| 摘要 |
Extensible bellows are made from annular pieces of metal or plastics sheet or foil by prefabricating pairs of hoops joined at their outer rims, then assembling such single-bellows units by joining their inner rims. A two-part press tool with lips to support the bellows rims is used to consolidate the joints of bellows assemblies by fusion welding or adhesive bonding. For porous bellows, the joints may be discontinuous. The press tool may be fitted with alignment pads and/or a trimming knife. For making bellows of any required length, e.g. for covers for pistons or for lead screws etc. on tensile testing machines. The structure is less stiff and provides a higher ratio of extended to collapsed length than bellows made in one piece with radiused undulating inner and/or outer bellows crests. |
