Hey Wardner

Jason the Red · Nov 29, 2011

I remembered you wanted to see some pics of my rotary hoe gearbox that mounted in place of the belt pulley attachment. I pulled it off today, so in the process I flipped it upside down and snapped away! I searched all over for a manufacturer, but could find none. One thing that I did find interesting is that the housing is aluminum.
The large gear goes towards the engine and in case it is not obvious in the pictures, the big gear on the side by itself shares a shaft with the biggest gear on the other side.

Wardner · Nov 30, 2011

Thanks for the pictures.

Not sure what is going on there. I presume the smallest gear is the one that moves under the control of the engagement lever and its axial travel is parallel with the crank centerline.

I suspect that the biggest gear is fixed and meshes with the belt pulley gear. Not sure what the smallest gear meshes with but must be the 4/5th slider. But if that is the case, it seems like it would lock up the transmission.

It would help if we had pictures of it shifted and non-shifted and what it engages. Also a look at the clutch gear to see if it is original to tractor.

Right now I am confused and not able to trace the power flow.

Jason the Red · Nov 30, 2011

This picture is with it disengaged. The entire mechanism moves together through engagement as well as disengagement. When the attachment is disengaged nothing is turning in it. One other thing I don't know if you noticed is there are three gears on the one side, which are constantly meshed. I was originally thinking it could act as a gear reduction of fifth gear, but I don't think that would work.
I will get some pics of the inside of the tractor this afternoon and post back tonight.

Jason the Red · Nov 30, 2011

I took this picture this evening of the belt pulley opening. This was taken with the trans. in neutral.
I measured the distance between the gears on the attachment, which is 1.75 inches. 1.75 inches is also the gap between the the belt pulley gear and fifth gear (when fifth gear is not engaged through the transmission).
With all of that being said, when the attachment is engaged the gears lower down with the big gear mating up with the belt pulley gear and the lowest gear on the opposite side mating up with fifth gear(with the trans. in neutral).

Wardner · Nov 30, 2011

So, it looks like you have a six speed H.

Just wondering if the two middle gears (out of four) could be swapped for a different ratio than what it is set up for now?

Jason the Red · Nov 30, 2011

I don't think they could be due to size constraints. I guess in theory it could happen, but not with this housing.

Janicholson · Nov 30, 2011

Way cool engineering by some bright designer. Does the tractor operate that it has been on?
While it is off could you give us tooth counts of the gears please. Jim

Jason the Red · Dec 1, 2011

The tractor does run and operate, however I am preparing to replace an axle seal and rear axle housing gasket. I figured since I was tearing the tractor down anyway, what was one more part to remove.

I did some more looking this evening, and I've got the numbers you wanted Jim. The large gear that mates with the belt pulley gear is 5.375 inches in diameter (from tip of tooth to tip of tooth)and contains 35 teeth. The gear opposite that one measures 2.5 inches in diameter and has 16 teeth. The next gear in sequence is 3 inches in diameter, and has 19 teeth. Finally the last gear in sequence, and the gear that drives the trans. 5th gear, is 2.25 inches and has 14 teeth.

Owen Aaland · Dec 1, 2011

Is this on an M? If so the ratios are 39/35 35/16 16/14 (the number of teeth on an idler gear does not matter) 14/34. If it on an H the first and last numbers are both 35.

I didn't figure out the actual reduction but it looks like it reduces the speed to about 20 to 25 % of actual speed in R, 1, 2, and 3?

Jason the Red · Dec 2, 2011

It is on an H Owen. You went a little above my pay grade with your calculations, however if you are correct in guessing 20-25 percent reduction in gear speed, that would put fifth gear at about 12mph. Fifth gear is the only gear effected as to use this attachment the tractor"s transmission is left in neutral. Once the attachment is engaged, it transfers power from the belt pulley gear to fifth gear.

Owen Aaland · Dec 2, 2011

I think I had a brain freeze when I made that reply. I was thinking that since the 4/5 gear was in neutral you could chose any of the other gears. That might be true if the transmission were built with shift collars but certainly wouldn't work on an H.

If I did the calculations right the final reduction is 2.1875/1. That would give you a speed of just a little less that half of 5th gear.

Jason the Red · Dec 2, 2011

In your original post I thought you had stated power would be reduced by 20-25 percent.

In my research, the best I can conclude is that this is meant to be used with a rotary hoe. Fifth gear is too fast, and fourth gear is too slow, so this attachment sort of takes up the slack in between the two.

Wardner · Dec 2, 2011

(quoted from post at 01:15:18 12/03/11) I think I had a brain freeze when I made that reply. I was thinking that since the 4/5 gear was in neutral you could chose any of the other gears. That might be true if the transmission were built with shift collars but certainly wouldn't work on an H.

If I did the calculations right the final reduction is 2.1875/1. That would give you a speed of just a little less that half of 5th gear.

Owen, as far as I can tell, there are no idler gears in that attachment. It looks like two sets of compound gears on two different shafts. If the intermediate gears are separated from their companion gear, they could be substituted or reversed for different ratios. Just as long as the total number of teeth on those two gears remain the same.

However, there really can't be any extreme under or over drive with out a double or triple reduction somewhere. H's have two more reductions after the mainshaft but there are somewhat offset by the large tires.

Owen Aaland · Dec 3, 2011

To me it looks like there is one gear in the front and three gears all in the same vertical plane on the back side. In order for the output shaft to rotate the same direction as the input shaft there has to be an odd number of gears in a single plane. The gear tooth count Jason gave was one 35 tooth gear in the front and 16, 19, and 14 in the rear. In order for the output gear, 14 tooth, to rotate the same direction as the input gear, 16 tooth, the middle gear, 19 tooth, must be an idler gear.

The ratios work out to be in the front 35/35. On the back side the ratios are 16/14 with the 19 as an idler gear and 14/35 provided the tractor has the standard 4th gear. Maybe I did the math wrong but I took :

35/35 X 16/14 X 14/35 = 1/1 X 8/7 X 2/5 = 16/35 = 2.1875

D Slater · Dec 3, 2011

(quoted from post at 02:07:21 12/03/11) To me it looks like there is one gear in the front and three gears all in the same vertical plane on the back side. In order for the output shaft to rotate the same direction as the input shaft there has to be an odd number of gears in a single plane. The gear tooth count Jason gave was one 35 tooth gear in the front and 16, 19, and 14 in the rear. In order for the output gear, 14 tooth, to rotate the same direction as the input gear, 16 tooth, the middle gear, 19 tooth, must be an idler gear.

The ratios work out to be in the front 35/35. On the back side the ratios are 16/14 with the 19 as an idler gear and 14/35 provided the tractor has the standard 4th gear. Maybe I did the math wrong but I took :

35/35 X 16/14 X 14/35 = 1/1 X 8/7 X 2/5 = 16/35 = 2.1875

19 teeth looks like the idler gear to me also. Figured this in a hurry and didn't double check but came up with the transmission input shaft turning 1.91 times to the main ahaft 0ne time. That would make the set up speed when engaged around half of 5th gear speed. May double check tonight unless someone corrects me before that.

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