Mechanics of a pull up bar.

[Ikea desk]

Good afternoon everyone,

 

I am posting a question about pull up bars, sorry it is a bit long-winded.

 

I have a 'powerbar' which is this:

http://www.ukfitnesssupplies.co.uk/products-Powerbar-Doorway-Chin-Up-Bar_POWERBAR.htm

 

However the spring mechanisms in the folding arms are broken (No big deal) and the 2 prongs which secure the bar on the opposite side of the door exert too much pressure onto my (landlord's) doorframe causing damage. The cantilever method seems to work well though, and the bar you hang from is above the height of the door, which gives you more hanging space.

 

I have looked into this, the 'iron gym':

http://www.saunabelt.co.uk/iron-gym-pull-up-bar-p-154.html?zenid=b6eebaedced2a9173dd448920571dac4

 

which uses a long bar to secure to the doorframe (which is better than 2 prongs as the force is distributed over a wider area), but the bar you hang from rests directly against the side of the door frame. (There is one extra bar on the powerbar sticking up and out)

 

With the powerbar the instructions said to hang from the part which is away from the door and hence force is distibuted into the frame as well as from the prongs, however the iron gym bar is effectively the lower bar on the powerbar. - If that makes sense.

 

I want a cross between both bars, the powerbar cantilever effect, but the iron gym support bar rather than prongs.

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My question is: What proportion of my weight will pull down on the doorframe using the iron gym compared to the powerbar?

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I will see if I can get some dimensions, I don't need an exact answer, just a rough figure which will enable me to decide wether or not an iron gym will damage my doorframe.

 

Alternatively if anyone knows of a pull up bar which will suit my needs then that may save some calculation!

 

Thankyou for reading this and any answers will be appreciated.

[swansont]

So the second system has a bar which sits atop the door frame? The picture isn't clear. It looks like all your weight is on the trim for the iron gym. The power bar has your weight pressing against the wall; you could alleviate the problem by mounting a steel plate where the prongs go, to reduce the pressure.

[Ikea desk]

Hi Swansont

 

Thanks for your reply, I can't make modifications to the door frame, but do you mean a steal plate on the powerbar where the prongs are? Bear in mind the prong arms move and can fold back to make the whole bar flat (for storage/carriage)

 

Here is a picture which might show the iron gym better

http://www.my3cents.com/review_images/iron_gym.jpg

[iNow]

Why don't you just give it four legs to divert the weight to the floor... Much like a suspension bridge? Then the door frame acts to offer lateral stability, but is less of a factor as per supporting your weight.

[Ikea desk]

Yes that sounds good, although I may as well build a standalone pull up bar if I need legs which are taller than me. Which I am now thinking about...

[swansont]

Hi Swansont

 

Thanks for your reply, I can't make modifications to the door frame, but do you mean a steal plate on the powerbar where the prongs are? Bear in mind the prong arms move and can fold back to make the whole bar flat (for storage/carriage)

 

Here is a picture which might show the iron gym better

http://www.my3cents.com/review_images/iron_gym.jpg

 

Yeah, that's what I was thinking of.