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Shock-Absorbing Laminated Thermoplastic Elastomer/Urethane Foam Covers for a Hand Held Tablet Computer

IP.com Disclosure Number: IPCOM000105291D
Original Publication Date: 1993-Jul-01
Included in the Prior Art Database: 2005-Mar-19
Document File: 2 page(s) / 62K

Publishing Venue

IBM

Related People

Bratton, WE: AUTHOR [+2]

Abstract

To protect the electronics of a computerized tablet from a drop height of four (4) feet, a laminated dampening material was developed to use as an external cover. The covers provide not only shock protection but also aesthetics for the tablet computer.

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This is the abbreviated version, containing approximately 62% of the total text.

Shock-Absorbing Laminated Thermoplastic Elastomer/Urethane Foam Covers for a Hand Held Tablet Computer

      To protect the electronics of a computerized tablet from a drop
height of four (4) feet, a laminated dampening material was developed
to use as an external cover.  The covers provide not only shock
protection but also aesthetics for the tablet computer.

Elastomers are very good for shock and impact protection.  The
typical peak acceleration for an elastomer decreases sinusoidally
over time.

The peak acceleration for a dampening material such as urethane foam
is much lower, and the curve tends to flatten more quickly than the
elastomer.  This flattening or achievement of a near horizontal slope
is ideal for impact protection.

The problem with foams is that from an environmental and aesthetic
standpoint they do not fare well.  This led to the development of a
composite, laminated thermoplastic elastomer (TPE)/urethane foam
cover now being used on the tablet computer.

The laminated covers designed for the computer consist of a moldable
TPE laminated with a closed cell urethane foam.  The selected
urethane foam has a cushioning efficiency curve that approaches 2.5,
1 being the most ideal.  Most polyurethane or urethane foams are well
suited for dampening, however, their cushioning efficiency curves
only reach as low as 3.5 to 4, at best.  With the small space
consideration for a tablet computer, the selected foam is the best
choice.  The TPE was chosen for it...