Injection device for life-saving air bag

The invention relates to an injection device for a life-saving air bag, comprising a three-way shell, one end of the shell is an intake end for communicating with a high-pressure gas intake while the other end of which is an outtake end for communicating with the air bag and the final end of which is an air door end for communicating with outside atmosphere, the three ends are intercommunicated, an end cover is arranged on the air door end, an air door hole is formed on the end cover, an air door pressing plate capable of opening and closing the air door hole through elastic deformation underair pressure at two sides of the air door hole is fixed at an inner side of the end cover, and the air door pressing plate comprises a fixed part which is fixed on the end cover, and an elastic bending part which covers and seals the air door hole. The device not only can be reused, but also has no chemical safety problems; air is inhaled under negative pressure which is generated while injectinghigh-pressure gas in the air bag, and the air door can be automatically closed in an air inflation process. The whole device is light in weight, reliable in sealing, large in injection ratio, automatic in pull-in after injection and very convenient in use and maintenance.