U.S. patent number 3,728,652 [Application Number 05/054,898] was granted by the patent office on 1973-04-17 for key apparatus and arrangement thereof.
This patent grant is currently assigned to Canon Kabushiki Kaisha. Invention is credited to Tatsuo Nishikawa.
United States Patent |
3,728,652 |
Nishikawa |
April 17, 1973 |
KEY APPARATUS AND ARRANGEMENT THEREOF
Abstract
A key apparatus includes a magnetic reed switch and at least one
magnet forming a magnetic portions for energizing the reed switch.
the magnetic portion having a plurality of magnetic poles disposed
to produce substantially parallel magnetic fluxes opposite in sense
so that the reed switch is maintained open under the influence of
both of said substantially parallel magnetic fluxes opposite in
sense when the key is in normal position and that the reed switch
is closed under the influence of one of said magnetic fluxes. A
plurality of such key apparatuses are arranged so as to form
columns and rows and in such a manner that all the magnetic
portions in any common column or row faces in the same direction
but that the adjacent magnetic portions in any common row or column
face in opposite directions, whereby the key board can be
compact.
Inventors: |
Nishikawa; Tatsuo (Tokyo,
JA) |
Assignee: |
Canon Kabushiki Kaisha (Tokyo,
JA)
|
Family
ID: |
13047047 |
Appl.
No.: |
05/054,898 |
Foreign Application Priority Data
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|
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Jul 18, 1969 [JA] |
|
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44/57133 |
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Current U.S.
Class: |
335/207; 341/32;
335/206 |
Current CPC
Class: |
H01H
36/004 (20130101); B41J 5/08 (20130101) |
Current International
Class: |
H01H
36/00 (20060101); H01h 041/08 (); H01h
003/12 () |
Field of
Search: |
;335/205,207,206 |
References Cited
[Referenced By]
U.S. Patent Documents
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|
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3260819 |
July 1966 |
Scuitto et al. |
3533029 |
October 1970 |
Steinbach et al. |
|
Primary Examiner: Envall, Jr.; Roy N.
Claims
What is claimed is:
1. A key apparatus comprising a key movable into an operative
position by an external force applied thereto and returnable to a
normal position upon release of said external force, a member
movable in response to movement of said key, a magnetic unit
secured to said member for generating substantially parallel
magnetic fluxes at fixed spaced intervals and having opposite
polarity, comprising a first magnetic portion having opposite poles
and a second magnetic portion having opposite poles, the polarity
of the poles of said second magnetic portion being oppositely
disposed with respect to the polarity of the poles of said first
magnetic portion, the first magnetic portion being magnetically
separated from the second magnetic portion by a non-magnetized
region, and a reed switch disposed adjacent to and spaced from said
magnetic unit and having two contact elements enveloped therein,
said reed switch keeping said contact elements opened when said key
is in the normal position, and said reed switch being operated to
close said contact elements under the influence of a substantial
flux component generated by one of said first and second magnetic
portions of said magnetic unit when said key is in the operative
position.
2. A key apparatus as defined in claim 1, wherein said first and
second magnetic portions comprise magnets respectively, and said
magnets are disposed spaced from each other to form a magnetic gap
therebetween.
3. A key apparatus as defined in claim 1, wherein said reed switch
is disposed closely spaced from and in substantially parallel
relationship with respect to said first and second magnetic
portions.
4. A key apparatus comprising a key movable into an operative
position by an external force applied thereto and returnable to a
normal position upon release of said external force, a member
movable in response to the movement of said key, a magnetic unit
comprising two magnet means each having different magnetic flux
density and disposed in parallel with each other for generating
substantially parallel magnetic fluxes at fixed spaced intervals
and having opposite polarity and a reed switch, having two contact
elements enveloped, disposed at an area where said magnetic fluxes
generated by said two magnet means interact with each other and
closely spaced from said magnet means, said reed switch keeping
said contact elements opened when said key is in the normal
position, and said reed switch being operated to close said contact
elements under the influence of one magnet means having higher
magnetic flux density than the other magnet means when said key is
in the operative position.
5. A key apparatus as defined in claim 4, wherein said reed switch
is normally located adjacent the spaced area between said two
magnet means disposed in parallel, and one magnet means is brought
into an opposed position upon depression of said key.
6. A key arrangement comprising a plurality of key apparatus
arranged in a matrix array each comprising a key movable into an
operative position by an external force applied thereto and
returnable to a normal position upon release of said external
force, a supporting member movable in response to movement of said
key, a magnetic unit comprising a first magnetic portion having
opposite poles and a second magnetic portion having opposite poles,
the polarity of the poles of said second magnetic portion being
oppositely disposed with respect to the polarity of the poles of
said first magnetic portion, the first magnetic portion being
magnetically separated from the second magnetic portion by a
non-magnetized region, and a reed switch disposed spaced from and
in parallel relationship with said first and second magnetic
portions and perpendicular to the moving direction of said
supporting member, wherein each reed switch opposed to its
respective magnetic unit on one column in said matrix array is
arranged on one side with respect to each supporting member, and
each reed switch opposed to its respective magnetic unit on the
adjacent column is arranged on the opposite side with respect to
each supporting member.
Description
BACKGROUND OF THE INVENTION
1. FIELD OF THE INVENTION
This invention relates to a key apparatus, and more particularly to
a key apparatus having a reed switch (hereinafter referred to as
"reed switch") and magnets for energizing the reed switch and to an
novel arrangement of such key apparatus.
2. DESCRIPTION OF THE PRIOR ART
A reed switch has been widely in use as the input device for an
electronic computer or the like. Such a reed switch comprises a
glass tube hermetically enclosing therein inert gas and a pair of
magnetically and electrically conductive reeds (hereinafter
referred to as "reeds") disposed partly in overlapping relationship
so as to serve as contact means. The reeds are also flexible.
Such reeds are normally open, but when a magnetic field is applied
thereto by bringing a magnet close thereto, the pair of
electrically conductive reeds are intensively subjected to the
magnetic flux from the magnet so that the contact portions of the
reeds are caused to attract each other into contact and establish
electrical connection therebetween. When the extraneous magnetic
field is decreased, that is, when the magnet is moved away from the
reeds so as to reduce the density of the magnetic flux affecting
the contact means, these contact portions are opened and
electrically disconnected from each other.
It has been widely in practice to use a permanent magnet as the
source of such magnetic field. One of the known arrangements of the
magnet with respect to the reed switch of the described type is
such that the magnet is disposed in a direction parallel to an axis
of the reed switch or to the direction of extension of the reeds
(the direction of the magnet is that determined by the opposite
poles thereof). In such an arrangement, the magnet is moved axially
of the reed switch to control the latter so that the contact
portions of the reed switch are closed by a greater density of
magnetic flux from the magnet when the magnet is centered with
respect to the reed switch and that the contact are opened when the
magnet is deviated from the contact portions.
Another known arrangement of the magnet is such that the magnet is
disposed in a direction normal to the major axis of the reed switch
or to the direction of extension of the reeds of the reed switch.
With this arrangement, the magnet is also moved axially of the reed
switch to control the latter so that the contacts of the reed
switch are caused to attract each other and closed by a greater
density of magnetic flux when the magnet has come closer to one of
the pair of reeds (or when the magnet is deviated from the
contacts) and that the contacts are opened when the magnet is
centered with respect to the contact means.
As has been described above, the magnet for controlling the reed
switch of this type is moved along the major axis of the reed
switch and usually the magnet is directly coupled and fixed to the
key. For this reason, the reed switch must be fixed to the key
board in perpendicular relationship therewith and this has led to a
greater height of the key board.
Consequently, the key apparatus of the above-described construction
has been incompatible with the increasing requirement for the
compactness of electronic computer, especially of the desk
type.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a key apparatus
and arrangement thereof which can reduce the size or height of the
key board.
It is another object of the present invention to provide a key
apparatus which can reduce the distance of travel of the magnet for
controlling the reed switch, namely, reduce the key stroke.
It is still another object of the present invention to provide a
key apparatus having a plurality of magnets for controlling the
reed switch.
It is yet another object of the present invention to provide a key
apparatus in which magnets are moved perpendicularly to the major
axis of the reed switch to control the operation of the latter.
It is still another object of the present invention to provide an
effective arrangement of such key apparatus.
These and other objects and advantages of the present invention
will become readily apparent from the following illustrative
description taken in conjunction with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view showing an example of the magnetic
portion constituting the key apparatus according to the present
invention;
FIG. 2 is a perspective view showing the positional relationship
between the magnetic portion of FIG. 1 and the reed switch as the
latter is in open position.
FIGS. 3A and 3B are side views showing the relationship between a
pair of magnets forming the magnetic portion of FIG. 1 and the reed
switch when the latter is opened and closed by the magnets.
FIG. 4 is a perspective view partially broben of the key apparatus
incorporating the magnetic portion and reed switch.
FIG. 5 is a side view showing the key apparatus when the key is
depressed or the reed switch is closed.
FIGS. 6A and 6B are perspective views showing further examples of
the magnetic portion according to the present invention.
FIG. 7 is a bottom plan view showing the input key board of a desk
type electronic computing machine incorporating a number of such
key apparatuses as shown in FIGS. 4 and 5.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1, there is shown an arrangement of magnets for
controlling the reed switch. A metallic base plate 11 carries
thereon a bed 12 formed of non-magnetic material, and a pair of
magnets 13 and 14 are securely mounted on the bed 12. The pair of
magnets, which have their magnetic poles at the opposite ends
thereof, are arranged in such a manner that their adjacent poles
are opposite in polarity, thereby constituting a magnetic portion
having four magnetic poles. As shown in FIG. 1, there is produced a
magnetic flux M.sub.1 between poles N.sub.1 and S.sub.1, a magnetic
flux M.sub.2 between poles N.sub.2 and S.sub.2, a magnetic flux
M.sub.12 between poles N.sub.1 and S.sub.2, and a magnetic flux
M.sub.21 between poles N.sub.2 and S.sub.1. However, the magnets 13
and 14 are opposite in magnetic sense and accordingly the magnetic
fluxes M.sub.1 and M.sub.2 are also opposite in magnetic sense,
whereby these two magnetic fluxes act to negate each other in the
adjacent portions of the magnets. As a result, the magnetic fluxes
M.sub.1 and M.sub.2 are least intense at the center O between the
two magnets and more intense in the portions farther from that
center. This also holds true with the magnetic fluxes M.sub.12 and
M.sub.21. In other words, the magnetic fluxes M.sub.1, M.sub.2,
M.sub.12 and M.sub.21 gradually increase their densities in
proportion to the distance from the center O.
Therefore, if a reed switch 15 is disposed in such a manner that
the contact means 16 thereof is positioned at the center O as shown
in FIG. 2, then the contact means 16 will be least subjected to the
negative fluxes, thereby to maintain open. The magnetic fluxes
M.sub.12 and M.sub.21 which are present at the opposite ends of the
reed switch 15 cannot affect the contact means 16
significantly.
FIG. 3A shows the reed switch 15 in open position. By depressing
the base plate 11, the bed 12 and the magnets 13 and 14 are moved
down together so that the magnet 13 is just opposed to the reed
switch 15, as shown in FIG. 3B. When the contact means 16 of the
reed switch 15 is thus moved away from the center O, the reed
switch 15 is brought within the influence of the magnetic flux
M.sub.1 from the magnet 13. This means that the magnetic flux
M.sub.1 passes through the reed switch 15 and causes the contact
means 16 thereof to be closed and establish electrical
connection.
While the base plate 11 has been shown and described to be
depressed, the same result may be attained by arranging the base
plate 11 so as to be raised thereby to bring the reed switch 15
within the influence of the magnetic flux M.sub.2 from the lower
magnet 14.
Referring to FIGS. 4 and 5, there is shown the entire key apparatus
whose essential portion has been shown in FIGS. 1 to 3. A holder
plate 16' securely holds a pair of downwardly extended portions 17
and 17', which have aligned grooves 18 and 18' formed in their
respective inner side walls for slidably receiving the
above-described base plate 11.
The base plate 11 extends upwardly through a slot (not shown)
formed in the holder plate 16' so as to provide three divided
extensions 20, 20' and 21. The extension 21 is shorter than the
other extensions 20 and 20', on which a key 19 is fixedly mounted.
A coil spring 22 is mounted around the extension 21 and between the
key 19 and the holder plate 16' so that the coil spring 22 acts to
raise the key 19. The base plate 11 in the lower portion thereof
has secured thereto the bed 12 carrying the magnetic portion
comprising two magnets 13 and 14, as described previously, and the
bed 12 is engaged with the underside of the holder plate 16',
thereby to serve as stopper means for preventing the base plate 11
from being forced out through the holder plate 16' by the force of
the coil spring 22. In the portion of the underside of the holder
plate 16' which corresponds to the bed 12, there may be provided a
layer of elastic material 23 such as felt, rubber or the like so as
to prevent any noise from being produced by the stopper means when
the key 19 is returned by the spring 22.
The holder plate 16' further has a pair of holder terminals 24 and
24' downwardly extending therefrom so that in the normal or
depressed position the reed switch 15 may be substantially in
alignment with the clearance between the magnets 13 and 14 or that
the contact means 16 of the reed switch 15 is positioned at the
center O, i.e. the reed switch is subjected to the influence of the
magnetic fluxes M.sub.1 and M.sub.2. Also, the stroke of the key 19
is such that when depressed the magnet 13 travels down until the
reed switch 15 is brought within the influence of the magnetic flux
M.sub.1 from that magnet.
Such position setting may be achieved by selecting the height of
restraining means 29 and 29' extended upwardly from the holder
plate 16'. The restraining means 29 and 29' may have the top ends
thereof covered with layers of elastic material 30 and 30' such as
felt, rubber or the like to prevent any noise which would otherwise
occur when the restraining means strike the underside of the key
19.
The key apparatus is also provided with top and bottom plates 25
and 31 constituting the key board.
FIGS. 6A and 6B show further examples of the magnetic portion on
the bed 12 fixed to the base plate 111. In FIG. 6A, use is made of
a single magnet 126 of rectangular cross section having therein a
pair of electrodes. This magnet 126 has four magnetic poles
disposed at the four corners thereof in such a manner that adjacent
poles are opposite in polarity. The effect of such magnet upon the
reed switch is entirely the same as that described with respect to
the embodiment of FIGS. 1 and 2, and therefore the detailed
description thereof is omitted herein. However, it should be noted
that the use of such a single magnet reeds to a greater ease with
which the magnet portion is manufactured.
In FIG. 6B, use is made of two magnets 127 and 128 secured to the
bed 112 in such a manner that adjacent poles are opposite in
polarity. As seen, however, these two magnets have different
widths, i.e. a greater width d.sub.1 for magnet 127 and a smaller
width d.sub.2 for magnet 128. The greater dimensions of the magnet
127 provide a greater density and intensity of the magnetic flux
M.sub.1 than the magnetic flux M.sub.2 provided by the smaller
magnet 128. Therefore, the magnetic flux at the midpoint between
both magnets does not become zero in spite of the cancelling effect
of both of the magnetic fluxes, and the magnetic flux from the
magnet 127 dominates that of the magnet 128 at the midpoint between
the magnets. However, the strength of the magnetic field in this
area between the magnets is insufficient to bring the contact
elements in the reed switch into contact with each other to close
the reed switch. In other words, the reed switch, in a normal
state, is subjected to reduced magnetic field caused by the
cancelling effect of both of the magnetic fluxes M.sub.1 and
M.sub.2.
When the key associated with the supporting plate 111 is depressed,
the reed switch is offered to the dominant magnetic flux M.sub.1
from the magnet 127, and then the reed switch is closed. As is
apparent from FIG. 6B, the reed switch encounters an abrupt change
in strength of magnetic field from an interacting region between
both of the magnets M.sub.1 and M.sub.2 to an operating region
governed by the magnet M.sub.1 exclusively, with the result that
the reed switch can be closed and opened by moving the magnet
structure over a short distance. In other words, the reed switch
may be operated with a smaller stroke of the key and without being
affected by noise.
As will be appreciated from the foregoing description, the key
apparatus of the present invention enables the reed switch to be
fixed perpendicularly to the direction of movement of the key,
whereby the height of the key apparatus may be greatly reduced.
FIG. 7 shows, in bottom plan vies, an example of the input key
board of a desk type electronic computer in which a number of such
key apparatuses are disposed closely adjacent to one another.
The key apparatuses are designated by numerals 41 to 49, of which
41-42-43, 44-45-46 and 47-48-49 form "rows" and 41-44-47, 42-45-48
and 43-46-49 form "columns". Those of such key apparatuses 41 to 49
which form any common column are arrayed in such a manner that the
magnetic portions thereof face in the same direction. More
specifically, the magnetic portions 41', 44' and 47' of the key
apparatuses 41, 44 and 47 face upward as viewed in FIG. 7, while
the magnetic portions 42', 45' and 48' of the key apparatuses 42,
45 and 48 face downward, and the magnetic portions 43', 46' and 49'
of the key apparatuses 43, 46 and 49 face upward. On the other
hand, those of the key apparatuses 41 to 49 which form any common
row are arrayed in such a manner that adjacent magnetic portions
face in opposite directions to each other. Thus, as shown, the
magnetic portions 41 and 43' face upward while the magnetic portion
42' faces downward, the magnetic portions 44' and 46' upward while
the magnetic portion 45' downward, and the magnetic portions 47'
and 49' upward while the magnetic portion 48' downward.
The described arrangement of the magnets of the key apparatuses
forming columns and rows enables reed switches 41" to 49" to be
effectively arranged so as to form a compact key board.
The same result as described above can also be attained by
arranging the key apparatuses 90.degree. out of phase with respect
to the arrangement of FIG. 7 and interchanging the columns and rows
with each other so that the magnetic portions in a certain column
face in the same direction while adjacent magnetic portions in a
certain row face opposite to each other.
* * * * *