Working Semaphore Signalling

[beeman]

Many interesting comments here and some xcellent work produced. I am following the route of memory wire at present,the main reason being accessibility. Perusing the pics posted, it looks like another under baseboard effort if problems arise in the event of trouble. I decided I wanted a signal that could be 'plugged in' to the baseboard from above with a hole the size of the base of the Ratio signals. The mechanism has to pass thro this hole so that it can be removed if maintenance is required as simply as possible. The design I am working on and have so far produced a couple of 'prototypes' is that the signal has a round 'plug' of wood stuck to the signal base, the memory wire actuator being narrower than the plug diameter, so that the unit can be 'plugged' into the acurate hole in the baseboard. So far so good. I have found problems due to some of my signals being made some 20ish years ago that the belcranks broke due to the styrene going brittle with age, somewhat of a challenge producing brass ones to replace, also with the memory wire there are slight variations in the resistance which means each wire must have some form of fine adjustment for the correct current. This may also be due to slight variations in their length. I have deliberated over this but are erring toward a small length of resistance wire, its length adjusted to suit in series with each memory wire. This seems the simplist approach rather than electronic current adjusters. I am working on around 12 or so operating on the layout, The whole supplied from a 3.3v 2A power supply. I'll put some more info on and a pic later if this generates any interest when the prototypes are 'improved' Beeman.

 

I have updated the mechanism of this design as with hindsight and operation there was too much drag. The final design over a number of tries is shown in my reply to Rhubarbs Signalling and lighting on 11-6-2010 along with a pic. In this there is no drag just a straight pull from the Flexinol wire. Beeman.

[beast66606]

I'm not very keen on bounce. Upper quadrant prototye signal arms bounce because there is a shock absorbing spring in the immediate linkage adjacent to the arm. The rest of the wire linkage and the balance weights don't bounce. I think it is unrealistic to have all this lot yanking up and down. Not only that but you are wearing out what is a rather delicate set of linkages prematurely. Just my view!

 

Upper quadrants bounce because the arm drops (freely) back, under gravity, onto the normal stops, the damper is for the off action, which again is controlled by a stop to prevent the arm going over the top - and of course the bounce also depends on how quickly the signalman returns the lever, how free the wire run is etc - upper quadrants on wooden posts tended not to bounce anywhere near as much as their steel posted brethren.

 

I reckon a random bouncer would be the ultimate, sometimes bouncing, sometimes not.

[beeman]

Hoping this topic is still running perhaps my efforts will be of use to aspirees of working semaphores. My main criteria was to make them work, silently if possible and to be able to 'plug' them in to the baseboard rather than struggle underneath,in the event of trouble, also limited positioning due to my wire controlled points system, some 30 odd. I have played around using Flexinol wire to operate Ratio signals, some constructed some 20 ish years ago, and finding that the bellcranks broke due to the styrene going brittle, tedious making brass replacements.The attached pics for the not quite completed signal show the Flexinol wire is part contained within a brass tube, this uses the inners of electrical strip connectors to provide the fixed guide for the tube, soldered to stripboard, similarly the moving end which gives some adjustment for connection to the actual operating wire. The wires as can be seen, were formed to an Omega type loop so as to give a little resilience, and some protection to the mechanism should the Flexinol break, the spring 'exploding' The signal base is glued to the wooden 'plug' which is a nice fit into the baseboard hole. I have made a total of 12 operating arms so far the attached photo of the triple being the most involved. I would think that the design could be modded to perhaps take at least two more. It does not 'bounce', but the three homes on this stanchion work. Costs for the wire are about £10.00 which can be cut to operate 6 signal arms, stripboard and electrical connectors a few pounds, much cheaper than some methods. The Flexinol wire fixed end was on one tied and soldered over to fix it but he other two,and this is the better method, was the small screw and nut soldered to the stripboard, not too much heat mind ot the stripboard is ruined. Hope the pics show 'how to' rather than my description Beeman

[Sugar Palm 60526]

The latest develpoment is thanks to John McCrea. He has produced an etch which folds up into a box shape and accomodates the SG90 servo. The etch will make up into a single or double unit, the latter holding two servos in a vertical position. Furthermore, the units have tabs so that two (or even more) can be stacked together.

 

The concept allows signals to be removable from the baseboard for examination or for safety during layout transport.

 

I'm not privy to the negotiations but I understand that MSE/Wizard Models have been offered the system and are interested.

 

The first picture in the following Fotopic gallery shows the system fitted to a three arm bracket signal:-

 

http://southpelawproject.fotopic.net/c1911507.html

 

Martin Lloyd

[beeman]

Thought I would put update re Flexinol/Nitinol actuator for signals. I found the original design had friction limitations after making a number, the attached diagram being as friction free as possible, The dwg shows a single actuator but could be multiplied up to a possible 5 still using the same size plug,ultimate numbers at the ingenuity of the maker, as many as you like if you can disguise the wooden base board 'plug'. The advantage being able to 'unplug' the signal and actuator from above the baseboard if maintenance is reqd..A single arm still uses an umbrella spoke as the spine,for multiple arms I used stripboard with the umbrella spoke epoxied to give logitudinal strength on the rear side. the dwg.should be easy to understand, but I will describe the spring bit. The Nitinol wire is formed into a small loop thro the brass tubing ferrule. Also the handrail wire passes thro the ferrule. A loop of only 3to4 mm in length is reqd., this is then crimped in the vice to secure. The handrail wire is passed thro the centre of the spring, the nitinol wire loop over one end of the spring. The other end of the spring on to the bent brass panel pin. The wire fitted round the 8ba fixing screw and tensioned so the spring is never fully contracted. Wire under tension at all times. The nut tightened to retain. The Nitinol wire length is about 100 mm for satisfactory movement if operating Ratio signals. Refer to electrical advice parameters for the wire. Sufficient wire for 8 arms can be had for approx £10.00, so more economic than actuators if you have the time/patience to make. Hope this m helps anyone interested, Good Luck Beeman. Posted couplof pics to show some of my signals.

[retiredoperator]

Hi Sugarpalm. All very good,but, I am certain that a shunt Signal rotates 45 degrees anti clockwise to clear, well at least on UK Outline Railways. Best wishes Kevin

[31A]

Hi Sugarpalm. All very good,but, I am certain that a shunt Signal rotates 45 degrees anti clockwise to clear, well at least on UK Outline Railways. Best wishes Kevin

 

 

Depends which railway.  LNER & BR (Eastern Region) standard ground signals rotate clockwise as per the pictures above - the position of the stripe imitates an upper quadrant signal arm.  GW and (I think) LMS ones turn the other way.