How Does the Hydraulic Ironworker Work?
Brief Introduction of Diesel Forklift

The Types of Hoists

     A manual hoist is a suspended machinery unit that, by use of manual operation, is used for the lifting and lowering of a freely suspended (unguided) load. A manual hoist generally uses chain (roller or link) as its lifting medium. Operated by hand, there is an operator will pull down on one of the chain loops on one side of the chain. This will turn a pulley mechanism inside the chain hoist housing. When this pulley turns, it will lift up the end of the other chain which usually has a hook on the end.

       The basic hoist has two important characteristics to define it: Lifting medium and power type. The lifting medium is either wire rope, wrapped around a drum, or load-chain, raised by a pulley with a special profile to engage the chain. The power can be provided by different means. Common means are hydraulics, electrical and air driven motors. Both the wire rope hoist and chain hoist have been in common use since the 1800s; however, mass production of an electric hoist did not start until the early 1900's and was first adapted by Germany.

       A hoist can be built as one integral-package unit, designed for cost-effective purchasing and moderate use, or it can be built as a built-up custom unit, designed for durability and performance. The built-up hoist will be much more expensive, but will also be easier to repair and more durable. Package units where once regarded as being designed for light to moderate usage, but since the 60's this has changed. Built-up units are designed for heavy to severe service, but over the years that market has decreased in size since the advent of the more durable packaged hoist. A machine shop or fabricating shop will use an integral-package hoist, while a Steel Mill or NASA would use a built-up unit to meet durability, performance, and repairability requirements. NASA has also seen a change in the use of package hoists. The NASA Astronaut training pool for example utilizes cranes with packaged hoists.

       Another important product is the industrial chain hoist which is manufactured with motor housing that is made of aluminum alloy and is of rigid structure, but light weight. Its features include a transformer, magnetic contractor, phase error relay and push button pendant. They are branded products and can be bought in bulk orders. The limit switch of the chain hoist is fitted at top as well as bottom ends which shut off power automatically to prevent the load chain from running out. This saves the manual labor involvement and uses the tool up till its requirement. It is made up of alloy steel plate that ensures durable construction and the mechanical braking makes sure that the equipment stops even when it's overloaded. The mechanical brake is designed featuring double brake system that ensures safety and durability in hoist operation.



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