GB1057140A - Industrial lift truck - Google Patents

Abstract

1,057,140. Masted lift trucks. EATON YALE & TOWNE Inc. Dec. 5, 1963 [Jan. 9, 1963; Feb. 27, 1963], No. 48050/63. Heading B8H. In a lift truck, a load carriage 14 is raised on the mast, which comprises fixed primary uprights 11 and slidable secondary and tertiary uprights 12, 13, and the mast is extended by an hydraulic ram 15 having a cylinder 17, which is movable vertically relative to the mast, and a telescopic piston 18, 19. Chains 16 extend from anchorages on the carriage 14, and pass around sheaves 20, 21, supported on brackets 26, 24 mounted at the top of the piston 19 and adjacent the lower end of the cylinder 17 respectively to brackets 22 adjacent the tops of the uprights 11. The brackets 24, 26 are provided with guides 25, 27 which slidably engage guide rails on the uprights 12, 13 respectively. In operation, initial extension of the ram 15 raises the carriage 14 at twice the speed of extension of the ram until the guides 27 engage stops 28 adjacent the top of the tertiary uprights 13, Fig. 9 (not shown), whereupon the uprights 13 are raised at the speed of extension of the ram and the carriage 14 continues to rise at twice the speed of extension of the ram until it engages stops 29 secured to the tops of the uprights 13. As the uprights 13 are initially raised, a latch member 30 thereon automatically engages the bracket 26 to lock the piston 19 to the uprights 13. After the carriage 14 has reached the top of the uprights 13, further extension of the ram raises the carriage 14 and uprights 13 as a unit and raises the ram through the chains 16 and sheaves 21. Upward movement of the ram raises the secondary uprights 12 through engagement of the guides 25 on the ram with stops 31 at the lower end of the uprights 12. The uprights 13 now rise at the speed of extension of the ram plus the speed of upward movement of the ram cylinder, while the uprights 12 rise at the speed of upward movement of the ram cylinder. Further extension of the ram causes the uprights 13 to pick up the uprights 12 through engagement of stops 32 adjacent the lower end of the uprights 13 with stops 33 at the upper end of the uprights 12. In a modification (not shown), the stops 31 on the uprights 12 are omitted so that the uprights 12 remain stationary until they are picked up by the uprights 13. The latch member 30 is held in the non-latching position, when the uprights 13. are fully lowered, by engagement with the top of uprights 11 and is spring-urged into latching engagement with the bracket 26 on the ram piston 9 when the uprights 13 are raised.