U.S. patent number 3,918,021 [Application Number 05/480,230] was granted by the patent office on 1975-11-04 for device for simultaneously controlling a plurality of variable resistors.
This patent grant is currently assigned to Matsushita Electric Industrial Company, Limited. Invention is credited to Matsuo Nishioka, Shunzo Oka.
United States Patent |
3,918,021 |
Nishioka , et al. |
November 4, 1975 |
Device for simultaneously controlling a plurality of variable
resistors
Abstract
A bearing having spherical bearing surface is attached to an
opening formed at the center of the top wall of a casing. The
bearing rotatably receives a spherical body having a control shaft
which extends through the center of the spherical body and is
securely fixed thereto. A plurality of outer resistors is arranged
on the bottom wall of the casing in a frame-like form and a
plurality of arcuate shaped inner resistors is circularly arranged
inside of the outer resistors. A pair of intersecting slidable
members each having an elongated guide slot and an outer contactor
at the opposite ends thereof is slidably movable in the casing with
the contactors being in slidable engagement with the corresponding
outer resistors. A rotary disc having a plurality of inner
contactors equal in number to the inner resistors is rotatably
supported on the bottom wall of the casing. The lower end of the
control shaft slidably extends through the guide slots of the
intersecting members. A universal joint operatively couples the
lower end of the control shaft to the rotary disc. As the control
shaft is inclined in any direction to any tilt angle, the point of
contact on each of the two or four outer resistors may be
simultaneously controlled in desired proportions. As the control
shaft is rotated about its axis with the control shaft being held
in the same tilted position, the point of contact on each of the
inner resistors may be simultaneously controlled in an equal
proportion.
Inventors: |
Nishioka; Matsuo (Kadoma,
JA), Oka; Shunzo (Kadoma, JA) |
Assignee: |
Matsushita Electric Industrial
Company, Limited (JA)
|
Family
ID: |
23907175 |
Appl.
No.: |
05/480,230 |
Filed: |
June 17, 1974 |
Current U.S.
Class: |
338/128; 200/6A;
338/127; 74/471XY; 273/148B |
Current CPC
Class: |
G05G
9/047 (20130101); G05G 2009/04707 (20130101); G05G
2009/04751 (20130101); Y10T 74/20201 (20150115) |
Current International
Class: |
G05G
9/047 (20060101); G05G 9/00 (20060101); H01C
009/02 () |
Field of
Search: |
;338/90,127,128,129,130,131,132 ;74/471XY ;200/6A ;323/80
;340/384R,366D ;403/383 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Mayewsky; Volodymyr Y.
Attorney, Agent or Firm: Burns; Robert E. Lobato; Emmanuel
J. Adams; Bruce L.
Claims
What is claimed is:
1. In a device for simultaneously controlling a plurality of
variable resistors, including a casing having a pair of opposed
insulating members, a control shaft pivotally supported by and
extending through one of said opposed members, a pair of
intersecting slide members each having an elongated guide slot and
being slidably movable mutually perpendicularly to each other, one
end of said control shaft slidably extending through the guide
slots of said intersecting slide members, the improvement in
combination therewith which comprises an insulating rotary member
rotatably supported on the other member of said casing at a
predetermined spacing therefrom, a universal joint coupling the
axis of said rotary member with said one end of said control shaft,
said variable resistors including a plurality of elongated outer
resistive elements in a rectangular frame-like form on the said
other member and a plurality of first electrical contact elements
equal in number to said outer resistive elements at the opposite
ends of each of said intersecting slide members and in slidable
electrical contact with the corresponding outer resistive element,
and a plurality of inner arcuate shaped resistive elements
circularly arranged on the said other member in opposed relation to
said rotary member and a plurality of second electrical contact
elements equal in number to said inner resistive elements and
carried by said rotary member in slidable electrical contact with
the corresponding inner arcuate shaped resistive element, said
outer resistive elements being electrically interconnected to each
other, and each of said outer resistive elements being electrically
connected to respective ones of said inner resistive elements.
2. The improvement as claimed in claim 1, wherein each of said
outer resistive elements is further connected to an external
terminal.
3. The improvement as claimed in claim 1, wherein said outer and
inner resistive elements are connected conductively.
4. The improvement as claimed in claim 1, wherein said first and
second electrical contact elements are connected to a further
external terminal.
5. The improvement as claimed in claim 1, wherein each of said
intersecting elongated member has at each end thereof a side member
of a predetermined weight slidably in contact with said one of the
opposed walls and slidably movable on said outer resistive
element.
6. The improvement as claimed in claim 1, further comprising a
rectangular frame-like conductive element adjacent said outer
resistive elements, said first electrical contact element providing
electrical connection between said conductive element and the
corresponding outer resistive element.
7. The improvement as claimed in claim 5, further comprising an
annular conductive element adjacent said inner resistive elements,
said second electrical contact element providing electrical
connection between said annular conductive element and the
corresponding inner resistive element.
8. The improvement as claimed in claim 5, wherein said rectangular
frame-like conductive element are connected to a common
terminal.
9. The improvement as claimed in claim 1, wherein said universal
joint comprises an input shaft having a polygonal cross-section and
an output shaft having a polygonal cross-section, said input shaft
being rotatably coupled through a first spider to the lower end of
said control shaft and axially slidably extending into said output
shaft, said output shaft being rotatably coupled through a second
spider to said rotary disc.
Description
The present invention relates generally to variable resistors, and
particularly to a device for simultaneously controlling a plurality
of variable resistors.
In a prior art device, a bearing having a spherical bearing surface
is attached to an opening formed at the center of the top wall of a
casing having side walls. The bearing rotatably receives a
spherical body having a control shaft which extends through the
center of the spherical body and is securely fixed thereto.
Variable resistors of the conventional type are attached to the
side walls of the casing in such a manner that their rotary shafts
may extend into the casing. Each of the opposed pairs of the
variable resistors are interconnected with a bow-shaped elastic
connecting member having an axially elongated slot. The lower end
of the control shaft is fitted into the axially elongated slots of
the connecting members which intersect each other, but do not
interfere with each other.
Although the prior art device is useful for applications such as a
four-channel phonograph to provide balance control between sound
outputs of the respective sound channels, a separate volume control
device is needed to control the absolute levels of the sound
outputs irrespective of the balance control.
Therefore, the principal object of the invention is to provide an
improved device for simultaneously controlling a plurality of
variable resistors wherein simultaneous variation in resistance
values relative to each other is effected in combination with
simultaneous variation in the absolute resistance values without
affecting the resistance values relative to each other.
Another object of the invention is to provide an improved device
for simultaneously controlling a plurality of variable resistors
wherein the variable resistors are arranged in a manner that
permits the resistors to be constructed from a single sheet of
resistive material.
A further object of the invention is to provide an improved device
for controlling a plurality of variable resistors wherein overall
size of the device is kept to a minimum.
A still another object is to provide an improved device for
simultaneously controlling a plurality of variable resistors
wherein the production cost is minimized.
A still further object of the invention is to provide a uniaxial
balance and volume control device to facilitate control in the
magnitude of the respective sound channels.
Briefly described, the device in accordance with the invention has
a casing having a pair of opposing walls. An opening is provided in
one of the opposing walls in which a bearing having a spherical
inner surface is attached. The bearing rotatably receives a
spherical body having a control shaft which extends through the
center of the spherical body and is securely fixed thereto. A
plurality of outer resistors in strip-like form is arranged on the
other wall of the casing in the outer periphery thereof in
generally frame-like configuration. A plurality of circularly
arranged inner resistors in arcuate form is also arranged on the
other wall. A pair of intersecting slidable members each having an
elongated guide slot is slidably movable in the casing transversely
to the axis thereof and longitudinally to each other. Each of the
intersecting members has an outer contactor at the opposite ends
thereof which is slidably kept in electrical contact with the outer
resistors. One end of the control shaft slidably extends through
the guide slots of the intersecting members whereby pivotal
movement of the control shaft permits each of the intersecting
members to slide transversely to the axis thereof and
longitudinally to each other. A rotary disc having a plurality of
inner contactors equal in number to the inner resistors is
rotatably supported on the other wall of the casing, with the
contactors being in slidable contact with the inner resistors. A
universal joint is provided to operatively couple the rotary disc
with the one end of the control shaft. Rotation of the control
shaft about the axis thereof causes the rotary disc to rotate so
that the contactors slide in engagement with the corresponding
inner resistors.
When the control shaft is inclined to a given tilt angle in any
direction, the outer contactors slide in engagement with the
corresponding outer resistors in accordance with the angle and
direction of the tilted control shaft so that the point of contact
on each of the two or four outer resistors is simultaneously
controlled in desired proportions. As the control shaft is rotated
about its axis with the control shaft being held at the same
position, the point of contact on each of the inner resistors will
be simultaneously controlled in an equal porportion.
These and other features of the present invention will become
apparent as the following description proceeds when taken in
conjunction with the accompanying drawings, in which:
FIG. 1 is a cross-sectional view in elevation of a device in
accordance with the invention;
FIG. 2 is a plan view of the device with the top wall of a casing
being removed;
FIG. 3 is a plan view of the device with a pair of intersecting
slidable members being removed to show a plurality of resistors
arranged on the bottom wall of the casing;
FIG. 4 is a plan view of a plurality of resistors constructed from
a single sheet of resistive material;
FIG. 5 is an equivalent circuit of the resistors employed in the
present invention; and
FIG. 6 is an enlarged perspective view of a universal joint
employed in the device of the present invention.
Referring to FIGS. 1-5, a preferred embodiment of the invention
will be described. A box-like casing 1 has a top wall and opening 2
therein to which are attached with rivets 3 upper and lower
bearings 4 and 5 which are made of a synthetic resin by molding and
which have spherical inner surfaces. A spherical body 6 having a
control shaft 7 extending axially through the center thereof is
pivotally received in these bearings 4 and 5. Ears 12 of the casing
1 is folded back in order to securely attach the bottom wall to the
casing. The casing 1 has on the bottom wall an opening 8 to which
is attached a bearing 9. A rotary shaft 10 is rotatably received
into the bearing 9 and has a knob 11 at the lower end thereof. A
disc 13 of a non-conducting material has an opening at the center
thereof in which the upper end of the rotary shaft 10 is securely
fitted. On the bottom wall of the casing 1 there is arranged a
plurality of outer resistive elements 14 to 17 along the peripheral
edges of the bottom wall in a generally rectangular frame-like form
and a plurality of inner resistive elements 18 to 21 or arcuate
shape circularly arranged inside of the frame-like configuration
formed by the outer resistive elements, as best shown in FIG. 3.
The outer resistive elements 14 to 17 are interconnected by means
of conductive elements 22 to 25 which have legs 22a, 23a, 24a, and
25a formed integrally therewith and extending inwardly to one end
of associated inner resistive elements 18 to 21, respectively. It
is seen that outer resistive elements 14 to 17 are connected in
parallel to the inner resistive elements 18 and 21, respectively. A
conductive ring 26 is disposed inside of an area defined by the
inner resistive elements 18 to 21 on the bottom wall of the casing
1. An outer conductive framelike element 27 is disposed on the
bottom wall of the casing 1 around the outer periphery of the outer
resistive elements 14 to 17 with each of the side members being
parallel thereto.
A slidable elongated member 28 having an elongated guide slot 28a,
downwardly flared portions 28b, 28c and upwardly flared portions
28d is provided in the casing 1. Each of the downwardly flared
portions 28b, 28c has a pair of interconnected contactors such as
brushes 30, 31 and a pair of interconnected contactors 32, 33 on
the lower surface thereof which make slidable electrical contact
with outer resistive element 15, outer conductive element 27, outer
resistive element 17 and outer conductive element 27, respectively.
Another slidable elongated member 29 having an elongated guide slot
29a, downwardly flared portions 29b, 29c and upwardly flared
portions 29d is provided in the casing in such a manner that it
intersects the slidable member 28 preferably at right angles.
Similarly, each of the downwardly flared portions 29b, 29c has a
pair of interconnected contactors (not shown) on the lower surface
thereof which make slidable electrical contact with outer resistive
element 14, outer conductive element 27, outer resistive element 16
and outer conductive element 27, respectively. The intersecting
slidable members 28 and 29 have stepped shoulder portions 28e and
29e respectively along the edge of the respective guide slots 28a
and 29a.
An interlocking element 34 of a disc configuration having a pair of
inwardly cutaway portions 34a on the opposite sides thereof and an
aperture 34b along the axis thereof is slidably received in the
guide slots 28a and 29a of the intersecting members 28 and 29. The
lower end of the control shaft 7 slidably extends through the
aperture 34b of the interlocking element 34.
In accordance with the present invention there is provided a
universal joint 35 which comprises an input shaft 35a rotatably
coupled by means of spider 35e to a bracket 35e fixed to the lower
end of the control shaft 7 and an output shaft 35b rotatably
coupled by means of spider 35f to a bracket 35d fixed to the rotary
disc 13 (FIG. 6). The input shaft 35a has a rectangular or
polygonal cross-section and axially slidably extends into the
interior of the output shaft 35b of a rectangular or polygonal
cross-section. This arrangement permits the control shaft 7 to
cause sliding movements of the slide members 28 and 29 without
effecting rotary movement of the rotary disc 13, while permitting
control of the latter without effecting the sliding movements of
the former. The rotary disc 13 has on its lower surface four pairs
of equally spaced, radially arranged interconnected contactors 36
and 37 to make slidable electrical contact with the inner resistive
element 19 (20, 21, 18) and the inner conductive element 26. As
best shown in FIG. 5, the outer and inner resistive elements are
electrically interconnected. Resistors 15 and 19 are connected in
parallel to each other to a common terminal 36 through contactors
30 and 31, outer conductive element 27 to which inner conductive
element 26 is connected electrically by suitable means, and through
contactors 36 and 37, the common terminal being connected to the
inner conductive element 26. Similarly, the rest of the outer and
inner resistive element is connected in the same manner as
described above. A plurality of terminals 14a, 15a, 16a, and 17a is
provided at each corner of the frame-like resistive elements 14 to
17 to provide connection to external circuitry associated with the
respective sound channels with the terminal 36 being common to the
external circuit.
When the control shaft 7 is inclined pivotally to a given angle in
any direction, the interlocking element 34 will evidently slide
along the guide slots 28a and 29a of the respective slidable
members 28 and 29. Therefore, the slidable members 28 and 29 are
caused to move transversely to the axis thereof and longitudinally
to each other. It is appreciated that the intersecting slidable
members 28 and 29 singly or simultaneously move in directions
perpendicular to each other in accordance with the direction of the
control shaft 7 so that the four interconnected pairs of contactors
provided on the lower surface of the downwardly flared portions
28b, 28c, 29b, 29c, may follow straight paths in slidable contact
with the outer resistive elements 14 to 17 as well as the outer
conductive element 27. The simultaneous control of the resistance
values of outer resistors 14 to 17 in different proportions is thus
effected, with the variation in resistance being dependent upon the
tilt angle of the control shaft. The upwardly flared portions 28d
and 29d of the slidable members 28 and 29 are in slidable contact
with the top wall of the casing 1 so that the slidable members may
slide on a two-dimensional plane parallel to the top wall of the
casing. The downwardly flared portions 29b, 28c, 29b, and 29c have
preferably a predetermined weight in order to provide an
inertia-producing effect for smooth movement of the intersecting
members 28 and 29.
With the control shaft 7 being held at a given tilt angle in a
given direction, the control shaft is rotated about its axis. The
rotation of the control shaft is transmitted through the universal
joint 35 to the rotary disc 13 so that the four interconnected
pairs of contactors on the lower surface thereof may follow a
circular path in contact with the inner resistive elements 18 to 21
as well as the inner conductive element 26. This provides
simultaneous variation of the magnitude of the inner resistive
elements 18 to 21 in an equal proportion while keeping the outer
resistive elements 14 to 17 at the given magnitude of resistance
determined by the angle and direction of the tilted control shaft.
It is appreciated that the outer resistances are only varied in
their magnitudes by the direction and tilt angle of the control
shaft 7 while the inner resistances are only varied in their
magnitudes by the rotation of the control shaft 7 about the axis
thereof.
The arrangement as described above is particularly useful for
applications such as four-channel stereophonic recording or
playback apparatus. The outer resistances thus arranged serve to
provide balance control between the respective sound channels
wherein the sound levels of the channels are varied simultaneously
relative to each other while the inner resistance serve to control
the absolute sound levels of the separate channels in an equal
proportion.
Since the outer resistors are parallel-connected with associated
inner resistors, the variation in the resistance values of the
inner resistors, and vice versa, effectively varies the resultant
resistance values of the parallel-connected outer and inner
resistors. This allows reduction in the number of terminals
required for connection to external circuits.
Although the resistive elements may be separated from each other
for individual connections to external circuits, this will be
disadvantageous from the production standpoint. This invention thus
permits the outer and inner resistive elements to be constructed
from a single sheet of resistive material, for example, by punching
it out into a shape, as illustrated in FIG. 4, having a generally
rectangular frame-like outer portion, circularly spaced arcuate
shaped inner portions and four legs extending from each corner of
the frame-like portion inwardly to each of the arcuate shaped
portions. The four legs are covered with the conductive elements 22
to 25. The resistive elements are thus produced in a manner that
tends to reduce the production cost and the overall size of the
device.
* * * * *