Patent GB-752536-A (GB)
Title: Improvements in tunnel kiln loading and discharging mechanism
IPC: F27B9/02
Filed: 1954-10-15
Abstract: 752,536. Control of several motors; actuation of switches. NORTON GRINDING WHEEL CO., Ltd. Oct. 15, 1954 [Oct. 28, 1953], No. 29770/54. Classes 38(3) and 38(5). [Also in Groups XII and XXX] Mechanism for charging and discharging tunnel furnaces, particularly furnaces of the type disclosed in Specification 673,532 [Group XII], comprises batt feed conveyer chains 40, 41, carrier chains 60, 61, pusher chains 80, 81 each provided with a pusher dog 90, returned conveyer chains 100, 101 conveying the batts 24 from the rear end to the front end of the tunnel, and transfer arms 126, 161 at the front and rear ends respectively, feeding the batts from and to the return conveyer chains 100, 101. The feed chains 40, 41 and carrier chains 60, 61 move the batts 24 toward the tunnel entrance, and the dog 90 pushes the first batt into the tunnel for a distance of one batt, discharging another at the other end at the same time. The feed chains 40, 41 are driven by chain and sprocket gearing from a motor 54, the carrier chains 60, 61 and the pusher chains 80, 81 by a reversible motor 69. The drive to the carrier chains 60, 61 incorporates an over-running clutch (Fig. 10, not shown), so that when the motor 69 is reversed the pusher chains 80, 81 are also reversed, but the carrier chains 60, 61 remain stationary. The transfer arms 161 at the rear end of the tunnel are rocked through 180 degrees by a motor 186 and L-shaped brackets pivoted to each of the arms 161 lift a loaded batt which has been pushed out of the furnace, and transfer it to the return conveyer chains 100, 101 which are driven by chain and sprocket gearing from a motor 115. The transfer arms 126 at the front end of the tunnel are similarly operated by a motor 150 to lift the batt into a starting position on the feed conveyer chains 40, 41, where it is unloaded. The cycle of operations is controlled automatically by an electric timer 197 and by switches operated by various moving parts of the mechanism, and forming part of the circuit shown in Fig. 12. After a predetermined interval when the timer is started, contacts 198 close a circuit through switch LS7 to energize relay CR2, starting the motor 150 to swing the transfer arms through 180 degrees, transferring the lower batt to the upper starting position, and depositing the upper batt on the feed chains 40, 41. This actuates switch LS1 to energize relay CR6, starting the feed chain motor 54 and holding switch LS2A closed. The batts are fed forwardly, and the first closes switch LS2 energizing relay CR7 to start the reversible motor 69 driving the carrier chains 60, 61 and the pusher chains 80, 81, and holding switch LS4 closed. As a batt moves off feed chains 40, 41 on to carrier chains 60, 61 it opens switch LS2 breaking the holding circuit for relay CR6 and stopping motor 54. The dogs 90 push the batt against those already in the tunnel, moving them along and opening switch LS4 to de-energize relay CR7, reversing the motor 69. Carrier chains 40, 41 stop, and pusher chains 80, 81 are reversed until the dogs 90 open switch LS3 to stop motor 69. As a batt emerges from the tunnel, it closes switch LS5, energizing relay CR5 to start motor 185, thus operating the transfer arms 161. A lug 189 on the transfer arm gear 188 releases switch LS6 to hold relay CR5 and energize relays CR4 and CR3. After the gear 188 has rotated through 180 degrees, a lug 190. moves switch LS6 into its former position to de-energize relays CR4 and CR5, stopping motor 185, and starting the return conveyer motor 115. The first batt on the return conveyer 100, 101 actuates switch LS8, breaking the holding circuit for relay CR3 to stop motor 115, and energizing the timer 197 to start the next cycle.