Push or pull

[AKKAMAAN]

Trying to follow the excavator part of the thread .....the so called dipper arm is the one that hold the bucket...right!?....and the dipper arm is jointed to the boom....
I just cant find the difference between backhoe and excavator, in how dipper cylinder is attached.....:confused2:

There is a difference on the boom cylinder placement...

Who wants a backhoe with the dipper cylinder under the boom???

I'm just not following this part....Please explain....

 

[Iplayfarmer]

Trying to follow the excavator part of the thread .....the so called dipper arm is the one that hold the bucket...right!?....and the dipper arm is jointed to the boom....
I just cant find the difference between backhoe and excavator, in how dipper cylinder is attached.....:confused2:

There is a difference on the boom cylinder placement...

Who wants a backhoe with the dipper cylinder under the boom???

I'm just not following this part....Please explain....

In the two pics you posted, the dipper is run the same... cylinder pulls to extend backhoe. I haven't seen many with the dipper cylinder on the underside of the boom, but I assume that's what the OP was referring to. In the case of the pics you posted, the booms are what are different. The excavator boom is raised by the extension stroke of the cylinders. The backhoe boom is raised by the retraction stroke.

 

[picker77]

Push creates more FORCE than pull. Pull creates more SPEED than push..

example
a 4" bore diameter cylinder with a 2" diameter rod will have 12.57 inch^2 area on capped side, and 12.57 - 3.14 = 9.43 inch^2 area on the rod side
cylinder will push 12570 lbs and pull 9430lbs, for each 1000psi pressure

speeds will be about 3"/sec pushing, and 4"/sec pulling, for each 10 GPM pump flow.....

In accordance with this concept, a hydraulic top link should logically be installed with the rod end toward the tractor, so the end with the most piston area (the non-rod end) is the end that will resist that heavy load--right?

I ask because I'm getting ready to install HTL on my tractor later this week. I can hang the cylinder in either direction, but having the rod end toward the implement would probably be easiest for hose connections and routing, and generate the least amount of hose movement during use. However, I've seen HTL installations done both ways. So is there really a right and wrong way, or is the difference so small it's best to just do it so it's most convenient?

 

[radman1]

In accordance with this concept, a hydraulic top link should logically be installed with the rod end toward the tractor, so the end with the most piston area (the non-rod end) is the end that will resist that heavy load--right?

I ask because I'm getting ready to install HTL on my tractor later this week. I can hang the cylinder in either direction, but having the rod end toward the implement would probably be easiest for hose connections and routing, and generate the least amount of hose movement during use. However, I've seen HTL installations done both ways. So is there really a right and wrong way, or is the difference so small it's best to just do it so it's most convenient?

As far as the cylinder is concerned, it does not matter which end is front or back. The forces are the same on the cylinder. However, I recommend you install with the rod/stroke facing toward the back and away from the tractor. Why? If the rod faces away from the tractor (toward the implement) the hoses will not be changing length as you retract and extend the cylinder. Otherwise with an 8" stroke on the top link, the hoses will also have to extend and retract as the rest of the cylinder moves. It is hard enough to get the postion of the hoses correct when raising and lowering an implement and not have to deal also with the change in the hydraulic extension/retraction.
I live in farm country and lots of HTLs on ag tractors. To be honest, I have never seen a HTL attached with the rod/stroke end attached to the tractor. It is not the best method.

 

[Iplayfarmer]

I have seen pictures of backhoe attachments that have the rod end toward the tractor. On these, the hoses are routed to the middle of the boom and double back to attach to the cylinder.

As far as force is concerned it's not going to matter. If your design lends itself better to routing hoses for a rod end near the tractor, do it that way.