This invention relates to the field of actuating and control- ling the motion of a flap on the wing of an aircraft, particular- ly, the "Fowler"-type rearward, downward and rotational movement.

2. DESCRIPTION OF PRIOR ART.

Flaps on aircraft wings serve a variety of purposes includ- ing, for example, an increase in wing lift. This particularly important function of the flap is served by its extending rear- ward and downward from the wing in the so-called "Fowler"-type motion. "Fowler"-type motion creates an increase in the curva- ture or camber of the wing which increases the coefficient of lift. It is desired that the deployment of the flaps, together with the mechanisms for actuating and controlling the "Fowler"- type motion, impart as little drag resistance as possible while the aircraft is cruising.

Both commercial and military aircraft currently employ flap actuating mechanisms that must simultaneously move the flap and structurally support it. This typically is accomplished by a system of tracks and/or cumbersome sets of linkages. These flap drive systems also include a complex gear and motor system.

There are several drawbacks to the above-described systems.

Specifically, the rate at which motion is actuated by a motor and gear system is a restrictive factor limiting useful deployment of the flaps to the proximate time of landing or taking-off.

While this limitation is quite acceptable for ground-based landings, it is problematic for carrier-based landing and take- off which often occur so abruptly that the rate of speed of flap deployment and retraction poses greater safety risk than desired.

Another drawback is that the current tracks and linkages employed to extend and support wing flaps create a disturbance in the airflow around the wing and flap resulting in what was heretofore considered a necessary but added drag and inefficien- cy. This is illustrated in Figures 5A and 5B. The airflow 102 is disturbed when moving around the linkages 100 and 104 used to deploy the flap 103.

A third drawback is the complexity and cumbersomeness of the existing motor and gear systems. This is illustrated in Figure 5A. From an operations and maintenance standpoint, the multi- plicity of working parts which must function together results in a plethora of mechanical elements, the failure of either one of which could endanger the safety of the flap's operation.

An additional drawback is that, currently, the flap moves in two stages. First, as seen in Figure 5A, the flap is moved fore and aft along a track 100, then the flap is pulled up and down by a separate linkage 104.

A final drawback is the number of linkages extending between the forward or rear spar (supporting beams 106, Figure 5A) of the wing and the flap. The greater the number of such linkages, the greater the so-called free play' or wing flutter at the tip of the flap. Free play occurs as a consequence of any slight move- ment in any of such linkages which may arise because of the slight design tolerances in each linkage. In an individual link- age such tolerance may be inconsequential; however, the collec- tive tolerances of the linkages, many of which are interlocked to each other, geometrically magnify the movement into a signifi- cant factor in flight stability.

The following patents illustrate the current state of the prior art.

U.S. Patent No. 2,218,114. This approach utilizes several mechanisms to extend and rotate the flap. The device increases the wing chord length and has a fixed rotational angle. This concept is heavier due to weight which is the result of the many parts required.

U.S. Patent No. 2,246,116. This approach essentially trans- lates the flap via a four-bar mechanism parallel to the airfoil upper moldline. A slight flap rotation is also derived by a link (item 9 of said invention). This link is fastened to the pivot arm (item 4). The flap torsional moments could not be reacted by item 4 as depicted in the disclosure due to its limited size.

If the size is increased, then fit and function are compromised.

U.S. Patent No. 2,282,516. This design approach utilizes external (outside of the outer wing moldline) hinges (item 51) to support the flap (item 3), thus interfering with the airflow.

U.S. Patent No. 2,407,401. This invention uses nine links or mechanical devices to control the motion of the flap. The large number of joints would tend to increase "free play" or flutter of the control surface. This, in turn, would have adverse effects on trailing edge flutter, a very difficult item to correct with so many joints.

U.S. Patent No. 3,203,647. This invention uses two steps to move the wing, increasing its complexity. First, a pivoted bracket (item 126) rotates the flap back, then a piston pushes the flap downward.

U.S. Patent No. 3,756,089. This invention is essentially a method to rotate a simple flap within a narrow space. It does not have a "Fowler-like" motion (move aft, down and rotate the trailing edge down).

U.S. Patent No. 4,405,105. This invention utilizes two sets of control arms (or four linkages per support point to drive the main flap and the auxiliary flap. The design requires an external wing outer mold line fairing to house these linkages and additional overcentering devices, push rods and other mechanisms.

U.S. Patent No. 4,470,569. This invention deals with a locking mechanism. It utilizes a conventional shaped track to support the slat. The locking mechanism does not react flight loads; this is done by the slat track. This invention has complex tracks, rollers and a drive mechanism. Flap motion and locking is performed by the drive cylinder.

OBJECTS OF THE INVENTION It is an object of the present invention to provide an improved flap movement mechanism that is capable of a Fowler-like motion with reduced weight or size.

It is a further object of the present invention to provide a flap movement mechanism with improved control and efficiency.

It is a further object of the present invention to provide a flap movement mechanism without tracks and thus substantially reduced interference with the airflow around the wing.

It is a further object of the present invention to provide a flap movement mechanism which negates the need for complex and cumbersome gears and motors.

It is a further object of the present invention to provide a faster mechanism for both deployment and retraction to offer aircraft greater operational flexibility and safety, particularly for carrier-based aircraft.

It is a further object of the present invention to provide an improved flap movement mechanism with a reduced number of linkages so as to minimize 'free play' or wing flutter.

It is a further object of the present invention to provide a flap movement mechanism with fewer working parts and thus reduced operational and maintenance risks.

SUMMARY OF THE INVENTION The present invention is an apparatus which overcomes the deficiencies in the prior art.

The present invention consists of a mechanism which connects an angled leading edge, or rear-edge spar to the flap of an air- craft wing. Extending from the spar (directly in one case and indirectly in the second case) are two swivel linkages which each rotationally engage a spar support fittings. The spar support fittings, in turn, engage the flap. Also connecting the flap to the spar are a pair of slaving mechanisms. Each slaving mecha- nism comprises a bar attached to the spar by a spherical bearing, at one end of the bar, and attached to the flap by way of a slot- ted bolt. The flap is actuated by a linear actuator with one end fixed to the spar and the other attached to the flap. When the actuator is operated, movement of the flap is initiated quickly in a single stage stream-wise Fowler-like manner.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1A is a perspective view which illustrates the general location of a trailing edge flap embodying the present invention.

Figure 1B is a perspective view which illustrates general elements of the present invention.

Figure lC-1 is a side view (without the flap mechanism) which illustrates the flap in an up and stowed position.

Figure 1C-2 is a side view (without the flap mechanism) which illustrates the spoiler deployed and flap in a stowed position.

Figure 1C-3 is a side view (without the flap mechanism) which illustrates the flap deployed in a downward, rearward manner with the spoiler deflected down to create a "curved" upper surface and a "nozzle" between wing and flap.

Figure 2 illustrates a perspective, partial cut-away view of the present invention.

Figure 2A illustrates an exploded view of swivel link and slaving mechanisms from Figure 2.

Figure 3A illustrates the same side view as Figure 1C-1 but showing the swivel link and mechanisms of Figure 2.

Figure 3B illustrates the same side view as Figure 1C-3 but showing the swivel link and mechanism of Figure 2.

Figures 4A and 4B illustrate an overhead view of the swivel link and slaving mechanism when the flap is first stowed and then deployed downward.

Figure 4B-1 illustrates a side view of the stowed flap.

Figure 4B-3 illustrates an overhead view along 4B-3 o 4B-3 of the swivel link and slaving mechanism when the flap is in a partially deployed position.

Figure 5A is a cut-away perspective view of a typical prior wing and flap movement assembly.

Figure 5B is a side view from a prior art Figure 5A type deployment illustrating the air flow on a typical prior art wing and flap assembly.

DETAILED DESCRIPTION OF THE INVENTION Referring generally to Figures 1A through 4, the invention is denoted generally assembled as 10 (Figure 2). The wing 2 has a rear I-beam or spar 23 (see Figures 4A and 1B), spoiler 5 (Figures 3B and 1A - 1C-3) and a flap 4. Connecting the flap 4 to the rear spar 23 are two slaving mechanisms 30 and 35, respec- tively. Also connecting the flap 4 to the rear spar 23 are two swivel links 50 and 55, respectively. The linear flap actuator 60 moves the flap 4 to a rearward and downward position via swivel links 50 and 55, and the slaving mechanisms 30 and 35.

This occurs in a single motion as opposed to prior art moving the flaps rearward on tracks by one motion, and then moving the flaps downward via linkages in a second motion. The precise elements responsible for the single motion are reviewed in greater detail below.

The flap 4 is an integral component of an aircraft wing 2.

Also located on the wing 2 is the aileron 3. The aircraft wing 2 is attached to the fuselage 1 of the aircraft. Connecting the flap 4 to the wing 2 and the aileron 3 is the present inven- tion 10.

The precise component of invention 10 which interfaces with the wing 2 is the wing rear spar 23. To improve the curvature or camber when flap 4 is deployed from wing 2, the rear spar 23 is angled at its top flange at about 200 from an otherwise perpendicular position. See Figure 2.

The rear flap 4 is engaged with swivel link 50 and slaving mechanism 35 at a first flap-rib 4(a). Parallel to and spaced apart from first flap-rib 4(a) is a second flap rib 4(b) where swivel link 55 and slaving mechanism 30 engage flap 4. The flap ribs 4(a) and 4(b), at the point of engagement of their respec- tive swivel links and slaving mechanisms, are defined by a cavity (a) in flap-rib 4(a) and a cavity (b) in flap-rib 4(b) where the swivel link 50 and slaving mechanism 35 are engaged at (a) and swivel link 55 and slaving mechanism 30 are engaged at (b). In a direction perpendicular to cavities (a) and (b) on flap-ribs 4(a) and 4(b), respectively, are upper holes a1 and b1 opening into said cavities, for aligning and rotatably receiving slotted slaving-bolts 31 and 36, respectively. Immediately underneath a1 and b1 on flap-ribs 4(a) and 4(b) are lower holes a2 and b2, respectively, which also open perpendicularly into channels (a) and (b), respectively, in order to rotatably receive bolts 83 and 84 and their respective matching bushings 82 and 85.

The engagement of swivel links 50 and 55 in slots (a) and (b), respectively, is by way of flap support fittings 42 and 41, respectively. The engagement of slaving mechanisms 35 and 30 in slots (a) and (b), respectively, is by way of slot- ted slaving-bolts 31 and 36, respectively.

Linear flap actuator 60 is linearly affixed to the spar 23 at one end and flap 4 at the other end, while also partially engaging swivel link 55. Referring particularly to Figures 2 and 2A, the linear flap actuator 60 is configured to resemble a piston-type spring such as is often found on screen doors of homes. It is a piston portion and rod portion. Its piston portion is affixed to the I-beam called a wing rear spar 23 at the inner surface of the "I" by way of end bracket 62. Its rod portion extends from said piston portion and is affixed to flap 4 by a bolt 61 (not shown). Accordingly, the actuator 60 can be activated by electronic and/or hydraulic physical means to serve as the prime mover for a single motion which drives flap 4 rear- ward and downward.

Linear flap actuator 60, at its rod portion, allows swivel link 55 to hingedly swivel or pivotally engage along the axis of said rod member of actuator 60. At this pivotal attachment of swivel link 55 and actuator 60 are holes 61 to accommodate one of a plurality of bolts numbered as 58, which bolt extends vertically through said holes into an opposite set of holes 56 and a slot in said swivel link, which slot hingedly engages the 200 angled top flange of wing spar 23. The bolt 58 therefore extends through a hole in said flange and continues through the top holes 56 of the swivel link 55, as more clearly seen by combining Figures 2 and 2A. There is a rounded triangular shaped flap support fitting 41 which hingedly engages with swivel link 55 by way of engaging slots defined at holes 57 and 62 of said swivel link 55 with holes 52 and 63 of said fitting 41, through which holes another of bolts 58 extends. Nuts 59 secure bolts 58. An apex end of triangular flap support fitting 41 has an opening 64 which is aligned with b2 to receive bushings 82 and matching bolt 83 which are secured by nut 81. This apex end of support fitting 41 slides into cavity (b) of flap rib 4(b) so as to pivot up or down while rotating around the axis of bolt 83 when actuator 60 moves flap 4 rearward. Said rotation of fit- ting 41 is in intimate contact with slotted slaving bolt 36, thus limiting undue "play" in said rotation. Another bolt 58 secures the slaving arm of slaving mechanism 30 to slotted slaving bolt 36. A spherical-bearing 71 rotatably engages said slaving arm to the top flange of spar 23 at a point adjacent to the spar 23 pivotal engagement with swivel link 55. Thus, the slaving mechanism responds to either inward or outward movement of actuator 60 by a rotation action, while the swivel link 55 responds by translating its rotation into either a downward or upward pivot of support fitting 41. Slaving mechanism 35, spherical bearing 73, slotted bolt 31, support fitting 42, and swivel link 50 are similarly connected to mirror the action of their above-described corresponding mechanisms, bearings, bolts, fittings, and links, except that where swivel link 55 connects to actuator 60 at holes 61, swivel link 50 connects to a 900 angle lower flange of the I-beam or rear spar 23, and top holes 56 engage at the 200 angled top flange of spar 23 with hole 51 of said spar 23 to receive bolt 58, while hole 32 on the top flange of spar 23 accommodates spherical bearing 73 and slaving mechanism 35, where spar 23 top flange hole 37 accommo- dated slaving mechanism 30.

The use of spherical bearings 73 and 71 allows the slaving mechanisms 35 and 30 to rotate even though misaligned at their points engagement with spar 23, as opposed to a regular hinge which would not operate if misaligned at engagement. Also, the amount of camber may be controlled by altering the displacement length of the flap actuator 60. The use of linear flap actua- tor 60 having a piston-like action allows for a faster response than do conventional gear and motor systems.

Figures 4A and 4B illustrate the cooperative motion of swivel links 50 and 55 with slaving mechanisms 30 and 35 in relation to the deployment of flap 4. The flap actuator 60 is not shown in order to afford clarity in viewing and discussing the interaction between the swivel links and the slaving mecha- nisms with the flap. Swivel links 50 and 55 and slaving mecha- nisms 35 and 30 are viewed overhead together with the flap 4 in Figures 4A and 4B. The flap 4 and one of said links and said slaving mechanism are viewed from the side in Figure 4B-1.

In Figure 4A, flap 4 is in the stowed position, which is roughly level with the wing, and the swivel links 50 and 55 are parallel to the face of rear spar 23. The slaving mechanisms 30 and 35 are positioned at an angle other than parallel.

In Figure 4B, the flap 4 is partially deployed and the swivel links 50 and 55 and slaving mechanisms 30 and 35 have rotated outward from the face of spar 23. Note that flap 4 has started to separate from the wing spar 23 and, as can be seen in corresponding Figure 3B, the trailing edge 6 has moved downward.

Now viewing Figure 3B, it is possible to observe the entire curvature of the wing 2 and deployed flap rib 4(a). The air- flow 7 is capable of passing over and under the wing 2 and deployed flap rib 4(a) without disruption. When this flow is compared to the airflow of the prior art 102 on Figure 5b, the advantages of the present invention can be seen to be smoother and with less interference.

This device may also be used for a leading edge flap by merely reversing the flap 4 position to the leading edge for a forward spar.

It will be obvious to those skilled in the art that various changes may be made without departing from the scope of the invention and the invention is not to be considered limited to what is illustrated in the drawings and described in the specifi- cation. For instance, the slaving link may be positioned on the under surface of the flap and flap support fitting 4 and mounting hole 64 moved to the upper region of the flap.