Laser Cutting a Hydraulic Crane

Let's build a crane! Why?? Cause cranes are awesome!

Okay, so what do we need in order to build this crane?? Well first of all we need building materials! Let's make a list!

Materials:

1. MDF (a plate measuring 600mm * 400mm *6mm should suffice)
2. 2 x 20mL plastic syringes without needle
3. A tube that fits the nozzles of the syringes
4. Strips
5. Thread
6. (Glue - not a total necessity)

Aside from the building materials we will also need access to the following machines:

1. A computer with software like, SolidWorks, Adobe Illustrator, Inkscape or something similar capable of producing a drawing of the crane layout for the laser cutter.
2. A laser cutter.

Alright! Now that we got everything we need let's get started.

Before we can start laser cutting, we first need to plan a design, then we have to sketch it up using software capable of exporting a file that is compatible with the laser cutter we are using. There are many ways to solve this. A good idea is to build quick mock-up models in order to test your design before laser cutting the final design.

Feel free to use these drawings for inspiration, or download the attached "hydraulic_crane.dxf"-file in order to continue straight to the laser cutting.

Good! Now that we have a design, it is time to use the laser cutter to cut the MDF plate. Load the file with your design with the laser cutter software. There are many different laser cutters and a lot of different software for using them, so if you don't know your way around the machine, make sure you get someone who knows it to help you!

After laser cutting the MDF plate, we are left with a lot of crane-parts, so now it is time to assemble the whole thing!

In this design we are using cut-outs of the MDF as "locks" so the crane won't fall apart.

1. A syringe "controlling" the crane arm is placed and locked between the two sides of the crane.
2. Place the "side"-pieces on the "foot"-pieces (apply glue if you feel the construction is unstable).
3. Then take the two "arm"-pieces (make sure you lock them together with the "locks"), with a washer on each side and mount the cut away area on the "controlling" syringe, and place the arm so that the hole on the arm is parallel and concentric to the holes on the "side"-pieces.
4. Guide the second syringe through the holes, so it can function as the rotary shaft for the crane arm.
5. Mount the tube on each of the nozzles on the syringes (strips can be used to tighten the tube's grip on the studs further, if it seems to be necessary).

That's it job done!...But wait a minute, what about the hydraulic function?!?! Riiight, almost forget! Let's take a look at that in the next step.

Alright, since this setup doesn't allow us to use "real" hydraulic fluids, we are going to substitute with water.

1. Now disconnect the tube from one of the syringes.
2. Slowly fill the other syringe (as well as the tube) with water, while making sure no air bubbles is allowed into the system.
3. Reconnect the tube to the syringe (the one without the water). NB!: Make sure that the syringe plunger is pressed as far down the syringe barrel as possible.

Now when you pull one syringe plunger, the other syringe plunger will retract as well, and vice versa when pushing the plunger.

Now the crane should be ready for testing!

It is also possible to tie a plastic bottle, filled with water, sand or whatever, on the back of the crane arm in order to use as a counter weight, allowing the crane to lift a larger weight!

Congratulations, you now have a fully functional hydraulic crane, good job!!

Okay, now that the crane is done and fully functional, you can sit back and relax.

But then again, you might be left with thoughts like:

"Wow this crane is awesome, I had a real fun time building it! I wish it wasn't over already..."

or

"Okay this is cool, but what now, can't we step it up a notch and take it even further?"

Then don't worry!!! Cause, what if we mounted an electrical motor on the crane to control the crane movement? Wouldn't that be cool??

If you're up for the challenge keep on reading

Okay, let's take a look on what we need in order to upgrade our crane!

Materials:

1. MDF (450mm*400mm*6mm)
2. A 20mL plastic syringe without needle
3. A DC motor (measuring ø24.5mm) + threaded spindle (measuring 12.5mm with ø5mm)
4. An electrical switch
5. A 9V battery
6. Wires, different colours
7. Soldering tin
8. Acrylic plastic plate (450mm*450mm*5mm, should suffice)
9. Threaded rod (300mm long with ø7.85mm)
10. 7 nuts that fit the threaded rod

Machines:

1. A computer with software like, SolidWorks, Adobe Illustrator, Inkscape or something similar capable of producing a drawing of the crane layout for the laser cutter.
2. A laser cutter.
3. Soldering station
4. Plier cutter

Alright! Let's continue.

Once again there are several ways to solve this. Feel free to use these drawings for inspiration, or download the attached "motor_chassis.dxf"-file in order to continue straight to the laser cutting of the MDF parts.

(Optional): Designing the switch house

This step is not a total necessity in order for the crane to work, it just looks good, and since we need the bearings in acrylic plastic, we might as well design an acrylic box to function as the switch house. In this case we are using a flip switch. If you want to, you can feel free to use these drawings as inspiration. You can also use the "bearings_and_switch_box.dxf" if you want to.

Prepare the motor and the switch by soldering wires on each of them, making it possible to connect the setup to a 9V battery.

Our setup allows us to rotate the motor clockwise or counterclockwise by flipping the switch.

Now we need to assemble the motor chassis and the switch house and mount it on the crane.

Good job!! Now your brand new motorized hydraulic crane should be working and ready for testing!

Have fun!!!

NB!: We had some minor issues with the DC motor not connecting properly to the gear on the threaded shaft, due to a lack of time, we haven't been able to fix it yet, but we think making adjustments to the motor chassis in order to fixate the DC motor better, is the way to go!

(However we got the crane to work by fixating the DC motor with our hands)