A deployable multi-section boom comprising a first hinge assembly including a base section adapted to be attached to a structure, a movable section that is pivotably attached to the base section and a first boom attached to the movable section. The first hinge assembly is configured to allow the first boom to pivot in a first direction to a first predetermined maximum angle with respect to the base section. A first constant torque assembly constantly urges the first boom to pivot in the first direction and includes a component attached to the base section of the first hinge assembly. The multi-section boom includes a second hinge assembly that includes a first section attached to the first boom and a second section that is pivotably attached to the first section. A second boom is attached to the second section of the second hinge assembly wherein the second hinge assembly allows the second boom to pivot in a second direction to a second predetermined maximum angle with respect to the first boom. A second constant torque assembly constantly urges the second boom to pivot in the second direction and includes a component that is attached to the first section of the second hinge assembly. The first constant torque assembly and second constant torque assembly cooperate to configure the multi-section boom in a fully deployed state wherein the constant torque applied to the first boom causes the entire multi-section boom to pivot in the first direction while the constant torque applied to the second boom causes the second boom to simultaneously pivot in the second direction with respect to the first boom while the entire multi-section boom continues to pivot in the first direction. The multi-section boom is fully deployed when the first boom pivots to the first predetermined maximum angle and the second boom pivots to the second predetermined angle.

CROSS REFERENCE TO OTHER PATENT APPLICATIONS

FIELD OF THE INVENTION

The present invention relates to a deployable multi-section boom.

BACKGROUND

Deployable booms are typically used with spacecraft such as satellites for the purpose of deploying instruments and sensors that collect certain types of scientific data. It is very common to have one or more booms extending from a satellite wherein each boom carries a specific instrument or sensor, e.g. magnetometer. It is important that the distance between the spacecraft and the instruments and/or sensors be sufficient to prevent interference with the operation of the instruments and/or sensors from electrical, magnetic and/or nuclear radiation emanating from the satellite. Thus, the maximum length of a fully deployed boom is a critical factor in obtaining undistorted scientific data from instrumentation or sensors. It is also a requirement that a deployable boom be compact enough to be stowed within a small volume within the spacecraft but yet be robust enough to withstand high launch loads. Furthermore, the deployable boom must be capable of deploying from a stowed state to a stable, elongated, rigid structure without losing any structural integrity during deployment. Therefore, what is needed is a new and improved deployable boom having a structure that not only has the aforementioned desired characteristics but is also lightweight, uses relatively fewer components when compared to conventional deployable booms and is relatively inexpensive to manufacture.

SUMMARY OF THE INVENTION

In one aspect, the present invention is directed to a deployable multi-section boom. In an exemplary embodiment, the deployable multi-section boom of the present invention includes a first hinge assembly that includes a base section adapted to be attached to a structure, such as a spacecraft, and a movable section that is pivotably attached to the base section. The multi-section boom includes a first or lower boom attached to the movable section of the first hinge assembly. The first hinge assembly is configured to allow the first boom to pivot in a first direction to a first predetermined maximum angle with respect to the base section. The multi-section boom further includes a first constant torque assembly to constantly urge the first boom to pivot in the first direction. The first constant torque assembly includes a component attached to the base section of the first hinge assembly. The multi-section boom further includes a second hinge assembly that includes a first section attached to the first boom and a second section that is pivotably attached to the first section. The multi-section boom further includes a second or upper boom that has a first end that is attached to the second section of the second hinge assembly. The second hinge assembly is configured to allow the second boom to pivot in a second direction to a second predetermined maximum angle with respect to the first boom. The multi-section boom further includes a second constant torque assembly that constantly urges the second boom to pivot in the second direction. The second constant torque assembly includes a component that is attached to the first section of the second hinge assembly. The first constant torque assembly and second constant torque assembly cooperate to configure the multi-section boom to a fully deployed state wherein the constant torque applied to the first boom causes the entire multi-section boom to pivot in the first direction while the constant torque applied to the second boom causes the second boom to simultaneously pivot in the second direction while the entire multi-section boom continues to pivot in the first direction. The multi-section boom is fully deployed when the first boom pivots to the first predetermined maximum angle and the second boom pivots to the second predetermined angle.

In another aspect, the present invention relates to a spacecraft comprising a spacecraft body and a deployable multi-section boom movable attached to the spacecraft body and configurable to a fully deployed state from an initial stowed state. In an exemplary embodiment, the deployable multi-section boom includes a first hinge assembly having a base section attached to the spacecraft body and a movable section that is pivotably attached to the base section. The multi-section boom further includes a first or lower boom attached to the movable section of the first hinge assembly. The first hinge assembly is configured to allow the first boom to pivot in a first direction to a first predetermined maximum angle with respect to the base section. The multi-section boom further comprises a first constant torque assembly to constantly urge the first boom to pivot in the first direction. The first constant torque assembly includes a component attached to the base section of the first hinge assembly. The multi-section boom further includes a second hinge assembly having a first section attached to the first boom and a second section that is pivotably attached to the first section. A second or upper boom is attached to the second section of the second hinge assembly. The second hinge assembly is configured to allow the second boom to pivot in a second direction to a second predetermined maximum angle with respect to the first boom. The multi-section boom further includes a second constant torque assembly to constantly urge the second boom to pivot in the second direction. The second constant torque assembly includes a component that is attached to the first section of the second hinge assembly. The spacecraft body includes a release mechanism having a release plate releasably attached thereto. The release mechanism is configurable to a first state wherein the release plate is retained by the release mechanism and to a second state wherein the release plate is released by the release mechanism. The second boom is configured to engage the release plate. When the multi-section boom is initially in the stowed configuration, the release mechanism is in the first state and the second boom is in juxtaposition with the first boom such that the release plate is engaged with the second boom. The spacecraft body includes a lip for engaging an extending portion of the second boom in order to maintain the multi-section boom in the stowed state. When the release mechanism is configured to the second state, the release plate is released thereby allowing the torque created by the second constant torque assembly to cause the second boom to pivot in the second direction so that the extending portion of the second boom becomes free of the lip. When the extending portion of the second boom is completely free of the lip, the torque created by the first constant torque assembly causes the first boom, and thus the entire multi-section boom, to pivot in the first direction while the second boom simultaneously pivots in the second direction with respect to the first boom. The multi-section boom is fully deployed when the first boom pivots to the first predetermined maximum angle and the second boom pivots to the second predetermined maximum angle with respect to the first boom.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

As used herein, the term “structure” refers to the physical structure, or portion thereof, of an object or body including spacecraft, machine or machinery, robots, automobiles, trucks and other road vehicles, remote-controlled vehicles, drones, unmanned aerial vehicles (UAV), airplanes, ships, submarines, underwater drones and trains.

As used herein, the term “spacecraft” refers to any type of spacecraft used in space or space applications and includes satellites, CubeSats, space stations, capsules, rockets, probes, pods, planetary rovers and other space exploration vehicles.

The concept and operation of deployable multi-section boom20of the present invention are illustrated inFIGS. 1-5. The views of the deployable multi-section boom20shown inFIGS. 1-5are simplified in order to facilitate understanding of the basic concept of the invention. Therefore, several components of deployable multi-section boom20are not shown inFIGS. 1-5but are shown in detail in other drawings herein. Deployable multi-section boom20of the present invention is used with structure22. In an exemplary embodiment, structure22comprises a spacecraft which includes spacecraft body24. Multi-section boom20is movably attached to spacecraft body24and configurable to a fully deployed state from an initial stowed state. In an exemplary embodiment, deployable multi-section boom includes first hinge assembly30which has base section32adapted to be attached to spacecraft body24and movable section34that is pivotably attached to base section32. In a preferred embodiment, isolator36is positioned between base section32and spacecraft body24. Isolator36electrically isolates multi-section boom20from spacecraft body24because spacecraft body24is part of the spacecraft's electrical ground system. Hence, isolator36minimizes or eliminates any electrical current flowing into multi-section boom20thereby minimizing or eliminating magnetic fields on multi-section boom20. In an exemplary embodiment, movable section34comprises a hinge shaft. First hinge assembly30further includes portion37that functions as the hinge knuckle (seeFIG. 6). Hinge shaft34passes through hinge knuckle37. Multi-section boom20further includes a first or lower boom40that is attached to the movable section34of first hinge assembly30. First boom40has slot42therein that extends there-through as shown inFIG. 6. First hinge assembly30is configured to allow first boom40to pivot in a first direction indicated by arrow44to a first predetermined maximum angle with respect to base section32as shown inFIGS. 2-4. Base section32includes raised stop-structure46that is shaped to limit or stop the pivotal movement of first boom40at the first predetermined maximum angle. Thus, when first boom40is pivoted in the first direction44to the first predetermined maximum angle, portion48of first boom40physically contacts raised stop structure46(seeFIGS. 2, 3 and 5). The specific size, shape and structure of raised stop-structure46and/or portion48are configured to provide a first predetermined maximum angle of about 180°. It is to be understood that raised stop-structure46and/or portion48may be configured to have different sizes and/or structures so as to provide a first predetermined maximum angle other than 180°. Referring toFIG. 6, multi-section boom20further comprises a first constant torque assembly for constantly urging first boom40to pivot in the first direction44. The first constant torque assembly includes component50that is attached to base section32of first hinge assembly30. The first constant torque assembly is discussed in detail in the ensuing description.

Referring toFIGS. 1-5 and 7, multi-section boom20further includes a second hinge assembly, indicated by reference number60, which includes first section62that is attached to first boom40and second section64that is pivotably or movably attached to first section62. Multi-section boom20further includes a second or upper boom70. Second boom70has first end portion71that is attached to second section64of second hinge assembly60. End portion71includes an extending portion150. Extending portion150includes edge portion151. Second hinge device60is configured to allow second boom70to pivot in a second direction72with respect to first boom40to a second predetermined maximum angle. In an exemplary embodiment, second section64of second hinge device60comprises a hinge shaft. First section62functions as a hinge knuckle and receives hinge shaft64. First section62may be integral with first boom40or may be a separate structure that is attached or fixed to first boom40. Referring toFIG. 7, portion151of extending portion150physically contacts the surface43of first boom40when second boom70has pivoted in the second direction72to the second predetermined maximum angle. The shape, size and structure of portion151and/or surface43are configured to provide a desired second predetermined maximum angle. Thus, in an exemplary embodiment, the shape, size and structure of portion151and/or surface43are configured to provide a second predetermined maximum angle of 180°. However, it is to be understood that the shape, size and structure of portion151and/or surface43may be configured to achieve a second predetermined maximum angle other than 180°. Multi-section boom20further includes a second constant torque assembly that constantly urges second boom70to pivot in second direction72(seeFIG. 7). The second constant torque assembly includes component80that is attached to first section62of second hinge assembly60. The second constant torque assembly is discussed in detail in the ensuing description. Second boom70further includes an opposite second end to which a scientific instrument200may be attached. Scientific instrument200is discussed in detail in the ensuing description.

Referring toFIGS. 1, 2 and 7-11, spacecraft body24includes release mechanism90that is operable with release plate92. Release mechanism90is shown in phantom inFIGS. 1-5. In an exemplary embodiment, release mechanism90and release plate92are configured as the release mechanism and release block, respectively, that are shown inFIGS. 13 and 12Bof U.S. Pat. No. 9,546,008, entitled “Miniature Release Mechanism Or Diminutive Assembly For Nanosatellite Deployables (DANY)”, the disclosure of which patent is incorporated herein by reference. However, it is to be understood that release mechanism90and release plate92may be realized by other suitable devices. Release mechanism90is configurable in a first state wherein release mechanism90retains release plate92and in a second state wherein release mechanism90releases the release plate92. As shown inFIG. 8, release plate92includes two passages94for receiving corresponding pins of release mechanism90. When the corresponding pins of release mechanism90are inserted into passages94, the release plate92is secured to release mechanism90. In an exemplary embodiment, release plate92includes passage96oriented in the same direction as passages94. Passage96is sized to receive a corresponding pin120positioned within slot122in upper boom70(seeFIGS. 5 and 12). When multi-section boom20is in the stowed state, as shown inFIG. 1, second boom70is in juxtaposition to first boom40such that release plate92, while still secured to release mechanism90, extends through slot42of first boom40and into slot122of second boom70such that pin120passes through passage96. Thus, when multi-section boom20is in the stowed position, corresponding pins of release mechanism90pass through passages94of release plate92and pin120in upper boom70passes through passage96of release plate92. As shown inFIG. 7, extending portion150that extends a predetermined distance beyond first section62of second hinge assembly60. Spacecraft body24includes retainer or lip152that engages extending portion150so as to maintain multi-section boom20in the stowed state as shown inFIG. 1. Lip152passively restrains second hinge assembly60without the need of additional release mechanisms. When release mechanism90is activated, the pins (not shown) of release mechanism90are withdrawn from passages94thereby releasing the release plate92from release mechanism90. Once release plate92is released, the torque created by the second constant torque assembly causes second boom70to pivot in the second direction72. As second boom70pivots in the second direction72, extending portion150becomes disengaged or free from lip152. When extending portion150is free of lip152, the torque created by the first constant torque assembly causes first boom40, and thus the entire multi-section boom20, to pivot in first direction44while second boom70simultaneously pivots in second direction72with respect to first boom40. Multi-section boom20is fully deployed when first boom40pivots to the first predetermined maximum angle and second boom70pivots to the second predetermined maximum angle. In an exemplary embodiment, the first predetermined maximum angle is 180° and the second predetermined maximum angle is 180°. In order to stow multi-section boom20, first boom40must first be pivoted back toward spacecraft body24in order to close first hinge assembly30and thereafter, second boom70is pivoted toward first boom40until extending portion150is engaged by lip152and second boom70is in juxtaposition with first boom40as shown inFIG. 1such that release plate92is inserted into slot42and back into release mechanism92. Release mechanism92may have to be reconfigured, reset or replaced prior to the re-stowage of deployable multi-section boom20. In an alternate embodiment, deployable multi-section boom20is configured for a one-time deployment such that when multi-section boom20is deployed, it remains deployed and does not return to the stowed state.

In another embodiment, release plate92is rigidly attached to second boom70. In such an embodiment, second boom70is configured without pin120and slot122. In this embodiment, the release plate92still operates with release mechanism90as described in the foregoing description.

As shown inFIGS. 3-6, the first constant torque assembly constantly urges first boom40to pivot in the first direction44. The first constant torque assembly includes component50that is attached to base section32of first hinge assembly30. Component50comprises a spool or drum that has a substantially cylindrical shape, a circumference and exterior surface52that extends about the circumference. Spool50includes a longitudinally extending axis and an internal bore or passage (not shown) that extends in the same direction as the longitudinally extending axis of spool50. The bore is sized for receiving a portion of hinge shaft34(seeFIG. 1) such that spool50supports this portion of hinge shaft34. In an exemplary embodiment, the bore of spool50is substantially coaxial with the longitudinally extending axis of spool50. Hinge shaft34is shown in phantom inFIG. 10. In an exemplary embodiment, spool50is rigidly fixed to base section32of first hinge assembly30. The first constant torque assembly further includes constant torque spring160which has a first portion162thereof wrapped about at least a portion of exterior surface52of spool50and second portion164that extends in a direction that is tangential to the circumference of spool50. In an exemplary embodiment, constant torque spring160is a multi-layered constant spring which allows for easy addition or subtraction of overall torque by adding or removing spring leaves. In another embodiment, constant torque spring160is configured as a bi-stable tape spring. The first constant torque assembly further includes roller assembly166which has roller member168which is rotatably attached to first boom40and in an abutting relationship with second portion164of constant torque spring160such that constant torque spring160exerts a constant force on roller member168so as to urge first boom40to pivot in first direction44with respect to base section32. As first boom40pivots in first direction44, roller member168rolls over second portion164of constant torque spring160. Roller assembly166further includes shaft170that is mounted or attached to first boom40. Roller member168rotates about the shaft170. Clip172retains shaft170on first boom40. A second clip (not shown) that is similar to clip172is used to retain roller member168on shaft170. As shown inFIGS. 9 and 10, second portion164curls about roller member168as first boom40pivots in first direction44.

Referring toFIG. 6, multi-section boom20further includes harness drum180attached to first boom40for supporting a portion of hinge shaft34and is positioned such that first boom40is between spool50and harness drum180. In an exemplary embodiment, screws181are used to attach harness drum180to first boom40. However, other suitable fastener means, devices or techniques may be used to attach harness drum180to lower boom40. In an exemplary embodiment, harness drum180is substantially cylindrical in shape and has a longitudinally extending axis that is substantially coaxial with hinge shaft34. Harness drum180includes an internal bore or passage (not shown) that is sized for receiving a portion of hinge shaft34. In an exemplary embodiment, the bore in harness drum180is substantially coaxial with the longitudinally extending axis of harness drum180. Referring toFIGS. 12 and 13, the cylindrical shape of harness drum180allows harness201to be secured to harness drum180. Harness201is wrapped or looped around harness drum180in a single loop. Harness201is further discussed in the ensuing description.FIGS. 1-5do not show harness drum180in order to simplify the views for the purpose of facilitating understanding of the invention.

Referring toFIGS. 7, 9 and 11, the second constant torque assembly includes component80that is attached to first section62of second hinge device60. In an exemplary embodiment, component80comprises a spool or drum that has a substantially cylindrical shape, a circumference and exterior surface82that extends about the circumference of spool80. Spool80includes a longitudinally extending axis and an internal bore or passage (not shown) that extends in the same direction as the longitudinally extending axis of the spool80. The bore of spool80is sized for receiving a portion of second hinge shaft64so as to allow spool80to support that portion of second hinge shaft64. InFIG. 11, second hinge shaft64is shown in phantom. In an exemplary embodiment, the bore of spool80is substantially coaxial with the longitudinally extending axis of spool80. The second constant torque assembly includes second constant torque spring204. In an exemplary embodiment, constant torque spring204is a multi-layered constant spring which allows for easy addition or subtraction of overall torque by adding or removing spring leaves. In another embodiment, constant torque spring204is configured as a bi-stable tape spring. Second constant torque spring204includes first portion206that is wrapped about at least a portion of exterior surface82of spool80and second portion208that extends in a direction that is tangential to the circumference of spool80. The second constant torque assembly further includes roller assembly210which includes roller member212. Roller member212is rotatably attached or secured to second boom70. Roller member212is in an abutting relationship with second portion208of second constant torque spring204such that second constant torque spring204exerts a constant force or torque on roller member212so as to urge second boom70to pivot in second direction72with respect to first boom40. As second boom70pivots in second direction72, roller member212rolls over second portion208of second constant torque spring204as shown inFIG. 11. Roller assembly210further includes shaft214that is attached or secured to second boom70. Roller member212rotates about shaft214. Clip215retains roller member212on shaft214. Another clip (not shown) that is similar to clip215is used to retain shaft214on upper boom70. The second constant torque device further includes torque spring adapter216that is attached to first boom40. Torque spring adapter216holds spool80and constant torque spring204in place. In an exemplary embodiment, one or more screws217are used to attach torque spring adapter216to spool80. In an exemplary embodiment, screws218and washers220are used to attach torque spring adapter216to lower boom40. However, it is to be understood that other techniques and/or fasteners may be used to attach torque spring adapter216to lower boom40, e.g. rivets, welding, brazing, etc. As shown inFIG. 11, second portion208of constant torque spring204curls about roller member212as second boom70pivots in second direction72to the second predetermined maximum angle.

Referring toFIG. 7, multi-section boom20further includes harness drum250that is attached to second boom70for supporting a portion of second hinge shaft64and positioned such that second boom70is between spool80and harness drum250. In an exemplary embodiment, harness drum250is attached to second boom70via screws (not shown). However, it is to be understood that other suitable techniques and/or fasteners may be used to attach harness drum250to second boom70. In an exemplary embodiment, harness drum250is substantially cylindrical in shape and has a longitudinally extending axis that is substantially coaxial with second hinge shaft64. Harness drum250includes an internal bore or passage (not shown) that is sized for receiving a portion of hinge shaft64. In an exemplary embodiment, the bore of harness drum250is substantially coaxial with the longitudinally extending axis of harness drum250. The cylindrical shape of harness drum250allows harness201to be secured to harness drum250. As shown inFIGS. 12 and 14, harness201is wrapped or looped around harness drum250in a single loop. Harness201is further discussed in the ensuing description. For purposes of simplifying the view ofFIG. 12, structure22, release mechanism90and release plate92are not shown.

Harness201houses electrical wires that are in electrical signal communication with scientific instrument200that is attached to the opposite second end of second boom70as shown inFIGS. 1-5 and 12. Instrument200may be any one of a variety of instruments including a 3-axis magnetometer, temperature sensor, thermistor, probe, camera, radiation detector, etc. If a 3-axis magnetometer is attached to multi-section boom20, then preferably the 3-axis magnetometer includes thermal tape to maintain healthy temperatures on-orbit. Referring toFIGS. 12-14, harness201is wrapped about each harness drum180and250in a single loop to provide strain relief, minimize the torque required to overcome the forces produced by bending harness201and to provide a flexible joint. Such a configuration minimizes restrictive forces especially within cold environments. Harness201is also secured to first boom40and second boom70by clamp members202and harness guides203that are attached to the sides of first boom40and second boom70. Clamp members202provide further strain relief for harness201. Each clamp member202includes first section202A, second section202B and screw or fastener202C which attaches first section202A and second section202B together. Harness201is clamped between first section202A and202B. Clamp members202and harness guides203may be attached to the sides of first boom40and second boom70by screws205or any other suitable fasteners or techniques, e.g. bolts, rivets, welding, brazing, etc.

In an exemplary embodiment, multi-section boom20is configured to have a length that is over 50 centimeters when multi-section boom20is fully deployed. In an exemplary embodiment, multi-section boom20has a length of 52 centimeters when multi-section boom20is fully deployed. Thus, the miniaturized size of multi-section boom20allows it to be used with CubeSats or other miniaturized space craft.

First constant torque spring160and second constant torque spring204provide a sufficient torque margin during the entire articulation of the deployment of multi-section boom20and also provides a strong positive torque at the end for stiffness without needing a positive latch. Thus, constant torque springs160and204provide sufficient torque to overcome deployment forces with sufficient remaining torque to maintain multi-section boom20in a deployed state.

In an exemplary embodiment, constant torque springs160and204are fabricated from stainless steel and a de-gaussing process is used to remove or minimize magnetic residuals in the stainless steel. All other metallic portions of multi-section boom20are preferably fabricated from magnetically clean materials and are chosen from the group including, but not limited to, aluminum, brass, titanium, G10 and phosphorous bronze, ceramics and composite materials. In an exemplary embodiment, the hinge shafts34and64are made from titanium. In a preferred embodiment, multi-section boom20is mostly anodized.

Although the foregoing description is in terms of the deployable multi-section boom being used with spacecraft, it is to be understood that the multi-section boom may be used with other devices including, but not limited to, vehicles, robots including robotic devices used by law-enforcement or military bomb-disposal units and fail-safe laboratory equipment, etc.

The preceding description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications. Various modifications to these embodiments will readily be apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or the scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the following claims and the principles and novel features disclosed herein. Any reference to claim elements in the singular, for example, using the articles “a”, “an” or “the” is not to be construed as limiting the element to the singular.