ES344341A1 - Improvements in or relating to industrial lift trucks - Google Patents

Abstract

The mast of a lift truck 10 is formed of four nested sections 12, 13, 14, 15, the first section 12 being mounted on the truck and the fourth section 15 mounting a lifting carriage 16 for vertical movement therealong. The mast is extended by a combination of a two stage ram 17 disposed between the third and fourth sections 14, 15, and three ropes 18, 19, 20. The first of which 18 is connected between the upper ends of the first and third sections 12, 14, and passes under a pulley 21 at the lower end of the second section 13, the second of which 19 is connected between the upper end of the second section 13 and the fourth section and passes under a pulley 22 at the lower end of the third section and the rope 20 is attached to the fourth section 15, passes over a pulley 23 mounted on the ram 17 and has its other end attached to the lifting carriage 16. In operation the first stage of the ram raises the carriage 16 to its uppermost position on the fourth section and the second stage raises the fourth section which simultaneously through the ropes 18, 19 raises the second and third sections. In alternative embodiments (not shown) the ram 17 is disposed between the second and third section or between the first and second section respectively and the passage of the ropes is suitably modified. The mast may be moved horizontally with respect to the track along guideways 42 by a ram 40.