Patent ID: 9144847
Filing Date: 2015-09-29
Classification: B23B,Y10T

Abstract:
1. A cutter assembly comprising: an adapter having two ends a connecting rod formed on one end of the adapter; an inserting hole defined in the other end of the adapter opposite to the connecting rod; a sleeve segment formed around the inserting hole and having an outer surface; a guiding slot defined in the outer surface of the sleeve segment and comprising a limiting segment formed laterally in the outer surface of the sleeve segment; and a sliding segment formed longitudinally in the outer surface of the sleeve segment and connected and communicating with the limiting segment; multiple ball holes defined through the outer surface of the sleeve segment and communicating with the inserting hole, and each ball hole being conical and having a minimum diameter; multiple balls mounted respectively in the ball holes, and each ball having a maximum diameter larger than the minimum diameter of a corresponding one of the ball holes; and at least one holding tab formed on and protruding from the adapter at the end in which the inserting hole is defined; an outer collar slidably and rotatably mounted around the sleeve segment of the adapter and having an inner surface; an annular protrusion formed on and protruding from the inner surface of the outer collar and selectively abutting against the balls; an annular escaping recess formed in the inner surface of the outer collar adjacent to the annular protrusion and selectively aligning with the ball holes; and a positioning rod mounted on the outer collar and extending slidably into the guiding slot; a recoil spring mounted between the adapter and the outer collar and mounted around the sleeve segment of the adapter; a holding ring mounted around the sleeve segment of the adapter and abutting the outer collar to hold the outer collar on the sleeve segment of the adapter; and a head mounted detachably on the adapter and comprising two ends; a saw formed around one of the ends of the head; and an inserting rod formed on and protruding from the other end of the head, inserted into the inserting hole in the adapter and having an annular engaging groove formed around the inserting rod at a position corresponding to the balls to selectively hold the balls in the engaging groove; and at least one holding surface formed on the inserting rod and abutting respectively the at least one holding tab on the adapter, wherein the inserting hole and the inserting rod on the head are round in cross section; the adapter further has a central hole defined in the adapter and co-axially communicating with the inserting hole; the head further has a central through hole defined axially through the head; a central drill is mounted through the central through hole in the head and extends into the central hole in the adapter via the inserting hole; and the cutter assembly further comprises a pushing assembly mounted between the adapter and the head and comprising a pushing block mounted moveably in the inserting hole, abutting the head, and having a central hole defined through the pushing block, wherein the central drill is mounted through the central hole of the pushing block; a pushing spring mounted around the central drill and having two ends abutting respectively the adapter and the pushing block; and a limiting ring mounted the inserting around the pushing block to provide a limiting effect to a movement range of the pushing block.