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What are the calculations on the wire rope sheave? Looks to me it's
overloaded as it will see nearly 2X the wire rope tension as it's
total load.<br>
<br>
George<br>
<br>
<div class="moz-cite-prefix">On 2/22/2017 10:34 AM, Marco Mirazita
wrote:<br>
</div>
<blockquote
cite="mid:0993815e72ea3080dfd89d8fcfb8797a@webmail.lnf.infn.it"
type="cite">Hi all,
<br>
here we try to answer to the questions raised in the last couple
of days on the RICH assembly.
<br>
<br>
1) Winch load
<br>
The weight of the RICH fully assembled is about 1000 kg, including
the stiffening elements. This would be the number to be consider
if we had to lift the RICH from the floor with the winch.
<br>
Instead, we want to use the winch to rotate the RICH on top of the
assembly structure. Thus, the maximum pull force that the winch
must apply has to be calculated in this conditions. This has been
done time ago, as you can see in the two attached slides. The
resulting maximum pull force is about 7750 N, with a 25% safety
margin we reach 9700 N, that is a weight of 990 kg, lower than
1000 kg.
<br>
The procedure for the load test should be defined based on the
foreseen usage of the winch.
<br>
<br>
2) Eye bolt
<br>
We agree to use the hoist ring as suggested by George. The depth
of the threaded hole in the aluminum angular element of the RICH
is 50 mm. The bolt is screwed to the RICH passing through the bar
of the stiffening element, which is 10 mm thick, 15 mm if we
consider also the washers. We need to screw the M24 bolt at least
for a depth of 35 mm in order to have a grade 8 connection. Thus
the bolt should be at least 35+15=50 mm.
<br>
If JLab can provide them, it would be great.
<br>
<br>
3) Assembly structure
<br>
We thank DSG to have volunteered to continue the assembly of the
structures. We agree that the early completion of the assembly
will save time for the many other tasks we have to do, so please
go on. We suggest you to perform a preliminary planarity check of
the base plates before mounting the vertical posts. A final
alignment check of the structure can be done when Dario and Sandro
will be at JLab on march 6, and then you can proceed together with
the assembly of the rotation elements. Please don't hesitate to
contact us in case of doubts or troubles.
<br>
<br>
4) Documentation
<br>
We are preparing the documentation for the assembly procedure of
the electronic panel support. We will also include the description
of the mechanical assembly of the boards on the panel.
<br>
The assembly of the mirrors will not be done before few months. In
addition, we planned in the next weeks a test of the assembly of
the aerogel on the planar mirrors. The results of these tests may
impact the procedure of the mirror assembly, thus we will work on
the procedure documentation after these tests.
<br>
For the electronics tests, it is up to the electronic group.
<br>
<br>
Dario, Marco, Sandro, Vincenzo
<br>
<br>
<fieldset class="mimeAttachmentHeader"></fieldset>
<br>
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</pre>
</blockquote>
<br>
<pre class="moz-signature" cols="72">--
George Jacobs
Jefferson Lab (TJNAF)
STE 12
12000 Jefferson Ave.
Newport News, VA 23606
(office) 757-269-7115
(cell) 757-876-0480
(email) <a class="moz-txt-link-abbreviated" href="mailto:jacobsg@jlab.org">jacobsg@jlab.org</a>
(website) <a class="moz-txt-link-freetext" href="https://userweb.jlab.org/~jacobsg">https://userweb.jlab.org/~jacobsg</a></pre>
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