Excerpts from the book "How Design Changed America" by Henry Keck
Our first thought was that the user should have something soft and not cold to the touch. It should also be attractive and streamlined. Streamlined seems absurd at first thought but we were thinking that in use suitcases are stacked together in a rough and careless manner. Thus a handle that was not blunt at each end would slide over the adjacent obstacle and survive abuse better.
To this end we designed a handle using a technique of manufacture that was new at the time, double injection molding. This concept widely used today for toothbrushes and other consumer products permits the use of different plastics together to meet optimum depth of color and other requirements.
Our concept was this: Why not have a handle with a very strong upper bridge and a soft underbelly. We thus specified a hard, tough top frame into which we placed a softer material in the bottom grip area.
To do this, the double injection molding principle came into play. First the upper hard bridge part was molded as a separate part. Then this part is inserted into another mold and the softer plastic material is injected into it. Careful detailing of the hard upper bridge includes holes through which the second material in its liquid state could flow. This assures a strong attachment between the two materials of the handle.
We thus had a sturdy handle with a soft grip for comfortable holding.