Looking for Slack Rope Switch for Hoist

[eeJason]

I'm working on a project that employs a monorail hoist for lifting and positioning 55 gal drums. One of the requirements for the hoist is that it include a "slack rope detection system." The hoist manufacturer that I'm working with isn't familiar with such a device, and several hours of internet searching have been fruitless.

Clearly I could just put a load cell at the end of the rope, but that seems like overkill since all I need is a switch that tells me "drum present" or "drum absent." Could anybody provide me with some leads / sources for such a device, or provide some ideas for how I could detect slack on a hoist?

Thanks!

 

[FOETS]

Hoisting in mining has several systems.
The one I remember puts a sensor on the attachment to the conveyance and transmits an RF signal up the hoist rope using loop coils. It alarmed if the attachment laid over to some degree from vertical. This was some years back so there are probably other concepts and systems available now.
In mining the reason for putting the sensor at the conveyance is the length of wind and relative weight of the hoist rope would make it difficult to detect early enough at the drum through load monitoring. Your situation may be simpler than this.
Some leads for you to try; though these would probably be also overkill and expensive for your application but may give some ideas

Becker Mining Systems
Siemag
ABB
Levelock
The IEEE has quite a few papers on the subject related to mining and if you are a member there may be some leads there.

Descending and jamming in the guides is typically the problem allowing the rope to pile on top of the conveyance, until it breaks free. I dont understand what you mean by "drum present" as the drum could be present and you could still have a slack rope condition.

Good Hunting


FOETS
The truth is out there. Anyone know the URL?