JP2000085723A - End seal device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the preliminary heating by one end seal device, and to surely effect the heat seal of various films. SOLUTION: In an end seal device provided with end sealers 12, 12' on a pair of rotary shafts 10, the end sealers are fitted to the rotary shafts in a reciprocating manner in the direction going away from their center (the movement is ensured by a guide rod 16 and a bearing 18). The end sealers are prevented from being moved in the direction going away from the rotary shafts by a stopper 20 provided on the rotary shafts, and the end sealers are prevented from being moved in the direction close to the rotary shafts by bringing the end sealers into direct contact with the rotary shafts. In addition, a coil spring 22 is provided between the end sealers and the rotary shafts so as to urge the end sealers in the direction going away from the rotary shafts by the elastic restoring force of the coil spring.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an end seal device.

[0002]

2. Description of the Related Art In an automatic packaging machine or a bag making apparatus, an end seal device is arranged on the carry-out side to seal and cut a tubular film formed in a direction transverse to a traveling direction. Manufactures bodies (empty bags).

[0003] As one type of the end seal device, there is a rotary end seal device. In this type, as shown in FIG. 1, end sealers 3 are respectively attached to rotating shafts 2 which are arranged above and below a conveyed film 1 so as to face each other. At this time, the peripheral surface of the end of the end sealer 3 which meshes with each other becomes the sealer surface 3a, and the end sealers 3 arranged vertically are arranged.
Are brought into contact with each other to sandwich the film 1. Further, since a heater is built in the end sealer 3, the film 1 is heated and melted by sandwiching the film 1, and thereby, the film 1 is thermally fused and sealed. further,
A cutter blade 4 and a receiving blade 5 are built in opposing surfaces of both end sealers 3, and the film 1 is simultaneously cut in the horizontal direction by sandwiching the film between the cutter blade 4 and the receiving blade 5. .

The center of rotation of each end sealer 3, that is, the distance r (which is the radius of rotation) from the center of the rotary shaft 2 to the end of the end sealer 3 matches the radius of curvature of the sealer surface 3a of the end sealer 3. (A)
→ As shown in (b) → (c), the contact is smoothly made in order from the front in the rotation direction with the rotation.

[0005]

However, the above-mentioned conventional end seal device has the following problems. That is, the end sealer is fixed to the rotating shaft and rotates integrally, and furthermore, the turning radius of the end sealer and
Since the curvature radii of the sealer surfaces match each other, the sealer surfaces 3a of both end sealers 3 come into contact with each other at the lowermost position (uppermost end), as shown in the drawing, on the line connecting the rotation centers. It becomes Y.

[0006] Therefore, the film 1 is the end sealer 3
The part of the film that comes into contact with the (sealer surface 3a) is also located on the line connecting the rotation centers. Then, the moving speed of the film 1 and the sealer surface 3a of the end sealer 3
Since the moving speeds at the positions are the same, each part along the traveling direction of the film 1 is heat-sealed by linear contact with both sealer surfaces 3a when moving on the line connecting the rotation centers. Become.

In other words, focusing on each of the film portions to be heat-sealed, the time of contact with the sealer surface, the heating temperature, and the pressure are constant. Depending on the material of the film, it may be necessary to heat the film firmly in order to securely seal it. In such a case, it is possible to cope with this by increasing the time of contact with the sealer surface. But,
If the contact time is simply lengthened in such a manner, the number of products manufactured per unit time is reduced, which is not preferable.

It is also conceivable to provide a sealer for residual heat on the upstream side of the end seal device, but it is not preferable because the size of the device is increased. Furthermore, the heating temperature cannot be simply increased because there is a temperature suitable for the film. Furthermore, it is structurally difficult to increase the pressing force.

[0009] Of the film parts to be heat-sealed, the part to be sealed first is not sufficiently preheated because the end sealer is suddenly brought into contact therewith, so that the above-mentioned problem occurs more remarkably.

SUMMARY OF THE INVENTION The present invention has been made in view of the above background, and has as its object to solve the above-mentioned problems, to enable preheating with a single end sealing device, and to provide various types of films. An object of the present invention is to provide an end seal device capable of reliably performing heat sealing on the end seal device.

[0011]

To achieve the above object, an end seal device according to the present invention comprises an end seal device having a pair of rotary shafts and end sealers respectively connected to the rotary shafts. , An end sealer attached to at least one of the pair of rotating shafts is attached to the rotating shaft so as to be reciprocally movable away from the center thereof. The end sealer is prevented from moving in a direction away from the rotation shaft by a stopper provided on the rotation shaft, and the rotation shaft and the end sealer come into direct or indirect contact with each other, so that the end sealer rotates. Movement in the direction approaching the axis is prevented. Further, an elastic member (in the embodiment, realized by the "coil spring 22") is provided between the end sealer and the rotation shaft, but may be a leaf spring or another spring member, or rubber or the like. The end sealer may be urged in a direction away from the rotation shaft by an elastic restoring force of the elastic member (claim 1).

With this configuration, when no load is applied, that is, when the pair of end sealers are not in contact with each other, the end sealer protrudes in a direction away from the rotation shaft by the urging force of the elastic member. Therefore, the sealer surface on the front side in the rotation direction can contact and hold the film quickly. When the end sealer is rotated as it is, the end sealer moves toward the center of the rotation shaft, so that the state in which the film is held can be maintained. Therefore, since the film portion can be heated for a longer time than usual, the film portion is preheated, and then the end sealer contacts the rotating shaft and receives a desired reaction force to pressurize and heat the preheated film portion. Sealed. Further, the downstream portion of the film portion reliably heat-sealed in this manner is heat-sealed while being in line contact with the end sealer as in the related art. At this time, since the portion immediately before the portion to be heat-sealed by the line contact is already heated, the heat at that time is transmitted and preheated. Therefore, heat sealing is ensured.

[0013]

FIG. 2 shows a preferred embodiment of an end seal device according to the present invention. As shown in FIG. 1, a pair of end sealers 12 and 12 are attached to opposite sides of a prismatic rotating shaft 10. By doing so, the seal is cut once every time the rotating shaft 10 rotates 180 degrees. Of course, one rotating shaft 1
One end sealer may be provided for 0, or three or more end sealers may be provided.

The rotating shaft 10 and the end sealer 12 shown in FIG. 2 are installed on the upper side with the film 13 interposed therebetween. , End sealer 12 '. This is the same as the conventional case.

Although not shown, the end sealer 1 is not shown.
A heater is built in each of the end sealers 12, 1 ', and the heaters are energized and overheated.
The entire 2 'is heated, and the sealer surface 12a is set at a predetermined temperature. In the center of the end sealer 12, a cutter blade 14 is attached. The tip of the cutter blade 14 is sharp and protrudes outward by a predetermined amount from the sealer surface 12a. Further, a receiving blade 15 for cutting the film 13 in contact with the cutter blade 14 is provided in the lower end sealer 12 ′.
The tip of the receiving blade 15 is a flat surface. And
When both end sealers 12 and 12 'are engaged with each other, the film 13 is taught and cut by the cutter blade 14 and the receiving blade 15. Note that each of the above-described basic configurations is the same as the conventional configuration, and a detailed description thereof will be omitted.

Here, in the present invention, the end sealer 12,
12 'is attached to the rotating shaft 10 so as to be able to move forward and backward from the center to the outside (hereinafter, since this configuration is the same for the upper and lower end sealers 12, 12', the illustrated upper end sealer 12 It will be described based on.)

Specifically, a guide rod 16 is attached to a side wall of the end sealer 12, and the guide rod 16 is inserted into a bearing 18 attached to a side surface of the rotating shaft 10.
Thus, the guide rod 16 can stably reciprocate along the axial direction.

The side wall of the end sealer 12 opposite to the guide rod 16 has a base end side (sealer surface 12a).
(Opposite side to the above) is defined as a protruding portion 19 protruding one step outside. Then, a stopper 20 is provided so as to cover the outside of the protrusion 19. The base end side of the stopper 20 is attached to the rotating shaft 10. Further, the stopper 20
Is bent toward the end sealer 12 side, and the front end portion 20a and the front end surface 19 of the protruding portion 19 are bent.
a can be contacted. However, since the stopper 20 is longer, the end sealer 12 reciprocates by the difference in the length, and when the end sealer 12 moves to the distal end side, the distal end surface 19a of the projection 19 and the distal end 20a of the stopper 20 are moved.
To prevent the end sealer 12 from moving away from the rotating shaft 10 any more. Further, when the end sealer 12 moves in a direction approaching the rotation shaft 10, the base end surface of the end sealer 12 contacts the rotation shaft 10 and prevents further approach movement. .

Further, the end sealer 12 of the rotating shaft 10
A concave portion 10a is provided on the surface facing the above, and a coil spring 22 is inserted into the concave portion 10a. Due to the elastic restoring force of the coil spring 22, the end sealer 12
Is always urged in a direction away from the rotating shaft 10. As a result, the end sealer 12, which is normally upward (shown enlarged in FIG. 3) in FIG. 2, is separated from the rotating shaft 10 and projects outward.

From this state, in order to hold the film 13,
When it comes into contact with the end sealer 12 ′ attached to the lower rotating shaft, the spring 22 is compressed by the reaction force as shown in an enlarged view in FIG. 4, and the end sealer 12 comes into contact with the rotating shaft 10. The contact between the rotating shaft 10 and the end sealer 12 in this manner causes the both end sealers 1
The film can be held at a predetermined pressure between the films 2 and 12 '.

The spring 22 only needs to have an elastic restoring force enough to protrude the end sealer 12 outward without load. 2 to 4, a circle shown by a two-dot chain line is a rotation trajectory of the end (the sealer surface 12 a) of the end sealer 12 when the end sealer 12 is rotated in contact with the rotating shaft 10. This indicates that the tip of the end sealer 12 normally projects outward with respect to the rotation trajectory. In other words, this rotation locus is the rotation locus of the sealer surface in the conventional end seal device.

Also in this embodiment, the sealer surface 12
The radius of curvature of a is equal to the radius of the circle indicated by the two-dot chain line. That is, a pair of upper and lower end sealers 12, 1
2 'coincides with the radius of rotation when in contact. Thus, when both end sealers 12 and 12 'are rotating while contacting each other, both sealer surfaces 1 and 12' are kept in a conventional manner.
The contact positions of 2a and 12a 'are moved while making line contact.

With the above configuration, when the end sealer is fixed to the rotary shaft, the pair of end sealers contact for the first time on the line connecting the centers of the rotary shafts as described with reference to FIG. In this embodiment, since the end sealers 12 and 12 'protrude outward as described above, as shown by the symbol X in FIG. 1, the end sealers 12 and 12' can come into contact with the film from an earlier position on the downstream side than on the line, and as it is. By continuing the rotation, the end sealers 12 and 12 'gradually move closer to the rotating shaft 10 while holding the same film portion.

Accordingly, unlike the other portions, the film portion held first at this time has a preheating effect by being held and heated for a relatively long period of time, and then exerts a preheating effect, and thereafter, on a line connecting the center of the rotating shaft. By being firmly pressed from both end sealers when
Heat sealed reliably.

Since the subsequent film portion is heat-sealed while being in line contact as in the past, the heating time does not become as long as the above-mentioned first contact portion.
Since the film portion in the front in the traveling direction has already been heated, a preheating effect by the heating is expected, so that the heat sealing can also be performed.

In the above-described embodiment, the end sealers attached to the upper and lower rotating shafts can both move toward and away from the rotating shaft. However, the present invention is not limited to this, and at least one of the end sealers can be moved. It should be possible. Also, it has been described that the rotation axis is arranged vertically because the film is used in a device for moving the film in the horizontal direction. However, in the case of a device in which the film is moved in the vertical direction, the rotation axis is arranged in the horizontal direction with the film interposed therebetween. It goes without saying.

[0027]

As described above, in the end seal device according to the present invention, since the end sealer can approach and separate from the rotating shaft, the sealer surface on the front side in the rotating direction is:
Since the film comes into contact with the film quickly and then continues to be sandwiched for a certain period of time, the sandwiched film portion can be sufficiently preheated and can be reliably heat-sealed. That is, the preheating can be performed by one end sealing device, and the various films can be reliably heat sealed.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an example of a conventional end seal device.

FIG. 2 is a view showing a preferred embodiment of an end seal device according to the present invention.

FIG. 3 is an enlarged view of a main part thereof.

FIG. 4 is an enlarged view of a main part thereof.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Rotating shaft 10a Concave part 12, 12 'End sealer 12a, 12a' Sealer surface 14 Cutter blade 15 Receiving blade 16 Guide rod 18 Bearing 19 Projection part 20 Stopper 22 Spring

Claims (1)

[Claims] 1. An end seal device comprising a pair of rotating shafts and end sealers respectively connected to the rotating shafts, wherein an end sealer attached to at least one of the pair of rotating shafts is provided with respect to the rotating shafts. The end sealer is prevented from moving in a direction away from the rotation shaft by a stopper provided on the rotation shaft, and the rotation shaft and the end sealer are directly or indirectly mounted. The end sealer is configured to be prevented from moving in the direction approaching the rotation shaft by contacting the rotation shaft. Further, an elastic member is provided between the end sealer and the rotation shaft, and the elastic member is elastically restored. The end sealer is urged in a direction away from the rotation axis by a force. Le devices.