Emission Unit

Abstract

The release unit for a satellite comprises a housing closed by a door and in which a guide for the satellite is provided, the guide comprising an angled rail and a fastening device for fixedly fastening the satellite by means of a fastening mechanism.

Description

[Technical field]

[0001] The invention relates to an ejection unit for at least one cuboid satellite, in particular at least one picosatellite, comprising a housing closed by at least one door and provided with a guide for accommodating the satellite, the guide having four parallel angled rails, the two legs of each of which are respectively arranged on two (adjacent) faces of a (virtual) cuboid and provided with fastening devices for releasably fastening the satellite to the guide. [Background technology]

[0002] Such an ejection unit is known from US Pat. No. 5,399,633. The outer dimensions of the imaginary rectangular parallelepiped bounded by the angled rails correspond to the outer dimensions of the satellite, which can be inserted between the angled rails. The satellite may be a satellite according to the CubeSat standard. The satellite is usually brought into orbit by a rocket and released from orbit by an ejection unit. For ejection, the door of the ejection unit is opened and the satellite is pushed out of the guides and thereby released. However, during transportation to orbit, the satellite and the ejection unit are subjected to high accelerations and loads, in particular during the launch of the rocket and the separation of rocket parts, such as the large main satellite. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] DE 102016108606 Summary of the Invention [Problem to be solved by the invention]

[0004] It is therefore an object of the present invention to further develop the ejection unit according to the preamble of claim 1 and to ensure, with a simplified design, a safe and vibration-free fixation of the satellite within the ejection unit. [Means for solving the problem]

[0005] This object is met with the features of claim 1, in particular in that the fastening device comprises at least one fastening mechanism which applies a force to the angled rail only in a direction which forms a bisector of the angled rail.

[0006] According to the invention, the satellite is not fastened at individual discrete positions, but through angled rails that are part of the guide, so that the fastening forces applied to the satellite are distributed uniformly over the entire satellite. Furthermore, the fastening forces are applied to the satellite from a diagonal, not from two adjacent sides, so that very high fastening and damping forces can be achieved with only one fastening mechanism, while taking into account the available installation space conditions and the dimensions of the components. This also simplifies the design considerably.

[0007] Advantageous embodiments of the invention are set out in the description, the drawings and the dependent claims.

[0008] According to a first advantageous embodiment, one of the angled rails can have a leg spaced outward from the adjacent face of the (imaginary) cuboid. In this embodiment, one of the angled rails contacts the satellite with only one leg, while the other leg of the angled rail is spaced from the adjacent side wall of the satellite. This achieves that the fastening forces are only transmitted perpendicular to the surface of the satellite by the associated fastening device that applies the force in an oblique direction. By using two fastening mechanisms of the above-mentioned type, i.e., on the one hand obliquely and on the other perpendicularly to the satellite, even larger satellites (for example size 6U) can be reliably held and damped without the forces of the fastening mechanisms acting on each other.

[0009] If only one angled rail is provided with a fastening mechanism, it is advantageous for the remaining three angled rails to be fixedly attached to the housing, and if two angled rails are provided with fastening mechanisms, it is advantageous for the other two angled rails to be fixedly attached to the housing.

[0010] According to a further advantageous embodiment, at least one fastening mechanism comprises a carriage supported on rollers, which supports a displaceable slot rail supported on the rollers of the carriage. Such a design can advantageously have an inclined slot guide, which allows the forces for fastening the satellite to be deflected on the one hand and amplified on the other hand, improving damping. In this respect, the carriage has two roller systems, i.e. one roller system for low-friction movement of the carriage and a second roller system for moving the displaceable slot rail.

[0011] According to a further advantageous embodiment, a spring-loaded conical bolt is provided, which can fix the ejection carriage of the ejection unit in a blocking position when the ejection carriage is in a preloaded position. The spring-loaded bolt, which is formed with a conical tip, can automatically slide into a blocking position in which the cone of the bolt engages in the opening of the ejection carriage when the ejection carriage is fastened. In order to prevent the conical bolt from being pushed out of the blocking position again by the preloaded ejection carriage, according to a further advantageous embodiment, a locking pin can be provided, which holds the conical bolt in the blocking position as long as the door is not almost completely opened. Thus, only when the door is completely or almost completely opened, the locking pin behind the conical bolt is released, which moves the conical bolt out of the blocking position and releases the ejection carriage, which can then move under the force of the spring in the ejection direction to eject the satellite.

[0012] According to a further advantageous embodiment, at least one fastening mechanism can have a push plunger that abuts against the door and can further have a pull plunger that is actuable by the door and acts by force, for example via a push rod articulated to the door. In this way, the fastening mechanism is tensioned by two mechanisms that operate independently. When the door closes, the push plunger is pushed and the fastening mechanism is actuated. At the same time, the pull plunger can apply a pulling force to the fastening mechanism when the door is closed.

[0013] In the above embodiment, the lock pin advantageously acts as an entrainer for the pull plunger at the end of the door opening movement, thereby providing a redundant mechanism for moving the carriage in the opening direction.

[0014] According to a further advantageous embodiment, the ejection unit can have at least one rigid threaded bolt, which fixes the ejection carriage in a preloaded position in the housing. This facilitates the loading of the satellite and prevents the fastened ejection carriage from moving forward unintentionally. Here, the threaded bolt can be screwed from the outside through the housing to the ejection carriage, which at the same time ensures that the ejection carriage is located in the rear stop and eliminates play between the ejection carriage and the housing. Moreover, such a threaded bolt helps to prevent undesired movements and unnecessary system loads before use in space.

[0015] According to a further advantageous embodiment, at least one fastening pin can be screwed from the outside to the door, which fixes the satellite arranged in the guide in the ejection direction without play. When the satellite is inserted in the guide of the ejection unit and the door is closed, the ejection carriage can be fixed in the housing in a preloaded position as described above. If the fastening pin is then screwed from the front side of the door, play between the satellite and the housing can be eliminated. According to a further advantageous embodiment, the fastening pin can be provided with a plate-like anti-rotation part, to which the fastening pin is screwed on the one hand and which is fixed on the outside of the door by a screw on the other hand. When the screw is loosened, the anti-rotation part can move slightly so that the fastening pin can be screwed to the door. However, when the screw is subsequently tightened, the anti-rotation part tilts slightly and the fastening pin cannot be loosened due to the friction lock in one turn of the thread of the fastening pin.

[0016] According to a further advantageous embodiment, an emergency release device is provided on the outside of the door, allowing the door to be opened manually and / or without power during test or maintenance operations.

[0017] According to a further advantageous embodiment, a door locking device can be provided on the outside of the door for locking the door, which can be operated without tools. Advantageously, the door locking device can be operated with one hand.

[0018] According to a further advantageous embodiment, the housing is provided with a number of service windows, each closed by a plate, one side of which is inserted into the retaining groove and the other side of which is releasably fastened to a fastening element fixed to the housing. In this way, a quick release and fastening of the plate is possible, since it is only necessary to insert the plate into the retaining groove and fasten it to the housing with the fastening element. The fastening element is, for example, a nut that can be screwed onto a threaded pin, which is provided at its outer end with an end piece that can prevent the nut from loosening completely.

[0019] The invention will now be described, purely by way of example, with reference to preferred embodiments and the accompanying drawings, in which: [Brief description of the drawings]

[0020] [Figure 1] FIG. [Diagram 2] 2 is a longitudinal section taken along line II-II in FIG. 1 with the door open. [Diagram 3] FIG. 3 is a vertical cross-sectional view corresponding to FIG. 2 with the door closed. [Figure 4] FIG. 4 is an enlarged view of the lower right region of FIG. [Diagram 5] FIG. 2 is a plan view of the lower right discharge chute of FIG. 1 with the door open. [Figure 6] FIG. 13 is a plan view of a discharge unit according to a further embodiment with the door open. [Figure 7] FIG. 7 is an enlarged view of the lower right region of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Figure 1 shows a perspective view of an exemplary embodiment of an ejection unit for a total of four cuboid satellites. The ejection unit likewise comprises a cuboid housing 10, in which a total of four ejection shafts are provided, one for each satellite, numbered 1 to 4. Each ejection chute is closed by a door 12, 14, 16, 18, the doors 12 and 14 being pivotable about axis A and the doors 16 and 18 being pivotable about axis B, allowing the ejection of the satellites. Each door is locked by a locking unit, not shown in detail, and can be unlocked by a remote control.

[0022] As further shown in Fig. 1, the housing is provided with a number of service windows 20, each of which is closed by a plate 22. Each plate is inserted on one side into a retaining groove 24 formed in the housing and is removably fixed on the other side to a fastening element 26 fixed to the housing 10. In the illustrated embodiment, the fastening element is a nut screwed onto a threaded pin, with a cap 28 on the upper side to prevent the nut from loosening. Each plate 22 is flexible and has a recess in the area of ​​the fastening element that is open outward on one side, so that after insertion into the retaining groove 24, each plate 22 can be inserted under the nut 26 and then screwed in.

[0023] Furthermore, in Fig. 1 it can be seen that two fixing pins 30 are screwed from the outside of each door, penetrating the door and serving to fix the satellite in the ejection direction without play. Each fixing pin 30 is screwed here via an anti-rotation part in the form of a small plate 32, which can be fixedly screwed to the outside of the door by means of a screw 34. When the screw 34 is loosened, the fixing pin 30 can be screwed to the door via the small plate 32. Then, when the screw 34 is tightened, the small plate 32 tilts in the thread of the fixing pin 30, which prevents the fixing pin from coming off the door.

[0024] 1 also shows that a door locking device is provided on the outside of each door, consisting of two pins 36, 38 that can be pressed without tools using thumb and index finger to lock each door. Also provided on the outside of each door is an emergency release device 40 that can be activated using a tool.

[0025] Each door is provided with a contact element 15 on the front of the housing 10, which shorts two contact pins when the door is fully open, so that when the satellite is released it can be checked whether the door is fully open. Each door can also be fitted with a magnetic switch on the housing 10, which can detect when it is fully closed.

[0026] FIG. 5 shows a plan view of part of the ejection unit of FIG. 1, namely the ejection chute 4 with the door 18 open. As can be seen, the housing 10 is provided with a four-sided satellite guide for accommodating each satellite, consisting of a total of four angled rails 50, 52, 54, 56 arranged parallel to one another, with two legs 50a, 50b, 52a, 52b, 54a, 54b, 56a, 56b each arranged on two adjacent faces of an (imaginary) rectangular parallelepiped Q shown in FIG. 5 by dashed lines. This imaginary rectangular parallelepiped Q corresponds to the outer dimensions of the satellite to be ejected and extends over its length into the plane of the drawing. Thus, the satellites inserted into the guides formed by the angled rails 50-56 are guided and held on each outside by two legs of those guide rails.

[0027] To releasably fasten the satellite to the guide, in the illustrated embodiment, the angled rail 54 is provided with a fastening arrangement, described in more detail below. The fastening arrangement has a fastening mechanism that applies a force to the angled rail 54 only in a direction W that forms a bisector of the angled rail. Thus, force is only applied obliquely to the satellite. The remaining three angled rails 50, 52, 56 are fixedly attached to the housing 10, so that application of a force to the angled rail 54 in the direction of the bisector W can securely fasten and hold the satellite within the housing 10.

[0028] 2 and 3 show cross-sectional views along line II-II in FIG. 1 with the door open (FIG. 2) and closed (FIG. 3) respectively. As shown in FIG. 2 in this respect, the angled rail 54 is fixed to a displaceable slot rail 60, which is supported on a roller 62 of a carriage 64 supported on a roller 66, which is movable in an ejection direction E. A push plunger 68 serves to move the carriage 64 against the ejection direction E, which, when the door 18 is closed, abuts against the rear surface of the door and moves the carriage 64 against the ejection direction E against the force of a spring 70. By moving the carriage 64 against the ejection direction E, the roller 62 moves in a slot guide 72 which extends obliquely to the ejection direction E and which has a pitch of 6:1 in the illustrated embodiment. This movement of 6 units of the carriage 64 causes a movement of 1 unit of the slot rail 60 and therefore of the angle profile 54. Conversely, the forces acting on the angled rail 54 (due to vibrations of the satellite) are reduced by a factor of six, so that even severe vibrations can be adequately damped.

[0029] A further component of the fastening mechanism of the angled rail 54 is a push rod 74 which is connected at its front end via a joint 76 to the door 18 and at its rear end to a pull plunger 78 which pulls the carriage 64 rearward against the force of a spring 80, against the ejection direction E. A locking pin 82 is connected to the pull plunger 78 and is pressed behind a spring-loaded conical bolt 84 which is used to secure the ejection carriage 90, as will be described in more detail below.

[0030] As shown in Fig. 5, the ejection carriage 90 runs along all four angled rails 50-56 and the ejection of the satellite is performed by the ejection spring 92. To hold the ejection carriage 90 in the preloaded rear position (Figs. 2-4), the conical bolt 84, which is provided with a cone on the front side, engages in a corresponding recess 85 of the ejection carriage 90. Here Fig. 4 shows a position in which the ejection carriage 90 has not yet been moved completely to the rear end position (see also Fig. 2). But in this case (Fig. 3), the conical bolt 84 is pressed by the spring 87 into the recess 85 of the ejection carriage 90, thereby fixing the ejection carriage 90 in the blocking position of the conical bolt 84. Due to the conical shape of the conical bolt 84, the ejection carriage 90 can initially slide on the conical bolt 84 until the conical bolt 84 engages in the recess 85. To prevent the conical bolt 84 from being released from the blocking position, the conical bolt 84 is blocked at its rear end by a locking pin 82, unless the door 18 is fully or almost fully open. Only when the door 18 reaches the open position, the push rod 74 moves sufficiently in the ejection direction E to release the conical bolt 84 at the rear. At this moment, the force of the ejection spring 92 moves the ejection carriage 90 in the ejection direction E, ejecting the satellites on the angled rail. During this movement, the locking pin 82 also acts as an entrainer for the pull plunger 78. That is, if the force of the compression spring 94 (FIG. 4) is not sufficient to move the carriage 64 in the ejection direction E, the locking pin 82 pushes the pull plunger 78 from behind, which forces the pull plunger 78 to move in the ejection direction E.

[0031] To load a satellite into the ejection chute of the ejection unit described above, the ejection carriage 90 is first moved against the ejection direction E to the rear end of the ejection chute and the ejection spring 92 is compressed. In this position, the ejection carriage is first fixed in a preloaded position to the housing 10 using the spring-loaded threaded bolt, and the ejection carriage 90 slides over the spring-loaded threaded bolt until it engages with the fixing opening. This makes it unnecessary to manually hold the ejection carriage 90 in the preloaded position.

[0032] Next, one or more threaded bolts are screwed from the rear of the housing 10 through the housing into the ejection carriage 90, fixing the ejection carriage 90 in its rearmost position, thereby simultaneously providing a transport fixing device. The satellite can then be inserted into the ejection chute and pushed with its four outer edges into each of the angled rails 50-56. After that, when the door 18 is closed, the inside of the door 18 is pressed against the force of the push plunger 68 and the spring 70, causing the carriage 64 to move backwards against the ejection direction E, thereby moving the slotted rail 60 in the direction W by the oblique slot guide (FIG. 5). At the same time, the push rod 74 is pushed backwards through the joint 76, which in turn pushes the carriage 64 backwards against the force of the spring 80 until the lock pin 82 engages behind the conical bolt 84. This locks the ejection carriage 90, allowing the satellite to be ejected after removing the rigid threaded bolt and the spring-loaded threaded bolt. In this state, the satellite is pressed against the angled rails 50, 52, 56 by the force of the springs 70, 80 through the angled rail 54. After the launch of the rocket, due to the occurrence of acceleration, the satellite exerts a force on the angled rail 54 and therefore also on the slotted rail 60, which is deflected through the 6:1 pitch to the carriage 64, which covers a distance six times that of the slotted rail 60. In the process, the movement of the carriage 64 is damped by the two springs 70 and 80. If the maximum force of these springs is, for example, 200 N, this means that the damping system damps the satellite with 2400 N.

[0033] When the satellite is to be released into space, the door is unlocked by remote control and opens via a spring, the details of which are not shown. This releases the push plunger 68 again, and when the door opens, the push rod 74 starts to move forward in the release direction E, which also moves the push plunger 78 in the release direction E. When the two springs 70, 80 no longer exert a force on the carriage 64, the carriage 64 is pushed forward in the release direction E by the compression spring 94, and this movement retracts the slot rail 60 through the oblique slot guide 72, so that the satellite is no longer fixed in the guide. At the final opening angle of the door 18, the locking pin 82 is forced out behind the conical bolt 84 by the push rod 74, which pushes the conical bolt 84 out of the release carriage 90, which is then moved in the release direction E by the release spring 92, and the satellite is released.

[0034] 6 and 7 show further embodiments of the discharge unit, where the same components are given the same reference numbers and only the differences are described. The discharge unit shown in FIG. 6 is provided with a total of three discharge chutes that can be closed by doors 12, 13, 14, the lower discharge chute that can be closed by door 13 has twice the volume of the upper discharge chute. The two upper discharge chutes with doors 12, 14 are designed similarly to the previous embodiment examples. The lower discharge chute with door 13 has two fixed position angled rails 50, 52 and an angled rail 54 equipped with a fastening mechanism as described above. A fourth angled rail 55, located on the lower side of the same cuboid Q as the angled rail 54, is also equipped with a fastening mechanism as described above. However, the design of the angled rail 55 differs from that of the angled rail 54, which will be described in more detail with reference to FIG. 7.

[0035] As shown in FIG. 7, the angled rail 55 also has two legs 55a and 55b extending at right angles to each other, with leg 55b (the horizontal leg in the figure) then being located on the underside of the cuboid Q. However, the other leg 55a (the vertical leg in the figure) of the angled rail 55 is spaced outwardly from the adjacent face of the cuboid Q by a distance D. This ensures that the angled rail 55 does not hit the satellites filling the space of the cuboid Q with leg 55a. The fastening mechanism of the angled rail 55 exerts a force F acting parallel to the bisector of the angled rail 55. However, since leg 55a is spaced by the distance D from the cuboid Q and does not contact the satellites, this force F only acts vertically on the satellites inserted into the release chute. In this way, the satellite can be strongly damped and easily held in the ejection chute by the two fastening mechanisms on the angled rails 54, 55, but the two fastening mechanisms do not work against each other.

Claims

1. A release unit for at least one rectangular parallelepiped satellite, said release unit comprising a housing (10) closed by at least one door (12-18) and provided with a guide for receiving the satellite, said guide comprising four parallel angled rails (50-56) each having two legs (52a-54b, 55b, 56a, 56b), said two legs (52a-54b, 55b, 56a, 56b) respectively arranged on two faces of a rectangular parallelepiped (Q), and a fastening device for releasably fastening said satellite to said guide, The ejection unit, wherein the fastening device comprises at least one fastening mechanism that applies force to one angled rail (54) only in a direction (W) that forms a bisector of the angled rail (54).

2. 2. The discharge unit according to claim 1, characterized in that one of the angled rails (55) has a leg (55a) spaced outwardly from an adjacent face of the cuboid (Q) by a distance (D).

3. 3. The discharge unit according to claim 1 or 2, characterized in that two or three of the angled rails are fixedly attached to the housing (10).

4. 4. The ejection unit according to claim 1, wherein the at least one fastening mechanism comprises a carriage (64) supported on rollers (62), the carriage (64) supporting a displaceable slot rail (60) supported on rollers (66) of the carriage (64).

5. 5. The ejection unit according to claim 1, further comprising a spring-loaded conical bolt (84) for fixing the ejection carriage (90) in a blocking position when the ejection carriage (90) is in a preloaded position.

6. 6. A discharge unit according to claim 5, characterized in that the conical bolt (84) is held in the blocking position by a locking pin (82) unless the door (12-18) is substantially fully open.

7. The discharge unit according to any one of claims 1 to 6, characterized in that the at least one fastening mechanism comprises a push plunger (68) abutting against the door (12-18) and a pull plunger (78) actuable by the door (12-18) and acted upon by a force via a push rod (74) articulated to the door (12-18).

8. The discharge unit according to claim 6 or 7, characterized in that, at the end of the opening movement of the door (12-18), the lock pin (82) acts as an interlocking part for a pull plunger (78).

9. The ejection unit according to any one of the preceding claims, characterized in that at least one rigid threaded bolt is provided for fixing the ejection carriage (90) in a preloaded position in said housing (10).

10. 10. The ejection unit according to any one of the preceding claims, characterized in that at least one spring-loaded threaded bolt is provided for fixing the ejection carriage (90) in a preloaded position in said housing (10).

11. The ejection unit according to any one of claims 1 to 10, characterized in that at least one fixing pin (30) is screwed from the outside into the door (12-18) to fix the satellite arranged in the guide without play in the ejection direction (E).

12. The discharge unit according to claim 11, characterized in that the fixing pin (30) is screwed through a plate-like anti-rotation part (32) fixed to the outside of the door (12-18) by means of a screw (34).

13. Discharge unit according to any one of the preceding claims, characterized in that an emergency release device is provided on the outside of the door (12-18).

14. 14. The discharge unit according to claim 1, further comprising a door locking device (36, 38) on the outside of said doors (12-18) which can be operated without tools.

15. The discharge unit according to any one of the preceding claims, characterized in that the housing (10) is provided with a service window (20) closed by a plate (22) which is inserted on one side into a retaining groove (24) and is releasably fixed on the other side to a fastening element (26) fixed to the housing (10).

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