GB2072255A

GB2072255A - Door operating mechanisms

Info

Publication number: GB2072255A
Application number: GB8009204A
Authority: GB
Original assignee: Rolls Royce PLC
Current assignee: Rolls Royce PLC
Priority date: 1980-03-19
Filing date: 1980-03-19
Publication date: 1981-09-30

Abstract

A door opening mechanism, suitable for a cargo hold of an aircraft or missile in which an ejectable payload is carried, comprises an elongate arcuate door 12 having one or more flexible cables 16 extending from a point of attachment adjacent one edge 13 of the door 12 and extending across the concave side of the door around the other edge and back across the convex surface. A winch 19 operates the cables 16 and the door 12 is rotated such that the open position the cable is tensioned chordwise across the concave side to eject the payload. <IMAGE>

Description

SPECIFICATION Door opening mechanisms This invention relates to door opening mechanisms for a cargo hold, or similar hold, and is particularly concerned with such mechanisms that can be used to assist the ejection from the hold of an ejectable payload.

The invention may be useful for aircraft cargo holds, bomb bays or for missiles having ejectable payloads such as torpedoes or surveillance devices.

With missiles capable of carrying an ejectable payload, such as a torpedo or surveillance equipment, there is a need to be able to eject the payload during flight without disturbing its flight path to an unacceptable degree. If the payload is stowed in a bay within the profile of the missile and ejected through opened doors, it is necessary not to increase the drag by opening the doors into the air stream, and it is also necessary to close the doors to reduce the drag.

An object of the present invention is to provide a door opening mechanism for a cargo hold wherein the mechanism is stowed within the profile of the vehicle, or other structure and which is operable to move the door from a closed position to an open position and back to the closed position in a continuous action.

According to the present invention there is provided a door opening mechanism for a cargo hold comprising an arcuate door which, in a first position, closes off an aperture in a wall of the hold, the door being rotatable from the first position where its concave face points radially inwards into the hold, through a second position where the door lies behind a space in the hold allocated for receiving an ejectable cargo, and the concave face of the door faces outwards from the hold, to a third position where the door closes the aperture, a flexible cable attached to the door adjacent a first longitudinal edge of the door, the cable, when the door is in the first position, passing from its point of attachment to the door, over the concave face of the door, around a second longitudinal edge of the door, and back across the convex surface of the door to a pulling means, the pulling means being operable to pull the cable and thereby rotate the door from the first position through the second position, whereat the cable is pulled taught chordwise across the concave surface of the door, to the third position.

Preferably the door rotates about an axis corresponding to the axis of curvature of the door.

The pulling means may comprise a winch device.

A rewinding mechanism may be provided for rotating the door from the third position through the second position back to the first position. The rewinding mechanism may be a tension spring operable on the door to rotate the door when the pull on the cable is relaxed.

An embodiment of the invention will now be described, by way of an example with reference to the accompanying drawings in which: Figure 1 is a pictorial representation of a missile embodying the mechanism of the present invention.

Figure 2 is a pictorial representation of the missile of Figure 1 with its payload partiy ejected from its cargo hold.

Figures 3 to 6 show a cross sectional view through the mechanism of Figures 1 and 2 showing various stages in the operation of the mechanism.

Referring to Figure 1 there is shown part of a missile 10 having a cargo hold 11 defined by a concave recess facing outwards from the missile.

The cargo hold 11 is provided with an elongate arcuate door 12 which has two longitudinal edges 13, 14 lying parallel to the axis of curvature of the arcuate door 12. The door 12 is mounted in the missile on trunnions 1 5 so as to be rotatable about a longitudinal axis corresponding to the axis of curvature of the door 12. The door 12 is rotatable through one complete revolution.

A number of flexible cables 1 6 are provided for pulling the door to open and close it in the manner described below. Each cable 16 is fixed to the door 12 adjacent to a first of the longitudinal edges 13 and, when the door is in the closed position as shown in Figures 1 and 3 each cable passes from its point of attachment to the door across the concave face, around the second longitudinal edge 14 and back across the convex surface of the door. Each cable passes over a pulley 17 located adjacent that edge of the aperture nearest the first edge 13 of the door 12 when it is in its closed position shown in Figures 1 and 3.Each cable 1 6 is guided by pulleys 18 to a pulling means in the form of a winch 1 9 which is driven either by an electric hydraulic, or pneumatic motor, or by means of an accessory drive shaft driven by a turbine of the missiles propulsion motor.

When pulled, each cable 1 6 is tensioned so that an intermediate portion of cable 1 6 cut on the second edge 14 of the door 12 and advances it in the direction of pull, thereby to rotate the door 1 2.

Rotation of the door continues about it trunnions 1 5 until the door lies behind the space in the hold allocated to receive the ejectable cargo 20, as shown in Figure 4. In this second position the cargo 20 nestles in the concave surface of the door 12 which points outwards from the hold 11 and traps the cables 1 6 between the door 12 and the cargo 20. Further pulling of the cables 16 pulls them taught chordinise across the concave side of the door 12 and ejects the cargo 20 as shown in Figure 5.

Further pulling of the cables 1 6 exerts a pull on the edge 13 of the door and causes the door to continue its rotation until the first edge 13 is located adjacent the pulleys 1 7 and the door closes off the cargo hold 11.

If desired, a rewinding mechanism such as a tension spring may be provided on the trunnions to urge the door to return from the third position, through the second position back to the third position. A door provided with a rewinding mechanism may find application in a system employing magazine loading of ejectable cargoes so that each time the door is returned to its first position, a cargo is loaded into the space allocated for the cargo so that when the door is moved to the second position the cables eject the cargo from the hold.

Claims

1. A door opening mechanism for a cargo hold comprising an arcuate door which, in a first position, closes off an aperture in a wall of the hold, the door being rotatable from the first position where its concave face points radially inwards into the hold, through a second position where the door lies behind a space in the hold allocated for receiving an ejectable cargo, and the concave face of the door faces outwards from the hold, to a third position where the door closes the aperture, a flexible cable attached to the door adjacent a first longitudinal edge of the door, the cable, when the door is in the first position, passing from its point of attachment to the door, over the concave face of the door, around a second longitudinal edge of the door, and back across the convex surface of the door to a pulling means, the pulling means being operable to pull the cable and thereby rotate the door from the first position through the second position, whereat the cable is pulled taut chordwise across the concave surface of the door, to the third position.

2. A door opening mechanism according to claim 1 wherein the door rotates about an axis corresponding to the axis of curvature of the door.

3. A door opening mechanism according to claim 1 or claim 2 wherein the pulling means comprises a winch device.

4. A door opening mechanism according to claim 1 or claim 2 wherein a rewinding mechanism is provided for rotating the door from the third position through the second position back to the first position.

5. A door opening mechanism according to claim 4 wherein the rewinding mechanism is a tension spring operable on the door to rotate the door when the pull on the cable is relaxed.

6. A door opening mechanism substantially as herein-described with reference to the accompanying drawings.