Mechanical Couplings and Clutches: Types and Applications

Rigid Couplings

Rigid couplings are those which have a rigid connection between the two axes. Generally, they are built with two plates that are joined together by means of screws. They do not allow any relative movement between the two elements joined.

Torque Limiters

Torque limiters are rigid, maintaining the transmission of the effort while not exceeding a certain value. The most basic are constructed by a cross pin which is sheared when the torque limit is exceeded. They are simple and economical but have the disadvantage of being removed each time they are sheared. They are used as security features.

Elastic Couplings

Elastic couplings are those that allow some relative movement between the two axes united. Therefore, they have some elastic element that deforms under point and recovery efforts in the operating position in the regime. They are in widespread use in the couplings of motors.

Mobile Couplings

Mobile couplings are those that allow a degree of mobility of one axis over the other.

Oldham Coupling

Oldham couplings transmit motion between two shafts that are not coaxial, that is, it allows radial displacement.

Cardan Joint

Cardan joints transmit motion between two shafts to form a certain angle, although this varies during transmission. It has a central cross linked with two forks.

Governed Clutches

Governed clutches are those couplings that allow maintaining or interrupting the continuity of movement between axes. The change in continuity/discontinuity is carried out through some specific friction actuator. When the continuity of movement is achieved through the discs, they allow the drive during operation of the machine. They are subjected to wear and have a limitation in terms of torque transmitted.

Automatic Clutches

Automatic clutches are those that act by joining and disjoining elements taken to a certain work.

• Centrifugal Clutch: By increasing engine speed, the automatic clutch is produced by a centrifugal action on the mobile masses, decoupling by reducing revolutions below a certain threshold.
• Torque-Limiting Clutches: These produce the decoupling when a certain torque is exceeded, turning to give continuity to the movement when it exceeds its preset limit, so that, after the over-exertion, the link will not recover, unlike other clutches.
• One-Way Clutches: These transmit the movement only in one direction of rotation of the drive shaft.
• Ratchets: Convert a reciprocating motion into another rotation in a particular direction.

Accumulators

Kinetic Energy Accumulator

Kinetic energy accumulators are generally used to homogenize movements. The generation of a movement can produce periodic irregularities. The energy accumulated by the wheel is given by: E = 1/2 * I * W^2.

Elastic Accumulator

The elastic component of a coupling, which accumulates a small amount of energy at the instant of effort, is released in the moments after, softening the potential impact during operation.

Dampers

Dampers are devices designed to dissipate small amounts of energy. Their mission is to control the energy released by elastic elements. Elastically stored energy tends to produce symmetrical distortion.

Rolling Elements

Rolling elements consist of two rings between which a series of rolling elements are guided by a cage.