Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
1998-12-14
2001-02-06
Ball, Michael W. (Department: 1733)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S088000, C156S091000, C156S093000, C428S076000
Reexamination Certificate
active
06183579
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The field of the present invention relates generally to the assembly of evaporative cooler pads that are used in evaporative coolers for absorbing water to cool warm air that flows through the cooler pad and into a cooling system. In particular, the present invention relates to the manufacturing of evaporative cooler pads that utilize absorbent media contained in a mesh material.
2. Background
Evaporative cooler systems are commonly used in warm areas having relatively low humidity to produce cool air for use to cool the interior of houses, businesses and other structures at a relatively low cost. Such systems employ an evaporative cooler having a cabinet-like housing with one or more cooler pads located on the outer edge(s) of the housing. The evaporative cooler housing is typically located on or near the structure to pull warm air into the cooler, cool the air and deliver it through one or more vents located in the structure to distribute cool air in the structure's interior. Cooling of the warm air is achieved by pulling warm air across the wetted cooler pad or pads with the use of a fan or blower mounted inside the housing. A water circulation system including a pump, source of water and a water distribution mechanism located inside the housing supplies water to the cooler pad to keep it in a wetted condition so that it can effectively cool the warm incoming air by evaporation.
The typical evaporative cooler housing is made into a square or rectangular shaped open frame, although other shapes are also suitable, that is configured to demountably hold a cooler pad containment structure at the open faces of the housing frame. Typically, the cooler pad containment structure contains the cooler pad in an upright position so that water from the water circulation system flows down across and through the cooler pad to wet substantially the entire absorbent media in the cooler pad. In general, the cooler pad is sized and configured to fit inside the containment structure so as to completely fill the open faces of the housing frame.
The wettable cooler pad medium may be formed of any suitable material that is capable of absorbing water and allowing air to pass through the cooler pad. Although recent cooler pads have utilized a number of synthetic materials as the wettable medium, the most commonly used material is wood excelsior. Excelsior cooler pads are generally made from fine aspen wood fibers which are interwoven in a randomly orientated pattern to form a highly porous, absorbent material that has been found to be very effective for evaporative cooler systems. The typical excelsior cooler pad has a plastic or cloth netting that contains the excelsior media in a square or rectangular pad shape. Spikes or wires used in the typical containment structure penetrate the cooler pad to hold the cooler pad in place against the open face of the housing and maintain it as a non-sagging mass.
The manufacturing of the excelsior cooler pad typically involves forming a continuous mat of excelsior fibers of the desired width and thickness on an automated conveyor belt assembly either directly from the excelsior manufacturing process or from bales of excelsior material. The netting, typically made of polypropylene material, is applied to the upper and lower surfaces of the cut mat to form a continuous flow between the upper and lower netting. A stitching machine sews stitching material into the pad to hold the excelsior pad between and to the upper and lower netting. The continuous sheet of pad and netting is cut to the desired length. To avoid loss of material from the cut ends of the pad, the ends are stitched or glued together or, alternatively, a narrow strip or piece of netting is applied to each end and then sewn or glued on. The end stitching or gluing requires a separate step in the manufacture of cooler pads presently available.
To avoid the extra step of sealing the ends, some cooler pad manufactures cut the excelsior pad prior to placing the netting on the pad so as to obtain a gap between pad sections that will only have netting. Glue is applied to the surface of the pad, including the netting gap, and then the netting between the pad sections is cut, leaving the ends sealed by the glued netting. Although this method of manufacturing avoids the necessity for an extra sealing step, it does not provide an end seal that is as strong and durable as desired or adequately secure the netting to the pad. What is needed is a process of manufacturing a cooler pad that provides a stitched cooler pad with ends that are sewn, without the need for the extra step of sewing the ends after manufacture of the cooler pad, and that has the netting securely combined with the excelsior fibers.
SUMMARY OF THE INVENTION
The method of manufacturing cooler pads of the present invention solves the problems identified above. That is to say, the present invention provides a process of manufacturing cooler pads that fixedly seals the ends of the cooler pads with sewing material without the need for a separate end sewing step and that securely connects the netting to the fibers. As such, the method of the present invention is particularly suitable for automated processes that provide continuous flow manufacturing of evaporative cooler pads.
In the primary embodiment of the present invention, the method of manufacturing evaporative cooler pads starts with a source of absorbable, porous media that is placed on a first conveyor belt assembly. The media is shaped into a continuous mat of such material and compressed into the desired width, thickness and density. A first cutting assembly cuts the continuous mat into individual mats having the desired length. The pulling action of a second conveyor belt assembly creates a gap between cut mats. After the second conveyor belt assembly pulls the cut mat away from the continuous mat, mesh netting is placed on the opposing upper and lower surfaces of the individual mats.
After covering the upper and lower surfaces of the mat and the gap between mats with netting, the method of the present invention folds the lower netting around the sides of the mat and over on top of the mat and applies rows of stitching to the netting and mat. The stitching fixedly attaches the netting to the upper and lower surfaces of the mat to contain the mat inside the netting material. The netting in the gap between mats is also stitched to seal the ends of the netting and avoid loss of mat material and sagging of the mat. After stitching, adhesive material is applied to the netting and stitching in the gap between mats by spraying or other mechanism to further seal the ends of the netting and keep the stitching from unraveling after it is cut. Compression rollers further compress the mat and a second cutting assembly cuts the netting between the mats to form a cooler pad of the desired length. A take-off conveyor belt assembly takes the completed cooler pad off the belt conveyor system.
Accordingly, the primary objective of the present invention is to provide a method of manufacturing evaporative cooler pads that provides a cooler pad that effectively contains the absorbent material in the cooler pad that does not require an extra finishing step to seal the ends of the pad.
It is also an important objective of the present invention to provide a method of manufacturing cooler pads that utilizes a system of continuous stitching to seal the ends of the cooler pad that is suitable for use with automated cooler pad manufacturing systems.
It is also an important objective of the present invention to provide a method of manufacturing cooler pads that seals the stitched ends of the cooler pad with an adhesive to further strengthen the ends thereof and keep the stitches from becoming unraveled or undone.
It is also an objective of the present invention to provide a method of manufacturing cooler pads with stitched and sealed ends that is suitable for use with different types of absorbent media to produce a variety of different size cooler pads.
The
Matthews Robert E.
Ware Udale G.
Ball Michael W.
PPS Packaging Company
Rossi Jessica
Ryan Richard A.
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