Home>Topics>>Trailer Components and Systems

Trailer Components and Systems

Fri, 15 Jul 2011|

Steve White reviews trailer components and systems, focusing on points that can be used to stabilize these vehicles in the event of an accident.

+

Transcript

[MUSIC] Welcome to Training Minutes my name is Steve White, and i'm the [UNKNOWN] chief with the Fishers Fire Department. In this segment we are going to go over trailer components and systems. We are going to start here at the nose of the trailer and these are where our glad hand connections are to run from the cab for the service and our parking breaks. Also we have our 12 volt connection that runs electrical power from the cab to the trailer. From there, we're gonna look at the kingpin. The kingpin is where the trailer connects into the cab at the fifth wheel. Behind the kingpin is a big, steel plate that runs about four foot back and is the width of the trailer. This could be a good place to stabilize the trailer. These are the dollies. They're located on every trailer of a semi. They crank up and down in place. This can become an advantage for us because the dollies are not damaged in the accident, we can lower the dollies down and help stabilize the trailer. Above the dollies, let's take a look at the floor construction. The floor of the trailer is the most stable part of the trailer. The floor joys run anywhere from 10 to 18 inches on center. And when we stabilize building a box script from the ground up to the under side of the trailer, this is exactly where we want to capture our points of contact. You can read it from the outside by the rivets on what's know as "the rail." On the underside of some trailers, there will be a bracket in place to hold simply a spare tire. One thing that we want to point out is: that is not acceptable spot to put cribbing. Anytime that we crib, we want to crib up to the floor joists. Before we go into the trailer, let's take a look at what we're gonna call the bumper. It's known by other names such as a DOT bar or ICC bar, we're just gonna call it the bumper. On size up, evaluate it, if it's not been damaged, it can be used in stabilization. Keep your stabilization in line so we can transfer the load down to the ground. And if you're not sure, go into the frame rails just inside and stabilize to each of the two frame rails. We're sitting here in the back of the van trailer with the doors open and we wanna talk about some of the construction features. The floor is gonna always be the strongest part because that's where we're putting all our weight. The side walls, the roof. Are very thin. They're designed to just protect the load from the elements, nothing more. Anytime the load is wrecked in an accident, it'll easily lean in and bow out the wall. And a lot of times it'll even puncture, and go out and make the trailer completely weak. Just like any other approach on an accident, we use our Hazmat skills, look at placards, look at markings, speak to the driver if he's not incapacitated. We wanna find out what they're hauling. Typically, there's not any urgency for us to open the doors because when we open the doors, whether they're swing-out doors or roll-up doors, we have to consider that the load may have shifted and can actually come down on our personnel. So try to avoid opening your doors at any cost during a trailer accident. The previous trailer we looked at was what we commonly referred to as a van trailer or box trailer. This trailer is what we call a refer. Short for refrigeration. Notice the refrigeration unite right here at the top at the nose of the trailer. Typically we'll keep this running when it's been involved in an accident so that we can save the perishable goods in the trailer. However if we think it's gonna cause a hazard, because it is a combustion engine, we will have to shut it down. The controls are typically here on the driver side and they're easily labeled on and off. Another important feature with the refer trailer is the fuel cell. The fuel that runs the refrigeration unit is not supplied by the cab it's supplied by the trailer. This becomes a critical factor if it's been involved in an accident. So we'll have to follow our normal hazmat mitigation procedures. If it's been compromised. Another key point is, we don't want to stabilize this, this is not a point for stabilization. Again we want to go through the floor joist to ensure good positive contact to stabilize the trailer. This is a low boy detachable trailer. Basically it's used to haul heavy equipment. And rather than have that heavy equipment drive off of the back of the flatbed, it'll simply drive off the front once the cab pulls away after it's detached. Between the two, what we have are our glad hands, for our emergency, or parking, and our service brakes. One thing to remember is that once we disconnect these from any trailer that we completely lock the brakes to the trailer. Then we have our 12-volt connection. This line happens to be green, which typically indicates that the trailer has antilock brakes. and then because we have hydraulics involved, we have two hydraulic connections, and they operate just like hydraulic tools, there's an in and an out of return, and you simply slide it back and disconnect, and that's how we can tale power, air, and hydraulics separate from the cab and the trailer. Another unique feature about the detachable low-board trailer is that it has a secondary set of air and power connections that have to be disconnected. And that removes power. From this section of the trailer to the backend of the trailer, and again ensures that we've locked the air brakes. On this cab that's hauling a lowboy detachable trailer, you can see on size of the larger tank is for diesel. The smaller tank. If for hydraulic oil and you can tell because it's got pressure relief and you can actually track the lines that go to powering the hydraulics. The next trailer we're going to take a look at is the dump trailer. There's two types of dump trailers. There's a frame and frameless. This is a frame dump trailer. You'll notice. And it's got a hydraulic line that attaches to the cab that tows it. So it can operate a hydraulic piston that'll lift the trailer, causing it to dump. Typically, we have stone, gravel, sand, sludge and various types of material that will have to be dumped at its location. At the back of the dump bed, we have the gate. The gate can either swing to the side, or swing up. It's important for us on size up, that if we have a vehicle that's come in contact with the back, we want to evaluate the stability gate, to ensure during rescue operations, the gate doesn't open, spilling it's contents onto the action area. Simply using chains, and a combination of come alongs, we can secure the gate in a secured position, and make sure that it's not gonna open uncontrolled. Keep in mind there are many different types of trailers that run up and down our roads every day. In this segment we were able to show just a few basic, common types that we see in our jurisdictions. Thank you for watching this segment of Training Minutes, and thank you to Holmatro for sponsoring it.

Related Videos:

  1. Stabilizing Heavy Trucks

    Steve White explains why firefighters can't take a small vehicle approach to large vehicle stabilization and examines common cribbing and methods of stabilization . Sponsored by Holmatro.

  2. Vehicle on Its Side

    Dave Dalrymple describes how to stabilize and rescue a patient from a vehicle that has fallen on its side. Sponsored by Holmatro.