Coolant supply extension member in rotating cutting tool

Claim 1

A rotatable cylindrical extension member for attachment to a drive spindle of a cutting tool of the type for cutting a workpiece wherein there is relative cutting motion about an axis of rotation between a cutting member mounted upon a tool shank of the type for attachment to said extension member and having an axially extending bore therethrough, and said workpiece, and wherein coolant is supplied from a coolant supply means through a ring bore of a coolant supply ring rotatably mounted upon said extension member and through said bore in said tool shank to said cutting member, said cylindrical extension member comprising a longitudinal axis, a first end for coupling to said drive spindle, a second end for coupling to said tool shank, a coolant inlet means, for alignment with said ring bore, extending inwardly from the peripheral surface of said extension member, for directing said coolant towards said longitudinal axis when said extension member is coupled to said drive spindle and rotated while coolant is being supplied to said inlet means from said ring bore, said inlet means comprising two or more inlet bores each defined by an inlet bore wall extending from said peripheral surface to said longitudinal bore, said inlet bores being equally spaced circumferentially of said peripheral surface and being positioned relative to a centerline, defining an extension member diameter, such that each of said inlet bores is positioned behind said centerline with respect to the direction of intended rotation of said extension member; a coolant outlet at said second end for supplying coolant through said bore of said tool shank to said cutting member; a longitudinal bore defined by a longitudinal bore wall extending from said inlet means to said outlet and about said longitudinal axis; and, means adjacent said inlet bores at said peripheral surface for exerting a positive scooping effect to move coolant along said surface towards said inlet bores so that coolant is drawn from said surface through said inlet bores and towards said longitudinal axis, said exerting means formed such that each of said inlet bores includes a channel partially extending circumferentially about said peripheral surface and having a first end which merges into the respective of said two or more of said inlet bores and a second end spaced from said first end in the direction of intended rotation of said extension member, each channel being scoop-like in configuration and having a leading edge which forms said second end.