Gearless torque drive

Patent metadata

Field	Value
Publication number	US-10920833-B2
Application number	US-201815946284-A
Country	US
Kind code	B2
Filing date	Apr 5, 2018
Priority date	Oct 7, 2015
Publication date	Feb 16, 2021
Grant date	Feb 16, 2021

Abstract

Torque-limiting mechanisms comprising an upper shank component with a torque-limiting interface, a lower shank component with a torque-limiting interface, and a biasing element. Torque-limiting interfaces having a plurality of undulations arranged around an axial bore or drive socket and separated by a plurality of transition regions, with each undulation having an upslope, a peak, and a downslope. The torque-limiting interfaces are configured to engage and disengage to provide torque transmission with predetermined torque limits at various rotational speeds and for amounts of actuations while remaining within a specified operational range.

First claim

The invention claimed is:

1. A torque-limiting mechanism comprising:
an upper shank component comprising a proximal end, a distal end, an axial bore connecting the proximal end and the distal end, and a first undulated torque-limiting interface disposed on the proximal end;
a lower shank component comprising a proximal end, a distal end, a drive socket disposed between the proximal end and the distal end, and a second undulated torque-limiting interface disposed on the proximal end, wherein the upper shank component and the lower shank component are aligned along an axis in the direction of the axial bore and the drive socket with the first torque-limiting interface in contact with the second torque-limiting interface; and
a compressible biasing element with a 50 to 100 durometer rating configured to apply compressive force (F) along the axis to compress the first torque-limiting interface against the second torque-limiting interface;
wherein the upper shank component and the lower shank component are configured to engage to rotate together when torque is applied to the lower shank component via the drive socket; and,
wherein the upper shank component and the lower shank component are configured to disengage when a predetermined torque limit is exceeded,
the first torque-limiting interface comprises a first plurality of non-metallic undulations arranged around the axial bore and separated by a first plurality of transition regions;
the second torque-limiting interface comprises a second plurality of non-metallic undulations arranged around the drive socket and separated by a second plurality of transition regions; and
each undulation comprises an upslope, a peak, and a downslope, wherein each downslope has a declination angle of between 5 and 30 degrees such that degradation is mitigated between the first and second pluralities of undulations.

2. The torque-limiting mechanism of claim 1 , wherein: the first and second pluralities are equal in number.

3. The torque-limiting mechanism of claim 1 , wherein: each upslope has an inclination angle between 3 degrees and 15 degrees.

4. The torque-limiting mechanism of claim 1 , wherein: each upslope has an inclination angle between 5 degrees and 9 degrees.

5. The torque-limiting mechanism of claim 1 , wherein: each upslope has an inclination angle between 6 degrees and 8 degrees.

6. The torque-limiting mechanism of claim 1 , wherein: each upslope has an inclination angle of 7 degrees.

7. The torque-limiting mechanism of claim 1 , wherein the predetermined torque limit is between 0.1 Newton-meter and 3.0 Newton-meter.

8. The torque-limiting mechanism of claim 1 , wherein the predetermined torque limit is between 3.0 Newton-meter and 6.0 Newton-meter.

9. The torque-limiting mechanism of claim 2 wherein the first torque-limiting interface and second torque-limiting interface each comprise three undulations.

10. The torque-limiting mechanism of claim 2 wherein the first torque-limiting interface and second torque-limiting interface each comprise four undulations.

11. The torque-limiting mechanism of claim 2 wherein the first torque-limiting interface and second torque-limiting interface each comprise five undulations.

12. The torque-limiting mechanism of claim 1 wherein the torque-limiting mechanism provides a predetermined torque between 0.1 Newton-meter and 6 Newton-meters of torque at a rotational speed between 50 RPM and 1300 RPM over at least one of 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 105, 110, 120, 150, 180, 200, 220, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, 1000, 1050, 1100, 1150, 1200, 1250, 1300, 1350, 1400, 1450, 1500, 1550, 1600, 1650, 1700, 1750, 1800, 1850, 1900, 1950, 2000, 2100, 2200, 2300, 2400, or 2500 actuations while remaining within a specified operational range.

13. The torque-limiting mechanism of claim 1 , wherein each downslope has a declination angle of between 10 and 30 degrees.

14. The torque-limiting mechanism of claim 13 , wherein each downslope has a declination angle of between 10 and 20 degrees.

15. The torque-limiting mechanism of claim 14 , wherein each downslope has a declination angle of 15 degrees.

16. The torque-limiting mechanism of claim 1 , wherein each upslope has a functional path length defined along a midpoint of each undulation, each downslope has a functional path length defined along the midpoint of each undulation, and the ratio of the functional path length of the upslope to the functional path length of the downslope is between 2.2:1 and 1.8:1.

17. The torque-limiting mechanism of claim 1 , wherein the lower shank component includes a retaining cavity configured to receive the compressible biasing elements, such that the compressible biasing element is retained within the retaining cavity when the compressible biasing element is compressed to expand radially.

18. The torque-limiting mechanism of claim 2 , wherein each peak has a length between an adjacent upslope ad an adjacent downslope, each transition region has a length between an adjacent upslope and an adjacent downslope, and the length of the peak is equal to the length of the transition region.

19. The torque-limiting mechanism of claim 1 , wherein the ratio of the first plurality of undulations arranged around the axial bore to the first plurality of transition regions is at least 65:35, and
wherein the ratio of second plurality of undulations arranged around the drive socket to the second plurality of transition regions is at least 65:35.

20. The torque-limiting mechanism of claim 1 , further comprising an actuation indicating system configured to create an audible indication when the upper shank component and the lower shank component have slipped past each other.

Assignees

• Eca Medical Instr

Inventors

• Nino John
• Ivinson David
• Tory David

Classifications

• B25B23/145

  specially adapted for fluid operated wrenches or screwdrivers · CPC title

• A61B17/8875

  Screwdrivers, spanners or wrenches · CPC title

• A61B17/16

  Instruments for performing osteoclasis; Drills or chisels for bones; Trepans {(arthroscopic bone cutters A61B17/320016)} · CPC title

• B25B23/141

  Mechanical overload release couplings · CPC title

• F16D7/044 Primary

  the axially moving part being coaxial with the rotation, e.g. a gear with face teeth · CPC title