Articulated Leg Foot Pad
An articulated foot pad is the base part connected to the leg shaft by a ball joint that can angle itself to suit the ground. On sloping or uneven ground it lets the base make full-surface contact. The load is thus spread over the whole plate area and the point pressure caused by edge contact is eliminated.
A fixed base touches on only one of its edges if the ground is sloping. The pressure at that edge rises to a multiple of the design value, and both sinking into the ground and the leg's tendency to slip increase. The ball joint lets the base conform to the ground angle and thereby distributes the load over the whole area.
- Slip resistance: full contact also increases the friction force between the base and the ground.
- Mechanism protection: the joint reduces the lateral component being imposed on the threaded shaft as a bending moment.
- Maintenance: sand and rust getting into the joint clearance lock the movement; clean and grease it.
Pad size varies by manufacturer and leg class; there is no single standard size across the industry. The governing principle is to enlarge the contact area and to make sure the contact is full over the whole surface. On sloping ground, using an additional base plate together with an articulated pad combines the benefits of both.
The context in which this term is used: How to choose levelling leg capacity