Patent GB-1095716-A (GB)
Title: Tow line conveyor systems
IPC: E01B25/28
Filed: 1965-08-09
Abstract: 1,095,716. Tow line conveyer systems. S. I. HANDLING SYSTEMS Inc. Aug. 9, 1965 [Aug. 10, 1964], No. 34026/65. Heading B7L. A tow line conveyer system comprises a floor 20 having a drag line or wheeled link conveyer means engageable by the tow pin 16 of a tow truck (not shown) and extending below a main truck slot 12 in the floor 20, the main slot 12 being intersected by shunt slots on either side, e.g. the shunt slot 14 which has a switch plate 22 displaceable via actuator means by a treadle member actuated by a selector pin 18 on a tow truck travelling along the main slot, to move the plate 22 from an inoperative position in which it does not obstruct the main slot to an operative position in which it presents an abutment surface in the main slot to guide the tow pin 16 of the truck travelling along the main slot into the shunt slot 14. In an embodiment, Figs. 1-4 (only Figs. 1 and 3, shown), the selector pin 18, which may be mounted at different distances laterally of the main slot, is engageable with a treadle 26, pivoted at 28 between plates 30 so as to extend upwards through a slot 24 in a floor plate 21, and connected by actuator means comprising a rod 46 to a spring-loaded catch crank 48. A switch arm 62, mounted on a shaft 70 is normally prevented by the catch crank 48 from rotating anticlockwise due to the bias of the spring 68 so as to rotate the switch plate 22 mounted on the shaft 70 into the main slot 12. When a selector pin 18 engages the treadle 26, the plate 22 is thus swung into its operative position. The plates 30 are mounted on a platform 32 secured to a shaft 34 journalled in brackets 36 depending from the plate 21, so that if the plates 30 are accidentally depressed against the action of a spring 42 acting on an arm 38 of the shaft 34, the treadle and plates are self-returning. A spring-loaded bolt 44 provides adjustment of the upward extension of the treadle above the plate 21. A reset arm 76 is fixed on the shaft 70 and is engaged by a truck which has been switched into the shunt slot 14, to move the switch plate 22 into its inoperative position. Overload protection means for the shunt slot 14 comprise a bar 82 engageable by the pin 16 of the end truck in the slot 14 when fully occupied, the bar 82 being mounted on parallel links 84, 85 so as to tension a spring 66 attached to the switch arm 62 against the bias of the spring 68 to prevent the switch plate 22 being rotated. In another embodiment, Figs. 5-9 (not shown), a mechanism is provided for rectifying accidental rotation of the switch plate 22 to an operative position. The mechanism comprises a pivoted lever (86) projecting into the main slot and movable in anticlockwise direction to rotate the accidentally released switch arm 62 in a clockwise direction to be retained in an inoperative position by the catch crank 48. The lever (86) is movable either by a special link or dog (98) of the drag line or conveyer means (Figs. 6, 7), or by the tow pin 16 when the lever (86<SP>11</SP>) is in the same plane as the floor 20 (Fig. 8), or by the wheels (101) on the conveyer means or drag line chain when the lever (86<SP>1</SP>) extends into the path of the wheels. The selector pin 18 may subsequently move the switch plate 22 to operative position. The arm 76 may be replaced by a latch releasable by a mechanism along the shunt slot engageable with a tow truck. The floor 20 slopes downwards along the shunt slot 14 away from the main slot 12 as no conveyer means is provided for the shunt slot. In a further embodiment, Figs. 10-12, 14 (not shown), the catch crank (48a) normally prevents the arm (62a) from rotating clockwise so as to close the shunt slot 14. Overload protection means (80a) for the shunt slot 14 is connected to the catch crank (48a) by means of a cable (116) extending around pulleys (112), (114), so that when the slot 14 is overloaded, the catch crank (48a) is held clear of the arm (62a) and the switch plate (22a) is thus never reset by the plate (76) extending into the main slot 12. In normal use, a selector pin (18a) on a truck engages the treadle (26a) to release the arm (62a) so that the shunt slot (14a) is closed. In Fig. 13 (not shown), the cable (116<SP>1</SP>) extends around a pulley (114<SP>1</SP>) for connection to the platform (32a) so when the slot (14a) is overloaded, the treadle 26 and plates 30 are retracted through the slot 24.