Normativa de la Economía Popular y Solidaria

In this concept direction, five simple concepts originated that were all easy to develop had no big uncertainties to them whilst remaining transparent, low cost, slim and low weight. Stated on the next page is an overview of these concepts accompanied by a brief explanation. Subsequently the final concept is presented. All of the concepts offer the fol- lowing basic functionality:

• Usable as cutting board

• Slim and thin, around 35 mm thick at most

• Usable as a serving tray

• Cool area’s that enable the user to move or carry the tray when hot.

• Adjustable temperature

• Heating indicator

• Overheat protection

• Power cord of 1,6 m

• Maximum weight of 3 Kg

• Automatic fault and glass breakage detection to ensure safe operation.

• A surface area of about 2016 cm2

• Removable power cord

• Target price R$ 175

• Maintain desired temperature automatically

• Comply with the new power plug standard (NBR 14136)

The requirements as set by INMETRO are not covered because they are not yet relevant at this stage.

This is the first concept. The heated surface can be ordered or manufactured by ABINFO and requires an electric connection on both sides. Therefore, a cable runs through a chute to connect both sides. This concept has laser cut aluminium handles bent under a slight angle for better handling. Simple tapered legs are screwed to the handles and this subassembly is glued to the glass surface. The interface and power supply can be inte- In this chapter the first three concept directions mentioned in chapter 7 are elaborated on for these are the most feasible ones.

grated in the casing of the tray itself; however, this would make the casing for more complex and bulky. Incorporating everything in a simple box integrated in the power cord is much easier to realize, saves space and keeps the electronics away from liquids, which is safer and more hygienic. Also with respect to the other concepts, this solution is the best option concerning this concept direction in general. It is a sleek and minimal tray but it looks rather standard i.e. not innovative and is not very sturdy.

The concept depicted above encloses the glass surface in a sturdy casing with integrated legs. The frame is made of extruded aluminium profile on the short side along with laser cut parts on the long side. The handles are made of wood and pull the frame together. Although, this is a very interesting concept it has a certain retro feel to it, which does not resonate with the intended look. However, this certainly has been the basis for the even- tual concept, as will become clear later on.

This concept revolves around an elegant and minimalistic frame but for the initial model this is just too difficult to manufacture. Also, this concept is likely to be quite flimsy. One advantage of this concept is the possibility of having the temperature sensor in the middle but this isn’t really necessary. One could keep it simple i.e. easy to manufacture, as can be seen in the concept on the left, but then it more or less reassembles the first concept again which already has proven not to be optimal.

Figure 31: Concept No ₂

The concept stated above truly emphasizes the sleek and innovative glass heating surface but it just isn’t very practical. The raised handles are inconvenient since they don’t allow for plates, etc. to extend outside the heated surface. In addition, the handles are likely to get in the way when the tray is used as a cutting board. Lastly, for this concept to come into its own, the finish i.e. details are really important and this will be very difficult to real- ize with the available means. From all the former concepts, one final concept emerged which can be seen below:

Figure 33: Concept No ₄

Although the casing might look complex, it actually consists of only four types of laser cut slices of wood and two laser cut stripes of aluminium glued together. Subsequently this casing is painted glossy black. This results in a smooth, functional and ergonomic frame that incorporates all necessary functions.

Figure 35: Final concept render - black plastic

The brushed aluminium combined with a black casing and glass surface give it an elegant and modern appeal that fits very well within the target group type of styling. The bimetal- lic thermo switch, thermistor and cables can easily be fitted in the casing in such a way that they are not visible. The glass surface is countersunk and sealed resulting in a flat and smooth surface that is easy to clean. The surface is 56 cm long and 36 cm wide. The overall tray is compact, 4 cm high, can very well double as a cutting board and is suit- able as a serving tray. Although the laser cut casing allows for an integrated interface and power supply, it is still better to put these in a separate box incorporated in the power cord since integrating these things would impose a higher risk of shock hazard and make the overall product a lot more complex. The temperature indicator will be a simple ther- mo sticker applied on the glass surface to further reduce complexity. The control box has the same style as the tray and is also made by gluing layers of wood and aluminium to- gether. The power supply will be taken from a standard adapter, customized where nec- essary and integrated in the control box. Ideally, this adapter can account for both 110 V as well as 240 V. The trays will be tested in varying user environments. Also the technical functionality will be tested including aspects like:

• Maximum heat-up time of 5 minutes

• Maximum cool down time of 13 minutes

• Temperature range between 64°C and 113°C

• The tray must be resistant to thermal shocks

• The tray may not impose an electric shock hazard

• The tray may not hurt or burn users during reasonable use

• The tray may not damage the underlying surface

• The tray must be water resistant (not waterproof).

• Maximum power consumption of 350 W

Appearance isn’t really important for testing the technical functionality and operation but it certainly is for convincing future developers and finding users that are willing to test the tray.