What is an Overhead Crane? | Cranes 101
I’m going to teach you everything you could possibly need to know about Overhead Cranes. Welcome, to Cranes 101. I’m Chris Whitney, with Progressive Crane. With over 40 years of Overhead Crane manufacturing and engineering We’ve come into contact with all different sorts of manufacturers that use Overhead Cranes. Some know cranes better than I do. Some have no experience what-so-ever. We’ve come across people that need a little more hand holding and help filling in the blanks. That’s where I come in. Starting with, “What is an overhead crane?” And drilling down to some of the codes and regulations Our goal is to help you establish a base level knowledge of overhead cranes So we can help you pick the best overhead crane for your application. You ready? Let’s Get Started! Basically, an overhead crane is a machine That allows you to lift a piece of material And move it from one location, to another location, Using precise motion. You’ve actually been around cranes your entire life. Look familiar? That’s all an overhead crane is. Aside of making your life easier. Overhead cranes are used for two main purposes. Efficiency and Safety. An overhead crane can work up to three times more efficiently Than a group of workers or two tow motors. They can also be used in extreme environments to prevent bodily injury to the operator. Sure they look cool! But overhead cranes can be used to raise the level of safety as well as productivity. So now you know roughly what a crane is. Let’s identify some of the components. Let’s start with the most basic component. The Hook. The hook is used for attaching your load to the crane so it can be raised and moved. The Hoist, is what moves the hook up and down. That is mounted to the bottom of your bridge. What moves your hoist from side to side across the bridge is your trolley. Your bridge, is your loadbearing beam that the trolley rides on. That can be Toprunning or Underrunning configuration. Your runway beam is what allows your bridge to travel from one end to the other. End trucks are what physically drive your bridge down the runway. Think of a car. They have wheels and motors that drive them. The control panel mounted to your bridge crane.That’s what sends the signal to your end trucks. That tell it to move through a push button or a radio controller that the operator is holding on the floor. or in the CAT. There are two types of Electrification systems you’ll see with a crane. First, you have your runway electrification. Which is what brings power from the building, to the crane. And then, across the bridge you have a festoon system or conductor bar system That brings power and control to the hoist trolley. Before we review the different types of cranes, if some of these terms are new to you. It would be a good time to go back and look through what we provided. Our goal is to teach you. And repetition usually works best. Overhead cranes come in all shapes, sizes, and capacities. A few things to consider when sizing an overhead crane. What’s the weight you are lifting. What’s the size of your building? Is it a new building and is it adjustable? You’ll want to look at the span of your crane. What is the length of your runway? Is it going to be indoors or outdoors? How many times, per hour, are you going to be performing a lift. And what percentage of that capacity are you going to be lifting? Once you figure out what you need, it will help narrow down your search. I’m going to break down the different types of overhead cranes. And we’re going to start with the most complex one. The bridge crane. A bridge crane system includes two overhead runways and a bridge that rides on it. It also includes the hoist and trolley that rides side-to-side. And can be in a single or double girder configuration. So what does all this “Single”and “double girder” nonsense? A single girder crane consists of a single beam that rides above or below the end trucks, based on whether it is a toprunning or underurnning configuration. Typically, this type of crane is less expensive due to: lower freight cost, simpler installation A simpler hoist trolley design, as well as it allows for lighter runway beams. A double-girder crane design consists of two bridge beams. And again can be top-running or under-running. This type of crane is a little more expensive than a single girder. And that’s typically due to: the freight being a little bit more for shipping, two bridge beams, Also, takes a little bit longer to install has a more complex hoist and trolley design And also will typically require a heavier-duty runway beam. Bridge cranes fall into two categories. You have Process Cranes and you have Modular cranes. A process crane is build for specific needs. Typically, on continuous operation, in a Steel Mill, Auto industry, or container yard. CMAA classifies these as D. E. or F duty Cycle Cranes. Basically, that means that this crane is being used for 10 to 20, or even more lifts per hour. at 50 to 75 percent of the rated capacity. Modular cranes are usually found in smaller industry applications. Typically, you’ll see these in a machine shop or a smaller mill. They’re more economical and affordable, CMAA typically classifies these cranes as a C or below. But, with a little extra engineering, can also be a Class D application. Typically with these units, your lifting 40% of the rated capacity. For five to ten lifts per hour at most. So a bridge crane doesn’t sound right to you? Lucky for you, we’ve got other options. A gantry crane is like a bridge crane. Only instead of being suspended in the air, has legs That ride on an embedded rail on the floor, or can also ride on the concrete. Gantry Cranes are versatile. You can use them in outdoor settings, in rail yards and ship yards with a high duty cycle. When rails and columns cannot be used. Or, you’ll see them inside when an overhead obstruction limits you from using a bridge crane. Monorail cranes are used in production on Assembly Lines where work is moved from one work station to another. Without having any side motion. Like a single girder bridge, the trolley rides on the underside of the beam. and allows you to transfer your loads. In addition, you can also use a track switch which will allow you to go from one monorail to another. or transfer a load from one rail to another. Jib cranes come in a number of different configurations And are typically used when an overhead rail system is not available for a crane. They come in a number of different capacities, spans, and sizes. Depending on your need. They can be wall mounted or they can be floor mounted. And typically give you 180 degrees to 360 degrees of travel. A workstation crane is used for an individual user. they can range from capacities 250 pounds to two tons. And can be free standing or ceiling hung depending on the space that you have. The key here, is, the ergonomic use and versatility. So that’s it. I know it was a lot of information but this was supposed to be a crash course into everything that is overhead cranes. As we move further into the cranes 101 series, we’ll take a deeper dive into each type of crane and find out what makes them tick. Progressive Crane is the leading manufacturer in the overhead crane industry. We engineer and build customer solutions using all the cranes we just discussed. Our work is done in full compliance with CMAA, ASME, OSHA, and NEC codes. We also have AWS certified welders on staff. For applications a little more complex, we also have an Engineering staff that can provide a professional engineered stamped drawing. In addition to that, we can also design custom below the hook, lifting solutions to suit your needs. If you’re interested in learning more about how overhead cranes, can improve efficiency and safety in your plant. Or, you would like to schedule a crane consultation, please contact us and we will set you up a crane specialist. For all of us at Progressive Crane, I’m Chris Whitney. Thank you for watching Cranes 101.