Patent GB-657499-A (GB)
Title: Improvements in gear testing and lapping machines
IPC: B23F19/02
Filed: 1948-07-20
Abstract: 657,499. Lapping gears. GLEASON WORKS. July 20, 1948, No. 19462. Convention date, Feb. 3. [Class 60] [Also in Groups XIX and XXIX] A machine for lapping gears having a pair of spindles to support a pair of gears G, P and means for rotating one of the spindles to rotate the gears in mesh, is characterized in that it has means for urging one of the spindles bodily in one direction to mesh the gears without backlash, an adjustable stop for limiting the movement of the same spindle in the opposite direction to limit the amount of backlash, means for pre-setting the stop, and means for holding the spindle in the position determined by the stop. The gear G, Fig. 1, is carried by a chuck on a spindle supported in a fixed head 22, and the pinion P is similarly chucked on a spindle 35. Both sets of chucking mechanism are operated hydraulically by spring-biassed pistons, such as 44, connected with the chucks by draw bars. The spindle 35 is carried by a cradle 30, Fig. 2, pivoted on a head 21 slidable on ways 23 under the control of a hydraulic piston which has a screw-threaded connection 27 with the head. A stop 60, Fig. 2, secured to the cradle is set to a position in which there is no backlash between the pinion and gear and the cradle 30 is biassed by a spring 55 towards this position. To withdraw the cradle from this position to the position of required backlash, a piston 65, Fig. 6, is provided connected with an arm of the cradle 30 by a hydraulically actuated clamp 80 in the form of a spring-biassed piston. This piston 65 is biassed upwardly towards the zero-backlash position by a spring and has its downward movement under fluid pressure predetermined by a stop in the form of a graduated member in threaded engagement with an upper rod 92 of the piston. When the cradle 30 is in its central position it is locked by a spring- biassed lever 100, Fig. 2, engaging a ballended extension 104 secured to the cradle. This lever is held in locked position by a piston 105 under fluid pressure. The angular position of the cradle is indicated by a dial gauge 115. The hydraulic circuit for actuating the machine embodies two distributing valves 125 and 126 and a manually-operated rotary valve (not shown). When the latter is turned in one direction the head 21 is slid on its ways to a position in which the pinion P is almost in mesh with the gear G. At this point the gearteeth are aligned and a jogger valve is depressed to inch the pinion into mesh with the gear. Simultaneously with this action, piston 105 is automatically released to free the cradle 30 and the clamp 80 is closed. The pressure fluid acting on piston 65 now pivots the cradle 30 to the required backlash position and a motor 50, Fig. 1, is started to rotate the pinion spindle. The gears are now rotated either in one direction only or first in one direction and then in the other for a predetermined time at the end of which the motor is stopped and the rotary valve returned to its initial position to displace the pistons of the chucking mechanism to de-chuck the pinion and the gear and to displace the piston 105 to lock the cradle 30, the head 21 being simultaneously withdrawn to enable the pinion and the gear to be replaced. The valves 126 and 127 are both upwardly displaced in their sleeves if it is desired to operate the machine manually. To prevent the machine from being started when the valves 126 and 127 are not correctly positioned for either manual or automatic operation, a safety switch 211 is provided which is opened by a spring-biassed lever 210 if the valves are not correctly positioned. The preferred embodiment is described for lapping spiral-bevel gears, but straight-bevel, hypoid, spur and helical gears may also be lapped.