Search results
Results from the WOW.Com Content Network
A Gunter's chain showing the individual links. The link (usually abbreviated as "l.", "li." or "lnk."), sometimes called a Gunter’s link, is a unit of length formerly used in many English-speaking countries. In US customary units modern definition, the link is exactly 66 ⁄ 100 of a US survey foot, [1] or exactly 7.92 inches or 20.1168 cm.
An improvement on the loose-coupled train is the "Instanter" coupling, in which the middle link of a three-link chain is specially triangular shaped, so that when lying "prone" it provides enough slack to make coupling possible, but when the middle link is rotated 90 degrees, the length of the chain is effectively shortened, reducing the amount ...
Watt's linkage consists of three bars bolted together in a chain. The chain of bars consists of two end bars and a middle bar. The middle bar is bolted at each of its ends to one of the ends of each outer bar. The two outer bars are of equal length, and are longer than the middle bar. The three bars can pivot around the two bolts.
A link-and-pin coupler Transition era AAR knuckle coupler. The gap in the knuckle accommodates the link of a link and pin coupler and the vertical hole in the knuckle accommodates the pin. Link and pin coupler combined with side buffers on a Panama canal mule. The link-and-pin coupling was the original style of coupling used on North American ...
Linkages may be constructed from open chains, closed chains, or a combination of open and closed chains. Each link in a chain is connected by a joint to one or more other links. Thus, a kinematic chain can be modeled as a graph in which the links are paths and the joints are vertices, which is called a linkage graph.
The draw chain used between each pair of vehicles includes a screw which is tightened after coupling to shorten the chain and keep the buffers pressed together. Such is known as a 'screw coupling'. Historically, coupling chains were no more than that, a short length of heavy chain (typically three links long) with no adjustment.
One link is a hundredth part of a chain, which is 7.92 inches (20.1168 cm). [7] The surveyor's chain first appears in an illustration in a Dutch map of 1607, [8] and in an English book for surveyors of 1610. [9] In 1593 the English mile was redefined by a statute of Queen Elizabeth I as 5,280 feet, to tie in with agricultural practice.
(That is also the common way of coupling locomotives to or from wagons, faster than unscrewing the link.) British locomotive-hauled passenger carriages adopted a dual coupling system in the 1950s. They have retractable buffers and a central Buckeye automatic knuckle coupler that lowers to reveal a hook for a screw-type chain coupling. When in ...