Patent GB-1400731-A (GB)
Title: Machine tool comprising automatic tool changing means
IPC: B23Q16/10
Filed: 1972-06-15
Abstract: 1400731 Machine tool details EX-CELL-O CORP 15 June 1972 [28 July 1971] 28035/72 Heading B3B A machine tool comprises (a) a tool spindle assembly 12 including a rotatable tool spindle 43 operatively mounted for movement along a first axis; (b) a work-table 17; (c) means for operatively mounting the work-table adjacent said tool spindle for movement along two axes which are perpendicular to each other and to said first axis; (d) a tool storage means 13 spaced from the spindle 43 and adapted to move a tool into a tool change position with the axis of the tool parallel to the axis of the spindle; (e) a tool changer means 14 for transferring tools directly between said tool storage means and said tool spindle; (f) a column assembly comprising a pair of laterally spaced column members 22, 23 carried on a base 10 and supporting said spindle assembly for movement along said first axis; (g) said tool storage means being mounted on said column members 22, 23 above the spindle assembly, and comprising (1) a horizontally disposed endless conveyer 166 including a plurality of tool pots 169 hingedly connected together by vertically disposed pins; (2) means for moving the conveyer 166 in a predetermined sequence of movement for coaction with said tool changer means 14 for transferring tools; (3) said tool pots 169 releasably holding a tool holder 144 on a horizontal axis; (4) each of said tool pots 169 is provided with means for indicating that a tool holder is mounted in said pots; and (5) said indicating means in said pots comprising a vertically disposed pin slidably mounted in each pot and movable downwardly by gravity if a tool pot is vacant and movably upwardly when a tool holder is inserted into a tool pot (Fig. 16, not shown). Machine tool details.-A saddle 16 is movable in the X axis on ways (400), (401) (Fig. 43, not shown) which are constructed within the saddle 16 assembly and bolted and keyed to the base 10. The saddle is moved by an electric motor driven lead screw with a position measuring resolver. The work-table 17 is carried on a casting 444 (Fig. 53) (which constitutes the saddle 16) and is moved in the Z axis by a similar lead screw drive with a position resolver, along similarly provided ways. The spindle assembly 12 is movable vertically between the columns 22, 23 on removable ways (33) (Fig. 5, not shown) by an electric motor driven lead screw. Pairs of switches and operating abutments act to limit the movement of the spindle assembly 12. The weight of the spindle assembly is counterbalanced by weights (Fig. 9, not shown). The spindle 43 is driven by an electric motor 103 (Fig. 11) through a gear and clutch arrangement to provide 1 : 1, 3 : 1 or 9 : 1 drive ratios. The rotational position of the spindle 43 is sensed by a resolver 134. A tool holder 144 is held in the spindle 43 by a draw bar 141 which has a screw thread connection with the tool holder. The draw bar is rotated in either direction by an hydraulic motor 159 driving through a clutch 158. The draw bar is tightened until a pressure rise in the hydraulic system operates a pressure cut-out, whereupon the clutch locks the draw bar. Tool changers.-Tools are stored in a conveyer storage means (Fig. 15) in the predetermined order of use, in the tool pots 169 which are linked together by pins 170 to form a chain conveyer which passes over a drive sprocket 178 at the tool change position, and two idler sprockets 179, 180. The pins 170 are guided between guides 224 between the sprockets. A tool holder is retained in a pot 169 by spring detents that engage in a groove in the tool holder. The conveyer includes a plunger and switch means 249 to indicate whether a tool is present in a pot at the tool change position. A tool change means comprises a rotatable arm 258 having a pair of tool grippers 261, 262 spring 280 biased to grip a tool and fluid pressure operated to release it. The arm is rotated 90 degrees from a parked horizontal position to engage tools in the spindle and tool change position of the conveyer, and rotated 180 degrees to effect a tool exchanger. The arm 258 is mounted on the end of a shaft and the shaft is movable axially to enable the arm to extract and insert tools from and to the spindle and tool conveyer. The shaft is rotated and moved axially by fluid pressure means. Rotary table indexing.-The work-table 17 is rotatable by an electric drive motor driving a worm 472 (Fig. 53) which engage a wormwheel 465. A pair of cams on a flange 478 engage switches to provide four positions for the table 17. At the outer periphery is provided a pair of interengaging toothed rings 452, 454 to fixedly locate the table in its indexed position. A spring pack 462a keeps the rings 452, 454 biased together and fluid pressure means are provided to raise the table 17 to disengage the rings. A set of pins 499 having conical faces that locate in conical recesses 469 act to eliminate back lash during an indexing operation.