2.0 MOUNTING
Drum design and bearing selection can be important factors in NEG'ATOR mounting. The springs hold by a natural gripping action as long as a turn or more of material remains on the drum at maximum extension. In some cases, such as long extensions where misalignment is possible, a provision for guidance is suggested. The material can be guided by fastening the inner end to the drum in a manner that does not deform the strip. Where the material could be drawn off the side of the drum, flanges can be used as guides. There is no friction inherent in the NEG'ATOR constant-force spring. However, friction and resulting hysteresis are influenced by the bearing surface selected for the spring and drum assembly.

CAVITY MOUNTING 
NEG'ATOR springs may be mounted without a bushing in a cavity (Figure 5a). This mounting is simple and inexpensive, however, friction encountered can result in relatively high hysteresis. Another variation, the "rolling action unit" (Figure 5b) has its free end fixed allowing the coil to push against a movable member.



MULTIPLE MOUNTING 
Multiple mounting can be used to increase force. Constant-force springs mounted back-to-back make the sum of their forces available at one point. This method also provides stable extension over long deflections. (Figure 6)
Tandem mounting makes the sum of two spring forces available at a single point but does not add stability. (Figure 7) Pulley mounting doubles the force of a single constant-force spring but reduces the cycle life. (Figure 8)
Laminar mounting, interwinding of two or more springs as an assembly, offers the sum of their forces in a minimum of space. (Figure 9)