GB2198182A - Plug door: guiding - Google Patents

Abstract

A plug door arrangement comprises a door 1 mounted in a framework for swinging movement between open and closed positions, and an arm 3 that guides one of the vertical edges of the door 1 during such movement. The arm 3 is pivoted at 5 to the door and at 20 and 22 to the framework. During the major part of closing the arm 3 the arm 3 is guided by a cam so that pivot 5 is constrained to pivot about pivot 20. During a final phase of closing the arm is not cammed and link 21 pivots at 22 to extend the arm. This permits the vertical edge of the door 1 to be guided to move in a direction substantially along the plane of the opening for the door to facilitate sealing by seals 56/68. Alternatively (Fig. 3c), release from the cam allows the arm to extend axially against spring bias, or (Fig. 6b) the pivoted arm 3 knocks a toggle linkage over-centre to allow a further link to pivot to extend the arm. <IMAGE>

Description

PLUG DOOR ARRANGEMENTS The invention relates to plug door arrangements.

Hereinafter there will be described in particular plug door arrangements fitted to passenger carrying railway vehicles.

In a plug door arrangement the door plugs into the door frame structure for closure and is swung away from the doorway to a fully open position in which it lies alongside the flank of the vehicle. Mounting and drive actuator arrangements are concealed below the, vehicle floor level or in the vehicle ceiling. In its movement the door should not encroach too greatly over the platform, and in the fully open position should not offer a dangerous obstruction to passengers approaching the doorway along the platform.

According to the present invention there is provided a plug door arrangement comprising a door mounted in a framework for swinging movement relative to the framework between open and closed positions, and an arm that guides one of the vertical edges of the door during such movement, this arm having one end attached via a first pivot to the door and its other end attached via a second pivot to the framework such that during the major part of its movement during door opening and closing the first pivot is constrained to pivot about the second pivot, the connection between the arm and the framework being such that during a final phase of a closing movement of the door the first pivot is freed from such constraint to permit said one vertical edge of the door to be guided by guide means to move in a direction substantially along the plane of the opening for the door in the framework as the edge moves into co-operation with the opposing edge of the framework. In this door arrangement, as the movement of the door is modified from a true arcuate motion towards the end of its closing movement such that one edge of the door moves substantially in the direction along the plane of the door opening, sealing of this edge of the door to the door frame is facilitated.A normal swing door arrangement imparts to the door a fully arcuate movement over the whole of the door trajectory and this excludes the use of a fully interlocking seal because of the substantially transverse component of movement. Generally a "rubbing" seal is used and this is not entirely satisfactory. Final movement of the edge of the door into a closed position in a direction that is substantially along the plane of the doorway permits a fully interlocking seal arrangement to be utilized.

In addition, in the embodiments described hereinafter, the mounting of the door is such that the final movement of the other vertical edge of the door as the door closes is substantially at right angles to the plane of the door opening and this motion, accompanied by final movement of the edge first discussed in a direction substantially along the plane of the door opening, permits the use of locking mechanism that engages the door itself. In plug door arrangements it has been the practice to lock the actuator mechanism, rather than the door directly.

For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure la is a perspective view of a door drive mechanism, Figure 1b s a plan view of a mounting mechanism of a swinging door carried on two pivoted arms, Figures 2a and 2b show in plan and perspective view respectively details of a pivotal mounting for an extensible swinging arm, Figures 3a and 3b are plan and side views of an alternative pivot mounting for the extensible arm, Figure 4 is a detailed plan view of a guide mechanism for the nose edge of the door, Figures 5a, 5b and Sc are plan views showing the construction and illustrating the operation of a door latch release mechanism, Figure 6a is a plan view of another form of mounting mechanism illustrating movement from a door fully opened position to a door nearly closed position, Figure 6b is a detailed plan view of part of the mechanism of Figure 6a, shown in the door fully open position, Figures 7a and 7b and Figures 8a and 8b are views respectively corresponding to Figures 6a and 6b showing different positions of the door, Figure 9 is a perspective view of the nose edge foot of the door, Figure 10 is a perspective view of the parts of the door frame with which the door foot shown in Figure 9 co-operates, Figures 11 and 12 are views corresponding to Figures 9 and 10 but of the top of the door and of the door frame respectively, and Figures 13 and 14 are plan views showing how the parts shown in Figures 11 and 12 co-operate with each other.

Figures 1a, ib, ic through to Figures 5a, 5b and Sc illustrate plug door arrangements suitable for use in a variety of vehicles but, in particular, for use in a passenger carrying railway vehicle. There is a single door and the drive and mounting mechanisms are appropriately handed. It will be appreciated that the door could be opened in the opposite direction by drive and mounting mechanisms of the opposite hand.

Alternatively, double or bi-parting doors could be provided.

Referring to Figures la and ib the door 1 is carried at ends remote from pivot axes of two swinging arms 2 and 3 to which the door is pivotally attached at pivots 4 and 5 respectively. The swinging arms 2 and 3 are mounted below a threshold, i.e. the floor of a railway vehicle. The swinging arm 2 is rigidly attached to a rotatable pole 6 which extends vertically to one side of the doorway.

The rotatable pole 6 is journalled towards its top and bottom ends in the vehicle structure and to one side of the doorway. A second swinging arm 7, essentially identical with the swinging arm 2, is rigidly attached to the pole 6 towards its upper end.

A door actuator piston and cylinder arrangement 8 is mounted above the headframe of the doorway, i.e.

above ceiling level, and is coupled with the rotatable pole 6 by means of mechanism illustrated in Figure la.

One end of the cylinder of the arrangement 8 is mounted on the door frame structure at a pivotal mounting 9 which permits a degree of pivotal movement in a horizontal plane. The piston rod 10 of this arrangement is attached to a cam plate 11 which is also pivoted to the door frame structure at a pivot 12 for pivotal movement in a horizontal plane.

The cam plate 11 has a cam slot 13. Engaged with the slot 13 is a cam follower 14 which is carried towards one end of a cam follower support arm 15 which is rigidly attached to the door operating pole 6.

In operation the door 1 is opened by anti-clockwise rotation (as viewed in Figures la and 1b) of the pole 6, swinging the arms 2 and 7 to move the door 1 towards the right. This is achieved by applying pneumatic pressure to the cylinder of the piston and cylinder arrangement 8 in a sense to extend the piston rod 10.

To close the door pneumatic pressure is applied to the cylinder in a sense to retract the piston rod 10 so that the pole 6 and arms 2 and 7 are rotated in a clockwise direction.

The swinging arm 3 shown in Figure 1b is pivotally mounted on the vehicle structure by an arrangement which permits elongation of the effective length of the arm during part of its movement. Two arrangements will be described for achieving this, the first is illustrated in Figures 2a and 2b and the second is shown in Figures 3a and 3b.

In the arrangement of Figures 2a and 2b the swinging arm 3 is pivotally mounted at a pivot 20 to a link 21 which is pivotally mounted in the fixed structure of the vehicle at a pivot 22. A spring diagrammatically indicated at 23 exerts a bias force on the link 21 about the axis of the pivot 22 to urge the link 21 into abutment with a fixed stop 24 fast with the fixed structure of the vehicle.

A restraining pin 25 is fixed to the arm 3 at a distance from the axis of the pivot 20. Therefore, in swinging motion of the arm 3 about the pivot 20, the retaining pin 25 describes a circular arc having the axis of the pivot 20 at its centre. A plate 26 fixed to the vehicle structure carries a raised and curved abutment 27 the inner face of which follows the arc described by the restraining pin 25. The arc subtended by the curved abutment 27 is smaller, by a few degrees, than the arc subtended by the restraining pin 25 over the full movement of the swinging arm 3. Thus the restraining pin 25 is prevented from deviating from its described arc of movement by the inner face of the curved abutment 27 over virtually the whole of the movement of the door 1 between its fully open and almost closed positions, but clears the abutment as the arm 3 reaches each end of its movement.In particular, as the nose edge of the door 1 moves towards the closed position and the arm 3 nears the end of its movement in this direction, the restraining pin 25 clears the end of the curved abutment 27. Until this occurs the contact between the restraining pin 25 and the curved abutment 27 ensures that the link 21 cannot leave the stop 24 and is thereby prevented from rotating. The only movement of arm 3 permitted is rotation about the axis of the pivot 20. However, when the restraining pin 25 lears the end of the abutment 27 the constraint is removed and the link 21 is freed for rotation about its pivot 22. The effect of this is that the pivot 20 carrying one end of the arm 3 rotates under the influence of a continuing force exerted by the door actuator piston and cylinder arrangement 8.

The effective length of the swinging arm 3 is elongated as the link 21 turns and swings, the link 21 carrying the pivot 20 about the pivot 22 in the closing direction of the door 1, and the pivot 5 by which the arm 3 is connected to the door 1 moves other than by pivoting about the pivot 20.

In the alternative arrangement illustrated in Figures 3a and 3b the swinging guide arm 3 is mounted for horizontal pivotal movement about a vertical pivot 30 by mechanism including a lost motion arrangement controlled by a curved plate 32 which carries an abutment 34. One end of the arm 3 is attached to a yoke 36 by a pivot pin 40, the door having some freedom for movement in a vertical plane for door alignment.

To provide for extension of the arm 3, the yoke 36 is slidably mounted in a block 38 that is pivotally mounted at the pivot 30 and which forms part of a lost motion mounting permitting the arm 3 and pivot pin 40 to move in a direction transversely of the axes of the pivot pin 40. Two studs 42a, 42b project rearwardly from the yoke 36 and pass through closely fitting holes in the block 38, one on either side of the pivot 30.

Screw-threaded ends of the studs receive lock nuts 44a, 44b which retain on the ends of the studs a restraining member 44. The length of the studs 42a, 42b is such that there is a free space between the restraining member 44 and the block 38. Bias springs 48a, 48b one on each of the studs 42a, 42b are trapped behind the restraining member 44 and urge the member 44 and block 38 apart. A depending portion 45 on the restraining member 44 lies outside the curved abutment 34.

Engagement of the portion 45 with the abutment 34 prevents the free length of the studs 42a, 42b being taken up by axial movement of the arm 3 with the restraining member 44 moving along the studs, until the portion 45 has swung clear of the end of the abutment 34.

Again, as with the arrangement of Figures 2a and 2b, the arc subtended by the curved abutment 34 is almost equal to the length of arc described by the restraining member 44 over the full range of pivotal movement of the arm 33. However, as before, as the arm 3 swings the door towards the closed position, but is still a few degrees short of its terminal position, the restraining member 44 is swung beyond the end of the curved abutment 34. As constraint is removed, the lost movement can be taken up effectively to elongate the arm 3 by the length of the free space between the block 40 and the restraining member 44, and thus the pivot 5 by which the arm 3 is connected to the door 1 moves other than by pivoting about the pivot pin 40.

In the arrangements of Figures 2a, 2b, and 3a, 3b the plates 26 and 32 are provided with elongate fixing holes 50 which permit a degree of rotary alignment of the plates, about the swing axis of the arm 3, for adjustment of the point at which the abutment plates release for movement either the link 21 or the block 38.

Figure 4 shows a view of the nose edge of the door at the point towards the closed position of the door 1 at which extension of the effective length of the arm 3 occurs. It also illlfstrates a preferred guide arrangement for the nose edge of the door 1. The doorway frame or vehicle structure is indicated at 52, and the outer vehicle skin is indicated at 54. In the doorway itself the frame 52 is stepped inwards to form a recess which receives the nose edge of the door so that the outer skin of the door 1 lies flush with the outer vehicle skin 54 when the door is closed. The vertical nose edge of the door 1 carries a full length moulding 56 which constitutes the door mounted part of a fully interlocking door seal.The opposite part 58 of the engaging seal is secured to the vertical shut face 60 in the doorway recess and completely engages the moulding 50 when the door is fully closed. On the inner face of the door at its nose edge, at the top or bottom or at both, there is attached a bracket 62 which projects forward and carries at its end a jockey wheel 64. At the position shown in Figure 4 this wheel 64 contacts the face 66 of a guide on the door frame.

This arrests the arcuate or lateral motion of the nose edge of the door and continued force exerted by the actuator produces a reaction which brings about the extension of the guide arm 3. The nose edge of the door now changes direction and with a linear forward motion moves in a longitudinal direction, i.e.

longitudinal relative to the vehicle substantially along the plane of the opening for the door. Meanwhile the tail edge of the door has an essentially transverse movement, that is substantially at right angles to the plane of the opening, akin to the motion of a slam door, and this enables slam type locks or latches to be fitted at this edge.

At the position shown in Figure 4 the door 1 has reached the position when the restraining pin 25 or restraining member 44 has cleared the end of the curved plate and the arm 3 may be extended. Also at this same point the actuator piston and cylinder arrangement has not yet reached the end of its closing stroke, i.e. the piston rod 10 (see Figure 1a) is not yet fully extended. In its final phase of movement the actuator piston and cylinder arrangement exerts a force which causes the axial extension of the arm 3. At the same time as the nose edge of the door 1, as shown in Figure 4, moves the remaining short distance to the fully closed position in a substantially linear direction, the (or each) guide wheel 64 enters a linear guide channel 65 which prevents the nose edge of the door moving laterally. Thus, when locks on the tail edge of the door are engaged and if there are guide wheels 64 at the top and bottom corners of the nose edge that are engaged in their guide channels, these wheels effectively act as further locks or latches and the door is locked or latched at all four corners.

If one or both of the guide wheels 64 fails to move fully into its guide channel because, for example, the door is obstructed, then the door will fail to close. The guide wheel, if prevented from entering the guide channel, will abut the end face in front of the channel entrance and a sustained force from the actuator piston and cylinder arrangement will cause the door to jam in this position. The door will not fully close, but also the metal edges at the nose and tail edges of the door will not be forced into close proximity or contact thus reducing or obviating injury to an obstructing passenger.

As a result of the mechanical arrangement adopted to convert the actuator piston and cylinder arrangement output stroke into door movement, a relatively low force only is exerted on the door while it is in motion. Thus, it does not require great effort to prevent the door closing so that the risk of injury to a passenger is correspondingly reduced Higher forces are applied to the door, however, at the very end of the closing movement in order positively to shut the door and operate slam type locks or latches, and also to overcome the spring bias force to permit guide arm extension thus about bringing the linear motion phase of the door.

Figure 1a shows the door actuator piston and cylinder arrangement with its piston rod fully extended and the cam driving arrangement 11/13/14 in position when the door 1 is fully open. As the piston rod 10 is retracted the cam plate 11 rotates about the pivot at 12 and the hidden face of the cam slot 13 bears against the cam follower 14 and rotates its support arm 15.

The pole 6 is similarly rotated and swings the arms 2 and 7 to close the door During this period of rotation the cam follower 14 runs along the cam slot 13 towards the inner edge of the slot The greater part of the slot 13 is formed in substantially radial alignment with the axis of the pivot 12 of the plate 11. As the door reaches the almost closed position the cam follower 14 reaches a point 13a at which the cam slot 13 curves away from radial alignment.

The piston rod 10 is pivotally attached to the cam plate 11 at a point towards the outer end of the plate 11. Thus, as the piston rod 10 is retracted and the cam follower 14 tracks along the slot 13 in a radially inward direction, the mechanical advantage of the coupling between the rod 10 and the pole 6 gradually decreases. Just past the point 13a in the cam slot this mechanical advantage moves into a very high moment phase and a significantly higher force is exerted to overcome the bias force of spring 23 or springs 42a, 42b, of the two lost motion arrangements and bring about the extension of the swinging arm 3.

The hockey stick shaped cam profile shown in the drawings is only one example of possible cam profiles which may be designed to provide, within a wide range, any desired variation of mechanical advantage possessed of the actuator door-drive mechanism.

The overall trajectory of the door 1 is governed by several variable factors in the arrangement. The door mounting arrangement has four pivotal axes identified as A,B,C,D in Figure 1b. The arms 2 (and 7) have axes A and B while the axes C and D are at opposite ends of the normal length of the arm 3. In the fully closed position a line through axes A and C is parallel to a line through axes B and D, so that the four axes are at the corners of a parallelogram. It is preferred if the distance between the axes D and B (i.e. those carried on the door) is greater than the distance between the axes A and C (i.e. those in the vehicle structure). It is found that with these spacings the angular attitude of the door with respect to the vehicle is most favourable.

If the axes A and C are coincident then the door 1 will swing through a circular arc. As the axes A and C move apart the arcuate trajectory of the door is increasingly flattened. With the inter-axes spacings selected in the described embodiment as the door reaches the position shown in Figure 4 the nose edge of the door is angled inwards towards the side of the vehicle, i.e. the axis D is closer to the vehicle than the axis B. As mentioned above this position is reached when the actuator piston rod 10 is almost fully retracted and the cam follower 14 has reached the point 13a in the cam slot. The final phase of retraction of the rod 10 continues to rotate the pole 6 with increased mechanical advantage.As well as causing the effective elongation of the arm 3 the continued slight rotation of the arms 2 and 7 produces a final "plugging" motion at the tail edge of the door, that is the tail edge moves substantially at right angles to the plane of the door opening into its door fully closed position.

In the fully open position the axis D carried by the door is spaced further apart from the side of the vehicle than is the axis B. The tail edge of the door therefore lies closer to the vehicle side and this is considered preferable so that passengers making their way along the platform towards the door do not encounter either an edge of the door, against which they may be injured, or a space in which luggage and limbs may be trapped. Also, the risk of wind gusts generating sufficient force on the door to move it in the closing direction is reduced.

The arrangement also permits a preferred latching arrangement for locking the door to be adopted. In the final phase of a closing movement the nose edge of the door moves in the direction along the plane of the door opening whilst the tail edge of the door moves at right angles to this plane. Thus, it is possible to employ latches the parts of which are mounted directly on the door and the vehicle frame, which engage in the closed position, rather than employing the normal arrangement of a swinging door in which the actuator drive mechanism has to be locked. As a result of this the drive mechanism may be of a lighter construction since it does not have to withstand the forces transmitted through a lock mechanism. Also, the door itself may be latched at all four corners and is thus more securely anchored to the vehicle structure when closed.

Figures 5a, 5b and Sc illustrate the construction and operation of a door latch release mechanism utilising an initial movement of the cam plate 11.

With reference to these illustrations and Figure la, like parts have like references.

The door latch or lock mechanisms, which are of well known type but not shown in the drawings, are released by a Bowden cable arrangement generally indicated at 70 in Figure Sa. An outer sheath 71 of the cable is anchored to an earth point on the vehicle structure or on the door frame at 72, and the inner relatively movable release cable 73 is connected to a lever 74 pivotally mounted on the door frame or fixed structure at a pivot 75. The lever 74 consists basically of an L-shaped member pivoted about an axis passing perpendicularly through the common region connecting the two arms 74a and 74b of the lever 74.

The cable 73 is attached to one end of the longer arm 74a of the two arms. The shorter arm 74b carries a foot 77 pivoted for rotary movement about a pivot 78 in the plane of the L-shaped lever 74. The heel of the foot 77 has a raised portion 79 which abuts the end face of the arm 74b restraining the foot 77 from clockwise rotation. A rotary bias spring 80 mounted concentrically on the pivot 78 engages the foot 77 and the arm 74b to urge the foot 77 in a clockwise direction. Thus, the foot 77 is capable of partial rotation against the bias of a spring 80.

The lever 74 is pivotally mounted immediately above and close to the plane of movement of the cam plate 11. A striker pin or roller 81 is carried by the cam plate 11 in a position which brings it into contact with the curved end surface 82 of the foot 77 during an initial ten degrees or so of rotation of the cam plate 11 during door opening. Over that ten degrees of contact the roller 81 bears against the curved end face 82 of the foot 77. The curve of the surface 82 governs the point of contact between the roller 82 and the foot 77 and is designed to produce a force in the member in a direction which is substantially tangential to a radius about the pivot 75.

By the time the cam plate 11 has rotated through the ten degrees mentioned above, see Figure 5b, the lever 74 has been turned sufficiently to exert enough pull on the cable 73 to operate the door locks to their release position to permit the door to open. At this point the roller 81 has also reached the toe of the foot 77. As the end face 82 curves around the toe over the next few degrees the direction of the force exerted by the roller on the foot backs in a clockwise direction and pushes the foot 77 aside, see Figure Sc.

This action restores the lever 74 to its initial position, releasing the tension in cable 73 and setting the door locks for subsequent locking when the door is next closed. The cam plate 11 continues rotating unimpeded.

The short hooked end of the cam slot 13, beyond the point 13a in Figure la, is broadened slightly to permit an initial ten degrees of lost motion between the cam plate 11 and the cam follower 14 carried by the arm 15. The cam slot profile in the region indicated by arrow 84 is broadened on a radius centred on the axis of the pivot 12 to provide the lost movement.

Thus the cam plate 11 is rotated through the initial ten degrees by energisation of the actuator piston and cylinder arrangement 8 in order to release the door locks before the actuator moment is exerted on the arm 15, through the cam follower 14, to commence opening the doors.

When the door closes, the cam plate 11 moves in a clockwise direction towards the position shown in Figure 5c at which the roller 81, returning to the start position of Figure 5a, strikes the underside of the foot 77. The foot 77 is permitted a limited rotational movement and is pivoted against the spring 80 as the roller 81 moves past. The lever 74 remains stationary as the door closes and the slam locks on the door engage.

An emergency release may be provided quite simply by connecting the moving part of a further Bowden cable to effect rotation of the lever 74 when an emergency handle (not shown) is pulled. This movement of the lever 74 is transferred to the release cable 73 which allows release of the door locks directly without involving energisation of the actuator. Immediately upon the door locks being released the energy stored in the spring 23 biasing the extendible guide arm acts to eject the door from its closed position. Although this does not open the door very far it is sufficient to make it self-evident to passengers that the door is both unlocked and ready to be fully opened by manual effort.

Referring now to Figures 6a, 6b, 7a, 7b and 8a, 8b, and first to Figure 7a which is comparable with Figure 1b, the door 1 is again carried by the two swing arms 2 and 3. The arm 2 is as the arm 2 already described.

One end of the arm 3 is pivotally connected by a pivot 100 to one end of a radius arm 101 the other end of which is pivotally connected to the vehicle structure at a pivot 102. The pivot 100 also pivotally connects the arms 3 and 101 to a pair of toggles 103.

The toggles 103 are also pivotally connected, at a pivot 104, to one end of a link 105. The other end of the link 105 is pivotally connected to the vehicle structure at a pivot 106. The link 105 co-operates, through a bias spring 107, with a fixed stop 108. The toggles 103 carry a stop 109 for co-operation with the radius arm 101.

As in the embodiments previously described, the nose edge of the door 1 carries a guide roller 64, near its bottom, that enters a guide channel 65 as the door closes (see also Figures 9 and 10). The roller 64 can be resilient.

In the door fully opened position illustrated in full lines in Figure 6a and in Figure 6b the link 101 is held against the toggle stop 109 by the effect of the bias spring 107 acting through the link 105. The link 101 is substantially in line with the arm 3. The pivots 100, 104 and 105 are almost .n line, the pivot 104 being in a slightly over-centre position relative to a line interconnecting the axes of the pivots 100 and 106. The pivots 102 and 106 are at spatially fixed positions. The pivot 100 is at this stage held positionally rigidly fixed by its triangular relationship with the pivots 102 and 106 to achieve an effect similar to that achieved by the co-operation of the restraining pin 25 or the restraining member 44 with the abutment 27 or 34 in the embodiments described above.That is, as the door closes the pivot connection between the arm 3 and the door 1 is constrained to a truly arcuate motion, about the pivot 100, and the door swing locus is positively controlled, moving about fixed centres, until the door reaches the nearly closed position shown in chain lines in Figures 6a and 6b.

As the door nearly closed position is reached a striker 110 carried by the arm 3 comes into contact with the link 105 and shifts the link 105 to move the pivot 104 out of its over-centre locking position to the position illustrated in Figures 7a and 7b. The striker 110 is adjustable so that the extent of its projection from the arm 3 can be set to determine that the over-centre break occurs after the wheel 64 has passed a point at which a catch plate 65A at the channel 65 becomes an effective restraint to forward movement of the door edge, but just before the wheel 64 fully engages in the channel 65. As a result, as the over-centre break occurs, control of the nose edge of the door passes from the arm 3, the pivot 100 now being free, to the wheel 64 engaging in the channel 65.

The wheel 64 runs along a cushioned landing strip 65B, that extends parallel with the vehicle side, into a fully home position in the channel 65, shown in Figure 8a, the nose edge of the door moving in the direction substantially along the plane of the door opening. This is possible because, once the overcentre breaking of the pivot 104 has occurred, and the pivot 100 has been freed, the radius arm 101 pivots about the pivot 102 with the arm 101 moving away from the toggle stop 109 (Figure 7b). The pivot 104 moves towards the pivot 102, this movement being accommodated by the bias spring 107, and the effective length of the arm 3 extends. The pivot connection between the arm 3 and the door 1 moves other than about the pivot 100.

The tail edge of the door moves substantially at right angles to the plane of the door opening as it moves to its fully closed position.

In addition to the co-operation between the wheel 64 and the catch plate 65A and landing strip 65B at the foot of the door, there is co-operation at the top of the door between a locking peg 111 fixed to the upright of the door frame and a peg receptacle 112 carried by the door (Figures 12 to 14). As the door moves into the fully closed position the peg 111 engages in the receptacle 112 as illustrated in Figures 13 and 14 so that the nose edge of the door is secured top and bottom.

In Figures 9 to 12 a door nose edge seal is shown at 113 but seals carried by the door frame are omitted.

Not shown in the drawings is a single lock that secures the tail edge of the door to the door frame.

This lock is disposed mid-way along the tail edge.

Alternatively, there can be two locks on the tail edge, one near the top and one near the bottom. The final closed position is with the door closed and locked, flush with the vehicle side and held securely to the vehicle structure top and bottom.

During door opening the movements described above are reversed. After release of the lock(s) securing the tail edge and as the door commences to move out, the tail edge moves slightly out whilst the wheel 64 disengages from the guide channel 65, and the peg receptacle 112 disengages from the peg 111. The pivot 100 moves as the arm 3 moves with the door and the bias spring 107 asserts itself to move the link 105 and the toggles 103 to over-centre lock position before the wheel 64 clears the catch plate 65A. Thereafter movement of the door is arcuate.

In all the embodiments described as the door moves into its fully closed position the final movement of the nose edge is in a direction substantially along the plane of the doorway whilst the final movement of the tail edge is substantially at right angles to this plane. As a result, a fully interlocking seal arrangement can be utilised at the nose edge, and the door can be locked closed by locking mechanism engaging with the door itself.

Claims (12)

1. A plug door arrangement comprising a door mounted in a framework for swinging movement relative to the framework between open and closed positions, and an arm that guides one of the vertical edges of the door during such movement, this arm having one end attached via a first pivot to the door and its other end attached via a second pivot to the framework such that during the major part of its movement during door opening and closing the first pivot is constrained to pivot about the second pivot, the connection between the arm and the framework being such that during a final phase of a closing movement of the door the first pivot is freed from such constraint to permit said one vertical edge of the door to be guided by guide means to move in a direction substantially along the plane of the opening for the door in the framework as the edge moves into co-operation with the opposing edge of the framework.

2. A plug door arrangement as claimed in Claim 1, wherein said guide means comprises members mounted on said edge of the door and on said opposing edge of the framework for co-operation with one another.

3. A plug door arrangement as claimed in Claim 2, wherein said members are a wheel and a guide channel arrangement into which the wheel enters as the door reaches its closed position.

4. A plug door arrangement as claimed in Claim 3, wherein the guide channel arrangement includes a landing strip for the wheel that serves to guide the wheel into a guide channel proper.

5. A plug door arrangement as claimed in any one of Claims 1 to 4, wherein said second pivot is supported in the framework so as to be movable in the direction transverse of the pivot axis of the second pivot during said final phase of a closing movement of the door.

6. A plug door arrangement as claimed in Claim 5, wherein said second pivot is carried by a link that is attached via a third pivot to the framework and that is resiliently biased into an at-rest position during said major part of the door movement; and wherein the arm carries restraining means that co-operates, during said major part of the door movement, with abutment means fast with the framework thereby to determine that this movement takes place about said second pivot; the extent of the abutment means being such that the restraining means disengages therefrom at the end of said major part of the door movement whereupon the link and the second pivot carried thereby are permitted to move against the resilient bias in turn to permit said edge of the door to be guided to move in said direction substantially along the plane of the door opening.

7. A plug door arrangement as claimed in Claim 5, wherein said second pivot is carried by a support that is movable in the direction transverse of the axis of the second pivot; and wherein the support carries restraining means that co-operates, during said major part of the door movement, with abutment means fast with the framework thereby to prevent transverse movement of said second pivot and determine that the arm movement takes place about said second pivot; the extent of the abutment means being such that the restraining means disengages therefrom at the end of said major part of the door movement whereupon said support is permitted to move in the direction transverse of the pivot axis of said second pivot in turn to permit said edge of the door to be guided to move in said direction substantially along the plane of the door opening.

8. A plug door arrangement as claimed in Claim 5, wherein said second pivot is carried by a radius member that is attached via a third pivot to the framework, and wherein the arm is also attached, via said second pivot, to a toggle arrangement in turn connected via a fourth pivot to a link that is attached via a fifth pivot to the framework; the radius member, the toggle arrangement and the link being resiliently urged into positions such that said second pivot is held at a spacially fixed position relative to said third and fifth pivots during said major part of the door movement whereby it is determined that movement of the arm takes place about said second pivot; the arm carrying striking means that shifts the link at the end of said major part of the door movement to move said fourth pivot relative to said third and fifth pivots thereby to permit said second pivot also to move relative to said third and fifth pivots and thus to permit said edge of the door to be guided to move in said direction substantially along the plane of the door opening.

9. A plug door arrangement as claimed in any one of the preceding Claims, wherein the door is supported by upper and lower swing arms that swing together about a common pivot axis to effect said swinging movement of the door and that move the other vertical edge of the door substantially at right angles to the plane of the opening for the door in the framework as this other edge moves into co-operation with the edge of the framework that opposes it.

10. A plug door arrangement as claimed in Claim 9 and comprising locking mechanism that engages between the door and the framework to lock the door in closed position.

11. A plug door arrangement as claimed in Claim 10, wherein the locking mechanism comprises a lever connected remotely to actuate door locking means, this lever being pivotally mounted on the framework and pivotally supporting a foot that co-operates with actuator mechanism that drives the door to open and close, the foot being resiliently biased to urge the lever to move fast therewith, and the actuator mechanism acting on the foot engaged with the lever, during an initial phase of opening movement of the door, to pivot the lever to release the door locking means and permit the door to open and thereafter to restore the lever to its initial position to set the door locking means for subsequent locking when the door is next closed, the actuator mechanism acting on the foot to pivot the foot against its resilient bias and without pivoting the lever, during door closing, so that the door locking means remains set for locking the door.

12. A plug door arrangement substantially as hereinbefore described with reference to Figure la and either Figures 1b, 2a, 2b and 4, or Figures 3a, 3b and 4, or Figures 6a, 6b, 7a, 7b, 8a, 8b and 9 and 10, all with or without Figures Sa, 5b and Sc and with or without Figures 11 and 12, of the accompanying drawings.