tag:blogger.com,1999:blog-7577633936396294153.post1697375813268186411..comments2024-03-28T15:18:58.434-05:00Comments on Industrial History: Crane WrecksDennis DeBrulerhttp://www.blogger.com/profile/13992361354510209661noreply@blogger.comBlogger3125tag:blogger.com,1999:blog-7577633936396294153.post-77782408133129593282019-09-26T19:17:43.356-05:002019-09-26T19:17:43.356-05:00Thanks for the clarification of a "4-way.&quo...Thanks for the clarification of a "4-way." I have fixed the comment.Dennis DeBrulerhttps://www.blogger.com/profile/13992361354510209661noreply@blogger.comtag:blogger.com,1999:blog-7577633936396294153.post-85552023190059331522019-09-26T19:12:35.463-05:002019-09-26T19:12:35.463-05:00I'm really confused because I have taken photo...I'm really confused because I have taken photos and/or video of operators putting their luffer into a jackknife position at the end of the work day. And if I visit the sites off hours, the crane is jackknifed. I've posted photos and video for a Microsoft expansion: https://industrialscenery.blogspot.com/2019/04/catching-mlc300-crane-at-microsoft-in.html Photos and video for a 21000 are on my todo list. I've also seen a luffer that was working in Joliet being jackknifed at quitting time.Dennis DeBrulerhttps://www.blogger.com/profile/13992361354510209661noreply@blogger.comtag:blogger.com,1999:blog-7577633936396294153.post-62967580405172386652019-09-26T08:10:49.625-05:002019-09-26T08:10:49.625-05:00Regarding your repeated comments on "jackknif...Regarding your repeated comments on "jackknife" procedures for luffing jib lattice booms parking/high winds. The jackknife position is the weakest position to leave a crane, and most manufacturers explicitly warn of doing so. Manitowoc recommends only leaving in this position if guy lines are attached 2 on each side tethered to at least 30,000 lb per line. Other manufacturers only have a park position for the boom/luffer combination or boom and jib flat on the ground. Boom combinations in jackknife position is extremely susceptible to side winds. Leaving a crane in jackknife position is WRONG, and the practice is the product of the ignorant repeating the advice of others who are equally ignorant. <br /><br />Also to clarify from another note regarding four-ways as a multi-sheave load block; 4-ways are four-leg rigging spreaders, usually attached to a ring. NOT a load block.<br /> I hope this helps to clarify these issues. - Corkey CraneAnonymoushttps://www.blogger.com/profile/11009316784576458693noreply@blogger.com