The cylinder asm
consists of two parts- the lower part is a cylinder with
cushioning; the upper part is a set of screwing mechanism.
The lower
part：in the cylinder the
up&down movement of piston realizes close&open operations
of door, using the air pressure to drive the screw shaft to lift
and drop through the piston movement.
The upper part has
three components:
Support:it
funcions as①the connector between the
upper screw mechanism and lower cylinder;②guiding to the screw shaft
working with the spline;③the bracket of the outer
sleeve;④the primary bearing of the
total door weight(thus should be strong enough).
