D4E1 Redesign MetroJuggle

We, (Daniyal Mustafa, Taro Bamps and Chris Schramm), were tasked to redesign the Metro juggle. The original tool was made for Woesh, to be used by people with and without disabilities. It trains motor skills, lateralisation of hand and eye coordination as well as improves social contact. An open design (materials that can be found everywhere) is used. The construction is ergonomic so that users can function as optimally as possible. Moreover, the construction is modular, e.g. the amount of tubes can be adjusted. Our redesign focuses on easier transportation and convenience, with the main highlights being compactable and better adjustability.

#HOWESTIPO, #WOESH, #D4E1, #CIRCUS

Required tools for construction:

• CNC machine with a minimum bed dimension of 1500x1000mm and with minimum max height of 100mm.
• Saw (manual or machine)
• Sandpaper / files (manual or machine) (for CNC post processing)
• Knife (for cutting foam)
• Drill (handheld)
• Screwdriver (bit type dependant on screws sourced)
• 2mm drill bit (universal)
• Pen (to mark dimensions)
• Hammer
• chisel (optional see step 3)

PVC Tubes:

2 x '2 m' with a diameter of 50 mm (wall thickness of 1,8 mm)

1 x '1 m' with a diameter of 40 mm

Cross joint:

50mm PVC Cross joint (see Image)

Weights:

2 x '2 kg' (Inner diameter 50 mm, Outer diameter 165 mm, 25 mm height)

Nails:

24 x Nails of 1,5 x 30 mm

Screws:

80 x '4x12 mm' countersunk screws

4 x '2.5x25 mm' countersunk screws

12 x '2.5x12 mm' countersunk screws

Bolts & Nuts:

4 x countersunk M5 x 25 mm (may vary depending on handle)

4 x 'M5 x 20 mm' wide washers

Wood:

Multiplex (plywood) sheet 12 mm thick (1500 mm x 1000 mm)

Foam:

PS foam sheet (650 mm L x 400 mm W x 100 mm H)

Handle:

solid piece handle, heavy duty, with four bolt holes and rounded grip (preferably, for comfort)

Example:

Glue:

wood glue

super/ contact glue

Hinges:

6 x '64 mm x 52 mm x 2 mm' (total flat dimensions)

Assembly-Squares:

6 x '40 mm x 40 mm x 30 mm x 2 mm'

Latches:

2 x Small door latches (bigger side: 30 mm x 50 mm) (see image for details)

2 x Spring Loaded latches (74mm L)

Use any 3D printer which is available ( we used a printer from bambu labs)

Preferred infill is 20% or more

Layer height 0,1 mm or lower (for operational smoothness)

wall thickness 1,2 mm

works with PLA, but PETG or stronger is recommended due to creep.

In total you will need to print:

4x Screw end cap

2x Weight screw (both halves)

2x Weight nut

Take the two tubes of 2 m (50 mm diameter) and cut from them:

4 segments of 60 cm

2 segments of 26,5 cm

6 segments of 12 cm

Take the 40 mm diameter pipe and cut it to 63,2 cm

Try to be as accurate as possible. If the pipe ends are not cut to a near exact perpendicular, trim them using a belt or disk sander. This is critical to the fit when the parts are stored in the foam casing.

During the setup of the sheet on your 3-axis CNC surface, use a buffer sheet (usually MDF) as the end mill will cut through the full 12 mm mutiplex sheet thickness. Crucially, ensure that the sheet is fully fixed in place and as flat as possible. During the cutting process, some tool head changes will take place. With the equipment of our facility these are our tools used:

5 mm end mill (compatible with wood use)

8 mm end mill (compatible with wood use)

(see Image for instructions on depth and depth zones)

For the setup, use used a number of 8mm wide tabs with a height of 6mm to secure the parts. The friction clips in particular are vulnerable to jump out during the cutting process.

After the milling is done, use a chisel or saw to remove the parts.

The foam is much the same as the wood with the exception of no buffer sheet used and a different mill. We don't need to use a buffer sheet as the CNC needs to be programmed with a 1.5 mm offset from the bottom. This is easy to cut out during post processing.

The mill recommended for the foam is a 20 mm diameter end mill with a 120 mm cut depth (compatible with semi hard foam).

Take following pipes from Step2:

1 segment of 26,5x5 cm

3 segments of 12x5 cm

Connect those to the cross joint to achieve a cross shape (look at pictures for clarification)

Afterwards screw the vertical segments with the cross joint (4 of 2.5Mx12mm)

The horizontal segments will be glued to the cross joint

Complete this assembly twice.

Put the two halves together into the pipe (alignment trick). Insert the screw cap and install two (2.5Mx12 mm) screws to secure the cap (predrilling might be required with a 2mm bit).

Then remove the screw system from the pipe and press in the other cap on the other side.

Re-insert the screw into the lower vertical pipe segment and drill two 2mm holes. Add a countersink to these holes and then secure it with two (2.5Mx25 mm) screws.

Using glue and 4 nails, Attach the 4 friction clips in their designated spots (pre-milled). Make sure that the clips are stacked in pairs and aligned well with minimal overlap.

Take all CNC milled wooden sheets and align them. (according to the pictures)

Begin with the front, glue and nail it to the base plate. Repeat for the back side.

After that you install the sides on top of the base.

The red dots in the picture help find the spots to nail.

Refer to the images for placement locations:

Using the images below, align and screw in the assembly squares to strengthen the box. For those mounted in the corners, screw them halfway up the height of the side panels. 24 4x12 mm countersunk screws will be used.

Using the images below and the 3D model for reference, align and screw in the hinges.

For the back, align the hinges closer to the end of the grooves, and from the side, it should look like the centre of the hinge pin is in line with the top face of the back plate. Then the big top plate is mounted on the hinges, ensure that it is centred and parallel with the back plate, while in extreme extension(open position).

For the front, the hinges are to be mounted with an opposite flex(see image). First, on the smaller top plate, about 10 cm from the outside edges, then mount the assembly on the front wall. As a result, on the front wall, the hinge is visible on the outside, and on the top plate, the hinge is visible on the inside of the box.

For the side panels, the hinges are mounted in a straightforward manner, ensuring the top edges of the panels and the big top plate are in line.

36 4x12 mm countersunk screws will be used.

Place the sliding latches horizontally on right side wall, while aligning the top edge and the left edge of the latch to the top edge and left edge of the protruding part (see image). Repeat for the other side.

Now for the spring loaded latches, which are used to close the box, install the bigger part (interactive part) inside the protruding shape on the smaller top plate (see image). Install the counterpart (hook part) on the bigger panel while ensuring appropriate tension on the latches while closed.

Tip: to ensure the correct tension, assemble the latch with both its parts without screwing the hook to the panel and push the hook part away from the bigger part in neutral position, then mark the holes for the hook part.

The handle is attached to the front panel. The alignment of the handle could vary with different handles, so do the appropriate calculations and align the handle at the centre of the front panel (including the top plate). After finding the correct position, the handle is simply attached with countersunk M5 x 25 mm bolts (size varies depending on handle), with the 20 mm wide washers.

* It is recommended to get a handle with rounded grip for comfortable use, however, the handle that we have used does not have a rounded grip, therefore, we applied some wrapping around it. This optional step can be done in case of unavailability of a rounded handle. *

Refer to the images for reference:

Make sure that the weight cut-outs are positioned towards the bottom of the box. The bottom of the box is connected to the bigger opening flap. The tolerances are press fit so you must put some force into inserting the foam into the box. This is for safety reasons.

You might also need a knife or chisel to cut away some of the foam that would collide with the rear assembly squares. An example is shown in the images.

Finally take all the parts and place them into the foam casing as you can see in the picture, and voila!

Estimated cost breakdown for 1 copy:

2 cross joints -> 2* 4,98 € = 9.96€

6 hinges -> 6* 2,30€ = 13.80€

24 x Nails of 1,5 x 30 mm; 80 x '4x12 mm' countersunk screws; 4 x '2.5x25 mm' countersunk screws ; 12 x '2.5x12 mm' countersunk screws --> roundabout 20€

6 Assembly squares -> 6 * 0.76€ = 4,56€

2 spring loaded latches -> 2* 1,49€ = 2,98€

2 latches -> 2*4,80€ = 9,60€

1 handle = 4.15€

4 pipes 2m diameter 50mm -> 4*1,60€ = 6,40€

1 pipe 1m diameter 40mm = 1.25€

Multiplex plate 12mm 1500x1200mm = 30€

Foam block 10mm 650x400 = 10€

3d printing = 20€ (howest prices) (filament prices 6-10€)

cnc milling= 30€ (howest prices)

wood glue + contact glue= 6€

Total: €168.7