The open/close manipulator is useful tool to retrieve small objects or attach a line to objects located underwater.

The jaws of are driven by the electric screwdriver. Using electric screwdriver has many advantages:

Easy available

Cheap, cost about 5€.

Powerful - 2.4Nm

Planetary gearbox

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.

Details

Top view

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.

Dimensions