Patent Application
20110253664
1. Field of the Invention
This invention relates to the field of model trains. More specifically, the invention comprises a model train coupler incorporating an electrically-controlled linear actuator which allows model train cars to be de-coupled using a remote signal.
2. Description of the Related Art
The overriding goal of the components found in a model train system is the faithful reproduction of the operation of a full-size train. The inclusion of sophisticated electronics and the use of Digital Command Control (“DCC”) have allowed a substantial increase in operation realism. One exception, however, is the state of the coupling devices which are used to selectively connect and disconnect the locomotives and cars making up a train.
Most model train users desire to operate the model train “layout” without having to manually interact with the rolling stock (the locomotives and cars). Modern power and control systems allow the user to accurately run the locomotives at desired speeds and with the desired running characteristics. The user is also able to remotely control switch turn-outs, lighting, sound effects, and a host of other features.
In the operation of full size trains it is necessary to move and arrange cars in order to create a desired configuration which will then be attached to a locomotive to create a train. Such operations are performed in switching yards, where numerous individual moves are made by coupling and de-coupling single cars and short groups of cars.
The couplers traditionally used in model trains allow a user to couple two pieces of rolling stock by pushing them together. The speeds required to create a coupling have often been unrealistically high, but at least the “push to couple” feature is functional. An example of a traditional coupler design is disclosed in U.S. Pat. No. 5,620,106 to Storzek (1997), which is hereby incorporated by reference.
The Storzek device also creates a reasonable facsimile of the appearance of a full size train coupler. Its operation is completely different, but this is not visually apparent to the user. The main disadvantage of a device such as disclosed in Storzek is the requirement that the user manually intervene in order to de-couple two pieces of rolling stock.
A manual de-coupling tool is shown in Storzek's
Couplers which may be uncoupled using a remote signal are known in the art. One good example is the KADEE automatic coupler manufactured by Kadee Quality Products Co. of White City, Oreg. This design pivots open when placed in a strong magnetic field. An electromagnet is generally placed beneath the track at a fixed location. The user operates the model train to place a specific pair of mated couplers directly over the magnet. The user then actuates the magnet, which decouples the mated pair.
The KA-DEE type of coupler is obviously limited by the fact that it can only be operated over the fixed position of the electromagnet. This was once an acceptable limitation. However, the advent of the DCC digital communication protocol allows commands to be sent over the rails themselves. DCC commands permit most train operations to be carried out in any location on the model train layout. Thus, the requirement that the de-coupling operation be carried out in one specific location is an undesirable limitation.
It would therefore be desirable to provide a coupler which can be de-coupled using a signal sent over the rails of the model train layout (such as a DCC signal). It would also be desirable for such a coupler to remain compatible with existing coupler designs so that the user is not forced to change every coupler on every piece of rolling stock. The present invention proposes just such a coupler design.
The present invention comprises a model train coupler which can be opened using a remote signal. The coupler design includes an upper arm and a lower arm, both of which pivot around a common axis. The two arms are mounted in a coupler box which is attached to a piece of rolling stock. One of the arms includes a knuckle located outside the coupler box. The other arm includes a latch positioned to open and close against the knuckle. When the latch is closed against the knuckle, a pocket forms. This pocket cooperates with a pocket on an adjoining coupler to create a mated pair of couplers.
The arm including the knuckle has a first protruding lever located on the side of the axis that is opposite the knuckle. The arm including the latch has a second protruding lever located on the side of the axis that is opposite the latch. The first and second levers are configured to provide a gap therebetween—akin to the handles of a pair of pliers. A compression spring is located in this gap, with the compression spring being positioned to urge the two levers apart and thereby urge the latch against the knuckle. A linear actuator is also located in this gap. When an electrical current is applied to the linear actuator, the two levers are pulled together. This action urges the latch away from the knuckle and opens the coupler.
The linear actuator is preferably attached to a decoder located within the piece of rolling stock. The decoder preferably receives signals over the rails—such as a DCC signal. Thus, a signal sent over the rails may be used to open the coupler in any desired location on the model train layout.
Lower arm 12 is an elongated element having lower pin receiver 30 in its middle portion. The lower pin receiver is also sized to receive pivot pin 24. Lower arm 12 has latch 16 on a first end and lower arm 26 located opposite the latch. Latch 16 and knuckle 14 are designed to bear against each other when the coupler is in a closed state. Hence, knuckle 14 includes mating surface 20 which is positioned to bear against mating surface 22 on latch 16.
The reader should bear in mind that the terms “upper” and “lower” (as well as other direction terms used herein) refer to the specific embodiment shown in the view and should not be viewed as limiting. One could—for example, attach the knuckle to the lower arm and the latch to the upper arm. Although changes in the geometry would be required, the device would function in the same way.
The reader should note that the upper and lower levers actually lie in a common plane. The term “upper lever” is used to indicate that the upper lever is connected to the upper arm. Likewise the term lower lever is used to indicate that the lower lever is connected to the lower arm. The upper lever includes a “dogleg” bend which places it in the same plane as the lower lever. Of course, one could provide both levers with a smaller dog leg bend to place them in a common middle plane. These are all design choices.
A spring device is preferably provided to urge the knuckle and the latch toward each other—thereby making the closed position the default state. Several different types of device can perform this function. A torsional spring is one good example. In the embodiment shown in
A linear actuator is provided to urge the upper and lower levers together when the user desires to open pocket 44 by urging latch 16 away from knuckle 14. A “linear actuator” is any device which selectively changes its length. One example is a solenoid. A second example is a lead screw. Because the assembly shown in
The nitinol coil includes end portions designed to engage a slot 34 in each of the levers so that the wire will remain in position. Any suitable retention features may be used and the engagement of the portions of the coil with the two slots is properly viewed as being only one option among many.
Those skilled in the art will know that nitinol displays unusual properties when subjected to an electrical current. The electrical current is preferably regulated to heat the nitinol wire to an appropriate temperature. This causes the wire to contract, thereby pulling the upper and lower levers toward each other (and urging the knuckle and latch apart). When the electrical current is switched off, the nitinol wire rapidly cools and reverts to its original length. Thus, the nitinol wire serves as an electrically controlled linear actuator. The use of a coiled shape is optional. A simple loop of nitinol wrapped around the upper and lower levers (one or more times) could also function as a linear actuator.
Most rolling stock used with model trains is equipped with a coupler box 45—as shown in
Coupler boxes are often equipped with a removable top 46 to facilitate assembly/disassembly. The “top” may be on the top or the bottom of the assembly as it is oriented when attached to the piece of rolling stock.
The coupling and uncoupling of a device using this geometry is well described in the incorporated Storzek patent (U.S. Pat. No. 5,620,106). Specifically, Storzek's
Returning now to
Therefore, when two couplers built according to the present design are pushed together—they tend to couple together. This is true irrespective of the speed of contact (within reason). Thus, two pieces of rolling stock employing the present couplers may be coupled by pushing them gently together—which is similar to the operation of a full size train.
When uncoupling a coupled pair, one can open both couplers by actuating the linear actuator found in each coupler. Of course, it is preferable to provide geometry allowing a coupled pair to be uncoupled by actuating only one of the two members of the coupled pair. As an example, it may be desirable to couple an “active” coupler built according to the present invention with a passive coupler such as is disclosed in Storzek. The knuckle and latch geometry can be provided such that opening only one member of the coupled pair will uncouple the pair. This feature allows the present invention to be used with older technology.
The reader may wish to know some concepts regarding how the present invention can be remotely controlled. The preferred embodiment uses the widely known DCC technology. In DCC, a microprocessor is placed aboard the piece of rolling stock. This microprocessor is included in a device known as a “decoder.” The decoder receives digital instructions transmitted over the rails and performs certain functions as a result.
As one example, a box car can be provided with a DCC decoder and a pair of couplers constructed according to the present invention which are electrically connected to the DCC decoder. Within the DCC system, the box car is assigned a specific identifier. The model train operator uses a DCC “command station” to send DCC commands over the rails. The user can transmit a DCC command directing that only the decoder on board the specific boxcar open its two couplers. Of course, the decoder on board the box car may also be configured to control its two couplers independently.
Using this approach, the model train operator may selectively operate any coupler at any point on the layout. DCC also allows grouping of commands so that a set of rolling stock could have its couplers opened simultaneously.
The reader should bear in mind that DCC is not the only available protocol allowing the use of digital commands over the rails. Numerous other systems are known and the present invention could work with any of them. The invention could also function in an analog format by using a filtering device to supply current to the linear actuator only when a special signal is sent (such as an AC signal on top of analog DC).
Although the preceding description contains significant detail, it should not be construed as limiting the scope of the invention but rather as providing illustrations of the preferred embodiments of the invention. Numerous other permutations and modifications will be apparent to those skilled in the art. As an example, the upper and lower levers need not be aligned with the long axis of the upper and lower arms in order to perform their intended function. These other embodiments are still within the scope of the invention. Thus, the scope of the invention should be fixed by the following claims rather than the examples given.
