A resonant damper

Abstract

The invention relates in preferred embodiments, to a resonant damper (1) preferably comprising a crank (2) arranged on a shaft (3) rotatable around a rotation axis (4), the crank has a radial guide (5) having a radial extension, a spring system (6) suspending a weight (7), Wherein the weight (7) and the radial guide (5) are mutually configured to confine movement of said weight (7) to a radial direction, and prevent the weight (7) to be positioned with its centre of mass coinciding with the rotation axis (4). The radial movement is a radial movement in a reference frame rotating around said rotation axis (4). The spring system (6) is configured to force the weight (7) towards a spring force equilibrium position (8) coinciding with or in vicinity of the rotation axis (4).

Description

[0001] A RESONANT DAMPER

[0002] FIELD OF THE INVENTION

[0003] The invention relates in preferred embodiments, to a resonant damper preferably comprising a crank arranged on a shaft rotatable around a rotation axis, the crank has a radial guide having a radial extension, a spring system suspending a weight, Wherein the weight and the radial guide are mutually configured to confine movement of said weight to a radial direction, and prevent the weight to be positioned with its centre of mass coinciding with the rotation axis. The radial movement is a radial movement in a reference frame rotating around said rotation axis. The spring system is configured to force the weight towards a spring force equilibrium position coinciding with or in vicinity of the rotation axis.

[0004] BACKGROUND OF THE INVENTION

[0005] In mechanical systems which involves rotation of a rotatable element e.g. a hinge rotating by a motorisation spring, it is often quite difficult to control the rotational speed of the rotatable element.

[0006] In space applications, such control of a rotational speed is often very critical in the sense that for instance various part of a satellite or space craft is to be deployed in a highly orchestrated sequence in order to allow deployment and prevent collision between various deployable parts. In addition, a predictable deployment allows for a minimisation in design margins such as component strength due to a reduction in the uncertainty of deployment speeds. This leads to direct benefits such as component mass and design flexibility which contribute to mission feasibility and performance.

[0007] In addition, such space application deployments most often rely on energy mechanically delivered by a motor, typically such as in a spring or spring like system and it is preferred than external intervention during deployment is not required, e.g. by active control system such as an electrical motor on the satellite that is autonomously controlled or controlled by ground based activation, since such intervention consumes energy, is unnecessarily complicated which affects reliability, and the electrical control system takes-up volume and weight. Passive control, alternatively, requires no external intervention or monitoring and is inherently simple as the control is a function of the design itself.

[0008] OBJECTS OF THE INVENTION

[0009] It is an object of the present invention to provide a device for controlling the rotational speed of a rotatable element.

[0010] It is a further object of the present invention to provide a device for passively controlling the rotational speed of a rotatable element.

[0011] It is a further object of the present invention to provide an alternative to the prior art.

[0012] SUMMARY OF THE INVENTION

[0013] Thus, the above described object and several other objects are intended to be obtained in a first aspect of the invention by providing a resonant damper preferably comprising

[0014] • a crank arranged on a shaft rotatable around a rotation axis, the crank has a radial guide having a radial extension ,

[0015] • a spring system suspending a weight,

[0016] wherein

[0017] • the weight and the radial guide are mutually configured to

[0018] o confine movement of said weight to a radial direction,

[0019] o and prevent the weight to be positioned with its centre of mass coinciding with the rotation axis,

[0020] wherein the radial movement is a radial movement in a reference frame rotating around said rotation axis;

[0021] • the spring system is configured to force the weight towards a spring force equilibrium position coinciding with or in vicinity of the rotation axis.

[0022] Terms used herein are used in a manner being ordinary to the skilled person. Some of the used terms are elucidated here below:

[0023] A resonant damper as defined herein and in particular in the accompanying claims may in accordance with preferred embodiments be described as a mechanical isotropic harmonic oscillator comprising of two degrees of freedom (LI, L2), support an orbiting weight with respect to a fixed base by spring system having isotropic and linear restoring force properties, and damping (D) allowing for dissipation of kinetic energy. In some embodiments, An XY planar spring configuration forms a primarily two-degree-of-freedom linkage between the weight and the spring system resulting in predominantly translational motion of the weight such that the weight travels in a, preferably, planar and circular orbit while keeping a fixed orientation.

[0024] Translational motion as used herein refers to motion of the weight in which all points of the weight have the same velocity. Accordingly, translational motion includes an orbital motion, where the vorticity (w = VxV) of the weight is essentially zero. Such a motion is depicted in Fig. 2C.

[0025] Radial refers to a direction being perpendicular to a rotational axis. Radial refers to the direction being either observed in a co-ordinate rotating around the rotational axis with the rotational speed of the radial guide, or a radial direction when the radial guide is non-rotating.

[0026] Non-coiled spring preferably refers to a spring not made-up from coiling a spring material. A non-coiled spring is typically designed to bend without substantial elongation or contraction. In preferred embodiments, the non-coiled spring may be or comprise a cantilever spring and / or a leaf spring.

[0027] In a second aspect the invention relates to a system for providing a constant rotational speed of an axle upon applying a torque to the axle, the system comprises

[0028] • a resonant damper, preferably according to the first aspect of the invention, • a transmission having a first rotational gear and an second rotational gear arranged in a meshed connection so that a rotation of one of the first or the second gear results in a rotation of another of the first or second gear, the axle being connected with the first gear, and the shaft rotatable connected with the second gear, the transmission being configured to convert a first rotational speed of the axle into a second rotational speed of the shaft, where the first and second rotational speeds being different from each other. In a third aspect, the invention relates to a deployable device comprising

[0029] • a system according, preferably according to the second aspect of the invention;

[0030] • a first and a second element (26) being connected to each other by a rotatable connection providing the first element to rotate at the rotatably connection relatively to the second element between deployed configuration and an nondeployed configuration,

[0031] • a coupling mechanically connecting the axle with the first element so that said rotation of the first element rotates the axle, and

[0032] • a motor, such as a rotating spring, an electrical motor, a pneumatic motor or a motor that provides torque, arranged to force the first element into the deployed configuration by the rotation of the first element.

[0033] BRIEF DESCRIPTION OF THE FIGURES

[0034] The present invention and in particular preferred embodiments thereof will now be described in more detail with regard to the accompanying figures. The figures show ways of implementing the present invention and are not to be construed as being limiting to other possible embodiments falling within the scope of the attached claim set.

[0035] Fig. 1 schematically illustrates in a 3-dimensional view a first embodiment of a resonant damper;

[0036] Fig. 2A is a photograph showing a second embodiment of a resonant damper. Kindly observe that the spring system is illustrated upside-down and detached from its position in the damper. Fig. 2B is a model used to describe functionality of preferred embodiments of a resonant damper; Fig. 3C schematically illustrates that the weight in preferred embodiments does not rotate, which may be described as the vorticity of the weight during its orbiting motion is zero, or essentially zero;

[0037] Fig. 3 schematically illustrates in a top view an embodiment of a spring system. The spring system is illustrated in combination with a weight and a frame; Fig. 4 schematically illustrates in a top view an embodiment of a crank; the crank is illustrated in combination with a weight and a frame;

[0038] Fig. 5 schematically illustrates in a top view another embodiment of a crank; the crank is illustrated in combination with a weight and a frame;

[0039] Fig. 6 schematically illustrates in a top view an embodiment of a spring system;

[0040] Fig. 7 schematically illustrates in a three-dimensional view an embodiment of a system for providing a constant rotational speed of an axle;

[0041] Fig. 8 schematically illustrates an embodiment of deployable device:

[0042] Fig. 9A schematically in 3-dimensional close-up view, the deployable device of Fig.

[0043] 8; the close-up view illustrates inter alia a system for providing a constant rotational speed of an axle, where system is connected so as to provide a constant rotational speed of one of the elements of the deployable device;

[0044] and

[0045] Fig. 9B is an exploded view of the close-up of Fig. 9A.

[0046] DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0047] Reference is made in particular to Fig. 1 schematically illustrating an embodiment of a resonant damper 1. As will become apparent from the following, the resonant damper is configured to provide a constant rotational speed of a shaft. Fig. 1 illustrated the weight 7 in a number of position during its orbiting around a rotational axis 4.

[0048] The illustrated resonant damper has a crank 2 which is arranged on a shaft 3 - in Fig. 1 the shaft 3 is left out in an attempt to render the drawing clear. The shaft 3 would be placed coaxially with the illustrated rotation axis 4. Hence, the shaft 3 is rotatable around the rotation axis 4. As will be detailed below, the shaft 3 can be said to be a rotational speed controlled shaft connected to the crank. In preferred embodiments, the crank provides torque to the mass which vibrate at a set frequency, which retards the rotation of the crank and causes the crank to rotate with the spring / mass resonance. Vibrate here refers to that the orbital path of the weight is a result of the natural frequency of two single degrees of freedom mass spring systems being added together whereby a 2ndmass spring system is 90 degrees out of phase with a 1stmass spring system, cf. Fig. 2B. It's the tendency of the system to want to vibrate at it's natural frequency (resonate) that is used in preferred embodiment of the resonant damper to the control speed of the shaft 3.

[0049] The crank 2 has a radial guide 5 having a radial extension. Radial here refers to a outward direction from the rotation axis 4. In the embodiment of Fig. 1, the radial guide 5 is illustrated as a box-shaped member, but may be given other shapes.

[0050] The resonant damper has spring system 6 suspending a weight 7. In the embodiment of Fig. 1, the spring system 6 comprises the spring 19 extending downwardly to a position at which the weight 7 is fixedly arranged. The weight in Fig. 1 is non-limiting illustrated as a sphere. As can be realized from Fig. 1, the weight 7 fits into the radial guide 5 in a manner allowing the weight to move in radial direction within radial guide 5.

[0051] The weight 7 and spring 11 system may typically function as a simple harmonic motion system with the frequency defined by the weight 7 and the spring 11 stiffness (the resonant damper) and it's damping ratio. Additionally, the amplitude of the harmonic motion may typically be a function of the base excitation and the resonant dampers damping ratio. When the harmonic motion of the LI and L2 degrees of freedom are 90degrees out of phase (Fig. 2B) and the spring stiffness in both degrees of freedom is the same, the resulting motion of the weight becomes circular (fig 2.C) with the period of the motion substantially equal to the period of oscillation in any one of the degrees of freedom. The phase shift between the LI and L2 is achieved by applying the base excitation with the same phase shift, which is simply carried out through the use of the rotating crank 2 with a radial guide 5.

[0052] Thus, as the rotational frequency is determined by simple harmonic motion of the resonant damper, torque applied to the shaft 3 results in an excitation force transferred through the crank 2 which increases the orbit radius of the mass within the confines of the radial guide 5. I.e. when more torque is applied through the shaft 3 and crank 2, the orbit radius increases (attempt to increase the speed of the system). When less torque is applied, the orbit radius decreases (attempt to decrease the speed of the system). As a result, the rotational speed of the weight 7 remain substantially constant due to the harmonic motion of the resonant damper.

[0053] Hence, the resonant damper can be characterized as being self adjusting, in the sense that weight and spring system has a rotation speed harmonic as defined by the physical properties of the resonant damper and independent of the torque applied to the shaft.

[0054] In order to assure excitement of the weight 7, the weight 7 and radial guide 5 is mutually configured to prevent the weight 7 from being positioned with its centre of mass coinciding with said rotation axis 4. Such a mutual configuration may be implemented by the radial guide 5 leaves no space for the weight at the rotation axis 4, so that the centre of mass of the weight 7 is located aways from the rotation axis 4 even when the radial guide 5 is not rotating.

[0055] The radial movement considered herein is typically a radial movement in a reference frame rotating around said rotation axis 4.

[0056] To allow for the spring force to act on the weight 7, when the weight 7 is in a position distanced from said rotation axis 4, the spring system 6 is configured to force the weight 7 towards a spring force equilibrium position 8. Such a spring force equilibrium position is typically coinciding with or in vicinity of the rotation axis 4. In the embodiment illustrated in Fig. 1, the spring 19 bends with increasing spring force when the weight 7 moves radially outward. In addition, work (force multiplied by distance) is done in the spring, and the work is dissipated by damping as heat. Hence, in preferred embodiments of a resonant damper, the weight 7 and the spring system 6 is configured to provide a circular, preferably planar, orbiting motion of the weight 7.

[0057] In preferred embodiments, the resonant damper may be described as a mechanical isotropic harmonic oscillator having at least two degrees of freedom. Such two degrees of freedom is disclosed in Fig. 2B with the indication of the degrees of freedom by LI and L2. The isotropic harmonic oscillator supports the weight 7 in an orbiting motion with respect to a fixed base by the spring system having isotropic and linear restoring force properties, and damping D allowing for the dissipation of kinetic energy.

[0058] In preferred embodiments, the spring system 6 is configured in an XY planar spring system 6, where XY here refers to a coordinate system having X and Y axes coinciding with e.g. the direction of two degrees of freedom directions LI, L2 indicated in Fig. 2B. The spring system 6 forms preferably a primarily two degree of freedom linkage between the weight 7 and the spring system 6 resulting in preferred embodiments in predominantly translational motion of the weight 7 in an orbiting motion while maintain the weight in a fixed orientation. Such an XY planar spring system is illustrated in Fig. 2A, and the predominantly translational motion of the weight is illustrated in Fig. 2C.

[0059] In the embodiment of Fig. 1, spring system 6 comprises a cantilever spring 19. This cantilever spring is connected at a first end 21 to the weight 7 and fixed at an opposite second end 22 to a fixing 20. The fixing 20 is an element which is maintained in a fixed position in the resonant damper and is arranged above the crank 2. By this, the cantilever spring 19 can bend into a convex shape to force the weight 7 towards the rotation axis 4 and towards the equilibrium position (8).

[0060] It is to be noted that the cantilever spring 19 does not need to be rotationally connected to the fixing 20.

[0061] The cantilever spring 19 may have a circular cross section and be made from spring steel. Such a cantilever leaf spring is illustrated in Fig. 1.

[0062] Reference is made to Fig. 2 showing a second embodiment of a resonant damper. Kindly observe that the resonant damper is illustrated partly disassembled state in the sense that the spring system 6 is displaced to the left relatively to its position when the resonant damper is in an assembled state. In the illustrated second embodiment, the spring system 6 comprising a frame 9 and a number of non-coiled springs 10 in the form of cantilever springs. The noncoiled springs 10 extends from the frame 9 in a plane, typically being a non-curve plane. Each of the non-coiled springs 10 extends from the frame 9 inwardly to and being connected with the weight 7. In the illustrated embodiments, each of the non-coiled springs 10 has one or more sections extending non-radially. The noncoiled springs 10 are in the illustrated embodiment, leaf springs. However, the invention is not limited to the use of leaf springs.

[0063] The non-radial extensions of the leaf springs provide, in preferred embodiments like the one of Fig. 2, a spring configuration having rotationally symmetry with respect to the spring stiffness is obtained. By rotationally symmetry is typically meant spring stiffness of the spring system 6 is essentially the same in essentially any radial direction. E.g. considering an x, y coordinate system with origo at the spring force equilibrium position 8, the spring stiffness in the x-direction is essentially the same as the spring stiffness in the y-direction.

[0064] Hence, in preferred embodiments, the spring system 6 is configured to provide a rotationally symmetry in spring stiffness of the spring system 6.

[0065] As perhaps most clearly seen in Fig. 3, the spring system may in preferred embodiment have springs which extent as illustrated. That is, the non-radially extending sections of the springs has a first leg 11a and a second leg lib forming an angle between the first leg 11a and the second leg lib. A first end of said first leg 11a is connected to the frame 9 and a second end of the first leg 11a is connected to a first end of the second leg lib. And, a second end of the second leg lib is connected to said weight 7. The connections between the spring and the frame and the weight 7 may be provided by gluing, welding or soldering, and the connections between the second end of the first leg 11a and the first end of the second leg lib may be provided by the material of the spring is bent, hence the first and the second legs are provided by bending a unitary body. The springs are typically made from spring steel.

[0066] In preferred embodiments, the angle between the first and the second legs 11a, lib is between 80 and 100 degrees, such as between 85 and 95 degrees. In preferred embodiments, the angle between the first and the second legs 11a, lib is substantially 90 degrees. An angle of 90 degrees may prove a spring having purely X directional spring, and a purely Y directional spring (see above for x and y co-ordinate system) wherein the combination of the two legs may result in rotational stiffness symmetry.

[0067] Reference is made to Fig. 6 schematically illustrating a spring system in which each of the non-coiled springs 10 extends curved from the frame 9 inwardly towards and being connected to the weight 7. The curved proceed for each of the springs 10 are essentially similar such as identical manner to with the purpose of providing rotational symmetry in the spring stiffness. As illustrated in Fig. 6 being a preferred embodiment,, the curved extend is a spiral extend.

[0068] A spring system 6, e.g. as shown in Figs. 2, 3 6, may comprise essentially any number of springs and the spring system is not limited to four spring 10.

[0069] Accordingly, the spring system may comprise one, two, three, four, five or six of the leaf springs 19.

[0070] While other types of springs than leaf springs may be used in the spring system, leaf springs may in general be a preferred spring type.

[0071] As perhaps most clearly seen in Fig. 2A, the weight 7 may comprises or be connected to a pivot 12. Such a pivot 12 is configured by its shaping to engage the radial guide 5 in a rotationally manner so as to guide the pivot 12 in a radial direction perpendicular to the rotational axis 4 while allowing the pivot 12 to rotate relatively to the radial guide 5. It is noted that configured by its shaping to engage also includes that the radial guide 5 and pivot 12 are mutually shaped to provide the guiding of the pivot 12 and allow for a rotation of the pivot 12. As otherwise disclosed herein, the radial direction is a radial direction in a reference frame rotating around the rotation axis 4.

[0072] Further, the pivot 12 and / or the weight 7 does in preferred embodiment not rotate but maintains its / their orientation as schematically illustrated in Fig. 2C. In preferred embodiments, the pivot 12 is configured to engage the radial guide 5 by being received at least partly in a linear slot 13 provided in the radial guide 5. This is inter alia disclosed in Fig. 2A. Kindly observe that in Fig. 2A, the spring system is illustrated upside-down to render the pivot 12 visible. As illustrated in Fig. 2A and in Figs. 4 and 5 linear slot 13 extends in the radial direction. The pivot may comprise a rotating element, such as a ball-bearing where an outer surface of the rotating element abuts an inner surface of the radial guide. Such a rotating element may reduce friction between pivot and the radial guide 5.

[0073] As illustrated in Fig. 2A and Fig. 4, the linear slot 13 may comprise two parallel guide walls 14 arranged with a distance, such a constant distance, between said two parallel guide walls 14. When the radial guide rotates in a direction, a reaction force is provided from the pivot contacting one of the guide wall 14. Hence, the pivot 12 does not have to fit snugly between the parallel guide wall 14, or in general within the radial guide 5. However, the pivot 12 has a receiving part 15 (see Fig 2A) dimensioned to be accommodated in between said two parallel guide walls 14.

[0074] As discussed in regards to Fig. 2C, the weight 7 has a constant orientation in regards to a fixed x-y coordinate system. To allow the weight 7 to maintains its constant orientation, at least the receiving part 15 of the pivot 12 is configured to be non-rotationally constrained relatively to the two parallel guide walls 14. To accomplish this, the receiving part 15 may be rotatable or the surface of receiving part abutting the guide wall 14 may be provided as a low friction surface, e.g. being polished. In a preferred embodiment, the receiving part may have a polygonal cross section, such as squared cross section, and at least the surface(s) abutting the guide wall 14 is a low friction surface such as being polished.

[0075] In preferred embodiments, the receiving part is cylindrical and may be rotatable around a centre axis.

[0076] Reference is made to Fig. 5 schematically illustrating preferred embodiment of a resonant damper 1. In the illustrated embodiment, the pivot 12 is configured to engage the radial guide 5 by the radial guide 5 comprises a radially extending beam 16 having an abutment surface 16 facing in a tangential direction relatively to the rotational axis for abutment of at least a section of said pivot (12). In the embodiment illustrated in Fig. 5, the reaction force of the pivot on the inner surface of the beam 16 only occurs when the crank 2 rotates in clockwise direction. Hence, the damper of Fig. 1 may be referred to a one-directional damper, whereas the embodiment of Fig. 4 may be referred to a bi-directional damper.

[0077] For a damper according to preferred embodiment, it is generally preferred that the engagement between the pivot 12 and the radial guide 5 is substantial frictionless. In preferred embodiments, such a substantial frictionless engagement is provided at least partly by the pivot 12 being rotationally around a center axis of said pivot 12.

[0078] As schematically illustrated in Fig. 2B, damping of the motion of the weight is present in the spring system. In many embodiments, damping is inherent in the spring(s), where work done by the spring dissipates into heat. However, the spring system may be equipped with dampers, such as the addition of materials with inherently high material damping capacity (the ability to dissipate elastic strain) in parallel with the springs, friction damping created by relative motion between spring elements, magnetic damping such as eddy currents or even viscous damping.

[0079] Reference is made to Fig. 7 schematically illustrating a system for providing a constant rotational speed of an axle 23 upon applying a torque to said axle 23. The constant rotational speed is provided a preferred embodiment of a resonant damper and a gear. The gear is used to alter the rotational speed of the axle 23 into a higher rotational speed for the resonant damper.

[0080] As illustrated, the system for providing a constant rotational speed comprises a preferred embodiment of resonant damper 1, a transmission 24 having a first rotational gear 24a and an second rotational gear 24b arranged in a meshed connection so that a rotation of one of the first or the second gear 24a, 24b results in a rotation of another of the first or second gear 24a, 24b. The axle 23 to be given a constant rotational speed is connected with the first gear 24a so that the first gear and the axle rotate in common. The shaft 3 of the resonant damper 1 is connected with the second gear 24b. Hence, the transmission 24 is configured to convert a first rotational speed of the axle 23 into a second rotational speed of said shaft 3, where the first and second rotational speeds are different from each other.

[0081] The inventors have realized that in some implementations of the system for providing constant rotational speed, a rotation of the axle 23 is to be kept low, such as <0.1 RPM. As an example, for deployment of a solar array in a space application, it is often desired that the deployment takes between 5-10 minutes. However, the operation of the damper may be increased with the rotational speed of the shaft 3. To accomplish this, the transmission 24 may be an overdrive gear. In preferred embodiment, A ratio between the first and the second rotational speed may between 100:1 and 50:1, such as between 90:1 and 60:1.

[0082] While Fig. 7 depicts the transmission as comprising a single first and a single second gear 24a, 24b, the first and / or second gear(s) may comprise of a gear system having a number of gear wheels.

[0083] Preferred embodiment of the invention is particular useful in space application to dampen the motion of a deployable device. An example on such deployable device is schematic illustrated in Fig. 8, where a two solar panels are illustrated in a deployed configuration. Fig. 9 illustrates the two solar panels in a non-deployed configuration in combination with elements providing deployment of the two solar panels.

[0084] For the solar panel and other deployable devices, the deployable device comprises an embodiment a system for providing a constant rotation speed a system according to the invention. The deployable device has a first and a second element 26 being connected to each other by a rotatably connection 25. With reference to Fig. 8, the elements 26 are the solar panels, and the rotatably connection is one or more hinges, as illustrated in Fig. 9. The rotatable connection provides the first element 26 to rotate at rotatably connection 25 relatively to the second element between deployed configuration and an non-deployed configuration.

[0085] The force for rotating the first and / or second element 26 relatively to each other may be provided by a constant toque spring as illustrated in Fig. 9A. However, other the force may be provided by other elements, such as an electrical or hydraulic motor.

[0086] In a preferred embodiment, a coupling is provided for mechanically connecting the axle 23 with the first element 26 so that the rotation of the first element 26 rotates axle 23. And, a rotating spring 27 is arranged to force the first element 26 into said deployed configuration by said rotation of said first element 26. In the preferred embodiment, the coupling comprises a reduction transmission which is placed between the constant torque spring having a reduction of 150:1. The reduction transmission is used to convert the relative high number of rotations of the constant torque spring into a rotation of around 180 degrees of the hinge.

[0087] In preferred embodiments, the deployed configuration is a folded configuration in which the two elements are arranged in a stacked configuration and the nondeployed configuration is an unfolded configuration in which said two elements are arranged side by side.

[0088] The two panels may be different from each other or of the same functional type, such as solar panels. In preferred embodiments , the two elements 26 each are solar panels, the two elements 26 each are part of a solar array, the two elements 26 each are part of an antenna, the two elements each are part of a deployable arm, or the two elements each are part of a door.

[0089] ITEMIZED LIST OF PREFERRED EMBODIMENTS

[0090] Item 1. A resonant damper (1) comprising

[0091] • a crank (2) arranged on a shaft (3) rotatable around a rotation axis (4), said crank (2) has a radial guide (5) having a radial extension ,

[0092] • a spring system (6) suspending a weight (7),

[0093] wherein

[0094] • said weight (7) and said radial guide (5) are mutually configured to

[0095] o confine movement of said weight (7) to a radial direction, o and prevent said weight (7) to be positioned with its centre of mass coinciding with said rotation axis (4),

[0096] wherein said radial movement is a radial movement in a reference frame rotating around said rotation axis (4);

[0097] • said spring system (6) is configured to force said weight (7) towards a spring force equilibrium position (8) coinciding with or in vicinity of said rotation axis (4).

[0098] Item 2. A resonant damper according to item 1, wherein said weight (7) and said spring system (6) is configured to provide a circular orbiting motion of said weight (7).

[0099] Item 3. A resonant damper according to item 1 or 2, wherein said damper is a mechanical isotropic harmonic oscillator having at least two degrees of freedom (LI, L2) and supporting said weight (7) in an orbiting motion with respect to a fixed base by said spring system having isotropic and linear restoring force properties, and damping (D) allowing for the dissipation of kinetic energy.

[0100] Item 4. A resonant damper according to any one of the preceding items, wherein said resonant damper system (6) is configured in an XY planar spring system (6) forming primarily two-degree-of-freedom linkage between said weight (7) and a frame (9) of said spring system (6) resulting in predominantly translational motion of said weight (7) in an orbiting motion while maintain said weight in a fixed orientation.

[0101] Item 5. A resonant damper (1) according to any one of the preceding items, wherein said spring system (6) comprises a cantilever spring (19) connected at a first end (21) to said weight (7) and fixed at an opposite second end (22) to a fixing (20) arranged above said crank (2) allowing said cantilever spring (19) bend into a convex shape to force said weight (7) towards said equilibrium position (8).

[0102] Item 6. A resonant damper (1) according to item 5, wherein said cantilever spring (19) is a cantilever leaf spring. Item 7. A resonant damper (1) according to any one of the preceding items, wherein said spring system (6) comprising a frame (9) and a number of noncoiled springs (10), said non-coiled springs (10) extends from said frame (9) in a plane, each of said non-coiled springs (10) extends from said frame (9) inwardly to and being connected with said weight (7), wherein each of said non-coiled springs (10) has one or more sections extending non-radially.

[0103] Item 8. A resonant damper (1) according to any one of the preceding items, wherein said spring system (6) is configured to provide a rotationally symmetry in spring stiffness of said spring system (6).

[0104] Item 9. A resonant damper (1) according to any one of the preceding items, when dependant on item 7, wherein said non-radially extending sections comprises a first leg (11a) and a second leg (lib) forming an angle between said first leg (11a) and said second leg (lib), wherein a first end of said first leg (11a) is connected to said frame (9) and a second end of said first leg (11a) is connected to a first end of said second leg (lib) and an second end of said second leg (lib) is connected to said weight (7).

[0105] Item 10. A resonant damper (1) according to item 9, where said angle between the first and the second legs (11a, lib) is between 80 and 100 degrees, such as between 85 and 95 degrees, preferably substantially 90 degrees.

[0106] Item 11. A resonant damper (1) according to any one of the preceding items 7-10, wherein each of said non-coiled springs (10) extends curved from said frame (9) inwardly towards said weight (7).

[0107] Item 12. A resonant damper (1) according to item 11, wherein said curved extend is a spiral extend.

[0108] Item 13. A resonant damper (1) according to any one of the preceding items 6-12, wherein said spring system (6) comprises one, two, three, four, five or six of said leaf springs (19). Item 14. A resonant damper (1) according to any one of the preceding items 6-13, wherein said non-coiled springs (10) are leaf springs.

[0109] Item 15. A resonant damper (1) according to any one of the preceding items, wherein said weight (7) comprises or is connected to a pivot (12) configured to engage said radial guide (5) in a rotationally manner so as to guide said pivot (12) in a radial direction perpendicular to said rotational axis (4) while allowing said pivot (12) to rotate, wherein said radial direction is a radial direction in a reference frame rotating around said rotation axis (4).

[0110] Item 16. A resonant damper (1) according to item 15, wherein said pivot (12) is configured to engage said radial guide (5) by being received at least partly in a linear slot (13) provided in said radial guide (5), wherein said linear slot (13) extends in said radial direction.

[0111] Item 17. A resonant damper (1) according to item 16, wherein said linear slot (13) comprises two parallel guide walls (14) arranged with a distance, such a constant distance, between said two parallel guide walls (14), and wherein said pivot (12) has a receiving part (15) dimensioned to be accommodated in between said two parallel guide walls (14).

[0112] Item 18. A resonant damper (1) according to item 17, wherein at least said receiving part (15) configured to be non-rotationally constrained relatively to said two parallel guide walls (14).

[0113] Item 19. A resonant damper (1) according to item 18, wherein said receiving part is cylindrical, and preferably being is rotatable around a centre axis.

[0114] Item 20. A resonant damper (1) according to any one of the preceding items 15-19, wherein said pivot (12) is configured to engage said radial guide (5) by said radial guide (5) comprises a radially extending beam (16) having an abutment surface (16) facing in a tangential direction relatively to said rotational axis for abutment of at least a section of said pivot (12). Item 21. A resonant damper (1) according to any one of the preceding items 15-20, wherein said engagement is substantial frictionless.

[0115] Item 22. A resonant damper (1) to item 21, wherein said substantial frictionless engagement is provided at least partly by said pivot (12) being rotationally around a center axis of said pivot (12).

[0116] Item 23. A system for providing a constant rotational speed of an axle (23) upon applying a torque to said axle (23), said system comprises

[0117] • a resonant damper (1) according to anyone of the preceding items,

[0118] • a transmission (24) having a first rotational gear (24a) and an second rotational gear (24b) arranged in a meshed connection so that a rotation of one of said first or said second gear (24a, 24b) results in a rotation of another of said first or second gear (24a, 24b), said axle (23) being connected with said first gear (24a), and said shaft (3) rotatable connected with said second gear (24b), said transmission (24) being configured to convert a first rotational speed of said axle (23) into a second rotational speed of said shaft (3), where said first and second rotational speeds being different from each other.

[0119] Item 24. A system according to item 23, wherein said transmission (24) is an overdrive transmission and the ratio between the first and the second rotational speed is between 100:1 and 50:1, such as between 90:1 and 60:1.

[0120] Item 25. A system according to item 23 or 24 wherein said first and / or said second gear comprises a gear system having a number of gear wheels.

[0121] Item 26. A deployable device comprising

[0122] • a system according to any one of the preceding items 23-25;

[0123] • a first and a second element (26) being connected to each other by a rotatably connection (25) providing said first element (26) to rotate at said rotatable connection (25) relatively to said second element between deployed configuration and an non-deployed configuration,

[0124] • a coupling mechanically connecting said axle (23) with said first element (26) so that said rotation of said first element (26) rotates said axle (23), and • a motor, such as a rotating spring (27), an electrical motor, a pneumatic motor or a motor that provide torque, arranged to force said first element (26) into said deployed configuration by said rotation of said first element (26).

[0125] Item 27. A deployable device according to item 26, wherein said rotatably connection (25) comprises one or more hinges.

[0126] Item 28. A deployable device according to item 26 or 27, wherein the deployed configuration is a folded configuration in which said two elements are arranged in a stacked configuration and the non-deployed configuration is an unfolded configuration in which said two elements are arranged side by side.

[0127] Item 29. A deployable device according to any one of the preceding items 26-28, wherein said two elements (26) each are solar panels.

[0128] Item 30. A deployable device according to any one of the preceding items 26-28, wherein said two elements (26) each are part of a solar array.

[0129] Item 31. A deployable device according to any one of the preceding items 26-28, wherein said two elements (26) each are part of an antenna.

[0130] Item 32. A deployable device according to any one of the preceding items 26-28, wherein said two elements each are part of a deployable arm.

[0131] Item 33. A deployable device according to any one of the preceding items 26-28, wherein said two elements each are part of a door.

[0132] Although the present invention has been described in connection with the specified embodiments, it should not be construed as being in any way limited to the presented examples. The scope of the present invention is set out by the accompanying claim set. In the context of the claims, the terms "comprising" or "comprises" do not exclude other possible elements or steps. Also, the mentioning of references such as "a" or "an" etc. should not be construed as excluding a plurality. The use of reference signs in the claims with respect to elements indicated in the figures shall also not be construed as limiting the scope of the invention. Furthermore, individual features mentioned in different claims, may possibly be advantageously combined, and the mentioning of these features in different claims does not exclude that a combination of features is not possible and advantageous. List of reference symbols used:

[0133] 1 Resonant damper

[0134] 2 Crank

[0135] 3 Shaft

[0136] 4 Rotation axis

[0137] 5 Radial guide

[0138] 6 Spring system

[0139] 7 Weight

[0140] 8 Spring force equilibrium position

[0141] 9 Frame

[0142] 10 Non-coiled springs

[0143] 11a First leg

[0144] lib Second leg

[0145] 12 Pivot

[0146] 13 Linear slot

[0147] 14 Guide wall

[0148] 15 Receiving part

[0149] 16 Beam

[0150] 17 Abutment surface

[0151] 18 Hub

[0152] 19 Cantilever spring

[0153] 20 Fixing

[0154] 21 First end

[0155] 22 Second end

[0156] 23 Rotatable axle

[0157] 24 Transmission

[0158] 24a First gear

[0159] 24b Second gear

[0160] 25 Rotatably connection

[0161] 26 Elements

[0162] 27 Rotating spring, such as a constant torque spring 29 Reduction transmission

[0163] 30 Hinge

[0164] 31 Mounting bracket

[0165] 32 Resonant damper bracket

Claims

CLAIMS1. A resonant damper (1) comprising• a crank (2) arranged on a shaft (3) rotatable around a rotation axis (4), said crank (2) has a radial guide (5) having a radial extension ,• a spring system (6) suspending a weight (7),wherein• said weight (7) and said radial guide (5) are mutually configured too confine movement of said weight (7) to a radial direction,o and prevent said weight (7) to be positioned with its centre of mass coinciding with said rotation axis (4),wherein said radial movement is a radial movement in a reference frame rotating around said rotation axis (4);• said spring system (6) is configured to force said weight (7) towards a spring force equilibrium position (8) coinciding with or in vicinity of said rotation axis (4).

2. A resonant damper according to claim 1, wherein said weight (7) and said spring system (6) is configured to provide a circular orbiting motion of said weight (7).

3. A resonant damper according to claim 1 or 2, wherein said damper is a mechanical isotropic harmonic oscillator having at least two degrees of freedom (LI, L2) and supporting said weight (7) in an orbiting motion with respect to a fixed base by said spring system having isotropic and linear restoring force properties, and damping (D) allowing for the dissipation of kinetic energy.

4. A resonant damper according to any one of the preceding claims, wherein said resonant damper system (6) is configured in an XY planar spring system (6) forming primarily two-degree-of-freedom linkage between said weight (7) and a frame (9) of said spring system (6) resulting in predominantly translational motion of said weight (7) in an orbiting motion while maintain said weight in a fixed orientation.

5. A resonant damper (1) according to any one of the preceding claims, wherein said spring system (6) comprises a cantilever spring (19) connected at a first end (21) to said weight (7) and fixed at an opposite second end (22) to a fixing (20) arranged above said crank (2) allowing said cantilever spring (19) bend into a convex shape to force said weight (7) towards said equilibrium position (8).

6. A resonant damper (1) according to claim 5, wherein said cantilever spring (19) is a cantilever leaf spring.

7. A resonant damper (1) according to any one of the preceding claims, wherein said spring system (6) comprising a frame (9) and a number of non-coiled springs (10), said non-coiled springs (10) extends from said frame (9) in a plane, each of said non-coiled springs (10) extends from said frame (9) inwardly to and being connected with said weight (7), wherein each of said non-coiled springs (10) has one or more sections extending non-radially.

8. A resonant damper (1) according to any one of the preceding claims, wherein said spring system (6) is configured to provide a rotationally symmetry in spring stiffness of said spring system (6).

9. A resonant damper (1) according to any one of the preceding claims, when dependant on claim 7, wherein said non-radially extending sections comprises a first leg (11a) and a second leg (lib) forming an angle between said first leg (11a) and said second leg (lib), wherein a first end of said first leg (11a) is connected to said frame (9) and a second end of said first leg (11a) is connected to a first end of said second leg (lib) and an second end of said second leg (lib) is connected to said weight (7).

10. A resonant damper (1) according to claim 9, where said angle between the first and the second legs (11a, lib) is between 80 and 100 degrees, such as between 85 and 95 degrees, preferably substantially 90 degrees.

11. A resonant damper (1) according to any one of the preceding claims 7-10, wherein each of said non-coiled springs (10) extends curved from said frame (9) inwardly towards said weight (7).

12. A resonant damper (1) according to claim 11, wherein said curved extend is a spiral extend.

13. A resonant damper (1) according to any one of the preceding claims 6-12, wherein said spring system (6) comprises one, two, three, four, five or six of said leaf springs (19).

14. A resonant damper (1) according to any one of the preceding claims 6-13, wherein said non-coiled springs (10) are leaf springs.

15. A resonant damper (1) according to any one of the preceding claims, wherein said weight (7) comprises or is connected to a pivot (12) configured to engage said radial guide (5) in a rotationally manner so as to guide said pivot (12) in a radial direction perpendicular to said rotational axis (4) while allowing said pivot (12) to rotate, wherein said radial direction is a radial direction in a reference frame rotating around said rotation axis (4).

16. A resonant damper (1) according to claim 15, wherein said pivot (12) is configured to engage said radial guide (5) by being received at least partly in a linear slot (13) provided in said radial guide (5), wherein said linear slot (13) extends in said radial direction.

17. A resonant damper (1) according to claim 16, wherein said linear slot (13) comprises two parallel guide walls (14) arranged with a distance, such a constant distance, between said two parallel guide walls (14), and wherein said pivot (12) has a receiving part (15) dimensioned to be accommodated in between said two parallel guide walls (14).

18. A resonant damper (1) according to claim 17, wherein at least said receiving part (15) configured to be non-rotationally constrained relatively to said two parallel guide walls (14).

19. A resonant damper (1) according to claim 18, wherein said receiving part is cylindrical, and preferably being is rotatable around a centre axis.

20. A resonant damper (1) according to any one of preceding claims 15-19, wherein said pivot (12) is configured to engage said radial guide (5) by said radial guide (5) comprises a radially extending beam (16) having an abutment surface (16) facing in a tangential direction relatively to said rotational axis for abutment of at least a section of said pivot (12).

21. A resonant damper (1) according to any one of the preceding claims 15-20, wherein said engagement is substantial frictionless.

22. A resonant damper (1) according to claim 21, wherein said substantial frictionless engagement is provided at least partly by said pivot (12) being rotationally around a center axis of said pivot (12).

23. A system for providing a constant rotational speed of an axle (23) upon applying a torque to said axle (23), said system comprises• a resonant damper (1) according to anyone of the preceding claims,• a transmission (24) having a first rotational gear (24a) and an second rotational gear (24b) arranged in a meshed connection so that a rotation of one of said first or said second gear (24a, 24b) results in a rotation of another of said first or second gear (24a, 24b), said axle (23) being connected with said first gear (24a), and said shaft (3) rotatable connected with said second gear (24b), said transmission (24) being configured to convert a first rotational speed of said axle (23) into a second rotational speed of said shaft (3), where said first and second rotational speeds being different from each other.

24. A system according to claim 23, wherein said transmission (24) is an overdrive transmission and the ratio between the first and the second rotational speed is between 100:1 and 50:1, such as between 90:1 and 60:1.

25. A system according to claim 23 or 24 wherein said first and / or said second gear comprises a gear system having a number of gear wheels.

26. A deployable device comprising• a system according to any one of the preceding claims 23-25;• a first and a second element (26) being connected to each other by a rotatably connection (25) providing said first element (26) to rotate at said rotatable connection (25) relatively to said second element between deployed configuration and a non-deployed configuration,• a coupling mechanically connecting said axle (23) with said first element (26) so that said rotation of said first element (26) rotates said axle (23), and• a motor, such as a rotating spring (27), an electrical motor, a pneumatic motor or a motor that provide torque, arranged to force said first element (26) into said deployed configuration by said rotation of said first element (26).

27. A deployable device according to claim 26, wherein said rotatably connection (25) comprises one or more hinges.

28. A deployable device according to claim 26 or 27, wherein the deployed configuration is a folded configuration in which said two elements are arranged in a stacked configuration and the non-deployed configuration is an unfolded configuration in which said two elements are arranged side by side.

29. A deployable device according to any one of the preceding claims 26-28, wherein said two elements (26) each are solar panels.

30. A deployable device according to any one of the preceding claims 26-28, wherein said two elements (26) each are part of a solar array.

31. A deployable device according to any one of the preceding claims 26-28, wherein said two elements (26) each are part of an antenna.

32. A deployable device according to any one of the preceding claims 26-28, wherein said two elements each are part of a deployable arm.

33. A deployable device according to any one of the preceding claims 26-28, wherein said two elements each are part of a door.

Images