TANDEM VACUUM BOOSTER WITH EXTENSIBLE BELLOW AIR SLEEVE

A tandem vacuum booster includes an internal air passage connection between primary and secondary high pressure chambers of the booster, and extending through a primary low pressure chamber of the booster. The internal air passage connection includes a tubular collar extending longitudinally from a divider separating the secondary high pressure and primary low pressure chambers, and an extensible air tube extending through and from a primary diaphragm of the booster, with the primary diaphragm defining the boundary between the primary high and low pressure chambers. The collar includes an outer surface thereof adapted for receiving a distal end of the extensible air tube extending over a portion of the outer surface of the collar. The distal ends of the collar and the air tube include elements for retaining and/or sealing the distal end of the extensible tube against the outer surface of the collar. The booster also includes a primary diaphragm support disposed for contacting a front surface of the primary diaphragm, and having a hole therein for passage therethrough of the extensible air tube, with the air tube including a locking bead on an outer surface thereof for engaging the primary diaphragm support around the hole, to thereby restrain movement of the extensible air tube relative to the diaphragm support and preclude chafing of the air tube that could occur if the air tube were not retained in the hole of the primary diaphragm support.