Introduction: Rowing Prosthetics
Hello and welcome to the Cambridge Bio-Augmentation System’s OpenSource rowing prosthetic. This project was born out of John Willis’ Road to Rio Challenge, where he participated in every Olympic and Paralympic sport in the lead up to the Rio 2016 Olympics/Paralympics. He wanted to show that sport doesn’t have boundaries and no matter the impairment, able bodied and impaired people can inclusively play together. So it is very fitting that the devices that we designed to help John hold sporting equipment, we are now releasing into the public so that true to John’s goals, the boundaries of sport are eliminated.
Step 1: Design Notes
• Oar Type
– These devices will mount onto a concept2 oar.
• The stroke
– If any of your amputations is above the elbow then you will be rowing with torso only. For anything below the elbow these designs will allow you you to row arms and torso.
– These devices won’t allow you to feather.
• 3D Printing
– The minimum printer requirements are:
– Print Material (in order of preference): PLA, ABS
Bed Size: 150mm x 150mm x 140mm (height)
Printing Resolution: 0.2mm
Shell: Thick (2mm)
Infill: 30%
– We recommend looking on https://www.3dhubs.com for printers that can make these parts at a low cost.
Step 2: Selecting Your Devices
D.A.R (Design Alteration Required)
– In theory these devices could be used by people with this amputation level, however alteration to the design file will need to occur before they can be used. This is because, on an oar there are different diameters in grip size (left and right side) so the print files will need to be edited to have the two grip sizes available (instead of just the one, as it is now).
- By building the following designs, the variations in the table that don't show D.A.R can be used without alteration.
Step 3: Row Hoop
Step 4: Labeled Device: Row Hoop
1- Bike Handlebar Tape
2- Metal Hoop (Search www.fhbrundle.co.uk for “round section circle”)
- 100mm diameter
- 8mm rod diameter
3- Bike Inner Tube (2x)
- Cut to 60mm x 90mm
4- Clamp Runner Component (3D Printed Part)
5- Clamp Component (3D Printed Part)
6- M5 bolt (4x)
- Fully Threaded
- 50mm
7- M4 bolt (4x)
- Fully Threaded
- 15mm
8- Arm Curve Runner Component (3D Printed Part)
9- Arm Curve Component (3D Printed Part)
10- 5mm Foam
- Cut to 50mm x 90mm
Step 5: Row Hoop STL Files
Step 6: Manufacturing Row Hoop
- Glue one of the pre cut inner tubes to the clamp runner component.
- Allow to cure
- NOTE: The clamp runner is distinctively different to the arm curve runner. You are looking for the part that has the nubbins protruding from the external curved surface.
Step 7: Manufacturing Row Hoop
- Tap the arm curve runner component with a coarse M4 thread.
- Glue the other pre-cut inner tube to the clamp runner component.
- Allow to cure.
Step 8: Manufacturing Row Hoop
- Tap the arm curve component with a coarse M5 thread.
- Glue the pre-cut foam to the arm curve component.
- Allow to cure.
Step 9: Manufacturing Row Hoop
- Wrap bike handlebar tape two thirds of the way around the metal hoop.
Step 10: Manufacturing Row Hoop
- Using the M4 screws, attach the arm curve runner and clamp runner components to the oar.
Step 11: Manufacturing Row Hoop
- Slide the hoop onto the oar so it sits with the exposed metal section against the centre of the clamp runner component.
Step 12: Manufacturing Row Hoop
- Put the clamp component on the clamp runner component, ensuring the hoop fits into the slotted section and the nubbin fits into the recess.
Step 13: Manufacturing Row Hoop
- Slide the arm curve between the hoop and arm curve runner, then fix together with the M5 screws.
- The screws should be tightened so that the arm curve and clamp are able to rotate around the runner components.
Step 14: Row Hoop Full Assembly and Use
• Setup
– The instructions you have followed in steps 5 to 9 indicate how the device attaches to the oar however, to keep this simple we didn’t include how to set up the positioning. The nubbins identified in step 1 must be orientated so that the hoop is facing towards you. The purpose of these is to act as stoppers and give more control over the oar (specifically the blade flipping).
• To use the device, simply slide your residual limb between the hoop and arm curve, and pull on the hoop.
Step 15: Row Ball
Step 16: Labeled Device: Row Ball
1- M5 bolt (4x)
- Fully Threaded
- 50mm
2- Clamp Component (3D Printed Part)
3- M4 bolt (4x)
- Fully Threaded
- 15mm
4- Clamp Runner (3D Printed Part)
5- Bike Inner Tube (2x)
- Cut to 60mm x 80mm
6- Housing Runner (3D Printed Part)
7- Ball Component (3D Printed Part)
8- Metal Rod
- dimensions to be determined in steps 24 to 26.
9- Housing Component (3D Printed Part)
Step 17: Row Ball STL Files
Step 18: Manufacturing Row Ball
- Glue one of the pre cut inner tubes to the clamp runner component.
- Allow to cure
- NOTE: The clamp runner is distinctively different to the housing runner. You are looking for the part that has the nubbins protruding from the external curved surface.
Step 19: Manufacturing Row Ball
- Tap the indicated holes with an M4 thread.
- Glue the pre cut inner tube to the housing runner.
- Allow to cure.
Step 20: Manufacturing Row Ball
- Tap the indicated holes with an M4 thread.
Step 21: Manufacturing Row Ball
- Locate the clamp runner and housing runner components on either side of the oar shaft.
- Screw the components together with the M4 bolts.
Step 22: Manufacturing Row Ball
- Locate the clamp and housing components on either side of the oar shaft.
- Screw the components together with the M5 bolts.
Step 23: Manufacturing Row Ball
- Cut a thread in the metal rod so it attaches into your socket (please see your prosthetist for thread dimensions).
Common threads are:
- UK made prosthetics- 3/8 inch Whitworth.
- US made prosthetics- 1/2 inch.
- EU made prosthetics- M12.
Step 24: Manufacturing Row Ball
- Fit the row ball device to the oar (and fit the row hoop if your amputation requires it).
- To do this next bit you will need to be sat in a boat with the oar in front of you.
- If you are a unilateral amputee, then the oar should be held at your intact arm’s length.
- If you are using a row hoop, then the oar should be held at elbows length.
- If you are using a dual row ball, then the oar should be a comfortable distance.
- While in the position measure between the end of your socket and the inside curved surface of the housing (shown in the image).
Step 25: Manufacturing Row Ball
- Minus 11mm from the measured number. Mark this new measurement on the rod when measured from the top of the threaded end (shown in diagram).
- Cut the top 18mm on the non threaded end to Ø9.5mm (as shown in the non shaded section of the image).
Step 26: Manufacturing Row Ball
- Glue the ball component to the 18mm, Ø9.5mm section created in the last step.
- Allow to cure.
- NOTE: Your rod may not look like the image shown however, if it fits the ball, fits into your socket, and is the right length, you have done everything correctly.
Step 27: Row Ball Full Assembly and Use
• Setup
– The instructions you have followed in steps 21 and 22 indicate how the device attaches to the oar however, to keep this simple we didn’t include how to set up the positioning. The purpose of the nubbins identified in step 18 is to act as a stopper and prevent the housing from dropping and becoming unreachable when the ball is disengaged. Thus the nubbins should be located to prevent this.
• The metal pylon is designed to slide in and out of the housing to disengage and engage with the devices.
Step 28: Additional Information
• Liability
–Cambridge Bio-Augmentation Systems does not accept any liability in relation to these devices, or any of their remixed variations. Any breakage, injury or death are solely the risk of the user and by manufacturing you agree to relinquish Cambridge Bio-Augmentation systems of any responsibility.
• The OpenSource license
–These devices are released under the creative commons license: attribute – noncommercial – sharealike.
• Contact
•Any quires please contact contact@cbas.global
