Is your crane running straight? If it is not what are the consequences? Many people don’t realize the damage abnormal tracking can cause to your crane and your runway. Bad tracking can result in premature wear of your bridge crane wheels, bearings, runway rail, and cause crane binding or racking, bridge drive breakage, or even causing broken couplings, gearing, and axles. I have seen time and time again where people will just fix these broken components instead of trying to find the cause of the breakage or excessive wear. People will change a bridge wheel and bearings just to find in a year or two later they have to invest in yet again another set of wheels and bearings. If you’re having excessive wear on your wheels or rail, or you are finding yourself replacing bridge couplings, and axles then this could be caused by abnormal tracking. There are several causes of abnormal tracking and finding these issues is becoming easier with new technology.
Crane Rail Alignment Requirements
In order to have correct tracking the runway and bridge system has to be within CMAA Spec 70 tolerances which requires the system to be square. The runway rail must be straight and parallel, and they must also be the same elevation the entire length of the runway. Depending on the span of the bridge the allowable tolerances will change.
- The distance center to center of rails must be within +- 1/8”
- The level of the runway rails should be within +- 1/8” of each other at all opposite points
- The elevation of each rail along its length must be level within +- 1/8”
During the data collecting many crane companies fail to check the elevation of the runway and concentrate on the rail span. Although the rail span is vital for proper tracking elevation is just as important. Elevation problems can cause your tracking to be off center. One possible identifier in elevation issues is when one endtruck is centered straight on the rail and the opposite end truck is off center and against the wheel flange. If your elevation is off you will see premature wheel flange wear, and rail wear.
Other Crane Tracking Issues
Just because you are having what appears to be tracking issues it is important to rule out certain crane problems prior to analyzing your runway. This could save you a whole lot of time and money if these issues are checked first. There are several crane issues that could cause abnormal tracking that is unrelated to your runway or bridge squareness including the following which should be verified before performing major runway alignment or repair.
- Different diameter bridge wheels
- Bent end trucks
- Bridge brakes not releasing simultaneously
- Bad bridge bearings
- Bad bridge couplings
- Different RPMs on drive wheels
- Different torque values on drive motors
- Out of square bridge wheels
Crane Damage From Poor Alignment
Once these have been verified to not be the issue then we can focus on the runway. If the runway is the issue it is vital to correct the issue as soon as possible. Delaying repair can result in extensive crane issues that will not go away by just replacing the broken component. Your investment will be wasted in useless repairs that will only keep your crane running for a short period. Without the corrective action you will be causing your crane…
- Wheel Flange Wear
- Railhead Wear
- Bearing Damage
- Coupling Damage
- Axle Damage
- Gearing Damage
- Crane Racking and binding
10 Questions to Ask Your Crane Service Provider
There are several ways to fix runways that are out of alignment. However, to do the repair properly you really need to know exactly where the problem is and to what extent of repair is required. The solution of a cost effective repair is only going to be viable if you have an accurate reading of the dimensions of the entire length of runway including the runway area where no repair is required. This enables you to find the best solution for the runway repairs. This typically is a large investment so you want to make sure you have the right vendor finding out exactly where the runway and rail is off and how to correct it. When deciding on a vendor for your crane runway analysis you want to ask the following ten questions…
- How will you be data collecting?
- How accurate is your data collecting?
- How long will my crane be down during the data collection?
- What qualifies your team to collect the runway data?
- How will I get my results?
- Will I get any kind of report?
- Who analyzes the data?
- How do you decide what needs repair once the analysis is completed?
- How long does this process take?
- How will you get to all the runway areas to take accurate measurements?
Once you have asked these questions and have asked more than one vendor, compare them and pick the one you are most comfortable with. Be sure one of the vendors you call is Konecranes. Konecranes has a state of the art runway survey called RailQ. This survey is the most accurate I have ever seen on the market. A robot called Roborail travels the length of your runway collecting data of the span and elevation throughout the length of the runway rail. It is a very fast way to collect all the required data reducing your downtime and no personnel has to walk the rail making it very safe to perform. The data is analyzed by engineers and the reports are in 3D giving you an easy understanding of your runway issues. The additional benefit is that this program will find the best solution to fix the runway reducing your overall repair cost. Find a nearest Konecranes and check out the newest technology on the market.