Abstract:
The present invention provides a smoke generator for a model train. The invention allows a toy locomotive to produce smoke as an actual train would, in a puffing pattern. The present achieves its purpose by manipulating the flow of air through a smoke generating housing with a fan and a blocking device.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a smoke unit for a model toy train. The smoke unit described herein produces smoke in a puffing pattern that is characteristic of actual trains. 
     BACKGROUND OF THE INVENTION 
     Thousands of individuals enjoy collecting and operating model toy trains. From the avid collector to the casual hobbyist, all are drawn to the trains, train cars and accessories that include a high level of detail. Ideally, the components of model railroads duplicate exactly their real life counterparts. 
     Steam engines replicas are among the favorites of collectors. Model toy train manufacturers have successfully developed means for producing smoke in a puffing pattern, reminiscent of actual steam engines. Creating a puffing smoke pattern was accomplished through the use of a piston. The piston operated to force smoke out of a smoke unit and create the puffing action. The piston was driven through a linkage connected to one of the toy train wheels. 
     The problem with the piston assembly was its bulky size. This shortcoming became especially acute during the development of replicas of larger steam engines. One of the largest steam engines, the Union Pacific Big Boy, was outfitted with two sets of wheels which acted independently of one another. This is known as an articulated train. The replica, then, was also designed with two independent, articulated, sets of wheels. Incorporating two sets of wheels, in turn, meant that space for the puffing smoke piston assembly disappeared. However, the demand for realism in model locomotives required that the traditional puffing smoke pattern of the steam engine be duplicated. 
     Rather than doing without smoke at all the prior art attached a fan unit to the smoke housing to blow smoke out of the model toy train. The fan however was unable to produce a puffing action and therefore lacked the realism so many model toy train enthusiasts look for. The present invention provides an inventive solution to the problem of the prior art. 
     SUMMARY OF THE INVENTION 
     The present invention relates to a puffing smoke unit for a model toy train. The unit includes a smoke generator including an exhaust hole and a fan operative to create a flow of smoke from the smoke generator out the, exhaust hole. A blocker intermittently restricts the flow of smoke through the exhaust hole to create a puffing action. 
     The present invention also relates to a method of creating a puffing action in a model toy train which includes providing a fan and a smoke generator. A stream of smoke is generated from the smoke generator which is intermittently obstructed to create a puffing action. 
     It is to be understood that the flow of smoke may be restricted in a variety of fashions including both blocking plates and valves. The blocking mechanism can operate at a constant rate or at a rate proportional to the speed at which the model toy train is traveling. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an isometric view of an embodiment of the present invention having a fan in a housing. 
     FIG. 2 is an isometric view of an embodiment of the present invention having a conduit. 
     FIG. 3 is an isometric view of an embodiment of the present invention having a fan in the smoke generator. 
     FIG. 4 is an isometric view of a smoke puffer unit including a solenoid. 
     FIG. 5 is an isometric view of a first preferred embodiment of the present invention with the blocker in a closed position. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     With reference to the FIGS. 1-4 wherein like elements are numbered alike there is shown a fan driven puffing smoke unit. The present invention creates a puffing action with a fan driven smoke unit by periodically obstructing the air flow created by the fan. Preferably the air flow is obstructed with a blocker plate. It is to be recognized that the air flow could be periodically obstructed with something equivalent to a blocker plate, for example a blocker valve. 
     With reference to FIG. 1, there is shown a puffing smoke assembly including a smoke housing  10 . Smoke housings are well known in the art. Tamura, shown as container  2  in U.S. Pat. No. 4,374,038, and Seuthe, et al., shown as container  4  in U.S. Pat. No. 3,891,826, provide two examples of smoke housings which are both incorporated herein by reference. The smoke housing  10  may be made out of any material, however the material must be able to withstand the process by which smoke is created. Tamura teaches a smoke housing whereby smoke is created by heating a mixture of oil and water to boil. The present invention may be used with any of the methods of smoke generation currently known or subsequently developed. 
     Smoke housing  10  is breached by two holes, an exhaust hole  12  and an intake hole  14 . Exhaust hole  12  and intake hole  14  facilitate an airstream  16  through the smoke housing  10 . Preferably a fan  18 , shown schematically, operates to create airstream  16  and draw air through smoke housing  10  to force smoke out exhaust hole  12 . As air flows through smoke housing  10 , the smoke generated within smoke housing  10  is emitted. The smoke joins ambient air. Preferably exhaust hole  12  is located on the top surface of the smoke housing  10 , near or adjacent to a smoke stack of a model toy train (not shown). 
     Fan  18  may be powered by a direct current or alternating current and may be located within smoke housing  10  or adjacent thereto. Alternatively, fan  18  may be encased in a fan housing  20 . Fan housing  20  may be positioned in either of two positions relative to smoke housing  10 . Fan housing  20  may be positioned upstream or downstream from smoke housing  10 . The stream refers to the direction of the airstream  16 . Fan housing  20  may be joined to smoke housing  10  so that the housings  10  and  20  may be packaged together. 
     Fan  18  assists in the emission of smoke from the smoke housing  10 . For example, if fan  18  is located upstream from the smoke housing  10  with respect to airstream  16 , then fan  18  will act to force air into smoke housing  10  through hole  14  which will force smoke out of smoke housing  10  through hole  12 . Alternatively, if fan  18  is positioned downstream from the smoke housing  10 , then the rotation of the fan will draw smoke and air out of the exhaust hole  12  located on the smoke housing  10 . 
     As shown in FIG. 1 a blocker plate  22  functions to manipulate the airstream  16  by restricting the flow path. Total restriction is not required by the present invention. The blocker may be a plate or valve. In one embodiment the blocker  22  is illustrated as a plate. Blocker  22  interrupts airstream  16  and allows smoke to accumulate in the housing  10 . When airstream  16  is no longer obstructed the accumulated smoke will be forced out creating a “puffing” affect. 
     Blocker  22  intermittently restricts airstream  16 . In the preferred embodiment the frequency that blocker  22  obstruct airstream  16  is directly proportional to the speed at which the model toy train is traveling. The faster the train is moving the faster blocker  22  will actuate. Although it is understood that the present invention is not limited to any particular frequency and the blocker may operate at a constant rate or an arbitrary rate. 
     Blocker  22  may be positioned either upstream or downstream of the smoke housing  10 . In the first embodiment as shown in FIG. 1, blocker  22  is engaged and disengaged through the use of a lever arm  24 . Lever arm  24  is connected to a cam  26  which is positioned on any axle  28  of the model train. As the axle  28  rotates, cam  26  forces lever arm  24  up and down thereby actuating blocker  22  to obstruct the intake of fan housing  20 . By actuating blocker  22  with a cam driven by an axle  28  from the model toy train, the frequency at which blocker  22  operates is directly proportional to the speed at which the model toy train is traveling. However, present invention is not limited to any particular mechanism and it is understood that other mechanisms could be used, for example a biased weight as shown in FIGS. 2 and 3 or a solenoid as shown in FIG.  4 . 
     The present invention creates the puffing effect in the following way. Blocker  22  engages to restrict the airstream  16 . While blocker  22  is engaged, the fan  18  continues to operate. If the blocker is engaged upstream of fan  18  and the smoke housing  10 , the operation of the fan  18  will create a partial vacuum. When blocker  22  disengages, the presence of the partial vacuum will cause a short, relatively stronger burst of airflow. This increased flow creates a “puff.” If the blocker is engaged downstream of fan  18  and smoke housing  10 , the operation of fan  18  will cause the air pressure within fan housing  20  and smoke housing  10  to rise. When blocker  22  disengages, the quantity of air under higher pressure will rapidly expand. This expansion also creates a “puff.” 
     FIG. 2 illustrates a second preferred embodiment of the present invention which includes a conduit  30 . Conduit  30  may be any length, shape or cross-section. As shown in FIG. 2, conduit  30  may be utilized to house a blocker  22 ′. As shown in conduit  30  extends from the exhaust hole  12 . Although it is understood that conduit  30  allows fan  18  or smoke housing  10  to be placed anywhere within the train body. Conduit  30  thus provides valuable flexibility in the placement of the smoke housing  10  and fan housing  20  within the train body. As illustrated, conduit  30  extends exhaust hole  12  to the exterior smoke stack of a model toy train (not shown). As shown in FIG. 2, blocker  22 ′ is driven from a lever arm  24 ′. As shown in FIG. 2, Lever arm  24 ′ includes an offset weight  25 . Offset weight  25  biases blocker to close exhaust hole  12 . Air pressure builds to overcome the biasing effect of offset weight  25  and allow a puff of smoke to escape. The preferred embodiment of FIG. 2 creates a constant puffing pattern regardless of the speed of the toy train, so long as the fan speed is constant. 
     FIG. 3 illustrates a third preferred embodiment of the present invention. FIG. 3 illustrates a smoke housing  10 ″ which has an air intake, and air exhaust on the same side of the unit. Smoke housing  10 ″ includes an integral fan (not shown) which draws air into the housing. As illustrated, blocker  22 ″ is a flapper valve is biased closed by its own weight. The embodiment of FIG. 3 operates in substantially the same manner as that of FIG.  2 . 
     FIG. 4 illustrates a fourth preferred embodiment of the present invention in which the blocking valve is actuated by a solenoid  32 . Solenoid  32  may be controlled in any fashion as recognized by those of skill in the art. Thus solenoid  32  may operate at a constant rate, or may increase or decrease how quickly it operates dependent on how fast the model toy train is traveling. 
     While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claim, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structure as permitted under the law.