Krea Limb

What it does

Krea Limb is a prosthetic arm for people with upper limb differences. The design is an end to end solution for both cosmetic and functional purposes. The socket- the part that grips on to the remaining limb of the user is custom designed for each person.

Your inspiration

While working with people with upper limb differences, we found out a gap in the current available prosthetic arms on the market. Prosthetic arm in the Indian arms are mainly divided into two categories: cosmetic and functional and if a user requires the use of both, they would need buy one of each and carry them if they need to be used in the same space. Our solution to this problem was to combine the two: having one socket with end attachments that serve different purposes. The way to use it is to swap any attachments that need to be used and easily attach it to the socket as per the user's requirement.

How it works

The socket is custom made for each person. It is adjustable with loops of string going around the socket and being able to tighten/ loosen the socket by rotating the dial clockwise/ counter-clockwise. A metal part at the end is used to attach the socket with the end attachment device via a moving metal plate. There are multiple attachments available for the user for multiple purposes: a cosmetic hand attachment for everyday use, a bike riding assistance device and an eating assist device. All of them are reversibly compatible with the socket system. The cosmetic glove is a human hand like attachment with the skin color custom matched to the user's hand. The bike ride assist has a spring mechanism to attach it to any bi-cycle handle bar and use it for riding.

Design process

We first started off with the design of the socket- it is traditionally made with casting POP on the user's stump and making a reverse mold- and then making a rigid socket with a PU sheet. We tried a different approach- by making individual struts and putting it together by cotton tape and tightening it with Velcro. After making multiple variations of the design, we arrived at a design which includes a custom made design for each user (after 3d scanning the user's stump) and putting loops of string through the whole socket and tightening the socket with a dial. Next were the attachments for the prosthetic hand end. The cosmetic hand attachment is custom matched to the user's skin color. It has a metal ring at the end that enables it's attachment to the socket system. The bi-cycle riding assistive device has a spring mechanism to hold on to the handle bar securely and use it to maneuver the bi-cycle. The design process included making various prototypes of the said attachments and testing them with the user and introducing changes hereinafter. For example, when the initial bike-riding assistive device proved incapable of providing efficient friction, we introduced a layer of silicon pad to improve the gripping experience for the user.

How it is different

Usually when faced with the prospect of using both a cosmetic and functional prosthetic hands, a person has to buy two different products with two different sockets - making it difficult to use both simultaneously- one has to carry the heavy prosthesis with them everywhere. Our solution combines the two products seamlessly- with a socket that is compatible with different end effectors, one can change the attachment as per their need and still use the product- without having to take off the socket. This directly reduces the bulky weight they would have to carry around otherwise in the form of another prosthetic arm. With the variety of attachments we are planning to design and roll-out- users will get their choice from a variety of different activities they would like to perform. This also helps in service and repair- if one attachment needs service- it is only that which would need repair and continue using the rest of the product as required.

Future plans

Deployment for the Krea Limb kit started in the second quarter of this year. We have received paid orders from 15 users so far and deployed to three users till date. We are continuing with feedback loop cycles in order to improve our product. Our data for the next set of attachments will be derived from the 25 users that we will deploy the Krea kit to this quarter. We are also working on streamlining the design process and reducing the manufacturing costs. Our aim is to make the product easy to service by designing it in a modular form ensuring that the components are easy to replace.

Awards

We received the Path Breakers' Award from the Save Shakthi Foundation at Chennai, India