Tuesday, January 11, 2011

Modified actuator for servo



Sorry, friends, but I’ve not found any time 'till now to add a proper description to the movie:
Now It’s time!
I always dislike the arched movement given by the “usual” mounting of music wire on Tortoise and Blue Point actuators, mainly ‘cause on the center point of the movement the wire is out for some part and at both end-points is level with the throw-bar.
Additionally I want to be able to mount everything from the track side, as in some point I don’t have comfortable space from under.
So, ( I know I’ve re-discover the fresh water!) here is my solution:
-          take a 1,5 mm diameter brass pipe and cut 1mm + your roadbed deep +  your plywood deep + 2cm (for me means 5 cm )
-          Take the music wire ( flexible 1 mm) and bend it at 90° at one extremity, leaving 1cm to connect to the throw bar.
-          Make a hole in the plywood at 1 cm from the throw-bar and
-          Insert the pipe in the hole and insert the wire in the pipe.
-          Bend again at 90° on bottom side using the end of the pipe
-          Cut the wire at 4-5 cm from the pipe.
-          Solder a little “U” part ( I’ve used a pin used to hold resistors I’ve spare, but … well check your “maybe can be useful in the future”  box for something that can fit your wire and act as support
-          Fit the upper end of the wire into the “U” on the throw-bar.
-          Take your servo – fit a piece of strong double side tape on the larger side, to firmly stick the servo on plywood.
-          Insert the wire in the servo arm and position the servo aligning the motor perpendicular to the pipe ( in parallel with the turnout throw bar. It don’t need to much precision as the movement is ensure by the flexible wire arm.
That’s all, folks! And … it’s working well too. The strength needed to force the points to side rails is ensured by the ample swing of the servo arm ( program it at 150° or more)

1 comment:

Waxy Parsnips said...

looks pretty simple but watching that wire from the servo to the brass tube looks like a potential break. my thoughts anyways!