Abstract:
A foldable ladder for providing access to an opening including: a first motorized drive mechanism for moving a cover for the opening between a closed position and an open position; a second motorized drive mechanism coupled to a plurality of foldable ladder portions for moving the ladder portions between a folded configuration and an unfolded configuration; such that, in moving the cover between the closed and an open position, the first motorized drive mechanism triggers the second motorized drive mechanism to move the ladder portions between the folded configuration and unfolded configuration.

Description:
REFERENCE TO RELATED APPLICATION 
     This application claims priority from European Patent Application No. 13191834 filed on Nov. 6, 2013, the entirety of which is incorporated herein by reference. 
     TECHNICAL FIELD AND BACKGROUND 
     The present disclosure relates to a foldable ladder device. In particular, this disclosure relates to a foldable ladder device which may be folded or unfolded without requiring manual effort. 
     In a house or commercial premises, there is frequently an upper room or area to which access is not required on a frequent basis. Because of this, it is unnecessary to have a permanent means, such as a staircase, of accessing the upper area in question. It is desirable that the area be ordinarily sealed off and with access provided by a means which is temporarily fixed in place. 
     Many such solutions exist to solve the aforementioned problem. However, these solutions suffer from a number of disadvantages. Solutions such as those described in US2009/0166129 and GB311390 are bulky and occupy large amounts of space in the upper area when not in use. EP 1 035 268 provides a foldable solution, wherein a ladder arrangement may be folded when not in use and unfolded to allow access to the upper area. However, EP 1 035 268 relies on a complex arrangement of bars and folding elements to achieve its folding function. Further solutions known in the art provide for a foldable action, however a manual interaction with the device is required to move the device from folded to an unfolded configuration. 
     A solution which overcomes the above problems would be an improvement on the state of the art. 
     SUMMARY OF THE INVENTION 
     Disclosed is a foldable ladder for providing access to an opening that includes: a first motorized drive mechanism for moving a cover for the opening between a closed position and an open position; a second motorized drive mechanism coupled to a plurality of foldable ladder portions for moving the ladder portions between a folded configuration and unfolded configuration; such that, in moving the cover between the closed and the open position, the first motorized drive mechanism triggers the second motorized drive mechanism to move the ladder portions between the folded configuration and the unfolded configuration. 
     This provides the advantage of a fully automated device which can move from a folded configuration, in which an opening is sealed, to an unfolded configuration in which access to the opening is provided. The dual drive mechanism arrangement provides for a smooth transition between folded and unfolded states and overcomes the need for excessive bracketing and cabling to transition between the states. Furthermore, the invention provides that no manual interaction with the ladder is required on the part of a user to transition between the states, unlike other solutions in which the cover must be manually opened or the ladder manually extracted. 
     In moving the ladder portions between the unfolded and the folded configuration, the second motorized drive mechanism may trigger the first motorized drive mechanism to move the cover between an open position and a closed position. This provides for a smooth transition between unfolded and folded states and further provides that no manual interaction with the ladder is required on the part of a user to transition between the states. 
     The first and second drive mechanisms may include electrical actuators. This provides for reliable automation of the first and second drive mechanisms. 
     The second drive mechanism may be positioned to the cover. This allows the second drive mechanism to unfold the ladder once triggered by the motion of the first drive mechanism and resultant opening of the cover. This further provides for a compact design which occupies space on the opening cover rather than occupying space within the upper area to which access is provided by the ladder. 
     The second drive mechanism may drive a gear arrangement. The gear arrangement may include a rack and pinion arrangement. This allows for a very smooth motion between folded and unfolded states to be achieved. It allows for control and adjustment of the motion of the ladder, if required, to suit the particular location in which the ladder is to be fitted and the space into which it is to extend. 
     The plurality of foldable ladder portions may include a first portion fixed to the cover; a second portion hingedly connected to the first portion; a third portion hingedly connected to the second portion. Hinging the second portion to the first portion allows the motorized motion of the first portion to control the second portion. Likewise, hinging the third portion to the second portion allows the motion of the second portion to control the third portion. 
     In the folded configuration, the first, second and third portions may rest atop each other. This further provides for a compact design which minimizes the space occupied by the folded ladder in the upper area to which access is provided by the ladder. 
     In the unfolded configuration, the first, second and third portions may abut each other. This has the advantage of providing a continuous set of rungs to allow for ease of access to the opening. 
     The third portion may further include an extendible end piece. This allows the third portion to be adjusted to fit a range of floor to ceiling heights when the ladder is in an unfolded configuration. 
     The extendible end piece may include a wheel. The wheel provides the advantage of preventing scraping or dragging on a floor surface when the ladder is moved between configurations. 
     The first and second drive mechanisms may be activatable by remote control. This allows the ladder to be fully automated and requiring no manual intervention by a user, save for pushing of a button on a remote control device to move the ladder between a folded and unfolded configuration and vice versa. 
     The first and second drive mechanisms may include a secondary power source in case of failure of a primary power source. As such, in case of power failure, the ladder may still be operated. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the present disclosure will be described, by way of example only, with reference to the accompanying drawings, in which: 
         FIG. 1  shows the ladder according to one embodiment in the closed or folded configuration; 
         FIG. 2  shows the ladder in a partially unfolded configuration; 
         FIG. 3  shows the ladder in an open or unfolded configuration; 
         FIG. 4  shows an exploded view of the rack and pinion mechanism of the device; and 
         FIG. 5  shows a further embodiment of the rack and pinion mechanism of the device. 
     
    
    
     DETAILED DESCRIPTION 
     The invention will now be described more fully with reference to the accompanying figures in which exemplary embodiments of the invention are shown. However, the invention may be embodied in many different forms and should not be construed as limited to the representative embodiments described below. The exemplary embodiments are provided so that this disclosure will be both thorough and complete and will fully convey the scope of the invention and enable one of ordinary skill in the art to make, use, and practice the invention. 
       FIG. 1  shows the ladder  1  in a folded configuration. The ladder includes a first portion  2 , a second portion  3  and a third portion  4  which rest atop each other. The first portion is further fixed to a cover  5  such as a door. The cover  5  serves to seal the opening to which the ladder  1  provides access, when the ladder is in the folded configuration. Further components of the ladder can be seen in  FIG. 2  in which the ladder is in a partially unfolded configuration. A first drive mechanism  6  is coupled to the first portion  2  of the ladder by a pair of arm elements  7 ,  7 ′. The arm elements may be foldable along their length into upper pieces  8 ,  8 ′ which are pivotably connected to the drive mechanism  6  and lower pieces  9 ,  9 ′ which are pivotably connected to the cover  5 . The lower pieces may also be pivotably connected to the first portion  2  of the ladder  1 . The first drive mechanism comprises a pair ( 20 , 21 ) of electrical actuators. 
     A second drive mechanism  10  is attached to the cover  5  and to the first portion  2  of the ladder  1 . The second drive mechanism comprises a pair ( 27 , 28 ) of electrical actuators ( FIG. 3 ). The second drive mechanism drives a gear arrangement  11  which controls the separation of the second portion  3  of the ladder from atop the first portion  2  of the ladder when the ladder is moved from the folded to the unfolded configuration. Likewise, the second drive mechanism drives the gear arrangement  11  to control the movement of the second portion  3  of the ladder to atop the first portion  2  of the ladder when the ladder is moved from the unfolded to the folded configuration. The gear arrangement is a rack  22  and pinion  23  type arrangement. The second portion  3  is coupled to the first portion by means of a hinge  12 . 
     The third portion  4  is coupled to the second portion by means of a hinge  12 ′. The third portion  4  is further coupled to the first portion  2  by means of a cable  13 . A guidepiece  14  for the cable  13  is provided on the second portion  3  so that when moving between the folded and unfolded configurations, the movement of the cable  13  may be controlled. 
     The third portion further comprises an end piece  30 . The end piece comprises a wheel  15  which prevents scraping or dragging on a floor surface when the ladder is moved between configurations. The end piece may be extendible such that the third portion  4  can be adjusted to fit a range of floor to ceiling heights when in an unfolded configuration. 
       FIG. 3  shows the ladder  1  in a fully unfolded configuration. The lower end  16  of first portion  2  abuts the upper end  16 ′ of the second portion  3 , the lower end  17  of the second portion abuts the upper end  17 ′ of the third portion  4 . In this manner, a continuous set of rungs  18  is provided to allow a user access the opening  19 . 
       FIG. 4  shows an exploded view of the rack  22  and pinion  23  mechanism of the device. A pinion piece  23  is fixed to a pinion bracket  31  which is positioned on the lower end of each side of the first portion  2 . The pinion  23  consists of a circular piece  32  with a toothed circumference  33 . The pinion  23  rotates around a central axis point  34 . The pinion bracket  31  is integrated into the hinge  12  which couples the second portion  3  to the first portion  2 . A rack is positioned on each side of the lower end of the first portion  2  and is held to the first portion by means of a bracket  29 . Each rack  22  consists of a toothed track  35  with a series of teeth  36  dimensioned to engage with the toothed circumference  33  of the pinion. Each rack  22  is fixed to an arm  37  of the each of the actuators ( 27 , 28 ). The arm  37  is moveable in an out of a sleeve piece  38 , such that when the actuator extends, the arm  37  extends from the sleeve piece and when the actuator retracts, the arm  37  is drawn into the sleeve piece  38 . The rack  22  and pinion  23  are positioned such that when the arm  37  of the actuator extends or retracts, the pinion  23  rotates over the toothed track of the rack  22 . The rack and pinion may be made from plastic or a similar durable material. The bracket  29  may be made from plastic or aluminium while the ladder portions may be made from wood, plastic or aluminium. The bracket  29  and hinge  12  may be fixed to the ladder portions by fastening means  41 , for example by nails or by screws. 
     The ladder  1  will now be described in use. With the ladder  1  in its folded configuration, the cover  5  is closed. The pair of actuators  20 ,  21  of the first drive mechanism are in a fully extended position. The actuators  20 ,  21  may be activated by means of a remote control. When activated, the actuators retract to allow the arm elements  7 ,  7 ′ to drop the cover  5  to an open position. The actuators may pull a cable, drive a lever or drive a gear arrangement in order to drop the cover  5  to an open position. The upper pieces  8 ,  8 ′ of the arms are attached to a fixed frame  24  surrounding the opening  19  and are operated by the actuators. There is a joint  25  in the upper pieces  8 , 8 ′ coupled to a bracket  26  on the fixed frame  24 . Adjustment of the position of the bracket  26  on the frame  24  ensures that the actuators ( 20 , 21 ) can fully close the cover  5  when the ladder  1  is in the folded configuration. The lower pieces  9 ,  9 ′ of the arm elements  7 ,  7 ′ are attached to the cover  5 . The upper and lower pieces are joined by a nut and bolt to create an elbow type joint. 
     When the arm elements are almost fully extended and the cover  5  is in a partially open configuration, the actuators  27 ,  28  of the second drive mechanism are activated by a switch mounted on the actuators  20 ,  21  of the first drive mechanism. The second drive mechanism is triggered when the actuators  20 ,  21  of the first drive mechanism have almost fully retracted. The actuators  27 ,  28  of the second drive mechanism are in a fully extended position when the ladder  1  is in the folded configuration and the cover  5  is closed. When the second drive mechanism is activated, the actuators  27 ,  28  retract. The actuator arm  37  is thus drawn into the sleeve piece  38  which has the effect of pulling the rack  22  beneath the pinion  23 . The pinion  23  rotates upon the rack surface and as it does so, the second ladder portion  3  is unfolded from the first portion  2 . The actuators  27 ,  28  are each joined to a rack  22  which slides within a channel  39  on the base of the bracket  29 . The pinion  23  is mounted on the side of the hinge  12 . As the rack  22  is engaged with the pinion  23  it unfolds the second portion  3  of the ladder  1 . As the second portion  3  unfolds, the third portion  4  begins to unfold under the force of gravity and its movement is controlled by the cable  13 . The cable  13  is attached from the hinge  12 ′ at the upper end of the third portion through the guidepiece  14  on the second portion  3  to the bracket  29  on the first portion  2 . The cable  13  it is attached to a spring or elastic means on the first portion  2 . This arrangement keeps the cable  13  taut when the ladder  1  is in the folded configuration. 
     When the actuators  27 ,  28  are fully retracted, the ladder  1  is in the unfolded configuration and access to the opening  19  is provided. The end piece  30  of the third portion may be extended such that the third portion  4  can be adjusted to fit a range of floor to ceiling heights when in an unfolded configuration. An adjustment of plus or minus 100 mm (4 inches) may be provided on a given ceiling height. 
     In an alternative embodiment of the invention ( FIG. 5 ), placement of another pinion gear  40  between the rack  22  and the existing pinion gear  23  allows the opposite motion to that described above to be achieved. As such, when the actuators  27 ,  28  are in a retracted position, the ladder is in the folded configuration. This allows for a shorter ladder frame and a smaller overall unit size. 
     Closing the stairs is again triggered by the remote control. The actuators  27 ,  28  start to extend and thus the arm  37  extends from the sleeve piece  38 , which has the effect of pushing the rack  22  beneath the pinion  23 . The pinion  23  rotates upon the rack surface and as it does so, the second ladder portion  3  is folded up towards the first portion  2 . Thus, the ladder  1  begins to move to the folded configuration. The cable  13  further controls the closing of the third portion  4 . The third portion  4  is drawn towards its folded position atop the second portion  3 . As the ladder moves towards its folded configuration, the motion of the actuators  27 ,  28  of the second drive mechanism activates a switch which triggers the actuators  20 ,  21  of the first drive mechanism. The actuators  20 ,  21  of the first drive mechanism act on the arm elements  7 ,  7 ′ to close the cover  5  and move the ladder  1  to its folded configuration. 
     The ladder is fully automated, in that with the touch of a button the cover  5  opens and the ladder  1  unfolds to the floor. No manual intervention by a user is required to either open the cover or move and adjust the ladder mechanism. 
     The actuators  20 ,  21 ,  27 ,  28  are mains powered. They further comprise a built in battery backup. As such, in case of power failure, the ladder may still be operated for a limited amount of times. When power is restored, the battery goes into a charging mode. 
     Although the foregoing description provides embodiments of the invention by way of example, it is envisioned that other embodiments may perform similar functions and/or achieve similar results. Any and all such equivalent embodiments and examples are within the scope of the present invention. It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination.