The James Dyson Foundation Engineering Box – Lesson 7

Tangle-free Turbine Tool Disassembly Steps and Questions

Steps / Questions
STEP 1
Look at the Tangle Free Turbine head, move the neck back and forth and lightly pull on the soleplate. The neck attachment and soleplate move separately from the main body and each other – they actuate on external pivot points. / Q: The neck attachment and soleplate move separately from the main body and each other – they actuate on external pivot points. Why do you think this is?
Q: Why would Dyson engineers use pivot points instead of screws?
STEP 2
Now look at the same four pivot points on the sides of the turbine head. Insert a coin under the pivot point closest to the cleaner head’s turbine to gently pry away the top grey plastic part from the cleaner head. Repeat this process at the pivot point on the other side of the cleaner head to separate this piece from the cleaner head. This might take a bit of pressure – don’t worry, you won’t break it!
Next, look at the base of the neck and notice the seal. It has a very thin plastic coating. Then look inside the neck. There’s a bar that dissects the duct vertically. / Q: Why did Dyson engineers design a bar to divide the neck?
Q: What purpose does the neck seal serve?
STEP 3
Look at the pivot joints on either side of the lower grey plastic part (the soleplate). Again, use a coin to gently pry the grey soleplate away from the clear plastic housing of the cleaner head.
Once the soleplate is removed, notice the 45-degree channels at the front. Then flip the cleaner head over and look next to the pivot point on the left. The Dyson name appears with a set of letters and numbers.
Now look at the main body. Search the bottom for a tiny flat spring. The soleplate is spring-loaded, allowing it to maintain a seal with the floor while moving across crevices and various floor types. Look at the spring from the side and notice the retaining detail – the spring is held securely and won’t drop out. / Q: What are the identifying marks on the back of the soleplate for?
Q: What function do the channels at the front serve?
STEP 4
Next, take a T8 screwdriver and remove the four screws at the top of the tool. Place these in a cup or container. Once the screws have been removed, the top half of the tool can be pulled apart from the bottom.
Looking down at the top plastic piece of the Tangle-free Turbine tool, identify the circular lint filter. It sits atop the red turbine head. From the side, observe the clear plastic blades directly below the lint filter. These are the guide vanes. They direct the airflow entering through the lint filter so that the air hits the blades of the turbine at an angle. / Q: Why is the main housing transparent?
Q: What is the purpose of the lint filter?
Q: Why did Dyson engineers design the guide vanes to turn the air?
STEP 5
Turn the housing over – the part with the turbine still attached – and, looking past the counter-rotating paddles, remove the two screws from the main housing; one is located in the middle, behind the counter-rotating discs, and the other is located off to the side. Places these screws in your cup or container.
Now, you can separate the two halves of the gear train: the lower piece has the two large gears that spin the paddles, and the top half, which is the gear assembly. Be careful handling the gear assembly, as one of the grey gears is loose and may fall off.
Turbines are simple but extremely precise. The airflow enters through the lint cover and guide vanes, directing the air to hit the blades of the turbine and making the turbine spin, which creates continuous power. A shaft inside the turbine housing links the turbine to the main gears at the bottom. This is the main drive.
Looking down at the top of the turbine, notice the minimal gap between the edge of the blades and the internal housing, as well as the black rubber over-molded gasket or seal. The turbine relies on a sealed system to force as much airflow through the blades as possible. Air is like water; it will always take the easiest path. So it’s crucial to minimize any “escape routes” around the turbine.
Turn the red turbine and observe how the black turbine gear underneath turns. Then turn the turbine gear and observe how the red turbine turns. You’ll notice that they turn at different rates. / Q: What is the purpose of the duct?
Q: Why does the turbine spin at a different rate than the turbine gear?
Q: What are the advantages of a turbine versus a motor?
STEP 6
Return to the main body and notice the loose compound gear that connects to the two main gears. Slide this off of the rod pin. Make note of the tiered gears and the cut of their teeth as well as the material of the gears. Compare this material to the material used on the two main gears. How would you describe the difference?
Pick up the turbine assembly again and look at the tiny black gear and its relationship to the intermediate gear. You can place the intermediate gear in the circular area next to the black cog and observe how they spin together.
The turbine can spin at a rate of 20,000 RPM, but the desired rate for optimal performance of the bristle heads is only 3,500 to 4,000 RPM. / Q: Compare the teeth on the various gears. What’s different and how does this impact the function of the tool?
Q: How did Dyson engineers reduce the RPM to fit the target range?
Q: What material are the two main gears made out of? Why is this material important?
STEP 7
Return to the turbine assembly and remove the bottom screw. This allows you to pull off the J-shaped piece and gain access to the inside of the duct.
Notice the gaskets on both the outlet and the exposed interior. Also observe the raised bit of plastic that housed the screw – the screw boss. Note the shape of the screw boss. / Q: Why is the J-shaped half of the duct removable?
Q: Why is the screw boss shaped like a teardrop?
STEP 8
Move back to the bottom half of the tool. Flip it upside down to reveal the bristle head discs. Before removing the discs, observe the color of the bristles and the shape of the discs.
The bristles on the Tangle-free Turbine tool are made just like a toothbrush. A bristling machine bunches the bristles into a long strip, puts a tiny metal staple in the middle and fires it into the hole. This holds the bristles in place.
These bristle head discs are held in place with Phillips head screws. This is the only place on the Tangle-free Turbine tool where this is the case. Now use a Phillips screwdriver to remove the two discs from the main housing. Place these screws in your cup or container.
Observe the underside of the paddle, noting how it’s been designed so that it’s impossible to reattach the paddle to the tool facing the wrong way. This is an example of “poka-yoke” design. This Japanese phrase means “fail-proofing.” / Q: Why are the bristles red?
Q: What is the function of the bristles and what are they made of?
Q: Why might the discs be made of rubber?
Q: Is there a reason why the bristles are not circular in shape?
Q: Why do the discs counter-rotate?
Q: Why did Dyson engineers utilize Phillips head screws on these discs and not on other parts of the tool?


The James Dyson Foundation Engineering Box – Lesson 7

Tangle-free Turbine tool Disassembly Questions and Answers

Questions / Answers
STEP 1
Q: The neck attachment and soleplate move separately from the main body and each other – they actuate on external pivot points.
Why do you think this is?
Q: Why would Dyson engineers use pivot points instead of screws? / A: The neck and soleplate pivot to maintain constant contact with the surface of the floor, ensuring no suction power is lost. The neck pivots to maintain contact with the floor while the machine is moved backwards and forwards. The soleplate has a spring-loaded pivot to allow the turbine head to glide across all floor tops, without losing contact with the floor.
A: Pivots are actuating joints – which means they can move around. Screws are more static, they are fixed joints. Pivot points also allow engineers to minimize costs since the pivot is created as part of the single moulded part.
STEP 2
Q: Why did Dyson engineers design a bar to divide the neck?
Q: What purpose does the neck seal serve? / A: The neck splits the airflow coming from the machine between the turbine (which drives the brush heads) and the suction at the brush heads to suck the dust and dirt away. Airflow balance is crucial. Too little airflow and the discs won’t spin quickly enough to suck up debris. Too much airflow and the discs spin too fast to capture the dust and dirt. More airflow to the turbine also means less suction for the rest of the cleaner head.
A: Is seals the area between the neck and the main body. The seal needs to be tight but slick to allow the neck to pivot freely against the main body. The smooth plastic on the soft foam maintains a good seal while still allowing movement.
STEP 3
Q: What are the identifying marks on the back of the soleplate for?
Q: What function do the channels at the front serve? / A: All companies must legally label parts with their name, along with the material classification and recycling code. This helps ensure a seamless transition at the end of the machine’s cycle of life. The bottom code is used to identify the manufacturing tool and the Dyson part number.
A: The main function of the soleplate is to maintain a seal on the floor to trap airflow. But allowances need to be made to allow larger debris into the tool. The channels provide a path for larger debris, whilst maintaining a good seal on the floor.
STEP 4
Q: Why is the main housing transparent?
Q: What is the purpose of the lint filter?
Q: Why did Dyson engineers design the guide vanes to turn the air? / A: The top main housing is clear to allow the user to see the gears. The gear rotation is clearly visible so the user can see the tool working. In normal turbine heads, the housing is clear to allow the user to spot any clogs or tangles – but this tool is tangle free!
A: This is a protective piece. The turbine is very precise and relies on unobstructed airflow. Any unwanted dust or debris can easily clog the turbine and prevent the tool from working.
A: Turning the air causes it to hit the side of the turbine face straight on and maximizes the power extracted from the airflow.