There are many different kinds of auto wrecker service beds used with the manufacture of tow trucks, or wreckers, from simple one armed booms to roll back designs. With heavy towing applications, a twin, swivel wrecker bed is usually used, this is mainly due to its ability to pull simultaneously in two separate directions or differing angles. The most commonly seen is a vehicle getting raised up by the bumper using a hook coming from the wreckers boom arm. However, now with the newer modern tow truck designs, this very rarely happens, instead, the tow truck will raise and tow a vehicle using an apparatus called a wheel lift, which extends from the back of modern wrecker beds.
Though not normally used for standardized towing, many wrecker beds come with a boom which is housed in the center of a bed. The earliest types of wrecker booms came with a solidly mounted steel boom which had a swivel pulley connected at the end of the boom. A drum which contained heavy steel cable was used with the help of a power take off, or PTO, operated by the tow trucks engine, via its transmission. The cable was snaked up the boom and pushed through the pulley, where it was connected to a steel hook. The hook was then attached to a vehicle getting towed, and the cable was pulled back into the drum, thus raising the wheels of a vehicle off of the ground, allowing it to be towed safely.
Modern auto wrecker service beds have one or more hydraulic booms which are raised, lowered or swung left or right using hydraulic cylinders which are fed by its pump on the tow trucks engine. The booms use steel cable running up and through a pulley which is then mounted on the end, very similar to its earlier models. This cable, is controlled by an electrical motor. The booms are used mostly for recovery of wrecked vehicles, or lifting a vehicle up from an embankment or ditch. The lifting of a vehicle is done with the help of a wheel lift, this is a hydraulically operated device which is found at the rear of a tow truck.