| 摘要 |
The device for maintaining a ladder at a distance from a support comprises a pair of rectangular Y-assembled tubes (1,8,9) which are fixed in parallel by two square tubes (4,5). Mortises (7) fitted on the ladder rungs form tenons and are locked by pins. The spacer is length adjustable by means of two holes drilled in the rectangular tubes. It is width adjustable by means of three holes (6) drilled in the central square tube and locked by pins.
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