When evaluating your medical equipment design, John Evans’ Sons offers several counterbalance options to assist and/or enhance articulated instruments.

Whether your design requires a counterbalance utilising…

  • constant force springs
  • constant force spring motors
  • spiral torsion springs
  • spring reels

… the capabilities have significant benefits compared with traditional helical springs and gas springs.

Constant force springs provide a smooth range of motion and a constant load in either extending or retracting direction. This spring design has no inertia to overcome when considering the initial position starting forces. Constant force springs are compact and mount easily to existing hardware. Applications include counterbalancing of computer monitors in fixed and mobile applications, dental X-ray equipment articulated arms, as well as medical equipment drawer closing mechanisms.

Constant force springs, constant force spring motors and spiral torsion springs provide rotational energy to move or turn components in medical devices. Springs can eliminate costly and complicated motors decreasing your device size and cost.

Spiral torsion springs allow for rotation in two directions and a "return to centre" capability. Used in pairs at right angle to each other, a wide range of motion can be achieved in two axis configuration, while still preserving the "return to centre" feature. An example application of this is a dental X-ray head unit.

Spiral torsion springs are normally used in applications requiring less than 360° degrees of rotation. They are generally used to obtain a large amount of torque through a small amount of rotation.

Spring powered reels (arbor mount or base mount) are available with a large range of forces, cable lengths and travel. Spring powered reels mount easily, and with pre-installed cables, attach quickly.

Spring sub-assemblies may call for the use of components made of a variety of materials (moulded plastic, machined metal, rubber). We frequently are able not only to produce the specialty spring, but then to assemble the spring and various customer-designated or customer-supplied additional parts into a completed sub-assembly.

Often, it is cost-effective to consider sub-assembly at the point of spring manufacture, and in this approach, John Evans excels.

John Evans has a fully staffed engineering department that is eager to discuss the design requirements and equipment counterbalancing challenges in your design and prototype phase. In fact, many choices of counterbalances springs/reels are stock items and can ship quickly to aid in your product evaluation.