Difference between revisions of "Suitable mechanisms"

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This page is basically just a list of mechanisms that <br>
 
This page is basically just a list of mechanisms that <br>
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could be useful for future advanced [[diamondoid]] gemstone based nanosystems.
+
could be suitable and useful for future advanced [[diamondoid]] gemstone based nanosystems.
 +
 
 +
Related page: [[List of machine elements]]
 +
 
 +
= What makes mechanisms "suitable"? =
  
 
Unlike in macroscale machinery with machine parts at the lowermost possible size limit <br>
 
Unlike in macroscale machinery with machine parts at the lowermost possible size limit <br>
−
there is no space for tiny screws that are much more tiny than the parts (housings like gearboxes and such) to clamp together.<br>
+
there is no space for tiny screws that are much more tiny than the functional parts to clamp together.<br>
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Thus there is a need for designs that differ quite a bit from the conventional.<br>
+
<small>(Functional parts is here referring to housings for gearboxes, essential machine element components, and such.)</small> <br>
 +
 
 +
Thus there is a need for designs that differ quite a bit from the conventional macroscale metal part engineering.<br>
 
See the design principles listed on the page: [[RepRec pick-and-place robots (GemGum)]].
 
See the design principles listed on the page: [[RepRec pick-and-place robots (GemGum)]].
  
 
Under the lens of these constrains a particular set of <br>
 
Under the lens of these constrains a particular set of <br>
 
mechanisms/machine-elements emerges as especially promising. <br>
 
mechanisms/machine-elements emerges as especially promising. <br>
−
This page is a collection of such mechanisms.
+
This page features a collection of such mechanisms.
 +
 
 +
== Macroscale side benefit ==
  
 
These mechanisms also allows for interesting 3D printable mechanics that <br>
 
These mechanisms also allows for interesting 3D printable mechanics that <br>
 
can cope without any metal screws whatsoever. A few big 3D printable screws suffice.
 
can cope without any metal screws whatsoever. A few big 3D printable screws suffice.
  
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== Related ==
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= Whole classes of mechanisms =
  
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* Gear-bearings. Peculiarly the '''[[periodic table of gearbearings]]'''
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* Rolling with static friction being absent and surfaces not being flat (atomic bumps) calls for gear-bearings. <br>Peculiarly the '''[[periodic table of gearbearings]]'''
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* The design principles listed on page [[RepRec pick-and-place robots (GemGum)]]
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* Enforced equipartitioned distribution of speed differences over several layers. <br>See: [[Infinitesimal bearing]]s
 +
Related: [[Atomically precise bearings]]
  
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== External links ==
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= External links =
  
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=== Bearings and Gearings ===
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== Bearings and Gearings ==
  
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* '''conical/tapered gearbeaings'''
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* '''conical/tapered gearbeaings''' (with applied pre-tension) <br> '''[https://www.printables.com/model/136844-herringbone-geared-turntable-roller-bearing Herringbone Geared Turntable Roller Bearing by MrCliveMrClive on printables]'''
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* '''conical/tapered ravigneaux gearboxes:''' https://www.flickr.com/photos/65091269@N08/51163799216
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* '''conical/tapered ravigneaux gearboxes:''' <br> [https://www.flickr.com/photos/65091269@N08/51163799216 Sketch on flickr] <br> [https://en.wikipedia.org/wiki/Ravigneaux_planetary_gearset Wikipedia on conventional Ravigneaux gear-sets in general] <br> [https://reprapltd.com/printing-ravigneaux-epicyclic-gearboxes/ More on Ravigneaux on reprapltd]
 
* Wobblemotors: Moineau PCP pumps run partially in reverse with the core only rotating and the outside only wobbling
 
* Wobblemotors: Moineau PCP pumps run partially in reverse with the core only rotating and the outside only wobbling
 
* '''PCP gearboxes''' based on the wobble-motor principle?
 
* '''PCP gearboxes''' based on the wobble-motor principle?
 
* ( Coupled cycloid wobble-rotors like this: https://twitter.com/Kuu3_Mechanics/status/1657680117680979969 – 9,10,11,12 )
 
* ( Coupled cycloid wobble-rotors like this: https://twitter.com/Kuu3_Mechanics/status/1657680117680979969 – 9,10,11,12 )
 +
----
 +
* '''rotative to reciprocative conversion''' via a straight-line-hypocycloid rather than a classical crankshaft mechanism <br> Like this: https://digital.library.cornell.edu/catalog/ss:29272012 <br>Or like this: https://commons.wikimedia.org/wiki/File:Inversion_of_Hypocycloid_Gear_Train_Ellipse_and_Straight-line_Mechanism.gif or [https://www.researchgate.net/publication/328249305_Concept_of_a_pump_for_diesel_engines_fuel_supply_using_hypocycloid_drive]<br> The essence: http://www2.mat.dtu.dk/people/J.Gravesen/MoineauPump/Hypo2_1.html<br>vice versa needs multi-phase drive for defined direction
  
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=== Couplings ===
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== Couplings ==
  
 
* https://en.wikipedia.org/wiki/Coupling#Oldham
 
* https://en.wikipedia.org/wiki/Coupling#Oldham
−
* '''Oldham coupling inspired gear coupling''' <br>Two linear-rack-gearbearings with each two rollers sandwiched atop each other. <br>Their rolling direction is are arranged 90° to each other. Thus they act the same as an Oldham coupling. But with '''rolling rather than sliding'''.
+
* '''Oldham coupling inspired gear coupling:''' <br>Two linear-rack-gearbearings with each two rollers to define a plane. Those two sandwiched atop each other with <br>their rolling direction arranged 90° to each other. Thus they have the same exact effect as an Oldham coupling. But with internal '''rolling rather than sliding'''.
 
* (Schmidt coupling - this needs a lot of pins (ideally gear-bearings) thus listed in the likely unsuitable section further below)
 
* (Schmidt coupling - this needs a lot of pins (ideally gear-bearings) thus listed in the likely unsuitable section further below)
 +
'''CV type joints'''
 +
* Tracta joint: https://en.wikipedia.org/wiki/Constant-velocity_joint#Tracta_joints
 +
* Tripod joint: https://en.wikipedia.org/wiki/Constant-velocity_joint#Tripod_joints
 +
* Double Cardan joint: https://en.wikipedia.org/wiki/Constant-velocity_joint#Double_Cardan <br>Doube cardan is two universal joints that are each individually not CV
 +
* (Rzeppa & Thompson down in the likely unsuitable section)
  
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=== Joints ===
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== Joints ==
  
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* Hirth joints: https://en.wikipedia.org/wiki/Hirth_joint
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* Hirth joints: https://en.wikipedia.org/wiki/Hirth_joint <<< '''these are extremely useful'''
 
* Spline joints: https://en.wikipedia.org/wiki/Spline_(mechanical)
 
* Spline joints: https://en.wikipedia.org/wiki/Spline_(mechanical)
 
----
 
----
Line 47: Line 62:
 
* '''Panic snap:''' https://en.wikipedia.org/wiki/Panic_snap
 
* '''Panic snap:''' https://en.wikipedia.org/wiki/Panic_snap
 
* Snap shackle: https://en.wikipedia.org/wiki/Shackle
 
* Snap shackle: https://en.wikipedia.org/wiki/Shackle
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----
 
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Joints are useful for:
 
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* self centering
 
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* positive locking
 
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* connection by form closure
 
  
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=== Chains ===
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== Chains ==
  
 
* Sprockets: https://en.wikipedia.org/wiki/Sprocket
 
* Sprockets: https://en.wikipedia.org/wiki/Sprocket
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* Rigid chains: https://en.wikipedia.org/wiki/Rigid_chain_actuator
 
* Rigid chains: https://en.wikipedia.org/wiki/Rigid_chain_actuator
  
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=== For end-effectors and preceding ===
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== For end-effectors and preceding ==
  
 
* Chucks https://en.wikipedia.org/wiki/Chuck_(engineering)
 
* Chucks https://en.wikipedia.org/wiki/Chuck_(engineering)
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See [[ReChain frame systems]].
 
See [[ReChain frame systems]].
  
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== Likely useful for tensioning and other things ==
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=== Likely useful for tensioning and other things ===
+
  
 
* Turnbuckle: (but rather for length adjustment when load is displaced) https://en.wikipedia.org/wiki/Turnbuckle
 
* Turnbuckle: (but rather for length adjustment when load is displaced) https://en.wikipedia.org/wiki/Turnbuckle
 
* Differential screws: https://en.wikipedia.org/wiki/Differential_screw
 
* Differential screws: https://en.wikipedia.org/wiki/Differential_screw
 +
* excenter tensioners
 +
* knee-lever-tensioners (de: Kniehebelspanner) — <https://de.wikipedia.org/wiki/Kniehebel> — <https://de.wikipedia.org/wiki/Kniehebelpresse
 +
* mechanisms that act as intended breakage points but that are reversible ...
 
----
 
----
 
* Rolamite (but modified to gearbearings): https://en.m.wikipedia.org/wiki/Rolamite
 
* Rolamite (but modified to gearbearings): https://en.m.wikipedia.org/wiki/Rolamite
  
 +
== Positive displacement pumps ==
  
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=== Positive displacement pumps ===
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* PCP pumps: https://en.wikipedia.org/wiki/Progressing_cavity_pump <br> Good resources for modeling here: http://www2.mat.dtu.dk/people/J.Gravesen/MoineauPump/HypoEpi4_3.html <br> and here various configs: http://www2.mat.dtu.dk/people/J.Gravesen/MoineauPump/
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+
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* PCP pumps: https://en.wikipedia.org/wiki/Progressing_cavity_pump
+
 
* conventional piston pump: https://en.wikipedia.org/wiki/Piston_pump <br> but operated like described on page [[vacuum handling]]
 
* conventional piston pump: https://en.wikipedia.org/wiki/Piston_pump <br> but operated like described on page [[vacuum handling]]
 
* ( Roots blower: https://en.wikipedia.org/wiki/Roots-type_supercharger )
 
* ( Roots blower: https://en.wikipedia.org/wiki/Roots-type_supercharger )
  
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=== Probably too many small pins, too low stiffness, and better solutions present ===
+
== Misc ==
 +
 
 +
* "parts for nano-machines" collection on Thingiverse: <br>https://www.thingiverse.com/mechadense/collections/51015/things
 +
 
 +
== Probably too many small pins, too low stiffness, and better solutions present ==
  
 
* Sarrus linkage: https://en.wikipedia.org/wiki/Sarrus_linkage
 
* Sarrus linkage: https://en.wikipedia.org/wiki/Sarrus_linkage
 
* Paucellier linkage: https://en.wikipedia.org/wiki/Peaucellier%E2%80%93Lipkin_linkage
 
* Paucellier linkage: https://en.wikipedia.org/wiki/Peaucellier%E2%80%93Lipkin_linkage
 
* Schmidt coupling: https://en.wikipedia.org/wiki/Schmidt_coupling
 
* Schmidt coupling: https://en.wikipedia.org/wiki/Schmidt_coupling
 +
* Classical cycloidal drive: https://en.wikipedia.org/wiki/Cycloidal_drive <br> Very many bearings desirable here.
 +
'''Unsuitable CV type joints:'''
 +
* Rzeppa joint: https://en.wikipedia.org/wiki/Constant-velocity_joint#Rzeppa_joints <br> 2-DOF rolling balls not suitable for atomic scale due to atomic bumpiness.
 +
* Thompsonjoint: https://en.wikipedia.org/wiki/Constant-velocity_joint#Thompson_joints <br> Too intricate. Many small parts.
 +
 +
== Videos ==
 +
 +
'''GearDownForWhat''' has many awesome videos featuring <br>
 +
Ravigneaux gear-sets that need neither metal screws nor bearings. <br>
 +
See: https://www.youtube.com/@GearDownForWhat
 +
 +
'''RoTechnic'''
 +
* external: [https://youtu.be/qMDU5tlGUwU What are Eccentrically Cycloidal Gears? (youtube)]
 +
* internal: [https://youtu.be/xv5cd7Bg7Uk an easier robot arm actuator... (youtube)]
 +
These could be clanged to use both both epi- and hypo-cycloids on each gear. <br>
 +
See Hypo- & epi-cycloids 4:3 here: http://www2.mat.dtu.dk/people/J.Gravesen/MoineauPump/
 +
 +
'''Nicholas Seward'''
 +
* Some advantages of full profile cycloidal gearing [https://www.youtube.com/watch?v=Cu5LvIYXbU0&t=3s Cycloidal Modified Herringbone Rack & Pinion (youtube)]
 +
* Also the [[parallel SCARA]] mechanisms might be highly suitable for nanoscale robotics
 +
 +
= Related =
 +
 +
More generally: '''Principles that can help avoid the need for very many small screws:'''
 +
* Simplifying complexity of connection mechanisms by combining form closure and tension. <br>See: [[ReChain frame systems]]
 +
* Clamping housings with just one single big screw. <br>See: [[Tension redirection principle]]
 +
----
 +
Most generally: '''The design principles listed on page [[RepRec pick-and-place robots (GemGum)]].'''
 +
----
 +
* [[Machine element]]s, '''[[List of machine elements]]''' {{wikitodo|some overlap here; maybe merge pages}}
 +
* [[Component (gem-gum factory)]],[[Terminology for parts]]
 +
* [[Crystolecule]]
 +
* [[Superlubricity]], [[Friction in gem-gum technology]]

Latest revision as of 12:53, 22 May 2023

This page is basically just a list of mechanisms that
could be suitable and useful for future advanced diamondoid gemstone based nanosystems.

Related page: List of machine elements

What makes mechanisms "suitable"?

Unlike in macroscale machinery with machine parts at the lowermost possible size limit
there is no space for tiny screws that are much more tiny than the functional parts to clamp together.
(Functional parts is here referring to housings for gearboxes, essential machine element components, and such.)

Thus there is a need for designs that differ quite a bit from the conventional macroscale metal part engineering.
See the design principles listed on the page: RepRec pick-and-place robots (GemGum).

Under the lens of these constrains a particular set of
mechanisms/machine-elements emerges as especially promising.
This page features a collection of such mechanisms.

Macroscale side benefit

These mechanisms also allows for interesting 3D printable mechanics that
can cope without any metal screws whatsoever. A few big 3D printable screws suffice.

Whole classes of mechanisms

  • Rolling with static friction being absent and surfaces not being flat (atomic bumps) calls for gear-bearings.
    Peculiarly the periodic table of gearbearings
  • Enforced equipartitioned distribution of speed differences over several layers.
    See: Infinitesimal bearings

Related: Atomically precise bearings

External links

Bearings and Gearings

Couplings

  • https://en.wikipedia.org/wiki/Coupling#Oldham
  • Oldham coupling inspired gear coupling:
    Two linear-rack-gearbearings with each two rollers to define a plane. Those two sandwiched atop each other with
    their rolling direction arranged 90° to each other. Thus they have the same exact effect as an Oldham coupling. But with internal rolling rather than sliding.
  • (Schmidt coupling - this needs a lot of pins (ideally gear-bearings) thus listed in the likely unsuitable section further below)

CV type joints

Joints

For quick-release:

Chains

For end-effectors and preceding

Special screwdrivers end-effector mechanisms that:

  • put zero torque on the manipulated structure ("space screwdriver")
  • decouple tensioning from unloaded screwing structure ports (wiki-TODO: explain that principle more clearly with sketch)

These screwdrivers end-effector mechanisms shall operate on "tension-force hydrants".
See ReChain frame systems.

Likely useful for tensioning and other things

Positive displacement pumps

Misc

Probably too many small pins, too low stiffness, and better solutions present

Unsuitable CV type joints:

Videos

GearDownForWhat has many awesome videos featuring
Ravigneaux gear-sets that need neither metal screws nor bearings.
See: https://www.youtube.com/@GearDownForWhat

RoTechnic

These could be clanged to use both both epi- and hypo-cycloids on each gear.
See Hypo- & epi-cycloids 4:3 here: http://www2.mat.dtu.dk/people/J.Gravesen/MoineauPump/

Nicholas Seward

Related

More generally: Principles that can help avoid the need for very many small screws:

Most generally: The design principles listed on page RepRec pick-and-place robots (GemGum).

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