Railway switches and signals – Train-position indication – Miniature model
Reexamination Certificate
2002-01-03
2003-02-04
Morano, S. Joseph (Department: 2837)
Railway switches and signals
Train-position indication
Miniature model
C318S051000, C318S580000
Reexamination Certificate
active
06513763
ABSTRACT:
BACKGROUND OF INVENTION
This invention pertains to the field of control systems for scale model railroad layouts, and specifically to improvements in locomotive decoder (receiver) device interface connections and mode-conversion capabilities.
The advent of Command Control technologies has led to increased enjoyment and capabilities for model railroaders and their operations of model railroad layouts. Since the early Carrier Control systems of the 1970's and up to the latest Digital Command Control technologies, the key capability of all the technologies is the same. This is the ability to control multiple independently addressed locomotives in the same electrical section of model railroad tracks. All the technologies that communicate these addressed commands to a particular receiver, or decoder, in the locomotive by electrical conduction via the rails employ some variant of encoded time-varying voltage waveforms, and are termed Command Control systems. Additionally, some 1990's prior art Command Control systems have been developed that control decoders via a Radio Frequency link or an Infra Red data link, with energy supplied via the track or batteries, and these variants can be also considered to behave in a similar manner and scope to the systems discussed herein. As technology and miniaturization have improved, the encoding methods, features and capabilities have been upgraded, but the net effect is still fundamentally that of allowing multiple simultaneous train control capability in at least a single track-section. This is a capability that no earlier “conventional” AC or DC power-pack systems possessed and is why these older single-control per track systems have been surpassed by Command Control methods.
The earliest GE “Astrac” system was one of the first “frequency modulated” waveform train Command Control systems, along with the methods employed by Lahti in U.S. Pat. No. 4,341,982. In the early 1980's the Hornby “Zero-One” system, as taught by Palmer in U.S. Pat. No. 4,335,381, provided one of the first examples of a modem Digital Command Control, or DCC, system with digital command encoding methods that are direct precursors of the latest message-based Digital Command Control art. Additionally, the Marklin “AC Digital” or Trinary DCC system was also introduced in the mid-1980's, and is taught by Hanschke in U.S. Pat. No. 4,572,996.
The freedom to operate multiple receiver, or decoder, equipped locomotives then raised a further novel question of interchange of and coupling of different technology locomotives on and between layouts equipped with the exciting technologies of, Command Control, Digital Command Control or Carrier Control and other conventional layouts and locomotives without these new capabilities. These different modes of operations are not inherently compatible.
One of the earliest widely known publications to identify this equipment interchange and compatibility issue was by Craig Kosinski in a March 1983 Railroad Model Craftsman magazine article. In this article Kosinski clearly identifies the problem of running the “new” Carrier Control (also often termed Command Control) technology steam locomotives on a conventional DC controlled layout, with other DC controlled locomotives or trains. Kosinski proposes an obvious and simple functional solution to the problem. Kosinski teaches the addition of a double-pole double-throw (two configurations) “changeover” style switch to bypass the receiver, or decoder, and allow the locomotive motor to be fed directly from the track power or energy source. As Kosinski states, this allows “making the control system optional”, and neatly solves the interchange dilemma between different control technology locomotives and layouts. With the decoder bypassed, the motor allows the locomotive to act in tandem and to be safely coupled with other DC motor locomotives, in a wholly compatible manner. The extension of this bypass switch method to be used with locomotives from DCC systems such as “Zero-One” is also noted, along with cautions for incorrect switch settings. Note that in this configuration the two motor leads are switched, each by an individual switch pole, and there are two current carrying positions for each motor lead switch pole. All six leads of the switch are involved in power (or energy) conduction, and the locomotive motor selectively receives energy from either the energized decoder or directly from the tracks, but not both the decoder and the track energy source simultaneously.
The problem of interchange between DCC decoder equipped locomotives onto DC systems, and also the reversed situation of operating DC locomotives on DCC systems, was also addressed by systems based on the public domain NMRA DCC Standards, introduced in the early 1990's, and based on the earlier Marklin “DC Digital” system. In particular, the NMRA DCC technology allowed for automatic, or selectable, Power Mode-conversion options that allowed the decoder to detect that it was connected to a conventional track energy supply, or other control method, rather than a compatible DCC encoded control system. Accordingly when the decoder or receiver detects the tracks being driven by a conventional power system it modulates the H-bridge motor drive circuit so as to supply the input power directly to the motor. The speed of the motor is then mainly controlled by the amount of conventional voltage supplied and is further usefully modified by decoder actions. The NMRA prior art uses the term “mode-conversion” to describe the action of a decoder, or other control device, that detects a change of the nature of the track energy supply it is connected to then allows a change of control action or strategy based on the new type of energy supply.
While in this non-DCC mode-conversion state, the 1990's prior art decoders continue to enjoy useful DCC benefits, such as; Digitrax FX lighting effects like “Mars lights” enabled while in conventional mode by NMRA Configuration Variable CV13, the simulated Braking and Acceleration momentum effects specified by NMRA Configuration Variables CV04 and CV03 respectively, over-temperature and overcurrent protection logic and many other capabilities such as decoder data feedback or transponding.
Since all decoders employ an input-rectifying bridge circuit (to allow locomotive placement or connection to the track in either direction) the motor H-bridge power 95 supplied as the output of this input-rectifying bridge circuit removes the direction control information implicit in the track conventional DC polarity control. The decoder control logic additionally now has to sense the DC polarity of the tracks prior to the input-rectifying bridge circuit and then appropriately modulate the H-bridge motor drive circuit to faithfully reproduce the intended motor and movement direction. This automated mode-conversion or power pass-through and direction determination was also extended to conventional AC control systems. In the 1990's commercial DCC decoders were produced that could sense the higher voltage direction reversing pulse used by Marklin conventional AC power packs to change direction, or the power cycling sequence used by Lionel ZW type of AC controlled locomotives to discriminate the correct direction commanded. In some decoders the programming or switch-configuring of decoder address to 00 (not a unique control address) forces the decoder to remain in the conventional power or energy pass-through control state.
The converse state of operating a DC locomotive on a DCC equipped track was also made possible with the Analog mode “zero-bit stretching” allowed by the NMRA DCC Standard.
The goal of all these products, efforts and technologies employed all through the 1990's was to allow decoder equipped locomotives to operate with compatibility on conventional control systems (and vice-versa) and allow trains and multiple-unit locomotive “lash-ups”, or consists, to be freely formed with a mixture of different technology locomotives.
The ubiquitous presence in decoders of the input-rectif
Morano S. Joseph
Olson Lars A.
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