Get a Grip Project

Inspiration

For this project, I chose to explore how to better redesign bus strap handles. After riding the city buses the past few years, I think the straps could be a little easier to hang onto, especially on a crowded bus at the end of a long day.

Current strap design on most Pittsburgh buses is generally just a piece of standard nylon strap, which can cut into users hands and slip off easily. I sought to incorporate an added plastic or rubber element to the strap, taking inspiration from duffel bag handles as well as other bus strap designs to mold a grip that fits for many hands. 

Existing bus strap design (left), ergonomic duffel bag handle design (right)

Initial Sketches

My initial sketches explored the use of a rubber/plastic casing that would snap onto a bus handle, using ridges and a natural flexible material to be flexible for users holding on the bus handle. The ridges would offer greater grip but not be spaced apart enough to where it would pinch the user's hands when the handle flexes when weight is put on it (something I've personally experienced from backpack or suitcase handles). 

After critique on the first set of sketches on the left, I was encouraged to explore models with an open design on the bottom. This way, users could place the handle on any strap of their choosing and take it with them when they travel (putting the onus on the user instead of expecting Port Authority to change all of their handles). As an added benefit, users could also take this gripper and flip it upside down to carry different bags at once (like several grocery bags or other shopping bags). Another item of feedback that came up was how the grip adjusts to different hand sizes -- for instance, if a user has big hands, does the grip pinch them on the ends?

Based on this feedback, I came up with the second sketch model (right image) with an open design. This model also has extensions on each end which flex up to provide the user with better grip as well as protect users with larger hands from pinching their fingers on the area between the strap and end of the gripper.

Clay Model Prototype

After exploring different sketches, I decided to put one design to the test, sketching it out in greater detail and then building a clay model. 

Sketching

My first sketch emphasizes the use of diamond hills and valleys as a way to direct the user for where to put their fingers. I was inspired by football lacing that implicitly teaches users to align their fingers a certain way when throwing a football. I also was partially inspired by Toblerone chocolate bars and their use of "mountains" to separate the different portions of chocolate.  I used diamond designs because they provide more flexibility for users to shift their fingers left-to-right compared to just straight raised bars. 

Clay Model

My first clay prototype used clay beads (left) to represent the joints the gripper would bend against, providing flexibility in the motion of the gripper. I molded a clay layer on top of these beads and from here added raised diamonds (right) to create the hills for better grip. Since I didn't have a bus strap on hand, for prototyping purposes I created a temporary strap out of duct tape and card-stock and molded it to have the flexibility of an actual bus strap.

Feedback

After exploring this design, I realized that the diamond pattern may be a little too rough on the users hands, no matter how much I attempted to smooth the corners of the diamonds. I also wanted to play a little more with the thickness of the initial top layer, but with the current clay-only model, I was struggling to maintain structural integrity. I needed to examine other materials which could provide structure but still maintain desired flexibility. 

Final Prototype

Based on my findings from the previous model, I decided to tweak my design to something a little more ergonomic and smoother to use. 

Sketching

For this design, I decided to ditch the diamonds and instead try for a natural rolling hill approach. This version still maintains all the fun features of the previous design (hills and valleys, extensions to make it usable for all hand sizes, extended sides to sit firmly on the bus strap), but with a few added elements. 

I decided to switch from a three-diamond approach to a four-hill approach as the diamonds proved a little rough for user hands and the hills felt nicer to the touch. While the grip is meant to guide users to a hand position that they are comfortable with, the diamonds were a tad aggressive and as such the hills offer the same guidance but with a little more flexibility on the user’s part to shift their position as needed. I also added slight knurling on the extensions on the ends and in the valleys to provide better texturized grip for the users. 

Clay Model

Final model top view (left) and side view (right)

Close of up knurling pattern for grip (left) and flexed handle in action (right)

For the final model, I incorporated cardboard pieces as a flexible and strong scaffold to build the strap gripper. While the assignment called for use of a wood skeleton, since my product is flexible fabric, I felt the cardboard was more appropriate for use than wood. I used a main piece of cardboard as a strap base to model the main structure onto, and I used 2-3 layered mini-domes of cardboard to help structure the new hill design of the gripper.

Reflection

This project was an interesting way of examining product redesign from an ergonomic perspective. I enjoyed taking an everyday object and figuring out a way to make it easier to hold through something as simple as clay modeling. In retrospect, I would have picked an object that was more solid and easier to model onto as modeling onto a strap was pretty difficult given its flexibility. However, by examining strap grip design, I found that this gripper (when turned upside-down) also works extremely well for carrying things - such as heavy grocery bags or duffel bags - so this project definitely has potential future applications beyond transit.