JPH0520645Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention is a film holding device in a stretch film packaging machine, specifically, a film that has been fed out and stretched into the packaging section of the packaging machine is folded into an object to be packaged by a folding mechanism. The present invention relates to a film holding device that clamps both widthwise edges of the film and releases it at a predetermined timing.

(Prior Art and its Problems) Conventionally, a stretch film has been provided with a film transfer path for feeding out a strip-shaped stretch film to a packaging section, and the wrapping section has a folding mechanism for folding the stretched film into an object to be packaged. This is a film packaging machine in which film holding members are arranged on both sides of the film transport path, one or both of the holding members are divided into a plurality of parts along the film transport direction, and each holding member folds the film. A device is known in which the film holder is activated so that it is released at the timing linked to the movement (Japanese Patent Application Laid-Open No. 1983-1999).
Publication No. 125412).

That is, according to the above-mentioned conventional publication, front and rear press members 26 and 37 are provided to clamp both ends of the packaging film F in the width direction when folding the film, and at least one of the press members 26 and 37 is connected to the center press part 26a and the center press part 26a. It is divided into left and right horizontal pressing portions 26b, and both pressing portions 26a, 26b are respectively linked with vertical movement mechanisms for vertically moving them separately.

However, the conventional device has a structure in which the holding member and a solenoid for operating the holding member are provided separately from the film feeding mechanism that feeds out the film to the packaging section. Specifically, an endless belt 22, 23, 33, and 34 are alternately arranged vertically so that the lower side of the upper belt and the upper side of the lower belt are on the same plane, and the widthwise edge of the film F is inserted into the upper and lower belts in a wavy manner. The film is conveyed, and the pressing members 26 and 37 are arranged below the conveyance belt.

The pressing members 26 and 37 are used to hold the film F in the packaging section.
is conveyed and expanded, and before the packaged item is pushed up against the film, it is moved upward by the excitation of the solenoid.
The edge of the film is clamped and fixed together with the conveyor belt in cooperation with the pressure receiving plate 27, and the solenoids of the holding members 26 and 37 are turned off at a predetermined timing in conjunction with the film folding operation, thereby clamping the film. It is a liberating structure.

However, the conventional device described above requires a holding member for clamping or releasing the film separately from the film feeding mechanism, which complicates the device and requires a pressing structure that requires excitation of a solenoid for the film clamping operation. As a result, the solenoid is energized for a long time, causing seizure, resulting in poor durability.To prevent this, an improved structure of the solenoid (Figures 17 and 18) must be adopted.
A divided structure of the holding member that requires a plurality of solenoids has the disadvantage of significantly increasing costs.

It is an object of the present invention to provide a film holding device which eliminates such conventional problems, has a simple structure, improves durability, and can reduce costs.

(Technical Means for Solving the Problems) The film holding device of the present invention has a pair of endless chains rotatably disposed on both sides of the film transfer path, and an endless chain attached to the outer periphery of each chain. An elastic belt is provided around the circumference, and a plurality of swingable clips are attached to the outer surface of each chain with the center pivoted, and the outer part of each chain is divided into three parts along the direction of movement of each chain. each clip has a portion at one end thereof that can fit with the elastic belt and grip a side edge of the stretch film, and the other end is engaged with and guided by the guide member. an actuating piece; each guide member is provided with an elastic member that directly or indirectly biases the actuating piece of the clip to hold the film;
The present invention is characterized in that a solenoid is connected which moves a guide member by energizing it in synchronization with the timing of the film folding operation of the folding mechanism and releases the film grip of the clip.

(Function) According to the present invention, the plurality of clips attached to the outer surface of the endless chain are moved upward by the biasing member of the guide member while the operating pieces thereof are engaged and guided by the guide member. As a result, one end of the clip fits into the elastic belt around the outer periphery of the chain, firmly holding both edges of the stretch film, and in this state, the film is transported along the transport path to the packaging section. do.

The film that has been conveyed to the packaging section and stopped is still held between one end of the clip and the elastic belt. In conjunction with the folding operation, the three guide members are sequentially moved by the excitation of the solenoid, which causes the operating piece of the clip that engages with the guide member to move downward, causing the clip to swing and one end to become elastic. The film holder is released by separating from the body belt.

(Example) Embodiments of the present invention will be explained with reference to the drawings.

FIG. 3 is a longitudinal sectional side view of the stretch film wrapping machine of the embodiment, and in the figure, numeral 10 indicates the machine frame of the stretch film wrapping machine.

As shown in FIGS. 3 to 5, this machine frame 10 is constructed into a substantially rectangular parallelepiped, and the left side in FIG.
0b, and the right side is the back surface 10c.

There is a loading port 10 approximately in the center of the front surface 10b of the machine frame 10.
a is opened, and the machine frame 1 is opened from before the loading port 10a.
A carry-in conveyor 11 is provided throughout the interior of the vehicle.

The carry-in conveyor 11 is composed of a pusher conveyor 12 and a belt conveyor 14, and conveys the packaged items to a predetermined position on an elevator head 13 disposed at the discharge end side of the pusher conveyor 12.

As shown in FIG. 4, the pusher conveyor 12 is
The chain 12 is connected between a pair of sprockets 12a, 12a provided in front of the loading port 10a and a pair of sprockets 12'a, 12'a provided inside the machine frame 10.
b, 12b, and the chain 12b, 12b
A pusher 12c, 12c is provided at a predetermined position, respectively, and one article to be packaged is carried in each time the chains 12b, 12b rotate half a rotation. The pusher conveyor 12 pushes the packaged items placed on the conveyance surface 12d with pushers 12c and conveys them.
A roller 14a of the belt conveyor 14 is provided nearby so as to freely rotate.

The belt conveyor 14 is located at the rear of the elevator head 13 (FIGS. 3 and 4) in correspondence with the roller 14a.
A roller 14b is freely rotatable on the right side of the figure, and six belts 14c,
14c... is strung up. The belt conveyor 14 transports the packaged items brought in by the pusher conveyor 12 to the rear end side of the elevator head 13.

The elevator head 13 is installed on a head mounting base 13b supported by a pair of arms 13a, 13a that swing up and down, and is preset in accordance with the rotation of the motor M1 that drives the carry-in conveyor ₁₁ . It moves up and down at the same timing. This timing is set by a timing cam (not shown) provided in a mechanism for transmitting the power of the motor _M1 to the head mount 13b. The elevator head 13 is used to push up the packaged items carried in by the carry-in conveyor 11 to a predetermined packaging section 9. Therefore, the lower end position of the elevator head 13 is set at approximately the same height as the conveyance surface 12d of the carry-in conveyor 11, and the upper end position is set at approximately the same level as the packaging section 9, that is, the horizontal folding plates 17, 17 and the front folding plate 16, which will be described later. The position will be set to

Incidentally, as in the conventional packaging machine, the object to be packaged is pushed up by a stretch film while being pushed up to the packaging section 9 by the elevator head 13, so that the upper surface is covered by the stretch film, and this will be explained later. This will be explained in detail.

In addition, the carry-in conveyor 11 is replaced by the pusher conveyor 1.
By combining both conveyors 12 and 14 instead of using only either one of the two conveyors or the belt conveyor 14, when assembling and manufacturing the packaging machine, simply by reassembling the same parts, the direction of conveyance of the product after wrapping can be changed. It is designed so that it can be manufactured in a packaging machine that operates in the forward direction rather than in the backward direction (as in the case of the embodiment), and is detailed in Japanese Utility Model Application No. 1987-76300, which was previously filed by the applicant of the present invention.

The elevator head 13 and head mounting base 1
3b is formed into a slit shape as shown in FIGS. 4 and 5, and when the elevator head 13 is moved up and down, the belts 14c and 1 of the belt conveyor 14 are
4c... from coming into contact with the elevator head 13 and the head mounting base 13b.

The elevator head 13 has a plurality of small blocks 1
3c, 13d, 13e..., and each small block 13c, 13d, 13e... is provided to be able to rise and fall freely in response to a force applied from a predetermined direction, and is biased upright by a coil spring (not shown) or the like. has been done. The small block 13c receives a force from above in FIG. 4, and the small block 13d receives a force from below in FIG.
The small blocks 13e are constructed so as to be tilted by a force from the left side in FIG. 4, so that the stretch film folding operation described later can be carried out without any hindrance.

In addition, 15 in FIG. 3 is a positioning plate provided at the rear of the elevator head 13.
The object to be packaged brought in in step 4 is positioned with reference to the rear end.

As shown in FIG. 4, a pair of transverse folding plates 17, 17', a front folding plate 16, and a rear folding roller 18 are arranged around the packaging section 9, and these are used to push up the package by the elevator head 13. An opening is formed through which the packaged object passes.

The horizontal folding plates 17, 17' are used to perform horizontal folding in the left-right direction, and are provided so as to be slidable in the vertical direction in FIG. 4, and are configured to slide in conjunction with each other in opposite directions.

The front folding plate 16 performs forward folding after the horizontal folding is completed, and is provided so as to be slidable in the left and right directions in FIG. 4, and is driven independently of the horizontal folding plates 17, 17'. An unloading pusher 30 is disposed above the front folding plate 16.

The carry-out pusher 30 transfers the packaged items that have been subjected to the front folding and the horizontal folding to the rear folding roller 18.
In the process of this movement, the post-folding roller 18 performs post-folding to complete the packaging. The packaged items that have been wrapped are placed on heat belt 1.
While being transferred at step 9, the bottom folded portion is heat welded.

The above is a description of the packaging mechanism mainly for transporting objects to be packaged in the packaging machine of the embodiment, and the stretch film supply section and feeding device will be described below.

The stretch film supply section is located on the right side of the packaging machine, as shown in FIG. 20 in the figure,
20' and 21, 21' are supporting rollers that support the stretch film rolls A ₁ and A ₂ , respectively;
The structure is such that two types of stretch film rolls A ₁ and A ₂ having different widths can be selectively used. FIG. 5 shows a case where a film roll A ₁ is used, and the stretch film A _{' 1} unwound from the roll A 1 is wound around the right support roller 20' and pulled out, and then passed through the end detection roller 40. It is inserted between the upper and lower feeding belts 27, 27', 28, 28'. The belts 27, 27', 28, 2
8' constitutes a film advance device 60, 60' (FIG. 6).

Next, to briefly explain the feeding and transport of the stretch film _A'1 , vectors 27, 27',
The film inserted between 28 and 28' is fed out by the rotation of belts 27, 27', 28 and 28'. The film is fed out to the front end of the belts 27, 27', 28, 28' (left side in Fig. 5).
Film A' ₁ is then held at its both ends between a group of clips 7, 7' and rubber belts 6d, 6'd, which will be described later, and is unrolled to a length necessary for packaging. ' ₁ is cut to the required length.
The cut film A″ ₁ is placed in the elevator head 13.
After being transferred until the upper predetermined position, that is, the center of the film _A''1 coincides with the center of the elevator head 13, it stops and enters a standby state.

The film feeding device consisting of clip groups 7, 7' and rubber belts 6d, 6'd is located at a height between the wrapping position 9 and the lower end position of the elevator head 13 as shown in FIG. As shown, they are arranged to face each other so as to sandwich the packaging section 9 when viewed from above.

The film feeding device will be explained below with reference to FIGS. 1 and 2.

A pair of adjuster screws 1 and 2 are rotatably provided on the machine frame 10 from the front side 10b to the back side 10c, and a hypoid gear 1c is attached to the end of each adjuster screw 1 and 2 on the side of the back side 10c. 2c are provided respectively.

Further, a rotating shaft 3 is disposed along the back surface 10c of the machine frame 10, and the hypoid gears 1c,
Hypoid gears 3a and 3b meshing with gear 2c are each fixed.

A handle 3c is provided at the right end of the rotating shaft 3 on the outside of the machine frame 10, and by rotating the handle 3c, the adjusting screws 1 and 2 can be rotated via the rotating shaft 3. .

The adjusting screw 1 has threaded portions 1a, 1b,
The adjusting screw 2 is formed with threaded parts 2a and 2b, respectively, and the threaded parts 1a and 2b shown in the upper part of FIG.
2a has a close pitch, and the lower threaded portions 1b and 2b have reverse threads and a coarse pitch. As a result, as will be described later, when the distance between the chain conveyors 6 and 6' is changed in accordance with the width of the stretch film used, the amount of movement of the chain conveyor 6 is smaller than that of the chain conveyor 6'.

This is because the direction in which the packaged items are carried out is taken into consideration. That is, in this embodiment, after completing the left and right horizontal folding and front folding of the packaged item, when carrying out the packaged item in the opposite direction to the carry-in direction, the package is folded backward to complete the packaging. This is because drastically changing the amount causes twitching, wrinkles, etc., which is not desirable. Moreover, the threaded portion 1a,
1b has a generally coarser pitch than threaded portions 2a and 2b.

In the figure, D is the distance between the centers of the packaging section 9, d is the distance on the adjusting screw 2 side, and C is the stretching rate of the film (hereinafter referred to as pre-stretch degree). The degree of pre-stretching C at the center is C=D-d/d. In order to keep this pre-stretch degree C constant regardless of the film width, it is necessary to change the widening angle of the chain conveyors 6, 6' in accordance with the film width.
The pitches of a and 2b are set to satisfy these.

In the apparatus of the embodiment, the degree of pre-stretching C at the center of the packaging section 9 is approximately 0.05 (5%).

Each screw portion 1 of the adjusting screw 1, 2
A, 1b, 2a, 2b are equipped with adjusting blocks 4a, 4b, 5a, which are fitted with nuts.
5b is arranged. A chain conveyor 6 is disposed across the adjusting blocks 4a, 5a on the back side 10c, and a chain conveyor 6' is disposed across the adjusting blocks 4b, 5b on the front side 10b.

In the figure, assuming that the axis passing through the center of the elevator head 13 from left to right is the X-X' axis, and the axis passing through the vertical direction is the Y-Y' axis, the chain conveyors 6, 6' are arranged in the film transport direction with respect to the X-X' axis. It is arranged in a wide-end shape. Furthermore, the chain conveyors 6 and 6' have substantially symmetrical structures, and the chain conveyor 6 will be explained in detail below.

As shown in FIG. 2, a mounting instruction member 50 is rotatably provided on the adjusting block 4a, and its rotation range is regulated by an engagement pin 51. The adjustment block 5a has a mounting instruction member 5.
2 is provided to be rotatable and movable within a small range in the front-rear direction, and its rotation range and movement range are limited to the engagement pin 5.
3. With this configuration, it is possible to change the divergence angle of the chain conveyor 6.

A mounting board 54 is mounted and fixed to the mounting members 50, 52 by a plurality of screws 54a, 54a, . . . . Sprockets 6a and 6b are rotatably disposed at each end of the mounting board 54, and an endless chain 6c is connected between the sprockets 6a and 6b.
is being strung up.

An endless rubber belt 6d with a circular cross section is provided around the outer periphery of the chain 6c. As shown in detail in FIGS. 7 to 10, a plurality of substantially U-shaped mounting plates 7a, 7a, . . . are provided at predetermined intervals on the side surface of the chain 6c on the back surface 10c side.

The mounting plates 7a, 7a... each pass through each connecting bush of the chain 6c, and hexagonal socket bolts 7b, 7b...
A clip 7 is rotatably attached to each mounting plate 7a via a shaft 7c.

The clip 7 has a lever shape that swings around a mounting portion 7e formed in the center. Clip 7
A semicircular recess 7d that fits into the rubber belt 6d is formed on the rubber belt 6d side, and the other end is used as an operating piece 7f for opening and closing the clip 7.
It acts as.

As shown in FIG. 10, a support plate 55 is attached over a predetermined area to the upper part of the mounting base plate 54 by screws 56. A protrusion 55a formed integrally with this support plate 55 fits into a central recess of the chain 6c to guide and support it, and another protrusion 55b engages with an engaging hook 7g formed integrally with the mounting plate 7a to guide and support the mounting plate 7a.

Next, a mechanism for opening and closing the clip 7 will be explained. The state in which the clip 7 and the rubber belt 6d are in contact as shown by the solid line in FIG. 10 is called the closed state, and the state in which the clip 7 and the rubber belt 6d are separated as shown in the dashed line is called the open state.

The opening/closing mechanism of the clip 7 includes a fixed guide member 8a,
8b and movable guide members 21, 22, and 23.

Fixed guide members 8a and 8b are disposed near the outside of the sprocket 6b on the film supply section side, and are configured to sandwich the side end portion of the film _A'1 .

The clip 7 moves under the chain 6c in a substantially closed state by balance and reaches the fixed guide member 8a.

The fixed guide member 8a is used to turn the clip 7 over the chain 6c in an open state, and as shown in FIG. 8, its lower left end portion engages with the operating piece 7f of the clip 7. It is formed into a smooth inclined surface to guide this.

As shown in FIG. 1, three movable guide members 21, 22, and 23 are arranged near the outside of the chain conveyor 6, one on the left side, one in the center, and one on the right side. Each movable guide member 21, 22, 23 has a substantially similar structure, and the movable guide member 22 in the center will be explained.

As shown in FIG. 11, the movable guide member 22 includes an upper pressing plate 22a and a lower pressing plate 22b.
The upper pressing plate 22a is configured to be substantially continuous with the lower pressing plates 21b and 23b of No. 3, and the upper pressing plate 22a is configured to be slightly shorter than the lower pressing plate 22b.

The lower side of the upper pressing plate 22a is fixed to the side of the lower pressing plate 22b by spot welding or the like, and the operating piece 7f of the clip 7 is placed in the space 22c formed by the upper pressing plate 22a and the lower pressing plate 22b. You will be guided.

The lower pressing plate 22b has elastic members 22d and 22'd, such as springs, disposed below near both ends thereof, and is always urged upward.

As shown in FIG. 10, the lower pressing plate 22b is formed into a U-shape in cross section, and this side surface is connected to the pin 22.
It is connected to the tip of the operating rod 22f of the solenoid S by e. The solenoid S is arranged approximately at the center of the lower pressing plate 22b and is screwed to the side plate 58.

When the solenoid S is not energized, the operating rod 22f is in a slidable state, and the lower pressing plate 22b is urged upward by the elastic members 22d and 22'd, as shown by the solid line in FIG. . Therefore, the operating piece 7f of the clip 7 is pressed upward by the lower pressing plate 22b. Therefore, the recess 7 of the clip 7
d is fitted with the rubber belt 6a to firmly hold the side edge of the film _A'1 .

When the solenoid S is energized, the operating rod 22f is attracted by the solenoid S and moves downward, as shown by the dashed line in FIG. 10, and the upper pressing plate 22a moves downward.

The actuating piece 7f in the space 22c is the upper pressing plate 22a.
The clip 7 is pushed down and moved downward, and the clip 7 becomes open.

Incidentally, the upper pressing plate 22a of the guide member 22 may be omitted; in that case, when the lower pressing plate 22b is lowered by the excitation of the solenoid S, the clip 7 will no longer be affected by the force, and the clip 7 will be held by the strong force of the film. deviate from

Next, the drive mechanism of the chain conveyor 6 will be explained.

As shown in FIGS. 1 and 2, a gear 24 is coaxially fixed to the sprocket 6a on the opposite side from the film supply section, and a drive shaft 25 is disposed parallel to the adjusting screw 1. A gear 26 that meshes with the gear 24 is provided on the shaft 25.

The gear 26 is a key groove 25a formed on the drive shaft 25.
It is supported by the adjusting block 4a of the chain conveyor 6 so as to be slidable along the chain conveyor 6 in accordance with the width of the film. The drive shaft 25 includes a chain 25b, bevel gears 25c, 25d, and a chain 25.
e, the motor via a transmission mechanism such as a reducer 25f.
The driving force of _M2 is transmitted.

Even when the chain conveyor 6 is moved by the mechanism described above, the driving force of the drive shaft 25 is transmitted to the sprocket 6a via the gears 26 and 24.

By transmitting the driving force of the motor _M1 to the drive shaft 25 via an electromagnetic clutch instead of the motor _M2 , the chain conveyor 6 can be driven independently of the vertical movement of the elevator head 13. I can do it. By doing so, the driving source can be used also.

Front feed devices 60, 60' are provided near the inner sides of the chain conveyors 6, 6' on the supply side via mounting fittings 59, 59', respectively. Note that the front feeding devices 60 and 60' have a substantially symmetrical structure, and the front feeding device 60 will be explained.

The forward feeding device 60 feeds out the film forward to a position where the film is held between the clip 7 of the chain conveyor 6 and the rubber belt 6a, and includes upper and lower feeding belts 27 and 28. As shown in FIG. 10, three sets of lower feed-out belts 28 are arranged at predetermined intervals, with two adjacent belts forming one set. Upper feeding belt 27
A total of three belts are disposed so as to abut on the center recess of each pair of feed belts 28, 28.

As shown in FIG.
are stretched between pulleys 27a and 27b of the same diameter, and the lower feeding belt 28 is connected to a large diameter roller 28.
a and the small diameter roller 28b.

The front large-diameter roller 28a has a drive shaft 6 with a hexagonal cross section.
1, and the drive shaft 61 has a first
As shown in the figure, the driving force of a motor (not shown) is transmitted through a chain 62.

As shown in FIG. 2, the large diameter roller 28a is connected to a film support roller 20' via a belt 30, and rotates the support roller 20'. Further, the support rollers 21' are also linked via a belt (not shown) so that they rotate in synchronization.

The support rollers 20', 21' are made of metal such as aluminum with good conductivity, and at least their surfaces are grounded. Stretch film is highly insulating and thin, and is also highly susceptible to charging due to friction as it is pulled from the film roll. This is because if this electrification is not prevented or regulated, ICs, LSIs, etc. that make up the control circuit may malfunction due to the influence of the electrostatic nozzle. If it is insufficient to ground only one side of the stretch film, a separate grounding roller may be provided to ground both sides.

The forward feeding device 60 holds the film A' ₁ between the upper and lower feeding belts 27 and 28, and drives the lower feeding belt 28 to feed the film A' ₁ forward.

The forward feeding speed of the forward feeding device 60 is set to be slightly slower than the feeding speed of the chain conveyor 6. By doing so, the stretch film _A'1 can be pre-stretched in the Y-Y axis direction.

In FIG. 1, 29 and 29' are cutter devices, which are provided on the chain conveyors 6 and 6', respectively. Each of the cutter devices 29, 29' is provided with a sliding member having a saw blade-shaped top on the opposing side, and this sliding member is configured to be moved up and down by a driving means 29a shown in FIG. be done. When this sliding member slides upward, the film is cut.

Next, the operation of the apparatus of the embodiment will be explained.

First, select the film roll A ₁ that matches the material to be packaged from among the film rolls A 1 and A ₂ , and rotate _the handle 3c to widen the ends of the chain conveyors 6 and 6' according to the width of the film roll A _1. Adjust corners and spacing. That is, by rotating the handle 3c clockwise, the hypoid gears 1c,
Adjusting screws 1, 2 are rotated via 2c, 3a, 3b, and the distance between chain conveyors 6, 6' is widened, and by rotating counterclockwise, the distance is narrowed.

After the adjustment is completed, as shown in FIG. 2, it is fed out via a support roller 20' and an end detection roller 40, and its leading end is held between feeding belts 27 and 28 and between 27' and 28'. Large diameter roller 28
Rotate the stretch film A′ ₁ manually.
The blade is fed forward until the tip of the blade is directly above the cutter device 29, 29'.

In the above state, the preparation is completed and the packaging machine is ready for use. The packaging process will be explained below. In the packaging machine of the embodiment, the elevator head 13
If the vertical movement of the roller is one cycle, one article is wrapped in two cycles. However, for convenience of explanation, it will be explained here that packaging of one article is completed in one cycle, but the present invention is not limited in any way in this regard.

First, an operator places an object to be packaged on the pusher conveyor 12. Whether or not an object has been placed on the pusher conveyor 12 is determined by the weighing stability signal if the pusher conveyor 12 has a built-in measuring device, or by a micro switch, etc. if a measuring device is not built into the pusher conveyor 12. The device is informed by the sensor. As a result, the pusher conveyor 12 and the belt conveyor 14 are driven, and the conveyance of the packaged items is started.

The stretch film _A'1 is then fed out and transferred in parallel with the conveyance of the article to be packaged.

The length of the stretch film required for packaging, that is, the amount of film feeding out, can be set manually in advance using a setting dial (not shown) on the operation panel, or it can be set manually in advance using a setting dial (not shown) on the operation panel, or it can be set manually in advance using a setting dial (not shown) on the operation panel, or it can be set manually using a setting dial (not shown) on the operation panel, or it can be set manually in advance using a setting dial (not shown) on the operation panel. It is determined by detecting the The film is fed out by driving feed belts 28, 28' and support rollers 20' below the chain conveyors 6, 6'.
Support roller 20' and feeding belt 27,2
Film fed out by 7', 28, 28'
A' ₁ is the end of the belt 27, 27', 28, 28' on the end of feeding, and the both ends thereof are connected to the clips 7, 7' of the chain conveyor 6, 6' and the rubber belt 6d,
6'd, and are further fed out as the chain conveyors 6, 6' move. At this time, as described above, the belts 28, 2
Since the conveyance speed of the chain conveyors 6, 6' is set to be a little faster (approximately 5%) than that of the film A _' It is pre-stretched by about 5%.

Furthermore, since the chain conveyors 6, 6' are disposed in a widening manner as described above, the material is finally pre-stretched by about 5% at its central portion as it is fed out and transferred by the chain conveyors 6, 6'. When the chain conveyors 6, 6' have finished feeding out the film _A'1 of a predetermined length, the feeding belts 28, 28' are stopped, and the cutter devices 29, 29' are driven to remove the film A'1 necessary for packaging. The cut film A″ ₁ is then transported until its center is located on the Y-Y axis of the central part of the apparatus, and then transferred to the chain conveyor 6, 6' _. drive is stopped. In this state, the film _A''1 is held under the packaging section 9 and above the elevator head 13 in a wrinkle-free and stretched state.

After the transfer of the film _A''1 and the loading of the object to be packaged onto the elevator head 13 are completed, the elevator head 13 starts to rise.As a result, the object to be packaged pushes up the film _A''1 on the way. Its upper surface is covered with a film _A''1 and reaches the packaging section 9.

In this packaging section 9, horizontal folding plates 17, 17'
The left and right horizontal folds are performed. In addition, in the process of horizontal folding, the left and right movable guide members 21,
21', 23, 23' are driven, and the film _A''1 is held on the left and right by the clips 7, 7' and the rubber belts 6d, 6'd that engage with these guide members 21, 21', 23, 23'. It will be released.

Immediately before or after the end of the left and right folding, front folding is performed by the front folding plate 16. In this pre-folding process, the central movable guide member 22' of the chain conveyor 6' on the front side 10b is driven, and the clip 7' and rubber belt 6'd that engage with this guide member 22' fold the film _A''1. The grip at the front center part is released. After the front folding is completed, the pusher 31 carries out the packaged object onto the heat belt 19, and during this carrying out, the rear folding roller 18 carries out the rear folding.
After this, during the folding process, the rear chain conveyor 6
The center guide member 22 of is driven, and the rear central portion of the film A″ ₁ is released from being held by the clip 7 engaged with the guide member 22 and the rubber belt 6d. Upon completion of carrying out onto the heat belt 19,
The above-mentioned post-folding is completed, and the packaging is completed. After the packaging is completed, the folded portion at the bottom of the packaged item is thermally welded while being transferred by the heat belt 19, and the packaging is completed. After completing the above front folding, elevator head 1
3 begins to descend, and after the elevator head 13 returns to the lower position and the packaged object is transferred onto the heat belt 19, the apparatus enters a standby state. Incidentally, if the next item to be packaged has already been placed on the pusher conveyor 12 during the above packaging process, the above operation can be repeated.

As described above, in the embodiment, the front feeding device 6
0,60' feeding belt 27, 28, 27', 2
8' constitutes the first feeding device of the present invention to feed the film A' ₁ from the film roll A ₁ ;
The chain conveyors 6 and 6' constitute the second feeding device of the present invention, and stretch the film A' ₁ in the transfer direction and the width direction during feeding, and when the feeding and transfer direction is completed, the stretching in both directions is completed. state.

Incidentally, in place of the above embodiment, the roller 40 is used in the present invention.
The roll is turned into a film roll by applying rotational power to
The first feeding device pulls out the film from A ₁ , and feeding belts 27, 28, 27', 2
8' and chain conveyors 6, 6' constitute a second feeding device, and the transfer speed is adjusted between the feeding belts 27, 28, 27', 28' of the second feeding device and the rollers 40 of the first feeding device. It is also possible to provide a difference so that the film is stretched in the transport direction.

Further, in the above embodiment, when the interval between the film feeding and transferring devices 6, 6' is adjusted according to the width of the film to be used, by changing the divergence angle corresponding to the interval, films of different widths can be processed. We have devised a way to ensure that the degree of expansion is approximately the same even when using This is because the width of the film used differs significantly (for example, the film above
A ₁ width is 200mm, film roll A ₂ width is 400mm)
Although this is because the above points are taken into consideration, the configuration is not limited to this configuration due to the above-mentioned reasons. For example, if the divergence angle can be kept constant even when the distance is changed, the distance adjustment mechanism of the film feeding and transferring device can have a relatively simple structure.

The structure of the film feeding and transferring device is not limited to the above-mentioned embodiment, but may be of any type as long as it can feed and transfer the film by pinching the ends of the film.

Alternatively, the clip 7 may release the film by moving the operating rod 22f of the solenoid S upward depending on the position of the shaft 7c of the clip 7 and the operating piece 7f.

(Effects) According to the present invention, both edges in the width direction of the film are firmly held by the chain, the elastic belt, the clip, and the three-divided guide member that operates the clip, which constitute the film feeding and transporting mechanism. When the film is folded by the film folding mechanism, there is no need for a means for pressing and holding the film separately from the feeding mechanism. In other words, the transfer mechanism also serves as the film holding mechanism of the film holding device, and the film holding mechanism and its release are not required. The structure of the film holding device consisting of a mechanism can be simplified.

The solenoid is energized to move the guide member downward and release the clip from holding the film, so the solenoid is only energized for a short period of time when the film is released, reducing the risk of solenoid seizure or other failures. It can improve durability and eliminate the need to use expensive solenoids with anti-seizure function, and especially has a three-part structure and many solenoids (at least 6).
This method is effective in reducing costs in the device of the present invention using the method.

Therefore, each guide member of the clip holding the film is synchronized with the activation timing of the folding plate, and the film is released by energizing the solenoid of each guide member, resulting in a good packaging finish and low cost. We can provide packaging machines.

[Brief explanation of the drawing]

Figure 1 is a plan view showing the structure of the main parts of a stretch film packaging machine embodying the present invention, Figure 2 is a vertical cross-sectional side view of the same, and Figures 3 to 5 are stretch film packaging machines embodying the present invention. A drawing showing the outline of the machine.
3 is a vertical side view, FIG. 4 is a sectional view of the same, FIG. 5 is a front view of the same, FIG. 6 is a plan view showing the structure of the film front feeding device, and FIGS. 7 to 10 are The structure of the film feed-out transfer device is shown in drawings, and FIG. 7 is a top view of its main parts, FIG. 8 is a top view of the same, FIG. 9 is a side view of the same, FIG. 10 is a front view of the same, and FIG. 11 is a movable guide. FIG. 3 is a side view of main parts showing the structure of the member. In the figure, 1 and 2 are adjast screws, 6 and 6'
is a chain conveyor, 6d and 6'd are rubber belts,
7, 7' are clips, 21, 21', 22, 22',
23 and 23' are movable guide members, and A ₁ and A ₂ are stretch film rolls.

Claims (1)

[Scope of utility model registration request] A stretch film packaging machine having a film transfer path for feeding a strip-shaped stretch film to a packaging section, and the wrapping section having a folding mechanism for folding the stretched film into an object to be packaged,
A pair of endless chains are rotatably disposed on both sides of the film transfer path, an endless elastic belt is provided around the outer periphery of each chain, and the center portion is pivotally supported on the outer surface of each chain. A plurality of swingable clips are attached, and a guide member divided into three along the direction of movement of each chain is arranged outside the packaging portion of each chain, and each clip has one end attached to the elastic belt. The clip has a portion that can be fitted with the side edge of the stretch film to clamp the side edge of the stretch film, and the other end is provided with an actuating piece that is engaged and guided by the guide member, and each guide member has an actuating piece that is directly or indirectly connected to the actuating piece of the clip. An elastic member is provided to clamp the film, and is connected to a solenoid that is excited in synchronization with the timing of the film folding operation of the folding mechanism to move the guide member and release the clip from holding the film. film holding device.