U.S. Pat. No. 5,465,443 to Rice, et al., illustrates and describes various discs (and other components) of automatic swimming pool cleaners (APCs). The discs of the Rice patent typically are flexible, unitary structures defining central apertures for receiving footpads of APCs. Disc flexibility is advantageous for many reasons; flexible discs may bend when vertical or angled walls are encountered, for example, and adhere better to bottom surfaces of pools when surrounding areas are evacuated. Flexible discs additionally may more easily ride over objects extending upward from the bottom surfaces of pools as the APCs traverse those surfaces.
Many existing discs have upper surfaces that are mostly, if not entirely, planar. This is true for discs illustrated in the Rice patent, in which only peripheral fins extend upward from the upper surfaces. Regions of the upper surfaces adjacent the central apertures, by contrast, lack upwardly-extending protrusions. See, e.g., Rice, FIG. 6.
U.S. Patent Application Publication No. 2007/0261183 of Moore, et al., depicts additional discs and other components of APCs. Unlike discs of the Rice patent, those of the Moore application are not necessarily unitary structures, but instead may be formed of multiple parts. As illustrated, the discs may comprise forward, mid-, and rear sections. Although all sections are, to substantial extent, flexible, the mid- and rear sections beneficially are more flexible than are the forward sections. As noted in the Moore application, “Enhanced rigidity of [the] forward section additionally inhibits its assuming the shape of a corner or other transition within a pool . . . and prevents [the] forward section from folding under itself when departing from vertical surfaces such as walls.” See Moore, p. 3, col. 2, ¶ 0045 (numerals omitted). In turn, the greater flexibility of the mid- and rear sections provides improved sealing of the disc to surfaces and may improve the ability of APCs to climb pool walls. See id., ¶ 0046. However, notwithstanding enhanced rigidity of the forward section, it nevertheless may, at times, fold under itself in use.
Like the discs of the Rice patent, those of the Moore application have generally planar upper surfaces. This is especially true for the mid- and rear sections of the discs. It likewise is true for the forward sections of the discs, although upwardly-extending peripheral fins again are shown.
U.S. Pat. No. 6,049,933 to McLaughlin shows yet other APCs having bodies to which flexible discs may be attached via footpads. Also illustrated as attached to the bodies are bumper assemblies, which often function as leading edges of the cleaners. The exemplary bumper assemblies of the McLaughlin patent may include bumpers comprising main frame and fins. Whereas the fins are normally composed of flexible material, the main frames are substantially rigid. See McLaughlin, col. 2, ll. 50-67.
As depicted especially in FIG. 2 of the McLaughlin patent, no direct connection between the disc and bumper assembly exists. This is consistent with conventional designs of APCs, in which the generally planar surfaces of discs are configured intentionally to be unfettered. Indeed, past efforts of restricting (nominally vertical) movement of the generally planar surfaces have resembled the systems of U.S. Pat. No. 5,014,382 to Kallenbach, in which weight retainers separate from the discs have been used to “stop” upward movement of the discs.