of the frame has a curled flange around the edge (fig.
4), it is an early model assembly that must be discarded.
(1) Obtain a new crimping ring. Use a pair of
If the back surface of the frame is smooth (fig. 4), it is a
glass pliers to grasp and prebend the two large tabs
late model assembly. Check all late model assemblies
toward the center of the ring (fig. 6). Grasp the tab
removed from masks for damage to the frame or
approximately 1/8 inch from the edge. Bend the tabs
diaphragm; if undamaged, they may be reused.
inward so they are slightly (about 5 degrees) out of
Note. Only late model voicemitter-
alinement with the small tabs.
outlet valve assemblies will be used in the repair
(2) Insert the nosecup assembly into the
cavity of the facepiece. Aline the opening in the
(b) When repairing M17A1 masks,
nosecup with the matching opening in the facepiece.
check the voicemitter-outlet valve assembly (fig. 5) for
Pull the flange around the nosecup opening through the
damage to the frame, diaphragm, or drinking and
facepiece opening. Position the nosecup so that the
mold lines at both top and bottom of the nosecup flange
are alined with the mold lines at the top and bottom of
the facepiece opening. Arrange the nosecup flange so
(3) If the mask has an expander ring installed
that it lies flat over the facepiece flange beneath it.
in the nosecup opening, remove and retain the ring for
use during assembly.
(3) Seat a prebent crimping ring ((1) above)
around the voicemitter-outlet valve opening in the
(4) Remove and inspect the nosecup
facepiece (fig. 7). Fit the two rubber flanges over the
assembly. Discard the nosecup if the rubber is torn,
metal flange on the bottom of the crimping ring.
split,, or deformed, or if the inlet valves on the sides of
the nosecup are separated from the nosecup rubber. If
the nosecup is undamaged, set it aside for reuse.
Figure 4. ABC-M17 voicemitter-outlet valve assemblies