How to Build a Custom Spring Counterbalance Hinge With the Vectis App

Off-the-shelf solutions don’t fit every design. To improve user experience, resolve a safety issue, or stand out from competitors, everything you put into your product design should fit like a glove.

That’s why we allow you to tailor Weber Knapp’s four Vectis counterbalance hinge sizes -- to give your project the precise torque it needs. The quickest (and maybe the most fun) way to do this is with the Vectis online app. Using the intuitive app, you can create a custom spring counterbalance hinge in minutes and save it for our engineers to review.

The following five steps will show you how to do that.

Remember: Vectis experts can assist you at any stage of your design. So if this all feels like too much and you need to step back, tag us in!

5 Steps to Building a Custom Spring Counterbalance Hinge

(Watch the video above for a step-by-step walkthrough on using the Vectis app.)

1. Figure out Your Starting Specs

To get started with the Vectis™ DYO app, you’ll need to plug in the three critical parameters of the load to be counterbalanced:

(Note: we use “lid” frequently below, but the same information applies to whatever you’re looking to support, whether that’s a door, cover, or other load.)

Lid Weight

Determining the weight of your lid is simply a matter of removing the entire lid or rotating load, if it already exists, and weighing it using a high-quality scale. Alternatively, a modern CAD system can easily predict both weight and center of gravity within your design quite reliably before your device is even built. 

Lid Center of gravity

Here’s where you get the second and third critical stats of your load. For the purposes of the app, we’re referring to the center of gravity when your lid is closed.

The easiest way to find this is to simply send your lid design to us. We have a tried-and-true method in which we take force readings at different angles. We use that information combined with our proprietary software to determine your design’s center of gravity.

We find customers get far better results when we take the measurements ourselves, but we’ve also shown customers how to do it. Or, if you insist on finding the center of gravity yourself, you can try one of the methods here. 

The “Distances” in the second and third boxes under Parameters refer to the location of your load’s center of gravity (C.G.) relative to the pivot axis when your load is in the 0° (closed or lowest) position.

2. Pick a Vectis Hinge

Now let’s set things in motion! Select a Vectis model -- 200, 600, 1200, or 1800 -- and how many you need. All Vectis counterbalance spring designs allow up to 90° of rotation.

Use the slide bar variables in the app to get the optimum torque curve and fine-tune the open/close feel.

Based on the values entered in Step 1, the Vectis app automatically calculates the approximate torque required to lift your load from its closed position. It displays this value in the Required Torque text box.

The graphic on the right updates as you change parameters so you’re not purchasing anything blindly. You can use the Required Torque value to make an initial guess about which Vectis counterbalance hinge model might be appropriate and how many hinges each lid requires.

3. Determine How Many Hinges You Need

A typical lid will require two or more hinges to provide adequate mechanical support that keeps users safe and happy. Occasionally, one hinge will do for a light or narrow load. 

You should weigh several factors when deciding on the number of hinges for each lid. These include mounting considerations -- for example, if your hinges must support the middle of an unusually long lid, keep that in mind. Very large lids can require several Vectis hinges just to provide the spring energy needed to counterbalance that weight.

Be careful to keep the pivot axis center lines of multiple hinges aligned.

4. Try out the Counterbalancing Action You Want

The orange Spring Torque Curve line on the app’s graph represents the spring-based opening torque applied by your hinges. By inputting or adjusting a few additional parameters on the app, you can position the orange line above, on, or below the black line at different angles. This helps you control the amount of spring-based torque that’ll be applied to counteract your lid at each angle.

The lighter orange lines give you a rough idea of the controlled friction band built into your hinge. There’s a little bit of friction inherent to all hinges. This friction helps hold your load in place. In areas where the black lid torque line is between the light orange lines, the lid or load will stay put.

Remember: All inputs are interactive, so changing one value in the app may alter or limit other values. It’s important to evaluate multiple design combinations before choosing the best solution. Experiment!

5. Designate the Built-In Open Stop Angle

In the Lid “open stop” Angle input box, simply type in the open stop angle desired.

Not all hinge applications require 90° of rotation. You can instead specify an open stop angle between 45° and 90°. This angle will be permanently cut into your hinge when it is manufactured. 

There are many situations where a limited angle makes sense. Examples include keeping a lid’s handle within convenient operator range or avoiding obstacles in the area of your rotating load. You also may wish to prevent an uncontrolled “float open” condition. Limiting pointless movement might allow internal spring resources to be allocated for better counterbalancing in a more critical area of lid rotation. 

Variable A and B represent geometry that’ll be permanently cut into the internal linkage of your hinges. The spring settings dictate the initial spring adjustment made at the factory. The unique result of these three numbers tailors your hinge to your needs. The result is reflected on the orange Spring Torque Curve line.

At angles where the spring torque is higher than the lid torque, the lid will self-open. When the spring torque is lower, the lid will self-close.

The built-in open stop is more than capable of withstanding normal spring and static weight loads. However, if you expect high external or inertia-based loads in your application, added external support is a must.

When You’re Done

When you’re completely satisfied with your custom-made design, you can register it by providing a project file name, other required information, and your username. Once you’ve saved your design, Weber Knapp will provide you with a screenshot of the torque curve.

(Still struggling to finish your design on the app? This PDF provides additional examples and graphics of how to use it.)

After you’ve finished your design and registered an account, a member of the Weber Knapp team will be in touch via email. This initial contact will include a price quote and a production time estimate.

For more information, questions, or for help with our app, contact us. Otherwise, get started by clicking below!

(Editor's Note: This blog was originally published in July 2019 and was recently updated.)