In total, 3 different concepts were created for the second design challenge. All were created with the aim to connect the walker to the tricycle with as least effort as possible. Discussed below are the three designs.
Design 1: Clamping mechanism
The first design involves a clamping mechanism that attaches to the basket of the tricycle. This was based on the acted-out scenarios in the earlier co-design sessions. The design is made up out of two connection points that clamp around the basket. They clamp around the basket in a c- shape. This makes sure that when the walker is attached, there is no way for it to come off when the participant is riding their bike.
The closing and camping mechansim is connected to the bottom of the walker. Next to the two clamps a separate lever is connected. This lever enables the user to release the clamps from the tricycle and take the walker off and place it on the ground.
Shown below is the clamping mechanism placed around the baskets edge. One of the c-shaped parts is powered by a gear to rotate around the bar of the tricycle. The gear is connected to the lever discussed earlier.
Depicted below is an entire overview of the concept, with the lever to release the walker placed on the most convenient part of the walker. This is chosen because it is placed on the point where the participant preferred to hold the walker when lifting it. This means that the closing mechanism will always be in an open state when the walker is carried around.
During the mid-term presentations, this concept was presented to the experts and other groups. Generally, the feedback was positive, one major critique point was the complexity of the turning / clamping mechanism.
Design 2: Ride in mechanism
The second design is based on a ride in mechanism. This means that it enables the participant to ride his walker into a holder that holds the front wheels off the ground when it is engaged. This means that the walker becomes a small trailer behind the tricycle with the back wheels still touching the ground.
The holder that is designed is mounted on the bottom part of the tricycle and can turn around an axle. This enables the walker to smoothly go through corners without scraping the back wheels through the ground.
The main usability point is that the participant does not need to lift the walker at all during the process. This might make the concept a bit more future proof compared to the other concepts, as it requires less coordination place the walker in the desired position.
A problem that this design brings is the fact that the tricycle needs to be stationary, this means that it cannot roll away during the process.
Shown below is the moment that the front wheels of the walker enter the designed mechanism. The mechanism is low enough to the ground such that the front wheels can easily ride in. Afterwards, the mechanism will be lifted in order to not touch the ground when travelling on the tricycle.
Together with design 1, this concept was pitched to the experts and other groups. The feedback was that with the back wheels still being on the ground, they might wear down very quickly due to the higher speeds when cycling. The main selling point of this product was the ability to future-proof this concept compared to the first concept.
Concept 3: Hooking concept
The final concept would also involve securing a crossbar of the walker to the basket. The walker would be pushed up small ramp and guides the walker into a slotted plate, over the edge of the basket on the tricycle. When in place, a hook-shaped plate is rotated by pressing down a lever in the basket. With this hook engaged, the walker is unable to be taken out of the slot.
The hook is disengaged by lifting the lever back up. Continuing this action will lift the walker back out of the slot thanks to the ramp-like shape on the other side of this rotating part. This gives the user a mechanical advantage when taking the walker off, and demands little coordination.
This contraption is mounted via a plate which can be bolted to the basket. This distributes the weight of the walker and attaches the product semi-permanently. This means the product does not run as big a risk of falling of or being stolen. Furthermore, it is a relatively simple mechanism which can potentially be produced sturdy enough for daily use.
Storyboard with the product: