U.S. patent number 3,902,120 [Application Number 05/471,817] was granted by the patent office on 1975-08-26 for combination radio receiver and stereo headphones.
This patent grant is currently assigned to Dyn Electronics, Inc.. Invention is credited to Charles Dascal, Jack De Laster.
United States Patent |
3,902,120 |
Dascal , et al. |
August 26, 1975 |
Combination radio receiver and stereo headphones
Abstract
A set of stereo headphones contains a radio receiver, having an
audio output circuit which drives speakers of the headphones.
During operation of the receiver, the speakers are connected in
series to provide a monaural sound reproduction of a received radio
signal. A stereo input jack, adapted to mate with a stereo plug, is
mounted directly to the headphones to receive a stereo signal
having right and left channel components applied from an external
stereo signal source through the plug. When the stereo plug is
mated with the input jack, a switch mounted to the jack is actuated
to disconnect the two speakers from the audio output circuit of the
receiver and connect the same to the terminals of the input jack to
provide sound reproduction of the right and left channel components
of the stereo signal. An ornamental cover is provided to enclose a
battery mounted in the headphones. The cover is secured to the
headphones with a manually operable latch mechanism permitting the
cover to be easily removed for replacement of the battery.
Inventors: |
Dascal; Charles (Miami, FL),
De Laster; Jack (Miami, FL) |
Assignee: |
Dyn Electronics, Inc. (Miami,
FL)
|
Family
ID: |
23873106 |
Appl.
No.: |
05/471,817 |
Filed: |
May 20, 1974 |
Current U.S.
Class: |
381/309; 381/74;
381/384; 455/351; 455/343.1; 200/51.09; D14/205 |
Current CPC
Class: |
H04B
1/16 (20130101); H04B 1/088 (20130101); H04R
1/1025 (20130101); H04R 5/033 (20130101); H04R
1/1041 (20130101); H04R 1/1008 (20130101) |
Current International
Class: |
H04B
1/08 (20060101); H04B 1/16 (20060101); H04B
001/08 () |
Field of
Search: |
;325/16,36,310,361
;179/1G,1GA,15BT,1PC,156R,182R,182A ;200/51R,51.09 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Griffin; Robert L.
Assistant Examiner: Bookbinder; Marc E.
Attorney, Agent or Firm: Lowe, King & Price
Claims
What is claimed is:
1. An entertainment unit including a set of headphones
alternatively responsive to a monaural signal source and a stereo
signal source, there being means connectable to the set of
headphones for supplying a stereo signal from the stereo source to
the headphones, comprising:
first and second speakers contained in said set of headphones;
said monaural signal source comprising a monaural radio receiver
contained in said set of headphones for providing a monaural audio
signal;
stereo signal input means mounted to said set of headphones for
receiving a stereo signal from said source external to said set of
headphones, said stereo signal having first and second channel
signal components; and
switching means actuated by said means for supplying the stereo
signal, said switching means mounted to said set of headphones and
connected to each of said speakers, said input means and said
receiver for selectively connecting either (a) both said speakers
to be driven by said monaural audio signal to provide a monaural
sound reproduction of a signal received by said receiver or (b)
said first and second speakers to be respectively driven by the
first and second channel components to provide a stereo sound
reproduction of said stereo signal.
2. The unit of claim 1 wherein said stereo signal input means
includes a stereo jack for receiving a stereo plug and said
switching means includes an electrical switch mounted to said jack,
said switch including means for changing the speaker connections to
selectively provide connections for (a) or (b) in response to said
stereo plug being inserted into and withdrawn from the jack.
3. The unit of claim 2 wherein the set of headphones includes means
for carrying a battery, said receiver including d.c. power supply
terminals connectable to terminals of the battery while connection
(a) is established and means for disconnecting the receiver from
one of the power supply terminals in response to the plug being
inserted into the jack.
4. The unit of claim 1 wherein the set of headphones includes means
for carrying a battery, said receiver including d.c. power supply
terminals, means for connecting the power supply terminals to
terminals of the battery while connection (a) is established, and
means for disconnecting one of the receiver power supply terminals
from the battery terminals while connection (b) is established.
5. The unit of claim 1 wherein one of said headphones includes an
outer surface having a cavity formed therein for receiving a
battery for powering said receiver; and a cover for at least
partially covering said outer surface.
6. The unit of claim 5 further including latching means for
selectively securing said cover to said one headphone and releasing
said cover to expose said battery in said cavity.
7. The unit of claim 6 wherein said latching means includes a
rotatable lug mounted to said cover, and said outer surface
includes a receiving slot, said lug and slot being relatively
positioned for mutual engagement.
8. An entertainment unit comprising in combination:
a set of headphones including first and second speakers;
a radio receiver contained in said set of headphones for driving
said speakers, one of said headphones having an outer surface with
a cavity formed therein for receiving a battery for powering the
receiver;
a cover for at least partially enclosing said outer surface of said
one headphone; and
latching means for releasably securing said cover to said one
headphone, wherein said latching means includes a lug mounted to
said cover, and said outer surface includes an aperture, said lug
and aperture being relatively positioned for mutual engagement,
said lug being selectively engageable and disengageable with said
aperture; and
spacing means for maintaining a portion of said cover spaced apart
a predetermined distance from said outer surface outside of said
one headphone when said lug is engaged with said aperture.
9. The entertainment unit of claim 8 further including an arm
secured to said lug for rotation therewith and accessible
externally of said cover, said latching means being operable with
said arm.
10. The entertainment unit of claim 8 further including a stand-off
disposed between said lug and said cover, and a rim formed in said
aperture for supporting said stand-off, whereby said cover and said
outer surface of said headphone are spaced apart.
11. The entertainment unit of claim 8 wherein said cover includes
at least one projection extending toward the cavity for maintaining
said battery within said cavity.
12. The entertainment unit of claim 11 further including a cushion
disposed within said cavity for cushioning the battery, a space
being provided between said projection and said cushion for
receiving the battery.
13. The entertainment unit of claim 8 wherein said spacing means
includes an island formed on said outer surface, said aperture
being formed in said island to receive said lug.
14. An entertainment unit including a set of headphones
alternatively responsive to an internal signal source and an
external stereo signal source, there being means connectable to the
set of headphones for supplying a stereo signal from the external
stereo signal source to the headphones, comprising:
first and second speakers contained in said set of headphones;
said internal signal source comprising a radio receiver contained
in said set of headphones for providing an audio signal;
stereo signal input means mounted to said set of headphones for
receiving a stereo signal from said source external to said set of
headphones, via said connectable means said stereo signal having
first and second channel signal components;
switching means actuated by said means for supplying the stereo
signal, said switching means mounted to said set of headphones and
connected to each of said speakers, said input means and said
receiver for selectively connecting said speakers to be driven by
either (a) the audio signal generated by said radio receiver or (b)
the stereo signal generated by said external stereo signal
source;
said set of headphones including means for carrying a battery for
powering said radio receiver, said receiver including d.c. power
supply terminals; and
said switching means further connecting the power supply terminals
to terminals of the battery while connection (a) is established,
and disconnecting one of the power supply terminals from the
battery terminals while connection (b) is established.
Description
FIELD OF THE INVENTION
The present invention relates generally to a combination battery
powered radio receiver and stereo headphone unit and more
particularly to the combination including a novel switch means for
automatically converting the unit between operation with the
receiver and operation with an external source of stereo signals,
and means for providing easy replacement of the battery.
BACKGROUND OF THE INVENTION
In stereophonic reproduction, two channels, i.e., right and left,
contain audio signal components which are amplified to drive right
and left speakers, respectively, to produce a "three-dimensional"
sound effect. The stereo signals are generally derived either from
a recording medium, such as a magnetic tape or vinyl recording, or
from a stereo broadcast signal received in a radio receiver
designed for stereo signal reception.
While large speakers are still probably the most commonly used
sound reproducers incorporated in a typical stereo system, stereo
headphones are becoming increasingly popular for several reasons.
Because the coupling of sound between the headphone speakers and
the ears of the user is far superior to that achieved in floor or
bookshelf speakers, the quality of sound reproduction is generally
quite good and a relatively inexpensive set of headphones often
compares in sound reproduction quality to that of an expensive set
of speakers. Also, because stereo headphones are applied directly
to the ears of the user, the reproduced stereo sound is not
generally affected by the acoustic properties of the room
containing the stereo equipment, a relatively important factor
which must be considered when conventional speakers are used. In
addition, because external noises are substantially blocked by the
acoustic seal between the headphones and the ears, the user can
listen to the stereo sound without being disturbed by environmental
noises and because the stereo sound is confined to the ears of the
user, other persons in proximity to the user are not disturbed.
With the advent of the transistor, radio receivers are now produced
which are extremely compact and efficient. A typical portable
transistorized radio receiver is generally powered by a battery
contained inside a case of the receiver and provides an audio
output from a small speaker contained within the case. In order to
confine the audio output of the receiver to the ears of the user, a
small earphone is often provided as an accessory with the receiver.
However, the earphone is inconvenient to use and lacks the high
quality of sound reproduction and acoustic isolation usually found
in a set of stereo headphones.
In order to combine the portability of a portable radio receiver
with the high quality sound reproduction and acoustic isolation
qualities of a set of stereo headphones, it has been heretofore
proposed to provide a unit including one of a monaural or a stereo
radio receiver directly inside the headphones. The audio output
circuit of the radio receiver is connected to the speakers of the
headphones and a battery contained within the headphones is used as
a source of power for the receiver. The units having speakers
responsive to a monaural receiver are connected either in parallel
or series to provide a monaural sound reproduction of the broadcast
material, while speakers of the units including a stereo receiver
are separately driven by the two stereo channels. There is no
presently existing headphone receiver unit capable of both
internally generated monaural and remotely generated stereo signal
operation.
While the above described arrangement performs generally
satisfactorily, it has the disadvantage of confining the use of the
headphone set to operation with the monaural or stereo radio
receiver contained therein. Often, the headphone used in
conjunction with the built-in receiver is itself suitable for
application in a stereo system; however, no convenient means has
been heretofore provided for selectively converting the headphones
for operation with an existing stereo system.
Another disadvantage of the combined headphone and receiver unit of
the prior art is that defective battery replacement requires the
cumbersome and inconvenient removal of a cover portion of the
headphones, generally by using a tool to remove at least one screw
from the cover. Frequently batteries become defective when the user
is away from home and an appropriate tool is often not immediately
available.
OBJECTS AND BRIEF DESCRIPTION OF THE INVENTION
Accordingly, it is one object of the present invention to provide a
new and improved combination stereo headphone and radio receiver
unit.
It is another object of the present invention to provide a new and
improved combination stereo headphone and radio receiver unit for
selectively reproducing a received radio signal or a stereo signal
generated from an external source.
It is yet another object of the present invention to provide an
entertainment apparatus which economically combines the portability
of a radio wave receiver with the high quality audio reproduction
of a set of stereo headphones.
It is an additional object of the present invention to provide a
new and improved combination stereo headphone and monaural radio
receiver unit which is automatically switched from one
configuration to the other merely by inserting or removing a stereo
plug into or out of a stereo input jack mounted to the unit.
It is a further object of the present invention to provide a new
and improved combination stereo headphone and radio receiver unit
having a battery cover which is easily removed.
In accordance with one preferred embodiment of the present
invention, a combined stereo headphone and monaural radio receiver
unit is provided having a receptacle and a switch mounted to the
unit for enabling the headphone to be automatically switched from a
monaural configuration responsive to the receiver to a stereo
configuration responsive to a remote stereo source coupled through
a jack included in the receptacle. A battery for powering the
receiver is contained in the headphone and enclosed by an
ornamental cover which is easily removed.
During operation of the unit with the radio receiver, the two
speakers of the headphone are connected to be driven by the audio
output circuit of the receiver. Alternatively, for operation of the
unit with an external source of stereo signals, a stereo input jack
is mounted directly to the headphone to receive the stereo signal
from a stereo plug wired to a source of stereo signals. When the
stereo plug is mated with the input jack, a switch incorporated in
the jack is mechanically actuated by the plug to disconnect the
speakers from the audio output circuit of the receiver and connect
the same to the contacts of the input jack. Since the switch is
mounted to the headphone jack and automatically actuated when the
stereo plug is inserted, no external switching operation is
required of the user for converting the unit from monaural
operation with the built-in receiver to stereo operation with the
external signal source.
The unit includes two muffs which are positioned to cover the ears
of the user. A cavity is formed in one of the muffs to house a
battery which powers the radio receiver and an ornamental cover is
provided over the muff to enclose the battery. An arm actuated
latch releasably secures the cover and muff together so that the
cover is easily removable for replacing the battery.
The above and still further objects, features and advantages of the
present invention will become apparent upon consideration of the
following detailed description of one specific embodiment thereof,
especially when taken in conjunction with the accompanying
drawing.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a perspective view of a headset unit according to the
present invention;
FIG. 2 is a top view of one muff containing a radio receiver with a
speaker support separated from the receiver to expose the receiver
and a speaker;
FIG. 3 is a top view of a second muff with the speaker support
separated therefrom to expose the underside of a battery cavity, an
input jack, a switch and a speaker;
FIG. 4 is a sectional view of the second muff taken along the line
4--4 in FIG. 3;
FIG. 5 is a detailed view of the cover latching mechanism of the
muff shown in FIGS. 3 and 4; and
FIG. 6 is a schematic diagram of the radio receiver circuit.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 is a perspective view of an entertainment unit 10 including
a combined stereo headphone and monaural radio receiver. The
headphone is a conventional type including a pair of muffs 12, 14
connected together by a resilient headband 15 for positioning the
muffs over the ears of a user. Ornamental covers 16 and 18 are
respectively provided to partially enclose the exposed surfaces of
the muffs 12 and 14. While the covers 16 and 18 have the appearance
of a football helmet in FIG. 1, it is understood that any other
suitable configuration can be used.
The muff 12 contains a monaural radio receiver 20, preferably of a
transistorized printed circuit type, and includes a bowl shaped
enclosure 22 covered by a lid 24 which supports a speaker 26 that
faces an ear of a user when the unit 10 is worn. A combination
on-off and volume control 28 and a tuner control 30 of the receiver
20 extend outside the enclosure 22 to permit adjustment of the
receiver while the unit 10 is worn.
The other muff 14 (FIG. 3) similarly includes an enclosure 32 and a
lid 34 which supports a speaker 36. A cavity 38, formed on an
exposed surface of enclosure 32, houses a battery 40 shown more
clearly in FIG. 4. Battery 40 is maintained against a cushion 58 in
the cavity 38 by a pair of ribs or projections 55 integrally formed
to the cover 18.
Of particular importance to the present invention is a stereo input
jact 42 having a switch 46 mounted thereto connected to the
enclosure 32 by screws 44. An actuator portion 50 of the switch 46
is disposed adjacent the input jack 42 and is adapted to be pushed
upwardly by a stereo plug 48 as the plug and jack are mated when
operation of the unit 10 with an externally provided stereo signal
is desired.
The switch 46 is a conventional triple pole, double throw momentary
slide switch having the actuator 50 biased downwardly by a spring
52 within the switch. The actuator 50 electrically switches three
ganged sections S.sub.1, S.sub.2, and S.sub.3 (not shown but
illustrated schematically in FIG. 6) of the switch 46 which
connects to the input jact 42, the radio receiver 20 and the
speakers 26 and 36 through the terminals 54, as will be described
in more detail infra. For present purposes it is sufficient to
state that when the stereo plug 48 and jack 42 are not mated, the
actuator 50 is maintained in the downward position by the spring 52
to connect speakers 26 and 36 for monaural operation with the
receiver 20. Alternatively when the stereo plug 42 and the input
jack 48 are mated, the actuator 50 is forced upwardly by the plug
to convert the unit 10 so that speakers 26 and 36 are driven by
separate channels of a stereo signal applied to the input jack via
the stereo plug.
The ornamental cover 18 is secured to the enclosure 32 with a latch
59, shown in detail in FIG. 5. The latch 59 is formed of a
key-shaped lug 60 secured to an operating arm 62 by a screw 64
extending through a stand-off 66. As the arm 62 is manually rotated
about screw 64, both the stand-off 66 and the lug 60 rotate
correspondingly by means of the coupling of the screw 64. A
receiving portion or island 68 formed on the enclosure 32 contains
a keyhole shaped slot or aperture 70 with a rim 72 adapted to
receive the lug 60 of the latch assembly. The rim 72 receives and
supports the stand-off 66 as the lug 60 and slot 70 are mated by
bringing together the cover 18 and enclosure 32 with the lug and
slot in mutual alignment, and the stand-off spaces the ornamental
cover from the enclosure. The island 68 is hollow so that the lug
60, when inserted into the slot 70 and rotated clockwise with the
arm 62, becomes latched therein and unremovable until the lug is
rotated counterclockwise in alignment with the slot 70.
Thus, in operation, the ornamental cover 18 enclosing the battery
40 is easily latched to the enclosure 32 by the user's aligning the
cover with the enclosure, the lug 60 extending into the keyhole
slot 70. Thereafter, arm 62 is manually rotated clockwise to cause
the lug 60 to be latched within the hollowed out portion of the
island 68. When a battery is to be inspected or replaced the user
merely rotates the arm 62 counterclockwise to realign the lug 60
with the slot 70 to remove the cover 18.
The operation of the unit 10 will now be described referring to the
schematic diagram of FIG. 6. A receiver circuit 56 is powered by
the battery 40 connected in series with an SPST on-off switch 74
incorporated in the control 28 in FIG. 2. When the switch 74 is
closed corresponding to the receiver circuit 56 being "on", the
negative terminal of the battery is connected to the common lead or
ground 76 of the receiver circuit through the S.sub.1 section of
the switch 46, discussed in more detail following a brief
description of the receiver circuit.
The receiver circuit is a standard monaural, a.m. superheterodyne
type and a detailed description thereof is not necessary to an
understanding of the invention. However, the receiver includes a
combination radio frequency amplifier and mixer stage 78 for
amplifying a radio signal received by an antenna 80 and converting
the signal to an intermediate frequency for further amplification.
The antenna 80 is preferably a conventional loop wound on a ferrite
rod mounted directly on the printed circuit substrate 20 of the
receiver in FIG. 2. Intermediate frequency amplifier 82 amplifies
the converted signal and drives detector circuit 84 which
demodulates the intermediate frequency signal to provide a monaural
audio frequency signal suitable for driving the speakers 26 and 36
following power amplification.
An audio driver stage 86 applies the audio output signal of the
detector 84 to a standard push-pull amplifier stage 88. The
push-pull amplifier stage 88 is a typical class-B complimentary
transistor type including compensating diodes 90 and 92 for
minimizing crossover distortion caused by transistor mismatch or by
discontinuities at the change over point between half cycles of the
amplified audio waveform. The output terminal 98 of the amplifier
88 is applied across the two speakers 26 and 36, connected in
series to each other for monaural operation in response to the
receiver output.
The input jack 42 shown most clearly in FIG. 4 contains electrical
terminals 96l, 96r and 96g which correspond to the left and right
channels, and ground, respectively, of an external stereo signal
source, such as derived from phonograph, tape playback system or
stereophonic f.m. receiver. When the stereo plug 48 is mated with
the jack 42, the jack terminals 96l, 96r and 96g make contact with
corresponding terminals in the plug. More specifically, during
operation of the unit 10 with an external stereo signal, that is,
when the plug 48 and jack 42 are mated, the terminal 96l of the
jack receives the left channel component of the externally applied
stereo signal, the terminal 96r receives the right channel
component and the terminal 96g receives the common or ground line
of the stereo signal source.
When the unit is operated with the built-in receiver 56, that is,
when the stereo plug 48 is not mated with the stereo jack 42 on the
unit 10, the speakers 26 and 36 are connected in series with each
other between the output 98 of the audio amplifier 88 and the B+
line 94 (positive terminal of the battery 40) through switch
contacts h-j and e-f in sections S.sub.2 and S.sub.3 of the switch
46. It is understood that when the plug 48 and jack 42 are not
mated, the sections S.sub.1, S.sub.2, and S.sub.3 of the switch 46
are maintained in the positions shown in FIG. 6 by the action of
the spring 52 against the actuator 50 in FIG. 4. However, when the
actuator 50 is upwardly displaced by the insertion of the plug 48,
the ganged sections S.sub.1, S.sub.2 and S.sub.3 are switched,
i.e., the terminals b and c in section S.sub.1 become bridged
simultaneously with the terminals d and e in section S.sub.2 and
the terminals g and h in section S.sub.3.
The speakers 26 and 36 are each nominally 8 ohms and although a
mismatch occurs between the series connected speakers (16 ohms) and
the output of the push-pull amplifier circuit 88 (approximately 8
ohms), the output power of the class-B push-pull amplifier 88 is
more than adequate to drive the speakers 26 and 36, and the audio
system performs satisfactorily. The volume of the sound reproduced
by the speakers 26 and 36 is adjusted with the volume control 28
and the frequency of the signals is adjusted by variable tuned
circuits 100 and 102 forming the tuner 30.
It is not necessary to turn off the receiver circuit by manually
opening the switch 74 with the control 28 when the unit 10 is
operated with an external source of stereo signals because the
negative terminal of the battery is automatically disconnected from
the power supply ground terminal 76 of the receiver circuit 56 by
the switching of the switch section S.sub.1 from the terminals a-b
to the terminals b-c when the stereo plug and jack are mated.
As mentioned above, when the stereo plug 48 is inserted into the
stereo input jack 42 mounted to the enclosure 32, the ganged
portions S.sub.1, S.sub.2 and S.sub.3 of the switch 46
simultaneously switch to bridge across the terminals b-c, d-e and
g-h, respectively. Following the schematic diagram of FIG. 6, it
can readily be seen that when the plug and jack are mated, a
connection from the stereo jack contact 96g to a lead of each
speaker 26 and 36 is provided through the connections of the switch
section S.sub.1 across the terminals b-c and of the switch section
S.sub.2 across the contacts d-e. The remaining lead 106 of the
speaker 26 is connected to the stereo jack contact 96r through the
connection of switch section S.sub.3 across the contacts g-h and
the remaining lead 108 of the speaker 36 is directly connected to
the input jack terminal 96l. Accordingly, when the stereo plug 48
and input jack 42 are mated, the speakers 26 and 36 are connected
to the input jack contacts 96g, 96r, and 96l to receive a stereo
signal applied thereto. That is, the left channel signal component
of the stereo signal applied between the contacts 96l and 96g of
the stereo plug 48 is connected to the left channel speaker 26, and
similarly, the right channel signal component applied between the
input jack contacts 96r and 96g is connected to the right channel
speaker 36. During operation with an external stereo signal, the
electrical connection 110 remaining between the audio output 98 and
the speaker 36 has no effect on either the receiver circuit or the
speakers since, except for the lead 110, the speakers are
completely disconnected from the receiver circuit.
Obviously, numerous modifications and variations of the present
invention are possible in light of the above teachings. For
example, without departing from the spirit of the invention, the
headphone could be of a quadraphonic type including four speakers
and four corresponding input channel contacts in the input jack. As
another variation, the radio receiver could be either an a.m. or
f.m. type and the speakers could be connected together in parallel.
Further, both muffs can contain the latching mechanism of FIG. 5,
e.g., the cover 16 can be releasable and the receiver 20 displaced
to expose a cavity in the muff 12 for storing a spare battery or
other item. It is therefore understood that within the scope of the
appended claims, the invention may be practiced otherwise than
specifically described herein.
* * * * *