Brake system

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Brake system

Postby builder83 » October 15th, 2017, 3:35 pm

My vehicles motor does not require the use of all 8 batteries. I actually exploded one by overloading a 6v motor...

So now I am curious if there are different brake systems that are more accurate than a wingnut hitting a switch since I have batteries available. I could not find any online resources showing any. I was thinking of something like a photogate system that shuts off circuit when wingnut passes by and cuts through light path... but not sure if this would work.

Anybody experiment with other brake systems?

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Re: Brake system

Postby cheese » October 15th, 2017, 6:11 pm

First of all, some sort of sensor based photo gate or something like that would be not allowed unless it was made of 3e. "batteries, wires, motors, switches, resistors, potentiometers & mechanical relays.". I personally think that wing nut is the most accurate in our constraints, just make sure that the switch is activated at the same time as the brakes. Last year for scrambler, my partner and I got to the nearest half millimeter in comp with the wing nut system.
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Re: Brake system

Postby windu34 » October 15th, 2017, 8:06 pm

builder83 wrote:My vehicles motor does not require the use of all 8 batteries. I actually exploded one by overloading a 6v motor...

So now I am curious if there are different brake systems that are more accurate than a wingnut hitting a switch since I have batteries available. I could not find any online resources showing any. I was thinking of something like a photogate system that shuts off circuit when wingnut passes by and cuts through light path... but not sure if this would work.

Anybody experiment with other brake systems?

Would not work
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Re: Brake system

Postby builder83 » October 15th, 2017, 9:03 pm

cheese wrote:First of all, some sort of sensor based photo gate or something like that would be not allowed unless it was made of 3e. "batteries, wires, motors, switches, resistors, potentiometers & mechanical relays.". I personally think that wing nut is the most accurate in our constraints, just make sure that the switch is activated at the same time as the brakes. Last year for scrambler, my partner and I got to the nearest half millimeter in comp with the wing nut system.


Appreciate the response. Makes sense. I also used a wingnut system for my scrambler last year. I am just unsure how a micro switch will work (need to order 1 still).

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Re: Brake system

Postby shrewdPanther46 » October 16th, 2017, 9:31 am

Anyone have advice on how to reduce skidding and get within a millimeter of the target distance consistently using a wingnut microswitch braking method (Other than just trial and error)? Also anyone have any ideas as to what specific microswitch would benefit the vehicle (ex: hinge roller or without)?

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Re: Brake system

Postby cheese » October 16th, 2017, 3:32 pm

So for how it would work, here is a video: https://youtu.be/p9OloEYf81M?t=5m36s.

Make sure your microswitch is normally on, so that when you hit it, it turns it off.
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Re: Brake system

Postby shrewdPanther46 » October 16th, 2017, 5:33 pm

Sorry for being repetitive, but I was really wondering if there was anything that could be done with a wingnut system that speeds up the process of perfection(other than simply trial and error).
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Re: Brake system

Postby cheese » October 16th, 2017, 9:09 pm

shrewdPanther46 wrote:Sorry for being repetitive, but I was really wondering if there was anything that could be done with a wingnut system that speeds up the process of perfection(other than simply trial and error).


Oh I see. Well if you calculate the circumference of your wheel (pi x diameter), thats how far your vehicle will go with one wheel spin. Say it is 25 cm circumference, for 10m, it would be 10/.25 = 40. So have the wing nut in braked position, and spin 40 times from there. It should get you fairly accurate, but you can refine from there. Hopefully you get that.
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Re: Brake system

Postby SPP SciO » October 18th, 2017, 8:40 am

https://www.amazon.com/Linear-Motion-Le ... =350664011 Curious - has anyone experimented with something like this? With the popularity of 3D printers, it's possible to find equipment like this in a variety of sizes. I'm wondering if there's any advantage in precision over a traditional hardware store wingnut/threaded axle system
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Re: Brake system

Postby windu34 » October 18th, 2017, 1:14 pm

SPP SciO wrote:https://www.amazon.com/Linear-Motion-Lead-Screws/b?ie=UTF8&node=350664011 Curious - has anyone experimented with something like this? With the popularity of 3D printers, it's possible to find equipment like this in a variety of sizes. I'm wondering if there's any advantage in precision over a traditional hardware store wingnut/threaded axle system

There probably would be due to better tolerancing, but those setups are way too heavy.
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Re: Brake system

Postby retired1 » October 18th, 2017, 2:11 pm

Stainless or brass threaded rod are normally of better quality than the big box store galvanized all thread. A fair quality tap and die set can clean up that rod very nicely and the tap portion can smooth out the wing nut. They do not have to be expensive. Harbor freight will work quite nicely and you can find a 25% discount coupon in several places. You can get cheap ones in either SAE or in metric. They also sell a combination set, but it will be a bit more.
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I went light on this years prototype and used 4 mm stainless. The problem with that was finding APPROPRIATE gears. 1/8 or 6 mm or 8 mm would have been a lot simpler.
Hard to beat the efficiency of the wing nut set up fo a low cost unit.

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Re: Brake system

Postby shrewdPanther46 » October 24th, 2017, 7:36 am

How do you guys attach the gear to the threaded rod? Do you sand the rod down in one spot?
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Re: Brake system

Postby antoine_ego » October 24th, 2017, 8:38 am

shrewdPanther46 wrote:How do you guys attach the gear to the threaded rod? Do you sand the rod down in one spot?


For consistency, I'd recommend you buy some shaft mounted gears, such as some from Servocity. These utilize a set screw, so you don't have to deal with sanding down the rod to attach it more easily. Make sure you buy gears with the bore diameter you want (usually the width of the threaded rod including threads works fine), and gears with the same pitch to ensure good grip.
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Re: Brake system

Postby cheese » October 24th, 2017, 8:14 pm

My gear is fits almost snug around the threaded rod, so I just sandwich it between some nuts and the crowned portion of the nut centers the gear,
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Re: Brake system

Postby shrewdPanther46 » October 30th, 2017, 10:44 am

just curious, if anyone is willing to share:

Has anyone tried the rubber band wingnut braking system (when you stretch a rubber band across the wingnut parallel to the drive axle to reduce skid)? Does anyone know any other ways to reduce skid?
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