HINGE

Abstract

A hinge (1) attaches between two elements (4) in a deployable structure. The hinge (1) includes support members (2) for attaching to or forming part of the elements (4). The hinge (1) also includes two gears (8) in mesh with each other, each gear (8) attached to a support member (2), with the gears (8) rotating about parallel axes. The hinge also includes a tape spring (16) attached to and extending between the support members (2). The tape spring (16), when extended longitudinally, lies substantially in a plane parallel to the axes of the gears. The tape spring (16) is arranged to actuate the hinge from a folded configuration towards an extended configuration. The hinge (1) also includes a retaining member (18) attached to the gears (8) and/or the support members (2). The retaining member (18) is arranged to restrict the separation of the gears (8) in a direction extending between the axes of the gears.

Claims

1-17. (canceled)

18. A hinge for attachment between two elements in a deployable structure, the hinge comprising: two support members each for attaching to or forming part of an element of the two elements of the deployable structure; two gears in mesh with each other, each gear being attached to a respective one of the two support members, having a rotational axis, and being configured for rotation about its respective rotational axis, with the rotational axis of each gear being parallel to one another; at least one tape spring attached to and extending between the support members, the at least one tape spring when extended longitudinally in a direction perpendicular to the rotational axes of the gears lying substantially in a plane parallel to the rotational axis of each gear, and the at least one tape spring being configured to actuate the hinge from a folded configuration in which the at least one tape spring is bent along a direction parallel to the rotational axis of each gear toward an extended configuration in which the at least one tape spring is extended longitudinally; and a retaining member attached to one or both of the gears and the support members, the retaining member being arranged to restrict separation of the gears in a direction extending between the rotational axes of the gears.

19. The hinge as claimed in claim 18, wherein each gear has an axle, and the retaining member is attached to and extends between the axles of the gears.

20. The hinge as claimed in claim 18, wherein the retaining member is configured to restrict movement of the gears in directions outside a plane perpendicular to the rotational axis of each gear.

21. The hinge as claimed in claim 20, wherein the retaining member is configured to restrict movement of the gears in directions out of a plane perpendicular to the axes of the gears by less than 1 degree.

22. The hinge as claimed in claim 18, wherein each gear is attached to a respective one of the support members at a side of the gear opposed to teeth of the gear by which the gears are in mesh with each other.

23. The hinge as claimed in claim 18, wherein each support member is longitudinally extended, having one end for attaching to a respective element of the two elements of the deployable structure and an opposite end for attaching to a respective one of the gears.

24. The hinge as claimed in claim 18, wherein each gear includes teeth provided around an arc of a circumference of the gear, wherein the arc subtends an angle of between 80 and 140 degrees.

25. The hinge as claimed in claim 18, wherein the hinge is configured such that, in the extended configuration of the hinge, the at least one tape spring is allowed to extend into a fully longitudinally extended configuration such that the at least one tape spring is arranged to lock.

26. The hinge as claimed in claim 18, wherein the at least one tape spring comprises a plurality of tape springs.

27. The hinge as claimed in claim 26, wherein tape springs of the plurality of tape springs are arranged to be parallel to each other and spaced from each other in a direction perpendicular to planes in which the tape springs lie substantially.

28. The hinge as claimed in claim 18, further comprising a release mechanism for holding the hinge in the folded configuration and configured to release the hinge such that the at least one tape spring actuates the hinge towards its extended configuration.

29. The hinge as claimed in claim 18, further comprising an opening stop configured to prevent the hinge from opening greater than a predetermined opening angle.

30. The hinge as claimed in claim 29, wherein the opening stop is configured to allow the at least one tape spring to lock, but to prevent the hinge from opening substantially any further than the opening angle at which the tape spring locks.

31. The hinge as claimed in claim 18, further comprising a closing stop configured to prevent the hinge from being held together at less than a predetermined closing angle.

32. The hinge as claimed in claim 18, further comprising a bracing member that extends between two retaining members, the bracing member being configured to restrict movement of the two sets of gears relative to each other.

33. The hinge as claimed in claim 18, wherein one gear set is arranged on a first side of the tape spring, and another gear set is arranged on a second side of the tape spring.

34. A hinge for attachment between two elements in a deployable structure, the hinge comprising: two sets of support members each for attaching to or forming part of an element of two elements of the deployable structure; two sets of two gears in mesh with each other, each gear set being attached to a respective set of support members of the two sets of support members, each gear set having a rotational axis, and the gears in each gear set being configured for rotation about its respective rotational axis, with the rotational axis of each gear set being parallel to one other; at least one tape spring attached to and extending between the support members, the at least one tape spring when extended longitudinally in a direction perpendicular to the rotational axes of the gear sets lying substantially in a plane parallel to the rotational axis of each gear, and the at least one tape spring being configured to actuate the hinge from a folding configuration in which the at least one tape spring is bent along a direction parallel to the rotational axis of each gear set toward an extended configuration in which the at least one tape spring is extended longitudinally; and two retaining members, each retaining member being attached to one or both of the gear sets and/or the support members, each retaining member being arranged to restrict separation of gears of the respective gear sets in a direction extending between the rotational axes of the respective gears.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0068] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0069] FIGS. 1a, 1b and 1c show an embodiment of a hinge in accordance with the present invention;

[0070] FIGS. 2a and 2b show a further embodiment of a hinge in accordance with the present invention; and

[0071] FIGS. 3a, 3b, 3c and 3d show the embodiment of the hinge shown in FIGS. 2a and 2b during different stages of deployment.

DETAILED DESCRIPTION

[0072] The embodiments of the hinge shown in the drawings are intended to be used to connect the elements in deployable structures such as antennas, solar panels, solar sails, etc., such that these interlinked elements are able to move in a coordinated fashion in order to deploy the structure. Such deployable structures, e.g. for launching into space are typically folded when launched and subsequently deployed when they reach their intended destination, e.g. orbit.

[0073] FIGS. 1a, 1b and 1c show a first embodiment of a hinge 1 in accordance with the present invention. The hinge 1 comprises two sets of two support members 2 (formed as struts) that each attach to respective elements 4 of a deployable structure (not shown) via a common mounting member 6, the hinge 1 being provided to allow rotation of the elements 4 relative to each other. At their other end, each of the support members 2 attaches to a respective gear 8.

[0074] The hinge thus comprises two sets of two spur gears 8, with each pair of gears comprising a gear support 12 and meshing together at the gear teeth 10. The gear teeth 10, which form an arc of 110 degrees around the circumference of each gear 8, are made of PEEK and attached to the respective gear support 12 with three screws 14. Using PEEK for the gear teeth 10 provides increased friction between the gear teeth 10 that helps to minimise any slipping between the gears 8 during deployment. The gear supports 12 are integrally moulded with the respective support member struts 2 from aluminium.

[0075] Each set of gear teeth 10 (and thus each gear 8) has the same radius of curvature and thus each set of two meshing gears has a gear ratio of 1.

[0076] Attached to, and extending between, each common mounting member 6 of the support are two tape springs 16 (not shown in FIG. 1a for the purposes of clarity). The tape springs 16 are made from Beryllium Copper and are attached parallel to each other on opposite sides of the mounting members 6. The tape springs 16 are attached to the mounting members 6 such that they each lie substantially in a plane perpendicular to the planes in which the gears 8 are arranged to rotate. The tape springs 16 each have a curved cross section (at least in their longitudinally extended configuration as shown in FIG. 1c) and are attached to the mounting members 6 such that their concave sides are facing each other.

[0077] The hinge 1 also comprises two retaining plates 18 (shown in outline only in FIG. 1a for the purposes of clarity) that are attached to either side of the hinge 1 and lie in planes parallel to the planes in which the gears 8 rotate. Integrally formed in each of the retaining plates 18 are two axles 20 for the respective pair of gears 8. The axles 20 extend in a direction perpendicular to the retaining plates 18 at the point at which the respective support member struts 2 attaches to the respective gear supports 12 and forms the axis about which each gear 8 rotates. The axles 20 thus form a plain bearing with the gear supports 12 and allow each pair of gears 8 to rotate relative to each other and the respective retaining plate 18, with the retaining plate 18 acting to maintain a constant distance between the axles 20 and thus the axes of rotation of the gears 8.

[0078] The attachment of the retaining plates 18 to the respective pair of gears 8 by means of the axles 20 integrally formed in the retaining plates 18 acts to constrain the rotation of the gears 8 to a plane perpendicular to their axles 20, and thus restrict the movement of the gears 8 in directions out of this plane.

[0079] Also integrally formed in each of the retaining plates 18 are a pair of stops 22 that project from the edge of the retaining plates 18, perpendicularly to the plane of the retaining plates 18 and are arranged to engage with the support members 2 when the hinge 1 is in is fully extended configuration, i.e. in the configuration shown in FIG. 1c. The stops 22 thus prevent the hinge 1 from opening out to an angle greater than that shown in FIG. 1c, thus preventing the tape springs 16 from overshooting their fully extended configuration.

[0080] Integrally formed with each of the two retaining plates 18 is a bracing member 24 that helps to keep the retaining plates 18 fixed in the same respective planes and thus helps to restrict the movement of the gears 8 in directions out of their planes of rotation. When the hinge is in its fully folded configuration (as shown in FIG. 1b) the bracing member 24 also acts as a stop to help prevent the hinge 1 from being folded beyond this position.

[0081] In operation, the hinge 1 is connected between, and thus interlinks, two elements 6 of a deployable structure. Before deployment, e.g. for launch on a spacecraft, the hinge 1 is folded into the folded configuration shown in FIG. 1b. In this configuration the tape springs 16, which are held at their respective two ends by the common mounting members 4, are bent along a direction parallel to the axes of the gears 8. When the tape springs 16 are bent like this, they possess an amount of stored strain energy. To counter this, and thus to retain the hinge 1 in its folded configuration during launch of the spacecraft, for example, before it is desired to be deployed, the hinge comprises a release mechanism (not shown as it is attached to the elements 4 of the deployable structure) for holding the hinge 1 (and thus the tape springs 16) in its folded configuration.

[0082] In the folded configuration (as shown in FIG. 1b) the bracing member 24 acts as a stop, engaging with the edges of the support members 2 to prevent the hinge 1 from being folded back further than the configuration shown in FIG. 1b, e.g. under the action of the release mechanism.

[0083] When the deployable structure (and therefore the hinge 1) is desired to be deployed, e.g. when the spacecraft reaches its destination, the release mechanism releases the hinge 1 such that stored strain energy of the tape springs 16 can be used to actuate the hinge 1 through the partly unfurled configuration shown in FIG. 1a and towards its fully extended configuration as shown in FIG. 1c.

[0084] This unfurling of the tape springs 16 acts to rotate the gears 8 of the hinge 1, via their connection to the support members 2 to which the tape springs 16 are attached, and thus actuates the hinge 1 from its folded configuration shown in FIG. 1b into its extended configuration shown in FIG. 1c. In this way, the actuation of the hinge 1 rotates the interlinked elements 6 of the deployable structure relative to each other to help deploy the deployable structure.

[0085] During the unfurling of the tape springs 16, the friction between the gear teeth 10 helps to control the deployment of the hinge 1, i.e. preventing it from unfolding too quickly. Also during unfurling, the retaining plates 18 (as well as the meshing gear teeth 10 to a lesser extent) act to constrain the rotation of the gears 8 within respective parallel planes and to restrict any movement of the gears 8 in directions out of these planes, which otherwise may be caused by the unpredictable movement (some of which may be out of plane) of the tape springs 16 during deployment.

[0086] This increased stiffness of the hinge 1 during deployment, owing to the action of the retaining plates 18, increases the accuracy and predictability of the hinge's 1 actuation by the tape spring 16 into its extended configuration.

[0087] When the tape springs 16 reach their fully extended configuration and the hinge 1 is opened fully, as shown in FIG. 1c, the stops 22 on the retaining plates 18 come into contact with the support member struts 2 to prevent the hinge 1 from opening beyond this position.

[0088] Once the tape springs 16 have unfurled fully and the hinge 1 has been opened fully into the extended configuration shown in FIG. 1c, the tape springs 16 lock along their length owing to the curvature of the tape springs 16 (in a direction perpendicular to the direction of longitudinal extension), thus holding the hinge 1 in its extended configuration shown in FIG. 1c. This locking of the tape springs 16, in addition to the action of the retaining plates 16, also increases the out of plane stiffness of the hinge 1 once it has been deployed, which thus increases the stiffness of the deployable structure of which it is a part.

[0089] A further embodiment of the invention will now be described with reference to FIGS. 2a and 2b.

[0090] FIGS. 2a and 2b show the front and reverse views of a second embodiment of a hinge 101 in accordance with the present invention. The overall design of this embodiment of the hinge 101 is similar to embodiment of the hinge shown in FIGS. 1a, 1b and 1c, in that it also comprises two mounting members 106 onto which respective elements of a deployable structure (not shown) are able to attach, and two tape springs 116 that attach to and extend between the opposite sides of the mounting members 106 from where the deployable structure elements attach.

[0091] However the embodiment of the hinge 101 shown in FIGS. 2a and 2b differs from the embodiment shown in FIGS. 1a, 1b and 1c in that the hinge 101 comprises only a single pair of spur gears 108 (having equal radius of curvature and therefore a gear ratio of 1) that are attached by respective support members 102, which are offset from the tape springs 116, to the respective mounting members 106. Each gear 108, corresponding support member 102 and corresponding mounting member 106 is integrally formed as a single piece from a 3D printed thermoplastic.

[0092] The two integrally formed pieces engage at the two sets of gear teeth 110 and are held together by a retaining member 118 that mounts onto axles 120 that project from, and are integrally formed with, the gears 108. The axles 120 thus form a plain bearing with the retaining member 118 and allow each pair of gears 108 to rotate relative to each other and the retaining member 118, with the retaining member 118 acting to maintain a constant distance between the axles 120 and thus the axes of rotation of the gears 108.

[0093] The two tape springs 116 are integrally formed from a carbon fibre composite, with cylindrical portions 117 formed at each end of the tape springs 116 that are each mounted coaxially onto corresponding cylindrical portions 119 that project from the mounting members 106.

[0094] As with the embodiment shown in FIGS. 1a, 1b and 1c, the attachment of the retaining member 118 to the pair of gears 108 by means of the axles 120 integrally formed in the gears 108 acts to constrain the rotation of the gears 108 to a plane perpendicular to their axles 120, and thus restrict the movement of the gears 108 in directions out of this plane.

[0095] Also integrally formed in the pair of gears 108 is a pair of stops 122 that project from the edge of the gears 108, at a tangent to the edge of the gears 108 and are arranged to engage with each other when the hinge 101 is in is fully extended configuration, i.e. in the configuration shown in FIGS. 2a and 2b. The stops 122 thus prevent the hinge 101 from opening out to an angle greater than that shown in FIG. 1c, thus preventing the tape springs 116 from overshooting their fully extended configuration.

[0096] A second pair of stops 124 are also integrally formed in the pair of gears 108 that project from the other side of the gears 108. These stops 124 are arranged to prevent the hinge 101 from being folded back further than the configuration shown in FIG. 3a, e.g. under the action of a release mechanism (not shown).

[0097] Operation of the hinge 101 shown in FIGS. 2a, 2b and 2c will now be described with additional reference to FIGS. 3a, 3b, 3c and 3d that show the hinge 101 in different stages of deployment.

[0098] The operation of this embodiment of the hinge 101 is very similar to that of the embodiment shown in FIGS. 1a, 1b and 1c. The hinge 101 is connected between two elements of a deployable structure. Before deployment, the hinge 101 is held by a release mechanism in the folded configuration shown in FIG. 3a. The stops 124 engage together to prevent the hinge 101 from being folded back any further.

[0099] Upon deployment, the stored strain energy of the tape springs 116 actuates the hinge 101 through the partly unfurled configurations shown in FIG. 3b and then FIG. 3c until it reaches its fully extended configuration as shown in FIG. 3d. This unfurling of the tape springs 116 and the rotation of the hinge 101 thus acts to rotate the interlinked elements of the deployable structure (not shown, but which would be attached to the mounting members 106 of the hinge 101) relative to each other to help deploy the deployable structure.

[0100] When the tape springs 116 reach their fully extended configuration and the hinge 101 is opened fully, as shown in FIG. 3d, the stops 122 on the other side of the gears 108 come into contact to prevent the hinge 101 from opening beyond this position. As with the hinge 1 shown in FIGS. 1a, 1b and 1c, the tape springs 116 lock along their length when they have unfurled fully and the hinge 101 has been opened fully into the extended configuration shown in FIG. 3d, thus holding the hinge 101 in this configuration.

[0101] Again, as with the hinge 1 shown in FIGS. 1a, 1b and 1c, the retaining member 118 and the meshing of the gear teeth 110 in the hinge 101 shown in FIGS. 2a, 2b, 2c, 3a, 3b, 3c and 3d, as well as the locking of the tape springs 116, increases the out of plane stiffness of the hinge 101 during deployment and once it has been deployed, which thus increases the stiffness of the deployable structure of which it is a part.

[0102] It can be seen from the above that in at least preferred embodiments of the invention, a hinge for use in a deployable structure is provided that, owing to the provision of gears and a retaining member or plate, has an increased stiffness compared to conventional hinges, while also incorporating a tape spring as a low mass, reliable and simple actuation mechanism. This provides a particularly accurate and reliable hinge for use in deployable structures, e.g. for use in space.