window springs

Constant Force Window Balance Springs

As the world leader in constant force spring technology,
John Evans’ Sons (est. 1850) has produced well over 100 million
high performance window balance products.

The following innovations are the result of John Evans’ Sons unparalleled experience and technical expertise.

Patent Information by product series HERE.

Di FLEX 500 BALANCE SERIES

…The most flexible constant force balance system for 1/2” sash windows.

Offers the following:

  • Ability to transition from a fixed coil balance to an inverted coil balance by simply changing the mounting orientation and attaching a mounting clip to the coil spring.

 

  • Reduced SKU’s, springs are pre-assembled in holders (singles and doubles), quickly make triple and quad assemblies by connecting the spring assemblies together.

Di FLEX 500 Balance System

1/2" Series Drop-In Balance System Intro.

Di FLEX 500 Balance System

1/2" Series Drop-In Balance Components

Di FLEX 500 Balance System

1/2" Series Drop-In Balance 4 Step Assy. Procedure

Di FLEX 500 Balance System

1/2" Series Drop-In Balance Fabrication Instructions

Di FLEX 500 Balance System

1/2" Series Drop-In Balance Clip-less Assy. Steps

1/2" Drop-In Series

1/2" Series Spring Selection Guide

Di FLEX 500 Balance System

1/2" Series Drop-In Balance Fixed Config. Weight Chart

Di Flex 500 fixed assy. demo

Di FLEX 500 Balance System

1/2" Series Drop-In Balance Inverted Config. Weight Chart

Di Flex 500 inverted assy. demo

Di SERIES for 3/4" SASH WIDTHS

…the most technologically advanced Drop-In balance system for hung windows.

Offers the following:

            • low cost and a reduction of on-hand inventory
            • quiet operation with low operating forces
            • superior cam strength & reliability
            • higher weight AAMA qualified springs
            • Patents: see link above

Di-750 Balance System

3/4" Series Drop-In Balance System Intro.

Di-750 Balance System

3/4" Series Components & Configurations

Di-750 Balance System

3/4" Series 4 Step Assy. Procedure

Di-750 Balance System

3/4" Series Fabrication Instructions

Di-750 Balance System

3/4" Series Spring Load Chart

3/4" Drop-In Series

3/4" Series Spring Selection Guide

SFI (Static Friction Inverted) Constant Force Balance System

…a better option for one inch pocket windows.

 

Our SFI Constant Force Balance System uses AAMA qualified springs and is a simple conversion from block & tackle.

The SFI Constant Force Balance System:

                  • Designed for a one inch pocket
                  • As few as three SKUs
                  • Egress achieved
                  • Low operating forces
                  • Carrier design provides static friction
                    (eliminates sash drift)
                  • Patents: see link above

Static Friction Inverted Series

SFI Series Intro.

Static Friction Inverted Series

SFI Series Features Comparison

SFI Field Service Demo

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™ Balance System offers:

                  • a lower price
                  • significantly reduced operating forces
                  • a substantial reduction of on-hand inventory
                  • dramatically smaller space requirements
                  • a tighter fitting sash
                  • Patents: see link above

SideLoad Balance System

SideLoad Balance NEW FEATURES

SideLoad Balance System

SideLoad Balance Intro.

SideLoad Balance System

SideLoad Installation Instructions

SideLoad System Sash Cam

Sash Cam Dimensions & Mounting

SideLoad Balance System

Slot Milling Instructions

SideLoad Balance System

One Piece Sash Guide Instructions

SideLoad Balance System

Two Piece Sash Guide Colors

SideLoad Balance System

Spring Carrier 2-Stage Lock System

SideLoad Balance System

Field Installation Instructions

SideLoad Balance System

SideLoad Spring Selection Guide

SideLoad™ Constant Force Balance System for WOOD

SideLoad Balance for WOOD

SideLoad for WOOD Intro.

SideLoad Balance for WOOD

SideLoad for WOOD Installation Instructions

the SideLoad™ Balance System - Demo

The SideLoad™ Balance - Sash Removal & Component Review

The SideLoad™ Balance - Sash Guides & NEW Sash Cam Demo

SideLoad constant force balance system demo video
SideLoad Balance Sash Guides & NEW Sash Cam Demo

Constant Force Balance Springs

Today’s window requirements demand quality and consistency. Springs need to pull their weight…and no less.

Constant force spring characters lifting weights

Our AAMA qualified springs do just that, no matter how high the rated load.

                  • ½” Series: 3 lb. through 10 lb.
                  • ¾” Series: 3 lb. through 13 lb.
                  • ⅜” Egress Series: 4 lb. through 7 lb.

Constant Force Balance Spring

Info Sheet

Constant Force Balance Spring

1/2" Spring Selection Guide

Constant Force Balance Spring

3/4" Spring Selection Guide

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Got A Question? Consult our Experts.

Our experts offer a depth of expertise to assist you with all parts of the process. We are ready to answer your questions in a timely manner and will help you define what you need. We produce custom springs for all purposes, and we are here to work with you on any of your customization needs.

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