The Idea     6 prototypes     Development     Production
The 6 prototypes
In 1994 the first Double Trolley prototype was made.

For the next 5 years, the Double Trolley was tested by him and many other bass players to find out how to improve every detail of the concept.

In 1999 the last prototype was finished. The Double Trolley had undergone several changes and was now ready to go into production. Have a look at the history of the prototypes:
Prototype no. 1

Made of square steel tubes, this first construction is the basic concept of the Double Trolley as it is today.

The wheel part had no strap attached to it nor locking mechanism on the wheel axle to hold the rear leg of the stool piece.

Prototype no. 2

All dimensions where adjusted on this prototype, and it was made of round tubes. The bigger wheels were selected so that the trolley could roll more easily on the street and up/down stairs.

Main improvements:
  • Bigger wheels
  • Round tubes
  • Hook strap for the endpin
  • Improved stability of stool


Prototype no. 3

The height is now adjusted by a click mechanism to avoid the uncertainty of the tightening screws on the prototype no. 2.

Main improvements:
  • Click mechanism for locking the height and angle of the stool
  • Thick seat


Prototype no. 4

To give better support for the side of the bass, the seat was turned around in the trolley configuration.

Main improvements:
  • Click mechanism hidden inside the tube
  • The seat turned around to better support the bass


Prototype no. 5

The first model in aluminium reduced the overall weight of the Double Trolley.

Main improvements:
  • Lighter aluminium frame


Prototype no. 6

The first prototype built by professional craftsmen. Only small adjustments were made to this prototype before the Double Trolley was put into production.

Main improvements:
  • Computer designed
  • Solid locking mechanisms
  • Seat lock
  • Special fittings between all moving parts



My Double Trolley arrived three days after I placed my order - great service!

I immediately took my bass for a walk through the cobblestone streets around my home, and the performance was very impressive - easy one-handed pushing and an amazingly smooth ride for the bass. Used as a stool, it's simply perfect.

David Moss

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