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15

Would this solve your problem? Depending on the direction of the input, only one axle will turn.


15

From this image, you can count the teeth well enough to determine there are actually 60 teeth, not 40: This does not appear to be a real part. It also appears you aren't the first to notice this. Jim Brickkeeper had created a ShapeWays model based on this movie piece which I found while searching for LEGO 60 tooth gears. It's no longer available, but it ...


13

Quick answer: LEGO gear module is 1 (metric). See Section 3.4 at this link: http://bdml.stanford.edu/Main/CrawlerNotes The consensus seems to be the following: Lego gears have a metric module of 1, which is the same as a pitch of 25.4 teeth per inch of diameter. Pressure angle is likely to be about 20 degrees. (This is the most common angle with modern ...


13

When your function (such as an extending crane boom) gets to one limit or the other, this clutch gear ratchets instead of binding up the motor and all the gears in between. ETA: Forgot the second question. It has appeared in many sets, most recently the Fairground Mixer.


13

When looking at Blakbird's Technicopedia page for this Technic set, this part is indeed used as a rotary encoder in combination with the bar code scanner. See the last entry on the page.


10

I found CAD files for LEGO technic axles here: https://grabcad.com/library/lego-technic-axles-1 and some gears which have holes for technic axles here: https://grabcad.com/library/lego-technic-gears-1 Using their online viewer I found the following dimensions (Which are a little inaccurate due to the limits of their online viewers tools. For more accurate ...


10

Likely you'll have the differential gears oriented wrong in the front or back section. The differential gear is this piece: Please check the instructions carefully and see if the orientation of this piece in the instruction book matches your build.


9

I'd like to cover two other techniques that work well, they both transmit horizontal torque to vertical but in slightly different ways that I believe may be useful for different situations. Worm Gears Worm gears are fairly small (less than two studs long). Worm gears are designed to be operated in one direction and can only be driven by the axle with the ...


9

The two larger gears were produced from 1970 to 1974, while the smaller gear remained in production for three additional years. There are six sets released during that time that contained all three parts: 800 Gear Set with Motor (1970) 802 Gear Supplementary Set (1970) 803 Gear/Wheel Set (1972) 810 Gear Truck Set (1974) 811 Gear Crane Set (1974) 812 Gear ...


9

These are 3 different versions one the same shape / function that fit over axle. The right one is the oldest from the 80 The left one came next The middle one came after that. To make it more confusing, lego is now back producing the right shape again What I can remember had the original one a lot of clutch power and was hard to be removed. Personal I ...


9

How can I get 2 opposing gear's axles to be perfectly parallel? Are there any good workarounds? You could use an idler gear. It will even out the offset. Yet, at the same time, it (or any odd number of idler gears) will cause both axles to spin in one direction. On the other hand, two (or any even number of) idler gears will not affect the asynchrony of ...


7

If you haven't seen it, Sariel's limited slip differential technique might do what you want, but it's a little different than what you are asking for: This setup doesn't provide a clean way of producing a fixed amount of torque to a wheel if it's partner is running free. It instead simply disables the differential if the wheels have been running at ...


7

According to Sariel's gear tutorial in chapter 5, Efficiency:, - the less gears, the better - the smaller gears, the better Based on this principle the first setup looks the best, but you are right that the 8 tooth gear is the weakest of all and it has the most backlash too, if any of these are valid concerns for your build. Note that gears can be ...


7

If you use a crown gear or bevel gear to connect your gears twice perpendicularly, they are exactly opposing each other, turn in opposite directions, and are parallel (if the respective axle is aligned to the coordinate system of the construction). Like with all gear-to-gear connections, you have a little wiggle room that may exceed half a tooth. If you ...


7

Tl;dr - Your piano appears to be functioning correctly. The step you mention appears to be resetting the gear to a known position. The playback direction is clockwise and free of restriction. The reset process is counter-clockwise and is restricted by another mechanism. For reference, here are the instructions as a massive PDF. It looks like you're ...


6

It sounds like you need a stronger differential. Might I suggest this design by Nazgarot: If you make two, you can build a big and sturdy subtractor like this (probably customizing the gear ratios to your requirements, the right gearing could also remove the need for a PF switch): Here's a video of it in action:


6

Yes, but only one color choice of light bluish gray is available in the default mode.


6

Here's a solution I found in Yoshihito Isogawa's LEGO Power Functions Idea Book Vol. 1 - Machines and Mechanisms: EDIT based on Eric's comment: And here's using the black piece from JohnnyB's tweak:


6

Motor is only being used to operate the crane, not to drive the model. So driving/pushing shouldn't be blocked at any time. I suspect there will be an issue with position of differential - if placed incorrectly both axles will spin opposite directions. And if placed on the ground the model will simply not move. Check steps 169 and 268 in instructions booklet ...


5

It looks like LEGO sells chain and sprockets, don't know if you'd have them lying around though. You could also try using pulleys instead. If you don't have any of the actual pulleys, take the tread off of two wheels and stretch a rubber band across, that should work too.


5

The torque in both versions would be the same. Your first version just adds 3 of these gears: The ratio between them is 1:1 so it will be the same as if you connect the axle straight into those small gears, as you do in the second image. (Well, technically speaking, having 3 more gears in the mix will sacrifice some power to friction, but the theory is ...


5

I felt my original answer got messy. The simplest answer is that you already had it. I experimented with variations of your 12T/24T build and experienced varying degrees of the stiffness you mentioned. It became evident that the location of the gears was affecting how much the side pieces were pinching the gears even though the actual gear mesh remained ...


4

The XL motor runs at approximately 220 RPM. Therefore, the following gearbox from the ELEC 201 class LEGO Design module from Rice should be sufficient:


4

The Technic Riding Cycle theme features several bikes that may be of inspiration. One particular set Moto Cross Bike (42007) uses several 3711: Technic, Link Chain parts to make a chain. Based on Bricklink prices for the last six months, 39 chain pieces (the amount shown in the set above) would cost £4.29 (Aprox. $6.91 or €1.26). Pulleys and rubber bands ...


4

In the case of this item, it means that the gear will slide freely along the axle it rotates around.


4

In this forum thread I have found the following tidbits: "We all know that XL motors can twist axles to their breaking point" This means 40 Ncm, according to Philo. "If you're looking to get max torsional stiffness, then stacked 2L axles + connectors would definitely be much stiffer in torsion than a single long axle." Axles can twist without breaking in ...


4

Seeing a picture of your progress would help tremendously. The way the question is worded, it sounds like you were wanting to drive the beveled gear directly from the servo to the rack at a 90 degree angle. This won't work for two reasons: 1. The majority of Lego racks are not beveled. 2. The rack moves fore and aft as it moves side-to-side, which would ...


4

LDD is a design solution for static models. It is not a functional simulation tool. The gears turn with the crank handle if they are associated to the same group, but that is only because the gears, the axle and the handle share the same rotation point. The toothed bar does not share that same rotation point (and is likely not part of your "group" that ...


4

The LEGO Digital Designer software does not have the ability to simulate the interaction of gears. There is a similar software program called SR 3D Builder that does have this capability.


4

You can't do this with the gears you've listed, but I'm not sure that you've listed the proper gears. I don’t believe that 32 or 64 tooth gears exist. I at least don't have any. You can do this by combining common 8, 16, and 24 tooth gears. The following gives 3:1 × 2:1 × 2:1 × 2:1 = 24:1.


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