Replies

1. 
   4DThinker | Jun 24, 2003 10:42pm | #1

   I'd never heard of the JUPE tables.  But after reading your post I looked up some pictures.

   It looks like the wedge shaped 1/8 circle sections slide out from the center, making room for the dart shaped inserts to go between these.  So each need so be somehow tracked.  I can image using accuride under-drawer sliding drawer guides for a modern approach.

   To mechanise them to all slide out at the same time when the top is rotated, you'll need to create an 8-tracked center disk with spiral tracks to trap a pin from each wedge. As you rotate the top relative to it's base, the pins could climb "up" the spiral, sliding the wedges out.  Rotate it the other way, and the wedges would slide back in. There will need to be some framing or interlocking to support the dart sections as they are put in place. Perhaps the wedges could be over-extended, darts set in place, then the wedges closed down a bit to trap the darts.

   I'm just guessing, of course.  But if you think about how you want the top to perform, it's not too hard to imagine a mechanism to allow that performance.

   4DThinker

1. 
   Jamie_Buxton | Jun 25, 2003 01:31am | #2

   The wedge-shaped sections form the entire periphery in the small size, and part of the periphery in the large size.  This means that the table can be a true circle in either the small size or the large size, but not in both. 

   Someplace I've seen an expandable circular table that is a true circle in both sizes.  I think it used supports that slide radially out from under the table top, and leaves that sit on them.   Like the Jupe tables, the leaves store elsewhere.

1. 
   4DThinker | Jun 25, 2003 07:12am | #3

   If you've seen a round expandable table that is a true circle no matter what size it is, then the design must have a variable arc rim.  If that's possible, I'd sure love to see how it is done.

   4DThinker

1. 
   Jamie_Buxton | Jun 25, 2003 08:02am | #4

   4D --

     No, that was my point: the Jupe table can't be round in both positions.

     The table design I was trying to describe is sketched in the attachment.  Maybe it isn't as cute as the mechanisms in the Jupe table, but it is easier to build.  It also is round in both sizes.  

        Jamie

   
1. 
   4DThinker | Jun 25, 2003 05:25pm | #5

   Ahhhh.  Amazing what a good sketch can communicate.  But I think expanding a table by adding a ring around it is sorta cheating.  It would be simpler to just make a larger diameter circle top from parallel sections that would store easily, then assemble them OVER the smaller round top.

   I'm still intrigued by the idea, though.  I've thought of all sorts of ways to expand rectangular table tops, but circular or oval is clearly gonna take some advanced thinking. 

   4DThinker

2. 
   Jamie_Buxton | Jun 25, 2003 08:48pm | #6

   4D -

     I can think of three arguments against the long overlay leaves you suggest.  The strongest is storage space: you have to store a complete table top, instead of storing only the expansion area.   The second is esthetic: the long straight leaves don't follow the circular theme of the table, while the leaves in my sketch do.  The third is table height: overlay leaves will change the height by 3/4" or so.   Me, I notice that much -- it can feel like being a kid again, when the table top was at chin level.

     As to expanding the table top the way you and I both want to do, I haven't given up yet.  Here's an approach that gives some encouragement.   Start with a hexagonal table made from six equilateral triangles.   The table's small position is with all the triangles meeting in the center.   To get a larger table, slide all the triangles radially, while rotating them.  You can keep the seams between triangles tight, and a hexagonal hole opens in the middle of the table.   The expansion leaf would fill that hole.  Heck, perhaps it could rise from underneath, driven by the same Juke-like mechanism that controls the triangles' movements.  The trouble with this simple table is that the periphery of the expanded table is not hexagonal, but kinda star-shaped.  However, I have the feeling that something could be done to disguise that awkwardness.  I also haven't investigated using more triangles to make the table, or using curved seams between the segments.  

             Jamie

3. 
   4DThinker | Jun 25, 2003 09:58pm | #7

   Well, the added complete top could be composed of larger wedge sections instead of parallel cut sections.  They could exactly match the look of the smaller top, except of course with a bigger radius.  Of course you'd need a wedge shaped place to store them when not needed.  Done right, the wedges could simply fold up, perhaps a half top (four sections) at a time.

   As for adding height to the table,  I had a student make once make a rectangular table that would fold open to double it's area.  She and I came up with a simple way to drop the base 3/4" to keep the expanded table top at the same height as the folded top.  The top would rotate 90 degrees when open to stay centered over the base.  When it rotated, it would wedge the legs up 3/4". Rotate it back, and the legs would move down.  The legs traveled in sliding dovetail slots from two directions.  Held tightly, but loose enough to move up and down.

    4DThinker

4. 
   wmgran | Jun 26, 2003 02:48am | #8

   I think the table in question is demonstrated on http://www.smith-watson.com/radial.html or http://www.rauantiques.com/moreinfo.asp?InventoryID=40789&InvCategoryID=15

   The question is whether the rotating mechanism can be purchased or if there are plans fro such a mechanism.

5. 
   Jamie_Buxton | Jun 26, 2003 03:23am | #9

   That antique table is worth $350,000??!!!      WOW!

   Another avenue for plans might be the Jupe patent itself.   If it is like modern US patents, it should describe the Jupe mechanism quite clearly.

2. 
   nigelUsa | Jun 26, 2003 05:23am | #10

   Take a look at this link http://www.fletcherfletcher.com/fletcher_expanding/expanding.htm

   there is a "movie" showing the table working.