Industrial Clutch CBA Air Actuated Combination Clutch and Brakes

clautch and brake system

Table of Contents


Industrial Clutch Products designs and manufactures a complete line of dry and oil-immersed clutches and brakes, ranging in size from 5 to over 48 inches in diameter, with torque capacities exceeding eight million pound-inches. We also specialize in hydraulics
and controls for use with our own clutches and brakes, or as stand-alone systems, utilizing the latest advancements in microprocessor-based controls.

We pride ourselves in our ability to respond to customers needs for standard, modified, and custom designs for unique or volume requirements. We are dedicated to ongoing research & development programs and full-scale testing, thus eliminating using the customer’s installation as a test site. We are also a company who believes in the importance of strong supplier interaction.


Air or Hydraulically Actuated Combination Clutch-Brakes

The Industrial Clutch CBA Clutch/Brakes  Model CBA is an oil-immersed, combination clutch/brake, utilizing a self-contained cooling oil pumping system. It is a quill-mounted unit that may be used for either end of shaft or through-shaft designs. The Model CBA is designed to be compatible and complementary to our dry units.

A clutch is a device that is installed between a power source and a load so that the power source can be connected or disconnected from the load upon command. A brake is a device that is installed between a fixed member and a load so that the load can be disconnected or connected to the fixed member upon command. Refer to the schematic shown in FIGURE 1.

Install clautch and brake
Install clautch and brake

A clutch or a brake performs two basic functions:

  1. Transmits the normal and peak load torques with a suitable service factor.
  2. Dissipates the heat generated during the engagement

Maximizing system reliability, minimizing engagement shock loads, and providing a clutch or brake unit that exhibits suitable durability must be the goals of every installation.

All clutches and brakes manufactured by Industrial Clutch Products transmit TORQUE by friction. Once the geometry of any unit is fixed, its torque transmitting characteristic is determined by the magnitude of the force applied to the friction surface and the coefficient of friction at this surface.

All clutches and brakes have a speed differential between their input and output members when they are disengaged. When engaged, there is no speed differential since they are “locked-up” and performing one of their primary functions of transmitting load torque. Therefore, to go from a disengaged condition to one of being engaged, a clutch or brake must go through a slipping phase until “lock-up” occurs. Note that the unit must transmit torque to or from the load during this slipping phase or no change in load motion will occur.

calculation Torque clautch and brake
calculation Torque clautch and brake

During engagement, the magnitude of the clutch or brake torque multiplied by the speed differential over the engagement time period is proportional to power. This manifests itself as HEAT. The clutch or brake unit must successfully dissipate this heat in accordance with the frequency of engagement the application requires. Refer to the schematic shown in FIGURE 2.

Product Features

  • Pneumatic or hydraulic actuation.
  • Accommodates bi-directional rotation.
  • Clutch torque capacities ranging from 30,000 to 2,500,000 pound-inches.
  • Brake torque capacities ranging from 8,000 to 400,000 pound-inches.
  • External cooling option.
  • Combination Clutch/brakes by design eliminate the possibility of engaging clutch and brake simultaneously.

Air or Hydraulically Actuated Combination Clutch-Brakes

Performance Characteristics

The Model CBA combination clutch-brake is an oil immersed unit utilizing a self-contained cooling oil-pumping system and capable of being actuated with either air or hydraulic pressure. These units are capable of running at higher speeds and greater cyclic frequencies without exhibiting the wear magnitudes common to clutches and brakes operating dry under the same conditions.

Reliability and longevity are the most important features these units have to offer and find usage in those applications requiring the ultimate in clutch and brake performance. Over fifteen years of field experience shows intervals between maintenance and machine up-time to increase from five to ten times when oil immersed units are used as direct replacements for those operating dry.

Industrial Clutch Products has designed the Model CBA unit to be compatible and complementary to their dry unit products. All of the desirable features found in our standard line of dry products were carefully evaluated for incorporation into the Model CBA combination clutch brake. The user may expect the lowest possible driven inertia; fastest speed of response; and the same high
quality ruggedness contained throughout our product line.

The Model CBA unit was designed and developed as part of our commitment to provide wide ranging and usefully products for the heavy industrial marketplace. As a result, the user has another level of performance from which to choose


  • Combination clutch-brake eliminates the possibility of clutch-brake fight
  • Increase in lining life
  • Increase in reliabillity
  •  Impervious to adverse operating environments
  •  Low driven inertia
  • Fast speed of response
  • High cyclic rates
  • High operating speeds


The Model CBA combination clutch-brake is arranged so that it may be mounted in and end of shaft or thru shaft configuration. The clutch driving members attach to the flywheel or input power source. The stationary brake members are attached to the machine frame by the use of a quill member which also provides a path for moving the cooling oil into and out of the unit if the application requires external cooling. Refer to Figure 1 and Figure 2 for a typical arrangement of an outboard (CBA) and thru-shaft (CBAT)
mount respectively.

The unit may be provided with either pneumatic or hydraulic actuation chambers as well as a variety of brake springs to accommodate the clutch and brake torque requirements. Due to the many types of machinery configurations, it is
often more convenient to house the clutch-brake unit within a user provided mounting cavity.

CBA Combination Clutch Brake
CBA Combination Clutch Brake

The Model CBA contains its own circulating oil-pumping system which pumps oil through the disc packs from either direction of rotation anytime the input member rotates. Refer to Figure 3. If external cooling is required due to the speed and cyclic rate, the internal pump output is directed from the outer housing cavity through the quill/brake support member and external cooler where the engagement heat is removed. Cooled oil then returns through the quill/brake support member into the disk pack where engagement heat is transferred to the oil. This heated oil is then pumped back to the cooler for heat removal.

If external cooling is not required, the circulating pump simply moves the oil internally from the outer housing cavity through the disk packs and back to the housing cavity where the engagement heat is transferred through the rotating housing into the surrounding atmosphere.

The ability of the CBA combination clutch-brake to continuously and effectively transfer large quantities of energy in this manner is the key factor to its longevity and reliabililty. In addition, the torque transmitting members, being lubricated by this same oil, are well suited to carry the heavy duty industrial type loads these models encounter


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