Line shafts and belts: mechanical power transmission required a maze of whirring devices.(Assembly Then & Now)

In the mid-19th century, manufacturing engineers considered mechanical power transmission to be state-of-the-art technology. Before the advent of individual electric-drive motors in the early 20th century, a mind-boggling maze of overhead line shafts, countershafts, leather belts, belt shifters, pulleys and gears were a common sight in manufacturing plants.

Complex networks distributed power to machine tools and assembly equipment. However, they were cumbersome, loud, finicky and dangerous. The devices also required constant maintenance and repair.

Early multistory factories relied on a central power source, such as a steam engine or a water wheel, which was located in the basement or on the first floor. It turned a vertical main shaft that extended through each floor of the facility. On every floor, one or more line shafts attached to the ceiling connected to the main shaft and extended the length of the floor. Each line shaft turned as the main shaft turned. A series of belts, gears and pulleys attached to each line shaft powered individual machines.

Shafting was supported by metal hanger-plates that were attached to the bottom faces of girders, beams and joists. They were spaced according to either the number of machines, the power load taken off or the layout of the shop, with an 8 to 10 foot span between hangers. Sections of the line shaft were joined together by a wide variety of coupling devices, such as exposed flanges.

From a main shaft on each floor, power was distributed to several countershafts. Pulleys transferred power from the shaft that connected with each machine. Belts extended downward from the shaft to the machinery below it. Sometimes, belts ran through slots in the floor to power equipment …