The Complete Guide to Torque Hinges
We’ve put together this resource to give you insights into the functionality, applications, and benefits of torque hinges. You’re already familiar with traditional hinge characteristics, but what makes torque hinges different as door hinges? Why are they used across different applications, from access panels and furniture hinges to hinges for heavy doors? We’ll explain their role in industrial hardware and help you explore your options, covering:
What Are Torque Hinges?
The primary function of a torque hinge is to hold an object in a desired position and provide resistance against rotation. Free-swinging hinges, such as lift-off hinges and some butt hinges, allow unrestricted movement. Torque hinges instead incorporate internal mechanisms that create a controlled torque or resistance to rotation.
How do torque hinges work?
They typically consist of two main hinge components: a cylindrical barrel and a central pivot. The barrel houses the internal mechanism, which includes a combination of springs, friction plates, and damping elements. These components work together to generate the desired torque, or predetermined angles.
When a torque hinge is installed between two objects and its base, such as an access panel, the torque generated by the internal mechanism opposes the rotational force, or pivoting motion, applied to the hinge. This creates a controlled resistance that allows the object to be positioned at different angles and held securely in place. The amount of torque can often be adjusted by changing the internal components or settings of the hinge.
Torque hinges vs. friction hinges
Torque hinges are sometimes referred to as friction hinges. Friction hinges describe hinges that provide resistance to rotation through the use of frictional forces. A friction torque hinge typically incorporates friction elements, such as plastic washers or polymer pads, which create resistance against movement when two surfaces come into contact. This frictional force generates the desired torque, allowing for controlled and smooth rotation of the hinge. So, while torque hinge is the more general term, friction hinges specifically rely on friction for resistance.
What are the Advantages of Torque Hinges?
Torque hinges’ efficiency is one advantage over traditional hinges, such as butt hinges and spring-loaded hinges. When adjusted, the positioning torque stays consistent throughout the full range of motion, preventing the object from abruptly falling or closing. They also allow for precise positioning of the object at different angles, enabling ergonomic adjustments and improved user experience, without the need for gas struts. Torque hinges can also be designed to hold an object at any angle within a specified range, providing flexibility and versatility in various applications.
Types of Torque Hinges and Their Applications
Below are some common examples of torque hinges and what they’re used for.
Adjustable Torque Hinges – Leaf Screw
With a maximum rotation of 180 degrees, this adjustable torque hinge operates with a single torque adjustment screw. Surface mounted.
Adjustable torque hinges typically used for: Panels and covers for industrial machinery and equipment. Doors and panels for industrial enclosures.
Constant Torque Hinge – Position Controlled
The constant torque hinge, also known as a positioning hinge or pivot hinge, articulates and holds panels in position, eliminating the need for gas struts or lid stays. Constant torque hinges feature a constant rate of torque throughout their range of motion – hence why they're also called constant torque friction hinges.
Constant torque hinges are typically used for: Medical equipment, such as adjustable stands, monitors, and diagnostic devices. Also, lightweight cabinet and enclosure doors.
Adjustable Torque Hinge – with Pin Screw
Also known as a friction hinge, this heavy-duty adjustable torque hinge provides resistance to the pivoting motion. The hinge articulates and holds the application in position, allowing you to adjust the torque exerted on the hinge.
Heavy-duty adjustable torque hinges typically used for: Bonnets, lids, access panels, hatch covers and display devices.
To learn about hinge types in general and their applications, see our guide, Types of Hinges and Where to Use Them.
Selecting the Right Torque Hinge for Your Project
First, let’s understand torque. This is the energy or effort required to move a door or panel from a closed position to an open position. Choosing the appropriate hinge with the right torque profile involves three key factors:
- Weight: For lightweight panels weighing only a few pounds, a simple hinge with no torque provides a cost-effective solution. However, as the weight of the door or panel increases to about 15 to 20 pounds, hinges with constant torque become more effective in preventing the door from falling while requiring some user force.
- Center of gravity: The center of gravity of a door or panel is influenced by factors such as its width, shape, and the presence of additional attached components. Even a lightweight door with the center of gravity positioned further from the hinge point may require more torque to lift compared to a heavier door with the center of gravity closer to the hinge point.
- Direction of movement: Consider whether the panel or door is hinged vertically or horizontally. Vertical hinges that move from side to side do not face the same gravitational challenges as horizontally hinged panels that require upward or downward movement. In some cases, a horizontally hinged door may need to be held in a vertical position, allowing technicians to access and work on the application. Transitioning from a horizontal to vertical position requires additional energy. In these scenarios, constant torque friction hinges are often more suitable, especially when working under an overhead door that needs to remain open.
How to calculate torque
To calculate the torque required for a hinge, follow these steps:
1. Determine the weight: Measure or determine the weight of the object that the hinge will support. Make sure to use consistent units of measurement, such as pounds or kilograms.
2. Find the distance to the center of gravity: Identify the location of the center of gravity of the object. This is the point where the weight can be considered to be concentrated. Measure the distance from the hinge to the center of gravity. Again, use consistent units of measurement, such as inches or centimeters.
3. Calculate the torque: The torque required can be calculated using the following formula:
Torque (τ) = Force (F) × Distance (d)
Where:
- Torque (τ) is measured in units of force multiplied by distance (e.g., Newton-meters or pound-inches).
- Force (F) represents the perpendicular force applied to the hinge, typically measured in units of Newtons (N) or pounds (lbs).
- Distance (d) is the distance between the hinge pivot point and the line of action of the force, typically measured in meters (m) or inches (in).
It's important to ensure that the force and distance values are measured in consistent units. The force should be applied perpendicular to the hinge to accurately calculate the torque.
4. Consider the desired angle or range of motion: If you have a specific angle or range of motion in mind for the hinge, you may need to adjust the torque calculation. Note, different angles may require varying torque to hold the object in place or facilitate its movement. Consult the hinge manufacturer's specifications or guidelines for specific torque requirements at different angles.
Note, this is a general method, and actual torque requirements may vary based on the specific hinge design, frictional forces, and other factors. For critical or complex applications, always consult with the hinge manufacturer for precise torque calculations and appropriate hinge selection.
For more help in selecting the right hinge, see our guide, How to Size Hinges.
Why Torque Hinges Are an Essential Piece of Industrial Hardware
Overall, different types of torque hinges provide controlled motion, positioning capabilities, load management, versatility, and durability, making them an essential hardware component in different industrial settings. They enhance safety, efficiency, and user experience, contributing to the smooth operation of doors, panels, and other components in industrial machinery, equipment, and infrastructure.
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