In industrial power transmission, few components are as widely used — or as widely misunderstood — as locking assemblies. Whether you hear them called Tollok, Tollock, locking bushes, keyless bushings, or shrink discs, they all refer to the same core idea: a mechanical device that creates a friction‑based, backlash‑free connection between a shaft and a hub.
Although Tollok® is a brand owned by Regal Rexnord, the name has become so common in industry that many engineers simply use “Tollok/Tollock” as a generic term. RR Fisher supplies equivalent locking assemblies that match these industry‑standard TLK designs.
This article explains what Tollok locking assemblies are, how they work, where they’re used, and which TLK‑style units RR Fisher keeps in stock.
What Is a Tollok / Tollock Locking Assembly?
A locking assembly is a keyless shaft‑hub connection that transfers torque using friction rather than traditional keys, splines, or taper‑lock bushes. When the locking screws are tightened, the inner and outer rings clamp against the shaft and hub, creating a uniform, secure interference fit.
Why industry loves them:
· Zero backlash
· High torque transmission
· Even surface pressure
· Reduced stress compared to keyed connections
· Quick installation and removal
· Perfect for cyclic loads, reversing loads, and shock loads
Locking assemblies have been industry leaders for more than 35 years and are interchangeable with other global brands like MAV, Chiaravalli, TAS, and B‑LOC.
Where Are Locking Assemblies Used?
Locking assemblies appear throughout heavy industry, including:
· Conveyors and material handling
· Pumps, fans, and blowers
· Gearboxes and speed reducers
· Mining and quarry machinery
· Food processing equipment
· Energy, forestry, and aggregates
Their ability to handle misalignment, vibration, torque spikes, and high loads makes them ideal for demanding environments.
Popular Series (Industry Standard)
Below is a simple guide describing key locking assembly models commonly referenced in New Zealand and Australian industry. (These descriptions are based on the Rexnord Tollok product range.)
TLK110 – Compact, self‑centering
· Medium–high torque
· Restricted radial footprint
· Used where space is limited
TLK130 – High torque / self‑centering (One of the most common Tollok models)
· Available 18–240 mm shaft sizes
· Fast installation
· Suitable for sprockets, gears, timing pulleys
· Similar to TLK130 but optimised for lower surface pressures
TLK132 & TLK133 – Medium‑high torque
· Self‑centering
· Alternative to TLK200 in many applications
· Used for hubs requiring lower pressures
TLK200 – Wide tolerance / not self‑centering
· Very versatile unit
· Accepts wider machining tolerances
· Excellent for larger hubs and general machinery
· Thin design for restricted spaces
· Suitable for lighter applications
TLK350 – Medium‑high torque / easy installation
· Uses fewer screws
· Used for light industrial shafts and smaller equipment
TLK400 – Very high torque / heavy‑duty
· Designed for bending loads
· No axial movement during tightening
· Used on large pulleys, crushers, and industrial drives
TLK450 – Very high torque / premium series
Reinforced design for severe shock loads
Heavy machinery, mining, primary metals
· Medium Torque
· Quick Installation and dismantling
· RR Fisher’s Locking Assembly Range (Tollok‑Compatible)
RR Fisher stocks and supplies locking assemblies equivalent to the industry‑standard TLK series, suitable for shaft diameters ranging from small drive shafts to very large industrial hubs. Browse the RR Fisher locking assembly collection here:
https://rrfisher.co.nz/collections/locking-assemblies
RR Fisher’s stock covers the most common sizes for conveyors, processing machinery, fans, pumps and general engineering applications in New Zealand.
Why Use RR Fisher for Locking Assemblies?
Direct Replacements for Tollok/Tollock Units as well as covering other brands including B‑LOC, MAV, Chiaravalli, TAS, Ringfeder locking assemblies
· Our units follow the same tapered locking design principles used in TLK‑series assemblies.
Fast Availability
· We carry the core industrial sizes used in NZ manufacturing, food processing, forestry, and quarrying.
Local Support
· Technical selection help available — including torque calculations, bore sizes, and interchangeability.
Cost‑Effective
· Equivalent performance without long lead times or international freight.
How to Select the Right Locking Assembly
When choosing a locking assembly, you will need to determine your requirements:
· Shaft diameter (d)
· Hub outer diameter (D)
· Required torque (Nm)
· Surface pressure limits (pₙ)
· Whether the hub requires a self‑centering or non‑centering unit
· Whether axial movement during clamping is acceptable
If you’re replacing an existing unit, simply supply the model number (e.g., TLK130‑100×145 or TLK200‑55×85) and we’ll provide the direct equivalent.
Conclusion
Tollok (or “Tollock”) locking assemblies have become a global standard for secure, backlash‑free shaft connections. Their TLK‑series designations — TLK130, TLK133, TLK200, TLK350, TLK400, TLK450, TLK603 and more — are widely recognised across industry.
RR Fisher supplies a comprehensive range of Tollok‑compatible locking assemblies right here in New Zealand, giving you fast access, competitive pricing, and technical support without needing to import.
If you need help specifying the right unit for your application, feel free to reach out — happy to assist with torque calculations, replacements, or upgrades.