# US 2014/0190677 A1 · Thermal straps for spacecraft

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- Number: US 2014/0190677 A1
- Document ID: US20140190677A1
- Status: Published application
- Kind: A1
- Application number: 14/155,977
- Filed: 2014-01-15
- Published: 2014-07-10
- Earliest claimed: 2012-08-16
- Assignees: Minus K. Technology, Inc.
- Applicants: Minus K. Technology, Inc.
- Inventors: David L. Platus; Erik K. Runge
- Web page: https://patentgrep.com/patent/US20140190677A1

## CPC

- F28F 9/26: Arrangements for connecting different sections of heat-exchange elements, e.g. of radiators (connecting different sections in water heaters F24H9/14 {, connecting headers with inlet or outlet fittings F28F9/0246})
- B64G 1/50: for temperature control
- F16F 15/04: using elastic means (single elements or their attachment F16F1/00 - F16F13/00); {(F16F15/023, F16F15/03 take precedence)}
- F25D 19/006: {Thermal coupling structure or interface}
- F28F 13/00: Arrangements for modifying heat-transfer, e.g. increasing, decreasing (F28F1/00 - F28F11/00 take precedence)
- B64G 1/228: {Damping of high-frequency vibration effects on spacecraft elements, e.g. by using acoustic vibration dampers}
- F16F 2228/063: Negative stiffness
- F28D 2021/0021: {for aircrafts or cosmonautics}
- F28F 2013/006: {Heat conductive materials}
- F28F 2255/02: Flexible elements
- F28F 2265/26: for allowing differential expansion between elements
- F28F 2265/30: for preventing vibrations
- F28F: DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION (water and air traps, air venting F16)
- B64G: COSMONAUTICS; VEHICLES OR EQUIPMENT THEREFOR
- F16F: SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
- F25D: REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR (refrigerated showcases A47F3/04; thermally-insulated vessels for domestic use A47J41/00; refrigerated vehicles, see the appropriate subclasses of classes B60 - B64; containers with thermal insulation in general B65D81/38; heat-transfer, heat-exchange or heat-storage materials, e.g. refrigerants, or materials for the production of heat or cold by chemical reactions other than by combustion C09K5/00; thermally-insulated vessels for liquefied or solidified gases F17C; air-conditioning or air-humidification F24F; refrigeration machines, plants, or systems F25B; cooling of instruments or comparable apparatus without refrigeration G12B)
- F28D: HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT (fluid heaters having heat generating means and heat transferring means F24H; furnaces F27; details of heat-exchange apparatus of general)

## Abstract

Negative-stiffness-producing mechanisms can be incorporated with structural devices that are used on spacecraft that provide thermal coupling between a vibrating source and a vibration-sensitive object. Negative-stiffness-producing mechanisms can be associated with a flexible conductive link (FCL) or “thermal strap” or “cold strap” to reduce the positive stiffness of the FCL. The negative-stiffness-producing mechanisms can be loaded so as to create negative stiffness that will reduce or negate the natural positive stiffness inherent with the FCL. The FCL will still be able to provide maximum thermal conductance while achieving low or near-zero stiffness to maximize structural decoupling.

## Claims

### Claim 1

A negative-stiffness thermal strap comprising:
a thermal strap which provides thermal coupling and structural decoupling between a vibration-sensitive object and a vibrating cooling source, the thermal strap having positive axial stiffness and positive tilt stiffness; and
an axial-tilt negative-stiffness-producing mechanism which is connected to the thermal strap and acts on the thermal strap to reduce some of its positive axial stiffness and positive tilt stiffness.

### Claim 2 (depends on 1)

The negative-stiffness thermal strap of claim 1, wherein the thermal strap has positive transverse stiffness and the negative thermal strap includes a transverse negative-stiffness-producing mechanism which is connected to the thermal strap and acts on the thermal strap to reduce some of its positive transverse stiffness.

### Claim 3 (depends on 2)

The negative-stiffness thermal strap of claim 2, wherein the axial-tilt negative-stiffness-producing mechanism and transverse negative-stiffness-producing mechanism are connected in series.

### Claim 4 (depends on 1)

The negative-stiffness thermal strap of claim 1, wherein the axial-tilt negative-stiffness producing mechanism includes three axially-compressed circumferentially-oriented flexures that are circumferentially spaced at 120°.

### Claim 5 (depends on 2)

The negative-stiffness thermal strap of claim 2, wherein the transverse negative-stiffness-producing mechanism includes a plurality of axially compressed beam-columns oriented in an axial direction.

### Claim 6 (depends on 3)

The negative-stiffness thermal strap of claim 3, wherein the transverse negative-stiffness-producing mechanism includes a plurality of axially compressed beam-columns oriented in an axial direction.

### Claim 7 (depends on 1)

The negative-stiffness thermal strap of claim 1, wherein the axial-tilt negative-stiffness-producing mechanism includes at least one axially-compressed flexure that is oriented in a transverse direction.

### Claim 8 (depends on 6)

The negative-stiffness thermal strap of claim 6, wherein the axial-tilt negative-stiffness producing mechanism includes three axially-compressed circumferentially-oriented flexures that are circumferentially spaced at 120°.

### Claim 9 (depends on 1)

The negative-stiffness thermal strap of claim 1, wherein the axial-tilt negative-stiffness-producing mechanism is thermally isolated from the thermal strap.

### Claim 10 (depends on 2)

The negative-stiffness thermal strap of claim 2, wherein the transverse negative-stiffness-producing mechanism is thermally isolated from the thermal strap.

### Claim 11 (depends on 1)

The negative-stiffness thermal strap of claim 1, wherein the axial-tilt negative-stiffness-producing mechanism is made from a material that has relatively low thermal conductivity relative to the material used to make the thermal strap.

### Claim 12 (depends on 2)

The negative-stiffness thermal strap of claim 2, wherein the transverse negative-stiffness-producing mechanism is made from a material that has relatively low thermal conductivity relative to the material used to make the thermal strap.

### Claim 13 (depends on 3)

The negative-stiffness thermal strap of claim 3, wherein the axial-tilt negative-stiffness-producing mechanism is thermally isolated from the thermal strap and the transverse negative-stiffness-producing mechanism is thermally isolated from the thermal strap.

### Claim 14

A negative-stiffness flexible conductive link which provides thermal coupling between a vibration-sensitive object and a vibrating cooling source, comprising:
three flexible conductive links, each flexible conductive links having positive axial stiffness, positive transverse stiffness and positive tilt stiffness;
an axial-tilt negative-stiffness-producing mechanism which acts on each of the flexible conductive links to reduce the composite positive axial stiffness and positive tilt stiffness of the flexible conductive links; and
a transverse negative-stiffness-producing mechanism which acts on each of the flexible conductive links to reduce the composite positive transverse stiffness of the flexible conductive links.

### Claim 15 (depends on 14)

The negative-stiffness flexible conductive link of claim 14, wherein the axial-tilt negative-stiffness-producing mechanism includes at least one flexure that is oriented in a transverse direction and is coupled to the flexible conductive links, and the axial-tilt negative-stiffness-producing mechanism is designed to apply a compressive force on the at least one flexure.

### Claim 16 (depends on 14)

The negative-stiffness flexible conductive link of claim 14, wherein the transverse negative-stiffness-producing mechanism includes a plurality of axially compressed beam-columns oriented in the axial direction.

### Claim 17 (depends on 14)

The negative-stiffness flexible conductive link of claim 14, wherein the three flexible conductive links are circumferentially spaced at 120°.

### Claim 18 (depends on 17)

The negative-stiffness flexible conductive link of claim 17, wherein the axial-tilt negative-stiffness producing mechanism includes three axially-compressed circumferentially-oriented flexures that are circumferentially spaced at 120°.

### Claim 19 (depends on 18)

The negative-stiffness flexible conductive link of claim 18, wherein each of the three flexible conductive links is placed between adjacent flexible conductive links.

### Claim 20 (depends on 14)

The negative-stiffness flexible conductive link of claim 14, wherein the axial-tilt negative-stiffness-producing mechanism and the transverse negative-stiffness-producing mechanism are thermally isolated from the conductive links.

### Claim 21 (depends on 14)

The negative-stiffness flexible conductive link of claim 14, wherein the axial-tilt negative-stiffness-producing mechanism and the transverse negative-stiffness-producing mechanism are made from materials that have relatively low thermal conductivity relative to the material used to make the conductive links.

### Claim 22

The improvement of structural decoupling between a vibration-sensitive object and a vibrating source connected by a flexible link in a zero gravity environment by the addition of a axial-tilt negative-stiffness-producing mechanism that acts on the flexible link and removes some or all of the positive axial and tilt stiffness of the flexible link.

### Claim 23 (depends on 21)

The improvement of claim 21, further including the addition of a transverse negative-stiffness-producing mechanism that acts on the flexible link and removes some or all of the positive transverse stiffness of the flexible link.