Patent GB-584791-A (GB)
Title: Improvements in or relating to the surface hardening of metal articles
IPC: C21D1/08
Filed: 1943-08-09
Abstract: 584,791. Surface-hardening metal articles. SHORTER PROCESS CO., Ltd., and SHORTER, A. E. Aug. 9, 1943, No. 12827. Addition to 572,930. [Class 72] In the surface-hardening of metal articles as set out in Claim 1 of the parent Specification, the article is mounted to rotate about a fixed axis located centrally of the surface to be hardened and a source of high temperature heat is moved into juxtaposition with the surface and is adapted to heat the surface of several parts simultaneously, the article then being rotated about the axis at such a speed that the whole of the annular surface zone is heated to a predetermined temperature, the heated surface then being cooled to harden it. The article is placed, with the annular surface S to be hardened uppermost, on a jig J carried by a shaft mounted in bearings 12 on a frame F and driven by a motor 16. The heattreating unit H as described and claimed in Specification 584,808 comprises a nozzle-type burner with a row of annular nozzles N and concentric annular quenching units Q whose orifices O are mutually inclined towards the surface S. A mixture of oxygen and a fuel gas, such as acetylene, is fed to the burner B by pipes 18 leading from a distributing member D provided with a passage 14 connected to a mixing chamber 20 fed from flexible supply pipes 21, 22 both connected through solenoidoperated valves 23, 24 operated periodically by relays controlled by a timing device. The quenching units Q are supplied by pipes 28 from a chamber in the member D from an inlet connected through flexible tubes 31, pipe 32, solenoid-operated valves 33 and a pipe 34 to a source of quenching fluid. The distributing member D for supplying the burners is supported by a cantilever arm 42 integral with a traversing carrier 43 mounted on a pillar 44 secured on a pedestal 45 secured to the frame F. The carrier 43 is provided internally with a nut engaging a screw 47 extending centrally through the pillar 44, and connected by a coupling 48 and reduction gear 49 to a motor 50 mounted on a frame 51 supported on the pillar 44. The energising circuit for the motor 50 includes limit switches 54, 55, arranged so that when the switch 54 is turned on the motor 50 rotates the screw 47 to move the unit H towards the work while when the switch 55 is turned on the screw 47 is rotated in the reverse direction to raise the unit H. The switches 54, 55 are carried by brackets 56, 57 slidably mounted on a vertical bar 58 on which also slide lugs 59, 60 extending from the arm 43 and provided with plungers 61, 62 adapted to engage and close one of the switches 54, 55. The heating properties of the flame from the nozzles may be increased by supplying compressed air through a solenoid-operated valve 63 and pipe 64 to a ring 65 provided with a row of outlets directed towards the combustion zone and supported on adjustable pedestals resting upon the plate 11 of the frame F. The electrical energy for operating the machine is supplied through a cable 69, Fig. 2, connected through a distributor 70 to switches mounted on a panel 71 and to the elements comprising the control means C which effects the operation of the solenoid-operated valves and the motors 16, 50. The panel 71 includes a main switch 72 for starting the machine, switch 73 for stopping it at any time, a gas flow switch 74 for the operation of the valve 23, 24, a switch 75 for operating the solenoid-operated quench valve 33, switch 76 for the operation of the valve 63, switch 77 for operating the motor 16 and switch 78 for the motor 50. Instead of using burners to heat the surfaces, a series of suitablyshaped high frequency inductors may be arranged in juxtaposition to the work so that a series of localised heating currents are caused to flow through the surface to be hardened.