Pinball flippers appear simple, but each press of the cabinet button activates a fast, carefully controlled combination of electricity, magnetism and mechanical movement. The basic design has existed for decades, although modern pinball machines use electronic control systems to make flippers more responsive, reliable and easier to diagnose.

The Main Parts of a Pinball Flipper

A typical flipper assembly contains:

• A cabinet button and electrical switch
• A flipper coil, also called a solenoid
• A steel plunger
• A crank and shaft assembly
• The visible plastic flipper bat
• An end-of-stroke, or EOS, switch
• A return spring
• Bushings, brackets and a coil stop

These parts are mounted beneath the playfield. Current manufacturer documentation continues to show the coil, EOS switch, plunger and crank, extension spring, bushing and flipper bat as separate parts of the assembly.

What Happens When You Press the Button?

In a modern pinball machine, pressing the flipper button closes a low-power cabinet switch. The machine’s control system detects that input and activates the electrical driver connected to the flipper coil.

Older electromechanical machines used more direct electrical circuits, sometimes carrying substantial current through the cabinet switches. Modern solid-state machines separate the button input from the high-power coil circuit. This reduces wear on the switch contacts and allows the game software to monitor and control the flipper.

Stern’s modern SPIKE architecture, for example, identifies the left and right flipper buttons as cabinet switch inputs while listing the flipper coils separately as controlled playfield drivers.

How the Coil Moves the Flipper

When the coil receives electricity, the wire winding around its sleeve creates a magnetic field. That magnetic field rapidly pulls the steel plunger into the centre of the coil.

The plunger is connected to a crank attached to the flipper shaft. As the plunger moves, the crank rotates the shaft, causing the flipper bat above the playfield to swing upwards.

The complete action happens extremely quickly:

Button press → coil energises → plunger moves → crank rotates → flipper rises

The solenoid is the complete electromagnetic actuator. The plunger and crank are the moving mechanical components; the crank itself should not be described as the solenoid.

What Does the EOS Switch Do?

Near the top of the flipper’s movement, the mechanism operates the end-of-stroke switch. The EOS switch confirms that the flipper has reached, or is approaching, the end of its intended travel.

Many conventional flipper coils contain two windings in one assembly. A powerful winding provides the initial movement, while a lower-power winding can hold the flipper in its raised position without producing as much heat. In these systems, the EOS circuit helps remove the full-power winding after the initial stroke.

Modern electronically controlled systems may also use the EOS switch as an input to the control board. The electronics can then manage the coil’s power, timing and protection. The exact method varies by manufacturer and machine generation, so the EOS switch should not simply be described as a switch that “turns on a second coil.” Most dual-wound flipper coils are one physical coil containing two separate windings.

How the Flipper Returns to Rest

When the player releases the button, the control system stops powering the coil. The magnetic field collapses, allowing the plunger to move out of the coil.

An extension spring then pulls the mechanism back to its resting position, rotating the flipper bat downwards and preparing it for the next shot.

The return spring is important. Gravity alone does not reliably return a flipper, especially because the assembly must reset quickly and consistently during fast gameplay.

How a Flipper Controls the Ball

The flipper transfers energy to the ball through the rotating bat and its rubber ring. The result depends on more than raw coil strength. Important factors include:

• The speed of the flipper bat
• Where the ball contacts the bat
• The angle of contact
• The condition and grip of the flipper rubber
• Coil selection and operating voltage
• Plunger, bushing and linkage condition
• Software-controlled pulse timing

A shot near the tip of the flipper usually sends the ball faster and farther because that part of the bat travels through a greater distance during the rotation. Contact closer to the base produces a shorter, more controlled movement.

For this reason, assigning one universal force figure to every pinball flipper is misleading. Flipper performance varies considerably between machines, coil types, playfield designs and mechanical conditions.

Why Pinball Flippers Become Weak

A weak flipper is not always caused by a defective coil. Common causes include a worn plunger or coil stop, a damaged coil sleeve, loose crank hardware, excessive movement in the flipper bushing, an incorrectly adjusted EOS switch, worn flipper rubber or problems with the machine’s power and driver circuits.

Regular inspection is especially important on commercial machines because thousands of rapid movements gradually wear the metal and plastic components.

When Were Pinball Flippers Invented?

Gottlieb’s Humpty Dumpty, released in 1947, is widely recognised as the first commercially produced pinball machine with player-controlled electromechanical flippers. It used six relatively small flippers positioned around the playfield. Designer Harry Mabs is generally credited with creating the flipper mechanism used in the game. 

The familiar arrangement of two powerful flippers near the bottom of the playfield developed during the following years and became the standard design associated with modern pinball.

Alt Çizgi

Pinball flippers work by converting electrical energy into magnetic force and then into rapid mechanical rotation. Pressing the button activates a coil, the coil pulls a plunger, and the plunger turns the crank and flipper shaft. An EOS switch helps the machine manage the end of the stroke, while a return spring resets the flipper when the button is released.

Modern electronics have improved the way flippers are controlled, but the essential electromagnetic mechanism remains one of pinball’s most durable and effective engineering designs.