Apparatus For Making Multiple Plastic Bags With Reclosable Fastener Thereon

What is this patent about?

'671 is related to the field of manufacturing plastic bags with reclosable fasteners. The background acknowledges the existing methods of creating such bags, which involve extruding the plastic film and fastener strips separately and then joining them. A key challenge is achieving a reliable, high-speed, continuous process for attaching the fastener strips to the film without compromising the integrity of the seal or the bag itself. Prior methods involved intermittent sealing, which limited production speed and control over heat application.

The underlying idea behind '671 is to create a continuous, high-speed method for attaching fastener strips to plastic film using continuous heat sealing, such as ultrasonic sealing. This involves guiding the film and fastener strips together, positioning an anvil to support the materials, and applying continuous heat and pressure to create a strong, consistent seal. The process aims to eliminate the need for intermittent sealing, thereby increasing production speed and improving seal reliability.

The claims of '671 focus on a mechanism for continuously forming material for making multiple bags, comprising a means for continuously supplying a plastic film, a means for guiding one or more sets of fastener strips to the surface of the film, an anvil positioned below the film, and a high-speed continuous heat sealing means for sealing the fastener strips to the film. The claims emphasize the simultaneous application of heat and pressure to create a continuous seal, as well as the ability to cut and separate the bags after the sealing process.

In practice, the invention can utilize different film configurations, including flattened plastic film tubes, folded film sheets, or flat film sheets. Fastener strips are guided and positioned onto the film, and an anvil provides support during the sealing process. The ultrasonic sealing horns apply continuous heat and pressure to fuse the fastener strips to the film. After sealing, the material is either rolled for later cutting or immediately cut into individual bags.

The key differentiation from prior approaches lies in the continuous nature of the sealing process. Unlike intermittent sealing methods, this invention allows for a constant and controlled application of heat and pressure, resulting in a more reliable and faster production rate. Furthermore, by extruding the fastener and the film separately, the most desirable resins can be used for each, optimizing both clarity and strength for the film, and slip and contour forming for the fastener. This avoids the compromises inherent in integral fastener film constructions.