door knob turns vs door knob

Some examples from the web:

• Using a chair under the door knob is actually more effective.
• Pretend the door knob is an egg.
• He's got trouble with door knobs.
• I cut my finger on your damn door knob.
• He's got trouble with door knobs.
• - I saw the knob turn.
• Look, man, we are not sending you out to polish door knobs.
• All right, I'm gonna resist the impulse to ask you about the door knob.
• Hands are for door knobs and legs break down doors.
• An electrified door knob, shit!
• - You're slicker than snot on a door knob.
• You stay over my place for the weekend, And there's hair all over every pillow, and a bra on every door knob.
• But whenever I close the door, I purposefully lower the door knob to five millimeters below its highest position.
• Dead as a door knob, sir, with his face contorted, like he'd seen a ghost.
• Warped window frames, wet cellar, crayon marks all over the walls, filthy smudges around the door knob and the fixtures.
• Did he get it from a door knob?
• And he said, "Yes, except for the door knob because that gives everyone a handshake."
• Have we got anything to wedge against the door knob?
• And I read in this book that if you tie peace of string around your tooth and then tie the other end to a door knob you can slam the door and you baby tooth will come out.
• We did talk to a couple of folks at the bus stop, and one of them claims she saw someone turn a knob and open the door.

Some examples from the web:

• Using a chair under the door knob is actually more effective.
• Pretend the door knob is an egg.
• All right, I'm gonna resist the impulse to ask you about the door knob.
• An electrified door knob, shit!
• You stay over my place for the weekend, And there's hair all over every pillow, and a bra on every door knob.
• But whenever I close the door, I purposefully lower the door knob to five millimeters below its highest position.
• I cut my finger on your damn door knob.
• - You're slicker than snot on a door knob.
• Dead as a door knob, sir, with his face contorted, like he'd seen a ghost.
• Warped window frames, wet cellar, crayon marks all over the walls, filthy smudges around the door knob and the fixtures.
• Did he get it from a door knob?
• And he said, "Yes, except for the door knob because that gives everyone a handshake."
• Have we got anything to wedge against the door knob?
• And I read in this book that if you tie peace of string around your tooth and then tie the other end to a door knob you can slam the door and you baby tooth will come out.