Model Engine Maker

Engines => Your Own Design => Topic started by: Brian Rupnow on August 02, 2018, 09:17:25 PM

Title: Flat Belt Reversing Mechanism
Post by: Brian Rupnow on August 02, 2018, 09:17:25 PM
With the end of every project, I declare that I've had enough machining, and I'm going to take a break for a couple of months. Then I lay in bed at night, and it isn't sugar plum fairies that dance thru my head---it's machinery!! One of the things that fascinates me is how they shifted flat belts pulleys into reverse on the old lineshaft machinery. I've seen pictures of it but never have seen it done in "real life". I just happen to have a small flat belt, about 5/8" wide x 0.100" thick that I scavenged from somewhere, and time on my hands. So--I spent this morning modelling a flat belt reversing mechanism.   In the attached picture, the power is input to the beige colored counter-shaft in the lower left hand corner. This will make the gear which meshes with it rotate in the opposite direction and carry the green pulley closest to that gear and the shaft it rides on with it. However, the belt is at the other green pulley on the far side from the yellow gear, so what's going on here?
(https://imageshack.com/a/img921/2829/qomwIh.jpg)
Title: Re: Flat Belt Reversing Mechanism
Post by: Brian Rupnow on August 02, 2018, 09:18:47 PM
If we look at the mechanism from the other side, we see that since there is an idler gear between the countershaft gear and the driven pulley gear, the green pulley on the far side will always be rotating in reverse to the first pulley we seen over by the input end of the countershaft. And in the picture as shown, the pulley will be driving the flat belt and the pulley at the far end.
(https://imageshack.com/a/img924/9449/SorzV7.jpg)
Title: Re: Flat Belt Reversing Mechanism
Post by: Brian Rupnow on August 02, 2018, 09:19:45 PM
Now there is a trick here at the end with three pulleys. The center pulley and shaft which it rides on are not driven from either side. The center pulley and shaft just free-wheel. The two outside driven shafts are hollow. The shaft with the center pulley on it is supported by the two outer driven shafts, but it is not keyed to them. The center pulley and it's shaft free-wheel. The second picture posted is actualy a section taken thru the 3-pulley shaft, to show how this is arranged.
(https://imageshack.com/a/img922/2074/9pTxUL.jpg)
(https://imageshack.com/a/img921/6821/iV8nF1.jpg)
Title: Re: Flat Belt Reversing Mechanism
Post by: Brian Rupnow on August 02, 2018, 09:22:16 PM
This picture shows the belt shifted to the center pulley which is the neutral position. Since no power is being transmitted to the shaft which supports the center pulley, the belt will not be driven.
(https://imageshack.com/a/img924/5531/w1Hq32.jpg)
Title: Re: Flat Belt Reversing Mechanism
Post by: Brian Rupnow on August 02, 2018, 09:22:57 PM
So, what mechanism is used to move the belt into one of it's three possible positions? (note that the pulley at the far end has the same overall length as the three shorter pulleys combined) The belt shifter mechanism. This shifter mechanism can be moved by means of a lever, a screw, or even finger power in this case. It is guided in it's travel by matching holes in the two side frames. Since the top run of belt and the bottom run of belt are moving in opposite directions, the bronze colored rollers which contact the sides of the belt must be able to revolve independently, one clockwise, the other counter-clockwise.
(https://imageshack.com/a/img924/8544/dvY8ee.jpg)
Title: Re: Flat Belt Reversing Mechanism
Post by: Brian Rupnow on August 02, 2018, 09:23:40 PM
And here is a final picture, in which the belt has been moved to the opposite side pulley from the very first picture posted, so the belt will be rotating in the opposite direction from the very first picture posted.
(https://imageshack.com/a/img924/6234/T2y4VW.jpg)
Title: Re: Flat Belt Reversing Mechanism
Post by: Brian Rupnow on August 02, 2018, 09:24:31 PM
Will I actually build this?--The answer is "probably".  I never have much "real work" in the summer time, and although my good wife and I have some small day trips planned this summer, that is still going to leave me with a lot of time on my hands.---Brian
Title: Re: Flat Belt Reversing Mechanism
Post by: crueby on August 02, 2018, 10:04:54 PM
Very slick setup, it would be a neat addition to your 90 degree drive unit.
Title: Re: Flat Belt Reversing Mechanism
Post by: Jasonb on August 03, 2018, 06:56:20 AM
Seems a lot of work for what a tumbler reverse would do with far less parts.
Title: Re: Flat Belt Reversing Mechanism
Post by: Brian Rupnow on August 03, 2018, 04:48:05 PM
One of the first things I had to do was to measure the true center to center of the belt when it was on the pulleys. I made up all four of the pulleys this morning, then took two into the machine shop. I zeroed out the quill using my DRO with the long pulley clamped in my vice, then locked the y axis and moved the table in the x axis until I could get the belt on both pulleys. The height of the quill was lowered to match the pulley in the vice. Then it was simply a matter of cranking the table in the X axis until I felt that the belt had proper tension on it. The center to center turned out to be 5.167".
(https://imageshack.com/a/img923/8703/pCsNSj.jpg)
Title: Re: Flat Belt Reversing Mechanism
Post by: Brian Rupnow on August 03, 2018, 07:33:55 PM
One thing about turning--It goes fast.
(https://imageshack.com/a/img923/3945/sG9zqZ.jpg)
Title: Re: Flat Belt Reversing Mechanism
Post by: Dan Rowe on August 03, 2018, 08:08:24 PM
Brian, if the belt stretches after a bit of use the only way to fix it is to add shims to the side plates. If you rearranged the plates you could use slotted holes to allow for belt stretch.

Dan
Title: Re: Flat Belt Reversing Mechanism
Post by: Brian Rupnow on August 03, 2018, 09:37:31 PM
Dan--This thing isn't going to see enough use for the belt to stretch. The belt was salvaged from an old vacuum cleaner with 90,000 miles on it. If it was ever going to stretch it probably happened a long time ago.
Title: Re: Flat Belt Reversing Mechanism
Post by: Gas_mantle on August 03, 2018, 09:48:46 PM
Slightly off topic but going back to the subject of reversing output.

I know little about traction engines but am curious as to how they operated. I appreciate they had the usual Stephenson reversing gear to enable forward or reverse travel but having seen that a lot of engines seem to have spur gears after the crank I was under the impression they could also be reversed through gearing independently of the crank direction ?

Am I missing something here  :headscratch:
Title: Re: Flat Belt Reversing Mechanism
Post by: ChuckKey on August 03, 2018, 10:35:13 PM
I know little about traction engines but am curious as to how they operated. I appreciate they had the usual Stephenson reversing gear to enable forward or reverse travel but having seen that a lot of engines seem to have spur gears after the crank I was under the impression they could also be reversed through gearing independently of the crank direction ?

No. The valve gear does the reversing. The spur gears provide a reduction gear to the wheels.

Typically an agricutural engine will have two speeds and road engines three. It is not a good idea to try to change gear on the move.

Some engines have three shafts (crankshaft, countershaft, and axle) so the wheels turn in the same direction as the flywheel. Others have four shafts so the flywheel and wheels turn in opposite directions.

Pull the pin out of the wheel hub to disconect the drive to use the axle mounted winch drum. Swap the normal pin for a long one to lock the differential.
Title: Re: Flat Belt Reversing Mechanism
Post by: Gas_mantle 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  :)
Title: Re: Flat Belt Reversing Mechanism
Post by: Brian Rupnow 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.
(https://imageshack.com/a/img921/2829/N17hDv.jpg)
Title: Re: Flat Belt Reversing Mechanism
Post by: crueby 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:
Title: Re: Flat Belt Reversing Mechanism
Post by: Brian Rupnow 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.
(https://imageshack.com/a/img923/8257/fRIU1S.jpg)
Title: Re: Flat Belt Reversing Mechanism
Post by: Brian Rupnow 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
(https://imageshack.com/a/img922/7356/UG8hSY.jpg)
(https://imageshack.com/a/img922/5228/nXQzjO.jpg)
.
Title: Re: Flat Belt Reversing Mechanism
Post by: Ye-Ole Steam Dude on August 04, 2018, 06:02:17 PM
Very nice Brian.

Have a great day,
Thomas
Title: Re: Flat Belt Reversing Mechanism
Post by: Brian Rupnow 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
KKiruXkFegA
Title: Re: Flat Belt Reversing Mechanism
Post by: crueby 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.
(https://s5.postimg.cc/pu7udjdmv/IMG_2245.jpg)
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.
(https://s5.postimg.cc/w7wxgsq8n/IMG_2248.jpg)
Title: Re: Flat Belt Reversing Mechanism
Post by: Gas_mantle 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  :(
Title: Re: Flat Belt Reversing Mechanism
Post by: crueby 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.
Title: Re: Flat Belt Reversing Mechanism
Post by: Brian Rupnow 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.
Title: Re: Flat Belt Reversing Mechanism
Post by: Brian Rupnow 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.
(https://imageshack.com/a/img921/4596/hsD7MX.jpg)
Title: Re: Flat Belt Reversing Mechanism
Post by: Dan Rowe 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
Title: Re: Flat Belt Reversing Mechanism
Post by: Brian Rupnow on August 05, 2018, 05:06:20 PM
Good point Dan---I hadn't thought about that.---Brian
Title: Re: Flat Belt Reversing Mechanism
Post by: Brian Rupnow 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.
(https://imageshack.com/a/img922/5043/vPiQhg.jpg)
Title: Re: Flat Belt Reversing Mechanism
Post by: rspringer on August 06, 2018, 06:04:09 AM
You will still need the center idler.  With out it will be like going from forward to reverse with out using a clutch.  The belt will be on counter rotating shafts at the same time.  Kind of like my daughter driving a straight shift, you can force it but it ain't gonan be pretty.
Title: Re: Flat Belt Reversing Mechanism
Post by: Brian Rupnow on August 07, 2018, 12:35:04 AM
One of the major disadvantages of working at "scale model" level, is that some things simply don't scale down that well and still remain functional. I am finished all of the parts for this project except for the end plates that support the shafts.  (I have to buy some material.)  My plan is to manually push or pull the shifter to left or right by hand to see how well the belt moves as I slide it from one pulley to another. On a full size rig, I would have a long lever, pivoted at the bottom and a link from the lever to the end of the slider mechanism. The belt can only be moved from side to side while it is running under power between pulleys. I was able to find this animation on YouTube which is "sorta/kinda" like what I am trying to do, except it isn't reversing.
fM-OMJnaLks
Title: Re: Flat Belt Reversing Mechanism
Post by: Brian Rupnow on August 07, 2018, 01:33:42 PM
-I got some more insight into that neutral center pulley. This set-up was used to drive the cable drum on the carriage of sawmills.  As soon as a board was cut off by the mainsaw you could go quickly from foreword to reverse to retract the carriage. However, when the carriage got to the load end, the belt was moved onto the neutral pulley so the carriage paused while another log was loaded, or the log being cut could be "dogged over" the width of a board and then the belt was moved from the neutral pulley over to the one which advanced the carriage into the saw.--Belts used on a large line shaft driven shaper didn't need a pause at either end of the stroke, so shapers only had a forward and reverse pulley side by side with no neutral pulley between them.---- Brian
Title: Re: Flat Belt Reversing Mechanism
Post by: Dan Rowe on August 07, 2018, 02:16:00 PM
Belts used on a large line shaft driven shaper didn't need a pause at either end of the stroke, so shapers only had a forward and reverse pulley side by side with no neutral pulley between them

Brian, a shaper does not need a reverse but it most defiantly needs an idle pulley to stop the machine. Putting something into the vise on a moving shaper is not something I want to think about.

Dan
Title: Re: Flat Belt Reversing Mechanism
Post by: Brian Rupnow on August 07, 2018, 02:29:09 PM
Okay Dan--Ya got me. Somebody on a different forum had posted a huge flat belt driven shaper. It was wailing back and forth like crazy, driven by a belt which to me appeared to shift between two pulleys only. they must have had some means of disengaging the drive from the shaper, but I didn't see it.---EDI EDIT--There are three pulleys. i just didn't see that before.---Brian
c74bmLsvSU8
Title: Re: Flat Belt Reversing Mechanism
Post by: Kim on August 08, 2018, 05:16:19 AM
Even if you didn't want to stop the machine, it seems like a center 'neutral' pulley would be necessary.  Otherwise, as the belt transitioned from one direction to the other, there would be a not-insignificant amount of time when the belt would be trying to drive both ways at the same time - forward and reverse.  That seems bad.  If nothing else, it would cause excessive wear on the belt because one side or the other (or both) would have to be slipping during the transition.

Just seems like the neutral middle is necessary to me in all cases.

Kim
Title: Re: Flat Belt Reversing Mechanism
Post by: ChuckKey on August 08, 2018, 09:14:20 AM
Pedantry corner: as the table moves rather than the tool, that thing is a planer.
Title: Re: Flat Belt Reversing Mechanism
Post by: Brian Rupnow on August 09, 2018, 02:06:39 AM
Just got home from a great 2 day mini vacation. Wife and I drove over to Peterborough and spent the afternoon telling lies and drinking wine with a good friend I worked with for five years in the zinc die casting business. Him and his wife were great hosts and a good time was had by all.---Now, as to the mechanism--I have thought about the "over center spring loaded toggle" for an automatic reverse function. However, I tried that on a different reversing mechanism using gears and a rack this past year, and it failed rather miserably. If the moving parts had enough momentum to let them coast  the last bit of stroke, the toggle would have worked fine. However, at small scale and relatively light weight, as soon as the toggle was moved almost to the tipping point, the moving components stopped and just sat there.-Fully disengaging one gear from the rack, but not tipping over far enough to engage the reverse turning gear with the rack. I tried many adjustments and refinements of this system, then decided it wasn't going to work. I will do some thinking on Miners quadrant gear solution, but first I have to buy some material tomorrow and finish the two sideplates and assemble this thing to see it work. Sometimes just seeing a new mechanism work will inspire me with solutions to further progress.
Title: Re: Flat Belt Reversing Mechanism
Post by: Steamer5 on August 09, 2018, 02:04:51 PM
Hi Brian,
 Keep at you will crack it!
Thanks for posting the video of the planner, many years ago while visiting a friend at an engineering & foundary works I got to see a planner chomping away on two full length railway rails cutting the taper for points, it was getting towards the end of the cut & from memory was moving a significant distance. This was a rather large machine.

Cheers Kerrin
Title: Re: Flat Belt Reversing Mechanism
Post by: Brian Rupnow on August 10, 2018, 07:53:08 PM
Here we have the first full assembly. I have some serious rework underway with the belt shifting mechanism, and the belt is a little looser than I would have liked, but we are underway.
(https://imageshack.com/a/img922/2524/JtoXxW.jpg)
Title: Re: Flat Belt Reversing Mechanism
Post by: Brian Rupnow on August 10, 2018, 10:14:19 PM
Its hard to tell by looking at a 3D model how big or small something is going to be. The shafts on this thing are only 3/8" cold rolled steel. I just finished getting the gear train all sorted out, and it is working as I had intended. Tomorrow I will remake the belt shifter mechanism. I couldn't get the two 1/4" rods which support the belt shifter any closer to the pulley because the idler gear was in the way. Today I decided to go with an offset belt shifter to keep the side guide rollers as close to the pulley drum as I can get them.
(https://imageshack.com/a/img922/9438/m6UX1F.jpg)
Title: Re: Flat Belt Reversing Mechanism
Post by: zeeprogrammer on August 10, 2018, 10:56:36 PM
I keep  :popcorn:
It's an interesting project...the type that I think will be useful to me at some point.


What's the story on that huge can of e-clips?  ;D
Title: Re: Flat Belt Reversing Mechanism
Post by: Brian Rupnow on August 10, 2018, 11:31:11 PM
Carl--Good question about the e-clips. Ever since I started making model size machinery, e-clips were horrible nasty little things that were hard to hold onto, and hard to install without flying across the room, never to be seen again, or even worse, into your eye. I finally broke down and bought two spring loaded insertion tools and 100 of 1/8" e-clips and 100 3/16" size e-clips. They live in that big cocoa can which is stored on a shelf in my shop unless I actually are using them. The insertion tools are expensive, (about $60 each) and only work on one specific size of e-clip. They are wonderful!!!  I should have bought them ten years ago.
Title: Re: Flat Belt Reversing Mechanism
Post by: Brian Rupnow on August 11, 2018, 12:16:45 AM
It seems to be a bit of an art to get exactly the right center distance between the pulleys. Built as per my original design, the belt is just a bit too slack, and will slip on the pulleys instead of transmitting power. This picture shows the mechanism with four flat washers 0.055" thick between the one endplate and the sideplates, and this seems to make the belt a bit too tight.  I'm starting to feel a bit like Goldilocks. Tomorrow I will try it with some 0.030" spacer washers.
(https://imageshack.com/a/img921/2723/etYziz.jpg)
Title: Re: Flat Belt Reversing Mechanism
Post by: Johnmcc69 on August 11, 2018, 01:12:44 AM
A belt tensioner in the assembly would be slick. Especially if it took the tension off the belt when "shifting" it. Just a thought...

 John
Title: Re: Flat Belt Reversing Mechanism
Post by: Brian Rupnow on August 11, 2018, 01:33:05 AM
John--thanks for having a look and for the suggestion.--What you are suggesting could happen----Brian
Title: Re: Flat Belt Reversing Mechanism
Post by: Johnmcc69 on August 11, 2018, 02:42:05 AM
I'm thinking maybe a lever/spring mounted tensioner that disengaged when you engage the reverse lever. This would take the tension off the belt & make moving the belt easier. Much like disengaging a clutch. Tension on the belts while "driving" & slack while shifting the belt.
Title: Re: Flat Belt Reversing Mechanism
Post by: Brian Rupnow on August 11, 2018, 03:19:36 PM
Here we have a video of the first "run in" of the flat belt reversing system. I do not have the belt shifter installed yet. This is just a run in for half an hour to take any tight spots or binds out of the mechanism. I have to have everything moving very freely before I reach a final decision on center to center of belt pulleys. NOTE THAT IN THE VIDEO I TALK ABOUT A 30 MILLIMETER SPACER--SHOULD HAVE SAID 0.030 THOU.---Brian
6yLrEYt39Tg
Title: Re: Flat Belt Reversing Mechanism
Post by: Brian Rupnow on August 11, 2018, 03:35:43 PM
For those of you who are asking about a crown on the pulleys.---The long single pulley, which is being driven by the flat belt in the video will eventually end up as the "driver", not the driven. The belt has to scoot sideways from one end of the pulley to the other when I shift the belt, so it will not have any crown. The two outer pulleys at the other end MAY have a crown if I determine that they need it. The center pulley at the far end may get a crown, or may not. Before I crown any of the pulleys, I have to build the belt shifting device and install it. It is very possible that the belt shifting mechanism will make the belt hold position so that none of the pulleys require crowns.---Brian
Title: Re: Flat Belt Reversing Mechanism
Post by: Brian Rupnow on August 11, 2018, 03:50:37 PM
I've just had a small surprise---In all the solid models I have posted, you will see that I have the belt shifting mechanism closest to the three individual pulleys. In reality, as per testing just done in the garage, the belt shifts sideways far easier if the shifter mechanism is close to the one long single pulley which is the driver. (I have changed the 6" pulley around to drive the single long pulley since the video was posted.)
Title: Re: Flat Belt Reversing Mechanism
Post by: Brian Rupnow on August 11, 2018, 08:18:47 PM
And---We have a winner. Rather crude set-up and background, but everything works as I had hoped. I will clean things up a bit and post a better video later, but this first run has made my day!!!---Brian
P3UGdEAbdhU
Title: Re: Flat Belt Reversing Mechanism
Post by: Brian Rupnow on August 12, 2018, 12:04:52 AM
Today was a good day. The mechanism works exactly the way I had anticipated. This is the first thing I have built in ages that didn't cost me anything. I had all of the material left over from other projects except for the end plates. I was at a customers, looking at a job, and I happened to mention that my next stop was going to be at a metal suppliers to buy some 4" x 3/4" aluminum. My customer walked over to his rack and gave me a piece of aluminum long enough to get two end plates out of!! I'm not horribly impressed with using a pair of vice grips to move the belt shifter, so I may do something a bit classier there. As far as automating the belt shifter, I don't think I'm going to try to do that. The system doesn't have to transmit a lot of power. I know that belt tension plays into how much power can be transmitted, but my main aim in building this mechanism was to see about the ability to reverse a shaft, not to transmit a lot of power.
Title: Re: Flat Belt Reversing Mechanism
Post by: Brian Rupnow on August 12, 2018, 03:15:55 PM
Now we get to the part I was talking about earlier, where not all things scale down that well. I have proved by my tests yesterday that this mechanism does indeed allow reversing the output from a flat belt. The vice grips were very crude but they did allow me to move the slider to shift the belt. Now I have designed something with a lot more "cool" factor, but it forces me to do some things which are not scalable. My hand which operates the shifter mechanism is "full size", therefore, some of this mechanism has to bridge the gap between miniature and full size. You will see that the end-caps on the shifter rods have been changed to a shape that extends from side to side forming a bridge. Mounted to the top of this bridge is a 2" long piece of 24 dp rack. Meshing with the rack is a gear quadrant with a 6" handle that when inclined 30 degrees to the right or to the left moves the slider thru its full range of movement. The large dark blue piece at one end of the frame is the support for the pivot shaft .
(https://imageshack.com/a/img924/9056/XiqbX6.jpg)
Title: Re: Flat Belt Reversing Mechanism
Post by: Brian Rupnow on August 15, 2018, 04:10:30 PM
I haven't disappeared--I've just taken a short break. I have a friend who, over the years has supplied me with a small fortune in brass angle and brass hex rod. I asked if there was anything I could do for him in return, and he answered that he would like to have a small cable winch to mount under the back of his truck to winch the spare tire up into place. He supplied the aluminum and the gear and pinion and this is what I built for him.
EcngNNqdUso
Title: Re: Flat Belt Reversing Mechanism
Post by: Brian Rupnow on August 16, 2018, 05:35:16 PM
Slowly and somewhat randomly, the changes are happening to put a reversing handle and sector gear on the reversing mechanism, to make it match the most recent 3D model. There is nothing difficult here, just somewhat time consuming. The overhead bridge that will support the gear rack was finished off this morning. The round blue disc is destined to become an 82 tooth gear. I won't cut teeth all the way around it, because I only need a total of 62 degrees to interact with the rack to move my belt shifter from side to side. I find it almost sinful to be doing things in my shop in the middle of such incredibly beautiful weather. My good wife would gladly lay around all day in the air conditioning, but I have to get out and enjoy this weather while it is here. In the middle of January and February its remembering weather like today that keeps me alive until spring. If you are enjoying this thread, give me a shout.---Brian
(https://imageshack.com/a/img924/280/mm2V7y.jpg)
Title: Re: Flat Belt Reversing Mechanism
Post by: Brian Rupnow on August 16, 2018, 07:54:26 PM
HA!!!--Just went out with good wife, oldest son, and second youngest grandson to the Dairy Queen. Banana splits all around. Life is good. Now, back to work on the beast.
Title: Re: Flat Belt Reversing Mechanism
Post by: Brian Rupnow on August 17, 2018, 12:21:23 AM
If any of you think that maybe I'm making this up as I go along---You're absolutely right. I have finished and installed the new bridge that connects to the end of the belt side-shift rods, and mounted a 2 1/2" length of 24 DP gear rack to it. The blue disc which is destined to become a sector gear is attached to a piece of 3/4" diameter cold rolled steel with a 5/16" shoulder bolt. I don't want to take a chance on it spinning while I am cutting gear teeth on it, so I have drilled and pinned it in place with a piece of 1/8" cold rolled steel. You can see the shape it will eventually have scribed on the face of the disc.
(https://imageshack.com/a/img921/5830/93vcaO.jpg)
Title: Re: Flat Belt Reversing Mechanism
Post by: zeeprogrammer on August 17, 2018, 02:04:48 AM
HA!!!--Just went out with good wife, oldest son, and second youngest grandson to the Dairy Queen. Banana splits all around. Life is good. Now, back to work on the beast.

Lucky. I might get the daughters and grand-daughter to go...but not the wife. Which means taking the daughters and grand-daughter may mean personal injury to myself.

Got any Dairy King's in your area? That was the place to go after school. And it was right across the street from school.
Title: Re: Flat Belt Reversing Mechanism
Post by: 10KPete on August 17, 2018, 05:27:19 AM
Right on the corner on the way home from school... man-oh-man I can taste it now....

Good times.

 :cheers:

Pete
Title: Re: Flat Belt Reversing Mechanism
Post by: MJM460 on August 17, 2018, 10:04:00 AM
Hi Brian, I am one of the many enjoying every post on the development of this mechanism.  I never miss it.  Keep up the descriptions of your thought processes and the pictures.  Also looking forward to what you will dream up to drive with it.

MJM460
Title: Re: Flat Belt Reversing Mechanism
Post by: Johnmcc69 on August 17, 2018, 02:08:12 PM
 :popcorn:
I'm enjoying this. Keep it coming!

 John
Title: Re: Flat Belt Reversing Mechanism
Post by: Tennessee Whiskey on August 17, 2018, 04:08:06 PM
You keep on Brian and you’ll have a belt driven GM Powerglide  :ThumbsUp:

Whiskey
Title: Re: Flat Belt Reversing Mechanism
Post by: Brian Rupnow on August 17, 2018, 07:41:21 PM
I have reached the point where if I had one more part I would be finished. I cut the sector gear today, then trimmed away the sides and welded a handle to it. Now I have to make the aluminum pivot support to mount the sector gear and handle on.
(https://imageshack.com/a/img921/8898/QQAKw9.jpg)
Title: Re: Flat Belt Reversing Mechanism
Post by: Brian Rupnow on August 18, 2018, 04:30:49 PM
So here we are with the finished flat belt reversing mechanism being driven by my Philip Duclos designed Hit and Miss engine . The build is a complete success, and I am very happy with it. I'm not sure that I have any real use for it, but it was a challenge to build and I learned a bit along the way.---Brian
FEV-okNoRF0t=5s
(https://imageshack.com/a/img922/5083/5RFnKe.jpg)
Title: Re: Flat Belt Reversing Mechanism
Post by: 10KPete on August 18, 2018, 04:55:24 PM
Pretty slick, Brian. You always have something different and interesting going on.

 :cheers:

Pete
Title: Re: Flat Belt Reversing Mechanism
Post by: Brian Rupnow on August 18, 2018, 06:04:26 PM
Thank you Pete. I do get tired of building engines. Last time I counted, the total was up to either 29 or 30 engines. That includes numerous varieties of air/steam engines, flathead i.c. engines, overhead valve i.c. engines, flame licker engines, and Stirling engines. I like to do something a bit different. Judging by the number of views I have had on this engine, people don't find these strange things I build very interesting, but I find them fascinating and I learn something from every build.---Brian
Title: Re: Flat Belt Reversing Mechanism
Post by: zeeprogrammer on August 18, 2018, 06:52:48 PM
For me, the video is showing as 'unavailable'.
I don't know if anyone else is having this problem.
Title: Re: Flat Belt Reversing Mechanism
Post by: Brian Rupnow on August 18, 2018, 07:05:35 PM
Try it again Zee--I think I fixed it.---Brian
Title: Re: Flat Belt Reversing Mechanism
Post by: zeeprogrammer on August 18, 2018, 07:36:15 PM
Got it. Looks great Brian. Good job  :ThumbsUp:
Title: Re: Flat Belt Reversing Mechanism
Post by: Admiral_dk on August 18, 2018, 08:11:45 PM
Nice result Brian  :ThumbsUp:

I read all post here and include yours. One reason I read them all is that I sometimes learn quite a bit from those that isn't my immediate interest too - so keep on posting as long as you enjoy it too  :cheers:

Best wishes

Per
Title: Re: Flat Belt Reversing Mechanism
Post by: Brian Rupnow on August 18, 2018, 08:20:21 PM
Thank you Zee and Per--It's good to know that people like the strange things I post about.---Brian
Title: Re: Flat Belt Reversing Mechanism
Post by: 10KPete on August 19, 2018, 01:18:33 AM
Engines are wonderful and seeing the ways folks go about designing and building them is very interesting. But nothing but engines can get a bit stale at times. Fortunately there are lot of other areas of engineering to explore and keep things fresh.

 :cheers:

Pete
Title: Re: Flat Belt Reversing Mechanism
Post by: Brian Rupnow on August 19, 2018, 04:42:09 PM
I was having a little bit of trouble with the belt slipping on the smooth face of the three part pulley system. The pulleys are far to small to put any kind of lagging on, so I used a vibrating hand held engraver to make a "pattern" on the face of the two outer pulleys. This fixed the belt slippage completely.
Title: Re: Flat Belt Reversing Mechanism
Post by: Brian Rupnow on August 20, 2018, 11:17:34 PM
One last video before I call it quits. Turn your audio up so you can hear me speaking---I promise it will be funnier!!--Somebody PLEASE let me know if you are able to view the video.--(For some reason I have trouble ensuring that my YouTube videos are set on "public" and not "private".
lPpjrs5x6jct=13s
(https://imageshack.com/a/img924/8760/RhplLS.jpg)
Title: Re: Flat Belt Reversing Mechanism
Post by: zeeprogrammer on August 20, 2018, 11:33:18 PM
Yes. I can see it. Very enjoyable! The universal joint was a nice touch!
Title: Re: Flat Belt Reversing Mechanism
Post by: crueby on August 21, 2018, 12:11:19 AM
Great stuff Brian! :ThumbsUp:
Title: Re: Flat Belt Reversing Mechanism
Post by: Brian Rupnow on August 21, 2018, 05:16:09 PM
This morning, tired of the belt slipping on the driven pulleys, I removed both pulleys and put a full knurl on the face of each one. I left the center (idler) pulley with a plain face. The head pulley is still smooth. I find that although the set-up is great for demonstrating the fact that I can reverse the output shaft by shifting the belt from side to side, it isn't that great if there is much of a torque load on the output shafts. More experimenting this morning showed that sometimes it could drive the funky corner joint mechanism, and sometimes it wouldn't. The engine wouldn't stall out, but the belt would slip on the head pulley about half the time, unless I grabbed one of the wheels on the funky corner joint and "helped " it to get rolling. I think this is purely a result of the vacuum cleaner belt that I am using as my flat belt. Anyways, this has amused me for a couple of weeks, and we've had a bit of fun with it.---Brian
(https://imageshack.com/a/img924/5577/9H1g79.jpg)
Title: Re: Flat Belt Reversing Mechanism
Post by: Craig DeShong on August 28, 2018, 03:34:40 AM
Cool Beans Brian, might have to build one of these myself to give one of my models something to do!      :ThumbsUp: :ThumbsUp: :ThumbsUp: