An expandable round table that remains round

We used to have a circular dining table that was expandable in that you could separate the two halves and insert an extra leaf in the middle. The extra leaf was rectangular shaped which meant that the expanded table was no longer circular.

Seamus Bellamy points me to this expandable circular table that remains circular. Pretty cool and clever. It would have helped King Arthur as the number of his knights fluctuated.


  1. flex says

    I wonder how often the gearing needs to be cleaned of dust?

    I’ve occasionally played with clever furniture at garage sales or consignment shops, some with pretty intricate gearing. I regularly find that the thin oil used on the gearing has collected dust over the years and then starts to seize as the dust absorbs the oil and the system dries out. Simple hinges are not all the bad, there are a lot of sewing machine tables with hinges and cables. But on occasion I find a sewing machine table with gearing, and they are often bound up and hard to move. They can be cleaned pretty easily, but for something like a geared television stand or table, unless you have a regular preventive maintenance schedule, you typically don’t find there is a problem until you need to use it. At that point you don’t have the 2 hours needed to clean and re-oil the device.

    I do admire the engineering and the precision in building such devices. They are neat.

  2. Dr Sarah says

    These remind me of those sci-fi animations where the hero’s car suddely opens out/extends in numerous directions to turn into the Supermobile or whatever.

  3. Jo Seyton says

    It cannot be circular -- the radius of the 6 circular arcs do not change, but the radius of the entire table does. Also, the leaves that fold out appear to be straight, rather than arcs themselves.

    Also -- there appears to be a problem with the login-function. WordPress does nothing at all, the G+ button opens a window and then stops, the other G opens a window and says no servers are available, fortunately the Yahoo button works.

  4. Mano Singham says

    Good point, that the expanded table cannot be a true circle. So that means that there is a limit to much it can be made bigger while retaining the illusion of circularity.

  5. DonDueed says

    Roj’s compilation seems to be about evenly divided between small round tables that expand into larger, not-quite-round shapes, and large round tables that collapse into smaller, not-quite-round shapes.

    Some of the latter looked like they had an outer ring that rose up to trim the smaller shape into a true circle. With that addition you do have a size-shifting round table.

    On the other hand, it seems to me that in many actual dining rooms, it would be preferable to have the simpler shape-shifter: small round to larger oval, as Mano described.

  6. Johnny Vector says

    Flex @#4 says

    I regularly find that the thin oil used on the gearing has collected dust over the years and then starts to seize as the dust absorbs the oil and the system dries out.

    Just what I was thinking. Probably what you want to do is coat all the gearing with Braycote 601EF. That’s pretty much the standard lubricant for space applications, and it doesn’t dry out even after years under hard vacuum. Eventually it may get filled with dust, but as a grease it probably doesn’t matter too much.

    Probably doubles the cost of the table, but it should make the gearing last for decades.

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