Electromagnetic locks: how much force can a human pull?

Ideas and instructions how you can make your own bondage toys.
Post Reply
pancakes
*
Posts: 2
Joined: 11 Jan 2017, 22:55

Electromagnetic locks: how much force can a human pull?

Post by pancakes »

I am considering a setup with electromagnetic locks. Since I don't trust key release and finding that while bound my plan is to use direct electromagnetic locks, one connected to each hand or if the hands are bound together having them daisy chained.

To keep the setup safe they will be battery power and controlled by a normally closed relay on a RPI together with at least 1 mechanical timer. I am considering an emergency release using a rope tied to my hand tied to the top of a bottle with some nasty liquid and then on the other side is connected to one of the poles of the battery so I can pull it off with a consequence.

So first, how much force can a human pull? I am considering either a 180kg or 280 kg version. The 180 kg version is much lighter but if it's to weak then it's no point buying it. A pulleysystem could for example double the force required but that feels over complicated and requires more space.

Is there any other considerations with this setup?
Last edited by Sir Cumference on 12 Jan 2017, 18:11, edited 1 time in total.
Reason: Headline
OrgasmAlley
****
Posts: 515
Joined: 18 Nov 2012, 17:43

Re: Electromagnetic locks: how much force can a human pull?

Post by OrgasmAlley »

First, I assume you meant a NO (normally open) relay, such that when not powered the relay is not closed, and does not provide power to the device.

Your question is impossible to answer, because it is highly dependent upon the person and position involved. How strong is the restrained individual? Which muscles are they using, and with how much leverage? Something as simple as curling the arm can vary by several times depending on the amount of extension at the start of the movement. If you can employ the body's larger muscles, a person can generate quite a lot of force. Also, can you "get a run at it", employing momentum to assist?

Another major consideration is the direction of force relative to the plane of the magnet. Door lock magnets are most strong (and tested for their rating) when the pull is straight out from the contact flat. Sliding force is less than the rated strength.

In general, the 600# (280 kg) version is substantially more useful IMX.
pancakes
*
Posts: 2
Joined: 11 Jan 2017, 22:55

Re: Electromagnetic locks: how much force can a human pull?

Post by pancakes »

Yes of course, and would of course test everything several times over and measure the current being fed at which time before I do anything. Was simply thinking about a closed circuit when typing it down.

To counteract that I will of course put on sides for the magnets so they can't slide off. How much a difference do you imagine that would make?
OrgasmAlley
****
Posts: 515
Joined: 18 Nov 2012, 17:43

Re: Electromagnetic locks: how much force can a human pull?

Post by OrgasmAlley »

Honestly, the thing to do is construct your setup so the pull is perpendicular to the plane of the magnet face. I would strongly suggest that your arrangement be one in which the strike plate physically falls away from the magnet upon release, out of the range in which it can be recaptured in the event of a breif loss and immediate resumption of power.
lj
Moderator
Posts: 2255
Joined: 14 Oct 2008, 18:22
Location: East Anglia, UK

Re: Electromagnetic locks: how much force can a human pull?

Post by lj »

Bear in mind that the metal plate used as the removable part of the lock is a substantial chunk of metal and when it separates under tension, or even gravity, it could cause some damage to you or your environment. This would be particularly dangerous if the plate was overhead, and arms go numb quite quickly if held high and would be useless to prevent the plate falling in an unwanted direction (like your head!)
be a switch, double the fun :-)
User avatar
Sir Cumference
Moderator
Posts: 1606
Joined: 29 Jan 2012, 22:00
Location: Scandinavia

Re: Electromagnetic locks: how much force can a human pull?

Post by Sir Cumference »

A smaller magnet and a fulcrum-like release could be a better alternative.
~ Leatherworking, blacksmithing , woodworking and programming are the most pervertable skills you can learn! ~
OrgasmAlley
****
Posts: 515
Joined: 18 Nov 2012, 17:43

Re: Electromagnetic locks: how much force can a human pull?

Post by OrgasmAlley »

First, I certainly agree that the strike plate will hurt if it hits you, whether coming from above or swinging at you on a rope. More powerful electromagnet door locks will have heavier strike plates, too. I would not recommend an electromagnet for an overhead, anyway.

I'm not sure what advantages one finds in a smaller electromagnet. The basic versions from China are all cheap, so it's not money. The 600# version draws less than 0.5A @12VDC, so it's not power consumption. It clearly holds loads _less_ than the rated strength, so larger is more versatile from that perspective. It is a little larger and heavier... but I can't personally image those two differences justifying the added complexity of a leverage system to increase the electromagnet's strength, vs. simply getting a strong-enough unit in the first place.

In general, an average person cannot pull the strike plate straight out from a 600# electromagnet to the point of detachment. Maybe if they are able to use the strength of both legs in the attempt, but doubtful. In a number of circumstances, I suspect the average person can pull off the plate of a 350# magnet, but generally not using a single limb. The average person will be able to pull the plate from a 130# electromagnet much of the time, even using a single limb.
lehmann
*
Posts: 8
Joined: 27 Jan 2017, 16:39

Re: Electromagnetic locks: how much force can a human pull?

Post by lehmann »

I find this interesting. How / where do you plan to install the locks? Did you proceed in the meantime by any chance?
Post Reply