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Claims  |
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I claim:
1. A multi-position electrical switch including in combination:
a housing having a bottom and a top, said top having an opening
therethrough;
at least two pairs of spaced-apart conductors located adjacent the bottom
of said housing, each pair of conductors located at a predetermine
distance from a point on said bottom;
an actuating member extending through an opening in said top, said
actuating member having a flange on the lower end thereof, said flange
extending radially outwardly from a central axis through said actuating
member, said opening in said top being aligned with said point on said
bottom, and said flange being of a greater diameter than the width of said
opening;
a deformable resilient support member having a circular opening in the
center thereof and having at least a portion thereof in contact with the
lower surface of said flange;
spherical bearing means located in the opening in said support member, said
bearing means engaging said point on the bottom of said housing and a
point at the center of the bottom of said flange of said actuating member;
at least two conductive contact means located on the bottom of said
deformable support member and positioned for bridging corresponding ones
of said pairs of spaced-apart conductors, whereupon when said actuating
member is tilted downwardly about said spherical bearing means toward a
selected one of said pairs of spaced-apart conductors, a corresponding one
of said contact means is pressed into contact to bridge the space between
such selected one of said pairs of conductors to complete an electrical
circuit therethrough so long as said actuating member remains tilted
downwardly, release of said actuating member allowing said deforable
resilient support member to return said actuating member to a rest
position where none of said conductive contact means are in electrical
contact with any of said spaced-apart pairs of conductors.
2. The combination according to claim 1 wherein said support member is made
of rubber-like material.
3. The combination according to claim 2 wherein said conductive contact
means are made of conductive rubber material.
4. The combination according to claim 3 wherein said conductive contact
means are circular disks having a diameter greater than the space between
the corresponding pairs of spaced-apart conductors.
5. The combination according to claim 3 wherein said spaced-apart
conductors comprise printed circuit conductive strips extending in
parallel pairs radially outwardly from said point on said bottom.
6. The combination according to claim 5 wherein said pairs of spaced-apart
conductors comprise four pairs of spaced-apart conductors each located at
ninety degree intervals in a circle, the center of which is said point on
said bottom.
7. The combination according to claim 6 wherein said spherical bearing
means comprises a ball bearing.
8. The combination according to claim 7 wherein said ball bearing is a
metal ball bearing, and said bottom of said housing and said actuating
member are made of plastic material.
9. The combination according to claim 7 wherein said actuating member has a
body portion in the form of a cylindrical section and said flange on the
lower end thereof is a circular flange having a diameter greater than the
diameter of said body portion of said actuating member.
10. The combination according to claim 9 wherein the top of said actuating
member is a concave surface.
11. The combination according to claim 10 wherein said deformable support
member is a circular support member having an outer flange, with an inner
portion spaced upwardly from the bottom edge of said outer flange, said
conductive contact means being attached to said inner portion on the
bottom side thereof and normally spaced above the corresponding pairs of
said conductors, with said actuating member in a rest position thereof.
12. The combination according to claim 11 wherein at least a portion of
said flange on said actuating member overlies said conductive contact
means, with said rest position of said actuating member provided by a
portion of the upper surface of said support member.
13. The combination according to claim 12 wherein a mating semi-spherical
concave depression is formed on the bottom of said actuating member at the
center thereof for engaging said spherical bearing means.
14. The combination according to claim 1 wherein said spherical bearing
means comprises a ball bearing.
15. The combination according to claim 14 wherein said ball bearing is a
metal ball bearing, and said bottom of said housing and said actuating
member are made of plastic material.
16. The combination according to claim 1 wherein said actuating member has
a body portion in the form of a cylindrical section and said flange on the
lower end thereof is a circular flange having a diameter greater than the
diameter of said body portion of said actuating member.
17. The combination according to claim 16 wherein the top of said actuating
member is a concave surface.
18. The combination according to claim 16 wherein said deformable support
member is a circular support member having an outer flange, with an inner
portion spaced upwardly from the bottom edge of said outer flange, said
conductive contact means being attached to said inner portion on the
bottom side thereof and normally spaced above the corresponding pairs of
said conductors, with said actuating member in a rest position thereof.
19. The combination according to claim 1 wherein at least a portion of said
flange on said actuating member overlies said conductive contact means,
with said rest position of said actuating member provided by a portion of
the upper surface of said support member.
20. The combination according to claim 1 wherein a mating semi-spherical
concave depression is formed on the bottom of said actuating member at the
center thereof for engaging said spherical bearing means.
21. The combination according to claim 1 wherein said pairs of spaced-apart
conductors comprise four pairs of spaced-apart conductors each located at
ninety degree intervals in a circle, the center of which is said point on
said bottom.
22. The combination according to claim 1 wherein said spaced-apart
conductors comprise printed circuit conductive strips extending in
parallel pairs radially outwardly from said point on said bottom.
23. The combination according to claim 1 wherein said deformable support
member is a circular support member having an outer flange, with an inner
portion spaced upwardly from the bottom edge of said outer flange, said
conductive contact means being attached to said inner portion on the
bottom side thereof and normally spaced above the corresponding pairs of
said conductors, with said actuating member in a rest position thereof.
24. The combination according to claim 1 wherein said conductive contact
means are made of conductive rubber material.
25. The combination according to claim 24 wherein said conductive contact
means are circular disks having a diameter greater than the space between
the corresponding pairs of spaced-apart conductors. |
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Claims |
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Description |
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BACKGROUND
Multiple position switches are used in many applications. For example,
multiple position switches, commonly referred to as joy stick switches,
are widely used for electronic games and the like. Such switches also are
found in the steering control devices for self propelled electric wheel
chairs. Computers frequently employ multiple position or multi-direction
switches for controlling the movement of a cursor on a computer display
screen.
Five patents which are specifically directed to multi-position or
multi-directional switch mechanisms are the U.S. Pat. Nos. to Chandler
4,246,452; Smith 4,408,103; Main 4,428,649; Nakayama 4,476,356; and Shirai
4,687,200. All of these patents disclose the use of a central actuating
lever of key which is pivoted or tipped about a central point to close
switch contacts located in a circle around this central point. The
operation of the mechanisms disclosed in all of these patents is
substantially the same. A resilient member of spring is used to return
each of the actuating levers of the switches of these patents to a rest or
neutral position. Separate metal springs are used for this purpose, with
the exception of the Shirai and Smith Patents which disclose the use of a
resilient circular elastomeric member to provide the return spring
function. In all of these patents, the pivot portion comprises either an
extension which is formed as an integral part of the switch actuating
lever, or is formed as an integral part of the base or bottom of the
housing in which the switch is located. It has been found that the plastic
projections forming the pivots in the devices disclosed in these patents
typically have a substantial amount of friction which reduces the
quickness of the response of the switch. In addition, when the switch
undergoes extensive use, significant wear frequently is encountered in the
pivot of such integrally molded parts.
It is desirable to provide a multi-position electrical switch which
incorporates the advantages of the prior art devices and which reduces
friction and wear.
SUMMARY OF THE INVENTION
Accordingly, it is an object of this invention to provide an improved
multi-position electrical switch.
It is another object of this invention to provide a compact, simple and
efficient multi-directional switch.
It is an additional object of this invention to provide an improved
multi-directional switch which requires minimum force to operate.
It is a further object of this invention to provide an improved
multi-position or multi-directional electrical switch which exhibits
reduced friction and reduced wear over periods of extensive use.
In accordance with a preferred embodiment of this invention, a
multi-position electrical switch is mounted in a housing having a bottom
and a top. Pairs of spaced-apart conductors are located on the bottom of
the housing, and each of the pairs of conductors are located a
predetermined distance from a point on the bottom of the housing. A
cylindrical actuating member extends upwardly through an opening in the
top of the housing. This actuating member has a flange on the lower end,
and the flange extends radially outwardly from the central axis through
the member. The opening in the top of the housing is aligned with the
point on the bottom; and a deformable, resilient support member, which has
a circular opening in its center, is located between the flange and the
bottom of the housing. A spherical bearing is located in the opening in
the support member, and this bearing engages the point on the bottom of
the housing and a corresponding point at the center of the bottom of the
flange of the actuating member. Conductive contacts are located on the
bottom of the deformable support member, and each contact is positioned to
bridge corresponding ones of the pairs of the spaced-apart conductors.
When the actuating member is tilted downwardly about the spherical bearing
toward a selected one of the pairs of conductors, the corresponding
contact engages the pair of conductors to complete an electric circuit.
When the actuating member is released, the resilient support member
returns the actuating member to a neutral or rest position where none of
the conductive contacts are in electrical contact with any of the pairs of
conductors.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a partially cut-away top perspective view of a preferred
embodiment of the invention;
FIG. 2 is a cross-sectional view taken along the line 2--2 of FIG. 1;
FIG. 3 is a cross-sectional view taken along the same line as FIG. 2, but
illustrating a different position of operation of the device;
FIG. 4 is an exploded view of the preferred embodiment of the invention
shown in FIG. 1; and
FIG. 5 is a top view of a portion of the embodiment shown in FIGS. 1 though
4.
DETAILED DESCRIPTION
Reference now should be made to the drawings in which the same reference
numbers are used through the different figures to designate the same
components. FIG. 1 is a perspective view of a preferred embodiment of a
multi-position electrical switch which may be used for a variety of
different applications. Such switches typically are housed in relatively
compact plastic housings. Since the configuration of the housing may vary
considerably, depending upon the device with which the switch is used,
only a portion of such a housing 10, in the form of a small part of a top
11 and a bottom 12 is illustrated in FIG. 1. Obviously, sides and ends
(not shown) are employed to enclose the housing and to space the top 11
and the bottom 12 from one another. At the location where the
multi-position switch is to be located, a circular opening 15 is formed in
the top 11. This opening is shown most clearly in FIGS. 1, 2 and 3.
The actuator for the switch mechanism comprises a cylindrical plastic
pushbutton 23 with a concave top 24. The outer diameter of the pushbutton
or actuator 23 is less than the diameter of the opening 15 to permit the
actuator 23 to extend upwardly through the opening 15. The difference in
diameters also is selected to provide clearance to permit the actuator 23
to be rocked or tilted in any direction in the opening 15, as indicated
generally by the arrows in FIG. 2. The bottom of the actuator 23 has an
integrally formed, circular flange 26 attached to it. The diameter of the
flange 26 is greater than the diameter of the opening 15 in the top 11 to
captivate the actuator 23 in the housing 10 when the unit is assembled
together.
As illustrated most clearly in FIG. 5, the base 12 has four (4) pairs of
conductive metal strips 16, 17, 19, and 20, located on it at 90.degree.
intervals about a central point which is aligned with the central axis of
the actuator 23. These pairs of conductive strips 16, 17, 19, and 20,
preferably are in the form of integrated circuit conductors which are
interconnected with other circuit elements (not shown) for effecting the
desired function to be accomplished by completing or closing an electrical
circuit between the two conductors of each pair. It is apparent from an
examination of FIGS. 4 and 5, that without some type of contact bridging
the ends of the pairs of conductors 16, 17, 19, and 20, they represent an
open circuit or open switch.
A deformable resilient support member 30 is placed between the bottom of
the flange 26 and the top surface of the housing bottom 12 to support the
actuator 23 and to cause it to extend through the circular opening 15 in
the top 11 of the housing. This resilient support member preferably is
made of rubber or other suitable elastomeric material, and is sufficiently
rigid to support the actuator 23 in a rest or neutral position, as
illustrated most clearly in FIG. 2.
The member 30 has an outer circular flange 31 on it which supports an
intermediate web 32 comprising a circular disk integrally formed with the
flange 31. Spaced from the inner edge of the flange 31 is an upwardly
extending circular rim 34, the top of which engages the underside of the
flange 26 on the actuator member 23. The center of the support member 30
has a circular opening 36 in it (shown most clearly in FIG. 4), and a
spherical ball or ball bearing 50 is located in this opening 36.
Preferably the ball 50 is made of stainless steel or other suitable
material. As most clearly shown in FIGS. 2 and 3, the ball bearing 50
engages a mating concave depression 51 in the bottom of the actuator 23
and rests on the central point on the bottom of the housing located in the
center of the ends of the contact pairs 16, 17, 19, and 20.
Located directly above each of the ends of the contact pairs 16, 17, 19,
and 20 are mating circular conductive rubber contact disks 40, which are
attached to the underside of the web portion 32 of the deformable
resilient support member 30. The location of these disks is most clearly
shown in FIGS. 4 and 5, although two of them, conductive disks 40 and 41,
also are shown above the respective contact pairs 19 and 16 in FIGS. 2 and
3. Additional disks 43 and 44 are located in alignment with the contact
pairs 17 and 20, respectively, as shown in FIGS. 4 and 5. The disks 40,
41, 43, and 44 are bonded to or are secured to the underside of the web
portion 32 of the deformable support member in any suitable manner. The
remainder of the parts forming the pushbutton switch are not permanently
interconnected, but are held in place by the configuration of the housing
10, so that assembly and disassembly simply is effected by stacking and
unstacking the parts in accordance with the illustration show in FIG. 4.
In operation, the switch is held at a rest or neutral, unoperated position
by the resilient support member 30 which returns to its "memory" position,
as shown in FIG. 2, to space all of the conductive rubber contact disks
40, 41, 43 and 44 above and out of contact with the respective pairs of
conductors 16, 17, 19, and 20. This is illustrated in FIG. 2. To operate
the switch, a person simply places a finger in the concave depression 24
on the top of the actuator 23 and pushes the actuator in the desired
direction to close the desired circuit between the corresponding pairs of
conductors to perform an associated circuit operation. Because the ball
bearing 50 is rigid and essentially friction free, the force required to
tip the actuator 23 is dependent only upon the resiliency of the
deformable support member 30.
When the device is operated to tip the actuator 23 toward the right, as
viewed in FIGS. 2 and 3, the resilient support member 30 is deformed to
the position shown in FIG. 3. This causes the conductive rubber contact
disk 41 to press against the upper surface of the two conductors forming
the conductor pair 16 to make an electrical connection from one conductor
of the pair to the other through the contact disk 41. The manner in which
this is done is illustrated in FIGS. 3 and 5. In FIG. 5, the shading on
the ends of the conductor pair 16 made by the contact disk 41 is
indicative of electrical contact being made between the two conductors of
the pair 16. None of the other conductive disks 40, 43 or 44 make
connection in this position, since the resilient support member 30
continues to hold these disks out of engagement with the conductors with
which they are associated. Tipping or tilting of the actuator 23 in any of
the other directions indicated in FIG. 2 closes a corresponding circuit
between the ends of the associated conductors located in the direction in
which the actuator 23 is tilted. Although four sets of conductor pairs
located at 90.degree. spacings in a circle about the central pivot point
of the ball bearing 50 are illustrated, more or less conductor pairs may
be used in accordance with the particular application which is intended
for the multi-position switch mechanism. Four (4) directions, however, are
relatively common and constitute a popular configuration for such a
switch.
The stainless steel ball bearing 50 significantly reduces friction over
plastic projections or fulcrums of the type which have been used
previously. Since the friction is reduced, wear and potential mechanical
failure also is reduced. The ball bearing 50 evenly distributes pressures
applied to the top 24 of the actuator 23 during operation. Since friction
is reduced by the ball bearing or spherical ball support 50, a livelier
operating action requiring less force is achieved. Consequently, the
switch may be activiated with less force or finger pressure to make it
particularly suitable for hand held devices. In addition, the device is
potentially easier to use by persons with restricted hand movement and
strength. This latter advantage is particularly important, for example,
when the device is used for a control system for a self-propelled wheel
chair or for a bedside signaling device for hospital patients.
Various changes and modifications will occur to those skilled in the art
without departing from the true scope of the claims. For example, the
actuator 23, with its associated flange 26 is described as being plastic,
but it could be made of metal as well, if desired. Other materials may be
found suitable. In addition, the particular configuration of the
deformable resilient support member is to be considered illustrative only
since the function of this member may be attained with other
cross-sectional shapes, for example. The contact disks have been described
as being made of conductive rubber, but metal disks could be used as well
without in any way departing from the true scope of the invention. Other
changes and modifications also will occur to those skilled in the art
without departing from the true scope of the invention, as defined in the
appended claims.
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Description |
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