Patent GB-795678-A (GB)
Title: Improvements in or relating to machine tools
IPC: B23Q16/00
Filed: 1955-07-12
Abstract: 795,678. Drilling-machine details. OFFICINE MECCANICHE CERUTI SOC. ANON. July 12, 1955 [July 12, 1954], No. 20207/55. Class 83 (3). [Also in Group XXIV] In a machine-tool, e.g. for drilling or reaming spaced holes, means for positioning the slide 1 comprises a two-speed drive controlled by triggers 42, 44 on the slide and by an indexable stop-drum 29, contact between one of the adjustable dogs 32 on the drum and the trigger 42 slowing the speed of traverse of the slide, which is stopped when the dog encounters the trigger 44. A reversing electric motor 6 traverses the slide through a transmission which includes two clutches 19A, 15A, 19B, 15B operated by solenoids 21A, 21B, clutch 19A, 15A transmitting a high-speed drive and clutch 19B, 15B, a low-speed drive under the control of switches 34, 35, 53 in the solenoids' circuits and operated by the triggers. The switches and triggers are contained in a box 25 fixed adjustably on the slide 1 by a screw 26. For high-speed traverse, the motor 6 drives the slide-traversing screw 2 through gears 7, 10, a shaft 8, to which one half 19A of the toothed clutch 19A, 15A is connected by a pin 22 carried by the armature 20A of the solenoid 21A and slidable in a slot 23 in the shaft 8, against the pressure of a spring 24, to engage the clutch upon energization of the solenoid, and the toothed rim of the clutch part 15A which meshes with a gear 4 fixed to the traversing screw. Contact between the trigger 42 and the dog 32 displaces the trigger in its guide 43, rocks a lever 38, 40 against the pressure of a spring 41, opens switch 35, which de-energizes solenoid 21A, and closes switch 34, thus energizing solenoid 21B and engaging toothed clutch 19B, 15B to connect the slowspeed drive from motor 6 through a worm gear 11, 16, bevel gears 12, 14 and clutch 19B, 15B, the toothed part 15B of which meshes with part 15A of clutch 19A, 15A. Contact between trigger 44 and the dog 32 rocks the trigger, a limb 47 of which rocks a lever 48 against the pressure of a spring 50, to open switch 53 against the pressure of a spring 52, thus deenergizing solenoid 21B and stopping traverse of the slide. The dogs 32, mounted in flutes in the drum 29, are adjusted with the aid of micrometer screws 33, between the two parts 31, 32 of the dogs, and a dial indicator 46 which cooperates with a further limb of the trigger 44 and indicates the opening of switch 53 which stops movement of the slide. After a hole has been drilled, the motor 6 is reversed and solenoid 21A energized by any conventional means, thus withdrawing the slide until a stopping device (not shown) is reached, which again reverses the motor to position the slide for the next hole to be drilled. The stop-drum 29 is also indexed for the next hole. In a modification, Fig. 2, the triggers 42<SP>1</SP>, 60 operate the switches 34, 35, 53 through levers 38<SP>1</SP>, 57, and the drive from the motor is transmitted through friction clutches 54A, 55A, 54B, 55B operated by fluid-pressure controlled by the solenoids 21A, 21B, which operate valves 56. The clutch parts 54A, 54B are urged by springs into cylinders for the pressure fluid and keyed to the shafts 81, 9<SP>1</SP> respectively.