Exchangeable ultrasonic welding module for welding longitudinal reinforcing folds in packaging film inside packaging machine and method of its use

An exchangeable ultrasonic welding module contains an ultrasonic transducer assembly (4) with a horn (5) and an anvil (7). The module contains a member (1) provided with a guideway (8) in a mating guideway (18) on the frame (10) of a filling tube (14). A locking element (11) secures the member (1) and the frame (10) in a fixed position relative to each other. The member (1) is provided with an element (2) for linear motion of a sliding carriage (3) and an adjustable stop (6) for restricting the carriage movement (3). The ultrasonic transducer assembly (4) is firmly affixed to the carriage (3), whereas the anvil (7) is affixed to the member (1). The frame (10) may contain an adjustable stop (9) for locking the member (1) in a defined position as the member is inserted into the mating guideway (18).

RELATED APPLICATION

This application claims priority to Czech Republic patent application CZ2017-251, filed May 4, 2017, the disclosure of which is incorporated herein by reference in its entirety.

FIELD

This invention relates to an exchangeable ultrasonic welding module for welding longitudinal reinforcing folds in packaging film inside packaging machine and to a method of its use. The invention belongs to a technical field involving machines, appliances or equipment for packaging products or commodities. The invention can be used with both vertical and horizontal form-fill-seal flat film packaging machines.

RELATED ART

Where products or commodities are packaged in tubular-shape sachets using packaging machines, a requirement often arises for reinforcing such sachets with longitudinal folds. Sachets with such folds effectively retain their shape. These sachets generally contain two, three or four longitudinal reinforcing folds.

In packaging machines, longitudinal reinforcing folds are shaped using forming elements and welded by means of electrically-heated welding modules or ultrasonic welding modules of various types.

An advantage of ultrasonic welding modules over electrically-heated devices is their small size. Consequently, their use in a form-fill-seal flat film packaging machine does not increase the machine's total installation height or the drop height of the product or commodity, which might otherwise pose a greater risk of damage to the product or commodity. Another advantage is that they are easy to arrange around the filling tube, which enables filling tubes with optimum cross-sections to be used, and thus eliminate problems with products or commodities clogging in the filling tube.

Disadvantages of ultrasonic welding devices include their higher price, the need for precise relative adjustment of welding tools, i.e. the horn and the anvil, and the need for precise positioning of said ultrasonic welding modules with respect to the filling tube and the forming elements. The solution according to this invention eliminates these disadvantages to a considerable extent.

SUMMARY

Embodiments of the invention include an exchangeable ultrasonic welding module for welding longitudinal reinforcing folds in packaging film inside a packaging machine. In particular, it relates to the design solution for said modules disposed around the filling tube and to the method of their use or, more specifically, the method of their exchange.

The exchangeable ultrasonic welding module contains a standard ultrasonic transducer assembly with a horn. The horn is oriented opposite an anvil and the path of the film to be welded passes between them. In this arrangement, the horn can be adjusted with repeatable precision with respect to the anvil, and therefore can operate trouble-free.

The module also contains a member provided with a guideway for guiding a sliding motion along one axis within the mating guideway provided on the filling tube frame. One particular embodiment of the mating guideway involves a shaped groove with one end open to allow the member's guideway of an analogous shape to slide in and out. The guideway of the member is inserted all the way into the mating guideway.

The member and/or the frame contain a locking element which secures the member and the frame in a fixed position relative to each other. The locking element may take the form of a screw or a clamping joint. The member is further provided with an element for linear motion of a sliding carriage and with an adjustable stop which restricts the movement of the carriage or, more specifically, defines its end position. The element for linear motion of the carriage may comprise, in particular, a pneumatic cylinder, a servo drive with a threaded rod, or a similar device. A less advantageous but functional solution involves a hand-operated device, e.g. a hand-operated threaded rod. The ultrasonic transducer assembly is firmly affixed to the carriage, whereas the anvil is affixed to the frame. Utilities are supplied to the module via a combined connector with a cable. The linear motion of the carriage with the ultrasonic transducer assembly with respect to the anvil is particularly desirable for repair tasks or for introducing new film. Thanks to the principle of ultrasonic welding, the module is not hot and there is no risk of undesirable damage to the film, thus it is not necessary to open the module after the end of welding.

Preferably, the frame contains an adjustable stop to secure the member in a defined position as the member is inserted in the mating guideway. This is important for achieving a correct position of the module with respect to the filling tube. If no adjustable stop is provided, the end of the mating guideway can determine the position of the inserted member. However, this is only possible when the contact surfaces of the guideway and its mating guideway (more specifically, the member and the frame) have been produced to great precision.

Such arrangement enables the exchangeable ultrasonic welding module to be adjusted with repeatable precision with respect to the filling tube and to the forming elements, and therefore enables its use with multiple filling tubes for producing various formats of sachets by the user. The specific arrangement of exchangeable ultrasonic welding modules around the filling tube and their number depends on the desired shape of the transverse cross-section of the sachet, on the transverse cross-section of the filling tube, and is outside the scope of this invention.

The above-described designs enable costly ultrasonic welding modules to be employed using a new and effective method according to the invention. This invention relates to a method of use of this exchangeable ultrasonic welding module or, more specifically, to a method of exchanging it between different filling tubes. The number of filling tubes is not limited. The procedure comprises the following steps:removing a complete first filling tube, which is fitted with forming elements and exchangeable ultrasonic welding modules, from a packaging machine,unlocking the locking elements and sliding out the exchangeable ultrasonic welding modules from the mating guideway on the frame of the first filling tube,sliding the exchangeable ultrasonic welding modules all the way into the mating guideway on a second filling tube,placing the second filling tube, which is fitted with forming elements and exchangeable ultrasonic welding modules, into the packaging machine.

The stop in the mating guideway on the filling tube frame may preferably take the form of an adjustable stop.

DETAILED DESCRIPTION

An exemplary embodiment of an exchangeable ultrasonic welding module13and its setting in a frame10of a filling tube14contains a member1. Firmly affixed to the member1is an element2for linear motion of a sliding carriage3. Firmly set on the carriage3is an ultrasonic transducer assembly4so that the horn5of the ultrasonic welding transducer assembly4is oriented opposite the anvil7. The anvil7is affixed to the member1. The movement of the carriage3with the ultrasonic welding transducer assembly4is restricted by the adjustable stop6of the carriage3. The member1includes a guideway8. The ultrasonic welding module's13guideway8is inserted into the guideway's8mating guideway18, which is part of the frame10of the filling tube14. The exact working position of the exchangeable ultrasonic welding module13with respect to the filling tube14and forming elements16is determined by an adjustable stop9of the member1and secured by a locking element11. The exchangeable ultrasonic welding module13is provided with a combined connector12.

An exemplary method of use of exchangeable ultrasonic welding modules13according to the invention comprises the following operations during exchange between filling tubes14:removing a complete filling tube14fitted with forming elements16and exchangeable ultrasonic welding modules13from a packaging machine,unlocking the locking elements11and sliding out the exchangeable ultrasonic welding modules13from the mating guideway18to the guideway8,sliding exchangeable ultrasonic welding modules13all the way to the adjustable stop9into the mating guideway18to the guideway8on the second filling tube14,placing the second filling tube14fitted with exchangeable ultrasonic welding modules13into the packaging machine.

An exemplary embodiment is clear fromFIG. 1toFIG. 3.

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