Project
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Project Record: Research
[Chain Tensioner, Sprocket Alignment, and Procedure]
[Version: 1]
[December 6th, 2016]
[Tyler J. Schell]
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Version History
Version
Date
Description/Notes
1
12-05-2016
First Draft
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Table of Contents
Abstract ........................................................................................................................................... 4
Goal ................................................................................................................................................. 4
Primary Heading – Research for Chain Tensioners ........................................................................ 4
Sub-Heading – The Roller Ring Chain Tensioner ...................................................................... 4
Sub-Heading – The Adjustable Chain Tensioner ........................................................................ 5
Sub-Heading – The Floating Chain Tensioner ............................................................................ 7
Sub-Heading – Final Decision for Chain Tensioner ................................................................... 8
Primary Heading – Procedure……………………………………………………………………..9
Conclusion .................................................................................................................................... 16
References ..................................................................................................................................... 17
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Abstract
This project record will consist of the research done to find an appropriate chain tensioner for the
new longer chain, the old chain was too tight on the sprockets, so additional chain links were
added to allow slack in the chain. Because of the addition of more chain links the chain drive
needs a chain tensioner to make up for the slack, there are many ways of tensioning a chain and
the best one that was researched and would work for our chain drive is a floating tensioner by
Snapidle. Also is this report will be how to align the two sprockets so that the chain will be able
to rotate freely without any bends in the chain. The process of aligning the sprockets will be one
of the many steps to properly set of the chain drive so that the dyno will be able to read the
engines output.
Goal
The goal for this project record was to research chain tensioners that would work most efficiently
with the chain drive on the engine. For the chain tensioner to work on the chain, the sprockets
need to be properly aligned and a procedure to set up the chain and tensioner for future
references.
Primary Heading – Research for Chain Tensioners
When the second shaft was first made for the chain drive so that the dyno would be able to read
the output of the engine. The chain was measured to fit snugly on the two sprockets, neither
slack or easy disassembling the chain was taken in account of. This makes the chain to tight on
the two sprockets and a time consuming task to remove the chain from the sprockets. The only
way the chain was able to be removed was to unbolting the four bolts that attach the second
shaft’s ball bearings from the two pillars.
With the appropriate research multiple chain tensioners were found that could be used to tighten
the new chain which is now at a length of 47 chain links. Four different chain tensioners were
found and only one was found to work the best with our chain drive design.
Sub-Heading – The Roller Ring Chain Tensioner
A roller ring as seen in figure 1, is a simple design and would be the easiest to implement into
the chain drive. This is because the plastic ring fits between the two sprockets and within the
chain. The roller ring would then adjust itself to absorb the slack in the chain drive (McMasterCarr).
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Figure 1
(https://www.mcmaster.com/#roller-chain-tensioners/=15cewal)
To see if this design would properly work with our chain drive I contacted a company that
specializes in making roller rings. With all the specifications given to the company they came
back and said that with our system “the speed of our chain drive is too high and the large
sprocket is to large” (roller-ring). So no roller ring would work properly, not even a custom ring
would work for our chain drive.
Sub-Heading – The Adjustable Chain Tensioner
The second and third chain tensioners are both adjustable smaller sprockets but how they are
fastened to the engines base are different. Figure 2 shows that the plate that holds the adjustable
arm is parallel to the sprocket. Without further addition of expanding ways to mount this set up,
the easiest way is to mount the plate on one of the pillars. This would work by fastening the plate
parallel to the chain drive as seen on figure 3, The only problem with this chain tensioner is that
the sprocket would over shoot where the chain would line up. This tensioner is also fairly pricy
estimating about $103 without buying the additional sprocket to tension the chain (McMasterCarr).
Figure 2
(https://www.mcmaster.com/#roller-chain-tensioners/=15cfh1l)
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Figure 3
Sprocket over
shooting
sprockets
The third chain tensioner is similar to the second one, but the place where the bolts fasten the
adjustable chain tensioner are perpendicular to the sprockets as shown in figure 4. This chain
tensioner would sit on the same pillar as the second chain tensioner would but would be placed
on the plane that is perpendicular to the chain as seen in figure 5. This chain tensioner seems to
work because the sprocket would not over shoot the chain like the second chain tensioner, but
not seen on figure 5 the area that the base plate would be fastened to the pillar the bolts would
interfere with the ball bearing system on the opposite side of the pillar (McMaster-Carr).
Figure 4
(https://www.mcmaster.com/#60225k14/=15cfwvz)
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Figure 5
Bolts interfere
with ball bearing
on opposite side
of pillar.
Sub-Heading – The Floating Chain Tensioner
The last chain tensioner that was researched was the floating chain tensioner. This chain
tensioner has two plates that tighten the chain as seen in figure 6. The company that makes this
chain tensioner is the original chain tensioner Snapidle and on their site showed criteria if the
floating chain tensioner would work (McMaster-Carr). These criteria are from figure 7.
Figure 6
(https://www.mcmaster.com/#roller-chain-tensioners/=15cg4x3)
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Figure 7
(http://www.snapidle.com/products/selection-criteria.html)
For the chain drive the large sprocket is 8.68 inches in diameter and the smaller sprocket is 4.10
inches in diameter. The length L = 16.56 inches, so R1 is 2.11 must be less than 4 which it is. R2
is 0.52 which should be less than or equal to 0.5, this number is fairly close but it did not say it
had to be less. R3 was calculated that c has to be smaller than the smaller sprocket, so from the
equation given c should be around 3.485, that is using exactly 0.85 for R3 (Snapidle). With all
the calculations the floating chain drive would be the best suit for the chain drive. The only part
to take in consideration is how fast will the plates wear, because they will constantly be brushing
against the chain.
Sub-Heading – Final Decision for Chain Tensioner
The final decision was carefully reviewing each of the chain tensioners and the only one that
works the best is the Snapidle floating chain tensioner. This would allow the ball bearings and
the second shaft to stay connected to the two pillars, allowing easy removal of the chain. When
removing the chain there is enough slack to take the chain off the teeth of the large sprocket. The
chain cannot be completely removed because how the second shaft is designed so the chain is
able to rest on the smaller sprocket.
To make sure the chain drive meets criteria with how much slack is allowable research was
found that the slack should be 1 percent of the length between the two sprockets. The slack
allowed is roughly 4.2 mm (Ketten Handbuch).
Primary Heading – Procedure
To start the procedure, you will need the following material 7/16th inch, 9/16th inch, 1/8th inch, 17
mm, and 18mm socket wrenches. The fly wheel has three bolt holes as shown in figure 8.
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Figure 8
Gather the base plate along with the bolts and larger washers as seen in figure 9. You will need
the 18 mm socket wrench to tighten the bolts to fasten the base plate to the flywheel. To attach
the base plate, the washers, go between the plate and flywheel and the bolts screw into the
flywheel. Figure 10 shows the bolts slightly screwed into the flywheel. Screw all the bolts evenly
so that the base plate will sit flush on the flywheel. When done hand tightening the bolt take the
18 mm wrench and hold the end of the wrench that fits onto the bolt head and slightly pound on
the end of the handle of the wrench so that the bolts are tightened.
Figure 9
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Figure 10
The next step is to add the large sprocket (figure 11) on to the base plate by the three smaller
holes in the base plate in figure 10. To bolt on the large sprocket a 17 mm socket wrench is
needed to tighten the bolts on to the base plate. The sprocket has 3 smaller washers that sit
between the sprocket and base plate as seen on figure 12. Tighten the bolts the same way as the
bolts on the base plate to the flywheel.
Figure 11
Figure 12
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The third step is to align the two sprockets so that the chain is able to rotate freely on the two
sprockets. You will need to clamps and a long slender beam (figure13) that is long enough to
contact the two sprocket faces. First clamp the beam onto the big sprocket with the clamps
(figure 14).
Figure 13
Figure 14
Adjust the smaller sprocket on the second shaft so that the face of the small sprocket is not
touching the beam that is being extruded from the big sprocket (figure 15).
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Figure 15
Slightly tap the small sprocket closer till the face of the sprocket is flush against the beam (figure
16). If the sprocket is not flush, add washers in-between the ball bearing and pillar till the beam
is flush with the small sprocket.
Figure 16
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Remove the clamps from the big sprocket and rotate the flywheel. Clamp the beam back onto the
big sprocket and see if the beam is flush against the small sprocket. After doing this step multiple
times with rotating the flywheel the sprockets are aligned properly (figure 17). Tighten the two
set screws on the small sprocket with a 1/8th inch allen wrench so that the small sprocket will not
move.
Figure 17
Once the sprockets are aligned place the chain back on the two sprockets as shown in figure 18.
You can also see the slack in the chain, to fix this the Snapidle chain tensioner (figure 19) will be
used to tighten up the chain.
Figure 18
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Figure 19
To add the chain tensioner, first remove the locking nuts with a 7/16th inch wrench. Add the
bottom plate on the tensioner and place on chain as shown in figure 20. Then add the top plate to
the chain tensioner. If the chain is to tight adjust the bottom plate as needed (figure 21). Tighten
all the locking nuts on the tensioner so the plates do not come loose.
Figure 20
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Figure 21
So that the chain tensioner does not rub against the small sprocket (because of gravity and the
chain is on an angle the tensioner moves toward the small sprocket). Tighten the bottom bolt to
the frame so that the tensioner is not as freely to move. Lastly make sure there is at least 1
percent slack present in the chain, you can find this out by placing the bar on the bottom of the
chain and take a measuring device and pull up on the chain to see if the measurement is within
the 1 percent slack ratio (figure 22).
Figure 22
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The complete set up should look as figure 23.
Figure 23
Conclusion
In conclusion, this project record was to research a chain tensioner to adjust the slack within the
chain drive system and a procedure to properly set up the chain drive. The procedure included
how to align the two sprockets after the sprockets were all bolted in their necessary place on the
engine and adjusting the slack in the chain with the Snapidle chain tensioner.
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References
Solidworks: Full assembly of engine to find measurements of sprockets for chain tensioners.
McMaster-Carr:
Chain roller - (https://www.mcmaster.com/#roller-chain-tensioners/=15cewal)
Adjustable Tensioner 1 - (https://www.mcmaster.com/#roller-chain-tensioners/=15cfh1l)
Adjustable Tensioner 2 - (https://www.mcmaster.com/#60225k14/=15cfwvz)
Floating Tensioner - (https://www.mcmaster.com/#roller-chain-tensioners/=15cg4x3)
Snapidle:
(http://www.snapidle.com/products/selection-criteria.html)
Ketten Handbuch: document on chains
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