Why the Pull Back Car?
FEB 2026
Darda is a German company, actually a West-German company, from the 1970's. They are really high quality and …
Apparently the cars can get up to 30 mph! I bought a few on Ebay and they go fast.
How Do We Play With This Car?
In case you forgot how these fun toys worked.
Let's Open Up the Car
There can't be that many parts, right?
For those counting at home, that's 25 parts.
There are a lot of parts. But let's focus on the Spring first.
This is a rotary spring, also known as a …. or a …. It
It's this energy that propels the car forward. When you pull back, you are winding up a spring. And when you let go, you are releasing that energy, propelling the car forward.
But what parts inside the car actually wind up the spring?
In order to wind up the spring and build up energy, two gears rotate in different directions. One rotates the outside of the spring Clockwise (CW) while the other rotates the inside of the spring Counterclockwise (CCW).
Okay, but how do these gears turn in opposite directions. Before we go there, we need to talk about gears.
Let's Talk About Gears
There are several types of gears. In this pull-back car, the only gears used are called Spur gears. They're probably the simplest kind. The teeth of the gear are cut straight and they transfer motion as they rotate about the gear's center. Gears are used to transmit power. Let's see an example.
When the smaller gear rotates a full revolution, 360°, it turns the larger gear. But the larger gear doesn't rotate 360°, only a third of that. Why? Mainly due to the difference in diameters and number of gear teeth.
Why is this useful? Well we can use this to our mechanical advantage. If we need to generate lots of torque, to, for example, wind up a stiff metal spring, then torque would be useful.
Let's explore the Gear Train of the Car
There are six unique gears living inside this toy car. They each have a purpose and work together. Let's walk through each one.
IN NORMAL MOTION
The gears behave one way when the car is moving forward or backward
WHEN PRESSED DOWN
The gears behave another way when the car is pushed down
Okay, Time To Walk Through the Mechanism
Let's walk through the pencil mechanism, step by step, to understand how it all works
Why does it click?
Let's walk through the pencil mechanism, step by step, to understand how it all works
