Automatic reciprocating hydraulic circuit?

[treaney]

Hi Folks,

I need an automatic reciprocating hydraulic circuit to operate off my Zetor Crystal's hydraulics. The desired function is to automate the function you would get with a two way spool valve that causes a cylinder to extend and retract. Normally this is done by manually moving the spool valve control lever. I would also like the cycle time and the dwell time i.e. the amount of time the cylinder spends fully extended to be programmable and to have a fast return function.

I will send a six pack of Guinesss to the first person to post an implementable hydraulic circuit diagram to achieve this. Get thinking folks...

Could a newer tractor (Zetor or other) with programmable electro-hydraulics be setup to perform this function?

TomZ
[glow=green,3]Tom in Ireland[/]

 

[treaney]

Hi Folks,

I need an automatic reciprocating hydraulic circuit to operate off my Zetor Crystal's hydraulics. The desired function is to automate the function you would get with a two way spool valve that causes a cylinder to extend and retract. Normally this is done by manually moving the spool valve control lever. I would also like the cycle time and the dwell time i.e. the amount of time the cylinder spends fully extended to be programmable and to have a fast return function.

I will send a six pack of Guinesss to the first person to post an implementable hydraulic circuit diagram to achieve this. Get thinking folks...

Could a newer tractor (Zetor or other) with programmable electro-hydraulics be setup to perform this function?

TomZ
[glow=green,3]Tom in Ireland[/]

 

[lspringeradelphianet]

Tom - trying to split wood faster, are you? I just use a spool valve that has detents for both directions - it's the easier way to get faster.

But the absolute fastest way to split wood that I have seen is to use the mechcanical kind that has a flywheel and a rack and pinion drive.

 

[lspringeradelphianet]

Tom - trying to split wood faster, are you? I just use a spool valve that has detents for both directions - it's the easier way to get faster.

But the absolute fastest way to split wood that I have seen is to use the mechcanical kind that has a flywheel and a rack and pinion drive.

 

[arctic003]

Hi Tom

Have you thought about using something electro-mechanical to physically move the spool valve lever?

Maybe at its simplest, something like a car wiper motor turning a threaded rod, through a nut attached to the spool valve lever? Then you'd just need a couple of microswitches to signal the movement limit and a 555 timer circuit to set the amount of delay needed at each end... just a suggestion.

003

PS. Plus of course a huge emergency stop button...

 

[arctic003]

Hi Tom

Have you thought about using something electro-mechanical to physically move the spool valve lever?

Maybe at its simplest, something like a car wiper motor turning a threaded rod, through a nut attached to the spool valve lever? Then you'd just need a couple of microswitches to signal the movement limit and a 555 timer circuit to set the amount of delay needed at each end... just a suggestion.

003

PS. Plus of course a huge emergency stop button...

 

[treaney]

Hi Popeye and Arctic,

Thanks for your suggestions!

As my design must be absolutely bulletproof, I'm steering towards using a Micro PLC - probably a Siemens Logo! as the controller which is available for around 100. I will have to use electro-hydraulics which will be expensive however.

The function I want is illustrated by circuit 6[/] on:
http://www.ul.ie/~gordons/martinleary/circuits.htm
Pneumatics is easy - you can exhaust the return to atmosphere - not feasible with hydraulics but this illustrates the functionality I require.

The Micro PLC will allow me to control the dwell time i.e. the amount of time the ram is extended. Big pipes (and possibly a special valve) will permit a fast return.

TomZ
[glow=green,3]Tom in Ireland[/]

 

[treaney]

Hi Popeye and Arctic,

Thanks for your suggestions!

As my design must be absolutely bulletproof, I'm steering towards using a Micro PLC - probably a Siemens Logo! as the controller which is available for around 100. I will have to use electro-hydraulics which will be expensive however.

The function I want is illustrated by circuit 6[/] on:
http://www.ul.ie/~gordons/martinleary/circuits.htm
Pneumatics is easy - you can exhaust the return to atmosphere - not feasible with hydraulics but this illustrates the functionality I require.

The Micro PLC will allow me to control the dwell time i.e. the amount of time the ram is extended. Big pipes (and possibly a special valve) will permit a fast return.

TomZ
[glow=green,3]Tom in Ireland[/]

 

[arctic003]

Hi Tom

As the system is fairly simple, maybe you don't need a microcontroller to control your dwell time? Wouldn't dedicated timer circuitry (ie the 555 suggestion) be a lot simpler and a thousand times cheaper?

I have used 555s in fairly noisy environments - for example electric fence chargers - with good results.

If you do use a microcontroller there is lots of stuff on the net. I made a PIC programmer a couple of years back and had fun making it do useful things - ok, well, flashing lights and sending "HELLO WORLD" to the serial port of my portable

 

[arctic003]

Hi Tom

As the system is fairly simple, maybe you don't need a microcontroller to control your dwell time? Wouldn't dedicated timer circuitry (ie the 555 suggestion) be a lot simpler and a thousand times cheaper?

I have used 555s in fairly noisy environments - for example electric fence chargers - with good results.

If you do use a microcontroller there is lots of stuff on the net. I made a PIC programmer a couple of years back and had fun making it do useful things - ok, well, flashing lights and sending "HELLO WORLD" to the serial port of my portable

 

[treaney]

Jean-Paul,

I will need a Micro PLC with about 10 digital IO. There are a couple of other cylinders in the machine I am designing.

Re cost - The Simen Logo! starts at 100. You can't get much cheaper than that.

I used the ubiquitous 555 timer a lot about 25 years ago.

When you say PIC - do you mean Programmable Interrupt Controller as in the Intel 8259 PIC with NMI etc.

TomZ
[glow=green,3]Tom in Ireland [/]

 

[treaney]

Jean-Paul,

I will need a Micro PLC with about 10 digital IO. There are a couple of other cylinders in the machine I am designing.

Re cost - The Simen Logo! starts at 100. You can't get much cheaper than that.

I used the ubiquitous 555 timer a lot about 25 years ago.

When you say PIC - do you mean Programmable Interrupt Controller as in the Intel 8259 PIC with NMI etc.

TomZ
[glow=green,3]Tom in Ireland [/]

 

[arctic003]

<When you say PIC - do you mean Programmable Interrupt
<Controller as in the Intel 8259 PIC with NMI etc.

No, the PIC16C84 Microcontroller IC made by Microchip Inc.

 

[arctic003]

<When you say PIC - do you mean Programmable Interrupt
<Controller as in the Intel 8259 PIC with NMI etc.

No, the PIC16C84 Microcontroller IC made by Microchip Inc.

 

[treaney]

I did a lot of work in the early 1980's with Intel 8 bit micro-controllers - the 8051 family.

The PIC is a more modern version.

TomZ
[glow=green,3]Tom in Ireland[/]

 

[treaney]

I did a lot of work in the early 1980's with Intel 8 bit micro-controllers - the 8051 family.

The PIC is a more modern version.

TomZ
[glow=green,3]Tom in Ireland[/]

 

[Renze]

Hey hey, you bitfreaks, the 8051 processor was before my time !!
please additional information ??

The oldest i've gamed and wrote essays with, was a 8088 i believe..? In those days Motorola was the biggest concurrent of Intel, and AMD was never heard off...

About your system, you could use a push rod attached to your cylinder. When it is fully extended, it pushes the pushrod and the hydro lever kicks back.

With a different plumbing, and a spring to your cylinder, you can use a spool block with automatic kick-out, like most newer tractors have. When there is max. pressure and no flow (when cylinder is fully extended) it will kick out, and the spring will pull your cylinder back in. So all you do is operate the outgoing stroke, (with a 2/3 valve ??) and it will kick out when the stroke is complete, and the spring will pull it back.

But... If you want to operate more cylinders in the same cycle, a PLC would indeed be better...

By the way, what are you designing ?? an automatic wood chop-to length/splitter combo ?? they already exist, some Finnish companies sell them.

 

[Renze]

Hey hey, you bitfreaks, the 8051 processor was before my time !!
please additional information ??

The oldest i've gamed and wrote essays with, was a 8088 i believe..? In those days Motorola was the biggest concurrent of Intel, and AMD was never heard off...

About your system, you could use a push rod attached to your cylinder. When it is fully extended, it pushes the pushrod and the hydro lever kicks back.

With a different plumbing, and a spring to your cylinder, you can use a spool block with automatic kick-out, like most newer tractors have. When there is max. pressure and no flow (when cylinder is fully extended) it will kick out, and the spring will pull your cylinder back in. So all you do is operate the outgoing stroke, (with a 2/3 valve ??) and it will kick out when the stroke is complete, and the spring will pull it back.

But... If you want to operate more cylinders in the same cycle, a PLC would indeed be better...

By the way, what are you designing ?? an automatic wood chop-to length/splitter combo ?? they already exist, some Finnish companies sell them.

 

[arctic003]

< By the way, what are you designing ?? an automatic wood chop-to
< length/splitter combo ?? they already exist, some Finnish
< companies sell them.

They are really popular at least in this part of Finland, and I guess all over the country.

You feed tree-trunks in at one end, and chopped to length split firewood comes out of the other end on a conveyor belt, straight into your waiting trailer...

http://www.agrimarket.fi/main.cfm?iA=2356

 

[arctic003]

< By the way, what are you designing ?? an automatic wood chop-to
< length/splitter combo ?? they already exist, some Finnish
< companies sell them.

They are really popular at least in this part of Finland, and I guess all over the country.

You feed tree-trunks in at one end, and chopped to length split firewood comes out of the other end on a conveyor belt, straight into your waiting trailer...

http://www.agrimarket.fi/main.cfm?iA=2356