Hydraulic Motor for Chipper Feed

kruszert · Apr 17, 2016

I have a Jinma chipper which has mechanical feed. The feed system is the weak link on this chipper IMO. I just broke the third gearbox after 1 hour chipping - - four inch max branches. At $200 per gearbox I need to do something else! I would like to drive the feed drum using a hydraulic motor. Some of the more expensive chippers use a hydraulic motor feed systems for both a top and bottom feed roller but I will settle for just driving the one drum.

I am hoping to use the hydraulics from my tractor - - I have an extra line not being used. The tractor hydraulic output is 12.5 gpm at 2300 psi. Problem is I need to go slow - - the drum turns around 13.5 rpm. I can stand a little slower but no faster. When I look through the motors (Surplus Center Cat.) they will all go way too fast unless I have some way of reducing flow and most are not rated for the PSI of my system. They do sell adjustable flow controllers but I would have to really limit the flow to get down to the required RPM. I am not even sure if this is good for the motor.

I am not new to building stuff and have set up hydraulic cylinders for a stump grinder but I have never worked with a hydraulic motor. Suggestions would be greatly appreciated.

Thanks,
Reggie

(and yes I know you get what you pay for and on this occasion I am regretting not spending the extra money to get a better chipper

)

aczlan · Apr 17, 2016

Many chippers that use hydraulics from the tractor use flow controllers. Rotary flow dividers will also do this, but they are spendy.
Not sure what a flow controller costs but what about using a small pump that is driven off of the same place that the mechanical drive is?
Alternatively, what about putting in a tee and running two motors in parallel? That would let you use twice as much GPM.
Could also chain drive the feed roller off of the motor with a small sprocket on the motor and a larger one on the roller.

Aaron Z

J_J · Apr 17, 2016

This valve will work to control a hyd motor.

3/8 NPT HYD FLOW CONTROL VALVE W/RELIEF RDRS137-8

I have a similar valve on my PTO circuit.

Hyd motors can run from 0 rpm up the the max motor rpm at whatever psi the load dictates.

Push the lever and control flow and therefore motor rpm.

kruszert · Apr 17, 2016

Thanks for the responses.

J.J. - - I did see that speed reducer and was hoping it would work. With the factory set 1500 psi relief valve it would protect the motor. Does the speed reducer relieve through a separate port that can return to the tractor? I was also concerned about being at the bottom of the motor speed range but I think Aaron's suggestion of a chain drive speed reduction could easily be added with the space I have available. Surplus center has a 24.4 cu in motor for $119.99 so that would get speed down a bunch.

Now to order parts.

Reggie

aczlan · Apr 17, 2016

I would use that motor and a flow divider. Here is how I would plumb it:

For a flow divider, I would use 3/8 NPT HYD FLOW CONTROL VALVE W/RELIEF RDRS137-8 , I would then run it through a selector valve (such as 1 SPOOL 2 GPM HYDAC RM23 HYD CONTROL VALVE chosen only because its a cheap double acting open center valve) which you can tie into your emergency stop bar (you can then use it to reverse the flow and back stuff out when you hit the bar) and into your pump.
You actually only have 7.8GPM available at the rear remotes as 4.7GPM of the "total GPM" is from the power steering pump and is only available for the steering system.

Aaron Z

TMGT · Apr 18, 2016

What about combining the 2? 1 SPOOL 18 GPM MOTOR VALVE W/ FLOW CONTROL

I'm looking at doing somthing similar and this is the valve I was looking at using.

5030 · Apr 18, 2016

I/m curious as to how you 'break' gearboxes. I'm on my original and I have 10 years on it, no issues.

aczlan · Apr 18, 2016

TMGT said:
What about combining the 2? 1 SPOOL 18 GPM MOTOR VALVE W/ FLOW CONTROL
I'm looking at doing somthing similar and this is the valve I was looking at using.

I think that should work if you want to spend a little more money. If you use it for the emergency reversing lever, you will need an adjustable stop for the "feed in" direction but it should have the advantage of letting you do a controlled speed feed in and full speed reverse.

Aaron Z

TMGT · Apr 18, 2016

By the time you buy the additional fittings and hoses I bet the price isn't that different.

aczlan · Apr 18, 2016

TMGT said:
By the time you buy the additional fittings and hoses I bet the price isn't that different.

Looks like $45.89 more to use the all in one valve. For both comparisons, I am assuming that we are running 3/8" NPT lines from the tractor remotes to the valve.

For the separate direction and flow control valves we will need:
2x 12" 3/8 NPT hoses to go from the flow valve to the directional valve - $10.20 - 3/8" X 12" 3/8 NPTM X 3/8 NPTM 3 PSI HYD HOSE
1x 3/8" NPT tee for the excess flow port on the flow control valve - $6.00 - 161-6-6 3/8" TEE
1x 3/8" flow 0-8GPM flow control valve - $93.55 - 3/8 NPT HYD FLOW CONTROL VALVE W/RELIEF RDRS137-8
6x 3/8" NPT to #8 SAE adapters to go into and out of the directional valve and the motor - $3.54
2x #10 SAE to #8 SAE reducers (for the in/out ports on the directional valve) - $11.20 - SAE 1M TO SAE 8F ADAPTER
1x Directional control valve - $59.95 - 1 SPOOL 2 GPM HYDAC RM23 HYD CONTROL VALVE
2x 36" 3/8 NPT hoses to go from the directional valve to the motor- $21.90 - http://www.surpluscenter.com/Hydrau...PTM-X-3-8-NPTM-3000-PSI-HYD-HOSE-903-3836.axd
1x Motor - $119.99 - http://www.surpluscenter.com/Hydrau...55400F3101AAAAA-HYDRAULIC-MOTOR-9-8632-VV.axd
Total cost: $320.33

To use the larger combined directional/flow control valve (which will be more "touchy" as well due to its larger flow range) we will need:
2x 3/8NPT to 3/4" NPT bushing - $4.90 - http://www.surpluscenter.com/Hydrau...ng/3-4-NPT-TO-3-8-NPT-BUSHING-9-5406-12-6.axd
1x directional/flow control valve - $214.60 - http://www.surpluscenter.com/Hydrau...-18-GPM-MOTOR-VALVE-W-FLOW-CONTROL-9-7458.axd
2x 1/2" 36" long hoses - $21.90 - http://www.surpluscenter.com/Hydrau...PTM-X-1-2-NPTM-3000-PSI-HYD-HOSE-905-1236.axd
2x #10 SAE to 1/2 NPT adapter - $4.50 - http://www.surpluscenter.com/Hydrau...ght/SAE-10M-x-1-2-NPTF-SWIVEL-9-6900-10-8.axd
1x motor - $119.99 - http://www.surpluscenter.com/Hydrau...55400F3101AAAAA-HYDRAULIC-MOTOR-9-8632-VV.axd
Total $365.89

Of note: With the combined valve (being as its a motor spool valve), the in-feed rollers will be able to spin relatively freely when the valve is in neutral.
As such, it will be harder to keep the chipper from sucking in a branch if you are trying to just feed a little at a time.

Aaron Z

5030 · Apr 18, 2016

I bet you are right and then there is the added expense of fabrication of a suitable drive scheme (the infeed roller must articulate both vertically and at an angle) so the driveshaft will most likely have to stay in play.

kruszert · Apr 18, 2016

Thanks again for the responses. Aaron thank you, thank you thank you!!!- - the motor, flow divider and control valve are on order. I am curious about the control valve - - would it be an on /off switch or reverser? I was just going to use the flow divider lever to stop the feed drum. As for GPM available I only know what the tractor specs said but 7.8GPM is even better. This may change my chain sprocket teeth but I have room. I am planning to go from the motor to a shaft with large sprocket then to the U-joint drive.

5030 - - now for the chipper story - - you asked for it

. When I first got the chipper the feed drum only had flat 1/8" bars welded across to grab branches. The bars would slide on branches and nothing would feed unless you pushed in constantly - - PITA. I ground notches in the feed drum to make them more like teeth and this worked until I bent the shaft and broke the nut on the drive shaft. I talked to the the dealer that sold me the chipper and nothing else was available so I made a feed drum and sent him a picture (see below) - - I now see that feed drums remarkably similar to mine are now for sale - - wonder where they got the design! Next I broke the nut on the drive shaft - - again. Back to the dealer and found that Jinma had a new design with U joints so I purchased and installed that. Then the bar that holds the feed drum was flexing and bending jamming the feed drum against the side - - gear box gone - - so I remade the entire drum support system using steel tubing - - NO flexing now, goes straight up and down with no problems. At this point I considered trying to design a hydraulic system but I needed the chipper got lazy and ordered another gearbox. I have no idea why this one broke. It was feeding fine, branches were 3.5" max and nothing strange - - it broke in less than an hour of chipping. All gearboxes break by snapping the bronze gear - - the steel worm input is fine. One other change to the chipper was the cutting blades. I found the tips of the "hardened" blades were curling over/bending. I made blades out of D-2 steel had them hardened and I ground them sharp - - blades don't get dull nearly as fast now and they don't bend!

All this sounds like I am a contractor using the chipper constantly but I am not. I bought the chipper around 2008 when I purchased some property with a bunch of pine trees. I chipped branches from around 20 pine trees.
Overall the chipper was fine. I expected to do repairs and stuff when you considered the cost of the chipper. Since then I have been working on some hardwood trees - - around 5 of them and the chipper has not done well. Also, I have never put a 6" branch in the chipper - - 5" has been the max. I try to cut the branches to minimize forks which block the feed drum.

TMGT · Apr 18, 2016

The small price diff. for the combination valve is worth it to me, yes the flow rating will make it a bit touchy (wouldn't have been as bad if it really had the initially stated 12gpm flow) however since it's not controlling a wheel motor and will most likely be used in a steady state a majority of the time I don't see it being an issue.

The valve is also offered with work ports blocked in neutral, but honestly I've never had a problem with the chipper pulling in material, once the feed roller or gearbox is disengaged it stops.

Lots of options, this is just the one I've been contemplating for a while.

kruszert · Apr 18, 2016

You guys are way ahead of me with fittings and hoses. I ordered the main parts just a few minutes ago. After I get an assembly with shaft, sprockets and mounting plate designed and completed I will deal with fittings and hoses.
Thanks again for all the help.

TMGT · Apr 18, 2016

Looking forward to seeing how it turns out, my tractor has a little less flow then yours but should be close enough to compare to your setup.

I actually have another version of the Jinma chipper, I think it's a wc-6, bought it used a few years ago.

Rock knocker · Apr 18, 2016

I hope it's reversible

aczlan · Apr 18, 2016

The valve I linked to should be a FWD - OFF - REV valve (ie: it should work like a standard hydraulic remote).
The downside to stopping the drum with the flow control knob is that you then have 7.8GPM at 1500PSI (or whatever your relief pressure is) worth of heat that your tractor's hydraulic system has to dissipate. That could be problematic if you leave the flow control valve "off" for any length of time.

Aaron Z

5030 · Apr 18, 2016

kruszert said:
Thanks again for the responses. Aaron thank you, thank you thank you!!!- - the motor, flow divider and control valve are on order. I am curious about the control valve - - would it be an on /off switch or reverser? I was just going to use the flow divider lever to stop the feed drum. As for GPM available I only know what the tractor specs said but 7.8GPM is even better. This may change my chain sprocket teeth but I have room. I am planning to go from the motor to a shaft with large sprocket then to the U-joint drive.

5030 - - now for the chipper story - - you asked for it. When I first got the chipper the feed drum only had flat 1/8" bars welded across to grab branches. The bars would slide on branches and nothing would feed unless you pushed in constantly - - PITA. I ground notches in the feed drum to make them more like teeth and this worked until I bent the shaft and broke the nut on the drive shaft. I talked to the the dealer that sold me the chipper and nothing else was available so I made a feed drum and sent him a picture (see below) - - I now see that feed drums remarkably similar to mine are now for sale - - wonder where they got the design! Next I broke the nut on the drive shaft - - again. Back to the dealer and found that Jinma had a new design with U joints so I purchased and installed that. Then the bar that holds the feed drum was flexing and bending jamming the feed drum against the side - - gear box gone - - so I remade the entire drum support system using steel tubing - - NO flexing now, goes straight up and down with no problems. At this point I considered trying to design a hydraulic system but I needed the chipper got lazy and ordered another gearbox. I have no idea why this one broke. It was feeding fine, branches were 3.5" max and nothing strange - - it broke in less than an hour of chipping. All gearboxes break by snapping the bronze gear - - the steel worm input is fine. One other change to the chipper was the cutting blades. I found the tips of the "hardened" blades were curling over/bending. I made blades out of D-2 steel had them hardened and I ground them sharp - - blades don't get dull nearly as fast now and they don't bend!

All this sounds like I am a contractor using the chipper constantly but I am not. I bought the chipper around 2008 when I purchased some property with a bunch of pine trees. I chipped branches from around 20 pine trees.
Overall the chipper was fine. I expected to do repairs and stuff when you considered the cost of the chipper. Since then I have been working on some hardwood trees - - around 5 of them and the chipper has not done well. Also, I have never put a 6" branch in the chipper - - 5" has been the max. I try to cut the branches to minimize forks which block the feed drum.

View attachment 465175

Nice drum, looks like mine.... I have no knife issues at all. Mine are 89 Rockwell, I tested them. I keep a 27 degree included angle and I sharpen them in an angle jig on one of out toolroom grinders... I own the machine shop. I grind them yearly....in the fall.

I've stuff a couple 8" knots in mine. It handles it. Barks a bit...lol Mine must be newer than yours. I've had mine maybe 8 years. Same gearbox, second driveshaft, third belt and 2 sets of knives and bed anvils.

I've found the 27 degree included angle does the best in hardwood. I just ran some old apple trees through it. Everyone wants the chips for smoking...lol

5030 · Apr 18, 2016

I'm going to follow along and see what you come up with and I may convert too. I have 3 sets of remotes on the tractor I use to chip with.

kruszert · Apr 19, 2016

Aaron - - Overheating the oil makes perfect sense - - hadn't thought of that.

I checked the tractor spec book and it says 7.6 gal / min. My 12.5 my number came from the advertising sheet - - should have known they would use the highest number possible. Actually this makes things a little easier - - less reduction required. If my numbers are correct I need to reduce the speed by about 5:1 which will give me around 14.4 rpm at the drum. A little faster than it goes now but I can go that fast for small branches. Likely will use around 13 rpm for most stuff.

Rock - - yes the motor is reversible.

5030 - - 89 Rockwell seems really hard. I made my blades but had them hardened and tempered at a local shop with an oven. They put my small stuff in with other jobs and I think I end up buying the boss lunch for what they charge me. They tested the blades and they are 59 Rockwell C. I used a 40 deg. edge. I was afraid that too sharp would cause the edges to chip - - may have to decrease the angle but that isn't too easy using my old manual feed Brown and Sharp grinder. I have a home shop - - old small stuff by today's standards but I have rebuilt the equipment and everything works fine. If I never have to scrape another way it will be too soon!

The three major parts are on order and should be here in 7 business days. A few days to look through my scrap bin and come up with a design, order some chain and sprockets and start building something. I'll take some pictures along the way but would expect not to have anything for a month - - lots of projects going on for spring! Retirement is wonderful so far - - don't know how I ever had time to work.

Reggie