swivel-frame

from The Century Dictionary.

• noun A frame for the axles of the truck-wheels of a locomotive which is fastened to the main frame only by a pin or swinging frame, thus allowing it to turn or swivel; the frame for a car-truck which is fastened to the car by a single bolt and hence can swivel.
• noun In swivel-weaving, a movable frame for carrying a shuttle, attached to the front of the lay and raised and lowered by a cam, lever, or spring operated by a Jacquard.