Originally Posted by Paul Copioli (Post 1311086)

Profile Shift, or addendum modification, can be positive or negative. For a positive profile shift, the tooth looks longer and pointier. For a negative profile shift, the tooth looks short and stubby.

The primary use for profile shift in industry is to avoid undercut in small gears. If you want to see severe undercut then look at the 12 tooth CIM pinion. Undercut lowers the gear's max load carrying ability and is necessary so the mating gear's tooth tip does not interfere with the root of the smaller gear.

As a rule, every gear we design will have profile shift to avoid undercut except when the market conditions do not allow it. For example, the 14.5 pressure angle, 20 Diametral Pitch gears that have been used as a standard in FRC have always used 0 profile shift. Making a 12T pinion with 0 profile shift now would mean all of the center distances would be too close together.

This is very important for really small gears with small module (1 or .5). All of our VEX motors used in VRC have significant profile shift to increase the load carrying capability.

All of the Versaplanetary gears have addendum modification to minimize the
planetary backlash and increase the strength as much as possible.


You really are shifting the profile either out (+) or in (-). QTC gears has really great introductory information on their web site about gears. I make all my new engineers read that web site before I give them the more advanced information.

By the way, the 11T pinion is actually stronger in every way than the 12T gear due to the 12T gear's severe undercut. However, the 12T gear's strength is plenty sufficient for use with a CIM motor.

Paul

Originally Posted by geomapguy (Post 1311003)

Are the versa planetary base models 1:1 ratios??

Originally Posted by Clinton Bolinger (Post 1311059)

If teams would like to compare shipping options between VEX (Greenville, TX) and The Robot Space (Lapeer, MI) feel free to check out http://ship.therobotspace.com

Originally Posted by Paul Copioli (Post 1311086)

The primary use for profile shift in industry is to avoid undercut in small gears. If you want to see severe undercut then look at the 12 tooth CIM pinion. Undercut lowers the gear's max load carrying ability and is necessary so the mating gear's tooth tip does not interfere with the root of the smaller gear.

Originally Posted by jb1403 (Post 1311098)

Also has the bearing blocks / chain tensioning device for the versa frame been placed on the website? I have not be able to locate them.

Originally Posted by jb1403 (Post 1311098)

Will the standard 2 cim ball shifter be given the optional lower and 3rd stages seen on the 3 cim version? Also has the bearing blocks / chain tensioning device for the versa frame been placed on the website? I have not be able to locate them.

Originally Posted by Ronnie314 (Post 1311104)

Does anyone know if the 4 "center" wheels will have a 1/8" inch drop in a 8 wheel drive configuration??

Originally Posted by AlecS (Post 1311105)

Yes, each Versa-Block has a 1/16" offset built into it, which is consistent with the notch on the top of the block. By orienting the blocks, you can achieve a 1/8" drop in a 6wd, 8wd, or 10wd.

In a typical 8wd, you would position the 4 outer wheels with the notch down, and 4 inner wheels with the notch raised.

Originally Posted by Ronnie314 (Post 1311107)

Are there pre-drilled holes in the outer walls for the different drive train configurations like 6 wheel, 8 wheel, etc?

Originally Posted by AlecS (Post 1311110)

No, the VersaFrame 2"x1" tubing does not have pre-drilled holes in the sides, there were simply too many possible drivetrain configurations to account for all of them with one pre-drilled tube.

The assembly instructions, coming soon, will detail the specifics of creating the holes in the tube for wheels. The general idea though, is that the hole can be very rough, all it needs to do is provide clearance for the shaft.

At WCP we used a 1.25" hole-saw to make all of the holes, using a drill-press.

Originally Posted by Ronnie314 (Post 1311111)

So all the stress is being put on those blocks which are attached to the 1x2 correct?

Originally Posted by geomapguy (Post 1311108)

Are the versa planetary base models 1:1 ratios??

The $29.99 option
http://www.vexrobotics.com/vexpro/ge...planetary.html

Originally Posted by AlecS (Post 1311114)

Correct, the bearings are held entirely in the Versa-Block, so the wheel load is distributed evenly all along the top and bottom of the tube where it is clamped. The Versa-Block is by design, extremely robust, and the bearings are held .25" out from the tube, putting even less stress on the shaft/bearings then if the bearings were held inside the tube.

Originally Posted by Ronnie314 (Post 1311116)

Idk if its just me but in the picture on the WCP website, the 3 cim shifter has a internal shaft but the 2 cim shifter is shown with the external shaft. How will this work with the alignment of the sprokets??

Originally Posted by AlecS (Post 1311118)

What's actually going on is there are two different types to each WCP transmission. Standard, which the 2 CIM Shifter is shown as, is shorter and doesn't have sprockets or a bearing. Then there is the WCD, which is longer, and includes two sprockets and the bearing block. The overall shaft length for both is the same.

The image for the 2 CIM Shifter is currently a Standard, and the 3 CIM shows the WCD+PTO model, but both transmissions are available in either configuration. We are working on getting images of all different configurations up on our website.

Hopefully this is what you were refering too?

Originally Posted by Andrew Lawrence (Post 1311120)

Alec, if I ordered the WCP 3 CIM DOG Shifter, would it still have the plates of the PTO transmission, or would it be the plates of the 3 CIM SS just with a shifting shaft in there as well?

Originally Posted by Paul Copioli (Post 1311121)

The plates for the WCP PTO transmission are the same plates as the WCP 3 CIM shifters. When you purchase a WCP 3 CIM Shifter, you get the plates necessary to do a PTO. Please note that only the WCD version of the 3 CIM shifter supports the PTO option.

Originally Posted by s_forbes (Post 1311004)

11 tooth pinion with the same pitch circle diameter as a 12 tooth pinion? Sounds like dark magic to me.

Originally Posted by Ronnie314 (Post 1311166)

Does anyone know how they plan on mounting the transmissions to the versa chassis? Is it something they will have a mounting plate for or will we be responsible for however we want to mount them?

Originally Posted by Sparky3D (Post 1311191)

I'm hoping that Vex/WCP will elaborate on this as well. After looking at the pictures and release video, it looks like they drilled holes in the sides of the frame rails and face mounted them, but I'm hoping there's more to it than that. Trying to get the mounting holes properly aligned with just "a saw and a drill" would be rather difficult. :confused:

Originally Posted by Ronnie314 (Post 1311166)

Does anyone know how they plan on mounting the transmissions to the versa chassis? Is it something they will have a mounting plate for or will we be responsible for however we want to mount them?

Originally Posted by Ronnie314 (Post 1311166)

Does anyone know how they plan on mounting the transmissions to the versa chassis? Is it something they will have a mounting plate for or will we be responsible for however we want to mount them?

Originally Posted by btslaser (Post 1311201)

It appears that they attach to the VersaBlock which is clamped securely over the tubing. The only hole you would have to drill is the clearance hole for the hex shaft. You could use a step drill to bore an oversized hole to allow for chain/belt tensioning on the end blocks.

Originally Posted by Ronnie314 (Post 1311204)

They are planning to put the entire shifter on the versa block...? That doesn't seem like the best idea, not saying they are not strong enough but doesn't seem like a rock solid idea to me. Please share ideas on this.

Originally Posted by Answer42 (Post 1311130)

A COTS 3 pound PTO gearbox. FRC certainly has come a long way.It used to be only the top 1% of teams could pull something like that off.

In summary, if a VENDOR sells a system or a kit, a team must use the entire system/kit Fair Market Value and not the value of its COMPONENT pieces. Example1: VENDOR A sells a gearbox that can be used with a number of different gear sets, and can mate with two different motors they sell. A team purchases the gearbox, a gear set, and a motor (which are not offered together as an assembly or kit), then assembles them together. Each part is treated separately for the purpose of BOM costing, since the purchased pieces can each be used in various configurations. Example2: VENDOR B sells a robotic arm assembly that the team wants to use. However, it costs $700, so they cannot use it. The Vendor sells the “hand”, “wrist” and “arm” as separate assemblies, for $200 each. A team wishes to purchase the three components separately, then reassemble them. This would not be legal, as they are really buying and using the entire assembly, which has a Fair Market Value of $700

Originally Posted by AdamHeard (Post 1311218)

I can't seem to find a CAD file for the versablocks on either site, has anyone found this?

Originally Posted by Alpha Beta (Post 1311211)

We do not know the rules for 2014, so I'll ask this question in reference to last year. Would the PTO gear box from WCP have been legal in 2013? The gear box without pneumatic cylinders is around $350. With both cylinders it's $430-ish. You can purchase the gear box without them, but it won't function. Of course the same is true for motors and pinions. If you purchased the full assembly with pneumatics, motors and pinions for just over $525 would it have been legal?





PS. If FIRST had a goal of more teams doing their own design work they could lower the $400 limit. If they wanted to lessen the amount of design work they could raise it instead.

Originally Posted by Ben Martin (Post 1311209)

Thank you everyone at Vex Robotics/IFI for introducing all of these new products

Originally Posted by Akash Rastogi (Post 1311231)

And West Coast Products :)

Originally Posted by Alpha Beta (Post 1311211)

We do not know the rules for 2014, so I'll ask this question in reference to last year. Would the PTO gear box from WCP have been legal in 2013? The gear box without pneumatic cylinders is around $350. With both cylinders it's $430-ish. You can purchase the gear box without them, but it won't function. Of course the same is true for motors and pinions. If you purchased the full assembly with pneumatics, motors and pinions for just over $525 would it have been legal?





PS. If FIRST had a goal of more teams doing their own design work they could lower the $400 limit. If they wanted to lessen the amount of design work they could raise it instead.

Originally Posted by sdcantrell56 (Post 1311207)

Could you guys provide some of the information pertaining to HTD versus GT2 specifically in ratcheting performance? I tried finding data to back up the claim of HTD being better for rapid direction changes and can't find anything to substantiate this.

Originally Posted by sdcantrell56 (Post 1311207)

Could you guys provide some of the information pertaining to HTD versus GT2 specifically in ratcheting performance? I tried finding data to back up the claim of HTD being better for rapid direction changes and can't find anything to substantiate this.

Originally Posted by Alpha Beta (Post 1311211)

We do not know the rules for 2014, so I'll ask this question in reference to last year. Would the PTO gear box from WCP have been legal in 2013? The gear box without pneumatic cylinders is around $350. With both cylinders it's $430-ish. You can purchase the gear box without them, but it won't function. Of course the same is true for motors and pinions. If you purchased the full assembly with pneumatics, motors and pinions for just over $525 would it have been legal?





PS. If FIRST had a goal of more teams doing their own design work they could lower the $400 limit. If they wanted to lessen the amount of design work they could raise it instead.

Originally Posted by Akash Rastogi (Post 1311250)

I thought the tiny new hex broached VersaWheel was pretty cool. What led you guys to making it 3.25" in diameter? I'm glad it is available!

Originally Posted by Andrew Lawrence (Post 1311242)

While I don't have numbers to back this up, 256 made a belt drive in the offseason and tried out both HTD and GT2 belts and pulleys, and while the GT2 ratcheted when we went full forward to full reverse, the HTD stayed strong and kept its hold on the drive. I would definitely go with HTD again.

Originally Posted by tim-tim (Post 1311262)

So they can continue to make their drive modules lighter and more compact?

Originally Posted by Jared341 (Post 1311275)

In reality, a wise designer would probably want to have enough of a safety margin that either profile would not ratchet.

Originally Posted by Chris is me (Post 1311271)

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.

Originally Posted by Andrew Lawrence (Post 1311291)

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.

Originally Posted by Chris is me (Post 1311294)

Did you adjust tension between belt changes?

What width were the belts?

Did you use different pulleys or the same type? Which kind?

Originally Posted by Andrew Lawrence (Post 1311297)

All pulleys were the same aluminum 24 tooth cut from the same stock, all the same width.

Originally Posted by Chris is me (Post 1311298)

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.

Originally Posted by Andrew Lawrence (Post 1311297)

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.

Originally Posted by JVN (Post 1311239)

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

Originally Posted by apples000 (Post 1311317)

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.

Originally Posted by apples000 (Post 1311317)

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.

Originally Posted by apples000 (Post 1311332)

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.

Originally Posted by apples000 (Post 1311317)

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.

Originally Posted by Aren_Hill (Post 1311334)

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.

Originally Posted by apples000 (Post 1311336)

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.

Originally Posted by AdamHeard (Post 1311340)

That limits the versatility of it.

When selling a COTS part you have a different set of goals than a team.

It's not surprising that someone could make a 3 CIM w/ PTO gearbox smaller and lighter than vex, but it will likely only fit a few situations. Vex/WCP must sell a gearbox that will work for as many as possible. I feel they've done a great job o this.

Originally Posted by Boe (Post 1311370)

So i was looking at the new wcp 3 cim (not the ball shifter) I saw that the two lower cims both drive one gear and then the third (top) cim drives the same gear but with a gear between, wouldnt this mean that the top cim is contributing less/more then the other two?

Originally Posted by cadandcookies (Post 1311376)

Will CAD models be released for the traction wheel traction tires? I know my team is looking at those as an alternative to tread.

Originally Posted by AlecS (Post 1311380)

Fixed, the CAD is now available here.

Originally Posted by Oblarg (Post 1311481)

The VersaWheel page doesn't list a weight for either of the wheels; anyone know what the weight is?

Originally Posted by z_beeblebrox (Post 1311508)

I' getting a 404 clicking the link in your post.

Originally Posted by BBray_T1296 (Post 1311518)

Just a question specifically about the WCD gearbox with PTO offered a VexPro, from someone who has never used a PTO before.

What if you want to operate the PTO without running the wheels? I would think you would want to run the PTO while not moving in many more situations than you would want to while rolling.
Studying the CAD, I am fairly certain this is not possible.

Originally Posted by smistthegreat (Post 1311521)

I'm not sure if this was intended with the design, but you should be able to find a 3-position cylinder to put on the bottom dog, letting you shift the drivetrain into a neutral gear (with the dog disengaged, between the two dog gears) when you want to engage the PTO.

Originally Posted by JVN (Post 1311239)

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

Originally Posted by Jared341 (Post 1311275)

Given that HTD is at this point a de-facto standard while GT2 is a proprietary profile*, I don't think a lot of belt manufacturers would want to go on the record with an unbiased recommendation. Gates is going to say that GT2 is the way to go, while everyone else will say HTD.

In reality, a wise designer would probably want to have enough of a safety margin that either profile would not ratchet.

* A brief Google search couldn't confirm or deny this, but it is my recollection. I'm sure that CD will correct my statement if it is incorrect :)

Originally Posted by smistthegreat (Post 1311521)

I'm not sure if this was intended with the design, but you should be able to find a 3-position cylinder to put on the bottom dog, letting you shift the drivetrain into a neutral gear (with the dog disengaged, between the two dog gears) when you want to engage the PTO.

Originally Posted by BBray_T1296 (Post 1311526)

Oh yeah! I just remembered another thread wondering if there was a neutral for the ballshifter, and there was a link to the piston Im sure you are talking about. Thanks

Originally Posted by s_forbes (Post 1311557)

Some clarification if possible:

The difference between gears with versakey option and those without - does this refer to just the female versakey pattern in each gear? Do the non-versakey gears still come with the bolt pattern?

Also, I see two availability options: "In stock" and "Ships before kickoff". How long would it take each of these to ship if I ordered today?

Originally Posted by Travis Schuh (Post 1311601)

Everything I have seen in the Gates literature showes the GT2 profile ahead of HTD. Check out page 10 of the Gates Light Power and Precision manual. This shows the ratcheting torque of 5mm GT2 and HTD being evenly matched across a range of tensions tested at 2300 RPM (roughly 3X FRC drive train speeds), with GT2 being slightly better than HTD (<5% and decreases as tension increases).

Originally Posted by DevenStonow (Post 1311884)

Here's something neat that I'd love to see from VEX: JVN's mechanical calculator as some sort of web app.

Originally Posted by Akash Rastogi (Post 1311888)

And for the sake of convenience: A belt C-C calculator to help select which VEXPro stocked belts and pulleys to buy, right on the VEXPro website. Not hard to find elsewhere, but it'd be great for people who are new to designing for belts.

Originally Posted by DampRobot (Post 1311891)

Seconded. This would be really, really helpful.

Originally Posted by AlecS (Post 1311931)

Center distance calc now available here and will be on VEXpro's site soon.

Works for any size pulley, and gives out the two nearest VEXpro belt sizes, to the desired center distance. The pulley size also turns bold when you are using a VEXpro pulley. Any box that is white can be edited by the user, boxes that are gray are info from the calculator.

Originally Posted by Nemo (Post 1313086)

I've been playing around with VersaPlanetary CAD models today, and it has been a learning experience. They're really neat little boxes.

What holds a ring gear add-on stage to the new dual input gearbox? The STEP model shows a couple of 10-32 screws sticking out, but there is no threaded 10-32 hole to go into on the ring gear stage. The 10-32 screw would seem to go into the the cutout corners of the ring gear block. Does the ring gear's shoulder press fit into the plastic housing of the dual input?

This picture shows the 10-32 screws sticking out and not connecting to the ring gear. What have I missed?

Originally Posted by Aren_Hill (Post 1313090)

Hey Dan,

The casing has a pin in it as well, to lock the ring gear stage from rotating.
This coupled with the 10-32's screwing into the output stage, and the ring piloting, hold the gearbox solidly together.

-Aren

Originally Posted by ttldomination (Post 1313412)

I notice that the Traction Wheels are now available with tread.

Can you guys provide us some details about this tread (COF, etc.). I would also be interested to know why the tread was pulled last year and how this new tread fixes those issues...?

- SUnny G.