| Author |
Message |
dakeb
Guest
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 Posted:
Thu May 05, 2005 4:10 pm Post subject:
mechanism problem |
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Imagine three rectangular plates with a hole in each end. They are joined
together end-to-end in a triple linkage. Component 2 is pinned to component
1, and component 3 is pinned to component 2 thus:-
-o-o-
How can I ensure component 3 is always parallel to component 1? thus:-
-o
\
o-
If I orient one of the surfaces of component 1 with one of the surfaces of
component 3 it no longer drags, because that would join three components and
you are only allowed to join them in pairs.
Thanks,
Dave
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David Janes
Guest
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| Posted:
Fri May 06, 2005 6:59 am Post subject:
Re: mechanism problem |
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First of all, if this is as you describe, NOTHING moves, much less something
staying parallel to something else. Can you go to 'Applications>Mechanism', pick
the drag hand and make this thing move. If you can't make it move, it'll always be
parallel, i.e., a straight line. On the other hand, if you put a pivot point in
the middle of component two....
--
David Janes
| Quote: | "dakeb" <david.bower@uk.thalesssssssspamgroup.com> wrote
Imagine three rectangular plates with a hole in each end. They are joined
together end-to-end in a triple linkage. Component 2 is pinned to component
1, and component 3 is pinned to component 2 thus:-
-o-o-
How can I ensure component 3 is always parallel to component 1? thus:-
-o
\
o-
If I orient one of the surfaces of component 1 with one of the surfaces of
component 3 it no longer drags, because that would join three components and
you are only allowed to join them in pairs.
Thanks,
Dave
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| Back to top |
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dakeb
Guest
|
| Posted:
Mon May 09, 2005 3:35 pm Post subject:
Re: mechanism problem |
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It's like three links of a chain starting off in a straight line. Dragging
link 3 moves it out of parallel with link 1.
"David Janes" <djanes@cox.net.involllix> wrote in message
news:kMIee.11450$tQ.1653@fed1read06...
| Quote: | First of all, if this is as you describe, NOTHING moves, much less
something
staying parallel to something else. Can you go to
'Applications>Mechanism', pick
the drag hand and make this thing move. If you can't make it move, it'll
always be
parallel, i.e., a straight line. On the other hand, if you put a pivot
point in
the middle of component two....
--
David Janes
"dakeb" <david.bower@uk.thalesssssssspamgroup.com> wrote
Imagine three rectangular plates with a hole in each end. They are
joined
together end-to-end in a triple linkage. Component 2 is pinned to
component
1, and component 3 is pinned to component 2 thus:-
-o-o-
How can I ensure component 3 is always parallel to component 1? thus:-
-o
\
o-
If I orient one of the surfaces of component 1 with one of the surfaces
of
component 3 it no longer drags, because that would join three components
and
you are only allowed to join them in pairs.
Thanks,
Dave
|
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| Back to top |
|
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David Janes
Guest
|
| Posted:
Mon May 09, 2005 4:10 pm Post subject:
Re: mechanism problem |
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|
If you set this up so that the middle link pivots and the outer links pivot and
slide (so that the pivot point can move), you should be able to produce the motion
where the left end goes down and the right end goes up, the two staying parallel.
On the other hand, if they are indeed three chain links, no pivot points except
their connections to each other, I see no reason for the end link to move at all
when the first is moved.
--
David Janes
| Quote: | "dakeb" <david.bower@uk.thalesssssssspamgroup.com> wrote
It's like three links of a chain starting off in a straight line. Dragging
link 3 moves it out of parallel with link 1.
"David Janes" <djanes@cox.net.involllix> wrote in message
news:kMIee.11450$tQ.1653@fed1read06...
First of all, if this is as you describe, NOTHING moves, much less
something
staying parallel to something else. Can you go to
'Applications>Mechanism', pick
the drag hand and make this thing move. If you can't make it move, it'll
always be
parallel, i.e., a straight line. On the other hand, if you put a pivot
point in
the middle of component two....
--
David Janes
"dakeb" <david.bower@uk.thalesssssssspamgroup.com> wrote
Imagine three rectangular plates with a hole in each end. They are
joined
together end-to-end in a triple linkage. Component 2 is pinned to
component
1, and component 3 is pinned to component 2 thus:-
-o-o-
How can I ensure component 3 is always parallel to component 1? thus:-
-o
\
o-
If I orient one of the surfaces of component 1 with one of the surfaces
of
component 3 it no longer drags, because that would join three components
and
you are only allowed to join them in pairs.
Thanks,
Dave
|
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| Back to top |
|
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dakeb
Guest
|
| Posted:
Mon May 09, 2005 4:10 pm Post subject:
Re: mechanism problem |
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|
No, I simplified the application.
In reality, the 'links' are a three-part cable arm. The first link is pinned
to the back of a sliding tray, so it can swivel and move as the tray is
withdrawn. The third link is pinned to the rear of the rack, so it can also
swivel. The second (centre) link can effectively move anywhere in 2d space
between the first and third links, and adopt any angle.
T o constrain the centre link, I hoped to force the centre link to remain
normal to the back of the tray.
"David Janes" <djanes@cox.net.involllix> wrote in message
news:MnIfe.14569$tQ.10496@fed1read06...
| Quote: | If you set this up so that the middle link pivots and the outer links
pivot and
slide (so that the pivot point can move), you should be able to produce
the motion
where the left end goes down and the right end goes up, the two staying
parallel.
On the other hand, if they are indeed three chain links, no pivot points
except
their connections to each other, I see no reason for the end link to move
at all
when the first is moved.
--
David Janes
"dakeb" <david.bower@uk.thalesssssssspamgroup.com> wrote
It's like three links of a chain starting off in a straight line.
Dragging
link 3 moves it out of parallel with link 1.
"David Janes" <djanes@cox.net.involllix> wrote in message
news:kMIee.11450$tQ.1653@fed1read06...
First of all, if this is as you describe, NOTHING moves, much less
something
staying parallel to something else. Can you go to
'Applications>Mechanism', pick
the drag hand and make this thing move. If you can't make it move,
it'll
always be
parallel, i.e., a straight line. On the other hand, if you put a pivot
point in
the middle of component two....
--
David Janes
"dakeb" <david.bower@uk.thalesssssssspamgroup.com> wrote
Imagine three rectangular plates with a hole in each end. They are
joined
together end-to-end in a triple linkage. Component 2 is pinned to
component
1, and component 3 is pinned to component 2 thus:-
-o-o-
How can I ensure component 3 is always parallel to component 1?
thus:-
-o
\
o-
If I orient one of the surfaces of component 1 with one of the
surfaces
of
component 3 it no longer drags, because that would join three
components
and
you are only allowed to join them in pairs.
Thanks,
Dave
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