Rim-portion stress is defined by cone angle beta after compression, the materila used, and thickness, t. Consequently, during compression the outer rim portions of the disk encounter most of the stresses, which are essentially torsional.
With a 15-degree cone angle, CLOVER/DOME reportedly enhances compression control in nut-and-bolt assemblies, and reduces torque-control requirements for gasket installations.
Forming a clover disk into a dome-shape permits coil spring replacement in space-constrained applications, and provides a lower spring rate with more defection than Belleville washers. Spring function depends on the deflection of three equally spaced disk segments that minimize stress under compression, and are connected by the outer rim portions of the disk.
Outer and inner diameter is dependent on an optimal ratio, OD/ID = 2.6 to 2.8. A lower ratio results in higher stresses and requires decreasing angle beta to remain within allowable stress limits. The width of the rim portion and the geometry of the projecting disk segments can be modified to achieve virtually any spring rate. As the spring is compressed, the ID will be reduced by the cosine of the cone angle beta.
William P. Meade, CLOVER/DOME Products, Franklin Sq., Box 2386, Chapel Hill, NC 27515; Tel: (919) 933-0640; Fax: (919) 933-0800; E-mail: THGMeade@mindspring.com.
For more information, enter 509
Submit your ideas and rough drawings for this section to John Lewis, Designer's Corner, Design News, 275 Washington St., Newton, MA 02458