Finger Mechanism for a natural, powerful prosthetic hand
Precision Assemblies and Components

782436:001.26

Natural and powerful like the human hand

This precision assembly is specifically designed to provide a comfortable, intuitive and precise prosthetic hand that provides amputees with exceptionally powerful and natural grip. This means that tying shoes like a natural opening of doors is finally possible again.

This high-precision finger mechanism offers you significant advantages:

1.	Precise, proportional control of the hand with 2 µm for coordinated and natural movement
2.	Maximum control of your own movements, as the torque of the motor is converted 100% into force
3.	Extreme durability and protection against overloading due to the robust design with steel

Regaining of control and confidence

A leading manufacturer of prostheses contacted us with the task of manufacturing a mechanism that would be used in an artificial hand. In close cooperation with the customer, we developed a ball screw drive integrated in the support structure. Due to miniaturization, the threaded drive as well as the associated pressure bearing had to be adapted. The recirculating ball nut is designed as a thrust piece, which avoids additional parts with narrow tolerances for functional integration. The pressure bearing for absorbing the considerable axial forces was manufactured with a reinforced outer ring to allow installation without a completely enclosing support structure. All parts are made of stainless steel. This is the only way to withstand the peak forces incurred in using a hand.

The drive is coupled in via a beveled wheel, which is not shown here. Series production is supported by devices for assembly and a run-in stand. The first 1000 full strokes are executed on the run-in stand in order to ensure very even running behavior even with a rearward-acting force (finger is moved by external forces). After the run-in, the unit is cleaned again and provided with a lifetime lubrication.

Further applications

Prosthetics, bionics, sensor technology, research projects

Specifications

782436:001.26		X
Travel	[mm; deg]	5
Repeatability unidirectional	[µm; deg]	± 2
Repeatability bidirectional	[µm; deg]	± 3
Max. Speed	[mm/s]	3
Motor		DC-Motor
Drive		Ball Screw
Feedback		Open Loop