At Vulcan Spring, we’ve encountered countless instances where spring prototypes are not utilized correctly in applications. These misused prototypes might function temporarily but fall short in long-term performance. Below, we highlight common spring misuses and provide expert solutions from our seasoned custom spring engineering team.
Utilizing a Conforce® Spring within a case-driven Torque application
Issue:
A Conforce® Spring (Constant Force Spring) is placed in a case, and the outer end is secured to the outside end of the case. The inner end of the spring is then slotted into the arbor by manipulating the inner most coil. The case then rotates, winding the coils of the spring which generates torque.
Expert Recommendation:
In this scenario, a Conforce® Spring is mistakenly used as a Power Spring, which is meant for linear motion, not rotational. Our engineers can design a proper Power or Conpower® Spring to optimize torque and turns. This solution simplifies final assembly, provides more available turns, increases life cycles, and expands torque options.
Back-Bending a Conforce® Spring
Issue:
A Conforce® Spring is wound opposite to the coil set onto a spool to create torque.
Expert Recommendation:
Subtle differences exist between a Conforce® Spring and a Contorque® Spring (Constant Torque Spring). Back bending a Conforce® Spring can cause it to “take a set,” expanding the original coil diameter, reducing torque and potentially causing permanent damage to the spring. A Contorque® Spring, designed for opposite winding onto a recommended spool diameter, is a better choice. It allows for ease of installation onto the corresponding spools and for a proper torque output.
Extending a Power Spring from its Case
Issue:
A Power or Conpower® Spring is wound into a case. The outer end is extended out of the case and expected to retract, similar to a tape measure. However, this spring, designed for rotational torque, is improperly used for linear force.
Expert Recommendation:
To achieve the required linear action, a Conforce® Spring can be designed to meet extension, force, and life cycle requirements. Alternatively, using the torque of a Conpower® Spring with an attached cable can allow for linear deviation of an object attached to the cable. Another option is a Contorque® Spring assembly, which can accomplish the same thing through the use of an input and output spool.
Attaching the Inner End of a Conforce® Spring to a Spool
Issue:
A Conforce® Spring is modified to attach the inner end to a spool, often to utilize the rotation to drive a mechanism or act as a stop for spring extension.
Expert Recommendation:
A Conforce® Spring should not be attached to a spool by deforming the inner end, and the spool should never be used as a stop. Instead, the spring should be designed to have at least 1-1/2 wraps of material on the spool when fully extended. For torque requirements from a spool, consider a Contorque® Spring design.
Using a Constant Torque Spring for Extension Due to the Long Spring Length
Issue:
A stock Contorque® Spring is used for a linear application to leverage its long length.
Expert Recommendation:
While a Contorque® Spring can provide linear force, it is neither calculated nor controlled for this purpose. A general rule is that the extended length of a spring should not exceed 50 times its inside diameter. Exceeding this can cause the spring to twist along its extended length. A better solution involves using a cable assembly mounted to a Contorque® Spring.
When in Doubt, Consult the Custom Spring Design Experts
Spring design can be complex, and mistakes happen. That’s why our Vulcan Engineers are here to help. With extensive experience and expertise, they can select or custom design the perfect spring for your application.
Contact Vulcan Spring today to create a custom spring tailored to your design needs, explore our collection of premade springs, or partner with us to ensure your designs perform flawlessly.