Go to Post Although it took me a little while to find my niche in the program, every moment spent has been one great memory after another. - Amanda Morrison [more]
Home
Go Back   Chief Delphi > FIRST > General Forum
CD-Media   CD-Spy  
portal register members calendar search Today's Posts Mark Forums Read FAQ rules

 
Reply
Thread Tools Rating: Thread Rating: 8 votes, 5.00 average. Display Modes
  #151   Spotlight this post!  
Unread 12-12-2013, 14:21
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: 5,529
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: Back for more..VEXpro 2014 Product Unveiling

I would wager they are actually making the claim that HTD is stronger than the traditional trapezoidal tooth, and not gt2. This is just conjecture though.

EDIT: I'm wrong, rewatched video. He was referring to gt2.

Last edited by AdamHeard : 12-12-2013 at 14:55.
Reply With Quote
  #152   Spotlight this post!  
Unread 12-12-2013, 14:32
Andrew Lawrence
 
Posts: n/a
Re: Back for more..VEXpro 2014 Product Unveiling

Quote:
Originally Posted by Chris is me View Post
Could you post more information about your setup? Tooth count of both systems, pulley material, use of tensioners vs exact center, etc. We've had almost the exact opposite experience, but our experience is probably possibly user error rather than an accurate comparison.
We ran a 6wd WCD in the fall to test new ideas for the 2014 season, especially play around with belts. All pulleys had 24 teeth and were made of aluminum pulley stock. We had a tensioning system in place, but rarely had to tension after putting the belts on. It should be made to note that during these tests we added weight to our robot to reach 120 lbs so we could determine a factor of safety for each type of belt. During these weighted tests, we ran full forward, full backward, into walls, and rapid spin turns and reversing spin directions to test the belt reaction. While under lower weight and low risk driving both belts performed equally, however upon testing the heavier robot and heavier driving we found the GT2 belt start to ratchet, while the HTD belt stayed in place.
Reply With Quote
  #153   Spotlight this post!  
Unread 12-12-2013, 14:47
Chris is me's Avatar
Chris is me Chris is me is offline
no bag, vex only, final destination
AKA: Pinecone
FRC #0228 (GUS Robotics); FRC #2170 (Titanium Tomahawks)
Team Role: Mentor
 
Join Date: Dec 2008
Rookie Year: 2006
Location: Glastonbury, CT
Posts: 7,797
Chris is me has a reputation beyond reputeChris is me has a reputation beyond reputeChris is me has a reputation beyond reputeChris is me has a reputation beyond reputeChris is me has a reputation beyond reputeChris is me has a reputation beyond reputeChris is me has a reputation beyond reputeChris is me has a reputation beyond reputeChris is me has a reputation beyond reputeChris is me has a reputation beyond reputeChris is me has a reputation beyond repute
Send a message via AIM to Chris is me
Re: Back for more..VEXpro 2014 Product Unveiling

Quote:
Originally Posted by Andrew Lawrence View Post
We ran a 6wd WCD in the fall to test new ideas for the 2014 season, especially play around with belts. All pulleys had 24 teeth and were made of aluminum pulley stock. We had a tensioning system in place, but rarely had to tension after putting the belts on. It should be made to note that during these tests we added weight to our robot to reach 120 lbs so we could determine a factor of safety for each type of belt. During these weighted tests, we ran full forward, full backward, into walls, and rapid spin turns and reversing spin directions to test the belt reaction. While under lower weight and low risk driving both belts performed equally, however upon testing the heavier robot and heavier driving we found the GT2 belt start to ratchet, while the HTD belt stayed in place.
Did you adjust tension between belt changes?

What width were the belts?

Did you use different pulleys or the same type? Which kind?
__________________
Mentor / Drive Coach: 228 (2016-?)
--2016 Waterbury SFs (with 3314, 3719), RIDE #2 Seed / Winners (with 1058, 6153), Carver QFs (with 503, 359, 4607)
Mentor / Consultant Person: 2170 (2017-?)
.
College Mentor: 2791 (2010-2015)
-- 2015 TVR Motorola Quality, FLR GM Industrial Design -- 2014 FLR Motorola Quality / SFs (with 341, 4930)
-- 2013 BAE Motorola Quality, WPI Regional #1 Seed / Delphi Excellence in Engineering / Finalists (with 20, 3182)
-- 2012 BAE Imagery / Finalists (with 1519, 885), CT Xerox Creativity / SFs (with 2168, 118)
Student: 1714 (2009) - 2009 MN 10K Lakes Regional Winners (with 2826, 2470)
2791 Build Season Photo Gallery - Look here for mechanism photos My Robotics Blog (Updated April 11 2014)
Reply With Quote
  #154   Spotlight this post!  
Unread 12-12-2013, 14:55
Andrew Lawrence
 
Posts: n/a
Re: Back for more..VEXpro 2014 Product Unveiling

Quote:
Originally Posted by Chris is me View Post
Did you adjust tension between belt changes?

What width were the belts?

Did you use different pulleys or the same type? Which kind?
The tension was the same on both HTD and GT2, and to compensate for any discrepancies we tried both belts multiple times, switching out between rounds.

The belts were 9mm wide, 5mm pitch.

All pulleys were the same aluminum 24 tooth cut from the same stock, all the same width.
Reply With Quote
  #155   Spotlight this post!  
Unread 12-12-2013, 15:00
Chris is me's Avatar
Chris is me Chris is me is offline
no bag, vex only, final destination
AKA: Pinecone
FRC #0228 (GUS Robotics); FRC #2170 (Titanium Tomahawks)
Team Role: Mentor
 
Join Date: Dec 2008
Rookie Year: 2006
Location: Glastonbury, CT
Posts: 7,797
Chris is me has a reputation beyond reputeChris is me has a reputation beyond reputeChris is me has a reputation beyond reputeChris is me has a reputation beyond reputeChris is me has a reputation beyond reputeChris is me has a reputation beyond reputeChris is me has a reputation beyond reputeChris is me has a reputation beyond reputeChris is me has a reputation beyond reputeChris is me has a reputation beyond reputeChris is me has a reputation beyond repute
Send a message via AIM to Chris is me
Re: Back for more..VEXpro 2014 Product Unveiling

Quote:
Originally Posted by Andrew Lawrence View Post
All pulleys were the same aluminum 24 tooth cut from the same stock, all the same width.
GT2 pulley stock is different than HTD pulley stock, which is different than regular timing belt stock. I don't think it's fair to compare belt performance when at least one of the belts is running on a pulley it wasn't designed to run on.
__________________
Mentor / Drive Coach: 228 (2016-?)
--2016 Waterbury SFs (with 3314, 3719), RIDE #2 Seed / Winners (with 1058, 6153), Carver QFs (with 503, 359, 4607)
Mentor / Consultant Person: 2170 (2017-?)
.
College Mentor: 2791 (2010-2015)
-- 2015 TVR Motorola Quality, FLR GM Industrial Design -- 2014 FLR Motorola Quality / SFs (with 341, 4930)
-- 2013 BAE Motorola Quality, WPI Regional #1 Seed / Delphi Excellence in Engineering / Finalists (with 20, 3182)
-- 2012 BAE Imagery / Finalists (with 1519, 885), CT Xerox Creativity / SFs (with 2168, 118)
Student: 1714 (2009) - 2009 MN 10K Lakes Regional Winners (with 2826, 2470)
2791 Build Season Photo Gallery - Look here for mechanism photos My Robotics Blog (Updated April 11 2014)
Reply With Quote
  #156   Spotlight this post!  
Unread 12-12-2013, 15:02
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: 5,529
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: Back for more..VEXpro 2014 Product Unveiling

Quote:
Originally Posted by Chris is me View Post
GT2 pulley stock is different than HTD pulley stock, which is different than regular timing belt stock. I don't think it's fair to compare belt performance when at least one of the belts is running on a pulley it wasn't designed to run on.
These two links help compare that a little bit;
http://www.gates.com/brochure.cfm?br...cation_id=3881
http://www.gates.com/brochure.cfm?br...cation_id=3881
Reply With Quote
  #157   Spotlight this post!  
Unread 12-12-2013, 15:04
sdcantrell56's Avatar
sdcantrell56 sdcantrell56 is online now
Registered User
AKA: Sean
FRC #2415 (Wired Cats)
Team Role: Mentor
 
Join Date: Jan 2006
Rookie Year: 2004
Location: Atlanta, GA
Posts: 1,038
sdcantrell56 has a reputation beyond reputesdcantrell56 has a reputation beyond reputesdcantrell56 has a reputation beyond reputesdcantrell56 has a reputation beyond reputesdcantrell56 has a reputation beyond reputesdcantrell56 has a reputation beyond reputesdcantrell56 has a reputation beyond reputesdcantrell56 has a reputation beyond reputesdcantrell56 has a reputation beyond reputesdcantrell56 has a reputation beyond reputesdcantrell56 has a reputation beyond repute
Re: Back for more..VEXpro 2014 Product Unveiling

Quote:
Originally Posted by Andrew Lawrence View Post
The tension was the same on both HTD and GT2, and to compensate for any discrepancies we tried both belts multiple times, switching out between rounds.

The belts were 9mm wide, 5mm pitch.

All pulleys were the same aluminum 24 tooth cut from the same stock, all the same width.
I'm going to guess the pulley stock was HTD?
__________________

Mentor 2415
Reply With Quote
  #158   Spotlight this post!  
Unread 12-12-2013, 15:14
Patrick Flynn Patrick Flynn is offline
Registered User
no team
Team Role: Alumni
 
Join Date: Mar 2012
Rookie Year: 2010
Location: Churchville Ny
Posts: 178
Patrick Flynn has a reputation beyond reputePatrick Flynn has a reputation beyond reputePatrick Flynn has a reputation beyond reputePatrick Flynn has a reputation beyond reputePatrick Flynn has a reputation beyond reputePatrick Flynn has a reputation beyond reputePatrick Flynn has a reputation beyond reputePatrick Flynn has a reputation beyond reputePatrick Flynn has a reputation beyond reputePatrick Flynn has a reputation beyond reputePatrick Flynn has a reputation beyond repute
Re: Back for more..VEXpro 2014 Product Unveiling

Quote:
Originally Posted by JVN View Post
Hi Sean,
Unfortunately, I don't have a data sheet to back this up. We spoke directly with a few belt manufacturers, off the record on this topic.

Of course those users who would prefer GT2 belts can purchase them from any number of suppliers. VEXpro has chosen HTD based on the feedback we received, and some simple preliminary testing.

If you have any concerns, feel free to email prosupport@vex.com to discuss further.

-John
I've done some searching on this claim and it seems difficult to directly find information to back it up, but using the information here, http://www.transdev.co.uk/catalogues...pretension.pdf

And making the assuming that a lower required belt preload for the same transmitted power would mean that the belt would be less likely to ratchet.
This is a pretty safe assumption because the preload is the belt tension needed to maintain contact given a transmitted power so lower preload better the teeth are at self maintaining contact.
Quote:
FP =[( P*k*10^5)/(n*d0)]+f0*b*(It/Lb)
Now assuiming that all factors are the same except k and f0, these are the properties derived from the belt tooth structure.

Looking on the website and at the offered belt profiles they do not offer exactly GT2 and HTD belts so i picked similar profiles, XL for GT2 and 5M for HTD.
Profiles can be seen here, http://www.transdev.co.uk/pages/belt...prene_main.htm
Quote:
P=10Kw
n=1000rpm
d0=10mm
b=5mm
It=29.4mm
Lb=1

[GT2~XL] Fp=1051.45
[HTD~5M] Fp=429.4
This would support the claim that a HTD profile would be much less likely to ratchet as it requires a lower preload to maintain tooth contact at a given transmitted load.
__________________
Reply With Quote
  #159   Spotlight this post!  
Unread 12-12-2013, 15:36
apples000's Avatar
apples000 apples000 is offline
Registered User
no team
 
Join Date: Mar 2012
Rookie Year: 2012
Location: United States
Posts: 222
apples000 has a brilliant futureapples000 has a brilliant futureapples000 has a brilliant futureapples000 has a brilliant futureapples000 has a brilliant futureapples000 has a brilliant futureapples000 has a brilliant futureapples000 has a brilliant futureapples000 has a brilliant futureapples000 has a brilliant futureapples000 has a brilliant future
Re: Back for more..VEXpro 2014 Product Unveiling

A few of the cad models are messed up. The color of the models was a nice addition, but the wrong parts are used sometimes, especially in the shafts for the gearboxes. Often times they are too long and go through a motor. See the 3 CIM PTO box.

I'm also confused by the wcp 3 cim pto design. It's much thicker than it needs to be. To begin with, the distance the shifting dog travels is about twice what it needs to be. A quick reconfigure of the design let me slim the gearbox down by 1.25". There's a ton of wasted space. Also, the outer plate needs to hold 3 bearings, 4 standoff mounts, and 4 cylinder mounts, yet it has spots for mounting the CIMS. Again, this could be make significantly smaller.

I'll post a picture of what i'm talking about in an hour or so.
Reply With Quote
  #160   Spotlight this post!  
Unread 12-12-2013, 15:42
Steven Donow Steven Donow is offline
Registered User
AKA: Scooby
no team
Team Role: College Student
 
Join Date: Apr 2010
Rookie Year: 2009
Location: Boston, MA
Posts: 1,335
Steven Donow has a reputation beyond reputeSteven Donow has a reputation beyond reputeSteven Donow has a reputation beyond reputeSteven Donow has a reputation beyond reputeSteven Donow has a reputation beyond reputeSteven Donow has a reputation beyond reputeSteven Donow has a reputation beyond reputeSteven Donow has a reputation beyond reputeSteven Donow has a reputation beyond reputeSteven Donow has a reputation beyond reputeSteven Donow has a reputation beyond repute
Re: Back for more..VEXpro 2014 Product Unveiling

Quote:
Originally Posted by apples000 View Post
A few of the cad models are messed up. The color of the models was a nice addition, but the wrong parts are used sometimes, especially in the shafts for the gearboxes. Often times they are too long and go through a motor. See the 3 CIM PTO box.

I'm also confused by the wcp 3 cim pto design. It's much thicker than it needs to be. To begin with, the distance the shifting dog travels is about twice what it needs to be. A quick reconfigure of the design let me slim the gearbox down by 1.25". There's a ton of wasted space. Also, the outer plate needs to hold 3 bearings, 4 standoff mounts, and 4 cylinder mounts, yet it has spots for mounting the CIMS. Again, this could be make significantly smaller.

I'll post a picture of what i'm talking about in an hour or so.
If I'm not mistaken, the distance between the gear and the PTO is probably to allow versatility in adding Versahubs/Versapulleys; ie, you're not restricted to using pulleys of a certain thickness/can use multiple pulleys/sprockets.
Reply With Quote
  #161   Spotlight this post!  
Unread 12-12-2013, 15:44
Akash Rastogi Akash Rastogi is offline
Jim Zondag is my Spirit Animal
FRC #2170 (Titanium Tomahawks)
Team Role: Mentor
 
Join Date: Feb 2007
Rookie Year: 2006
Location: Manchester, Connecticut
Posts: 7,009
Akash Rastogi has a reputation beyond reputeAkash Rastogi has a reputation beyond reputeAkash Rastogi has a reputation beyond reputeAkash Rastogi has a reputation beyond reputeAkash Rastogi has a reputation beyond reputeAkash Rastogi has a reputation beyond reputeAkash Rastogi has a reputation beyond reputeAkash Rastogi has a reputation beyond reputeAkash Rastogi has a reputation beyond reputeAkash Rastogi has a reputation beyond reputeAkash Rastogi has a reputation beyond repute
Re: Back for more..VEXpro 2014 Product Unveiling

Quote:
Originally Posted by apples000 View Post
A few of the cad models are messed up. The color of the models was a nice addition, but the wrong parts are used sometimes, especially in the shafts for the gearboxes. Often times they are too long and go through a motor. See the 3 CIM PTO box.

I'm also confused by the wcp 3 cim pto design. It's much thicker than it needs to be. To begin with, the distance the shifting dog travels is about twice what it needs to be. A quick reconfigure of the design let me slim the gearbox down by 1.25". There's a ton of wasted space. Also, the outer plate needs to hold 3 bearings, 4 standoff mounts, and 4 cylinder mounts, yet it has spots for mounting the CIMS. Again, this could be make significantly smaller.

I'll post a picture of what i'm talking about in an hour or so.
Are you talking about the space that holds sprockets for chain or belts, or something else? Plus, what Steven said.

Parallel symmetrical plates allow for quicker and more efficient fabrication, I would imagine.
__________________
My posts and opinions do not necessarily reflect those of my affiliated team.
['16-'xx]: Mentor FRC 2170 | ['11-'13]: Co-Founder/Mentor FRC 3929 | ['06-'10]: Student FRC 11 - MORT | ['08-'12]: Founder - EWCP (OG)
Reply With Quote
  #162   Spotlight this post!  
Unread 12-12-2013, 15:52
apples000's Avatar
apples000 apples000 is offline
Registered User
no team
 
Join Date: Mar 2012
Rookie Year: 2012
Location: United States
Posts: 222
apples000 has a brilliant futureapples000 has a brilliant futureapples000 has a brilliant futureapples000 has a brilliant futureapples000 has a brilliant futureapples000 has a brilliant futureapples000 has a brilliant futureapples000 has a brilliant futureapples000 has a brilliant futureapples000 has a brilliant futureapples000 has a brilliant future
Re: Back for more..VEXpro 2014 Product Unveiling

Here's what I'm talking about. I got the gearbox slimmer by 1" (3.5" to 2.5"), and switched the standoffs to screws in the CIM mounting holes. My design doesn't have bearings, but you get the idea.
Attached Thumbnails
Click image for larger version

Name:	before.JPG
Views:	128
Size:	83.7 KB
ID:	15543  Click image for larger version

Name:	after.JPG
Views:	142
Size:	63.9 KB
ID:	15544  
Reply With Quote
  #163   Spotlight this post!  
Unread 12-12-2013, 15:53
Akash Rastogi Akash Rastogi is offline
Jim Zondag is my Spirit Animal
FRC #2170 (Titanium Tomahawks)
Team Role: Mentor
 
Join Date: Feb 2007
Rookie Year: 2006
Location: Manchester, Connecticut
Posts: 7,009
Akash Rastogi has a reputation beyond reputeAkash Rastogi has a reputation beyond reputeAkash Rastogi has a reputation beyond reputeAkash Rastogi has a reputation beyond reputeAkash Rastogi has a reputation beyond reputeAkash Rastogi has a reputation beyond reputeAkash Rastogi has a reputation beyond reputeAkash Rastogi has a reputation beyond reputeAkash Rastogi has a reputation beyond reputeAkash Rastogi has a reputation beyond reputeAkash Rastogi has a reputation beyond repute
Re: Back for more..VEXpro 2014 Product Unveiling

Quote:
Originally Posted by apples000 View Post
Here's what I'm talking about. I got the gearbox slimmer by 1" (3.5" to 2.5"), and switched the standoffs to screws in the CIM mounting holes. My design doesn't have bearings, but you get the idea.
lol

I think you ought to read the product description again. That configuration is intended for a typical WCD setup. That is why there is a space for your sprockets.




.
__________________
My posts and opinions do not necessarily reflect those of my affiliated team.
['16-'xx]: Mentor FRC 2170 | ['11-'13]: Co-Founder/Mentor FRC 3929 | ['06-'10]: Student FRC 11 - MORT | ['08-'12]: Founder - EWCP (OG)

Last edited by Akash Rastogi : 12-12-2013 at 15:55.
Reply With Quote
  #164   Spotlight this post!  
Unread 12-12-2013, 15:53
Aren_Hill's Avatar
Aren_Hill Aren_Hill is offline
Build Nifty Things
no team
Team Role: Mentor
 
Join Date: Feb 2005
Rookie Year: 2005
Location: Menlo Park CA
Posts: 1,219
Aren_Hill has a reputation beyond reputeAren_Hill has a reputation beyond reputeAren_Hill has a reputation beyond reputeAren_Hill has a reputation beyond reputeAren_Hill has a reputation beyond reputeAren_Hill has a reputation beyond reputeAren_Hill has a reputation beyond reputeAren_Hill has a reputation beyond reputeAren_Hill has a reputation beyond reputeAren_Hill has a reputation beyond reputeAren_Hill has a reputation beyond repute
Re: Back for more..VEXpro 2014 Product Unveiling

Quote:
Originally Posted by apples000 View Post
A few of the cad models are messed up. The color of the models was a nice addition, but the wrong parts are used sometimes, especially in the shafts for the gearboxes. Often times they are too long and go through a motor. See the 3 CIM PTO box.

I'm also confused by the wcp 3 cim pto design. It's much thicker than it needs to be. To begin with, the distance the shifting dog travels is about twice what it needs to be. A quick reconfigure of the design let me slim the gearbox down by 1.25". There's a ton of wasted space. Also, the outer plate needs to hold 3 bearings, 4 standoff mounts, and 4 cylinder mounts, yet it has spots for mounting the CIMS. Again, this could be make significantly smaller.

I'll post a picture of what i'm talking about in an hour or so.
The PTO Kit reuses many existing parts, including the main output shaft, this would typically be cut off where it meets the opposite plate. Rather than creating slightly tweaked versions of a bunch of existing parts we chose to repurpose existing things.

Also space is required for the gear/sprocket/pulley attached to the Versadog, Hence why this kit is listed as an option to only work with the WCD version of the 3 CIM DS.
__________________
A guy who likes robots.
1625->3928->148->1296->971 oh dear
Reply With Quote
  #165   Spotlight this post!  
Unread 12-12-2013, 15:56
apples000's Avatar
apples000 apples000 is offline
Registered User
no team
 
Join Date: Mar 2012
Rookie Year: 2012
Location: United States
Posts: 222
apples000 has a brilliant futureapples000 has a brilliant futureapples000 has a brilliant futureapples000 has a brilliant futureapples000 has a brilliant futureapples000 has a brilliant futureapples000 has a brilliant futureapples000 has a brilliant futureapples000 has a brilliant futureapples000 has a brilliant futureapples000 has a brilliant future
Re: Back for more..VEXpro 2014 Product Unveiling

Quote:
Originally Posted by Aren_Hill View Post
The PTO Kit reuses many existing parts, including the main output shaft, this would typically be cut off where it meets the opposite plate. Rather than creating slightly tweaked versions of a bunch of existing parts we chose to repurpose existing things.

Also space is required for the gear/sprocket/pulley attached to the Versadog, Hence why this kit is listed as an option to only work with the WCD version of the 3 CIM DS.
Yup, my bad. I see what you mean about space for the plate sprockets. That being said, if you used a little sprocket that had the dog pattern in it, you could probably get away with this.
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


All times are GMT -5. The time now is 20:15.

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