| 摘要 |
<p>A down hole surveying tool (10) for directional surveying of boreholes. The tool (10) comprises a body (11) which accommodates a sensor device (17). The sensor device (17) is supported in a rotary mount (31) for rotation about an indexing axis (4). The sensor device (17) can be indexed about the indexing axis between two indexing positions which are 180 degrees apart. An indexing mechanism (70) is provided for selectively indexing the sensor device (17) about the indexing axis (4). The indexing mechanism (70) comprises a drive portion (71) and a driven portion (72) adapted for selective interaction to impart indexing motion to the sensor device (17). The driven portion (72) is movable into and out of engagement with the drive portion (71) upon rotation of the rotary mount (31) about a pitch axis (1) using a pitch drive mechanism (51). A translating electrical connection is provided for electrical connectivity between the rotary mount (31) and a base (23) which is part of the body (11) and which accommodates electronic circuitry for the surveying tool (10). The translating electrical connection comprises a flexible connecting cable (110) extending between the rotary mount (31) and the electronic circuitry, with one end section (111) of the cable (110) connected to the rotary mount (31), the other end section (112) connected to the electronic circuitry, and the intermediate section (113) configured as a loop (115). The loop (115) is accommodated in a cable receptacle (117) and is adapted to undergo translation to accommodate relative movement between the rotary mount (31) and the electronic circuitry.</p> |
