sickle mower

[jdcrawler]

I'm going to make some drastic changes to the design of the flat belt drive system.
Yesterday, someone on another forum asked about the possibility of putting some sort of dog clutch on the drive pulley on the engine so it could be disengaged from the engine when I wanted to stop the belt.
This would keep the belt on the pulley because the pulley would also be stopped from moving.
With doing that, the belt tensioner could be set to hold pressure on the belt all the time.

It's and interesting idea but not really feasible in this case because the end of the crankshaft is flush with the end of the pulley. The end of the engines crankshaft would have to be sticking out past the pulley far enough to mount the dog clutch assembly on it.


Thinking about this later, I realised that while the dog clutch will not work on the engine pulley, it will work on the shaft under the tractor that goes between the bottom pulley and the right angle gearbox.
I also remembered that I just happen to have the two mating parts for a dog clutch.




So ... with adding the dog clutch to the lower drive shaft, the belt tensioner will no longer engage and disengage the belt.
It is now be set so the belt is engaged all the time.




I have a fixed position, spring loaded rod mounted under the tractor that is connected to the tensioner lever arm.




The other end of this rod slips thru a threaded rod. The spring tension is adjusted by turning the nut on the right end of the threaded rod. Once the tension is set, the threaded rod is locked in place with the a locknut of the left side up against the threaded bracket.
After everything was assembled, I saw that there is room to put the locknut on the right side of the threaded bracket so I'm going to switch that locknut.
This will allow more of the threads on the rod to be holding the spring pressure.




These are the parts to make the dog clutch work :
The two dog clutch halves.
A splined shaft with a splined collar to fit onto it ( parts off a Ford model-T driveshaft and universal joint ).
A clutch throwout bearing fork to move the one side of the dog clutch in and out ( off a Ford model-A ).




One half of the dog clutch will be mounted on the input shaft of the gearbox.




The other half of the dog clutch will have the splined collar fit inside it.




The splined shaft will be fit onto the drive shaft.
A bearing will be fit inside the dog clutch that will be on the gearbox and the end of the drive shaft will fit into it so that the shaft will spin on the bearing when the dog clutch is disengaged.

 

[4getgto]

Ray just thinking will that dog clutch bang into gear or can you ease it in. That gear box may not like clanking into gear. Not sure if I'm following all the way.

 

[jdcrawler]

Ray just thinking will that dog clutch bang into gear or can you ease it in. That gear box may not like clanking into gear. Not sure if I'm following all the way.

Not really " bang " into gear but it will start as soon as the teeth make contact so the engine needs to be on slow idle when it is engaged.
The right angle gearbox is off a mower deck and the mower blade was attached to it. The shock of engaging the dog clutch isn't going to be anywhere near as much of a shock as it would get from the fast spinning mower blades hitting obstacles like sticks and stones..

 

[jdcrawler]

Here you can see that the splined shaft has been braised onto the piece of round bar stock.




I've machined the excess brass out of the grooves.




This allows the collar to slide all the way back now, gaining about 3/4 inch more travel.




I'm not going to use the bearing to hold the end of the splined shaft in place as I had first planned on doing.
I've decided that this whole dog clutch assembly is going to be encased inside a metal box that will hold 90W gear lube.
So instead of using the sealed bearing to hold the spline, I will use a bronze bushing. With everything running in oil, it will work much smoother and last longer than it would out in the open.

I'm going to put a hardened 1/2 inch diameter dowel pin in the end of the spline and it will run inside the bushing.
The splined shaft isn't super hard but it is hard enough that it soon takes the sharp edge off a drill so I'm using end mills to bore the hole for the dowel pin.





The dowel pin is then pressed into the end of the spline.




I pressed a piece of round aluminum inside the dog clutch.
This is being machined out for the bushing to go into it.




The bushing is pressed into the hole.




This half of the clutch fits onto the input shaft of the gearbox.
Once everything is ready for assembly, the shaft will be drilled down thru the holes in the clutch and Split pins will be pressed into them to fasten the clutch to the shaft.




The splined shaft fits into the center of the clutch.

 

[4getgto]

Ray I gotta ask.
What did use to do for a living ? You certainly know your way around making stuff..impressive..!

 

[jdcrawler]

For the other half of the dog clutch, I have this piece of 3 inch diameter steel with a 1-1/2 inch hole in it.
Unforentually, the splined collar is smaller then this hole.




So I'm turning out a steel bushing to fill the gap.




This is pressed into the hole.




And the splined collar is then pressed into it.




The front part of the 3 inch diameter piece has been turned down to fit into the clutch.




A piece of bearing bronze is then turned down.




This is pressed into the other end of the 3 inch piece.




Then the center is bored out.




The splined shaft fits up into the splined collar.




And it slides all the way in so the smooth part rides inside the bronze bushing.
The way the clutch is supported on both ends of the shaft.

 

[jdcrawler]

The part of the throwout bearing that this clutch fork fits onto on the Ford model-A does not spin so there is very little wear on the fork ends when pushing the bearing in and out.




On my situation though, this fork will fit into a groove in that 3 inch diameter piece of steel and it will be spinning all the time. If I leave the clutch fork like it is, it will wear out quickly even with it running in oil. So I have mounted a bearing on the end of each fork to ride against the inside of the groove.




I used a narrow cutoff tool to machine out two grooves.




Then I can use a regular cutting tool to hog out the center area.




Here is the finished groove.




And how the clutch fork will fit into the groove. The groove is about .030 wider than the bearings so only one side of the bearings touches the sides of the groove while it is moving the part in or out.




With the two parts of the clutch fit together on the shaft. This is the maxum open position.
In actual use, the right clutch will only move out 1/8 inch past clearing the end of the left clutch.




And with the clutch engaged.

 

[MNGB]

Very interesting that will work from what I can see

 

[olcowhand]

Not to be offensive Ray, but you don't seem to reply to hardly any questions. We all appreciate your work, and would also appreciate responses to questions.

 

[jdcrawler]

Not to be offensive Ray, but you don't seem to reply to hardly any questions. We all appreciate your work, and would also appreciate responses to questions.

You need to go back thru my posts and you will see that I answer a lot of questions all the time.
I did not answer the question asking what I did for a living because I have been asked that same question over and over and over and I'm tired of answering it !

 

[jdcrawler]

Time to make the box that this clutch assembly will fit into.
This was a shelf that I had made up out of 1/8 inch thick steel some time ago and mounted it under my big bandsaw. It held a plastic tray with a small submersible pump for when I had coolant running on the sawblade.
That was back in the 80's and 90's when I had a part time business of doing pro-street cars and working on other peoples street rods. I took that coolant system off the saw about 30 years ago.

The top two bent over edges are 2-//2 inch wide.




I only need 7 inches of it. Here I have cut thru both sides and I'm now cutting along the bottom panel.




The bottom panel is cut off leaving two 1 inch wide bent over edges.
The two side pieces are turned over and the two 2-1/2 inch wide sections will be welded together to form the bottom.
The top panel will be cut out of the piece that I cut off the bottom that is sitting next to it.




The front end plate is cut out of 1/4 inch thick steel and it is fit to the side of the right angle gear box.




This front panel and one side panel are tack welded together.
A bung has been welded to the side for the oil fill plug and another has been welded to the bottom for the drain plug.




This is mounted back onto the gearbox and the clutch assembly is set in place.




The clutch fork is set up on blocks to where it needs to be positioned.
This is the position with the clutch engaged.




And with the clutch disengaged.
At this point, the location of the pivot on the fork is marked on the inside of the side panel with a center punch.
The hole in the fork is 7/8 inch and my center punch is only 3/4 inch so I had to wrap tape around it until it fit snugly into the fork.




Once the hole is marked, it was drilled out and a piece of round stock was welded to the side panel to hold the bushing.




Here is how it looks from the outside.

 

[jdcrawler]

Ray I gotta ask.
What did use to do for a living ? You certainly know your way around making stuff..impressive..!

I apologize for not answering your question before.

I worked quality control in the machining industry and for about 8 years, I had a part time business at home doing pro-street cars and working on other peoples street rods.

 

[jdcrawler]

With the bushing in place on the one side panel, I can then set the other side panel back up to mark the center for the hole on it.




The hole on this side is machined out larger than the outside of the bushing.
This is so I can machine a part that will hold the bushing with a oil seal on the outside. This part will bolt onto the side panel.
With the hole in the fork being 7/8 diameter and the holes in the bushings and the operating lever being 3/4 diameter, I have to have a way to remove the bushing from one side to be able to get the shaft out.
The bushing on the other side panel will get a cap fastened over it to seal it off.




A center punch pin is set into the hole in the end of the splined shaft.




The end panel is cut out of 1/4 inch thick steel and the center for the hole is marked by hitting it with the hammer.




This hole is also machined out larger than the shaft so it can be easily removed.




The dog clutch housing is welded up.






The welds are ground down and it is primed.

 

[jdcrawler]

The driveshaft for the bottom pulley is fastened into the end of the splined shaft inside the case.




Because this shaft will be rotating whenever the engine is running, I'm going to put a bearing on this end of the gear case.
An aluminum end cap is machined out so the bearing slips into it easily.
The width of the bearing is .010 thicker than the depth of the counterbore that the bearing fits into so the outside of the bearing will be held tightly when this piece is bolted down to the outside of the case.




The other end of this piece has been machined out to have a oil seal pressed into it.




The driveshaft is .748 diameter and the inside of the bearing is .750.
Here I'm knuralising the shaft where the bearing will be to make the shaft larger diameter.
This area measures .759 when finished.




The bearing is pressed onto the shaft.




It is then assembled in the case.

 

[jdcrawler]

This is the position that this will sit in when mounted under the tractor.
This will be the back of the box and the bottom pulley will go on the end of the driveshaft on the left and the sickle mower will attach to the shaft coming out of the right angle gearbox.
The shaft for the engaging fork will come out this hole in the side of the case.




I took a piece of 7/8 inch diameter steel rod and turned down both ends to 3/4 inch diameter.




This fits thru the fork and the shorter 3/4 inch diameter end fits into the bushing on the right side.




Then I machined out a collar to fit on the side of the case.
It has a bronze bushing in one end and the outer end is counterbored for an oil seal to be pressed into it.




This collar slides into the box with just the flange showing on the outside.
The oil seal won't be pressed into it until after the mounting holes have been drill thru the flange and the end of the shaft has a keyway machined into it.




The edge of the 7/8 inch diameter shaft has about .005 clearance between it and the end of the bushing on each side.
Once the fork is fastened to this shaft, this will keep the fork from moving sideways.

 

[jdcrawler]

Final assembly.
There is about 1/4 inch clearance between the teeth with the clutch disengaged.




With the clutch engaged.
The teeth on the dog clutch are case hardened so there's no issue of them ever wearing out or getting gouged up.




This is the front side of the finished unit.
The pipe elbow on the lower left is the oil fill and this sets the oil level in the case.
The top plate has a vent in it.




Left end.




Back side.




And right end.

 

[MNGB]

Looking very professional

 

[jdcrawler]

I'm using a Lovejoy connector between the right angle gearbox and the mower driveshaft.
In preparation of this, I have made up two collars that will fit into the Lovejoy coupler and have a keyway machined into them.




The one collar is threaded on the inside and is screwed onto the output shaft of the gearbox.
This collar has a 1/4 inch hole drilled thru it and a split pin is pressed into it to keep the collar from moving.
Then one half of the coupler is fastened to it.




The other collar with the flange is mounted onto the end of the mower driveshaft with four 1/4 inch cap screws holding it in place.




The other half of the coupler fits onto it.
Because this attachment will have a lot of vibration when it is running, I have used Blue Locktight on the threads of the setscrews on the couplers and on the bolts fastening the flanged collar to the driveshaft.




The mower driveshaft can now be connected to the gearbox.

 

[jdcrawler]

The mower driveshaft is put back into the bearings in the housing.

I'm making a mounting flange to fit on this end and I needed to put the centerpunch all the way thru from the back end to mark where to drill the holes on the flange.
The problem is that the holes on the back end are 3/8 threaded holes and the holes on the front are 7/16 diameter.
So I had to make up a small collar to fit into the 7/16 holes with a hole in the center that the 5/16 diameter centerpunch could fit thru.




Drilling that first hole in the flange.




The flange is put back on with the one bolt holding it in place so I can mark the next hole with the centerpunch.
The vice grip holds the flange tight to the housing.




Once the flange id finished, it is bolted onto the housing.
This is then fit up to the gearbox and side plates are welded on to make it part of the mount for the the gearbox.




Here is the finished mount.




The pulley is mounted on the shaft to complete this unit.




With this part completed and ready to mount back onto the tractor, I decided to go ahead and paint it so I don't have to remove it later to do that.






The mounting bracket and parts that go on the other side of the tractor for this installation.




The underside of that mounting bracket is open for easier access to the couplers.

 

[jdcrawler]

This is the end of the sickle bar that fits onto the mounting bracket.
These two ends fit on the outside of the mounting bracket with pins fitting into the holes so it can pivot up and down.




This is the mounting bracket that the bar fits onto.
As you can see, the sickle bar will not clear the rear wheel when the bar is raised up and the mounting bracket itself will hit the wheel if it is raised up.
This is a modification that I knew I would have to do when I first started measuring for mounting this mower onto the tractor.
It's a simple matter of cutting the two bracket arms that are coming straight out and extending them out further so the wider part of the bracket is out past the wheel.




Before I make this modification though, I want to add a couple of more mounting brackets.
This is an implement that I feel that you can't have too many mounting brackets on it.

The first one is simply a bearing that is bolted to a piece of angle iron.
It is supported from the underside of the frame and fits onto the end of the mower driveshaft.




This bracket is made out of 1/4 inch thick steel.




This fits onto the back of the mower drive housing.