This would be the traditional playground swing with two or more swings hanging from a single straight bar. The clever bit is that there would be a control at the side to adjust the rigidity of the bar (it could, for example be a steel cable with adjustable tension instead of a bar).

Making this support more flexible would increase the swings' tendency to swing in synchronisation with each other and increase the amount of energy a gently swinging swing will sap from one swinging with a greater amplitude. This would be useful when you have one child who can't swing on their own but needs to be pushed. This swing would allow you to put them on a swing next to a child who can swing really well, turn up the "coupled oscillation" dial and let the the swing of the child who can't swing on their own be driven by that of the other child.
-- hippo, Jul 23 2007

Odd sympathy http://en.wikipedia.org/wiki/Odd_sympathy
Interesting story about coupled oscillation [hippo, Jul 23 2007]

Bifilar Pendulum http://brunelleschi...arie/ependolo2.html
for those who wish to know more about pendulum actions [xenzag, Jul 24 2007]

Swong Swong
Uses clockwork to drive slaved swings. [phoenix, Jul 26 2007]

Very half-baked. + for you.
-- globaltourniquet, Jul 23 2007


This odd sympathy swing (really a sort of antipathy, since the pendulums always wind up opposite) could be accomplished by mounting the bar holding the swings to a pair of horizontal heavy steel truck suspension springs used elsewhere in the playground to support horses and other rides.

There is no need for a dial or control, which I fear would be jammed with sand or otherwise broken. A determined swinger could overpower the springs and swing as she sees fit. A passive swinger will swing according to impetus from the bar.

The only thing about these spring-mounted swings is that they would need to be higher off the ground than a usual swing. This is not an issue for the kids who need to be pushed, since often they must be helped up to high swings anyway. However, hard and heavy swingers could lower the bar so that a swingers feet are closer to the ground on the downswing than they thought., and they might whack into the ground.

Now I am thinking about hard and heavy swingers. Again.
-- bungston, Jul 23 2007


I hear there are specialist websites for that sort of thing, [bungston].
-- hippo, Jul 24 2007


Anything that perpetuates the myth of being able to go over the bar whilst raising the probabilty of catching your fingers in something is fine by me.
-- marklar, Jul 24 2007


Where I live, I'm sure the local spides would find a way of using this to launch empty Buckfast bottles at passing cars. (+)
-- xenzag, Jul 24 2007


I think this is a brilliant idea, [hippo]. [++]
-- MaxwellBuchanan, Jul 24 2007


Thanks [Max]!
-- hippo, Dec 31 2017


This method could be used to construct a bandpass filter by making the two swings of slightly different lengths and then fine-tuning the coupling between them, like tuning tank circuits in old analogue radios.

I have no idea why anyone might want to do this.
-- Wrongfellow, Dec 31 2017


If each swing was attached to its own axle, and the two were almost butted up against each other, you could use a rough clutch mechanism - two discs at the ends of the axles which are pressed together when coupling is desired.

To harvest the torque and transfer it, the swings would have to have rigid bars rather than chains or ropes to hold the occupants.

Great idea :)
-- imagin8or, Jun 16 2020



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