| 摘要 |
1,194,137. Ladders. R. D. WERNER CO. Inc. 13 Sept., 1968 [19 Oct., 1967], No. 43582/ 68. Heading A6L. '[Also in Divisions F2 and B3] Ladders are constructed using ferrules to correct the rung ends to the rails by fitting malleable ferrule blanks loosely on the rung ends, crimping their ends and then deforming them to give two annular nodes 40, 41, one on each side of a preformed hole in the web 24 of the channel-isectioned rail. The rung may be D-sectioned, and the ferrule blank may be similarly shaped, and have a transverse crease formed in its flat side during the crimping operation to assist the formation of the nodes. |
