Examples of Tokai Spring achievements

Tokai Spring Industries possesses unique manufacturing technology based on many years of experience of delivering products to customers in the steel manufacturing industry. Even if equipment cannot be easily replaced, such as steel manufacturing equipment, new functions can be added to existing equipment by designing springs that fit into the limited space. Our springs play an active role in such improvement applications.

Problems and challenges

“We need to install a new device to hold down flat steel, and we want to use springs in that device!” That was the request we received from a steel manufacturer. Springs are used to fix the flowing steel at several points. A large stroke is required because the height difference when there is no steel and when several sheets are stacked is large. It was difficult to design a spring with a large load and stroke for the limited installation space.

Solution

In response to the customer’s request, we decided to propose a “bow-shaped plate spring”. The stroke was ensured by combining two stages in series with different orientations. The optimum plate thickness was calculated and three plates were stacked in a row to secure the load and stress. In other words, the complete spring was a combination of three stacked plate springs arranged alternately in two stages. However, there was still one problem: since the two stages were arranged in series, the springs would shift during use and the combination would collapse. We dealt with this by bolting the non-stressed parts at both ends to prevent displacement.

Results

When we manufactured the spring and tested the load, the load was different from the calculated value and was stronger than the required specification. The cause was that both ends were fixed with bolts, which resulted in a strong load. Three parallel plates were too strong, so we reduced the number of parallel plates and tested again. As a result, by reducing the number of stacked plates, we were able to successfully meet the required specifications for both load and stroke. We immediately informed the customer of this fact, and after receiving the approval, we were able to deliver the product.
These plate springs are still in use today, and our customer is satisfied with them.