S-shaped coupling spring for middle ear implants
A loading spring has an inner end that engages the outer end of a middle ear transducer, an outer end that engages a fixed anatomical structure within the middle ear of the recipient patient, and a center of mass located on a common line between the inner end and the outer end. The loading spring also has an s-shape with a central spring axis along the common line. And the loading spring is configured for displacement of the inner end and the outer end along the central spring axis to fit the loading spring between the transducer and the fixed anatomical structure with a loading force that is within a defined range and entirely along a center axis of the middle ear transducer and the central spring axis.
1. A middle ear implant arrangement comprising:
an implantable electromechanical transducer with an inner end and an outer end connected by a center transducer axis, configured to convert an input electrical stimulation signal into a corresponding output mechanical stimulation signal;
a cochlear engagement member located at the inner end of the transducer with a cochlear engagement surface configured to couple the mechanical stimulation signal to an outer cochlear surface of a recipient patient; and
a loading spring having:
i. an inner end that engages the outer end of the transducer,
ii. an outer end configured to engage a fixed anatomical structure within a middle ear of the recipient patient; and
iii. a center of mass located on a common line between the inner end and the outer end of the loading spring;
wherein the loading spring has an s-shape with a central spring axis along the common line, and
wherein the loading spring is configured for displacement of the inner end and the outer end of the loading spring along the central spring axis so as to fit the loading spring between the transducer and the fixed anatomical structure with a loading force that is within a defined range and entirely along the center transducer axis and the central spring axis.
2. The middle ear implant arrangement according to claim 1 , wherein the loading spring has an s-shape lying in a two-dimensional plane.
3. The middle ear implant arrangement according to claim 1 , wherein the loading spring is point symmetric about the center of mass.
4. The middle ear implant arrangement according to claim 1 , wherein the loading spring is configured for displacement of the inner end and the outer end of the loading spring of up to 200 μm with a loading force that is within the defined range.
5. The middle ear implant arrangement according to claim 1 , wherein the loading force is up to 100 mN.
6. The middle ear implant arrangement according to claim 1 , wherein the defined range is 10-20 mN.
7. The middle ear implant arrangement according to claim 1 , wherein the loading spring is made of Nitinol or titanium.
8. The middle ear implant arrangement according to claim 1 , wherein the loading spring comprises of a plurality of spring sections having equal absolute values of curvatures.
9. A loading spring for a middle ear implant comprising:
an inner end configured to engage an outer end of a middle ear transducer,
an outer end configured to engage a fixed anatomical structure within a middle ear of a recipient patient; and
a center of mass located on a common line between the inner end and the outer end of the loading spring;
wherein the loading spring has an s-shape with a central spring axis along the common line, and
wherein the loading spring is configured for displacement of the inner end and the outer end of the loading spring along the central spring axis so as to fit the loading spring between the transducer and the fixed anatomical structure with a loading force that is within a defined range and entirely along a center axis of the middle ear transducer and the central spring axis.
10. The loading spring according to claim 9 , wherein the loading spring has an s-shape lying in a two-dimensional plane.
11. The loading spring according to claim 9 , wherein the loading spring is point symmetric about the center of mass.
12. The loading spring according to claim 9 , wherein the loading spring is configured for displacement of the inner end and the outer end of the loading spring of up to 200 μm with a loading force that is within the defined range.
13. The loading spring according to claim 9 , wherein the loading force is up to 100 mN.
14. The loading spring according to claim 9 , wherein the defined range is 10-20 mN.
15. The loading spring according to claim 9 , wherein the loading spring is made of Nitinol or titanium.
16. The loading spring according to claim 9 , wherein the loading spring comprises of a plurality of spring sections having equal absolute values of curvatures.