The invention is in the field of devices aiding the handi- capped, and particularly wheelchair passengers, to board and deboard vehicles, including commercial vehicles and private vans. Several styles of these devices are in use, and those developed by the inventor of the device disclosed herein are of the type wherein a fold-out step panel arrangement is used in which the step horizontal surfaces and risers are hinged together. When used as a step, the panels are folded into a step configuration, but can subsequently be used as a platform by extending the panels out horizontally on a carriage structure that also, once extended, can be hydraulically driven upwards or downwards to raise or lower a passenger in a wheelchair on the platform between the vehicle surface and the sidewalk or boarding plat¬ form.

Patents issued to the inventor and co-workers on this type of alternate step/platform lift mechanism include U.S. Patent Nos. 4,081,091 issued 03/28/78; 4,027,807 issued 06/07/77; and

4,176,999 issued 12/04/79. Additionally, a pending application, Serial No. 06/268,466 is a contϊnuation-in-part of a Patent Cooper¬ ation Treaty Application which was in turn a continuation-in-part of U.S. Application No. 4,251,179.

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These lifts work quite well and have been very successful in the marketplace. Their primary application lies in transit buses, private vans, and the transit company mini-buses that are used in some cities as an accommodation to the handicapped in place of equipping all of their buses with the wheelchair lift.

These lifts have been constructed to define two steps intermediate the vehicular floor and the passenger platform or sidewalk, which is ideal for buses and vans. However, in some trolleys and other rail vehicles, the distance between the vehicle floor and passenger platform is sufficiently great that another step is required, so that three steps are ideal.

Because the forerunner two-step lift structure has been engineered virtually to perfection, ideally, rather than re- engineering that basic concept to incorporate yet a third step, a better solution would lie in the provision of an auxiliary step to use in conjunction with the two-step lift. Summary of the Invention

The instant invention precisely fulfills the above stated need and constitutes an auxiliary, or third, step mechanism which is used above the upper of the two steps of the existing step platform structure. The auxiliary step is more or less independent of the platform mechanism, except that it obviously must be phased in its operation with the platform.

The entire apparatus has three basic modes. The first is the stowage mode in which neither the platform nor the steps are used but the apparatus is gathered up out of the way as far as is possible while the vehicle is in motion. In this mode, the platform mechanism is drawn up close underneath the auxiliary step element, which extends horizontally in its step mode.

In the second mode of operation, steps are defined by the platform apparatus. In this mode, the platform apparatus in its step configuration is lowered beneath the auxiliary step of the instant invention, so that the latter provides the third step up from ground level.

In the third and final configuration, the plat orm structure is in its platformΛift mode. It extends out horizontally beneath the auxiliary step element, and the auxiliary step folds downwardly into the vertical position, while simultaneously a barrier panel swings into the vertical position beneath the auxiliary step element to define a continuous vertical barrier behind the lift structure to wall off what would otherwise be a gaping void between the floor of the train and the platform through which a handicapped person might well slip, all or in part.

The auxiliary step mechanism is more or less self- contained, being mounted in a rectangular frame which attaches onto the rear of the existing towers of the platform structure.

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This frame mounts a linear actuator which drives a yoke, simul¬ taneously moving the auxiliary step element itself and the hori¬ zontal barrier with which it cooperates in the barrier mode, between the modes of operation. Brief Description of the Drawings

Figure 1 is an elevation section of the auxiliary step mechanism in place behind a lift,, shown in the stow position;

Figure 2 is the plan form view of the apparatus of Figure

1; Figure 3 is an elevation section of the step mechanism in step position;

Figure 4 is a plan view of the apparatus in the mode shown in Figure 3j

Figure 5 is an elevation section of the step mechanism in its lift or platform position; and,

Figure 6 is a plan form view of the apparatus extended as in Figure 5. Detailed Description of the Preferred Embodiment

As indicated above in the background, the instant invention is used in conjunction with the platform lift structure which is the subject of the patents indicated and the pending application.

Insofar as the structure is described in those patents and the application, it is of course not part of this invention, and so the

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platform lift will be described only generally here, with the indicated patents and patent application being hereby incor¬ porated by reference for the details of construction of the lift. Generally speaking, the lift is mounted between a pair of upright towers 10 which are themselves mounted in the well of the passenger vehicle. A carriage 12, best seen in Figures 1, 3, and 5, moves up and down between the two towers, with control functions and hydraulic power being provided through junction box 14. The carriage moves from the stowed position shown in Figure 1, down to a step mode indicated in Figure 3 and 4, and finally into a platform mode, the lower position of which is illustrated in Figures 5 and 6 wherein the platform is aligned with the sidewalk or boarding area, the raised position being shown in phantom. In addition to the up and down motion, the carriage moves out and back by virtue of its being slidably mounted on rails 16, best seen in Figure 5. These rails are fixedly mounted on the elevator structure operated by the towers, and the carriage slides in and out on the rails as the rails move up and down. In Figure 1, the carriage is completely retracted in the stowed mode. In Figure 2, the carriage moves out partially to bring forward the step/platform panels 18, which are hinged together end to end in accordian fashion. As the carriage moves

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out, the trapezoidal cross section of the panels changes to a rectangular cross section as indicated in Figure 3, with the end plates 20 now being forwardly displaced with respeet to the stair outline as can be seen from their trapezoidal seals 22. Extending upwardly from these end plates are handrails 24, the upper portion of which is visible in the plan form views of Figures 2, 4, and 6.

Moving to Figure 5, the carriage is extended completely out, bearing the rails 16 in their rear portions, and defining an extended platform 26 instead of the rectangular stair or steps defined by the step/platform panels 18 in Figure 3.

The retractable step mechanism forming the essence of the invention includes a step element 28 which, as seen in Figures 1 and 3, extends forwardly beneath the outermost edge of the passenger support surface 30, ordinarily the floor, of the passenger vehicle. When in its retracted mode as shown in Figure 5, the step element pivots down generally flushly with the portion of the vehicle immediately beneath the outermost edge of the floor 30. The invention is designed to be rather easily added onto the platform lift structure, and is mounted in a frame that is generally U-shaped, which is best seen in Figures 2, 4, and 6 as comprising a rear crossbeam 32 and a pair of forwardly extending side beams 34. These beams may be in the form of open channels,

as can be visualized by simultaneous reference to Figures 1 and 2. The channels open outwardly on all three sides of the U-shaped frame.

A re-enforcing box beam 36 spans between the side beams in front of the crossbeam, and strength plates 38 are mounted at the junction of the beams as shown.

The forward ends of the side beams 34 terminate inside

L-channels 40, which define uprights between which the step element 28 is pivotally mounted at 42. Also mounted ^' between these uprights is a panel 44, pivoted at 46 and comprising elongated side supports 48 which extend rearwardly to. mount panel element 50 and dogleg forwardly to define arms 52 which are slotted as indicated at 54. These arms engage arms 56, which are actually flanges depending from the edges of the step element 28. The engagement is by means of a pivot pins 58 which pass through arms 56 and ride in the slots 54. Together the arms and pivot define a linkage mechanism causing the step element and panel to move in unison.

The pivot pins 58 project from the arms or prongs 60 of a yoke 62 which is mounted centrally of its crossbar 64 on the forward end of a linear actuator 66. This actuator could be hydraulic, although the actuator illustrated utilizes a plunger shaft 68 which is driven out of a casing 70 by means of rack and worm gear arrangement powered by an electric motor 72.

The linear actuator is pivotally mounted at 74 to a bracket 76 which clamps onto the box beam 36 mounted in front of the crossbar 32.

It can be seen from the drawings and in conjunction with the above description that as the linear actuator 66 extends, the step element 28 and panel 44 swing into the step mode shown in Figure 1 wherein the step element extends forwardly and the panel is swung rearwardly in a stowed positon out of the way of the other elements. As the actuator is retracted, the pins 58, which extend outwardly from the ends of the prongs 60, draw the step element 28 down into the vertical position shown in Figure 5, with the panel 44 concomitantly swinging forward into the vertically aligned position also shown in Figure 5 to define a substantially solid vertical barrier occupying the entire space above the plat¬ form 26 and below the short wall panel 78 that depends from the edge of the vehicle floor. The panel and step thus have a dual function, first to provide a third step above the two steps provided by the platform lift, and second to define the vertical barrier which is necessary for the safety of handicapped pas¬ sengers who are utilizing the lift.

A pair of lift locks 80 are mounted on opposite sides of the frame, being mounted on the outsides of the side beams 34 and operated by the side beams interiorly to lock the carriage

12 in its stowed positon as shown in Figure 1.

The instant invention can be utilized anywhere there is a need for a retractable step which converts into a vertical barrier extending beyond the area of the step itself, although clearly it is intended for use with the platform lift and is particularly adapted for the platform lift inasmuch as it conveniently moves from the step mode into the vertical barrier mode in which it covers the wide space normally left above the platform when the unit is in its platform mode. In addition to the transit type vehicles in which the platform lift mechanism is raised for storage during transit, the platform lift can be used on a motor home or recreational vehicle in which the step structure is deployed as a platform for raising and lowering, but if not lifted is in its step mode. Mounted on a stationary vehicle, the auxiliary step will bridge the distance between floor and ground level where two steps are not enough. The lift will service not only the handicapped, but provides a lift for supplies and equipment as well.

While the preferred embodiment of the invention has been described, other modifications may be made thereto and other embodiments may be devised within the spirit of the invention and scope of the appended claims.