The present invention produces realistic train effects which are synchronized with the motion of a model train. In order to understand the operation of the device, it is important to have a basic understanding of the model trains themselves.
Those skilled in the art will know that there are hundreds of different types of model trains in existence, using many different mechanisms. The following presents two exemplary types, though it will be understood that this is a very small sample of the existing hardware. The inventive devices could be applied to virtually any type of model train.
Six driving wheels 22 are present for the model locomotive shown, with three driving wheels being located on each side (Other locomotive types have different numbers of driving wheels, such as 4, 18, 10, 12, or more). For a locomotive having six driving wheels, a side rod 20 links the three driving wheels on each side together. Main rod 18 links cylinder 14 to side rod 20. In an actual steam train, the piston would drive the main rod and ultimately the driving wheels. In the case of the model train, however, the driving wheels are typically driven by an electric motor and the side and main rods are driven by the driving wheels. Valving mechanisms 16 (which can assume many forms) are also driven by the main rod so that they move realistically. The depiction omits additional rods and linkages in the interest of visual clarity. Many model steam engines replicate these linkages—such as Walschaert's valve gear—in great detail.
Synchronization of sounds for a model steam train are particularly important, since actual steam trains make a rhythmic “chuffing” sound as the pistons cycle. Thus, in order to synchronize the sounds, it is important to know the position (and preferably the speed) of the driving components such as the main rod, side rod, and valving mechanisms.
For a diesel model, there are no external moving components like the main rod or side rod for the steam model. However, synchronization with movement is still important. Actual diesel trains make certain sounds when they are just starting, accelerating under load, stopping, etc. It is therefore generally sufficient to know the current speed and acceleration of the model diesel locomotive 30. A variety of sensors can provide such information.
It is possible to place a timing cam on the axle itself.
Of course, those skilled in the art will know that steam trains typically make a “chuff” sound for every 90 degrees of axle rotation. Four cams could be provided in order to create four pulses per revolution. Other means could be used to provide the timing of the second, third, and fourth “chuffs” for each axle revolution.
Other features can be placed on an axle to provide the synchronized signal.
For most model trains, the driving electric motor is directly linked to the wheels. Thus, if one can measure the position and speed of the motor, one can accurately obtain information regarding the position of other components.
There are several ways to monitor an electric motor.
Those skilled in the art will know that there are many similar types of rotary position and velocity sensors, often called “rotary encoders.”
Simpler speed and acceleration values can obtained by sensing the back EMF of the electric driving motor itself. This technique is well known in the field of electric motor control and is discussed in some detail in the incorporated patents. Back EMF sensing may be sufficient to provide synchronized sounds for model diesel engines.
It may be desirable to provide an embodiment which can be retrofitted to older model trains. It is often impractical to modify the axles or motors of such trains. However, a simple switching mechanism may be easily applied.
The reader will thereby appreciate that it is possible to accurately sense the position and velocity of a variety of moving components in a model train. For a model steam locomotive, it is logical to sense the position and speed of the steam pistons and associated linkages. For a model diesel locomotive, it may only be necessary to sense the model's acceleration and velocity as a whole.
Once the timing signal is obtained, the present invention contemplates exporting the signal to an external receiver/amplifier.
Chassis 34 may also include a small speaker labeled in the view as high frequency speaker 70. The size of this device is limited by the size of the model train, so it is typically quite small. It can be used to play train sounds corresponding to the model train's current state (accelerating under load, braking, etc.). In order to do this, the model train often includes memory means and an on-board processor. The on-board processor senses the state of the model train and retrieves the appropriate sound from the memory means, then plays it on high frequency speaker 70.
Of course, as mentioned in the introductory section, the on-board speaker is incapable of accurately projecting many realistic train noises. Real trains produce many low frequency noises, such as the bass rumbling of a diesel engine or the deep “chuff” of a steam train starting a load. The reproduction of such sounds requires a larger speaker.
Referring now to
Receiver/amplifier 72 is located separately and is preferably fixed. It processes the synchronized signal and ultimately emits appropriate synchronized train noises on a sub-woofer 74. Sub-woofer 74 is a relatively large speaker which is capable of producing low-frequency tones. It can preferably also produce significant amplitudes, so that powerful noises (such as the aforementioned diesel rumble) can be made to sound powerful.
The synchronized radio signal can assume many forms. The receiver/amplifier can likewise assume many forms. It is helpful to discuss some of these forms.
If the model diesel locomotive is accelerating under a load, then the on board sensors will measure this fact and the on board sound generation hardware and software will create deep rumbling sounds for the diesel engine. The sound signal is fed to high frequency speaker 70 and played aboard the train (though the recreation of sound will be poor). However, the sound signal is also fed to RF transmitter 68 and broadcast as radio waves.
Receiver 76 receives the synchronized radio signal and converts it to an analog audible frequency signal (typically through demodulation and other known radio techniques beyond the scope of this disclosure). The signal then passes through low-pass filter 78, which removes the higher frequency components.
The signal next passes through power amplifier 80, which provides a suitable amplitude boost before transmitting the signal to sub-woofer 74. The sub-woofer then projects the signal as sound waves.
Returning now to
The radio transmission and processing delays are not perceptible. Thus, the high frequency and low frequency components are perceived simultaneously. The result is much more realistic than using the small speaker on board the model train by itself. As an example, the squealing sounds of braking could be emitted by the speaker aboard the train while the remotely located sub-woofer provides a suitable rumbling sound.
Those skilled in the art will know that the arrangement shown in
The system described can be implemented using digital or analog processing. Analog processing offers the advantage of simplicity. And, synchronized signals from multiple trains can be simultaneously fed to receiver/amplifier 72 and played over a single sub-woofer 74.
Older model trains do not have on board sound generating hardware. For these types it may be desired to retrofit a synchronization sensor, such as shown in
Of course, the receiver/amplifier will be required to perform additional functions since the pulsed signal is not an actual sound signal but rather just a timing pules.
Processor 84 is in communication with sound memory 86. It retrieves suitable steam train sounds from sound memory 86 and synchronizes these with timing signal 82. The synchronized train sounds are then fed into power amp 80.
For this example, all the sounds associated with the train are external to the train. Thus, it may be preferable to provide a frequency splitter 88 feeding the sound signal into a variety of speakers, including sub-woofer 74, mid-range speaker 90 and tweeter 92.
This embodiment can be equipped with multiple channels operating on multiple frequencies. Thus, a model steam engine could be assigned 26.5 MHz and a model diesel engine could be assigned 27.5 MHz. Two appropriately tuned receivers would receive the two timing signals and feed them into the processor. Processor 84 would then retrieve and assign the appropriate train sounds to the appropriate model train.
Other effects can be synchronized with the sound generation as well. Model steam engines have used smoke generators for many years. Those skilled in the art will know that an actual steam train rhythmically puffs smoke rather than blowing it continuously. The advantages of synchronized sound generation can be applied to smoke effects as well. The previously incorporated U.S. Pat. No. 6,485,347 to Grubba provides a good explanation of smoke generation.
If fan motor 94 is rapidly switched on and off (or even reversed), then a puffing effect will be created. The previously described timing signal can be used to control the motion of motor 94. The Hall effect sensor shown in
Although the preceding descriptions contain significant detail they should not be viewed as limiting the invention but rather as providing examples of the preferred embodiments of the invention. Many variations are possible. As one example, although a radio frequency transmitter has been discussed, other types of transmitters could be used as well. The model locomotive will be traveling over a set of conductive rails and will be in electrical contact with these rails. Thus, the transmitter could be configured to transmit the signal over the rails. The receiver would then likewise be configured to receive the signal from the rails. Accordingly, the scope of the invention should be determined by the following claims, rather than the examples given.