Cellist’s Board
23/10/2017
When playing on a parquet floor, which is quite common, cellists or double bassists use a "board" to secure their spike without damaging the floor.
This one is innovative:
On the left, the board has multiple holes to accommodate the spike; nothing unusual, not even the shape, which vaguely resembles a guitar. However, this one is digitally milled from precious, highly durable exotic wood. The underside is coated with an anti-slip varnish.
On the right, a small leather tab ensures the cord doesn’t slip under the chair leg. Incidentally, the cord is a synthetic fiber typically used to replace steel cables on racing sailboats; it’s exceptionally strong, lightweight, and has near-zero stretch (high modulus), ensuring stable adjustments.
The main innovation lies in the center:
This device, invented for this project, allows continuous and precise adjustment. It slides easily when handled and locks automatically under the slightest tension.
Its principle is illustrated in the following figure:
The cord is attached to the lever with a simple loop, allowing easy removal, for example, to wrap around a piano stool leg.
The entire assembly is 3D-printed, enabling an internal axis fixed to the outer casing while keeping the moving part in place. The same principle could use a removable axis, like a nut, to close two casing faces around the internal part.
The result is simply stunning.