Patent GB-529975-A (GB)
Title: Improvements in or relating to apparatus for the hardening of section iron of great length and in particular of rails
IPC: C21D1/63
Filed: 1939-05-10
Abstract: 529,975. Hardening metals. SOC. D'EXPLOITATION DE BREVETS INDUSTRIELS. May 10, 1939, No. 13950. Convention date, May 11, 1938. [Class 72] In an apparatus for hardening metallic sections of great length, especially rails, in which a mechanical device is provided for handling the sections, immersing them in a hardening bath, removing them and releasing them from the handling device, means are provided for controlling automatically the movement of the apparatus so that the sequence of operations of loading the sections, bringing them in contact with the bath, the duration of such contact, and the recording of the same, the unloading of the sections and the return of the handling mechanism to its original position is performed automatically as applied to the hardening of single rails, the rail 5 is secured by a locking device 6 to arms 4 mounted in a shaft which is reciprocated by gearing 11 operated by a sector 10 connected by rod 2 and crank 12 to the driving shaft 9 driven by a motor 1. When the shaft 3 is operated the rail is moved in the direction of the arrow F2 and the head immersed in a hardening bath 7. When the duration of the hardening is regulated as described hereafter and when it is finished the arms 4 are raised to allow lifting hooks to come under this rail, release it from the locking device 6 and move it away in the direction of the arrow F3. The apparatus acts on the motor 1 so as to move the arms 4 according to Fig. 3, in which the rail is displaced from A to B where it remains for a set time, displaced from B to C where the rail is released and the arms returned from C to A. To establish the cycle shown in Fig. 3, cams 20, 21, 22, 23 are connected electrically or mechanically to the shaft 9 and a knob 26 controls the hardening operation by means of relays 25, 26. The duration of the hardening operation is determined by the apparatus 27 which also records such period and a relay 28 controlled by the apparatus 27 moves the rail to the unloading position C. The actuation of a knob 29 causes this return of the apparatus to the loading position A. In starting the motor 1, the relay 43 is used for the normal speed and relay 50 for a reduced speed. When knob 34, is pressed the closing of the relay 25 is controlled by the closing of the safety switch 37 when the rail is locked on its support` and also by a contact 38 operated by a contact thermometer indicating the temperature of the rail. The duration of the hardening operation having been fixed by the apparatus 27, the knob 24 is pressed and if the rail is locked on its support, the contacts 37, 38 are closed and also the contact 40, the relay 26 is energized and is kept energized by the contact 41 of the cam 22. The contact 42 of the relay 26 then closes the curcuit of a coil 43 and starts the motor, the rail being moved into the position B. When the rail arrives in this position the contact 41 is opened as well as the circuit of the relay 26 and the contact 42. Simultaneously the contact 44 closes the circuit and starts the apparatus 27 which times, and records the duration of, the hardening operation. At the end of this time the device 27 energizes the relay 28, opening the contact 43 and starting the motor 1. When the rail arrives at the position C the relay 28 falls and its contact opens, thus stopping the motor. As the rail is released the knob 29 is pressed, energizing the relay 30, the contact 47<SP>1</SP> of the cam 23 being closed. The coil 43 is energized and the arms 4 are returned to the position A and when they have arrived the contact 48 is opened, the relay 30 falls and the contact 47 opens, thus stopping the motor 1. Suitable modifications are introduced into the relay system when three rails are mounted on the arms in sequence and then simultaneously hardened in three baths which are arranged next to each other. The device 27 for timing and recording the duration of the hardening operation is shown in detail in Fig. 9 and comprises a motor 200 which runs at a uniform speed and works two distributer rings 201, 202. The ring 201 has an insulating portion 202 and moves in front of a friction piece 204 ; the ring 202 comprises an insulating portion occupying most of its circumference and a conducting piece 205 and moves in front of a friction piece 206 which is normally fixed but whose angular position can be varied by the chain 207 and hand wheel 208. A recording cylinder 209 is worked by a counting mechanism or a motor 210 which is started up by a contact 211 of a relay 212 also provided with other contacts 213, 214. In front of the cylinder 209 move a series of pointers 216 which are connected to the rings 201, 202 by a chain 217 worked by a wheel 218 integral with the said rings and also a pointer 219 which is operated by the displacement of the part 206 by means of a pinion 220 and the chain device 221 and which shows on the diagram the angular displacement of the piece 206 with reference to the position of the movable rings. Under these conditions the angle a, characterised by the distance L1 is a linear function of the duration of the hardening operation which has been fixed. The pointers 216, 219 are normally removed from the recording diagram but contact is effected therewith only when the arms 4 are in contact with the hardening bath, thus closing the switch 223, causing the energization of the relay 226, Fig. 10, through the contact 224 and operating a striker 227 and thus causing the pointers 216, 219 to contact with the diagram. When the controlling apparatus is operated by hand, these relays are replaced by a bell 290 which warns the operator when the hardening time has elapsed. The apparatus is so regulated that in the position of rest of the rings 201, 202 shown in Fig. 9, one of the pointers 216 is on the abscissa xy. When the rings start rotating, the pointer moves along' a generating line of the cylinder for a period of time corresponding to a complete rotation of the rings. Simultaneously the relay 226 works the striker 227 which causes the pointer 216 to contact with the paper and the recording of the generating line drawn from the abscissa xy is effected along a line corresponding to the effective duration of the hardening operation, represented by the ordinate L 2 . The pointer 216 continues to move until the rings 201, 202 have completed one cycle but the recording on the diagram ceases. When the hardening operation is being carried out, the striker 227 also acts on the pointer 219, which is fixed, and which marks a dot, recording of the duration of that operation. In a modification the rings 201, 202 are replaced by fixed contacts formed by mercury switches which are controlled by cams driven by suitable gearing the movement of which is shown by a pointer moving over a dial. The cams are connected by a differential whose planet wheels are worked by a hand wheel so that one of them can be moved by a hand causing an effect similar to that produced by the piece 206 when three rails are being hardened simultaneously. The temperature of the water in each tank and the rate of discharge of water from one to the other are regulated automatically.