I will add here, we had to cut a slot in our 2x4’s when making our robot cart to stay out of the way of our gearboxes. Since that’s the way the WCP DS gearboxes were mounted on our chassis. So depending on the gearbox you guys are using you might need to do that, or not.
KEEP IT SIMPLE!
Pit setups and carts have gotten out of control. Anything you take to an event you have to find a way to transport it and have manpower to set it up.
Just get a simple platform truck/cart with handles that fold down or that are easily removable. Use a pair of foldable saw horses to work on your robot in the pits. All these things can fit easily in someone’s trunk.
My priorities would be, in roughly this order:
- Make sure it will fit through a door!
- Large wheels for various ground obstacles.
- Make sure the robot won’t fall off when you’re turning sharply or traversing a bump.
- Fits in whatever you would normally use to transport your robot to events/demos.
- Comfortable, structurally-sound handle.
- Somewhere safe to put the driver station down.
- Place for a spare battery.
- Maybe a very small amount of tools storage.
Make sure it is transportable. I have seen teams using the carts with the hydraulic mechanism for raising and lowering the table surface. That is really cool but really heavy. Otherwise, start with a low deck so you can accomodate the tall robot that you will build eventually. On a past team, to raise the robot up, they put one or two grey totes on the deck of the cart. Those totes were used to transport materials to the events and were taking up pit space otherwise.
Bungee straps! I’ve seen a few bots topple, so I’m almost surprised this isn’t a requirement at events.
125 lbs is nothing for bungees to keep down, but it is quite a hazard with people around. (hey that rhymes!)
BTW, we just use a dolly and build a 2x4 bed to fit the bot.
I think 4 is recommended.
I see the DIY aspect of a cart, but a lot of teams don’t have time for that, much like my team. So we purchased this cart and it works so well!
We’re really happy with how our mini pit turned out! It includes a magnetic strip that holds all of our critical tools and enough room underneath to store extra batteries and anything else we might need while we’re loading onto the field or making a quick repair in the queue line. It also raises and lowers using a Dart Linear Actuator for convenience while working on the robot and safety while we’re on the move.
Our cart is one of those hydraulic lift carts. The lift feature was neat. The lift cylinder broke several years ago. We haven’t missed it. Most likely the wheels will overhang the cart. So it will need structure to support the robot. Actually a feature that makes it easy to work on and test the robot in the pit. Pros: Small base so it fits any where. Nice casters and capacity so we can use it for heavy things. (like batteries.) Cons: Heavy. No storage for other things. Like bumpers and driver station. We are thinking about a new cart. It will not be hydraulic.
A couple recommendations based on personal experience:
- Go for solid wheels (with an appropriate weight-rating), not air-filled tires. Source: we’ve had a cart tire pop at an off-season competition and hauling the cart around the rest of the day was miserable
- Make sure the bottom surface is properly braced to support the weight of the robot. Source: We once had a wooden-dolly style cart that sagged in the middle and eventually started scraping the floor; we reinforced it in the middle of Champs because we were worried it would break
- I recommend having two parallel pieces of 8020 on the top surface, with two pieces mounted on top of and perpendicular to them. This way you can adjust the width/spacing of the top two pieces each year to fit that year’s robot. Source: Several years of realizing that last year’s cart was custom-built to last year’s robot and building a new one, before we learned
Here is the best picture I have of our robot cart on my computer. A couple nice features are:
-Robot sits on 4 blocks that can be adjusted with holes on the top frame in .5" increments
-removable push handle
-2 fixed wheels and 2 swivel wheels
-space underneath for storing tools or for allowing easy access to the drive train underneath
-This cart was made back in 2012 (I think) and it is still working great
-The cart also integrates with our battery cart/charger so when we ship the robot in the crate the battery cart breaks down and fits into the robot cart to pack efficiently
I would recommend that you design it so that you can fit through the doors at your competitions. We had an incident where we had to modify our cart because it was to tall with our robot to fit through the doorways.
Our cart doesn’t fit through ANY door we are always lucky when there are double doors and we can go straight to the pit from the loading dock
I like simple. You can see me pulling the cart 3946 used from 2013 through 2018 on the street here:
It’s just a garden cart with some wooden side frames bolted on in 2015 and some “legs” so you can stand the cart on end in the pit bolted on the next year. Unfortunately, after six years the wheels had taken too much abuse. It was replaced this past summer with a new very similar cart (donated by a local Home Depot IIRC).
Hello! One of my teammates pointed me to this thread after we got an email about our cart.
That cart was built for us by a sponsor and mostly out of welded rectangular steel tubing. As such, I wouldn’t recommend building it exactly how we did. It’s also ridiculously heavy, well over 300 pounds (low estimate) so definitely make it out of different materials. But being able to adjust the arms closer/farther apart and higher/lower from the ground is SUPER handy especially between years with different drive trains.
Eventually, I’m going to put together a CAD model of that beast but until then pictures will have to suffice. I’ll try to post some on our website soon!
pugsly14 do you know if there are any other better options, I’m trying to do some research and find the best model for a similar price.
We actually had it donated. I found it listed on Facebook marketplace and told the guy what we were going to use it for and he donated it. We took the rubber top off it, and put a on a wooden top, painted it black and used some 80/20 on the ends to prop up the robot to keep the wheels off the ground.
I don’t know if it was actually from harbor freight but it was the closest thing I could find that looked exactly like it when I did a google image search.
Ok, something we were running into was the fact that it was going to be too heavy, we were trying to do a similar approach to @Ginger_Power 's design.
Hey @pugsly14 check this out this should be similar and cheap to what you want, all you need to do is slap a small toolbox on, just enough to hold quick repair tools, duct tape, radio communication cords stuff like that, you can also just slap on two pieces of square tubing, 80/20, 2x4s, your choice.
This is a relatively decent size for competitions for what you want, you could possibly even build around the small toolbox and have your drivers station on top or rest on the toolbox in general. Hopefully this is cheap and sturdy enough for you. Yes it’s rated for 1,000 pounds an unnecessary amount of weight above what you need but it is a good size for what you want. Yes it is $260 but based on what it can do it is worth every penny. https://www.harborfreight.com/1000-lbs-Capacity-Hydraulic-Table-Cart-60438.html