Jaw Coupling Hubs

How to install a jaw coupling hub?

• The customers should first buy a spider according to the selected hub (preferably from the same corresponding series) having the same specifications & parameters.
• After purchase, they should ensure that each component is free from contaminants, defects or cracks and match the shaft diameter to the bore size of the hubs.
• Before starting the coupling installation, users should ensure that the machinery is disconnected from all power sources. They should also not install it on unstable or moving equipment.
• The hubs having key slots should be fitted with the keys and slid fit into shafts for preventing slipping during shaft rotation. The keyless hubs can be attached directly to shafts using set screws.
• The users should insert a spider into a hub while ensuring that the spider opening is large enough to fit both the shaft & the optional key. Selected jaw coupling hubs can be overhung slightly or be moved back on the shafts for adjusting according to misalignments in shaft separation.
• Then, the second hub is brought near the first hub while keeping the guidelines in mind, such as the gap between hub faces.
• Users should check the set screw tightness & alignment before testing to prevent possible misalignment.
• Now the coupling is ready for operation, users should remove any material or tool away from the shaft and coupler. The equipment is ready to start up and test.

What is the difference between rigid and flexible jaw coupling?

Rigid couplings offer a rigid connection between two shafts that are firmly connected. They transfer torque smoothly throughout the system. These rigid couplings can't handle misalignment and shocks. Flexible couplings like jaw coupling hubs provide flexible connections and hence, can withstand shocks & misalignment up to a certain extent. However, there is a chance of some losses during torque transfer while using flexible jaw coupling.

What are some common mistakes the users make while selecting a jaw coupling hub?

• Failing to check maximum bore capacity: Users should always check the shaft size of the driving equipment before purchasing a jaw coupling.
• Using same size couplings everywhere: Using the one-size-fits-all approach may seem like a good idea to prevent downtime. But an oversized or undersized jaw coupling may cause malfunctioning in motors and failed couplings.
• Ignoring heat and chemical compatibility: Since the jaw couplings require purchasing of both hubs and spiders, the customers should take note that both the coupling hub & spider materials are compatible with the required environments.
• Overlooking space restrictions: Users should make sure that the selected couplings according to required torque applications can fit the provided space. High torque applications require either a large diameter coupling to handle high torque or coupling with different designs & high torque density.

How to choose the right jaw coupling hub?

• Determining the usage.
• Choosing the material considering the intended application environment.
• Selecting the coupling on the basis of torque, speed, bore size and other factors.
• Jaw coupling hub types are based on usage and their ability to handle the degree of movement or rotation. For example, curved jaw coupling hubs (Lovejoy CJ Series) transfer high torque and can handle some degree of rotation (backlash) due to their curved jaw design.

What is the difference between keyway and keyless jaw coupling hubs?

Selected models of jaw coupling hubs feature a cutout slot in the mating part (hub) of the couplings, known as keyways. These slots or keyways fit in the keys or a separate mechanical attachment on the shafts or other mated tools. The use of "Keys" leads to improved torque & prevents slipping. It also results in reduced losses due to vibrations & backlash (degree of free movement between two rotating, mating parts).
However, some applications do not require keys, as keyless jaw coupling hubs use only set screw holding power to transfer torque. Keyless hubs are ideal for applications that cause no damages or injuries even if the shafts slip. Keyed jaw coupling hubs concentrate the stresses around the key or key slot, causing maintenance issues and efficiency losses. Keyless hubs distribute the load & hence require less maintenance.