Note: Descriptions are shown in the official language in which they were submitted.
2I4~83 1
This invention relates to a system for the simul-
taneous generation of mechanical motion and voltage. In
one particular embodiment, it relates to portable audio
cassette players.
In many parts of the world there are locations without
electric power lines. This means that electrical devices
need to be battery operated. Moreover, in many such
regions, batteries can be difficult to obtain and may fur-
thermore be relatively expensive.
In many instances travellers, who rely on batteries to
power electrical devices, may be disappointed when the
batteries run out. In Arctic regions, it is known that
batteries lose power rapidly dependent on the temperature.
Loss of battery power for electrically-powered devices
would be serious. In many other instances for emergency
application, an electrical device may not be used fre-
quently but it must be reliable when such use is essential.
Under such conditions, batteries must be checked periodi-
cally to ensure that power is available as and when
required.
Playback equipment for audio recordings is well known.
Earliest examples of audio players were phonographs for
reproducing sound recorded as an unevenness in the surfaces
of grooves formed upon records. These initially were
cylindrical and later were made in a flat circular form.
In the use of a phonograph for playing flat records, for
instance, a record is rotated upon a turntable beneath a
tone arm which, in known manner, is caused to vibrate by
`- 21458~1
its engagement with the uneven groove surface of the
record. These vibrations are converted into electrical
impulses corresponding to the vibrations and these impulses
are transmitted to an amplifier which amplifies the
impulses as sound. Originally, prime movers comprising
manually windable driving springs were incorporated into
phonographs for rotating turntables. Examples of such
constructions are shown, for instance, in early Canadian
Patent No. 222,126 granted in 1922, Canadian Patent No.
286,381 granted in 1929 and Canadian Patent No. 301,670
granted in 1930. In these patents, governors are described
as being incorporated to ensure that the turntables are
rotated at a controlled constant speed.
While mechanical prime movers were used for rotating
turntables during early designs of phonographs and such
prime movers were used over a lengthy period of years, the
phonographs were, for all other purposes, operated by elec-
trical power. As advancements were made in electrical
engineering and new electrical devices were being developed
and were being improved, after the 1920's, new designs of
phonographs incorporated electrically powered driving
means for rotating the turntables. As a result, from that
particular time onwards all operations, including the
driving of turntables, of phonographs have been operated by
2S electrical power.
More recently, audio cassette and then compact disc
technology has been developed as other means of recording
sound. Audio cassette players and compact disc players are
214583 1
operated completely by electrical power, as is only to be
expected with present tec-hn;cal knowledge. Electrical
power for this purpose is provided either from the general
electrical power supply, or, in the case of portable audio
cassette and compact disc players, from batteries.
There are problems, however, with present-day batter-
ies which may detract, under certain conditions, from the
appeal of audio cassette players and compact disc players.
For instance, in extremely cold weather conditions, batter-
ies are known to lose power and this may result in a fail-
ure in their operation. In addition, present-day batteries
have a limited useful life under any temperature condition
and replacement batteries may be difficult or even impos-
sible to find in certain geographical regions.
Recognition of many of the above problems was provided
in G.B. Patent Application No. GB 2,262,324 A, published
16.06.1993 in the name of T.G. Baylis. That publication
provided an electrical generator for powering a radio which
comprised a spring motor which was wound up by way of a key
such that the subsequent rotation of a torque drum as the
stressed spring unwound therefrom generates electrical
power. The rotational speed of the drum was geared up by
gear means and rotated the rotor of an electrical motor to
generate an output voltage. The output voltage was regu-
lated by way of a Zener diode and was fed to a radio by wayof a jack plug.
The present invention is concerned with devices which
require both mechanical motion and electrical energy and
214S8~1
seeks to provide such a device, which, in use, will obviate
the above problems.
Accordingly, it is an object of one aspect of this
invention to provide a system for the simultaneous gener-
ation of mechanical motion and electrical energy using asimple mechanical device.
An object of another aspect of this invention is to
provide such a device which is equally operative in
tropical regions and in Arctic regions.
An object of yet another aspect of this invention is
to provide such a device which does not use batteries and
thus is more economical to operate.
An object of still another aspect of this invention,
is to provide such a device which, since it does not use
batteries, obviates the problem of battery disposal, which
can contaminate landfills if they are buried, or otherwise
cause ecological problems.
A more particular object of the present invention is
to provide an audio cassette or compact disc player which
takes advantage of a system as previously indicated as
being desirable.
By one broad aspect of this invention, a system is
provided for the generation of mechanical motion driven by
a rotatable drive shaft, and for generating a voltage out-
2S put by electrical generating means having a rotor driven ata desired speed, the system including a prime mover com-
prising: a windable driving spring means, the spring means
including an interconnecting drive train for separately
- 2145~
drivably connecting the spring means to the rotatable drive
shaft and to the rotor of the electrical generating means;
and speed governing means for controlling the unwinding of
the spring means so as to cause the spring means to drive
the rotatable drive shaft and the rotor of the electrical
generating means at the predetermined desired speeds.
By another broad aspect of the present invention, an
audio cassette player is provided having the conventional
rotatable drive shaft for driving an audio cassette tape
progressively through a signal pick-up station to permit a
playback head to receive signals from the tape and ampli-
fying means electrically connected to the head to receive
signals from the head. The essential element of the prime
mover comprises a windable driving spring means drivably
lS interconnected by a drive train both to the rotor of an
electrical generating means having a rotor driven at a
desired speed for providing electrical power to the
amplification means and to the rotatable drive shaft. An
essential speed governing means is provided for controlling
the unwinding of the spring means so as to cause the spring
means to drive the drive shaft and the rotor of the elec-
trical generating means each at their own predetermined
desired speeds.
In an audio cassette or compact disc player according
to an aspect of the invention, the use of a battery
together with its inherent problems, is completely avoided.
Instead of a battery, the windable driving spring means is
provided which has a dual function in that it drives not
- 21~831
only the rotatable drive shaft, but also the rotor of the
electrical generating means which supplies the required
electrical power to the amplification means.
The system of this invention is useful in many more
embodiments than an audio cassette or compact disc player.
It may be used to generate and provide mechanical motion
and/or generate electrical energy for many devices. Among
them are radios, lamps, games, consoles, lap top computers,
children's toys which now include both mechanical movement
and generate sound, realistic dolls, etc. It also has
utility in cases of power outages and for military communi-
cation maintenance.
As noted above, the incorporation of an electrical
generating means together with a mPch~n;cal prime mover in
the form of a windable spring means avoids the necessity of
providing electrical power from an outside source, i.e., by
the use of a battery. This is of particular importance
where the device is portable, although this advantage is
seen as also to apply to non-portable devices, i.e., for
use in remote areas. In addition, a portable device
according to aspects of the invention may be used in cold
temperature conditions without any deterioration in the
capability in its operation. The prime mover in the form
of the windable driving spring means is virtually
unaffected by such conditions. Further, because the device
according to aspects of the invention generates its own
electrical power, any concern is avoided regarding the
- 21~58~1
necessity of renewing the reserve of electrical power
obtained from an outside source.
A portable device according to an aspect of the inven-
tion is particularly useful in military circumstances as
there is no requirement for an outside source of electrical
power. In addition, a device according to an aspect of the
invention may remain unused for extended periods and will
be found to be in perfect operating condition when its use
is next required.
In one variant of the audio cassette player of an
aspect of the present invention, the interconnecting drive
train is connected to drive the rotatable drive shaft at
the desired speed to drive the cassette tape progressively
through the pick-up, e.g., at 4.7S lineal cm/sec.
In another variant of the audio cassette player, the
rotor of the generating means is adapted to be rotated at
speeds sufficient to provide constant voltage of 1.5 +0.01
volts. Such audio cassette player also may include a Zener
diode for fine tuning of the voltage supplied to the ampli-
fying means.
In yet another variant of the audio cassette player,
the interconnecting drive train comprises a gear train, the
gear train having a driving section which is connected to
the spring means and which is common for driving both the
rotatable drive shaft and the rotor of the electrical gen-
erating means, and two driven sections extending in paral-
lel from the driving section, with one of the driven sec-
tions drivably connected to the rotatable drive shaft and
2145831
._
the other driven section drivably connected to the rotor of
the electrical generating means.
In still another variant of the audio cassette player,
the electrical generating means comprises an alternator for
producing alternating current and a rectifier which is
electrically connected between the alternator and the
amplifying means for converting the alternating current
into direct current.
By yet another variant of the audio cassette player,
a frame is provided comprising top and bottom planar plates
which are held in required spaced-apart positions by four
corner bolts and spacers received on the bolts and extend-
ing between the plates. In a variation of such variant, a
tape deck platform is disposed above the top plate, the
platform being held spaced above the plate by spring-loaded
corner posts which provide the platform with a required
degree of resilient float, the platform thereby supporting
a tape drive mechanism above its upper surface. By still
another variation of such variant, the tape drive mechanism
is driven by a drive shaft carrying a main drive gear which
is rotatably received through the platform.
By yet a further variation of such variant, a magnetic
playback head of the tape deck is electrically connected to
an amplification circuit for amplifying the signal received
from the head to an audible audio signal. By a further
variation of such variant, such amplification circuit is
provided with electrical power by an electrical generating
means which comprises an alternator mounted within and
- 21~58~1
depending from the top frame plate, the alternator being
connected to the amplification circuit through an AC to DC
rectifier circuit.
By another variant of the audio cassette player, the
drive shaft and the rotor shaft of the alternator are both
driven by a single mechanical prime mover which comprises
a windable driving spring means in the form of a spiral
spring, such spring, together with an interconnecting drive
train to the spindle and to the rotor of the alternator,
being contained between upper and lower frame plates.
By yet another variant of the audio cassette player,
the inner end of the spring means is secured to a winding
shaft which is pivotally mounted between the upper and
lower plates and extends above the upper plate, an upper
end of the shaft having means to enable connection to
manual winding means.
By yet another variant of the audio cassette player,
the drive train is in the form of a gear train which has a
driving section connected to the spring and which is common
to both the rotatable drive shaft and to the alternator,
such driving section comprising a main driving gear rotat-
ably mounted upon a shaft beneath the spring means, a
ratchet beneath the gear and secured to the shaft and a
pawl mounted upon the gear and engaged with the ratchet,
the ratchet and pawl allowing for winding of the spring in
a clockwise direction with the gear stationery, the spring
being permitted to unwind, thereby transmitting its drive
to the gear through the ratchet and pawl.
- 21~5831
By a still further variant of the audio cassette
player, in the driving section of the gear train, a gear
drives a sprocket gear which is drivably connected to a
shaft and to a larger diameter coaxial gear, such gear in
turn driving a small diameter gear which is drivably con-
nected to the shaft and to a larger diameter coaxial gear.
By a variation of this variant, the driving section con-
nects with two driven sections of the gear train which
operate in parallel; one driven section, which drives the
rotatable drive shaft comprising a small diameter gear
captive on shaft, the gear being in mesh with another gear,
the shaft rotatably extending through the upper frame plate
and projecting through the platform to provide, at its
upper end, a capstan extending above the tape deck; a
second driven section of the gear train which drives the
alternator comprising a small diameter gear which drivably
secured to the rotor of the alternator and in mesh with a
larger diameter gear on shaft, the gear being driven by
gear on shaft.
By a still further variant of the audio cassette
player, the shaft is provided, between the upper plate and
the platform, with a flywheel, the flywheel being adapted
to resist any sudden acceleration or deceleration in rota-
tional speed of the shaft to eliminate any distortion in
the sound during playback of a tape, a pulley wheel dis-
posed above the flywheel, the pulley wheel being secured to
the shaft, and being drivably connected to a driven pulley
. 2145~3 ~
wheel by a pulley belt, the driven pulley wheel being
secured to the drive shaft.
The speed governing means may be any mechanical device
which provides a control over the rate of rotation of a
shaft. Among more common areas are the so-called "butter-
fly" governor, the so-called "fly-ball" governor, the so-
called "inertia or centrifugal inertia" governor, the so-
called "pendulum" governor, the so-called "Porter"
governor, the so-called "Proell" governor, the so-called
"Watt" governor, the so-called "shaft" governor, the so-
called "spring-loaded" governor, or the so-called
"Hartnell" governor. However, a preferred such speed
governing means according to another variant of this
invention comprises a fixed housing having an inner surface
with an axis of generation and being in the form of a
circle at any cross-sectional position taken normal to the
axis of generation, a rotatable mass disposed within the
housing and rotatably drivable by the driving spring means
about an axis of rotation coincident with the axis of
generation of the inner surface of the housing, the rotat-
able mass comprising a body and a plurality of arms resil-
iently flexibly connected at pivotal end regions to the
body in spaced positions around the body for resilient
pivotal movement of each arm outwardly from the body under
2S centrifugal force as the mass is rotated to cause the arms
frictionally to engage the inner surface of the housing,
with a resultant frictional drag increasing or decreasing
appropriately dependent upon any tendency for rotational
21458~1
speed of the mass to increase or decrease so as to maintain
a desired rotational speed of the mass consistent with the
predetermined desired speeds of the drive shaft and of the
electrical generating means. Preferably, the mass is
formed as a single moulded member. Additionally, each arm
is stiffer at positions along its length spaced from its
pivotal end region than at its pivotal end region whereby
resilient outwards pivoting movement of the arm occurs sub-
stantially completely at the pivotal end region and the
stiffness of the arm influences the degree of frictional
pressure applied to the inner surface of the housing. Pre-
ferably, each arm has an outer convex surface for engage-
ment with the inner surface of the housing. Still more
preferably, with the mass physically at rest, its peri-
pheral surface is substantially circular when viewed in anaxial direction and the pivotal end region of each arm is
defined between the peripheral surface of the mass and an
inner concave surface which provides a progressive widening
of the pivotal end region into the arm at one side of the
pivotal end region and into the body on the other side of
the pivotal end region to allow for stress distribution.
In another preferred speed governing means according
to an aspect of the invention, the speed governing means
includes a fixed housing with an inner surface having an
axis of generation which is in the form of a circle at any
cross-section normal to the axis of generation. In this
preferred structure of speed governing means, a rotatable
mass is disposed within the housing and is rotatably driv-
"- 21458:~ ~
13
able by the driving spring about an axis of rotation coin-
cident with the axis of generation of the inner surface of
the housing. The rotatable mass has a body and a plurality
of arms which are resiliently flexibly connected at pivotal
end regions of the arms to the body in spaced positions
around the body for pivotal movement of each arm outwards
from the body under centrifugal force as the mass is
rotated. This causes the arms frictionally to engage the
inner surface of the housing and a resultant frictional
drag increases or decreases appropriately upon any tendency
for rotational speed of the mass to increase or decrease
respectively. This action maintains a desired rotational
speed of the mass which controls and is consistent with the
predetermined desired speeds of each of the drive shaft and
the rotor of the electrical generating means. The pre-
ferred structure of the speed generating means is parti-
cularly pertinent to an aspect of the present invention in
that it may be made sufficiently small to be incorporated
as part of a portable audio cassette player which, by its
very nature, is required to be of as compact a construction
as possible. By another variant of the audio cassette
player, the mass of the speed governor means is fixed con-
centrically to a rotatable shaft which is drivably inter-
connected by gears of the interconnecting drive train to
the spring means.
In more general terms, the system of broad aspects of
the present invention may be used to power an electrical
device, e.g., an audio cassette or compact disc player or
214~31
-
14
a radio. As the power is generated mechanically from the
spring motor, no electrical power from power lines is
required for the operation of the device. Furthermore, the
store of mechanical energy may be replenished by physical
effort, that is, by rewinding the spring. There is no
necessity to purchase batteries or other energy sources in
order to keep the electrical device in working order.
Thus, the electrical device to be powered by system of
aspects of the present invention may be any type of elec-
trically-powered device currently available. Preferably,
however, the electrical device is portable and is one which
is unlikely to require substantial electrical power levels.
The prime mover, i.e., the spring, may comprise a
logarithmic spring or a spring conforming to Hookes' Law,
or a metal band spring arranged to deliver a substantially
constant force. For example, the metal band spring may be
pre-stressed band of steel.
Means to wind the spring, e.g., a wind-up key is pro-
vided and is arranged to wind the metal band spring. This
mechanical wind-up process stresses the spring and thus
stores mechanical potential energy. The potential energy
is thereafter released by the unwinding of the spring and
this causes rotation of the rotor of the alternator which
thereby generates electrical power. It also provides
rotation to a shaft which provides mechanical motion.
Locking means is provided to enable the spring to be
locked in its condition storing potential energy. It is an
easy matter to wind up the spring motor again when it is
214~83 ~
required to power the electrical device. However, it is
generally preferred to provide appropriate protection
mPc-h~n;sms, e.g., appropriate stops, to prevent overwind or
underwind of the spring.
The means to generate the electrical energy may be any
type of electrical generator arranged to generate electri-
city in response to rotation of its rotor. For example,
the rotor may be permanent magnet rotor rotatable within a
stator carrying one or more electrical coils. Alterna-
tively, the rotor may carry the electrical coils, while the
stator carries one or more permanent magnets. It is pre-
ferred that it is arranged to be as compact and lightweight
as possible. An alternator is preferred where the powered
device is to be an audio cassette or compact disc player.
The gear means comprises a series of inter-engaging
gears arranged to rotate the main drive shaft at a high
speed of rotation. The gear means is designed to gear up
the speed of rotation of the main drive shaft to an appro-
priate speed. The gear means may be constructed in any
appropriate manner. Preferably, the gear means comprises
a series of inter-engaging gear wheels. The gear means
should be arranged to have a low friction and it is also
preferred that the gear means is lightweight.
The system thus includes a tensioned steel band spring
to rotate a torque output shaft. When in its unstressed
position, the spring is wound. This wind-up process thus
stresses the spring such that mechanical potential energy
`- 21458~1
is stored in the wound spring. The energy stored, and the
torque generated thereby is subsequently delivered.
When the spring has been wound, it tries to unwind to
release the stress to which it has been subjected, and in
doing so rotates the main drive shaft. The main drive
shaft is connected by a series of gears to the mechanical
motion apparatus and the rotor of the electrical generator.
The gear means comprises a plurality of gear wheels which
are intermeshed and which are arranged to gear up the
rotation of the main output shaft.
In the accompanying drawings,
Figure 1 is a plan view of the inside structure of a
portable audio cassette player of one embodiment of the
invention with an outside cover removed;
Figure 2 is an elevational view of the player viewed
from the direction of arrow II-II in Figure 1;
Figure 3 is an elevational view of the player viewed
from the direction of arrows III-III in Figure 2;
Figure 4 is an underside view of the player viewed
from the direction arrows IV-IV in Figure 2, with part of
a frame of the audio cassette player removed for clarity;
Figure 5 is a cross-sectional view of part of the
audio cassette player taken along line V-V in Figure 3;
Figures 6 and 7 are cross-sectional views taken along
lines VI-VI and VII-VII in Figure 4, respectively;
Figure 8 is a cross-sectional view of the governor
part of the audio cassette player taken along line VIII-
VIII in Figure 6; and
2145831
Figure 9 is a view similar to Figure 8 with the audio
cassette player in operation.
As shown in Figures 1 - 7, a portable audio cassette
player 10 comprises a frame comprising top and bottom
planar plates 12 and 14, which are held in required spaced-
apart positions by four corner bolts 16 and spacers 18
received on the bolts and extending between the plates 12
and 14. Above the plate 12 is disposed a tape deck, com-
prising a tape deck platform 20 of known construction, the
tape deck platform being shown in planar form. The platform
20 is held spaced above the plate 12 by spring-loaded
corner posts 22 which provide the platform 20 with a
required degree of resilient float for known reasons. The
platform 20 supports a tape drive mechanism 23 above its
upper surface (see Figure 1 particularly). The tape drive
mechanism is of known construction and will not be further
described except to indicate that the mechanism 23 is
driven by a drive shaft 24 carrying a main drive gear 26 of
mechanism 23 and rotatably received through the platform
20.
Also conventionally, the tape deck is provided with a
magnetic playback head 28 which is disposed appropriately
in a signal pick-up station at one side of the platform and
of the frame plate 12 as shown, for instance, in Figures 1
and 3. In known manner for portable audio cassette
players, the playback head 28 is electrically connected to
a suitable amplification circuit (indicated diagrammati-
` 21~S831
18cally as item 30 Figure 1) for amplifying the signal
received from the head to an audible audio signal.
Still further, conventionally, the tape drive mecha-
nism includes a "play" button 25 which moves plate 27 to
engage into a "play" position, and a "stop" button 29.
Stop button 29 includes vertically-moveable pin 31 which
can be inserted between the teeth of gear 65 mounted on
shaft 68 to stop the movement of the tape.
By this structure, means are provided for: driving the
tape at the standard speed in order for the electro-
magnetic head to read the signal on the tape (equivalent to
"play"); disengaging the electro-magnetic head and advanc-
ing the tape at high speed (equivalent to "fast forward");
and disengaging the head while interrupting the drive
train, so that the ribbon no longer advances (equivalent to
"stop"). In addition the spring no longer rotates the
rotatable drive shaft.
The amplification circuit 30 is provided with electri-
cal power by an electrical generating means which comprises
an alternator 32 mounted within and depending from the
frame plate 12. The alternator is connected to the ampli-
fication circuit 30 through an AC to DC rectifier circuit
34, also shown diagrammatically in Figure 1.
The drive shaft 24 and the rotor shaft of the alter-
nator 32 are both driven by a single mechanical prime moverwhich comprises a windable driving spring means in the form
of a spiral spring 36. This spring, together with an inter-
connecting drive train to the spindle 26 and to the rotor
21~58:31
._
19
of the alternator 32, is contained between the frame plates
12 and 14 as will now be described. In one specific embo-
diment, the spiral spring 36 may be made from pre-stressed
steel with a thickness of 0.61 mm, width 15.63 mm and a
S length of 1250 mm. For winding purposes, an inner end of
the spring 36 is secured to a winding shaft 38 (Figures 2,
4, 6 and 7) which is pivotally mounted between the plates
12 and 14 and extends above the plate 12. An upper end 40
of the shaft 38 is of square cross-section suitable for
manual winding with a key 42 (in chain-dotted outline in
Figure 2). An outer end 44 of the spring 36 is perma-
nently secured around one of the corner spacers 18
extending between the plates 12 and 14.
The drive train is in the form of a gear train which
lS has a driving section connected to the spring 36 and which
is common to both the rotatable drive shaft 24 and to the
alternator 32. This driving section comprises a main
driving gear 46 which is rotatably mounted upon the shaft
38 beneath the spring 36 as shown in Figure 4. Beneath the
gear 46 is disposed a ratchet 48 which is secured to the
shaft 38 and a pawl 50, which is mounted upon the gear 46
and engaged with the ratchet 48. The ratchet 48 and pawl
50 allow for winding of the spring 36 in a clockwise
direction (as viewed in Figure 4) with the gear 46 station-
ary. The spring 36, however, cannot unwind (i.e. anti-
clockwise) without transmitting its drive to the gear 46
through the ratchet and pawl. Means are provided in asso-
21458~1
ciation with the spring to override the ratchet and pawl to
permit unwinding of the spring.
It is intended that the drive shaft 24 and the alter-
nator 32 both be driven at operational speeds far in excess
of the unwinding speed of the spring 36. The gear train
takes account of this requirement. The gear train is shown
in Figures 6 and 7 in particular in which parts of the
player unnecessary to this part of the description are not
included for purposes of clarity.
In the driving section of the gear train, the gear 46
drives a sprocket gear 52, which is drivably connected to
a shaft 54, and a larger diameter coaxial gear 56. The
gear 56 in turn drives a small diameter gear 58, which is
drivably connected to shaft 60, and a larger diameter
coaxial gear 62. This completes the driving section of the
gear train.
The driving section connects with two driven sections
of the gear train which operate in parallel. One driven
section, which drives the rotatable drive shaft 24 from the
tape drive (Figure 6), comprises a small diameter gear 64
which is captive on shaft 66, the gear 64 being in mesh
with the gear 62. The shaft 66 also drives gear 65 and
rotatably extends through the upper frame plate 12 and
projects through the platform 20 to provide at its upper
end a capstan 68 extending above the tape deck. This
capstan 68 (Figure 1) is of known construction and usage
and co-operates with pinch roller 70 mounted on a pivotal
arm 72 above the platform 20. The capstan 68 and the pinch
2145~31
roller 70 co-operate in known manner for driving a cassette
tape forward at an industry st~n~rd speed of 4.75 cms per
second.
As may be seen most clearly from Figure 6, the shaft
66 is provided between the plate 12 and the platform 20
with a flywheel 73. The flywheel 73 resists any sudden
acceleration or deceleration in rotational speed of the
shaft 66 to eliminate any distortion in the sound during
playback of a tape. Immediately above the flywheel 73 is
disposed a pulley wheel 74 which is secured to the shaft 66
(see also Figure 5). The pulley wheel 74 is drivably con-
nected to a driven pulley wheel 76 by a pulley belt 78.
The driven pulley wheel 76 is secured to the drive shaft 24
thereby completing the driven section to the drive shaft
24.
A second driven section of the gear train which drives
an electricity generator, i.e., an alternator 32 (Figure 7)
comprises a small diameter gear 80 which is drivably
secured to the rotor 8 5 of the alternator 32 and which is
in mesh with a larger diameter gear 82 on shaft 84, the
gear 82 being driven by gear 62 on shaft 60. The gear
ratio between the spring 36 and the alternator 32 may
generally be of the order of 1:1000.
A speed governing means 200 (as seen in Figs. 8 and 9)
is provided for controlling unwinding of the spring 36 so
as to ensure that the drive shaft 24 and the rotor 84 of
the alternator 32 are each driven at their own predeter-
mined desired speeds consistent with generally-recognized
21~5831
requirements. Particularly as shown by Figure 8, the speed
governing means 200 comprises a rotatable mass 86 which is
secured towards the lower end of a rotatable shaft 88
extending between top and bottom plates 12 and 14. The
shaft 88 is rotatably driven by the spring 36 through a
small diameter gear 90 which is mounted on the shaft,
(Figure 6), the gear 90 being in mesh with a gear 92 which
is secured to the shaft 66. The mass 86 acts as a fly
wheel and comprises a main body 94 which is rotatable
around the axis of shaft 88, and two arms 96 which are
spaced apart on opposite sides of the body 94. The arms 96
are resiliently flexibly connected at pivoting end regions
110 to the body 94 and are integrally formed with the body
from resilient rubber, e.g., by a moulding operation. In
axial view, as shown in Figure 8, the mass 86 is of cir-
cular configuration when stationery. In a stationery
position, each arm is in a radially inner position to form,
with the body, a slit 98 which lies along a chord of the
circular section. Each slit 98 opens at the peripheral
surface of the mass 86 at one end and terminates at the
other or closed end in a circular through hole 100. The
surface of hole 100 provides a concave surface at the
pivotal end region of the respective arm so that there is
a progressive widening of the pivotal end region around the
surface of the hole both into the arm and into the body so
as to allow for stress distribution during use. As may be
seen, each slit 98 ensures that its arm 96 first increases
in width as it extends from the pivotal end region, because
214 ~ 8 ~ 1
of the circular outside shape of the mass, and then
decreases in width to a free end 102 of the arm. This
shaping of the arm ensures that the arm is stiffer at
positions along its length which are spaced from the
pivotal end region.
The speed governing means also includes a stationery
housing 104 which has an inner surface 106 of circular
configuration and an axis of generation coincident with the
axis of rotation of the shaft 88. The housing 104 is
secured to the lower frame plate 14 (Figure 6). When
stationary, the outer circumference 108 of mass 94 is out
of contact with the inner circumference 106 of stationary
housing 104.
In operation with an audio cassette tape 118 mounted
upon the platform 20 in the tape deck, i.e. in the chain-
dotted outlined position shown in Figure 1, the spring 36
is caused to impart its drive to the gear train. Through
the gear train, the spring 36 drives both the rotor 86 of
the alternator 32 and the drive shaft 24 and causes the
speed governor mass 86 to rotate. The gear ratio between
the spring 36 and the mass 86 may desirably be of the order
of 1:4020. As the mass 86 is rotated, centrifugal force
causes the arms 96 to be pivoted outwards about their
pivotal end regions 110 thereby causing their engagement
with the inner surface 106 of the housing 104. The arms
are more rigid along their length than at their pivotal end
regions 110 and apply frictional pressure against the inner
surface of the housing. This produces a resultant fric-
21~58~1
24
tional drag which increases or decreases appropriately as
the arms tend to move further inwards or outward dependent
upon the tendency for the rotational speed of the mass to
increase or decrease. Thus the mass 86 is caused to slow
down if it tends to rotate too fast or is allowed to speed
up should there be a tendency for it to be rotating too
slowly. As a result, the rotational speed of the mass 86
(and hence shaft 88) is maintained at its desired speed
consistent with providing the predetermined desired speeds
of each of the drive shaft 24 and the rotor 86 for the
electrical generating means 32.
Hence the tape 118 is fed at its desired speed through
the pick-up station to enable the playback head to receive
magnetic signals from the tape and relay these signals to
the amplification circuit 30. The alternator 32 provides
electrical power, which may be e.g., of 1.5 volts output,
through the rectifier circuit 34 to the amplification
circuit 32 so that sound from the tape may be heard by the
user through a pair of earphones. It should be noted that
although the alternator 32 is driven by its own driven gear
section and that the governing means is provided upon the
other driven gear section for rotating the drive shaft 24,
nevertheless the governor controls the driven speed of the
shaft 86 of the alternator 32 as well as that of the drive
shaft 24. As indicated, the voltage output from the alter-
nator 32 is of the order of 1.5 volts. However, although
this voltage is held constant by the effect of the speed
governing means, nevertheless a Zener diode (not shown) may
- 21~5831
be included in the circuit to provide fine tuning to the
voltage.
As may be seen in the above embodiment, the portable
audio cassette player is not dependent in use in any way
S upon batteries. Instead, the audio cassette player is
driven in its entirety by a mech~n;cal prime mover in the
form of the spring 36. This spring 36 operates both the
drive shaft 24 and also the rotor shaft 86 of the alter-
nator 32 for generating the electrical power necessary for
the amplification of the sound.
Thus, it is seen that the present invention provides
many useful advantages in many parts of the world, while
electrical radios and audio cassette or compact disc
players are widespread, there is no central electrical
power supply. Therefore, such devices are battery powered.
However, the batteries themselves are not always easily
available, and even if they are, are generally very
expensive compared with the local cost of living. For this
reason, the owners generally operate their radios only
infrequently so that they can save and conserve battery
power. This is a disadvantage in a region where it would
be advisable and advantageous for information could be made
available much more readily to the local people.
The present invention thus provides a portable elec-
trical audio cassette or compact disc player or radio whichcan be powered simply by winding it up, as was the case
with clockwork clocks and watches. This means that no
batteries have to be obtained.
-- 21~S831
26
Such devices, which do not require batteries, are also
environmentally and economically advantageous, particularly
in rural, poor communities. Presently, many poor economies
spend a disproportionately large proportion of their
resources on acquiring batteries for electrical devices.
Where the financial resources are not available, natural
resources are utilised to fund the acquisition with conse-
quent disadvantage to the present and future economy. Fur-
thermore, there is a problem of disposal of the spent
batteries which contaminate the land if they are buried and
land which might have been utilized for agriculture becomes
unavailable. All of these ecological problems are avoided
by the use of wind-up devices provided by aspects of the
present invention.
As discussed hereinabove, the electrical device
powered by the stored mechanical energy may be a device
other than an audio cassette, or compact disc player, or
radio. The invention also has many other applications.
For example, travellers may find it more convenient to
carry mechanically-powered electrical devices on their
travels so that they are not let down if the battery runs
out. Travellers will not then have to carry spare
batteries or to try to find compatible replacements in a
foreign country.
2S The invention is also particularly useful for emer-
gency applications where an electrical device is not used
frequently but must be available for use reliably. For
example, if a battery-powered radio and/or transmitter is
2145831
provided in a life-raft or life-boat, it is currently
necessary to check the batteries frequency to ensure power
is available as and when required. The wind-up device of
aspects of the present invention has the advantage that,
once it has been wound up, it reliably provides power.
Because of the avoidance of the use of batteries the
audio cassette player (and any other such device) provide
various advantages. For instance, such device may be used
in extremes of cold weather without the temperatures
affecting the performance of the spring. As there is no
dependence upon the requirement for dry batteries, this
causes no problem in isolated geographical regions. In
addition, because no battery operation is required, the
device may be left unused almost indefinitely with the
assurance that it will operate in a positive fashion when
next it is required for use. With all of the above advant-
ages, the device of aspects of this invention is also suit-
able for military applications.
