Patent GB-771801-A (GB)
Title: Roll and platen mill
IPC: B21B31/04
Filed: 1954-10-25
Abstract: 771,801. Rolling. SMITH CORPORATION, A. O. Oct. 25, 1954 [Oct. 26, 1953], No. 30706/54. Class 83 (4). [Also in Group XXVI] In a roll and platen mill a fluid pressure clutch is automatically operated for a given period of time according to the number of passes required, and the roll is automatically raised and lowered in sequence with the reciprocations. The roll is automatically reset for successively reduced passes by a toggle mechanism 57, Fig. 1, which is closed by cam 71 in the machine drive, one end of the toggle mechanism being mounted on another eccentric 59 which is automatically pre-set for the required pass. An overload device further automatically releases the toggle mechanism at predetermined pressures. The heated blank 35 to be successively drawn under an adjustable roll 11 is carried on a platen 33 slidable along tracks 32 on the machine bed 31. The platen 33 is reciprocated from a drive shaft 45 by an eccentric 44 acting through a follower 41, lever 38 and connecting rod 37. The stroke of the platen may be varied by attaching the follower 41 to the lever 38 by alternative pins 42, 43. The drive for the shaft 45 is obtained from a motor 78 through a train of gears 76, 74, a flywheel 80, pneumatic clutch and a pneumatic brake being incorporated. The roll 11 is mounted in a frame 8 comprising crossheads 6, 9 connected by tie-bars 7 and vertically slidable between brackets 65 on the bed 31. The frame is yieldingly supported by a counterbalancing air cylinder 5 and is adjustably held in the vertical position to set the pass by the toggle mechanism 57, which comprises a cranked arm 58 and link 62 connected by a pivot-pin 63. A push-rod 66 actuated from the cam 71 on the drive-shaft 45 through a follower 68 oscillating about a pivot 69 opens and closes the toggle mechanism on each revolution of the shaft 45 to bring the roll 11 into position for the next pass. In the event of the roll pressure being too high a crank arm 87 between the follower 68 and the push-rod 66 is automatically rotated against a pre-set pressure in a pneumatic cylinder 85 and releases the toggle 57. Adjustment of the release pressure may be obtained by varying the pressure in the cylinder 85 or by adjusting the length of the push-rod 66 by means of a turnbuckle 93 to change the angular setting of the toggle. The roll 11 is set for each successive pass by automatic pre-set rotation of the eccentric 59 by which the upper link 58 of the toggle is pivoted to the machine bed 31. The eccentric is rotated by a rack-and-pinion 94, 95, Fig. 8, the rack being moved by one of a pair of racks 99, 100 actuated by pneumatic cylinders 111, 112 and engaging a pinion 98 on the end of the rack 95. For three pass operation the cam 59 is set to position for the second pass by automatic actuation of the cylinder 111 and rack 99 until an adjustable stop sleeve 103 set by a hand-wheel 133 engages a fixed stop 107. Further rotation is obtained for setting the roll for the third pass by actuation of the cylinder 112 and rack 100 until a similar adjustable sleeve 106 engages a fixed stop 108. Solenoid valves 113, 114 controlling the cylinders 111, 112 are automatically actuated through a series of switches 192, Fig. 16, which are pre-set to be closed as required by shifting a push-rod 174 which moves dogs 189 into different positions according to the number of passes required. The dogs are engaged by cams 155 rotating at different speeds and arranged to close the switches 192 in the sequence required. A cam 175 on the push-rod 174 further operates to close one of three switches 170 which determines which of a further bank of three switches 160 actuated by cams 156 shall be effective to open the circuit controlling a solenoid valve 164 operating the clutch and brake mechanism to stop the machine after one, two or three revolutions. The push-rod 174 is operated through a connecting-rod 181, Fig. 8, actuated from a lever 182 pivoted on the machine bed. In operation the roll 11 is set in the required positions by shims, the setting being shown by a rack indicator 136 driven through a pinion 135 from the eccentric 59. The final pass may be set by engagement of the roll 11 with side-plates 36 on the platen 33. The drive for the roll 11 may be effected by frictional engagement with the work or a gear 47 engaging a rack 46 on the underside of the platen 33 may drive the roll through gears 52, 53, 54 arranged on links 55, 56 which permit pass adjustment. The bearings for the roll may have coolant passages and the roll 11 and platen 33 may be preheated by gas flmes from burner pipes 197, 198 (Fig. 3, not shown).