US3570767A

US3570767A - Thrust reversing apparatus

Info

Publication number: US3570767A
Application number: US862725A
Authority: US
Inventors: Dale W R Lawson; Felix Hom; Richard U Moeller
Original assignee: Rohr Inc
Current assignee: Rohr Inc
Priority date: 1969-10-01
Filing date: 1969-10-01
Publication date: 1971-03-16
Anticipated expiration: 1988-03-16

Abstract

Apparatus includes housing to rear of jet nozzle to surround the gas stream. Housing has openings in wall to receive thrust reverser doors which close openings in stowed position and swing to deployed thrust reverse position with trailing edges together. Doors diverge forwardly and leading edges are adjacent housing wall. Doors are curved about longitudinal axis and have end plates at leading edges to divert gas stream forwardly. Each end plate is divided into segments along leading edge pivoted thereto for swinging from parallel to perpendicular position. Segments are overlapped to move as a unit while accommodating curvature of door. In one form, segments are forced to open position by gas flow and returned to stowed position by bumper when doors close. In an another form, yoke within door actuated by movement of doors acts through force linkage to positively swing segments in each direction.

Description

United States Patent [72] Inventors Dale W. R. Lawson Bonita; Felix Horn, La Mesa; Richard U. Moeller, El Cajon, Calif. [21] Appl. No. 862,725 [22 Filed Oct. 1,1969 [45] Patented Mar.l6,1971 [73] Assignee Rohr Corporation Chula Vista, Calif.

[54] THRUST REVERSING APPARATUS 15 Claims, 13 Drawing Figs.

[52] US. Cl ..239/265.29, 239/265 .31 [51] Int. Cl B64c 15/04 [50] Field of Search ..239/265.29, 265.27, 265.31; 60/229, 230

[ 5 6] References Cited UNITED STATES PATENTS 3,024,601 3/1962 Nash 239/265.29X

3,280,561 10/1966 Kutney 3,483,702 12/1969 Ward Primary Examiner-M. Henson Wood, Jr. Assistant Examiner-John J. Love Attorney-George E. Pearson trailing edges together. Doors diverge forwardly and leading edges are adjacent housing wall. Doors are curved about longitudinal axis and have end plates at leading edges to divert gas stream forwardly. Each end plate is divided into segments along leading edge pivoted thereto for swinging from parallel to perpendicular position. Segments are overlapped to move as a unit while accommodating curvature of door. In one form, segments are forced to open position by gas flow and returned to stowed position by bumper when doors close. In an another form, yoke within door actuated by movement of doors acts through force linkage to positively swing segments in each direction.

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sum .5 or 5 INVENTOR- DALE W. R. LAWSON FELIX HOM RICHARD u. M ELLER BY EMA) ATTORNE THRUST REVERSING APPARATUS BACKGROUND OF THE INVENTION This invention lies in the field of gas turbine engines, more commonly called jet engines, which produce reaction thrust by ejecting a high-velocity stream of gas from the exhaust nozzle of the gas turbine. Airplanes driven by jet engines fly and land at much higher speeds than propeller-driven aircraft. Their high landing speed puts a great burden on the wheel brakes and of course they do not have propellers which are readily reversible to produce reverse thrust. Therefore, it is necessary to provide apparatus to reverse the gas stream to accomplish this result.

Various types of thrust reversers have been in use for many years. All of them utilize a basic principle of blocking the rearward flow of the exhaust gas stream and diverting it laterally. If the stream has no forward component it will act in the manner of a speed brake by interference with the free airstream, which is relatively ineffective. Normally, however, the stream is directed substantially forwardly to produce an actual reverse thrust. A common type of thrust reverser has lateral openings in the wall of the nozzle or a housing in extension of the nozzle with deflector doors in the openings which close them in stowed position. For reverse thrust the doors are swung inwardly and rearwardly with their trailing edges meeting at the center of the housing to blockrearward flow, and the doors diverge forwardly to guide the exhaust gases outwardly and forwardly.

A drawback of this general type of reverser is that, since the trailing edges must meet at the center, short doors must swing so far that they have very little forward component. If a substantial forward angle is to be achieved with the leading edges as far outside the housing wall as desired, the doors must be unreasonably long. One answer to this problem has been the provision of deflector plates mounted on the inner wall of each reverser door pivoted to swing to deflecting position as the door is deployed. The plates must be curved to lie flat on the inner faces of the doors in stowed position and their form makes them only partially effective in active position. Moreover, they prevent smooth streamlining of the door inner wall for cruising flight where there is a requirement for clearance and for ejector nozzle configurations.

Another answer is an end plate at the extreme leading edge of each door substantially perpendicular to the door surface. It has been found that a fixed end plate standing only a few inches high at the leading edge is very effective. It appears that the abrupt diversion of gas has the effect of producing a virtual wall much higher than an aerodynamically shaped end plate of the same actual height. The difficulty with this construction is that even these small end plates will project inward during normal cruising flight and, in many applications, will interfere with efficient operation.

SUMMARY OF THE INVENTION The present invention preserves the advantages mentioned above while eliminating the problems which make the prior devices unsatisfactory. Generally stated, the apparatus includes a housing which may be the nozzle or tailpipe or an additional housing in continuation thereof, which receives and directs the exhaust gas stream. Openings in the wall of the housing are provided with doors which in stowed position close the openings and in deployed position swing back and inward so that their trailing edges meet at the center of the housing to block rearward flow of the gas stream and direct it laterally through the openings. End plates are provided at the leading edges of the doors.

In all forms of the invention each end plate is made up of a plurality of segments which are individually pivotally mounted but which are overlapped so that they move as a unit. In practically all cases the reverser doors are laterally curved about a longitudinal axis to complete the contour of a generally cylindrical housing. If a unitary end plate is used, it must be curved to match the curvature of the door when stowed. This makes it difficult to mount and in addition it is much less effective in use. The segmental construction of the present end plates provides for a very satisfactory transition from a curved form in stowed position to a planar form in deployed position.

In one form of the invention, a yoke is mounted between the spaced inner andouter walls of the door adjacent its leading edge, and is moved a short distance fore and aft by actuating links connected to the housing. A plurality of force linkages connect the yoke to some of the. pivoted segments so that movement of the yoke causes all of thesegments, because of the overlapping arrangement, to swing between stowed and deployed positions. When stowed, the segments extend forward from the leading edge of the door in streamline continuation to form a leading edge lip and complete the closure of the housing opening.

In a modified form, the pivoted segments extend rearwardly of their pivotal mountings and lie on the inner wall of the door when they are in stowed position. They are freely pivoted so that when the door opens; the gas stream passing forwardly swings the segments to their perpendicular position where they are retained against further outward movement by suitable abutments. Bumper means are carried by the housing at the forward ends of the openings to intercept the segments shortly before the doors are completely closed. The relative movement of the doors is such that the bumper means urge the segments rearward into their stowed positions.

While the invention is primarily intended for use in the construction described, it will be apparent that it can be applied equally well to the external target-type reversers in which the doors swing to a reversing position spaced behind the nozzle or other housing.

BRIEF DESCRIPTION OF THE DRAWINGS Various other advantages and features of novelty will become apparent as the description proceeds in conjunction with the accompanying drawings, in which:

FIG. 1 is a schematic perspective view of a housing with the reverser doors in stowed position;

FIG. 2 is a similar view showing the doors in deployed position;

FIG. 3 is a schematic side elevational view, partly in section, showing a first form of the invention;

FIGS. 4 and 5 are sectional views taken at different points on one of a plurality of vanes mounted on the doors, the vane being illustrated in stowed position;

FIG. 6 is a view taken on line 6-6 of FIG. 3;

FIG. 7 is a schematic side elevational view, partly in section, showing the door and end plate segments of FIG. 3 in deployed position;

FIG. 8 is a schematic side elevational view of a second form of the invention, with the door in stowed position;

FIG. 9 is a view similar to FIG. 8, with the door in deployed position;

FIG. 10 is a schematic side elevational view, partly in section, showing a third form of the invention, with the door approaching stowed position;

FIG. 11 is a view similar to FIG. 10, with an end plate segment contacting the bumper means;

FIG. 12 is a view similar to FIG. 10, showing the segments partially folded; and

FIG. 13 is a view similar to FIG. 10, showing the segments fully stowed.

DESCRIPTION OF PREFERRED EMBODIMENTS The apparatus of this invention may be used with any general type of engine installation, such as pod, wing, or fuselage mounting. For convenience of illustration it is shown schematically in FIGS. 1 and 2 as including a housing 10 provided with reverser doors 12, the housing being mounted as a continuation of the tail pipe or nozzle 14 of an engine not shown.

In FIG. I, the doors are shown in closed or stowed position with the end plates 16 parallel to the doors and extending forward to complete the closure of openings 18 in the housing. In FIG. 2 the doors are shown in open or deployed position with the end plates 16 extending inward and forward generally perpendicular to the inner walls of the doors. The trailing edges 20 of the doors meet substantially at the center of the housing to block the rearward flow of the exhaust stream and direct it laterally and forwardly through the openings 18 to produce reverse thrust.

As can be seen in FIG. 2, the doors themselves may have little or no forward component, extending at an angle of about 75 to 100 to the housing axis. The major part or all of the thrust reversal is accomplished by the provision of the end plates 16. The abrupt abutment presented by the provision of the end plates 16. The abrupt abutment presented by each end plate very forcefully diverts the gas stream forwardly to produce a very high reverse thrust component. With a plate height of to percent of a nozzle diameter, reverse thrust has been developed amounting to as much as 60 percent of the full forward thrust of the engine.

One detailed form of the invention is shown in FIGS. 3 to 7, which also show in broken lines a suitable mechanism, not a part of the present invention, for moving the doors of any of the forms between stowed and deployed positions. Briefly, each door 12 is provided at each of its longitudinally extending lateral margins 22 with a pivotal connection 24 to the wall of the housing for swinging about a lateral axis perpendicular to the axis of the housing. When the door is deployed as seen in FIG. 7, its leading edge 26 is adjacent the wall of the housing and its trailing edge is generally at the center of the housing, cooperating with the other door or doors to block rearward flow of the gas stream and direct it laterally. End plates 16 then redirect the stream forwardly almost parallel to the axis of the housing.

A crank arm 28 is fixedly connected to the door at pivotal mounting 24 and in the stowed position of said door extends rearwardly as seen in FIG. 3. Its free end is pivotally connected at 30 to a link 32 which in turn is pivotally connected to bogie 34 slidably mounted on tracks 36. The bogie is actuated by a servomotor, not shown, and moves forward to swing the door to deployed position and moves rearward to swing the door to stowed position. i

It will be noted that each door 12 is laterally curved about a longitudinal axis such as the axis of the housing. If a unitary end plate were used, it would necessarily have the curvature of the door and it would be difficult if not impossible to shape it and mount it so that it would provide a uniform abutment in action and be rigidly held against the high gas stream forces. The present construction overcomes this difficulty by the use of a plurality of end plate segments individually pivotally mounted to the leading edge of the door and of substantially the same dimensions. Although each segment is almost flat, the total assembly closely follows the door contour.

All of the segments are hollow and have triangular cross sections. The segments 38 are larger than the segments 40 and the latter fit slidably in the former to produce an overlapping assembly which moves as a unit. Each segment has at least one and preferably two pivotal mountings at the leading edge of the door adjacent its inner wall 42. A typical mounting is bracket 44, FIG. 5, having a pivot pin 46 on which segment 38 swings. In most cases, each segment is carried by two of these brackets. In FIG. 4, the support is in the form of a rail or guide track 48 which serves another purpose to be described later. Track 48 is rigidly mounted in the door and at its forward end is provided with a pivot pin 50 on which segment 38 swings.

Force applying means to case segment 38 to swing between stowed and deployed positions is seen in FIG. 4 as a force link 52 which is axially slidable and is provided at its forward end with a pivot pin 54 for connection to the outer rear edge of segment 38 close to the outer wall 56 of the door. Forward movement of force link 52, to the left as seen in FIG. 4, forces segment 38 to swing clockwise to a deployed position generally perpendicular to inner wall 42 of the door, and rearward movement of the force link causes the segment to return to stowed position extending forwardly of its pivotal mounting in general streamline continuation of the door. A force link may be applied to all or only some of the segments 38. In any event, enough links are used to ensure uniform operation. Since all of

segments

38 and 40 are overlapped as described, the free swing segments will necessarily move with the driven segments, and the entire end plate assembly will gradually change from arcuate to planar form as it deploys.

As will be seen in FIGS. 3, 6, and 7, a plurality of guide tracks 48 are spaced evenly across the lateral extent of the door and serve to support the force transmitting means which moves the force links 52. The force transmitting means comprises a rigid elongate bar 58 extending laterally between the inner and outer walls of the door from margin to margin and curved to conform to the curvature of the door and form a yoke. The yoke is provided with a bearing 60 for slidable mounting on each guide track 48 as best seen in FIG. 6. Each bearing includes a bracket 62 having a pivot pin 64 to which is connected the aft end of one of the force links 52. Thus, the fore and aft sliding movement of the yoke causes a corresponding fore and aft movement of all of the force links and the swinging of all of the segments.

Force initiating means are provided to produce the necessary fore and aft sliding movement of the yoke. One such mechanism is located at each lateral margin of the door. Since they are alike in form and action, only one will be described. Referring to FIGS. 3 and 6, an actuating link 66 is connected at its forward end within the door to an end of yoke 58 and is also slidably mounted in the door by means of a pin 68 which rides in a slot 70 (FIG. 7) in support guide 72 which is fixedly mounted in the door. The aft end of link 66 is pivotally connected to anchor pin 74 which is fixedly mounted in the housing adjacent the door margin and is offset downwardly, as seen in FIG. 3, from the pivotal mounting 24 of the door. As the door swings from the FIG. 3 position to the FIG. 7 position, the forward end of link 66 moves forward with respect to the door and moves yoke 58 forward to the same extent. The forward movement of the yoke causes deployment of the segments as previously described in their FIG. 7 positions.

A modified force linkage is illustrated in FIGS. 8 and 9 for use in cases where the gas stream force on the end plates is very high. In this form the force initiating means and force transmitting means are the same as in the first form, and the end plate segments are formed, arranged, and pivotally mounted in the same way. Force links 52 are replaced by elongate cam members 76, each of which is fixedly connected at its aft end to a bracket 62 on the yoke. The forward end is provided with a cam face 78 angling inwardly and rearwardly. In the stowed position the cam face is in contact with the outer rear comer 80 of the end plate segment, as seen in FIG. 8.

When the yoke moves the cam member forwardly, cam face 78 forces corner 80 forward and inward to the FIG. 9 position, and the body of the cam member underlies the segment and positively prevents its return to the FIG. 8 position. Rearward movement of the cam member allows the segment to swing to stowed position. However, it cannot positively pull the segment back and hold it. For this purpose, tie link 82 is provided and is pivotally connected at its aft end to cam member 76 by pin 84. The tie link is provided with an elongate slot 86 which has a lost-motion connection with pin 88 on the segment. Thus the tie link does not interfere with the deploying movement. However, as the cam member returns to stowed position, pin 88 reaches the end of slot 86 and the tie link positively pulls the segment to stowed position and holds it against movement.

A further modified form of the invention is shown in FIGS. 10 to 13 in which the end plate segments in stowed position extend rearwardly from their pivotal mountings to lie along the inner wall 42 of the door 12 and substantially parallel thereto. In this case the segments may be in the form of

single thickness plates

90 and 92 which may be arranged in alternately overlapping relation. Each segment is pivotally mounted by pin 94 to a bracket 96 secured to the leading edge of the door and is free swinging. FIG. illustrates a door in the deployed position, at which time the end plate segments are substantially perpendicular to inner wall 42 of the door. A corner or abutment 98 at the pivot edge of each segment engages the associated bracket 96 to prevent further forward movement of the segment relative to the door.

Bumper means are provided in the form of an inwardly angled strip 100 which is secured to the inner wall of housing 10 and extends laterally for the full width of opening 18 in the housing and also extends a short distance rearwardly of the forward edge 102 of the opening l8. As the door is being deployed and reaches the position illustrated in FIG. 11, the

segments

90 and 92 disengage from strip 100 and then the pressure of the exhaust stream impinging upon the aft sides of said segments swings the latter to the position illustrated in FIG. W. The strip 100 is so dimensioned and positioned that, as the leading edge of the door moves toward stowed position along path 104, the free edges 106 of. the segments 90 will contact the free edge 108 of the strip 100 as seen in FIG. 11. As closing is completed through FIGS. 12 and 13, the bumper strip gradually causes the segments to fold down into stowed position substantially parallel with the inner wall 42 of the door R2. The gap between the housing wall and the bumper strip receives the leading edge of the door so that a smooth streamlined contour is achieved for normal cruising flight.

We claim:

1. Thrust reversing apparatus for use in combination with a jet engine and adapted to be mounted aft of the exhaust outlet for controlling the flow of exhaust gas therefrom, comprising: an open-ended housing to receive and direct the exhaust gas flow; openings in the sidewall of the housing; a thrust reverser door mounted in each opening and swingable between a stowed position closing said opening and a deployed position in which the trailing edges cooperate to block rearward axial flow through the housing and each door extends outwardly and forwardly from the center of the housing with its leading edge adjacent to the housing wall; the leading edge of each door comprising a plurality of end plate segments arranged laterally adjacent to each other in overlapping relation to form a substantially continuous leading edge lip; said segments being pivotally mounted at said leading edge and swingable between stowed positions lying generally parallel to the door and deployed positions extending inward of the door and generally perpendicular thereto; and means acting in response to movement of the door to stowed position to cause said segments to move to their stowed positions.

2. apparatus as claimed in claim 1, said segments in their stowed positions extending rearwardly of their pivotal mountings along the inner wall of the door and being freely mounted to be swung to their deployed positions by the force of the exhaust gas flow against them.

3. Apparatus as claimed in claim 2; said means comprising bumper means fixedly mounted at the leading edge of the opening in the housing and position to contact the free edges of of at least some of the segments and cause the segments to swing rearwardly to a position of substantial parallelism with the inner wall of the door.

4. Apparatus as claimed in claim 3; said bumper means comprisinga generally continuous strip fixedly secured to the inner wall of the housing and extending rearwardly of the leading edge of the opening to intercept the free edges of the segments as the door approaches fully stowed position.

5. Apparatus as claimed in claim 1; said segments in their stowed positions extending forwardly of their pivotal mountings and constituting a forward streamlined continuation of the door to form a complete closure for the housing opening.

6. Apparatus as claimed in claim 5; said door having inner and outer spaced walls; and said means to cause said segments to move to stowed position being constructed to also cause said segments to move to deployed position; said segment moving means being mounted within said door between its inner a outer walls.

7. Apparatus as claim 6; said segment moving means including force initiating means movable in response to swinging movement of said door, force transmitting means connected to said force initiating means and movable thereby, and force applying means connected between said force transmitting means and at least some of said segments and movable to swing aid segments between stowed and deployed positions.

8. Apparatus as claimed in claim 7; said door having lateral margins extending in a fore and aft direction; an anchor pivot mounted in the housing adjacent to each of said margins and offset from the effective axis of rotation of the door; a support guide mounted at each margin of the door adjacent to its leading edge; and said force initiating means comprising an actuating link extending in a fore and aft direction at each margin of the door and having a first end pivotally connected to said anchor pivot and a second end movably connected to said support guide.

9. Apparatus as claimed in claim 7; said door having lateral margins extending in a fore and aft direction; a plurality of guide tracks within the door adjacent to its leading edge and laterally spaced between the margins and extending parallel to each other in a fore and aft direction; and said force transmitting means comprising a rigid elongate bar extending laterally substantially from margin to margin adjacent to the leading edge; said bar having bearing members slidably mounted on said guide tracks to provide fore and aft movement of said bar.

10. Apparatus as claimed in claim 9; said door being laterally curved about a longitudinal axis and said bar being correspondingly curved to form a yoke.

11. 1. Apparatus as claimed in claim 7; said door having lateral margins extending in a fore and aft direction; segment support pivots secured to the leading edge of the door adjacent to the inner wall thereof and arranged in spaced relation from margin to margin, with at least one pivot for each segment; said segments being mounted on said pivots 'for swinging inwardly from stowed streamlined position to deployed position generally perpendicular to the inner wall of the door; and said force applying means comprising a plurality of force linkages arranged in spaced relation along the leading edge of the door from margin to margin, connected at their aft ends to said force transmitting means and at their forward ends to outer portions of adjacent segments; said linkages being movable forwardly to deploysaid segments and rearwardly to stow said segments.

12. Apparatus as claimed in claim 11; the linkage-driven segments acting through their overlapping relation to swing those segments which are not connected to the linkages.

l3. apparatus as claimed in claim 11; each of said force linkages comprising an elongate link pivotally connected at its aft end to the force transmitting means and pivotally connected at its forward end to one of said segments. v

14. Apparatus as claimed in claim 11; each of said force linkages comprising an elongate cam member connected at its aft end to the force transmitting means and having a cam face at its forward end to engage the outer rear edge of the adjacent segment and movable forwardly to force the segment to rotate inward to deployed position and underlie the segment to prevent its return to stowed position; and a tie link pivotally connected to said segment and said cam member and incorporating lost motion; rearward movement of said cam member removing the cam face from blocking position and drawing the tie link rearwardly to positively return the segment to fully stowed position.

15. Apparatus as claimed in claim 6; said door being laterally curved about a longitudinal axis and having lateral margins extending in a fore and aft direction; said segment moving means comprising an actuating link pivotally connected at a first end to the housing at a point offset from the effective axis of rotation of the door and slidably connected at its second end to the door; a curved yoke within the door adjacent to the leading edge thereof and slidably mounted therein for fore and aft movement; said yoke extending substantially from margin to margin of the door and having one aft movement; and force linkages connected between said yoke and a plurality of said segments to swing them between stowed and deployed positions in response to the fore and aft movement ofthe yoke.

Claims

4. Apparatus as claimed in claim 3; said bumper means comprising a generally continuous strip fixedly secured to the inner wall of the housing and extending rearwardly of the leading edge of the opening to intercept the free edges of the segments as the door approaches fully stowed position.

11. 1. Apparatus as claimed in claim 7; said door having lateral margIns extending in a fore and aft direction; segment support pivots secured to the leading edge of the door adjacent to the inner wall thereof and arranged in spaced relation from margin to margin, with at least one pivot for each segment; said segments being mounted on said pivots for swinging inwardly from stowed streamlined position to deployed position generally perpendicular to the inner wall of the door; and said force applying means comprising a plurality of force linkages arranged in spaced relation along the leading edge of the door from margin to margin, connected at their aft ends to said force transmitting means and at their forward ends to outer portions of adjacent segments; said linkages being movable forwardly to deploy said segments and rearwardly to stow said segments.

13. apparatus as claimed in claim 11; each of said force linkages comprising an elongate link pivotally connected at its aft end to the force transmitting means and pivotally connected at its forward end to one of said segments.

15. Apparatus as claimed in claim 6; said door being laterally curved about a longitudinal axis and having lateral margins extending in a fore and aft direction; said segment moving means comprising an actuating link pivotally connected at a first end to the housing at a point offset from the effective axis of rotation of the door and slidably connected at its second end to the door; a curved yoke within the door adjacent to the leading edge thereof and slidably mounted therein for fore and aft movement; said yoke extending substantially from margin to margin of the door and having one end connected to said actuating link to produce said fore and aft movement; and force linkages connected between said yoke and a plurality of said segments to swing them between stowed and deployed positions in response to the fore and aft movement of the yoke.