The Idea     6 prototypes     Development     Production
Inventor of the Double Trolley, Marc Grue, explains:

"In the beginning, I had to learn how to weld steel tubes to put the prototypes together. Using my first hand knowledge as a bass player, combined with my newly learnt engineering skills, I was able to assess which details needed improvement - for example one screw would hit a narrow door frame, one edge was too sharp when you lifted the bass into the bus, and a lock mechanism needed to be redesigned.

The Double Trolley is the culmination of all of these experiences and improvements."
Working on the 4th prototype
The final prototype was drawn from scratch on a computer incorporating the lessons learnt from all of the previous prototypes.

Engineer Henning Forbech from Techvision helped to make proportions and technical details of the whole construction before it went into production.
Marc Grue with engineer Henning Forbech making computer drawings of every part of the Double Trolley for the production process.


I got the Double Trolley and it works very well! It is built more firmly and so easier to move the instrument and to sit on than I thought. Among all, I'm surprised at that it can make sharp turns so I can move the instrument in narrow space like a corridor in my home. All of my colleagues admired it, and some of them said they would like to buy it.

Today, when I took this picture, there was a slight strong earthquake, but my instrument which was standing with the trolley didn't fall down!

Yosuke Yamazoe

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