Magnetic torque-limiting device and method

• US 20070261868A1
• Filed: 08/31/2006
• Published: 11/15/2007
• Est. Priority Date: 05/12/2006
• Status: Abandoned Application

• Current Assignee: Pilling Weck Incorporated (Teleflex Incorporated)
• Original Assignee: Pilling Weck Incorporated (Teleflex Incorporated)
• Inventors: Gross, James R.
• Application Number:
  US11/513,052
• Publication Number:
  US 20070261868A1
• Time in Patent Office: Days
• US Class Current: 173/2
• CPC Class Codes: A61B 17/8875 Screwdrivers, spanners or wrenches
• CPC Class Codes: A61B 2090/031 torque limiting
• CPC Class Codes: B25B 23/142 specially adapted for hand operated wrenches or screwdrivers
• CPC Class Codes: B25B 23/1427 by mechanical means
• CPC Class Codes: F16D 7/00 Slip couplings, e.g. slipping on overload, for absorbing shock combined with yielding shaft couplings F16D3/14; fluid slip couplings F16D31/00 - F16D35/00

Abstract

In a torque-limiting device, a first end engages a fastener, a second end receives an applied torque, and a magnetic torque limiter transmits the applied torque from the second end to the first end to rotate the first end in conjunction with the second end when the applied torque is less than a predetermined limit.

Claims

1. A torque-limiting device comprising:

a first end to engage a fastener;

a second end to receive an applied torque; and

a magnetic torque limiter to transmit the applied torque from the second end to the first end to rotate the first end in conjunction with the second end when the applied torque is less than a predetermined limit.

2. The torque-limiting device according to claim 1, wherein the magnetic torque limiter further comprises a plurality of magnetically active materials juxtaposed in cooperative alignment.

3. The torque-limiting device according to claim 1, wherein the cooperative alignment of the plurality of magnetically active materials generates a magnetic circuit between the plurality of magnetically active materials.

4. A torque-limiting device comprising:

a shaft including a distal end to engage a fastener and a proximal end, the shaft defining an axis around which a clockwise rotation vector is aligned towards the distal end;

a housing pivotally secured to the proximal end, the housing including an outer surface and an inner surface, the inner surface including at least a first lug protruding radially inwardly into the housing and at least a second lug protruding radially inwardly into the housing;

a first magnet disposed within the housing, the first magnet being secured to the proximal end, the first magnet including a first bearing surface;

a second magnet juxtaposed in attractive cooperative alignment with the first magnet, the second magnet including a second bearing surface, wherein the first magnet is drawn towards the second magnet with an attractive magnetic force;

a first lever pivotally secured to the proximal end, the first lever having a first lever lug arm to bear against the first lug, the first lever having a first lever magnet arm to bear against the first bearing surface, wherein a clockwise external torque applied to the outer surface urges the first lug to bear against the first lever lug arm and urges the first lever to pivot clockwise, wherein the first lever magnet arm bears against the first bearing surface to urge the first magnet away from the second magnet in response to the clockwise urging of the first lever lug arm; and

a second lever pivotally secured to the proximal end, the second lever having a second lever lug arm to bear against the second lug, the second lever having a second lever magnet arm to bear against the second bearing surface, wherein the clockwise external torque applied to the outer surface urges the second lug to bear against the second lever lug arm and urges the second lever to pivot clockwise, wherein the second lever magnet arm bears against the second bearing surface to urge the second magnet away from the first magnet in response to the clockwise urging of the second lever lug arm and wherein rotation of the housing relative to the shaft is impeded until the first magnet and second magnet are separated by exceeding the attractive magnetic force between them.

5. The torque-limiting device according to claim 4, wherein the outer surface is configured to mate with an anatomically human hand.

6. A torque-limiting device comprising:

a shaft including a distal end to engage a fastener and a proximal end, the shaft defining an axis of rotation along which a rotation vector is aligned towards the distal end;

a housing pivotally secured to the proximal end, the housing including an outer surface and an inner surface, the inner surface including at least a first toothed region having teeth protruding radially inwardly into the housing and at least a second toothed region having teeth protruding radially inwardly into the housing;

a first magnet disposed within the housing, the first magnet being secured to the proximal end, the first magnet including a first toothed carrier;

a second magnet juxtaposed in attractive cooperative alignment with the first magnet, the second magnet including a second toothed carrier, wherein the first magnet is drawn towards the second magnet with an attractive magnetic force;

a first gear pivotally secured to the proximal end, the first gear having teeth to engage the first toothed region and the first toothed carrier, wherein a clockwise external torque applied to the outer surface urges the first toothed region to engage the first gear and clockwise rotate the first gear, wherein clockwise urging of the first gear urges the first magnet away from the second magnet; and

a second gear pivotally secured to the proximal end, the second gear having teeth to engage the second toothed region and the second toothed carrier, wherein the clockwise external torque applied to the outer surface urges the second toothed region to engage the second gear and clockwise rotate the second gear, wherein clockwise urging of the second gear urges the second magnet away from the first magnet and wherein rotation of the housing relative to the shaft is impeded until the first magnet and the second magnet are separated by exceeding the attractive magnetic force between them.

7. The torque-limiting device according to claim 6, wherein the cooperative alignment of the first and second magnets generates a magnetic circuit between the first and second magnets.

8. A torque-limiting device comprising:

a shaft including a distal end to engage a fastener and a proximal end;

a first magnetic assembly secured to the proximal end, the first magnetic assembly including a first plurality of magnets, each one of the first plurality of magnets having a North side adjacent to a South side of another one of the first plurality of magnets;

a housing pivotally secured to the proximal end, the housing including an outer surface to receive an applied torque; and

a second magnetic assembly secured to the housing, the second magnetic assembly including a second plurality of magnets, each one of the second plurality of magnets having a North side adjacent to a South side of another one of the second plurality of magnets, wherein each of the North and South sides of the second magnetic assembly is juxtaposed in attractive cooperative alignment with respective opposite South and North sides, respectively of, the first magnetic assembly to generate an array of attractive magnetic forces between the shaft and the housing.

9. The torque-limiting device according to claim 8, wherein rotation of the housing relative to the shaft is impeded until the applied torque exceeds a predetermined limit associated with the attractive magnetic force.

10. A torque-limiting device comprising:

a shaft including a distal end to engage a fastener and a proximal end, the shaft defining an axis of rotation along which a rotation vector is aligned towards the distal end;

a housing pivotally secured to the proximal end, the housing including an outer surface and an inner surface, the inner surface including at least a first toothed region having teeth protruding radially inwardly into the housing and at least a second toothed region having teeth protruding radially inwardly into the housing;

a first magnet disposed within the housing, the first magnet being secured to the proximal end, the first magnet including a first toothed carrier;

a second magnet juxtaposed in attractive cooperative alignment with the first magnet, the second magnet including a second toothed carrier, wherein the first magnet is aligned with the second magnet with an attractive magnetic force between them;

a first gear pivotally secured to the proximal end, the first gear having teeth to engage the first toothed region and the first toothed carrier, wherein a clockwise external torque applied to the outer surface urges the first toothed region to engage the first gear and clockwise rotate the first gear, wherein clockwise urging of the first gear urges the first magnet to laterally slide out of alignment with the second magnet; and

a second gear pivotally secured to the proximal end, the second gear having teeth to engage the second toothed region and the second toothed carrier, wherein the clockwise external torque applied to the outer surface urges the second toothed region to engage the second gear and clockwise rotate the second gear, wherein clockwise urging of the second gear urges the second magnet to laterally slide out of alignment with the first magnet and wherein rotation of the housing relative to the shaft is impeded until the first magnet and the second magnet laterally slide past each other by exceeding the attractive magnetic force between them.

11. The torque-limiting device according to claim 10, wherein the attractive magnetic force determines a maximum amount of torque that may be transmitted to the fastener from the housing.

12. A torque-limiting device comprising:

a shaft including a distal end to engage a fastener and a proximal end, the shaft defining an axis of rotation along which a rotation vector is aligned towards the distal end;

a housing pivotally secured to the proximal end, the housing including an outer surface and an inner surface, the inner surface including at least one lug protruding radially inwardly into the housing;

a first magnet disposed within the housing, the first magnet being secured to the proximal end;

a second magnet slidably secured to the proximal end and juxtaposed in attractive cooperative alignment with the first magnet, the second magnet including a magnet bearing surface, wherein the first magnet is urged towards alignment with the second magnet with an attractive magnetic force; and

a lever pivotally secured to the proximal end, the lever having a lug bearing surface to bear against the lug, the lever having an arm to bear against the magnet bearing surface, wherein a clockwise external torque applied to the outer surface urges the lug to bear against the lug bearing surface and urges the lever to pivot clockwise, wherein the arm bears against the magnet bearing surface and urges the second magnet out of alignment from the first magnet in response to the clockwise urging of the arm and wherein rotation of the housing relative to the shaft is impeded until the first magnet and the second magnet laterally slide past each other by exceeding the attractive magnetic force between them.

13. The torque-limiting device according to claim 12, wherein the attractive magnetic force determines a maximum amount of torque that may be transmitted to the fastener from the housing.

14. A torque-limiting device comprising:

a shaft including a distal end to engage a fastener and a proximal end;

a first magnetic assembly secured to the proximal end, the first magnetic assembly including a first plurality of magnets;

a housing pivotally secured to the proximal end, the housing including an outer surface to receive an applied torque and the housing including an inner surface, the inner surface including at least one lug protruding radially inwardly into the housing; and

a second magnetic assembly pivotally secured to the proximal end, the second magnetic assembly including a second plurality of magnets, an axis about which the second magnetic assembly rotates, and a lip offset from the axis, wherein the second magnetic assembly is juxtaposed in attractive cooperative alignment with the first magnetic assembly to generate an attractive magnetic force between them, wherein rotation of the housing relative to the shaft urges the lug to bear upon the lip and rotate the second magnetic assembly away from and out of alignment with the first magnetic assembly, wherein rotation of the housing relative to the shaft is impeded until the separation of the first magnetic assembly and the second magnetic assembly in response to exceeding the attractive magnetic force between them.

15. The torque-limiting device according to claim 14, wherein the attractive magnetic force determines a maximum amount of torque that may be transmitted to the fastener from the housing.

16. A torque-limiting device comprising:

a shaft including a distal end to engage a fastener and a proximal end, the shaft defining an axis of rotation along which a rotation vector is aligned towards the distal end;

a housing pivotally secured to the proximal end, the housing including an outer surface and an inner surface, the inner surface including at least one lug protruding radially inwardly into the housing;

a race secured to the proximal end, the race being oriented perpendicularly relative to the shaft;

a first magnet slidably disposed within the race, the first magnet including a bearing surface to bear against the lug; and

a second magnet slidably disposed within the race and juxtaposed in repulsive cooperative alignment with the first magnet, wherein the first magnet is repulsed from the second magnet with a repulsive magnetic force that urges the bearing surface against the lug to impede rotation of the housing relative to the shaft, wherein an applied torque to the outer surface urges the lug to bear against the bearing surface and urges the first magnet towards the second magnet and wherein rotation of the housing relative to the shaft is impeded until the applied torque exceeds a predetermined limit.

17. The torque-limiting device according to claim 16, further comprising:

a second lug protruding radially inwardly into the housing;

a second bearing surface to bear against the second lug and urge the second magnet towards the first magnet in response to the applied torque.

18. A torque-limiting device comprising:

shaft means for engaging a fastener;

handle means for receiving an applied torque; and

a magnetic torque-limiting means coupling the shaft means and handle means and magnetically limiting an amount of torque externally applied to the handle means from being transmitted to the fastener, the magnetic torque-limiting means being configured to transmit the applied torque from the handle means to the shaft means in response to the applied torque being less than a predetermined torque limit.

19. The torque-limiting device according to claim 18, wherein the magnetic torque-limiting means is configured to allow the shaft means to rotate relative to the handle means in response to the applied torque being greater than the predetermined torque limit.

20. A torque meter comprising:

a cam to receive an applied torque; and

a magnetic coupling, the magnetic coupling including a pair of magnetically active components that are urged together by an attractive magnetic force, wherein the cam is configured to urge the pair of magnetically active components apart in response to the applied torque.

21. The torque meter according to claim 20, further comprising:

an indicator to indicate the applied torque in response to rotation of the cam relative to the magnetic coupling.