Which one is better to use in Toss Up and why? Chain Bar and 6-Bar. One has less metal usage, while the other one is stronger.
Which is the perfect one for Toss Up?
How exactly does a chain bar lack height? It can extend vertically, giving it more height than a six-bar of the same length.
Chain bars are good for lighter loads that will not break, but if you need a strong lift that extends to the vertical position, I would go for a vertical 4-bar like 24B.
We like the 6 bar (Owen and I) because it puts the cog more forward. If our current toss up robot had a chain bar it would be way too back heavy.
I have yet to see a real 6-bar that can extend to that height, and remember that the end of the yellow bar is where the intake would be, not the green. The “true” height of a lift is the height that it can deliver game objects to.
As for max height, you can attach a bar to the end of the chain arm and it will be as tall as that unrealistically raised 6-bar is. A real 6-bar would be shorter than that.
Remember, a 6 bar can always go vertical if you make it so. It just takes some planning…
The top part of the 6 bar is useful for hanging this year, although there’s nothing stopping you from adding an attachment at the end of a chain bar. I like that the 6 bar has more potential for varying the angle of the intake, whereas with the chain bar, you can only make the intake rotate in one direction.
I would say 4 or 6 bar because I dont like the slop in chain bars( it can be minimized but will still be present. The height is not an issue. Either type will get hight enough if you do some work.
Neither 
I would go with a chainbar
Before someone chews me out on this, this was done at a quick glance, so someone please check my work. Looking at the weakpoints of each system, the chain bars chain and the 6 bar’s axles, Both systems are pretty weak. The chain bar has a theoretical resistance of 50 pounds. Add 2 pieces of chain and you get 100 pounds. However, add the radius of a standard sprocket paired with a 5:1 ratio, you get around 90 inch pounds of torque it can withstand. if you get your rollers that are maybe 5 or so inches away from your intake, the chain will snap at 18 pounds of force, a force that’s almost half the typical force a drivetrain can give. With a linkage, there are usually 4 joints of interest. Each joint can handle 118 pounds, so multiply that by 4. Thats 472 pounds of force it can handle. Divide that by the length of the lift (probably 14 inches) and u get about 33 pounds of force the system can handle. Divide that value further by the length of the axle(usually 1.5 or so), and it gets to about 22 pounds of force.
So really, your best bet is to reinforce the systems. More reinforcement means more metal. Add on the metal to the 6 bar linkage and you already have the weight of a chain bar and another system. Other than reinforcing your systems, you can add shields on your drive train to semi protect your lift. At least protect your lifts while the intake is down. Plus, your lift should be down for the most part. Once you score your buckies, you would back up and lower your lift. When finding balls, your lift would be lowered. A goal is practically everywhere, so you don’t need to spend much time with your lift in the air. You can add sheets of lexan to protect your chain while your lift is in the air.
Another factor to consider about less weight means more available power on drivetrains. Less overheating becomes a plus, higher potential speed is a plus. If you want a slow drivetrain anyways, u can dead weight the drive and make your cob extremely low. You can also add more metal onto your intake to protect the motors. With a bent axle on the lift, you at least have the chance to raise your system. If your motors are attacked during a match, you can lose your whole method of scoring
As for backlash, the chainbar only needs to score at one height. Add a standoff to fine tune your height and slop won’t matter. Sure, there’ll be slop when getting to the height, but the only time that slop hurts is the height to score in the column goal, which is then fixed.
As for center of gravity issues, if your chain bar is about 16 inches long, you can simply add more systems to the lift, fixing your cob. if your chain bar is 12 inches long, you can move it closer towards the middle of the drive, giving you room for electronics and other systems. Plus, you wont bury your cortex in metal. By simply adding more systems which can help your robot, you kill 2 birds with 1 stone.
More things to consider
-As of now a chain bar is less common, helping you stick out in judging
-Even if you apply combination gearing to 6 bars, you risk twisting your axles
-Combination gearing loses a lot of power. About 70% each stage according to my calculations
-Chain bars require less maintenance between matches and things are easier to access
-Cutting metal is common with 6 bars. If your team has financial issues, that could be a bad call
-single chain bars reduce any need to manage uneven power levels on lifts
-A single sided 6 bar may limit your mechanisms to claws and scoops
-Zipties connecting the chain can reduce points of weaknesses
-Nothing’s stopping you from adding more pieces of chain to reduce the chain bar’s vulnerability
-Added systems can be used to further protect the chainbar. Additionally, their characteristics can be significant in helping you play the game
-You’re more familiar with chain bars than 6 bars
This is untrue, you can vary the rotation of the intake on a chain arm by changing the sprocket sizes. Because if this, it is easier to get drastic change on a chain arm.
Hey guys,
I’ve been asking myself and you guys the same question: Chain or 6 Bar?
The key is all about the longest bar in each design,
What I mean by this…
For the 6 bar there is that center bar that is the longest. It depends on that length to determine the max height for the 6 bar
Now for the chain bar it’s the same thing…
It all depends on that longest bar.
I did some basic math: Finding the Hypotenuse of a 18" x 18" robot and a 18" x 12" robot and I calculated that
18" x 18" = theoretical possible height = 43.45" (if completely vertical)
18" x 12" = theoretical possible height = 33.6" (if completely vertical)
Now these numbers are for both a chain bar and a 6 Bar but that’s only if the arm goes totally vertical…
I’ve worked with 6 Bar’s and they do not go totally vertical because the metal pieces come in contact with each other towards the top.
I haven’t had a lot experience with Chain Bars but I can see in videos that they could go totally vertical and over to the opposite side if there wasn’t anything stopping it.
So theoretically the chain bar gets the max height…
Now if your talking about strength and quality then thats a different story…
Everyone:
You can build a four-bar or six-bar that can go completely vertically (and backwards, if you want) just like a “chain-bar.” Given that the smallest sized high strength sprocket with holes in it had a larger diameter than the width of a piece of VEX metal such as a c-channel, a six-bar would be able to have a longer (middle) bar, and therefore reach higher.
That being said, a four-bar can reach enough to hang with a 12" tall robot, but it is more difficult.
~Jordan
In fact, you can make a vertical 6 bar without even horizontally offsetting the bars, conserving width… it depends where you place the joints.
Pretty sure you misread/misunderstood what I said.
Would you mind explaining, then? I took your post to mean that a chain-bar has less potential to change the intake angle as it goes up, like an offset, nonparallel six-bar can. Did you mean something else?
If you guys could show me a picture or design I would love to figure out how to do this…
Which part a,
- 4 bar that can reach the hanging bar
-or the 6 bar that can go vertical
-both?
Well I’d like to see both haha
Me too! 
Chain bar can have a larger overall variation, that’s true. This year, our bucket started level with the ground. When we raised to descoring height, the bucket would tilt so that the front was a little above the back, to allow for catching descored sacks. Then, at scoring height, it would tilt so that the front was below the back, so that sacks would dump out more easily. We did this by changing quadrilateral sizes on the 6 bar. With a chain bar, the rotation occurs in the same direction and the same rate for the entire motion
For vertical 4/6 bar, if you move the bottom bar in front of the top bar, perhaps by using pillow blocks, then the linkage can go vertical