| 摘要 |
An improved mattress inner spring unit having a plurality of coil springs arranged in rows with each coil spring being comprised of a series of convolutions. Each coil spring terminates in end convolutions which have offset portions formed thereon. The coil springs are arranged in the inner spring unit so that the offset portions extend into overlapping relation with adjacent offset portions. Such an arrangement allows the coil springs to be secured together by spirally rotating a helical coil across each of the rows so as to interlace the offset portions. The helical coils are thus positioned in both the upper and lower surfaces of the inner spring unit. When all adjacent offset portions have been interlaced with the helical coils, the end portions of each helical coil are compressed around the overlapped offset portions of the outermost row of coil springs. |
