Basic and Complex Mechanical Functions

• A component is a part of a technological system.

• A technological system is an organized set of interconnected components that influence one another to accomplish an overall function.

• The mechanical function is the role fulfilled by a component or a mechanism in a technological system.

Here are two examples referring to a door with hinges and screws.

A basic mechanical function is the role fulfilled by a component in a technological system.

A component can perform more than one basic mechanical function.

Linking is the function provided by a component that holds different parts of a technical object or technological system together.

A screw connects a bicycle’s brake pads to the brake caliper. The screw is the linking component.

Guiding control is the function provided by a component that directs and controls the motion of one or more other components.

The hub guides the wheel in a rotational motion. The hub is the wheel’s guiding component.

Sealing prevents a fluid from flowing out of its container.

A valve prevents air from escaping from a bicycle tire. The valve is the sealing component.

Lubrication reduces friction between two components.

Applying oil to a bicycle chain reduces the friction between the components of the chain and sprocket system. Oil is the lubricating component.

• A complex mechanical function is the role fulfilled by a single component or a mechanism inside a technological system.

• A mechanism, often called a system, is a set of components that transmits or transforms motion in a technological system.

When there is motion transmission, the type of motion between the driver and driven components of a system is the same.

In a bicycle, when the crankset rotates, it drives the rear sprocket to rotate too. It is a chain and sprocket motion transmission system.

A speed change is a variation between the rotational speed of the driver component and the rotational speed of the driven component in a system.

In a bicycle, the chain and sprocket system can transmit a rotational motion with a speed change.

The speed change allows the rider to rotate the bicycle’s rear wheel with varying degrees of difficulty. The number of teeth in the wheel gears determines the gear ratio.

When there is motion transformation, the type of motion between the driver component and driven component of a system changes.

In an adjustable wrench, when the worm rotates, it drives the rectilinear translation of the mobile jaw. It is a worm and rack motion transformation system.

The driver component, also called the driving unit, transmits the motion generated by an external force to another component in order to enable the operation of the technological system.

The pedals act as the driver component. They transmit the motion generated by the driving torque from the cyclist’s legs to the rear wheel.

The intermediate component is located between the driver and driven components and sets the driven component in motion.

A chain and sprocket system acts as an intermediate component. It transmits the motion from the pedals (driver component) to the rear wheel (driven component).

After a series of transmissions or transformations of the motion from the driver and/or intermediate component(s), the driven component, also called the receiving unit, receives the final motion.

The driving torque exerted by feet pushing on the pedals (driver component) causes the crankset to rotate. This rotation is transmitted to the rear wheel (driven component) by a chain and sprocket system (intermediate component).