Patent GB-1156291-A (GB)
Title: Automatic Tool Changing Device for a Machine Tool
IPC: B23B39/20
Filed: 1966-08-31
Abstract: 1,156,291. Machine tools. ING. C. OLIVETTI & C., S.p.A. 31 Aug., 1966 [2 Sept., 1965], No. 38822/66. Headings B3B, B3C, B3N and B3T. An automatic tool changing device for a machine tool comprises a tool storage magazine 17, power means 42 conditionable for rotating the magazine in either of two directions, and a plurality of elements 44A-44L individually settable for selecting a corresponding tool, a plurality of control members 45A-45L individually connected to the elements and secured to the machine frame coaxially with the magazine in a reverse order with respect to the tools, a cam 46 secured to the magazine comprising a first position 48 to engage half but one of said plurality of members so as to cause the member connected with the element so set to condition the power means to rotate the magazine in a predetermined direction when engaged, in an opposite direction when not engaged, and a second portion 49 to engage one member at a time so as to disable the power means when the tool corresponding to the set element is located in the working station. The tool-changer drum 17 is mounted on a vertically-adjustable head (14) locked in position by a lever (16). The drum is rotated by the reversible electric motor 42 through bevel and worm gearing and through an electromagnetic clutch (34) which is held open when a switch roller 50 is engaged in a recess in a disc 55. In operation, a programmed control circuit closes a switch 44I of a selected tool to cause a circuit 47 to energize relays RX and TX. The motor 42 thus rotates the drum 17 clockwise and the clutch (34) is energized. When the cam portion 49 opens the switch 45I, and the disc 55 allows the switch 50 to open, the clutch (34) is disengaged and the drum stops. The motor 42, however, continues to rotate, so that, when a clutch 53 is engaged, a worm drive 36 causes a crank disc 54 to rotate through 180 degrees to carry the spindle sleeve 62 and the spindle 21 downwardly to engage the selected tool 20 by a taper 108 and dogs 87. A motor (119) is then started to rotate a draw-bolt 112 to lock the tool, the motor stopping when a certain torque is reached. The tool is released from the drum by actuation of a solenoid 105 which pulls a jaw 101 out of engagement with the tool, there being inter-engaging rack-and-pinion gearing for simultaneously releasing also the jaw 93. At the same time, a solenoid (127) raises a driving sleeve 117 clear of the bolt 112. Rotation of the crank disc 54 allows a spring 136 to move a bar 133 downwardly to an extent determined by a pre-set cam device 128, one of which is provided for each tool. Movement of the bar rotates gears 141, 142 to shift a rod 148 connected to a change-speed device operated by electromagnetic clutches to set the speed of rotation of a feed pinion 78. The depth of feed is determined by a pinion 66 operating a measuring transformer (71). A change-speed device controlling the toolspeed and the change-speed feed device are both de-energized when the tool return stroke is complete and the jaws 92, 93 relock the tool when it has reached a particular angular position. The tool is then unlocked from the spindle and the parts are returned to their initial positions. For threading, each cam device 128 has a separate cam portion which engages a switch 152 so that the withdrawal speed, as well as the feed-speed, is controlled.