Peco turntable latching mechanism

[sjp23480]

I have a couple of Peco turntables that will be located in a hidden storage facility with limited access. 

 

I have been scouring the forums to find a reliable and affordable mechanism for aligning the entry/exit roads. Installing commercially available drive systems with indexing being cost prohibitive. 

 

I have the Expo drives, based on the Clearbox motor. Noisy and robust, not terribly refined but reasonably affordable!  One issue is the amount of free play in the deck which causes it to bounce out of alignment during use. 

 

I have devised what I hope will be a reliable latching system using a length of phosphor bronze strip (PBS) and some lengths of plastic strip. 

 

A suitable length of the PBS needs to be folded in half and then bolted to the girder underneath the TT deck, with the V of the fold aligned under the track and protruding beyond the bridge. 

 

The plastic strip should be very thin, I don't know the exact spec but this mine may be 5 Thou and sanded down on one edge.  Cut into short strips, two strips are stuck to the side of the TT well in parallel below each entry/exit road. 

 

As the PBS passes over the first strip and the second latches it in place. With adjustment it is possible to get enough resistance to hold the deck in place but not to stop the motor from turning the deck.

 

Quite difficult to explain, but I hope 

The pictures will make this clear.

 

Would love to hear how others have tackled this problem just in case there is a better solution. 

 

Thanks,

Steve

 

 

[34theletterbetweenB&D]

I suspect that will have poor wear resistance if used intensively. As the edges of the 'notches' on the pit wall round off by the action of the sprung locator, the positional accuracy will degrade. What is required is a self adjusting index that can compensate for wear.  A sprung roller as a locator will perform better: both less rounding off because the roller 'rolls!' into the notch, and then as wear occurs, if the notch is deep enough the roller will sink more deeply and maintain the positional accuracy. (It is advantageous to operate equally in both directions so that wear is as symmetric as possible to keep the location centred where intended. )

 

The above based on automated staging in process and assembly operations transport lines.

[sjp23480]

I agree, and did consider the type of solution you describe but was at a loss as to where to source a sprung roller?  

 

Steve

 

 

2 hours ago, 34theletterbetweenB&D said:

I suspect that will have poor wear resistance if used intensively. As the edges of the 'notches' on the pit wall round off by the action of the sprung locator, the positional accuracy will degrade. What is required is a self adjusting index that can compensate for wear.  A sprung roller as a locator will perform better: both less rounding off because the roller 'rolls!' into the notch, and then as wear occurs, if the notch is deep enough the roller will sink more deeply and maintain the positional accuracy. (It is advantageous to operate equally in both directions so that wear is as symmetric as possible to keep the location centred where intended. )

 

The above based on automated staging in process and assembly operations transport lines.

 

[34theletterbetweenB&D]

For this size, a roller like these on microswitches might do'

https://www.google.co.uk/search?source=hp&ei=9jS8Xpz4Ic24lwSC943YBw&q=roller+actuated+microswitch&oq=roller+actuated+microswitch&gs_lcp=CgZwc3ktYWIQDDoFCAAQgwE6AggAOgQIABAKOgYIABAWEB46BQghEKABOgcIIRAKEKABOgQIIRAVUOrhyQJYhrnKAmCoyMoCaAJwAHgAgAFqiAH0EJIBBDI3LjKYAQCgAQGqAQdnd3Mtd2l6&sclient=psy-ab&ved=0ahUKEwicy5z5tLHpAhVN3IUKHYJ7A3sQ4dUDCAw#spf=1589398048381

[sjp23480]

9 minutes ago, 34theletterbetweenB&D said:

For this size, a roller like these on microswitches might do'

https://www.google.co.uk/search?source=hp&ei=9jS8Xpz4Ic24lwSC943YBw&q=roller+actuated+microswitch&oq=roller+actuated+microswitch&gs_lcp=CgZwc3ktYWIQDDoFCAAQgwE6AggAOgQIABAKOgYIABAWEB46BQghEKABOgcIIRAKEKABOgQIIRAVUOrhyQJYhrnKAmCoyMoCaAJwAHgAgAFqiAH0EJIBBDI3LjKYAQCgAQGqAQdnd3Mtd2l6&sclient=psy-ab&ved=0ahUKEwicy5z5tLHpAhVN3IUKHYJ7A3sQ4dUDCAw#spf=1589398048381

Great thanks, will take a closer look. 

 

Steve

[sjp23480]

On 13/05/2020 at 20:29, 34theletterbetweenB&D said:

For this size, a roller like these on microswitches might do'

https://www.google.co.uk/search?source=hp&ei=9jS8Xpz4Ic24lwSC943YBw&q=roller+actuated+microswitch&oq=roller+actuated+microswitch&gs_lcp=CgZwc3ktYWIQDDoFCAAQgwE6AggAOgQIABAKOgYIABAWEB46BQghEKABOgcIIRAKEKABOgQIIRAVUOrhyQJYhrnKAmCoyMoCaAJwAHgAgAFqiAH0EJIBBDI3LjKYAQCgAQGqAQdnd3Mtd2l6&sclient=psy-ab&ved=0ahUKEwicy5z5tLHpAhVN3IUKHYJ7A3sQ4dUDCAw#spf=1589398048381

Thanks 34tlbB&D, I got hold of some switches and have them installed. Seem to work well, so fingers crossed!  

Steve