Are available in either single or double versions and also with neon indication built in.

Slide 2 shows the operation for this type of switch which is controlled by a ball rolling across a contact strip as the rocker switch is toggled from one position to the other, this action then transfers the circuit from the normally open condition to the normally closed condition.

Several designs are available, from single contacts to double contacts and also some switches that only make the circuit whilst you hold the button in, but the underlying working principle is the same in all designs.

As you push the button in, a set of contact is broken and another set of contact become made, changing the flow of the circuit.

Rotary switches are larger than the rest of the switches shown here, due to the requirements to switch greater power that is required to run the full machine, they may also be able to switch not only single phase electricity but also 3 phase.

Operation wise, no circuit flows until the knob on the switch is rotated from the off to the on position, some machines will also employ a 2 stage rotary switch, the first stage only switches power to the control circuits, while the second position switches power through for the machines heating element.

Inside an espresso machine this type of switch will mainly be found on the smaller design pressure switches (slide 3). 

Whilst outside the machine itself you will find this type employed a lot in your coffee grinder to detect if the grounds hopper is full.