Jib Crane Glossary

Jib Crane terminology and jargon can be confusing. We want to make the process of buying a jib crane as simple and painless as possible. So please make use of our jib crane glossary to clear up any confusion.




Anchor Bolt Load

The total amount of force that is applied to each supporting anchor bolt; usually measured in kips. The anchor bolt load is important to know when selecting the correct anchor bolts to secure your jib crane.




Axial Load

The total vertical force applied to the supporting structure. Axial Load is relevant for wall mounted jib cranes.

Formula: Axial load = (overall weight of the jib crane) + (design factor x weight of load)




Boom

The horizontal beam (track) upon which the hoist trolley travels. Also know as the “jib” of the jib crane.

Movement along the boom is called the "traverse motion" and is the movement in and out from the hub of the jib crane.




Bracket Center (Fitting Center)

The distance, center line to center line, between two supporting brackets (fittings) of a wall mounted jib crane (i.e. the distance between the two wall mounting points).




Capacity

The maximum live weight that the crane is designed to support. For most jib cranes, the design load is based on the capacity, plus a hoist & trolley allowance (15% of capacity) and an impact allowance (25% of capacity).

The allowable deflection of the crane is calculated using the design load plus the hoist allowance. Load testing can be performed to 125% of rated load capacity.




End Stops

Typically an angled piece of steel bolted or welded to each end of the boom to prevent the trolley from falling off of the beam or hitting the hub.

End stops restrict the range of the traversing motion of the jib crane.




Deflection

The difference in elevation at the tip of the boom between an unloaded crane and a fully loaded crane; usually measured in inches.




Foundation (Footing)

Free Standing jib cranes require that a special foundation, usually of concrete and steel, be used to support the crane and prevent the crane from tipping over.

Foundation recommendations can be found in the price pages and in the installation manual.




Gussets

Reinforcing plates used to stiffen the mast at the base plate of a jib.




Head

Houses the roller, and lowers the crushing forces that are imposed on the mast. The boom is mounted to the head of a jib crane.




Hoist

A mechanical unit that is used for lifting and lowering a load via a hook or lifting attachment. Hoists are typically either powered either manually(by hand) or with electricity or air power.

Electric chain hoists are the most common type of hoist used for jib cranes. Manual hand chain hoists are used for light duty periodic applications. Electric Wire rope hoists are used for higher capacity larger jib cranes typically over 5 tons.




Height Under Boom (HUB)

The distance from the floor to the underside of a jib crane's boom.

The minimum height under boom equals the height of the load, plus the maximum distance the load is to be lifted, plus the headroom required for the hoist, trolley, and attachments.




Mast

The vertical steel component of a jib crane which supports the crane.

Free Standing jib cranes (including Work Station Jibs) have a circular pipe for a mast, Wall Cantilever cranes have standard I-beams, and Mast Type cranes have wide flange beams. Wall Bracket cranes do not have a mast.




Overall Height

The distance to the highest point on the jib crane (should include hardware).

A minimal clearance (nominally 3 inches) is required from any obstructions above the boom or tie rod assembly throughout the entire rotation of the crane.




Overturning Moment

the overturning moment is the force applied to the mounting structure of a free standing jib crane.

This load is created by suspending a load from the boom, and is greatest when fully loaded, at the very end of the boom.




Rotation Stops

Limit the rotation of a free standing or pillar base mounted jib crane boom (which are normally 360°).

Rotation stops are an optional accessory that are field welded to the mast.




Span

For a jib crane, span is the distance from the center of the pivot point to the end of the boom.

Note that "span" is greater than actual “working span” or “hook coverage.”




Supporting Structure

For a free standing jib crane the supporting structure is the foundation which the crane is bolted to or implanted in.

For a wall bracket or wall cantilever jib crane, the supporting structure is the wall or column to which the crane is bolted.

Mast type jib cranes have a supporting structure at both the ceiling and the floor.




Thrust & Pull

Forces exerted by a crane on its supporting structure. Thrust is the pushing (or compressive) force exerted on the structure, while Pull is the tensile force.

Thrust and Pull are thus equal (but opposite in direction) to each other.

The maximum thrust & pull occurs when the crane is loaded at full capacity, with the load at the end of the boom




Trolley

The mechanism that carries the hoist along the boom navigating the span.

Trolleys are a separate component not included with most jib cranes.

Workstation cranes with enclosed track designs typically do include a trolley for hook mounting a hoist.




Working Span

The working span (or hook coverage) is less than the span of the crane. It is a function of the maximum hook reach and the ability to get the trolley close to the mast.

Working span = (distance between trolley stops) - (hoist trolley length)