| 摘要 |
When the sectors of the expander tool are draw-in together, in a radially-retracted position (R1), its working surfaces (2) form a true common cylinder. An Independent claim is included for the method of making the tool described. A body of rotation (e.g. formed by turning) is divided diametrally by axial cuts, forming a set of sectored expansion jaws (1). When clustered together, they are clamped, and are re-finished to the true cylindrical form, noting that each e.g. kerf thickness initially causes a departure (A) from circularity, when seen in cross section. Preferred features: The common cylindrical surface is beveled or rounded at its axially-leading edges which enter the pipe. In making the tool, the working faces are finished cylindrically, by a rotary grinding process. The body of rotation, e.g. a turning, is made with an integral hub (9) from which the expansion jaws project axially. The sectors are clamped together by a ring around this hub, to hold them in the retracted or clustered position (R1), during grinding.
|
