Branson 4720Ch Drawbar strength

[ceaster]

Does anyone know how much you can pull with the drawbars on the 4720Ch or the alike chassis? I couldn't find any specs listed. I broke mine, pulling a mower and I wanted to know if it's a fluke or if I'm overloading it.

 

[Cougsfan]

I am curious, exactly how and where did yours break, and what kind of mower were you pulling? I have pulled extremely hard with mine (all the tractor will do) without issues.

 

[ceaster]

I am curious, exactly how and where did yours break, and what kind of mower were you pulling? I have pulled extremely hard with mine (all the tractor will do) without issues.

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.

 

[Cougsfan]

Hmm, I lead a sheltered life. That is the first rotary mower I have seen pulled by the drawbar as opposed to the three point. If it bent some before it broke it must have had some fairly severe shear or twisting loads along with the expected tensile load. Maybe it was a batch of bad metal, or just an unfortunate circumstance.

I would guess the drawbar could be welded back together and reinforced by welding plate or angle irons to the sides over the break. It would help to anneal it after welding. If yours is like mine, the drawbar has several holes for the pin and you can just use the next hole if you are not at the end. I would make sure the mower has room to twist or rotate sideways without twisting the drawbar. Might require modifying the attachment point.

 

[ceaster]

Hmm, I lead a sheltered life. That is the first rotary mower I have seen pulled by the drawbar as opposed to the three point. If it bent some before it broke it must have had some fairly severe shear or twisting loads along with the expected tensile load. Maybe it was a batch of bad metal, or just an unfortunate circumstance.

I would guess the drawbar could be welded back together and reinforced by welding plate or angle irons to the sides over the break. It would help to anneal it after welding. If yours is like mine, the drawbar has several holes for the pin and you can just use the next hole if you are not at the end. I would make sure the mower has room to twist or rotate sideways without twisting the drawbar. Might require modifying the attachment point.

It's a Land Pride RC2512 pull type, it has a single hydraulic cable that raises the deck and folds the wings. I thought about reinforcing the drawbar, but my fear is if it's not a defective one and I make the drawbar stronger then something on the tractor housing would break instead. You have to keep the drawbar out 14 inches from the end of the PTO or you can cause a catastrophic failure when making turns or sloping too much by pushing the PTO shaft into the rear housing, I suppose that's that weakness is having to extend it out so far too.

Branson doesn't have any specs posted on how much it can handle, and although this mower is designed for lower horse power requirements for the size, the weight may still be too much. Just wish I knew.

Thanks as always

 

[ericm979]

Did it break at one of the holes for the retaining pin?

I have not looked under there to see how it's held on the tractor but when its out far enough to prevent PTO damage, is it less well supported by the tractor?

 

[ptsg]

Ceaster, I think it's safe to assume that you're well within limits on your tractor and mower setup.

I can't give you actual numbers for that model in particular because it was never sold here in Europe, but using mine as an example, which is equivalent to the 3515R in the US, it has a 7700 lbs braked towing capacity and 6600 lbs unbraked. The tongue weight is rated at around 1760 lbs, I assume it's all the way retracted. Now this is a smaller frame/weight/HP, so yours should get a more than mine does.

With all of this being said, the welds on the drawbar bracket on mine, doesn't really impress me that much but I've pulled a lot with it and it never came apart yet so I guess it's good enough.

 

[ceaster]

Did it break at one of the holes for the retaining pin?

I have not looked under there to see how it's held on the tractor but when its out far enough to prevent PTO damage, is it less well supported by the tractor?

It sheared exactly where the housing quits supporting the draw bare directly, so right where it sticks out from the holder.

 

[ceaster]

Ceaster, I think it's safe to assume that you're well within limits on your tractor and mower setup.

I can't give you actual numbers for that model in particular because it was never sold here in Europe, but using mine as an example, which is equivalent to the 3515R in the US, it has a 7700 lbs braked towing capacity and 6600 lbs unbraked. The tongue weight is rated at around 1760 lbs, I assume it's all the way retracted. Now this is a smaller frame/weight/HP, so yours should get a more than mine does.

With all of this being said, the welds on the drawbar bracket on mine, doesn't really impress me that much but I've pulled a lot with it and it never came apart yet so I guess it's good enough.

Thanks for letting me know. The dealer did say they'd replace it under warranty, and that i'm probably pushing it too hard, but that there are plenty of people out there using these low HP batwings without a problem.

 

[ceaster]

I'll try posting a some pictures when I get home if that's helpful.

 

[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.