A hydraulic ram pulls as hard as it pushes

[Billhook]

Theory theory! At school at this point in my physics lessons my eyes would turn from the blackboard to the window to watch the girls in the school next door playing netball!
In practice on the farm, particularly with the Telehandler I find no difference between pushing and pulling with the Teleram, I assume this is because the machine has been set up to provide a maximum force on the return stroke and to prevent damage on the push stroke the relief valve is there to protect
So a lot depends on your pump and engine being powerful enough to maintain the 3000 psi requirement.

 

[Bill G]

Theory theory! At school at this point in my physics lessons my eyes would turn from the blackboard to the window to watch the girls in the school next door playing netball!
In practice on the farm, particularly with the Telehandler I find no difference between pushing and pulling with the Teleram, I assume this is because the machine has been set up to provide a maximum force on the return stroke and to prevent damage on the push stroke the relief valve is there to protect
So a lot depends on your pump and engine being powerful enough to maintain the 3000 psi requirement.

Well I agree I tended to look out the window at the gals but the best looking Physics teacher I ever knew I married. That is a different story though.

Now as for the subject at hand. I believe there is some huge misconceptions regarding the retraction stroke. There is a major difference between.
1. retraction (drop) with a load applied as a positive force
2. retraction with no load applied....neutral force
3. retraction with a load applied as a negative force

I will assure anyone a cylinder does not have the same force on retraction when the force is negative. (splitting on return stroke) It is pretty simple.

 

[muddstopper]

That depends on pump flow. If your pump flows 16GPM and your cylinder is a 4x24 it will not retract at the same speed as the same pump is contacted to a 3x24. It is simple physics (circ refs). No matter what a cylinder does not have the same force on retraction as it does on extension/lift.

You are trying to throw in a lot of different variables that has nothing to do with this conversation. Lots of ways to speed up a cylinder, but none of it has to do with a specific cyl with a specific pump flow, with a specific set pressure, with a specific bore and specific rod, extending and retracting at different speeds. As for the " No matter what a cylinder does not have the same force on retraction as it does on extension/lift" well I have already proved you wrong with the cyl I posted just above. Of course that cyl also wasnt a part of the original conversation either, it was just posted as possible solution for someone trying to build a splitter with the same retraction force as it has on extention. Also, using your example of a 3x24 and 4x24 cylinder not retracting at the same speed is not an absolute, a simple change in rod dia can make that 4 in bore cyl retract at the same speed or even faster than the 3in cyl. Of course when you start changing out rod sizes, its also going to effect the retraction force.

 

[muddstopper]

And there are various regeneration circuit designs.

Del, just so you will know, Regeneration does not work for retraction. Regeneration circuit work by returing the oil from the return side to the extend side of the piston. Basicily it uses the return flow from the rod end of cyl to fill the bore end of cyl with low pressure oil at the same time as the pump is supplying oil to the bore. All things considered, the pressure equalizes at both ends of the cyl and the surface area of the full piston being greater than the rod end piston area, the rod will always extend, never retract.

 

[Bill G]

You are trying to throw in a lot of different variables that has nothing to do with this conversation. Lots of ways to speed up a cylinder, but none of it has to do with a specific cyl with a specific pump flow, with a specific set pressure, with a specific bore and specific rod, extending and retracting at different speeds. As for the " No matter what a cylinder does not have the same force on retraction as it does on extension/lift" well I have already proved you wrong with the cyl I posted just above. Of course that cyl also wasnt a part of the original conversation either, it was just posted as possible solution for someone trying to build a splitter with the same retraction force as it has on extention. Also, using your example of a 3x24 and 4x24 cylinder not retracting at the same speed is not an absolute, a simple change in rod dia can make that 4 in bore cyl retract at the same speed or even faster than the 3in cyl. Of course when you start changing out rod sizes, its also going to effect the retraction force.

I guess you missed it when I said force. The is the essential issue with a wood splitter. The cylinder will not have the same force on retraction. If you think it does sobeit we will agree to disagree

 

[muddstopper]

I guess you missed it when I said force. The is the essential issue with a wood splitter. The cylinder will not have the same force on retraction. If you think it does sobeit we will agree to disagree

You think the word force is whats wrong with your statement? I think you missed what everyone else had already said and that is a cyl doesnt have as much pulling power, (force) on retraction as it does on extention. Quit being wishy washy and admit you tried to derail this thread by adding all kinds of senarioes that had nothing to do with the original topic. And I have already proven a cyl can have as much power/force pulling as it does pushing, so you are still trying to put lipstick on a pig.

 

[Bill G]

You think the word force is whats wrong with your statement? I think you missed what everyone else had already said and that is a cyl doesnt have as much pulling power, (force) on retraction as it does on extention. Quit being wishy washy and admit you tried to derail this thread by adding all kinds of senarioes that had nothing to do with the original topic. And I have already proven a cyl can have as much power/force pulling as it does pushing, so you are still trying to put lipstick on a pig.

The topic is if a cylinder on a wood splitter has the same force on retraction. You feel it does I feel it does not. There is no derailment there nor anything wishy-washy. I think it is quite clear so what is not clear to you?

 

[muddstopper]

The topic is if a cylinder on a wood splitter has the same force on retraction. You feel it does I feel it does not. There is no derailment there nor anything wishy-washy. I think it is quite clear so what is not clear to you?

Another bull crap reply from you. My very first post stated that a cyl doesnot have the same force on retraction as it does on extention.

The return stroke does not have the same force as the extend stroke. Although, you are correct that the return probably does have enough force to split most wood.

Del said the same thing first. Where the crap started was when you started the bull crap about a 3.5in cyl versus a 4in cyl. and using a 16gpm pump. Now, if you want to keep throwing all kinds of different senarios out there, I can discuss those too, but if you want to talk specifics, then try and stay on topic.
"The topic is if a cylinder on a wood splitter has the same force on retraction. You feel it does I feel it does not". Wrong again, you say its does not and I say it can, big difference. For a everyday box store splitter, you , as well as I, as well as several others, would be correct in saying a splitter does not have the same force on retraction as it does on extend. But if you are going to start adding variables to the mix, then those statements would only be correct part of the time and completely wrong other times.

 

[Bill G]

Another bull crap reply from you. My very first post stated that a cyl doesnot have the same force on retraction as it does on extention.

Del said the same thing first. Where the crap started was when you started the bull crap about a 3.5in cyl versus a 4in cyl. and using a 16gpm pump. Now, if you want to keep throwing all kinds of different senarios out there, I can discuss those too, but if you want to talk specifics, then try and stay on topic.

I am on topic. A cylinder no matter the size on a wood splitter will not have the same force on the return stroke. You can change all the variables you want it will not change the end result.

 

[muddstopper]

I am on topic. A cylinder no matter the size on a wood splitter will not have the same force on the return stroke. You can change all the variables you want it will not change the end result.

Your lumping all wood splitters into one group. Now just suppose I build a wood splitter using a center mounted piston in the middle of the bore with the rod extending out both ends of the cyl barrel. The cyl barrel would be attached to the wedge of the splitter and move with the wedge. Would that cyl have less force on one end than it does on the other end. I have already posted a pic of such a cyl so you know that cyl are made that way. If I hadnt retired from my old job, I could even show some pic of such a cyl in use.

 

[Bill G]

Your lumping all wood splitters into one group. Now just suppose I build a wood splitter using a center mounted piston in the middle of the bore with the rod extending out both ends of the cyl barrel. The cyl barrel would be attached to the wedge of the splitter and move with the wedge. Would that cyl have less force on one end than it does on the other end. I have already posted a pic of such a cyl so you know that cyl are made that way. If I hadnt retired from my old job, I could even show some pic of such a cyl in use.

You are looking for an argument and I will not entertain you.

 

[turnkey4099]

Well I agree I tended to look out the window at the gals but the best looking Physics teacher I ever knew I married. That is a different story though.

Now as for the subject at hand. I believe there is some huge misconceptions regarding the retraction stroke. There is a major difference between.
1. retraction (drop) with a load applied as a positive force
2. retraction with no load applied....neutral force
3. retraction with a load applied as a negative force

I will assure anyone a cylinder does not have the same force on retraction when the force is negative. (splitting on return stroke) It is pretty simple.

True but in most cases the difference isn't really enough to be very noticeable.

 

[turnkey4099]

You think the word force is whats wrong with your statement? I think you missed what everyone else had already said and that is a cyl doesnt have as much pulling power, (force) on retraction as it does on extention. Quit being wishy washy and admit you tried to derail this thread by adding all kinds of senarioes that had nothing to do with the original topic. And I have already proven a cyl can have as much power/force pulling as it does pushing, so you are still trying to put lipstick on a pig.

He's just up to his usual trolling habit.

 

[turnkey4099]

I am on topic. A cylinder no matter the size on a wood splitter will not have the same force on the return stroke. You can change all the variables you want it will not change the end result.

I'll make one try to break through that stupidity barrier of yours. Eveyone has said the SAME THING

 

[Bill G]

True but in most cases the difference isn't really enough to be very noticeable.

The difference is very noticeable but your experience may vary. I can give specific examples but they will not be regarding a splitter.

 

[muddstopper]

He's just up to his usual trolling habit.

Nah, he just trys to talk in absolutes and sound smart. His ignorance preceeds him and he just cant see it.