Disc springs, also known as Belleville washers, along with die-stamped wave washers, are commonly used in high load engineering applications such as clutches and valves. However there are some major problems involved in their manufacture that makes TFC's Smalley wave springs a preferred choice for some engineers.
Quality: A common problem associated with disc springs and wavy washers occurs because of the differences in mechanical properties as a result of variances in production and heat treatment. All die stamped products are manufactured from annealed material that requires heat treatment after stamping and, because of the inconsistency in characteristics that results from this process, the load at defined working heights can vary enormously. A Smalley wave spring is produced by edge-coiling pre-hardened material to the correct diameter and wave height to produce a product with a guaranteed load at specified work heights.
Installation: Because of the reasons explained above, when installing disc springs, it is difficult to identify the correct number of springs/washers needed to achieve the desired load. In order to correctly understand the quantity needed, the engineer is required to 'trial and error' the assembly with a differing number of springs until the correct load characteristics are obtained. Apart from the obvious problem of time wasting, this also often results in trouble during production caused by the misalignment of the stacked components. In comparison, a single Smalley wave spring eliminates this guess work as it is produced to the exact specifications for the application from a single coil of material and is ready for immediate installation when received by the customer.
No tooling: Since disc springs and wavy washers are a stamped product, they require specific tooling to create the finished article whereas our Smalley products are produced by edge coiling and do not require any tooling. Furthermore, die stamped products are produced from sheet metal and the waste products of this process, particularly where exotic materials such as Inconel and Elgiloy are concerned, is significant. The availability of Smalley products is almost instant since the wire is coiled in-house and is generally available of the shelf and can be produced to customer specific dimensions without compromise to the assembly.
Depending upon the application requirement, we are able to offer a variety of alternatives to disc springs and wavy washers. Smalley Crest-to Crest®, Nested, Interlaced and Wavo® Springs each offer an alternative solution and have been successfully specified in many high load engineering applications.
Having joined the magazine in 2012, Claire developed her knowledge of the industry through the numerous company visits, exhibitions and conferences she attended both in the UK and abroad.
Claire prides herself on keeping readers well informed and up to date with the latest industry news.