I'm not sure these even exist but if they do does anyone know where to
get them?

I want hinges for a flap that I can fit to a shelf front edge that can
hinge down to let you get stuff off the shelf (the easy bit) but that
when you raise the flap into the vertical position it will stay upright
and prevent items on the shelf (in my van) being thrown off when I go
round corners. (It's not so practicable to fit a catch above the shelf to
hold the flap.)

I hope the ascii-art shows the principle: the part of the hinge attached
to the flap has an elongated hole so in the vertically up position the
flap drops slightly and locks in position. When you lift the flap it is
then able to rotate on the hinge-pin and drop into the open position.


|| - flap
||
||__
--------- || \
| || 0 | - hinge pin
shelf | || | - hinge with slot able to slide up/down pin
| \_/
---------

--
John Stumbles

Extreme moderate