Method and apparatus for spin sensing in munitions

• US 20070181028A1
• Filed: 11/22/2004
• Published: 08/09/2007
• Est. Priority Date: 11/22/2004
• Status: Active Grant

• Current Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Original Assignee: Alliant Techsystems Incorporated (Northrop Grumman Corporation)
• Inventors: Schmidt, Robert, Tomes, Mark
• Granted Patent: US 8,113,118 B2
• Time in Patent Office: Days
• US Class Current: 102/238
• CPC Class Codes: F42C 15/26 using centrifugal force
• CPC Class Codes: F42C 15/40 wherein the safety or arming action is effected electrically

Abstract

A spin sensor and method of detecting fuze spin are disclosed. The spin sensor, including a fuze housing, a sense weight and a rotating induction device. The rotating induction device comprises a first rotatable element affixed to the fuze housing and a second rotatable element affixed to the sense weight. The second rotatable element is mechanically coupled to the first rotatable element such that it may rotate relative to the first rotatable element. In addition, the second rotatable element is inductively coupled to the first rotatable element such that the relative rotation between the first rotatable element and the second rotatable element generates a spin signal on an electrical connection to the rotating induction device. The spin signal may be compared to a suitable spin profile to determine if a valid spin environment is present.

Claims

1. A spin sensor, comprising:

a fuze housing;

a sense weight; and

a rotating induction device comprising;

a first element affixed to the fuze housing;

a second element affixed to the sense weight, the second element rotationally coupled and inductively coupled to the first element; and

an electrical connection configured for generating a spin signal correlated with a relative rotation between the first element and the second element.

2. The spin sensor of claim 1, further comprising at least one analyzer operably coupled to the spin signal, the at least one analyzer configured for sampling the spin signal to develop an actual spin profile and comparing the actual spin profile to an acceptable spin profile.

3. The spin sensor of claim 2, wherein the acceptable spin profile and the actual spin profile incorporate at least one spin parameter selected from the group consisting of revolution count, spin rate, increase in spin rate and spin signal amplitude.

4. The spin sensor of claim 2, wherein the at least one analyzer comprises at least one programmable controller.

5. The spin sensor of claim 1, further comprising:

a spin signal conditioner operably coupled to the spin signal and configured for generating a conditioned spin signal; and

at least one analyzer operably coupled to the conditioned spin signal, the at least one analyzer configured for sampling the conditioned spin signal to develop an actual spin profile and comparing the actual spin profile to an acceptable spin profile.

6. The spin sensor of claim 5, wherein the acceptable spin profile and the actual spin profile incorporate at least one spin parameter selected from the group consisting of revolution count, spin rate, increase in spin rate and spin signal amplitude.

7. The spin sensor of claim 5, wherein the at least one analyzer comprises at least one programmable controller.

8. The spin sensor of claim 5, wherein the spin signal conditioner is configured to generate the conditioned spin signal by modifying the spin signal, the modification including at least one function selected from the group consisting of filtering, amplifying, attenuating, and digitizing.

9. The spin sensor of claim 1, wherein a magnetic detent attribute of the rotating induction device maintains the relative rotation at substantially near zero until a relative angular acceleration threshold between the first element and the second element is exceeded.

10. The spin sensor of claim 1, wherein the relative rotation is related to a mass of the sense weight, the mass providing an angular inertial force impeding angular acceleration of the second element relative to the first element.

11. The spin sensor of claim 1, wherein the first element is a stator of the rotating induction device and the second element is a rotor of the rotating induction device.

12. The spin sensor of claim 11, wherein the stator comprises a wire coil and the rotor comprises a permanent magnet.

13. The spin sensor of claim 11, wherein the stator comprises a permanent magnet and the rotor comprises a wire coil.

14. The spin sensor of claim 1, wherein the first element is a rotor of the rotating induction device and the second element is a stator of the rotating induction device.

15. The spin sensor of claim 14, wherein the stator comprises a wire coil and the rotor comprises a permanent magnet.

16. The spin sensor of claim 14, wherein the stator comprises a permanent magnet and the rotor comprises a wire coil.

17. An explosive projectile, comprising:

an encasement;

an explosive material disposed within the encasement and configured for detonation; and

a fuze disposed within the encasement, comprising;

a fuze housing;

a sense weight; and

a rotating induction device comprising;

a first element affixed to the fuze housing;

a second element affixed to the sense weight, the second element rotationally coupled and inductively coupled to the first element; and

an electrical connection configured for generating a spin signal correlated with a relative rotation between the first element and the second element.

18. A method of sensing fuze spin, comprising:

providing a sense weight rotationally coupled to a fuze housing;

rotating the fuze housing;

detecting a relative rotation between the sense weight and the fuze housing;

converting the detected relative rotation to a spin signal;

sampling the spin signal to develop an actual spin profile of the fuze housing; and

comparing the actual spin profile to an acceptable spin profile.

19. The method of claim 18, further comprising selecting the acceptable spin profile and the actual spin profile to incorporate at least one spin parameter selected from the group consisting of revolution count, spin rate, increase in spin rate and spin signal amplitude.

20. The method of claim 18, further comprising maintaining the relative rotation at substantially near zero until a relative angular acceleration threshold between the sense weight and the fuze housing exceeds a magnetic detent attribute between the sense weight and the fuze housing.

21. The method of claim 18, further comprising modifying the relative rotation by adjusting a mass of the sense weight to modify an angular inertial force impeding angular acceleration of the sense weight.

22. The method of claim 18, further comprising conditioning the spin signal prior to sampling the spin signal.

23. The method of claim 22, wherein the conditioning comprises at least one function selected from the group consisting of filtering, amplifying, attenuating, and digitizing.

24. A method of sensing fuze spin, comprising:

inductively coupling a first element affixed to a fuze housing and a second element affixed to a sense weight;

generating a spin signal correlated to a relative rotation of the first element relative to the second element;

sampling the spin signal to develop an actual spin profile of the fuze housing; and

comparing the actual spin profile to an acceptable spin profile.

25. The method of claim 24, further comprising selecting the acceptable spin profile and the actual spin profile to incorporate at least one spin parameter selected from the group consisting of revolution count, spin rate, increase in spin rate and spin signal amplitude.

26. The method of claim 24, further comprising maintaining the relative rotation at substantially near zero until a relative angular acceleration threshold between the sense weight and the fuze housing exceeds a magnetic detent attribute between the sense weight and the fuze housing.

27. The method of claim 24, further comprising modifying the relative rotation by adjusting a mass of the sense weight to modify an angular inertial force impeding angular acceleration of the sense weight.

28. The method of claim 24, further comprising conditioning the spin signal prior to sampling the spin signal.

29. The method of claim 28, wherein the conditioning comprises at least one function selected from the group consisting of filtering, amplifying, attenuating, and digitizing.