CajunRider
Platinum Member
I would like to put in a hydraulic top link for my DK45. What's the correct size and type of cylinder? I'm thinking 3"x10"x1.25' (18.25" - 28.25").
Thanks for your help
Thanks for your help
DK45 Hydraulic Top Link
- Thread starter CajunRider
- Start date
gladehound
Veteran Member
All I can offer is that a 3 inch cylindar is big!
Assuming 2500 psi system pressure, 2500x3.14x1.5^2 = 17,600 pounds of force. I think it is overkill. Don't know if you would be at risk of breaking anything.
Assuming 2500 psi system pressure, 2500x3.14x1.5^2 = 17,600 pounds of force. I think it is overkill. Don't know if you would be at risk of breaking anything.
gladehound
Veteran Member
Thinking about this more... you just want to tilt an implement without snapping it in two, or bending it in half, in the event that you tilt too far, come to the end of your 3 pt float travel and lift the back of the tractor off the ground.
With a DK45, you have a ~2500-2600 pound 3pt lift capacity 24 inches behind the links. I would match that so that you can tilt anything you can lift. If the verticle distance between lower 2 links of the 3 pt and the upper one is 24", then you need a cylindar that can generate 2500 pounds of force. If you have 2500 psi operating pressure (just a guess). You need 1 square inch of surface area on your cylinder. To get this you need a 1.13 inch cylinder. You could go with a 1.5 inch cylinder to be sure in case you have lower system pressure or impliments with shorter vertical distances between the upper and lower links.
Let's say you have lower system pressure and less verticle distance between the upper and lower attachment points. The 1.5 inch cylinder, you get 2600 pounds of tilt 2 feet behind the links if the verticle distance between upper and lower links is 18 inches and the system pressure is 2000 psi.
Now if you want to make a big 3 pt hook to lift just about anything huge with, you could use that 3 inch cylindar, fill your bucket with weight and lift until the front is sky high, the 3pt breaks, or the tractor breaks in half. This is probably what I would do. But the 1.5 inch cylinder is probably the more sensible choice.
With a DK45, you have a ~2500-2600 pound 3pt lift capacity 24 inches behind the links. I would match that so that you can tilt anything you can lift. If the verticle distance between lower 2 links of the 3 pt and the upper one is 24", then you need a cylindar that can generate 2500 pounds of force. If you have 2500 psi operating pressure (just a guess). You need 1 square inch of surface area on your cylinder. To get this you need a 1.13 inch cylinder. You could go with a 1.5 inch cylinder to be sure in case you have lower system pressure or impliments with shorter vertical distances between the upper and lower links.
Let's say you have lower system pressure and less verticle distance between the upper and lower attachment points. The 1.5 inch cylinder, you get 2600 pounds of tilt 2 feet behind the links if the verticle distance between upper and lower links is 18 inches and the system pressure is 2000 psi.
Now if you want to make a big 3 pt hook to lift just about anything huge with, you could use that 3 inch cylindar, fill your bucket with weight and lift until the front is sky high, the 3pt breaks, or the tractor breaks in half. This is probably what I would do. But the 1.5 inch cylinder is probably the more sensible choice.
kentrodngun
Gold Member
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- Kioti LK3054 & DitchWitch R40 Trencher/Backhoe
gladehound said:
Made my day Gladehound although I've been doing free taxes for the elderly all week, so I'm easily amused PAB_OH
Platinum Member
gladehound said:
Some random thoughts, I'm getting tired sitting here in the hotel room...
What about the rod diameter. You have to be able to handle all the force the 3PH will see through dynamic loading. And if you have a 1" diameter rod then you reduce your piston area by that amount on the return stroke.
Most of the top link cylinders I see are 2"+ diameter. I'm betting it has to due with the required rod diameter to handle loading and the effective area you're left with to lift whatever implement you have hanging of the back.
gladehound
Veteran Member
Good point. I didn't think about the fact that when a cylinder pulls it has less surface area for the pressure to push against due to the rod. So you do have to go bigger to get the required lift. Thanks for the correction. Shock is another consideration.
A 1 inch rod reduces surface area by 0.79 square inches. So a 1.5" cylinder with a 1" rod would exert 1.77 x system pressure on the push stroke but only 0.98 x system pressure on the pull stroke. So with 2000 psi you get about 2000 pounds of pull.
The list below gives an idea of how much weight you will be able to tilt up with different cylinders at a distance behind the links that equals the distance between the link attachment points. This doesn't take changing angles into acount and assumes a right angle between the cylinder and a line drawn through the link attachment points. In reality, you will get a little less than these numbers because you wont be at a perfect right angle.
A 1.75 inch cylinder with 1" rod gives ~3200 pounds of pull with 2000 psi
A 2 inch cylinder with a 1" rod gives ~4700 pounds of pull with 2000 psi
A 2 inch cylinder with a 1 1/8" rod gives ~ 4300 pounds of pull with 2000 psi
A 2.5 inch cylinder with a 1 1/8" rod gives ~ 7800 pounds of pull with 2000 psi
A 3 inch cylinder with a 1 1/4" rod gives ~ 11,700 pounds of pull with 2000 psi
Since your 3pt is rated around 2500 pounds, if it were my tractor, I would probably go with the 2 inch bore, 1 1/8 inch rod. I would get one that could handle a 5000 psi shock load which would equate to over 10,000 - 15,000 pounds depending on the direction of the shock load.
If I went bigger, I don't know if I could restrain myself
A 1 inch rod reduces surface area by 0.79 square inches. So a 1.5" cylinder with a 1" rod would exert 1.77 x system pressure on the push stroke but only 0.98 x system pressure on the pull stroke. So with 2000 psi you get about 2000 pounds of pull.
The list below gives an idea of how much weight you will be able to tilt up with different cylinders at a distance behind the links that equals the distance between the link attachment points. This doesn't take changing angles into acount and assumes a right angle between the cylinder and a line drawn through the link attachment points. In reality, you will get a little less than these numbers because you wont be at a perfect right angle.
A 1.75 inch cylinder with 1" rod gives ~3200 pounds of pull with 2000 psi
A 2 inch cylinder with a 1" rod gives ~4700 pounds of pull with 2000 psi
A 2 inch cylinder with a 1 1/8" rod gives ~ 4300 pounds of pull with 2000 psi
A 2.5 inch cylinder with a 1 1/8" rod gives ~ 7800 pounds of pull with 2000 psi
A 3 inch cylinder with a 1 1/4" rod gives ~ 11,700 pounds of pull with 2000 psi
Since your 3pt is rated around 2500 pounds, if it were my tractor, I would probably go with the 2 inch bore, 1 1/8 inch rod. I would get one that could handle a 5000 psi shock load which would equate to over 10,000 - 15,000 pounds depending on the direction of the shock load.
If I went bigger, I don't know if I could restrain myself
OP
CajunRider
Platinum Member
Thanks everyone for your input.
Yes I realize it's a bit much, but I got it for cheap 3x10 hydraulic toplink complete with double pilot check valve set up similar to what I see on Carter & Carter Machinery. I paid $110 bucks to a friend who bought it for his JD but decided he doesn't need it.
I checked and find out I can put a bushing in the eye and install it on my tractor. I guess if I want to use it I must be extra carefull with the control.
Yes I realize it's a bit much, but I got it for cheap 3x10 hydraulic toplink complete with double pilot check valve set up similar to what I see on Carter & Carter Machinery. I paid $110 bucks to a friend who bought it for his JD but decided he doesn't need it.
I checked and find out I can put a bushing in the eye and install it on my tractor. I guess if I want to use it I must be extra carefull with the control.
gladehound
Veteran Member
Well heck, if you alreay have the 3 inch cylinder put it on! You'll be fine as long as you don't get hydaulic power fever!
OP
CajunRider
Platinum Member
Got it installed. I had to buy a 3/4" - 1" bushings and actually had to grind off a little bit off the side of the eyelet to get it to fit. Now it works like a charm. As you said, I have to watch it a bit but I finally begin to get the box blade to behave the way I want.
coolslug
New member
I have a DK45se with a backhoe. I am curious about the hydraulic top link that you are discussing. What is a hydraulic top link? I have two hydraulic hoses in the back of my tractor that are hooked up to my backhoe. Are those hydraulics what you are talking about?
I am new to tractors so I have a good excuse for my dumb question.
I am new to tractors so I have a good excuse for my dumb question.