Abstract:
A retractable step assembly  10, 51, 60  for a vehicle. The assembly  10, 51, 60  comprises a step member  24 , and a connection arrangement of variable length extendible from the step member  24  to a mounting  50  on the vehicle. The assembly  10  is configured such that operation thereof causes the connection arrangement to selectively increase or decrease in length. At a minimum length of the connection arrangement the step  24  is retracted, and at a maximum length of the connection arrangement the step  24  is in an in use position.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims benefit of United Kingdom Application No. GB 0905816.5 filed Apr. 3, 2009, the entire disclosure of which is hereby incorporated herein by reference for all purposes. 
       BACKGROUND OF THE INVENTION 
       [0002]    This invention relates to retractable step assemblies for vehicles. 
         [0003]    With taller vehicles such as for instance SUVs, it is often desirable to provide a step to aid a person getting in and out of the vehicle. It is often required that such steps retract beneath the vehicle prior to driving thereof, and particularly that they do not extend laterally outwards beyond the remainder of the vehicle during motion. 
       SUMMARY OF THE INVENTION 
       [0004]    According to the present invention there is provided a retractable step assembly for a vehicle, the assembly comprising a step member, a connection arrangement of variable length extendible from the step member to a mounting on the vehicle, the assembly being configured such that operation thereof causes the connection arrangement to selectively increase or decrease in length, and at a minimum length of the connection arrangement the step is retracted, and at a maximum length of the connection arrangement the step is in an in use position. 
         [0005]    The step member may be hollow, and a substantial part of the connection arrangement may locate within the step member at least at a minimum length thereof. 
         [0006]    The connection arrangement may include first and second elongate members in a telescopic configuration with a one of the first or second elongate members extendible into the other, such that at a minimum length of the connection arrangement a substantial part of the first or second elongate member locates within the other, and at a maximum length a substantial part of the one elongate member extends from the other elongate member. 
         [0007]    The assembly may be configured such that as the step member moves to an in use position it also moves downwardly. 
         [0008]    The step member may be connectable to a vehicle by a first pivoted linkage. The assembly may be configured such that when the step member is in an in use position, the first pivoted linkage extends downwardly, and may extend substantially vertically downwards. 
         [0009]    The mounting of the connection arrangement to a vehicle may be in the form of a second pivoted linkage. The second pivoted linkage may be shorter than the first pivoted linkage, may be significantly shorter, and may be between two and eight times shorter. 
         [0010]    A plurality of spaced connection arrangements may be provided along the length of the step member. 
         [0011]    In one form of the invention the first elongate member is rotatable and is threadably engageable with the second elongate member such that rotation of the first elongate member in one direction causes the first and second elongate members to move together towards the minimum length, and rotation in the other direction causes moving apart towards the maximum length. 
         [0012]    The assembly may include a motor to rotate the first elongate member and thus vary the length of the connection arrangement. The motor may be located in the step. 
         [0013]    In one embodiment a motor is provided for each connection arrangement. 
         [0014]    In a second embodiment a drive is provided between the motor and each connection arrangement. 
         [0015]    In a further form of the invention the first and second elongate members have a piston and cylinder configuration, with one elongate member constituting the piston which slidably locates in the other elongate member as the cylinder. 
         [0016]    A hydraulic or pneumatic pump may be connected to the cylinder to move the piston. A pump may be provided for each connection arrangement, or a single pump may power a plurality of connection arrangements, and may power connection arrangements on a plurality of step assemblies on a vehicle. 
         [0017]    The pump or pumps may be located in the step, or alternatively elsewhere on a vehicle. 
         [0018]    The pump or pumps may be in the form of a combined pump and reservoir unit. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    For a better understanding of the invention, and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: 
           [0020]      FIG. 1  is a diagrammatic cross sectional view of a first step assembly according to the invention in a retracted condition; 
           [0021]      FIG. 2  is a similar view to  FIG. 1  but in an in use condition; 
           [0022]      FIG. 3  is a diagrammatic perspective view of a second step assembly in an in use condition; 
           [0023]      FIG. 4  is a diagrammatic perspective side view of the assembly of  FIG. 3  in a retracted condition; 
           [0024]      FIGS. 5 and 6  are respectively diagrammatic cross sectional side views of the assembly of  FIG. 3  in respectively a retracted and in use condition; and 
           [0025]      FIGS. 7 and 8  are similar views respectively to  FIGS. 1 and 2  but of a third step assembly according to the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0026]      FIGS. 1 and 2  show a first retractable step assembly  10  mounted on a vehicle  12 , only part of which is shown, such as an SUV. The vehicle  12  is shown with a door  14  with a lower cladding  16 . The sill is shown with a cover moulding  18 . The interior floor of the vehicle is shown at  20 , and the ground is indicated at  22 . 
         [0027]    The assembly  10  includes a hollow step member  24  with a plate  26  on a top surface thereof. The step member  24  is connected to the vehicle  12  at three spaced locations, including two outer locations and a central location, with one of the outer locations shown in the drawings. 
         [0028]    The two outer locations include a motor  28  located within the hollow step member  24  and connected to a gearbox  30 . A threaded bar  32  extends from the gearbox  30  and points inwardly towards the vehicle  12 . A tubular member  34  locates around the threaded bar  32 , and is threadably connected thereto by a trapped nut  36  at the outer end of the tubular member  34 . The nut  36  locates in a cylindrical recess  38  in the outer end of the tubular member  34 , and a damper spring  40  extends between the inner end of the recess  38  and the nut  36 . 
         [0029]    The tubular member  34  slidably extends through an inner part  42  of the step. The inner end  44  of the tubular member mounts an inner pivotal linkage  46  to the vehicle  12 . A longer outer pivotal linkage  48  extends downwardly from the vehicle to a mounting  50 , located on top of an outer end of the inner part  42  of the step member  24 , and mounted to the step member  24 . 
         [0030]    In use in a retracted condition as shown in  FIG. 1 , the threaded bar  32  is located substantially wholly within the tubular member  34 . The assembly  10  locates immediately beneath the vehicle  12  with the outer side of the step member  24  not extending beyond an outermost part of the door  14 . When the step assembly  10  is to be deployed, which may be automatically actuated upon the door  14  being opened or pressing of a key fob, each motor  28  is actuated causing rotation of the threaded bar  32  which causes the tubular member  34  to move inwardly relative to the vehicle  12 . 
         [0031]    By virtue of the engagement of the inner end  44  of the tubular member  34  with the inner pivotal linkage  46 , the step member  24  is urged outwardly. As a result of the longer outer pivotal linkage  48  the step member  24  is also urged downwardly to the position shown in  FIG. 2  with the outer pivotal linkage  48  extending substantially vertically downwardly, and the plate  26  extending substantially horizontally. 
         [0032]    In the position shown in  FIG. 2  the plate  26  is at a correct horizontal orientation for a person getting into or out of the vehicle  12 . Also as shown, the top of the plate  26  is at substantially half the distance between the ground  22  and the vehicle interior floor  20 . As the outer pivotal linkage  48  extends substantially, vertically, downward forces on the plate  26  are urged directly downwardly through the outer pivotal linkage  48 . The step member  24  is retracted by the motor  28  driving the threaded bar  32  in the opposite direction, which may be automatically actuated upon the door  14  being closed. 
         [0033]      FIGS. 3 to 6  shows a second assembly  51  which operates in a similar manner to the assembly  10 , and only the differences therein will be described. Similar reference numerals are used for similar components. In this instance, a single motor  28  is provided adjacent the central connection  52 . The motor  28  connects to the threaded bars  32  via a driven shaft  54  extending through the length of the step member  24  and engaging with gearboxes  56  at the connections at each end of the step member  24 . 
         [0034]    There are thus described retractable step assemblies for vehicles where the motor or motors and part or all of other components are located wholly within a hollow step member. This therefore provides significant protection for these components from the elements. This also provides a very neat and compact arrangement. By varying the linkages and potentially the angle of the plate on the step member, the same or similar components and arrangements could be used in a wide range of vehicles. 
         [0035]      FIGS. 7 and 8  show a third retractable step assembly  60  which is similar in most respects to the assembly  10  except that the assembly  60  is controlled by a pump  62 . In this instance the pivotal linkage  46  pivotally mounts one end  64  of a piston member  66 . The other end  68  of the piston member  66  locates in a cylinder  70 . The mounting  50  is provided on one side of the cylinder  70 . 
         [0036]    In use, the pump  62  pumps or sucks hydraulic or pneumatic fluid into the cylinder  70  to move the piston  66  and hence increase or decrease the combined length of the piston  66  and cylinder  70 . The assembly  60  will therefore operate in a similar manner to the assembly  10 . 
         [0037]    In the drawings the pump  62  is shown within the step  24 . The pump could though be located elsewhere on the vehicle as shown at  72  in the drawings. A single pump  62  could power one piston and cylinder configuration, or could power all of the piston cylinder configurations in a step, and perhaps power piston and cylinder configurations in more than step on a vehicle. 
         [0038]    Various other modifications may be made without departing from the scope of the invention. For instance a different arrangement of linkages may be used. A different number of connections between the step member and the vehicle may be included. A different connection may be provided between the motor and the threaded member. A different arrangement could be provided to produce a variable length member. 
         [0039]    Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon. 
         [0040]    It will be appreciated that the invention is not restricted to the particular embodiment that has been described, and that variations may be made therein without departing from the scope of the invention as defined in the appended claims, as interpreted in accordance with principles of prevailing law, including the doctrine of equivalents or any other principle that enlarges the enforceable scope of a claim beyond its literal scope. Unless the context indicates otherwise, a reference in a claim to the number of instances of an element, be it a reference to one instance or more than one instance, requires at least the stated number of instances of the element but is not intended to exclude from the scope of the claim a structure or method having more instances of that element than stated. The word “comprise” or a derivative thereof, when used in a claim, is used in a nonexclusive sense that is not intended to exclude the presence of other elements or steps in a claimed structure or method.