GB1424651A - Support leg for mobile cranes - Google Patents

Abstract

1424651 Vehicle supports HIAB-FOCO AB 29 Jan 1974 [8 Feb 1973] 04026/74 Heading B7J A leg support for mobile cranes comprises an outer leg section 4 and an inner leg section 5 telelescopically displaceable by an hydraulic piston and cylinder unit 7, 8, the leg section 5 having a foot piece 6, the section 4 in use being swingable in a vertical plane outwardly of a crane, together with the unit 7, 8 about a horizontal pivot shaft 3 mountable or the crane body 1 via a bracket 2, the swinging movement being caused by reaction when an abutment 22 on the section 5 co-operates with an abutment 28 on the bracket 2, the support leg 4, 5 being lockable in a vertical position or in the oblique outward position. The invention is characterized in that the support leg 4, 5 is also connected to the bracket 2 by two stay portions 10, 11 interconnected by a knee joint 9, the portion 11 being hinged to the leg section 4 by a bolt 13 whilst the stay portion 10 is hinged to the bracket 2 by a bolt 12. The leg section 4 is slotted at its upper end to receive a catch bar 15 vertical slidable in the bracket 2 against the action of a spring 26. Pivoted to the catch bar by a bolt 16<SP>1</SP> is a follower means 16 under the urge of a spring 17, the end surface 18 of the follower 16 being engageable with a boss 20 on stay portion 10. The leg section 4 is provided with a locking loop 25 and is urged towards the bracket 2 by a spring 27. The loop 25 is engageable with a locking boss 24 on the catch bar 15 as a bevel 23 of the catch bar 15 passes over the loop 25 when the support leg is moved to the vertical position. When the leg 4, 5, is in its vertical parked position, Fig. 2, the section 5 if desired can be lowered to engage the ground 29. To swing the leg 4, 5 outwardly, however, the section 5 is pulled inwardly of the section 4 by the unit 7, 8 so that the abutment 22 engages a fiange 21 on the catch bar 15 to lift the latter and move the locking boss 24 out of the loop 25 and disengage the support leg from the bracket 2. Further upward movement of the section 5 causes the fiange 21 to abut the abutment 28 of the bracket 2 whereafter the leg is swung outwardly due to reaction force to the position shown in Fig. 1, the knee 9 then passing downwardly over a line 14 joining the pivot bolts 12, 13 and the follower 16 abutting the boss 20 since the catch bar is urged downwards by the spring 26. The section 5 is then extended by the unit 7, 8. The leg 4, 5 is returned under the urge of the spring 27 to the vertical position by retracting the section 5 so that the abutment 22 contacts the flange 21 and lifts the catch bar and rotates, via the follower 16 and boss 20 on the stay portion 10.