ruperty Posted August 2, 2017 Hi, I am trying to model a leg, with a knee and ankle joint, as can be seen in the image with the two motors at the joints. I intend for it to stand up by itself based on the accelerometer reading. However, I don't think the design is very good and would put too much exertion on the motors. I believe a better alternative would be to use worm gears, which I do actually have at the top of the picture to manually change the angle of the accelerometer. So I would like to replace the motor system with a worm gear turned by the motor. However, this is also going to require gears to turn the direction of rotation by 90 degrees. Can anyone suggest the best and most robust way to do this? It would be great if you could let me know what parts would be required for the perpendicular gearage, and the work gearage. I have three Lego EV3 Mindstorms sets. Share this post Link to post Share on other sites
Bostons Brick Closet Posted August 3, 2017 I this at all what you want? Definitely not the best, but something. You can switch out the 2 black bevel gears for 2, 24 tooth gears if you want slower motion. Share this post Link to post Share on other sites
BusterHaus Posted August 3, 2017 If you need the foot and top platform to be parallel at all times add a second set of legs that pivot parallel to the current ones. You can use this classic for inspiration: Motor placement on a pivot point is not ideal - it will limit severely the amount of weight you can lift on the top platform. I would look at using a linkage or a linear actuator to move the two sets of beams. Share this post Link to post Share on other sites
ruperty Posted August 5, 2017 On 03/08/2017 at 3:18 AM, Bostons Brick Closet said: I this at all what you want? Definitely not the best, but something. You can switch out the 2 black bevel gears for 2, 24 tooth gears if you want slower motion. Thanks, yes, that looks pretty cool. Is there a tutorial somewhere that describes the details of building the gearage? Share this post Link to post Share on other sites
Bostons Brick Closet Posted August 5, 2017 1 hour ago, ruperty said: Is there a tutorial somewhere that describes the details of building the gearage? Sorry, I just built it for you, if you want me to I'll make an LDD file but I think you can just copy it from the video. Share this post Link to post Share on other sites
ruperty Posted August 13, 2017 On 05/08/2017 at 3:07 PM, Bostons Brick Closet said: Sorry, I just built it for you, if you want me to I'll make an LDD file but I think you can just copy it from the video. Ok thanks, I'll try and figure it out from the video. Share this post Link to post Share on other sites
ruperty Posted August 15, 2017 On 8/3/2017 at 3:18 AM, Bostons Brick Closet said: I this at all what you want? Definitely not the best, but something. You can switch out the 2 black bevel gears for 2, 24 tooth gears if you want slower motion. Hi, I can't quite make out the gears for the perpendiculation in the video. Is the arrangement in the image suitable? It uses 3 single-bevel 12-tooth gears. Share this post Link to post Share on other sites
Bostons Brick Closet Posted August 18, 2017 On 8/15/2017 at 2:47 PM, ruperty said: Hi, I can't quite make out the gears for the perpendiculation in the video. Is the arrangement in the image suitable? It uses 3 single-bevel 12-tooth gears. I used instead of the 2 single bevel gears, 1 double bevel. Share this post Link to post Share on other sites
ThatOneBuilder Posted August 19, 2017 On 8/16/2017 at 3:17 AM, ruperty said: Hi, I can't quite make out the gears for the perpendiculation in the video. Is the arrangement in the image suitable? It uses 3 single-bevel 12-tooth gears. Its probably better if you remove the back bevel gear and replace it with a half bush.. Share this post Link to post Share on other sites
Carsten Svendsen Posted August 20, 2017 Something like this maybe? I know it's a scissor lift mechanism, but it could easily be modified to what you want Share this post Link to post Share on other sites