Overloading of Jack Support Blocks
Jack support blocks are designed to provide stability and distribute load safely during vehicle lifting. Using support blocks beyond their rated capacity—overloading—can lead to deformation, failure, and serious safety hazards.
1. Causes of Overloading
Exceeding Rated Capacity: Lifting vehicles heavier than the block’s specified load limit.
Improper Block Selection: Using a block with insufficient size, strength, or material for the intended load.
Uneven Load Distribution: Misaligned placement or angled lifting can concentrate force on a small area, effectively overloading the block.
Multiple Loads: Attempting to lift more than one load simultaneously or stacking support blocks improperly.
2. Effects of Overloading
Block Deformation: Excessive pressure can cause permanent compression, bulging, or cracking of rubber support blocks.
Reduced Stability: Overloaded blocks may tilt, slip, or collapse, compromising vehicle safety during lifting.
Accelerated Wear and Fatigue: Repeated overloading shortens the service life of support blocks and jack components.
Safety Hazards: Overloading significantly increases the risk of accidents, vehicle damage, and operator injury.
3. Preventive Measures
Follow Rated Capacity: Always use support blocks within their manufacturer-specified load limits.
Select Appropriate Blocks: Ensure block size, material, and strength are suitable for the vehicle’s weight and lifting point.
Proper Placement: Align blocks correctly to distribute load evenly and avoid concentrated stress.
Operator Training: Educate personnel on load limits, correct placement, and potential risks of overloading.
Routine Inspection: Check for signs of deformation, cracking, or wear before each use to avoid cumulative damage.
4. Conclusion
Overloading jack support blocks compromises stability, accelerates wear, and poses severe safety risks. Adhering to rated capacities, selecting appropriate blocks, correct placement, and routine inspection are critical to safe and effective lifting operations.
References
Gent, A. N. Engineering with Rubber: How to Design Rubber Components. Hanser Publishers, 2012.
ASTM D2000 – Standard Classification System for Rubber Products in Automotive and Industrial Applications.
Lake, G. J. “Fatigue and Fracture of Elastomers.” Rubber Chemistry and Technology, 2000.
ISO 7619-1 – Rubber, Vulcanized or Thermoplastic — Determination of Indentation Hardness.
ISO 2230 – Rubber Products—Guidelines for Storage and Maintenance.
