Browse Prior Art Database

Ruggedization System for Space-Constrained Mobile Computer Products

IP.com Disclosure Number: IPCOM000119177D
Original Publication Date: 1997-Dec-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 6 page(s) / 152K

Publishing Venue

IBM

Related People

Khanna, VD: AUTHOR [+3]

Abstract

Disclosed is a shock isolation system for Personal Computer Memory Card International Association (PCMCIA) type form factor devices and, in particular, PCMCIA hard disk drives. Such products are potentially exposed to high shock inputs (as when dropped) but due to their compact geometry have no isolation means to attenuate the impacts. This invention teaches the use of resilient material at the corners of the devices that can deform beyond the envelope of the device and, thus, achieve an "outside-of-form-factor sway space".

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Ruggedization System for Space-Constrained Mobile Computer Products

      Disclosed is a shock isolation system for Personal Computer
Memory Card International Association (PCMCIA) type form factor
devices and, in particular, PCMCIA hard disk drives.  Such products
are potentially exposed to high shock inputs (as when dropped) but
due to their compact geometry have no isolation means to attenuate
the impacts.  This invention teaches the use of resilient material at
the corners of the devices that can deform beyond the envelope of the
device and, thus, achieve an "outside-of-form-factor sway space".

      Conventional computer peripheral shock testing has usually been
limited to inputs along principal axes and the isolation efforts and
inventions resulting thereof have been aimed at improving face-flat
impacts.  As a result, the type of shock isolators used in
conventional Direct Access Storage Device (DASD) formats are not only
ineffective, but  also inappropriate for a PCMCIA layout.  A random
drop of a mobile computer product is most likely to impact on a
corner first.  Thus, an  isolation system that takes advantage of
this observation is more effective than a conventional shock isolator
design.  The isolator also  needs to be effective without consuming
the PCMCIA form factor envelope  that is required to package the
electronic and mechanical components.

      Fig. 1 shows the impact mechanics of a simple object with a
single linear and angular degree of freedom.  The object is of length
2L and impacts a floor with linear velocity V sub 0.  A corner,
designed with a resilient material, deforms into space outside the
static boundary  of the object during the first impact.  The first
impact converts the linear velocity-based kinetic energy of the
object partially into rotational kinetic energy.  Following the first
impact, the linear and  angular velocity components V ' and ' theta
dot have been analytically  derived for two extreme cases; one with
no energy loss and the other with  no bouncing of the corner at
impact.  In Fig. 1, it is observable that  the deformation represents
the function of a conventional sway-space, but  in this configuration
it is a free parameter and is only constrained by  design
consideration.  The impact dynamics continue to evolve until the
corner in the opposite side impacts the floor.  The corner material
is required to be r...