SPRING WASHER TREP®
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SPRING WASHER Secure tightening! TECHNICAL DOCUMENTATION

GRIS DECOUPAGE is the EXCLUSIVE owner and manufacturer of the TREP® brand, an anti-loosening security system for all your mechanical bolted assemblies and all your electrical connection assemblies. The TREP® spring washer consists of 3 or 4 interdependent smooth tapered spring washers assembled with a metal insert. TREP® TAPERED THE MAIN CHARACTERISTICS OF THESE COMPACT, HIGH-ENERGY-CONCENTRATION WASHERS ARE: • Guaranteed resistance to loosening, • Sustained tensioning of assembled elements, • Even distribution of bearing pressure, • High-stiffness, low-deformability elastic system, •...

In assemblies containing bolts of a high property class, resistance to loosening is achieved through the elasticity and taper of the TREP® spring washer. These features promote even distribution of the clamping force and maintenance of constant pressure in the assembled components. At nominal tightening, one of the main characteristics of the TREP® spring washer is to accurately maintain a high level of tension in the bolt by drawing on a substantial reserve of elastic energy stored in a small volume. Its operating principle is simple: clamped between two parts by a nut or bolt head, the...

The elastic properties of TREP® spring washers ensure that the system will withstand loosening in high-stress applications where residual tension in the bolt is of vital importance. After nominal tightening, a mechanical assembly may be subject to a variety of crushing or fatigue stresses. Unscrewing, although less frequent, is also possible, and marring may likewise occur. > In each of these cases, the superiority of our TREP® spring washers has been clearly In an electrical assembly, marking and marring of components are more frequent and problematic the lower the hardness of the mating...

T h e fa t i g u e t e s t s u p p l i e s i m p o r t a n t information as it provides a measure of the durability of the products. Fatigue testing has established that an assembly containing a TREP® spring washer has a better fatigue life than any other system. At the CETIM approved national laboratory we conducted a series of tests on a Vibrophore machine specially designed to determine the fatigue life of an assembly. The bolts in the assembly were instrumented with strain gauges to monitor the tension. LOOSENING: THE PROOF! calculation and experimentation >>> 2nd example of stress:...

The TREP® spring washer also offers high resistance to unscrewing without damaging the surfaces it is fastened to. Unscrewing is in fact a rare phenomenon among the causes of loosening. Unscrewing can be simulated in a destructive Junker vibration test with highly informative results. >>> 3rd example of stress: Unscrewing test > Tests conducted on M08 bolts show that the amount of unscrewing reduces as the number of tapered washers in the assembly increases. UNSCREWING DURING JUNKER TEST (Bolt M08, D=1mm, hardness 1500N/mm2) Proportion of nominal tightening TREP® fastenings with 3 or 4...

What is required in an electrical connection is an element possessing both STIFFNESS and RANGE OF MOVEMENT: two conditions fulfilled by TREP® spring washers. • The TREP® spring washer is sufficiently stiff not to flatten out completely under preload or nominal tightening. • The TREP® spring washer has sufficient range of movement to accommodate any thermal expansion that may occur during the life of the assembly. LOOSENING: THE PROOF! calculation and experimentation To evaluate the variations in tension in a bolt as a result of thermal expansion, the following formula may be applied: >>>...

TREP® spring washers provide a large reservoir of anti-loosening energy whatever the hardness of the material, since they do not need to be anchored in the mating surface to operate efficiently. In contrast to serrated or torque washers, which always mar the bearing surface and render the assembly non-mechanical, the TREP® spring washer is geometrically designed not to cause this phenomenon. Nevertheless, as a precaution when systems are assembled on soft materials, it is advisable to interpose an appropriately sized flat washer. That is why, alongside our TREP® spring washers, we have...

TREP® and TREP INOX® spring washers are manufactured in compliance with RoHS and ELV directives. • TREP® SPRING WASHERS are made from carbon steel C > 0.75%. Their spring characteristics are obtained after core hardening. • TREP INOX® SPRING WASHERS are made from tempering stainless steel X8 CrNiMoAl. Their spring characteristics are obtained after precipitation hardening heat treatment. Whichever version is chosen, our TREP® and TREP INOX® spring washers perform the same duties and achieve the same results in a compact format. Materials & treatments The high-temperature resistance of TREP®...

TECHNICAL CHARACTERISTICS Fields of application of TREP® spring washers YES to TREP®3L spring washers for high bolt property classes ≥ 8.8 MECHANICAL component assembly ELECTRICAL connection assembly • Clamp components in the assembly to one another • Avoid all slipping or separation between components • Control clamping force to ensure there is sufficient contact surface area (avoid overheating and achieve good electrical contact) • Take up play due to thermal expansion and creep of materials YES to TREP®4L spring washers for less high bolt property classes ≤ 8.8 The use of TREP® spring...

Dimensions of TREP® spring washers AVAILABLE FROM STOCK TREP®3L SPRING WASHER Bolt dia. Test load* Stifness 1* electrical connections TREP® 4L SPRING WASHER Bolt dia. Test load* Tension in bolt = load on TREP® in N Load curves of TREP® 3L and tightening fields Load curve test 1 Load curve test 2 Load curve test 3 FOmax Tightening field with bolt class 10.9 FOmin Tightening field with bolt class 8.8 Tightening field for electrical connections * Test load: guarantees that a TREP® spring washer cannot be fully flattened under a load less than the test load. Stiffness: secant stiffness...