Balance load actuator

The present invention provides a balance load actuator for effecting motion between a first part and a second part. An embodiment of the present invention comprises a main housing; a shaft; a motion transfer assembly; and a load balancing assembly. The balance load actuator receives substantial external loads through a load balance assembly and distributes the loads to the main housing, thus relieving undue stress otherwise exerted on the shaft and enabling lighter and smaller design components and construct.

BACKGROUND OF THE INVENTION

The present invention generally relates to actuators and, more particularly, to actuators for aircraft.

Current technology includes actuator devices movable between an operative position and inoperative position, for instance, facilitating movement of a door panel between a closed position and an open position relative to a structural member. Such devices often employ a motor and gear assembly to facilitate moving the door panel to an open position, and a spring assembly or other tension mechanism to store energy and transfer the stored energy upon extension or compression to, for example, effect closure of the door panel.

Aircraft door actuators are typically designed according to specific, predetermined load tolerances. For example, various actuators are designed to withstand in-flight loads such as low-altitude external air pressure and high-altitude internal air pressure. Other actuators are designed to withstand relatively greater loads, including high-pressure liquid forces exerted on the aircraft during de-icing processes or in-flight ice-breaking load for opening a door under emergency circumstances. In general, the weight of an actuator and the size of its components increase correlatively to its associated loads. Therefore, actuators designed for relatively significant loads are typically relatively heavy in weight and large in size, resulting in increased production and performance costs.

For example, a linear drive power door operator disclosed in U.S. Pat. No. 5,513,467 to Current et al. includes an elongate closer body housing; a power screw disposed therein; a drive; a rack and pinion assembly; a link arm; and a control device. An actuator disclosed in U.S. Pat. No. 2,387,800 to Leland et al. includes a closure member; a spring loaded shifter connected to the closure member and operative to actuate said member; a latch engaging said shifter and releasably holding it in spring loaded position; a screw shaft with a non-rotatable nut threaded thereon; and means on said nut to engage the latch and release said shaft and to strike said shifter and start it on its spring actuated movement.

As can be seen, there is a need for an improved method and apparatus, such as an actuator, to move a first member to various positions relative to a second member. Further, there is a need for such an actuator to withstand significant load forces. Finally, there is a need for such an actuator to be designed, manufactured, and transported in a cost-efficient manner while exhibiting characteristics such as a lightweight design and embodiment.

SUMMARY OF THE INVENTION

An aspect of the present invention includes a main housing; a motion transfer assembly mechanically associated with the housing; and a load balancing assembly mechanically associated with the housing.

Another aspect of the present invention includes a main housing having a tail end connected to a structural member; a shaft embedded inside, or otherwise mechanically associated with, the main housing; a gear assembly mechanically associated with the shaft and the main housing; a motor mechanically associated with the shaft and the gear assembly; a rod end having an eye, a shank, and a foot; the eye of the rod end connected to a movable member or door frame and the foot of the rod end mechanically associated with the shaft; a spring housing having a base and a side; a connector affixing the base of the spring housing to the main housing; a spring having one end and a distal end, the one end affixed to the base of the spring housing; and an end cap to which the distal end of the spring is affixed, the end cap substantially surrounding and interacting with the shank of the rod end.

Yet another aspect of the present inventions includes a main housing having a tail end connected to an aircraft structure and a rod end connected to the door panel; a shaft connected to the main housing; a gear assembly mechanically associated with the shaft and the housing; a motor mechanically associated with the shaft and the gear assembly; a rod end having an eye, a shank and a foot; the eye of the rod end connected to a movable member and the foot of the rod end mechanically associated with the shaft; a spring housing having a side and a base, the base having a threaded joint integrally or independently (as a connector) articulated to the main housing; a spring having one end and a distal end, the one end affixed to the base of the spring housing; a disk forming an aperture therein, the disk having an inside diameter with threading mechanically associated with the shank of the rod end, an outside perimeter area to which the distal end of the spring is affixed, and a beveled edge; a latch assembly connecting the side of the spring housing and the end cap; and a solenoid device mechanically associated with the latch assembly.

A further aspect of the invention includes an aircraft structure; a movable member or door frame; a main housing having a tail end connected to the aircraft structure; a rod end having an eye, a shank, and a foot; the eye of the rod end connected to the movable member; a shaft mechanically associated with the foot of the rod end; a gear assembly mechanically associated with the shaft and the housing; a motor mechanically associated with the shaft and the main housing; a spring housing having a base and a side; a spring having one end and a distal end, the one end affixed to the base of the spring housing; and an end cap affixed to the distal end of the spring.

A method of the present invention includes the steps of transferring motion from a motion transfer assembly to a shaft associated with a main housing to selectively extend and retract the shaft from and into the main housing; receiving a load from an external source by a load balancing assembly; and transferring the load from the load balancing assembly to the main housing and to a structural member.

Another method of the present invention includes the steps of transferring motion from a motor to a shaft via a gear assembly, the shaft and the gear assembly associated with a main housing; selectively expanding and compressing a spring attached to spring housing and an end cap, the end cap surrounding and interacting with a rod end attached to the shaft; and transferring a load from an external source to the main housing via the rod end, the end cap, and the spring.

DETAILED DESCRIPTION OF THE INVENTION

Broadly, the balance load actuator of the present invention provides superior initial load in a lightweight, efficient construct. It is contemplated that the present invention may be used,inter alia, in aircraft and other mechanical environments wherein the actuator must sustain substantial forces exerted on it from external sources. For example, the contemplated uses include employment as a load balancing actuator for opening and closing an aircraft door panel, whereby the present invention facilitates selective movement of the door panel and overcomes the restraining loads such as breaking the ice formed around the door panel as well as typical in-flight air pressures. The balance load actuator of the present invention achieves these results by a load balancing assembly for transferring or distributing said forces to preselected components of the balance load actuator. In contrast, actuators of the prior art lack means to selectively distribute or balance these forces. In operation, the prior art actuators receive external forces via a connector component facilitating a connection between door panels or structural members and an actuator shaft. The connector component transfers and distributes these forces directly to a motion transfer component, such as a shaft, gear train and motor. The shaft must be heavy and large enough to withstand such forces. The relatively heavy weight and large size of the shafts, gear train and motor of prior art actuators present a distinct disadvantage in terms of increased costs of materials, production, shipping, and operation, where overall aircraft design and performance must accommodate such unwieldy components.

More specifically, the present invention may provide a main housing that comprises a structural support member capable of housing one or more components of the motion transfer assembly. Upon selective actuation, one or more components of the motion transfer assembly may move axially from a first position substantially within the main housing to a second position, extending substantially outside of the main housing. Further selective actuation can retract the component along the same axis, re-housing the component in the main housing.

Independent of actuation and without regard to a specific position of components of the motion transfer assembly, the load balancing assembly of the present invention functions to receive an external load and transfer the load directly into the main housing, thus providing substantial load resistance despite a relatively lightweight construction; or to provide a predetermined spring force to offset the required external forces such as ice-breaking loads.

Referring now to the drawings, wherein similar reference characters designate corresponding parts throughout the drawings, there is shown an embodiment of a balance load actuator10according to the present invention. The balance load actuator10may be used in conjunction with an aircraft assembly to open and close, for example, a door panel12. The balance load actuator may be mounted on the door panel12via a door frame14and a structural member16. Actuation can extend or retract one or more components of the balance load actuator10, exerting a force11on the door panel12and effecting the opening or closure of the door panel12, hinged along a hinge line18. The balance load adaptor10is well adapted to withstand loads13such as ice formations20as shown on the door panel12, as well as high-pressure removal of the ice formations via fluid dispersion.

With reference toFIG. 2, there is shown a cross-sectional view taken along line2—2ofFIG. 1of the balance load actuator10in a retracted position, shown relative to line17. The balance load actuator10, or various components thereof, may extend axially along phantom line21, for example, to a second position, shown relative to line19, according to an embodiment of the present invention. The balance load actuator10may comprise, for example, a main housing22, a motion transfer assembly24, and a load balancing assembly26.

The motion transfer assembly24may comprise, for example, a motor28, a gear assembly30, and a shaft32supported by the main housing22, all of which may be operatively connected in the fashion described below. A tail end34of the main housing22may be connected, for example, to the structural member16.

The load balancing assembly26may comprise, for example, a spring housing36having a base38and sides40removably or fixedly attached to the main housing22by, for example, a threaded joint42. The spring housing36may house a spring42, such as a coiled spring, having one end46affixed to the base38of the spring housing36, and having a distal end48connected to an end cap50having an aperture (not shown). A rod end52(having an eye54, a shank56, and a foot58) may engage the shaft32; i.e., upon extension of the shaft32, an end60of the shaft32may contact the foot58of the rod end52. The rod end32can pass through the aperture (not shown) of the end cap50, where the shank56of the rod end52can be mechanically associated with an inside diameter (not shown) of the end cap50. The eye54of the rod end52can be attached to, for example, the movable door frame14.

With continuing reference toFIG. 2, in operation, the motor28may transfer energy, and therefore, motion to the gear assembly30, which is in mechanical communication with the shaft32. As a skilled artisan will note, gear assemblies are well known in the art. Therefore, any combination of components necessary to carry out the function described herein may be employed. The gear assembly30can drive the shaft32; i.e., extend or retract the shaft32from or into the main housing22. Upon extension of the shaft32, the end60of the shaft32may contact the foot58of the rod end52, resulting in applied force44bon the main housing22, which exerts a force34aupon its tail end34to the structural member16. The exertion forces44bmove the doorpanel12from a closed position to an open position, relative to the structuralmember16. Similarly, retraction of the shaft32into the main housing22may cause the door panel12to move from the open position to the closed position. During operation, the rod end52may be axially transferred from a first position to a second position.

Selective motion transfer to the rod end52may also result in a force52aexerted against the end cap50by the rod end52, driving the end cap50axially in a direction away from the tail end34of the main housing22, thus axially expanding the spring44from the base38of the spring housing36to, for example, the position shown by line23, where the rod end52is shown in phantom. The extended spring44may be used to create a pulling force42afor example, to selectively urge themain housing22and its tail end34away from the structural member16, in effect pulling the door panel12to a closed position relative to the structural member16. Conversely, the spring44may be selectively compressed and used to create a pushing force54afor various functions such as urging the rod end52toward the door frame14.

Most notably, however, the spring40can function to distribute external loads exerted on the balance load actuator10, particularly the shaft32. For example, a force46aexerted on shaft32can be transferred—via the foot58of the rod end52—to the shank56of the rod end52. The shank56of the rod end52may then distribute, as depicted by arrow52a, the load to the end cap50and the distal end58of the spring44. The spring44may disseminate the load44avia its one end46through the base38of the spring housing36to the main housing22via the threaded joint42. In various other embodiments, for example, the motor28may reverse a turning direction to extend the shaft32via the gear assembly30, thereafter transferring motion from the spring44in an initially compressed state, directly to the load. In this manner, the shaft32is relieved of various forces exerted upon it, resulting in various actuator designs and embodiments comprising smaller, lighter structures within the scope of the present invention.

Turning now toFIGS. 3aand3b, there are respectively shown a side view and a cross-sectional view of the spring44according to an embodiment of the present invention.FIG. 3bis taken along line3b—3bofFIG. 3a. It is contemplated that the spring44may present with a predetermined free height64and compresses to a predetermined compressed height68. The spring44may compress and expand along an axis62.

With reference now toFIGS. 4aand4b, there are respectively shown a top view and a cross-sectional view of a disk68according to an embodiment of the present invention.FIG. 4bis taken along line4b—4bofFIG. 4a.In various embodiments, the end cap50may comprise the disk68forming an aperture70therein. The disk68may include an inside diameter70with threading for affixation to the shank56of the rod end52. The disk68may comprise a beveled edge74for mechanical association with the distal end48of the spring44, the sides40of the spring housing36, or both. In various embodiments, the distal end48of the spring44may be affixed to an outside perimeter area76.

Alternatively, the balance load actuator may comprise a latch assembly (not shown) and a solenoid device (not shown). The latch assembly may latch the end cap50to the spring housing36. The solenoid device, in electrical communication with the latching assembly, may unlatch the end cap50from the spring housing36, thereby eliminating the need for the motor28to supply continuous electric power to keep the spring44in a compressed state. For example, in various embodiments, once the solenoid device unlatches the end cap50, the motor28may reverse a turning direction to extend the shaft32via the gear assembly and the motion may be transferred directly from the spring44, in compressed state, to the load.