| 摘要 |
Disclosed is an embodiment (60) of an improved vernier control device for selectively moving an object in gross or incremental, vernier amounts of the type comprising a housing (2) fixed against movement with respect to the object to be moved having an open-ended bore (4) extending therethrough having threads (6) disposed on wall (7) of the housing surrounding bore (6). Bore (6) contains a sleeve (8) that is moveable both axially and rotatably within the housing bore and has one end rotatably connected to the object and a bore (10) therewithin extending from the opposite end. An operating rod (30) is disposed within and is at least axially moveable within the sleeve bore. Device 60 is provided with lower friction and improved resistance to thread wear and the ability to withstand increased axial force on the threads as a result of the sleeve having a pair of apertures (35) through opposite walls through which respective thread engagement members (34) are able to be moved radially outwardly into threaded engagement with the threads in response to movement of an intermediate member (36) by movement of the rod axially to a thread engagement position within the sleeve bore so that rotation of the sleeve causes the object to move in vernier amounts and movement of the rod towards the end of the sleeve connected to the object enables members (34) to move radially inwardly through the respective apertures an amount sufficient to cause disengagement with the threads and enables the sleeve to be moved axially within the housing bore and move the object in gross amounts. |
