The purpose of power transmission is to move energy from its point of generation to a place where it can be applied for useful and productive work. This definition of power transmission may create visions of electricity passing through a wire. There are many forms of power transmission that do not include electricity or other forms of energy. The key is the concept of the transmission of power from one location to another.
Included in the broader definition of power transmission are conveyor belts, chains, pulleys, bushings, bearings, and linear actuators that redirect and guide various types of motion and energy. The rule for the manufacture of power transmission equipment is that they have to be sturdy and durable enough to withstand constant stress.
One of the most common forms of power transmission mechanisms is the ball bearing that allows for motion between two objects without creating friction. Ball bearings can move heavy objects and materials with less effort. The use of ball bearings is critical in the creation of smooth and uniform movement, which helps in avoiding damage to equipment and parts.
A fascinating mechanism that has a wide range of use is a ball screw device that changes rotational or circular motion into linear or straight motion. The transformation created by a ball screw is a crucial part of machines and mechanical movement. Ball screws can be found in nearly every form of manufacturing equipment since such conversion is a necessary part of heavy duty equipment operation.
For many years, the basic electric motor has been a reliable source of energy for manufacturing. Since electric motors can be designed in several different sizes, they can be applied to any form of machinery. The energy created by an electric motor is caused by the electromagnetic interaction between a coil and a set of magnets, which produces mechanical force. The types of energy from an electric motor can be direct or alternating depending on the requirements of the application.
Regardless of the type of energy or power being produced, there has to be some form of mechanism for stopping the flow of power. As demonstrated by the brakes on an automobile, this form of force is created by materials that create friction between surfaces. The purpose of friction materials is to control, slow, or inhibit motion. The main characteristic of friction materials is their high friction coefficient.
Much like ball screw devices, gears are a transfer mechanism used to change torque. They are composed of equally spaced teeth that come in a variety of designs and shapes that smoothly mesh. The various types of gears include spur, spline, and planetary, which are incorporated into a machine based on the type of torque required.
One of the simplest forms of power transmission devices is the quick release coupling that allows for easy and immediate connection or disconnection of fluid lines. The idea behind quick release couplings is to make the connection or disconnection with a minimum of effort and the least amount of process interruption. Normally, quick release couplings are designed to replace threaded or flanged connections for hydraulic tools.
A speed reducer works somewhat like a gear or ball screw device. The purpose of a speed reducer is to redirect the output of a high speed motor to a mechanism that operates at a lower speed. A set of gears in the speed reducer provide the necessary mechanism for the reduction in speed. The ratio of the input gear to the output gear is the reason for the exceptional performance of speed reducers.
A well-known form of power transmission mechanism is timing belts, which are used for power transmission where maintaining a drive ratio is important. Timing belts are the most widely used form of power transmission devices and are found in engines, large machinery, and stepper motors.
The safe and smooth transmission of power is an important part of the operation of machinery and vehicles. Power transmission devices provide the proper and safe ways to complete the exchange in an efficient and effective way.
Electric motors are used to convert electrical energy into mechanical energy. These motors are comprised of electric coils and magnets.
Friction materials are products used to slow or inhibit movement, and they are used in many different types of machinery to control or stop processes. The two main criteria for good friction materials are a high coefficient of friction and good energy absorption.
Gears are devices used to transfer torque from one part of a mechanical system to another. Equally spaced teeth along the outside of the gear interlock with the teeth of other gears to transfer rotational motion.
Quick release couplings are simple mechanical devices that permit easy and immediate connection or separation of fluid transmission lines with a minimum of stoppage time and spillage.
A shaft coupling is used to join two shafts together and to ensure that the two shafts rotate together.
Speed reducers are used to redirect the output of a high-speed motor to another component at a lower speed. Gears within the speed reducer provide the mechanism for reducing the output speed of the motor. 
Timing belts are used for power transmission or to interchange linear motion and rotary motion where maintaining a specific drive ratio or high loads are important.
They are most widely used in the regulation of internal combustion engine operation. Linear position systems are a common non-automotive application of timing belts.