Think all jib cranes are the same? As this case study proves, using the right jib crane mounting style can affect your bottom line.
Case Study Overview:
We were recently contacted by a customer planning a new production space. They purchased a 10-Ton freestanding bridge crane system with a 120’ long runway. To expand the workable area, the customer asked for two jib cranes on one side, each 2-Ton capacity with a 15’ span and an electric chain hoist.
Jib Crane Basics:
- Jib crane types include: Floor Supported (AKA base mounted), Wall Mounted (also called Full Cantilever), Ceiling mounted (Articulating), Sleeve Mounted, Tie Rod, and Mast Type.
- Rotational movement can be manual, hand geared, or motor driven.
- Standard catalog jib cranes come in capacities of ½ to 5 Tons and have spans up to 20 feet.
- Outdoor jibs are best supplied with seal welding and a hot dipped galvanized finish, especially for applications in marinas and boatyards.
- Jib cranes have about 15% of the rated load built in to carry the weight of the hoist, and for long-lift hoists, the jib capacity must be upsized to carry the extra weight of this hoist type.
The initial design & calculations:
For this application, the customer’s first choice was the Full Cantilever or Wall Mounted jib crane. This mounting type is bracketed at two points on the jib’s beam, and for their application, the jibs would be bracketed to the same columns supporting one side of the crane system. The customer required 180-degree coverage, and this type of jib crane would work. The crane columns were to be specifically designed to carry both the load of the 10-Ton crane system, and the load imposed by the jib crane.
However, when the loadings were calculated for the Full Cantilever jib, it was shown that the pull at the top hinge and thrust at the bottom hinge were 15,250 lbs. This meant that the column would be pulled at the top with a lateral load of 15,250 lbs, and in the middle, approximately 6’ down, the column would need to resist a thrust load of the same 15, 250 lbs. To accommodate this load, the column itself would have be a far more substantial (and more expensive) piece of steel. We knew there had to be a more cost-effective approach to this problem, and we found it in the Mast type jib crane
About Mast type jib cranes:
Mast type jib cranes are really a hybrid of Floor Mounted and Ceiling Mounted jibs, with connections to both the floor or foundation and the ceiling structure of the facility. This helps to better distribute the thrust and the pull of the load and reduce stress on the overall structure of the facility. While Mast style jibs typically cost more than the Wall mounted style, they can help to reduce costs of the support beams in newly constructed facilities or meet a necessity when existing structures simply can’t support the force required.
By using a Mast Type jib crane, the customer got jib crane coverage along the outside of one runway with significant cost savings on the overall project. While the 10-Ton crane column required a poured, reinforced foundation with imbedded connection bolts, this foundation was simply extended another 18 inches for the Mast type jib. The best part of this design was for the same capacity, span, height under boom, and the same hook coverage, the upper loading on the column was reduced by 75%. While the mast type jib crane cost the customer about 40% more than the full cantilever jib, this extra cost was quickly overshadowed by the cost savings in the design of the steel column.
With nearly 50 years in the business, Shupper-Brickle Equipment offers a sound knowledge of overhead material handling. We provide jibs, gantry cranes, and workstation cranes by Gorbel and Spanco. Contact us for a free assessment to help you find the right equipment for your application.