| 摘要 |
<p>A retractable canopy for a working area, sports enclosure, or exhibition etc. is supported by semi circular hoops (1-4) which are connected at each side to a common pivot point. The extremity of each hoop carries a toothed segment each of which meshes with a similar toothed segment (11, 12) by means of which it is rotated about its pivot point. The driving segments are all connected to a common shaft (10) so that only one drive is required to raise and lower all the hoops. This drive can be a motor driven screw which extends to swing an arm connected to the common shaft.</p> |
