| 摘要 |
The spacer (1) has a superposed upper layer (2) comprising a titanium plate at a notched surface, a superposed lower layer (3) with same structure as the layer (2) and a superposed intermediate layer (4) that is made up of a material different from the layers (2, 3) and is rigid. The layer (4) is made up of an elastic material e.g. elastomer plastic material such as polyaddition or condensation polymerization silicon plastic material or polyurethane plastic material. The layer (4) has holes regularly or irregularly distributed in the layer (4). |
