Gear Driven Hydraulic Scarifier System on Boxblade

[3RRL]

So now I had the challange to mount the guide pins to the boxblade at camp. I positioned the scarifiers in the lift plates and jacked them up trying to "center" them so they would move up and down. Then I tack welded the guide pins and hoped for the best. Any machinist will tell you that you are lucky to have them line up square and parallel doing this. Normally I would bore holes to position the guide pins to match the locations of reamed Ø1" holes in the lifter blocks within .001", but had no way to do that.

 

[3RRL]

Well, I got lucky and after beating them around and honing the holes in the plates I got them reasonably close so the lifter bars would slide up and down on the guide pins....phew!

 

[3RRL]

After going through that process for all three lifter blocks I decide to take a break and work on some fun stuff. I welded up some 5/8" thick stock to use as stabilizers for the scarifiers. Then I welded them to the bottom of the boxblade. This also added weight to the boxblade as did the other components. This improvement will reduce the amount of bending and breaking I experiend before. I don't expect the addition to eliminate the problem but wouldn't complain if it did.

 

[3RRL]

My "modified" boxblade was starting to "Beef Up" a bit by now. In the mean time, my wife decide to help me out by priming and painting sime of the other components that were machined. Those long ones are for my backhoe subframe but the rest are all for the boxblade. There are the posts that will hold the gear/rack assembly, wear plates, the lifter bars, the center support for the hydraulic cylinder, and all the side plates that support the rotating shaft.

 

[3RRL]

OK so now I've started to assemble the contraption at the property. What I'm doing here is fitting the racks that will be attached to the hydraulic cylinder to the gears on the shaft. Realizing that I might be of a thousands or two off during this fitting game, all the screw clearance holes are slotted, just in case. As it turned out, because where I ended up welding the various components to the boxblade, I needed every bit of adjustment I had. Some of the boxblade surfaces were bumpy and had knicks and grooves. I was lucky to think of making provisions for it.

 

[3RRL]

That last picture showed clearly the dual driving racks that send rotation to the entire shaft. Here are some of the gears and rack I bought for the project. They ended up being the most expensive items for the project...About $450 for them alone. I was going to make them from scratch but did not have the right gear cutters on hand. I decided to go with 6 pitch, Ø3" pitch diameter, 14-½° pressure angle gears. This allows for dirt and grit without too much interference. I also allowed for an additional .020" clearance between centers in case of a poor fit while assembling at camp.

 

[3RRL]

In that last picture, I ended cutting off the top of the hydraulic cylinder mount I made. I decided to make the center support instead of fastening the cylinder end to one of the boxblade top bolts. There was just not enough travel for the overall length I needed. Plus, I really gobbed the weld on and did not like it much.

So this picture show the welds I made at camp that attach the center support post (for the hydraulic cyl) and also for each of the support bars that hold up the gear/rack assemblies and shaft supports. I used 7018 rod for all the welds. they look a little better.

 

[3RRL]

This picture shows me fitting the same assembly with the hydraulic cylinder mounted. It has a clamp style system where I used ½"-13 socket head cap screws to hold everything in place. Again, I allowed plenty of clearance for fitting adjustments during this proceedure so as to eliminate/reduce any binding up of the system. Again, I was not sure how accurate the welding of the center post to the boxblade would end up.

 

[3RRL]

This is a picture of just the gears, hydraulic cylinder and dual driving racks before I cut off that one end. I made a carrier bar out of Corrax SS and cut pockets for the racks to fit in and then bolted them in place with 3/8 socket head cap screws. I also drilled and tapped the bar 1-1/8-12 thread to screw the cylinder rod into. Finally, I drilled and tapped the center of the rod 3/4-16 and inserted a jam bolt that insures it is locked in place. It is adjustable to get the total stroke of the 4" cylinder so that the cylinder bottoms out in each direction.

 

[3RRL]

Getting near the end of this post, this is a picture of the rippers in the "up" position.