Prototyping

Key Questions

Is the design too bulky to be used practically in the field?
Does the device, connected to a carabiner, remove itself from an anchor with convenient user input?
Can the device be installed on different carabiners?
What is the best mechanism for latching together a device?

After several iterations, we designed the prototype pictured to the left to answer our key questions. The prototype has the following components:

A 3D printed outer casing that rotates about a hinge and secures around the spine of the carabiner.
Foam on the inside of the casing that provides compression around the spine and holds the casing in place.
Two hex bolts and two nuts. One acts as the hinge on the outside of the spine, and the other secures the casing together on the inside of the spine.
1/16" wire rope that runs through the loop in the outer casing and attaches to the gate.
Cable clamp that creates a loop at the end of the wire rope that allows it to be secured to the gate.
Nylon string attached to the top of the carabiner that allows the user to rotate the carabiner off the anchor.

The outer casing was designed in SolidWorks and 3D printed. The other components were purchased off the shelf and assembled together.

Prototype goal: to design a snap fit mechanism that could be engaged and disengaged.
This would reduce the number of components and the size of the device.
When this design was tested, the snap-fit mechanism broke. It was determined that the approach was not suitable for this application, because it is too fragile. We were also concerned about its ability to withstand many use cycles.

Prototype goal: wrap around one side of the spine and be secured with Velcro straps. One cord was fed through the bottom and attached to the gate to open it. Another cord was fed through the bottom and attached to the top of the carabiner to rotate it off the anchor.
This prototype has several positive aspects including:
- Slim profile
- Lightweight
- Easy to assemble
- Incorporating the mechanism for opening the gate and rotating the carabiner into the same part.
When tested on an anchor, there were a few issues:
- The device did not rotate the carabiner off the anchor.
- The device did not stay securely on the spine.
Due to these concerns, we pursued our final prototype design.

Bolts used a lot of setup when considering putting device together while hanging from a wall.
Closing off gate hook decreases the load the carabiner can take.
Gate didn't open far enough some times with pulling the wire.
Users enjoyed the idea of this product and have hopes for it's success.

Several of our prototypes were not fully functional due to a lack of durability. We found that a robust method of securing the device to the carabiner is required.
A major challenge is that the carabiner gets caught in the hook and it is difficult to remove. A major focus moving forward will be on this issue.
The bolt that was used for our final prototype was too large. It is cumbersome and did not allow enough space on the inside of the spine for the gate to open. Smaller bolts should be used in future iterations.
Moving forward
- We will revisit the tradeoffs of making a standalone carabiner that is specifically design to be removed from the wall vs. making an attachment for an existing carabiners. The design of standard carabiners makes it difficult to rotate them off an anchor, so a complete redesign may be necessary.
- We will thoroughly consider the tradeoffs of strength vs. weight of the components we use. For example, we have experimented with both wire and nylon rope for opening the gate. The nylon rope is lighter, but the wire rope is less elastic so it makes it easier to open the gate.
- We will ideate and design methods to safely lower the carabiner once it has been unhooked from the anchor.
- We will rely on user interviews to help us answer these questions.

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