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Showing results for tags 'boom'.
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Model of a Mack Granite truck equipped with a boom and flatbed. Features drive, steering, full suspension, motorized boom elevation, extension, and rotation, winch, and extending/lowering outriggers. Functions/features: Drive Steering Full suspension Boom elevation Boom extension Boom rotation Winch Outriggers Instructions available on Rebrickable: https://rebrickable.com/mocs/MOC-150955/JLiu15/mack-granite-boom-truck/#details After the 4-output distribution gearbox on my MCI D4500CT Commuter Coach model proved to be ineffective, I didn't want to simply abandon the gearbox design. I decided that I was going to tweak the gearbox a little to be used in a new MOC. I had wanted to use the same suspension setup for my MCI D4500CT model as a test bed for the suspension design, so I settled on incorporating the gearbox into a truck model. A boom truck like this is a MOC I had wanted to make for quite some time, as I see plenty of them in the US but not that many MOCs of them. Because the turntable for the boom is placed higher up, it leaves more room to route gears/axles from the gearbox to the 4 functions it controls. Because the gearbox sits in the heart of the chassis between the outriggers and rear axles, the chassis is built very densely. The gearbox makes use of two Control+ L motors: one for shifting and one for driving the output functions. The drive motor (a Control+ XL motor) sits directly behind the gearbox, and drive is transferred to the rear axles via an extendable CV joint. The drivetrain is geared down after the CV joint to reduce the amount of torque applied to it. Lastly, there is another Control+ L motor for steering which is built into the front axle. I designed the suspension (a simple live axle for all 3 axles) entirely in Stud.io before building it physically, so I had no idea how it would perform upon building it. However, the entire setup worked flawlessly, and there are no issues with drive transmission into the suspended rear axles. My initial plan for this MOC was to just build it as a generic US-style truck, but upon finishing the cab someone said it resembled a Mack Granite, so I modified the cab to actually make it based on the Mack Granite with the Mack Bulldog emblem from the 42078 Mack Anthem set in the front. A number of metallic silver elements are used in the front, although due to the relatively low number of pieces available in that color there is still plenty of gray in the front (such as the bumper). The Control+ hub is placed in the back of the cab and is removable for battery replacement by removing the roof, as the hub and roof are attached to each other. This means the sides of the cab must be sturdy to compensate for the relatively loosely attached roof, so the doors do not open on this model. I decided to build the cab in dark blue, a color I have not used much before, as I now have a sizeable collection of dark blue pieces from the 42083 and 42154 sets. I built the boom in yellow to contrast with the dark blue cab. The boom is built around 3x19 frames covered with tiles. Their abundance of pin holes makes them a good candidate for crane booms. It was difficult routing the two motorized functions through the turntable and into the boom, as two separate axle functions must pass through a small space. Because only two axle functions can be routed through a turntable, I had to make the winch manually operated with a ratchet mechanism. I was initially concerned about the weight of the boom, and while the boom does tend to lean forward during the elevation process, everything remains intact even at maximum elevation and extension and the range of the boom is quite impressive. There are no stoppers for the boom rotation, so the boom can theoretically rotate infinitely as there are no wires going through the turntable. The outriggers, however, were a weak point for the model as they are quite flimsy and are unable to lift the truck off the ground without substantial bending, so I limited the outriggers' legs extension to where they are able to make contact with the ground. Additionally, I should have geared down the mechanism substantially more, but a modification would require essentially rebuilding the chassis from scratch. As a result, I set the gearbox motor responsible for driving the gearbox functions slightly below maximum speed. I had wanted to be able to control the gearbox functions with a single touch (e.g. pressing one button shifts the gearbox then drives it in a given direction) but was not able to figure it out so I went with a much more straightforward (albeit more difficult to use) controller setup. A single slider is used to drive the gearbox functions, and three buttons are used to shift the gearbox (up 90 degrees, down 90 degrees, and return to one endpoint). I have to keep in mind the position of the gearbox while controlling the model, but the setup overall worked well. Overall, this was a MOC that had plenty of mechanical complexity, but certain functions could've been designed better. While all of the functions work as intended, the boom leans forward quite a bit when the boom elevates and the outriggers cannot lift the truck off the ground. The front axle could've also been reinforced better, as during the steering calibration process the steering pinion gear often skips a tooth. Despite the drawbacks of this MOC, it still largely met my expectations as the drivetrain and suspension worked flawlessly and the dark blue/yellow color scheme worked well. Video: Photos: -
[WIP] Mack Granite Boom Truck
JLiu15 posted a topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
With the gearbox-controlled mechanisms on my MCI D4500CT model proving to be impractical, I did not want to just abandon the gearbox design. Because of this, I decided to incorporate it into a different vehicle. I decided that a boom truck like the following would be god for a four-output distribution gearbox: I have not seen many boom trucks in this style done in LEGO Technic. I've seen plenty of mobile cranes, knuckle boom cranes, etc, but I figured this would make for a unique build, especially as I see plenty of these here in the US. The turntable for the crane is also mounted higher up (at the same height as the roof of the cab), so that'll provide more space for mechanisms. As of right now, the chassis consists of essentially everything to the rear of the wheelchair ramp module on my MCI D4500CT model. A difference is that both rear axles are driven, as opposed to one driven axle and one tag axle. The gearbox outputs will control the outriggers, boom rotation, boom elevation, and either boom extension or winch. There can only be two functions routed through a turntable in order to allow for unlimited rotation, so one of the boom functions will have to be manual. Because the suspension design is identical to that of my MCI D4500CT model, this model will also serve as a test bed for the drivetrain and suspension on my MCI D4500CT model. If everything works well here, I can be pretty confident using this suspension design. Let me know if you have any suggestions for me! Photos: -
Custom boom lift (pnuematic) [moc]
Aventador2004 posted a topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
Oops, @Milan can you close this topic, it double posted itself. Thanks! -
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[HELP] Strong Crane Boom Concept
efferman posted a topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
some of you have maybe seen my video with the of the xl actuator and how the boom is bending under the load. here are two pictures do you have any ideas to prevent this. -
Extreme actuator (long extension)
Tamas Juhasz posted a topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
Hello! I made some experiments nowadays, also this string operated actuator for heavy equipments: http://www.brickshelf.com/cgi-bin/gallery.cgi?f=534220 (this last picture is from another model, just shows the working method) The working pricniple is very simple and effective: the winch in the end of the housing (yellow) pulls out the liftarm construction (gray) with string(s). This isn't realistic, but think about TLC's actuators, they aren't also. I made it for heavy equipment, like crane booms, excavator arms, etc. For raising a big boom, pneumatic has no chance, Lego actuators also. There are two ways after that: custom actuators/custom pieces, or built actuators. I think string is "legal", it can be made also with Lego strings (but would be expensive), so it's 100% legal. The extension is 15 stud (can be a few studs more, but that would be in the "limit zone"). With longer construction it can be even 30 studs (more would cause deflection). I wanted to make it as small as possible, it's 3,8 studs wide, 3 tall. The length can be chosen freely (as long as you want - you just need longer liftarms, or more). The final version in my projects will have bley thin liftarms instead of these black ones, so it will be looking like a real cylinder from a distance. There is 4 paralell strings in this actuator, and at the beginning of the housing there is a little pulley to decrease friction ( http://www.brickshelf.com/gallery/mbmc137/Ideas-Technologies/Extrem-Cylinder/003.jpg ). Strings are very good for smart techniques, this actautor doesn't requires much additional space for motorizing, just make a gearing with a motor after the winch's axle. Of course, you can change the strength of the actuator with stronger/weaker strings. The one in the pictures can create about 100 N of pushing force. This is a bit more than a 10 kg vertical lifting. The backward movement is done by the gravity, but it's not impossible to modify it to pull back the inner part (you can add another string, like 8421's boom extension works). What do you think?