Why does the gap between walking pad slats matter?
The gap between the slats is not a detail you would think about until you walk on it barefoot. Then it is the only thing you think about.
Here is the problem. The slats travel over a curve at the back of the walking surface, and as they go round, the gap between them opens and closes. Standing on that transition barefoot, you feel a slight pinch. Not painful, but you notice it, and you should not notice anything.
The gap is already relatively wide at 4 to 5 mm, which is what makes it possible. So the idea was to reduce how much of it is exposed.
The new samples
I received new slat cover samples yesterday that have a slightly increased depth. Deeper cover, smaller exposed gap at the rotation. So far it seems to have worked well. At least based on my tests with the four samples they sent me.
The part that was not planned
The manufacturer told me that the dark grey was the same colour as before. But it turned out to be a bit lighter. Those are the light grey ones in the photo.
Now I have sent some of the old ones back to China as colour references. You cannot believe how complicated that is. It took me two hours to prepare that parcel.
It will take a few days until the samples arrive in China, and then some more time for them to match and test the colours.
What this does to the colour plan
We basically have the same problem with the side elements, where the dark brown was too dark. They will prepare and send samples of different tones of brown, but that will take time obviously.
So I am thinking about whether we should start with the light version instead of the dark brown. I just have to check if the other parts can be made in light colours first as well.
Why a gap is harder than it looks
Every manual walking pad with slats has this problem, not just ours. The walking surface is not one continuous belt. It is a row of individual slats on a chain, and they have to move independently to travel round the curve. That means a gap, and the gap has to be wide enough for the slats to move and narrow enough that nothing catches in it.
There is a safety standard involved too. The gap between slats at the rotation points cannot exceed 8 mm. The test lab confirmed that when they looked at the design. So there is a ceiling as well as a floor, and the useful range in between is narrow.
The thing nobody tells you is how long a change like this takes. It is a new injection mould, sample rounds of roughly two weeks each, and a colour that has to be matched by eye against a physical reference that travels to another continent and back. A one millimetre change to a plastic cover is two months of calendar time.
That is the part I did not appreciate before doing this.