Products: John Evans' Sons

John Evans' Sons, is the international leader in design and manufacturing of constant force springs, constant force spring assemblies and pusher springs (variable force). If your application is to counterbalance or to obtain a large amount of torque through a small amount of rotation, our custom spiral torsion springs are well suited. Custom design, in-house tooling and precision manufacturing, combined with a wide and varied stock spring selection allows us to serve a wide variety of applications from fenestration & military to medical, high-tech and aerospace. We provide impeccable service from start to finish and set the standard for world-class precision spring products.

Industries served:

Window Manufacturing – Custom constant force window balance springs (including the SideLoad® & the Drop-In constant force balance systems)

di Series (Drop In) – the most technologically advanced Drop-In Balance System for Hung Windows in the Industry.


  • Low cost and a deduction of on hand inventory
  • and SKU's.
  • Quiet operation with low operating forces
  • Superior cam strength and reliability
  • Higher weight AAMA qualified springs

SideLoad™ Constant Force Balance System
...a better option for side load windows.

Our SideLoad™ Constant Force Balance System uses AAMA qualified springs and is a simple conversion from block & tackle. Compared to block & tackle, the SideLoad™ Constant Force Balance System offers:

  • A lower price
  • Significantly reducing operating forces
  • A substantial reduction of on-hand inventory
  • Reduction of "special order" balances & freight costs for these
  • A tighter fitting sash


Drop In System

Side Load System

John Evans' Sons
John Evans' Sons Springs for Doors and Windows

Fenestration Components Inc. proudly represents John Evans' Sons throughout Western Canada.