So I'm picking up a thumb for my backhoe, I don't need one that'll lift the world just to grab brush and trash and move small rocks. Its an early model 580CK, gas engine, maybe a model 33 hoe? Anyway, I'm pondering what's involved with adding a thumb, I did add a manual valve for a power angle plow where the RTD assembly was supposed to go but I'm wondering about adding one for a thumb. I have the three stick with foot swing so all mechanical valves, I was wondering if there is an electric valve out there that'd have its relief plumbed back into the outbound hydraulic line so the thumb would run on a simple switch. I'll be happy with the manual thumb for quite a while I suspect. Thanks in advance!!
Well, if the original valve you're pulling oil from for pressure is power beyond with a separate tank return line, the upstream relief valve should cover you on the inlet side of your new thumb valve. You should have at least one circuit relief teed into the line from the valve to the butt end of the thumb cylinder, so when you clamp against the thumb with the bucket it returns oil to tank and you don't blow something up. Believe me it happens. Ideally you use a block with two reliefs, one for each end of the cylinder and has a tank return line. Do NOT use a crossover relief with no tank return, again, you will blow something up, just so you know. At that point probably any open center 4 way manual or solenoid valve will do the job if it's rated for the pump flow and pressure. Something like this with a matching subplate might work: http://www.baileyhydraulics.com/product/9267 This type of valve has to be the last in the chain with an unrestricted return to tank.
fast............ dad2six added a thumb to his you might pm him but i think his is manual here is a thread that has his in some of the pics..... HeavyEquipmentForums jump to page 3 and you can see some pics and towards the end of thread he has it mounted.........
xpackdeals: Yep, that looks like the same thumb that I ordered, just steel and fairly light duty, I think it'll fit my needs lantraxco: Yeah, this isn't anything snazzy like power beyond, its a single circuit from pump to tank with open center valves. That looks similar to the valves in Northern Tool or Surplus center, I was thinking I really only need a relief on the one line that's under squeeze from the bucket though it'd create a vacuum in the other side but then you'd have a void in the space. If I recall, the return runs through a filter then back to the tank so mostly un restricted.
I put a thumb on a 580K. My tractor had a third section in the loader, probably had a 4 in 1 loader bucket once. I repurposed it. I have to reach back with my left hand to control the thumb. I ruined the hydraulic cylinder right off the bat. It was explained to me the relief circuit is designed to divert incoming pressure not relieve high pressure already there. The expert added a valve I believe is homemade. It has four ports, mounts on the thumb, and when I squeeze too hard, it moves oil from one side of the cylinder to the other. As for control, there are selector valves, or you can use the valve you already have for angling the plow with quick couples. ANBO offers an electric diverter valve to select one function or the other. Willie
Looks like the loader valve is power beyond, the stabilizer valve is power beyond, that's how they pass pressure downstream. The backhoe valve is not I don't think, it just dumps back to tank through the filter. How did you plumb in your extra valve? Most valves won't take much pressure on the tank port, it will blow the spook seals out at the least. Some solenoid valves will take back pressure but they will have an extra tank port to drain off internal leakage. Yeah, you only really need the relief on one line for the back end of the thumb cylinder, you could put a tee in the other line, with a 5 psi check on the branch connected to a tank line, so it could suck oil rather than sucking dirt in around the rod seals if you wanted to.
OP, the manual thumb is all you need, from your description of potential use. Take a look at the manual Hoe Clamp from Amulet, no hydraulics. The way my Dig-more boom is, I couldn't use a hydraulic thumb, but the Hoeclamp can lift 4K# with my 700 size hoe. Lots more complications going with oil.... http://www.amulet.com/products/hoeclamp/
So on this case, the outlet comes from the pump, into the loader valve and then out into a second option control valve, generic cross single spool valve, open center, onto a short hose with a QD that continues on to the backhoe valve, comes out with another long hose with a QD that runs up to the filter and return. You disconnect the pair of QD's to bypass the backhoe for removal else the hydraulic system is dead headed. Good idea on the reverse suction line. can just make one with a fitting, spring and check ball
El Hombre: I think that's true but then there is the coolness factor of having more snazzy stuff
Went with the one from Titan products, it was cheaper than I could build it for myself, it doesn't say where its made but the quality of the cardboard box seems to indicate somewhere north of Burma. The steel for the teeth looks to be regular hot rolled steel but its strong enough not to flex under a full grab, it was $210 and weighed 175 pounds, overall, I think it'll do everything I need it to do. Wasn't any instructions but that's easy enough to figure, a bit of grinding and welding and its ready to go. Mostly all 1/2 inch and 5/8 plate through and through.
El Hombre, Those hoe clamps from Amulet are pretty slick but I don't think they make one for a CK or a K. I know it will work on a C but I'm not sure which others it will work on. I remember asking them about one for a CK, C, or a K and they said no way on the CK and K - only the C. I'd think you could adapt their design if you were making one yourself.
I looked at the Amulet for my CK and would have had to get a coupler made to adapt an existing design. I spoke with Mark at Amulet and he suggested a few other options. In the end, I purchased the jaws and a link from them for a hydraulic thumb, which is still on sitting on the shop floor until I get my rebuild done. The plan is to make plywood copies and work out the geometry before putting any holes in the steel. One of these days....
That's exactly how I made mine; plywood models. That was 17 years ago, I go out an look at it and still wonder how I was able to make that work the first time....I had a lot more mental ability back then, just day to day junk is taxing now....
Ha, Ha, I know what you mean about taxing. Having a new project gives me a chance to dust off the cobwebs and get back to stuff I used to know or was taught by my father many years ago. No fancy programs, calculators or gadgets. Just some common sense, a rule and caliper and the handbook with the tables. He could repair or build anything with nothing. They don't make them like that anymore. With my tractor rebuild, I'm doing stuff again that I haven't in the last 30 years. Its fun but sometimes an afternoon snooze is in order to give the mind a rest.
one of my co workers picked up a 580E with the case tagged cummins and extendahoe, the hoe clamp looks like his only option. I suggested a hydraulic thumb mounted only to the fixed dipper section.
Just posted this in another thread somehow by accident....sorry. Anyway, I just acquired a 1972 case 580B and it came with a thumb to my surprise, pretty heavy duty and seems to be plumbed into a manual switch on the boom that taps in to the bucket curl circuit. It seems you are meant to reach out and throw the lever when you want to activate the thumb... I had assumed it came stock as it appeared to me to be so, but now that I have educated myself a bit more in how these machines came, I know better. If anyone needs pics let me know and I'd be happy to oblige, however it seems I need that functionality activated in my forum privileges... please?
Yeah post a few pictures of your set up please.
I've seen valves with a 'diverter' function listed on surplus center so steal a function to run something else
here are some pics of my setup... Its new to me and still pretty rough, but it appears to divert most of the flow, such that if you are trying to pick up a rock for example, the bucket would curl until it encounters a load then the thumb would engage to grab it... Like I said I have not had much experiance with it yet as I'm still sorting out bigger issues with the fuel system but my father used it to tear out his asphalt driveway and he said it worked pretty well...
Ahh, I see, it looks like its teed into the bucket curl cyl.
I'd favor an either / or application with a stabilizer cylinder. Combining it wirh the bucket cylinder will reduce the risk of crushing the thumb cylinder, but limit function. Willie