Keyless Locking Assemblies
Internal keyless locking assemblies between shaft and hub for pulleys, gears, sprockets, couplings and drums, plus keyless rigid shaft joints and high bending moment connections.
Keyless Locking Assemblies
Internal keyless locking devices fitted between shaft and hub - self-centering and non-self-centering designs for pulleys, gears, sprockets, couplings, drums and flywheels. Reference ranges: SIT-LOCK (SIT S.p.A.), Rexnord Tollok and RINGFEDER.
Keyless Locking Assembly Families
SIT-LOCK (SIT S.p.A.)
Italian keyless locking devices: self-centering series 3-20 and MONOLOCK, non-self-centering series 1, 2, 9.
View Product →
Rexnord Tollok
TLK110-TLK450 locking assemblies from 5 to 900 mm, medium to very high torque.
View Details →
RINGFEDER
RfN 7003-7515 locking assemblies, 6 to 1000 mm, including stainless-steel versions.
View Details →
SIT-LOCK 10 - Rigid Shaft Joint
Two tapered rings and a split inner ring for clamping two shafts with medium-high torque.
Request a Quote →
Rexnord Tollok TLK500 - Rigid Coupling
Keyless rigid shaft coupling for medium torque, 14-80 mm; quick installation and dismantling.
Request a Quote →
High Bending Moment Devices
Selections for drum pulleys and similar duties combining torque and bending moment (series 1, 4, 4C, 7, 20, 22).
Request a Quote →
Customised Versions
Special locking devices designed on request for non-standard dimensions or loads.
Request a Quote →Rexnord Tollok
Brand: Rexnord Tollok (Regal Rexnord, Italy / USA)
| Series | Centering | Torque | Shaft range | Main feature |
|---|---|---|---|---|
| TLK110 | Self-centering | Medium-high | 6-140 mm (1/4"-4 15/16") | Low surface pressures |
| TLK111 | Self-centering | Medium | 14-65 mm | Restricted radial space |
| TLK130 | Self-centering | High | 20-220 mm (3/4"-4") | Quick installation; excellent perpendicularity |
| TLK131 | Self-centering | Medium-high | 20-220 mm (3/4"-4") | Low surface pressures; excellent perpendicularity |
| TLK132 / TLK139 | Self-centering | Medium | 20-220 mm / 18-90 mm | Compact |
| TLK133 / TLK134 | Self-centering | Medium | 20-220 mm / 14-50 mm | Compact |
| TLK136 | Self-centering | High | 100-600 mm | High bending-moment capacity |
| TLK138 | Self-centering | Medium-low | 6-35 mm (1/4"-1 3/8") | For inch hub bores |
| TLK200 | Not self-centering | Medium | 19-900 mm | Self-releasing; compact |
| TLK250 / 250L | 250: not / 250L: self-centering | Low | 14-70 mm | Quick installation |
| TLK300 | Not self-centering | Low | 5-540 mm | Compact; self-releasing |
| TLK350 | Self-centering | Medium-high | 6-50 mm | Quick installation |
| TLK400 / 401 | Self-centering | Very high | 45-400 mm / 70-340 mm | Even pressure distribution |
| TLK450 / 451 / 452 | Self-centering | Very high | 25-400 mm / 70-600 mm | Economical very-high-torque design |
Source: Rexnord Tollok catalog PT2-001 (2017). Check the current Regal Rexnord documentation for the latest ratings and dimensions.
For a quotation send: shaft diameter, hub bore and outside diameter, hub material, torque / power and speed, axial force and bending moment, existing device code if any.
Information only, based on manufacturer literature; brand names belong to their owners. MECHATRIC does not represent this manufacturer and supplies original or equivalent products after dimensional and rating check.
RINGFEDER
Brand: RINGFEDER (Germany)
| Series | Torque range (Nm) | Shaft d (mm) | Main feature |
|---|---|---|---|
| RfN 7003 | 355 - 512,635 | 19 - 400 | Two-piece, slit, single taper; tolerates larger tolerances; reinforced flange; high speeds and radial loads. |
| RfN 7004 | 530 - 63,903 | 19 - 180 | Extended RfN 7003 with low hub pressure - allows small hub outside diameters. |
| RfN 7005 | 649 - 1,760,000 | 25 - 600 | Three-piece, self-centering, long flat cone for heavy-duty torques. |
| RfN 7006 | 270 - 375,945 | 19 - 400 | As RfN 7003 with larger flange - no hub axial displacement; used with belt pulleys. |
| RfN 7007 | 320 - 48,800 | 19 - 200 | Self-centering; excellent concentricity; easy dismantling. |
| RfN 7012 | 306 - 2,352,018 | 19 - 1000 | Slimmest design for limited space; large forces and moments; compensates small tolerance deviations. |
| RfN 7012.2 | 12,074 - 1,631,741 | 130 - 800 | Large sizes; self-releasing. |
| RfN 7013.0 / 7013.1 | 285 - 28,500 | 19 - 150 | Self-centering; excellent concentricity; easy dismantling. |
| RfN 7014 | 4,130 - 245,000 | 60 - 300 | Heavy-duty design. |
| RfN 7015.0 / 7015.1 | 6,575 - 2,427,520 | 100 - 800 | Long flat cones for maximum torque and axial force. |
| RfN 7061 | 6 - 1,900 | 6 - 50 | Low surface pressure for thin-walled hubs; very small shafts; very good concentricity. |
| RfN 7110 | 30 - 23,700 | 8 - 130 | Low surface pressure; compact for narrow spaces. |
| RfN 7515 | 4,299 - 1,300,152 | 60 - 640 | Long flat cones - torque, axial force and bending loads in one device. |
Stainless-steel versions: RfN 7012 (19-150 mm), RfN 7013.1 (19-150 mm), RfN 7061 (6-50 mm) and RfN 7110 (8-50 mm). Source: RINGFEDER Locking Assemblies Product & Tech Paper EN 06.2025. Torque ranges cover the smallest to largest size of each series.
For a quotation send: shaft diameter, hub bore and outside diameter, hub material, torque / power and speed, axial force and bending moment, existing device code if any.
Information only, based on manufacturer literature; brand names belong to their owners. MECHATRIC does not represent this manufacturer and supplies original or equivalent products after dimensional and rating check.
What is a keyless locking assembly?
A keyless locking assembly is a set of tapered rings fitted between shaft and hub. Tightening the clamping screws pushes the tapers together, expanding the outer ring against the hub and contracting the inner ring onto the shaft. The resulting contact pressure transmits torque and axial force by friction - without a key or keyway.
Compared with feather keys, keyless locking avoids keyway stress concentration and fretting corrosion, is backlash-free under alternating loads, allows free axial and angular positioning and is easy to remove.
SIT-LOCK Internal Locking Device Series (SIT S.p.A.)
| Series | Centering | Main feature / typical use |
|---|---|---|
| SIT-LOCK 30 MONOLOCK | Self-centering | Single ring with one tapered screw - very compact. |
| SIT-LOCK 3 | Self-centering | Low hub pressure; for aluminium hubs or hubs with lower mechanical properties. |
| SIT-LOCK 20 | Self-centering | High torque with optimised pressure distribution; sliding within the cones. |
| SIT-LOCK 4 / 4A / 4C | Self-centering | High torque transmission. |
| SIT-LOCK 5A | Self-centering | Excellent hub-to-shaft concentricity and perpendicularity. |
| SIT-LOCK 5B | Self-centering | Excellent concentricity; also for hubs with lower mechanical properties. |
| SIT-LOCK 6 | Self-centering | Good concentricity and perpendicularity. |
| SIT-LOCK 7 | Self-centering | Excellent concentricity; for hubs with limited width. |
| SIT-LOCK 8 | Self-centering | Same hub outside diameter for different shaft sizes; quick installation. |
| SIT-LOCK 12 | Self-centering | Good concentricity and perpendicularity. |
| SIT-LOCK 15 | Self-centering | Excellent concentricity and perpendicularity. |
| SIT-LOCK 16 | Self-centering | Excellent concentricity; for hubs with limited width and diameter. |
| SIT-LOCK 18 | Self-centering | For applications with high radial loads. |
| SIT-LOCK 13 | Self-centering | Ring-nut tightening - for reduced dimensions and no screw-tightening space. |
| SIT-LOCK 1 | Not self-centering | Accepts wider tolerances (h11 / H11 with reduced capacity). |
| SIT-LOCK 9 | Not self-centering | Ring-nut tightening; reduced radial and axial dimensions. |
| SIT-LOCK 2 | Not self-centering | Two tapered rings for small dimensions; needs a centering base. |
Non-self-centering devices need a separate centering seat between shaft and hub. For high bending moments (e.g. conveyor drum pulleys) SIT lists dedicated selections in series 1, 4, 4C, 7, 20 and 22.
Equivalent Series - Cross-Reference
Use this table to find the equivalent series of another manufacturer. Send the existing part number - MECHATRIC confirms the exact size and rating.
| Type | SIT-LOCK (SIT) | Rexnord Tollok | RINGFEDER | Match |
|---|---|---|---|---|
| Standard, not self-centering | SIT-LOCK 1 | TLK200 | RfN 7012 | Same dimensions (overall length may differ by 1-2 mm) |
| Self-centering, single taper | SIT-LOCK 6 / 7 | TLK133 / TLK134 | RfN 7003 (RfN 7006 with larger flange) | Same dimensions |
| Self-centering, low pressure | SIT-LOCK 3 | TLK110 | - | Same dimensions |
| Self-centering, high torque | SIT-LOCK 4 / 4A / 20 | TLK400 / TLK450 | RfN 7005 (similar) | Close - check widths |
| Self-centering, concentricity | SIT-LOCK 5A / 5B | TLK131 | - | Close - check widths |
| Self-centering, compact | SIT-LOCK 12 | TLK139 | - | Same dimensions |
| Self-centering, quick install | SIT-LOCK 15 | TLK350 | - | Same dimensions |
| Compact, not self-centering | SIT-LOCK 2 | TLK300 | - | Same dimensions |
Built by MECHATRIC by comparing shaft diameter, outside diameter and ring widths in the current SIT-LOCK (2026), Rexnord Tollok (PT2-001) and RINGFEDER (06.2025) catalogs, checked at d = 50 mm and d = 100 mm. "Same dimensions" = identical d x D and widths; "Close" = same d x D with slightly different widths. Mechanical ratings (torque, axial force, pressures, screws) can differ between manufacturers - usually only slightly - and are always checked against the duty before a replacement is confirmed.
Rating Conditions (SIT-LOCK)
- Catalogue torques are calculated with a friction coefficient of 0.12 and the stated shaft/hub tolerances (typically h8 / H8).
- Do not use molybdenum-disulphide oils or greases, which reduce friction and therefore capacity.
- Tighten screws to the specified torque in the specified sequence.
- Check the minimum hub outside diameter (Dmin) for the hub material - hub stress can govern selection.
- Combined torque, axial force and bending moment must be checked together.
Selection Procedure
Loads
Torque T = 9550 x P / n with service factor; axial force; bending moment; radial load; alternating or shock loads.
Centering requirement
Self-centering series for pulleys, gears and speed-sensitive parts; non-self-centering with a pilot seat.
Series and size
From shaft diameter and required torque / axial force; consider available hub width and diameter.
Hub check
Minimum hub diameter Dmin for the hub material yield strength.
Installation
Tolerances, surface finish, lubrication state and screw tightening torque per the catalogue.
Interchangeability
Locking assemblys are produced in internationally common type and dimension series, so a locking assembly of the same type and size (d x D) from another leading manufacturer is usually dimensionally interchangeable. Mechanical ratings - transmissible torque, axial force, shaft and hub pressures and screw data - can differ between manufacturers. These differences are usually small enough to be neglected, but interchangeability is not automatic: MECHATRIC always checks the mechanical data of the replacement against the duty before confirming it.
Keyless Rigid Shaft Joints & High Bending Moment Connections
Keyless rigid shaft joints and special friction connections - for joining shafts, high bending moments and applications where standard locking assemblies do not fit.
In a conveyor drum pulley the locking device must transmit torque while the shaft bends under belt tension. The bending moment changes the contact pressure and can overload the clamping screws, so it must be included in the selection.
Equivalent Series - Cross-Reference
Use this table to find the equivalent series of another manufacturer. Send the existing part number - MECHATRIC confirms the exact size and rating.
| Type | SIT-LOCK (SIT) | Rexnord Tollok | RINGFEDER | Match |
|---|---|---|---|---|
| Rigid shaft coupling | SIT-LOCK 10 | TLK500 | - | Same dimensions |
Built by MECHATRIC by comparing shaft diameter, outside diameter and ring widths in the current SIT-LOCK (2026), Rexnord Tollok (PT2-001) and RINGFEDER (06.2025) catalogs, checked at d = 50 mm and d = 100 mm. "Same dimensions" = identical d x D and widths; "Close" = same d x D with slightly different widths. Mechanical ratings (torque, axial force, pressures, screws) can differ between manufacturers - usually only slightly - and are always checked against the duty before a replacement is confirmed.
Leading Manufacturers Worldwide
Well-known European, American and Asian (Japanese and Korean) manufacturers of keyless locking assemblies.
| Manufacturer | Country | Product focus |
|---|---|---|
| RINGFEDER | Germany | Locking assemblies, shrink discs, couplings |
| KTR Systems | Germany | ROTEX, BoWex, RADEX-N couplings; CLAMPEX locking devices; brakes |
| BIKON | Germany | Locking assemblies |
| SIT S.p.A. | Italy | Flexible, disc, gear and zero-backlash couplings; pulleys, belts, SIT-LOCK, taper bushes |
| Tollok (Regal Rexnord) | Italy | Locking assemblies and shrink discs |
| Fenner Drives | United Kingdom | Taper-Lock bushes, pulleys, couplings, keyless bushings |
| Tsubaki | Japan | Couplings, POWER-LOCK, backstops, chains |
Listed for market information only. Brand names belong to their owners; their mention does not imply that MECHATRIC represents, distributes for or is authorized by these manufacturers. Product availability and equivalents are confirmed per enquiry.
Need a keyless locking device?
Send the shaft and hub dimensions, hub material, power, speed, torque, axial load and bending moment. MECHATRIC selects the series and size and checks the hub.
Engineering reference: SIT S.p.A. "SIT-LOCK keyless locking devices" catalogue (2026), Rexnord Tollok catalog PT2-001 and RINGFEDER Locking Assemblies Product & Tech Paper (06.2025). Torque, axial force, pressures, tolerances, screw torques and minimum hub diameters must be verified against the manufacturer's current documentation for the selected size. Brand names are used for technical identification and do not by themselves imply representation, authorization or commercial partnership.
Frequently Asked Questions
Self-centering or not self-centering?
Self-centering devices centre the hub on the shaft as they are tightened; non-self-centering devices need a separate centering seat.
Why must molybdenum-disulphide lubricants be avoided?
They lower the friction coefficient and therefore the transmissible torque below the catalogue value.
What limits the selection besides torque?
Hub pressure and minimum hub diameter, axial force, bending moment, tolerances and installation conditions.
Are locking assemblies from different brands interchangeable?
Usually, at the dimensional level: the same type and size (d x D) fits. Mechanical ratings can differ between manufacturers - usually only slightly - so the torque, axial force and pressures of the replacement are always checked against the duty.