So Now You Know
Seeing the need to prevent damage to pinball machines and to prevent people from cheating to win prizes, Harry Williams invented a device to sense this movement and stop the machine's current play.
This new device was called a "Stool Pigeon" and consisted of a small metal ball resting on a non-conductive pedestal above a metal ring. Excessive nudging of the pinball machine shook the ball off the pedestal and onto the metal ring, thus completing the circuit and causing the play to end.
But the Stool Pigeon proved to be unreliable, and took too long to reset. A new way had to be found...
The Plumb Bob was first used as a Tilt Mechanism in 1935. This new design (also by Harry Williams) was far more reliable, easier to adjust, and didn't have to be reset.
The Plumb Bob Tilt works on the same principle as a construction Plumb Bob but is a metal rod attached to the pinball machine cabinet at one end (top), with the weight at the other (bottom). It has a metal ring surrounding the weighted end.
The Plumb Bob works as a switch contact. The metal rod is attached to one half of the switch wiring, while the metal ring is attached to the other half. When the Plumb Bob swings due to movement of the pinball machine, it eventually touches the metal ring, closing the circuit (switch), and tells the pinball it has been "tilted".
Harry Williams called this new version "Tilt" after he overheard some players saying that the machine had "Tilted" after nudging it too much.
This new device was called a "Stool Pigeon" and consisted of a small metal ball resting on a non-conductive pedestal above a metal ring. Excessive nudging of the pinball machine shook the ball off the pedestal and onto the metal ring, thus completing the circuit and causing the play to end.
But the Stool Pigeon proved to be unreliable, and took too long to reset. A new way had to be found...
The Plumb Bob was first used as a Tilt Mechanism in 1935. This new design (also by Harry Williams) was far more reliable, easier to adjust, and didn't have to be reset.
The Plumb Bob Tilt works on the same principle as a construction Plumb Bob but is a metal rod attached to the pinball machine cabinet at one end (top), with the weight at the other (bottom). It has a metal ring surrounding the weighted end.
The Plumb Bob works as a switch contact. The metal rod is attached to one half of the switch wiring, while the metal ring is attached to the other half. When the Plumb Bob swings due to movement of the pinball machine, it eventually touches the metal ring, closing the circuit (switch), and tells the pinball it has been "tilted".
Harry Williams called this new version "Tilt" after he overheard some players saying that the machine had "Tilted" after nudging it too much.
