Quick release bumper design

[Bob Steele]

Originally Posted by Alan Anderson

I assume I'm misunderstanding this. It sounds like you're riveting your bumpers to your robot...and that can't be right. Among other things, it would take forever to remove them for inspection. Please help me understand what you're describing.

Our fastening system utilizes rivets top and bottom.
They are quicker to get on and off than bolts and nuts actually. Our whole robot is riveted in constuction... similar to the 217/148 style of construction...

The school we come from is Aviation High School ...right in the middle of the land of Boeing.
Rivets come natural to us...

Many of our students want to go on into aero engineering...

thanks!!

[Bob Steele]

Originally Posted by GaryVoshol

The 8-inch support rule says that you cannot have any missing sections of frame greater than 8". It doesn't say your bumper has to be connected every 8".

Most teams using traditional bolts and wingnuts use 2 or 3 connectors per side.

I wasn't referring to the number of attachments but to the ability to keep all of those points tight against the frame sections...

i am sure they can do it... I just want to make sure that the entire rule is considered..
Quick release mechanisms, from my experience, are not commonly as tight as standard solutions...

thanks!!

B

[Vikesrock]

Originally Posted by Bob Steele

I wasn't referring to the number of attachments but to the ability to keep all of those points tight against the frame sections...

"Tight" has a bit more flexibility to it this year. 1/4" of space or less of space officially counts as supported.

[bmxer51]

Okay we finally finished making all the brackets (16 because we are making two complete sets)

I, the build team captain, put another student in charge of making the brackets. However, not a single one fit so I re did them and if they are done right everyone of them fits the first time. When I get some time i will make a how-to video.

Both sets will be completed by this wednesday I will keep you updated

[RRLedford]

I am concerned how quick release designs are not a violation of rules.

The hardware attached to the plywood can only protrude out from the plywood surface a bit more than 1/4" if it stays attached to the bumper.

So if you then declare the fancy bumper hardware is, instead, part of your robot and not part of the bumper, then they are sticking out past the outer planes the frame, which is also a violation, plus it reduces the max size of your frame.

So this seems to be a Catch-22 scenario. How is the quick release attachment H/W going to BRIDGE across both the frame and the plywood enough to strongly join them when the joining h/w can only overlap onto the frame by ~1/4"? Having only 1/4" of metal protruding from the plywood that can overlap onto the frame is not very much to work with for accomplishing an effective quick release design. Am I missing something here?

BTW, even if horizontal bolts going through the frame to protrude enough to screw into flush threaded inserts, set into the plywood, are used to secure the bumpers, are the bolts considered part of the robot or the bumper? If they are part of bumper, they are a violation, and if they are part of robot they can also be considered a violation (no protrusions from robot frame can go out very much), plus they would be extending the size of robot.

-Dick Ledford

[Vikesrock]

Originally Posted by RRLedford

The hardware attached to the plywood can only protrude out from the plywood surface a bit more than 1/4" if it stays attached to the bumper.

......

Am I missing something here?

-Dick Ledford

I cannot find justification for this statement in this year's competition manual. I am assuming that this interpretation came from <R07-L>, but that rule only governs how far the hard parts of the bumper may extend outside the frame perimeter and does not restrict extension of the bumper inside the frame perimeter.

[GaryVoshol]

Originally Posted by RRLedford

I am concerned how quick release designs are not a violation of rules.

The hardware attached to the plywood can only protrude out from the plywood surface a bit more than 1/4" if it stays attached to the bumper.

So if you then declare the fancy bumper hardware is, instead, part of your robot and not part of the bumper, then they are sticking out past the outer planes the frame, which is also a violation, plus it reduces the max size of your frame.

So this seems to be a Catch-22 scenario. How is the quick release attachment H/W going to BRIDGE across both the frame and the plywood enough to strongly join them when the joining h/w can only overlap onto the frame by ~1/4"? Having only 1/4" of metal protruding from the plywood that can overlap onto the frame is not very much to work with for accomplishing an effective quick release design. Am I missing something here?

-Dick Ledford

I don't know if you're missing something, or if I am. Where did you get a 1/4" fastener rule?

Perhaps you're misinterpreting <R07-L>:

L. “Hard” parts of the BUMPER (i.e. plywood backing, fastening system, and clamping angles) may extend up to a maximum of 1” beyond the FRAME PERIMETER. “Soft” parts of the BUMPERS (i.e. pool noodles and cloth covering) may extend up to 3½” beyond the FRAME PERIMETER.

The "hard parts" can only extend up to 1" outside the frame. There is no restriction on how far inside the frame they can extend.

[jasonpatel555]

We did something very similar in 2010. I don't have any close up videos of the mechanism itself, but it was almost exactly the same, and we didn't have any problems with holding strength, and we had more then a few very hard hits. As for the "bumper support rule" (<R07> K), it was our understanding during inspection that because the bumper was in contact with the frame that when the bumper was hit it transferred the load directly to the frame, (ie it wasn't hanging off the side causing the bumper to bend) and therefore was supported. However our robot was quite small last year and our mounts were never more then 8" apart anyway. Have a look at the diagram in the section 4 <R07>-K, the right most scenario should answer your question.

This was our change out time
http://www.youtube.com/watch?v=PQRya...layer_embedded

and this was how we made them
http://www.youtube.com/watch?v=PcZjm19kcsg&NR=1

http://www.youtube.com/watch?v=BaHGN...eature=related

[RRLedford]

Originally Posted by GaryVoshol

I don't know if you're missing something, or if I am. Where did you get a 1/4" fastener rule?

Perhaps you're misinterpreting <R07-L>:

The "hard parts" can only extend up to 1" outside the frame. There is no restriction on how far inside the frame they can extend.

Yes, but if the ~3/4" plywood is included as part of this 1" limit, then only ~1/4" remains available for metal "hard parts to interface with the frame.

My question remains unanswered. Are the quick connect "hard parts considered part of the BUMPERS or part of the ROBOT? If they are extending more than ~1/4" from the inner face of the plywood toward the frame, then it is a violation. If quick the quick connect hardware is considered part of the robot, then they are alos limited as to how far out from the frame face they can project into the plywood.

It still seems like a Catch-22 situation. Does anyone get what I am asking?

-Dick Ledford

[RRLedford]

Originally Posted by Vikesrock

I cannot find justification for this statement in this year's competition manual. I am assuming that this interpretation came from <R07-L>, but that rule only governs how far the hard parts of the bumper may extend outside the frame perimeter and does not restrict extension of the bumper inside the frame perimeter.

I interpret R07-L to mean that the SUM of the plywood's thickness AND any metal attached to the plywood's inner or outer surfaces cannot exceed 1". This leaves only ~1/4" available for the design of the metal "hard parts" that will engage with the frame, thus severely restricting the amount that the metal hard parts can protrude inward past the vertical plane of the frame's perimeter.

-Dick Ledford

[GaryVoshol]

Dick, you are misinterpreting <R07-L>. The rule is saying how much BUMPER-stuff can be outside the FRAME PERIMETER - it includes the noodles and fabric in "soft parts". There is no restriction on how much can be inside the frame.

[RRLedford]

Originally Posted by GaryVoshol

Dick, you are misinterpreting <R07-L>. The rule is saying how much BUMPER-stuff can be outside the FRAME PERIMETER - it includes the noodles and fabric in "soft parts". There is no restriction on how much can be inside the frame.

So as far as inward frame penetration of bumpart's hard parts, anything is allowed within the weight limits of the bumpers. That eliminates the mounting problem that I thought we had. Thanks.

-Dick Ledford

[Al Skierkiewicz]

Dick,
The 1" hard parts rule refers to any hard parts that extend beyond the frame perimeter not that intrude on the frame perimeter. This rule simply insures that a team does not construct their bumpers with fasteners that project beyond the pool noodles when hit. At all times, robot to robot and robot to field interaction must be shielded by pool noodles including the corners. See Fig 4-1.
As for the hardware/structure used to mount bumpers, the intent is that major robot structure is not moved to the bumper assy in order to bypass the robot weight limit and thereby increase the weight of the robot. Brackets, angles drilled and/or threaded, clevis and other attachments to hold bumpers in place will be weighed with the bumpers. Other structures that are meant to be robot structure will be weighed with the robot. This part of the bumper rules has not changed significantly in the past three years.

[gopatterson]

What is the height of the bumper

[Vikesrock]

Originally Posted by gopatterson

What is the height of the bumper

You already asked this question and got an answer in this thread:
http://www.chiefdelphi.com/forums/sh...ad.php?t=90814