Patent GB-767539-A (GB)
Title: Improvements in or relating to coordinate drilling and milling machines
IPC: B23Q3/16
Filed: 1954-07-30
Abstract: 767,539. Drilling-machines; chucks; milling- machines. BERLINER MA SCHINENBAS AKT.-GES. VORM. L. SCHWARTZKOPFF. July 30, 1954 [Aug. 28, 1953; Nov. 3, 1953], No. 22371/54. Class 83 (3). A co-ordinate drilling and milling-machine comprises end measuring gauges in drums 9-11, Fig. 2, associated with pre-selecting means operable only when the tool splindle slide 1 is in a predetermined position. The tool is clamped in a spindle 61, Fig. 9, by a cone 80 secured against rotation by dogs 82. The cone is moved axially to clamp or unclamp by a rod 78 screwing into the cone and rotated by a reversible motor 75, controlled by buttons 158, 159. The motor drives through a clutch 74, 74<SP>1</SP>, which is engaged on upward movement of the spindle, and through a clutch 76 which slips at the required tightening torque. The spindle 61 is rotated by a motor 62 through variablespeed gearing 63 and a belt pulley 64 which drives the spindle direct or through gearing 73 according to which of two electrically-operated clutches 65, 66 is engaged. The motor 62 is started by buttons 162 or 163 and stopped by a button 167. The speeds of the gear-boxes 63, 68 are set by knobs 160, 161, Fig. 18. Pressure on these knobs then actuates electromagnetic clutches to render the set speeds operative. The spindle-sleeve 72 is moved at feed-rate by the spindle-motor 62 through gearing 67-71, or at a fast-rate by a reversible-pole motor 83 driving through gearing 86, an electrically-operated clutch 87 then being disengaged. The motor 83 is controlled by a hand-lever 88, Fig. 10, which moves the motor-brushes 89, 90 to give a fast upward speed or a variable-speed downward feed. The hand-lever also operates switches 94, 95 which respectively operate the solenoid 96 of a brake 97 and the clutch 87. Switches 99b, 100 stop the feed and return at the limits of spindle-travel. The spindle may be fed by a hand wheel 101, Fig. 9, in which case a switch 102 is actuated to energize the solenoid 96 and release the brake 97. The spindle-speed is set by a knob 105, Fig. 11, which turns a notched disc 109, associated with speed-setting switches and engaged by a switchactuating plunger 116, the set-position being indicated by a truslucent dial 108<SP>1</SP> and marker 114, the dial being illuminated by a bulb 113 when the knob is depressed to connect contacts 120, 120<SP>1</SP> by an insulated metal ring 119. The spindle-feed is set by a knob 122, Fig. 18, which clamps a free vernier-scale 127 in any position, the feed being stopped by a projection on the scale operating the switch 100 to disengage the clutch 87 and engage the brake 97. The position of the spindle is indicated at any moment by a pointer 140. The spindle-sleeveassembly is balanced by spiral springs acting through a cam 141, Fig. 9, designed to give a constant balancing-force. A switch 151 is actuated when the sleeve 72 is in its uppermost position to render effective the button 60 for initiating movement of the slide 1 and a similar button for slide 2. However, if the machine is to be used for milling, and the carriagesetting devices are therefore not required, the spindle-sleeve is clamped by a knob 152, Fig. 18, which also actuates a switch 153, Fig. 9, to bridge the switch 151. The clutch 87 can be actuated at any time by a button 164 or 165 and all the clutches can be rendered inoperative by a button 166 to allow the spindle to be moved freely by hand. A transparent screen and neon tube in the top of the spindle-housing enable the engagement of tool and work to be observed. Framings. A recess 5, Fig. 1, in the machine frame gives access to the rear side of the worktable. Operation. The appropriate three gauges are selected by three hand-set levers on discs set in a panel 26, Fig. 1, and each carrying contacts O-IX, Fig. 2, to energize appropriate ones of three sets of electromagnets 23, 24, 25, each controlling a dog 42. When the pushbutton 60 is pressed, an electromagnet 18 is energized to operate a valve 17 and so move the slide 1 to its retracted position. Retraction of the slide withdraws a stop rod 13 to allow all the gauges to be returned to their zero positions by springs 51. Movement of the gauges releases a spring-pressed rod 39 to actuate a switch to complete a circuit containing a sliding contact 37 moving with the slide 1. The contact 37 engages contacts O<SP>1</SP>-IX<SP>1</SP> which correspond to contacts O-IX of drum 11 to avoid unnecessary movement of the slide 1. When the contact 37 engages whichever of contacts O<SP>1</SP>-IX<SP>1</SP> has been pre-set, an electromagnet is energized temporarily to release a series of drum-locking stops 49, 49<SP>1</SP>, 49<SP>11</SP> on a rod 50. Furthermore, the electromagnet 18 is actuated to move the valve 17 to stop the slide 1 and a motor 20 is started to rotate the drums to zero position. The drums are checked in their zero positions by dogs operating switches in parallel, to stop the motor when all are in position, and also operating switches in series to start the motor in reverse. The drums now rotate until checked by the appropriate pre-set dogs 42. When checked, a portion of each drum is still carried round until one of the stops 49, 49<SP>1</SP>, 49<SP>11</SP> can enter aligned recesses in the drum. Until all the stops 49 have engaged recesses, the rod 50 cannot be released to actuate a switch to stop the motor 20 and set the valve 17 for operative travel of the slide 1. When the slide approaches the end of its travel, the stop rod 13 is pressed rearwardly to operate a valve 57 which gradually slows the speed of the slide. The slide is momentarily stopped just before its final position while pressure is built-up in front of the piston 19 to push the gauge-bars together. The second slide 2, Fig. 1, on the slide 1 is then positioned in a similar manner by controls on a panel 26<SP>1</SP>. While a hole is then drilled or reamed the next positions of the slides are pre-set. The tool is retracted rapidly by pressure on a button 154. Near the end of the travel of the sleeve 72 a switch 98, Fig. 9, is actuated to stop the motor 62 and, when the switch 151 is opened, the rapidmotion motor 83 is also stopped and the brakesolenoid 96 is released.