GB897809A - An improved method and apparatus for quench hardening - Google Patents

Abstract

897,809. Press quenching. GLEASON WORKS. Jan. 14, 1959 [Jan. 24, 1958], No. 1394/59. Class 72. A method of quench hardening a ring gear or like part comprises applying quenching medium to the heated part while it is held between clamping dies, the clamping pressure exerted on the part by the dies being periodically released as the part is cooled. As shown, a quench press comprises a press frame 26 slidable on rods 22 and 23. Rotation of cranks 35 through 180 degrees lowers die carrier 39 on to a workpiece such as ring gear G which is supported on lower dies on press frame 26. Similar rotation of cranks 28 lowers press frame 26 to carry the workpiece below the level of the quenching liquid. Die carrier 39 comprises a central cylinder 42 and piston 43 which actuate centering device 46, six cylinders 48 arranged in a circle around cylinder 43 with pistons 49 connected to an annular die member 52 which is adapted to bear on the inner portion of the upper face of the workpiece, and six concentric cylinders 59 with pistons 58 connected to annular die member 54. The reaction of the thrust applied to the workpiece is transmitted by screw 41 to tongues 67 which are locked below corresponding tongues 73 by the movement of lock bar 72. The lower die (Fig. 8) comprises concentric outer and inner annular members 87 and 88 which support radially disposed bars 89 on which rests the workpiece, member 87 being fixed at 88 and movable up and down by piston rod 94 attached to piston sections 96 and 97 by threads 95 of opposite hand, rotation of rod 104 with respect to these sections varying their spacing and hence the maximum length of the piston stroke. Alternate application of hydraulic pressure through passage 109 to cylinder 98 and through ports 62 to cylinders 48 rocks bars 89 about fulcrum 87 and flexes the workpiece 20-120 times per minute to the extent of 20-40 thousandths of an inch prior to quenching, the number of flexures being automatically controlled. The position of annular member 88 and assembly 96 is fixed when quenching by a stop means comprising a ring 112 rotatable around part 93 and having inclined surfaces engaging complementary inclined surfaces on another ring secured to part 93 so that rotation of ring 112 by piston 116 as far as it is allowed by preset eccentric 125 determines the angle of bars 89 when quenching. When the frame is lowered into the quench tank coolant is circulated by a pump through pipes 132 into chamber 135 through openings 136, groove 139, some flowing under the workpiece between bars 89 and out through passages 144 to the quench tank, while the remainder flows over the teeth of the workpiece to chamber 146 and returns to the quenching tank through openings 147. While quenching, the high pressures exerted by die members 52 and 54 and centering device 46 are released at a rate of 20-200 pulses per minute for 10-15 seconds in the case of automobile gear rings. The hydraulic and electrical circuits are described. Specification 806,993 is referred to.