Machine Tools

A machine tool is a machine for shaping or machining metal or other rigid materials, usually by cutting, boring, grinding, shearing, or other forms of deformation. Machine tools employ some sort of tool that does the cutting or shaping. All machine tools have some means of constraining the workpiece and provide a guided movement of the parts of the machine.

Today machine tools are typically powered other than by human muscle (e.g., electrically, hydraulically, or via line shaft), used to make manufactured components  in various ways that include cutting or certain other kinds of deformation.

With their inherent precision, machine tools enabled the economical production of interchangeable parts.

Hydraulic Brakes

The hydraulic brake is an arrangement of braking mechanism which uses brake fluid, typically containing ethylene glycol, to transfer pressure from the controlling mechanism to the braking mechanism.

In this system, when the brake pedal is pressed, a pushrod exerts force on the piston(s) in the master cylinder, causing fluid from the brake fluid reservoir to flow into a pressure chamber through a compensating port. This results in an increase in the pressure of the entire hydraulic system, forcing fluid through the hydraulic lines toward one or more calipers where it acts upon one or two caliper pistons sealed by one or more seated O-rings (which prevent leakage of the fluid).

The brake caliper pistons then apply force to the brake pads, pushing them against the spinning rotor, and the friction between the pads and the rotor causes a braking torque to be generated, slowing the vehicle. Heat generated by this friction is either dissipated through vents and channels in the rotor or is conducted through the pads, which are made of specialized heat-tolerant.

Subsequent release of the brake pedal/lever allows the spring(s) in the master cylinder assembly to return the master piston(s) back into position. This action first relieves the hydraulic pressure on the caliper, then applies suction to the brake piston in the caliper assembly, moving it back into its housing and allowing the brake pads to release the rotor.

The hydraulic braking system is designed as a closed system: unless there is a leak in the system, none of the brake fluid enters or leaves it, nor does the fluid get consumed through use.

Mechanical Power Brakes

Power brakes are a system of hydraulics used to slow down or stop most motor vehicles. It uses a combination of mechanical components to multiply the force applied to the brake pedal by the driver into enough force to actuate the brakes and stop a vehicle that can weigh several tons. The brake pedal is connected to the vacuum booster which is the first step of the force multiplication. The booster passes the force to the master cylinder which compresses a liquid and forces it through the brake lines to the brakes themselves. The liquid that is pushed into the brakes activates the brake calipers which in the case of disc brakes, push against the brake rotor causing friction that slows and eventually stops the rotation of the vehicles wheels. In drum brakes, pistons push two shoes against the brake drum accomplishing the same effect.

Pneumatic Power Brakes

Electronically controlled pneumatic brakes are a type of modern railway braking system which offer improved performance compared to traditional railway air brakes.

ECP braking uses electronic controls which make it possible to activate air-powered brakes on the cars. On an ECP-equipped train, the cars are equipped with a Trainline Cable that runs parallel to the brake pipe down the length of the train. This cable is used to supply power to the electronic components installed on the cars. The cable also doubles as a communication medium that allows the locomotive to send commands and receive feedback from the cars and the End of Train.

ECP provides many benefits over the traditional braking system. For example, since all the cars receive the brake command at the same time, the brakes are applied uniformly and instantaneously. This provides much better train control, shortens the stopping distances, and leads to a lower risk of derailment or of coupling breakage.

Also with ECP, the brake pipe remains charged during operation. This allows the reservoirs on the cars to continuously charge making it more difficult to exhaust the air supply used for braking. Further, since the cars can also send their status to the locomotive at the front, the engineer can monitor the state of the train and know at any given time the braking capabilities available.