GB560674A - Improvements in automatic milling machines for cutting racks or like grooved workpieces - Google Patents

Abstract

560,674. Cutting toothed racks. SCHAERER, O. Sept. 25, 1942, No. 13507. [A Specification was laid open to inspection under Sect. 91 on April 5, 1943.] [Class 83 (iii)] A machine for milling racks or like grooved workpieces has a stationary work-table or bed 1 preferably integral with the machine bed while the cutterslide moves transversely across a longitudinal carriage 2 bridging the table and guided at opposite sides thereof. The work-bed has three parallel guideways and the carriage 2 carries a member 4 vertically adjustable by a screw 5. The cutter slide 3 is guided horizontally on the member 4 and carries a ball-bearing cutter-spindle 6. The slide 3 is reciprocated to cut grooves in the stationary work on the bed by means of a reversing screw 33. The machine is driven from a motor 16 mounted on a gear-box 15 secured to the carriage. The motor drives a shaft 20 connected by change gears 21<1> and gears 24 to a shaft 23 which passes into a gear box 14 secured to the member 4. A worm 25 on shaft 23 drives a shaft 13 which through worm gearing and double spur gears drives the cutter-spindle. The shaft 13 is also connected through screw gears 28, shaft 29, change gears 30, 30<1> and shaft 31 to a wormwheel 34 loose on the screw 33. For. the return movement of the cutter slide a shaft 17 constantly driven from motor 16 is connected to a loose worm-wheel 35, the two worm-wheels being selectively clutched to the shaft 33 by a clutch member 37 operated by a fork 38 controlled by a cam 42 connected to a dividing- plate 43 and plate- 44. The wheel 35 also drives a shaft 40 carrying a ratchet wheel 41. The plate 43 has a notch coacting with interconnected levers 45, 46, each lever having a projection one of which locks the plate 43 and cam 42 after each half revolution. The plate 44 has two notches at 180‹ coacting with a lever 47 to prevent backward movement of the index plate. The plate 43 carries a pawl lever 48 normally held clear of the rotating ratchet wheel 41 against the pressure of a spring 49 by one of the levers 45, 46. The levers 45, 46 are alternately released at opposite ends of the cutter travel by a bracket 56 coacting with stops 79, 80 on a rod 55 connected by lever mechanism to the link 50. After each forward and return movement of the cutter slide the cam 42 momentarily operates a switch to energise a solenoid 74 controlling the spacing mechanism operating on the carriage 2. This mechanism is actuated from a separate. motor 65, Fig. 10, which constantly drives a gear 63 and ratchet wheel 64 loose on a shaft 62 connected through change gears 78 with the carriage screw 60. The shaft 62 carries a dividing-plate 67 and plate 72 coacting respectively with notched levers 70, 71. The plate 67 carries a pawl 68 normally held away from the rotating ratchet-wheel by the lever 70. On completion of the cutter-return the rod 75 withdraws lever 70 and the shaft 62 makes one revolution thus rotating the shaft 60 to space the cutter slide for cutting the next tooth. In a modification the cutter carriage may be angularly adjustable on a support which moves on the ways of the table 1 so that skew racks may be cut.