| 摘要 |
<p>Disclosed is a measurement touch probe for use on a coordinate measuring machine. The probe has a stylus supporting member (50), supported for movement relative to a housing (12) on three pairs of serially connected linear air bearings (LB1, LB2, LB3), each of which extend in mutually orthogonal directions. Air is serially supplied to each of the bearings; air is supplied from the housing directly to the bearing (LB1); a controlled venting of the air from bearing (LB1) supplies bearing (LB2); and a controlled venting of the air from bearing (LB2) supplies bearing (LB3). This obviates the need for pipe connections between relatively fixed and movable parts of a bearing which would otherwise restrict relative motion of the two parts. The construction of bearing (Figs. 3 and 4) comprises a cylindrical shaft (114) over which a cylindrical sleeve (116) is movable. Air is piped out of the centre of the shaft via an outlet port (160) and passes through collection chamber (162) into a plenum chamber (166) which is at supplied pressure. Restrictor outlets (176A-D and 178A-D) are supplied from the plenum chamber to provide the air cushion on which the sleeve (116) moves. Collection chamber (162) permits relative movement of the sleeve (116) and shaft (114) while ensuring that air passes from outlet (160) into plenum chamber (166).</p> |
