Go to Post Either you have it hooked up wrong, or you have the Battery of the Gods. Probably filled with Mountain Dew... - nighterfighter [more]
Home
Go Back   Chief Delphi > ChiefDelphi.com Website > Extra Discussion
CD-Media   CD-Spy  
portal register members calendar search Today's Posts Mark Forums Read FAQ rules

 
Reply
Thread Tools Rate Thread Display Modes
  #1   Spotlight this post!  
Unread 03-11-2008, 01:28
Andy L's Avatar
Andy L Andy L is offline
Registered User
FRC #1458
Team Role: Alumni
 
Join Date: Mar 2007
Rookie Year: 2006
Location: Danville
Posts: 348
Andy L has much to be proud ofAndy L has much to be proud ofAndy L has much to be proud ofAndy L has much to be proud ofAndy L has much to be proud ofAndy L has much to be proud ofAndy L has much to be proud ofAndy L has much to be proud ofAndy L has much to be proud of
Send a message via AIM to Andy L
pic: 8020 Chain Tensioning idea

Reply With Quote
  #2   Spotlight this post!  
Unread 03-11-2008, 01:33
AdamHeard's Avatar
AdamHeard AdamHeard is offline
Lead Mentor
FRC #0973 (Greybots)
Team Role: Mentor
 
Join Date: Oct 2004
Rookie Year: 2004
Location: Atascadero
Posts: 5,508
AdamHeard has a reputation beyond reputeAdamHeard has a reputation beyond reputeAdamHeard has a reputation beyond reputeAdamHeard has a reputation beyond reputeAdamHeard has a reputation beyond reputeAdamHeard has a reputation beyond reputeAdamHeard has a reputation beyond reputeAdamHeard has a reputation beyond reputeAdamHeard has a reputation beyond reputeAdamHeard has a reputation beyond reputeAdamHeard has a reputation beyond repute
Send a message via AIM to AdamHeard
Re: pic: 8020 Chain Tensioning idea

Unless those are both COTS pieces I am unaware of, modify most of the pieces substantially to make them easier to produce.

Ideally, make it so as few machining operations as possible are required, and no machine operations are done for no functional reason (the excessive amount of rounds).

Get rid of all the external rounds, especially the one on the bearing bore, that would interefere with it's function,

I would switch both pieces to a solid block with a flange on the bottom for mounting.

Also, the mounting holes look like they would interfere with both the tensioning bolt, and the body of the block.

Your machinist will be happier, and your parts will get done faster with the same functional performance; win-win if you ask me.

Don't take this negatively, your idea is still a good one, the implementation could just use some work.

Last edited by AdamHeard : 03-11-2008 at 01:36.
Reply With Quote
  #3   Spotlight this post!  
Unread 03-11-2008, 01:51
Andy L's Avatar
Andy L Andy L is offline
Registered User
FRC #1458
Team Role: Alumni
 
Join Date: Mar 2007
Rookie Year: 2006
Location: Danville
Posts: 348
Andy L has much to be proud ofAndy L has much to be proud ofAndy L has much to be proud ofAndy L has much to be proud ofAndy L has much to be proud ofAndy L has much to be proud ofAndy L has much to be proud ofAndy L has much to be proud ofAndy L has much to be proud of
Send a message via AIM to Andy L
Re: pic: 8020 Chain Tensioning idea

Thanks for the criticism

I was just kinda messing around with fillets in solidworks, and as my team mate just said to me "dude theyd be so much cooler" I'll probably end up removing them soon.

I'm not sure about the mounting holes, it's something I noticed but I just kinda went through, I may raise up the tensioning bolt hole, I have enough space behind the bearing to do that. If I move it up too high I'll be pulling up on the bearing block also though, right?
Reply With Quote
  #4   Spotlight this post!  
Unread 03-11-2008, 02:18
AdamHeard's Avatar
AdamHeard AdamHeard is offline
Lead Mentor
FRC #0973 (Greybots)
Team Role: Mentor
 
Join Date: Oct 2004
Rookie Year: 2004
Location: Atascadero
Posts: 5,508
AdamHeard has a reputation beyond reputeAdamHeard has a reputation beyond reputeAdamHeard has a reputation beyond reputeAdamHeard has a reputation beyond reputeAdamHeard has a reputation beyond reputeAdamHeard has a reputation beyond reputeAdamHeard has a reputation beyond reputeAdamHeard has a reputation beyond reputeAdamHeard has a reputation beyond reputeAdamHeard has a reputation beyond reputeAdamHeard has a reputation beyond repute
Send a message via AIM to AdamHeard
Re: pic: 8020 Chain Tensioning idea

Quote:
Originally Posted by Andy L View Post
Thanks for the criticism

I was just kinda messing around with fillets in solidworks, and as my team mate just said to me "dude theyd be so much cooler" I'll probably end up removing them soon.

I'm not sure about the mounting holes, it's something I noticed but I just kinda went through, I may raise up the tensioning bolt hole, I have enough space behind the bearing to do that. If I move it up too high I'll be pulling up on the bearing block also though, right?
external rounds do look cool, but unless they are functional or easy to do (as in rounded corners on a plate part), I would leave them off as they are substantially more work.

In the end, well designed simple parts look pretty $@#$@#$@#$@# cool regardless of rounds.

As for the bolt, checking bolt clearances is one of the most important things you can do in design. let me say that again, CHECKING BOLT CLEARANCES IS ONE OF THE MOST IMPORTANT THINGS YOU CAN DO IN DESIGN. You do not want to be the guy everyone on your team is looking at when the multiple-op CNCd part doesn't work because bolt heads collide, and all you had to do is move it 1/8" over initially.

As for moving the bolt up, you could also switch the mounting bolts to flat heads if the flange is thick enough (also check how far the bolt is from the body, the head looks to be hitting the body as well... I'm talking about the imaginary unpictured bolt right now). Yes, moving the bolt up would "pull the block up", but I imagine that force is minimal compared to the clamping force of the bearing blocks mounting bolts.

Also, keep in mind that you don't need that much throw, do the math based on what size chain you are using to see how much it would have to move to change one entire link. That's all the throw you need.
Reply With Quote
  #5   Spotlight this post!  
Unread 03-11-2008, 05:56
cdennisxlx2's Avatar
cdennisxlx2 cdennisxlx2 is offline
Team San Diego Web Liaison
AKA: Cameron Dennis
FRC #1266 (The Devil Duckies)
Team Role: Mentor
 
Join Date: Jan 2005
Rookie Year: 2005
Location: San Diego
Posts: 188
cdennisxlx2 is a splendid one to beholdcdennisxlx2 is a splendid one to beholdcdennisxlx2 is a splendid one to beholdcdennisxlx2 is a splendid one to beholdcdennisxlx2 is a splendid one to beholdcdennisxlx2 is a splendid one to beholdcdennisxlx2 is a splendid one to behold
Re: pic: 8020 Chain Tensioning idea

I would be more worried about the tensioning bolt vibrating loose during game play, if your just going to tap the baring block hole and use a bolt that's a real risk. I would look into making it a straight bore through and using a longer bolt with a nylock nut on the other side, it wont slip and you can tension it just using a nut driver. It would also allow you to keep a more or less even tensioning on all your wheels because you could just easily measure the amount of bolt that's through the nut and make adjustments accordingly on the remaining wheels.
__________________
Team San Diego Robotics Web Liaison
Webmaster and Technical Advisor for the San Diego Regional Planning Committee.
Official Score Keeper for the San Diego Regional
www.sandiegoregional.com
www.frc1266.com
Reply With Quote
  #6   Spotlight this post!  
Unread 03-11-2008, 08:37
Eric O's Avatar
Eric O Eric O is offline
*
AKA: Eric O'Brien
FRC #0177 (Bobcat Robotics)
Team Role: Engineer
 
Join Date: May 2001
Rookie Year: 2000
Location: South Windsor, CT
Posts: 144
Eric O has a reputation beyond reputeEric O has a reputation beyond reputeEric O has a reputation beyond reputeEric O has a reputation beyond reputeEric O has a reputation beyond reputeEric O has a reputation beyond reputeEric O has a reputation beyond reputeEric O has a reputation beyond reputeEric O has a reputation beyond reputeEric O has a reputation beyond reputeEric O has a reputation beyond repute
Send a message via AIM to Eric O Send a message via Yahoo to Eric O
Re: pic: 8020 Chain Tensioning idea

Back when 177 used 80/20, we used to tension axles by actually welding threaded rod onto a slider nut that our bearing block was mounted to and the sliding the whole thing down the slot. You then just put a washer and nut on the rod at the end of the extrusion and tighten down. It’s a similar concept to what you have here, but less complex, and you don't depend on the friction of the slider nuts keep things from sliding. There are a few limitations by doing this. You can’t mount anything from the end to the block, and have to leave some space at the end of the extrusion for the rod to stick out (crucial for fitting in box when doing this on a drive base).
__________________
Eric O'Brien
Team 177 - Bobcat Robotics (00-01,06-?)

Team 229 - Division by Zero - Clarkson University (02-05)
Reply With Quote
  #7   Spotlight this post!  
Unread 03-11-2008, 09:29
JesseK's Avatar
JesseK JesseK is offline
Expert Flybot Crasher
FRC #1885 (ILITE)
Team Role: Mentor
 
Join Date: Mar 2007
Rookie Year: 2005
Location: Reston, VA
Posts: 3,695
JesseK has a reputation beyond reputeJesseK has a reputation beyond reputeJesseK has a reputation beyond reputeJesseK has a reputation beyond reputeJesseK has a reputation beyond reputeJesseK has a reputation beyond reputeJesseK has a reputation beyond reputeJesseK has a reputation beyond reputeJesseK has a reputation beyond reputeJesseK has a reputation beyond reputeJesseK has a reputation beyond repute
Re: pic: 8020 Chain Tensioning idea

To reduce the chance of the tensioner vibrating loose, you could tighten the bearing block down onto the 80/20 after the chain is properly tensioned. This requires bolt clearances though.
__________________

Drive Coach, 1885 (2007-present)
CAD Library Updated 5/1/16 - 2016 Curie/Carver Industrial Design Winner
GitHub
Reply With Quote
  #8   Spotlight this post!  
Unread 03-11-2008, 12:03
Andy L's Avatar
Andy L Andy L is offline
Registered User
FRC #1458
Team Role: Alumni
 
Join Date: Mar 2007
Rookie Year: 2006
Location: Danville
Posts: 348
Andy L has much to be proud ofAndy L has much to be proud ofAndy L has much to be proud ofAndy L has much to be proud ofAndy L has much to be proud ofAndy L has much to be proud ofAndy L has much to be proud ofAndy L has much to be proud ofAndy L has much to be proud of
Send a message via AIM to Andy L
Re: pic: 8020 Chain Tensioning idea

Quote:
Originally Posted by cdennisxlx2 View Post
I would be more worried about the tensioning bolt vibrating loose during game play, if your just going to tap the baring block hole and use a bolt that's a real risk. I would look into making it a straight bore through and using a longer bolt with a nylock nut on the other side, it wont slip and you can tension it just using a nut driver. It would also allow you to keep a more or less even tensioning on all your wheels because you could just easily measure the amount of bolt that's through the nut and make adjustments accordingly on the remaining wheels.
That exact thought occured to me just before I fell asleep, I'll probably end up modifying to do this.
Reply With Quote
  #9   Spotlight this post!  
Unread 03-11-2008, 12:07
Lowfategg's Avatar
Lowfategg Lowfategg is offline
Building cars now....
AKA: Tyler Moser
FRC #2016 (Mighty Monkey Wrenches)
Team Role: Mentor
 
Join Date: Dec 2007
Rookie Year: 2005
Location: Bridgewater, NJ
Posts: 471
Lowfategg has a reputation beyond reputeLowfategg has a reputation beyond reputeLowfategg has a reputation beyond reputeLowfategg has a reputation beyond reputeLowfategg has a reputation beyond reputeLowfategg has a reputation beyond reputeLowfategg has a reputation beyond reputeLowfategg has a reputation beyond reputeLowfategg has a reputation beyond reputeLowfategg has a reputation beyond reputeLowfategg has a reputation beyond repute
Send a message via AIM to Lowfategg
Re: pic: 8020 Chain Tensioning idea

Why not just skip over the bolts and T nuts and just machine a T slot right into piece using something like a woodruff cutter.

Edit: Nvm I think I miss-understood design.
__________________
Mechanical Engineering Student at WPI.

Mightly Monkey Wrenches FRC #2016 - 2010-12 (Mentor)

Past: FTC #74, FVC #3179, FVC #73, FRC #303, FRC #2753
Reply With Quote
  #10   Spotlight this post!  
Unread 03-11-2008, 12:15
rbrown1 rbrown1 is offline
Registered User
AKA: Rex Brown
FRC #1730 (Team Driven)
Team Role: Mentor
 
Join Date: Jul 2006
Rookie Year: 2006
Location: Lee's Summit MO
Posts: 65
rbrown1 has a brilliant futurerbrown1 has a brilliant futurerbrown1 has a brilliant futurerbrown1 has a brilliant futurerbrown1 has a brilliant futurerbrown1 has a brilliant futurerbrown1 has a brilliant futurerbrown1 has a brilliant futurerbrown1 has a brilliant futurerbrown1 has a brilliant futurerbrown1 has a brilliant future
Re: pic: 8020 Chain Tensioning idea

I like the idea. Where you are runing the bolt into the bearing block is that aluminum? If so I would use some type of insert, probably a heli-coil. With this you are less apt to pull the threads out. You can also use locking heli-coils that will reduce the issue with vibration.
Reply With Quote
  #11   Spotlight this post!  
Unread 03-11-2008, 14:59
=Martin=Taylor= =Martin=Taylor= is offline
run the trap!!!
FRC #0100 (The Wild Hat Society)
Team Role: Human Player
 
Join Date: Feb 2006
Rookie Year: 2005
Location: Bezerkeley, California
Posts: 1,255
=Martin=Taylor= has a reputation beyond repute=Martin=Taylor= has a reputation beyond repute=Martin=Taylor= has a reputation beyond repute=Martin=Taylor= has a reputation beyond repute=Martin=Taylor= has a reputation beyond repute=Martin=Taylor= has a reputation beyond repute=Martin=Taylor= has a reputation beyond repute=Martin=Taylor= has a reputation beyond repute=Martin=Taylor= has a reputation beyond repute=Martin=Taylor= has a reputation beyond repute=Martin=Taylor= has a reputation beyond repute
Re: pic: 8020 Chain Tensioning idea

The main reason so many teams have trouble with 80/20 fasteners sliding loose is beucase... of... well its becuase they used the 80/20 fasteners...

Our team takes steel 1/4-20 bolts and grinds the heads so they can fit in the 80/20 grooves. Then we put a lock nut on the top.

If your're too lazy to grind bolts you could also buy these.

One heck of a lot cheaper than 80/20, and it will never come loose.

Or you could just put lock-tite on the 80/20 bolts, but thats a pain.
__________________
"Cooperation; because life is a team sport"
-Philip J. Fry
Reply With Quote
  #12   Spotlight this post!  
Unread 03-11-2008, 15:22
Andy L's Avatar
Andy L Andy L is offline
Registered User
FRC #1458
Team Role: Alumni
 
Join Date: Mar 2007
Rookie Year: 2006
Location: Danville
Posts: 348
Andy L has much to be proud ofAndy L has much to be proud ofAndy L has much to be proud ofAndy L has much to be proud ofAndy L has much to be proud ofAndy L has much to be proud ofAndy L has much to be proud ofAndy L has much to be proud ofAndy L has much to be proud of
Send a message via AIM to Andy L
Re: pic: 8020 Chain Tensioning idea

Quote:
Originally Posted by Hachiban VIII View Post
The main reason so many teams have trouble with 80/20 fasteners sliding loose is beucase... of... well its becuase they used the 80/20 fasteners...

Our team takes steel 1/4-20 bolts and grinds the heads so they can fit in the 80/20 grooves. Then we put a lock nut on the top.

If your're too lazy to grind bolts you could also buy these.

One heck of a lot cheaper than 80/20, and it will never come loose.

Or you could just put lock-tite on the 80/20 bolts, but thats a pain.
I know something we've done simliar to this in the past, but we drilled out the channel so a standard 1/4-20 bolt head would fit in, then we slide it where we need it. This works fairly well with good planning, this is how we're going to bolt down the bearing block.
Reply With Quote
  #13   Spotlight this post!  
Unread 03-11-2008, 16:08
AdamHeard's Avatar
AdamHeard AdamHeard is offline
Lead Mentor
FRC #0973 (Greybots)
Team Role: Mentor
 
Join Date: Oct 2004
Rookie Year: 2004
Location: Atascadero
Posts: 5,508
AdamHeard has a reputation beyond reputeAdamHeard has a reputation beyond reputeAdamHeard has a reputation beyond reputeAdamHeard has a reputation beyond reputeAdamHeard has a reputation beyond reputeAdamHeard has a reputation beyond reputeAdamHeard has a reputation beyond reputeAdamHeard has a reputation beyond reputeAdamHeard has a reputation beyond reputeAdamHeard has a reputation beyond reputeAdamHeard has a reputation beyond repute
Send a message via AIM to AdamHeard
Re: pic: 8020 Chain Tensioning idea

Quote:
Originally Posted by cdennisxlx2 View Post
I would be more worried about the tensioning bolt vibrating loose during game play, if your just going to tap the baring block hole and use a bolt that's a real risk. I would look into making it a straight bore through and using a longer bolt with a nylock nut on the other side, it wont slip and you can tension it just using a nut driver. It would also allow you to keep a more or less even tensioning on all your wheels because you could just easily measure the amount of bolt that's through the nut and make adjustments accordingly on the remaining wheels.
The method of using a bolt to pull a bearing block to tension the chain has been done many times by many teams over many years.

In my past experience with it, if you just check between each match you'll be fine, and it often took a lot more than just once match to radically adjust the tension.

Also, contrary to popular belief, but the resistance to sliding provided by bolting the bearing block down is very minimal compared to the resistance to sliding provided by the tension the tensioner bolt supplies. There is a HUGE mechanical advantage provided by the threads on the bolt.
Reply With Quote
Reply


Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
pic: 6w/d Chain base kajeevan Extra Discussion 9 19-08-2008 22:54
pic: AM Mecanum Chain Drive MrForbes Extra Discussion 5 19-09-2007 02:44
Chain Tensioning Method? David Sherman Technical Discussion 25 26-01-2007 00:39
Axle mounts- Chain tensioning Jeff Sharpe Technical Discussion 12 20-01-2003 22:50
Chain and chain breaker source? kmcclary Off-Season Events 4 22-10-2001 22:51


All times are GMT -5. The time now is 22:39.

The Chief Delphi Forums are sponsored by Innovation First International, Inc.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Copyright © Chief Delphi