locking device

Abstract

A locking device (1) for releasably locking components in or on a vehicle, in particular a spacecraft, comprising a housing (2) which is or can be provided with first fastening means (20) and has a receiving opening (22), a coupling bolt (3) which is or can be provided with second fastening means (30) and which is designed to be at least partially inserted into the receiving opening (22) and locked there, a retaining shell (4) arranged in the housing (2) and which at least partially encompasses an engagement section (32) of the coupling bolt (3) in a state inserted into the receiving opening (22), the retaining shell (4) consisting of at least two ring-segment-shaped circumferential section elements (40, 42), and at least one locking means (5) designed to releasably lock the retaining shell (4) in this state, is characterized in that the locking means (5) has an axially movable clamping ring (50).which is designed to assume a locking position in a first axial position, in which the clamping ring (50) at least partially engages the circumferential section elements (40, 42) along their circumference, and to assume a release position in a second axial position, in which the clamping ring (50) releases the circumferential section elements (40, 42) for radial movement,

Description

[0001] The present invention relates to a locking device according to the preamble of claim 1. In particular, it relates to a preferably force-amplifying mechanical hold-down-and-release (HDRM) mechanism. It further relates to a vehicle, in particular a spacecraft, with at least one such locking device.

[0002] Hold-down-and-release mechanisms (HDRMs), also known as launch locks, are releasable locking devices used to secure moving components in moving systems, particularly in space systems. These components must be protected from strong vibrations during launch and reliably released after deployment into a predetermined orbit.

[0003] Various devices are available on the market for this purpose. One subgroup of high-pressure residual current devices (HDRMs) are so-called "release nuts," in which a shouldered bolt is held in place by two halves. The bolt has a threaded end for fastening, into or onto which the component to be secured can be screwed. A retaining wire wrapped around the two halves prevents them from sliding apart under load. This retaining wire is connected at its ends to a thinner wire that holds the retaining wire in position and can be melted with high electrical currents. If the thinner wire melts, the retaining wire is severed and loses its function of holding the halves together. If the retaining wire unwinds, the halves are loosened, and the bolt is released.These types of release nuts can withstand high forces, are tolerant of slight tilting of the force acting on the bolt, and allow the bolt considerable play after release. However, multiple releases are not possible with these locking devices, as the thin wire must be melted for release. If such locking devices are to be tested for reliability, the locking mechanism must be triggered several times, requiring the entire retaining wire to be replaced each time. This results in very high costs.

[0004] Another type of releasable locking device uses a fracture bolt that breaks to release the locking mechanism. While fracture bolt-based locking devices can withstand high axial forces, they are very susceptible to lateral forces. After release, the bolt is free to move and its movement is unrestricted. However, a major disadvantage of this type of locking device is the shock generated when the bolt breaks, which triggers a force impulse. These releasable locking devices are also not resettable.

[0005] DE 10 2021 103 203 B3 discloses and describes an actuator consisting of two coaxially arranged discs, each equipped with hooks on its outer circumference. A wire made of a shape-memory alloy is tensioned around these hooks in such a way that it holds the two discs together against the axial force of a compression spring. When the wire heats up, it shortens, and the two discs are pulled against each other. This tensile force is used to open a collet and release a bolt.

[0006] From DE 10 2020 107 936 A1, an HDRM device is known in which a smooth bolt is held by friction using a collet. Release is achieved not by a wire, but by rods made of shape memory material.

[0007] One disadvantage of these known mechanisms is that the bolt being released cannot withstand high forces, as it is held in the collet only by friction. Furthermore, the force applied to the bolt must be precisely axial, since even slight tilting could damage the device or cause the bolt to jam and prevent release. After release, the bolt remains tightly guided axially with little play. Therefore, it can easily jam.

[0008] German patent application DE 10 2020 119 048 A1 discloses and describes a device designed to hold and release a wheel using a conventional high-pressure retraction mechanism (HPM) positioned centrally to the wheel. After the HPM is triggered, auxiliary holding devices on the wheel's circumference are released. This mechanism is not designed for force amplification and secures the wheel with relatively small forces. The force flow is relatively complex and cannot be easily transferred to other applications. Furthermore, a slightly oblique load on the wheel can cause the retraction mechanism to jam in the wheel hub.

[0009] The object of the present invention is to provide an improved locking device of the type of a "release nut" which has a higher tolerance and yet releases reliably.

[0010] This problem is solved by a locking device having the features of claim 1.

[0011] A locking device for the releasable locking of components in or on a vehicle, in particular a spacecraft, comprising a housing which is or can be provided with first fastening means and has a receiving opening, a coupling bolt which is or can be provided with second fastening means and which is designed to be at least partially inserted into the receiving opening and locked there, a retaining shell arranged in the housing and which at least partially encompasses an engagement section of the coupling bolt in a state inserted into the receiving opening, the retaining shell consisting of at least two ring-segment-shaped circumferential section elements, and at least one locking means designed to releasably lock the retaining shell in this state, is characterized in that the locking means has an axially movable clamping ring which is designed toto assume a locking position in a first axial position, in which the clamping ring at least partially engages the circumferential section elements along their circumference, and to assume a release position in a second axial position, in which the clamping ring releases the circumferential section elements for radial movement. The mechanism of the locking device according to the invention can be reset very easily and cost-effectively after release, since no parts are destroyed during release.

[0012] Further preferred and advantageous design features of the locking device according to the invention are the subject of dependent claims 2 to 10.

[0013] Preferably, the housing is designed as a cylinder with a cylinder shell wall surrounding a cylinder bore and a cylinder base formed by a cylinder end wall, in which the receiving opening is provided as a preferably central through-bore. This through-bore, whose bore axis preferably runs coaxially to the cylinder axis, can have a significantly larger diameter than the largest outer diameter of the coupling bolt so that the bolt does not jam in the through-bore even if the bolt axis is inclined relative to the cylinder axis, for example by up to 5°, preferably up to 10°.

[0014] In a cylindrical housing design, it is advantageous if the clamping ring has a cylindrical outer circumferential surface whose radius is slightly smaller than the radius of the inner circumferential surface of the cylinder bore, so that the clamping ring can be guided and moved along the inner circumferential surface of the cylinder bore with its outer circumferential surface in the direction of the cylinder axis. In this way, the clamping ring is supported in the housing by sliding bearings.

[0015] Preferably, the clamping ring has a conical inner circumferential surface that defines an axial clamping ring opening. This opening tapers from a first end face of the clamping ring facing the cylinder base to a second end face facing away from the cylinder base at a first conical angle inclined to the cylinder axis. This allows the clamping ring, in its locking position near the piston base, to press the circumferential section elements against each other and against the coupling bolt, clamping and thus locking the bolt.

[0016] It is further advantageous if the ring-segment-shaped circumferential section elements of the retaining shell each have a conical outer circumferential wall, the radius of which decreases at a second cone angle inclined to the cylinder axis from a first end face of the retaining shell facing the cylinder base to a second end face of the retaining shell facing away from the cylinder base. Particularly preferably, the second cone angle of the respective conical outer circumferential wall of the ring-segment-shaped circumferential section elements corresponds to the first cone angle of the conical inner circumferential surface of the clamping ring. This common cone angle depends on the material pairing used; for steel / steel, the cone angle is preferably in the range of 20° to 40°, more preferably between 25° and 30°.

[0017] In an advantageous embodiment of the invention, which can be combined with other embodiments, the coupling bolt has a predominantly cylindrical outer circumference, which is provided with a constricted section of smaller diameter forming the engagement section of the coupling bolt. This constricted section is arranged axially along the coupling bolt between a first cylindrical section and a second cylindrical section, each of larger diameter. At least a portion of the ring-segment-shaped circumferential section elements forming the retaining shell has a radially inwardly directed inner circumferential section, which is designed to engage in the constricted section in the locking position. In this way, a reliable positive connection between the circumferential section elements and the coupling bolt is created in the locking position.

[0018] It is advantageous if the constricted section transitions into the second cylinder section at its end furthest from the cylinder base by forming a linear-conical or convex-conical annular step, with the radially outer edge of the annular step being axially farther from the end face of the coupling bolt protruding from the receiving opening than the radially inner edge of the annular step. Providing a convex-conical annular step allows the axis of the coupling bolt to tilt relative to the cylinder axis, thereby improving the fit tolerance of the locking device for assembly.

[0019] It is further advantageous if the ring-segment-shaped circumferential section elements of the retaining shell each have a radially inwardly inclined rear ring-step section towards the cylinder end wall, which is designed, at least in a central circumferential region, to abut the ring step of the constriction section of the coupling bolt. The angle of inclination of the rear ring-step section inclined towards the cylinder end wall depends on the material pairing. In the case of steel / steel, this angle of inclination is preferably in a range between 10° and 30°, more preferably in a range between 20° and 30°.

[0020] It is particularly advantageous if the rear ring step section of the respective ring segment-shaped circumferential section element of the retaining shell is provided with a respective relief groove on its free inner circumferential areas, which in the release position allows easier sliding or even free passage of the coupling bolt and thereby first facilitates pushing the ring segment-shaped circumferential section elements apart radially outwards and then facilitates the release of the coupling bolt in the axial direction.

[0021] The individual ring-segment-shaped circumferential sections of the retaining shell can have relief grooves that allow the coupling bolt to slide more quickly. This allows the coupling bolt to slide on the respective ring-segment-shaped circumferential sections of the retaining shell, but it is less stabilized due to the smaller sliding surface area of ​​the circumferential sections relative to the housing. The retaining shells of conventional HDRMs do not have relief grooves, but instead have a wedge opening of approximately 100°.

[0022] In a further advantageous embodiment of the invention, which can be combined with other embodiments, at least one locking element extending through one wall of the housing, preferably the cylinder jacket, is provided. This locking element is designed to engage with the locking means in the locked position and to be disengaged to achieve the release position. A mechanism designed in this way in a locking device according to the invention can be released by manually or by motorized pulling of a locking bolt or a clamp. The retaining clamp secures the clamping ring on two sides and preferably has the same diameter at its free ends as the clamping ring at its engaging ends. This prevents small parts of the retaining clamp from shearing off when it is pulled out.

[0023] The clamping ring can be actively pulled or pushed out of the housing by pressure pieces or springs to achieve release.

[0024] The tensile force on the coupling bolt is reduced by several inclined planes formed by the conically shaped surfaces, allowing the coupling bolt to be released with significantly less force. The angles of inclination, or cone angles, are preferably less than 45° relative to the cylinder axis, thus reducing the forces. The lower limit is the self-locking of the material pairing with the corresponding coefficient of friction; otherwise, the interacting elements would jam and could no longer be separated.

[0025] Preferred embodiments of the invention with additional design details and further advantages are described and explained in more detail below with reference to the accompanying drawings.

[0026] It shows: Fig. 1 a longitudinal section through a locking device according to the invention in the locked position and Fig. 2 the locking device Fig. 1 in the release position.

[0027] An exemplary embodiment of a locking unit 1 according to the invention is shown in Fig. 1 and Fig. 2 shown in vertical section. Fig. Figure 1 shows a locking position in which a coupling bolt 3 is locked in a housing 2 of the locking device 1, and Fig. Figure 2 shows a release position in which the coupling bolt can move out of the housing 2 of the locking device 1.

[0028] The housing 2 is designed as a cylinder with a cylinder shell wall 24 that surrounds a cylinder bore 25 and is provided at one axial end with a cylinder base 23 formed by a cylinder end wall 21. A through-bore is provided in the cylinder end wall 21, coaxial to the cylinder axis X, forming a receiving opening 22 through which the coupling bolt 3 can be inserted into the housing 2.

[0029] The housing 2 is provided with first fastening means 20, which in the example shown are formed by threaded holes and through which the housing can be attached to a vehicle structure, for example, the structure of a spacecraft, by means of screws. A further threaded hole is provided as a second fastening means 30 in the free end face 31 of the coupling bolt 3, which projects from the housing 2. By means of this second fastening means 30, for example, a vehicle or payload component can be connected to the coupling bolt 3, for example, by screwing it in place. If the coupling bolt 3 is then received in the housing 2 of the locking device 1 and the locking device is in the locked position, the component is firmly connected to the vehicle structure. In the release position, the component can detach from this fixed connection.

[0030] The coupling bolt 3 has a predominantly cylindrical outer circumference 33, which is provided with a constriction section 34 of smaller diameter. This constriction section 34 is located axially between a first cylindrical section 35 and a second cylindrical section 36, each of larger diameter. This constriction section 34 forms an engagement section 32 of the coupling bolt 3. At its end furthest from the cylinder base 23, the constriction section 34 transitions into the second cylindrical section 36 by forming a linear-conical or convex-conical annular step 37. The radially outer edge 37' of the annular step 37 is located further axially from the end face 31 of the coupling bolt 3 projecting from the receiving opening 22 than the radially inner edge 37" of the annular step 37.

[0031] In the cylinder bore 25 of the housing 2, a retaining shell 4, consisting in the example shown of two ring-segment-shaped circumferential section elements 40, 42, is arranged near the cylinder end wall 21. The ring-segment-shaped circumferential section elements 40, 42 of the retaining shell 4 each have a conical outer circumferential wall 41, 43, the radius of which decreases at a cone angle β inclined to the cylinder axis X from a first end face 44 of the retaining shell 4 facing the cylinder base 23 to a second end face 45 of the retaining shell 4 facing away from the cylinder base 23. On their radially inner side, the circumferential section elements 40, 42 are each provided with a radially inwardly directed inner circumferential section 46, 47, which is designed to engage in the constricted section 34 of the coupling bolt 3 in the locking position.In this way, the inner circumferential sections 46, 47 of the circumferential section elements 40, 42 of the retaining shell 4 at least partially engage the coupling bolt 3 in its engagement section 32 and assume a locking position. They thus block any axial movement of the coupling bolt 3, which is in a state inserted into the receiving opening 22, directed out of the housing 2.

[0032] The circumferential section elements 40, 42 of the retaining shell 4 are surrounded by an annular locking element 5 in the locked position of the locking device 1 and are thereby held in their respective locked positions. The locking element 5 has an axially movable clamping ring 50, which is provided with a cylindrical outer circumferential surface 51, the radius R1 of which is slightly smaller than the radius R2 of the inner circumferential surface 26 of the cylinder bore 25. This allows the clamping ring 50 to slide along the inner circumferential surface 26 of the cylinder bore 25 with its outer circumferential surface 51 and thus be movable in the direction of the cylinder axis X.

[0033] The clamping ring 50 has a conical inner circumferential surface 53, which defines an axial clamping ring opening 54. This opening tapers from a first end face 55 of the clamping ring 50 facing the cylinder base 23 to a second end face 56 of the clamping ring 50 facing away from the cylinder base 23 at a first angle α inclined to the cylinder axis X. This angle α corresponds essentially to the angle β of the respective conical outer circumferential walls 41, 43 of the circumferential section elements 40, 42 of the retaining shell 4, so that the conical outer circumferential walls 41, 43 bear against the conical inner circumferential surface 53 of the clamping ring 50 in the locking position, as shown in Fig. 1 is shown.

[0034] The ring-segment-shaped circumferential section elements 42, 43 of the retaining shell 4 each have, in the region of their end face facing away from the cylinder end wall 21, a rear annular step section 48, 49 inclined radially inwards and towards the cylinder end wall 21, which, in the locking position of the retaining shell 4, bears against the annular step 37 of the constriction section 34 of the coupling bolt 3 in at least a central circumferential region. This allows the coupling bolt 3, when the circumferential section elements 42, 43 of the retaining shell 4 move radially outwards into the release position, to move outwards along the annular step sections 48, 49 outwards from the housing 2, thereby pushing the circumferential section elements 42, 43 further radially outwards.

[0035] Furthermore, the rear ring-shaped step section 48, 49 of the respective ring-segment-shaped circumferential section element 40, 42 of the retaining shell 4 is provided on its free inner circumferential areas, i.e., radially inwards, with a respective relief groove that forms a ramp extending in the opening direction of the circumferential section element 40, 42 and on which the coupling bolt 3 can slide during a radially outward movement of the respective circumferential section element 40, 42. In the release position, the relief groove allows the coupling bolt to slide more easily and quickly along the respective ring-segment-shaped circumferential section element 40, 42 or even to pass through it abruptly. This initially causes the ring-segment-shaped circumferential section elements 40, 42 to be pushed apart radially outwards and then accelerates the complete release of the coupling bolt 3 in the axial direction.

[0036] The locking device according to the invention thus takes place in the Fig. In the first axial position shown in Figure 1, the coupling bolt 3 enters a locking position in which the clamping ring 50 at least partially engages the circumferential section elements 40, 42 along their circumference. The locking element 5, i.e., the clamping ring 50, is held in its position by a locking element 6. In the example shown, the locking element 6 is formed by a retaining clip 60, which extends through the wall 27 of the housing 2 and bears against the edge regions of the second end face 56 of the clamping ring 50, thus fixing it axially. For this purpose, slots 28, 28' are formed in the cylindrical shell 24, into which the retaining clip 60 is inserted. The retaining clip 60, which is, for example, U-shaped, preferably has radii on the inside of its free legs engaging in the housing 2, which are adapted to the outer circumference of the clamping ring 50. This allows for line contact with the clamping ring.At its free ends, the retaining clip 60 is chamfered on the inside of its respective free end in a plane parallel to the cylinder axis X, or it has a radius around the cylinder axis X that corresponds to the radius of the outer circumference of the clamping ring 50. This prevents an inner corner of the respective free end of the retaining clip 60 from being sheared off by the force of the axially displacing clamping ring 50 when the retaining clip 60 is pulled out of the slots 28, 28', thus reducing the risk of the formation of uncontrolled space debris.

[0037] The retaining clip 60 also has the advantage that the clamping ring 50 is held on two opposite sides and does not jam. Alternatively, at least one bore 29 can be provided in the wall 27 of the housing, into which a locking bolt (not shown) is inserted, which bears against the second end face 56 of the clamping ring 50 and fixes it in the axial direction.

[0038] If the retaining clip 60 or at least one locking bolt is pulled out of the associated opening 28, 28', 29 in the wall 27 – either manually or mechanically – the clamping ring 50 is released and can move along the cylinder axis X into the second axial position and assume a release position in which the clamping ring 50 releases the circumferential section elements 40, 42 for radial movement.

[0039] The arrangement and inclination of the inclined sliding surfaces of the locking device according to the invention, which form inclined planes, cause transverse and axial forces when a tensile force directed outwards from the housing 2 is exerted on the coupling bolt. When the locking ring 50 is released, these forces cause an axial movement of the clamping ring 50 into the Fig. The release position shown in Figure 2 is achieved by the conical ring step sections 48, 49 of the ring-segment-shaped circumferential section elements 40, 42, which interact with the conical or convex ring step 37 of the coupling bolt 3. These conical ring step sections convert an outwardly directed axial tensile force on the coupling bolt into radially outwardly directed transverse forces that act on the ring-segment-shaped circumferential section elements 40, 42. These transverse forces act via their conical outer circumferential walls 41, 43 on the conical inner circumferential surface 53 of the clamping ring 50 and generate an axial force component acting on the clamping ring 50, which is directed in its release position. The axial movement of the clamping ring 50 from the locking position to the release position can, for example, be additionally supported by pressure pieces 57, which are provided distributed around the circumference in the cylinder base 23.The pressure pieces 57 each have a mechanical energy storage device, preferably a compression spring, pre-tensioned in an axial direction parallel to the cylinder axis X. Each pressure piece 57 is located in the Fig.In the locking position shown in Figure 1, the clamping ring 50 is compressed and thus exerts a spring force in the axial direction on each of the protrusions 58 located on a pressure piece 57. These protrusions 58 are formed on the first annular end face 55 of the clamping ring 50, which faces the cylinder base 23, and engage in recesses in the cylinder base 23, in each of which a pressure piece 57 is provided. The pressure pieces 57 thus exert a total axial force on the clamping ring 50 in the direction of the release position. In this way, small tensile forces acting on the locking element 6, for example on the retaining clip 60, can release the locking element 6, while larger forces can be released to displace the clamping ring 50. Then, tensile forces acting on the coupling bolt 3 push the ring-segment-shaped circumferential section elements 40, 42 radially outwards, thereby releasing the coupling bolt 3.

[0040] If the ring step 37 of the coupling bolt 3 is convex, i.e., it forms a convex spherical contact surface with the conical ring step sections 48, 49 of the ring segment-shaped circumferential section elements 40, 42, the coupling bolt 3 can align itself ideally with the direction of tension. This significantly reduces bending moments in the coupling bolt 3.

[0041] This force transmission allows the locking device 1 according to the invention to be significantly smaller than HDRM devices of the prior art. Furthermore, the locking device according to the invention can easily be triggered multiple times.

[0042] Reference numerals in the claims, description and drawings serve only to improve understanding of the invention and are not intended to limit the scope of protection. Reference symbol list

[0043] It refers to: 1 locking device 2 cases 3 coupling bolts 4 holding trays 5 locking devices 6 Locking element 20 first fastening device 21 Cylinder end wall 22 Intake opening 23 Cylinder base 24 cylinder shell wall 25 cylinder bore 26 Inner circumferential surface of the cylinder bore 25 27 Housing wall 2 28 slots 28' slot 29 bore 30 second fastener 31 Free end face of the coupling bolt 32 Engagement section of the coupling bolt 3 33 Outer circumference of the coupling bolt 3 34 Constriction section 35 first cylinder section 36 second cylinder section 37 ring stage 37' radial outer edge of the ring step 37 37" radial inner edge of the ring step 37 40 ring-segment-shaped circumferential section element 41 conical outer perimeter wall 42 ring-segment-shaped circumferential section element 43 conical outer perimeter wall 44 first end face of the holding shell 45 second end face of the holding tray 46 radially inward-facing inner circumferential section 47 radially inwardly directed inner circumferential section 48 rear ring step section 49 rear ring step section 50 axially movable clamping ring 51 cylindrical outer circumferential surface 53 conical inner circumferential surface 54 axial clamping ring opening 55 first front 56 second front 57 printed pieces 58 surveys 60 retaining clips R1 Radius of the outer circumferential surface R2 radius of the inner circumferential surface X cylinder axis α angle β Cone angle

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