| 摘要 |
PURPOSE: To reduce material fracture by forming around a water bag a reinforced seamless structural edge portion that has two sheets at which the top and bottom of the water bag, and the bonded edge portion is in touch with a top face portion of a mattress base. CONSTITUTION: A water bag of a water mattress has flat top portion 1a and bottom portion 1b bending downward formed thereon. The water bag is brought into contact with a recess 3 within mattress base 2, with the periphery of top portion 2a positioned around the wall of recess 3. Application of load P results in subjecting top portion 1a of the water bag to undergo generation of not only wrinkles starting from its edge portion to the exterior but also oblique folds. In the case of waving, the water bag encounters repeated movements, whereby it will experience material fracture and subsequent water leakage. To reduce the occurrence of folds, the water bag 1 is provided with reinforced frame-like edge portion 4, which is formed by welding top sheet 1a to bottom sheet 1b. Top sheet 1a is made flat while bottom sheet 1b is bent downward, with a configuration corresponding to the recess 3 of mattress base 2 thus formed. |
