Some ideas we've had (and please, feel free to expand on these):
A collapsing platen that folds like origami:
Rob wrote: Brainstorming about a foldable platen... say the platen is all 1/4" acrylic (as mine will be, once the damn stuff comes in the mail -- apparently Weld-On acrylic glue has to ship ground, because the vapors make airplanes dizzy). Instead of welding the acrylic together, suppose you stack the two pieces of acrylic, one on top of the other (i.e. you take your 2 pieces of 11" x 15" x 1/4" and stack them to make 11" x 15" x 1/2"). I'd draw a diagram, but at ASCII art I am teh sux0rz.
Now, along one edge, glue a long strip of flexible yet strong material, forming a long hinge. Maybe a strip of cloth from an old pair of jeans, or some kind of rubber or plastic. Something that won't fall apart after being folded and unfolded hundreds of times, and something that won't let one plate move much with respect to the other plate.
I think the only reason I like 1/4" because it's big enough not to require precision work. I suppose the thing could be made of 1/8" with a 1/4" wide strip hinge.
Next, something is needed to hold the plates rigidly at 90 degrees when unfolded. What if we split the 6" x 6" diamond pieces down the middle, and added strip hinges everywhere. Then, it could fold flat, and when unfolded, maybe a bar across the hinge could prevent the diamonds from folding back up.
Or maybe use more bolts and wingnuts to hold the whole contraption rigid somehow.
Oka has some ideas as well, I think his idea of not using the frame is pretty interesting:Daniel wrote:I see what you're saying. I've had similar thoughts, but it seems to ... hinge... on the hinge.
My first thought was simply to use a flat piece of metal in place of the current gussets. Ignoring thickness for a moment, imagine screws portruding from the person-facing side of the platen (the cut faces of the acrylic along the 11" edges). You'd simply have a metal bracket (or two) that bolted onto that side, like a gusset that went on the facing edges of the acrylic.
The problem with that kind of approach is that the platen bends in the middle. Before I learned to glue acrylic, I made two platens that weren't glued along the bottom edge. They both bowed and it caused lots of problems. Your hinge might help -- and I love the collapsible nature of it -- but I suspect we'd need something rigid.
Another approach is to use glass. Glass is nice and rigid (and thin -- my 1/4" platen sometimes wouldn't let me see into the gutters of books, so I made the 1/8" one). One could make a simple, flat thing in the shape of a gusset with a slot for each pane of glass. It could be made of a slab of plastic or wood. Not as elegant as your folding idea, but more rigid and just as flat-packable. I've attached a real-world drawing to communicate my idea a bit better. "GST" is "gusset-shaped thing".
I have some other ideas for making the base vastly smaller as well as making the UST or VST flat-packable. If you used linear bearings like drawer slides it could get super-small and be a single piece of wood with an angle cut in it to support the bookholder/cradle.
Oka wrote:I think to make portable book scanner, we can use hinges on the botom of book holder, and put the lock so the book holder is always on 90degre if we open it.. the thinner miter box and small rails, knock down counter top material the PVC pipe may be can help.and we can put the miter box on the table and not using frame. the challenge is the portable book scanner must be put in the 20"X20"X5" cardbox, and for light we can use LED and battery.