| Re: [GMCnet] Mech. Engineer Q. [message #106548] |
Tue, 23 November 2010 12:44  |
Gary Casey
Messages: 448
Registered: September 2009
Karma: 0
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Senior Member |
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I'm not so sure that the method discussed will accomplish the task. The
question is about the objective. I have assumed that the "best" balance is to
have equal loading on the two front wheels and take up whatever side-to-side
load differences there are with the rears. Right? What else would be better?
I'm not sure. If you initially support the rears by a single point in the
middle you will end up adjusting the fronts to absorb all side-to-side
unbalance. Frankly, I don't know of any way to make sure the fronts are equally
loaded except to use a scale. Is it important to have the fronts equally
loaded? More questions than answers.
Gary Casey
This is rather interesting. A simple beam doesn't care if it's upside-down,
except for the effect of the weight of the beam itself, which in this case
is pretty negligible.
But I would suspect that stiffness is a more important parameter than
strength. I might be tempted to design for deflection rather than allowable
loads.
So, your concept of operation is to jack up the coach, slide the fixture
under the rear bogies, align hooks in the fixture to the openings in the
bogie frames (which would serve to prevent slippage and also to ensure
centering), and lower the coach onto the fixture.
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| Re: [GMCnet] Mech. Engineer Q. [message #106549 is a reply to message #106548] |
Tue, 23 November 2010 12:55  |
emerystora
Messages: 4442
Registered: January 2004
Karma: 13
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Senior Member |
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I am beginning to think that some GMCers have way, way too much time on their hands! :)
Emery Stora
On Nov 23, 2010, at 11:44 AM, Gary Casey wrote:
> I'm not so sure that the method discussed will accomplish the task. The
> question is about the objective. I have assumed that the "best" balance is to
> have equal loading on the two front wheels and take up whatever side-to-side
> load differences there are with the rears. Right? What else would be better?
> I'm not sure. If you initially support the rears by a single point in the
> middle you will end up adjusting the fronts to absorb all side-to-side
> unbalance. Frankly, I don't know of any way to make sure the fronts are equally
> loaded except to use a scale. Is it important to have the fronts equally
> loaded? More questions than answers.
> Gary Casey
>
>
> This is rather interesting. A simple beam doesn't care if it's upside-down,
> except for the effect of the weight of the beam itself, which in this case
> is pretty negligible.
>
> But I would suspect that stiffness is a more important parameter than
> strength. I might be tempted to design for deflection rather than allowable
> loads.
>
> So, your concept of operation is to jack up the coach, slide the fixture
> under the rear bogies, align hooks in the fixture to the openings in the
> bogie frames (which would serve to prevent slippage and also to ensure
> centering), and lower the coach onto the fixture.
>
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| Re: [GMCnet] Mech. Engineer Q. [message #106557 is a reply to message #106548] |
Tue, 23 November 2010 13:21 |
g.winger
Messages: 792
Registered: February 2008
Location: Warrenton,Missouri
Karma: 0
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Emery,,, when the line is runnin good (no brakdowns),,, I think. Maybe should stop thinkin????,,,, PL
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