Patent ID: 11971020
Assignee: DEUTSCHES ZENTRUM FÜR LUFT-UND RAUMFAHRT E.V.
Field: Engines, pumps, turbines (Mechanical engineering)
Classification: CPC F | IPC F

Claim 15:
16. An apparatus for clamping and releasing a bolt, comprising
a clamping sleeve configured for receiving a part of the bolt,
a main body enclosing a receptacle with a depth direction and a free cross sectional area decreasing in depth direction, the receptacle being configured for receiving a part of the clamping sleeve,
a counter-bearing supported against the main body, and
an actuator arranged between the clamping sleeve and the counter-bearing,
wherein the actuator comprises
a virtual actuator main axis,
two endpieces,
a compression spring, the compression spring elastically supporting the two endpieces against one another in the direction of the actuator main axis, and
a wire that is made of a shape-memory alloy and can be controlled to implement a change in length,
wherein the wire comprises at least six contiguous length portions, each of the contiguous length portions extending and being tensioned between the two endpieces along the actuator main axis, and
wherein the length portions are
arranged with regard to one another in at least an axially symmetric way and a rotationally symmetric way with respect to the actuator main axis, and
oriented at equally sized angles with respect to a virtual reference plane to which the actuator main axis is a surface normal according to claim 1, and

wherein the actuator is arranged between the clamping sleeve and the counter-bearing in such a way that the compression spring presses the clamping sleeve into the receptacle in the main body.