Patent GB-474281-A (GB)
Title: Improvements in or relating to the method of and machines for finishing gears
IPC: B23F5/20
Filed: 1936-01-25
Abstract: 474,281. Gear-cutting. NATIONAL BROACH & MACHINE CO. Jan. 25, 1936, No. 26156/37. Convention date, Jan. 26, 1935. Divided out of 474,227. [Class 83 (iii)] In a method of and machine for finishing gears by mating the gear to be finished with a rotary cutter gear provided with grooves forming cutting edges and having teeth of such helix angle that when in correct mesh with the blank, the axes of the cutter and blank are crossed at an angle between 3‹ and 30‹, the work and cutter axes are relatively reciprocated to spread the cutting action over the tooth faces of the gear to be finished and the axes are automatically fed towards each other periodically by predetermined increments until the required amount of metal has been removed. A head 105 has a bearing part 107 and swivels about a vertical axis on the frame portion 104, being secured after adjustment by studs 111. A motor 113 in the head drives through reduction gearing 114 a shaft 115, connected by gears 117, shaft 116 and bevel gears 127 to a horizontal spindle 123 carrying the cutter 130. The cutter spindle is mounted in bearings 121, 125 and the cutter is secured against a collar 129 by a nut 131 carried by a spindle 132 mounted in a bearing 122. The work table 133 is vertically adjustable on ways 134 and a bracket on the table carries a reversing electric motor 136 which is connected through reduction gearing 137, shaft 139, and other gearing to the screw 146 which imparts reciprocating movement to the work slide 149. The reversal of the motor is effected automatically by stops 155 on the table coacting with a lever 154 and reversing switch. Vertical adjustment of the table is effected from a hand wheel 161 connected through bevel gearing 164 to a vertical screw 165. For automatic upward feed of the table towards the cutter the shaft driving the screw 146 carries a worm driving a horizontal shaft 176, Fig. 6, projecting into a feed box 173 and connected by gears 178 to a shaft 179, Fig. 6, carrying a disc 180 provided with cam arms 181, 182. These arms coact with a roller on an oscillating lever 183 connected by a link 186 to a ratchet pawl carrier 194, the pawl 191 engaging a wheel on a shaft 172 connected by gearing to the table elevating screw. At each end of the work movement one of the arms 181, 182 engages the roller to impart a vertical feed step to the work. An adjustable arm 198 rotates with the ratchet wheel and after a predetermined feed this arm lifts the pawl 191 and stops the feed. The carriage 149 carries stocks 202, 203, for the gear blank arbor, one of the centres being axially adjustable. Start and stop buttons 208, 209, respectively, Fig. 7, control simultaneously the head motor 113, the table motor 136, and oil pump motor 212. A hand switch 213 independently controls the direction of the head motor and the automatic reversing switch 160 reverses the head and table motors simultaneously at the end of the desired work travel, the automatic depth feed being actuated just prior to reversal. After stopping of the depth feed, the action continues for a predetermined time until the automatic stop switch 214 stops all the motors. Specification 415,875 is referred to.