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Posted (edited)

Hi.

In need to lift 700Kg to the place an item will be installed, I have been looking for a winch. A couple of salespersons said the winches they sell are rated for 2000Kg; which fits safety margins but are not meant for lifting vertically, just pulling horizontally with such force. I do not get it. What am I missing, what am I not considering as why the winch force cannot be used for lifting ?

 

[The industry uses hoists for the same task, but chain length limitations do not fit my task (35 metres height). That is why am after a (wire rope) winch]

 

Edited: added a random picture borrowed from the net as example of task:

----> http://escocomm.com/wp-content/uploads/2011/11/Lucas_Oil_Speaker_Cluster-246x300.png

Edited by Externet
Posted

Most likely their figure just doesn't meet the dynamic requirements of a swinging load, and they are giving you fair warning.

 

Just to be slightly clearer. If you suspend a 2000kg load, at rest the downward force is 19600N, and this would be the force of tension on the wire. If a force accelerates the mass during lift, you will have to vector sum the forces to get a value that is greater than the maximum rating.

 

Also think, at some point it will be required that a force will be applied that is greater than 19600N to accelerate the mass into upward motion.

Posted

I get the impression that the sellers (and makers) of the winches don't want to be responsible for anything falling (damage to the object or what/who it falls on), so they say it's approved only for horizontal pulling (trucks out of mudholes, downed trees through the forest, etc).

Posted

Rather than relying on salespeople, I would look at the winch manufacturer's published specifications. You might also contact their technical/engineering departments.

 

Also, if you will be using this in a commercial setting (i.e., on a job site) then OSHA (in the U.S.) regulations might be a problem. Finally, if this involves overhead lifting, there are even more considerations.

 

I just visited the Warn Winch site and found this:

... "Lifting, on the other hand, requires lifting dead weight into the air vertically. Therefore, a lifting/pulling product like PullzAll has some unique design features, such as a load limiter, and it does not utilize a freespool clutch." ...

 

And, they have a selection of industrial wire-rope hoists that should meet your requirements:

http://www.warn.com/industrial/winches/industrial_hoists_all.shtml

Posted (edited)

A horizontal winch doesn't need a brake. Turn it off and it isn't required to hold the load. A vertically rated system, on the other hand, IS rated to hold the load after it has stopped movement (ie, will have a brake of some sort). Alternatively, some ratchet-based horizontal systems don't have a reverse so once you get the load up, you have no safe way to lower it back down (if you're stupid enough to use it vertically).

Edited by InigoMontoya

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