Installation Guide - MAV Keyless Locking Device
Author - Steve Hittmann Power Transmission Product Manager
Why use a
Keyless Locking Device?
keyless locking device, also known as frictional locking assemblies, provide a
keyless, zero backlash connection between a shaft and hub in applications like
gears, conveyor pulleys, vee & synchronous pulleys, sprockets, cams,
levers, rotors, and many others. This locking method eliminates the need for
keyways and the associated problems with keyway mounted applications.
are well suited to transmit torque, thrust loads, bending moments, and radial
loads both separately and simultaneously. When considering a selection, the
catalogue ratings do not consider any safety/service factor, and additional information
is available from your local CBC branch or representative.
of keyless locking device is known in the market via a wide variety of
descriptions including shaft locking device, friction lock, keyless friction
locking device, shaft locking assembly, locking device, and Ringfeder.
of Friction Locking Devices and their Design
Keyless Locking Devices meet or exceeds the advantages of the traditional
interference fit, press fit or shrink fit, yet is simplified for ease of installation
and removal. It is based on the wedge principal. The axial load on the screws
generates a high radial load through the tapers to the hub and the shaft that
locks the components by using friction.
important to note that new designs have been developed for today’s market that
offers advantages over the classic or initial versions of this type of locking
device. The classic, or first style, relies on the fasteners to hold the radial
load, as they have steep tapers within their design. The later designs offer
shallow tapers, which are self locking and only use the fasteners for the
initial installation. Once the installation is complete, the fasteners do not
carry any load.
Features of the MAV Keyless Locking Device
- Mounting and positioning is easy via a slide in/on fit
due to the generous tolerances when the unit is in its free state. Shaft and
Hub tolerances are sufficient for easy mounting and correct positioning.
- High manufacturing precision results in close geometrical tolerances, leading to a well balanced connection, even in high speed applications.
- The high pressures produced by the MAV allow for high torques to be transmitted. This type of locking has the additional advantages of assisting with bending moments with alternative designs either improving rigidity, i.e. MAV 2005, or providing shaft flexibility, i.e. MAV 1061. Eliminating fretting corrosion is an additional benefit.
- With the absence of notches, found in traditional shaft connections, like taper lock bushes, keyed shaft connections, and splines, this type of locking device enhances static and dynamic strength, leading to lighter and more cost effective designs.
- The large variation of design types available within the standard catalogue coupled with the possibility of designing and manufacturing customised units with short lead times, allow CBC and our customers to find the best solution for a wide variety of applications.
supply MAV keyless locking devices ready for installation. Catalogue specifications
are based on a friction coefficient of (u=0.12), for lightly oiled rings,
screws, shaft, and hub bore.
Please note: DO NOT USE molybdenum disulphide
lubricants like; Molykote, NeverSeez, Anti-Seez or similar.
- Disengage the rings by loosening the screws or by
tightening some screws into the push-off threads.
- Insert the locking assembly into the application to be mounted and relocate any screws used to separate the unit.
- Ensure you have checked that your shaft and housing bore conform to the catalogue specified tolerances. Check with your local CBC Office or Representative.
- Ensure the correct position of the shaft and hub, and then tighten the screws by hand.
- Using a torque wrench set it approximately 5% higher than the specified tightening torque. This will be found in the box the MAV was supplied in, or you can check with your local CBC Office or Representative. Ensure you tighten the screws in a cross pattern in several steps, e.g. 12:00, 6:00, 9:00, 3:00, etc.
- As a final check, reset the torque wrench to the specified tightening torque and make sure no screw can turn at the specified torque, otherwise repeat the procedure from step 5.
initiating the removal procedure, check to ensure no load is acting on the keyless
locking device, shaft, hub or any mounted component.
all screws. Transfer required number of screws into all push-off threads.
- Tighten the screws in a cross pattern in several steps (e.g. 12:00, 6:00, 9:00, 3:00, etc) until the rings disengage
Detailed installation & removal instructions for each specific series is
also available from your local CBC Office.
For a demonstration video on installation
and removal of a keyless Locking Device Click Here.
supplied this locking method for original equipment applications as well as
upgrading old designs when problem solving. Issues such as keyway wear, within
indexing (forward-reverse) applications, or difficulty when removing or
installing press fit hubs, such as couplings, sprockets, pulleys, gears, and
levers can often be completely eliminated. This can result in an ongoing
maintenance saving. The capacity of a standard press or interference fit can be
substantially increased when implementing this locking method.
of this type of keyless locking device assemblies available from CBC include,
MAV, TAS, Tollok, TLK, Trantorque, Ringfeder, Compomac, Conex, Euroconic,
Bikon, Peter, Ringblock, Clampex, Power-Lock, Shrink Disc, ConLoc, SIT,
HiPerDrive, Powertech, Stuwe, Fenlok, and Super-Lock.
information is available at the CBC Design Centre, Click Below.