<html><body><div style="font-family: tahoma,new york,times,serif; font-size: 14pt; color: #009900"><div>hi george,<br></div><div>my understanding is that a 7x19 cable is used.<br data-mce-bogus="1"></div><div>the breaking load for this cable, as per the manual, is 5559 Kg, much greater than 2x the tension (1550 Kg)<br data-mce-bogus="1"></div><div>amrit<br data-mce-bogus="1"></div><div><img class="shrinkToFit" alt="http://www.bergencable.com/technology/images/7x19str.jpg" src="http://www.bergencable.com/technology/images/7x19str.jpg" data-mce-src="http://www.bergencable.com/technology/images/7x19str.jpg" height="398" width="498"></div><div><br data-mce-bogus="1"></div><div><br></div><hr id="zwchr" data-marker="__DIVIDER__"><div data-marker="__HEADERS__"><b>From: </b>"George Jacobs" <jacobsg@jlab.org><br><b>To: </b>"Marco Mirazita" <Marco.Mirazita@lnf.infn.it>, "Tyler Lemon" <tlemon@jlab.org><br><b>Cc: </b>"dsg-rich" <dsg-rich@jlab.org>, "Bob Miller" <rmiller@jlab.org><br><b>Sent: </b>Monday, February 27, 2017 1:33:59 PM<br><b>Subject: </b>Re: [Dsg-rich] RICH assembly<br></div><div><br></div><div data-marker="__QUOTED_TEXT__">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">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><pre>_______________________________________________
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</pre></blockquote><br><pre class="moz-signature">--
George Jacobs
Jefferson Lab (TJNAF)
STE 12
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