In America there used to be a common expression (but I haven't heard it
used lately) describing something as a "Rube Goldberg Machine." This
came from cartoons by Rube Goldberg of incredibly complex ways to
accomplish something simple. Interestingly, Rube Goldberg was mainly a
political cartoonist.
See cartoon at :
http://dashboards.tv/images/rube-goldberg.jpgAlso see: article at:
http://en.wikipedia.org/wiki/Rube_Goldberg_machinegl
George Huxtable wrote:
> Hanno included 3 attachments with his last message, but without accompanying
> text.
>
> First, as a general request, can I ask that when contributors provide
> pointers or links for us to look at, a few words are added to the email text
> to say what's likely to be found there, so only those with an interest will
> be bothered to look.
>
> In my case, Hanno's attachments were rather rewarding. I found three
> diagrams from patent no 1912358 of 1929, by Vannevar Bush, a name that
> Americans of a
certain age may well recognise. It can be readily located,
> from that number, within Google Patents. The patent referred to the use of a
> mirror as an artificial horizon, and a proposal for stabilising it against
> accelerations. It included several pages of text, omitted by Hanno, without
> which those diagrams would make little sense.
>
> An amazing proposal, which I greatly doubt could ever have been constructed.
> It shows a horizontal mirror suspended on springs within a liquid-filled
> transparent sphere, that floated on a bath of mercury within another
> transparent sphere. Clearly, the author relished complication. It put me in
> mind of those Eastern cosmologies in which the Earth was held by a comely
> maiden, who stood on the back of an elephant, which was then supported by
> the shell of a giant turtle, which swam in the ocean, and so on, combined
>
with the concentric crystal spheres that carry the planets in the Ptolemaic
> universe. All with the idea of decoupling the mirror from the accelerations
> that it was being subjected to.
>
> Not for the faint-hearted to attempt constructing, then. It seems to have
> got no further, which is unsurprising.
>
> George.
>
> contact George Huxtable, at
george@hux.me.uk> or at +44 1865 820222 (from UK, 01865 820222)
> or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.
> ----- Original Message -----
> From: "Hanno Ix" <
hannoix@sbcglobal.net>
> To: <
navlist@fer3.com>
>
Sent: Tuesday, August 18, 2009 4:57 AM
> Subject: [NavList 9559] Re: The development of bubble sextants
>
>
> Gentlemen:
>
> Please refer to:
>
> US Patent 1,912,358
> V. Bush: Apparatus for establishing an artificial datum
> Filed April 8, 1928
>
> The inventor means an artificial horizon. Please refer to the attachments
> for the drawings.
>
> He has implemented a mechanical lowpass filter. We have discussed LP's
> before. Better yet: This filter simultaneously works in 2 coordinates, roll
> and pitch.
>
> He also points out that the natural oscillating frequency of the mirror
> should be as "low as possible" but he doesn't give any data. Since the roll
> frequency of ships is rather low to begin with (judging from you-tube:
> about. 0.1 Hz = 1 period per 10 sec for an oil-tanker ) the filter has to
>
have a cut-off frequency of about 0.01Hz which amounts to 1 period per 100
> sec. The filter also needs to be sufficiently damped. The reason is
> simply avoiding resonant oscillations of the filter/mirror in response to
> the ship's movements. To build an LP of this kind is the challenge!
>
> The inventor has made every effort to decouple the housing of the mirror
> from the body of the sextant. So to speak, he created something like a
> bubble level floating within bubble level.
>
> With a lowpass of this kind, influences from pitch/roll would be reduced by
> a factor of 100, possibly more. So, a 10 degree roll would create 0.1 degree
> (6 arc-min) deflection of the mirror. Smaller ship will have higher
> roll/pitch frequencies than oil-tankers, maybe 0.5 Hz. Accordingly, on
> smaller ships 1 arc-min oscillation of the mirror might be possible. Is that
>
error sufficiently low given the circumstances? It is certainly much less
> than I saw once in a bubble sextant.
>
> Perhaps most importantly, this patent points out how
> to separate accelerations of the sextant which are instantaneous from
> gravitation which is constant in time.
>
> When I made my proposal with the tubular ring the other day I had similar
> ideas in mind, however I had not fully understood the interaction between
> bubble and spirit.
>
> Regards
>
>
>
>
>
>
> >
>
>
