GB1275342A - Mast assemblies for lift trucks - Google Patents

Abstract

1275342 Masted lift trucks CLARK EQUIPMENT CO 26 March 1970 [23 April 1969] 14786/70 Heading B8H A mast assembly 34 for a lift truck comprises a stationary outer mast section 38 and intermediate 40 and inner 42 mast sections movable by a ram 54, guide rollers (98) (100) (104) (106), Fig. 4 (not shown), mounted within the mast sections and a load carriage 86 mounted on the mast section 42 such that the load carriage may be elevated to a full free-lift position prior to elevation of mast sections 40, 42 and in addition, the guide rollers may be serviced without requiring complete disassembly of the mast assembly 34. The mast sections 38, 40, 42 are formed in channel shape (44) (62) (74),Fig.4(notshown), and each is connected at its rear by the bars. The multiple cylinder ram 54 comprises five hollow cylindrical members, Fig. 14 (not shown), the outer of which (144) is connected to an anchor plate 160 to which chains 166 are anchored, said chains being reeved over sprockets 158 on a crosshead 154 mounted on the ram 154 and connected to the load carriage 86. To effect the initial free lift of the carriage 86 fluid pressure is applied to the ram 54 thereby raising the sprockets 158. Further chains 168 are connected to the plate 160 and extend about sprockets 170 on the lower tie bar 68 of mast section 40 and are anchored to brackets 172 secured to the channel members 44 of the outer mast 38. After free-lift of the carriage 86 has taken place, elevation of the intermediate mast section 40 out of mast section 38 is caused by the elevation of the anchor plate 160 and chains 168 on application of further fluid to ram 54 and the inner mast section 42 is simultaneously telescoped out of mast section 40, thus providing maximum extension of the mast assembly 34. By mounting a ramp (180) under the drive wheels 24, Fig. 5 (not shown), the guide rollers may be serviced by lowering either the inner mast section 42 or the intermediate mast section 40 to positions beneath the wheels 24. This is achieved by removing a stop member 70 on the intermediate mast section 40 which abuts the upper tie bar of the outer mast section 38, actuating the ram 54 to effect free lift of the carriage 86 and then raising the inner mast section 42, maintaining it raised by means of a lifting bracket 134 and then lowering the intermediate mast section 40 by means of ram 54 to expose the rollers (100), Fig. 9 (not shown), while in a similar manner the rollers (106) may be exposed by lowering the inner mast section 42 on removal of a member 82 from its lower tie bar, the intermediate mast section being held raised by a chain (188), Fig. 10 (not shown).