i designed very simple and cheap devices for opening and closing cold frames that could also be adapted to opening vents in greenhouses. The devices, called CFTs, are powered by solar energy, and are more sensitive to solar radiation than to temperature. The details are at the following link:
There are also expensive commercial products such as :
A couple thoughts.
I think it should be possible, as you are suggesting Lu, to devise a removable way to mount the implement triangles. It might end up being a different technique for each implement. I like your idea for the bolt-on mounting studs. I'll bet we could design and tailor them on the spot, given an implement.
Lu, your PDF omits the plate brace near the top of the implement triangle. This triangle is probably not strong enough without it unless the triangle is solidly bolted or permanently welded to the implement. But also, it is a component of the latching mechanism pictured in the first photos. So that leads me to...
The original French PDF shows, in an inset photo on the first page, a spring loaded latch on the male/tractor side triangle that locks into the implement triangle. The drawings in the rest of the article don't show this, but instead show a bolt-on top retaining plate that keeps the two latched together. Omitting this would allow the implement to get bumped off the tractor triangle. Hitting a pothole on the street while transporting the implement could conceivably drop the implement in the street. The bolt on thingy in the drawings is a get-off-the-tractor-to-secure-it item, and looks like a part that needs a wrench and will get rusty, hassle-ish, left behind, lost. I think we could make a spring catch that would work from the tractor seat with a pull cord. Attached is a (crude) drawing of how this might be done (the drawing is upside down from the orientation it would be installed in). Could be positioned and welded on as/where needed.
I think it worth reminding people who are coming to make a triangle mount for themselves to:
Bring your target implement to the build-in. Otherwise (as Lu suggests) bring the exact dimensions, layout and spacing of the mounting points on your implement so we can plan for how you will attach the triangle to the implement when you get back to the farm.
If you are going to permanently mount the triangle on your implement you won't be able to pick up the implement without the tractor-side triangle.
Remember to note if the target tractor is category I or II (or III ?)
Decide if you want to build the sliding upper attachment to allow the implement to "float", as shown in the French PDF.
Lu: I can bring a 110v MIG (sans gas) with a small spool of flux core, a couple angle grinders ... what else would be useful? Any small bits of stock?
THanks to Emily, we have a PDF of the proposed
basic triangles using the american steel recommended by
Dorn. The gussets (plating) and the attachment brackets
are left off in this drawing, since they will be the same as
the french version, but in 2.5 " x .5" flat bar.
A single 20' piece of the c channel makes 4 implement
triangles. A single 24' piece of the square tubing
makes 3 tractor triangles.
i took the liberty of makig the bottom element
of the tractor triangle tubing instead of flat stock. This
means the open ends will need plating, but there may be
other advantages. For me, it's an advantage to use
metal that i can weld with the flux core mini MIG.
Please look at the attached drawings, suggest
changes to the design soon! In the
french document, the implement triangle is welded to the
implement, or, for the articulating implements, studs are
mounted and welded in place. Do french farms have 50 amp
outlets at the end of the rows? Would it be better for the
implement triangle to attach so that it is removable without
special tools? How will the implement triangle attach to
your implement at the bottom links? If your implement has
bolt on studs for the bottom links to engage, can we remove
the bolt on studs and just bolt the implement to brackets
welded on to the bottom of the implement triangle? What is
the distance between the corresponding brackets on your
implement (s)? The issue here is that the bottom links on
the tractor SWING in the horizontal plane, and therefore can
engage the fixed studs on the implement. On the implement
triangle, no such swinging. Therefore a set of rigid
brackets could be welded to the implement triangle at a
distance apart so they can overlap (just wider than or
narrower than) the brackets on the implement and a 1"
bolt slipped through the bracket's corresponding holes.
lups. Dorn, if you want to move this to
the farmhack discussion, please do. And please send me a
link to it so i can follow.
metal fabricators seem interested in the Build IT weekend here at the firehouse, November 9 and 10. i have yet to hear from lots of farms but i assume after the frost farmers will have time to get interested.
i am about to (this week) enlist Emily's help making a 3D model for "la version americaine" of the triangle attacher. i will use Dorn's recommendation of 2.5 " by 11g square tubing nesting in 3x4.1 c channel. Will the square tubing nest deeply enough?
i solicit any other comments about the design. For example, on the tractor triangle the bottom element (part E3) is simply a piece of thick flat stock. Should it have a web? Could it be just another piece of square tubing (same amount of steel)? Another question i have: Is the implement triangle always welded to the implement? Does the articulating implement triangle also have to be fabricated around the implement. Is there a way to make the implement triangle just bolt on or pin on so that they can be completely fabricated separate from the implements?
Also, if there is anything an american farmer knows is different on american three point hitches from french ones, we could make changes. For example, the top link to bottom link vertical distance is given as 488 mm (19 1/4") . Is that OK? Also, the hole sizes for the links and the bar sizes for the implements. Are these good? And the spacing of the link brackets, 2" for the top link and 2 5/32" for the bottoms; is that standard here?
The brackets that reach out from the tractor triangle and grab the links onthe tractor are specified as 9/16" thick. The problem here is that i was hoping to cut the holes with my plasma cutter, which can only cut up to about 3/8 inch thick. i am therefore of a mind to make all the parts with holes 3/8" strap unless someone thinks that is really to thin. i know "la robustesse de cette piece ne peut pas etre negligee blah blah blah..." If necessary the holes can be cut with a blow torch, but with my puny drill press: Jamais!. Maybe 3/8 can be used and a little gusset plated over the top between the two brackets to reinforce them...
i hope to get the design done this week. THen, find out how many we will build and order the steel. The square tubing and channel will be new metal, while the strap and plate i hope to get scrap.
i think we should be able to construct one or two sets of these in a weekend. i only have one 50 amp outlet and one stick welder. Does anyone have a mobile welder? Also, can people bring extra leathers, goggles, earphones, welding shields, gloves, welding magnets, and quick clamps?
Finally, does anyone want to help pay forthe steel, welding rod (i'm thnkgin 6013, 5/32", but open to suggestions) , and abrasive discs we will burn through! THanks! lu