Search results
Results from the WOW.Com Content Network
The first larger round hay baler was invented by Gary Vermeer in 1971. Allis Chalmers first introduced the small round rotobaler in 1947. Vermeer begins building large trenchers to lay underground pipelines in the 1980s. The first Vermeer horizontal directional drill is introduced in the 1990s. [9]
A chain trencher cuts with a digging chain or belt that is driven around a rounded metal frame, or boom. It resembles a giant chainsaw. This type of trencher can cut ground that is too hard to cut with a bucket-type excavator, and can also cut narrow and deep trenches. The angle of the boom can be adjusted to control the depth of the cut.
BWEs built since the 1990s, such as the Bagger 293, have reached sizes as large as 96 m (315 ft) tall, 225 m (738 ft) long, and as heavy as 14,200 t (31,300,000 lb). The bucket-wheel itself can be over 21 m (70 ft) in diameter with as many as 20 buckets, each of which can hold over 15 m 3 (20 cu yd) of material. BWEs have also advanced with ...
A 6-inch wide trench with a digging depth of 30 inches was the goal. [4] The first production trencher rolled off the assembly line in 1949. Called the "endless conveyor ditch digging machine," It was the first mechanized, compact service-line trencher developed for laying underground water lines between the street main and the house.
Roller chain and sprocket The sketch of roller chain, Leonardo da Vinci, Codex Atlanticus. Roller chain or bush roller chain is the type of chain drive most commonly used for transmission of mechanical power on many kinds of domestic, industrial and agricultural machinery, including conveyors, wire- and tube-drawing machines, printing presses, cars, motorcycles, and bicycles.
Modern tracks are built from modular chain links which together compose a closed chain. The links are jointed by a hinge, which allows the track to be flexible and wrap around a set of wheels to make an endless loop. The chain links are often broad, and can be made of manganese alloy steel for high strength, hardness, and abrasion resistance. [42]
A shield should not be confused with a shore. While they may serve a similar function, trench shoring is a different physical application that holds up the walls of a trench to prevent collapse. [1] In the US, use of a trench shield is governed by OSHA 29 CFR Part 1926.650-.652 Subpart P-Excavations.
Oil on canvas, 45.7 × 40.6 cm Metropolitan Museum of Art, New York: Woman Holding a Balance, also known as Woman with a Balance [8] 1662–63 or c. 1663–64 [8] Oil on canvas, 42.5 × 38 cm National Gallery of Art, Washington: A Lady Writing a Letter: 1665–66: Oil on canvas, 45 × 40 cm National Gallery of Art, Washington: Girl with a Pearl ...