paultownsend wrote:Perhaps the bod who sees it first could copy to here!
andrew jukes wrote:The pictures of the lever locks make me think a solenoid operated version should not be too difficult. Instead of the slotted 'twist to lock' stops, I would think a stop sprung upwards and pulled downwards to release a lever could be arranged. The solenoids would probably need to be staggered so they could be a reasonable diameter, with little rockers to move the stops.
andrew jukes wrote:Going back to the idea of using little solenoids to lock the levers and so simulate a properly locked lever frame, it seems finding suitable solenoids could be difficult.
Pannier Tank wrote:andrew jukes wrote:Going back to the idea of using little solenoids to lock the levers and so simulate a properly locked lever frame, it seems finding suitable solenoids could be difficult.
http://uk.rs-online.com/web/p/dc-d-fram ... d/0347652/
A bit expensive, also as it's a 'pull' type solenoid, it will need some pins turned up to complete.
James Moorhouse wrote:For a description of a model mechanically interlocked frame see this video: clickable Youtube link
The pin is not captive and could possibly be turned down to suit your needs.
paultownsend wrote:...as the solenoid needs only to move its own core and do very little "external work".
Russ Elliott wrote:We used that RS solenoid on Green Street's ground signals. Not sure what the resistance is, but I don't think it is as high as Andrew wants. It is 100% continuous rated though, which would be essential for the lever frame application.
Russ Elliott wrote:paultownsend wrote:...as the solenoid needs only to move its own core and do very little "external work".
If a lever is locked by a wedge-shaped wedge thing (see my earlier sketch), then a reasonable amount of force is needed to keep the wedge up against the sides of the lever sufficient to let the user know that it shouldn't be pulled. (That force could be gravity, or the solenoid in its energised state, depending on what one's view is on what the default/'fail-safe' condition should be.) The solenoid approach appeals because it is instantaneous (compared to the time of a servo), but I suspect the price to be payed will be in amps. A rack of old H&M SM3s would do the job, but the real estate required would be large.
Lever Frame connected to tappets with two holes (Normal / Reverse) for the solenoid pin to lock the levers. The lever catch handle would operate a microswitch which would be connected to the Electronics / Logic Board (in my case a PLC), if the proposed move is valid, the solenoid would energise releasing the lever. Once the catch handle is released the solenoid would then lock the lever again. One solenoid for each lever.
LesGros wrote:James Moorhouse wrote:For a description of a model mechanically interlocked frame see this video: clickable Youtube link
one question arises, who is the builder?
andrew jukes wrote: Paul's thoughts on home-made coils.
My first sketches of a way of doing this would have a locking peg, lightly sprung upwards against a stop, which would prevent movement of the lever just like the servo arrangement sh
On coils, I do have around 20 DPDT relays with 12V 250ohm coils. Pulling one to pieces could be a good starting point for such tests (trouble is, there is much else to do of a far higher priority....)
for electrical simplicity the coil current needs to be kept below 50mA and I suspect a bulkier and higher voltage design (12V would be ideal) would work best.
Hardest job was replacing the plugs supplied on the DYS0201 with molex type connections to connect to the MERG board. These probably cost < £1 and were done in a Pub garden during a meeting of the CHEAG.
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