Mechanical, Pneumatic or Hydraulic Brakes: What is Best for My Application?
When you’re trying to decide which type of industrial brake is best for your particular application (such as mechanical, pneumatic, or hydraulic brakes), it’s important to understand both the reasons for braking and the differences in the types of caliper disc brakes available for industrial equipment and on- and off-road braking applications.
Understanding the Reasons for Braking
1. Dynamic Braking
The primary reason for braking is, of course, to get something to stop—also known as “dynamic braking.” A disc is moving and your goal is to get it to come to a complete stop. Any on-or-off-road vehicle, aircraft service vehicles, golf carts, construction machinery or even wind turbines refer to this as “active braking.”
2. Holding Position (Static)
A second reason involves a “holding position,” which is common with industrial machinery with rotating parts. A winch is a good example of static braking. When payout or reeling is complete, a holding position can be of critical value.
3. Controlling Speed
Lastly, there’s “tensioning,” which falls between dynamic braking and holding, and is used for controlling speed. Anything that comes on a roll, such as newspaper, foil, or tape, is manufactured by a web handling system and involves tensioning. Tensioning brakes are applied often, so their pads have high wear rates, but are easily replaceable.
However deciding on which type of brake to use will depend on what’s best for your application, so let’s “brake it down” further…
Understanding What Powers Brakes
There are as many types of brakes as there are countless applications, however, there are three main categories of brakes, determined by how they are powered: mechanical, pneumatic, and hydraulic brakes. Here are some of the ideal applications for each.
1. When to Use Mechanical Brakes
Just as it sounds, mechanical brakes are actuated by the use of a lever or screw, for which no power supply is required. Mechanical brakes are best suited for applications that require static braking that can be manually applied. Some examples and applications are:
- Parking brakes
- Emergency systems in elevators–while the brakes are typically spring-activated, they require mechanical force to release
- Conveyor systems
- Stopping 5-10kw class wind turbines
Mechanical brakes can be well suited when nothing more elaborate is required. You pull a lever and the system stops.
2. When to Use Pneumatic Brakes
The power used in these type of brakes is air, supplied primarily by a compressor. Air brakes typically operate at lower pressures than hydraulic brakes, around 70-120 PSI for most applications.
Pneumatic brakes are commonly used on industrial machinery requiring brakes because manufacturing facilities most often have a pneumatic compressor on site. For this reason, we typically see pneumatic brakes in factories where there is machinery with rotating parts, but they can also be used in applications like:
- Manipulator arms or robotics
- Hose reels to moderate the tension and prevent reverse winding
- Railway systems to apply or release brakes throughout the entire train simultaneously
- Lift trucks used in warehousing and material handling settings
- Amusement park rides, such as roller coasters, Ferris wheels, and drop towers, employ pneumatic brakes for controlled stops and smooth operation
3. When to Use Hydraulic Brakes
Most often these brakes are powered by hydraulic oil for industrial machinery or DOT 3/4 automotive brake fluid (polyethylene glycol). When pressurized the fluid creates substantial force in terms of PSI. Hydraulic brakes tend toward the high pressures needed for proper stopping, holding, or tensioning, such as:
- Web and wire tensioning
- Heavy duty indexers
- Heavy equipment and industrial machinery like cranes and presses for reliable stopping power and precise control
- Elevator systems–hydraulic pressure is utilized to engage or release the brakes to ensure safe stops at designated floors.
Be sure to specify the fluid type to ensure your brake is equipped with fluid-compatible seals.
Hydraulic power supplies are common in most vehicles, such as commercial and off-road type braking. These brakes can be service brakes to stop the vehicle, or used to hold position on machinery. For example, a utility vehicle may have a wire cable reel that needs to be controlled and hydraulic power is available.
Air vs. Hydraulic Brakes
We often see hydraulic brakes used in applications requiring higher torque braking. Oil field and mining equipment typically use hydraulic brakes for this reason. Wind turbines from 5–50 kw often have pneumatic (or air) brakes. Wind turbines at 50 kw and higher most often have hydraulic brakes.
One More Decision
Your application may require one of two types of brakes, “Double-Acting Brakes” (with two live sides) or “Floating Brakes” (with a single live side).
1. Double-Acting Brakes
A double-acting brake is fixed mounted with pistons on each side that, when actuated, engage against the brake disc. It’s critical for the brake to be well-centered over the disc, otherwise, the brake pad on one side will wear out faster than the other.
2. Floating Brakes
The floating brake with a single live side is the most common type. This type of brake has a piston (or pistons) on one live side, which presses a friction pad on the rotor (or disc) when engaged. A floating brake is mounted on rods, bushings, or shoulder bolts that are smooth and allow the brake to move when engaged. The disc is fixed, which allows the brake to center itself so the live side and dead side pads brake with equal and opposing clamping force.
Read more: Branham Brakes for Vintage Snowmobile Racing
These are the basic things to consider when choosing the best brake for your industrial or vehicular off-highway application. W.C. Branham has a wide line of brakes including pneumatic or hydraulic spring applied and hydraulic/mechanical combinations for many different types of applications.