Liquid purification or separation – Filter – Handled
Reexamination Certificate
1997-11-04
2001-10-16
Savage, Matthew O. (Department: 1723)
Liquid purification or separation
Filter
Handled
C210S495000, C210S499000, C015S001700
Reexamination Certificate
active
06302277
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to swimming pool cleaning devices generally, and more specifically to an improved tool to remove debris from a swimming pool utilizing a frame with a net retained thereon by a retaining member.
Prior art devices, sometimes called “pool rakes”, “leaf rakes”, or “pool nets”, are used to skim, scoop, or otherwise remove, debris from swimming pools. Some parts of the rake tend to wear out. Especially vulnerable to wear is the “bag” or net component of the rake into which leaves and other debris are trapped as the rake is used to clean a swimming pool. After repeated or continued use, the bag may wear through at certain spots, may develop holes, the bag's stitching may break, or it otherwise fails. As a consequence, the bag typically is unable to remove, or is at least less effective in removing, debris from a pool. The bag needs to be replaced.
Some prior art assemblies are monolithic, in that they are designed for the entire assembly (the frame, net, etc.) to be discarded when the bag is damaged. This precludes separate replacement of the bag or other components.
Some prior art bags include multiple layers of bag material (at least on certain portions of the bag) which may help delay the bag's failure. For example. if a “wear spot” is a seam on the bag, an additional fabric layer at that location may postpone the “wear-through” at that location. Such bags also sometimes include combinations of various fabrics (some having finer meshes than others) which, like the multiple layer bags, can also help to trap “fine” particles from the water during cleaning. Even such “reinforced” bags, however, eventually tend to wear out.
To facilitate the needed bag replacement, as well as replacement of other parts which may become damaged or worn, some prior art devices are modular, and typically include a replaceable net sized and configured to fit a frame, a replaceable elongated clip to hold the net to the frame, and attachment means to attach the frame to a handle or pole. Any of these modular components (including the net, as mentioned above, as well as the elongated clip and/or the frame) can wear out or break while there is still useful life in one or more of the other components. Depending on the application, the user, and the design and manufacture of the device (among other factors), one or the other of the components can be more likely to wear out before the others.
Prior art attempts to permit modular assembly and/or replacement of parts have been less than satisfactory. Among other things, the prior art devices of which this inventor is aware do not permit ready assembly or removal of the elongated clip from the frame.
These prior art devices are typically designed so that many, if not most, components of the rake are not readily disassembled by the user (even though the devices may be intended to be disassemblable by the user, they may be difficult to do so). An elongated channel-shaped retaining means is commonly used to hold the edges of the fabric at the mouth portion of the bag around the frame means. The retaining means pinches the bag fabric and the frame means together and thereby holds the bag in place about the mouth of the frame.
This approach is not entirely practical nor consistently effective. Among other things, this type of assembly is most effective with the seams of the bag oriented so that the shape of the bag's “mouth” matches the frame. The seams are thus balanced in position on either side of the frame, which helps prevent unusual wear and awkwardness in using the tool. Many prior art nets of this type do not provide any easy way to orient the seam properly.
Furthermore, a typical retaining means in these modular assemblies tends to pinch more tightly around curved or bent portions of the frame and less tightly along straight portions of the frame and/or near the ends of the retaining means. As a result, sufficient debris or other objects caught in the bag can easily tug the bag so that the ends of the bag fabric will slip from between the frame means and the retaining means (such as a channel) at various points. The bag thus becomes at least partially disengaged from the frame.
This is an irritating inconvenience for the user since the efficiency of the rake is at least somewhat reduced by the bag slippage, and since further use typically requires disassembly and reassembly of the tool. Some devices, such as Purity leaf rakes, attempt to address this problem by providing a protruding portion located on an interior surface of the channel-shaped retaining means and a correspondingly sized and positioned groove or cavity in the frame means. These elements cooperatively interfit with the bag edge between them and thereby provide an extra measure of gripping to attempt to reduce or prevent the bag from slipping between the frame means and the retaining means. This is not always an effective solution, and in any case can increase the effort required to remove the retaining means during replacement of the net.
Some devices, such as the Aquality Gold Line Leaf Rake, additionally utilize rivets set through the retaining means, bag, and frame means in order to prevent the bag edge from slipping out of engagement with the frame. Consequently, the bag cannot be replaced without replacing the entire assembly.
As indicated above, other aspects of the bag replacement process are affected by the approach used. In certain circumstances and for certain prior art devices and assemblies, removal of the retaining means may be so difficult that a screwdriver or other implement is required to accomplish the removal of the retaining means from the frame means so that the bag may be replaced, by prying the clip from the frame. Sometimes this removal is so awkward or difficult that the net, the frame, and/or the clip itself can be further damaged or destroyed during the operation, or the user's hands can be injured.
In addition, although some prior art clips are assertedly shaped to assist in scooping up debris, their actual shape does not provide a smooth, uninterrupted ramping surface to urge the debris into the net.
As indicated above, in certain other prior art devices, including devices made by AquaPro and T&K, replacing the fabric bag requires that most or all of the components of the pool rake be completely disassembled so that the frame means of the tool can be slipped through a loop formed on the edge of the bag. This loop is usually formed by folding back the edge of the fabric which is at the mouth portion of the bag upon itself, then permanently sewing that edge to the side of the bag to create a pocket or loop through which the frame means may be fed. One or more openings in the loop, such as at the ends of the loop, allow the end or ends of the frame means to enter the loop. Typically, after the bag is completely slipped around the frame, both ends of the frame can be reassembled with the remaining components of the rake (in a manner that permits future disassembly and reassembly of those frame ends, for future bag replacement, etc.). Thus, the loop is the means by which the bag hangs on the frame. Although elongated channel-shaped retaining means are sometimes used with such prior art devices, such channels still suffer from the problems and shortcomings discussed herein. Among other things, changing a bag on a tool of this sort (especially one having a prior art elongated channel-shaped retaining means) is inconvenient because it is both time consuming and often difficult to accomplish.
Additionally, many prior art tools of this type are not adequately designed to withstand the forces that can be generated from normal use, and therefore break at the neck of the attachment to the handle or pole. This can result in catastrophic failure of the tool requiring replacement of the frame member, damage to the net, and related problems and costs.
Moreover, no prior art of which this inventor is aware has combined the potential economies of scale, manufacturing cost savings, durability, and other benefits of a
Holland J. Mark
Resh Eric
Savage Matthew O.
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