Slowly expanding gasket and method for use thereof

A gasket and/or sealing material is used in sealing a cellular telephone. A method for assembling a gasket and/or sealing material for sealing a cellular phone is also provided.

TECHNICAL FIELD
 The invention relates to a gasket and/or sealing material for use in
 sealing a cellular phone. The invention also relates to a method for
 assembling a gasket and/or a sealing material for sealing a cellular
 phone.
 BACKGROUND
 Various types of gaskets are needed in cellular phones. Their purpose is to
 create acoustic sealing, to prevent dust from penetrating into the phone,
 to provide EMI-shielding etc.
 The currently employed gaskets of the above mentioned type are made of soft
 elastic foam plastic and sealing is obtained when the gasket is
 compressed. To achieve an efficient sealing the compression of the gasket
 must be as large as possible, i.e. the uncompressed gasket must have a
 considerable thickness in order to obtain a tight sealing in its
 compressed state. However, it may be very difficult to assemble a phone
 with thick gaskets since the uncompressed gaskets interfere with the
 mating components and therefore require excessive force to be applied.
 A gasket intended for use as a fluid seal in a plate and frame apparatus,
 such as a heat exchanger, is disclosed in U.S. Pat. No. 5,486,010. The
 gasket material comprises a core of elongated and preferably expanded
 polytetrafluoroethylene (PTFE) contained within a tight wrap of high
 strength film. The gasket is pre-compressed to aid installation by forming
 the gasket under pressure to the desired shape. However, the densification
 should not be so great that further compression and fitting of the gasket
 cannot occur during actual installation. Sealing is only obtained at the
 final compression when the plates are stacked in series and mounted
 between frames which then are tightened by means of compression bolts.
 SUMMARY
 The object of the present invention is to achieve an improved gasket and/or
 sealing material for use in sealing a cellular phone providing a solution
 to the above mentioned problems and drawbacks when assembling the phone.
 The object of the present invention is obtained by a gasket and/or sealing
 material.
 Another object of the present invention is to provide a method for
 assembling a gasket and/or sealing material for sealing a cellular phone.
 By manufacturing the gasket from slowly expanding cellular plastic, e.g.,
 polyurethane foam (PUR), expanded polyethylene or polyvinylchloride, the
 gasket may be pre-compressed before assembling the phone. In this way the
 installation of the gasket material can be greatly enhanced by
 pre-compressing the gasket prior to installation. Since the gasket has the
 benefit of staying in its compressed state for several seconds, the phone
 can easily be assembled with the gasket of the invention still in its
 compressed, state. Not until after the phone has been assembled, the
 gasket expands and seals against a mating component. Preferably the gasket
 according to the invention is pre-compressed to more than approximately
 50% of its original thickness.

DETAILED DESCRIPTION
 In FIG. 1 an embodiment of the present invention is shown, wherein an
 elastically deformable gasket and/or a sealing material 10 is installed in
 a cellular phone in order to e g provide acoustic sealing, prevent dust
 from penetrating into the phone etc. The gasket 10 of the invention is not
 intended to withstand large pressures and therefore does not provide a
 seal against e g fluids.
 A suitable material for the gasket and/or sealing material 10 is a soft,
 deformable, elastic, cellular plastic. One such plastic material is for
 instance polyurethane foam (PUR) which is used today, e g in ear plugs,
 and has the property of especially slow expansion. Other possible
 materials for the gasket 10 of the invention are expanded polyethylene,
 expanded polyvinylchloride or foamed latex.
 The gasket 10 of the invention is mounted in its uncompressed state in a
 component 11 of a cellular phone. In order to facilitate the assembly of a
 mating component 12, i.e. a front cover, to the cellular phone component
 11, in FIG. 2, the gasket 10 is compressed before assembly. Preferably,
 the gasket 10 is pre-compressed to more than approximately 50% of its
 initial thickness.
 In FIG. 3 is shown how the mating component 12 easily may be assembled
 while the gasket 10 stays in its compressed state. Due to the slow
 expansion of the gasket according to the invention, assembly of cellular
 phones may be achieved without requirement of undue torque or force of the
 mating components 11 and 12, respectively.
 In FIG. 4 the recovered gasket 10 can be seen in its final state where it
 seals against the surface of the mating component 12. By installing the
 gasket and/or sealing material by the method of the invention, production
 of phones can be enhanced as well as accelerated, and at the same time
 excellent sealing can be achieved.
 The present invention has been described above with reference to a
 preferred embodiment. It is, however, to be understood that the present
 invention shall only be limited by the scope of the appended patent
 claims.