Cordless surgical handpiece with disposable battery; and method

A surgical instrument for performing a surgical procedure on bone or hard tissue, comprising:

• (a) a handpiece having a tool supporting end, and a battery receiving end with an alignment post extending therefrom, the battery receiving end of the handpiece also having a set of electrical contact elements arranged in generally concentric relation to the alignment post;
• (b) a battery pack having an attachment end with a central opening therein, and a set of mating electrical contact elements arranged in a generally circular configuration concentric to the central opening;
• (c) the central opening in the battery pack being adapted to receive the alignment post of the handpiece in a partially inserted position so as to establish a pre-attachment alignment thereof;
• (d) the sets of mating contacts being adapted to come into a mutually concentric relation in response to a further insertion of the alignment post into the central opening;
• (e) the sets of contacts upon rotation of the battery pack relative to the handpiece being adapted to then become lockingly and conductively interengaged in a predetermined relative position of the battery pack and handpiece, so as to achieve correct alignment of the parts and ensure stable mechanical attachment and support during the surgical procedure;
• and
• (f) means for indicating by at least one of sight, sound, and touch that the predetermined relative position has been achieved.