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US 8,770,981 B2Granted
Actuation mechanism for braille displays
AssigneeBoard of Trustees of Northern Illinois University
InventorsDavid Schroeder, Graham Bogda, Brendan Vishoot
Life of this patent
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Abstract
According to the present invention, there is provided an improved refreshable tactile display apparatus including a housing, bias compression springs, sliding blocks, pins, and a shape memory alloy wire. The sliding block is actuated by the interaction between the bias compression spring and the shape memory alloy wire. The shape memory alloy wire is then activated by current driven from a power supply in either a modulated or unmodulated fashion.
Claims20
A refreshable tactile display pin comprising:
- a pin that can be raised and lowered, and
- a sliding block slidable to contact said pin and raise said pin, and to retract from contact with said pin and render lowerable said pin, said sliding block connected to a single bias compression spring for biasing said sliding block into contact with said pin, said sliding block being additionally connected to a single wire having shape memory properties that upon activation shortens in length in opposition to said bias compression spring, for causing said sliding block to retract from contact with said pin;
- wherein the single compression spring and single wire extend from only a first side of the sliding block.
A refreshable tactile display pin comprising:
- a pin that can be raised and lowered, and
- a sliding block slidable to contact said pin and raise said pin, and to retract from contact with said pin and render lowerable said pin, wherein the sliding block comprises:
- a first end;
- a bias compression spring connected to only the first end of the sliding block for biasing the sliding block into contact with the pin;
- a wire having shape memory properties connected to only the first end of the sliding block;
- and
- a second end opposite the first end;
- wherein the wire moves the second end of the sliding block into and out of contact with the pin.
5 more elements
Dependencies are inferred from the claim text.