Background
The department has observed a number of defective ratchet vehicle support stands during inspections at several mining operations.
This type of vehicle support stand is commonly used in workshops for a range of vehicle maintenance support tasks. These devices are very versatile as they are available in a range of sizes and associated mass limits. Ratchet support stands generally require minimal maintenance, have very few parts and are easily height adjustable.
A small but key element of the ratchet vehicle support stand is a lock pin (commonly a roll pin) that rigidly connects the locking pawl to the locking handle. The locking handle provides a downward force on the locking pawl when it engages with the ratchet bar during a height adjustment.
The lock pin can drop out, be damaged through shear forces or become distorted by crushing. If these problems occur the position of the locking handle may give a false impression that the locking pawl is engaged correctly in the ratchet bar.
Summary of hazard
Incorrect handling or use of a ratchet vehicle support stand in a manner not intended by the manufacturer may lead to a damaged lock pin or defective components. This damage may result in the sudden failure of the stand to support a load and could lead to serious or fatal injuries for workers or those in the vicinity.
Contributory factors
The following can contribute to failure of the stand to support the load.
- Faults not being identified through a lack of understanding as to how the locking pawl, lock pin and locking handle work in conjunction with each other.
- Damage or failure of the lock pin through:
- inappropriate handling of the ratchet vehicle support stand
- lifting or dragging the assembly by the locking handle
- adjusting the height of the ratchet bar by manipulating the locking handle using a lever or impact.