The torsional spring ends limit the rotation of the knob.
Door handle only opens one way.
Spray the mechanism with spray lubricant while you operate the barrel with the other handle.
I solved the problem by placing a command wire hook size large was a perfect fit under each handle.
So one cat opens the doors and the other chews up all the cables.
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I m sure this would work for your situation.
If the knob only turns in one direction then one of the rotational stops has likely slipped past the end of the torsional spring.
The door can only be opened by lifting up on the handle now.
Single sided or one sided active passage door knobs with a circular blank plate on one side of the door are now available with any of our emtek door knobs or door levers.