| 摘要 |
Discs for devices such as automatic swimming pool cleaners are disclosed. The discs include a central aperture circumscribed by a central portion shaped generally in the form of a truncated cone. Forming discs in this manner more appropriately matches them to the structures of footpads which they surround in use, permitting greater amounts of the undersides of the discs to remain in contact with the surfaces to be cleaned. |
