(57) Stem B consists of sections such as 14 and 19 which may be telescopic or screw together.
Top piece A screws onto the top of the stem B before the umbrella is opened. Collar
3 is then lowered by sliding on the stem top-piece 1 so that support ribs 5, pivotally-attached
to the collar 3, and main ribs 4, pivotally-attached to the flange 2 on the top-piece
1, swing outwards. Each main rib 4 is connected to a support rib 5 by a hinge 6, to
which is also connected an extension rib 7. The extension ribs 7 are swung over to
align with the main ribs 4 before the collar 3 is lowered to engage the latch on the
stem B, causing the covering fabric 8 to be stretched and the main and extension ribs
to adopt a bowed formation.
|

|