WO2002079018A1

WO2002079018A1 - Bridge

Info

Publication number: WO2002079018A1
Application number: PCT/GB2002/001190
Authority: WO
Inventors: Carl John Woolley
Original assignee: NEVILLE RAIL PROJECTS Ltd
Current assignee: NEVILLE RAIL PROJECTS Ltd
Priority date: 2001-03-28
Filing date: 2002-03-27
Publication date: 2002-10-10
Anticipated expiration: 2003-09-28
Also published as: EP1373046A1; GB0107709D0

Abstract

A bridge for providing access to or from a carriage consists of a cassette housing (34, 58, 76, 110) in which a stage (22, 56, 74, 112) is movable between an extended position in which the stage (22, 56, 74, 112) extends outside of the carriage, and a stowed position in which the stage (22, 56, 74, 112) does not project from the train carriage. The stage (22, 56, 74, 112) is reciprocable between extended positions on either side of the carriage and may be manually deployed or power-operated. The bridge includes upstands (26, 88) to inhibit movement of a wheeled vehicle over a side of the stage (22, 74), the upstands (26, 88) being movable between an operative position in which the upstands (88) projects upwardly from the stage (22, 74), and an inoperative position in which the upstands (88) are substantially parallel with the upper suface of the stage (22, 74). The upstands (88) are suitable for use on any wheelchair access means.

Description

TITLE: Bridge

The present invention relates to abridge, more particularly, but not exclusively, to abridge for providing access to or from a carriage or vehicle.

By the term bridge is intended ameans for access between two spaced apart surfaces, for example between the doorway of a train carriage and a stationplatform. The term bridge is intended to cover any such means of access, whether inclined to or parallel with the two surfaces.

It is a requirement for a train carriage to have access provisions for disabled persons, for example in wheelchairs, hi this respect, most new passenger train carriages are provided with doors which are compatible with wheelchairs. It is known to provide a train carriage with a removable access means, to enable a wheelchair to gain access to the train carriage from a station platform, for example. A known access means consists of a wheel chair compatible ramp which is securable at the base of a carriage doorway, to provide a gangway between the train carriage and a station platform. Another known access means consists of a wheel chair compatible platform, securable onto a carriage doorway, which can be raised or lowered between the level of a train carriage floor and a station platform.

Typically, such aknown removable access means is foldably stored in a storage facility located adjacent to a train carriage doorway. However, storage space on atrain carriage is particularly limited in the area adj acent to a doorway, since safety regulations require a doorway to be provided with additional structural reinforcement to the main structure of the carriage body. Alternatively, such a known access means is stored in a storage facility on a station platform.

In either case, amember of the train company or platform staff is required to put the access means in place, and therefore has to be notified when a passenger requires the use of the access means . When required, the access means has to be removed from storage, secured in place at the doorway, and/or operated, and then removed and returned to storage. This can be a lengthy time process, which can have considerable financial implications for the train company if the train is delayed at a station, p articularly if the delay is passed on to the j ourney of trains further down the line. Delays can be increased, for example, if more than one passenger requires use of the access means, particularly since it is common for only one such access means to be provided on each carriage/platform.

It is an obj ect of the invention to reduce, or substantially obviate, the disadvantages of the lαio wn access means for use on carriages referred to above.

According to a first aspect of the invention, there is provided a bridge for providing access to or from a carriage or vehicle comprising a retractable stage movable, in use, between an extended position in which the stage extends laterally of the carriage or vehicle, and a stowed position in which the stage does not proj ect from the carriage or vehicle, characterised in that the stage is reciprocable between extended positions on either side of the carriage or vehicle.

In apreferred embodiment, the bridge includes a housing in the form of a cassette, within which the stage is reciprocable. The housing may include a plurality of guide members, the stage being movable withm the housing between the guide members, which may extend substantially along the length of the housing.

Conveniently, the guide members consist of upper and lower guide members provided on either side of the housing, between which the stage is slidably supported

The bridge may include means provided adj acent both ends of the housing, for preventing removal of the stage from the housing, Furthermore, means maybe provided at both ends of the housing, for providing a transition between the housing and the upper surface of the stage in the extended position. Themeans forprovidingatransitionbetween the housing and the upper surface ofthe stage preferably consists of a cover plate hingeably connected to the housing, for hingeable movement as the stage is extended or retracted. Preferably, each end ofthe stage includes a spring-loaded pivotably connected end section, for supporting the stage as the stage is extended or retracted.

The stage may include an upstand positioned substantially along the length of each longitudinal edge ofthe stage, for inhibiting movement of a wheeled vehicle, such as a wheelchair, over a longitudinal edge ofthe stage. Conveniently, each pstandismovablebetweenanoperativepositionin which the upstand projects upwardly from the stage, and an inoperative position in which the upstand is substantially parallel with the upper surface ofthe stage.

According to a second aspect ofthe invention, there is provided abridge for providing wheelchair access comprising a stage having at least one upstand to inhibit movement of a wheeled vehicle over a side ofthe stage, characterised in that the or each upstand is movable between an operative position in which the upstand projects upwardly from the stage, and an inoperative position in which the upstand is substantially parallel with the upper surface ofthe stage.

Preferably, the or each upstand is J-shaped having a straight arm portion and a curved endportion, and that the stage includes at least one recess for receiving the curved end portion of the or each upstand.

The or each recess may have an internal profile shaped for operatively receiving the or each upstand, for movably locking the upstand in the extended position. The upper portion ofthe internal profile may include a knuckle formation having an arcuate profile, and an undercut surface which terminates at a rectangular return surface and the lower portion ofthe internal profile may includes a curved transition surface, for operative interaction with the upstand during movement of the upstand between the operative and inoperative positions.

Other preferred features ofthe invention can be found in the dependent claims.

There is also provided a carriage or vehicle whenever provided with abridge according to the first or second aspect ofthe invention. The invention will now be described, byway of example only, with reference to the accompanying drawings, in which:

Figure 1 is a diagrammatic perspective view, partly in section, of a train carriage fitted with a bridge in accordance with the invention;

Figure 2 is a plan view, partly in section of a train carriage fitted with the bridge of Figure 1;

Figure 3 is a diagrammatic view a control arrangement for a preferred power-operated embodiment ofthe invention;

Figures 4A-D show a series of schematic cross sectional views of a preferred embodiment of a bridge in accordance with the invention;

Figure 5 is a diagrammatic perspective view ofthe bridge of Figures 1 and 2, showing the bridge in use in an alternative application;

Figure 6 is a cross sectional view from the side of a modified embodiment of a bridge in accordance with the invention, showing the bridge in a stowed position;

Figure 7 is a cross sectional view ofthe bridge in Figure 6, in a deployed position;

Figure 8 is across sectional view from one end of a bridge in accordance with the invention, showing a preferred upstand;

Figure 9 is an enlarged view of a side panel ofthe stage in Figure 8;

Figure 10 is a cross-sectional plan view of one end of a still further modified embodiment of abridge in accordance with the invention, showing the bridge in a stowed position; Figure 11 shows the bridge in Figure 10 in a fully deployed position to the right as viewed;

Figure 12 shows the bridge in Figures 10 and 11 in a deployed position to the left as viewed; and

Figure 13 shows a detail of a part of the bridge in Figures 10 to 12.

Referring to Figure 1 , a train carriage 10 is illustrated connected to a train carriage 12, only the adjacent end section of each carriage 10, 12 being visible.

With particular reference to carriage 12, the carriage 12 includes apair of doorways 14, 16 in transverse alignment with one another, with respect to the longitudinal axis ofthe carriage 12. The doorways 14, 16 are each ofawidthwhichis compatible for wheelchair access. Thecarriage 12 also includes a floor panel 18.

A bridge in accordance with the invention, generally indicated at 20, is located in the floor panel 18. The bridge 20 consists of a retractable stage 22 which is positioned in general alignment with the doorways 14, 16. The stage 22 includes a spring-loaded ivotably connected end section24, at each end ofthe stage 22 (only one of which is visible) . The purpose of each end section 24 is to support the stage 22 as it is extended or retracted from the carriage. The stage 22 also includes an upstand 26 positioned substantially along the length of each longitudinal edge ofthe stage 22, for inliibiting movement of a wheeled vehicle, such as a wheelchair, over a longitudinal edge ofthe stage 22.

The stage 22 is movable between an extended position in which the stage 22 extends outside of the train carriage 12 (as illustrated in Figure 1), and a stowed position in which the stage 22 is contained within the floorpanel 18 and does not project from the train carriage 12. As indicated by the arrows in Figure 1 , the stage 22 is reciprocable between extended positions on either side ofthe carriage 12. Referring now to Figure 2, the bridge 20 is shown in a fully extended position on the right hand side ofthe carriage 12, as viewed. The dotted outline, designated 28, indicates the fully extended position ofthe bridge 20 on the opposite side ofthe carriage 12. As can be seen, the stage 22 consists of a central leaf 30 having apivotally connected end section 24 provided at each end of the leaf 30. In the fully extended position, one ofthe end sections 24 remains substantially within the floor panel 18, as will be described in more detail with reference to the preferred embodiment below.

The stage 22 can be manually deployed, for example by holding an end ofthe stage 22 and pulling the stage 22 outwardly from the train carriage. Alternatively, the stage 22 can be power operated, for example using any suitable hydraulic, pneumatic or electrical means. When the bridge is power- operated, an associated control circuit and control panel is also be provided. A typical control arrangement is shown in Figure 3. The control panel A including a "deploy' ' control button B and a "retract" control button C will be installed adj acent a carriage doorway at aheight compatible for a wheel chair user, in accordance with the Rail Vehicle Accessibility Regulations 1998. To deploy the stage 22 from the stowed position, the deploy button B is pressed and the stage 22 begins to extend progressively from the train carriage to the fully extendedposition. To retract the stage 22 from an extended position, the retract button C is pressed, to initiate movement ofthe stage 22 back to the stowed position. A trip switch maybe provided to prevent the carriage doors being closed when the stage 22 is in a deployed position. The bridge 20 can also be operated automatically, for example as the carriage doors are opened or closed.

Referring now to Figures 4A to 4D, a preferred embodiment of the bridge 20 is shown schematically in use between a train carriage 12 and a station platform 32. Common reference numerals are used to designate similar components ofthe previous embodiment.

As shown in the above embodiment, the bridge consists of a stage 22 including a central leaf 30 having a spring-loaded pivotally connected end section 24 at each end ofthe leaf 30.

The bridge 20 includes ahousing 34 contained within the floor panel 18 ofthe carriage 12. The housing 34 has ofa plurality of guide members, onlythe upper and lower members 36, 38 being visible. The guide members are vertically and laterally spaced, in alignment with a doorway in the carriage 12, the stage 22 being slidably supported between the guide members. In this respect, the housing 34 forms a "cassette" in which the stage 22 is reciprocable between the guide members. A stop 40 is provided at each end ofthe housing 34, to prevent the stage 22 from being removed from the housing 34, in use. In this embodiment, the stop 40 consists ofa stop formation provided on each end ofthe guide members 36. A flap in the form of cover plate 42 is hingably connected along a top edge of each end ofthe housing 34, the plate 42 being hingably movable as the stage 22 is extended from the carriage 12.

Movement ofthe stage 22 from a stowed position on the carriage 12 to a fully extended position onto the station platform 32 will now be described.

With the carriage 12 stationary at the platform 32, the doors ofthe carriage 12 are opened. In this embodiment, the stage 22 is power operated and, in use, is extended gradually from a stowed position, after a button is depressed on an associated control panel, for example.

The co ver plate 42 is hingably displaced as the stage 22 first protrudes from the housing 34, and provides a smooth transition between the housing 34 and the upper surface ofthe stage 22, e.g. • for smooth passage of wheel chairs thereover.

As shown in Figure 4a, as the end section 24 is extended from the housing 34, the spring-lo aded pivotal connection to the central leaf 30 urges the leading edge end section 24 to fall in contact with the platform 32. The pivotal connection is spring-loaded to act against the cantilever effect ofthe central leaf 30, as it extends progressively from the housing 34. Hence, the end section 24 is designed to provide support for the progressively extending central leaf 30 (as illustrated in Figure 4b).

hi this embodiment, the upstands 26 consist of aplurality of spring-loaded panels which "pop up" progressively as the stage is extended from the housing 34. As the stage 22 is extended further, the central leaf 30 begins to incline to the platform 32 (Figure 4c), as the spring loaded connection ofthe end section is gradually overcome. From this point, the end ofthe stage 22 within the housing 34 (i. e. at the left hand side, as viewed) is biased into contact with the upper guide member 38.

The stage 22 is extended until the pivotal connection at the left hand end ofthe stage 22 comes into contact with the stop 40 (the fully extended position, as illustrated in Figure 4d). In this fully extended position, the spring loaded connection ofthe end section 24 is fully overcome, and the stage 22 provides a planar inclined gangway between the carriage 12 and the platform 32.

After use, the stage 22 is retractable within the housing 34, to return to a stowed position within the carriage 12, for example, by depressing a button on the associated control panel.

Although not illustrated, rollers or wheels maybe fitted to the leading edge ofthe end section 24, to reduce frictional contact between the stage and the platform surface, as the stage is extended/retracted.

Whereas the above embodiment ofthe invention has been described with reference to a spring- loaded, pivotally connected end section, in a further preferred embodiment ofthe invention (not illustrated) the end section may be pivotally connected to the stage to act under gravity.

Referring now to Figure 5, the bridge 20 of Figures 1 and 2 is shown in use in an alternative application, that is, bridging between two trains stopped side-by-side on adjacent tracks.

As canbe seen, the bridge is shown in an extendedpositionbetween two parallel train carriages 12, 44. In the event of abreakdown of one ofthe train carriages, for example, the bridge 20 can be used across the gap between the two carriages 12, 44, to provide a gangway for passengers between the trains 12, 44. Connection means (not shown), for example a releasable clamp or lock mechanism, can be provided to secure the stage 22 on to the opposing carriage. hi use, the bridge 20 is deployed across the gap and received on the doorstep ofthe adjacent carriage 44, for example. Packer means (not shown) areprovided, which canbepositioned under the leading end ofthe stage 22, in cases where the level ofthe "receiving" carriage 44 is sufficiently lower than the "bridging" carriage 12. Thepacker means may take the form ofblocks, for example.

Alternatively, if the opposmg train is also fitted with a bridge in accordance with the invention, the end ofthe stage 22 is receivable in a corcespondingly formed housing 34 on the opposing train 44.

If the stage 22 is not ofa length sufficient to bridge the gap between the two trains 12, 44, an extension (not shown) can be fitted manually to the stage 22 to be receivable on the train 44. Alternatively, the stage maybe attachable to a similar stage extended from aparallel train 44, for example halfway between the two carriages 12, 44.

A modified embodiment ofa bridge in accordance with the invention is shown in Figures 6 and 7, indicated at 50.

Only the right hand end ofthe bridge 50 is illustrated, located between the floor panel 52 and underframe 54 of a train carriage, in transverse alignment with a pair of opposmg doorways (not shown).

The bridge 50 consists ofa one piece stage 56, which is located within a housing 58. The housing 58 includes a pair of guide members, upper guide member 60 and lower guide member 62, on either side ofthe housing 58, between which the stage 56 is moveably supported.

The stage 56 is moveable between an inoperative position in which the stage 56 is contained within the housing 58, as showninFigure 6, and an operative position in which the stage 56 extends from the housing 58, as shown in Figure 7, by way of example. The stage is reciprocable between an operative position on either side ofthe housing 58, as described with reference to the previously described embodiments. A threshold plate 64 is provided on the upper surface ofthe housing 58, in the area adj acent the carriage doorways (not illustrated) one on either side ofthe housing 58. The threshold plate 64 is substantially flush with the floor panel 52.

A cover flap 66 is bingeably connected to the end ofthe threshold plate 64, to the right as viewed in Figures 6 and 7, for movement about an axis 68. The cover flap 66 is moveable between a closure position, in which the end ofthe housing 58 is concealed behind the cover flap 66, as shown in Figure 6, and a transition position, in which the cover flap 66 forms a transition between the threshold plate 64 and the stage 56, as the stage 56 is extended from the housing 58, as can be seen in Figure 7, by way of example.

The purpose ofthe cover flap 66 in the closure position is to inhibit the ingress of moisture and particles into the housing, which may comprise the integrity ofthe stage 56. h the transition position, the cover flap 66 provides a relatively smooth means of access between the threshold plate 64 and the stage 56, which is of particular advantage for wheelchair users, for example.

As can be seen from Figures 6 and 7, the ends ofthe stage 56 are of a reduced depth and each include a roller 70. Each roller 70 has a diameter greater than the reduced depth ofthe stage 56, to enable the roller to come into contact with the surface to which the stage 56 is deployed, to facilitate ease of deployment or retraction ofthe stage 56 once in contact with the surface.

A seal (not illustrated) may be provided on the rear face ofthe cover flap 66, for complimentary engagement with a seal provided on the train underframe 54 or on the housing 56_? to seal the housing 56 from one end in the closure position.

Figure 8 shows a bridge in accordance with the invention, indicated at 72, consisting ofa stage 74 which is reciprocable, in the manner described above, within ahousing 76. The housing 76 consists of apair of channels 78 of substantially u-shaped cross section, eachpositioned on one side in an opposing relationship to one another, which are secured at a predetermined spacing from one another on a base plate 80. A nylon block 81 is provided on either side ofthe housing 76, connected to the lower arm of each channel 78 and extending substantially along the length ofthe housing 76, as a guide on which the stage 74 is slidably supported, hi use, the upper arm of each channel 78 serves as an upper guide member for the stage 74, for sliding co-operation with a roller (not shown) provided at either end ofthe stage 74, substantially as described above.

The stage 74 consists ofa central panel 82 having a pair of side members 84, each extending longitudinally along the length ofthe central panel 82. Each side panel 84 includes a recess 86 in which the end of aplurality of substantially J-shaped upstands 88 are received, only two of which are visible in Figure 8. Each upstand 88 consists ofa substantially curved endportion 90 and a straiglit ann portion 92, which is movable between an operative position in which the arm portion 92 extends substantially perpendicular to the longitudinal axis of the bridge 72, as shown on the right hand side of Figure 8, and an inoperative position in which the armportion 92 is substantially parallel with the upper surface ofthe stage 74, as shown on the left hand side of Figure 8.

For the purpose of description, the recess 86 in each side panel 84 will now be described in detail, with respect to the side panel 84 as shown enlarged in Figure 9.

From the right as viewed, the recess 86 includes a substantially downwardly depending knuckle formation 94 having an arcuate profile, and an undercut surface 96 which terminates at a rectangular return surface 98. Recess 86 further includes a straight bottom surface 100 and a curved transition surface 102, the recess 86 ending at a vertical straight portion, to the left as viewed. The upstands 88 are introduced into arespective recess 86, from one end ofthe stage 74.

Movement of an upstand 88 from the inoperative position on the left of Figure 8 as viewed to the operative position on the right as viewed in Figure 8 is as follows:

The free end ofthe arm portion 92 is lifted away from the upper surface ofthe stage 74, causing rotation ofthe curved end portion 90 about the arcuate surface ofthe knuckle formation 94. As the free end ofthe armportion is continued to be lifted, the free end ofthe curved end portion 90 comes into contact with the undercut surface 96. At this point, the upstand 88 falls within the recess 86, the curved endportion 90 contactmg the curved transition surface 102 ofthe recess 86. The curved end portion 90 then moves along the transition surface 102 in the direction ofthe rectangular return surface 98. The junction between the curved end portion 90 and the armportion 92 on the internal side ofthe upstand 88 levers against the arcuate surface ofthe knuckle formation 94, with continued movement ofthe free end ofthe arm portion 92 away from the upper surface ofthe stage 74. The leverage of the junction between the arm portion 92 and the curved end portion 90 with the knuckle formation 94 causes the free end ofthe curved endportion 90 to pop into frictional abutment with the top corner ofthe rectangular return surface 98, as shown on the right in Figure 8, to lock the armportion 92 ofthe upstand 88 in aposition extending upwardly, substantially perpendicular to the upper surface ofthe stage 74.

To move the upstand 88 from the operative position to the inoperative position, the reverse procedure is carried out.

A bridge in accordance with the above aspect ofthe invention will have application wherever a transitional access means is required between two spaced apart surfaces, for example on all fonns of wheelchair access ramps. For instance, the invention could be used for wheelchair access to or from a building, or for wheel chair access to or from a bus.

Figures 10 to 13 show still a further embodiment of a bridge in accordance with the invention, having a housing 110 in which a stage 112 is retractable, as described with reference to the previously described embodiments. For the purpose of illustration, onlythesidepanel 113 ofthe stage 112 is shown.

The stage 112 is shown in the stowed position on the housing 110 inFigure 10, only one corner from one end ofthe housing 110 being illustrated.

A flipper 114 is mounted on the housing 110 by apin 116 about which the flipper 114may be rotated. Four such flippers 114 are provided on the housingl 10, one at each comer, i.e. on either side ofthe housing 110 adj acent both ends ofthe housing 110, for preventing removal ofthe stage 112 fromthehousing l lO, inuse. The flipper 114 includes apair of arms 118, 120disposedat right angles to one another and a rectangular formation 122 in the area of the junction ofthe aims 118, 120.

With the stage 112 in the stowed position shown in Figure 10, the flipper is positioned with arm 118 in abutment with the side wall 124 ofthe housing 110. The other arm 120isperpendicularto thesidewall 124, with the spacing between the two arms 118, 120 facing out ofthe housing 110, to the right as viewed, so that the roller 126 at the right hand end ofthe stage 112 is positioned between the arms 118, 120.

The stage 112 is deployable from either end ofthe housing 110. Figure 11 shows the stage 112 in an extended position from the right hand end ofthe housing 110. The stage 112 is restricted from being withdrawn from the housing 110 by the flipper 114. Movement ofthe roller 126 on the left hand end ofthe stage 112 is limited by arm 120 ofthe flipper 114. Since the ann 118 is in contact with the side wall 124 ofthe housing 110, the flipper 114 is unable to rotate about pin 122, anticlockwise as viewed.

Figure 12 shows the stage 112 in a deployed position to the left of the housing 110, as viewed. As can be seen, the roller 126 at the right hand end ofthe stage 112 is to the left ofthe flipper 114, and the arms 118, 120 ofthe flipper 114 are in an orientation at 90 degrees rotation clockwise to the position ofthe arms 118, 120 in Figure 10 and 11. As the stage 112 is moved to the left as viewed from the position in Figure 10, the roller 126 causes the flipper 114 to rotate clockwise about pin 116, to enable the roller 126 to pass beyond the flipper 114.

An aperture 130 is provided in the side wall 124 ofthe housing 110 adj acent the flipper 114, to enable the rectangular portion 122 ofthe flipper to rotate about the pin 116, as shown inFigure 13. A metal plate spring 132 is mounted across the aperture 130, which is secured in place by rivets 134. As the flipper 114 rotates, the spring 132 flexes to allowmovement ofthe rectangular portion 122. Progressively, as the flipper 114 rotates passed 45 degrees clockwise from the position in Figure 10 , for example, the spring 132 pushes back against the flipper 114 to ' flip ' the arms 118, 120 into the position shown in Figure 12. If the stage is returned to the stowed position of Figure 10, the reverse ofthe above procedure takes place.

It will be appreciated that each ofthe four flippers 114 are arranged appropriately on the housing 110 to enable or restrict the movement ofthe stage 112 between the stowed position and an extended position from a respective end ofthe housing 110.

It will be understood that the invention provides a simple alternative to known access means for train carriages or vehicles. The invention is advantageous primarily in that it can be installed in the floor panel ofa train carriage or vehicle, and does not require storage space within the passenger compartment ofthe carriage or vehicle. The invention can be operated simply and efficiently.

The upstands referred to throughout the specification are intended to conform to the requirements ofthe Rail Vehicle Accessibility Regulations 1998 No. 2456.

It will be appreciated that the term "train" throughout the specification is intended to encompass any vehicle capable of travel along rails, such as a tram for example. Furthermore, it will be understood that references throughout the specification to a "vehicle" is intended to encompass all forms of passenger vehicle such as a coach or a bus.

Claims

1. A bridge (20, 50, 72) for providing access to or from a carriage or vehicle comprising a retractable stage (22, 56, 74, 112) movable, in use, between an extended position in which the stage (22, 56, 74, 112) extends laterally ofthe carriage or vehicle, and a stowed position in which the stage (22, 56, 74, 112) does not proj ect from the carriage or vehicle, characterised in that the stage (22, 56, 74, 112) is reciprocable between extended positions on either side ofthe carriage or vehicle.

2. A bridge according to claim 1 , characterised in that the bridge (20, 50, 72) includes a housing (34, 58, 76, 110) in the form ofa cassette, within which the stage (22, 56, 74, 112) is reciprocable.

3. A bridge according to claim 2, characterised in that the housing (34, 58, 76, 110) includes aplurality of guide members (36, 38, 60, 62, 78, 81), the stage (22, 56, 74, 112) being movable within the housing (34, 58, 76, 110) between the guide members (36, 38 , 60, 62, 78, 81).

4. Abridge accordingto claim 3, characterised in that the guide members (36, 38, 60, 62, 78, 81) extend substantially along the length ofthe housing (34, 58, 76, 110).

5. A bridge according to claim 3 or 4, characterised in that the guide members (36, 38, 60, 62, 78, 81) consist ofupper and lower guide members (36, 38, 60, 62, 78, 81)provided on either side ofthe housing (34, 58, 76, 110), between which the stage (22, 56, 74, 112) is slidably supported.

6. Abridge accordingto anyone of claims 2 to 5, characterised in that means (40, 114) are provided adj acent both ends ofthe housing (34, 110), for preventing removal ofthe stage (22, 112) from the housing (34, 110), in use.

7. Abridge accordingto claim 6, characterised in that the means for preventing removal of the stage (22) from the housing (34) consists ofa stop formation (40) provided on the guide members (36, 38) adjacent both ends ofthe housing (34).

8. A bridge according to claim 6, characterised in that the means for preventing removal of the stage (112) from the housing (110) consists ofa flipper (114) provided on either side ofthe housing (110) adjacent both ends ofthe housing (110).

9. A bridge according to claim 8, characterised in that each flipper (114) is mounted on the housing (110) by apin (116), for rotation about the pin (116), and each flipper (114) includes a pair of arms (118, 120) disposed at right angles to one another, for limiting movement ofthe stage (112) in an extended position.

10. A bridge according to any one of claims 2 to 9, characterised in that means (42, 66) are provided at both ends ofthe housing (34, 58), for providing a transition between the housing (34, 58) and the upper surface ofthe stage (22, 56) in the extended position.

11. A bridge according to claim 10, characterised in that the means for providing a transition between the housing (34, 58) and the upper surface ofthe stage (22, 56) consists ofa flap

(42, 66) hingeably connected to the housing (34, 58), for hingeable movement as the stage (22, 56) is extended or retracted.

12. A bridge according to any preceding claim, characterised in that each end ofthe stage (22) includes a spring-lo aded pivotably connected end section (24), for supporting the stage (22) as the stage (22) is extended or retracted.

13. A bridge according to any preceding claim, characterised in that the stage (22, 74) includes an upstand (26, 88) positioned substantially along the length of each longitudinal edge of the stage (22, 74), for inhibiting movement of a wheeled vehicle, such as a wheelchair, over a longitudinal edge ofthe stage (22, 74).

14. Abridge accordingto claim 13, characterised in that each upstand (26, 88) ismovable between an operative position in which the upstand (26, 88) projects upwardly from the stage (22, 74), and aninoperativeposition in which the upstand (26, 88) is substantially parallel with the upper surface ofthe stage (22, 74).

15. A bridge according to claim 14, characterised in that each upstand ( 88) is J-shaped having a straight arm portion (92) and a curved endportion (90), and that the stage (74) includes at least one recess (86) for receiving the curved end portion (90) of each upstand (88).

16. A bridge according to claim 15 , characterised in that the or each recess (86) has an internal profile which is shaped for operatively receiving an upstand (88), for movably locking the upstand (88) in the extended position.

17. A bridge according to claim 16, characterised in that the upper portion ofthe internal profile includes aknuckle formation (94) having an arcuate profile, and an undercut surface (96) which terminates at a rectangular return surface (98) and the lowerportion ofthe internal profile includes a curved transition surface (102), for operative interaction with the upstand (88) during movement ofthe upstand (88) between the operative and inoperative positions.

18. Abridge accordingto anypreceding claim, characterisedinthatroUermeans (70, 126) are provided at both ends ofthe stage (22, 56, 74, 112), to reduce frictional contact between the end of stage (22, 56, 74, 112) and surface to which the stage (22, 56, 74, 112) is intended to be deployed, during the reciprocable movement ofthe stage (22, 56, 74, 112).

19. Abridge accordingto anypreceding claim, characterised in that the bridge (20, 50, 72) is power-operated.

20. A bridge for providing wheelchair access comprising a stage (74) having at least one upstand (88) to inhibit movement of a wheeled vehicle over a side ofthe stage (74), characterised in that the or each upstand (88) is movable between an operative position in which the upstand (88) projects upwardly from the stage (74), and an inoperative position in which the upstand (88) is substantially parallel with the upper surface ofthe stage (74).

21. A bridge accordingto claim 19, characterised in that the or each upstand (88) is J-shaped having a straight armportion (92) and a curved endportion (90), and that the stage (74) includes at least one recess (86) for receiving the curved endportion (90) ofthe or each upstand (88).

22. Abridge accordingto claim20, characterised in that the or each recess (86) has an internal profile shaped for operatively receiving the or each upstand (88), for movably locking the upstand (88) in the extended position.

23. A bridge according to claim 22, characterised in that the upper portion ofthe internal profile includes aknuclde formation (94) having an arcuate profile, and an undercut surface (96) which terminates at a rectangular return surface (98) and the lower portion ofthe internal profile includes a curved transition surface (102), for operative interaction with the upstand (88) during movement ofthe upstand (88) between the operative and inoperative positions.

24. A carriage or vehicle whenever provided with a bridge as claimed in any one of the preceding claims.