U.S. patent number 3,681,723 [Application Number 05/206,464] was granted by the patent office on 1972-08-01 for magnetic membrane switch.
This patent grant is currently assigned to Western Electric Company, Incorporated. Invention is credited to Frederick Martin Goll.
United States Patent |
3,681,723 |
Goll |
August 1, 1972 |
MAGNETIC MEMBRANE SWITCH
Abstract
A magnetic membrane switch includes two opposed sheets of
material which are magnetized in such a way that they repel each
other. At least one of these sheets is flexible. The sheets are
supported so that there is a predetermined spacing between them.
The opposed faces of the sheets are provided with a thin metallic
pattern. Portions of the metallic pattern can be made to contact
one another by pressing on localized sections of the flexible
sheet. The resulting contact achieves a switching operation. By
placing an alpha-numeric code on one of the sheets, the switch can
be utilized as a keyboard.
Inventors: |
Goll; Frederick Martin
(Treichlers, PA) |
Assignee: |
Western Electric Company,
Incorporated (New York, NY)
|
Family
ID: |
22766512 |
Appl.
No.: |
05/206,464 |
Filed: |
December 9, 1971 |
Current U.S.
Class: |
335/207; 200/517;
200/86R; 341/34 |
Current CPC
Class: |
H01H
13/702 (20130101); H01H 13/785 (20130101); H01H
36/0073 (20130101); H01H 2209/002 (20130101); H01H
2229/012 (20130101); H01H 2209/03 (20130101); H01H
2229/044 (20130101); H01H 2217/018 (20130101); H01H
2209/074 (20130101); H01H 2201/03 (20130101); H01H
2209/052 (20130101); H01H 2227/018 (20130101); H01H
2221/04 (20130101); H01H 2227/006 (20130101); H01H
13/703 (20130101) |
Current International
Class: |
H01H
13/70 (20060101); H01H 13/702 (20060101); H01H
36/00 (20060101); H01h 001/54 (); H01h
003/12 () |
Field of
Search: |
;200/86R,159B
;335/205,206,207 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
"Pin Board," IBM Technical Disclosure Bulletin, Vol. 8, No. 1, June
1965, page 23..
|
Primary Examiner: Envall, Jr.; Roy N.
Claims
1. A switch which comprises:
a flexible sheet of dielectric material having magnetized
portions;
another sheet of dielectric material opposite the first sheet
having magnetized portions, the magnetization being such that the
magnetized portions of the opposed sheets repel one another;
means for holding the sheets in a desired spaced relationship such
that exerting a localized force on the flexible sheet results in a
portion of the flexible sheet contacting an opposed portion of the
other sheet; and
a conductive switching pattern formed on the surfaces of each sheet
which face one another, whereby upon the exertion of the localized
force a particular portion of one of the sheets contacts the
opposed portion to
2. The switch of claim 1 wherein the sheets are formed of a
polymeric
3. The switch of claim 2 wherein the magnetic sheets are provided
with integral projections extending from their facing surfaces and
underlying the metallic pattern, the ridges being positioned to
provide for positive
4. The sWitch of claim 1 wherein one of the sheets is labeled with
an alpha-numeric code on the side opposite that bearing the
metallic pattern,
5. The switch of claim 4 wherein the portions of the sheet bearing
the
6. The switch of claim 1 wherein the thin metallic pattern is
formed of
7. The switch of claim 6 wherein the metallic pattern includes
layers of
8. The switch of claim 1 wherein the flexible sheet has a maximum
thickness of 0.100 inch and the spacing between the opposed
surfaces of the metallic
9. The switch of claim 1 wherein an insulating sheet is interposed
between the magnetized dielectric sheets, the insulating sheet
having openings therein at positions which correspond to desired
contact points of the
10. A switch which comprises:
first and second opposed flexible sheets of dielectric material
having various portions thereof permanently magnetized, such that
the opposed sheets repel one another;
means to hold the magnetized sheets in a desired spaced
relationship such that a portion of the first sheet can be made to
contact an opposed portion of the second sheet by exerting a
localized force on the first sheet; and
a thin metallic switching pattern formed on the surfaces of each
sheet which face one another, whereby when a particular portion of
one of the sheets is contacted with the opposed portion a desired
switching
11. A method of connecting conductors, which comprises:
magnetizing at least one magnetic portion of a first sheet of
dielectric material, said portion being connected to at least one
conductor;
magnetizing at least one magnetic portion of a second sheet of
dielectric material, said portion being connected to at least one
other conductor, at least one of the sheets being flexible;
supporting said sheets in a spaced relationship so that said
magnetic portions are opposite to, spaced from, and repel each
other; and
exerting a localized force on at least one sheet that is flexible
to engage the conductors and thereby interconnect the conductors
connected thereto.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to membrane switches and their use as
alpha-numeric keyboards.
2. Description of the Prior Art
There is an increasing need in the telecommunications industry for
keyboard instruments of a simple and inexpensive design. A greater
and greater amount of information is being transmitted by
keyboard-type inputs. Presently utilized keyboards typically
involve individual mechanical elements for producing an electric
contact associated with each alpha-numeric symbol.
Various attempts have been made to produce a so called
membrane-type of keyboard in which two flexible members are held in
spaced relation. Electrical contact associated with a particular
alpha-numeric symbol is produced when a localized region of one of
the separated membranes is made to contact the opposed membrane. In
a membrane-type keyboard, it is of course, necessary to provide
some resiliency in the structure so that the depressed localized
regions will return to a non-contact position when the associated
alpha-numeric symbol is released. Previous attempts at providing
the desired resiliency within membrane-type keyboards have not been
entirely successful.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide a novel and
practical switch which will function in a membrane-type
keyboard.
Another object of this invention is the provision of new and useful
methods of interconnecting conductors.
This and other objectives are achieved by providing a switch which
includes first and second sheets of dielectric material which are
magnetized so that the opposed sheets repel one another. As least
one of the sheets is flexible. The magnetized sheets are held in a
desired spacing such that a portion of the first sheet can be made
to contact an opposed portion of the second sheet by exerting a
localized force on the flexible sheet. Each of the sheets are
provided with a thin metallic switching pattern arranged so that
when a particular portion of one of the sheets is contacted with
the opposed portion, a desired switching arrangement is
achieved.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects and features of the present invention will be more
readily understood from the following detailed description of
specific embodiments thereof, when read in conjunction with the
appended drawings in which:
FIG. 1 is a perspective view of various elements magnetic-membrane
keyboard;
FIG. 2 is a perspective view of various elements of the keyboard of
FIG. 1 with the elements separated from one another for purposes of
clarity;
FIG. 3 is a sectional view through the keyboard of FIG. 1 showing
one alpha-numeric symbol depressed so that electrical contact
associated with that symbol is produced and with various layers of
the keyboard having an exaggerated thickness for purpose of
clarity; and
FIG. 4 is a schematic representation of a useful magnetic profile
for the magnetic elements of the keyboard of FIG. 1.
DETAILED DESCRIPTION
A composite keyboard, designated generally by the numeral 20, which
embodies the inventive switching arrangement is illustrated in FIG.
1. FIG. 2 shows various elements of the keyboard 20 in an expanded
arrangement and with a supporting frame 21 removed. It should be
noted that the keyboard 20 is shown with only four alpha-numeric
symbols for purposes of simplicity. The inventive principles
embodied in the illustrative example can be applied to keyboards
having in unlimited number of alpha-numeric symbols.
Referring now to FIG. 2, it can be seen that an upper sheet,
designated generally by the numeral 22, of flexible magnetic
material overlies a lower sheet 24 of magnetic of material. The
lower sheet 24 may be either flexible or rigid. If application of
the keyboard 20 to a curved surface is desired, flexibility within
the sheet 24 may be useful. However, if the keyboard is to be used
on a flat surface, the sheet 24 may be rigid.
One example of a material which is useful for making the sheets 22
and 24 is a polymeric sheet available from B. F. Goodrich
Industrial Products Company, Akron, Ohio which is sold under the
product designation "Koroseal."This material has ferrite particles
embedded in a poly-vinyl chloride binder.
Each of the sheets 22 and 24 is provided with metallic elements 26
thereon. The metallic elements 26 must be thin and flexible when
they are applied to flexible sheets, such as the sheet 22. One
particularly advantageous way of applying the metallic elements to
the sheets 22 and 24 is by a process of vapor deposition such as
evaporation, sputtering or the like.
One suitable application of the metallic elements 26 to the sheets
22 and 24 was accomplished by evaporating 1,000 angstroms of
titanium and 50,000 anstroms of gold through metallic stainless
steel masks onto the sheets 22 and 24. The metallic elements 26
were deposited on the flexible sheet 22 having a thickness of 0.050
inch. The sheet 22 was supported 0.001 inch from the sheet 24 in an
operable switching arrangement.
In cases where a mechanically stronger conductor system is desired,
it may be advantageous to employ a metallic element formed of
titanium-palladium-copper-gold.
It can be seen in FIG. 2 that the metallic elements 26 are formed
with contact portions 28 and lead portions 30. The contact portions
are arranged to provide perpendicular intersections of the metallic
material when an alpha-numeric symbol is depressed. The lead
portions 30 of each sheet are arranged to emerge from the sheet on
a substantially parallel path so that connections to the sheets 22
and 24 can be readily provided.
An insulating sheet 34 is interposed between the magnetic sheets 22
and 24. The insulating sheet 34 is provided with openings 36 that
correspond to the position of the contact portions 28.
Referring now to FIG. 3, which is a cross-sectional view of the
keyboard 20, it can be seen that when a portion of the sheet 22
with one of the symbols is depressed, electrical contact occurs
between the contact portions 28 which underlie that symbol. The
lead portions 30 associated with the particular engaged contact
portions 28 are connected to the apparatus which is to be
controlled by the keyboard through conventional connection means,
such as connection terminals 40 and other connecting elements (not
shown).
As illustrated in FIGS. 1-3, the upper sheet 22 is not a simple
flat sheet even though a simple flat member is a perfectly
acceptable and workable configuration for the upper sheet. The
upper sheet illustrated in the drawings is provided with raised
portions 42 in the area of the alpha-numeric symbols. A raised
portion on the outside of the keyboard, of course, facilitates ease
of manual contact with the desired area of the keyboard. Raised
portions 44 on the contact side of the sheet 22 provide for more
positive electrical connection between the contact portions 28.
Since the sheet 22 is a polymeric substance, the raised portions 42
and 44 can easily be molded into the sheet during the fabrication
thereof.
An alternate to the extruded or molded projection might include
separate buttons supported above the upper sheet in a loosely
fitting frame (not shown).
FIG. 4 shows one workable scheme by which the sheets 22 and 24 can
be magnetized so that they will continuously repel one another.
Obviously many other patterns for magnetization can be utilized to
accomplish the desired object of having the alpha-numeric symbols
repulsively held above the lower sheet 24.
Although certain embodiments of the invention have been shown in
the drawings and described in the specification, it is to be
understood that the invention is not limited thereto, is capable of
modification and can be arranged without departing from the spirit
and scope of the invention.
* * * * *