Branson 4720Ch Drawbar strength

[LouNY]

I don't recall ever seeing a spec for drawbar tongue weight for any of the US Bransons. While yours may be higher then average
I wouldn't think it to be over weight.

 

[RjCorazza]

Hey Cougsfan, you're always the first to reply to my post! I was pulling an RC2512 land pride, rated for 40 to 100 horse power. It broke right where it meets the housing, you can see the grains of the metal where it sheared. It did bend a little before it broke, then suddenly I heard a loud pop, it bent my hydraulic remotes and ripped the hydraulic cable in the process. The tongue weight on mower says 793lbs and the mower is ~2500lbs. It was mowing and pulling extremely well until that point, but the terrain is a bit rough.

Different manufacturers, but the Kubota L60 series list a tongue weight of 1430 lbs, and either 5500 lbs trailer or 6600 lbs for the 4760-6060.
I can't imagine your machine is that much different, and well within it's designed abilities. TTWT on YouTube did a video on using a (too large) mower that discussed the length of the drawbar that you may want to view.

 

[Slowpoke Slim]

I've pulled some pretty hard pulls with mine. Much harder than you can possibly be pulling on that batwing mower with. But they have all been more or less linear pulls (as in straight or mostly straight in line with the bar). I suspect that what actually broke the bar was either a twisting or a shearing force pressing on it from the top or sides. Could have been a metal weakness, or could have been some odd angle that the hitch bound up in and something had to give. Luckily it was the draw bar itself and not the pto gearbox in the tractor.

I have been looking very closely at the RhinoAg TS10 and TS12 for my own application, and they specifically caution about turning the mower too tightly when making turns. It loads the hitch but it also loads the pto shaft. We're talking side loading here, which can be destructive.

 

[ceaster]

I've pulled some pretty hard pulls with mine. Much harder than you can possibly be pulling on that batwing mower with. But they have all been more or less linear pulls (as in straight or mostly straight in line with the bar). I suspect that what actually broke the bar was either a twisting or a shearing force pressing on it from the top or sides. Could have been a metal weakness, or could have been some odd angle that the hitch bound up in and something had to give. Luckily it was the draw bar itself and not the pto gearbox in the tractor.

I have been looking very closely at the RhinoAg TS10 and TS12 for my own application, and they specifically caution about turning the mower too tightly when making turns. It loads the hitch but it also loads the pto shaft. We're talking side loading here, which can be destructive.

I was definitely pulling through some rugged terrain, in areas, there are a lot of little holes the tractor dips into along the way where the skids would dig into some dirt and make the tractor lug a little, but nothing that would out right stop the tractor. The mower specifies not to make more than an 80 degree, turn, which I've tried to avoid, usually the tightest is just mowing around trees. I figured I would have heard some PTO noise if I turned too tight, but I'm not sure.

 

[ceaster]

Different manufacturers, but the Kubota L60 series list a tongue weight of 1430 lbs, and either 5500 lbs trailer or 6600 lbs for the 4760-6060.
I can't imagine your machine is that much different, and well within it's designed abilities. TTWT on YouTube did a video on using a (too large) mower that discussed the length of the drawbar that you may want to view.

Those are good specs, I appreciate having something to generalize with. I did see that TTWT video, his problem was because he didn't extend the drawbar out 14" inches from what I remember, so the PTO travels too far into the case.

 

[oldnslo]

I have broken 3 or 4 draw bars from excessive tongue weight but never broke one on straight pull. Tongue weight was from a 180 bushel manure spreader on 70 JD diesel so suspect a whole lot more than your bush hog. Bouncing was what fatigued and broke them.

 

[ceaster]

Thanks for the replies. After getting back to my tractor and examining it, it looks like as called out in this thread, the weak point is at the hitch pin hole that comes out right at the carriage where the 14 inch clearance is required.

 

[YanmarFever]

I have a 5520 cab and I pull a 2910 bush hog mower, its 10' wide and I make real sharp turns all the time because I mow a large grove.
I hope I never have that happen, but I do turn real slow at the ends...

 

[oldnslo]

Their appears to be some strange grain structure in the steel on the left side. Is that from being cracked for a period of time or a possible defect - imperfection in the steel?

I ended up making length of log chain that connected to the 3PH lift arms that supports the draw bar when 3PH is fully raised. This prevented all future broken draw bars. Do the same thing today with 1100 bushel grain cart on 8520 Deere.

 

[ceaster]

Their appears to be some strange grain structure in the steel on the left side. Is that from being cracked for a period of time or a possible defect - imperfection in the steel?

I ended up making length of log chain that connected to the 3PH lift arms that supports the draw bar when 3PH is fully raised. This prevented all future broken draw bars. Do the same thing today with 1100 bushel grain cart on 8520 Deere.

I think it's dirty from hyrdaulic fluid getting on it after the remote got ripped up, I was spraying everything off. Do you have a picture you could share of how you support it? I'm curious how it clears the PTO shaft when making turns.