Horse collar of the Oseberg ship burial). The problem with a breastcollar harness was that the actual shafts of the cart, chariot, or other vehicle are attached to a surcingle around the barrel of the horse. The breastplate primarily kept the surcingle from slipping back, not as the primary pushing object. This results in the horse literally pulling the load, a less efficient use of the animal. The modern breastcollar has traces which transfer the pull directly from the breastcollar, but a horse collar still is more effective for pulling heavy loads. After the breastcollar harness, the next and final evolutionary stage
Timing belt (camshaft) overhead cam four-cylinder design which used a timing belt, a configuration which became one of the most common. A timing chain, also called a sync chain, is used on tandem bicycles, to synchronize crank movement between the captain (front rider) and stoker (rear rider). As with auto engines, proper tension of the timing chain is necessary to prevent premature wear of the drivetrain components. Tension is adjusted by means of an eccentric bottom bracket. Timing belt (camshaft) A timing belt, timing chain or cambelt is a part of an internal combustion engine that synchronizes the rotation of the crankshaft and