Step 1: Concept & Planning
Step 2: Materials
MDF (swing arm)
Bearings: 26x10x8 mm
Aluminium (gear-axle connection, brackets)
Sheet Acrylic (gears)
Styrene (guide plates)
Tin Cans (vessel)
10mm Steel Rod (axle)
Plastic Robotics Gearbox (Maplins)
24V Motor & Power Source
Step 3: Constructing the Frame
1. Cut the required lengths (as measured from our general arrangement drawing) of pine
2. Drilled holes for the bearings
3. Clamped into desired form to prepare for fastening.
4. Fastened together using wood glue and screws (hand drill), into a form of A-frame (as shown in SolidWorks image)
5. Repeated for other side of frame.
Step 4: Adding the Swing Arm
This is how we constructed it:
1. Marked the curved shape onto a sheet on mdf
2. Cut using band saw
3. Drilled 10mm holes spaced 100mm apart along the swing arm
4. Drilled one 26mm hole at one end of the arm for the bearings
5. Repeated for second swing arm
Step 5: Attaching the Cups to the Belt
2. To do this we made five brackets by cutting and bending 3mm thick sheet aluminium.
3. Drilled two holes in each bracket for attaching to belt
4. Drilled two more to use with zip ties
5. Fastened to belt using small bolts countersunk into spaces between the teeth, equidistantly around the belt.
6. Attached the cups to the holes in the brackets with the zip ties
Step 6: Making the Gears
1. Measured the spacing between the teeth on the belt with digital callipers.
2. Used SolidWorks to draw out a stencil for the gears
3. Laser cut this shape out of 4mm sheet acrylic (x8)
4. Cut a rough spacer plate out of foam to place between two of the gears (x4)
5. Cut two guide plates out of 2mm thick styrene, for either side of the gear sets. This was to insure that the belts wouldn’t slip, causing the system to fail.
Once we had made these gear ‘sets’ we had to find a way to connect them to the axle without slipping. To do this we had four aluminium lathed parts that would effectively allow us to grub screw the gear sets to the axle. These are also shown in pictures below.
Step 7: Assembly of System
1. The bearings were push fitted into the holes on the frame
2. Gear sets fastened onto axles
3. Belt configuration placed onto gear sets
4. Axles slid into bearings, into frame
5. Swing arm locked into place with aluminium rod
We then placed the system into the tank to check that everything was ready for testing.
Step 8: Motor and Gearbox
1. We sourced a plastic robotics gear box (from a Maplin store) to allow the motor to turn the axle.
2. The gear ratio we were looking for in order to turn our axle was 260:1, which this gear box provided.
3. We then connected the motor to the gear box and mounted this to a piece of MDF.
4. This was then lined up and the motor shaft was grub screwed to the axle.
5. The whole system was then mounted to the frame.
Step 9: Finale
Unfortunately the robotics gearbox failed us as the little plastic gears couldnt handle the amount of torque we required and started to shear. By the time of the event we were still unable to fix the gearbox, however we did manage to run the pump by connecting a hand drill directly to the axle. Here is a brief video of the pump in action.