#PDF #paper on #mechanisms for #MEMS #gyroscopes #toread
on 02026-08-26#video on #3D-printing pneumatic logic display #mechanisms (incorrectly described as #fluidics) with FDM and silicone membrane to get 8×8 bistable pixels, which he can play Snake on. Each pixel has a single pneumatic vacuum valve (“transistor”) which permits vacuum to the display only when there is vacuum on both the column channel (providing the air current) and the row channel (opening the valve). To get airtight channels with FDM he prints slow, hot, and overextruded, which still wouldn’t give you the wall smoothness you need for fluidics. The multiplexing is rather slow because he’s driving the rather voluminous channels with solenoid-driven valves, getting speeds more like 8Hz than the 10kHz or so normally achieved with fluidics. The platinum-cured 25A silicone membrane’s smooth surface comes from the air-exposed surface of the silicone in a mold carefully leveled with a 2-dimensional bubble level; he tried using a different, commercially-made silicone membrane for the logic surface, but it had to be smooth and flat on both sides, and the commercial silicone sheet wasn’t smooth enough, so he cast his own with glass as the mold on the bottom side. To get the warped bottom surface of the 3-D print to be flat enough to seal well, he sealed it against glass in a vacuum bag and then annealed the assembly at 60° for several hours. Tiny raised concentric rings around the holes that have to make contact with the silicone membrane hopefully make the system more robust against small deviations from flatness. He 3-D prints Luer lock adapters for standard medical tubing, which connect to the logic board with O-rings. I feel like you could probably Charlieplex with this pneumatic-logic approach, and with silicone you might even get a reasonable lifespan, especially with less extreme flexions than the ones he demonstrates in the video. Amusing note: to speed up display updates, he seems to activate multiple rows simultaneously when their contents are identical, an approach which might work for other kinds of multiplexed #displays.
on 02026-08-24#video on spinning top #mechanisms: it turns out that by spinning an off-center weight inside the top you can get it to keep spinning.
on 02026-08-11#Video of long-running electrical #mechanisms (EZ-Spin motors, etc.)
on 02026-08-11#video of a stone sphere made from “yooperlite”, a granite (or actually syenite, since it contains almost no quartz) with some spectacular sodalite fluorescent crystals (under 365nm UV) included in it, using automatic rock-sphere grinding #mechanisms. #formina
on 02026-08-11#video on #whips made of steel chain that can pulverize pine and cut through fire extinguishers and cheap safes. On one occasion they whipped an aluminum bench so hard that they created a yellow fireball. #mechanisms
on 02026-07-16#video #lecture 12 part 3 on #mechanisms of #flexures. #toread
on 02026-06-17#video #lecture 8 part 1 on #mechanisms of #flexures. #toread
on 02026-06-17#video #lecture 9 part 2 on #mechanisms of #flexures. #toread
on 02026-06-17#paper about spherical #flexures #mechanisms by Jelle Rommers
on 02026-05-08#Leonardo did some initial research in beam theory for #mechanisms; ASME member Roberto Ballarini at CWRU writes, “For the specific case he considered of a rectangular cross-section, [Leonardo] argues for equal tensile and compressive strains at the outer fibers, the existence of a neutral surface, and a linear strain distribution. Of course, [Leonardo] did not have available to him Hooke’s law and the calculus.”
on 02026-05-03#AvE #video disassembling an underpowered Ryobi drill which has a non-cartridge thrust bearing with loose bearing balls. #hardware #mechanisms
on 02026-04-21new #Segerman #video on morphing #mechanisms: morphing between wireframe cubes and octahedra (or generally any two dual polyhedra) with scissor and geared mechanisms. The geared mechanism uses his extensible racks to lengthen or shorten the edges in sync, driven by the edges’ rotation with respect to 12 immobile gears. Also, a demonstration of some Borromean rings at the Institut Henri Poincaré.
on 02026-04-19#video about "supercharged" cyclone dust separator #mechanisms #toread
on 02026-04-11#manufacturing an improved (?) cyclone separator for removing dust from air with #3D-printing. Reports that the clear PVC he used for his outer air duct is much nicer to work with (with a table saw) than other clear plastics. He has a filter bag following these separators in case they don’t catch everything. 95+% of the dust gets caught by the separators. His filter bag has a clear flexible window sewn into it so you can see it fill up! #video #mechanisms
on 02026-04-11Reinier Kuppens and Wolfslag #paper on a #string-based representation for evolutionary design of dynamical #mechanisms. #toread
on 02026-02-18not sure if this page is AI slop but it covers a lot of #mechanisms including planetary roller screws.
on 02026-02-09The #pulser-pump depicted here are not quite just #airlift pump #mechanisms; they’re sort of like a geyser pump in that the riser pipe with the output water reaches below the roof of the compression chamber to dip into the water when the water level is high enough, guaranteeing that the pipe will receive pulses of water even if the air and water fully separate in the chamber. This page credits Charles H. Taylor (who built the Ragged Chutes trompe) with inventing it in 01910, though Practical Engineering claims Cáceres reconstructed it in 01911 from 18th-century descriptions of a miraculous pump at the Alhambra.
on 02026-01-06William W. Priestly built a water pump with no moving parts harnessing compressed air starting in 01888, possibly a #pulser-pump like the one formerly at the Alhambra. “The ram, although credited to Priestly, may have actually been built in 1901–02 by David Hyde. During its construction, a competitor, North Side Irrigation, developed an alternative system and the ram was apparently never used commercially.[5] It was reported to have been functional in 1901.[6]” #mechanisms #history
on 02026-01-06#video by #Practical-Engineering on "pulser pump" water pumping #mechanisms with no moving parts that we believe existed at the Alhambra until the 18th century, recreated by Cáceres in the 20th. The YouTuber here recreated it using acrylic “sheet goods” cut by his friend’s service bureau. He entrains air in the downward flow of water, as in a trompe, and separates the air out of the water at a lower elevation, also as in a trompe. But then he lets the compressed air out of a long riser pipe, and it hasn’t completely separated, so some water is still entrained in it, but less than on its downward trip, so it can raise the water above its initial level. Basically it’s a trompe connected to an #airlift-pump. As with a geyser pump or a #hydraulic-ram pump (also depicted), only a small fraction of the water is pumped upwards. Dean Millar’s paper calls trompes “hydraulic air compressors (HACs)”.
on 02026-01-06#video on tachometer #mechanisms for #machining
on 02025-12-17worthless #Leonardo #mechanisms #video
on 02025-12-17#Leonardo da Vinci #mechanisms #video including odometer, conical ball bearing, worm-gear-driven odometer, etc.
on 02025-12-17#New-Mind #video on #MEMS #mechanisms. Low information content, mostly just stock footage with an inept voiceover.
on 02025-12-17#video of Riley Kolbow’s #worksbydesign chess pawn #mechanisms that transform into each piece, such as a queen. #3D-printing in stainless or plastic.
on 02025-12-16Yes, Wankel really was a militant Nazi. But he invented his engine in 01924, before Nazism. But not before he was an anti-Semite. And, yes, he was expelled from the Party in 01932 because of a dispute with the local Gauleiter, who didn’t want the Hitler Youth to get military training, and did join the SS in 01940, after having been imprisoned for criticizing the Gauleiter for corruption, then freed by Hitler himself. “He was known for his championing of animal rights and opposition to the use of animals in testing.” #mechanisms #history #Germany
on 02025-12-12more #Slocum #mechanisms #lecture #video content from 9 years ago. #toread
on 02025-12-10Alexander #Slocum’s FUNdaMENTALs of Design book and design spreadsheets. The RealPlayer video lectures are no longer online. “Design: Creating something with your mind that frees endorphins.” #mechanisms
on 02025-12-10#video #lecture by Alexander #Slocum on bearings in #mechanisms in a Stars and Stripes do-rag: “In this series of 2.75 videos (named after my MIT class 2.75 Precision Machine Design ) I present the material that is in my on-line free book “FUNdaMENTALs of Design”.
Please also see my website www.ooseh.com where I try to write practical poems to try and help the world be nicer 1/:-( = :-)
(...) As the Pappalardo Professor of Mechanical Engineering, in in late 1990’s I started writing “FUNdaMENTALs of Design” to be a free publicly available design book, and then further developed the material while on sabbatical in 2000 as an Erskine Fellow at the University of Canterbury. (...) Passion, Precision, Pass it on! / Alexander Slocum / Walter M. May and A. Hazel May Professor of Mechanical Engineering / slocum@mit.edu”
on 02025-12-10#Cylo #video on #precision #flexure #mechanisms, starting with “wobble pins” connected with “pairs of notch hinges”, and cascading two springs of different stiffness, so you apply a large displacement to the weaker spring, which produces a small force in the “colinearly attached” weaker spring, which then moves a four orders of magnitude smaller distance. From Smith and Chetwynd. He proposes the “diving board” flexure, where a force on the end of a cantilevered beam produces a small displacement on the opposite side of its fulcrum, the beam being pinned at its end to form the cantilever support with the fulcrum, the displacement ratio being (16/3)L₂(L₂ + L₁)/L₁², thus asymptotically proportional to the ratio of the squares of the lengths, enabling a large transmission ratio in a small package. His realization uses a cross-leaf flexure for the pin, a bearing ball in a screw for the fulcrum, another bearing ball in a screw to bear on the end, and a wobble bar to a four-bar parallel-movement flexure for the output, which he’s measuring with an LVDT. He even has antibacklash flexures on the threads of his screws.
on 02025-12-09#Cylo #video on books about #machining #precision #mechanisms: Richard Moore’s Holes, Contours, and Surfaces, which is largely about operating jig borers; Douglas Blanding’s Exact Constraint: Machine Design Using Kinematic Principles; CRC Press Basics of Precision Engineering, edited by Leach and Smith; Balasubramaniam, Sarepaka, and Subbiah’s CRC Press Diamond Turn Machining: Theory and Practice; Rowe’s Hydrostatic, Aerostatic, and Hybrid Bearing Design; Kittell’s Precision Mechanics; Evans’s Precision Engineering: An Evolutionary View; Smith and Chetwynd’s Fundamentals of Ultraprecision Mechanism Design; Slocum’s Precision Machine Design; of course Wayne R. Moore’s Foundations of Mechanical Accuracy; and Dave Arneson’s blog post listing “50 tidbits”. Smith and Chetwynd is hard to find.
on 02025-12-09Gas pressure regulator #feedback #mechanisms #animation #video
on 02025-10-18#Segerman #video about single-degree-of-freedom deployable #mechanisms that fold up into an icosahedron, made with SLS #3D-printing from nylon
on 02025-10-18#video on “depth charge hydrostatic pistols” (WWII #weaponry #mechanisms #history). Water flowing into a rubber diaphragm inflated it, forcing two concentric flanged sleeves to slide axially apart, releasing the retaining balls inside the sleeves in a groove machined into the firing pin, which the firing spring then slammed through the copper membrane into the detonator. Orifice size determined water ingress speed to approximately set the depth at which the detonator and thus the surrounding booster and finally the entire depth charge would detonate, sinking a submarine. The two sleeves moving in opposite directions makes it shockproof since their absolute position doesn’t matter much.
on 02025-10-17#3D-printing #mechanisms video: an iris, a print-in-place articulated gingerbread man, a magnetic fidget sword, a fidget clicky gear with a spring, two interpenetrating helical halves of a pyramid, a print-in-place planetary herringbone gear fidget spinner, and some kind of silly Oreo thing
on 02025-10-17#video #toread on adding gears to #bicycles with #3D-printing #mechanisms. The script seems to be AI #slop. The single-speed drivetrain design seems to be a useless gimmick with no technical advantage, and it adds a lot of weight to the bike, but the fabrication technique advice seems solid.
on 02025-10-16#video on designing “Static Core” #motors for easy #integration into #mechanisms by making them in the form factor of a pulley, so you don’t need to mount it on the opposite side of a mounting plate from whatever you want to drive, then use a shaft coupler to couple it to another shaft that’s supported on two bearings. Basically the idea is to not have a shaft but just spin the (permanent magnet, so no wires) brushless motor housing, with a timing pulley built onto it. But he didn’t gear the “frameless” motor down enough so his robot can’t overcome static friction to start.
on 02025-10-16#video #toread about voice coil #robotics #hardware #mechanisms from #Breaking-Taps. Inspired by birds. Using Dyneema cable actuation. Glass-filled PTFE bushings, carbon-fiber bones pressed into holes in fittings. He actually gave up on the rolling-contact cable-ligature joints and switched to conventional sleeve-bearing pin hinges. Using voice-coil actuators.
on 02025-10-14#video of #Fraser looking at ancient Greek #automata, replicating a wooden mobile robot described by Heron of Alexandria. He talks through a bit of the #history of the Greek automaton tradition. A weight sinks down into an hourglass, supported by the sand (or in this case seeds) and pulling on cords which move the automaton; the cords are wound around axles, which have pins in them around which the cords can be wrapped to alternate directions of motion, without cam #mechanisms.
on 02025-10-12#video #toread of 41' about #mechanisms and methods for making #automata
on 02025-10-11#video about sand-powered #automata #mechanisms, lifting a bucket of sand with a hole in the bottom until the sand hits a stop. This yields a very predictable, slow motion that can last many minutes, powered ultimately by a spring or weight, originating in Heron of Alexandria’s shrine of Bacchus. Another approach, used in the automaton from 01863 shown in the video, dribbles sand onto a sort of water wheel made of paper, driving it with the weight of the sand itself. In this case the wheel can rotate either direction, and the sand goes directly onto the dead center of the wheel, so the wheel rotates chaotically. The box is sealed with the sand inside, so you can recharge its energy by rotating it slowly in a certain way to get the sand back into the hopper! On some versions, including one made by the channel’s owner, Michael Start of the House of Automata, the mechanism is visible through the clear back.
on 02025-10-11#video #toread about “pretendgineers” and odometer counter #mechanisms.
on 02025-09-25#AvE BOLTR #video about Milwaukee Fuel fencing stapler #hardware #mechanisms, including planetary gear sets, roller clutches, etc.
on 02025-09-25#video of #3D-printing a book of #mechanisms: planetary gears, scotch yokes, a geneva wheel, a belt drive, various linkages, etc.; “Machines in Motion” by AxelMadeIt, with about 70 3-D-printed parts. Unfortunately he added some horrible AI slop doggerel. #manufacturing
on 02025-09-236' #video on #Ibanis-Sorenzo’s wirenut #mechanisms made by #3D-printing: a split screw with a flexure at one end clamps down on the wire when compressed with a conical nut. He calls it a “lever screw” but there’s no levering going on.
on 02025-09-0616' #video by #Diffraction-Limited on an open-source laser interferometer with 100nm #precison over 200mm. He ended up using a US$20 110mW 520nm OSRAM PLT5 520B laser diode with a coherence length over 4 meters, stabilizing its wavelength with feedback altering the drive current. He uses a corner-cube reflector to produce a return beam path offset to avoid backreflection into the diode in his Michelson-interferometer design, and an additional measurement arm (using a glass plate as a double beamsplitter) to provide wavelength/frequency feedback. Voiceover is probably AI text-to-speech. #mechanisms
on 02025-09-06#video #toread by #Murray-Smith about #3D-printing some sort of electric generator #mechanisms?
on 02025-09-06#Technology-Connections #video dissecting an “Aeocky” rotary desiccant dehumidifier, which uses red-hot heating elements, a shaded-pole fan motor for the regeneration air, and a plastic cross-current heat exchanger to regenerate the desiccant and recondense the water. The main desiccant wheel has air forced through it by a large (300mm?) BLDC-like fan. He reports that it’s much smaller than vapor-compression types, the fans only consume about 12W, but the regeneration heating element is 300W, very similar to a vapor-compression device, condensing some 100g of water per hour (11kJ/g water), about ⅕ as much as the refrigerant-based unit. A Peltier-based dehumidifier was about as efficient as the desiccant-based unit in his moist bathroom, but the desiccant-based unit was able to remove water even from the 40%-RH air of his office. Most the ones he found on amazon.co.uk in the US$170–300 range were 580–735W, 7.5–11ℓ/day, and 6–7.5kg, most being almost twice as efficient as the one he tested (≈5kJ/g water). Recommends an adsorption dehumidifier brochure from Technofrigo Tuscany (“TFT dry air solutions”). #desiccants #mechanisms #HVAC
on 02025-09-03#video #toread on ball-joint-based open-source XYZ sub-micron #precision translation #mechanisms using NEMA17 stepper motors and some homebrew magnetic encoders, with 5-arcsecond microstepping in open-loop operation, but using an MT6835 21-bit magnetic angle encoder IC to overcome the hysteresis in the steppers’ laminations and friction. The magnetic encoder uses “magnetic gearing” in the sense that it has 17 permanent magnets with alternating orientations moving past the IC in about a quarter turn, so you get about 68× higher precision (but no absolute readout).
on 02025-09-03#video #toread on #manufacturing a servo-controlled word clock #mechanisms
on 02025-08-31#StuffMadeHere #video of his egg cracker #mechanisms #toread
on 02025-08-30an #Arabic typewriter #mechanisms #patent with only two forms for each letter (using shift) #typewriters #toread
on 02025-08-27VEMAG brand double-screw extruder screw pump #mechanisms pumping M&Ms and ground meat. #video footage of the parts being washed.
on 02025-08-24on Giles Clement #manufacturing watch #mechanisms from scratch in a Brooklyn basement
on 02025-08-23#video of roller/pinion #mechanisms patented in 02019 in Korea and China but denied in Taiwan.
on 02025-08-13the resistance of a shaft to twisting scales as the fourth power of its diameter! #mechanisms #physics
on 02025-08-10#mechanisms for transmitting power such as capstan drives, toothed-belt drives, and strain-wave gears
on 02025-07-24#paper #PDF of “synthetic fiber capstan drives for highly efficient torque controlled robotic applications” from Mazumdar et al. at Sandia, arguing that it’s better than steel cables because plastic ropes can handle tighter bend radii, 8:1 rather than 18:1 in the 3mm range. #mechanisms
on 02025-07-23#video on #mechanisms with unreasonable gear ratios so a tiny little DC motor can lift you
on 02025-06-11#video by #Segerman about expanding racks, an expanding truss made out of telescoping rack-and-pinion #mechanisms. For varying speeds of expansion in different parts of the truss, he can use different numbers of racks, or he can use proportionally different sizes of pinions (making the teeth of the gears larger or smaller).
on 02025-06-11#video on #manufacturing #mechanisms for recycling aluminum cans into flat metal sheets, using two rolling cutters similar to the cutter on a can opener.
on 02024-12-04#video of supposedly “first” geared #CVT #mechanisms. Very complex and confusing. The design is "RatioZero" by Edyson Pavilcu, who is looking for investors. Uses variable lever arms implemented via slots in rotating gears. And apparently a one-way freewheel or ratchet mechanism on other gears (the current design uses a literal clicky ratchet and pawl). But ratchet-based CVTs have been known for a century. This one uses elliptical gears to reduce (but not eliminate) the torque ripple that plagues ratchet-based CVTs.
on 02024-12-01#video #toread of #Uri-Tuchman #manufacturing rose engine ornamental lathe #mechanisms for #machining guilloché
on 02024-12-01Reinier Kuppens’s #video about 50 randomly generated 2-D dynamical #mechanisms, simulated with the Newton–Euler dynamical equations using mass but without friction. Mostly interesting as a demonstration of kinematic diagrams using links, springs, and kinematic couples of type hinge and slider. Up to eleven links if you count ground, except for the last mechanism, which has 17 and falls apart. The links are displayed as rounded polygons in pastel colors with alpha, with a Secchi disk fiducial in the middle. Some of the mechanisms have only one degree of freedom and nevertheless have very complicated movement paths. “Each mechanism is generated by randomly creating a labeled graph from which overconstraints are removed. Then, for all components, parameters are randomly chosen, such as hinge locations and spring constants. The equations of motion are then solved and an animation is created from the resulting timeseries. Everything programmed in MATLAB. More information can be found in this paper: (#stringbased) ... Various numeric integration schemes can be used, but I used the Runge-Kutta 4 method in combination with a [Newton-Raphson] algorithm to fix the constraints after each time step.” #mecheng
on 02024-10-02#video about #3D-printing #flexures #mechanisms with mostly the same standard flexures popularized by BYU that everyone shows.
on 02024-10-02#video about spherical #flexures #mechanisms by Jelle Rommers
on 02024-10-02#video #toread about designing #flexures (37') #mechanisms
on 02024-10-02#video #toread on bending #wire for retainers #mechanisms
on 02024-10-02#video #toread on #wire #flexures about an airpot #mechanisms
on 02024-10-02#video #toread #Disney-Research on kinetic #wire character design #flexures #mechanisms
on 02024-10-02#video #lecture 9 part 1 on #mechanisms of #flexures. Hopkins demonstrates how to analyze serial flexures as combinations of parallel flexures, showing that a bent blade flexure is kinematically equivalent to a wire flexure.
on 02024-10-02#video #toread about #hoarding windshield wiper motors for #mechanisms
on 02024-09-18#video #toread on #Cylo’s thrust air-bearing prototype. #precision #mechanisms
on 02024-09-15#video on #Cylo problems in #precision #optics #manufacturing #mechanisms: “Nanoscale air bearing vibrations cause surface finish issues in diamond turned surfaces.” 50 nanometers of vibration gave a “hazy” surface finish, although you’d think it wouldn’t.
on 02024-09-15#video somewhat poorly explained on #3D-printing #kinematic-coupling #mechanisms for #precision #optics. He shows his optical kinematic mount for a long time without showing what he’s going to use it for, instead trying to explain it in words. He has a green diode laser module mounted in a 3-D printed thingy which is pushed apart with screws (with ground and buffed ends rather than ball bearings as you’d expect) running through soldering-iron-staked brass inserts, pushing on flat stainless steel plates, pulled together with tension springs pulling on bits of welding rod, and pivoting on a 7mm stainless steel ball bearing; all the metal parts are inserted into the plastic framework. I think the idea is that you slide this thing around on a surface and the angle of the laser changes to show you the angle of the surface. The laser module is clamped into the thing with an M4 screw tightening a sort of plastic shaft-collar arrangement around it, and a Powell lens (?) turns the laser beam into a line, which I guess lets you determine the surface’s angle in both dimensions at once? He thanks “Zachary from Breaking Taps” for tips. He’s planning to focus the laser through a spatial filter with a microscope lens to clean up the dirty “cat’s-eye” beam. He’s going to put ball bearings in the base of the mount too, to hold it up (bizarrely, four of them instead of three!), and there’s a screw in the middle to hold it down to a screw hole on the optical breadboard. He's planning to replace the plastic with aluminum or stainless steel. In the comments, @bansci recommends using #OpenFlexure designs and captive nuts rather than heat-staked inserts.
on 02024-09-15#Chronova #video #toread on #manufacturing tiny steam-engine #mechanisms.
on 02024-09-15#Harrison-Low #video about how his #Stewart-platform juggling robot finally can juggle, two balls anyway. He actually did switch from kevlar to #UHMWPE (Dyneema) which I thought wouldn’t handle the friction heat. He shows the pseudo-capstan “hand” #mechanisms that actually throw the juggling ball. Oh, and he's using Zulip instead of Discord to make it more open. #robotics
on 02024-09-15#Harrison-Low #video #toread about redesigning #robotics joint #mechanisms
on 02024-09-15#Harrison-Low #video about eliminating knotted string from his #robotics #mechanisms by wrapping his kevlar threads around screws and then squishing it under the screw heads by tightening them. Maybe he should have just used a trucker’s hitch?
on 02024-09-15#video on designing a clip for a “threadboard” made by #3D-printing, including concerns about layer adhesion, friction, and swivel #print-in-place #mechanisms
on 02024-09-13#video testing #kinematic-coupling with a laser pointer, except they don’t actually test it. #precision #mechanisms
on 02024-09-10#video #toread on #kinematic-coupling mount for a mirror. #precision #mechanisms
on 02024-09-10#video on #manufacturing #kinematic-coupling for air bearings for #precision #mechanisms. #Cylo ground a three-planed vee out of W-1 tool steel to place a bearing ball in, with slots in the sides for access, then hardened and polished it. I wonder why he didn’t just use three bearing balls? He states (incorrectly, I think) that the small contact surface area between the ball and the planes produces lower static friction.
on 02024-09-10#video on #manufacturing #kinematic-coupling #precision #mechanisms with #3D-printing by #Sonya-Vasquez. Using pairs of round metal dowels and threaded balls.
on 02024-09-10"Kiriform" #pop-up deployable #flexures #mechanisms #video showing applications including furniture, luminaires for lighting, zoom lenses, etc. It depends on buckling (and therefore some kind of constraint to keep it from buckling the wrong way) and doesn’t look very rigid. “Deployable structures based on buckling of curved beams upon a rotational input” by Saurabh Mhatre et al.
on 02024-09-10#Segerman #video #toread on braiding gears, based on gripping gears. Insanely ingenious #mechanisms.
on 02024-09-10#Segerman #video: a “flórice,” a sort of flower of cyclide-shaped bananas (made by #3D-printing) that slide smoothly between being a sphere and being a disc, propelled by bevel gear #mechanisms. He calls it “slide-glide cyclides”.
on 02024-09-10#precision kinematic couplings and related work. “Just using the most ordinary quality kinematic hardware will produce repeatability between the two kinematic platforms in the micrometer (40 micro inch) range. By using super stiff cermet component parts with the geometry and surface texture held to the highest possible quality, repeatability in the nanometer range can be achieved.” The micron range is ordinary bearing-ball tolerances, so I suspect that as long as you’re not swapping out your bearing balls, you can get much better repeatability than a micron. Lots of ideas about #exact-constraint design that I wasn’t familiar with! Not very well written, though; lots of repetition. Practical tips: “A complete ball can be economically installed in a kinematic platform by first machining a pocket that is nearly hemispherical. A female cone can be used, but it is much less effective. This pocket is wetted with a high strength epoxy glue, and the ball is clamped in place with enough force to squeeze out the excess glue. Wipe the excess epoxy glue away with some absorbent material wetted with Isopropyl Alcohol.” Unfortunately this advice is repeated almost verbatim in almost every single entry! Also not very reliable; it claims EDM uses an electrolyte, for example. #manufacturing #mechanisms
on 02024-09-09#Breaking-Taps #video about #MEMS accelerometers. He uses a lot of electron #microscopy to show the #flexures and other #mechanisms, then makes macroscopic replicas with #3D-printing. I don’t understand the whole flexure layout, but I appreciate the effort. He says the “gyros” use the Coriolis force generated from resonant vibration, which changes their resonant frequency. I don’t know. #toread
on 02024-09-05#video showing the difference between #geyser-pump #mechanisms and conventional pneumatic ejector pumps #airlift
on 02024-09-04#video showing a very easy construction technique for #geyser-pump #mechanisms using a couple of plastic bottles and a tube. #airlift
on 02024-09-04#video showing how a transparent #geyser-pump works, part 3 of 3. #airlift #mechanisms
on 02024-09-04#video showing how a transparent #geyser-pump works, part 2 of 3. #airlift #mechanisms
on 02024-09-04#video showing how a transparent #geyser-pump works, part 1 of 3. #airlift #mechanisms
on 02024-09-04#video on bending 3mm music wire with a Micro-Mark #60346 Mini Wire Bender tool for radio-controlled #drones #mechanisms (landing gear, pushrods, etc.) For thin wire you can just use heavy-duty pliers. He recommends making Z-bends by first using all three dimensions and then flattening back into two. Basically the Micro-Mark tool is a miniaturized version of a rebar bender. He obviously has a lot of practice because he freehand bends multiple perfect 90° angles, seemingly compensating for the wire’s springback purely by intuition. For cutting the 3mm wire he recommends a Dremel instead of something like a bolt cutter.
on 02024-09-03#video on DIY #mechanisms from 01910, including improvising with tin snips and metal from a computer power supply
on 02024-08-31#video of #Helmke #3D-printing some #mechanisms out of plastic to sort and assemble parts pneumatically with a magazine-fed pneumatic parts feeder for his screws. Sucking them through with a sort of aspirator helped solve some bouncing problems he was having that gave him backwards screws. Finally he wires them together with a CAN bus. #automation #manufacturing
on 02024-08-27#Malawey #video on #precision #mechanisms with #3D-printing: “Borrow a Tolerance!” Lots of wisdom about mechanical engineering and which industrial #manufacturing processes have which drawbacks. He shows a 3-D printed collet as one example of a non-borrowed good tolerance. Demonstrates some 3-D printed springs in I guess ABS, but says you can “borrow a [precision] spring rate” from a spring-steel binder clip, which also doesn’t creep at “any temperature a human can survive”. Borrowing smoothness and toughness from HDPE tubing (from water systems) to make hinges; he sharpens it in a pencil sharpener to get it to go through his #print-in-place hinges more easily. His print-in-place approach has support material between parallel horizontal layers which must be broken free with a spatula or hammer.
on 02024-08-27#video #toread on treadmill crane #mechanisms #history
on 02024-08-26#video by #Steve-Mould on water-powered timers that oscillate using trapped air, a somewhat more complex design than the geyser pump. Super confusing, I don’t understand it. #mechanisms
on 02024-07-31old #video #documentary on #Nitinol #materials showing heat engine #mechanisms at the Lawrence Berkeley Laboratory, by Ridgeway Banks, assisted by Professor McMillan. The video credits Stewart Brand for first drawing attention to it in CoEvolution Quarterly. Looks like about 01975. They were hoping they could convert waste heat into a solution to the energy crisis.
on 02024-07-06#3D-printing #video on #print-in-place #flexures #mechanisms that shoot a toothpick
on 02024-06-10#video playlist #toread on bent #wire #mechanisms “Wire Crafts”
on 02024-06-09#video on bent #wire #cardboard #automata #mechanisms. Shows making crankshafts from galvanized steel wire with pliers, a frame bent around a plastic box using cut bicycle spokes to form loops. Shows how to loop a thinner wire around the crankshaft several turns to form a triangle to prevent the connecting rod from sliding along the shaft. Suggest using kitchen tongs (?), a square pipe, and a sort of clamp for wire bending as well. He mentions copper, “M.S.”, zinc, and solder wire. Demonstrates scribing a plastic box with a sort of improvised height gauge on a normal Formica table, and using a hot wire to puncture it. By godbolerr@gmail.com, Ravindra Godbole.
on 02024-06-09#video on bent #wire #mechanisms. He recommends using a plastic-coated clothes hanger, measuring out bend points in advance with a ruler and permanent marker, using wide-point needlenose pliers, bending entirely from one end, always putting the pliers on the same side of the bend (he’s using the side that has already-bent stuff on it), etc. The half-hour video is entirely about making a crankshaft for driving wire automata.
on 02024-06-09#ThisOldTony #video about toggle #mechanisms (which he keeps calling “over-center mechanisms” for some reason), with an overview of wire flip-top mechanisms, cabinet doors, toolbox latches, boot latches, barrel clamps, suspender latches, vise-grips (“locking clamps”), woodworking toggle clamps, etc. Then he segues into a discussion of living hinges (which he doesn’t name), including bistable designs. #humor
on 02024-06-09#video of enclosed carbon #arc-lamp. He demonstrates an Adams & Bagnall 133-Hz 110-volt 7-amp arc lamp designed for 75 volts across the carbon electrodes, warning that if you run it on lower frequencies its parts may overheat. He does eventually get to showing its workings at about 11 minutes, demonstrating the negative feedback #mechanisms that maintain the arc at the right length. He finally turns it on at 18'45".
on 02024-06-04#TPAI #video on #hoarding high-power junkyard stuff for #jugaad.
Loosely defined; Gerolf’s first “exciting find” is a 35kg transformer with a 200-amp secondary that’s only 5kVA because it’s 50Hz. Seems to be of E-I construction, so it could be a good source of electrical steel, not to mention high-ampacity copper, although his first step is to cut through the 6-kilogram 200-amp secondary with an angle grinder. His objective seems to be to make a kiloamp source for heavy welding, although I’d think a 200-amp secondary would be fine for that. He can’t usefully ohm out the primary because he doesn’t know about Kelvin connections, but he does succeed by measuring the inductances instead. He compares it to a couple of microwave-oven transformers, removing their secondaries and magnetic shunts to replace them with welding cables. 2½ turns on the small MOT can reach 395 amps. The larger MOT (also 2½ turns) reaches 649A. Another transformer he had lying around reaches 666A. 3½ turns on the 5kVA transformer exceeds 1kA, which is the limit of his clamp meter, so he got another one which measured 1200A.
This seems like high current but not high power; an inline-6 Mazda CX-90 is, by contrast, 16.6 horsepower, or 12.3kW, more than twice the rated power of this transformer, and presumably its actual output power is even less when you short-circuit its output through a wrench like this.
He also picked up a handheld spot welder (Dalex-Werke, 380VAC input, 9.2 kg, and various nameplate power ratings I don’t understand including 2.4, 6.1, 10, 2, and 20 kilowatts; I guess 7500 amps is the secondary short-circuit current and should not be multiplied by the nominal 2.3 volt output rating to get 20 kilowatts). He does get it to make some spot welds on razor blades.
He also found a component stereo system (Grundig RT 40 M tuner, Grundig SV 40 M amp, and Dual 1219 turntable) with a fake wooden façade; the tuner capacitor in the radio wasn’t even stuck, and both the radio and the amp from 01967 worked fine! He painted over the ugly fake woodgrain. He had to melt polymerized lubricant off the record player’s speed selection #mechanisms with a heat gun, then scrub it off with WD-40 and steel wool. Also the power switch doesn’t work, and he had to replace the pickup and the center pin. He explains the stroboscopic tachometer at 28'10".
on 02024-05-17#video about improved high-speed linear actuator #mechanisms design using carbon fiber for #Harrison-Low's juggling robot. Now his motor is in the linear actuator itself, and its shaft has two reels on it, one to let out string (kevlar kite string?) and one to take it up, or vice versa when moving the other direction. He’s also added TPU sleeves to the six bearings he was using as rollers to constrain the shaft’s motion to one degree of freedom. I think it's about 500mm of stroke. He’s able to get 3.4m/s and >50k cycles endurance. The theoretical precision is 8.4μm, which is more precise than his ±20μm Mitutoyo calipers, but with a pulley mechanism he got a standard deviation of 57μm, which is pretty good. The string breaks at about 70 or 80 newtons. #robotics
on 02024-04-28#Harrison-Low #video about a #mechanical linear actuator design for a juggling robot, capable of a full 263mm stroke in 100ms. He’s mostly using carbon-fiber reinforced plastic tubes, with six 6001RS cartridge bearings for rollers (one too many for #exact-constraint), held in place by a piece made by #3D-printing, with interchangeable spacers to adjust the fit in 100μm units to the imprecisely-sized tubes. He’s doing the actual actuation with a kevlar-kite-string cable drive, with the cables actually run through teflon Bowden tubes so the motors don’t have to add mass to the actuator joints; the motor pulley has two V grooves for the two ends of the cable. This seems like a good way to do robotic #mechanisms in general. This replaces his first hydraulic design made out of syringes and a second iteration using a ballscrew which was too slow and (I assume) also super expensive. He has an AS5048 magnetic encoder for positional measurement, coupled to the actual moving parts with a constant-force spring, whose rotation is what it measures, but so far he’s just using encoders on the motors themselves (which I guess are brushless since he’s using #ODrive; in fact, the motors are ODrive-branded, model D6374-150KV). He says ODrive's current sensing “completely removes” the need for limit switches. His attempts to clamp the three frame tubes with a flexure from the inside failed, but I don’t know why he doesn’t clamp them with a flexure on the outside, instead relying on hammering them in. He uses a thin wire with a hook bent on the end as fish tape to pull the kevlar string through the teflon Bowden tubes, but doesn’t always need it because of how stiff the kevlar string is. On one occasion the kevlar string was able to friction on the 3-D printed plastic and just cut right through it, presumably from heat (a big advantage for kevlar over UHMWPE, except when you want to cut it; presumably kevlar will creep less for the same reason). #robotics
on 02024-04-28why Wankel rotary engines bankrupt motorcycle manufacturers #mechanical #mechanisms #video. Very nice footage from “@Warped Perception” of a running Wankel engine, then a guy riding a 27hp Hercules W2000 from 01974 West Germany and posing sexily with it on the autumn leaves. Hmm, is it true that the Nazis fired Felix Wankel for being too militant and then he became SS? Yes, yes it is. 8½:1 compression ratio, which I guess is inherent to the geometry. And the Hercules mixed oil into the fuel like a two-stroke. Oh, and apparently insurance companies classified it has having three times the 294cc displacement it actually did, 882cc, presumably because it fires three times as often. That was the first Wankel motorcycle, but then Norton bought the assets and also went bankrupt. Suzuki didn’t go bankrupt but abandoned their Wankel cycle after 12 months, he says. Van Veen went bankrupt.
on 02024-04-04driveshafts #mechanical #video by #New-Mind; how driveshafts, universal joints (pot, Cardan, double Cardan, ball-and-trunnion, Tracta, Rzeppa, tripod, Bendix Weiss, and Thompson types), slip-yokes with splined shafts, and differential #mechanisms found their way into automobiles in #history. Lots of low-value filler footage with a somewhat inept voiceover.
on 02024-04-03#3D-printing 12 tools: a parallelogram center finder (in which M3 bolts for use as pivots cut their own threads) for boards or square tubing; a square-corner center finder for circles or squares; a center finder for a drill press for centering the drill over round stock with a sort of indicator needle, also with a non-self-tapping screw tapping its own hole; a metric screw measuring gauge with both length and diameter, bas-relief labels colored with a sharpie; a similar fillet gauge; a lockable angle gauge for transferring angles; a lockable contour gauge (like a one-dimensional bed of nails, or a pack of cards, as one commenter suggests), with more self-threading bolts, M4 this time, and a cam lever for locking; a sanding block; tiny “paint cones” for supporting objects being spray-painted on points; the THWACK plastic hammer; a flexure-based tube cutter into which you screw a box-cutter blade, which makes “extremely nice flat cuts” on the ends of silicone tubes; a machine vises with a screw clamping mechanism; a Kant-Twist-style clamp. He also calls out things he didn't print, like a Dremel table-saw/disc-sander/shaper mounting, a hand-held drill guide for guaranteeing perpendicular drill movement, etc. #video #manufacturing #mechanisms #teaching-tech
on 02024-04-03rotary #internal-combustion #mechanical engine valves rather than poppet type. It’s a very nice idea, but it doesn’t seal as well, so it’s not used much, though there is a racecar in New Zealand by Ralph Watson called the BSA Racer or BSA Special. Vaztec in the USA is trying to commercialize a rotary-valve design. #video #mechanisms
on 02024-04-03This is the Disney Research paper that transforms rigid linkages into flexure-based linkages: A Computational Design Tool for Compliant Mechanisms, by Vittorio Megaro, Jonas Zehnder, Moritz Bächer, Stelian Coros, Markus Gross, and Bernhard Thomaszewski, 02017 #PDF #flexures #mechanical #mechanisms
on 02022-02-11