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Picture of 2-Handle Hydraulic Arm Controller
Grabber closeup.JPG

Plywood Hydraulic Arm with Two Control Handles

I was so impressed with the cardboard hydraulic arm by Technovation

(https://www.instructables.com/id/CARDBOARD-Robotic-Hydraulic-Arm/) that I built one of my own from plywood, with some small modifications:

  • I wanted to have more grip on the arms, so I moved the pivot point. (see photos)
  • To get neater and stronger linking wires, I used bicycle spokes. Disadvantage: they are very strong, and small bending errors cause the arms not to meet in the middle. - Note that I had to bend one of them to make the arms meet.
  • I used a round base and disc shaped retainers on the ends of the bamboo skewers to hold them in.

I won't re-hash this construction, as it was very well covered in the instructable.

I have seen other versions of hydraulic arms with 4 controller handles, but I wanted one where the operator could have their hands on both handles and control the 4 functions of raising & lowering, slewing & grabbing without the need to let go of the handles.

Up & down movements are controlled by pushing the handles back and forwards

The grabber is engaged by a sliding pull-up handle within the left controller

Slewing left and right is done by see-sawing the control handles left and right.

I have attached a video of it working:

Step 1: MATERIALS AND TOOLS:

Bill of Materials:

7mm plywood 300 x 300 mm

Wood: ( I used radiata pine)

1 x 15mm x 115 x 70mm

2 x 20 x 40 x 140mm

1 x 20 x 40 x 63mm

1 x 30 x 65 x 100mm

2 x 30 x 45 x 60

1 x 16mm dowel x 135mm

1 x 16mm dowel x 260mm

2 x 16mm dowel x 60mm

1 x 16mm dowel x 59mm

8 x 10cc syringe bodies. On Ebay 6 for $1.39(us)

2 metres of Aquarium air tube

1 x bicycle spoke (U- connector on the moving handle)

Screws, panel pins, PVA wood glue

2 x Rubber bands,

4 x 2.5mm bamboo skewers.

Nails, screws, pva glue.


Essential Tools:

Hammer

Saw

screwdriver(s)

Ruler

Drill & bits up to 25mm

Side cutters, pliers, vice

Files/rasps (round and square)

Sandpaper

Extra tools (make the job easier)

Drill Press

Hole saw with 5/32 centre drill

Band Saw

Coping saw