Solution Summary: Air Manipulator Hoist
An air manipulator hoist is an engineering control that may help reduce heavy or repetitive lifting. The hoist has a stationary cable that can be hung from an immovable object. A standard 5 HP air compressor powers the movable cable attached to the load.
An air manipulator hoist has a stationary cable exiting one side, and a movable cable exiting the other (Figure 1). The stationary cable has a hook at the end, which is hung from a fixed object. The movable cable is secured to the object being moved. A 3/8 inch air supply hose connects the hoist to a 5 HP air compressor to provide a lifting force. The hoists have up and down buttons that can be pushed with one hand. The other hand can stabilize the load, if needed. There are many manufacturers of air manipulator hoists.
Figure 1. The Harrington AH Mini-Cat Air Manipulator Hoist
The AHA Mini-Cat Air Manipulator has models with maximum lifting capacities of 250-500 lb and maximum lifting speeds of 41-47 feet per minute (fpm). Standard lifting length is 10 ft, and it consumes from 19-34 cubic feet of air per minute (cfm).
The Coffing Air Manipulator Hoist has a maximum lifting capacity of 300 lb and maximum lifting speed of 36 fpm. Standard lifting length is 6 ft 6 in, and it consumes 21.2 cfm (Figure 2).
Figure 2. The TMM Air Manipulator Hoist
Heavy lifting can cause low back disorders, such as muscle strain or a disc herniation (“slipped disc”), which is bulging of disc material possibly pressing on the spinal cord or nerves that go into the leg. Overworking the back muscles can result in strains. Use of a air manipulator hoist may reduce the risk of disc herniation, back strains, and other MSDs associated with lifting.
How Risks are Reduced:
Excessive loads are placed upon the back when one or more laborers lift heavy loads. An air manipulator hoist can lift heavy loads with minimal effort from the laborer.
Manufacturers and safety and health experts believe that using an air manipulator hoist can decrease the risk of lifting related injuries. Harrington Hoists and Cranes claims that their AH Mini-Cat is “designed to support the special repetitive working practices of assembly line and workstation areas in a wide variety of industries.”
Safety and health experts believe that hoists reduce the amount of manual material handling, a known risk factor for low back disorders. Hoists are beneficial when forklifts are unavailable for heavy lifting.
Effects on Productivity:
An air manipulator hoist can increase productivity on the worksite.
All air manipulator hoists should be operated in compliance with the operator’s manual.
Since air manipulator hoists are fixed in one place, their use may be limited at construction worksites.
Dan Anton, PT, PhD, ATC; Kevin Wright, SPT; and Benjamin Tucker, SPT – Eastern Washington University
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