I had a look at these a while ago. I found a rather nice old example that was used in France for collecting Myrtille (Vaccinium myrtillus - Billberry/ Blueberry etc) which can be found here;
PEIGNE À MYRTILLES - (BLUEBERRY COMB)
The side view does not seemt o work on the English page but it is seen when you put the cursor over the picture in detail on the French version here
http://museum.agropolis.fr/pages/expos/aliments/fruits_legumes/objets/peigne.htm#
It was the nearest thing I came to for an idea of how to construct one outdoors as it is made of wood, including the teeth (some metal used on the back presumably to help it last longer)
You use them literally to 'comb' the blueberry bushes, collecting the berries into a basket. The same method is still used but more often now with metal toothed ones like in Scandinavia.
The web page has some details of dimensions which may help. Looking at the image it appears the teeth are formed by cutting a series of parallel slots into a piece of wood, presumably ;with the grain' and using a hardwood. I imagine you could use a similar technique with a piece of bone such as a deer scapula perhaps which may be a bit more resilient.
It is a tradition that is continued in the Montagne Ardéchoise (Ardeche Mountain )region in the S of France, where they have an association dedicated to gathering myrtle. They have a nice graphic which shows the technique for gathering:
And a series of detail photos here;
http://www.myrtille-ardeche.com/page30.php3?lang=fr
Including this close-up of the comb in action;
http://www.myrtille-ardeche.com/
It would be interesting to find out other techniques and utensils that used to be used for gathering other forms of fruits, berries and nuts. For instance, I can't see the comb working so well with blackberries
And there must be some way to reach those big juicy ones always up high and out of reach