Patent GB-1261631-A (GB)
Title: Machining apparatus with automatic tool changing means
IPC: B23B31/26
Filed: 1969-01-21
Abstract: 1,261,631. Tool changing mechanism. EXCELL-O CORP. 21 Jan., 1969 [5 Feb., 1968], No. 3325/69., Headings B3B, B3C, B3K and B3T. A machine tool having a vertically movable horizontal spindle 12 and a horizontally movable and indexable work-table 11 includes a tool storage means 13 comprising a chain conveyer 41 and tool holding means 48; a first transfer means 15 for removing a tool from, or replacing a tool in, the tool storage means 13 and a turn around means 14 for swinging a tool through 90 degrees between the first transfer means 15 and a second transfer means 16 for exchanging a tool in the spindle with one held by the turn around means. The first transfer means 15 comprises a pivoted arm 66 having gripping means at one end for gripping and locking around a peripheral groove of a tool carrier. The gripping means is locked by spring biased, hydraulically released locking plunger (84) (Fig. 3, not shown). The arm 66 is pivoted by hydraulic operated racks in a housing 76, which housing is extendable and retractable hydraulically on a slide 77 to remove a tool from the holding means 48 and place it in a pot 95 of the turn around means 14, or viceversa. The turn around means 14 comprises an hydraulically swingable bracket which carries the pot 95 and enables the tool to be presented parallel to the spindle 12 and adjacent the second transfer means 16. The second transfer means 16 comprises an hydraulically oscillatable arm 140 having tool gripping and locking means at each end. The arm is hydraulically extendable and retractable on a slide 153 to axially remove tools from the spindle 12 and pot 95 before rotating the arm 140 to exchange tools. The machine is automatically numerically controlled by electrohydraulic devices and circuits (Figs. 8 and 9, not shown). A machine programme may be interrupted to manually load an extra long tool into the pot 95. The machine may be used for milling, drilling, boring and tapping. Beds and frames.-The machine comprises a rear base 38 supporting a column 37 along which the spindle 12 is vertically movable by means of a drive shaft extending from a housing 40. A front base 29 supports slide-ways 27 for a horizontally movable carriage 26, which in turn has slide-ways 25 along which a carriage 24 is slidable perpendicular to the carriage 26. An indexable work-table 18, 19 supports a workpiece 10. The vertically movable spindle is hydraulically counterbalanced by piston and cylinders, shafts and cables etc. (163)-(174) (Fig. 8, not shown). The spindle head includes pipes, and passageways (191), (192) (Fig. 6, not shown) for lubricating a spindle thrust bearing. Chuck operating mechanisms.-Each tool is held in a tool holder (81) (Fig. 6, not shown) having a conical shank (119) that mates with a conical socket 203 in a spindle tube (117). The end of the holder (81) includes a splined end that engages with an internally splined sleeve (205) which passes over the splines of the holder (81) and is rotated to lock the splines behind each other and which is then drawn into the spindle to clamp the tool holder (81) into the spindle. A driving key (197) ensures positive drive of the tool. The sleeve (205) is rotated to lock the splines by an axial movement of a spring biased draw bar 210 acting through helical gearing (208) (209). The tool is released by supplying hydraulic pressure fluid to a sleeve piston (230) surrounding the spindle. The tool is ejected by an end cap (211) of the sleeve (205). Machine tool details.-The spindle is rotated hydraulically by means (243)-(246) (Fig. 8, not shown) after a machining operation to position the spindle for a tool change. The indexable table 18, 19 is raised before indexing and a transducer emits a signal for every 0À1 degree of table rotation. The rotation is numerically controlled to be lowered and clamped in any one of 360 discrete positions. The spindle head includes piping (196) and passageways (193)-(195) for blowing air outwards from the spindle during a tool change to clean the tool-holder (81) and prevent swarf entering the conical socket (203). The various tables and slides are moved by electric motor driven lead screws.