Model railroad track switch actuator assembly

Abstract

A track switch actuator which has the advantages of slow, smooth realistic operation, small package size that permits hidden installation directly beneath the track switch and unobtrusive, simple design which does not detract from realistic appearance. In fact, the preferred embodiment is sufficiently small to be installed to the bottom of a track switch before the track switch is installed into the layout. In the preferred embodiment of the present invention, a small low voltage DC motor is installed into an elongated ABS plastic extrusion having an elongated radial wall opening. The motor shaft is affixed to a lead screw on which a threaded slider travels from one end to another depending on the direction of lead screw rotation. An actuator arm in the form of a nail-like projection, is soldered or otherwise firmly affixed to the slider exterior so that the projection travels with the slider along the lead screw with the projection extending perpendicularly from the lead screw. The free end of the projection extends into the throw bar of the track switch for switching same with travel along the lead screw.

1 . A model train track switch actuator assembly comprising:
 an electric motor having a shaft;   a lead screw affixed to said shaft for rotation therewith;   a threaded slider engaging said lead screw for travel along said lead screw with rotation of said shaft; and   an actuator arm extending transversely from said slider, said arm engaging said track switch for actuating said switch.   
   
   
       2 . The track switch actuator assembly recited in  claim 1  further comprising:
 a housing having an elongated opening for said actuator arm, said housing containing said motor, said lead screw and said slider and being configured for attachment to said track switch.   
   
   
       3 . The track switch actuator assembly recited in  claim 2  wherein said actuator arm has a free end for extending through an aperture in a throw bar of said track switch. 
   
   
       4 . The track switch actuator assembly recited in  claim 3  wherein said housing is configured for attachment to a bottom surface of said track switch immediately adjacent said throw bar. 
   
   
       5 . The track switch actuator assembly recited in  claim 4  wherein said lead screw is oriented for being parallel to said throw bar upon attachment of said housing to said track switch. 
   
   
       6 . An actuator assembly attached directly to a bottom surface of a track switch of a model railroad layout; the assembly comprising:
 an electric motor having a rotatable shaft;   a lead screw extending from said shaft;   a slider threadably engaged on said lead screw for travel thereon in a direction dependent on the direction of rotation of said shaft; and   an actuator arm affixed in transverse relation to said slider and extending into engagement with said track switch.   
   
   
       7 . The actuator assembly recited in  claim 6  further comprising:
 an elongated cylindrical housing containing said electric motor, said lead screw and said slider;   said housing having an elongated radial opening for permitting said actuator arm to extend to said track switch and to travel with said slider.   
   
   
       8 . The actuator assembly recited in  claim 6  wherein said track switch has a throw bar with at least one aperture and wherein said actuator arm comprises a shaft having a free end extending through said aperture of said throw bar. 
   
   
       9 . A track switch actuator for use with model railroad layouts; the actuator comprising:
 an electric motor having a rotatable shaft;   a lead screw connected to said shaft; and   an actuator arm configured for travel along said lead screw in a direction dependent upon the direction of rotation of said shaft.   
   
   
       10 . The track switch actuator recited in  claim 9  further comprising a slider interposed between said lead screw and said actuator arm and threadably engaged with said lead screw for riding back and forth along said lead screw upon clockwise and counter-clockwise rotation, respectively, of said shaft.