Film feeding apparatus

A novel apparatus is provided for feeding a packaging film with registered marks to a working machine, such as a packaging machine which packs products in wraps. According to the apparatus, rapid and continuous feeding of the film is realized. Further, one operator can watch and control a plurality of machines.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to an apparatus for feeding a packaging film with 
registered marks to a working machine, such as a packaging machine which 
packs products in wraps. 
2. Description of the Prior Art 
In a conventional film feeding apparatus having a main roll for feeding a 
first film to a packaging machine, when the first film on the main roll is 
consumed, the main roll must be exchanged for auxiliary roll and the 
latter must be reset. However, the exchange of the main roll for the 
auxiliary roll and the reset of the auxiliary roll are troublesome 
operations. In a known film feeding apparatus having a main roll of a 
first film and an auxiliary roll of a second film, the front end of the 
second film is manually connected to the terminal end of the first film. 
However, in connecting the first film to the second film, registered marks 
or patterns on the first and second films must be carefully registered 
with each other. Such registration operation is rather troublesome. 
Furthermore, in the prior art as mentioned above, when the first film is 
exchanged for the second film, or when the second film is connected to the 
first film, the film feeding machine must be stopped, resulting in a 
decrease of a working efficiency of the packaging machine to which the 
film is fed, and in a decrease of a productivity. In addition to the 
foregoing, an operator must continuously watch the end of the first film 
and the charging of the second film in the feeding machine exclusively 
needs at least one operator. 
SUMMARY OF THE INVENTION 
The primary object of the present invention is, therefore, to eliminate the 
above mentioned drawbacks of the prior art, by providing a film feeding 
apparatus in which the film can be rapidly charged so as to continuously 
feed the film, thereby to increase the working efficiency and the 
productivity of the machine to which the film is to be fed, and to enable 
only one operator to control a plurality of film feeding apparatuses. 
In order to achieve the aforementioned object, according to the present 
invention, there is provided a film feeding apparatus comprising a body 
which has a first film roll for feeding a first film with positioning 
registered marks and an auxiliary film roll for feeding a second film with 
positioning registered marks, for feeding the first film to a working 
machine such as a packaging machine, through a conveying path, wherein 
said apparatus comprises a first sensor on the conveying path for 
detecting the end of the first film and a second sensor on the conveying 
path for detecting the positioning registered marks of the first film that 
are located adjacent to the terminal end of the first film, a film holder 
for holding the beginning end of the second film, a film pressing member 
for pressing the first film against the second film, said film holder and 
said film pressing member being located on opposite sides of the conveying 
path so that the film pressing member comes away from and close to the 
film holder, the first positioning registered marks of the second film 
being spaced from the beginning end thereof at a predetermined distance, 
said beginning end of the second film being provided with an adhesive tape 
which is partially adhered thereto, a cutter located in the vicinity of 
the film holder for cutting the first film in order to separate the first 
film from the first film roll, and means for actuating said film holder 
and/or said film pressing member to cause them to come close to each other 
in order to connect the first film to the second film by means of the 
adhesive tape at the beginning end of the second film and for actuating 
the cutter to cut the first film, when the first sensor detects the end of 
the first film and then the second sensor detects the first positioning 
registered marks.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
In the drawings, a body 1 of the film feeding apparatus of the present 
invention is provided, on its side plates la, with roll supports 2 which 
rotatably support a main roll A1 which feeds a first film a.sub.1 and an 
auxiliary roll A2 which feeds a second, i.e. auxiliary film a.sub.2. On a 
rear surface 1b and a upper surface 1c, of the body 1 are provided 
rotatable guide rollers 11, 12, 13, 14, and 15 which form a conveying path 
of the first film a.sub.1. A first sensor S1, a film holder 3, and a 
cutter 4 are provided between the guide rollers 11 and 12. The first 
sensor S1 can be a light reflection type optical sensor which has light 
emitting and receiving elements (not shown) located on the opposite sides 
of the conveying path between the guide rollers 11 and 12. The first film 
a.sub.1 has an aluminum foil P1 applied to a terminal end thereof for 
indicating the end of the first film, as shown in FIG. 5, so that the 
first sensor S1 can detect the aluminum foil P1 to detect the end of the 
first film a.sub.1. 
The holder 3 has side plates 3a and pressing plates 3c which are located 
between the side plates 3a and which has an intermediate V-shaped channel 
3b which, in turn, has an elongated hole 3d having a length corresponding 
to the film width, and a leaf spring 3e for engaging the film, as can be 
seen from FIG. 3. The side plates 3a have mounting members 3f which hold a 
holding plate 3g therebetween. 
The second film a.sub.2 is cut at a terminal end spaced at a predetermined 
distance Lo from the leftmost (in FIG. 4) registered marks M which are 
provided in advance on the second film, as shown in FIG. 4. An adhesive 
tape P2 is applied to the cut terminal end of the second film, so that the 
adhesive tape P2 is adhered, at its one side end, to the holding plate 3g, 
and at its intermediate portion, to the front end of the second film 
a.sub.2. The opposite side end of the adhesive tape P2 is located on one 
of the pressing plates 3c. The adhesive surface of the adhesive tape P2 is 
spaced from and opposed to the first film a.sub.1. 
Rubber pressing plates 5 are mounted to leaf springs 8 which are mounted to 
a mounting member 7 secured to a piston rod of a pneumatic cylinder 6 and 
are opposed to the corresponding pressing plates 3c in such a way that the 
first film a.sub.1 extends between the corresponding rubber pressing 
plates 5 and the pressing plates 3c. Each of the leaf springs 8 is made of 
two leaves which are bent and interconnected into an elliptical shape, so 
that when the rubber pressing plates 5 are pressed against the 
corresponding pressing plates 3c through the first film a.sub.1 by means 
of the operation of the pneumatic cylinder 6, the elliptical leaf springs 
8 are deformed into a collapsed ellipse having a shorter minor axis and a 
longer major axis. When the elliptical leaf springs 8 are collapsed or 
deformed, the cutter 4 rigidly connected to the center portion of the 
mounting member 7 thrusts into the first film a.sub.1 and cut the same. 
The V-shaped channel 3b enables the cutter 4 to come therein. 
A second sensor S2, a drive roller 9 and a pressing roller 10 are arranged 
between the guide rollers 12 and 13 on the upper surface 1c of the body 1. 
The drive roller 9 is connected to and driven by a motor with an 
electromagnetic brake (not shown) so as to rotate at a constant speed. The 
pressing roller 10 is opposed to the drive roller 9, so that the first 
film a.sub.1 extends therebetween. The pressing roller 10 is connected to 
and actuated by a pneumatic cylinder 10a so as to move up and down. The 
pressing roller 10 moves downward in accordance with a detection signal of 
the first sensor S1 which detects the completion of the first film a.sub.1 
to feed the first film at a constant speed, with the help of the drive 
roller 9 which holds the first film between the drive roller 9 and the 
pressing roller 10. When the second sensor S2 detects the first registered 
marks M of the first film which now moves at a constant speed, a timer T 
(FIG. 2) which is connected to the second sensor S2 is made on. After 
preset time of the timer T lapses, the cutter 4 cuts the first film 
a.sub.1. The set time of the timer T can be properly selected in 
accordance with a distance L1 (FIG. 5) between the portion of the first 
film that is to be cut and the registered marks M, so as to prevent the 
connecting portion, i.e., the seam of the first film to the second film 
from coming into registration with a lateral seal portion which will be 
made later. The pressing roller 10 moves upward as soon as the first film 
a.sub.1 is cut by the cutter 4. 
The distance Lo between the front end and the first registered marks M, of 
the second film a.sub.2 is such that when the second film a.sub.2 is 
adhered to the first film a.sub.1, the distance L between the last 
registered marks M of the first film a.sub.1 and the first registered 
marks M of the second film a.sub.2 is identical to that of two adjacent 
registered marks of the first or second film, as shown in FIG. 6. The 
connection of the first and second films is effected when the second 
sensor S2 detects the first registered marks M subsequent to the detection 
of the end of the first film a.sub.1. In the illustrated embodiment, the 
working machine 20 is supposed to be a packaging machine for packing 
products into wraps which are formed by the film with registered marks. In 
such an embodiment, it is possible to provide tension rollers 16 and 17 
for controlling the tension of the film. Alternatively, it is also 
possible to provide the tension rollers 16, 17 on the film feeding 
apparatus of the present invention rather than on the working machine 20. 
The apparatus according to the present invention operates as follows. 
First, the front end of the second film a.sub.2 is formed as shown in FIG. 
4 and is held by the holder 3. 
When the first sensor S1 detects the aluminum foil P1 of the first film 
a.sub.1 at the end of the first film a.sub.1, the pressing roller 10 moves 
downward to feed the first film at a constant speed. After the feed of the 
first film at a constant speed starts, the second sensor S2 detects the 
first registered marks M to actuate the cylinder 6, so that the rubber 
pressing plates 5 cause the first film a.sub.1 to come into press contact 
with the pressing plates 3c with the help of the leaf springs 8. By the 
press contact of the first film against the pressing plates 3c, the first 
film is adhered to the adhesive tape P2 of the second film a.sub.2 through 
the upper rubber pressing plate 5 that is opposed to the front end of the 
second film a.sub.2. The first film a.sub.1 can be thus automatically 
connected to the second film a.sub.2. 
After a predetermined time lapses, the pneumatic cylinder 6 is further 
advanced to cut the first film, and is then returned to its initial 
position shown in FIG. 3. As a result of this, the second film a.sub.2 is 
continuously fed following the rear end of the first film a.sub.1, so that 
the feed of the auxiliary film, i.e. the second film can automatically be 
effected. After that, the first roll A1 is removed and-then the second 
roll A2 is moved to a first position where the first film was located and 
has been removed from. A new auxiliary film is put in a second position 
for the second roll which has been moved to the first position for the 
first roll A1. The front end of the auxiliary film, i.e. a new second film 
a.sub.2 is held by the holder 3, as shown in FIG. 3. 
As can be understood from the above discussion, according to the present 
invention, the auxiliary film can be automatically fed after the first 
film ends without stopping the operation of the machine, thus resulting in 
rapid and continuous feeding of the film. Furthermore, according to the 
present invention, one operator can watch and control a plurality of 
machines.