The inner part of the clamping claw and the end face of the clamping claw are used for holding an annular part in an inner support.

NPPV was delivered to the patient by a face mask connected to a ventilator set in pressure support ventilation (PSV) and positive end-expiratory pressure (PEEP).

Analysing the roof-fall cause of end face and support system, an effective way to reduce roof fall sensitivity and improving production efficiency are pointed out.