Microelectromechanical systems (MEMS)-type high-capacity inertial-switching device

• US 6,314,887 B1
• Filed: 04/24/2000
• Issued: 11/13/2001
• Est. Priority Date: 02/22/2000
• Status: Expired due to Fees

• Current Assignee: The United States Of America As Represented By The Secretary Of The Army
• Original Assignee: The United States Of America As Represented By The Secretary Of The Army
• Inventors: Robinson, Charles H.
• Primary Examiner(s): Jordan, Charles T.
• Assistant Examiner(s): Lofdahl, Jordan M
• Application Number:
  US09/556,989
• Time in Patent Office: 568 Days
• Field of Search: 102/222, 102/247, 102/262, 102/235
• US Class Current: 102/262
• CPC Class Codes: F42C 19/06 Electric contact parts specially adapted for use with electric fuzes switches operated by change of speed H01H35/06; switches operated by change of acceleration, e.g. shock or vibration, inertia switches H01H35/14; fluid-pressure-operated switches H01H35/24
• CPC Class Codes: H01H 1/0036 Switches making use of microelectromechanical systems [MEMS] for electromagnetic relays H01H50/005; for electrostatic relays H01H59/0009
• CPC Class Codes: H01H 2001/0047 operable only by mechanical latching
• CPC Class Codes: H01H 35/14 Switches operated by change of acceleration, e.g. by shock or vibration, inertia switch wherein the liquid constitutes a contact of the switch H01H29/002

Abstract

Various ultra-miniature, monolithic inertial switching (G-switch) devices used in safety and arming (S&A) devices for projected munitions, which operate in accordance with a shuttle member (50), which effectuates current switching of around an ampere of current when subjected to a threshold inertial loading (for example, an impact or gun launch of a projection munition). The embodiments of the invention can be a passive threshold G-switch with or without switch enable and arming capability. The embodiments (100, 200) of the invention use either mechanical or electromechanical switch enable functioning and can optionally include a shuttle time-delay feature (54). Both embodiments can incorporate various designs for a switching assembly (75) such as latching single-throw switch having the configurations of either a normally-open, double pole, single-throw switch or a normally-open, single pole, single-throw switch, wherein switch closing occurs when the shuttle member (50) experiences inertial loading and penetrates the switching assembly (75).

Claims

1. A microelectromechanical systems (MEMS) type switching device, the device comprising:

a base;

a sliding shuttle member slidably mounted on the base;

an anchor assembly having at least one flexible anchor leg attached to the shuttle member wherein the at least one anchor leg cooperatively and slidably engages a constriction member through at least one movable anchor foot attached to a distal end of each anchor leg, the constriction is attached to the base; and

an electrical switching assembly attached to the base wherein the shuttle member has a head member that actuates the switching assembly when the switching device is subjected to inertial loading.

2. The device as recited in 1, wherein the anchor assembly consist essentially of the at least one flexible anchor leg attached to the shuttle member wherein the at least one anchor leg cooperatively and slidably engages a constriction member through the at least one movable anchor foot attached to a distal end of each anchor leg, the constriction is attached to the base, thereby providing a threshold gravitational (G)-switch.

3. The device as recited in 1, wherein the anchor assembly further includes a means for enabling the switching-device and there are two anchor legs and two anchor feet.

4. The device as recited in 3, wherein the means for enabling the switching device comprises:

an electromechanical actuator and a movable linchpin, wherein the electromechanical actuator attaches to at least two electrical bonding pads, a first end of the linchpin member slidably moves within the electromechanical actuator and the other end of the linchpin slidably moves between the anchor feet,

whereby when the means for enabling the switching device is actuated, the linchpin slides out from between the anchor feet, thereby allowing the anchor feet to move towards each other and allowing the shuttle member to slide when the switching device is subjected to inertial loading.

5. The device as recited in 3, wherein the means for enabling the switching device comprises a mechanical lift arm assembly that attaches to a support member for a lift arm, the lift arm attaches to a the linchpin when the support member is moved by an external actuator means, the other end of the linchpin slidably moves between the anchor feet,

whereby when the lift arm assembly is actuated, the linchpin slides out from between the anchor feet, thereby allowing the anchor feet to move towards each other and allowing the shuttle member to slide when the switching device is subjected to inertial loading.

6. The device as recited in 1, wherein the sliding shuttle member is juxtaposed to a zig-zag track on each side of the shuttle member, in which the shuttle member slides, the shuttle member has teeth members on each side of the shuttle member that cooperatively slidably engage the zig-zag track members, thereby enabling time-delay for travel of the shuttle member when subjected to inertial loading.

7. The device as recited in 1, wherein the electrical switching assembly comprises:

at least one pair of movable contact hammer members that are attached to the base, the hammer members cooperatively engage the shuttle'"'"'s head member during actuation of the switching assembly; and

at least one pair of electrical bonding pads that are attached to the base and are for external electrical connection to the switching device.

8. The device as recited in 7, wherein the at least one pair of electrical bonding pads are electrically connected to the at least one pair of contact hammer members, wherein each hammer member has an electrically conductive surface coating material, and the shuttle'"'"'s head member has an electrically conductive surface coating material,

whereby the head member causes switching action during contact by the at least one pair of hammer members.

9. The device as recited in 7, wherein the electrical switching assembly further includes at least two pairs of electrically conductive contact anvils that are flexibly attached to the base and electrically isolated from each other, each anvil member is electrically attached to a bonding pad member that is attached to the base, and each pair of the anvils are juxtaposed to one of the contact hammer members,

whereby when the head member causes switching action by engaging the at least one pair of hammer members with each of the respective pairs of the anvil members, the anvil members engage each other thereby effectuating switch closure.

10. The device as recited in 9, further comprising a standoff member for each of the anvil members, each of the standoff members are attached to the base and proximal to its respective anvil member,

whereby each of the anvil members are stabilized prior to a switching event during inertial loading of the switch.

11. The device as recited in 10, wherein each of the standoff members is a breakaway-type of member and distal ends of each of the standoff members has a break-off section that is substantially juxtaposed to the distal end of its respective anvil member.

12. The device as recited in 10, wherein each of the standoff members is a sprung-type movable member and distal ends of each respective pair of standoff member and anvil member cooperatively forms a cylinder-in groove coupling, thereby providing initial stabilization of the anvil member and subsequent translational movement thereof upon activation of the switching assembly.

13. The device as recited in 7, wherein the electrical switching assembly further includes a contact hammer standoff member that attaches to the base, the contact hammer standoff member has arms whose distal ends cooperatively form a cylinder-in groove coupling with a respective contact hammer leg member, thereby providing initial stabilization of the hammer members prior to activation of the switching assembly.

14. The device as recited in 7, wherein the electrical switching assembly further includes a contact hammer standoff member that attaches to the base, the contact hammer standoff member has arms whose distal ends cooperatively have break-off tab members with its respective contact hammer leg member, thereby providing initial stabilization of the hammer members prior to activation of the switching assembly.

15. The device as recited in 7, wherein the electrical switching assembly is a normally open, single-pole, single-throw switch.

16. The device as recited in 7, wherein the electrical switching assembly is a normally open, double-pole, single-throw switch.

17. The device as recited in 15, wherein the electrical switching assembly is a normally open, single-pole, single-throw switch and the switching assembly further includes an electrically shunt member that is attached to the base and the shunt member connects to at least two bonding pad members.

18. The device as recited in 7, wherein the head member of the shuttle member on each side has a catch engagement recess section that cooperatively engages and latches with each of the contact hammer members during inertial loading of the switching device.

19. A microelectromechanical switching device, the device comprising:

a base;

a sliding shuttle member slidably mounted on the base;

an anchor assembly having at least one pair of flexible anchor legs attached to the shuttle member wherein the at least one pair of the anchor legs cooperatively and slidably engages a pair of constriction members through at least one pair of movable anchor feet attached to distal ends of the anchor legs, the constriction members are attached to the base, and an electromechanical means for enabling the switching device that includes an electromechanical actuator and a movable linchpin, wherein the electromechanical actuator is attached to at least two electrical bonding pads, a first end of the linchpin member slidably moves within the electromechanical actuator and the other end of the linchpin slidably moves between the anchor feet; and

an electrical switching assembly that is attached to the base wherein the shuttle member has a head member that actuates the switching assembly when the switching device is subjected to inertial loading,

whereby when the electromechanical means is actuated, the linchpin slides out from between the anchor feet, thereby allowing the anchor feet to move towards each other and allowing the shuttle member to slide when the switching device is subjected to inertial loading.

20. A microelectromechanical switching device, the device comprising:

a base;

a sliding shuttle member that is slidably mounted on the base;

an anchor assembly having at least one pair of flexible anchor legs that are attached to the shuttle member wherein the at least one pair of anchor legs cooperatively and slidably engages constriction members through at least one pair of movable anchor feet that are attached to distal ends of each anchor leg, the constriction members are attached to the base, and mechanical means for enabling the switching device, the mechanical means includes a mechanical lift arm assembly that attaches to a support member for a lift arm, the lift arm attaches to a linchpin when the support member is moved by an external actuator means, the other end of the linchpin slidably moves between the anchor feet; and

an electrical switching assembly that is attached to the base wherein the shuttle member has a head member that actuates the switching assembly when the switching device is subjected to inertial loading,

whereby when the mechanical means is actuated, the linchpin slides out from between the anchor feet, thereby allowing the anchor feet to move towards each other and allowing the shuttle member to slide when the switching device is subjected to inertial loading.