Author Topic: Flat Belt Reversing Mechanism  (Read 4941 times)

Offline Gas_mantle

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Re: Flat Belt Reversing Mechanism
« Reply #15 on: August 03, 2018, 10:59:05 PM »
Thanks Chuck  :)  I wasn't aware that traction engines have 2 or 3 gear ratios to the driving wheels. I just assumed that with the torque of a steam engine and a relatively slow road speed that only one fixed ratio was needed.

Until fairly recently I haven't really given much thought about traction engines but my interest is steadily growing  :)

Offline Brian Rupnow

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Re: Flat Belt Reversing Mechanism
« Reply #16 on: August 03, 2018, 11:32:43 PM »
I found a left over piece of cast iron large enough and long enough to get two 30 tooth gears out of. I like to do all my turning to size and boring the center hole all in one set-up. Tomorrow I will cut both gears at once in one set-up, then part them off as individual gears after all the teeth are cut.

Online crueby

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Re: Flat Belt Reversing Mechanism
« Reply #17 on: August 04, 2018, 12:59:04 AM »
Nice progress on the parts, and interesting about the traction engines, I never knew that they had multiple gear ratios.


 :popcorn:

Offline Brian Rupnow

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Re: Flat Belt Reversing Mechanism
« Reply #18 on: August 04, 2018, 01:49:46 PM »
This morning we get to do the whole thing over again. These two blanks are for the 25 tooth gear. I lucked out this time and found  some 1144 stress proof. Next step will be to mount the rotary table and indexing plates onto the mill and cut some teeth. I might actually drill and tap all the gears for grub screws before I cut the teeth and part them off. I'm not concerned about the 1144 stress proof steel, but cast iron can always be a pig and 'break out' when you are tapping close to the edge.

Offline Brian Rupnow

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Re: Flat Belt Reversing Mechanism
« Reply #19 on: August 04, 2018, 05:52:05 PM »
For those of you who get a thrill looking at gears--Here is a shot of the 30 tooth gears just after being cut. I haven't taken them down and parted them off on the lathe yet. And then in the group picture, the four gears I cut today, and one brass gear that was left over from another project and will become my idler gear on this project


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Offline Ye-Ole Steam Dude

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Re: Flat Belt Reversing Mechanism
« Reply #20 on: August 04, 2018, 06:02:17 PM »
Very nice Brian.

Have a great day,
Thomas

Offline Brian Rupnow

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Re: Flat Belt Reversing Mechanism
« Reply #21 on: August 04, 2018, 08:05:58 PM »
Here is my "tip of the day" for calculating center to center distances for spur gears.---Brian

Online crueby

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Re: Flat Belt Reversing Mechanism
« Reply #22 on: August 04, 2018, 08:57:09 PM »
Great tip!
Since I KNOW that my gears are never perfectly to design, I use a clockmaker-style meshing jig that lets you adjust the spacing till it meshes the way I like, then a point on the axles is used to transfer that to the final plate.
Top view, shows the threaded rod that moves one gear in/out - the gears sit on the shafts in the holder, I have different size bushings for each size axle.

Bottom view, showing the points that transfer the distance to the part. Again, a bushing can be used to sit in one drilled axxle hole to scribe an arc for the next hole.


Offline Gas_mantle

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Re: Flat Belt Reversing Mechanism
« Reply #23 on: August 04, 2018, 09:52:14 PM »
That's a neat meshing jig Chris  :)  It kinda shows that simple ideas can work well and I guess it's the sort of thing that early clockmakers with limited tooling would have used.

I've never cut gears and don't really have any reason to (at least in the foreseeable future) but I do kind of fancy having a go purely to see if I can make a simple meshing pair if I need to. Until I cut a pair of gears or cut a screw thread on my lathe I feel like I'm missing out on something  :(
« Last Edit: August 04, 2018, 10:03:06 PM by Gas_mantle »

Online crueby

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Re: Flat Belt Reversing Mechanism
« Reply #24 on: August 04, 2018, 10:57:40 PM »
That's a neat meshing jig Chris  :)  It kinda shows that simple ideas can work well and I guess it's the sort of thing that early clockmakers with limited tooling would have used.

I've never cut gears and don't really have any reason to (at least in the foreseeable future) but I do kind of fancy having a go purely to see if I can make a simple meshing pair if I need to. Until I cut a pair of gears or cut a screw thread on my lathe I feel like I'm missing out on something  :(
I think the Clickspring site has plans for one. Very handy even for bought gears.

Offline Brian Rupnow

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Re: Flat Belt Reversing Mechanism
« Reply #25 on: August 05, 2018, 02:10:50 PM »
Prompted by J Tiers, I have been doing a lot of thinking on this reversible belt business. I was under the impression that the belt itself stopped and changed direction, and that was my intent with this model, to see if I could replicate this movement. After listening to Jerry's advice and watching a bunch of old sawmill edger and shaping machine videos, the belt doesn't reverse. It is the machinery the driven pulley drives that  has the reverse function built into it. The belt always turns the same direction without stopping, but the fact of shifting the belt from side to side and driving the two different pulleys is where the reverse is happening. This doesn't effect the model at all, except the model will be driven from the end with the single wide pulley on it. Now I'm not certain if I need the center "neutral" pulley or not. I will build the mechanism with this center neutral pulley first, because it is already made. Depending on what happens, I may get rid of the center pulley and just have two pulleys at the driven end. It is the countershaft that reverses direction.

Offline Brian Rupnow

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Re: Flat Belt Reversing Mechanism
« Reply #26 on: August 05, 2018, 04:12:51 PM »
Once a design has been completed for concept, I have to look at what has to be done to make it practical to build. In my case, this means changing the endplates from 1" thick to 3/4" thick, changing the sideplates to 1/2" thick from 3/4" thick, making the endplates an inch higher to move my pulley centers up an inch higher, and adding "foot plates" so I have a means of bolting this thing down. I have made the changes to the model, and pulled detail drawings off the model, so now I can start to build the frame of this machine.

Online Dan Rowe

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Re: Flat Belt Reversing Mechanism
« Reply #27 on: August 05, 2018, 04:53:00 PM »
Brian,
It is not clear what this device is intended to drive, the old line shaft drives did not reverse if it was driving something like a lathe where both directions are required then the system would be like your design. The center idle pully is to turn the lathe off. If it was driving a table saw with no need to reverse the idle pully would still be needed to turn the saw off.

Dan
ShaylocoDan

Offline Brian Rupnow

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Re: Flat Belt Reversing Mechanism
« Reply #28 on: August 05, 2018, 05:06:20 PM »
Good point Dan---I hadn't thought about that.---Brian

Offline Brian Rupnow

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Re: Flat Belt Reversing Mechanism
« Reply #29 on: August 06, 2018, 12:52:30 AM »
It would have been a lovely day to be at the beach----but I wasn't. Wife was having a lazy day---all my grandchildren were spoken for--So, I worked in my shop. Finished the mechanism which shifts the belt side to side. It looks simple, but there are 11 parts there plus 4 circlips.