mini backhoe

On Wed, 18 Oct 2017 08:00:23 -0400, Ed Huntress


Appears to be a holdover from earlier farm tractor models. The bare tractor is only about 3200 lbs. With a loader and hoe it's nearly triple that. Did some searching yesterday and found several comments about the inadequacies of these brakes, and one mention of improving them by using oversize balls. Perhaps with disc friction material wear, the balls must move so far on the ramps that the drum rotates too much before the disc makes contact. I'll check it out next time the brake housings are off. Maybe the drum assembly can be shimmed a bit outboard.
I can see the attraction of using the vehicle's momentum to provide leverage, which works well on electric trailer brakes for example. But if the compound balls/ramp/disc thing was a good idea it should have been more popular.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

My first thought was that it's very compact, which may have been the main idea. My second thought was that it's something from an era when we expected to make adjustments and replacements to mechanical parts for all kinds of things -- including cars.
Still, I'd like to know what the engineers were thinking. Overrunning clutches in most applications are either on or off, like a Bendix drive; the balls are either fully released, or locked on. There doubtless are exceptions, but, as I said, the mechanism is known to give trouble when parts wear.
At least you can see what's going on. A digital version would be a real headache. d8-)
--
Ed Huntress

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 10/17/2017 2:45 PM, Ed Huntress wrote:

thru the hollow trans mainshaft .
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Tue, 17 Oct 2017 09:14:10 -0700, snipped-for-privacy@whidbey.com wrote:

Particularly when they are adjusted a bit loose, oe half worn out.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
A few tips from a fellow backhoe enthusiast here. Just what I can think of spontaneously:
- Try to design your backhoe to have smooth curves without sharp corners. T aper any reinforcement plates to make a diamond shape and use a tail-out on your welds. This helps to reduce stress concentrations and fatigue crackin g, which is a big problem on backhoes. Like this: http://www.millerwelds.com/resources/communities/mboard/filedata/fetch?id P7931
- You will not regret having power slew, even on a really small machine. Th ere is so much inertia in an extended backhoe that it takes a lot of torque to get the backhoe moving. I just checked the manual for my 7-ton backhoe loader and it gives the slew mechanism torque: 4860 ft/lb.
- Think about how comfortable the machine is going to be. Get a two-lever v alve block if you can (these are available second hand). Make sure the sitt ing position is comfortable. And make sure you can see down into the trench clearly, because that's a problem on a fair number of machines.
I've got a lot of backhoe information if you need it. Just let me know. And do show us the finished machine!
Chris
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Monday, October 16, 2017 at 5:14:47 PM UTC-4, Christopher Tidy wrote:

f spontaneously:

Taper any reinforcement plates to make a diamond shape and use a tail-out on your welds. This helps to reduce stress concentrations and fatigue crack ing, which is a big problem on backhoes.
That is one of the things I do not like about the plans I have. Some place s look like they would be big stress concentrators.

I am convinced. If you have a hydraulic pump, tank ,and filter, might as well have power everything.
Get a two-lever valve block if you can (these are available second hand.)
Not sure I understand what you are saying. There are four hydraulic cylind ers so one needs four valves. Are you saying use two two lever valve block s instead of a 4 valve block?
I was thinking about a 3 valve block for the three cylinders used in diggin g and a 1 valve block for the boom swivel. So the one valve block could be mounted so it is actuated left and right rather than forward and aft. Eve n better might be a swivel valve that is operated by one's feet. Have no t got my head around how to do that.
Dan

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Tue, 17 Oct 2017 17:25:46 -0700 (PDT), " snipped-for-privacy@krl.org"

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I was thinking about a 3 valve block for the three cylinders used in digging and a 1 valve block for the boom swivel. So the one valve block could be mounted so it is actuated left and right rather than forward and aft. Even better might be a swivel valve that is operated by one's feet. Have not got my head around how to do that.
Dan ===========================You might consider if you would ever want a manual or hydraulic thumb, perhaps to lift stumps or boulders out of the hole. Rocks can be difficult to grip with chains. http://www.acs-coupler.com/excavator/weld-on-stiff-arm-thumb-patriot
-jsw
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Am Mittwoch, 18. Oktober 2017 02:25:49 UTC+2 schrieb snipped-for-privacy@krl.org:

ces

You're welcome to post your sketches here. I'll take a look (send me an e-m ail if I don't) and others can give their opinions too. You won't get a det ailed analysis, but we can likely help you to avoid the worst stress concen trations.

)

nders so one needs four valves. Are you saying use two two lever valve blo cks instead of a 4 valve block?
No, I mean you could get one of these (valve block on the right): https://www.flickr.com/photos/13849392@N03/37723756736/in/dateposted-public /
The two big levers operate four spool valves (the small levers in the centr e are to raise and lower the stabiliser legs). You can see the tops of the valve spools in the pictures.
That's my own pile of backhoe spares and the block is going onto my machine soon (to replace a leaky block), so it's not for sale, but they are often available from places which stock used backhoe parts. Two levers are a lot more comfortable to use than four levers.
The idea of the bell crank and foot pedals definitely sounds possible. One backhoe manufacturer used to have some arrangement like that, but it wasn't a manufacturer I'm familiar with. Might have been Case.
One last thing: if you're going to use the machine a lot, think about pivot wear. Use large bearing surfaces, lock the pin so that wear only occurs at one interface, and maybe consider replaceable bushes.
Nice project. Enjoy it!
Chris
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Tue, 17 Oct 2017 17:25:46 -0700 (PDT), " snipped-for-privacy@krl.org"

Greetings Dan, My Case has what are called "Case Style" conrols. There are also "John Deere Style" controls. I have never used the Deere style controls but more than one person I have spoken to about backhoes has derided the Case style control. In fact, I was told that Case backhoes could be ordered new from the factory with Deere style controls. My case uses three levers and two foot pedals to control the how. As well as two levers for the outriggers. I think the Deere controls don't use the foot pedals. The foot pedals control the swing, the levers the the digging motions. I would advise against the foot pedal controls. This is because on my machine it is easy to step on the foot pedal when getting in and out of the seat. And this makes the boom swing fast. Which is dangerous. You should really take a close look at a backhoe control lever setup on a machine. Maybe your local heavy equipment rental place has one. Maybe talk to an operator or two. I rented a small excavator several years ago that used a joystick control. Much better. It took me almost no time to learn using the joystick. My Case controls were much harder to learn. They take more finesse. When you are digging the bottom of a ditch and it needs to be level the dipper has to be drawn backwards while at the same time it must be raised. It took me many hours to learn to do that operation even half way good. Finally, think about adding a thumb. My hoe doesn't have one but I got a cylinder recently to add one. I know, mission creep and all that. Cheers, Eric
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

I practice that whenever someone lets me try their machine, most recently a Kubota. Is there a control layout that makes it easier?
-jsw
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Am Mittwoch, 18. Oktober 2017 19:15:12 UTC+2 schrieb Jim Wilkins:

What layout does the Kubota use? I find the JCB cross-pattern levers pretty comfortable for this, but I'm not sure if they're better than other layouts.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

https://en.wikipedia.org/wiki/Excavator_controls
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Am Donnerstag, 19. Oktober 2017 12:49:30 UTC+2 schrieb Jim Wilkins:

Yes, the older JCB pattern is different. Lever motions at 45 degrees (into the corners).
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Thu, 19 Oct 2017 06:49:29 -0400, "Jim Wilkins"

IIRC Kubota uses Deere pattern (some were actually convertible "dual pattern" if memory searves correctly
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Wed, 18 Oct 2017 09:52:03 -0700, snipped-for-privacy@whidbey.com wrote:

On the one I used for about 150 hours a while back, all hand controls. Dipper control moves left and right for bucket tip. Boom control moves left and right for swing. That's if I remember right, because after a while it just becomes muscle memory. I'd used Case controls before and now after. No problem with either, although I'm occasionally still trying to move the Case levers sideways. :) Some will find either more instinctive than the other.

I find that the least dangerous thing on the 530. No handholds, no ROPS, vestigial fenders. Definitely made for an era when men were men, and sleepy heads lost limbs. :)
The Deere hoe I used was on a dozer. If you wanted to get out to be near the hoe, it was a long way around through the door. Much shorter to climb around the hoe controls, but one needs to take care to not snag a pant leg. Same with my skidsteer. No safeties at all. If you climb out with the bucket up you damned sure better not step on the lift pedal on your way out. They've engineered most of these risks out of modern machines. One friend's skidsteer has so many safeties it can be a pain sometimes. Another's needs its seat safety adjusted. He's heavier and has no issues. But when I'm in it and a bump lifts a bit of my weight off the seat, the brakes slam on. The halt bounces me back off the seat and then there's rounds two three and four before things settle down. Upside is that I can't remember the last time I felt the need to go on a carnival ride. :)
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Sunday, October 15, 2017 at 11:09:48 AM UTC-7, snipped-for-privacy@krl.org wrote:

. I may never make one, but I am proceeding on the grounds that I will.

do not need a real backhoe. I can really get by with just using a shovel. But a mini backhoe that would be say 3 times as fast as just using a shove l appeals to me.

nearly the same as a some what bigger machine. The hydraulic cylinders and hydraulic valves are the major expense and they would not be significantly less for a tiny backhoe.

ith them. Most of the drawings are three dimensional showing all the hidde n lines. And most dimensions are in the text. And the pages all have the same title block. But I did not pay a lot so can not expect a lot.

from the local scrap yard. I am intending to put the engine, hydraulic pum p, filter and tank as a unit with quick disconnects. So I can remove that part and connect it to a log splitter or what ever. And hope to find a bo at trailer at the scrap yard to supply the wheels. I have already bought some 3/16 rectangular 4 by 3 inch tubing for the booms and chassis. All in pieces only 4 feet long, but I have a welder. I also have some cut offs o f 1 inch rod and some 1" bronze bushings.

a mini backhoe. Good sources for hydraulic cylinders and valves would be nice. The Surplus Center is already bookmarked. Things to avoid would be nice.

f using a hydraulic cylinder. It seems like that might be okay to do. May be have a plan on how to add power to swivel the boom if using my feet is t oo much work. Or maybe figure out a way to use car clutch and brake parts to swivel the boom. I am sure there will be comments on that idea.

There are ones that places such as harbor freight sells, called a Towable b ackhoe. It has a small engine powering the hydraulic system. These cost aro und 2k or so and work great. If your handy, you could probably build a smal l one. Google them and see the design, it might be exactly what you need.
~
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

If this was a home economics NG, you would be right. But this is nominally a recreational metalworking NG, and making wrong economic
Making things when it makes no economic sense to do so, and keeping ridiculous old junk alive by fixing and making spare parts for it, is our equivalent of camping in a tent when you have a perfectly good house to sleep in.
--
Ed Huntress



Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:


Or spending a great deal of money to catch a few fish.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Sat, 21 Oct 2017 07:21:19 -0400, "Jim Wilkins"


That's why I use my SB lathe to build my own fishing rods.
A $1,000 investment and ten or twenty hours of work will save you $200. Such a deal!
--
Ed Huntress

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.