Can someone help me reverse engenering a Gravity light i need help for creating the wheels and basicaly body of the device and i need people with experience in 3d printing stl format ,it will help alot of people from remote places with no electricity . not just africa or india but also in europe . and is a good tool also for fishing and camping and many other aplications. because the product is very expensive on amazon cost about 60-70 english pounds. so i ask for your help i have everything we need photos of the opened device , patents and all what we need. i need the gear wheel sistem to be done right . thank you for the help. photos with the opened device https://www.ifixit.com/Guide/GravityLight+Motor+Replacement/30798
and patents https://patents.google.com/patent/US20170047810A1/en?inventor=James+William+Reeves
https://patents.google.com/patent/US20120212948A1/en?inventor=Martin+Philip+Riddiford&page=2
First and foremost, using their patents to recreate their product will be a patent violation and a crime, and I will not advise it, but if you live in rural area then I understand your will to make a similar device.
Second, you need a dc electric generator, small enough to be used for the lamp but it needs to be capable of outputing at least 6. volt 0.5-1 A to use it for led lamps and mobile phone battery chargers.
And last, if you have the adequate generator, the only thing you need to make is the housing to hold the gears, and the gearbox with a pulley that lets you convert a slow descending weight to adequate rpm on the generator shaft.
Thank you for the comment Igor and for the concern , i just need the gearbox sistem the electrical generator is not a problem just the gear wheels to make the ratio right . and the weight to be able to pull it back up . i just need the mechanical gearing sistem only. and to be aviable for everybody with a 3d printer.
The gear system is not that hard to make, it is a symple system, also the weight needs to be manualy lifted up, for this to work.
Hi Igor yes for lifting up you need a rachet sistem that go in one way and work free in the other way for lifting up.
If you want to wind the rope up that can be done with a simple handle connected to the rope winding drum.
After the weight drops down, you dissconect it, wind the rope up, and attach the weight again to let it fall freely.
This is the simplest way to make it work.
like in this sketch:
Here is a gearbox design already available on Grabcad. Try searching a bit in the library, chances are you will find something that you can use.
Thank you Tony and Igor for the advice but i need the back enginering of the device i know the composition of the device i am working already on something but if someone is really good at proiecting the gears will be more help ,is already someone who did something very similar but one file is mising from his project and the design is not so prefect made is very lose so i cannot work with that have a look
https://pinshape.com/items/36919-3d-printed-gravbright-gravity-powered-light i need something beter more similar to the original product . thank you .
thanks Igor but i need more than this i know how is made i need someone who know to design beter than me to reverse enginer the design and it needs a Rachet to be able to put it back up or wind it with the hand crank .
Salut Mihai, (for english, see translation in next post)
Calcularea angenajului depinde in mare masura de motorul pe care il ai la dispozitie. S-o luam cu inceputul. In imagine ai un exemplu de angrenaj compus din:
roata rosie: va fi actionata de 3 alte roti, deci pentru simetrie va avea un numar de dinti multiplu de 3 (7*3 =21); daca ai avea 4 roti, multiplu de 4 (x*4). atentie ca exista un numar minim sub care e foarte dificil sa creezi fizic roata dintata (pentru modul 1 circa 12 dinti).
rotile albastre: va actiona roata rosie si trebuie sa fie actionata de roata galbena, avand punctul de tangenta diametral opus, deci va avea un numar de dinti Za =Zr*3*2= Zr*6=21*6=126. Din desen observ ca daca diametru divizor al rotii albastre ar fi 126, dintii celor 3 roti albastra s-ar putea impiedica reciproc, deci trebuie micsorat (cu 2 grupuri de 6 dinti); asta o vezi cel mai usor facand o schita ca cea expusa, stiind ca intre cercurile rotilor albastre trebuie sa ai minim 2 mm. in concluzie Za=126-(2*6)=114.
roata verde: trebuie sa aiba acelasi centru cu cea rosie, si sa fie tangenta la rotile albastre, deci va avea diametrul divizor de 249; considerand modul 1, rezulta Zv=249.
Raportul total al angrenajului este:
intre rosu si albastru: 114 / 21 ~ 5,43
intre albastru si verde: 249 / 114 ~ 2,18
total: 5,43 * 2,18 ~ 11,86.
Cum se calculeaza angrenajul in functie de motorul pe care il ai:
presupunem ca motorul de care dispui are nevoie de RPM = 5 rotatii / secunda pentru a produce 3V si ai vrea sa functioneze minim 15 minute. Asta inseamna ca ai nevoie de 5*60*15 = 4500 rotatii ale rotii rosii; roata verde va avea nevoie de ~ 380 rotatii. Roata verde este corp unic cu tamburul galben. tamburul are un diametru de 100mm, deci circumferinta de pi*100 = 314mm ~ 0.3m.
La configuratia actuala ai avea nevoie de o cadere a greutatilor de peste 100m pentru a avea 15 minute 3V; putin probabil ca este ceea ce vrei.
Cel mai bun mod de a imbunatati raportul este de a conecta inca un ansamblu in spatele celui existent, adica tamburul galben va fi inlocuit de roata rosie a celui de-al doilea sistem. 11,86*11,86~140, inseamna ca noul raport va fi de 1:140. Impreuna cu reducerea diametrului tamburului, depinzand de motorul pe care il ai (rotatii/secunda) si de capabilitatea imprimantei 3D de care dispui, poti ajunge la rezultatul dorit.
greutatile de actionare depind de raportul final al angrenajului, si ca exemplu poti lega o galetusa de plastic si o umpli cu apa pana ce incepi sa obtii curent.
Toata treaba asta e mai mult incearca si vezi, decat a aplica un model deja facut.
Ca fapt divers, un LED are nevoie de 0,7V pentru a incepe sa se aprinda.
Multa bafta!
Cu stima, Florin
Hello Mihai,
The calculation of the gear depends largely on the engine you have at your disposal. Let's start with the beginning. In the picture you have an example of a gear system composed of:
red gear (out module 1, Z = 21) - which will drive the engine; we note the number of teeth with Zr
3 blue gears (out module 1, Z = 114) - we note the number of teeth with Za
green gear (inner module 1, Z = 249) unique part with the yellow drum (the exact diameter we will calculate at the end) on which the string will be wrapped - we note the number of teeth with Zv
red wheel: it will be driven by 3 other wheels, so for symmetry it will have a multiple number of teeth of 3 (7 * 3 = 21); if you had 4 wheels, multiple of 4 (x * 4). attention that there is a minimum number below which it is very difficult to physically create the gear (for module 1 about 12 teeth).
blue wheels: will drive the red wheel and must be driven by the yellow wheel, having the diametrically opposite tangent point, so it will have a number of teeth Za = Zr * 3 * 2 = Zr * 6 = 21 * 6 = 126. From the drawing you notice that if the dividing diameter of the blue wheel were 126, the teeth of the 3 blue wheels could obstruct each other, so it must be reduced (with 2 groups of 6 teeth); you can see this most easily by making a sketch like the one on display, knowing that you must have at least 2 mm between the circles of the blue wheels. in conclusion Za = 126- (2 * 6) = 114.
green wheel: it must have the same center as the red one, and be tangent to the blue wheels, so it will have a dividing diameter of 249; considering mode 1, Zv = 249 results.
The total gear ratio is:
between red and blue: 114/21 ~ 5.43
between blue and green: 249/114 ~ 2.18
total: 5.43 * 2.18 ~ 11.86.
How to calculate the gear according to the engine you have:
we assume that the engine you have needs RPM = 5 rotations / second to produce 3V and you would like it to work for at least 15 minutes. This means that you need 5 * 60 * 15 = 4500 rotations of the red wheel; the green wheel will need ~ 380 rotations. The green wheel is a unique body with a yellow drum. the drum has a diameter of 100mm, so the circumference of pi * 100 = 314mm ~ 0.3m.
In the current configuration you would need a weight drop of over 100m to have 15 minutes 3V; unlikely to be what you want.
The best way to improve the ratio is to connect another assembly behind the existing one, ie the yellow drum will be replaced by the red wheel of the second system. 11.86 * 11.86 ~ 140, means that the new ratio will be 1: 140. Along with reducing the diameter of the drum, depending on the engine you have (rotations / second) and the capability of the 3D printer you have, you can achieve the desired result.
the drive weights depend on the final gear ratio, and as an example you can tie a plastic bucket and fill it with water until you start to get current.
This whole thing is more about trying and seeing, than applying an already done pattern.
As a matter of fact, an LED needs 0.7V to start lighting up.
Good luck!
Sincerely, Florin
P.S. : nice job Google Translate :)
If you don't receive the email within an hour (and you've checked your Spam folder), email us as confirmation@grabcad.com.