What is a torque limiter (overload protection device)?
2026/06/15
What Is a Torque Limiter (Overload Protection Device)? Types and Features
Table of Contents
What is a torque limiter (overload protection device)?
A torque limiter (overload protection device) is a type of coupling that instantly disconnects the input and output in the event of an overload to protect the machinery.
| Mechanism | |
|---|---|
 Rotation is transmitted within the set torque range. |  If the set torque is exceeded, the input and output are disengaged, and |
Types and Features of Common Torque Limiters (Overload Protection Devices)
The table below outlines the general features and application examples of torque limiters. We hope this information will be useful in your daily operations.
| Type | Torque adjustment | Automatic reset | No Backlash | Torque Range [N·m] | Applications |
|---|---|---|---|---|---|
| Key type | ○ | 0.2–200 | Conveying machinery, printing machinery, machine tools, hydraulic and pneumatic pumps, power transmission equipment | ||
| Ball and spring type | ○ | ○ | 7–3200 | Packaging Machinery, Food Processing Machinery, Presses, Conveyors, Water Gates, Machine Tools, Textile Machinery, Industrial Robots, Printing Machinery, Packaging Machinery | |
| Roller/Spring Type | ○ | ○ | 0.35–5000 | Indexing devices, various automated machines | |
| Friction type | ○ | ○ | 0.1–30 | Conveying machinery, office automation equipment (small diameters only), printing machinery (bag-making and filling machines, small box packing machines, vacuum packaging machines), food processing machinery (flour milling machines, noodle-making machines, bread-making machines, beverage processing machinery) | |
| Break-pin type | 500–35,000 | Conveying machinery, large conveyors, power transmission machinery | |||
| Plate/Spring Type | ○ | 0.3–3.0 | Tension control, laminators, bolt tightening machines | ||
| Magnetic type | ○ | 0.1–12 | Food machinery and high-precision equipment | ||
| Eddy current type | ○ | 0.02–1 | Printing machines, packaging and filling machines, measuring instruments, capping machines |
Miki Pulley Torque Limiter Product Lineup
Miki Pulley's torque limiters are available in the following lineup. The features and details of each model are presented in a table.
| Model | Types | Features | |
|---|---|---|---|
| Torque Tender TT(01) | Key-type two-shaft mating type |  | A two-shaft butt-type coupling that transmits power and protects machinery from overload by inserting two shafts from both ends (housing and hub) and securing both shafts with set screws. Because it is a two-shaft butt-type coupling, it can also be used as a flexible coupling. ・Set torque: 0.2–200 N·m ・Suitable shaft diameter: 8–50 mm |
| Torque Tender TT(03) | Key-type Wrap-around Type |  | A wrap-around type that transmits power and protects machinery from overload by inserting a shaft into the inner diameter (hub) and mounting a pulley, sprocket, or gear onto the outer diameter of the housing. Since the shaft is secured at the center of the unit, it can be installed even on shaft ends that cannot be configured as through-shafts. ・Setting torque: 0.2–200 N·m ・Compatible shaft diameter : 8–45 mm |
Miki Pulley: How the Torque Limiter Works
When overloaded, the drive key disengages against the torque spring force, disconnecting the input and output to protect the machinery. When the rated torque is reached, it automatically reengages at the same position to resume power transmission.
*The video shows the operation during an overload with the output directed toward the housing (outer perimeter).
Case Studies of Miki Pulley Torque Limiters
Pump (valve actuator)
Used as overload protection for valve operation
Sluice Gate Operating Mechanism
Used as overload protection for the manual handle.
Conveyor (Conveying Drive Unit)
Used as overload protection for the drive gear motor; Used to prevent chain breakage.
printing press
Used to control the tension of printed materials.
Small valve
Used to prevent over-tightening of the valve.
Customization Examples of Miki Pulley Torque Limiters
At Miki Pulley, we offer a wide range of custom and made-to-order products, and we can accommodate customization requests for nearly all of our products.
Customization Examples: Ultra-Thin
This is a custom model for game console steering wheels. It features a slim profile and allows for different torque settings on the left and right sides.
Customization Examples: Ultra-Compact
This is a custom model designed for office automation equipment. It offers a space-saving design while supporting high torque and high rotational speeds.
Torque Limiter (Eccentricity-Tolerant Type) Customization Examples: Eccentricity-Tolerant Type
This is a customized model based on the overload protection mechanism of a continuously variable transmission (CVT). Torque can be adjusted by the amount the cover is screwed in.
Customization Example: Differing Torque on Left and Right Sides
This is a customizable model that allows for different torque settings depending on the direction of rotation. You can apply protection separately for the handle and the direction of rotation.
When it comes to torque limiters, leave it to Miki Pulley!
"I’d like to hear just a brief explanation of the benefits of installing a torque limiter in our equipment."
"We’d like to review the torque limiters we’re currently using..."
"We don’t know anything about the design, so we’d like you to help us select the right one."
If you have questions or requests like those listed above, please feel free to contact us using the inquiry form below. Our technical
staff will propose and explain the torque limiters best suited for your equipment.
