable holding unit 4 of the film drawer 23.
0, a torque transmission conversion unit 80 for driving the
, And torque transmission converters 82 and 83 that drive the left and right lateral sandwiching members 29.

As shown in FIG. 13, in each of the torque transmission converters 79, 80, 81, 82, and 83 serving as the drive transmission means 78, a circular shape is formed by a bearing 85 on the outer periphery of a connection boss 84 (drive unit). An interlocking ring 86a (a driven portion) is rotatably supported, and a magnetic powder as an electric transmission medium is provided between an interlocking plate portion 84a protruding from the outer periphery of the connecting boss 84 and the inner periphery of the interlocking ring 86a. A gap 87 filled with the body is provided. One transmission shaft 88 connected to the output shaft 77a of the main motor 77 is inserted into the connection boss 84 and fixed so as to be integrally rotatable. A circular coil 89 (electric control unit) is embedded in the interlocking ring 86a so as to surround the gap 87. When a predetermined DC voltage is applied to the coil 89 and a predetermined current flows, a magnetic flux generated around the coil 89 causes a gap 87.
The magnetic powder inside is connected in a chain shape, and the connecting force of the chain magnetic powder causes the rotational driving force of the connecting boss 84 to be linked.
6a is transmitted with a predetermined torque (substantially proportional to a predetermined current). This predetermined torque corresponds to the transmission driving force described in the claims. When this current is interrupted, the magnetic flux disappears and the magnetic powder becomes free, and the rotational driving force of the connecting boss 84 is not transmitted to the interlocking ring 86a. As shown in FIG. 12, the interlocking ring 86a has a circular interlocking plate 86b.
(Follower) is integrally rotatably mounted.

The film drawer 23 shown in FIGS.
In the partial configuration of the drive transmission system T, the interlocking wire 52 interlocking with the central movable holding portion 38 and the interlocking wire 53 interlocking with the left and right laterally movable holding portions 40 are inserted through tubes 90 and 91, respectively. Interlocking wires 52, 5
3 at one end 52a, 53a side.
Is fixed at one end. Also, this tube 90,
The other end of 91 is fixed in the vicinity of the torque transmission converters 79 and 80, and the interlocking wire 5 pulled out from the other end
The other end portions 52b and 53b of the torque transmission converter 7
9, 80 interlocking plates 86b.

In the partial configuration of the drive transmission system T for the rear holding member 28 shown in FIG. 5, an interlocking wire 67 interlocking with the movable holding body 57 is inserted into the tube 92. One end of the tube 92 is fixed. The other end of the tube 92 is fixed in the vicinity of the torque transmission converter 81, and the other end 67b of the interlocking wire 67 pulled out from the other end.
Are connected to the interlocking plate 86b of the torque transmission converter 81.

In the partial configuration of the drive transmission system T for the left and right horizontal holding members 29 shown in FIGS.
The interlocking wire 75 interlocking with is inserted through the tube 93,
The tube 9 is connected to one end 75a of the interlocking wire 75.
3 is fixed at one end. In addition, both tubes 9
3 is fixed in the vicinity of the torque transmission converters 82 and 83, and the other end 75b of the interlocking wire 75 pulled out from the other ends is an interlocking plate of the torque transmission converters 82 and 83. 86b.

Each of the torque transmission converters 79, 80, 8
In 1, 82 and 83, a locking rod 94 is connected to the outer periphery of the interlocking plate 86b, and a compression coil spring 95 wound around the outer circumference of the locking rod 94 causes the interlocking wires 52, 83 to be connected.
53, 67 and 75 are urged in the direction of loosening.

Each of the torque transmission converters 79, 8
At 0, 81, 82, and 83, locking recesses 96 are formed on the outer periphery of the interlocking plate 86b, and one locking shaft 97 corresponding to each locking recess 96 is parallel to the transmission shaft 88. And with the rotation of each interlocking plate 86b,
The locking recess 96 is locked to the locking shaft 97 so that the interlocking plate 86b does not rotate more than a certain amount.

[Regarding the pre-stretching mechanism 98 and the pre-stretching amount reducing mechanism 98 in the film width direction R shown in FIGS. 6 to 9, 10, 11 and 15] on the left and right movable plates 2 below the left and right upper holding members 69. A guide rod 99 is attached to the left and right upper and lower holding members 69, and the guide rod 99 is inserted into a locking portion 100 attached below the left and right upper holding members 69 so that the left and right upper holding members 69 approach and separate from each other in the left and right direction. It is movable along the guide rod 99. By the compression coil spring 101 wound around the outer periphery of the guide rod 99, the right and left upper holding members 69 are pushed by the locking portions 100 and are urged in a direction approaching each other. One end 103a of the interlocking wire 103 is attached to the pin 102 below the left and right upper holding members 69.
Are connected. The second mounting plate 71b is attached to the rail 105 on the bracket 104 attached to the machine frame 3 below the second mounting plate 71b of the left and right brackets 71.
Are movably supported in the left-right direction.

A cam 106 is attached to a transmission shaft 88 connected to an output shaft 77a of the main motor 77 so as to be integrally rotatable. A lever 107 is supported rotatably about a shaft 107a facing the cam 106, and is urged by a tension coil spring 108 so that the lever 107
The cam follower 109 supported by the tension coil spring 1
It is pressed against the cam 106 by the elastic force 08.

The left and right lateral holding members 29 shown in FIGS.
, The interlocking wire 1 interlocking with the upper holding member 69
03 is inserted into the tube 110, and this interlocking wire 10
One end of the tube 110 is fixed to the movable plate 2 on one end 103a side of the tube 3. In addition, this tube 1
10 is fixed near the cam 106, and the other end 10 of the interlocking wire 103 pulled out from the other end.
3b is connected to the lever 107.

[Details of the film feeding switching device 17 shown in FIG. 14 and FIG. 3] A support shaft 111 is supported at the center of the rear of the machine frame 3 in the up-down direction so as to be rotatable horizontally in the left-right direction. Side plates 112 are attached to both left and right ends of the support shaft 111 so as to be integrally rotatable. The left and right side plates 112
A guide roller 113 is inserted around the outer periphery of the support shaft 111 therebetween. The two side plates 112 protrude forward from the support shaft 111, and the film supply portions 18 are provided on both upper and lower front sides between the two side plates 112, respectively.

In each of the film supply portions 18, an operation lever 114 is supported by left and right side plates 112 so as to be rotatable about a shaft 115.
A comb-shaped movable film guide 116 is attached between them. Above the movable film guide 116, both side plates 11
A comb-shaped fixed film guide 117 is provided between the two. The movable holding roller 11 is provided between the left and right operation levers 114 between the movable film guide body 116 and the shaft 115.
9 (film feed braking unit) is provided. Above the movable holding roller 119, a fixed holding roller 120 (film feed braking unit) is provided between both side plates 112.
The left and right operation levers 114 are urged by a torsion coil spring 118 wound around a shaft 115, and by the urging force,
The movable holding roller 119 is pressed against the fixed holding roller 120. Electromagnetic brakes 121 (film feed braking units) are attached to upper and lower portions of one side plate 112, respectively, and fixed holding rollers 120 are connected to the upper and lower electromagnetic brakes 121, respectively. The movable film guide body 116 and the fixed film guide body 117
And a gap that allows the film 21 to be pulled out.

The film 21 pulled out from the film winding roll 19 having a small width is passed between the two holding rollers 119 and 120 by the upper film feeding portion 18 and is supported between the two film guides 116 and 117. It has become so. The film winding roll 2 having a large width.
The film 22 pulled out from 0 passes between the sandwiching rollers 119 and 120 at the lower film feeding section 18 and is supported between the film guides 116 and 117.

The drive unit 122 provided below the film supply unit 18 controls the left and right side plates 1.
When the pivot 12 is rotated, the upper film supply portion 18 can be in a state corresponding to the film supply position P and the lower film supply portion 18 can be in a state corresponding to the film supply position P. ing.

[Film unwinding direction Q shown in FIGS.
Pre-stretching mechanism 123 and pre-stretching amount reducing mechanism 123] The pre-stretching mechanism 123 and the pre-stretching amount reducing mechanism 123 include the film drawer 23 and the left and right supporting the film drawer 23 movably in the front-rear direction. The film supply unit 18 is provided with the two rotation shafts 30, the rotation belts 42 respectively stretched between the left and right front and rear pulleys 41c, 41c at the left and right ends of the front and rear rotation shafts 41a, 41b, respectively. Each of the holding rollers 119 and 120, the electromagnetic brake 121, and a servo motor 126 (see FIG. 16) described later.

[Controller 124 as Drive Control Means shown in FIG. 16] The controller 124 is built in a control box (not shown). Outside the control box, the input operation unit 12 connected to the controller 124 is provided.
5 are provided. Although not described in detail, the controller 124 includes a central processing unit (CPU), a read-only memory (ROM) storing a predetermined program or the like in advance,
A logic operation comprising a random access memory (RAM) for temporarily storing the operation results of the PU, a backup RAM for storing previously stored data, and the like, connected to an external input circuit and an external output circuit by a bus It is configured as a circuit.

Then, the controller 124 operates as shown in FIG.
, A servo motor 126 for reciprocating the film drawer 23 in the front-rear direction, and a main motor 77 and torque transmission converters 79, 80, 81, 8 shown in FIGS.
2, 83, and both upper and lower electromagnetic brakes 121 shown in FIG.

The servomotor 126 is provided with an encoder 127, and the rotation of the motor 126 is transmitted as electric pulses by the encoder 127, and the number of pulses is detected by the controller 124.

In the main motor 77 also shown in FIGS. 10 and 11, a photoelectric switch 128 (see FIG. 16) is provided in the machine frame 3 and a detection plate (not shown) which is rotated by the rotation of the motor 77. 3) is detected by the photoelectric switch 128. The slit is provided so that the detection signal is generated every cycle operation of the packaging machine.

Based on the setting input data (for example, the following data 1) to 4) by the input operation unit 125, the entire packaging machine is driven and controlled, and the packaging described later is performed. 1) Each torque transmission converter 79, 80, 81, 82, 83
The power supply release timing as the transmission driving force release timing and the power supply amount switching timing as the transmission driving force switching timing are used for the time measured by the controller 124 based on the detection signal from the photoelectric switch 128. A predetermined set time is input, and at the timing when the measured time matches the set time, each of the torque transmission converters 79, 80, 81, 8
Signals are sent to the devices 2 and 83 to perform drive control. This set time can be arbitrarily changed.

2) Each torque transmission converter 79, 80, 8
The energization amount as the transmission driving force value for 1, 82, 83 is set arbitrarily for each of the above timings.

3) Stop timing of the film drawer 23 The number of detection pulses from the encoder 127 is used.
When a film withdrawal dimension is input, a predetermined number of set pulses for stopping film withdrawal corresponding to the input are set to the controller 12.
At the timing when the number of detected pulses reaches the set number of pulses, a signal is sent to the servo motor 126 to stop driving. This set pulse number can be arbitrarily changed.

4) Braking timing of electromagnetic brake 121 The number of detection pulses from encoder 127 is used.
When the pre-expansion set value is input, a predetermined set number of pulses (for turning on the electromagnetic brake 121) corresponding thereto is set by the controller 124, and a signal is sent to the electromagnetic brake 121 when the number of detected pulses reaches the set number of pulses. To control the drive. This set pulse number can be arbitrarily changed.

The backup RAM stores, for each article, a code number, an article size, a film width to be used, and conditions such as the above-mentioned power release timing, power supply switching timing, power supply quantity, stop timing, braking timing, and the like. It is possible to store and drive the packaging machine under the stored conditions based on the code number.

[Packing action centering on the film holding device 27] The packing action will be described with reference to a schematic timing chart shown in FIG. In FIG. 17,
Article receiving stand 25, film drawer 23 and folding members 5, 9
And the horizontal holding member 29 show their mechanical operation state with respect to the elapsed time. The central movable holding portion 38, the horizontal movable holding portion 40, the movable holding member 57, and the lower holding member 74 correspond to the corresponding torque transmission conversion. Parts 79, 80, 81,
It indicates the amount of current supplied to 82 and 83, and indicates an on / off signal for the electromagnetic brake 121. 16 Range of Timing Chart A → B → C) Before the time point A, the film drawer 23 shown in FIGS. 1 and 3 has begun to approach the upper film feeding section 18.
As shown by imaginary lines in FIGS. 4A and 4B, the center movable holding portion 38 and the left and right lateral movable holding portions 40 are opened with respect to the fixed holding portion 36 by the film drawer 23. Further, the electromagnetic brake 121 of the film supply unit 18 is in the ON state, and the film 21 is being braked.

After the time point A, when the film drawer 23 almost reaches the upper film feeding section 18, a photoelectric switch 129 (FIG. 16) disposed near the film feeding section 18 is provided.
) Detects the film drawer 23. Then, based on the detection signal, the controller 124 operates as shown in FIG.
When the two torque transmission converters 79 and 80 shown in FIG. 13 are energized, the rotational driving force of the connecting boss 84 that rotates together with the transmission shaft 88 by the main motor 77 is transmitted to the interlocking ring 86a with a predetermined torque. Therefore, both interlocking plates 86b shown in FIGS. 11 and 12 rotate against the elastic force of the compression coil spring 95, and pull the two interlocking wires 52 and 53. And
The force for pulling the two interlocking wires 52 and 53 is transmitted to the two interlocking wires 48 and 49 via the two rotation shafts 30 and the two sliding cylinders 31 shown in FIGS. Therefore, the film drawer 2
In the stop state of No. 3, the center movable holding portion 38 and the left and right lateral movable holding portions 40 close to the fixed holding portion 36, and the front edge 21a of the film 21 is held therebetween. Thereafter, at a point in time when a predetermined time has elapsed after the photoelectric switch 128 issues the detection signal, the electromagnetic brake 121 is turned off, and the braking on the film 21 is released. Then, the film drawer 23 separates from the upper film supply portion 18, and
At time B, the film 21 is almost pulled out to the packaging section S.

By stopping the drive of the servo motor 126 for reciprocating the film drawer 23 shown in FIG. 3 in the front-rear direction, the film drawer 23 draws out the film 21 and stops at time C. The draw-out dimension of the film 21 is set according to the longitudinal dimension of the article 26.

Preliminary extension operation in the film withdrawal direction Q (range from B to C) The controller 124 controls the electromagnetic brake 1 smaller than the set number of pulses for stopping the withdrawal of the servo motor 126 described above.
The ON signal of the electromagnetic brake 1217 is sent with the ON set pulse number of 21. Therefore, the electromagnetic brake 121 operates before the film drawer 23 stops, and the film 2 held between the two holding rollers 119 and 120 shown in FIGS.
1 is stopped. Therefore, the film 21 is preliminarily stretched in the drawing direction Q by the film drawer 23 that moves thereafter. When the preliminary extension set value is changed by the input operation unit 125, the braking timing of the electromagnetic brake 121 with respect to the stop timing of the film drawer 23 can be changed via the controller 124.

In the range from A to B, the article 26 (see FIG. 1) is moved by the article transport conveyor 24 toward the article receiving table 25 in the lowest state, and stops on the article receiving table 25. For example, when the width size of the film to be used is small according to the size of the article 26, the upper film supply unit 18 corresponds to the film supply position P as shown in FIG. 2, the left and right movable plates 2 of the film folding device 1 are set at narrow intervals together with the left and right folding members 5 as shown in FIG. Also, the interlocking wire 103 shown in FIGS. 11 and 15 is loosened with the rotation of the cam 106, and the left and right horizontal sandwiching members 29 are moved by the elastic force of the compression coil spring 101 as shown in FIGS. L is set.

(Range of timing chart B → C → D) During the film unwinding operation, at the time B when the number of pulses smaller by a predetermined amount than the set number of pulses for stopping the film unwinding is counted by the encoder 127, FIG. 1
When the respective torque transmission converters 81, 82, 83 shown in FIG.
a is transmitted at a predetermined torque. Therefore, FIG.
12, each interlocking plate 86b rotates against the elastic force of the compression coil spring 95, and pulls the interlocking wires 67 and 75. Then, the force for pulling the interlocking wire 67 is transmitted to the four-bar rotating mechanism 58 by the rear holding member 28 shown in FIG. 5, and the movable holding body 57 closes to the fixed holding body 56. Therefore, immediately before the upper film feeding section 18, the rear portion (the rear edge 21 b after cutting) of the film 21 is sandwiched between the sandwiching bodies 56 and 57. The force for pulling both interlocking wires 75 is transmitted to the lever 72 by the left and right lateral holding members 29 shown in FIGS. 6 to 8, and the lower holding member 74 is held by the holding portion 69 a of the upper holding member 69.
Close to Therefore, the left and right edge portions 2 of the film 21
1c is held between the holding members 69 and 74. The energization of each of the torque transmission converters 81, 82, and 83 is started before the film drawer 23 is stopped. However, as an actual state, after the energization, a mechanical operation is performed, and the rear holding member 28 and the right and left When the two lateral sandwiching members 29 sandwich the film 21, it is the time point C at which the film drawer 23 stops, and the film 21 is in a stopped state.

* Preliminary stretching operation in the film width direction R (C
When the interlocking wire 103 shown in FIGS. 11 and 15 is pulled along with the rotation of the cam 106, the left and right lateral holding members 29 resist the elastic force of the compression coil spring 101 as shown in FIGS. And is set at the widest interval L. Therefore, the film 21 is pre-stretched in the width direction R. On the other hand, in the range from the time point B to the time point D, as described above,
The article 26 on the article receiving table 25 rises from below toward the film 21 on which the a, 21c and the rear portion (the rear edge 21b after cutting) are sandwiched. Immediately before the point D before the article 26 rises, the rear portion of the film 21 is cut by the cutter 130 (see FIG. 1) in the article receiving table 25. Until the time point D, the pre-stretched state is maintained, and the article receiving table 25 further moves up to the time point E.

(Timing chart D → E → A time range) * Preliminary elongation reduction operation (D → E)
At the time point D at which a predetermined time has passed since the photoelectric switch 128 emitted the detection signal, the controller 124 issues a command to the servo motor 126 to move the film drawer 23 to the upper film feeding unit 18. Approach. Therefore, the film 21 is loosened, and the amount of preliminary elongation in the drawing direction Q decreases. This pre-elongation amount reduction state is continued until time H.

* Preliminary elongation reduction operation in the film width direction R (range from D to A) When the interlocking wire 103 shown in FIGS. 11 and 15 is loosened with the rotation of the cam 106, as shown in FIGS. The left and right lateral holding members 29 are moved by the elastic force of the compression coil spring 101 and are set to be narrower than the widest interval L. Therefore,
The film 21 is loosened, and the amount of preliminary elongation in the width direction R decreases. This pre-elongation amount reduction state is continued until almost point A.

At the time point D (energization amount switching timing) when the time measured by the controller 124 on the basis of the detection signal from the photoelectric switch 128 coincides with a predetermined set time, the energization amount to the torque transmission converters 81, 82, and 83 is changed. Decreases, the predetermined torque transmitted from the connection boss 84 to the interlocking ring 86a also decreases. Accordingly, the rear end edge 21b of the film 21 is formed by the rear holding member 28 and the left and right horizontal holding members 29.
In addition, the holding force between the fixed holding body 56 and the movable holding body 57 that hold the left and right end edges 21c and between the upper and lower holding bodies 69 and 74 is reduced.

In synchronization with the operation of reducing the amount of pre-extension and the holding force, the lower side of the film 21 on which the front left and right edges 21a and 21c and the rear edge 21b are held is placed on the article receiving table 25. Near the time point D and further rises, and the film 21 is stretched.

In the vicinity of the time point D, the rear folding member 9 advances toward the front folding member 14 in the film folding device 1, and the left and right folding members 5 start closing each other. Next, as described above, at the point E (the timing of switching the amount of energization) when the measurement time matches the predetermined set time, the torque transmission conversion unit 7
When the amount of electricity supplied to 9, 80 decreases, the predetermined torque transmitted from the connecting boss 84 to the interlocking ring 86a also decreases. Accordingly, the holding force for holding the front edge 21a of the film 21 by the fixed holding portion 36, the central movable holding portion 38, and the left and right horizontal movable holding portions 40 in the film drawer 23 is reduced.

When the article receiving table 25 rises most at the point of E → F, the film 21 covers the upper side of the article 26. After the time point E, the folding members 5 and 9 of the film folding device 1 start contacting the film 21 and reach the time point F and the folding members 5 and 9 are placed under the article 26 under the film 2.
1 and the rear folding member 9 receives the article 26.

Next, as described above, at the time F (energization release timing) when the measured time coincides with the predetermined set time as described above, the torque transmission conversion unit 81 is synchronized with the folding operation. When the energization is released, the predetermined torque is not transmitted from the connecting boss 84 to the interlocking ring 86a. Therefore, the interlocking plate 86b rotates by the elastic force of the compression coil spring 95, and the interlocking wire 67
Is released, and the movable holding body 57 opens with respect to the fixed holding body 56. Accordingly, the holding of the film 21 against the rear edge 21b is released.

Next, at the time point G, at the time point G, the rear folding member 9 and the left and right folding members 5 of the film folding device 1 further fold the film 21. The article receiving stand 25 is descending.

In synchronization with the folding operation, the torque transmission converters 80, 82, 83 at the point of time G (energization release timing) when the measurement time matches the predetermined set time as described above.
Is stopped, the predetermined torque is not transmitted from the connecting boss 84 to the interlocking ring 86a. Therefore, the interlocking plate 86b is rotated by the elastic force of the compression coil spring 95, the interlocking wires 53 and 75 are loosened, the left and right horizontal movable holding portions 40 are opened with respect to the fixed holding portion 36, and the left and right lower holding members are opened. 74 opens to the left and right upper holding bodies 69. Accordingly, the gripping of the front edge 21a of the film 21 with respect to the left and right portions and the left and right edge portions 21c is released.

(Timing H) Next, at the time H, the rear folding member 9 and the left and right folding members 5 are closed by the film folding device 1, and the article 26 is placed on the rear folding member 9. The folding of the film 21 from three sides under the article 26 is completed. Then, the article 26 is carried forward by the article carrying-out member 16b (see FIG. 1) while being pressed from above by the article holding plate 16a (see FIG. 1). The front folding of begins.

In synchronization with the folding operation, as described above, when the current supply to the torque transmission conversion unit 79 is released at the time point H (the power supply release timing) when the measurement time matches the predetermined set time, the connection boss 84 Therefore, the predetermined torque is not transmitted to the interlocking ring 86a. Therefore, the interlocking plate 86
b rotates by the elastic force of the compression coil spring 95, the interlocking wire 52 is loosened, and the central movable holding portion 38 opens with respect to the fixed holding portion 36. Therefore, the front edge 21a of the film 21
Is released from the center.

(Timing chart H → A time range)
Further, the article 26 placed on the rear folding member 9 is carried out toward the heater 15 by the article carrying-out member 16b, and the front folding of the film 21 is completed. The article 26 is stopped on the heater 15 by the stopper 131 (see FIG. 1), and the overlapping portion of the film 21 is brought into close contact with the heat under the article 26.

(When the width size of the film used is large) The lower film feeding portion 18 shown in FIG. 1 corresponds to the film feeding position P, and the left and right sides of the film folding device 1 are linked to this position. The movable plate 2 is set at wide intervals together with the left and right folding members 5. In this case, the upper and lower holding members 69, 74 of the left and right horizontal holding members 29, the bracket 71, and the like are also integrally spread together with the left and right movable plates 2. The basic wrapping operation is the same as that described above, except that the power release timing, the power switching timing, the power supply, the stop timing of the film drawer 23, the braking timing of the electromagnetic brake 121, and the like are changed according to the article 26. You. The present embodiment has the following features (a) to (nu) (other than the other technical ideas described later).

(B) Left and right lateral holding members 29 opposed to each other
Is provided with a pre-stretching mechanism 98 for performing a pre-stretching operation capable of stretching the film 21 sandwiched between the films 21 in the width direction R thereof. Further, the film 2 pulled out by the drawer 23
1 is provided with a pre-stretching mechanism 123 for performing a pre-stretching operation capable of extending 1 in the pull-out direction Q. Therefore, it is possible to obtain a good wrapping state in which the wrapped film 21 has a sufficient tension.

(B) The pre-stretching amount decreasing operation is started while the article 26 rises toward the film 21 pre-stretched in the packaging section S, particularly, while the article 26 is almost in contact with the film 21. Pre-extension amount reducing mechanism 98, 123
Is provided. Therefore, the article 26 having a significantly lower strength
(Tray) is pressed against the film 21 and the amount of warpage can be reduced. Therefore, when the tray is restored after packaging, wrinkles due to loosening of the packaged film 21 are less likely to occur on the upper surface of the tray against which the film 21 is pressed, and a good packaging state without wrinkles can be obtained.
Here, “substantially contact” means that the upper surface of the tray is
And a range from immediately before contacting the lower surface to a point immediately after contact with the lower surface.

(C) Since the film drawer 23 is also used as the front holding member, the braking timing (ON signal) of the electromagnetic brake 121 is controlled by changing the set number of pulses, so that the amount of preliminary elongation in the film draw direction Q can be reduced. Can be easily changed. Therefore, especially for articles 26 (tray) having extremely poor strength, the amount of pre-stretching in the film withdrawal direction Q is reduced to reduce the reaction force received from the film 21, and similar to (b) above, no wrinkles A good packaging state can be obtained.

(D) The drive transmission means 78 is controlled by the controller 124 in accordance with the operation of reducing the amount of preliminary extension of the left and right lateral holding members 29 by the above-mentioned preliminary extension amount reducing mechanism 98. Therefore, when the folding is performed by the left and right folding members 5, the pinching force of the left and right lateral clamping members 29 against the left and right end edges 21 c of the film 21 starts the operation of reducing the amount of preliminary extension in the film width direction R so that they can be removed. It is set small in synchronization with the timing. Therefore,
It is possible to prevent the article 26 and the film 21 from being damaged and to obtain a good packaging state in which the film 21 after packaging has sufficient tension.

(E) The drive transmitting means 78 is controlled by the controller 124 in response to the operation of reducing the preliminary extension amount of the film drawer 23 by the preliminary extension amount reducing mechanism 123. Therefore, when the rear folding member 9 performs folding, the clamping force of the rear clamping member 28 against the rear portion (the rear edge 21b after cutting) of the film 21 is reduced by the amount of preliminary elongation in the film withdrawal direction Q so that the film 21 can be released. It is set small in synchronization with the operation. Therefore, it is possible to further prevent the article 26 and the film 21 from being damaged, and to obtain a good packaging state in which the film 21 after packaging has a sufficient tension.

(F) Since the front portion of the film 21 on the side of the front edge 21a held by the film drawer 23 (front holding member) is finally folded, the front edge 21a is lifted by the article 26 and the film drawer 23 is lifted. It is necessary to keep a margin at the front of the film 21 so as not to fall out from the (front holding member). Therefore, under the control of the drive transmission means 78, when the front folding member 14 performs folding, the pinching force of the film drawer 23 (front clamping member) against the front end edge 21a of the film 21 is reduced so that it can be released. 25 is set to be small in synchronization with the completion of the ascent operation.

(G) As shown in FIG. 10, each of the torque transmission converters 79, 80, 81,
When the rotational driving force is transmitted from the main motor 77 side to the film drawer 23 (front clamping member), the rear clamping member 28, and the left and right horizontal clamping members 29, the controller 124 controls the amount of power supply. You can do it. Therefore, the pinching force on the film 21 can be easily changed.

For example, in the timing chart shown in FIG. 17, the center movable holding portion 38 of the film drawer 23 is
In the left and right horizontal movable holding portions 40, in the range from A to E,
In the movable holding member 57 of the rear holding member 28 and the lower holding member 74 of the left and right lateral holding members 29, the amount of excitation current, which is the amount of exciting current to the coil 89 (see FIG.
Has increased. Therefore, as described above, when the film 21 is pulled out to the wrapping portion S by the film drawer 23 and when the film 21 is pre-stretched by the pre-stretching mechanisms 98 and 123, the film front edge 21
a, the rear portion of the film (the rear edge 21b after cutting) and the left and right end edges 21c are set so that they do not come off, so that sufficient tension can be applied to the film 21.

In the timing chart shown in FIG. 17, the center movable holding portion 38 of the film drawer 23 is in the range of F → H, and the left and right horizontal movable holding portions 40 of the film drawer 23 are in the range of E → G. In the range, at the time of D → F in the movable holding body 57 of the rear holding member 28, and in the range of D → G at the lower holding body 74 of the left and right lateral holding members 29, the exciting current amount to the coil 89 is obtained. A certain amount of current is reduced to Ts. Therefore, as described above, when each of the folding members 5, 9, and 14 comes into contact with the film 21 and is folded,
Since the holding force for the film front edge 21a, the film rear portion (the rear edge 21b after cutting), and the left and right edge portions 21c of the film is set so that they can be removed, the article 2
6 and the film 21 can be prevented from being damaged.

(H) The drive transmitting means 78 transmits the rotational driving force from the main motor 77 side to the film drawer 23.
(Front clamping member), rear clamping member 28, left and right lateral clamping members 2
At the time of transmission to the ninth side, the power release timing, the power supply amount switching timing, and the power supply amount can be controlled by the controller 124. For example, in the timing chart shown in FIG. 17, the control of the energization amount switching timing is performed at each time point of D and E, and the control of the energization release timing is performed at each time point of F, G and H. Therefore, these controls are facilitated, and more accurate film tension adjustment can be performed according to the article 26.

(I) In each of the torque transmission converters 79, 80, 81, 82, 83 of (A), the connecting boss 8
Magnetic powder (filled in the gap 87) is used as an electric transmission medium capable of interlocking the interlock 4 with the interlocking ring 86a.
In such a magnetic powder system, there is no difference between the static torque and the dynamic torque, and a stable torque can be obtained. Also,
Regardless of the magnitude of the slip rotation, not only the transmission torque is constantly constant, but also extremely stable during repeated operation.

(G) Main motor 77 as drive source
Is not directly controlled, but the drive transmission means 78 in the middle of the drive transmission system T is controlled. Therefore, the film drawer 23
(Front clamping member), rear clamping member 28, left and right lateral clamping members 2
9, one main motor 77 can also be used as a drive source for each control target even if there are a plurality of control targets such as 9 and their control conditions (power release timing, power supply amount switching timing, power supply amount) are different. 27
Structure can be simplified.

[Other technical ideas] The technical ideas (other than the claims) that can be grasped from each embodiment will be described together with the effects. (A) A drive transmission means (78) according to any one of claims 2 to 6, comprising: a driving portion (84) to which a driving force is transmitted from a driving source (77); Holding members (23, 28, 29) for driving force from the part (84)
Driven part (86a, 86b) transmitting to the side, an electric transmission medium (magnetic powder in the gap 87) capable of interlocking the driven part (84) and the driven part (86a, 86b), And an electric control unit (89) for controlling the transmission medium (87). The electric transmission medium (87) is driven by the driving unit (8) in response to an electric signal applied to the electric control unit (89).
The driving force transmitted from 4) to the driven portions (86a, 86b) can be changed. Therefore, the pinching force on the film (21) can be easily changed.

(B) In any one of claims 2 to 6 or (a), the film holding force of the holding members (23, 28, 29) is reduced corresponding to the film folding operation. Thus, when the driving force from the driving source (77) is transmitted to the holding members (23, 28, 29), the driving control means (12) controls the transmitted driving force.
4) was provided. Therefore, the article (26) and the film (2)
The damage of 1) can be prevented.

(C) The holding member (2) according to any one of claims 2 to 6 or (a), corresponding to the pre-extension amount reduction operation after the completion of the pre-extension operation.
3, 28, 29), the driving force from the driving source (77) is used to reduce the film holding force.
A drive control means (124) for controlling the transmission driving force when transmitting to the (3, 28, 29) side is provided. Therefore, damage to the article (26) and the film (21) can be prevented.

(D) In any one of claims 2 to 6 or (a), the pre-stretching operation corresponds to the pre-stretching amount decreasing operation and the film folding operation. Member (23, 28, 29)
The drive source (7
7) A drive control means (124) for controlling the transmitted driving force when transmitting the driving force from the side to the holding members (23, 28, 29). Therefore, damage to the article (26) and the film (21) can be prevented.

[0082]

According to the stretch film packaging machine of the present invention, it is possible to prevent damage to articles and films and to obtain a good packaging state.

[Brief description of the drawings]

FIG. 1 is a schematic side sectional view showing a stretch film packaging machine according to an embodiment.

FIG. 2 is a partially cutaway plan view showing a film folding device of the packaging machine.

FIG. 3 is a partially cutaway plan view showing a film drawer, a pre-extension mechanism, a pre-extension amount reduction mechanism, and the like of the packaging machine.

4 (a) is X ₁ over X ₁ line partially enlarged sectional view of FIG. 3, (b) is X ₂ over X ₂ line portion enlarged sectional view of FIG. 3, (c) is 3 FIG. ₃ is an enlarged sectional view taken along line X ₃ -X ₃ of FIG.

FIG. 5 is an enlarged sectional view taken along the line YY of FIG. 1, showing a rear holding member and the like of the packaging machine.

FIG. 6 is a partially enlarged plan view of FIG. 1 showing the left and right lateral holding members, the pre-stretching mechanism, the pre-stretching amount reducing mechanism, and the like of the packaging machine.

7 is a Z ₁ over Z ₁ line partially enlarged sectional view of FIG.

8 is a Z ₂ over Z ₂ line portion cross-sectional view of FIG.

9 is a Z ₃ over Z ₃ line portion enlarged sectional view of FIG.

FIG. 10 is a partially enlarged plan view showing each drive transmission means and the like of the drive transmission system.

FIG. 11 is a partially enlarged front view of the same.

FIG. 12 is a partially enlarged cross-sectional view showing each drive transmission unit.

FIG. 13 is a partially enlarged sectional view showing each drive transmission unit.

FIG. 14 is a sectional view showing the film feeding switching device of FIG. 1 in more detail;

15 is a Z ₄ over Z ₄ line partially enlarged sectional view of FIG. 11.

FIG. 16 is a schematic electric block circuit diagram.

FIG. 17 is a schematic timing chart.

[Explanation of symbols]

5, 9, 14: film folding member, 18: film feeding portion, 21: film, 21a, 21b, 21c: film edge, 23: film drawer (front clamping member), 26
... Articles, 28 ... Back clamping members, 29 ... Left and right lateral clamping members,
98, 123 ... preliminary extension mechanism and preliminary extension amount reduction mechanism,
77: a main motor as a driving source which is a clamping force variable means; 78: a drive transmission means which is a clamping force variable means;
9, 120: nipping roller as a film feed braking unit;
121: Electromagnetic brake as film feed braking unit, 1
24: controller as drive control means, S: packaging part, T: drive transmission system, Q: film unwinding direction, R: film width direction.

Claims (6)

[Claims] 1. A film drawer (23) which draws a supply film (21) toward or away from a film supply part (18) to a packaging part (S), and a film edge of the supply film (21). (21a, 2
1b, 21c) (23, 28, 29) which are driven to be able to take a state of holding and a state of releasing the holding.
And a pre-stretching means (98, 123, etc.) for performing a pre-stretching operation capable of stretching the supply film (21) drawn into the wrapping portion (S) by the film drawer (23). ) And the holding members (23, 2)
8, 29) at the film edge (21a, 21b, 21c)
The article (2) is sandwiched and pre-stretched.
6) A stretch film packaging machine for packaging an article (26) by folding the supply film (21) covering the upper side of the article (26) under the article (26) with a film folding member (5, 9, 14). (23, 28, 29), in addition to the pinching force varying means (77, 78) for changing the pinching force of the film edges (21a, 21b, 21c), the supply film (pre-stretched in the packaging section (S)) While the article (26) is ascending toward 21), the pre-extension for performing the pre-extension amount reduction operation of bringing at least one of the opposing holding members (23, 28, 29) closer to the other. A film clamping device in a stretch film packaging machine, characterized in that it is provided with an amount reducing means (98, 123, etc.). The holding force varying means includes a holding member (23, 2).
8, 29) and a drive transmission means (78) provided in a drive transmission system (T) from the drive source (77) to the holding members (23, 28, 29). When transmitting the driving force from the driving source (77) to the holding members (23, 28, 29), the drive transmitting means (78) controls the transmitted driving force by the driving control means (124). The film holding device in a stretch film packaging machine according to claim 1, wherein the film holding device can be controlled. 3. The drive transmission means (7) according to claim 2,
8) is a holding member (2) for receiving the driving force from the driving source (77).
3, 28, 29), the drive control means (1
24) A film holding device in a stretch film packaging machine, wherein the transmission driving force release timing and the transmission driving force switching timing can be controlled by the above (24). 4. The holding member (23, 28, 29) is provided in a film withdrawing direction (Q) by the film withdrawing body (23).
A holding member (29) opposed to each other in the film width direction (R) perpendicular to the film.
9), a pre-stretching operation is performed to relatively separate the opposed sandwiching members (29) so that the supply film (21) sandwiched by both film edges (21c) can be extended, and the opposed sandwiched members (29) are stretched. The pre-elongation amount reducing means (98 or the like) can adjust the interval (L) of the supply film (21) in which both film edges (21c) are clamped by the opposed clamping members (29). A pre-stretching amount reducing operation of relatively approaching the opposing holding members (29) so as to reduce the amount of extension of the object (26) can be performed to adjust the distance (L) between the opposing holding members (29). ) Is the supply film (2)
This pre-elongation amount decreasing operation is started during the ascending contact substantially in 1). In response to the pre-elongation amount reducing operation, the holding member (29) facing in the film width direction (R) is moved. The film holding device in a stretch film packaging machine according to claim 2 or 3, further comprising a drive control means (124) for controlling the drive transmission means (78). 5. A film feed braking portion (119, 120, 121) for braking the drawing of the supply film (21) by the film drawer (23), and the holding members (23, 28, 29) comprise a film drawer. (23), and a holding member (28) facing the holding member (23) in a film withdrawing direction (Q) by the film drawer (23). 123 etc.) is a film drawer (2
Before the film feed unit (21) is pulled out and stopped with the distance from the film feed unit (18), the film feed braking unit (119, 120, 121) brakes the drawing of the supply film (21). And supply film (2
And a drive control means (124) for controlling the braking timing of the film feed braking portion (119, 120, 121) with respect to the stop timing of the film drawer (23). The film clamping device in the stretch film packaging machine according to any one of claims 2 to 4, wherein the film clamping device is provided. 6. A pre-stretching amount reducing means (123) comprises a supply film (21) in which both film edges (21a, 21b) are sandwiched by opposing sandwiching members (23, 28).
Film drawer (23) so as to reduce the amount of elongation of the film
Can be performed to approach the film supply section (18), and the pre-extension amount reducing operation is started during the upward movement of the article (26) substantially contacting the supply film (21). The drive transmission means (7
The film holding device in a stretch film packaging machine according to claim 5, further comprising a drive control means (124) for controlling (8).