U.S. patent number 3,886,335 [Application Number 05/327,152] was granted by the patent office on 1975-05-27 for collated cable matrix switch.
This patent grant is currently assigned to Industrial Electronics Engineers, Inc.. Invention is credited to John E. Hendricks.
United States Patent |
3,886,335 |
Hendricks |
May 27, 1975 |
Collated cable matrix switch
Abstract
In a matrix of switches disposed in rows and columns, a
plurality of first discrete conductors are deposited on the surface
of a first backing member to extend in a first direction and a
plurality of second discrete conductors are deposited on the
surface of a second backing member to extend in a second direction.
Dielectric spacing means is disposed between the first and second
backing members to maintain the first and second conductors in a
normally spaced relationship. The spacing means defines a plurality
of openings each extending between an associated pair of the first
and second conductors which define one of the switches. By pressing
the associated pair of conductors into relative engagement through
the associated opening in the spacing means, a signal on the
associated first conductor is switched to the associated second
conductor. The second conductors can extend through a pair of the
switches and can be bisected therebetween to increase the number of
discrete switches in the matrix without increasing the number of
conductors. A bar clamp provides an interface between the switches
in the matrix and the electronics associated with the controlled
operations. A method for making the matrix of switches includes the
steps of providing a spool for each of the backing members, the
conductors, and the spacing means, and guiding the conductors and
the spacing means in a spaced relationship onto the backing member.
This process can be performed at high speed with inexpensive
materials to significantly reduce the cost of manufacturing the
matrix of switches.
Inventors: |
Hendricks; John E. (Encino,
CA) |
Assignee: |
Industrial Electronics Engineers,
Inc. (Van Nuys, CA)
|
Family
ID: |
23275377 |
Appl.
No.: |
05/327,152 |
Filed: |
January 26, 1973 |
Current U.S.
Class: |
200/1R; 200/5R;
200/5A; 200/517; 341/22 |
Current CPC
Class: |
H01H
13/807 (20130101); H01H 13/702 (20130101); H01H
13/785 (20130101); H03K 17/967 (20130101); B41J
5/08 (20130101); H01H 2209/038 (20130101); H01H
2227/002 (20130101); H01H 2219/036 (20130101); H01H
2209/082 (20130101); H01H 2207/004 (20130101); H01H
2209/006 (20130101); H01H 2203/008 (20130101); H01H
2209/002 (20130101); H01H 2229/034 (20130101); H01H
2207/026 (20130101); H01H 2227/018 (20130101); H01H
2229/028 (20130101); H01H 13/703 (20130101); H01H
2209/06 (20130101); H01H 2225/022 (20130101); H01H
2211/016 (20130101); H01H 2229/022 (20130101); H01H
2207/02 (20130101); H01H 2201/03 (20130101) |
Current International
Class: |
H01H
13/70 (20060101); H01H 13/702 (20060101); H03K
17/94 (20060101); H03K 17/967 (20060101); H01h
013/70 (); G08c 009/00 () |
Field of
Search: |
;200/1R,5A,159B,86R,86A,16A,166PC,11D,11DA,166C,292 ;84/1.01,1.04
;178/17C ;235/145R ;340/365R,365,A,365E,262-270 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Scott; James R.
Attorney, Agent or Firm: Roston; Ellsworth R.
Claims
I claim:
1. A switch assembly having a plurality of switches for switching
an input signal and being adapted for use with a keyboard having a
plurality of keys each associated with one of the switches, the
keys being aligned in a plurality of rows each extending in a first
direction and a plurality of columns each extending in a second
direction transverse to the first direction, the assembly
comprising:
a first backing member having a substantially planar inner surface
and electrical insulating properties;
a plurality of first conductors disposed on the inner surface of
the first backing member and each having the input signal thereon,
the first conductors extending in the first direction and spaced in
electrically insulated relationship to one another;
a second backing member having a substantially planar inner surface
and electrical insulating properties;
a plurality of second conductors disposed on the inner surface of
the second backing member and extending in a third direction
different from the first direction and the second direction and
spaced in electrically insulated relationship to one another, at
least one particular conductor included among the second conductors
on the second backing member and extending in close proximity to an
associated pair of the first conductors on the first backing member
at a particular pair of the switches;
portions of at least the second backing member defining an aperture
which extends across and interrupts each of the particular
conductors to break the electrical continuity of the associated
particular conductor between the associated particular pair of the
switches;
insulation means disposed in juxtaposition to the inner surface of
the first backing member and the inner surface of the second
backing member for normally insulating the first conductors from
the second conductors, the insulating means defining a plurality of
openings between the associated first conductor and the associated
second conductor at each of the switches; whereby
the keys of the keyboard are actuable to move the associated second
conductor through the associated opening in the insulation means
and into electrical contact with the associated first conductor to
switch the input signal from the associated first conductor to the
associated second conductor.
2. The switch assembly recited in claim 1 further comprising:
means for introducing the input signal to one of the first
conductors; and
one of the second conductors being electrically connected to each
of the first conductors so that the input signal introduced to the
one first conductor is introduced to all of the first
conductors.
3. The switch assembly recited in claim 1 wherein the second
direction is substantially perpendicular to the first
direction.
4. The switch assembly recited in claim 3 wherein the third
direction is substantially perpendicular to the first
direction.
5. A combination for providing a plurality of switches disposed in
at least first, second, third and fourth consecutively adjacent
rows and a plurality of columns, the switches having properties for
being selectively actuated to control an operation, the combination
including:
a plurality of first conductors disposed to extend in a first
direction in electrically insulated relationship to one another and
including among the plurality of first conductors a particular
first conductor;
a plurality of second conductors disposed to extend in a second
direction different than the first direction in electrically
insulated relationship to one another and including among the
plurality of scond conductors a particular second conductor;
a spacing member having properties for electrically insulating the
first conductors from the second conductors and including
particular portions thereof defining an opening between the
particular first conductor and the particular second
conductors;
at least one actuating means defining with the particular first and
second conductors a particular one of the switches, the actuating
means having properties for being moved to force one of the
particular first and second conductors through the opening in the
spacing member and into contact with the other of the particular
first and second conductors;
a plurality of third conductors included among the second
conductors;
a plurality of fourth conductors included among the second
conductor and alternating with the third conductors;
at least a particular one of the third conductors extending through
a switch in the first row of the switches and a switch in the third
row of the switches;
at least a particular one of the fourth conductors extending
through a switch in the second row of the switches and a switch in
the fourth row of the switches; wherein
the particular third conductors are bisected between the associated
switch in the first row and the associatd switch in the third row,
and the particular fourth conductors are bisected between the
associated switch in the second row and the associated switch in
the fourth row.
6. The combination as set forth in claim 5 wherein the particular
third and fourth conductors are bisected between the second and
third rows of switches.
7. A combination for providing a plurality of switches disposed in
rows and columns, the switches having properties for being
selectively actuated to control an operation, the combination
comprising:
a plurality of first conductors having a electrically insulated
relationship to one another and disposed to extend in a first
direction through the switches in an associated row of the
switches;
a plurality of second conductors havig an electrically insulated
relationship to one another and disposed to extend in a second
direction different than the first direction to define points of
substantial intersection between the first conductors and the
second conductors, at least one of the second conductors extending
through an associcated pair of the switches in different rows of
the switches and the one second conductor being interrupted between
the associated pair of the switches to electrically insulate the
associated pair of the switches;
a spacing member having properties for normally electrically
insulating the first conductors from the second conductors, the
spacing member including particular portions which define an
opening at each of the points of substantial intersection between
the first and second conductors; and
actuating means selectively movable to force one of an associated
pair of the first and second conductors through the associated
opening in the spacing member and into contact with the other of
the associated pair of first and second conductors to provide an
electrical interconnection between the associated pair of first and
second conductors.
8. The combination recited in claim 7 wherein an input signal is
introduced to a particular one of the first conductors and a
particular one of the second conductors is connected to each of the
first conductors to provide electrical continuity between the first
conductors whereby the input signal introduced to the particular
first conductor is introduced to all of the first conductors.
9. The combination as recited in claim 7 wherein the switch columns
have a transverse relationship with respect to the second direction
and the first direction.
10. The combination as defined in claim 9 wherein the switch
columns have a transverse relationship with respect to the switch
rows and the first direction is substantially perpendicular to the
second direction.
11. The combination as recited in claim 9 wherein the switch
columns are substantially perpendicular to the switch rows and the
first direction has a transverse relationship with respect to the
second direction.
12. A combination for providing a plurality of switches disposed in
rows and columns, the switches being responsive to an input signal
and having properties for being selectively actuated to control an
operation, the combination comprising:
a plurality of first conductors having an electrically insulated
relationship to one another and disposed to extend in a first
direction through the switches in an associated row of the
switches, the input signal being introduced to a particular one of
the first conductors;
a plurality of second conductors having an electrically insulated
relationship to one another and disposed to extend in a second
direction different than the first direction to define points of
substantial intersection between the first conductors and the
second conductors, a particular one of the second conductors being
connected to each of the first conductors to provide electrical
continuity among the first conductors whereby the input signal
introduced to the particular first conductor is introduced to all
of the first conductors;
a spacing member having properties for normally electrically
insulating the first conductors from the second conductors, the
spacing member including particular portions which define an
opening at each of the points of substantial intersection between
the first and second coductors; and
a plurality of actuating means selectively movable to force one of
an associated pair of first and second conductors through the
associated opening in the spacing member and into contact with the
other of the associated pair of first and second conductors to
provide an electrical interconnection between the associated pair
of first and second conductors.
13. The combination as defined in claim 12 wherein each of the
first conductors is associated with more than one of the plurality
of switches and at least one of the second conductors is associated
with only one of the plurality of switches.
14. The combination as recited in claim 12 wherein at least one of
the first conducotrs is associated with a plurality of the switches
and particular ones of the second conductors are associated with a
pair of the switches, the particular second conductors being
electrically separated between the pair of switches so that a
different portion of each of the particular second conductors
extends through one of the switches in the pair of switches.
15. The combination as recited in claim 12 wherein the actuating
means further comprises:
a keyboard having a plurality of keys each positioned with respect
to an associated one of the plurality of switches for individually
actuating the associated switches, each of the keys having
characteristics for movement at the points of substantial
intersection between individual ones of the first and second
conductors to move the associated first conductors relative to and
into electrical contact with the associated second conductor at the
associated point of substantial intersection.
16. A combination for providing a plurality of switches disposed in
rows and columns, the switches having properties for being
selectively actuated to control an operation, the combination
comprising:
a plurality of first conductors having an electrically insulated
relationship to one another and disposed to extend in a first
direction through an associated row of the switches;
a plurality of second conductors having an electrically insulated
relationship to one another and disposed to extend in a second
direction different than the first direction, to define points of
substantial intersection between the first conductors and the
second conductors;
a spacing member having properties for normally electrically
insulating the first conductors from the second conductors, the
spacing member including particular portions which define an
opening at each of the points of substantial intersection between
the first and second conductors;
a plurality of actuating means selectively movable to force one of
an associated pair of the first and second conductors through the
associated opening in a spacing member and into contact with the
other of the associated pair of first and second conductors to
provide electrical connection between the associated pair of first
and second conductors; and
at least one series of the second conductors being associated with
a column of the switches and adjacent second conductors in each of
the series of second conductors being associated with adjacent
switches in the associated columns of the switches.
17. The combination as defined in claim 16 wherein:
the series of second conductors include a first series of second
conductors associated with a first column of the switches and a
second series of the second conductors associated with a second
column of the switches adjacent to the first column of the
switches;
a particular one of the second conductors is shared by the first
series of the second conductors and the second series of the second
conductors so that the particular conductor is associated with a
particular pair of the switches in adjacent columns of the
switches; and
the particular second conductor is bisected between the particular
pair of the switches.
18. The combination as defined in claim 16 wherein the conductors
in each of the series of conductors are different from the
conductors in the other series of conductors.
19. A switching matrix for selectively switching an input signal to
control an operation, comprising:
a plurality of first conductors disposed in spaced relationship to
one another and extending in a first direction;
a plurality of second conductors disposed in spaced relationship to
one another and extending a second direction different than the
first direction;
a plurality of points of substantial intersection each defined by
one of the first conductors substantially crossing one of the
second conductors;
a spacing member disposed between the first and second surfaces
except in proximity to each of the points of substantial
intersection of the first conductors and the second conductors;
a plurality of switches each defined by an associated one of the
first conductors and associated one of the second conductors, the
switches being operable by relatively pressing the associated
second conductor into contact with the associated first conductor
at the associated point of substantial intersection to switch the
input signal from the associated first conductor to the associated
second conductor;
the switches being aligned in a plurality of switch rows including
a first switch row and a second switch row;
a third conductor included among the first conductors and being
associated with the switches in the first switch row;
a fourth conductor included among the first conductors and being
associated with the switches in the second switch row;
a fifth conductor included among the second conductors and being
associated with a first switch in the first switch row and a second
switch in the second switch row;
a sixth conductor included among the second conductors and being
disposed adjacent to the fifth conductor;
a seventh conductor included among the first conductors and being
electrically connected to the fifth conductor and the sixth
conductor between the third conductor and the fourth conductor;
a fifth conductor being interrrupted between the seventh conductor
and the fouth conductor; whereby
the input signal on the first conductor is switched to the sixth
conductor by operation of the first switch and the input signal on
the fourth conductor is switched to the fifth conductor by
operation of the second switch.
20. A matrix of switches including:
a plurality of pairs of first conductors extending in a first
direction and having an input signal impressed on one of the
conductors in each of the pairs of first conductors;
a plurality of second conductors extending in a second direction
transverse to the first direction and defining one of the switches
with each of the pairs of first conductors, the second conductors
being movable relative to an associated pair of the first
conductors to short circuit the associated pair of first conductors
and thereby switch the input signal on the one conductor of the
associated pair of first conductors to the other conductor of the
associated pair of first conductors;
the switches being combined into a plurality of first groups of the
switches and a plurality of second groups of the switches;
a plurality of third conductors extending transversely to the first
direction and spaced in an electrically insulated relationship to
each other, each of the third conductors being connected to one of
the pair of first conductors associated with a different one of the
switches in one of the first groups of switches; and
a plurality of fourth conductors extending transversely to the
first direction and spaced in electrically insulated relationship
to each other, each of the fourth conductors being electrically
connected to a different one of the pair of conductors associated
with the switches in one of the second groups of switches;
whereby
the short circuiting of a particular pair of the first conductors
provides electrical continuity between a particular one of the
third conductors and a particular one of the fourth conductors.
21. The matrix of switches recited in claim 20 wherein the switches
are arranged in rows and columns and the first groups of swiches
correspond to the rows of the switches and the second groups of
switches correspond to the columns of the switches.
22. A matrix of switches responsive to an input signal and adapted
for use with a keyboard having a plurality of keys aligned in rows
and columns and individually actuable to control an opperation,
comprising:
a first backing member having a generally planar configuration;
a plurality of nonintersecting first conductors disposed on the
first backing member and adapted to receive the input signal;
a second backing member having a generally planar
configuration;
a plurality of nonintersecting second conductors disposed on the
second backing member;
a spacing member having a generally planar configuration and
dielectric characteristics, the spacing member being disposed in
juxtaposition to the first conductors on the first backing member
and the second conductors on the second backing member to normally
electrically insulate the first conductors from the second
conductors;
the second conductors extending in generally trasnverse,
nonperpendicular relationship to the first conductors to
substantially intersect the first conductors at a plurality of
points each defining the location of one of the switches of the
matrix and each of the switches being associated with one of the
keys of the keyboard;
portions of the spacing member defining a hole between an
associated one of the first conductors and an associated one of the
second conductors at each of the points of substantial intersection
to permit operation of the associated key of the keyboard to press
one of the associated first and second conductors through the
associated hole in the spacing member into electrical contact with
the other of the associated first and second conductors;
whereby
the input signal on the associated first conductor is switched to
the associated second conductor to control the operation.
23. The matrix of switches recited in claim 22 wherein the rows of
the switches are substantially perpendicular to the columns of the
switches and each of the second conductors is associated with an
individual one of the switches in the matrix of switches.
24. The matrix of switches recited in claim 22 wherein at least a
particular one of the second conductors is associated with a
particular pair of switches in different rows of the switches and
the particular second conductor is interrupted between the
particular switches to provide the particular switches with
independent switching characteristics.
25. The matrix of switches recited in claim 22 whrein a particular
one of the first conductors is adapted to receive the input signal
and a particular one of the second conductors is conneted to each
of the first conductors so that the input signal on the particular
first conductor is introduced to all of the other first
conductors.
26. A matrix of switches including:
a plurality of pairs of first conductors extending in a first
direction and having an input signal impressed on one of the
conductors in each of the pairs of first conductors;
a plurality of second conductors extending in a second direction
transverse to the first direction to define an area of close
proximity with each of the pairs of first conductors and to define
one of the switches at each of the areas of close proximity;
a spacing member disposed between the first conductors and the
second conductors, portions of the spacing member defining an
opening at each of the areas of close proximity;
the second conductors being movable relative to an associated pair
of first conductors and through the associated opening in the
spacing member to short circuit the associated pair of the first
conductors; whereby
the input signal on the one conductor of the associated pair of
first conductors is switched to the other conductor of the
associated pair of first conductors.
27. The matrix of switches recited in claim 26 wherein each of the
pairs of the first conductors defines at leastone of the switches
at the areas of close proximity with a respective one of the second
conductors so that the switches are aligned in rows extending in
the second direction and columns extending in the first direction.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to matrix switches which are
particularly adaptable to alphanumeric keyboards, and a method for
manufacturing the matrix switches at a relatively low price per
switch.
2. Description of Prior Art
It has been desirable to provide an alphanumeric keyboard, such as
those commonly used with typewriters, adding machines, and computer
input terminals, with a matrix switch including a separate switch
for each of the keys on the alpha-numeric keyboard. The matrix of
switches has permitted electrical control of the particular
operation with a resulting increase in speed and efficiency.
The switching matrices of the prior art have been manufactured by
elaborate and time-consuming processes. This has made electrically
actuated control of the particular operation prohibitively
expensive for some applications. For example, the switching
matrices of the prior art have relied upon electro-chemical
processes, such as metal deposition and etching processes, to
provide circuit conductors and switch contact surfaces. These
processes have included numerous expensive steps so that the
resulting switching matrices have had a relatively high cost per
switch.
Copending application Ser. No. 163,399, and now abandoned assigned
of record to the assignee of record of the present application,
discloses and claims a flexible switch having a first conductor
disposed on the surface of the first backing member and a second
conductor disposed on the surface of a second backing member. A
spacing member which normally separates the first and second
conductors is provided with an opening extending therebetween so
that the first and second conductors can be moved into relative
engagement through the opening. This enables the signal on the
first conductor to be switched to the second conductor. The backing
members and the spacing members have been formed from translucent
materials so that the switch can be backlighted to illuminate
indicia on the switch.
Also included in the prior art are collated cables which typically
are used to interconnect remote electronic assemblies. The collated
cables are typically manufactured by providing two spools of a
first and second backing material and a spool of wire for each of
the conductors desired in the cable. These wires can be fed across
guide means so that the conductors are sandwiched between the first
and second backing members in an electrically insulated
relationship to one another. The backing members can be bonded
together by heat and pressure to hermetically seal the structure.
This process for manufacturing collated cable can run at speeds up
to 40 ft. per minute and at costs significantly less than the
etching and deposition processes.
SUMMARY OF THE INVENTION
The low cost process for manufacturing collated cable can provide a
backing member having a plurality of electrically discrete
conductors disposed thereon to extend in a first direction. In a
similar manner, a second backing member can be provided and second
electrically discrete conductors disposed thereon to extend in a
second direction transverse to the first direction. The first and
second conductors can be maintained in a normally spaced
relationship by a dielectric spacing means disposed in contiguous
relationship with the first and second backing members. The
dielectric spacing means can be provided with a plurality of
openings each extending between an associated pair of the first and
second conductors. The openings will enable each of the associated
first and second conductors to be moved into relative engagement
through the associated opening to switch a signal from the
associated first conductor to the associated second conductor. In
this manner a switching matrix can be provided with a switch at the
intersection of each of the first conductors and each of the second
conductors.
The switches in the matrix can be disposed to accommodate a
particular alphanumeric keyboard so that each of the keys on the
keyboard can force one of the first conductors into engagement with
the associated second conductor. The number of switches per
conductor can be increased by extending the second conductors
through a pair of the switches and bisecting the second conductor
between the switches. In this manner, two discrete switches can be
defined at the intersection of two first conductors and a single
second conductor.
The process for manufacturing collated cables can be used
advantageously to assemble the backing members and the associated
conductors. Since this major step in the process of forming the
matrix switch can be performed at a high rate of speed, the
resultant matrix switch can be manufactured at a relatively low
cost. Furthermore, the collated cables can be disposed on
translucent backing members so that the individual switches can be
backlighted to illuminate the indicia of the keyboard. The
provision of low-cost switching matrices will enable the high speed
and efficiency of electrically controlled operations to be
economically available for a significant number of
applications.
The dielectric spacing means can have a generally planar
configuration with a plurality of apertures therein. Alternatively,
the spacing means can comprise a plurality of longitudinal members
extending in one of the first and second directions and cooperating
with each other to define the openings. These longitudinal spacing
members can be wound on spools and guided onto the first backing
member simultaneously with the first conductors. Thus, the
high-speed collating process can provide the spacing means as well
as the conductors.
These and other features and advantages of the invention will
become more apparent with a detailed description of the invention
in conjunction with the associated drawings.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view partially in phantom of an adding
machine including a switching matrix;
FIG. 2 is an assembled view of the switching matrix shown in FIG.
1;
FIG. 3 is a perspective view of an apparatus which can be used to
manufacture the switching matrix;
FIG. 3A is a cross-sectional view of a portion of the switching
matrix taken on line 3a--3a of FIG. 3;
FIG. 4 is a cross-sectional view of the switching matrix taken on
line 4--4 of FIG. 2;
FIG. 5 is a plan view of the keyboard of a standard typewriter;
FIG. 5A is an embodiment of a switching matrix which can be used in
conjunction with the typewriter keyboard shown in FIG. 5;
FIG. 5B is a further embodiment of a matrix switch which can be
used in conjunction with the keyboard shown in FIG. 5;
FIG. 6 is a plan view of a standard adding machine keyboard;
FIG. 6A is an embodiment of a switching matrix which can be used in
conjunction with the keyboard shown in FIG. 6;
FIG. 7 is one embodiment of a switching matrix which can be used
with a keyboard having keys spaced in symmetrical rows and
columns;
FIG. 7A is an additional embodiment of a matrix switch which can be
used with a keyboard having keys spaced in symmetrical rows and
columns;
FIG. 7B is a further embodiment of a switching matrix which can be
used with a keyboard having keys spaced in symmetrical rows and
columns;
FIG. 8 is a front elevational view of a bar clamp for terminating a
matrix switch;
FIG. 9 is a cross-sectional view of the bar clamp taken on line
9--9 of FIG. 8;
FIG. 10 is a plan view of the bar clamp for terminating the matrix
switch on a printed circuit board;
FIG. 11 is a cross-sectional view of the bar clamp taken on line
11--11 of FIG. 10.
FIG. 12 is a plan view of a further embodiment of the matrix switch
used in conjunction with an adding machine keyboard;
FIG. 13 is a cross-sectional view of the matrix switch taken on
line 13--13 of FIG. 12.
FIG. 14 is a plan view of an additional embodiment of the matrix
switch used in conjunction with a typewriter keyboard;
FIG. 15 is a plan view of an additional embodiment of the matrix
switch including longitudinal spacing members;
FIG. 16 is a cross-sectional view of the matrix switch taken on
line 16--16 of FIG. 15;
FIG. 17 is a plan view of still a further embodiment of the matrix
switch including the longitudinal spacing members; and
FIG. 18 is a cross-sectional view of the matrix switch taken on
line 18--18 of FIG. 17.
DESCRIPTION OF PREFERRED EMBODIMENT
An adding machine is shown generally in FIG. 1 and designated by
the reference numeral 11. The adding machine 11 has a keyboard 13
including a plurality of keys 15 arranged in rows and columns. By
selectively operating the keys 15, the operation of the adding
machine 11 can be controlled to provide a desired output which is
displayed, for example, on a display screen 17.
It is often desirable that the keys 15 on the keyboard 13
respectively actuate an individual electrical switch in order to
permit electrical control of the operation. Electrical control is
particularly desirable since it significantly increases the speed
and accuracy with which the operation can be performed.
Electrical control can be accomplished by means of a switching
matrix such as that shown generally at 19. The switching matrix 19,
which typically includes a switch 20 for each of the keys 15,
preferably is disposed in proximity to the keyboard 13 so that a
slight pressure on a particular one of the keys 15 will actuate the
associated switch 20.
In the preferred embodiment, the switching matrix 19 includes a
plurality of first electrically discrete conductors 21 extending in
a first direction, and a plurality of second electrically discrete
conductors 23 which may extend in a second direction transverse to
the first direction. A bar clamp 25 can provide means for
individually engaging the second conductors 23 to provide an
interface between the switches 20 and any electronics (not shown)
associated with the controlled operation.
It will be apparent to those skilled in the art that the adding
machine 11 is merely representative of many operations wherein the
benefits of electrical control can be achieved by means of the
switching matrix 19. For example, it will be obvious that the
switching matrix 19 can be advantageously used with other
alphanumeric keyboards, such as those associated with typewriters
and computer input terminals. Furthermore, although the adding
machine 11 is illustrated with a keyboard 13 wherein the keys 15
are disposed in symmetrically spaced rows and columns, the concepts
of the invention can be embodied to accommodate nonuniform
keyboards.
The switches 20 forming the switching matrix 19 can be of the type
disclosed and claimed in copending application Ser. No. 163,399 and
assigned of record to the assignee of record of the present
application. Thus, with reference to FIG. 2, it will be noted that
the switching matrix 19 can include a first backing member 27
defined by an inner surface 31 and an outer surface 33, and a
second backing member 29 defined by an inner surface 35 and an
outer surface 37. The first conductors 21 are preferably aligned on
the inner surface 31 of the backing member 27 so that they are at
least partially exposed in an electrically insulated relationship
to one another. For example, the first conductors 21 can be adhered
to the inner surface 31 so that they extend substantially parallel
to one another in a first direction. Similarly, the second
conductors 23 can be adhered to the inner surface 35 so that they
are exposed in an electrically insulated relationship to one
another, and generally extend in a second direction different than
the first direction.
The first and second backing members 27 and 29, respectively, can
be made from a suitable transparent or translucent material such as
the polyester designated by the tradename Mylar and manufactured by
the DuPont Corporation. This material is particularly desirable
since it is highly resistant to solvents which may be
advantageously used to clean the conductors 21 and 23. The
thickness of the backing members 27 and 29 may range from 0.003 to
0.015 inches with a thickness, such as 0.005 inches preferred.
Dielectric spacing means can be sandwiched between the inner
surfaces 31 and 35 of the first and second backing members 27 and
29, respectively, to maintain the conductors 21 and 23 in a
normally spaced relationship. In one preferred embodiment, the
spacing means comprises a spacing member 39 having a generally
planar configuration and portions thereof defining a plurality of
apertures 41. Each of the apertures 41 typically circumscribes an
imaginary line, such as the dotted line 43 which extends between an
associated one of the first conductors 21 and an associated one of
the second conductors 23. Preferably, the dotted line 43 is the
shortest line which connects the associated pair of the first and
second conductors 21 and 23, in which case it is substantially
perpendicular to the first and second backing members 27 and 29,
respectively.
The spacing member 39 can be formed from any suitable dielectric
material to maintain the first conductors in a normally
electrically insulated relationship with respect to the second
conductors 23. In a preferred embodiment, the spacing member is
formed from the polytetrafluoroethylene material marketed by DuPont
under the tradename Teflon. It is within the skill of those in the
art to form the spacing member 39 of other dielectric materials
which may provide additional advantages under some circumstances.
For example, a translucent material, such as Mylar, can be
advantageously used for the planar spacing member 39 if it is
desired to backlight the switches 20 of the switching matrix
19.
The first and second conductors 21 and 23, respectively, may have a
circular cross section with a diameter as small as 0.002 inches or
as large as 0.020 inches. However, in the preferred embodiment, the
conductors 21 and 23 are rectangular in cross section having a
thickness such as 0.003 inches and a width such as 0.015 inches.
The conductors 21 and 23 can include a suitable material, such as
copper or aluminum, having a high electrical conductivity and they
may be plated with a material, such as gold or rhodium, to enhance
the switching characteristics of the switches 20. To minimize the
plating area, rectangular cross-sectional dimensions for the
conductors 21 and 23 are preferably less than 0.005 and 0.030
inches.
In an embodiment where the first and second conductors 21 and 23,
respectively, have a width of 0.125 inches, the apertures 41 in the
spacing member 39 may be provided with a diameter such as 0.25
inches. These dimensions have been particularly desirable for
maintaining the associated first and second conductors 21 and 23 in
a normally spaced relationship while enabling them to be pressed
into relative engagement through the associated aperture 41. It is
this relative engagement of the associated first and second
conductors 21 and 23 which provides the switching characteristics
for an individual one of the switches 20 in the switching matrix
19.
This preferred operation of the switching matrix 19 can be more
easily understood with reference to FIG. 4 wherein one of the first
conductors 21 is illustrated to extend in a first direction across
the page of the drawings and some of the second conductors 23 are
illustrated to extend in a second direction into the page of the
drawings. The apertures 41 are defined in the dielectric spacing
member 39 between the associated first and second conductors 21 and
23 to extend coaxially with the dotted lines 43. In this
embodiment, the keys 15 are individually disposed for movement
along one of the dotted lines 43 to engage the outer surface 33 of
the first backing member 27, and to force the associated first
conductors 21 through the associated aperture 41 to electrically
engage the associated second conductor 23. It can be appreciated
that by operation of the keys 15, the signal present on the
associated first conductors 21 can be switched to the associated
second conductors 23 so that the signals present on the second
conductors 23 can activate the electronics (not shown) of the
operation. In this manner the selective operation of the keys 15
can provide electrical control of the operation, such as the adding
machine 11.
In the preferred embodiment, a relatively rigid supporting member
44 is disposed to engage the outer surface 37 of the second backing
member 29 to provide support for the switching matrix 19 so that
the second conductors 23 can maintain a substantially fixed
position. It will be appreciated by those skilled in the art that
the second conductors 23 can be moved to engage relatively
stationary first conductors, or alternatively, the associated first
and second conductors 21 and 23, respectively, can be
simultaneously moved into engagement through the associated
aperture 41.
Referring now to FIGS. 15 and 16, it will be noted that the first
conductors 21 and the second conductors 23 can extend in
substantially the same direction. In fact, a particular pair of the
first and second conductors 21 and 23, respectively, which form a
single switch 20, can be aligned in a plane substantially
perpendicular to the plane of the matrix switch 19, i.e., the plane
of the page. In such an embodiment, the pressing of one of the
first conductors 21 substantially anywhere along the length thereof
will move the pressed conductor 21 into electrical contact with the
associated second conductor 23.
Although the first and second conductors 21 and 23, respectively,
can have any cross-sectional configuration, it may be desirable
that they have rectangular cross-sectional configurations to
maximize the area of contact at a particular point of contact. It
may be further desirable that the second conductors 23 have a
greater width than the first conductors 21 in order to facilitate
their alignment during the construction of the switch.
As best illustrated in FIG. 16, the spacing means of the matrix
switch 19 can include a plurality of longitudinal spacing members
39' which typically extend in the same direction as the first
conductors 21 and which define an opening 41' in proximity to each
of the switches 20. Although the spacing members 39' can have any
cross-sectional configuration, their dimension between the first
and second backing members 27 and 29, respectively, should be
sufficient to provide the desired spacing between the first and
second conductors 21 and 23, respectively. Also, the distance
between the longitudinal spacing members 39' and the adjacent
switches 20 should be sufficient to enable the conductors 21 and 23
to be moved into electrical contact through the openings 41'.
In a preferred embodiment which includes polyester backing members
27 and 29 having a thickness of 0.004 inches, the conductors 21 and
23 have a width of 0.030 inches, and a thickness of 0.003 inches.
In this embodiment the longitudinal spacing members 39' have a
generally circular cross section providing a dimension between the
first and second backing members 27 and 29, respectively, of
approximately 0.009 inches. This provides a desired spacing of
0.003 inches between the associated first and second conductors 21
and 23, respectively. An adjacent pair of the spacing members 39'
can be disposed equidistant from the associated pair of conductors
21 and 23 and spaced from each other a distance within the
preferred range of 0.100 inches to 0.250 inches.
It will be noted that if the switches 20 are sufficiently close, as
at the left side of FIG. 15, they can be alternated with the
spacing members 39' to maintain the desired spacing between the
first and second conductors 21 and 23 in the switches 20. However,
if the switches 20 are spaced a significant distance, as at the
right side of FIG. 15, it may be desirable to provide a spacing
member 39' on each side of an associated switch 20. In the latter
case, there would typically be two spacing members 39' between an
adjacent pair of the switches 20.
A further embodiment of the matrix switch 19 can be provided in
accordance with FIGS. 17 and 18 wherein the longitudinal spacing
members 39' extend in a common direction with the first conductors
21 but intersect the second conductors 23. The switches 20 are
defined at the points of intersection between the first and second
conductors 21 and 23, respectively. It will be apparent that in
such an embodiment the adjacent switches 20, which are associated
with a particular one of the first conductors 21, may not be
separated by any spacing member 39'. Therefore, it may be desirable
to separate the second conductors 23 a distance sufficient to
insure that the activation of a single switch 20 does not also
activate the adjacent switch 20, which is associated with the same
first conductor 21. Since the adjacent switches 20 associated with
a particular one of the second conductors 23 will typically be
separated by one of the spacing members 39', the first conductors
21 can be provided with any suitable spacing.
In this embodiment wherein the first and second conductors 21 and
23, respectively, are transverse to each other, the spacing members
39' are generally supported by the second conductors 23. Thus, the
cross-sectional thickness of the spacing members 39' can be
substantially equal to the thickness of the first conductors 21
plus the desired spacing distance between the first and second
conductors 21 and 23, respectively.
Since the longitudinal spacing members 39' do not directly contact
both the first conductors 21 and the second conductors 23, their
dielectric characteristics may not be as important as those of the
planar spacing member 39. However, in the preferred embodiment, the
longitudinal spacing members 39' are formed from polyester
filaments which have relatively high electrical insulating
properties.
The embodiments of the matrix switch 19, which include the
longitudinal spacing members 39', are particularly advantageous
since they eliminate the expense of a separate planar spacing
member 39 and also the cost of a tool which would typically be used
to punch the apertures 41 in the spacing member 39. The embodiments
of FIGS. 15 through 18 are also desirable since they significantly
reduce the quality control problems associated with providing
apertures 41 which are free of burrs. In some cases, these burrs
can increase the operating force of an associated switch 20.
In a preferred process, the first conductors 21 can be disposed on
the inner surface 31 of the first backing member 27 are illustrated
in FIG. 3. The first backing member 27 can be disposed on a roll 10
and fed between a pair of rollers shown generally at 12. An
adhesive container 14 can be disposed between the roll 10 and the
rollers 12 to deposit a suitable bonding agent 22 on the inner
surface 31 of the first backing member 27. In a preferred method,
the first backing member 27 is purchased with a
temperature-sensitive adhesive precoated thereon. A typical
commercial product of this type is manufactured by Circuit
Materials Company and designated as CMC-153 polyester adhesive.
The first conductors 21 can be provided on the respective spools 16
to engage a guide roller 18 and to pass between the rollers 12 in
contiguous relationship with the backing member 27. The guide
roller 18 can be of the type including a plurality of
circumferential grooves 20 axially spaced on the surface of the
guide roller 18. Each of the first conductors 21 can be threaded
through one of the grooves 20 so that the first conductors 21 are
maintained in a spaced relationship, such as a parallel
relationship, as they pass between the rollers 12 to engage the
adhesive 22 on the first backing member 27. The rollers 12 exert a
pressure on the first conductors 21 and the first backing member 27
to provide them with a fixed relationship.
The bonding agent 22 can be a curable adhesive such as that
marketed by General Mills Chemical Company under the tradename
VERSALON. Such an adhesive can be partially cured prior to engaging
the first conductors 21 and fully cured after the first conductors
21 have been deposited on the first backing member 27. The rollers
12 can be heated to aid in the curing of the adhesive 22. The above
described process, which can be used to collate not only the first
conductors 21 but also the second conductors 23, is particularly
advantageous since the conductors can be collated at rates of up to
40 feet per minute. Thus, major steps in the formation of the
matrix switch 19 can be preformed at a high speed and a relatively
low cost.
This preferred method provides even further advantages for those
embodiments of the matrix switch 19 which include the longitudinal
spacing members 39'. For example, the spools 16 containing the
conductors 21 can be alternated with spools 16' containing the
longitudinal filaments 39'. Then the filaments 39' can be guided
through the corresponding grooves 26 so that the conductors 21 and
the filaments 39' are simultaneously and automatically deposited on
the backing member 27. The resulting combination is shown in cross
section in FIG. 3a.
This preferred method will offer an even greater cost reduction for
those particular embodiments including the spacing members 39'
since a separate member 39 need not be provided, punched, and
aligned. It is also apparent that the embodiments including the
longitudinal spacing members 39' permit a greater flexibility in
design. Thus, the cost of collating a different cable including the
spacing members 39' is significantly less than the cost of
providing different tooling to punch the apertures 41 in the planar
spacing member 39.
The concepts of the switching matrix 19 can be embodied to
accommodate the patterns of many different keyboards. In the
following detailed description of some of these embodiments,
elements which have characteristics and functions similar to the
elements in preceding embodiments will be provided with similar
reference numerals followed by a lower case letter corresponding to
the particular embodiment. The lower case letters will be chosen so
that consecutive letters correspond to consecutive embodiments. For
example, a matrix switch 19 can be embodied to accommodate a
conventional typewriter having a keyboard 13a, such as that shown
generally in FIG. 5. It will be noted that the keys 15a of the
keyboard 13a extend in a plurality of rows 45 and a plurality of
columns 47 having a first angular relationship with the rows
45.
A matrix switch 19a, shown in FIG. 5A, can be used with the
keyboard 13a of a standard typewriter. Preferably each of the
switches 20a is disposed to be operated when an associated key 15a
(FIG. 5) is depressed. For example, the switches 20a can be
disposed beneath the keys 15a so that the switches 20a are also
arranged in the rows 45a and the columns 47a. To accommodate such a
keyboard, the first conductors 21a can extend in a first direction,
such as the direction of the rows 45a, and the second conductors
23a can extend in a second direction different than the first
direction. This will provide the second conductors 23 with a second
angular relationship with respect to the rows 45a. In this
particular embodiment, each of the first conductors 21 is
associated with an entire row 45a of the keys 15a while each of the
second conductors 23a is associated with only one of the rows 45a.
This provides each of the switches 20a with discrete
characteristics so that the operation of one of the keys 15a
activates only one of the switches 20a.
A signal, such as that provided by a source of operating potential
42, can be introduced to each of the first conductors 21a so that
the operation of an individual switch 20a in the matrix 19a will
switch the operating potential 42 to the associated one of the
second conductors 23a. One method of introducing the operating
potential 42 to the first conductors 21a is to include among the
second conductors 23a a particular conductor 49 which preferably
does not extend through any of the switches 20a. The particular
conductor 49 can be soldered or welded to each of the first
conductors 21a so that a signal introduced to one of the first
conductors 21a is introduced to all of the first conductors 21a.
The welds or solder joints can be made through holes (not shown but
similar to the apertures 41a) in the spacing member 39a or,
alternatively, the spacing member 39a can be cut short so that the
first conductors 21a are exposed to the particular second
conductor. Of course, signals can also be introduced to the first
conductors 21 by a bar clamp similar to the bar clamp 25
terminating the second conductors 23.
The second backing member 29a can include a first edge 48 and a
second edge 50 between which the second conductors 23a extend. At
least one of the first and second edges 48 and 50, respectively,
can extend a distance such as 0.25 inches beyond the first backing
member 27 and the dielectric spacer 39a so that the second
conductors 23a are exposed on the extended edge. Each of the
extended edges 48 and 50 can register with one of the bar clamps
25a (FIG. 1) to provide an interface between the second conductors
23a and the electronics of the typewriter (not shown). In the
preferred embodiment only the first edge 48 is extended; however,
the second edge 50 can also be extended if redundant termination of
the second conductors 23a is desired.
A standard typewriter keyboard 13a (FIG. 5) can also be
accommodated by the matrix switch 19b embodied as illustrated in
FIG. 5B. In this embodiment consecutive rows 45b of the apertures
41b are designated by reference numerals 51, 53, 55, and 57. Also,
it will be noted that particular ones of the second conductors 23b,
such as the particular conductors 59 and 61, can extend through a
switch 20b in each of an alternate pair of rows 51, 53, 55, and 57.
For example, the particular conductor 59 extends through a switch
20b in each of the rows 53 and 57 and the particular conductor 61
extends through a switch 20b in each of the rows 51 and 55. Each of
the particular second conductors 23b extending through a pair of
switches 20b is preferably bisected between the associated pair of
the switches 20b. Thus, the bisected second conductors 23b provide
a plurality of third conductors 63 terminating on the second side
50b of the second backing member 29b and a plurality of fourth
conductors 67b terminating on the first side 48b of the second
backing member 29b. The bisecting of the second conductors 23b can
be accomplished by punching a plurality of holes, such as the holes
71, through the laminate so as to sever the particular second
conductors 23b between the associated pair of the switches 20b. In
the preferred embodiment, each of the holes 71 is defined in part
by discrete portions of one of the particular second conductors 23b
at a location between the adjacent rows 53 and 55 of the switches
20b.
Also in this embodiment, it is particularly desirable that both the
first and second edges 48b and 50b of the second backing member 29b
extend beyond the first backing member 27b and the dielectric
spacer 39b so that the third conductors 63 are exposed on the
second edge 50b and the fourth conductors 67 are exposed on the
first edge 48b. This embodiment of the matrix switch 19b is
particularly advantageous since a discrete switch is provided for
each of the keys on the keyboard but the number of second
conductors 23b is substantially one half the number illustrated in
the matrix switch 19a shown in FIG. 5A.
The concepts of this invention can be embodied to accommodate
keyboards wherein the keys are disposed in rows and columns which
are substantially perpendicular to the rows. Furthermore, the
spacing of the columns may not be symmetrical. These
characteristics are typified by a common adding machine keyboard of
the type shown generally at 13c in FIG. 6. The keys 15c of the
keyboard 13c are arranged in a first group 64 of numerical keys
disposed between a second and third group 66 and 68, respectively,
of function keys. The rows 45c of the keys 15c include
consecutively adjacent rows 69, 71, 73, and 75 which are common to
each of the groups 63, 65, and 67. Similarly, the columns 47c of
the keys 15c include the columns 77 and 79 in the first group 64
and the column 81 in the third group 68. The columns 47c can have a
first angular relationship, such as a perpendicular relationship,
with the rows 45c.
On the keyboard 13c the spacing between adjacent columns within
each of the groups, such as the columns 77 and 79 in group 64, can
be less than the spacing between adjacent columns in adjacent
groups, such as the columns 79 and 81 in the first and third groups
64 and 68, respectively. For example, in a preferred embodiment the
columns 77 and 79 are spaced 0.750 inches while the columns 79 and
81 are spaced 1.125 inches.
A matrix switch 19c embodied as illustrated in FIG. 6A can include
switches 20c spaced in accordance with the spacing of the keys 15c
of the keyboard 13c (FIG. 6). In this embodiment the first
conductors 21c extend in a first direction corresponding to the
rows 69, 71, 73, and 75 of the keys 15c. The second conductors 23c
preferably extend in a second direction having an angular
relationship with both the columns 47c of the key 15c and the first
conductors 21c. For example, the second conductors 23c can be
disposed at an angle 26.degree. 34' to the direction of columns
47c. At this angle some of the second conductors 23a such as the
conductors 83 and 85 will extend between a switch 20c in each of an
alternate pair of the rows 45c. For example, the conductor 83
extends through a switch 20c in each of the rows 69 and 73 and the
conductor 85 extends through a switch in each of the rows 71 and
75. The second conductors 23c extending through a pair of the
switches are preferably bisected between the pair of switches to
provide a terminal for each of the switches on one of the edges 48c
and 50c of the backing member 29.
Due to the increased spacing between the columns 47c in adjacent
groups, some of the second conductors 23c, such as the particular
conductor 87, may extend through only one of the switches 20c, such
as the associated switch 88. The particular second conductor 87
need not be bisected in which case the associated switch 88 is
terminated on both of the edges 48c and 50c of the second backing
member 29c.
The increased spacing between the columns 47c in adjacent groups
can also provide second conductors 23c which extend through a pair
of switches 20c disposed in non-alternate rows. Thus, the
particular second conductor 82 extends through the switches 84 and
86 in the rows 69 and 75. The particular second conductor 82 is
preferably bisected so that the switches 84 and 86 are individually
terminated on one of the edges 48c and 50c.
The concept of the switching matrix can be embodied to accommodate
a keyboard having a plurality of keys aligned in rows and columns
which are evenly spaced. Such a matrix might include the switches
20d which are illustrated in FIG. 7 to be symmetrically spaced to
correspond to the spacing of the keys. In FIG. 7, 20 of the
switches 20d are consecutively lettered from A to T and disposed in
four rows and five columns. The switching matrix 19d is merely
representative of that which can be used with any symmetrical
keyboard having any number of keys. Furthermore, although the
switches A to T have a symmetrical spacing of 0.75 inches in the
preferred embodiment, the concept of the invention can be applied
to any spacing of the keys and switches.
As illustrated in FIG. 7, the switches A to T are arranged in rows
83 and columns 85 and the columns 85 have an angular relationship
such as a perpendicular relationship to the rows 83. The first
conductors 21d can extend individually through the rows 83, and the
second conductors 23d can be disposed in an angular relationship
with both the rows 83 and columns 85. The second conductors 23d can
include a series of conductors, such as the series of conductors 87
and 89, for each of the columns 85 of the switches A to T. The
number of conductors in each of the series of conductors 87 and 89
can be equal to the number of rows 83 of the switches 20d. This
will enable conductors in each of the series of conductors 87 and
89 to extend through one of the switches 20d in the associated
column 85 of switches 20d. This configuration can provide a
terminal for each of the switches A to T in accordance with the
corresponding letters on the first edge 48d.
In the preferred embodiment, the switches 20d are disposed on 0.75
inch centers and the second conductors 23d have a maximum width of
0.125 inches. With these dimensions, the matrix switch 19d could be
expanded to include six switches 20d in each of six rows 45d.
If the columns 85 are more closely spaced, it may be advantageous
that some of the second conductors 23 extend through more than one
of the switches 20. Under such circumstances, the matrix switch 19e
shown in FIG. 7A may be particularly desirable. In this embodiment,
some of the second conductors 23e may be shared between adjacent
series of conductors, such as the series 87e and 89e. For example,
the particular conductors 91 and 93 are included in both the series
of conductors 87e and 89e. These particular conductors 91 and 93
extend through a switch in each of an adjacent pair of the columns
85e so that it is desirable to bisect the particular conductors 91
and 93 between the associated switches. Thus, the particular
conductor 91 is bisected between the switches B and K and the
particular conductor 93 is bisected between the switches G and P.
This will provide each of the associated switches with a discrete
terminal. Thus, in the switching matrix 19e, the second conductors
23e of each of the switches A to T are terminated in accordance
with the respective letters on the edges 48e and 50e of the second
backing member 29e. It will also be noted that the common line 49e
is shown to be welded to each of the first conductors 21e through a
plurality of apertures 38 in the spacing member 39e.
Since a single second conductor 23e can accommodate more than one
switch, the ultimate size of the matrix is significantly increased.
For example, if the switches 20e are on 0.75 inch centers and the
second conductors 23e have a maximum width of 0.125 inches, the
matrix switch 19e can be expanded to accommodate 12 switches 20e in
each of 12 rows. Even larger matrices can be made if the spacing of
the switches 20e is increased or the width of the second conductors
23e is decreased.
A keyboard having symmetrically spaced keys can be provided with a
switching matrix of still another embodiment wherein the angular
relationship of the rows 45 and columns 47 is the same as the
angular relationship of the first conductors 21 and the second
conductors 23. Thus, the matrix switch can be embodied, as in FIG.
7B, to accommodate switches symmetrically spaced in rows 45f,
including an adjacent pair of particular rows 95 and 97. Particular
ones of the first conductors 21f can individually extend through
the switches 20f in each of the rows 45f. For example, a particular
conductor 99 can extend through the switches 20f in the row 95 and
a particular conductor 101 can extend through the switches 20f in
the row 97. Additionally, an intermediate first conductor 21f can
extend between each of first conductors 21f which pass through the
switches 20f in an adjacent pair of the rows 45f. For example, the
intermediate conductor 103 can extend between the particular
conductors 99 and 101.
Similarly, the second conductors 23f can include a particular
conductor 105 and a particular conductor 107 each extending through
an adjacent pair of the columns 47f. The second conductors 23f can
also include an intermediate second conductor 109 extending between
the particular conductors 105 and 107.
In addition to the apertures 41f, the dielectric spacing member 39
can include a plurality of apertures 111 which are disposed at the
points of intersection between the particular first conductor 103
and each of the second conductors 23f. The conductor 103 and each
of the second conductors 23f can be electrically connected by
welding or soldering through each of the apertures 111. Each of the
particular second conductors passing through the switches 20f, such
as the conductors 105 and 107, are preferably bisected between the
particular first conductors 99 and 103. This can be accomplished by
punching a hole, such as the hole 113, through the laminate in a
manner similar to the punching of the holes 71f so that the
conductors 105 and 107 are severed. The intermediate first
conductors 103 is also preferably bisected between the particular
second conductors 105 and 107 and on one side of the intermediate
second conductor 109. This bisecting can be accomplished by
punching a hole, such as the hole 115, through the laminate so that
the intermediate first conductor 103 is severed at the location of
the hole 115.
In this manner, the switches disposed on the particular rows 95 and
97 can be provided with discrete terminals on one of the edges 48f
and 50f as illustrated by the respective letters A to T. An
additional pair of the rows 45f of switches 20f can be accommodated
by the second conductors 23f so that the switches 20f associated
therewith are terminated on the opposite edge 50f of the second
backing member 29. As previously noted, it is desirable in such an
embodiment to bisect the second conductors typically by punching
the holes 71f through the laminate between the associated pairs of
the rows 45f.
The matrix switch 19 of the present invention can be embodied as
illustrated in FIG. 12 to terminate on a standard collated cable
adapter board 165 which has a plurality of conductors 167 printed
thereon. In this particular embodiment, the first conductors 21g
are arranged in pairs, and each of the pairs is associated with one
of the switches 20g. For example, a particular pair of the
conductors 21g include a conductor 171 and a conductor 173, both of
which are associated with the key having the indicia 7. As in some
of the previous embodiments, each of the second conductors 23g is
associated with a particular row of the switches 20g.
The dielectric spacing member 39g separates the first and second
conductors 21g and 23g, respectively, except in the general areas
of their intersection. In each of these areas, one of the keys 15
(FIG. 4) is disposed to press the associated pair of the first
conductors 21g into electrical contact with the associated second
conductor 23g. Thus, by pressing an individual key 15, the signal
present on one of the conductors in the associated pair of first
conductors 21g passes through the associated second conductor 23g
to the other of the conductors in the particular pair of first
conductors 21g. For example, by pressing the key associated with
the indicia 7, the signal present on the conductor 171 is shorted
across the associated second conductor 23g to the conductor 173. It
is apparent that in this particular embodiment the second
conductors 23g function primarily to short the conductors 21g in a
particular pair of the conductors 21g. Also, it will be noted that
generally speaking, the first conductors 21g are not directly and
permanently connected to the electronics associated with the
particular operation.
A collated cable 175 can be disposed with its substantially
parallel conductors 177 extending transverse to the first
conductors 21g and respectively terminating on the conductors 167.
Generally, the switches 20g can be connected to the conductors 177
in accordance with random groupings of the switches 20g. For
example, the switches 20g can be formed into a plurality of first
groups including all of the switches 20g and a plurality of second
groups including all of the switches 20g. Each of the switches 20g
is included in one of the first groups and one of the second
groups, so that the number of switches 20g can be no greater than
the product obtained by multiplying the number of first groups by
the number of second groups. The conductors 177 can be designated
to correspond respectively to one of the first or second groups of
switches 20g. Then, each of the pairs of first conductors 21g can
be electrically connected to those conductors 177 which have the
particular first and second group designations corresponding to the
associated switch.
Referring to FIG. 12, it will be noted that the conductors 177
include particular conductors 179 and 181 which correspond to two
random groups of switches 20g among the function switches shown
generally at 183. Also, the particular conductors 187, 189, and 191
correspond to the three random groups of switches 20g among the
numbered switches shown generally at 185. The particular conductor
191 also corresponds to the group of switches to the right of the
numbered switches 185. The pairs of conductors 21g for each of the
switches 20g can be connected as previously described. This is
merely one example of how the switches 20g can be formed into first
groups to facilitate repairs, wherein a particular failure can be
localized to the function switches or the number switches.
Of course, the first and second groups of switches 20g can
correspond respectively to the rows and columns of the switches
20g. Then, each of the pairs of first conductors 21g can be
electrically connected to those conductors 177 which have the
particular row and column designations corresponding to the
associated switch.
This particular matrix switch can be formed as a laminate as shown
in FIG. 14. The first backing member 27g and the dielectric spacing
member 39g can extend substantially across the entire matrix switch
19g with the first conductor 21g sandwiched therebetween.
A separate collated cable including the backing member 29g and the
shorting second conductors 23g can be disposed on the side of the
spacing member 39g opposite the first conductors 21g to form the
switches 20g. A further collated cable 175 including the conductors
177 can be simultaneously located on the side of the spacing member
39g opposite the first conductors 21g, typically in spaced
relationship to the switches 20g.
In addition to the apertures 41g which can be formed between the
first and second conductors 21g and 23g, respectively, the spacing
member 39g can also be provided with an aperture 193 at each of the
points of intersection where one of the first conductors 21g is to
be connected to one of the conductors 177. In such an embodiment,
the associated conductors 21g and 177 are connected through the
associated apertures 193. Alternatively, at each of these points of
intersection, the associated conductors 23g and 177 can be
soldered, resistance-welded, ultransonically welded, or otherwise
connected by melting the backing member 29g and the dielectric
spacer 39g at each of the points of connection. Such a weld is
shown generally at 195 in FIG. 13. Although the conductors 23g and
the conductors 177 are illustrated to be included in separate
collated cables, it will be apparent that these conductors can be
collated on a single backing member.
As illustrated in FIG. 14, a matrix switch 19 similar to that shown
in FIG. 12 can be provided to accommodate a standard typewriter
keyboard. In such an embodiment, the first and second conductors
21h and 23h may be oriented in substantially perpendicular
directions. It is of interest to note that the pairs of first
conductors 21h include a first and second particular pair of
conductors which are designated generally by the reference numerals
197 and 199, respectively. The second conductors 23h also include a
particular pair of conductors which is designated by the reference
numeral 201. These conductors are of particular interest since the
particular first conductors 197 pass through the switches
associated with both the letter B and the "space." Thus, the
particular conductors 197 violate the general rule that a single
pair of the second conductors 23h should be associated with only a
single switch 20h.
In such a case, the particular conductors 197 can be cut or
otherwise provided with a discontinuity between the associated pair
of switches designated B and "space." Then the particular
conductors 197 can be soldered or otherwise connected to the
particular conductors 201 as illustrated generally at 203.
Similarly, the particular conductors 201 can be connected to the
conductors 199 as illustrated generally at 205. The conductors 199
can be connected to the conductors 177h of the collated cable 175h
in the manner previously discussed.
Referring again to FIG. 1, it will be noted that the matrix switch
19 can register with the bar clamp 25 to provide an interface
between the switch 20 and the associated electronics (not shown) of
the controlled operation. Referring now to FIG. 9, it will be noted
that the bar clamp 25 can include first retaining means 125 which
cooperates with a clamp plate 127 to receive the ends of the second
conductors 23. In such an embodiment, the second conductors 23 can
face the first retaining member 125 so that the outer surface 37 of
the backing member 29 contacts the clamp plate 127. The first
retaining member 125 preferably includes portions 130 which define
a plurality of first slots 131 each aligned with and receiving one
of the second conductors 23. The matrix switch 19 may be maintained
in a substantially fixed relationship with the bar clamp 25 by the
frictional engagement of the portions 130 and the conductors 23,
and the frictional engagement of the clamp plate 127 with the
backing member 29.
A plurality of conductors 133 preferably extend from an outer
surface of the first retaining member 125 to contact respectively
the second conductors 23. The conductors 133 are preferably formed
from discrete strips of material each having a relatively high
electrical conductivity.
Each of the conductors 133 can be constructed to exert a force upon
the associated second conductors 23 to enhance the electrical
contact therebetween. For example, the conductors 133 can include
first portions 135 having a substantially fixed relationship with
the first retaining member 125, and the portions 137 slidingly
engaging the first retaining member 125 interiorly of the slots
131. Third portions 139 of the conductors 133 can extend between
the first and second portions 135 and 137, respectively, to contact
the associated second conductors 23. If the third portions 139 are
normally biased to extend from the slots 131, then they will exert
a pressure upon the second conductors 23 when the portions 130
contact the second conductors 23.
It will be apparent to those skilled in the art that the first
retaining member 125 can be molded from an insulating material with
the portions 135 of the conductors 133 embedded in the first
retaining member 125. It may be desirable, however, that the
conductors 133 more loosely engage the first retaining member 125
to facilitate replacement of the conductors 133. In such an
embodiment, the first retaining member 125 can be constructed to
define a plurality of slots 141. The slots 141 preferably extend
from each of the slots 131, along the surface of the member 125
facing toward the switches 20, and terminate at the surface of the
member 125 facing away from the switches 20.
A second retaining member 143 can be disposed to engage the first
retaining member 125 to form a channel 145 with each of the slots
141. The conductors 133, which preferably extend through the
channels 145 are loosely held in a substantially fixed relationship
between the first and second retaining members 125 and 143,
respectively. Portions 146 of the conductors 133 extending from the
channels 145 can be configured to facilitate their connection to
conductors 148 of the associated electronics. In this manner, the
bar clamp 25 interfaces the matrix switch 19 with the associated
electronics by providing electrical continuity between the
conductors 23 and the conductors 148.
It will be apparent to those skilled in the art that the bar clamp
25 is particularly adapted for use with a clamp plate 127, such as
a board having a circuit 129 printed on the surface thereof. As
illustrated in FIGS. 10 and 11, the first retaining member 125
preferably contacts the outer surface 37 of the backing member 29
so that the second conductors 23 are forced into electrical contact
with the circuit 129. In such an embodiment, the conductors 133 may
not carry any signal, in which case their primary function is to
exert pressure upon the backing member 29 to facilitate the
electrical contact between conductors 23 and the circuit 129. It
will be appreciated by those skilled in the art that this function
can be performed by any biasing means preferably extending between
the first retaining member 125 and the backing member 29.
The first and second retaining members 125 and 143, respectively,
and the conductors 133 can be constructed in a subassembly. In such
a subassembly, the first and second retaining members 125 and 143,
respectively, may define at least a pair of apertures 147 extending
substantially perpendicularly to the clamp plate 127. A tubular
member 149 for each of the apertures 147 can be provided with a
flanged end 153 and a flangable end 151. After the conductors 133
have been disposed in the slots 141, the second retaining member
143 can be brought into cotiguous relationship with the first
retaining member 125 so that the apertures 147 in the first and
second retaining members 125 and 143, respectively, are aligned. In
this position, the second member 143 caps the slots 141 to
partially define the channels 145. With each of the apertures 147
aligned, the flangable end 151 of each of the tubular members 149
can be passed through the respective apertures 147 until the
flanged end 153 contacts the second retaining member 143. Then the
flangable end 151 can be flanged to contact the first retaining
member 125 and thereby complete the subassembly.
The clamp plate 127 can be constructed to define a hole 155 having
a coaxial relationship with each of the apertures 147. A threaded
member, such as the bolt 157, can be passed through each of the
tubular members 149 and the associated holes 155 until the head of
the bolt 157 engages the flanged end 153. A nut 159 can be screwed
on the threads of the bolt 157 to engage the clamp plate 127. In
this manner, the subassembly including the conductors 133 can be
held in fixed relationship with the clamp plate 127, with the
backing member 29 and the conductors 23 sandwiched therebetween. It
may also be desirable that the backing member 29 be provided with a
hole 161 preferably aligned with each of the apertures 147 to
receive the bolts 157. This embodiment will enable the matrix
switch 19 to be bolted to the bar clamp 25 and the clamp plate
127.
The switching matrix 19 of the present invention provides a
significant advance over the prior art. Major steps in the
formation of each of the embodiments illustrated and described can
be accomplished in accordance with the high-speed methods
associated with collated cable, so that the switching matrix 19 can
be constructed at a significantly low cost per switch.
Although the switching matrix 19 can be formed with the planar
spacing member 39, particular embodiments may be more
advantageously constructed with the longitudinal spacing members
39'. The longitudinal spacing members 39' can be collated on the
backing member 27 simultaneously with the disposition of the first
conductors 21 thereon. This not only eliminates a separate part,
but also significantly reduces problems associated with alignment
and quality control. The matrix switch 19 can be adapted to operate
in conjunction with many of the standard keyboards associated with
typewriters, adding machines, and computers, etc.
The matrix switch 19 can be terminated by the bar clamp 25 not only
to hold the switching matrix 19 in a fixed position with respect to
the keyboard 13, but also to provide the automatically biased
conductors 133 which receive the signals from the second conductors
23 and provide an interface with the associated electronics.
Alternatively, the bar clamp 25 can be used in conjunction with a
board 127 having a circuit 129 printed thereon in which case the
biased conductors 133 force the second conductors 23 into
electrical contact with the circuit 129 on the board 127.
Although this application has been disclosed and illustrated with
reference to particular applications, the principles involved are
susceptible of numerous other applications which will be apparent
to persons skilled in the art. The invention is, therefore, to be
limited only as indicated by the scope of the appended claims.
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