Swelling and Deformation of Jack Shock-Absorbing Rubber Blocks: Causes and Preventive Measures
Jack shock-absorbing rubber blocks are critical for cushioning, vibration reduction, and load distribution during lifting operations. Swelling and deformation are common issues that compromise their performance and safety. Understanding the underlying causes and implementing preventive measures is essential for reliable jack operation.
1. Chemical Exposure
Swelling is often caused by contact with oils, fuels, solvents, or other chemicals that are incompatible with the rubber material. These substances penetrate the rubber matrix, causing it to absorb the liquid and expand. Over time, this leads to permanent deformation, loss of elasticity, and reduced shock absorption capability.
2. Inappropriate Material Selection
Using a rubber compound that lacks resistance to the specific environmental chemicals or operating fluids can accelerate swelling. For example, natural rubber may swell when exposed to oils, while nitrile butadiene rubber (NBR) offers better oil resistance. Polyurethane and EPDM each have specific resistances and limitations that must match the working environment.
3. Elevated Temperature and Aging Effects
High temperatures can soften the rubber, increase its permeability, and accelerate chemical absorption. Thermal aging combined with chemical exposure further reduces mechanical strength, increases susceptibility to creep, and promotes bulging and deformation.
4. Mechanical Stress and Overloading
Excessive compressive or impact loads can exacerbate swelling-induced deformation. The combined effect of internal chemical absorption and external mechanical stress causes lateral expansion and permanent shape changes, reducing the block’s load-bearing stability.
5. Preventive Measures
Material Selection: Choose rubber compounds specifically designed for chemical resistance relevant to the jack’s operating environment. NBR is recommended for oil exposure, EPDM for outdoor and weather resistance, and polyurethane for high-load durability.
Environmental Control: Minimize exposure to incompatible chemicals and high-temperature conditions.
Load Management: Avoid overloading and high-impact operations to reduce stress on swollen areas.
Regular Inspection: Periodically check for early signs of swelling, softening, or deformation, and replace affected blocks promptly.
Protective Coatings: Applying compatible rubber coatings or sealants can provide a barrier against chemical penetration and slow swelling.
Conclusion
Swelling and deformation of jack shock-absorbing rubber blocks are primarily caused by chemical exposure, improper material selection, elevated temperatures, and excessive mechanical stress. Through proper material choice, controlled operating conditions, and routine inspection, the service life and performance reliability of rubber buffer blocks can be significantly improved.
References
Gent, A. N. Engineering with Rubber: How to Design Rubber Components. Hanser Publishers, 2012.
Lake, G. J. “Fatigue and Fracture of Elastomers.” Rubber Chemistry and Technology, 2000.
ASTM D471 – Standard Test Method for Rubber Property—Effect of Liquids.
ISO 23936-1 – Petroleum, Petrochemical and Natural Gas Industries — Materials Resistant to Swelling in Hydrocarbon Environments.
