The present application relates to packaging apparatus and more particularly to a sealing system for a packaging apparatus.
Packaging apparatus have been provided that are used to seal product within wrapped film. Typically, a film sheet is formed into a tube or folded and product is placed in the tube or folded film. A sealing system is used to seal and sever the tube or folded film to form a bag with product located therein that is separated from the film sheet.
U.S. Pat. No. 5,131,213 provides a sealing jaw apparatus for a plastic film wrapping machine. The sealing jaw apparatus provides a heated sealing jaw with a reciprocal knife. The jaw operates against a heated elastomeric bed that has a slot to receive the knife during a cutting operation.
In an aspect, a sealing jaw apparatus for a film wrapping machine utilizes a continuous web of thermoplastic film. The sealing jaw apparatus includes a first jaw unit to one side of a film travel path. The first jaw unit includes spaced-apart clamp arms and a heated sealing bar located between the spaced-apart clamp arms. The heated sealing bar includes spaced-apart noses defining a slot therebetween. A second jaw unit is to an opposite side of the film travel path. The second jaw unit includes spaced-apart gripping surfaces that are engaged by the spaced-apart clamp arms for gripping the thermoplastic film. Spaced-apart sealing surfaces are engaged by the noses of the heated sealing bar for sealing the thermoplastic film at spaced-apart locations in a film running direction. A knife assembly severs the thermoplastic film between the spaced-apart locations.
In another aspect, a method of sealing layers of plastic film from a continuous film web is provided. The method includes engaging the layers between a first jaw unit and a second jaw unit. The first jaw unit includes spaced-apart clamp arms that engage spaced-apart gripping surfaces of the second jaw unit. The layers are sealed at two seal locations that are spaced-apart in a web running direction using a heated sealing bar carried by the first jaw unit and located between the spaced-apart clamp arms. The sealing bar includes spaced-apart noses defining a slot therebetween. The spaced-apart noses engage spaced-apart sealing surfaces carried by the second jaw unit. The layers are severed between the first and second seal locations using a knife assembly carried by the second jaw unit.
In another aspect, a sealing jaw apparatus for a film wrapping machine utilizes a continuous web of thermoplastic film. The sealing jaw apparatus includes a first jaw unit to one side of a film travel path. The first jaw unit includes spaced-apart clamp arms and a heated sealing bar located between the spaced-apart clamp arms. The heated sealing bar includes spaced-apart noses defining a slot therebetween. A second jaw unit is to an opposite side of the film travel path. The second jaw unit includes spaced-apart gripping surfaces that are engaged by the spaced-apart clamp arms for gripping the thermoplastic film and spaced-apart sealing surfaces that are engaged by the noses of the heated sealing bar for sealing the thermoplastic film at spaced-apart locations in a film running direction. A knife assembly is provided for severing the thermoplastic film between the spaced-apart locations. The heated sealing bar moves relative to the knife assembly to bring the noses into contact with the spaced-apart sealing surfaces.
The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims.
a are diagrammatic, side section views of an embodiment of a sealing system for use in a packaging apparatus; and
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The first sealing jaw 12 includes outer, spaced-apart clamp arms 16 and 18. The clamp arms 16 and 18 have a respective gripping member 20 and 22 that is used to grip the film material. The gripping members 20 and 22 may be formed of a resilient material such as an elastomer or rubber and may be press fit or otherwise attached within grooves 24 and 26 in the clamp arms 16 and 18. The gripping members 20 and 22 may also include contoured gripping surfaces 28 and 30, for example, having two peaks separated by a valley as shown in
Located between the spaced-apart clamp arms 16 and 18 is a heated sealing bar 32. The sealing bar 32 is heated by a heating element 34 located between sealing bar members 36 and 38. Each sealing arm member 36 and 38 includes a respective nose 40 and 42 separated from each other thereby defining a slot 44 therebetween. As will be described below, the sealing bar 32 is extendable and retractable relative to the spaced-apart clamp arms 16 and 18. The sealing bar 32 may be moveable using a linear actuator, such as a pneumatic cylinder. In some embodiments, the sealing bar 32 is biased (e.g., using a spring) toward the retracted position shown in
The second sealing jaw 14 opposes the first sealing jaw 12. The second sealing jaw 14 includes support members 46 and 48 (e.g., formed of metal, such as aluminum or steel) that are arranged to engage with the gripping surfaces 28, 30 of the spaced-apart clamp arms 16 and 18. The support members 46 and 48 also provide support for sealing members 50 and 52, which are located within recesses 58 and 60 formed in the support members. The sealing members 50, 52 provide sealing surfaces 54 and 56 that engage the noses 40 and 42 of the heated sealing bar 32. In some embodiments, the sealing members 46 and 48 are formed of a resilient material, such as rubber.
A knife assembly 62 is carried by the second sealing jaw 14. The knife assembly 62 includes a blade 64 and a blade clamp 66. As shown in
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The above-described sealing system 10 can provide a low energy system operating at temperatures between about 180° F. and about 220° F. Advantageously, the knife assembly is located on the jaw opposite the heated sealing bar.
It is to be clearly understood that the above description is intended by way of illustration and example only and is not intended to be taken by way of limitation, and that changes and modifications are possible. Accordingly, other embodiments are within the scope of the following claims.