| 摘要 |
<p>Draw organs, wound up on drums, are seated on a setting and drawing spindle, and borne by ladder guides led across turning rollers on the spindle, in the concertina-folding slatted venetian blind. A coupling provides firm connection between spindle and roller, within a set slat swivelling range, and opens on reaching an end release unit. The coupling is a pawl ratchet. This comprises two opposite-way, radially sliding toothed pawls offset through 180 deg. in the roller together with a cogwheel on the spindle. The release unit, guides the locking pawl concerned out of engagement with the cogwheel. This provides reliable form-locking coupling, while still being accommodated inside the roller.</p> |
