Thanks to G. Davis (040724 MMDigest)  for providing the information
regarding Tinnerman and Apex Fasteners in Monrovia, California.
From my investigations of the sites, it would appear that the Dynavoice
clamps are not Tinnerman push-on clamps after all.  Though of different
design, they have an item somewhat similar in application called "stud
receivers, self locking".

According to the picture on the opening page, the Apex web site
http://www.apexfasteners.com/  has push on clamps much closer in
appearance, nearly identical in design, to the original Dynavoice
clamps.  I was not able to go further to find out the exact description
or part number of what appeared to be a perfect substitute.  Hopefully
they are available in 7/16".

At this time, then, it is still a mystery as to the manufacturer of
the original clamps.

Tom Lear
San Francisco, Calif.