US Patent 7153133 Disposable prophy angle for an electric tooth polisher

A disposable prophy angle for an electric tooth polisher, having a handle and a polishing head, has a body and a transmission assembly. The body is mounted to the handle and has a cavity and a bent distal segment. The transmission assembly is mounted in the cavity and has a rotatable driving shaft, a rotatable head mount and multiple linkage shafts. The driving shaft has multiple mounting holes. The head mount is connected to the polishing head and has multiple mounting holes. Each linkage shaft has two segments rotatably and slidably extending into a corresponding mounting hole in the driving shaft and a corresponding hole in the head mount, respectively. The linkage shafts are simple and small so the corresponding bent distal segment of the body holding the linkage shafts is also small. Therefore, the disposable prophy angle can be easily inserted into and moved around in a person's mouth.