Field of the Invention:
The present invention relates to a high speed sealing method for making film or laminated packs or pouches on single or multi track machines.
Background of the invention:
In the present art, the process of sealing for making stick packs, sachets or pouches with heat sealable polymer film/laminate is done by using intermittent pulling and sealing mechanism in single track or multi track machines. This kind of sealing mechanism which starts, stops & then restarts at some intervals have some inherent disadvantages like limited process speed & more wear & tear of the parts with jerky operation.
The sealing process is a combination of temperature of two jaws, pressure between the two jaws on film or laminate & holding time. To increase the process speed, temperature can not be increased beyond a limit since it may burn the film or laminate. Similarly pressure beyond a limit can damage the film or laminate between the jaws. Holding time is necessary for sufficient heating of the pressed film or laminate to fuse for good seal.
In intermittent process the film or laminate travel time & hold time directly contribute to the total cycle time.
To overcome the above limitations in increasing the speed of the machine there is a need to modify the existing sealing mechanism to provide continuous movement of film or laminate but allowing pressing by jaws for sealing when required, during movement & also provide the desired holding time.
Object and summary of the invention :
To obviate the aforesaid drawbacks, the object of the instant invention to provide a high speed sealing method for making film or laminated packs or pouches on single or multi track Form Fill & Seal (FFS) machines.
It is another object of the present invention to provide a sealing method which increases the sealing hold time without increasing the total cycle time.
It is another object of the present invention to provide a sealing method where pouches or packs are formed individually or in continuous strip.
To achieve the aforementioned objectives, the present invention provides a high speed sealing method for making film or laminated packs or pouches on single or multi track machines. The said method comprises the steps of:
• continuous motion of the sealing jaws in their path through a set of gear drives.
• providing an eccentric motion to the sealing jaws brackets by gear drive shafts, through a set of levers attached with the shaft of one side gear drive and another set of levers attached with the shaft of other side gear drive
• keeping the front or the rear jaw longer or fixing one of said jaws forward by certain distance with respect to the other jaw such that when both the jaws move from top to bottom, they start pressing the film or laminate between them before the middle position till after the middle position in continuous motion, which increases the sealing hold time without increasing the total cycle time
• providing cushioning effect during sealing which also prevent damage to the film or laminated within the contact surfaces of the jaws by providing adjustable or fixed flexible force by a means on the back of either front or rear jaw or both the jaws.
In another aspect the present invention provides a high speed sealing method for making film or laminated packs or pouches on single or multi track machines, said method comprising the steps of:
• Continuous motion of the sealing jaws in their path through a set of gear drives
• Providing rotary motion to jaw brackets through a set of eccentric drive pins on the face of each gear drive shaft
• keeping the front or the rear jaw longer or fixing one of said jaws forward by certain distance with respect to the other jaw such that when both the jaws move from top to bottom, they start pressing the film or laminate between them before the middle position till after the middle position in continuous motion, which increases the sealing hold time without increasing the total cycle time
• Providing cushioning effect during sealing which also prevent damage to the film or laminated within the contact surfaces of the jaws by providing adjustable or fixed flexible force by a means on the back of either front or rear jaw or both the jaws.
Brief description of the accompanying drawings:
The features of this invention are set forth with particularly in the appended claims. The invention, together with its objects and advantages thereof may be best understood by reference to the following description taken in conjunction with the accompanying drawings, in which like reference numerals identify substantially like elements in the several figures and in which:
Figure 1 shows the isometric view of the sealing method according to the first embodiment of the present invention.
Figure 2 depicts the isometric view of the sealing method according to another embodiment of the present invention.
Figure 3 shows the movement of jaws and the whole assembly according to the first embodiment of the present invention.
Figure 4 shows the movement of jaws and the whole assembly according to another embodiment of the present invention.
Figure 5 shows the positions of the two jaws during the cycle showing engagement of jaws before & after the centre position.
Detailed description of the drawings:
For the purpose of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless, be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated package, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates.
It will be understood by those skilled in the art that the foregoing general description and the following detailed description are exemplary and explanatory of the invention and are not intended to be restrictive thereof.
In the method of the present invention the sealing machine is continuously moved, where jaws moved by eccentric drives. The folded film/laminate runs continuously despite contact of sealing jaws for a certain distance for sealing. The jaws are pressed for certain distance which provides sufficient hold time for perfect sealing without additional time of hold thus offering shorter cycle time. In order to further increase the hold time for sealing in the same distance but maintaining the same overall cycle time, electronically controlled programmable drive is used to provide faster speed of rotation in the non contact path of the jaws whereas slower speed during the pressing phase of the jaws.
The length of the pair of jaws depends on the width of the single stick pack, Sachet or pouch to be sealed or collective width of formed tube making multiple stick packs, sachets or pouches reaching simultaneously for sealing in case of multi track machine.
In the method of the present invention pouches or packs are formed individually or in continuous strip. The packs or pouches in continuous strip are separated by perforations or easy tear cuts or laser scoring for easy tearing.
Figure-1 shows the isometric view of the sealing and drive mechanism and radial movement of the jaws by eccentric drive levers. As shown in the figure, the sealing area l0' is the pressing surface of the front jaw (1) and the rear jaw (2). The two jaws move in their path through a set of gear drives (4) and (5). The gear drives shafts (9) provide the eccentric motion to the jaws brackets (8) through a set of levers (3) attached with the shaft of one side gear drive (5) and similarly another set of levers attached with the shaft of other side gear drive (4) as shown in the figure. The gear drives on both the sides are synchronized. The jaws, when in the middle, move from top to bottom in continuous motion and the two jaws come in contact with each other with Film or laminate in their path for a distance, in continuous motion (as shown in figure-5). The mechanism involved here facilitate the two jaws to come in contact just before reaching the extreme forward position at '0" and remain in contact just after '0'. To achieve this either the front or the rear jaw is kept longer or fixed forward by certain length with respect to the
other jaw. A flexible force, by suitable means like a Compression spring(s) (6) is provided on the back of either front or rear jaw or both the jaws, which provide sufficient cushioning effect during sealing and prevents the damage to the packaging material within the contact surfaces of the jaws. The cushioning effect is helped in providing pressing force necessary for the sealing of the packaging material.
Figure 2 shows the isometric view of the drive mechanism and the radial movement of jaws by eccentric pin on the drive shaft. As shown in the figure, the sealing area '0' is the pressing surface of the front jaw (1) and the rear jaw (2). The two jaws move in their path through a set of gear drives (4) and (5). The gear drives shafts (9) provide the eccentric motion to the jaws brackets (8) through an eccentric drive pin (7) on the face of each gear drive shaft. The drives on both the sides are synchronized. When the jaws are in the middle position, they move from top to bottom in continuous motion and the two jaws come in contact with each other with film or laminate in their path for a distance, in continuous motion (as shown in figure-5). The mechanism involved here facilitates the two jaws to come in contact even before reaching the extreme forward position at '0" and remain in contact after 'O'. To achieve this either the front or the rear jaw is kept longer or fixed forward by certain length with respect to the other jaw. A flexible force, by suitable means like a Compression spring(s) (6) is provided on the back of either front or rear jaw or both the jaws, which provide sufficient cushioning effect during sealing and prevents the damage to the package material within the contact surfaces of the jaws. The cushioning effect is designed to offer pressing force necessary for the sealing of the packaging material.
Figure 3 shows the movement of the jaws & the whole assembly by eccentric drive levers during the sealing cycle. It shows the four positions of the sealing jaws in their path. In position T the sealing jaws meet together in extreme forward position to seal the packaging material. As the shaft rotates 90 degree the jaws reach position 'IF which is the lowest position of the jaws. Further 90 degree rotation of the shafts brings the jaws in position 'III' which is extreme backward position of the jaws. In position 'IV' the two jaws reach top position and halfway forward position.
Figure 4 shows the movement of jaws & the whole assembly by eccentric pin on the drive shaft, during the sealing cycle. It shows the eccentric movement of the jaws in their path. The cycle and the positions of jaws & assembly remain same as in figure-3 except that the eccentric motion provided by lever (3) in figure 1 & figure 3 is replaced by eccentric pin (7) on the face of the gear drive shafts. In this case the extreme movements of the jaws & assembly are smaller than provided by the levers in figure 1 & figure 3. However this makes the total assembly very compact which is useful in applications like in stick pack machine when the package width & length are smaller but speed is fast.
Figure 5 shows the positions of the two jaws during the cycle and also shows the engagement of jaws before & after the centre position. In the conventional machines the sealing is done intermittently i.e. the jaws move forward, hold for sealing & retract back. The packaging film/laminate formed tube flow stops during this period & moves again when the jaws retract. This intermittent motion of formed tube of film/laminate limits the speed of the process. In the present invention, as shown in the figure-5, the formed tube of packaging film/laminate (10) is pressed between the jaws before reaching the centre position, at 'A', in continuous movement downwards & kept pressed for sealing till 'C. Then the jaws start
retracting & formed tube of packaging film/laminate (10) keeps moving downwards. This cycle offers continuous movement of film/laminate & jaws but offering desired sealing hold time due to the gripping of film/laminate by jaws from 'A' to 'C. In order to increase the hold time for sealing from 'A' to 'C but maintaining the same overall cycle time, electronically controlled programmable drive is used to provide faster speed of rotation in the non contact path of the jaws whereas slower speed during the pressing phase of the jaws. Continuous motion of the sealing jaws instead of intermittent motion allows much higher operating speeds & low wear & tear.
All documents cited in the description are incorporated herein by reference. The present invention is not to be limited in scope by the specific embodiments and examples, which are intended as illustrations of a number of aspects of the invention and embodiments which are functionally equivalent are within the scope of this invention. Those skilled in the art will know or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. These and all other equivalents are intended to be encompassed by the following claims.

We claim:
1. A high speed sealing method for making film or laminated packs or pouches on single or multi
track machines. The said method comprises the steps of:
• continuous motion of the sealing jaws in their path through a set of gear drives.
• providing an eccentric motion to the sealing jaws brackets by gear drive shafts, through a set of levers attached with the shaft of one side gear drive and another set of levers attached with the shaft of other side gear drive
• keeping the front or the rear jaw longer or fixing one of said jaws forward by certain distance with respect to the other jaw such that when both the jaws move from top to bottom, they start pressing the film or laminate between them before the middle position till after the middle position in continuous motion, which increases the sealing hold time without increasing the total cycle time
• providing cushioning effect during sealing which also prevent damage to the film or laminated within the contact surfaces of the jaws by providing adjustable or fixed flexible force by a means on the back of either front or rear jaw or both the jaws.

2. The method as claimed in claim 1, wherein the gear drives to move the jaws on both the sides are synchronized.
3. The method as claimed in claim 1, wherein the sealing hold time is increased without increasing the total cycle time by an electronically controlled drive or suitable mechanical or electro-mechanical means.
4. The method as claimed in claim 3, wherein said electronically controlled drive or suitable mechanical or electro-mechanical means provides faster speed of rotation in the non contact path and slower speed during the sealing and holding phase of the jaws.

5. The method as claimed in claim 1, wherein pouches or packs are formed individually or in continuous strip , wherein said packs or pouches are separated by perforations or easy tear cuts or laser scoring for easy tearing.
6. A high speed sealing method for making film or laminated packs or pouches on single or multi track machines, said method comprising the steps of:

• Continuous motion of the sealing jaws in their path through a set of gear drives
• Providing rotary motion to jaw brackets through a set of eccentric drive pins on the face of each gear drive shaft
• keeping the front or the rear jaw longer or fixing one of said jaws forward by certain distance with respect to the other jaw such that when both the jaws move from top to bottom, they start pressing the film or laminate between them before the middle position till after the middle position in continuous motion, which increases the sealing hold time without increasing the total cycle time
• Providing cushioning effect during sealing which also prevent damage to the film or laminated within the contact surfaces of the jaws by providing adjustable or fixed flexible force by a means on the back of either front or rear jaw or both the jaws.
7. The method as claimed in claim 6, wherein the gear drives to move the jaws on both the sides are synchronized.
8. The method as claimed in claim 6, wherein the sealing hold time is increased without increasing the total cycle time by an electronically controlled drive or suitable mechanical or electro-mechanical means.
9. The method as claimed in claim 8, wherein said electronically controlled drive or suitable
mechanical or electro-mechanical means provides faster speed of rotation in the non contact path and
slower speed during the sealing and holding phase of the jaws.
10. The method as claimed in claim 6, wherein pouches are formed individually or in continuous strip of packs or pouches, wherein said packs or pouches are separated by perforations or easy tear cuts or laser scoring for easy tearing.
11. A high speed sealing method for making film or laminated packs or pouches on single or multi track machines substantially as herein described with reference to the accompanying drawings.