True Vertical Lift for Precise Lifting
Welcome to the Hoist Guy's blog! Does your lifting application need true vertical lift? In this post, we’ll explore double-reeved hoists and options for precise picks and placements.
by Andrew T. Litecky on May 31, 2017
In the world of overhead material handling, there is lifting, and there is precise lifting. When a high degree of accuracy is required to make a pick or place a load, the application calls for a hoist with “true vertical lift” capability. This degree of accuracy is often required for manufacturing or specialty applications in the pharmaceutical industry or injection molding.
What is true vertical lift? It’s when a hoist can lift the hook straight up and down with no hook drift to pick up or put down in an exact spot. In general, single-reeved wire rope hoists operate with a certain amount of natural drift, and for many applications, that’s not a problem. However, when the load must be lifted or lowered to a specific spot, the industry provides double-reeved wire rope hoists.
These units operate with wire rope that’s fed through a series of sheaves in the hook block and hook frame. They’re also wound on two separate sides of the wire rope drum called left-handed and right-handed grooving. The standard reeving on cataloged hoists with true vertical lift is “two part double” which has four separate parts of wire rope. Also common is “four part double” reeving made from eight separate parts of wire rope. More wire ropes create a mechanical advantage, allowing for the handling of heavier loads at a slower speed.
It’s important to note that chain hoists already have true vertical lift built in, but many prefer the smooth operation of wire rope. Also, there are some European hoists designed to minimize hook drift with an oversized wire rope drum, however, this doesn’t eliminate the problem.
For true vertical lift hoists, Shupper-Brickle recommends a few brands. Acco’s double-reeved Work-Rated and Speedway hoists use parallel mounting and takes up less space horizontally. Meanwhile, Yale’s cross-mounted, double-reeved Cable King unit is shorter vertically for excellent headroom. We also recommend Electrolift hoists for ultra-low headroom and true vertical lifting.
Have an application for precision lifting? Contact us! We’ll assist you to find the equipment that best meets your needs and budget.
Want more Hoist Guy? Read some of our other blogs posts to answer questions such as: Why Not Just Anyone Should Fix Your Hoist or check out this old school diagram showing the mechanical advantage of tackle systems.