DE2057335A1 - Device for retracting and extending the landing gear of aircraft - Google Patents

Description

Patent application Automotive Products Company limited, Tachbrook Road,

Leamington Spa, Warwickshire; England

Device for extending and retracting the landing gear of aircraft

The invention relates to a device with which the landing gear of an aircraft can be retracted and extended, consisting of a bracket with a rotatable part, which is firmly connected to an airframe, from a retractable chassis leg attached to the rotatable part about an axis perpendicular to the axis of rotation of the rotatable part or runs parallel to such an axis, is pivotably articulated, and from a retraction cylinder of two along an axis mutually movable parts.

The landing gear of an aircraft is generally retracted and extended in such a way that within a range of Movement steps one after the other a swivel movement of the chassis leg once by one in relation to the airframe, with which the chassis is firmly connected, horizontal and the other time around a vertical axis.

109836/0162

Postal checking account Essen 47247 · Commerzbank AG, Düsseldorf, DeposRenkasee main station

A retractable cylinder can be attached to a plug-in unit in be articulated in such a way that it is pivotable about a horizontal axis with respect to the plug stuff cell, the Actuator of this retraction cylinder, which is in the axial Direction in the housing of the main body of the retractable cylinder is movable, so with the chassis leg of the plug stuff is connected that it can pivot this about a horizontal axis with respect to the plug stuff cell. As can be seen, a complicated articulation is necessary to allow the axial movement of the actuator to transform into such an actuation movement that the chassis leg a pivoting movement about one in relation to to issue the plug stuff cell vertical axis. It can therefore be used to achieve such a pivoting movement of the chassis leg another retraction cylinder can be provided.

The object of the present invention is to provide a device for extending and retracting the chassis of a plug-in tool to create, with the help of only one retraction cylinder, the chassis leg a successive pivoting movement about one horizontal and one vertical in relation to the plug-in unit to which the chassis is firmly connected Axis made possible without a complicated articulated connection or further retraction cylinders being provided for this purpose have to.

According to the invention this object is achieved in that a first part of the retraction cylinder for connection to the Plugzeugzelle is formed via a universal joint that a second part of the retraction cylinder by means of a

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Universal joint connected to the chassis leg and "at the mutual movement of the two parts mentioned can be moved together with the chassis leg, that the chassis leg is lockable against a pivoting movement relative to the rotatable part, and that the rotatable part for Cooperation with a Peststelleinrichtung is set up, with a rotational movement of the rotatable part against the airframe is normally not possible and only when the landing gear leg is locked against pivoting movement is released relative to the rotatable part.

It is expedient in the device according to the invention the rotatable part is rotatably mounted on a carrier fixedly connected to the plug-in cell, the carrier has a pest control device arranged to cooperate with the rotatable part. The plague facility exists from a pin which is arranged to cooperate with a hole in the rotatable part and engages the hole under the action of spring pressure.

In the device according to the invention, the pin is expediently movable with a cylinder Piston connected, the pin out of engagement with the hole by means of an exerted on the piston in the cylinder Pressure medium pressure is releasable.

In the device according to the invention there is a locking device consisting of a lever and a rod provided, wherein the rod is designed for fitting into a recess of the lever and when the engagement of the

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Rod in the recess of the chassis leg against a Movement is locked relative to the rotatable part. The lever is attached to the rotatable part and the rod is connected to the chassis leg; the lever is under spring load with an upwardly open recess on the fastening device firmly connected to the airframe arranged. The lever has on the end part remote from the spring on its outside a convex, from the upwardly open recess on the downward curvature and is in a pivoting movement of the chassis leg against the rotatable part by means of the rod against the pressure of the spring for engagement of the rod movable into the recess.

In the device according to the invention, the hole of the locking device is expediently in a radial flange of the rotatable part and after connecting the fastening device to the airframe directly above of the lever, wherein the pin can be pressed through the hole against the upper surface of the lever and the lever by pressing the pin against the spring load releasing the in the upwardly open recess held rod is movable.

In the device according to the invention, said first part of the retraction cylinder is for connection to the Airframe formed via a coupling device.

According to the invention, in a device for retracting and extending the landing gear of an aircraft, which consists of a Attachment device to the airframe with a

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rotatable part for rotation around a perpendicular to the plug stuff cell extending axis, from a hinged to the rotatable part and pivotable about a horizontal axis Chassis leg and a retraction cylinder with two parts that can move relative to one another along an axis consists, a first part of the retraction cylinder via a universal joint to the airframe and a second part of the retraction cylinder via a universal joint with the Chassis leg connected, the chassis leg against pivoting movement relative to the rotatable part can be locked and the rotatable part is designed to interact with a locking device on the airframe is. A rotary movement of the rotatable part against the airframe is normally not possible and only released when the chassis leg is locked against a pivoting movement relative to the rotatable part.

In the following an embodiment of the invention is described with reference to figures:

Figure 1 shows the side view of a aircraft equipped with the device according to the invention.

FIG. 2 shows, in an enlarged illustration, a partial view from FIG. 1 with a main landing gear according to the invention.

Figure 3 shows the front view of the invention Chassis from the viewing direction of arrow A in FIG. 2.

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Figure 4 shows the arrangements according to
Figures 2 and 3 in plan.

Figure 5 shows in an enlarged view
a block drawing of a part
the device according to the invention
in the case of an aircraft landing gear
Figures 2, 3 and 4 <

•O

FIG. 1 shows an aircraft standing with its retractable landing gear on the ground 7. The landing gear consists of
a nose wheel 8 and two main wheels 9, only one of which can be seen in FIG. which can be closed by a door 10 during normal flight operations, can be withdrawn. Each of the main wheels 9 is connected to a retractable chassis ^{leg Λ} Α of the chassis unit 12 · This chassis unit 12 is arranged so that the chassis leg 11 by a pivoting movement that is directed upwards and outwards
can be withdrawn to a central position,
from where it can be completely drawn into a space 15 by a forward pivoting movement, which is located in a cell of the aircraft fuselage 16 below the wings »

Figures 2 to 4 show the chassis 12 of the main wheels in the division of operations with solid lines and in the intermediate position 13, and in the fully retracted position 14 with broken lines _{or the like}

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The aircraft landing gear 12 consists of a carrier 17 which is firmly connected to the airframe 16, and from a rotatable support arm 18 which is connected to the carrier 17 and is rotatable about an axis perpendicular to the plug-in tool cell 16. The chassis leg 11 is on one End 19 hinged to the rotatable support arm 18, the pivot axis running horizontally, and carries on its other End of the main wheel 9. The retraction cylinder 20 is with the free end of its actuating member 21 via a universal joint 22 which runs along the length of the chassis leg is arranged closer to the joint 19 than to the axis of the wheel 9, connected to the chassis leg 11. The chassis leg 11 and the retraction cylinder 20 are known in terms of their general structure and mode of operation Manner and do not form part of the present invention.

The end 23 of the main body of the retraction cylinder 20, which is remote from the universal joint 22, is via a Coupling device (not shown) connected to the airframe 16, including a universal joint. As Figures 2, 3 and 4 show, the axis of the retraction cylinder 20 forms an acute angle with both the Center line X-X of the aircraft as well as the main axis of the aircraft and the horizontal plane in which is the chassis leg 11 in its operating position, the solid lines in FIGS. 2, 3 and 4 Lines is shown.

The chassis leg 11 has a protruding part 24, which extends upwards and outside the center line X-X of the part of the leg closer to the joint 19

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extends and consists of two parallel tongues, which are held at a distance from one another by a connecting rod 25 near the extreme end of the protruding part 24 will.

The rotatable support arm 18 has on its upper side (see FIGS. 2, 3, 5) a flange 26 with an opening 27 extending through the top and bottom surfaces of this flange 26. A lever 28 is on the rotatable Support arm 18 attached and pivotable about a horizontal axis of rotation at pivot point 29. The lever 28 is (see Figure 5) loaded with the pressure of a spring 30 and is thereby brought into such a position that the with respect to the Support point 29 on the opposite side of the lever 28 at a short distance from the lower surface of the flange 26 is held. Near the end of the lever 28 remote from the spring 30 is an upwardly open one The recess 31 »of this end of the lever 28 is convex Curvature which is directed outward and from the upwardly open recess 31 downward. The lever is arranged directly below the opening 27 and carries a (not shown) microswitch, the actuator of which cooperates with the flange 26 and one part represents the control device through which the retraction cylinder 20 is supplied with pressure medium for its actuation will. The actuator of the microswitch comes into engagement with the flange 26 when the lever 28 reached its position determined by the spring load.

The carrier 17 has a locking device which is arranged so that a rotary movement of the rotatable support

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poor 18 with respect to the plug stuff cell 16 is prevented This locking device consists of a stop 32, which rotates the rotatable support arm 18 counterclockwise (See FIG. 4) beyond a position which the rotatable support arm assumes in the operating position of the chassis leg 11. A (not shown) Microswitch is connected to stop 32 in such a way that that its actuating member is actuated by the installation and storage of the rotatable support arm 18.

Further details of the locking device are shown in Figure 5; thereafter a piston 33 is in a vertical position Direction movable in a cylinder 34 and carries a downwardly projecting pin 35, which is normally extends through the lower end wall of the cylinder 34 into the opening 27. By the piston 33 and the pin 35 an annular cylinder space 36 is determined within the cylinder 34. On the inner wall of the cylinder 34, namely near the upper end wall of this cylinder, there are stops 37. By the upper piston 39 and the upper end wall of the cylinder 34 another cylinder space 38 is determined. Between the lower surface of the upper piston 39 and the upper Area of an annular flange extending outward in the radial direction, which is located at the end closer to the piston 33 of the cylindrical main part of a tubular spring support 41 is located, a compression spring 40 acts. At the other end of the spring support 41 there is an annular flange extending inward in the radial direction, which is coaxial with the downwardly protruding part 42 of the upper piston 39, which is itself coaxial with the piston 39

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extends, is arranged and surrounds this, wherein this annular flange is arranged so that it is in engagement with the upper annular surface of a flange 43 extending outward in the radial direction, which is located on the lower End of the piston part 42 is arranged.

An inlet 44 connects the annular cylinder space 36 to a source of pressure medium. The middle part of the cylinder space between the two pistons 33 and 39 is connected through an inlet 45 to a pressure medium source, while the cylinder space 38 is connected through the inlet 46 to a further pressure medium source. A (not shown) Microswitch is arranged to indicate when the pin 35 is out of engagement with it the opening 27 is released.

The microswitch located on the stop 32 is part of a control device that automatically controls the Supply of pressure medium to the cylinder 34 through the two inlets 44 and 45 controls. The operation of this microswitch takes place first by the installation of its actuator on the rotatable support arm 18 and causes is supplied by the control device through the inlet 45 pressure medium. The operation of the microswitch cause by detachment of the actuator from the rotatable support arm 18 that by the control device the supply of pressure medium through the inlet 44 is interrupted. The supply of pressure medium through the inlet 46 into the cylinder space 38 takes place by means of a separate control device which can only be actuated in an emergency.

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In the operating position of the aircraft landing gear 12, the leg 11 is in the position shown with solid lines Position of Figures 2, 3 and 4 and is held in this position by the retraction cylinder 20, its Actuator 21 is then retained in a position in which it is fully inserted into the main body of the retraction cylinder 20 is withdrawn. There is then an equilibrium of the pressure medium pressures on the opposite one Areas of the pistons 33 and 39 act. The piston 33 is in a position in which the Pin 35 through the opening 27 of the flange 26 on the "

rotatable support arm 18 engages through it, while the upper piston 39 under the action of the spring 40 the stops 37 is present. In this way, the rotatable support arm is able to rotate about one with respect to the carrier vertical axis prevented.

To retract the chassis leg 11, the retraction cylinder 20 pressure medium is supplied so that the actuator 21 is released from its detection and is moved in the axial direction relative to the main part of the retraction cylinder 20 moves-, whereby the distance between the joints 22 and 23 is increased. In this way, J

the chassis leg 11 around the horizontal pivot axle pivoted upwards. By this movement, the rod 25 of the protruding member 24 is in contact with the brought convex curved surface of the end of the lever 28. As a result, the lever 28 is counteracted by the force of the spring 30 pivoted by means of the rod 25 until this rod 25 engages in the upwardly open recess 31, after which the lever 28 under the action of the spring 30 of the

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Movement of the rod 25 along with the movement of the chassis leg follows until the intermediate position 13 is reached. In this intermediate position 13, the rod 25 is in the upwardly open recess 31 supported so that the Chassis leg 11 is locked to the rotatable support arm 18; the microswitch arranged on the lever 28 becomes then actuated by abutment of its actuating member on the flat 26. As can be seen, achieved at the same time with the locking of the chassis leg 11 with the rotatable support arm 18 of the retraction cylinder 20 a completely extended position.

The operation of the microswitch on the lever 28 has to Result that the chassis leg 11 from the intermediate position 13 is moved into the fully sucked in position 15. this happens in that pressure medium is fed into the annular cylinder space through the inlet 44, so that the piston 33 moves against the force of the spring 40 together with the pin 35 upwards. If the pin 35 is off the engagement of the opening 27 released, the corresponding microswitch is actuated, whereby a rotation of the rotatable support arm 18 is made possible about a vertical axis with respect to the carrier 17. This is done by that actuation of the microswitch triggers the supply of hydraulic fluid to the retraction cylinder, whereby the actuator 21 is again fully retracted with respect to the main body of the retraction cylinder 20 Position is brought.

This movement of the actuator 21 causes a rotation of the chassis leg 11 together with the rotatable support

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arm 18 about an axis running perpendicularly with respect to the carrier 17, namely from the middle position 13 into the fully retracted position 14. When the chassis leg 11 is fully retracted into the position 14, it is also the actuator 21 is fully retracted and locked into the main body of the retraction cylinder 20, so that the chassis leg 11 is also held in the fully retracted position 14. By the control device the supply of pressure medium to the annular cylinder space 36 through the inlet 44 is also interrupted, when the rotatable support arm 18 is out of contact with the an |

impact 32 is rotated, the control device e.g. is thereby put into operation that the microswitch located on the stop 32 by detaching the rotatable Support arm 18 of the actuator of the microswitch is triggered. As can be seen, the pin becomes 35 held in abutment against the upper surface of flange 26 by the spring load.

Under normal operating conditions, the chassis leg 11 is thereby brought into its operating position that pressure medium is first fed to the retraction cylinder 20, whereby the retraction cylinder 20 is unlocked and the actuating member 21 in the axial direction with respect to the I.

Main body of the retraction cylinder 20 is moved. As a result, the chassis leg 11 and the rotatable support arm move 18 together from the fully retracted position 14 to the intermediate position 13. When the actuator 21 with respect to the main body of the retraction cylinder 20 is fully extended, the chassis leg 11 has assumed the intermediate position 13 and the rotatable support arm 18 is against the stop 32. This stop 32 prevents

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a further counterclockwise rotation of the rotatable support arm 18 (see FIG. 4). You can see that the * 'Either 40 engages the pin 35 at the moment brings the opening 27, in which the rotatable support arm 18 rests against the stop 32. In this way the rotatable Body 18 locked against further rotational movement with respect to carrier 17.

The actuator located on the stop 32 Microswitch is operated by the system on the rotatable support arm, so that the central cylinder space between the piston 33 and 39 is supplied through the inlet 45 pressure medium. This causes the piston 33 to move downwards and pressed away from the spring carrier 41, so that the pin 35 also moves in this direction and the lever 28 pivoted against the force of the spring 30. This pivoting of the lever 28 causes the rod 25 to disengage solved with the upwardly open recess 31. The feed of pressure medium to the retraction cylinder 20 causes the actuator 21 to return to the fully retracted Position with respect to the main body of the retraction cylinder 20 is brought. This movement of the actuator 21 gives the chassis leg 11 a related on the rotatable body 18 downward pivoting movement about the horizontally extending axis 19. On this Way, the chassis leg 11 is brought from the intermediate position 13 into the fully extended operating position, the is shown in Figures 2, 3 and 4 with solid lines. The actuator 21 is when it is related has reached the fully retracted position on the main body of the retraction cylinder 20, in that position

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locked so that the chassis leg 11 in his Division of operations is held firmly. The supply of pressure medium to the central cylinder space between the two pistons 33 and 39 is interrupted so that the lever 28 is returned to its position determined by the spring load.

To get out of dissolving in an emergency, the rod 25 upwardly open recess 31 of the lever 28 and to bring the chassis leg 11 from its intermediate position 13, for example, at a failure of the pressure medium supply after working t

actuation of the microswitch located on the stop 32 or in the event of a failure of this microswitch or the associated circuits, the cylinder space can 38 pressure medium can be supplied through the inlet 46 by means of a control device operated in an emergency, so that the upper piston 39 is moved within the cylinder 34 downwards. This movement of the upper piston 39 is transmitted to the lower piston 33 by means of the spring 40, so that the pin 35 also follows can move down and the lever 28 moves against the force of the spring 30, whereby the rod 25 out of engagement with the upwardly open recess 31 of the lever 28 is resolved. One recognizes that the connection of the one I

Fahrzylinders 20 with the Plugzeugzelle 16 at one end and with the chassis leg 11 at the other end with the interposition of universal joints that only one retraction cylinder 20 is sufficient to give the chassis leg 11 a pivoting movement by a horizontal, as well as to give a vertical axis as desired.

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The device according to the invention, which is described above in As has been described in detail, a number of modifications and improvements are susceptible of the invention still includes. For example, the rotatable support arm 18 can be arranged so that it is directly on a suitable part of the plug stuff cell is rotatably arranged and not - as described - on a carrier 17, which is firmly connected to the plug stuff cell 16. The plague control device, which is arranged to be in Cooperation with the correspondingly designed, rotatable support arm 18, a rotation of this rotatable support arm with respect to the plug stuff cell 16 can also be mounted inside the plug stuff cell 16 and does not have to be a part of the fastening device of the undercarriage, e.g. the support 17 in the exemplary embodiment, represent. Furthermore, a coupling can be provided for the undercarriage unit 12, which is that of the undercarriage leg 11 distal end of the retraction cylinder 20 by means of a universal joint with the plug-in tool cell 16, with this coupling device again formed as part of the plug stuff cell 16 and arranged in such a way that it can be in any desired Way nsit one end of the main body of the retraction cylinder 20 is firmly connected.

In the embodiment described with reference to the figures, the chassis leg 11 is completely retracted position 14 or held in the operating position by locking the retraction cylinder 20; however, this can also be done by separate locking devices, one of which is the chassis leg 11 holds in the fully retracted position 14 and the other in the operating position.

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Claims (1)

Claims 1. Device for extending and retracting the landing gear of a ^ —- ^ aircraft, "consisting of a bracket with a rotatable part, which is firmly connected to an airframe, consisting of a retractable chassis leg, that on the rotatable part about an axis that is perpendicular to or parallel to the axis of rotation of the rotatable part runs along such an axis, is pivotably articulated, and from a retraction cylinder of two along an axis mutually movable parts, characterized in that a first part of the Sinfahrzylinders (20) is designed for connection to the airframe (16) via a universal joint that a second part (21) of the retraction cylinder by means of a universal joint (22) with the chassis leg (11) connected and movable together with the chassis leg when the two parts mentioned move against one another is that the chassis leg can be locked against a pivoting movement relative to the rotatable part (18) is, and that the rotatable part. to interact with a locking device (32) (Figure 5) einich tet, wherein a rotary movement of the rotatable part against the airframe is normally not possible is and only when locking the chassis leg against a pivoting movement relative to the rotatable Part is released. -18- 109836/0162 2. Apparatus according to claim 1, characterized in that the rotatable part (18) on one with the airframe (16) fixedly connected carrier (17) is rotatably mounted. 3. Apparatus according to claim 2, characterized in that the carrier (17) has one for cooperation with the rotatable part (18) equipped Peststelleinrichtung (32) (Figure 5). 4. Apparatus according to claim 3> characterized in that that the locking device (32) (Figure 5) consists of a pin (35), and that the pin for cooperation is arranged with a hole (27) in the rotatable part (18). 5. Apparatus according to claim 4, characterized in that the pin (35) under the action of spring pressure engages with the hole (27). 6. Apparatus according to claim 4 or 5, characterized in that the pin (35) with one in a cylinder (34) movable piston (33) is connected, and that the pin out of engagement with the hole (27) can be released by means of a pressure medium pressure exerted on the piston in the cylinder. -19- 109836/0162 Device according to the preceding claims, characterized in that one of a lever (28) and a rod (25) existing locking device is provided that the rod for fitting into a Recess (31) of the lever is formed, and that when engaging the rod in the recess, the chassis leg (11) against movement relative to the rotatable part (18) is locked. 8. Apparatus according to claim 7, characterized in that λ that the lever (28) is attached to the rotatable part (18) and the rod (25) is attached to the chassis leg (11) connected is. 9. Apparatus according to claim 8, characterized in that that the lever (28) under spring load with the recess (31) open at the top on the one with the airframe (16) permanently connected fastening device (17) (18) is arranged. 10. The device according to claim 9 * characterized in, | that the lever (28) at the end part remote from the spring (30) has a convex, of the upwardly open recess (31) has downward curvature and that the lever at a pivoting movement of the chassis leg (11) against the rotatable part (18) by means of the rod (25) the spring pressure for engaging the rod (25) in the recess (31) is movable. 109836/0162 _ ₂₀ _ 11. Device according to claims 4, 9 »10, characterized in that that the hole (27) of the Peststelleinrichtung in a radial flange (26) of the rotatable part (18) and after connecting the fastening device (17, 18) to the airframe (16) directly above the Lever (28) is arranged so that the pin (35) can be pressed through the hole against the upper surface of the lever is, and that the lever by pressing the pin against the spring load releasing the is movable in the upwardly open recess (31) held rod (25). 12. Device according to the preceding claims, characterized in that said first part of the retraction cylinder is designed to be connected to the airframe (16) via a coupling device. 13. Device according to one of claims 1 to 12, consisting of a fastening device on the airframe with a rotatable part for rotation about an axis perpendicular to the airframe, a chassis leg hinged to the rotatable part and pivotable about a horizontal axis, and a retractable cylinder with two parts movable relative to one another along an axis, characterized in that a first part of the retraction cylinder (20) is connected to the airframe (16) via a universal joint and a second part (21) of the retraction cylinder is connected to the chassis leg (11) via a universal joint (22) ) connected is, 109836/0162 -21- that the chassis leg can be locked against a pivoting movement relative to the rotatable part (18) and that the rotatable part for cooperation with a locking device (32) (Figure 5) on the Airframe is formed, with a rotational movement of the rotatable part against the airframe normally not possible and only when the chassis leg is locked against pivoting movement is released relative to the rotatable part. 109836/0162