Patent GB-1075803-A (GB)
Title: Automatic tool changing apparatus
IPC: B23Q3/157
Filed: 1963-12-31
Abstract: 1,075,803. Tool-changing. O. EVANS (Giddings & Lewis Machine Tool Co.). Dec. 31, 1963, No. 51453/63. Headings B3B, B3C, B3K and B3T. [Also in Division G3] A machine tool such as a boring, drilling, tapping and milling machine, comprises a tool storage drum 20 mounted on a horizontal axis and carried rearwardly of a horizontal power-driven tool spindle 14, and a tool transfer means 27 for carrying a tool from the drum horizontally to a position laterally adjacent the spindle and then along a vertical path to the spindle. The work is carried on a table 11 traversable on ways 10<SP>11</SP> on a carriage movable on ways 10<SP>1</SP>. The spindle 14 is carried in a vertically-movable head 13. The drum 20 is carried on two idler wheels 23 and is rotated by a sprocket wheel 25 driven by the drive for the spindle 14. The transfer means 27 comprises heads 30, 31 having arms 35, 36 adjustable in length and movable independently along a track 33, Fig. 3. Each tool is mounted in an adapter 53, Fig. 5, having a cross-shaped flange 67, the peripheral grooves of which are engaged by a transfer arm and the axial grooves of which engage driving dogs on the machine spindle when the adapter is secured by a screw-threaded draw-bar 74, Fig. 3, engaging a screwed recess 72<SP>1</SP>. A similar drawbar 75, Fig. 4 (not shown), in each drum socket holds the adapter therein. The draw-bar 74 is rotated by the spindle motor which also rotates the draw-bar 75 at the selected tool station by a friction drive connected by an electric clutch to a plate on the draw-bar. The front part of the track 33, Fig. 3, is indexable by a drive A. 34, 91 to interchange the positions of the transfer arms so that the upper arm may be traversed backwards to replace a used tool into the drum. The adapter holding portion of each arm, such as 36, Figs. 3 and 12, is movable, when in its forward position, by a rack rod 95 moved by rack-and-pinion gearing through the spindle drive, a screw 107, an elongated nut 111 and a lug 111<SP>1</SP>. When in its rearward position, the arm is adjusted by a screw 110 and a lug 112<SP>1</SP>. A clutch 93, Fig. 13a (not shown, prevents backward movement of the rack-and-pinion arm drive mechanism. An adapter is gripped in the arm 36 by L-shaped fingers 118 operated by springs 122 and having lugs 121, 121<SP>1</SP> engaging the adapter. The fingers are released by a rod 124 moved upwardly by toggle linkage actuated by the rod 95. (In a modification, a rod projects forwardly from one side of the arm to engage a corner of an adapter flange to rotate it if it is wrongly positioned for engagement by the L- shaped fingers). When a tool T has been ejected from the spindle 14 by rotation of the draw-bar, the head 31 is moved to clear the adapter from the spindle by a rod 138 which forms an elongated nut moved axially by a screw 137. When a transfer has been completed, the heads 30, 31 may be held withdrawn against the track 33. In summary, a tool is extracted by an arm from the drum, traversed to the front of the track 33, is rotated to position it in front of the spindle, is moved into the spindle, and the arm is then retracted to a rest position. Subsequently, the arm is again extended to pick up the tool and withdraw it, and the arm is then swung back to the upper position and the tool is returned backwards to the drum. Each tool is identified by grooves 140, Fig. 5, formed in the shank 52 which is slightly relieved in its central conical portion. In each drum socket 41, a series of spring-pressed pins engage the grooves or " no-grooves " and the positions of the pins are read by switches 150A-P, Fig. 8 (not shown), actuated by swinging bars 151 which are depressed in various combinations as the storage drum is rotated past the reading station. When a correct tool is located, an electric clutch in the drive to the drum is de-energized, and a brake applied. The tool to be selected may be identified on a punched card or tape or a magnetic tape.