Gauntlet Tensioner with 2-Way Ratchet

The 2-Way ratchet Tensioner allows a user to move a tensioner along a linear track in either direction by pulling or pushing on a handle with one finger, yet the tensioner is latched in position (and will not move along the track) unless the handle is pushed or pulled.

Maker/DIY

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Description

Warning: This device has not been printed nor tested and it may not perform as described. It is provided here at this time for others to share in the research and development. It should not be considered ready for the average e-NABLE volunteer to fabricate for a recipient.

The The Whippletree tensioner https://www.youmagine.com/designs/adaptive-grip-mechanism-for-prosthetic-hand  has evolved to using pegs as pulleys and thus eliminates most of the knot-tying associated with assembling the e-NABLE hands.   It also provides an improved adaptive grip in which the fingers each move appropriately to grip oddly shaped objects. When the whippletree is used without this ratchet mechanism, the degree to which the fingers are flexed when the wrist is in it’s neutral (straight) position will be determined by the length of the tendons, and some adjustment may be needed in the system. The 2-way Ratchet Tensioner provides a means for the user to easily make this adjustment anytime during use.

For instance, a user can place the Raptor Reloaded Hand (with this specially equipped gauntlet) on a bicycle handlebar with the wrist in a comfortable position, then pull back on the tensioner handle until the fingers tighten around the handlebar. With this adjusted starting position, flexion or extension of the wrist causes further flexion or extension of the fingers in the normal way.

This device also addresses a design concern where 3-jointed digits (like the human hand) require more displacement of the tendon cords (more flexion of the wrist in a wrist-actuated device) than do the 2-jointed digits on the regular Raptor, Raptor Reloaded and Cyborg Beast hands provided by e-NABLE. It is expected that the 2-Way Ratchet Tensioner will enable more people to comfortably use 3-jointed fingers like the Flexy-Hand and Falcon Hand.  

Small o-rings pull the ratchet pawl toward the ratchet surface.  It will be necessary to cut away a bit of material to fit the o-rings onto the bracket. (An overhang could have been a problem if it were printed open there.)

I'm working in tinkercad and it is an untested work in progress.  I just made it public.  

https://www.tinkercad.com/things/eDQnWC4OI9M-2-way-ratchet-tensioner  

All are welcome to duplicate and build on the design but give attribution to Raptor Reloaded by e-NABLE https://www.youmagine.com/designs/raptor-reloaded-by-e-nable for the hand and gauntlet design.  Please provide feedback on what you learn.

Prior Art:

Raptor Reloaded Hand  https://www.youmagine.com/designs/the-raptor-hand-by-e-nable#!design-documents 

Whippletree  http://www.thingiverse.com/thing:392970  and https://www.youmagine.com/designs/adaptive-grip-mechanism-for-prosthetic-hand 

Simplified Movement Printer Sheet Stack Edge Guide US Patent No.: 7,527,259 B2 https://www.google.com/patents/US7527259?dq=7527259B2&hl=en&sa=X&ei=osTXVK-JC4GyggSvloLYCg&ved=0CB0Q6AEwAA  

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Comments

Ac80d506490a3b166fc42c21cab7dda9?default=blank&size=40joma added this to the Linus collection ago
Cfc7c6e7b496558ac6d32ea100afd784?default=blank&size=40Andi_ts added this to the things to print collection ago
522a863b565c40259cc81416f4a20efe?default=blank&size=40Thomas Bauer added this to the Arms collection ago
A3c378306573f417c0867e16c16f0992?default=blank&size=40Marcelo Carvalho added this to the Medical collection ago
Mini sheepJonathan Bischof printed this ago
Carousel thumb holding the o ring
Printed on:
ultimaker original
Result:
not printed
Feedback:
Suggestion for holding the O-ring: T-slot (See comments section)
Mini avitarSkip Meetze published this design ago