U.S. patent number 3,664,060 [Application Number 05/121,701] was granted by the patent office on 1972-05-23 for model railroad electric locomotive sound system.
This patent grant is currently assigned to Pacific Fast Mail. Invention is credited to Robert H. Longnecker.
United States Patent |
3,664,060 |
Longnecker |
May 23, 1972 |
MODEL RAILROAD ELECTRIC LOCOMOTIVE SOUND SYSTEM
Abstract
An accessory includes a speaker mounted in the locomotive tender
electrically driven by an audio frequency signal from one or more
electronic sound generators simulating respectively a bell,
escaping steam either from an engine exhaust, leakage or blowoff,
and a whistle. The engine exhaust sound is timed by periodically
grounding the radio frequency oscillator of a timing circuit for
the escaping-steam-simulating generator by intermittently closing a
switch in the circuit effected by rotation of a driver wheel of the
locomotive. Selective controls enable the bell and whistle to be
operated at will and further enable the nature of the sounds of the
bell, exhaust and whistle to be modified. Direct current for the
locomotive driving motor, the audio frequency signal to drive the
speaker and the radio frequency signal to the locomotive-carried
switch for timing the simulated engine exhaust are all
simultaneously impressed on the two rails but electronic blocking
components included in the circuit prevent the engine-driving
direct current and the radio-frequency signaling current from
interfering with the speaker operation and prevent the audio
frequency signal and the radio frequency signal from leaking into
the direct-current power circuit.
Inventors: |
Longnecker; Robert H. (Glen
Mills, PA) |
Assignee: |
Pacific Fast Mail (Edmonds,
WA)
|
Family
ID: |
22398284 |
Appl.
No.: |
05/121,701 |
Filed: |
March 8, 1971 |
Current U.S.
Class: |
446/410 |
Current CPC
Class: |
G10K
15/02 (20130101); A63H 19/14 (20130101) |
Current International
Class: |
A63H
19/00 (20060101); A63H 19/14 (20060101); G10K
15/02 (20060101); A63h 019/10 (); A63h
019/14 () |
Field of
Search: |
;46/216,232,243P |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Mancene; Louis G.
Assistant Examiner: Cutting; Robert F.
Claims
I claim:
1. A locomotive sound mechanism for a model train device comprising
a locomotive, a speaker, and electronic audio frequency signal
synthesizing means for generating an audio frequency signal
generally matched to simulated locomotive sound and operable to
drive said speaker for emitting such simulated locomotive sound and
said electronic audio frequency signal synthesizing means being
remote from the train device.
2. The locomotive sound mechanism defined in claim 1, in which the
speaker is carried by the model train device.
3. The locomotive sound mechanism defined in claim 2, in which the
locomotive is propelled by an electric motor to which driving
current is supplied through rails on which the train device
travels, and the audio frequency signal synthesized by the
electronic audio frequency signal synthesizing means is transmitted
to the speaker through the rails on which the train device
travels.
4. The locomotive sound mechanism defined in claim 1, in which the
audio frequency signal synthesized by the electronic audio
frequency signal synthesizing means is generally matched to
simulated locomotive sound including simulated locomotive bell
sound.
5. The locomotive sound mechanism defined in claim 1, in which the
audio frequency signal synthesized by the electronic audio
frequency signal synthesizing means is generally matched to
simulated locomotive sound including simulated locomotive whistle
sound.
6. The locomotive sound mechanism defined in claim 5, in which the
audio frequency signal synthesizing means includes a plurality of
oscillators generally matched to different locomotive whistle sound
frequencies, respectively, and means for combining the audio
frequency signals produced by said plurality of oscillators.
7. The locomotive sound mechanism defined in claim 1, in which the
audio frequency signal synthesized by the electronic audio
frequency signal synthesizing means is generally matched to
simulated locomotive sound including simulated combined locomotive
whistle and escaping steam sound.
8. The locomotive sound mechanism defined in claim 1, in which the
audio frequency signal synthesized by the electronic audio
frequency signal synthesizing means is generally matched to
simulated locomotive sound including simulated locomotive escaping
steam sound.
9. The locomotive sound mechanism defined in claim 8, in which the
escaping steam sound includes simulated engine exhaust
chuffing.
10. The locomotive sound mechanism defined in claim 9, and timing
means synchronized with the speed of the model train device for
timing the simulated engine exhaust chuffing sound.
11. The locomotive sound mechanism defined in claim 10, in which
the timing means is synchronized with the rotation of a wheel of
the train device.
12. The locomotive sound mechanism defined in claim 11, in which
the timing means includes commutating switch means.
13. The locomotive sound mechanism defined in claim 11, in which
the timing means includes a radio frequency signal timing circuit
transmitting a radio frequency signal to the train device.
14. The locomotive sound mechanism defined in claim 13, in which
the radio frequency signal timing circuit includes rails on which
the train device travels by way of which the radio frequency signal
is transmitted to the train device.
15. The locomotive sound mechanism defined in claim 1, in which the
audio frequency signal synthesized by the electronic audio
frequency signal synthesizing means is generally matched to
simulated locomotive sound including at least two separately
generated audio frequency signals generally matched, respectively,
to corresponding sounds selected from the group consisting of
locomotive bell sound, locomotive whistle sound, escaping steam
sound and engine exhaust chuffing.
16. The locomotive sound mechanism defined in claim 15, and
integrating means for integrating separately generated audio
frequency signals simulating different locomotive sounds to be
impressed on the speaker.
17. The locomotive sound mechanism defined in claim 1, in which the
audio frequency signal synthesizing means includes two components,
one component being generally matched to simulated locomotive sound
including simulated locomotive whistle sound and the other
component being generally matched to simulated locomotive sound
including escaping steam sound, actuating means, and means operable
to condition said actuating means for controlling independently and
selectively the component generally matched to simulated locomotive
whistle sound and the component generally matched to simulated
escaping steam sound.
Description
A principal object of the present invention is to provide a single
electronic sound system accessory for model railroad locomotives
which can produce the sound of a bell, a whistle, or escaping steam
either as chuffing while the locomotive is traveling or steam
leakage when the engine is stopped, or steam blowoff.
A particular object is to provide an accessory by which any of
these sounds produced will be very realistic, and which can be
controlled to alter the tone, the volume and the duration.
Specifically it is an object to enable the sound of escaping steam
to be simulated as chuffing of the locomotive in precise
synchronism with the speed of the locomotive, as well as enabling
the sound to be altered to simulate working under heavy load or
light load.
A further object is to promote the realism of the sounds produced
by emitting them from the locomotive.
It is also an object to enable the operator to control the timing
and duration of the simulated bell, whistle and steam blowoff
sounds at will.
An additional object is to enable such simulated locomotive sounds
to be produced and controlled without interference with the
propulsion of the locomotive and the ability of the operator to
control its speed and direction of movement.
It is an object to provide such a locomotive sound system in which
the sounds emanate from the locomotive without requiring any
additional transmission wires or the use of radio transmission and
reception, but simply by using the railway tracks as
conductors.
FIG. 1 is a block circuit diagram including the circuitry for the
locomotive driving power and for the several electronic
sound-producing components.
FIG. 2 is a diagrammatic top perspective showing the circuitry in
the locomotive including cam mechanism closing a switch
periodically.
FIG. 3 is a fragmentary horizontal section of a portion of a
locomotive showing an alternative type of periodically closable
switch mechanism viewed from line 3--3 of FIG. 4.
FIG. 4 is a fragmentary vertical section taken along line 4--4 of
FIG. 3.
FIG. 5 is a top perspective of stationary and portable control
units.
Operating model trains have been available for a considerable
period of time. In many instances such trains have been accurate
scale replicas of the rolling stock of various railroads. Such
model trains have been powered to be operated by remote controls at
various speeds and, alternatively, in forward and reverse
directions. Moreover, such trains have been operated over elaborate
trackage systems. A principal deficiency of previous systems has
been their inability to simulate realistic locomotive sounds such
as the bell, the whistle and escaping steam.
Conventionally, a model train includes a locomotive 1 shown
diagrammatically in phantom in FIG. 2, propelled by driving wheels
2 running on rails 3 and 4. A simulated steam locomotive has a
tender 5, also shown in phantom perspective in FIG. 2, trailing
behind the locomotive, which usually is disengageably attached to
the locomotive. The driving wheels 2 of the locomotive are driven
by an electric motor 6 turning a worm 7 which meshes with a worm
gear 8, shown in FIGS. 3 and 4 as being secured on the axle 9
carrying the driving wheels 2.
Motive Power
Power for the locomotive propulsive system and sound system is
supplied from a conventional 110-volt alternating current supply
source through a conventional plug 10, which is connected to the
main line switch 11 shown in the circuit of FIG. 1, and on the
stationary control box of FIG. 5. The alternating current source
supplies power for the direct-current power supply 76 which is of
conventional type and may include a transformer, a full-wave
rectifier, and a filter capacitor. Such DC power supply is
connected through the throttle 13, which is a cascaded current
amplifier, to the rails 3 and 4 by way of a wire 14 and a grounded
wire 15. The DC power supply is also connected to ground.
Electrical power is supplied to the various components of the sound
system accessory by a regulator circuit 16 which provides a
constant-voltage direct-current source, such for example as 10
volts, irrespective of considerable fluctuation in the voltage of
the alternating current supply or differences in voltage of
different supplies. Because of the large number of components of
the sound system powered by such constant voltage direct-current
supply, such power supply connections are not shown in FIG. 1. Also
many of such circuit components are individually connected to
ground, but for simplicity such ground connections also are not
shown.
The speed of the motor 6 driving the locomotive driving wheels can
be altered at will by movement of the speed-control potentiometer
17, which controls the current output of throttle 13. Such motor is
of the reversible type, and its direction of rotation, and
consequently the direction of rotation of the locomotive driving
wheels, can be reversed at will by interchanging the leads to the
rails 3 and 4 by shifting the reversing switch 18. The motor 6 is
always connected in the same relationship to the rails 3 and 4
unless the locomotive is turned end for end.
Locomotive Construction
The manner in which the connection is made between the rails 3 and
4 and the motor 6 can be conventional. The locomotive wheels are
insulated from the locomotive frame on one side, and the tender
wheels are insulated from the tender frame on the opposite side.
The tender frame 19 thus constitutes one side of the motor circuit
to which it is connected through a separable connector 20 and a
wire 21, and the locomotive frame 22 constitutes the other side of
the electrical circuit. Such components are indicated
diagrammatically as electrical circuit components in FIG. 2. The
locomotive frame and the tender frame are connected by an
insulating mechanical drawbar-type coupling.
Sound Propagation
In order to produce the most realistic locomotive sound propagation
it is desirable both that the simulated sounds generated be of high
fidelity and that the sounds emanate from the locomotive as their
source. The simulated locomotive sounds are generated by electronic
audio frequency signal synthesizing means for driving a speaker 23
carried by the model train, which conveniently can be mounted in
the locomotive tender 5. One terminal of the speaker is connected
by wire 24 to the frame of the tender in circuit with rail 3, and
the other terminal of the speaker is connected by wire 25,
connector 26 and wire 27 with the frame 22 of the locomotive which
is in circuit with rail 4.
Through the connections mentioned above, the speaker 23 is
connected in circuit with the rails 3 and 4 continually, as long as
the locomotive 1 and tender 5 are coupled together, so that the
connector 26 connects wire 25 in the tender with wire 27 in the
locomotive. Electrolytic capacitors 28 are connected in
back-to-back series relationship in the wire 24 between the speaker
and the tender frame to provide a non-polarized capacitance for
blocking flow to the speaker of direct current for energizing the
driving motor 6 irrespective of the direction in which the direct
current flows. The value of such capacitors is not critical but
must be large enough to pass the lowest audio frequency signals
from the sound system destined for the speaker.
Locomotive sounds are produced by the speaker 23 driven by audio
frequency alternating current which may be composed of a blend of
several audio frequency signals integrated by the mixer section 29
and amplified by the audio amplifier 30. Such mixer section may
include a transformer mixing stack, the transformers of which
correspond respectively to the several types of signals generated
for the various locomotive sounds to be propagated. The intensity
of the blended audio frequency signal can be adjusted by the main
volume control potentiometer 31 to alter the overall volume of the
sound emanating from the speaker 23.
A blocking capacitor 32, preferably of the electrolytic type, is
interposed in the wire connecting the audio amplifier 30 to the
wire 14 connected to one of the rails for the purpose of blocking
flow to the audio amplifier 30 of direct current from the circuit
powering the motor 6. Also a choke coil 33 is included in the
circuit between the throttle 13 and the connection from the audio
amplifier for the purpose of blocking flow of the audio frequency
signal to the throttle direct-current circuit, which would drain
energy from the audio frequency signal and overload the audio
amplifier 30. The choke coil must be of sufficiently low resistance
to enable the direct current to flow from the throttle through wire
14 to the motor 6 substantially unaltered. Since the audio
frequency signal for driving the coil of speaker 23 is of
alternating current character, it is immaterial as far as the
speaker operation is concerned in which position the reversing
switch 18 is set.
Bell
The portion of the circuit which produces the bell component of the
audio frequency signal is within the dot-dash line enclosure of
FIG. 1, labeled "BELL." The bell tone is generated electronically
by an oscillator 34 which is gated by a bell-gating multivibrator
circuit 36. Such circuit produces intermittent bell-gating pulses
from the outputs of both halves of the multivibrator. These pulses
are properly shaped by resistance-capacitance networks to provide a
wave shape that will closely simulate the rise and decay of a bell
tone.
The striking pattern of the bell can be regulated at will primarily
by adjustment of the potentiometer 37 in one-half of the
multivibrator circuit. The basic symmetry of the multivibrator can
also be altered by opening or closing the switch 38 to the amount
of resistance in the other half of the multivibrator circuit 36
primarily to vary the striking rate of the bell. Operation of these
two controls provides sufficient variation of the ringing pattern
and rate to simulate a wide range of bell ringing effects. The bell
audio frequency component of the sound system passes to the mixer
section 29 through the wire 39 when the bell tone on-off switch is
in the "on" position shown in FIG. 1.
Escaping Steam
Steam escaping from an engine produces several different types of
sound, including the chuff of the exhaust from the steam engine
when the engine is propelling the locomotive, the hiss of steam
leakage and the blowoff effected automatically by opening of a pop
safety valve or intentionally in blowing down the boiler for
cleaning it out. The sound of escaping steam is basically the same
in all instances, and the circuit component for providing an audio
frequency signal simulating escaping steam in the various instances
mentioned is within the dot-dash line enclosure of FIG. 1 labeled
"STEAM."
The basic audio frequency for simulating the escape of steam is
generated by a random noise or white noise generator circuit 41.
This circuit will generate an audio frequency signal corresponding
to a wide range of sound frequencies. To modify such audio
frequency signal to simulate the sound of a steam engine exhaust a
portion of such signal is fed to the tone control and amplification
circuits for exhaust designated 42 in FIG. 1, and then to the final
stage exhaust amplifier 43 where it is gated to pulse in
synchronism with the speed of rotation of the model train. The
desired tone of the engine exhaust chuff can be selected by
adjusting the exhaust tone control potentiometer 44, and the
intensity of the exhaust sound can be altered by adjustment of the
exhaust volume control potentiometer 45. The modified audio
frequency signal for producing the simulated engine exhaust sound
is impressed on the mixer section 29 by way of wire 46.
Chuff Control Circuit
Periodic interruption of the random noise audio frequency signal
reaching the final stage exhaust amplifier 43 to simulate the chuff
of a steam engine exhaust is accomplished by a radio frequency
control circuit which effects electronic gating of the final stage
exhaust amplifier. Such radio frequency signal is originated by the
radio frequency oscillator 47. Such radio frequency signal passes
to the detector circuit 49, then to the pulse generating and
shaping circuits 50, and finally by way of wire 51 to the gate of
the final stage exhaust amplifier 43.
A wire 52 is connected between the radio frequency oscillator 47
and the detector circuit 49 to a wire 14 connected to one of the
rails 3 and 4, depending upon the position of the reversing switch
18. A capacitor 53 is interposed in wire 52 to block flow of direct
current from the locomotive driving electric motor circuit to the
oscillator 47 and detector 49. A radio frequency trap 54 including
an inductance and capacitance in parallel forming a resonant
circuit tuned to the frequency of oscillator 47 is interposed
between the connection of wire 52 to wire 42 and the throttle 13
direct-current circuit for preventing the flow of radio frequency
to the throttle circuit so as to avoid overloading the oscillator
47.
The radio frequency signal will pass from rail 3 through the tender
frame 19, connector 20 and wire 21, to one contact 55 of a switch
in the locomotive. The other switch contact 56 is connected by a
wire 57 to the locomotive frame 22, which is in circuit with the
other rail 4. When the radio frequency signal is continuous the
signal at the gate of the final stage exhaust amplifier 43 prevents
passage of an audio frequency signal through wire 46 to the mixer
section 29. When the radio frequency signal generated by oscillator
47 is grounded by closing of switch 55,56, the detector 49 produces
a gating pulse which triggers the final stage exhaust amplifier to
transmit only a single pulse to the mixer section.
The switch contact 56 is raised into engagement with the stationary
switch contact 55 when engaged by each corner of the square cam 58.
Such a cam is mounted to turn with the locomotive driving wheels 2,
so that the switch 55, 56 will be closed momentarily four times
during each revolution of the driving wheels. Such switch closure
produces a short circuit between the rails 3 and 4 for the radio
frequency signal, so that each time the switch 55,56 closes the
connection between the oscillator 47 and the detector circuit 49 is
grounded through the wire 52, the switch short between the rails,
and the ground wire 15. When the switch is closed, therefore, the
final stage exhaust amplifier 43 is gated to allow passage of only
a single audio frequency chuff signal from such amplifier by way of
wire 46 to the mixer section 29.
The shorting between rails 3 and 4 through switch 55,56 is
effective with respect to the radio frequency gate control signal
only, as described above, because the switch circuit has in it a
capacitor 59, which blocks transmission of the direct current for
energizing motor 6 from flowing through the switch 55,56 and
bypassing the motor. Also a radio frequency trap in the form of the
inductance-capacitance resonant circuit 60 tuned to the frequency
of oscillator 47 is included in the lead 24 from the tender frame
to the driving coil of speaker 23 so as to block flow of the radio
frequency signal from the rail to the speaker coil. Such trap
prevents the speaker coil from overloading the oscillator 47. It is
not necessary to provide a radio frequency trap in wire 21 to block
the radio frequency signal from reaching the motor 6 because the
windings of such motor have sufficient inductance themselves to
choke out the radio frequency signal.
The detector 49 generates one and only one pulse each time the
switch 55,56 is closed in the locomotive. The pulse-generating and
shaping circuits 50 monitor the output of the detector circuit 49
and vary the amplitude, shape and decay rate of the pulse in such a
manner as to provide a realistic chuff when fed as a gating pulse
to the gate of the final stage exhaust amplifier 43. The cutoff
control potentiometer 61 can be adjusted to vary the basic length
of the exhaust pulse so as to produce a chuff which will simulate
that produced either by a lightly loaded or a heavily loaded
locomotive as the operator may prefer.
FIGS. 3 and 4 illustrate a communicating type of switch mechanism
as an alternate to the switch 55,56 operated by the square cam 58
shown in FIG. 2. In FIG. 3 the wheel 2a engageable with track 3 is
insulated from the locomotive frame 22. The wheel 2b which engages
rail 4 is not insulated from the frame, but is connected
electrically to it through the axle 9. The wheel 2b has four
sectors 58a of insulating material and the remainder of the wheel
including the portions 56a between the insulating sections are
conductive and engage the rail 4. The sections 56a constitute one
switch contact member.
A spring silver contact wire 55a is mounted to press lightly on the
back of the uninsulated driver wheel 2b, but will touch conductive
sections 56a of that wheel at only four locations between the
insulating sectors 58a. Contact of the wire 55a with such
uninsulated portions of the wheel 2b close the radio frequency
shorting circuit between the rails 3 and 4.
The commutating type of switch construction shown in FIGS. 3 and 4
has practical advantages over the cam-operated switch mechanism of
FIG. 2. Principally, engagement of the contact member 55a with the
back of wheel 2b produces very little resistance to rotation of
such wheel, and such resistance is uniform in all rotated positions
of the wheel instead of the resistance varying with the rotative
position of the wheel as in the case of the square cam shown in
FIG. 2. Also the switch structure of FIGS. 3 and 4 is more
economical to construct and can be installed readily on existing
model locomotives to which the sound system accessory of the
present invention is applied.
Whistle
The circuitry for providing the whistle-simulating component of the
audio frequency signal transmitted to the speaker 23 is within the
dot-dash enclosure of FIG. 1 labeled "WHISTLE."
To produce an electronic audio frequency signal for simulating
realistically the sound of a four-chime steam-operated whistle,
four whistle-tone-generating oscillators, designated 62a, 62b, 62c
and 62d in FIG. 1, are connected in parallel. By a variable
resistance in each oscillator circuit the basic frequency of each
individual oscillator can be set. Also, the basic tone of the
whistle can be adjusted by altering in five increments the
oscillator-operating voltage supplied by wire 64. Such voltage is
altered by a five-position rotary switch 65.
The amplitude of the combined outputs of the whistle-tone
generators 62a, 62b, 62c and 62d is varied by one potentiometer 66
of ganged potentiometers. The frequencies of the four oscillators
are varied simultaneously by the other potentiometer 67. Both of
the potentiometers 66 and 67 are adjusted simultaneously by
swinging a control lever 68, common to the two potentiometers. Such
whistle-control lever is shown on the stationary control panel of
FIG. 5 and can be swung to provide whistle blast combinations of
various types, such as the typical crossing warning whistle, for
example.
In addition, a controlled amount of audio frequency signal
simulating escaping steam is fed into the whistle component of the
circuit by wire 69 connected to the mixer section 29 and to wire 71
leading to the random noise generator circuit 41. A tone control
and amplification circuit for the hiss and whistle, designated 72,
is interposed in the circuit 71. Such added steam hiss audio
frequency component contributes greatly to the reality of the
simulated steam whistle sound.
In addition, the lever 68 may be manipulated to control escaping
steam sound simulating blowoff of steam occurring when a pop safety
valve opens, or for blowing down the boiler. Such effect can be
accomplished by moving hiss switch 73 from the "off" position to
the "on" position, in which latter position the whistle-tone
oscillators are disconnected from the wire 69 leading to the
audio-frequency mixer section 29 leaving only the steam hiss
circuit connected to such mixer section. By manipulation of the
lever 68 with the switch in this position, the intensity and
duration of the steam blowoff sound can be controlled.
Portable Control
Where the track system for a model railroad is extensive, it is
desirable to enable the sound accessories described above to be
operated by a portable control rather than from the stationary
panel illustrated at the right of FIG. 5. Such a portable control,
which may be called a "walk-around unit," shown at the left in FIG.
5, can be held in the hand by a pistol grip 74. On the body of this
portable control device various control elements are illustrated
which are electrically connected in circuit with the corresponding
controls on the stationary control panel, so that either control
can be manipulated to obtain the desired effect.
Specifically, the portable control device includes the speed
control potentiometer 17W for regulating the speed of travel of the
locomotive when corresponding potentiometer 17 is in low speed
position. Switch 18W can reverse the direction of travel of the
locomotive in whichever position corresponding switch 18 is
positioned on the stationary control panel. The bell can be
energized or de-energized by manipulation of the switch 40W when
the corresponding switch 40 on the stationary panel is in the "off"
position. The sound of the chuff can be regulated by the control
61W, and its volume can be adjusted by the control 45W when the
corresponding controls 61 and 45 on the stationary panel are in
their full on positions. Blowoff of steam or whistle can be
selected by the switch 73W, when the corresponding switch 73 on the
stationary panel is in the "on" position. A whistle or blowoff can
be controlled by pulling the trigger 68W when the lever 68 on the
stationary control panel is in the full on position.
* * * * *