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Not being of an engineering background, I was first inclined to think that a door closer would reduce horizontal load on all hinges and not contribute any support in the vertical dimension.

However, bearing rotational mechanics in mind, is this necessarily true?

I think, on any normal door:

  1. The upper hinge would be under horizontal tension.
  2. The lower hinge would be under horizontal compression.

If a concealed door closer (similar to the model in the lower image) is installed into the frame below the center of mass of the door, would it exacerbate load on the hinges rather than protect them?

enter image description here

Concealed door closer, mounted in the jamb, providing constant spring-loaded compressive force.

enter image description here

Would it contribute anything to the vertical load on the hinges?

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The tension and compression on the hinges are door mass, times half of door width ,B divided by the distance of upper and lower hinges, D.

$$ m*(B/2)/D $$ And each hinge shares m/3 as shear with the middle hinge having no horizontal force.

Say concealed door closure is installed at x distance below the center hinge and applies a force F, so you have F*x = sum of the reaction of the three hinges. which is allocated most to lowers hinge and least to upper one.

Now you add or subtract this reaction to the original hinge load.

remember if you have too much out-of-plane force at the swing of the door you want to account for that too.

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    $\begingroup$ This is only true for an idealized door which is hung perfectly. In real life the tolerances are such that each hinge has to be capable of supporting the complete weight, plus the additional forces created by the door bending when the hinges are not perfectly aligned. From a practical point of view, any extra force from the door closer is just another "random change" to the redundant load paths. $\endgroup$ – alephzero Jul 28 '19 at 19:04

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