According to the present invention a gripping device comprises: a lower finger-section pivoted at its lower end to a base and at
least a first upper finger-section pivoted to the lower section, a driving means mounted on said base, and a linkage between
said driving means and said finger-sections for preferentially rotatings aid lower section about its pivot, said linkage being
arranged so that,. upon rotation of said lower section being stopped or strongly resisted by an object to be gripped, the
drive transfers to said first upper section causing it to rotate about its pivot towards the lower section and thereby tend to
grip the object between said finger-sections.
The linkage may comprise an equalizer bar having an intermediate point linearly moveable by said driving means and
having a first rod linking one end of the bar to the lower finger-section and a second rod Sinking the other end of the bar to
a crank pivoted on said base, said crank being linked to the first upper finger section bya third rod, the linkage geometry,
primarily, being such that the mechanical advantage obtained via the first rod where by to cause said initial preferential rotation
of the lower finger section.
In a form closely simulating the action of a human finger there is provided a second upper finger-section pivoted to said first
upper finger-section and a linkage between said first and second upper finger-sections whereby rotation of said first about
its pivot causes rotation of said second about its pivot.
A robotic hand may comprise four devices as defined in the immediately preceding paragraph pivoted to a common base
and simulating the action of the four human fingers. In one form of hand the index finger comprises a gripping device as
aforesaid operable via one said linkage by one said driving means and the three fingers coupled together to be operable
simultaneously, but independently of the index finger, via a second said linkage by a second said driving means.
The driving means maybe a rotary electric motor or motors.
The above extract is taken from a patent for a manipulator (shown in the accompanying drawing below) and has been written by a patent agent. It describes the action of the gripper and is merely the introduction. The actual patent is of course written to prevent possible infringements and is even more explicit and consequently far less intelligible. Clearly it is a lot easier to communicate using drawings.
Mechanical Engineering Design Topics Page
Pages created by David Price - 9/08/95
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