Talk:Crane (machine)

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Could someone add a section on how steam cranes work and where the largest ones are and what there lifting capacity is?

Could someone explain how cranes harness mechanical advantage?

A crane is a collection of simple machines, including inclined plane, wheel and axle, lever, pulley, wedge and screw. Perhaps someone will expand this article to explain how cranes work. Meanwhile, see mechanical advantage for more information. --Heron 18:31, 12 July 2005 (UTC)

Contents 1 Number 2 Fabrication of a Crane 3 Truck 4 Whistle communication 5 Loader Crane 6 Famous crane operators 6.1 Paul Kenneth Vikra 7 Hammerhead Crane 8 Crane Design 9 lewis irons? lifting tongs? 10 Wrecking Ball 11 Mechanical Advantage

[edit] Number

Does anyone know how many cranes there are in the world? In some places that are under development I see an awful lot of them and wonder what percentage of the world's supply is in my field of vision. CoolGuy 22:31, 1 January 2006 (UTC)

[edit] Fabrication of a Crane

I work as a "Project Management" officer & I would like more about fabrication of cranes, WBS (Work Breakdown Structure) and so on.

[edit] Truck

A crane mounted in a truck to move breaked down vehicles to the garage is called a "..."?. See image http://www.gruascorsa.com.mx/gruasremolque/

What you link to could be called a "wrecker" in the US. although I think the type you link to would be a stretch to classify as a crane as there is no vertical lift involved. The "tow truck" design would probably be considered a type of mobile crane. Although I've heard the names interchanged.--J Clear 17:58, 11 June 2006 (UTC)

[edit] Whistle communication

I am sitting in my office, and there are people with cranes doing work on another building, but they seem to be using whistles (like sport referees' whistles) to communicate. Could someone investigate that?

I Googled on "whistle coummnication crane", then on "whistle hoist". Here is what appears to be a California statue on hand-, electrical-, and audiable-hoist signals:
http://www.dir.ca.gov/title8/1605_21.html
Subchapter 4. Construction Safety Orders
Article 14. Construction Hoists
§1605.21. Introduction.

"(c) Audible Signals.

Audible signals shall not be used when there are surrounding noises of the same, or nearly the same, frequency and octave level. Signals given by means of a whistle, bell, horn, or other audible means are as follows:

(1) Hoist: Two short blasts or gongs.

(2) Lower: Three short blasts or gongs.

(3) Slow: Four long blasts or gongs.

(4) Stop: One short blast or gong.

(5) Emergency Stop: Series of short blasts or gongs.

(6) Dog Off Load: One long blast or gong. "

While you're next to the scene, you're asking us to Google? The virtual world is catching up way too fast for me. BoH 01:00, 31 August 2006 (UTC)

[edit] Loader Crane

Almost invariably called a "Hiab" by its' operators, this is a hydraulically-powered articulated arm fitted to a trailer, used to move goods onto or off of the trailer.

Perhaps this is true in Europe, but I am unfamiliar with the term in the United States.

Never heard of that either, and I live in Denmark and work in a company with several loader crane trucks... By the way, cranes from Palfinger, Fassi and 3-4 other names that I don't remember are quite common in DK, so maybe Hiab and HMF shouldn't stand alone as examples? G®iffen 16:00, 28 September 2006 (UTC)

[edit] Famous crane operators

[edit] Paul Kenneth Vikra

"The very first crane operator ( North sea) who actually managed to put an stand by vessel on pipedeck. During this incident the only casulty was an unfortunate seagal. " moved from article by: Gregorydavid 14:34, 27 May 2006 (UTC)

[edit] Hammerhead Crane

Hammerhead or Giant Cantilever Crane. Good PD photo here. Is this worth it's own section or is it a sub type of the tower crane? It seems to predate the tower crane. Perhaps both hammerhead and tower are types of Cantilever. Anyway I'm far from a crane expert/historian, so I'll leave it to those to sort out. There is an unlinked mention of one in Philadelphia Naval Shipyard that ought to link here.--J Clear 17:48, 11 June 2006 (UTC)

It is an amazing photo showing what appears to be a number of heavy artillery barrels being lifted simultaneously. It looks like an extreme heavy duty tower crane with horisontal boom and crawler with large counter weight mounted on large tower with slewing beaings. Gregorydavid 18:15, 16 August 2006 (UTC)

[edit] Crane Design

I am interested in detailed engineering design of plate box girder used as a crane girder.

=Rajendra Sawant, email : rajsawant@mtnl.net.in

Please include the statics involved in the cranes design.

[edit] lewis irons? lifting tongs?

The terms lewis irons and lifting tongs are used in the article, but I could not find any explanation for what these are. 「ѕʀʟ·✎」

see Chain-linked Lewis

Gregorydavid 15:26, 19 November 2006 (UTC)

Thanks! Also thanks for fixing the link in the article. Note that the terms "lewis irons" doesn't appear in the Chain-linked Lewis article, should it? Should it link back to Crane (machine)? 「ѕʀʟ·✎」

[edit] Wrecking Ball

Should this be added to the list. I know they are not used, but it is still a crane. Is it? Thanks, CarpD 11/25/06

[edit] Mechanical Advantage

The text states:

The lever. A balance crane contains a horizontal beam (the lever) pivoted about a point called the fulcrum. The principle of the lever allows a heavy load attached to the shorter end of the beam to be lifted by a smaller force applied in the opposite direction to the longer end of the beam. The ratio of the load's weight to the applied force is equal to the ratio of the lengths of the longer arm and the shorter arm, and is called the mechanical advantage.

While the principle of leverage is correct, its application in the modern balance crane is not. The short end of the crane is where the counterweight is located, and the load is lifted by the long end. The mechanical advantage of leverage would go to the load.

I agree. The article doesn't mention any crane type that has the load attached to a shorter arm and force applied to a longer arm. The "lever" list item under "Mechanical principles" thus seems misleading. I also think this problem is what the first poster above ("Could someone explain how cranes harness mechanical advantage?") was referring to. - Mglg 23:02, 4 June 2006 (UTC)

The counterweight at the short end of the beam is to help balance the crane as a whole.

Each crane has a load diagram that indicates what load can be lifted. In the case of a crane with a long horisontal beam the permissible load decreases with increasing distance of the hook from the tower. The actually lifting capacity of the crane motor and gear train is where the mechanical advantage comes in. The force in the cable at the hook is very high, but the force in the cable on the pulley that the motor feels is low. The machanical advantage is that the weak motor can pick up the load on the hook. To do this the pulley on the motor has to pull a realtively long piece of cable while the load just lifts off the ground. Gregorydavid 06:58, 5 June 2006 (UTC)

Yes of course. But here we are talking about the entry "the lever", and specifically the statement that "The principle of the lever allows a heavy load attached to the shorter end of the beam to be lifted by a smaller force applied in the opposite direction to the longer end of the beam." This function of levers, while true, does not seem to apply to any part of a crane, and the "lever" entry should therefore be removed from the article. --mglg_(talk) 20:10, 30 August 2006 (UTC)