| 摘要 |
A spring roller-mounted pull-out screen for use as a child safety barrier across a doorway has a control mechanism which prevents the screen from extending when impacted by a child. The roller is locked against rotation in a direction allowing the screen to unwind unless released by a manual push-button. The roller automatically locks after the screen has been extended and fitted in place. The automatic locking mechanism operates by a friction drive which releases a pawl to spring into engagement with a ratchet wheel when the screen has been pulled out and released. |
