GB1248449A - Machine tool - Google Patents

Abstract

1,248,449. Tool changing mechanism; drilling and boring machines. CINCINNATI MILLING MACHINE CO. 12 Dec., 1968 [15 Dec., 1967] No. 59173/68. Headings B3B and B3C. [Also in Division G3] A numerically controlled machine tool 10 in a manufacturing system in which workpieces are automatically supplied to a work station by conveyer means, comprises a drive spindle 18 on which are mounted tool modules 17 having a plurality of tool spindles 19 and an input driveshaft 21. The modules 17 are stored in a magazine 15 comprising a vertical stack of independently rotatable storage discs (26), (27), (28), (29) and (31) (Figs. 5 and 6, not shown), and are removed therefrom by an input transfer mechanism 13 and placed in a queue on a conveyer 22 storage mechanism 12 for feeding to the machine spindle 18. The modules 17 are pushed from the conveyer 22 by an overhead track 39 on to a platform (38) (Figs. 7 and 8, not shown) which is movable sideways to align the module with the spindle 18. At this position the module is suspended on a device (53), (Fig. 10, not shown) and supported by a vertically movable platform (64). The module is then attached to the spindle 18 and a workpiece machined. For module removal it is first detached from the spindle 18 and lowered by the platform (64) to the level of an output conveyer 23 and deposited there for sideways movement therealong. An output transfer mechanism 14 replaces the modules into empty spaces in the bulk tool magazine 15 and comprises a track 74 movable within a housing 73 to pick up a module 17. The track 74 is retracted with a module and then rotated and, by a system of over-ridable detents, the module is moved by the opposite end of the track 74 into an empty place in the magazine 15. The transfer mechanism 14 includes a vertically movable mechanism to place a module in any disc. Chucks and spindles (Figs. 26-38, not shown).-The spindle 18 includes a central shaft 89 surrounded by a spring-biased sleeve (108) operated by a pressure device (109) to release or grip a tool module by means of collet gripping fingers (106) that engage with a flange ring (104) on the module 17. Operation of the pressure device (91) to release the collet also moves rods (125), (126) that rotate a cam (148) to withdraw a detent (132) to allow the collet to be released. The end of the shaft 89 and the module include rough aligning engaging dogs (100), (101). Accurate alignment is achieved by an outer ring of engaging teeth (116), (118). The teeth (116) on the module are covered by a dirt shield (121) which is deformed as the module and spindle are pulled together. Machine control.-The machine control system (Fig. 39, not shown) includes computer control of machining information programmes on tape for each workpiece and ensures that a required tool module is at the spindle 18 for a workpiece. Once the storage magazine 15 is loaded with tool modules 17 the position of any module is memorized whether it be in the magazine, in the module queue on input conveyer 22, on the spindle 18, in the output conveyer 23, or has been moved to another position in the magazine. The control has the facility for taking a module 17 from the output conveyer 23 and placing it on to the input conveyer 22 for immediate reuse. Each tool module information record may include data relating to the length or diameter of a tool which can be used to modify positioning co-ordinates of the machine numerical control system. The Specification describes four control cycles, viz. (1) Spindle loading; (2) outgoing module to storage magazine; (3) spindle loading from incoming queue; (4) incoming queue loading from magazine. The cycles are performed one at a time and a built-in logic system assigns a priority in the order of 1, 3, 4 and 2.