Celt-X 5406 has a reputation for bringing “Everything but the kitchen sink” to competition. We don’t want to be unable to fix our robot because we forgot something at home! It’s a point of pride that our pit often becomes a bit of a “Home Depot” at competition when other teams look to us for missing parts. The flip side of that philosophy is that we need a lot of bodies to load and unload all of those containers and shelving, and sometimes that’s hard to find (such as in the middle of the workday for load-in, or late at night for unpacking).
To answer this problem, we have been dreaming of building a “SuperPit” (as popularized by teams like 973, 1678 and many others). Last fall, we were lucky to receive a large donation from a private sponsor which allowed us to get the project rolling. We finally finished construction last week, just in time for the Rainbow Rumble off-season event. We’re pretty proud of the result, and we’d like to share it with Chief Delphi. Presenting the Celt-X Superpit!
Specifications:
The Celt-X Superpit is inspired by other teams’ designs, but we had some unique design requirements (in particular the electronic banners and under-bus storage) that required something new.
- Size: Two cases, each 79” wide x 27” deep without lid (30” deep with lid) x 108” tall when extended (66” tall when closed and retracted to fit in trailer opening).
- Weight: Each case weighs approximately 500 lb empty (1000 lb with empty toolbox). Loaded weight is 1500 to 2000 lb.
- Disassembly and Bus Transport: The upper cases can be detached from the lower cases such that they can all fit into a 42” tall coach bus underfloor luggage bay.
- Storage: Capacity for qty. 8 of FRC standard totes (Orbis 65L), qty 8 of small totes (Home Depot 26L), qty 28 of 2.5" tall flat-pack organizer “tackle boxes”, and qty 1 of Husky 72” wide x 24” deep tool chest. We put a priority on keeping this storage arrangement flexible (using wood dividers, rather than dedicated metal racks) so that we can easily adapt them to future needs.
- Work Surface: 1.5” thick butcher block countertop (edges routered to 0.5” thick to fit road case extrusion), surface is 41.5” above the floor
- Bench Vice: countertop has embedded tee-nuts to secure a bench vice. (Vice must be removed and stored in the toolbox to allow the upper case lid to close).
- Power & Lighting: Upper cases are wired for 120 VAC using AC90 armored cable. Each case is equipped with qty. 16 of Nema 5-15 receptacles, and qty. 4 of 750 lumen dimmable recessed LED lights.
- Electronic Banners: Each case supports qty. 2 of 43” diagonal TVs driven by one Orange Pi single-board computer.
- Motorized Elevators: Each case has elevators driven by qty. 2 of 100W 12VDC electric linear actuators, each rated for 300lbf, that can raise the upper cases from 0 to 18” within 60 seconds. Each pair of actuators are driven by a Progressive Automations controller which uses potentiometer feedback to synchronize their movement and to store three preset heights.
- Casters: Each case is supported by qty. 6 of 600 lb rated, 6” diameter casters. Outer 4 casters are of the “total locking” type. Caster “track width” is 24” to fit within the trailer ramp.
- Towing Features: Each case has a recessed shackle on either end, tied into the elevator structure, used for winching the cases safely up and down the trailer ramp and to tie them down inside the trailer.
Design Details:
The Celt-X Superpit 3D CAD is available in Onshape here.
Drawings are attached below.
Note: Neither myself, Celt-X, nor any of the contributors to these documents make any warranty with respect to the accuracy or safety of the information, nor assume any responsibility for liability or damage that may result from it. These are heavy items which could accidentally hurt people, so please do your own diligence!
CX23-SP-A003 R1 top box drawing.pdf (2.6 MB)
CX23-SP-A002 R1 bottom box drawing.pdf (1.9 MB)
CX23-SP-A004 R1 dolly drawing.pdf (539.6 KB)
CX23-SP-A001 Road Case Stowed.pdf (1.8 MB)
CX23-SP-A006 Elevator Assembly.pdf (145.8 KB)
CX23-SP-A005 upper box beam assy.pdf (101.3 KB)
If I find some time I’ll upload a BOM and cost sheet later, but I can say that all in the project cost something around 15 k$ Canadian, about half of which went to the road case fabricator. * * corrected link * *
Lessons Learned:
Overall our first deployment of the Celt-X Superpit was a success! We were able to pack everything we wanted, got the cases in and out of the trailer and venue safely, and we were pretty happy with the ergonomics during the event. It was especially rewarding to receive a community award (pickles!) from team 2611 for the “Best Pit” at Rainbow Rumble. Thank you Jacktown Vectors!
There are a couple of lessons learned this weekend, which we’ll try to address during the rest of the off-season:
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Currently one case weighs close to 1000 lb, and the other close to 2000 lb. The heavier case is noticeably harder to move around, especially over obstacles like door thresholds and cable protectors. We will probably swap the upper cases to even out the weights.
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As the cases are winched over the peak of the ramp into the trailer, there’s a moment when the cart is only supported by the middle wheels. That is probably more weight than should be on two 600lb rated wheels. For this reason we are looking at upgrading the middle casters only to ~1000lb rating. We also had success jacking up the trailer tongue a bit more to reduce the “hump angle” at the top of the ramp.
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Similarly, when entering and exiting the ramp, the first two casters to hit the transition are subject to a hefty side load. To address this, we might weld up a steel tube “dolly plate” to attach the casters to, rather than the current ¾” thick plywood.
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Tying the elevators and hoist rings into the lower case in a structural way took a lot of care and thought. It works, but if we did it again, it might have been easier just to weld the entire lower case from steel like 973 (and others), and just have the upper box be built as a plywood road case.
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We are also planning a number of upgrades:
- Add removable safety pins to the elevator tubing to prevent it from falling all the way down if the actuators were to fail
- Add locking drawer slides to the tote case so that we can pull out and open any tote we want without having to remove any other first.
- We are considering adding a 12V power supply to the lower cases to power the elevators, rather than using an FRC battery.
- Add some hardware to the lower case lids so they can be used to form a corner “hutch”, as shown in the crayola CAD render.
- Add reasonably priced internet access in the pit so that we can display the event live stream on one of the TVs. This is a bit tricky when we’re in the US, but there are options.
- Add more content to the electronic banners, especially between events, such as RFID attendance, calendars and schedules, and kanban boards.
I hope by sharing these details we’re able to help other teams that might be looking at a similar project. Please don’t hesitate to post here or contact me directly with any questions or comments.
