My design for a Turnout Actuator

Discuss the prototype and how to model it.
James Walters
Posts: 69
Joined: Sun Jul 11, 2021 12:16 pm

My design for a Turnout Actuator

Postby James Walters » Wed Jan 26, 2022 8:34 pm

Hello everyone,

This is my first post on this forum, and I hope I've put this in the correct place.

I'm very new to P4 and am still finding my way. As I will ultimately have several dozen turnouts to lay, I wanted a simple operating system, which I understood and which I could replicate easily as my track laying progresses.
I have made a couple of videos showing the development of the idea for my YouTube channel, and the idea seems to be generally well received.

I thought I'd post a much shorter video of the basic thing here and would appreciate the thoughts of those far more experienced than me on here.

My best wishes,
James

ps. The servo in the video is being driven by a Megapoints controller, although I think I will eventually be using an Arduino.


User avatar
grovenor-2685
Forum Team
Posts: 3917
Joined: Sun Jun 29, 2008 8:02 pm

Re: My design for a Turnout Actuator

Postby grovenor-2685 » Wed Jan 26, 2022 8:47 pm

That is a nice neat design, I like it.
Regards
Keith
Grovenor Sidings

User avatar
barhamd
Posts: 289
Joined: Sun Jul 20, 2008 2:45 pm

Re: My design for a Turnout Actuator

Postby barhamd » Wed Jan 26, 2022 10:38 pm

I saw your video on Youtube and thought it looked very neat. I went for a very simplistic Turnout operating unit cut from 3 layers of perspex and a simple bracket for the servo.
Image

Which resin are you using and do you think that it will wear ok?

David

James Walters
Posts: 69
Joined: Sun Jul 11, 2021 12:16 pm

Re: My design for a Turnout Actuator

Postby James Walters » Thu Jan 27, 2022 8:19 am

Thank you Keith and David for your feedback.

David, I've printed these in a variety of resins all of which seem to give good results and I don't anticipate wear being an issue. I have incorporated a sealed bearing between the eccentric and the sliding follower which should last forever, and a very light smear of white grease between the sliding parts seems to help with smooth movement too.

James

Terry Bendall
Forum Team
Posts: 2416
Joined: Sun Jul 27, 2008 7:46 am

Re: My design for a Turnout Actuator

Postby Terry Bendall » Thu Jan 27, 2022 10:07 am

A very neat idea James and something different. It looks like some very sound engineering as well. :thumb David's idea is also interesting and shows what can be achieved when positive thinking is applied to a problem. :thumb

Terry Bendall

Alan Turner
Posts: 643
Joined: Sun Jul 20, 2008 4:24 pm

Re: My design for a Turnout Actuator

Postby Alan Turner » Thu Jan 27, 2022 5:30 pm

grovenor-2685 wrote:That is a nice neat design, I like it.


The only problem is the throw is not adjustable.

regards

Alan

User avatar
barhamd
Posts: 289
Joined: Sun Jul 20, 2008 2:45 pm

Re: My design for a Turnout Actuator

Postby barhamd » Thu Jan 27, 2022 5:53 pm

Alan Turner wrote:
grovenor-2685 wrote:That is a nice neat design, I like it.


The only problem is the throw is not adjustable.

regards

Alan


James' design is adjustable, you just make the servo rotate by less than 90 degrees.

David

davebradwell
Posts: 1173
Joined: Fri Jan 18, 2019 3:48 pm

Re: My design for a Turnout Actuator

Postby davebradwell » Thu Jan 27, 2022 7:09 pm

The slide would have to be good, too to prevent it tending to lift the blades in case of clearance. Units of this type fail to hold the blades down. Dare I ask if the thickness of the mounting flange has been chosen to suit a standard screw length? I'd slot the top fixings If I was making it and arrange for the screws to leave a little clearance between the 2 parts so slide can self align with blade droppers.

DaveB

James Walters
Posts: 69
Joined: Sun Jul 11, 2021 12:16 pm

Re: My design for a Turnout Actuator

Postby James Walters » Sat Jan 29, 2022 9:29 pm

The slide action is pretty good. In the video I haven't fitted the shouldered bolts which retain the sliding plate. I've temporarily used M3 set screws and there is a discernible lift (0.15mm), it looks worse in the video. That will be eliminated with the correct fasteners when I've made them.

Yes, the mounting flanges have been sized to take standard screws (M3.5), but the length of which would depend upon the material they were fitted to. In my case 12mm birch ply.

As David has mentioned, the throw is adjustable by the servo controller and/or by changing the off-set of the eccentric.

James

User avatar
barhamd
Posts: 289
Joined: Sun Jul 20, 2008 2:45 pm

Re: My design for a Turnout Actuator

Postby barhamd » Sat Jan 29, 2022 11:37 pm

The traditional way to get vertical adjustment on the blades was to use tube in the turnout operating unit and then solder a wire onto the blade which slots through that tube. The blade height can be adjusted by sliding the wire up and down in the tube until it is exact the right height. I usually then fix them in place by a spot of solder at the bottom of the tube where the wire sticks out. It can be adjusted later if required by reheating.

I think that James' design would use a similar method, but I can't tell what diameter the holes in the operating arm are.

David

James Walters
Posts: 69
Joined: Sun Jul 11, 2021 12:16 pm

Re: My design for a Turnout Actuator

Postby James Walters » Sun Jan 30, 2022 1:45 am

Servo Turnout Actuator.JPG


You are right David, my plan is to use tubes in the sliding element as per the attached picture. In the drawing these have been spaced to coincide with the rail spacing, although I may extend them outwards to drive the ends of the stretcher bar, in which case I'm hoping the blade height will be determined by the stretcher bar running under the stock rails.
I must add, that this is all very experimental, but the movement of the actuator is silky smooth and I am hopeful that it will work well.

One other thing, the attached image shows a previous incarnation of the sliding element. This has been updated with a little hood to keep stray ballast out of the mechanism, not that this affects the function of the unit at all.

All advice gratefully received.

James
You do not have the required permissions to view the files attached to this post.

User avatar
barhamd
Posts: 289
Joined: Sun Jul 20, 2008 2:45 pm

Re: My design for a Turnout Actuator

Postby barhamd » Sun Jan 30, 2022 6:27 pm

I particularly liked the ballast diverting angle on the actuator. Unfortunately on mine if ballast falls down the hole it gets stuck.
David

Mark-Leigh
Posts: 12
Joined: Sat Jul 22, 2017 6:05 am

Re: My design for a Turnout Actuator

Postby Mark-Leigh » Mon Feb 21, 2022 7:44 pm

James

Absolutely Fantastic Design :thumb

Mark

James Walters
Posts: 69
Joined: Sun Jul 11, 2021 12:16 pm

Re: My design for a Turnout Actuator

Postby James Walters » Mon Feb 21, 2022 9:09 pm

Thank you Mark.


Return to “Track and Turnouts”

Who is online

Users browsing this forum: ClaudeBot and 1 guest