A modified bin lock for VR100

Design of a better lock for the Vorwerk robot

The vacuum cleaning robot Vorwerk VR100 is among the best ones, since it offers safe navigation in the apartment and accurate cleaning of all areas, thanks to the laser mapping unit that ensures complete and uniform coverage. Other vacuum cleaning robots are available, for example Roomba, but each one has disadvantages. For example, the best one around, the Roomba models, are not able to cover uniformly the areas and, in bigger apartments, they struggle. I owned a Roomba 520 that was working perfectly on 55 square meters and I have reports of Roombas covering perfectly 80 square meters (the maximum suggested surface), but it was unable to cover reliably some parts of my 120 square meters apartment. The Vorwerk VR100 is the second best after the Roomba (second due to its price, not to the features) and I am very happy with it.

Some reviews are listed at the end of the article.

After some weeks of use, however, a design issue become apparent: the dust bin is hold in place by a notch in the plastic and it gets loose quickly. It still works well and the air passage is still sealed, but the sensor detecting its presence is triggered and the cleaning stops. Very annoying, every day coming back home I bet about the robot being at its docking station or not. 70% of the time, it was not.

I decided to develop a better locking system using Autodesk Fusion 360 (free trial now, probably free for students and amateurs in the future) and to print it using my 3D printer printrbot LCv2.

First I modeled the dust bin using a caliper to reproduce all the elements correctly, including the original green handle, then I worked on the middle plane and designed the new piece.
I decided to replace the green handle and to extend it with a support, leaving space for a slider. In the recessed position, the slider would leave enough space for the dust bin to be lifted, in the extended position the slider would engage the fixed white handle of the chassis to ensure a downward pressure on the bin. The resulting assembly can be seen in the following rendered pictures:

In the pictures, the dust bin is the big white part and the smaller white part is the handle of the chassis.

In the first design (available here in several formats) had two pins sliding inside the fixed support.

View of the new pieces engaging the chassis

The 3D printing was performed along planes perpendicular to the axis of the pins for the slider and was performed along planes perpendicular to the cylinders of the fixed holder, as seen in the following pictures:

View of the new pieces mounted on the VR100

After printing I had to make the pieces thinner, since the extrusion process tends to produce pieces about 0.2 mm larger and deeper (see here for an explanation).

The way it was printed made the piece weak, because the adherence between planes is weaker than resistance on the surface of the planes, so both pieces broke soon. Basically it was a problem of delamination of the printed layers. The slider has the pins broken, the holder had the cylinder used for the screw also torn by the screws:

I decided to simplify the design and to use a single wider pin for the slider and to skip parts of the holder: I used the original one and I added only what I needed. The results (available here) are shown in the following picture:

The new design seems to hold better.

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Author: Olaf Marzocchi

First revision: 2013-11-17.
Last revision: 2015-01-19.