History Early Ford V-8 Anti-Chatter Rings?

Have any of you early Ford V-8 accessory guys ever seen or heard of
"Robison Anti-Chatter Rings"?
Made by Robison Air Jack Co, San Francisco CA, in the 1930's-40's.
They were stampings, made to clamp around the outer edge of the brake drums,
supposedly would reduce drum chatter.
These were applicable to mechanical brakes only up to 1936.
They were completely unlike the coiled spring-type appliances.
Any info greatly appreciated. Thank You.

 

Any chance this is what you are talking about?

Charlie Stephens

 

The coil spring thingies were more for cooling, weren't they?

 

Thanks Charlie Stevens and R Pope...
No, they are not the reinforcement type steel press-on rings
that are for Model A drums.
What I'm referring to are for '32-'36 cast iron drums,
and have an appearance similar to the lightweight steel securing bands
that hold the lids on to modern 55 gal plastic drums.
They are a "C" cross section stamping.