GB2055705A

GB2055705A - Retractable step assembly for motor vehicles

Info

Publication number: GB2055705A
Application number: GB7928010A
Authority: GB
Original assignee: Ford Motor Co Ltd; Ford Motor Co
Current assignee: Ford Motor Co Ltd; Ford Motor Co
Priority date: 1979-08-10
Filing date: 1979-08-10
Publication date: 1981-03-11
Also published as: GB2055705B; DE3026082A1; DE3026082C2

Abstract

A retractable step assembly for a motor vehicle comprises a step (1, 2) mounted on the vehicle body for pivotal movement about a vertical axis (5) between extended and retracted positions by means of a linkage (9, 13) connected to a door (7) so that the step extends and retracts as the door opens and closes. In one embodiment the door is hinged, in another it slides in the first embodiment a sliding connection (14, 15) between the door (7) and the linkage (9) and articulation in the two elements (9, 13) of the linkage causes the step to be more than half extended when the door is half open. In both embodiments the linkage (9, 13) passes through a dead centre as the step approaches the extended position to stabilise the assembly for use. <IMAGE>

Description

SPECIFICATION Retractable step assembly for motor vehicles This invention relates to retractable step assemblies for motor vehicles.

One known retractable step assembly used on motor vehicles such as passenger vans or buses includes a step secured to the vehicle body and arranged for sliding movement on a generally horizontal track between an extended position and a retracted position, and a linkage connecting the step to the vehicle door to move the step between the extended and retracted positions as the door moves between open and closed positions respectively. (British Patent Specification No.

987846 discloses an assembly of this construction).

In use, the tracks of such assemblies are exposed to dirt thrown up from the road surface and can easily become clogged which prevents smooth operation of the step assembly and which may eventually cause permanent damage.

According to the present invention there is provided a retractable step assembly for a motor vehicle comprising a step adapted to be mounted on a vehicle body adjacent an entrance thereto for movement between an extended position and a retracted position, and linkage for connecting the step to the vehicle to move the step between the extended and retracted positions respectively, characterised in that the step is adapted to be mounted on the vehicle body for pivotal movement about a vertical axis.

By mounting the step for pivotal movement about a vertical axis, the use of tracks can be dispensed with, thus improving the durability of the assembly.

The step preferably comprises a tread plate carried by a cantilever arm projecting radially from the pivot axis.

The linkage preferably comprises a bell crank lever mounted on the vehicle for movement about a vertical axis and connected at one end to the step and at the other end to the door so that the assembly may be used with either a hinged door or a sliding door.

Where the assembly is used in conjunction with a hinged door, the said other end of the bell crank lever is preferably mounted for sliding movement in a horizontal track secured to the door. The track may conveniently be provided with a detent, for example a ramped spring, engagable with the end of the bell crank lever to retain the end of the lever in an end position on the horizontal track corresponding to the open position of the door.

Where the step assembly is used with a sliding door, the said other end of the bell crank lever is preferably pivotally connected to one end of an actuating lever the other end of which is pivotally connected to the sliding door.

In order to reduce the vertical space occupied by the assembly the step and the or each lever in the linkage are preferably mounted for movement in horizontal planes. It may be desirable to use a bell crank lever in which the ends of its arms lie in separate horizontal planes so that movement of the step can be accommodated without interference with the linkage.

Advantageously, the linkage lies at or near a dead centre position when the step is in its extended position so that movement of the step during use in its extending position produces little or no movement of the door.

In the preferred embodiment of the invention, the linkage is arranged to move the step through more than half of its travel from the retracted position to the extended position as the door completes half of its travel from its closed to its open position so that sufficient of the step is exposed for use even though the door is not completely open, as, for example where the vehicle is standing alongside an obstruction.

Two embodiments of the invention will now be described by way of example only, with reference to the accompanying schematic drawings, in which: Figure 1 is a plan of a first embodiment of the invention showing the step assembly in its extended position (full lines) and retracted position (chain-dotted lines); Figure 2 is a plan of the embodiment of Fig. 1, Fig. 1 showing the step assembly in its retracted position; Figure 3 is a partial elevation of the embodiment of Figs. 1 and 2 taken along line Ill-Ill of Fig. 1; Figure 4 is a view similar to Fig. 1 showing a second embodiment of the invention in its extended position (full lines) and retracted position (chain-dotted lines); Figure 5 is a partial elevation of the embodiment of Fig. 4 along arrow A of Fig. 4;; Figure 6 is a partial elevation of the embodiment of Fig. 4 along line VI-VI; Figure 7 is a partial elevation of the embodiment of Figs. 4 and 5 taken along line VIl-VIl and Figure 8 is a view similar to Fig. 4 showing the assembly in its retracted position.

Referring to the drawings, the step assembly of Fig. 1 comprises a tread plate 1 carried by a Y-shaped cantilever arm 2 which is mounted on a body member (see Fig. 3) 3 of a vehicle by means of a vertical pivot pin 4 and two vertically spaced self-lubricating bushes 6. The arm 2 extends radially from the vertical axis 5 of the pin 4 and is pivotable about the axis 5 between an extended position, in which the tread plate 1 lies outwardly of the body of the vehicle adjacent the threshold of a doorway into the passenger compart ment of the vehicle, and a retracted position, in which the tread plate 1 lies beneath the body of the vehicle.

Movement of the tread plate 1 is effected by a linkage connecting the tread plate 1 to a door 7 which is hinged to the side walls 7a of the vehicle for movement about a vertical axis 8.

The linkage comprises a bell crank lever 9 pivotally mounted on the body of the vehicle for movement in a horizontal plane about a vertical axis 1 0. The bell crank lever 9 comprises two lever arms 11, 1 2 fixed to a vertical shat rotatably mounted in a bearing fixed to the vehicle body. The two lever arms 11, 1 2 are vertically off set from each other so that their free ends lie in adjacent horizontal planes.

The free end of one lever arm 11 is pivotally connected to one end of an actuating lever 1 3 the other end of which is coupled to a tongue on the edge of the tread plate 1 by a vertical pivot pin. The free end of the other lever arm 1 2 is connected to a roller 14 which is slidably received in a horizontal track 1 5 mounted in the door 7. A leaf spring 1 6 is secured to the track 1 5 and includes a ramp 1 7 which projects into the track 1 5 through a hole in one wall of the track 1 5 adjacent one end thereof.

In use, when the door 7 is closed, the ball joint 14 lies towards the end 1 spa of the track 1 5 remote from the spring 16. As the door moves about the axis 8 towards the open position, the roller 1 4 slides along the track 1 5 and the lever arm 11 is rotated about the axis 10. This movement is followed by the lever arm 1 2 and is transferred therefrom to the tread plate 1 by the actuating lever 1 3.

Since the pivot axis 10 is off-set from the hinge axis 8 of the door, and a sliding connection exists between the door 7 and the free end of the lever arm 12, the initial movement of the door towards the open position is amplified so that when the door is half open the lever arm 1 2 has completed twothirds of its travel (as indicated by the dotted line 1 2'). Moreover, since the actuating lever 1 3 which couples the lever arm 1 2 to the tread plate 1 is brought into alignment with the lever arm 1 2 as the door approaches the open position, the tread plate 1 has completed approximately 87% of its travel (as indicated by the dotted line 1') when the door 7 has completed 50% of its travel.This allows the tread plate 1 to be used even when the door is not fully open.

As the tread plate 1 approaches its extended position the lever arm 11 and the actuating lever 1 3 pass throug a dead centre position in which the lever arm 1 < and the lever 1 3 are aligned and, in the extended position, the arm 11 and lever 1 3 lie marginally past the dead centre position. In this position, movement of the tread plate 1 caused by foot pressure during use of the assembly produces little or no movement of the door 7 so that the assembly remains stable during use.

Referring now to Figs. 4 to 6, a step assembly suitable for use in a vehicle having a sliding door is illustrated. Parts similar to those of Figs. 1 and 2 have been given like reference numerals. The tread plate 1 and cantilever arm 2 and their mounting on the vehicle body are identical to those shown in Figs. 1 and 2. The door 7 is slidable along a track (not shown) along a horizontal path of travel 8 running generally parallel to the side wall 7a of the vehicle body.

The linkage connecting the tread plate 1 to the door 7 comprises a bell crank lever 9 formed as an integral pressing and mounted on the vehicle body for pivotal movement about a vertical axis 1 0. As best seen in Fig.

4, one of the lever arms 1 2 is bent dswn- wardly so that its end lies in a lower horizontal plane than the end of the other lever arm 11 to avoid interference between the parts of the linkage in use.

The lever arm 11 is pivotally connected to an actuating lever 1 3 which is in turn con nected to the tread plate 1 in the same way as the embodiment of Fig. 1. The other lever arm 1 2 is pivotally connected to one end of a further actuating lever 18, the other end of which is pivotally connected to a bracket 1 9 fixed to the lower edge of the door 7 (see Fig.

6).

In use, as the door 7 is opened, the lever 1 8 follows the movement of the door 7 and rotates the bell crank lever 9 about the verti cal axis 10, and this movement is transferred to the tread plate 1 by the actuating lever 1 3.

Unlike the embodiment of Figs. 1 and 2, when the door 7 reaches the mid point of its travel (indicated by dotted lines) the tread plate 1 has also completed 50% of its travel.

Amplification of the initial movement of the door 7 is unnecessary in sliding door arrange ments since the sliding door can be opened fully even when the motor vehicle is standing alongside an obstruction.

As the door 7 approaches its fully open position, the tread plate 1 also approaches its extended position and the lever arm 11 of the bell crank lever 9 and the actuating lever 1 3 pass through a dead centre position in which the arm 11 overlies the lever 1 3 and in the 'extended position of the tread plate 1, the arm 11 and lever 1 3 lie marginally past this position. As a result, the assembly remains stable during use.

Claims

1. A retractable step assembly for a motor vehicle comprising a step adapted to be mounted on a vehicle body adjacent an en trance thereto for movement between an ex tended position and a retracted position, and a linkage for connecting the step to the vehicle to move the step between the extended and retracted positions as a door for the entrance moves between opened and closed positions respectively, characterised in that the step is adapted to be mounted on the vehicle body for pivotal movement about a vertical axis.

2. A step assembly according to Claim 1 wherein the step comprises a tread plate carried by a cantilever arm projecting radially from the pivot axis.

3. A step assembly according to Claim 1 or Claim 2 wherein the linkage comprises a bell crank lever adapted to be mounted on the vehicle body for movement about a vertical axis, and connected at one end to the step and adapted at its other end for connection to a vehicle door.

4. A step assembly according to Claim 3 wherein the said other end of the bell crank lever is mounted for sliding movement in a horizontal track adapted to be mounted in a door hinged to the vehicle body.

5. A step assembly according to Claim 3 wherein the said other end of the bell crank lever is pivotably connected to one end of an actuating lever the other end of which is adapted for pivotable connection to a sliding door mounted on the vehicle body.

6. A step assembly according to any one of Claims 3 to 5 wherein the ends of the bell crank lever lie in adjacent horizontal planes.

7. A step assembly according to any one of Claims 1 to 6 wherein the linkage lies at or near a dead centre position when the step is in its extended position.

8. A step assembly according to any one of Claims 1 to 7 wherein the linkage is arranged to move the step through more than half its travel from the retracted position to the extended position as the door moves through half its travel from the closed position to the open position.

9. A step assembly for a motor vehicle substantially as hereinbefore described and as illustrated in Fig. 1 or Fig. 3 of the drawings.

1 0. A motor vehicle comprising a body having an entrance, a door for the entrance mounted on the body and a step assembly according to any one of Claims 1 to 9 mounted on the body adjacent the entrance and operably connected to the door.