| 主权项 |
1. A spade bit adaptor for centering a spade bit in an existing opening to be enlarged by the spade bit, the spade bit including a shaft and a head, the shaft having a proximal end and having a distal end connected to the head, the head having a tip and cutting blades extending laterally with respect to the tip, the spade bit having a longitudinal axis along which the shaft and tip extend, the spade bit adaptor comprising:
a mount adapted for releasable mounting on the spade bit, the mount being configured to engage the shaft of the spade bit when the mount is mounted on the spade bit, the mount including a proximal portion and a distal portion positioned distally from the proximal portion, the mount including a spade bit shaft receiving opening in the proximal portion sized and positioned for permitting the shaft to extend out of said opening away from the distal portion when the mount is mounted on the spade bit for exposing the proximal end of the shaft outside the mount; and a guide on the distal portion of the mount, the guide being adapted for guiding the tip of the spade bit into the existing opening in a position in which the tip of the spade bit is centered in the opening; wherein the mount is configured to align the longitudinal axis of the spade bit with the guide by engagement of the mount with the shaft and the tip of the spade bit when the mount is mounted on the spade bit; wherein the mount includes a collet having spade bit engaging surfaces adapted for engaging the shaft of the spade bit, the spade bit engaging surfaces being selectively positionable with respect to each other for engaging the spade bit engaging surfaces with the shaft to orient the shaft with respect to the guide. |
