@Clio Batali set the channel purpose: For discussing all bumper-related qualms and queries
I could find very little on bumpers with zippers, the best I found was that it SHOULD be possible.
Lots of people just use Velcro to strap flaps down. So we could do what we did last year but better and with Velcro instead of dual lock
Please remember to make "easily removable and re-attachable bumpers" a very high priority (if not the highest), because we won't be able to get the chassis through our school doorways with bumpers attached.
Here Robert is the link for the snap latches: https://www.mcmaster.com/#catalog/119/2924/=lk7v9y
We need 12 snap latches with 12 10-32 bolts. Also here is the original post.
James, your link to the snap latches at McMaster is not clear. Please specific model , Quantity , price , etc
make sure your order enough for 2 sets of nbumpers.
Will, are 10-32 bolts longer then an inch because we just need them to be connected securely on the chassis. Mr Chee, we have accounted for the 2 chassis and I will be more specific for Robert.
James, Please share with me those parts ? and Go to McMaster website and place in cart and then share cart with me. If you can't figure this out, ask Lucas R. how to do this.
K I'm on it. Due you want the links through slack or email
email please, Check my email I will forward you Lucas's example from Mcmaster. As always please include RObert so he can keep track of ouri nventory. Thanks
BTW, great idea on the latches !!! Good job on researching in CD.
Lucas. write an email to chee with the list of brackets and items
Give specific links not just a part name or number
So please finalize all bumper braket orders from AM.
Are the 10-32 bolts correct length ? I am assuming bolts go through slide-snap and bumper brackets ? or brackets and chassis ?
Will, see my email. I just forward the specs that James send me from Mcmaster request.
@james_sovick: according to the link you need m3 bolts
If that is correct you will need to order m3 bolts and nuts
Again where are these mounting screws for ? I am assuming bolts go through slide-snap and bumper brackets ? or brackets and chassis ? not clear. I don't see the link of slide snap in Mcmaster to M# bolts ?
To secure overlapping components, engage the slide and the mating stud until they snap together. That is from their catalog. The bolt would go through the mating stud then and you could secure it with a nut
Looks like M3 because of the point will brought up. The 10-32 came from the Chief Delphi post with latch design.
So if M3 , need lenght ? quantity, nuts ? Lets start from the beginning.
nuts ? Quantity , Mcmaster ? Please go back to Mcmaster and send me the order .
@whobbs1496 Thanks for catching the bolts as M3 and not 10-32, but it might have worked.
The best I can gather from the spec regarding the space we need on the frame or each latch would be: 1.75in (latch), 5/8in. (latch open), ~1in finger space to push latch closed. Question: How much bracket material do we need between the mounting hole and the edge of the bracket such that we don't weaken the bracket (e.g., how close to the edge of the bracket can we drill a mounting hole)? With the info we have, I'd estimate .5 in. on the non sliding end of the latch for bracket and installation clearance. So that gives us 3 7/8in.(say 4in.) needed per latch. James, what size did you use for your sample cardboard spacers?
I'm just posting as a reminder of things to do on Friday. I'm not expecting responses from anyone. On the chassis side, will mounting the pin into the outside chassis frame (i.e., framing member outside of the wheels) provide sufficient strength or will we need to span chassis framing members (inside and outside of the wheels)? Looking at the slideLatch.JPG picture (Unlatched side), our mounting plate for the pin (chassis frame), would be just slightly wider than the pin.
The cardboard was cut to roughly 1.75x11/16x.5 inches
Make sue your hardware does not extend outside the chassis frame perimeter. There is a certain limit equal to a bolt head that is allow . The specific dimension is in the rules.
It fits, the latches are going on top of the main frame.
Kenneth just put this on the Strategy group
The sewing machine I have is a bit old but is having some troubles. My mom will be trying to fix it. So as a back up does anyone have a sewing machine
We have a sewing machine if needed. Let me know if you'd like me to bring it to school.
I will bring it. I will be there between 2 and 3pm, unless you need it sooner (I can drop it off)
Will it work with only two brackets? As far as I can tell, the dimensions don't account for screw-heads securing the frame to the chassis.
All screen heads are on the outside of the frame
I'm talking about the connection between the wooden frame for the bumpers, and the bracket that has the slide bracket on it
We have 3 brackets on each bumper half. Six in total on the 2 half's of the bumper
Yes, but on the measurement from front to back, I don't think it accounts for the screwheads in between the bottom of the bracket and the chassis
It's OK the bolt heads are really small and will not add anything. I tried won't make a minor diffrence
What is the gap between the two pieces on the back?
@james_sovick: I recommend drawing a quick sketch and sending a photo of it
The back gap should be between 0 and .25 inch. There are a number of factors which contribute to the back gap, but it will mostly be determined by the layers of fabric over squishy noodles. The bracket and screw heads mentioned above can also influence it. We'd like the plywood of the two halves to come close (<.25inch), but not touch. The gap will be filled with squishy noodle beyond the ends of the plywood such that the two halves will touch. Here's a quick sketch, top view looking down at the back.
Just FYI; on Thursday I will be arriving about 20-30mins after the meeting starts.
Let's remember to weigh the bumpers on Sunday... just to make sure. Each section needs to be under 10 lbs. It is sufficient to weigh just one unless it is really close to 10 lbs., in which case, we should weigh the set to confirm each set is under 20 lbs. Also, if it is close, be sure to include the fabric and brackets.
Ok, here we go. For those not familiar with the problem we are trying to solve, I'll restate it. I has become clear that we can't mount our brackets on the top back of the chassis near the center as pictured up above with my fine sketch. So the plan I'm putting forward is to move the top brackets (with slide latch) to the top back corners of the chassis. The rest of this discussion will be focused on how to secure the two sections of bumper where they come together in the center of the back chassis. I'll provide a sketch as above and some pictures of a cardboard prototype (I couldn't care less about the Falcons and Patriots).
The slide latch brackets are moved out to the corner, a T bracket is only fastened to one bumper section. That bumper needs to be first off, last on. The T has a draw tight latch hook on end (yellow). It is inserted thru a new hole in the chassis wall. An L bracket is added to the inside of the chassis wall, the draw tight part of the latch is attached to that L bracket.
Analysis? GOOD: We have or can easily make brackets. The latch is a $5 part from Ace. Provides lots of support for the bumpers. Avoids the top of the chassis which will be in high demand. Is quickly and easily manipulated without needing to see what you are doing. Pulls bumpers tight to the frame. BAD/UNKNOWN: Is anyone else going to demand this space on the inside wall of the chassis? L bracket with hook cannot be attached to plywood, must be inserted after bumpers. Might get complicated and needs to be secured to the robot (chain, zip tie, etc.) so if it comes undone, it doesn't draw a penalty. Will latch open with contact with field elements/robots?
Another option for the latch is to use a pin with a big washer on the end and the same slide latch as elsewhere on the inside of the frame. GOOD: easier, smaller chassis hole. Consistent latch mechanism w/ the rest of bumper latches. Less parts. BAD: more difficult to reach latch, doesn't pull bumpers as tight to frame, need to order more slide latches.
An option that we should check out is to mount slide latches on the bottom of the chassis frame only for the latches at the center back. Since all other 3 latches are close to the chassis side, it might be possible to lift up on the bumper sides (to clear those latches) while rotating the center back down (to clear a bottom latch). This would be easiest to build, but might not work. Cart builders would need to know about this and we'd need to verify it can be easily manipulated while on the ground (i.e., is there enough room to rotate the center back down without the bumper hitting the floor?).
That's what I was just thinking; it should work
Recessing the mounting brackets is problematic. It will move the slide latch off the desired mounting location on the chassis. We should investigate only recessing the screw attachment part of the bracket and not the corner/top. Ie., bending the bracket on the side that attaches to the bumper.
To do list:
Were all clear to show up at 1:30 tomorrow. Lucas, Robert and James are clear to go
What do we have left to do on the Blues? Is it just the back brackets?
I mean, what do we have to do that doesn't require access to the robot?
Well maybe because we still need to look and see if everything fits
So that requires the robot but will mounting the BBs also require it.
No just the side because we still don't now if they fit on.
But yeah. For the most point we don't need the chassis
The bumpers are supposed to go on & off quickly. Consequently, even since we are not allocated chassis time, that doesn't mean we can't attempt fittings. A fitting test should be under 30 seconds. To me, it seems reasonable to assume we can find opportunities for this on Sunday.
A task that can be done without the chassis is to secure the fabric folds on the intake end of the bumpers. We don't want engagement/disengagement with other robots to pull out the folds.
Another task could be to add basic bumpers to the 2nd chassis. Something quick that keeps our team safe. Perhaps a U shape like the real ones but with back side only as long as the front. We can let the front and back hang (no attachment) and the side will be attached with two bumper chassis kit brackets (we have 4 brackets). I think it would be good to have experience with these brackets that are custom made for the robot chassis kit that we've used this year. That experience will benefit us next year with regard to what it would take to secure the kit brackets for competition. These brackets are quick on/off so the bumpers can be removed faster than the real ones. Just an idea... I'm might be paranoid, but I think if the robot can drive, we'll drive it, and it should be safe. We can have creative fun with the fabric. I've seen a girl's competition swim suit in the lab. That would make for some wild bumpers if it can be used. Does it belong to @adriannacarter or @rosebandrowski?
Another point of view in support of the second robot having bumpers: As autonomous code is tested, we need to align the chassis against walls, etc. If we make modifications with a bumperless test robot, we may be off by a few inches when we use the actual robot in competition. So bumpers (at least of similar dimension) would be a great benefit to the programming team. (And may help keep them a bit safer...)
Would it be possible to put some latches on the backup? We would only need two or three per side because it wouldn't be in a competition.
We would need some way of taking bumpers off the backup, as it still needs to fit through doorways...
We would just have to talk with Chee to see if we could use the pool noodles and latches
Also would it be a good idea to make back up brackets?
Yes on backup brackets for competition . Temp. bumpers for second robot is good idea for programmers . Maybe take Aries bumpers and modify . This needs to be done ASAP for programmers if you decide to do it . You can angle the robot with bumpers to fit through door . I guess you guys should up sat if possible .
I've made other plans for today (Sat.) since bumpers on the 2nd chassis have been consistently rejected even though I believe that IF it can drive, we will be driving it. I believe it should have bumpers for safety. Friday it was driving in autonomous right behind people paying attention to the other robot. I watched as it clipped the corner of the building a couple of times. That's my morning rant... moving on.... My suggestion for backup chassis bumpers is as I said above. I believe that will be fastest. Use the bumper kit brackets, only attach to the side of the chassis, no chassis down time, no latches(!). In the tray of bumper parts on the sponsor wall shelf, I put a bumper bracket with a quick wire lock. This method will be good enough for non-competition. The only difficult part will be that the bracket mounting locations will need to line-up with the existing holes on the top of the chassis. Also the brackets need to match up to the chassis at a location where there are no bolts/axles protruding out the side. I can build these on Sunday AM. Let me know if that is desired and I'll come in early with programmers.
Wood: 28.5"x5.5" x2, 6"x5.5" x4; Corner brackets: use pkg from Ace in tray, they'll be mounted sufficiently above and below the chassis so the rounded inside corner will not be in the way. Noodles: Use the junkiest ones we have. Fabric: Ask the hopper folks if they're done with that blue stuff they're using. Duct take noodles, don't waist time heating/gluing. Don't miter noodles, just run one side of corner long.
Captians say no because it's not worth it.also due to time and need for other things. No need to come in at 9:00.
Anything happening with bumpers today (fitting blue, adjusting red)?
You will have a few minutes at the start of the meeting to take off the red bumpers so you can match the blue bumpers to the red
But the brackets on the blue bumpers do not line up with your mounting points on the robot
We do have to open up the hole for one of the rear bottom brackets a bit more.
On Friday, red looked close to ground on the front port corner. Is anyone concerned?
Whoever is driving robot today, it would be nice if they can try and drive over a yellow gear. Bumpers are low to prevent that but if it isn't prevented because of the squishiness of the noodles, we might consider raising them to reduce risk of disqualification (?) due to bumpers touching ground.
Calendar say mtg starts at 1. Is that still the case or was it moved up?
Looks like the red bumper that's sagging is just fabric
@jeff_dalton: The regular meeting still starts at 1, but many mechanics (including bumpers) are meeting earlier at 9am to get a head start
Also, good point about the gear. We'll be sure to test that today with the programmers
Due to car trouble I am going to be 5 mins late
Here's what I know needs to be completed: (1) two brackets put on a blue bumper, (2) hole filed bigger as marked on bottom of chassis, (3) sew (?) intake folds down. Anything else?
@jeff_dalton @Clio Batali drove over the gears - everything looked fine, nothing exciting to report — other than our teleop code not working initially… 😕
(She means "attempted to drive over the gears, but was unsuccessful in doing so")
@jeff_dalton we are planning on building a full set of backup brackets, should we get them tomorrow?
Sure. If Robert (QM) directs me to pick them up, I'll get 8 (or whatever Robert wants) from ProBuild. If someone else wants to do it, let me know and point them to the location. What time are people showing up? Calendar says 1PM.
One of your brackets on the left blue bumper is not aligned properly. Please fix it tommorow
We will see what other teams did. Idk if those are legal and if there just test bumbers
team, thank you for not embarrassing us with our bumper 🙂 I am loving what you guys have built this year!! Much appreciation!!
Can you guys come back real quick? @Harper Nalley @james_sovick
So, because of the fabric, we need to put those corner brackets on the inside of the wood. Do we want to countersink the screw holes?
That is, if we put those extra corner brackets on
Can someone please summarize the issue with bumpers?
Those backup corner brackets, if we need to use them, we'll need to countersink the holes because they would have to go on the robot side right?
I seem to remember having the opinion that they needed to go on the inside, but I can't remember why. Would the existing corner brackets get in the way of mounting these? If so, then they'd need to be removed. The fabric would need to be moved back past the corner. What other considerations are there? What is the problem that this would address? Is it that the screw heads are two tight against the frame on the existing corner brackets?
We got another rip in the red bumpers. Currently it's taped with gaffer's tape. Please keep that in mind, and sew up at some point
Robert and I thought more about what if the corner brackets broke, so we widened some holes in the backup outside corners and found some inside brackets.
And we thought about what we could do for the corners next year.
And finally we taped some bits of the fabric to prevent fraying.
Anything new to report with the bumpers?
Okay. My mother has a spare sewing kit that I can bring and leave in engineering.
I think after Cheney we will see if we should use some heavier thread for repairs
I think tomorrow (09/4) we (bumper team) should stitch up the fabric, and drill in some new holes.
To anyone at worlds: How are the bumpers holding up?
Fine as in good fine? Or fine as in overall good, but there are a few new problems?
So, James and Robert. Next weekend I am going to cut out the wood for the bumpers. Based on my research, the 5" height and 3/4" thickness we used last year are the standard. And then cutting the wood to 55" should give us more than enough wiggle room.
Just in case the 2018 game IS a water game, we should think about finding new thing to replace the wood backing. I will still cut out the wood if they were joking about buoyancy.
I did some preliminary research, and we could use something similar to what 5803 and I think what 2471 uses. It's a honey comb aluminium piece.
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I just got the bumpers cut, so we can start drilling tomorrow.
@Nora @Harrison Gilmore Bumpers should be done by Saturday February 10th. We should be getting a fourth person so we will be able to work on both sets (the red set and the blue set) at the same time interval.
@Kenneth Wiersema These are the CAD files for the bumpers, they don't have brackets or anything, it's just the wood and the fabric.
@Nora @Harrison Gilmore Remember to spend some time tonight and/or tomorrow learning how to sew on a sewing machine.
What model sewing machine do we have, out of curiosity? The one I have is a tad archaic, and may not be suitable for practice.
Well, mine is in many pieces, so I don’t know.
@Nora @Harrison Gilmore @Jules Blythe there is a meeting tomorrow, (Monday, February 5th) are any of you able to go?
I have violin practice at 2:00, I could come possibly come at 3:00.
Additionally, if I play my cards right I could stay afterwards.
@Harper Nalley how far did you guys get with the sewing?
@Nora @Jules Blythe @Harrison Gilmore Today we will be working on putting brackets on the robot. This will entail putting locktight on the M3 screws cutting them down (M3 screws are the ones that attach the latches to the brackets). We will be drilling some holes in the robot where the brackets will be, and attaching the latch hard-points to the bot.
Please update me at the end of the meeting as to if we are finished/what we accomplished.
We are almost done, we need to put a couple more brackets on and two more hard-points into the robot. I have worked it out with Peter and we won’t be getting in the way of him working on electronics.
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This is the instruction manual for bumpers
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@CruzStrom please get back to me on Wed. about the bumper brackets that Lucas requested . Do we have some lying around the metal scrap tray ? Have we removed from old bumpers ? If we need to order ? How many and from where ? @Harper Nalley @MicahGlasby @Kenneth Wiersema Lucas said he could not find on Amazon and he personally purchased them last year from what used to be called Probuild. This should have been ordered during preseason if needed .
@coachchee Micah has the numbers for the orders. The reason we need more stuff is because of unforeseen changes to the design that this game and robot require.
Those aren’t correct, the ones we need for the sides are longer on one end
I know that they are 3” wide and 1/16” thick. However, the ones we need the most of are 4” wide and 1/8” thick
If the pricing on that bracket Mr. Chee posted from Amazon is any indication, it would be a LOT cheaper to buy at ProBuild—probably around 1/5th the cost.
Hi all, I assume you already have a plan for bumpers, but in case you're interested here is a good thread on bumpers from Chief Delphi (including a how-to paper): https://www.chiefdelphi.com/t/paper-frc-robot-bumpers-guide/163091
@chrisrin I considered doing that last year, but it would have required that we paint on the numbers which, while possible, wouldn’t be very time effective. It’s up to @Micah_Glasby, but I’d say we should use our current number system this year and use up the numbers we have, and then try this next year rather than buying new numbers.
*Thread Reply:* Are you aware of @chrisrin's offer to get the material cut into that shape using a fabric "CNC"? He posted something about it here: https://spartronics.slack.com/archives/C16U2PW1K/p1547875865259800 @Micah_Glasby seemed to be on board.
*Thread Reply:* What I might do is ask her to make a few sets of numbers, and then you could use them or not.
*Thread Reply:* I know it’s not very time effective, but I’m a fairly good painter and would be more than happy to do the numbers if needed. I could probably get it done in 1-2 meetings; especially if given stencils.
*Thread Reply:* @chrisrin That would be awesome! Do you need us to get a sheet of the material for her?
*Thread Reply:* It would be a good idea to specify the preferred material at least. Are the letters iron-on fabric, vinyl, or what? If vinyl, you can actually just upload your own font and have them made online. Here's one place I found: https://www.youcustomizeit.com/p/Design-Your-Own-Graphic-Iron-On-Transfer-Up-to-6-x6-Personalized/186786?msclkid=e529af9948f613e94299f3dea30ae982&utm_source=bing&utm_medium=cpc&utm_campaign=YouCustomizeIt%20PLAs&utm_term=4576785872183964&utm_content=All%20Products#designer
*Thread Reply:* Come to think of it, I would bet Sound Reprographics could set us up as well. Happy to ask my mom though - she likes helping with things like that - a chance to use her machine.
*Thread Reply:* I'll see what the numbers we have are made of, but my guess is we'll end up getting vinyl.
*Thread Reply:* @Micah_Glasby My mom replied and said she would enjoy contributing the bumper numbers in the team font. We need to confirm for her what material. She works at a fabric shop & they have fabric or vinyl, adhesive or iron on. Also, when would they be needed?
@Cruz_Strom do you know if we received FIRST Logos in the tote this year?
*Thread Reply:* @Harper Nalley, I will check during the meeting.
Concerning bumper numbers in our team font, my mother is interested in making them. Here are the open questions:
*Thread Reply:* @Micah_Glasby Update on the numbers from my mom. She's going to work on them this weekend. She'll use iron-on vinyl from the fabric store where she works. And based on the measurements we took of the existing numbers, here is what the numbers will look like. If it is too late for this year, we'll have them for future years.
I’m going to try to bring my sewing machine for the bumpers next meeting, but I haven’t sewn for a little while so I would like some help or if someone’s may be willing to sew our bumpers who has more experience (@Kate_Swietlik or @riyadth) then by all means, sew away! P.s. do we already have supplies for the sewing in the bumpers drawer or will we have to get some?
*Thread Reply:* I don't have bumper experience with sewing (I just loaned my machine the last couple of years). But I do know how to thread a needle and do some basic stitch work, so I might be able to point someone in the right direction. I recommend searching for "sewing frc bumpers" on YouTube for some good instructional videos.
*Thread Reply:* There might be some tips on bumper sewing in the “how to” presentation posted on Jan 22. You can also search Chief Delphi in addition to YouTube.
Quick q: what all did we get done yesterday?
@Lane_Johnson will know more than I do, but he started putting the numbers on the fabric.
Interesting discussion about solid vs. hollow pool noodles... https://www.chiefdelphi.com/t/hollow-vs-solid-noodles/166972
Apparently if defense will be a factor, solid are better. I was actually looking because I'm interested in how much bumpers compress when they impact a wall at full speed. Consensus is that solid noodle bumpers will compress less (which is better in the context of the problem I'm looking at - see the hatch channel if interested). Is it safe to assume we're using hollow pool noodles, given they're more common?
@chrisrin In the past we have used solid, I’m not sure about this year though, @Micah_Glasby should know.
Hollow generally. We ran out so there is one side segment and 1 or 2 front or back segments of solid. After hitting them all I didn’t notice much of a difference. However, I don’t know how they will behave in the future.
Knowing what we know now, these 2 5/8 solid ones (should pass the approximately 2 1/2" thickness rule) would be good to use on that side at least. https://www.amazon.com/gp/product/B07GZZ8GTL/ref=ox_sc_act_title_1?smid=A2HW502SC5OSR8&psc=1 Not sure if it's worth considering changing that side, but we are in a bit of a pickle with the chute being exposed to over a ton of force, and it could help a bit.
@Harper Nalley What do bumpers need for open house? I gathered from Andrew that in the past we have shown the progression in bumpers. Is that correct? If so, should I pull down all the bumpers from past years?