| 摘要 |
The bore selector includes a housing with an upper end having at least a first bore and a lower end with at least second and third bores. The housing includes a central bore extending between the upper and lower ends. A tube has its upper end connected to the first bore and its lower end adjacent the second and third bores. A yoke having an aperture therethrough for passing the tube, is reciprocably mounted within the bore of the housing. The yoke includes cam slots receiving guide lugs projecting from the sides of the tube. A hydraulic actuating means is also mounted in the lower end of the housing for reciprocating the yoke whereby as the yoke is reciprocated within the housing, the guide lugs move within the cam slots to shift the lower end of the tube between the second and third bores. A cage is mounted within the lower end of the housing to ensure alignment and sealing engagement between the lower end of the tube and the face of the housing around the second and third bores.
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