The intention of a trailer coupler is to secure the trailer to the towing vehicle. It is an important piece, as the trailer couple attaches to the trailer ball. This then forms a ball and socket connection.It allows for relative movement between the towing vehicle and trailer while towing over uneven road surfaces. The trailer ball shouldbe mountedto the rear bumper or to a drawbar, which may be removable. The drawbar secures to the trailer hitch by inserting it into the hitch receiver and pinning it.
The three most common types of couplers used are straight couplers, A-frame couplers, and adjustable couplers.Another option is bumper-pull hitches in which case draw bars can exert a large amount of leverage on the tow vehicle.This makes it harder to recover from a swerving situation (thus it may not be the safest choice depending on your trip).
A trailer is not very difficult to categorize. In general, it is an unpowered vehicle towed by a powered vehicle. Trailers are most commonly used for the transport of goods and materials. Although some do enjoy recreational usage of trailers as well.
Trailer stability can be defined as the tendency of a trailer to dissipate side-to-side motion. The initial motion may be caused by aerodynamic forces, such as from a cross wind or a passing vehicle. One common criterion for stability is the center of mass location with respect to the wheels, which can usually be detected by tongue weight. If the center of mass of the trailer is behind its wheels, therefore having a negative tongue weight, the trailer will likely be unstable. Another parameter which is less commonly a factor is the trailer moment of inertia. Even if the center of mass is forward of the wheels, a trailer with a long load, and thus large moment of inertia, may be unstable.
The FMCSA has established rules to maintain and regulate the safety of the trucking industry.According to FMCSA rules, driving a goods-carrying CMV more than 11 hours or to drive after having been on duty for 14 hours, is illegal.Due to such heavy driving, they need a break to complete other tasks such as loading and unloading cargo, stopping for gas and other required vehicle inspections, as well as non-working duties such as meal and rest breaks.The 3-hour difference between the 11-hour driving limit and 14 hour on-duty limit gives drivers time to take care of such duties.In addition, after completing an 11 to 14 hour on duty period, the driver muchbe allowed10 hours off-duty.
Unfortunately for the trucking industry, their image began to crumble during the latter part of the 20th century. As a result, their reputation suffered. More recently truckers havebeen portrayedas chauvinists or even worse, serial killers.The portrayals of semi-trailer trucks have focused on stories of the trucks becoming self-aware. Generally, this is with some extraterrestrial help.