Help: Ernie Ball Steelguitar

I came across an old Ernie Ball steelguitar with keyless tuners.
I took off the old strings en replaces them with new ones. at leat I tried.
When I turn the wrench on the keyless tuner ti tighten the string I hear a rattling sound.
Looks as if inside the tuner is a mechanism to hold the string in tune.
But when I release the wrench the mechanism releases the new string. :confused:

Can anybody tell me what I a doing wrong.
Can it be that the keyless tuners are worn out of defect or is there something else I should do to keep the strings tightened?

Joost