Lovejoy Couplers

[Ol' Brian]

When I got my log splitter, it had an 075 size Lovejoy coupler on it with the blue urethane spider. That undersize coupler lasted 7 years before it failed completely (the spider failed, unknown to me, and then the jaws eventually wore through). So, I went to the Lovejoy site, and found out that my splitter's engine/pump combination should have had a 095 size coupler at a minimum. So I got the 095 size halves and a black NBR spider (all that the farm store had in stock), and all was well, until today. The NBR spider lasted about 2 years... and failed today. Luckily, the store had more spiders in stock, but they were the black NBR type, and I got back running again in short order.

My question is, does anyone know where you can get the blue urethane spiders, or better yet, one of the "Hytrel" spiders? I figure I've got about 2 years before I'll need it, but might as well start looking now

What size couplers are you guys using on your engine/pumps? You might want to check, as some of the manufacturers might be saving a couple $'s on manufacturing costs by putting undersize Lovejoy couplers on these splitters. My Dad's old Speeco is still on the original Lovejoy coupler and spider from 1975 that is on its 4th engine and 2nd pump... but my Brave seems to be eating Lovejoys up now every couple of years. So, you might want to check what you have on your splitter if you didn't build it yourself to see what you've got, and possibly save yourself some downtime.

Here's Lovejoy's catalog, they have the formulas to calculate what size coupler you need for your application.

Lovejoy

 

[mga]

first, be sure they're aligned properly and both engine and pump mounts are not loose. if they're chewing up, something isn't aligned.

get a couple of the black spyders, as spares for now, you can always order the blue or hytrel on line. also, be sure both couplings are of the same material.

i use the 095 with the black spyder and it's lasted for quite a few years. because i use a vertical shaft engine, i made a tool to align them. i just wrap the couplers with a piece of sheet metal, then tighten that with a radiator hose clamp, then tighten the engine. (an old piston ring compressor steel is perfect for this)



has worked for me.

 

[Suz]

i made a tool to align them. i just wrap the couplers with a piece of sheet metal, then tighten that with a radiator hose clamp, then tighten the engine. (an old piston ring compressor steel is perfect for this)
.

Wow, this is one of those "why didn't I think of that" ideas!! Thanks for posting it because it will work a lot better than the "eyeball" method!

 

[Baldman]

I agree that maybe the alignment is off... hopefully it is that easy of a fix for you.

 

[Ol' Brian]

I was thinking that I might have an alignment issue as well. But, my pump mount is cast aluminum, and mounts to the 4 holes on the back of the engine. The pump then mounts to the other end, and 3 sides of the "square" are totally enclosed, the only access to the LJ coupler is from the bottom as it is currently mounted. I don't know that I have much room for adjustment... the holes are drilled for just a slip through fit on the engine end, and the holes in the pump body are not much larger. But, there might be enough tolerance stacking in this system that it could become an issue.

I'll have to see if I can get a hose clamp around the LJ coupler, tighten it up, then loosen all the mounting bolts, tighten the clamp again, and then carefully tighten the mounting bolts again...

Other than that, I don't know what else I can do, besides building a new pump mount, in case this one is not true... but I don't know if I can build that precisely or not with my tools... you would have to be dead nuts on accurate, and then hope nothing moves when you weld it up.

I was also just wondering if the cold temperatures may have played a part in this... I found one of the legs of the spider laying under the engine... and it seemed to be totally intact, except for where it ripped from the center of the spider. It wasn't too cold today, (yesterday, actually ) but the last time I had the splitter out, it was about 3 degrees... it was COLD... the coldest I have ever run this machine. I'm wondering if the legs, instead of just "squishing" as they provide the dampening effect for the compression/firing pulses, may have cracked instead. That's what looks like may have happened... take a look at this:

As you can see, the legs aren't worn off, instead it looks as if they cracked and broke.

 

[olyman]

doesnt mean anything--that mount may have been machined off at the factory--serious--which is whats tearing up the spider-its just that the nitrile one lasted much longer than the black one--and it takes very little off to tear things up--

 

[merlynr]

trying to get my head around why every other spider leg is ok. misalignment,roughness on one half of LJC, loose screws or key slot or crooked factory groove ??

 

[mga]

you're going to have to reassemble everything, then remove the spark plug and rotate the engine and look at the coupling and how it's mating with the rubber and the other coupling.

check for excessive clearance between all three....maybe one of your couplings walked away from the other.

also, i'd rotate that mount to make getting at the couplings easier. put the opening on top or on the side, if you can.

cold weather shouldn't effect anything...if the couplings were right.

 

[Baldman]

You could always switch it over to this type of bracket...

 

[Ol' Brian]

trying to get my head around why every other spider leg is ok. misalignment,roughness on one half of LJC, loose screws or key slot or crooked factory groove ??

If you look at a Lovejoy coupler, you can see that the power pulse from the engine is only transferred to 3 of the legs. The other 3 would absorb the forces should something try to "drive" the engine. Since the pump has very little rotational inertia, the 3 legs remaining see very little damping requirement, and thus, very little wear/damage.

you're going to have to reassemble everything, then remove the spark plug and rotate the engine and look at the coupling and how it's mating with the rubber and the other coupling.

check for excessive clearance between all three....maybe one of your couplings walked away from the other.

also, i'd rotate that mount to make getting at the couplings easier. put the opening on top or on the side, if you can.

cold weather shouldn't effect anything...if the couplings were right.

Yep, I did all of that as best I could when I put it all back together. As best I can tell through my inspection mirror, everything is as it should be. Everything looks aligned, I couldn't see any problems with alignment. (Granted, it's looking through a mirror.) If anything, I had the 2 hubs too close, as you could see there were witness marks from the opposing jaws on each hub, made when the spider failed. So, I backed off the hub on the pump by about 1/32 of an inch, and tightened it all back up.

Lovejoy says that 1 degree of angular misalignment is acceptable, and up to .015" out of plane... both of which should be visible were they present in this system. I can't see that there is anything near that level of misalignment, but again, I'm looking through a mirror.

I'm still thinking that this is a temperature related issue. Think about it... a single cylinder engine taxes the elastomeric spider fairly severely, as evidenced by the 2.0 service factor applied in the selection formula. Just think about it... take a piece of rubber, get it really cold, and hit it with a hammer. It will shatter like glass. I think that's exactly what happened here... except this piece of rubber got hit with a hammer 1800 times a minute for about 3 hours at less than 10 degrees F.

You could always switch it over to this type of bracket...

That's essentially the type of mount that I have... except mine is "square" instead of round.

 

[Baldman]

But, my pump mount is cast aluminum, and mounts to the 4 holes on the back of the engine. The pump then mounts to the other end, and 3 sides of the "square"

I missed that part dang it!

 

[mga]

If anything, I had the 2 hubs too close, as you could see there were witness marks from the opposing jaws on each hub, made when the spider failed. So, I backed off the hub on the pump by about 1/32 of an inch, and tightened it all back up.

mine are all touching the spyder. backing it off might have caused your problem, since the spyder is inder alot of pressure, it could have folded under the teeth of the hubs.

in fact, when i did align mine, i pushed down on the engine shaft coupling to make sure it was tight against the spyder.

 

[wigglesworth]

This may or may not help. It states that the backing plate on the couplings must be 1" apart. Maybe your smashing the coupling together, causing a deformity. LINK

 

[Ol' Brian]

mine are all touching the spyder. backing it off might have caused your problem, since the spyder is inder alot of pressure, it could have folded under the teeth of the hubs.

in fact, when i did align mine, i pushed down on the engine shaft coupling to make sure it was tight against the spyder.

That's exactly what I did when I assembled this new LJC 2 years ago. There was no room for the spider to move ANYWHERE. In fact, the jaws from the pump hub were touching the face of the engine hub, and the jaws from the engine hub were touching the face of the pump hub. So, when the spider failed, the jaws from each hub made arc shaped witness marks on their respective opposite hub. The jaws should not touch the opposing hub face... there should be no metal to metal contact at all. That's why I backed it off about 1/32 of an inch when I reassembled it yesterday. Before, when I tightened the pump down, it was actually compressing the spider... which probably may have contributed to my problem as well... there was no room for the material to displace to as it functioned.

As far as the jaw-spider-jaw contact, it is snug with the new spider... it took a bit of "finesse" to get the jaws "meshed" into the spider legs.

 

[Ol' Brian]

This may or may not help. It states that the backing plate on the couplings must be 1" apart. Maybe your smashing the coupling together, causing a deformity. LINK

Wiggs, that's for Jaw-in-shear applications. What we have on most all of our log splitters is Jaw-In-Compression.

Totally different.

 

[Curlycherry1]

first, be sure they're aligned properly and both engine and pump mounts are not loose. if they're chewing up, something isn't aligned.

Alignment is critical. They will last practically forever if everything is perfectly aligned.

 

[Maldeney]

How many hours are on the motor and pump?

Your alignment could be spot on but if the clearances are opening up in the pump or motor bearings it won't matter. The shafts will start to move around on you causing a misalignment during operation....


How many hours do you run a year?

We run into this problem alot here at work but they run 24/7. Some run forever and others aonly weeks due to eccentric movement in the shafts.

Just my 2 cents.

 

[Ol' Brian]

How many hours are on the motor and pump?

Your alignment could be spot on but if the clearances are opening up in the pump or motor bearings it won't matter. The shafts will start to move around on you causing a misalignment during operation....


How many hours do you run a year?

We run into this problem alot here at work but they run 24/7. Some run forever and others aonly weeks due to eccentric movement in the shafts.

Just my 2 cents.

Well, that could be also. I think this is my 9th year with this splitter, original engine and pump. How many hours? Wow, good question! I normally split 8-10 cords per year, although this year, I've probably split close to 20, and half of that was a big, tough, knotty Pin Oak... the splitter really got a workout on that tree, all 10 cords we got out of it. It was a BIG tree, 42" dbh. But anyway, it probably takes 3-4 hours to split a full cord, so after a little math... I'd say somewhere in the neighborhood of 350 hours on the engine and pump. But, this LJC/spider was only 2 years old... so I'd say it had about 105 hours on it with the amount of wood I've split since I replaced the original undersized-for-this-application (075 size, but it did have the blue urethane spider) LJC.

I'm thinking that it may have been a combination of things that caused the death of this spider... That big pin oak, having the 2 hubs too close together, causing compression of the spider when the pump was tightened down to the mount, and the extremely cold temperatures the other day while splitting some knotty elm. Add all of those together, and that may equal dead spider.

I picked up a spare spider yesterday also, so I guess I'll just see how long this one lasts. It's not hard to change one out, but it is a little startling to have the spider fail and it sounds just like the connecting rod is trying to exit the engine through the side of the block... wow it makes a racket!! Gives you an idea of what a big job that spider does in there... it does not have an easy life.

 

[Maldeney]

Yeah it tends to be quite disturbing when the couplings go metal to metal!!

It sounds like everything is ready to come apart!:jawdrop:

 

[merlynr]

Here's my pump on homemade splitter going on second year with no problems with ljc