Patent GB-1012193-A (GB)
Title: Automatic tool changing
IPC: B23Q3/157
Filed: 1964-02-10
Abstract: 1,012,193. Machine tool details. CINCINNATI MILLING MACHINE CO. Feb. 10, 1964, No. 5421/64. Headings B3B and B3K. [Also in Division G3] A machine tool comprises an indexable tool storage means 73 (Figs. 1 and 2), a single arm 115 for moving a tool from the storage means to a pick-up position, and a double arm 145 for moving the tool from the pick-up position to the machine tool spindle 29. In a milling machine, a tool column 24 is traversed on a bed 21 by an hydraulic motor 26 and a screw 25. The spindle 29 is rotated by an hydraulic motor MF2 on a head 28 adjusted vertically by a third hydraulic motor MF1. A further hydraulic motor 35 traverses a work-table 33 to-and-from the spindle. Chucks.-The tools are each mounted in a holder 57, Fig. 14. The holder is secured in the spindle 29 by a threaded draw-bar 56 operated by a reversible-electric motor, a bellows-type gripping sleeve 60 and driving teeth 65. In the storage drum 73, Figs. 6 and 7b, each tool holder 57 rests with its groove 72 engaging a recess in a drum-plate 79. Each tool is retained by an over-centre latch 97 released by a handle 100, when tool-changing is under manual control, or by a bevelled rod 106 engaging an arm 107. The latch is automatically re-engaged when a tool is deposited in the drum. Each tool is identified by a key 112 co-operating with reading heads 111. A tool is picked up from the drum by the arm 115, Fig. 3, which has a semi-cylindrical recess 125 closed by the spring-pressed rod 106. When the arm is rotated clockwise with a tool therein, it is halted when a stop 134 engages a piston 140. At the required time, it is subsequently lowered to the interchange position by retracting the piston 140. When a tool is returned to the drum, the rod 106 is released by a piston 132 moving a plunger 131 to rotate rack gearing 127. The piston 132 then raises the arm to clear the drum. The double arm 145 for transposing the tool in the spindle with a new tool from the arm 115 is rotated by an hydraulic motor and is moved axially to mid, and fully extended, positions by two independent hydraulic rams. One of the rams operates a switch by way of a plunger passing through a seal in the cylinder. The tools are gripped in sockets in the arm 145, Fig. 10, by rods 190, 191 which can be retracted by a cam- and lever-operated rod positioned on the axis of arm rotation. The tool drum is rotated by an hydraulic motor which also rotates a recessed cam to co-operate with an hydraulic control device each time the drum rotates by the angle separating tool positions. Speed-controlling; brakes.-When it is desired to stop the drum, the hydraulic control device is actuated and a plunger moves down into the recess gradually to cut off pressure supply to the hydraulic motor. In case of pressure failure, the carrier 28 is prevented from dropping by a spring-applied brake. To assist in engaging a new tool with the driving teeth 65 on the spindle, the latter can be rotated at a low speed. Programmed electric control.-When the machine is controlled by a tape 390, Fig. 17, after a tool has been selected and is in the waiting position, the drum 73 is rotated to the correct position to receive the old tool. The spindle carrier 28 is moved to a tool-change position, when a new tool is required, by a control including a potentiometer and a torque motor. The circuits include a four-bank stepping switch to initiate operations and to receive signals concerning operations completed. Stepping-switches are also used in means 393, 394 to store the identification numbers of the tool in the spindle and the tool next-to-be-used, so that a tool is replaced in its particular drumlocation and the correct tool is placed in the spindle. Reference has been directed by the Comptroller to Specification 922,167.