Backhoe Design Ideas

[dfkrug]

Why do you say the slight restriction is desirable? Is it just a speed issue?

It dampens the jerkiness you will get as a valve is quickly opened and
closed. Another way to achieve this dampening effect is to install
restriction orifices somewhere between the valve work port and the
cyl. I remember that my JD leader had them from the factory. You
only want damping in the work circuits.

 

[dfkrug]

Thanks for raining on my parade. But, seriously, that's the kind of advice I want to hear now vs. after I'm half way through the build.

So, let me ask you this... Did you ream before and after, or just after? I guess what I really want to know is if having the machine shop do the reaming will make the hand reaming I have to do after welding easier.

I have experimented with tightly fitting male-female self-aligning frame
elements and it is very tough to wiggle around a 1000+ lb hoe to get
them together (or apart).

As for reaming, first choose your pin/bushing strategy. 1.000" DOM bushings
will be too small for 1.00" pins. You will have to oversize your bushings or
use undersize pins (25mm or 63/64"). If you go with the latter, any reaming
is only after you weld. I sold my reamer from that project and since then
I have done dozens of bushings. I am much better at heat managment now,
so I have not had to ream at all. I talk about that in my 4-in-1 bkt project.
I just cut out and welded in new bushings yesterday on my pallet fork
frame, and they did not distort at all.

 

[dfkrug]

There is a reason you do not see tight-fitting self-aligning mounts like what
you describe. You are asking too much of your mount when it is constraining
in all dimensions. Alignment will have to be perfect before the mating parts
will slide together. With a 4-pt mount, the lower pin/saddle alignment
provides alignment in only 2 dimensions (up/down & left-right), leaving the
rotation angle to be constrained by the top 2 pins. My suggestion is to
go to a tractor dealer and study a commercial TLB, or at least one of the
very modern 4-pt setups.

This whole concept of self-alignment deserves more attention, IMO. In
my previous post, I meant to say the lower part of the 4-pt frame
constrains the hoe from left to right as it gets mounted. but the up/down
movement is constrained downward only. If you fabricate a couple of "ears"
on the lower subframe mount, the action of moving the hoe closer and closer
will be self-aligning as the hoe hits the "ears" and constrains left-right
movement. Hard to describe, but it makes sense when you see it. ANYTHING
you can do to allow the hoe to self-align while mounting will be a Good
Thing. You will appreciate that if you ever have to spend the hours JOEL
is talking about trying to get a difficult-to-mount hoe on the tractor. BTDT

 

[charlz]

This whole concept of self-alignment deserves more attention, IMO. In
my previous post, I meant to say the lower part of the 4-pt frame
constrains the hoe from left to right as it gets mounted. but the up/down
movement is constrained downward only. If you fabricate a couple of "ears"
on the lower subframe mount, the action of moving the hoe closer and closer
will be self-aligning as the hoe hits the "ears" and constrains left-right
movement. Hard to describe, but it makes sense when you see it.

I believe you can see this in my pic here of the rear hoe brackets. The slots are for a cross-bar on the hoe, aligns it up/down and front/rear. The 'ear' sticking out of the side just fits between the rails that run forward to the loader cross member. This aligns left to right. Once I have the pump attached and the cross bar sitting in those notches it is a matter of using the swing and crowd on the hoe to get the front bolts (on the arms that run forward to the loader cross member) to align. Some days it works like cake and other days it can be a pain. The initial alignment of the tractor when backing up to the hoe is the tricky part.

On the Kubotabooks.com site there are several Kubota backhoe parts manuals that might give you some design ideas.

 

[Renze]

It dampens the jerkiness you will get as a valve is quickly opened and closed.

i've never heard of restrictions in work lines to get smooth controls.. The official solution is to change the valves for ones with slots in the edges, so they cheat some oil before they fully open... You can also grind them yourself, we've done that on payloaders that needed more precise tilt control when used with a 20 meter hoist boom on the quicktach.

A more efficient way to decrease jekiness is to reduce the speed by decreasing engine rpm, instead of wasting power by restrictions.

 

[philbuilt]

Iplay,
I thought I would post the link to my subframe fab. I had allot of the same concerns and mybe it would give you som ideas. This link started as a repair of my woods loader frame. I hope it helps.
http://www.tractorbynet.com/forums/customization/95563-woods-1012-fel-mount-problem.html

Phil

 

[Iplayfarmer]

Iplay,
I thought I would post the link to my subframe fab. I had allot of the same concerns and mybe it would give you som ideas. This link started as a repair of my woods loader frame. I hope it helps.
http://www.tractorbynet.com/forums/customization/95563-woods-1012-fel-mount-problem.html

Phil

Wow!! Excellent fabrication skills. Thanks for that post. I've got your subframe all figured out, but I'm not sure how your backhoe attaches to your subframe. It almost looks like you have a second subframe that interconnects with the subframe that stays on the tractor.

I'd love to see a picture of the tractor and then a picture of the backhoe when they are not attached to each other. That may help me figure it out a little better.

With so many testimonials and convincing arguments against my first draft attempt at a quick connect, I've changed my mind. I need to get into the details of it more, but I'm going to re-visit the connection mechanism to get something more workable.

Thank you to all for the input. This is a HUGE help.

 

[philbuilt]

Iplay,
I did make a separate frame that goes under the tractor and slips onto the pins that you see at the mid point. Then I put the riggers down and pin the back. Also note the hitch bar goes though as well.
I went looking to see if I had some more pictures and I have found a few. They were posted before but I can't remember where.
,,

,,.
I added the last few to show some of the uses.
The rock was heavy and it pulled it out without trouble. I thought that you would like to see the trailor attached. This has worked very nice. I did lower the hitch some for easer loading. With the offset I can dig and load without unhooking.
Phil

 

[Iplayfarmer]

Iplay,
I did make a separate frame that goes under the tractor and slips onto the pins that you see at the mid point. Then I put the riggers down and pin the back. Also note the hitch bar goes though as well.
I went looking to see if I had some more pictures and I have found a few. They were posted before but I can't remember where.
View attachment 123625,View attachment 123626,View attachment 123627

View attachment 123628,View attachment 123629,View attachment 123630.
I added the last few to show some of the uses.
The rock was heavy and it pulled it out without trouble. I thought that you would like to see the trailor attached. This has worked very nice. I did lower the hitch some for easer loading. With the offset I can dig and load without unhooking.
Phil

Holy Cow, Phil!! That's a big rock!

Thank you very much for those pics. That's a big help.

 

[Iplayfarmer]

For about a 100 I bought a pump from surplus, used a coupler to couple to my PTO shaft and then welded up a bracket for it to line up with the PTO shaft and keep the pump from spinning. Never a problem in approximately 3 years of use. No need for a dedicated PTO pump, those things are big money.

Joel

Can you give me more details on what you did? Did you hook up to the rear or the mid PTO? I've been looking on Surplus Center's website. I can see pumps that I think would work, but I haven't found anything to adapt from the PTO to the pump. My mid PTO is a 1 inch 15 spline. My rear PTO is a standard 540 PTO.

There's this that matches the PTO output shaft, but the other end doesn't match any of the pumps that I've found in the price range on thier website.

 

[JoelD]

Can you give me more details on what you did? Did you hook up to the rear or the mid PTO? I've been looking on Surplus Center's website. I can see pumps that I think would work, but I haven't found anything to adapt from the PTO to the pump. My mid PTO is a 1 inch 15 spline. My rear PTO is a standard 540 PTO.

There's this that matches the PTO output shaft, but the other end doesn't match any of the pumps that I've found in the price range on thier website.

I found an adapter from standard 6 spline to 1/2 keyed. My tractor had a 31/32 10 spline rear PTO shaft (LONG story) I found an adapter to standard 6 spline, then slipped the six spline adapter over that and put the 1/2 inch keyed pump into the other end of the adapter.

Here's some examples.

http://www.hubcityinc.com/media/q.pdf

Just slip the adapter over your six spline rear PTO then slip the pump into the other end and use a key and a couple of set screws and you are good to go.

Sorry my pictures don't make it all that clear, I've sold the machine otherwise I'd send you more pictures, but it's fairly straight forward.

Nice being able to use any pump, rather than PTO pump.

Joel

 

[dfkrug]

i've never heard of restrictions in work lines to get smooth controls.. The official solution is to change the valves for ones with slots in the edges, so they cheat some oil before they fully open... You can also grind them yourself, we've done that on payloaders that needed more precise tilt control when used with a 20 meter hoist boom on the quicktach.

A more efficient way to decrease jekiness is to reduce the speed by decreasing engine rpm, instead of wasting power by restrictions.

Well the speed of the cyl movement is an issue mostly for the swing cyl(s)
on these small hoe attachments. Much less for the boom, and not all all
for the curl cyl. Lots on TBN about damping the swing circuit. The
restrictions on my JD FEL were for the curl only.

As for cheating some oil around the lands in the spools, that makes sense.
I wonder if any of these hoe attachments have that. My current hoe's
valves have a very noticable position mid-stroke of each lever which cuts
off flow to/from each work port, as well as blocks the valve center. It
is less apparent on other stack valves I have used. Maybe I could use
some valve customization....

 

[Renze]

Well the speed of the cyl movement is an issue mostly for the swing cyl(s) on these small hoe attachments. Much less for the boom, and not all all
for the curl cyl. Lots on TBN about damping the swing circuit.

That makes sense..

 

[Iplayfarmer]

Well the speed of the cyl movement is an issue mostly for the swing cyl(s) on these small hoe attachments.

I guess that answers my next question. I have two 3" cylinders for the swing. I was wondering whether to plumb them as single acting or double acting. Double acting has a lot more force and may be smoother, but single acting requires less flow (i.e. Faster). If swing speed is frequently an issue with these smaller hoes, then I will plumb them as dual acting cylinders. I suppose that worst case I can always go back in and plumb them single acting later if I want more swing speed.

 

[charlz]

Mine has a 'cushion valve 1000psi' on the SA swing cylinders... is this to 'slow start' the swing and take some of the jerk out of it?


As for a PTO to pump adapter the p/n for mine is 70020-00786 but TractorSmart shows the price as $92.56 It is just at PTO coupler welded onto a keyed piece with a couple set screws that slides over the pump shaft. Seems easy enough but maybe not so easy to make yourself?

 

[Iplayfarmer]

Mine has a 'cushion valve 1000psi' on the SA swing cylinders... is this to 'slow start' the swing and take some of the jerk out of it?


As for a PTO to pump adapter the p/n for mine is 70020-00786 but TractorSmart shows the price as $92.56 It is just at PTO coupler welded onto a keyed piece with a couple set screws that slides over the pump shaft. Seems easy enough but maybe not so easy to make yourself?

I went back and looked at hydraulic pumps at Surplus Center. To get a pump that would put out enough volume at 540 RPM would cost over twice as much as a pump that I'd run at 2000 RPM (i.e. belly mount).

I'm really spending too much time on the hydraulics. I'm going to connect to the tractor hydraulics at least initially to see how it works. I need to get my 4 point mounting mechanism figured out for now.

 

[JoelD]

I don't know what tractor you are hooking up to (GPM of tractor). I've got my surplus center catalog #282

My tractor had three PTO settings (older Kubota), 540, 700+ and then 1250 I think it was.

My current tractor, Kioti LK has two settings 540 and 1000.

If you've got a faster setting than 540 that would permit a smaller pump.

Pump 9-7154 is rated at 12.24 GPM at 2000 rpm, that would give you 6 PGM at 1000, which should work fine depending on the size of the backhoe you are building. I ran this pump at 540 and it worked find on my 5 foot hoe on my little Kubota B6000 (the tractor's pump was somewhere aroung 2 gpm, little tractor). The pump costs $99.

The adapter I spoke about is on page 110, with the quick connect to the tractor and the female end ready for the pump shaft with key way.

There's a number of ways to come up with a combination that would work.

Page 32 has spline shafted pumps with higher outputs, which max out in price at $199.

Good luck,

Great fun when it all comes together.

Sincerely,
Joel

 

[Iplayfarmer]

I don't know what tractor you are hooking up to (GPM of tractor). I've got my surplus center catalog #282

My tractor had three PTO settings (older Kubota), 540, 700+ and then 1250 I think it was.

My current tractor, Kioti LK has two settings 540 and 1000.

If you've got a faster setting than 540 that would permit a smaller pump.

Pump 9-7154 is rated at 12.24 GPM at 2000 rpm, that would give you 6 PGM at 1000, which should work fine depending on the size of the backhoe you are building. I ran this pump at 540 and it worked find on my 5 foot hoe on my little Kubota B6000 (the tractor's pump was somewhere aroung 2 gpm, little tractor). The pump costs $99.

The adapter I spoke about is on page 110, with the quick connect to the tractor and the female end ready for the pump shaft with key way.

There's a number of ways to come up with a combination that would work.

Page 32 has spline shafted pumps with higher outputs, which max out in price at $199.

Good luck,

Great fun when it all comes together.

Sincerely,
Joel

I just got the newest SC catalog out of the mailbox about an hour ago. I think I see the adapters you are talking about. I only have 540 RPM on the rear, so I'd need a pretty big pump to get better flow. I keep thinking there has to be a way to use the 2000 RPM Belly PTO. The pump I'd need for 2000 RPM is under $100; but I'd have to adapt from my 1" 15 spline shaft and move it forward and to the side a bit so I can tuck it up above the subframe. The parts to move it add up pretty quick.

For now I'm keeping my eyes on E-bay for a pre-fab PTO pump.

 

[Iplayfarmer]

I just bought a PTO "Hydrolic" pump off e-bay.

Here's the item... Charlynn PTO Drive Hydrolic Pump - eBay (item 170314394646 end time Mar-30-09 18:41:14 PDT)

If you are the seller, thanks. If I was bidding against you, neener neener...uh... I mean sorry you didn't win.

I really don't know any of the specs on this pump. Feel free to chime in now and tell me if it's not going to work. The sooner I know, the easier it will be to take.

 

[JoelD]

How big is the return hose fitting? Not sure that's gonna flow enough oil? Nothing to loose for that price. Only one way to find out, if it doesn't work swap out for another. No big deal in the end.

Certain there is someone on this forum who would know something about that pump.

Good luck,
Joel