IF you are interested in hearing how I would do the re-enforcement, here goes...
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this supports the blade itself. This is the strongback. Dont have to be super heavy duty. Its the added depth that gives strength. 1/8" plate would be sufficient. Or could use a piece of 5" channel iron or something and then cut the triangles for top and bottom.
This is how I would strengthen the A-frame:
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Box in the underside of the horizontal. This will increase the strength in the horizontal (pulling direction) significantly. And also prevent bees.
The gussets will help prevent bending in the vertical direction like it has already been bent.
This is what I would do if the blade were mine. Materials to be used and design of it would all be dependent on what I have in the scrap pile. But even if you had to buy new steel, AND have it cut/sheared to your dimensions (triangles and such) I dont see it being more than $100 worth. And this would significantly strengthen the blade. The only last weak link would be the pivot pin diameter, and the category 1 hitch set-up. But I dont think any of that would be a big issue.
Also, if it has not been done, one other thing I would do...that triangular box u-shape piece where the TL hooks up....that entire vertical section, if it isnt welded solid to the main beam...I would do so.
Again, this is just what I would do if it were mine. It would take maybe half a day at most with just a set of torches and a welder and digging through the scrap pile. But YMMV as always.