Voice transmitter for a breathing protective mask

A voice transmitter for a breathing protective mask, the voice transmitter comprising:

• a housing having a base wall and an annular wall extending upwardly from said base wall;
• said annular wall defining a longitudinal axis and said base wall having an annular projection formed thereon and projecting upwardly from said base wall so as to be concentric with said annular wall;
• a clamping ring having a lower end facing toward said base wall and having an annular support surface formed as a ring-shaped rise on said lower end so as to be interdigitated with respect to said annular projection when said clamping ring is in said housing;
• said annular projection and said ring-shaped rise having respective flanks which are mutually adjacent;
• said annular wall of said housing and said clamping ring conjointly defining a threaded interface permitting said clamping ring to be moved along said longitudinal axis toward and away from said base wall when said clamping ring is rotated in said threaded interface about said longitudinal axis;
• a voice transmitting membrane subdivided into an annular outer portion fixedly clamped in said threaded interface and an inner portion spanned over said rise transversely to said longitudinal axis and in pressing contact engagement with said annular projection so as to permit adjusting said membrane in tension as said clamping ring is moved along said longitudinal axis;
• and,
• said ring-shaped rise having a first diameter (D1) and said annular projection having a second diameter (D2) less than said first diameter (D1) by an amount sufficient to ensure that said voice transmitting membrane is not sheared off between said mutually adjacent flanks when said tension of said membrane is adjusted.