The motion-control systems designed at Aberdeen Dynamics are among the most cutting-edge technologies in the field, featuring advanced human-machine interfaces and integrated computer systems that are at the forefront of human innovation. Although this continuous advancement is one of our key goals, we also implement technologies that have been a reliable source of mechanical power for hundreds of years: modern versions of simple machines such as the hoist and winch.
When choosing your equipment, it’s important to understand the basic concepts and key differences between these two common and often critical elements. We’ll break down the specific applications of a hoist versus a winch, explain how they work, and help you make an informed choice about which system to utilize for your specific needs.
Mechanical Advantage: The Key to Success
Hoists, winches, and other lifting technologies operate by utilizing the principle of mechanical advantage, which occurs when the force applied to a device is multiplied by the leverage that is created. Devices that take advantage of this principle are referred to as simple machines, and they include levers, wheels, pulleys, wedges, screws, and inclined planes. Hoist and winch systems use wheels and pulleys to generate force, allowing them to move much heavier weights than would be possible without leverage.
While the machines that underpin hoists and winches may be “simple,” they serve as the basis for many technologies, some of which are extremely sophisticated. Modern industrial systems utilize high-powered motors, high-tensile-strength cables, and electrical control systems to generate far greater lifting power than has ever been possible before.
Hoist or Winch?
While, conceptually, hoists and winches operate in much the same way, they have a key difference when it comes to their actual function: A hoist is designed to lift objects vertically, while a winch hauls them horizontally. Both devices have a wide variety of applications across dozens of different fields, and it’s likely that any major manufacturing or construction activity will utilize both.
The fact that hoist and winch systems have different applications, however, means that they also have key differences with regard to their construction and operation. We’ll look at those differences below.
How a Hoist Works
Since a hoist is responsible for lifting and lowering objects, safety is of the utmost concern. The major difference between a hoist and a winch is the braking system. With hoists, multiple braking systems are typically used to ensure the lifted load can be suspended safely. Sometimes, up to three braking systems may be required, depending on the governing body that regulates an industry (ANSI, API, OSHA, ISO, etc.).
With a hoist, planetary gearing is the most common way to gain the mechanical advantage needed for hoisting. Planetary gearing is defined as a gear system with a central gear that drives multiple gears that rotate around it inside of a ring gear. Planetary gearing allows for large reduction/multiplication ratios in a small area, allowing for exceptional power density. For safety and control, the braking system is connected to the central gear or sun gear through a hydraulic or electric motor. Since the torque seen at the hoist cable drum passes through the gear reduction, the brake size needed to hold the suspended load and torque can be much less.
Hoists typically use two different styles of braking: dynamic and static. Dynamic braking is performed through the hydraulic motor with a counterbalance valve that restricts and controls the oil flow passing out of the motor. Static braking is typically performed with a spring-applied, hydraulically released multi-disc friction brake. These brakes are small in diameter and perform as a parking brake to help in holding the load when it is not in motion. Depending on the governing body in which the hoist is designed, an additional drum band brake or auxiliary brake may be added to the hoist as a direct-to-cable drum mechanical lock.
Breaking strength ratings for hoists tend to be much higher than winches due to safety concerns. Most hoists have been tested to a breaking strength that is 4:1 higher than the rated load and can be as much as 10:1, depending on the specification it is designed for. Examples of hoist applications include cranes (mobile and stationary), oil drilling rigs (personnel handling), shop cranes, and tower cranes.
How a Winch Works
The term “winch” refers to a mechanical device that pulls or drags a load across a horizontal plane. Compared to hoists, winches are much more cost-effective and simplistic in design. Although planetary gearing is used in the winch market today, many winches are designed with a spiral-cut worm and gear design. The worm gear design uses the inefficiency of the gear contact to help control and stop the load.
Additional drag brakes are added to the worm gear shaft to assist in slowing the worm. Planetary winches (not hoists) do still use a similar technology in braking with a counterbalance valve, but the safety factors are typically reduced to a 2:1 ratio. A worm gear or planetary recovery winch is never intended to be used to hoist and suspend a load. Examples of winch applications include rollback wreckers, lowboy trailers, and horizontal industrial pulling.
Which Do I Need for My Application?
As mentioned above, in most industrial and manufacturing applications, you will likely see both hoists and winches used regularly, although not interchangeably. Hoists are more effective if there is limited horizontal space, while winches are preferred if upward movement is not practical.
Selecting the right winch or hoist for your application can be perplexing. Aberdeen Dynamic’s team of Engineers and Account Managers with years of winch and hoist application experience would be glad to assist in this task. We can help simplify and expedite the process and find the right product for you.
If You Have Further Questions
At Aberdeen Dynamics, we specialize in many types of engineered systems, including hoists and winches. We also provide related technology, including control panels that allow operators to interface with these important machines more smoothly and safely than ever before. Our focus is on optimizing both performance and safety to ensure that our customers can successfully achieve their ongoing business goals. If you’re in need of a custom hoist and winch system specifically suited to the needs of your specific business, contact us to discuss your options.