FREQUENTLY ASKED QUESTIONS

The vertical column of a floor mounted crane should be fairly plumb. These cranes rotate very easily. With a load on the boom, if the column is not plumb, the boom may rotate by itself. In order to prevent unwanted boom rotation, it is certainly beneficial to spend extra time insuring the column of a floor mounted jib crane is plumb.

Most installers will finish the concrete very flat and then bolt the jib crane column directly to the foundation. Our jib columns generally are very square because they are welded on a rotating semi-robotic jig. However, no weldment is perfect. The use of a mortar bed to correct any imperfections in the finish of the foundation or to plumb the jib crane column is perfectly acceptable.

Floor mounted jibs require a concrete foundation with reinforcing steel rods and anchor bolts embedded in the concrete. The wall-mounted jibs require mounting bolts (12). These bolts, supplied by others, must be no less than Grade 5 quality. The size is specified on the approval drawing, and ranges from ½” diameter to ¾” diameter. Usually a minimum of a man-lift and a forklift truck are required to install the cranes. Large cranes may need additional equipment for installation.

1″ Mild steel anchor bolts/nuts or GR2: 200 ft-lbs. max
3/4″ Mild Steel anchor bolts/nuts or GR2: 150 ft-lbs. max
3/8″ Grade 5 bolts/nuts: 20 ft-lbs.
1/2″ Grade 5 bolts/nuts 50 ft-lbs.
5/8″ Grade 5 bolts/nuts 100 ft-lbs.
3/4″ Grade 5 bolts/nuts 175 ft-lbs.
1″ Grade 5 bolts/nuts 200 ft-lbs.

Most jibs are shipped loose with the hardware in a separate box, in a closed trailer by common carrier. Some of the larger cranes require a flat-bed truck or trailer. The bridge cranes are commonly shipped on a flat-bed trailer. Other methods are available. Units may be palletized which may better protect the finish for an additional cost.

Yes. Contact us with specifications and we will let you know if we can meet them.

Yes. Both wall mounted and floor mounted jib cranes can be fitted for motorized rotation.

The typical voltage for large motors used in lifting devices is three phase and usually 230 or 460 volts. (230-3-60, or 460-3-60).

Yes. Please contact us for details and pricing.

Our standard jib cranes are designed for indoor use. We can provide special shielding on the jib for outdoor use. Special maintenance will be required for jibs used outdoors. Please contact us for details and pricing.

Where Applicable:

Occupational Safety and Health administration, General Industry standards
American Institute of Steel Construction
Crane Manufacturers Association of America, Specifications no. 70 & 74
American Society of Mechanical Engineers/American National Standard ANSI B30
National Electric Code ANSI/NFPA 70
American Welding Society AWS-D14.1 & D1.1

A jib’s life expectancy depends on the environment, the severity and frequency of use , the ambient temperature, and other factors. For this reason, we cannot provide a value for life expectancy. Contrx brand cranes are designed for daily use, and with the exception of routine maintenance, should provide years of trouble free operation.

Most of our standard jib cranes have a 2-week lead-time. Other time requirements apply to special or modified cranes and our large jib cranes. Please contact us for lead times on specific products.

The rated capacity of the jib is the maximum “live load” the jib can pick up. A typical hoist and trolley weight is assumed and added to the rated capacity for design purposes. These assumed weights are 15% of the rated capacity and are not considered part of the “live load”. However, hoist and trolley weights greater than 15% of the rated capacity should be considered part of the “live load”

Contrx Industries manufactures its floor and wall mount jib cranes according to the design specifications and standards of the American Institute of Steel Construction and the Occupational Safety and Health Administration, as applicable.

Cumulative boom deflection, or the distance toward ground that a fully loaded jib crane boom will displace, is a function not only of the boom beam size and moment of inertia, but also of the total column deflection, flexure in the base plate, distortion of the upper head assembly, and the method of anchoring.

In order to accurately predict the amount of deflection possible in our product models, we randomly erect and test production units. Our empirical tests, coupled with static analyses of the units, indicate the following:

– For floor mount jib cranes with boom lengths of 10 feet or less, a cumulative deflection in the range of 3/4 to 2-1/4 inches can be expected.
– For floor mount jib cranes with boom lengths of 11 to 20 feet, a cumulative deflection in the range of 1-1/2 to 4 inches can be expected.