FAQ – Frequently Asked Questions
SIT-LOCK® Locking Devices Line
Frictional locking devices from the SIT-LOCK® LINE create pressure between the shaft and the coupled part simply by tightening the screws. This pressure develops over the entire contact surface of both the shaft and hub, enabling quick and safe locking of the clamped parts.
Where I find the data for correct locking device sizing?
All data, transmissible torque, permissible axial force, etc., is available in our catalogue which can be downloaded from our website(Link DOWNLOAD PDF Catalogue). No additional calculations are needed.
What are the installation and removal requirements?
For installation, you just need to tighten the screws to the value indicated in the catalogue table, and for removal, you just need to evenly loosen the screws. There are even disassembly threads that allow the clamped parts to be unlocked even in extreme conditions. So installation and removal are both quick and easy.
Are shaft and hub tolerances and surface finish required?
Tight tolerances are not necessary. h8/H8 tolerances are typically used. Some products may allow for h11/H11 tolerances. All the information is available in the catalogue.
What are the standard operating temperatures?
The values shown in the tables are valid for temperatures from -20 °C to +200 °C. For uses lower or higher than these values, please contact our Technical Department.
Are applications that combine simultaneous loads possible?
SIT-LOCK® locking devices can address applications that simultaneously present torque, axial force, bending moment and radial force. For further information, contact our Technical Department.
Why does the shaft resistance distribution increase?
The shaft has no slots and the pressure generated by tightening the screws does not cause any reduction of the shaft’s resistance distribution. This allows for a reduced shaft diameter while applying the same stresses, leading to considerable savings on costs.
How is the axial and angular adjustment carried out for SIT-LOCK® locking devices?
Unlike conventional couplings, SIT-LOCK® locking devices simply require placing the hub in the desired position relative to the shaft, and tightening the screws.
Are the contact parts prone to oxidation?
Even in damp environments, the pressures created along the contact surfaces do not allow for oxidation, ensuring easy removal of the locked parts.
What is meant by “no play”?
Locking machine parts with SIT-LOCK® locking devices guarantees a perfectly rigid coupling with zero backlash, providing precision to the shaft-hub coupling.
Are they recommended for applications subject to continuous alternating loads?
By using SIT-LOCK® locking devices, the stresses generated by alternating or sudden loads are distributed over the entire surface of the shaft and not over a reduced section as occurs with traditional systems.
Which parts can SIT-LOCK® locking devices connect?
With the SIT-LOCK® line, any hub part can be fixed (flywheels, pulleys, chain wheels, gears, levers, joints etc.)
How many different solutions are in stock?
SIT Spa, a friction clamp manufacturer operating for over 30 years, keeps various types of locking devices in stock to cover a wide range of applications.
Where can I download CAD drawings?
SIT Spa provides a free tool for accessing documents and downloading the standard components catalogue, which includes the line of SIT-LOCK® locking devices. (Link: DOWNLOAD cad SIT-LOCK® line)