| 说明书全文 |
TECHNICAL FIELD This invention relates generally to door latch systems, and more particularly, to a door migration prevention system. The invention further relates to a method of reducing the migration of a door. BACKGROUND A rotorcraft may include one or more rotor systems. One example of a rotorcraft rotor system is a main rotor system. A main rotor system may generate aerodynamic lift to support the weight of the rotorcraft in flight and thrust to counteract aerodynamic drag and move the rotorcraft in forward flight. Another example of a rotorcraft rotor system is a tail rotor system. A tail rotor system may generate thrust in the same direction as the main rotor system's rotation to counter the torque effect created by the main rotor system. DE3738367 discloses a closing device for motor vehicles, which operates independently of the door lock, having an energy accumulator, a closure mechanism and a release mechanism. A guide slot is provided on a door pillar, and a roller is located on the inside of a door, the roller being moved by the energy accumulator in a predetermined path. A guide-slot path has a component in the door closing direction, and a component in the movement direction of the roller. SUMMARY Particular embodiments of the present disclosure may provide one or more technical advantages. A technical advantage of one embodiment may include the capability to prevent or reduce migration of doors due to vibration. Certain embodiments of the present disclosure may include some, all, or none of the above advantages. One or more other technical advantages may be readily apparent to those skilled in the art from the figures, descriptions, and claims included herein. BRIEF DESCRIPTION OF THE DRAWINGS To provide a more complete understanding of the present invention and the features and advantages thereof, reference is made to the following description taken in conjunction with the accompanying drawings, in which: - FIGURE 1 shows a rotorcraft according to one example embodiment;
- FIGURE 2 shows the door of the rotorcraft of FIGURE 1 and two door latch systems according to one example embodiment;
- FIGURE 3 shows a detailed perspective view of one of the door latch systems of FIGURE 2;
- FIGURE 4 shows a perspective view of the fork, roller element, receiver, and frame attachment device of the door latch system of FIGURE 3;
- FIGURE 5 shows a cross-section perspective view of the door latch system of FIGURE 3;
- FIGURE 6 shows a simplified view of the cross-section of FIGURE 5 with elements such as the door attachment device and the fork removed; and
- FIGURE 7 shows a cross-section view of the roller element and receiver of FIGURE 6.
DETAILED DESCRIPTION OF THE DRAWINGS FIGURE 1 shows a rotorcraft 100 according to one example embodiment. In the example of FIGURE 1, rotorcraft 100 features a rotor system 110, blades 120, a fuselage 130, a landing gear 140, and an empennage 150. Rotor system 110 may rotate blades 120. Rotor system 110 may include a control system for selectively controlling the pitch of each blade 120 in order to selectively control direction, thrust, and lift of rotorcraft 100. Fuselage 130 represents the body of rotorcraft 100 and may be coupled to rotor system 110 such that rotor system 110 and blades 120 may move fuselage 130 through the air. Landing gear 140 supports rotorcraft 100 when rotorcraft 100 is landing and/or when rotorcraft 100 is at rest on the ground. Empennage 150 represents the tail section of the aircraft and features components of a rotor system 110 and blades 120'. Blades 120' may provide thrust in the same direction as the rotation of blades 120 so as to counter the torque effect created by rotor system 110 and blades 120. Teachings of certain embodiments recognize that blades 120' may represent one example of a secondary rotor system; other examples may include, but are not limited to, forward-thrust propellers (e.g., pusher propellers, tractor propellers, etc.), tail anti-torque propellers, ducted rotors, and ducted fans mounted inside and/or outside the rotorcraft. Teachings of certain embodiments relating to rotor systems described herein may apply to rotor system 110 and/or other rotor systems, such as other tilt rotor and helicopter rotor systems. It should also be appreciated that teachings from rotorcraft 100 may apply to aircraft other than rotorcraft, such as airplanes and unmanned aircraft, to name a few examples. In some embodiments, rotorcraft 100 may include a variety of additional components not shown in FIGURE 1. For example, rotor system 110 may include components such as a power train, drive shafts, a hub, a swashplate, and pitch links. In some embodiments, rotorcraft 100 also features a door 160. In the example of FIGURE 1, door 160 is a sliding side door. In this example, rotorcraft 100 may also feature a door-sliding system configured to slide door 160 from an open position to a closed position. During operation of rotorcraft 100, door 160 may be subject to various vibrations and other forces. These forces may cause door 160 to migrate away from a center position. Migration of door 160, however, may result in a variety of issues, such as unwanted gaps between door 160 and the door frame, failure of door 160 (e.g., fatigue failure of door components), and noise due to vibration of door 160. Accordingly, teachings of certain embodiments recognize the capability to prevent or reduce migration of doors such as door 160. Teachings of certain embodiments recognize the capability to prevent migration of doors in a variety of environments, such as aircraft doors (e.g., rotorcraft doors) where vibrations may be prevalent. FIGURES 2-7 show various views of a door latch system 200 according to one example embodiment. FIGURE 2 shows a perspective view of two door latch systems 200 securing door 160 against a door frame 170 of rotorcraft 100. FIGURE 3 shows a detailed perspective view of one of the door latch systems 200 of FIGURE 2. In the example of FIGURE 3, door latch system 200 includes a door attachment device 210, a roller assembly 220 (including a fork 222 and a roller element 224), a receiver 230, and a frame attachment device 240. FIGURE 4 shows a perspective view of the fork 222, roller element 224, receiver 230, and frame attachment device 240 of the door latch system 200 of FIGURE 3. FIGURE 5 shows a cross-section perspective view of the door latch system 200 of FIGURE 3. FIGURE 6 shows a simplified view of the cross-section of FIGURE 5 with elements such as door attachment device 210 and fork 222 removed. FIGURE 7 shows a cross-section view of the roller element 224 and receiver 230 of FIGURE 6. In operation, according to one example embodiment, a door-sliding system may be configured to slide door 160 from an open position to a closed position within door frame 170. To slide door 160 open, a user may retract door handle 162, as seen in FIGURE 2. Retracting door handle 162 may cause door attachment device 210 to retract fork 222 and roller element 224, as seen in FIGURE 5. Retracting roller element 224 may disengages roller element 224 from receiver 230, which frees door 160 to slide away from door frame 170. To close door 160, a user may slide door 160 back towards door frame 170 until receiver 230 receives roller element 224 and door 160 is sealed against door frame 170 via door seal 165. In the example of FIGURES 2 and 3, door attachment device 210 is coupled to door 160 and is in mechanical communication with door handle 162. Frame attachment device 240 couples receiver 230 to structure 175, which is located proximate to door frame 170. One example of frame attachment device 240 may include a bracket with one or more bolt holes. As seen in the example of FIGURE 4, receiver 230 and frame attachment device 240 may manufactured as a single, integral component. Teachings of certain embodiments recognize that each door latch system 200 may prevent or reduce migration of door 160. For example, door latch system 200 may respond to movement (e.g., migration) of door 160 by moving door 160 closer to door frame 170. Moving door 160 closer to door frame 170 may compress door seal 165 and result in a tighter seal between door 160 and door frame 170. As seen in the example of FIGURES 6 and 7, receiver 230 features a non-planar receiving surface configured to move door 160 closer to door frame 170 in response to movement of door 160. This non-planar receiving surface, for example, may be oriented relative to door frame 170 such that roller assembly 220 causes door attachment device 210 to move door 160 closer to door frame 170 as roller assembly 220 moves along a path at least partially defined by the receiving surface. For example, FIGURES 6 and 7 show a coordinate system with axes 200a, 200b, and 200c, and centered at a point of reference. As seen in the example of FIGURES 6 and 7, axis 200b is perpendicular to axis 200a, and axis 200c is perpendicular to the plane formed by axes 200a and 200b. Although axes 200a, 200b, and 200c are drawn relative to a single point of reference, teachings of certain embodiments recognize that this coordinate system may be defined relative to a variety of points of reference. In addition, axis 200c may be drawn in a variety of locations and not necessarily intersect at the same point where axes 200a and 200b intersect. In the example of FIGURES 6 and 7, receiver 230 may be configured to receive roller element 224 in a direction parallel to axis 200a as door 160 is opened and closed. As seen in the example of FIGURE 6, roller element 224 may move in the direction of axis 200c as receiver 230 receives roller element 224 in a direction parallel to axis 200a due to the curvature of receiver 230, but ideally roller element 224 would not move in a direction parallel to axis 200b. Roller element 224 may be prone to move in a direction parallel to axis 200b, as a result of vibrations and other forces. In some embodiments, movement of roller element 224 in a direction parallel to axis 200b may represent one example of door migration. If roller element 224 does move in a direction parallel to axis 200b, receiver 230 may reposition roller element 224 in a direction parallel to axis 200c such that roller element 224 moves door 160 closer to door frame 170. For example, as seen in FIGURE 7, receiver 230 may feature curved surface portions 235 separated by a surface portion 237. Surface portion 237 may be configured to at least partially receive roller element 224, but roller element 224 may move towards one of the curved surface portions 235 as a result of door migration. Curved surface portions 235 are configured relative to door frame 170 such that the distance between door frame 170 and curved surface portions 235 increases at various points along curved surface portions 235 as one moves further away from surface portion 237. In some embodiments, the curved surface portions 235 are symmetric to each other. As roller element 224 rolls up or down (in a direction parallel to axis 200b), roller element 224 may roll from surface portion 237 to one of the curved surface portions 235. Curved surface portions 235 may be configured relative door frame 170 such that roller element 224 moves away from door frame 170 (in a direction parallel to axis 200c) as roller element 224 moves up or down away from surface portion 237 (in a direction parallel to axis 200b). Moving roller element 224 away from door frame 170 may cause door 160 to move closer to door frame 170 and form a tighter seal against door frame 170. In this example, curved surface portions 235 and surface portion 237 may at least partially define a migration path of roller element 224. This migration path may include, for example, the path of roller element 224 as roller element 224 moves from surface portion 237 to one of the curved surface portions 235. As roller element 224 migrates along one of the curved surface portions 235, the curved surface portion 235 may continue to move roller element 224 away from door frame 170 (in a direction parallel to axis 200c), which may cause door 160 to form a tighter seal against door frame 170. Teachings of certain embodiments recognize that door latch system 200 may eventually prevent further migration by creating a seal so tight between door 160 and door frame 170 that door 160 no longer migrates. For example, the seal between door 160 and door frame 170 may become so tight that the seal is stronger than the vibration forces that caused the initial migration. Modifications, additions, or omissions may be made to the systems and apparatuses described herein without departing from the scope of the invention. as defined by the claims. The components of the systems and apparatuses may be integrated or separated. Moreover, the operations of the systems and apparatuses may be performed by more, fewer, or other components. The methods may include more, fewer, or other steps. Additionally, steps may be performed in any suitable order. Although several embodiments have been illustrated and described in detail, it will be recognized that the scope of the present invention is defined by the appended claims. |
