Apple wants to make iOS devices with tougher composite fiber reinforced shells

Despite the situation with the bankrupt GT Advanced regarding the use of sapphire material, Apple hasn’t given up on building tougher, more durable iOS devices. The company has filed for a patent (number 20150327641) for “composite fiber reinforcement for stiffening shells.”

According to Apple’s patent, a device case can be reinforced by a reinforcing member made up of composite extrusions embedded within a top edge portion of the stiffening shell. The device shell can be utilized to define and maintain an overall shape of the device case. 

Apple says that composite fibers suitable for use in these embodiments can have high tensile strength and high tensile modulus. The device case can include a single length of embedded twisted composite fibers that extend continuously around the top edge or alternatively can include a number of discrete segments that reinforce particularly fragile portion of the top edge.

Apple says that, currently, materials such as polyurethane and leather can be wrapped around a stiffening shell to provide a stable shape and/or rigidity to a device case. The stiffening shell can be utilized to reinforce various portions of the device case. Unfortunately, in some cases the stiffening shell may not be robust enough to reinforce particularly fragile portions of the device case. For example, openings in the device case can be positioned particularly close to an edge of the casing. 

In such a configuration, a portion of the case defining the opening and bordering the edge can be particularly thin, creating what can sometimes be referred to as a thin web condition, thereby leaving the opening susceptible to damage or even breakage. Apple says that just thickening the stiffening layer enough to achieve a robust opening can leave the device case thicker and/or taller than desired. What’s more, moving the opening away from the edge can be unpractical as the position proximate the edge may be necessary to facilitate access to a portion of a device such as a user interface element along the lines of a button or switch, the company adds.

Not surprisingly, Apple’s goal is to make iOS devices that are tougher, but not thicker.