HOIST

AT ASC we realize hoists have two important characteristics: Power type and lifting medium. The power can be provided by different means. The most common means are hydraulics, electrical and air driven motors all of which ASC has available. The lifting medium is either wire rope, our specialty, wrapped around a drum or load-chain another product we proudly handle, raised by a pulley with a special profile to engage the chain. Both the wire rope hoist and chain hoist have been in common use for hundreds of years. ASC has over 40 years of experience and can help you design a cost-effective package for purchasing and moderate use, or it can be built as a built-up custom unit, designed for durability and performance.

Package units were once regarded as being designed for light to moderate usage, but over the last 40 years this has changed. Built-up units are designed for heavy to severe service. A machine shop or fabricating shop will use an integral-package hoist, while a Steel Mill or other heavy lifting needs would use a built-up unit to meet durability, performance, and repairability.

The most commonly used hoist in today’s worldwide market is an electrically powered hoist. These are either chain or the wire rope type. Many hoists are package hoists, built as one unit in a single housing, generally designed for ten-year life. See the Hoists Manufacturers Institute site for true life calculation which is based on load and hours used.

In today’s modern world in the North American market there are a few governing bodies for the industry. The Overhead Alliance is a group that represents Crane Manufacturers Association of America (CMAA), Hoist Manufacturers Institute (HMI), and Monorail Manufacturers Association (MMA). These product counsels of the Material Handling Industry of America have joined forces to create promotional materials and to raise the awareness of the benefits to overhead lifting. The members of this group are marketing representatives of the member companies.

ASC has the most common small portable hoists available, the two main types, the chain hoist or chain block and the wire rope or cable type. Chain hoists may have a lever to actuate the hoist or have a loop of operating chain that one pulls through the block (known traditionally as a chain fall) which then activates the block to take up the main lifting chain.

A hand powered hoist with a ratchet wheel is known as a “ratchet lever hoist” or, better known as a “Come-A-Long”. The original hoist of this type was developed 1919, and later commercialized in 1946. Ratchet lever hoists have the advantage that they can usually be operated in any orientation, for pulling, lifting or binding. Chain block type hoists are usually suitable only for vertical lifting.

For a given rated load wire rope is lighter in weight per unit length but overall length is limited by the drum diameter that the cable must be wound onto. The lift chain of a chain hoist is far larger than the liftwheel over which the chain may function. Therefore, a high-performance chain hoist may be of significantly smaller physical size than a wire rope hoist rated at the same working load.

Hoists are often designed with internal clutches to limit operating loads below this threshold. Within such limits wire rope rusts from the inside outward while chain links are markedly reduced in cross section through wear on the inner surfaces. Regular lubrication of both tensile systems is recommended to reduce frequency of replacement. High speed lifting, greater than about 60 feet per minute (18.3 m/min), requires wire rope wound on a drum, because chain over a pocket wheel generates fatigue-inducing resonance for long lifts.

The unloaded wire rope of small hand powered hoists often exhibits a snarled “set”, making the use of a chain hoist in this application less frustrating, but heavier. In addition, if the wire in a wire hoist fails, it can whip and cause injury, while a chain will simply break. Whatever your Hoist needs ASC has the answers.