AROFLEX ATL Friction Disc Torque Limiter 25-1

AROFLEX ATL25-1 Friction Disc Torque Limiter

Heavy-Duty 1-Spring Slip-Type Torque Protection for Industrial Drives

The AROFLEX ATL25-1 is a robust, reliable friction disc torque limiter designed to protect industrial drive systems from overloads, shock loads and machine jams.

It works as a mechanical fuse within the drive system. When the driven machine exceeds the pre-set torque value, the spring-loaded friction facings allow the centre member to slip rather than passing the overload directly into the gearbox, motor, shaft or connected equipment.

The “-1” designation refers to the single-disc spring configuration, giving the ATL25-1 the lower torque range within the ATL25 model size. This makes it well suited to applications where controlled slip protection is required without moving into the higher torque setting of the 2-spring or 3-spring versions.

Because the ATL25-1 is a slip-type torque limiter, the drive remains connected during an overload. This makes it ideal for applications where short nuisance jams, temporary blockages or high-inertia starts may occur without always needing a full mechanical reset.

Key Features

Reliable overload protection

The ATL25-1 helps protect expensive drive components by slipping when the set torque is exceeded, reducing the risk of damage to gearboxes, motors, shafts, sprockets, pulleys and driven equipment.

1-spring torque setting

The ATL25-1 is supplied with a single-disc spring arrangement, giving the lower adjustable torque range within the ATL25 series.

Fully adjustable and resettable

Torque is adjusted using the 60mm A/F adjusting nut, allowing the ATL25-1 to be set to suit the application. Once the overload is cleared, the drive can continue without replacing shear pins or sacrificial components.

Compact heavy-duty design

With an 89mm outside diameter and 25mm maximum bore, the ATL25-1 is well suited to heavier chain drives, pulley drives, conveyors, handling equipment and industrial drive assemblies where reliable overload protection is required.

UK-machined ready-to-fit options

AROFLEX ATL25-1 units can be supplied fully machined to suit your shaft size, including bore and keyway machining. Units can also be supplied pre-assembled with a platewheel, pulley or coupling arrangement where required.

Typical lead time for bespoke machined, ready-to-fit units is 3 to 5 working days.

Compatibility reference

The ATL25-1 may be suitable for applications using Morse 350M1 style friction torque limiters, subject to dimensional and torque-range checks.

The Morse name is used for identification and compatibility reference only. AROFLEX products are not manufactured, approved by, or affiliated with the respective trademark owner.

Technical Specification

Sprocket, Pulley & Coupling Compatibility

The ATL25-1 can be used with sprockets, pulleys or coupling arrangements depending on the drive layout.

For chain drive applications, the recommended sprocket / platewheel sizes are:

These sizes help provide clearance around the torque limiter adjustment springs. The ATL25 may also be suitable with 08B-25T or 10B-21T platewheels where required, but using 08B-26T avoids the need for a crank link.

The ATL25-1 can also be used with:

For inline shaft-to-shaft applications, the ATL25-1 can be supplied with a compatible ATLC 25 chain coupling, ATLR 25 rubber/jaw coupling or RNTL125 elastomeric jaw coupling arrangement. This allows the torque limiter to act as both the shaft connection and overload protection device.

The maximum secondary coupling bore is listed as 60mm for ATLC / ATLR 25 and 55mm for RNTL125.

Precision Machining Matters

Every AROFLEX ATL25-1 hub is machined to support a secure and accurate shaft fit.

The bore is machined to an H7 Precision Transition Fit, with a JS9 keyway tolerance. This helps reduce shaft movement, key-roll, vibration and the mechanical “shucking” that can occur when the bore or keyway fit is too loose.

For customers who want a unit ready to install, we can supply the ATL25-1 fully machined to your shaft size and pre-assembled with the required centre member.

Typical lead time for bespoke machined, ready-to-fit units is 3 to 5 working days.

If fitting your own centre member, such as a platewheel, pulley or gear, the centre member must be bored to suit the 60mm ATL pilot diameter at H8 tolerance. The friction contact faces should be finished correctly and kept parallel to ensure reliable slip performance and even friction disc wear.

Running-In Procedure

For the most consistent torque setting and friction performance, the ATL25-1 should be run in during installation.

Before running-in, ensure the friction facings and centre member are free from oil, grease, dirt and rust.

The unit should typically be adjusted to approximately 70–80% of its maximum single-spring capacity, then the centre member should be forced to slip at around 60 rpm for 4 minutes.

Running-in helps bed the friction surfaces and supports more consistent torque performance once the limiter is in service.

Important Safety Note

The ATL25-1 is designed to slip during an overload, but it should not be allowed to slip continuously for long periods.

If the unit may slip for more than 5 to 10 seconds, an automatic motor shut-off system should be fitted, such as an EM1 or EM2 limit switch.

Continuous slipping can generate extreme heat and may damage the friction facings, centre member or surrounding equipment. In severe cases, prolonged slipping can create a fire risk.

For applications where a jam may not clear immediately, we strongly recommend pairing the torque limiter with a limit switch to stop the motor automatically.

Typical Applications

The AROFLEX ATL25-1 is suitable for medium-to-heavy duty drive protection applications, including:

Need Help Selecting the Right Torque Limiter?

If you are replacing an existing torque limiter or selecting one for a new application, we can help confirm the correct size, torque range, bore, keyway and drive arrangement.

For best selection, please provide:

Motor power, gearbox output speed, shaft diameter, chain or pulley size, and details of what the machine is driving.