U.S. Patent No. 4,677,798

A page from US Patent No 4677798.

A page from US Patent No 4677798.A page from US Patent No 4677798.A page from US Patent No 4677798.A page from US Patent No 4677798.A page from US Patent No 4677798.A page from US Patent No 4677798.A page from US Patent No 4677798.