What slew bolts?
Slewing ring bearing bolts have a direct effect on bearing life, put simply if the bolt tension is incorrect or relaxes the bearing wear rate increases. We first became involved with these in 1995 on North Sea Offshore cranes.
What is rocking test of crane?
The rocking test comprises the measurement of the deflection between the crane pedestal and the rotating crane housing in the way of the slewing ring using a dial test indicator to determine the bearing clearances.
What is the purpose of crane rocking test?
– Rocking test of deck crane is carried out to ascertain the wear down of the sleeve bearing of the deck cranes by measuring the play (relative movement) between the inner and outer bearing race. This measurement indicates the rate of wear.
How does a slew ring work?
The purpose of slewing rings is to enable rotational motion between different components in a system (Ritbearing). That motion can be radial, axial or tilting. Slewing rings can be made of a variety of rigid materials such as carbon steel, chrome steel, stainless steel, brass, plastic and/or anodized aluminum.
What is the purpose of a slewing bearing?
Slewing bearings comprise an inner ring and an outer ring, one of which usually incorporates a gear. Together with attachment holes in both rings, they enable an optimized power transmission with a simple and quick connection between adjacent machine components.
How do you measure a crane rocking test?
– Usual rocking test reference points usually two of them on the front and rear bottom plate of the crane….– Measurements are typically taken in four positions on the slew bearing, with the jib pointing:
- Extended towards forward.
- Extended Towards aft.
- Hard to port side.
- Hard to starboard.
How do slew drives work?
In operation, the slew drive’s axial movement, or motion around its axis, interacts to create radial torque. The action occurs by meshing the grooves of the horizontal screw with the teeth of a perpendicular gear. While turning, the worm gear’s axial movement transfers magnified torque force to the radial gear.
What are slew drives used for?
A slew drive is a type of gearbox that is specifically designed to handle high radial, axial, and moment loads. They are designed to withstand hold loads while also providing high rotational output torque.
How do slew rings work?
What is a slew ring on a crane?
A crane may have multiple vital components for its operation, but a slew ring is the most critical component in designing a crane load chart. Overall, the slew ring will reflect how much load a crane can lift, and the allowed distance where this load can be lifted at safe operating conditions.
What is crane slewing bearing?
Crane slewing bearing is one of the most important components for cranes. Cranes are lifting machines that use levers and pulleys to lift very big weights.
What are the characteristics of a crane?
Cranes are lifting machines that use levers and pulleys to lift very big weights. And the astonishing thing is that these machines are not an invention from the modern industry but have a long history of more than 2000 years. There are many different types of cranes.
What are high tensile bolts used for?
This is a summary of that guidance. High tensile bolt connections are used on tower crane joints, including those on mast, jib and slew ring bearings. They are subject to repeated cyclic loading as the crane lifts and lowers, loads and slews.