Patent Description:
Industrial vehicles like trucks are equipped with boarding steps to help the truck driver, or passenger, get into the cabin of the truck. Usually, the boarding steps are installed on the side of the truck, between the front wheel and the front bumper, approximately at the height of the front bumper. Since the steps can't protrude from the side of the truck, a recessed area is formed on the side of the truck and the steps are disposed in this recessed area. This recessed area has to be deep enough to accommodate steps of sufficient depth to be safe and comfortable to use. Such installation has several drawbacks. First, the step and the frame of the entry door are almost in the same vertical plane. Therefore, access is not particularly easy as users generally feel too close from the door, making access impractical. Another drawback is that the recessed area alters the otherwise sleek shape of the side of the cabin. A consequence of this recessed area is increased aerodynamic losses and increased drag coefficient. Furthermore, the recessed area is basically an empty space except for locating the steps, and it would be beneficial to be able to arrange some components in this area. Document <CIT>, disclsoes a telescopic boarding step member comprising a footrest attached to an inner tube which can slide inside a fixed step member, so that the boarding step member can be deployed or retracted for vehicle ingress/egress. The fixed step member is a hollow sleeve.

It would therefore be useful to have a step assembly that doesn't need to be installed in a recess of the side of the truck.

To achieve this goal, it is proposed to provide a collapsible step as defined by the features of claim <NUM>.

When the truck is being driven, the collapsible step assembly is in stowed position and doesn't protrude from the side of the truck. When the driver opens his door to get out of the truck, the action of opening the door also deploys a mobile step member which projects out of the surface of the truck and can be used to climb into the cabin. It is not necessary to create a recessed area in order to accommodate one or several fixed steps. The side of the truck can be smooth, therefore drag coefficient can be reduced. Furthermore, access is easier that with a fixed step, because the deployed step can project sufficiently far from the vertical plan of the door. Furthermore, the space usually devoted to the creation of the recessed area can now be used to fit components, like for example an electronic control module for the front headlights.

The following features, can be optionally implemented, separately or in combination one with the others:.

In an embodiment, in the stowed position, the mobile step member is set-back from an external surface of the cabin.

According to another embodiment, in the stowed position, the mobile step member is flush with an external surface of the cabin.

According to an embodiment of the collapsible step assembly, the actuation member is an actuation cable.

An actuation cable makes a reliable mechanical link that can take different shapes and thus can easily be adapted to various configurations.

In an embodiment, the collapsible step assembly comprises:.

and the actuation cable is configured to link the collapsible step member and the check link.

Using the check link of the door to pull the actuation cable allows an actuation of the collapsible step assembly which limits the number of additional parts to be fitted.

According to an embodiment of the collapsible step assembly, the check link is configured for stopping the entry door in a predetermined stopping position, the predetermined stopping position being an intermediate position between a closed position and a fully opened position.

The predetermined stopping position is selected among a set of stopping positions.

In an embodiment, the collapsible step assembly comprises an elastic member configured for moving the collapsible step member from the deployed position to the stowed position in response to a closing of the entry door.

Once the driver has entered the cabin and closes his door, the elastic member brings back the collapsible step member into its stowed position. No action from the driver is necessary.

In an embodiment, the elastic member is a return spring.

For example, the elastic member may be a coil spring.

Alternatively, the elastic member may be a torsion bar.

According to one aspect of the disclosed step assembly, the collapsible step member is configured to slide linearly between the stowed position and the extended position.

A linear stroke of the mobile step member is comprised between <NUM> centimeters and <NUM> centimeters.

In an embodiment of the collapsible step assembly, the collapsible step member reaches the deployed position for an opening degree of the entry door inferior to a maximum opening degree of the entry door.

In an embodiment, the collapsible step member leaves the stowed position for an opening degree of the entry door superior to a minimum opening degree of the entry door.

The opening degree of the entry door for which the collapsible step member leaves the stowed position can be the closed position of the entry door.

The opening degree of the entry door for which the collapsible step member leaves the stowed position can be a position of the entry door different from the closed position of the entry door.

According to the invention, the collapsible step assembly, the collapsible step member comprises:.

and the mobile step member is configured to be moved along a translation axis when the collapsible step member is moved from the stowed position to the deployed position.

According to an embodiment of the collapsible step assembly, a rate of increase of a position of the mobile step member is proportional to a rate of increase of an opening degree of the entry door, at least for a fraction of a movement stroke from the stowed position to the deployed position.

According to the invention the following is included in the collapsible step assembly:.

This arrangement provides a simple and sturdy structure.

The upper surface of the fixed step member, of the load bearing element and of the mobile step member forms a support surface for the foot of a user. The translation of the elements between them allows a deployment of the collapsible step assembly.

In an embodiment, the first translation shaft and the second translation shaft are offset one from the other.

In an embodiment, the first translation shaft may be identically sized as the second translation shaft.

According to an embodiment of the collapsible step assembly, the fixed step member comprises two first translation shafts extending in a direction parallel to the translation axis and the mobile step member comprises two second translation shafts extending in a direction parallel to the translation axis, one first translation shaft and one second translation shaft being arranged alternately along a direction of extension of the fixed base plate.

Having two pairs of translation shafts provides a natural stability and spreads the efforts, minimizing maximum efforts.

The two first translation shafts and the two second translation shafts may be coplanar.

Alternatively, the two first translation shafts and the two second translation shafts can be in different parallel planes.

In an embodiment, the two first translation shafts are identically sized.

In an embodiment, the two second translation shafts are identically sized.

For example, a diameter of the first translation shaft is comprised between <NUM> millimeters and <NUM> millimeters.

Also for example, a diameter of the second translation shaft is comprised between <NUM> millimeters and <NUM> millimeters.

The distance between the direction of extension of the two first translation shafts may be comprised between <NUM> centimeters and <NUM> centimeters.

In an embodiment, the direction of extension of the fixed base plate is perpendicular to the translation axis.

According to an embodiment of the collapsible step assembly, the collapsible step assembly comprises a plurality of load bearing elements, each load bearing element comprising :.

The loading bearing elements may be identical.

In an embodiment, a length measured in the direction of the translation axis of the first reception hole is comprised between <NUM> millimeters and <NUM> millimeters.

In an embodiment, a length measured in the direction of the translation axis of the second reception hole is comprised between <NUM> millimeters and <NUM> millimeters.

These values provide adequate resistance and adequate contact pressure between parts.

According to an embodiment, the collapsible step assembly comprises a scissor mechanism linking together the fixed step member, the load bearing elements and the mobile step member.

In an embodiment, a first scissor mechanism is disposed at a first axial end of the fixed step member, of the load bearing elements and of the mobile step member.

In an embodiment, an articulation axis of a pair of linkages is located on a load bearing member.

In an embodiment, an articulation axis between a linkage from one pair of linkages and a linkage from the consecutive pair of linkages is located within a load bearing member.

In an embodiment, a second scissor mechanism is disposed at a second axial end of the fixed step member, of the load bearing elements and of the mobile step member.

Having one scissor mechanism at each axial end of the elements provides a better guiding of the mobile elements.

The disclosure also refers to a truck comprising a collapsible step assembly as described above, in which the actuation cable links the collapsible step member and an entry door of the cabin,
and in which the collapsible step member is moved from the stowed position to the deployed position by the actuation cable in response to an opening of the entry door.

In an embodiment, the translation axis makes an angle comprises between <NUM>° and <NUM>° with a transversal axis of the truck.

Alternatively, the translation axis can make an angle larger than <NUM>° with a transversal axis of the truck.

The access to the cabin is made easier because more room is made available between the step and the rotation axis of the entry door.

According to an embodiment of the truck, the collapsible step assembly comprises a second collapsible member configured to be moved from the stowed position to the deployed position synchronously with the collapsible step assembly.

According to an embodiment, the truck comprises a first collapsible step assembly as described earlier and a second collapsible step assembly as described earlier. The first collapsible step assembly comprises a first collapsible step member configured to be moved from the stowed position to the deployed position by the actuation cable in response to an opening of a first entry door, and the second collapsible step assembly comprises a second step member configured to be moved from the stowed position to the deployed position by the actuation cable in response to an opening of a second entry door.

In order to make the figures easier to read, the various elements are not necessarily represented to scale. In these figures, identical elements receive the same reference number. Certain elements or parameters can be indexed, i.e. designated for example by first element or second element, or first parameter and second parameter, etc. The purpose of this indexing is to differentiate elements or parameters that are similar, but not identical. This indexing does not imply a priority of one element, or one parameter over another, and their names can be interchanged. When it is mentioned that a subsystem comprises a given element, the presence of other elements in this subsystem is not excluded.

<FIG> refers to a truck <NUM> according to the prior art. In order to access the cabin <NUM> once the entry door <NUM> is opened, a driver of the truck may step on a fixed step <NUM>. This fixed step provides a support at an intermediate height between the level of the ground and the level of the door sill. The step is wide enough, i.e. large enough along the longitudinal direction X, so that both feet of the user can comfortably fit on the step <NUM>. The step <NUM> is also deep enough, i.e. large enough along the transverse axis Y, so that a convenient and steady support is provided. The step <NUM> is housed in a recessed area <NUM> of the side of the truck, having a box-like shape. The presence of this recessed area <NUM> induces sharp angles on the side of the truck <NUM>, which induces a disturbance to the air flow along the side of the truck when the truck is driven.

<FIG> illustrates a collapsible step assembly <NUM> for helping a user entering a cabin <NUM> of an industrial vehicle <NUM>. This collapsible step assembly <NUM> according to the invention comprises:.

and the collapsible step member <NUM> is configured to be moved from the stowed position S to the deployed position E by the actuation member <NUM> in response to an opening of the entry door <NUM>.

The stowed position S of the collapsible step member <NUM> is a non-functional position for the purpose of providing a support for accessing or getting out of the truck. The deployed position E is a functional position of the collapsible step member <NUM>, in which a support is provided for an easy access or exit of the industrial vehicle. The industrial vehicle is a truck in the illustrated example, but the present device can also be used in other types of industrial vehicles.

The entry door <NUM> of the truck <NUM> is configured for swiveling between a closed position C and a fully opened position O. The entry door is fixed to the frame of the cabin by several hinges, not represented.

When the truck is moving, the collapsible step assembly <NUM> is in stowed position S and doesn't protrude from the side of the truck <NUM>. When a user opens the entry door <NUM> to get in or out of the truck, the action of opening the door <NUM> also deploys the collapsible step member <NUM> so that it forms a supporting surface on which the user may step and transfer its weight to safely reach the ground or the cabin. The collapsible step member <NUM> can be arranged so that it is flush with the surface of the industrial vehicle <NUM> when it is in stowed position S.

In an embodiment, in the stowed position S, the mobile step member <NUM> is flush with an external surface of the cabin. In an embodiment, in the stowed position S, the mobile step member <NUM> is set-back from an external surface of the cabin.

In either case, the side of the truck <NUM> doesn't need any recessed area in order to accommodate one or several fixed steps. The side surface of the truck <NUM> can be smooth, therefore the drag coefficient of the industrial vehicle can be reduced, resulting in better fuel economy or range. The access to the cabin is also made easier than with a fixed step, because the deployed step member can project sufficiently far from the vertical plan of the door. Furthermore, the space usually devoted to the creation of the recessed area can now be used to fit components or subsystems, like for example an electronic control module for the front headlights.

In the illustrated embodiment of the collapsible step assembly <NUM>, the actuation member <NUM> is an actuation cable <NUM>. When the entry door <NUM> is opened, the actuation cable <NUM> is put under tension and the actuation cable <NUM> pulls the collapsible step member <NUM> into the deployed position E. An actuation cable makes a reliable mechanical link that can take different shapes and thus can easily be adapted to various configurations. A single collapsible step assembly can equip various models without modification.

As illustrated on <FIG>, the collapsible step assembly <NUM> comprises:.

and the actuation cable <NUM> is configured to link the collapsible step member <NUM> and the check link <NUM>.

Using the check link of the entry door <NUM> to pull the actuation cable <NUM> allows an actuation of the collapsible step assembly <NUM> which limits the number of additional parts to be fitted.

The truck <NUM>, as illustrated for example on <FIG>, comprises a collapsible step assembly 1a. The actuation cable <NUM> links the collapsible step member <NUM> and an entry door of the cabin <NUM>,
and the collapsible step member <NUM> is moved from the stowed position S to the deployed position E by the actuation cable <NUM> in response to an opening of the entry door <NUM>.

As detailed on <FIG>, the check link <NUM> has an elongated shape similar to a rod. Functionally, the check link <NUM> is a linking rod. The check link <NUM> comprises a first end <NUM> configured to be linked to the entry door <NUM> of the cabin, and a second end <NUM> linked to a first end of the actuation cable <NUM>. The check link <NUM> is pivotably linked to the entry door <NUM> of the cabin. The check link <NUM> is fixed to the entry door <NUM> by a pivot pin. A rotation of the check link <NUM> relatively the entry door <NUM> is allowed. A translation motion of the check link <NUM> relatively the entry door <NUM> is blocked. A section of the check-link <NUM> passes through a bracket <NUM> fixed to the frame of the cabin <NUM>. The actuation cable is contained, near the bracket <NUM>, in a wire holder <NUM>.

The check link <NUM> may be made of sheet metal. The check link <NUM> is horizontal when it is installed in the entry door <NUM> of the industrial vehicle <NUM>.

According to an embodiment of the collapsible step assembly <NUM>, the check link <NUM> is configured for stopping the entry door <NUM> in a predetermined stopping position, the predetermined stopping position being an intermediate position between a closed position C and a fully opened position O. The predetermined stopping position is selected among a set of stopping positions. The set of stopping positions may comprise three stopping positions.

As detailed on <FIG>, the check link <NUM> comprises a friction area <NUM> configured to be pressed by elastic pegs <NUM>. The elastic pegs <NUM> are linked to the bracket <NUM>. The friction area comprises a flat portion <NUM> and a thinned portion <NUM>. The transition between the flat portion <NUM> and the thinned portion <NUM> is made by a slope <NUM>. When the check link <NUM> is moved, the elastic pegs <NUM> slides over the friction area <NUM>. A stopping position is obtained when an elastic peg <NUM> engages into the thinned portion <NUM>. Additional effort is then required to force the pegs <NUM> moving over the slope <NUM> until it reaches another flat portion <NUM>. The tension of the elastic pegs <NUM> and the angle of the transition slopes <NUM> are designed to obtain the targeted resistance to maintain the entry door <NUM> in a stable position, without requiring an excessive effort to then overcome a stopping position. The number of stopping positions is determined by the number of thinned portions <NUM> incorporated in the check link <NUM>. Two stopping positions have been pictured on the example of <FIG>.

The collapsible step assembly <NUM> comprises an elastic member <NUM> configured for moving the collapsible step member <NUM> from the deployed position E to the stowed position S in response to a closing of the entry door <NUM>. The actuation cable <NUM> operates the collapsible step member <NUM> against the biaising action of the elastic member <NUM>, schematically represented on <FIG>. Once the driver has entered the cabin <NUM> and closes the entry door <NUM>, the elastic member <NUM> brings back the collapsible step member <NUM> into its stowed position S. No action from the driver is necessary. Therefore there is risk of driving the truck <NUM> with the collapsible step member mistakenly left in deployed position. The elastic member <NUM> is for example a return spring. The elastic member <NUM> may for instance be a coil spring. Alternatively, the elastic member <NUM> may be a torsion bar.

As illustrated on <FIG>, the collapsible step member <NUM> is configured to slide linearly between the stowed position S and the extended position E. A linear stroke of the mobile step member <NUM> is comprised between <NUM> centimeters and <NUM> centimeters. The direction along which the collapsible step member <NUM> deploys and retracts is indicated by the axis T.

The collapsible step member <NUM> can be made of sheet metal. For example, aluminum and magnesium can be used. The collapsible step member <NUM> may also be made of plastic, for example injected plastic reinforced with glass fibers.

<FIG> illustrates the relationship between the position of the collapsible step member, in vertical axis, versus the opening degree of the entry door <NUM> in horizontal axis. Opening degree is a term equivalent to angular position of the entry door. The closed position C of the entry door is obtained for an opening degree equal to <NUM>. The fully opened position O of the entry door is obtained the opening degree o4. Similarly, the stowed position S is corresponding to position O on the vertical axis, and the deployed position E is corresponding to the maximum of the curve.

In the illustrated embodiment of the collapsible step assembly <NUM>, the collapsible step member <NUM> reaches the deployed position E for an opening degree of the entry door <NUM> inferior to a maximum opening degree of the entry door <NUM>. On the example of part B of <FIG>, the fully deployed position E is obtained when the opening degree of entry door <NUM> reaches the degree o3, and remains constant until the entry door is fully opened, corresponding to opening degree o4.

The collapsible step member <NUM> leaves the stowed position S for an opening degree a of the entry door <NUM> superior to a minimum opening degree of the entry door <NUM>. In the embodiment corresponding to part B of <FIG>, the opening degree of the entry door <NUM> for which the collapsible step member <NUM> leaves the stowed position S is a position o1 of the entry door <NUM> different from the closed position C of the entry door <NUM>. In other words, the deployment of the collapsible step assembly <NUM> begins only once the opening of the entry door <NUM> has already been initiated, and the door has already been opened by a certain amount. This configuration makes the initial opening easier, and the deployment of the collapsible step assembly can make use of the momentum built during the initial phase where the door is free. Deployment of the collapsible step member <NUM> starts when the opening degree of the entry door <NUM> reaches the value marked o1 on part B of <FIG>.

The minimum opening degree of the entry door <NUM> for which the collapsible step member <NUM> leaves the stowed position S can be one of the predetermined stopping positions of the entry door <NUM>. These positions are determined by the position of the position of the thinned portions <NUM> along the check link <NUM>.

In an embodiment corresponding to part A of <FIG>, the minimum opening degree of the entry door <NUM> for which the collapsible step member <NUM> leaves the stowed position S can be the closed position C of the entry door <NUM>. In that case, the deployment of the collapsible step assembly <NUM> begins simultaneously with the opening of the entry door <NUM>.

According to an embodiment of the collapsible step assembly <NUM>, a rate of increase of a position of the mobile step member <NUM> is proportional to a rate of increase of an opening degree of the entry door <NUM>, at least for a fraction of a movement stroke from the stowed position S to the deployed position E. On the example of part B of <FIG>, the feature is present between opening degree o2 and opening degree o3 of the entry door <NUM>. On the example of part A of <FIG>, the feature is present across the full range of opening degree of the entry door <NUM>.

The mechanical structure of an embodiment of the collapsible step assembly <NUM> will now be described.

According to the invention, illustrated on <FIG> and <FIG>, the collapsible step member <NUM> comprises:.

and the mobile step member <NUM> is configured to be moved along a translation axis T when the collapsible step member <NUM> is moved from the stowed position S to the deployed position E.

The fixed step member <NUM> is considered fixed in a referential linked to the frame of the industrial vehicle <NUM>. In other words, the fixed step member <NUM> is stationary with reference to the frame of the industrial vehicle <NUM>. Temporary low-amplitude displacements resulting from vibrations are possible since they are practically unavoidable, without affecting the fixed feature of the fixed step member <NUM>.

<FIG> illustrates the detailed features of the collapsible step assembly <NUM>.

The fixed step member <NUM> comprises a fixed base plate <NUM> and at least a first translation shaft <NUM> extending from the fixed base plate <NUM> in a direction parallel to the translation axis T,
the mobile step member <NUM> comprises a mobile base plate <NUM> and at least a second translation shaft <NUM> extending from the mobile base plate <NUM> in a direction parallel to the translation axis T.

The collapsible step assembly <NUM> further comprises at least a load bearing element <NUM> arranged between the fixed base plate <NUM> and the mobile base plate <NUM> in a direction parallel to the translation axis T, the load bearing element <NUM> being mechanically linked to the mobile step member <NUM>.

The load bearing element <NUM> comprises:.

This arrangement provides a simple and sturdy structure. The upper surface of the fixed step member <NUM>, of the load bearing element <NUM>, and of the mobile step member <NUM> forms a support surface for the foot of a user. The translation of the elements between them allows a deployment of the collapsible step assembly <NUM>. The load bearing element transmits the load applied directly on itself, and the load applied on the mobile step member <NUM>, to the fixed step member <NUM>. As the parts can slide one relatively to the others, the step assembly can be deployed and retracted.

The first translation shaft <NUM> fits with radial play in the first reception hole <NUM>. The second translation shaft <NUM> fits with radial play in the second reception hole <NUM>. Friction between a load bearing element and the first and second translation shaft can be kept to a low value so that the effort required to deploy the collapsible step member <NUM> is kept to a low value.

The load bearing element <NUM> has a shape similar to a rod, and the reception holes <NUM> and <NUM> are transverse through holes. The first translation shaft <NUM> and the second translation shaft <NUM> are fitted into their respective reception hole <NUM>, <NUM>. The load bearing element <NUM> slides over the first translation shaft <NUM> and the second translation shaft <NUM> slides in the load bearing element <NUM> when the mobile step member <NUM> is moved relatively to the fixed step member <NUM>.

The fixed step member <NUM> is metallic. The fixed step member <NUM> is for example made of steel, aluminum, or magnesium. The fixed step member <NUM> can also be made out of injected plastic. The mobile step member <NUM> is metallic. The mobile step member <NUM> is for example made of steel. The mobile step member <NUM> can also be made out of injected plastic.

The fixed base plate <NUM> is rigidly connected to the first translation shaft <NUM>. The first translation shaft is for example welded to the fixed base plate <NUM>. Similarly, the mobile base plate <NUM> is rigidly connected to the second translation shaft <NUM>. The second translation shaft <NUM> is for example welded to the mobile base plate <NUM>.

The first translation shaft <NUM> and the second translation shaft <NUM> are offset one from the other. In an embodiment, the first translation shaft may be identically sized as the second translation shaft. What is meant by identical is that the first translation shaft has same shape and same diameter as the second translation shaft.

According to the embodiment illustrated on <FIG>, the fixed step member <NUM> comprises two first translation shafts <NUM> extending in a direction parallel to the translation axis T and the mobile step member <NUM> comprises two second translation shafts <NUM> extending in a direction parallel to the translation axis T, one first translation shaft <NUM> and one second translation shaft <NUM> being arranged alternately along a direction N of extension of the fixed base plate <NUM>. Having two pairs of translation shafts provides a natural stability and spreads the efforts in the structure, minimizing maximum efforts.

The two first translation shafts <NUM> and the two second translation shafts <NUM> may be coplanar, as it is the case on <FIG>. Alternatively and according to a non-represented embodiment, the two first translation shafts <NUM> and the two second translation shafts <NUM> can be in different parallel planes.

In the embodiment of <FIG>, the two first translation shafts <NUM> are identically sized. The two second translation shafts <NUM> are also identically sized. In this example, a diameter of the first translation shaft <NUM> is comprised between <NUM> millimeters and <NUM> millimeters. Similarly, a diameter of the second translation shaft <NUM> is comprised between <NUM> millimeters and <NUM> millimeters.

The distance d between the direction of extension of the two first translation shafts <NUM> may be comprised between <NUM> centimeters and <NUM> centimeters. The direction N of extension of the fixed base plate <NUM> is perpendicular to the translation axis T.

On the example of <FIG>, the mobile step member <NUM> comprises three second translation shafts <NUM> extending in a direction parallel to the translation axis T. The fixed step member <NUM> comprises two first translation shafts <NUM>, each of the first translation shaft <NUM> being located between two consecutives second translation shafts <NUM> along the direction N of extension of the fixed base plate.

On the example of <FIG>, the collapsible step assembly <NUM> comprises a plurality of load bearing elements <NUM>, each load bearing element <NUM> comprising :.

The load bearing elements <NUM> are disposed next to the other along the translation axis T,
each load bearing element <NUM> is mechanically linked to the mobile step member <NUM>, and each load bearing element <NUM> is configured to transmit to the fixed step member <NUM> a mechanical load applied to the mobile step member <NUM> along a direction perpendicular to the translation axis T.

The plurality of load bearing elements comprises here four load bearing elements referenced respectively <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>. A different number of load bearing elements would also be possible. When the collapsible step assembly <NUM> is in the stowed position S, all the load bearing elements <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM> are engaged on both the first translation shaft <NUM> and the second translation shaft <NUM>. More precisely, the first translation shaft <NUM> fits into the first reception hole <NUM> and the second translation shaft <NUM> fits into the second reception hole <NUM>.

As the collapsible step assembly <NUM> is slided towards the deployed position E, the load bearing element <NUM>-<NUM>, which is closer to the fixed base plate <NUM>, disengages from the second transmission shaft <NUM>. The second reception hole <NUM> is empty. Similarly, the load bearing element <NUM>-<NUM> which is closer to the mobile base plate <NUM> also disengages from the first transmission shafts <NUM>. The first reception hole <NUM> is empty.

When the collapsible step assembly <NUM> is in the fully deployed position E, the load bearing element <NUM>-<NUM> which is closer to the fixed base plate <NUM> is disengaged from the second transmission shafts <NUM> and engaged around the first translation shafts <NUM>. The load bearing element <NUM>-<NUM> which is closer to the mobile base plate <NUM> is disengaged from the first transmission shafts <NUM> and engaged around the second transmission shafts <NUM>. The two intermediate bearing elements <NUM>-<NUM>, <NUM>-<NUM> are engaged on both the first translation shafts <NUM> and the second transmission shafts <NUM>. Having an engagement of at least two consecutive load bearing elements around a translation shaft avoid the mobile step member <NUM> tilting relatively to the fixed step member <NUM> and provides a good stability of the device under high vertical loads.

When the collapsible step member <NUM> is in the stowed position S, an axial end of the first translation shaft <NUM> may be in abutment against the mobile base plate <NUM>. Alternatively, an axial end of the second translation shaft <NUM> may be in abutment against the fixed base plate <NUM>.

The loading bearing elements <NUM> may be identical. Production can be standardized.

In the illustrated embodiment, a length measured in the direction of the translation axis T of the first reception hole <NUM> is comprised between <NUM> millimeters and <NUM> millimeters. Similarly, a length measured in the direction of the translation axis T of the second reception hole <NUM> is comprised between <NUM> millimeters and <NUM> millimeters. These values provide adequate resistance and adequate contact pressure between parts.

On <FIG> the mechanism linking together the various elements to obtain the deployment of the collapsible step member <NUM> has not been represented, in order to simplify <FIG>.

In an embodiment, represented on <FIG> and <FIG>, the collapsible step assembly <NUM> comprises a scissor mechanism <NUM> linking together the fixed step member <NUM>, the load bearing elements <NUM> and the mobile step member <NUM>.

The scissor mechanism comprises a set of pair of linkages <NUM> pivotally fixed together and forming a crisscross pattern. Each pair of linkages links one element with the next element along a translation direction T. On the illustrated example, the collapsible step assembly <NUM> comprises <NUM> load bearing elements <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>. The fixed step member <NUM> is linked with a first load bearing element <NUM>-<NUM> by a pair of linkages. The mobile step member <NUM> is linked with the fourth load bearing element <NUM>-<NUM> by another pair of linkages. The first load bearing element <NUM>-<NUM> is linked with the second load bearing element <NUM>-<NUM>, which is itself linked with the third load bearing element <NUM>-<NUM>. The third load bearing element <NUM>-<NUM> is linked with the fourth load bearing element <NUM>-<NUM>.

In each pair of linkages, each linkage is articulated relatively to the other linkage of the same pair. The articulation axis is located in the middle of each linkage. A1 is the articulation axis of the first pair of linkages <NUM>-<NUM>. A2 is the articulation axis of the second pair <NUM>-<NUM>, and A3 is the articulation axis of the third pair <NUM>-<NUM>.

As illustrated on <FIG>, a lever <NUM> is articulated around a pivot axis <NUM>. The actuation lever <NUM> is linked to a connecting rod <NUM>, itself linked to the first pair of linkages of the scissor mechanism <NUM>. The lever <NUM> is rotated when the actuation cable <NUM> is pulled, which in turn pushes the connecting rod <NUM> and deploys the scissor mechanism <NUM>. The load bearing elements are thus spread from one another and the collapsible step member <NUM> is deployed.

The amplitude of the movement between two consecutive elements add-up to generate a total stroke of the mobile base plate <NUM> relatively to the fixed base plate <NUM>. As the collapsible step member <NUM> is deployed, the gap between two consecutive elements, measured along the translation axis T, increases. In part A of <FIG>, sign d1 shows the gap between two consecutive load bearing members. In part B, the gap is d2, which is larger than d1, corresponding to a more deployed position.

In the embodiment represented on <FIG>, a first scissor mechanism <NUM>-<NUM> is disposed at a first axial end of the fixed step member <NUM>, of the load bearing elements <NUM> and of the mobile step member <NUM>. In this embodiment, a second scissor mechanism <NUM>-<NUM> is disposed at a second axial end of the fixed step member <NUM>, of the load bearing elements <NUM> and of the mobile step member <NUM>. Having one scissor mechanism <NUM>-<NUM>, <NUM>-<NUM> at each axial end of the elements provides a better guiding of the mobile elements.

In an embodiment illustrated on <FIG>, an articulation axis of a pair of linkages is located on a load bearing member. More precisely, the articulation axis A1, A2, A3 of each pair of linkages <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM> is located on the corresponding load bearing member <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>. An articulation axis between a linkage from one pair of linkages and a linkage from the consecutive pair of linkages is located halfway between the corresponding load bearings elements. For example, the articulation axis B12a, B12b between a linkage from the pair of linkages <NUM>-<NUM> and a linkage from the consecutive pair of linkages <NUM>-<NUM> is located halfway between the load bearings element <NUM>-<NUM> and the load bearings element <NUM>-<NUM>.

In an embodiment illustrated on <FIG>, an articulation axis between a linkage from one pair of linkages and a linkage from the consecutive pair of linkages is located within a load bearing member. For example, the articulation axis B12a, B12b between a linkage from the pair of linkages <NUM>-<NUM> and a linkage from the consecutive pair of linkages <NUM>-<NUM> is located within the load bearing element <NUM>-<NUM>.

The articulation axis B12a, B12b are housed in a cavity of the load bearing member <NUM>-<NUM>. The articulation axis are distant from the walls defining the cavity to allow the articulation axis to move inside the cavity during the deployment stroke. This arrangement is repeated the same way for the other load bearing elements.

The operation of a collapsible member <NUM> has been described. Several such collapsible members may be implemented on the same vehicle.

According to an embodiment of the truck <NUM>, illustrated on <FIG>, the collapsible step assembly <NUM> comprises a first collapsible member 4a. The collapsible step assembly <NUM> also comprises a second collapsible member 4b configured to be moved from the stowed position S to the deployed position E synchronously with the collapsible step assembly 1a. The two collapsible step members 4a, 4b are fitted at different heights, on the same lateral side of the truck <NUM>, and are deployed together when the entry door <NUM> is opened. This arrangement reduces the gap between two consecutive supports available to the users. The truck side surface in the area <NUM> close to the first collapsible member 4a and second collapsible member 4b can be smooth allowing a clean airflow along the surface of the truck <NUM>.

According to another embodiment, illustrated on <FIG>, the truck <NUM> comprises a first collapsible step assembly <NUM> as described earlier and a second collapsible step assembly 1b as described earlier. The first collapsible step assembly <NUM> comprises a first collapsible step member <NUM> configured to be moved from the stowed position S to the deployed position E by the actuation cable <NUM> in response to an opening of a first entry door <NUM>,
and the second collapsible step assembly 1b comprises a second step member 4b configured to be moved from the stowed position S to the deployed position E by the actuation cable <NUM> in response to an opening of a second entry door 40b.

Similar collapsible step assemblies 1a, 1b can be fitted on either side of the truck <NUM>. One device 1a is deployed when the driver door <NUM> is opened and the other device 1b is deployed when the passenger door 40b is opened. The operation of the device 1b equipping the passenger's door 40b is similar to the operation of the device 1a equipping the driver's door.

Considering the orientation of the collapsible step member <NUM> relatively to the truck structure, the translation axis T can make an angle comprises between <NUM>° and <NUM>° with a transversal axis Y of the truck. This is for example the case for the collapsible step member <NUM> controlled by the operation of the driver's door of the truck of <FIG>.

Alternatively, the translation axis T can make an angle h larger than <NUM>° with a transversal axis Y of the truck. This is the case for the collapsible step member 4b controlled by the operation of the passenger's door on <FIG>. The access to the cabin <NUM> can be made easier because more room is made available between the step and the rotation axis of the entry door 40b.

Claim 1:
A collapsible step assembly (<NUM>) for helping a user entering a cabin (<NUM>) of an industrial vehicle (<NUM>),
the collapsible step assembly (<NUM>) comprising:
- a collapsible step member (<NUM>) configured to be movable between :
-- a stowed position (S) in which the collapsible step member (<NUM>) is set-back from or flush with an external surface of the industrial vehicle (<NUM>), and
-- a deployed position (E) in which the collapsible step member (<NUM>) projects out of the external surface of the industrial vehicle (<NUM>),
- an actuation member (<NUM>) configured to link the collapsible step member (<NUM>) and an entry door of the cabin (<NUM>),
in which the collapsible step member (<NUM>) is configured to be moved along a translation axis (T) from the stowed position (S) to the deployed position (E) by the actuation member (<NUM>) in response to an opening of the entry door (<NUM>),
in which the collapsible step member (<NUM>) comprises:
- a fixed step member (<NUM>) comprising a fixed base plate (<NUM>) and at least a first translation shaft (<NUM>) extending from the fixed base plate (<NUM>) in a direction parallel to the translation axis (T),
- a mobile step member (<NUM>) comprising a mobile base plate (<NUM>) and at least a second translation shaft (<NUM>) extending from the mobile base plate (<NUM>) in a direction parallel to the translation axis (T), the collapsible step assembly (<NUM>) further comprising at least a load bearing element (<NUM>) arranged between the fixed base plate (<NUM>) and the mobile base plate (<NUM>) in a direction parallel to the translation axis (T), the load bearing element (<NUM>) being mechanically linked to the mobile step member (<NUM>),
in which the load bearing element (<NUM>) comprises :
a first reception hole (<NUM>) configured to receive the first translation shaft (<NUM>),
a second reception hole (<NUM>) configured to receive the second translation shaft (<NUM>),
and in which the load bearing element (<NUM>) is configured to transmit to the fixed step member (<NUM>) via the first translation shaft (<NUM>) a mechanical load applied to the mobile step member (<NUM>) alonga direction perpendicular to the translation axis (T).