AROFLEX Torque Limiter Technical Guide

Complete reference for installation, running-in, limit switch integration, machining tolerances and product data for ATL friction disc, chain coupling, elastomeric, and shear torque limiter ranges.

Section 1

Installation Instructions for ATL Torque Limiters

Before assembly, ensure all components are thoroughly cleaned and inspected. Follow the sequence below precisely.

1

Fit the Pilot Bush

Slide the bronze pilot bush onto the torque limiter hub.

2

First Friction Facing

Slide the first non-asbestos friction facing over the hub so it sits flush over the bush.

3

Mount Centre Member

Mount your centre member (platewheel, sprocket, or pulley) onto the bronze bush.

4

Second Friction Facing

Slide the second friction facing on, ensuring it sits squarely on the bush against the centre member.

5

Pressure Plate

Install the steel pressure plate.

6

Disc Springs

7

Adjusting Nut

For standard models, fit the pilot plate or lock-washer, then thread on the adjusting nut.

Section 2

Mandatory Running-In Procedure

Friction torque limiters must be run-in to burnish the friction discs and achieve consistent, accurate slip torques.

70-80%

of max single-spring capacity

60 RPM

forced slip rate

4 min

burnish duration

Caution: Never completely flatten the disc springs when adjusting to final slip torque.

Section 3

Use and Installation of Limit Switches

Friction limiters are mechanical fuses - they do not stop the driving motor. Left to slip during a jam, they generate extreme heat that will glaze friction facings or create a fire risk.

SELECTION

EM1 vs EM2

Use EM1 (Inductive Proximity) for clean or dusty areas. Use EM2 (Mechanical Plunger) for heavy washdown zones such as bakery conveyors.

MOUNTING

Actuation Plate

Position the switch to interact with the limiter's axial actuation plate. For the EM2, the plunger should be depressed by 1-3mm immediately on a trip.

WIRING

Fail-Safe (NC)

Always wire using Normally Closed (NC) contact logic. If a wire is severed, the circuit opens and instantly stops the motor.

Technical Reference

Critical Machining Tolerances

To ensure the AROFLEX unit operates effectively without vibration or premature failure, adhere to these strict standards.

Shaft Bore (H7 / JS9) H7 precision transition fit to eliminate wobble, paired with a JS9 snug-fit keyway to prevent the key rolling.

Centre Member Bore (H8) Sprocket or pulley machined to H8 to perfectly match the ATL's pilot bush diameter.

Bronze Bush Thickness Centre member width must exactly match bush length. Too thin won't clamp; too thick won't assemble.

Surface Finish

Cleanliness Friction surfaces must be free of oil, grease, dirt and rust. Moisture and corrosion alter the friction coefficient and ruin the unit.

Product Range

AROFLEX Product Specifications

Full dimensional and torque capacity data for every AROFLEX torque limiter and coupling family. Select a product range below.

Chain Coupling

AROFLEX ATLC

Torque limiter combined with duplex roller chain flexible coupling. Eleven standard sizes combining overload protection with in-line shaft connection.

2.94 - 10,000 Nm

Elastomeric Coupling

ATL RN & ATL RB

Elastomeric torque limiter couplings in JAW (RN) and Pin & Bush (RB) configurations. Smooth power transmission with built-in overload protection.

2.94 - 1,088.54 Nm

Shear Coupling

SRB & NFS Shear

Positive disconnect shear torque limiter couplings in Pin & Bush (SRB) and Jaw (NFS) types. Wedge pin ratings adjustable to precise torque values.

331 - 23,000 Nm

Chain Coupling

AROFLEX ATLC - Torque Limiter Chain Coupling

Torque limiter combined with duplex roller chain flexible coupling. Eleven standard sizes. All dimensions in mm.

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Elastomeric Coupling

ATL RN (JAW) & ATL RB (Pin & Bush)

Elastomeric torque limiter couplings in JAW and Pin & Bush configurations. All dimensions in mm.

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Shear Coupling

SRB (Pin & Bush) & NFS (JAW) Shear Torque Limiter

Positive disconnect shear couplings up to 23,000 Nm. Torque adjustable by Wedge Pin ratings.

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Installation & Maintenance

ATLC Torque Limiters - Installation & Maintenance Guide

Official Arrow Engineering guide covering assembly, running-in, torque setting, checking, couplings and maintenance. Models ATLC 14 to ATLC 64.

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Upgrades

Alternative Technologies

Option 1

Indent Ball Limiters

e.g. Mayr EAS Compact / Compomac ZBC. Spring-loaded balls in detents pop out under overload for instant mechanical disconnect.

Advantages

Zero-backlash precision and instant disconnect with no heat.
Synchronous re-engagement at exact 360° home position.
Sealed stainless (EAS-Compact-R) for hygienic washdown.

Disadvantages

Will clatter continuously if the motor isn't switched off - a limit switch is mandatory.

Option 2

Positive Disconnect Limiters

e.g. Wedgegard / Shear Pin. A hardened wedge or pin physically shears at a precise torque to completely disconnect the drive.

Advantages

Absolute circuit breaker - motor spins free with zero heat.
Highly accurate torque precision (±5%).
Handles extreme torques up to 125,000 Nm.

Disadvantages

Reset is manual and consumable. Operator must replace the broken wedge pin - unsuitable for frequent nuisance jams.