Patent GB-435831-A (GB)
Title: Improved method of and apparatus for the surface hardening of metal articles, particularly gear wheels
IPC: C21D9/32
Filed: 1934-10-17
Abstract: 435,831. Hydraulic transmission of power. GLEASON WORKS, 1000, University Avenue, Rochester, New York, U.S.A. Oct. 17, 1934, No. 29734. Convention date, Aug. 4. [Class 69 (ii)] [See also Groups II and XI] In a method of hardening the surfaces of metal articles, particularly gear wheels, by means of a burner, the flame of the burner is traversed across the surface of the gear to preheat the surface and then immediately traversed in the opposite direction to heat the surface up to the hardening temperature, the preheating traverse being done at a higher speed than the hardening traverse. The surface is quenched immediately after being raised to the hardening temperature. The burners 40, 41 are secured to the ends of gas pipes 42, 43 mounted in blocks 44, 45 and connected by flexible pipes 46, 47 to a supply pipe 48. A reciprocating ram 70 is connected by a pin 88 to the end of a piston rod 86 secured to the end of a piston 85 which moves in a cylinder 84. A slotted plate 89 is connected to a reciprocating ram 70, moving with the latter, and is provided with a slot 92 in which is adjustably mounted a trip leg 90. A cam bar 94 is pivoted at 95 to a plate 89 and is angularly adjustable by means of a nut 96 which passes through an arcuate slot 97 and is carried by a bolt secured to the plate 89. The end of the bar 94 is graduated to read against a zero mark on a lug 98 secured to the plate 89. A reversing valve 101 is provided with a supply pipe 200 and an exhaust pipe 203 and is connected by pipes 201, 204 with the cylinder 84, another pipe 205 also connecting the casing 100 with throttle valves 103, 104 which control the speed of the burners during the hardening stroke of the latter. The valve 103 is provided with a stem connected to a rod 106 provided at its outer end with a roller 108 which contacts with the lower part of the cam bar 94. The roller 108 is held in position by a spring 109 inside the valve 103 which is provided with an inlet port 115 connected to the part 205<a> of the pipe 205 and an outlet port 116 connected by a pipe 207 to a sump. The valve 103 is also provided with cylindrical glands 117, 118 and a bevelled portion 119 merging into the part 118, the part 119 controlling the area of the opening 115 and thus controlling the movement of the piston 85 being in turn itself controlled by the setting and shape of the cam bar 94. The valve 104, of similar construction to the valve 103 controls the speed of the piston 84 during the hardening stroke of the burners independently of the valve 103 but the area of the opening of the port 129 connected to the pipe 205b is controlled by a hand nut 134. The valve 101 is moved in one direction by a spring 140 and in the other direction by a handle 144 which is pivoted at 145 on a lug 146 integral with the cylinder 84. The valve 101 may be locked in a position to which it has moved manually by the engagement of a lug 150 on the handle 144 with a spring-controlled dog 151 pivotally mounted on a lug 152 secured to the housing 100 of the valve 101. The valve 104 is adjusted to determine the basic speed of the burners on the hardening stroke and the bar 94 is angularly adjusted to determine the variation of the traversing speed of the burners during that stroke. The dog 90 is adjusted along the slot 92 to govern the length of the stroke of the head 70 according to the length of the tooth. The operator now moves the handle 144 from right to left, where it is locked in position by the engagement of the dog 151 with the lug 150. Liquid from the pipe 200 flows into the valve 101 and thence by the pipe 201 into the cylinder 84 moving the piston 85 to the right and thus the burners over the surface of the tooth to preheat the same, the burners being moved apart during their movement owing to the setting of the bars 163, 164. Towards the end of the preheating traverse of the piston 85, the trip dog 90 engages the dog 151, swinging the latter about its pivot to release the handle 144. The spring 140 moves the valve to the right allowing fluid from the pipe 200 to flow into the valve and thence by the duct 202 into the right hand end of the cylinder 84. The movement of the piston 85 to the left will be comparatively slow because the fluid in the cylinder 84 must exhaust through the valves 103, 104. With the setting of the bar 94, the speed of travel of the burners will accelerate as the piston 85 moves to the left and when the piston 85 reaches the end of its stroke, the forward movement of the burners stops.