Anti Reversal Latch Necessary?

[No1_sonuk]

Is it necessary to have the anti reversal latch in the gearbox?

If, for instance, I can GUARANTEE that the cycle completes every time the gun fires, would there be a problem leaving the latch out?

[jagillham]

Re: Anti Reversal Latch Necessary?

If you could there would be no need. But, it's pretty much impossible to do! Plus, there is no real advantages to be gained from removing the ARL.

[Tiercel]

Re: Anti Reversal Latch Necessary?

This has been asked loads of times...

Ive never yet understood why people feel the need/want to remove the ARL O_o

[SAS Scott]

Re: Anti Reversal Latch Necessary?

most of the time imo is because it always causes problems when closing the gb .
but im just a retard so i find everything hard : D

[No1_sonuk]

Re: Anti Reversal Latch Necessary?

If you could there would be no need. But, it's pretty much impossible to do!

If a piston sensor is used with a MOSFET controller, a completed cycle can be guaranteed.

most of the time imo is because it always causes problems when closing the gb .

This. Plus the GB would be a bit quieter

[richardy]

Re: Anti Reversal Latch Necessary?

yup would be quieter, its how the ptw has the unique sound that it does. Less working mechanical components is always an good idea. But a reliable sensor system is hard to do. The easyest way is simply installing an ascu, or revolution.

Theres nothing more effcient and predictable than garrentying the gearbox cycles the same distance every time. There have been a few custom options, but nothing as a viable product for the masses until the ascu.

The stnadard gb, is basically like a boat in how it stops. Once the cut off lever engages, and breaks the circuit, you have to sit and wait for momentum to stop the gears. Even with adding ab, which (has its own wear issues) its still not garrentyiing where on the gb the gears stop, only that once you release the trigger its instant. To a point its good that it doesnt stop instantly what you want is the power to cut just after release of the piston, then the gears will coast and when it reaches the first tooth it will simply stop as it hasnt to the power to pull it. Trigger blades to close together or later or low cut off lever and youll get a delayed deactivation, the extra power will push it into the next cycle and if power cuts then the pistons in a half retracted state, and the anti reverse latch has had to engage to prevent it unwinding. its the 3/4's cocked position in this situation on a low power gun or one with tooo much over run which cuases lock up on v2 due to the design of the cut off and gears.

hence the reverse latch being needed as it cant garrenty 100% it will always land in an uncocked state. Which prevents the piston reversing and the gears. On some / most cut off levers they will only go one way. At speed this could cuase wear or a jam or damage.

[No1_sonuk]

Re: Anti Reversal Latch Necessary?

I'm an electronics engineer, and am thinking about a custom-build microcontroller/MOSFET with a sensor in the spring guide that senses when the piston is released. The motor would be switched off only after the piston is released.

My primary use for this setup would be semi-locking a full auto capable GB, such as an M14.

[richardy]

Re: Anti Reversal Latch Necessary?

well the m14 is about the easyest gb ever to lock to single only with out the need for any qualifications in electrics. So if thats your goal here id aim higher. Theres many routes which ever one you take will need a micro controller and associated programming tools. The hard part is getting and understanding any results you get from which ever sensor you use. Ie, magnatisim, or sound or optical. A popular route is magnat on the gear or like you say spring guide or near and in the piston. The hall affect sensor doesnt have to be too close its like i say the interpretation of the results and how and when it acts on it thats key.

Most people stop here as the next step is investment of cash on a prototype setup. The controller and its program will be key.

[North West Outpost]

Re: Anti Reversal Latch Necessary?

I was going to say that it may be better with a sensor on the sector gear...Then remembered thats been done, read about that a while ago.

Now thinking about a sensor on the spring guide, with a reciever in the gear box case....So pull the trigger and make contact...Wizzzz....sector gear pushes the piston back breaking the beam still sending power to the motor....Sector gear release tooth does it thing and whoosh...piston shoots forward allowing the beam to be made and cut power. Would need something to give assisted breaking.

The circuit would need to reset each cycle but doable. You could probably use some mosfet technology to give the full package.

But that is on the surface a very good idea.

Getting it to work properly may well be another matter...

[No1_sonuk]

Re: Anti Reversal Latch Necessary?

I mentioned semi-locked M14 as it's the route to M1 Garand.

I already have the microcontroller stuff needed, and have made several devices, including a radio-controlled 3-servo hexapod. Currently working on RS232 remote control for a professional DVD player. PIC microcontrollers are not a problem for me.

Hall effect is one I was thinking of. I saw somewhere a while ago someone had experimented with fitting a magnet to the piston head, with a hall sensor in the spring guide.
Another thought is a retroflective IR sensor in the spring guide. This idea is more prone to fouling by grease, but would be easier to fit as it wouldn't involve opening the gearbox (assuming the spring guide has a through hole).

The biggest problem I'm finding is getting hold of a motor/gearbox assembly to experiment with, and I'm not about to start in on one of my serviceable guns until I know it will work. It appears the only option is importing, or buying a cheap gun to hack, neither of which is particularly appealing.

[jagillham]

Re: Anti Reversal Latch Necessary?

Theres nothing more effcient and predictable than garrentying the gearbox cycles the same distance every time. There have been a few custom options, but nothing as a viable product for the masses until the ascu.

Here lies the problem. The theory is there, and still the ASCU does require the ARL. The overspin and subsequent unwinding of the gears causes double feeding.

[richardy]

Re: Anti Reversal Latch Necessary?

the ascu works fine untill i see other wise, ive not heard any reports, and *** **** wouldnt have endorsed it if it didnt work. It states in the manual you need to remove the ar latch. You have to understand just because it has spin back doesnt make it bad if that spin back is planned and performs a function.

If your good with the pics you should be sorted. Check the forum for a cheap gearbox and motor, buy a cheap handle. Your going to need to build it into a stand, then cut un needed areas out of the gear box casings, for a better view of finishing position of the piston and gears, £40 not a big cost really plus some dremel time. Max £50, and its cheap really for the development stage. A bit of effort in the starting stage will help in the long run.