Grabber
The grabber is useful tool to retrieve small objects or attach a line to objects located underwater.
Grabber
The jaws of the grabber are driven by the electric screwdriver. Using electric screwdriver has many advantages:
- Easy available
- Cheap, cost about 5€.
- Powerful - 2.4Nm
- Planetary gearbox (low quality)
Because screwdriver is extremely cheap you can consider not to isolate housing! Just buy another one when water damages it. Tests in real environment shows that after a few divings it still works.
Battery part of the screwdriver have to be removed. Model shown on the pictures fits 50mm PVC pipe. Front and back caps are made from Plexiglas. Two simmerings are used as water isolation on front cap.
Electric screwdriver: Torque 2.4Nm, power 6V, Cost 5€.
Engine without battery pack
Front cap with simmerings
Disassembled engine housing
Engine housing: Top view
Grabber part
Engine and front cap
Grabber top view
Grabber
Grabber
Gripper model: Device used to test gripper designs.
Grabber side view
Grabber
Grabber: Jaws only
Grabber
Grabber rear view
Grabber
Grabber and hand
Details
Grabber Diagram
Grabber decomposed
Grabber decomposed: Bottom view
Description
Please note, size of the elements is not critical. Availability was the main criterion.
1. Jaws × 2; 10mm Plexiglas
2. Threaded rod Ø8mm × 1; metal
3. Nut assembly × 1
4. Washer × 4
5. Bolt × 4
6. Link actuator arms × 4; aluminum or steel
7. Pivot bush/mount Ø10mm × 2
8. Bearing assembly × 1
9. Simmering sealed front cap × 1; Plexiglas, simmering×2
10. Motor housing; PVC pipe ø50mm × 1, size depends on motor size
11. O-Ring sealed motor housing end cap × 1; Plexiglas + o-ring
12. Nut × 4
13. Compression plate × 1; steel or aluminum, lathe work
14. Washer × 4
15. Studded bar × 4
16. Pivot mount bush Ø8mm × 4
17. Compression plate/mount × 1; steel or aluminum, lathe work
18. Bush × 4; steel or brass (the best)
19. Nut insert × 4
Elements that are permanently connected:
- 18+1 (epoxy glue)
- 9+10 (epoxy glue)
- 5+19 (epoxy glue)
If you are able to use steel as material of the jaws you do not need to use parts 18 and 19. Instead use an ordinary nut.
Corrosion of steel is ignored in this design. Total time in water is relatively short, so paint should be sufficient protection. Another solution is to use stainless steel.
Jaws
In the last step permanently attach sleeves.
How to make jaws
Dimensions
Grabber dimensions
