A stair arrangement

Abstract

 A stair arrangement (1) comprising a frame (2) and a door (3) associated with the frame at a hinge end (4), the frame presenting a bias strut (14) with a suspended pivot end (19) secured to a hinge arm (15) which extends to a portion of the door displaced from the hinge end (4), a door arm (16) extending from towards an opposite end (23) of the door to the hinge end (4) to a pivot position upon the hinge arm (15), the pivot position towards the pivot end association of the hinge arm (15) to define a mechanical lever to regulate with the bias strut (14) pivot movement of the door (3) about the hinge end (4).

Description

[0001] The present invention relates to stair arrangements and more particularly to stair arrangements utilised to provide access through a loft aperture to a loft in a building.

[0002] Within a range of buildings including domestic premises it is common for a loft to be provided in a roof space. These lofts provide convenient storage areas as well as potential occasional rooms. However, it is typically inconvenient to provide a permanent access stairway and in such circumstances a stair arrangement is provided which generally folds and can be lifted into the loft space when not required. A convenient form of such stair arrangements comprises folded step segments which fold upon one another and generally within the plan area of a door which is arranged across the loft access aperture. The step segments may simply unfold upon deployment or incorporate bias springs to urge unfolding of the segments under gravity upon deployment. In any event, a number of stair arrangements have been provided with varying degrees of ease of use and operability.

[0003] In accordance with aspects of the present invention there is provided a stair arrangement comprising a frame and a door associated with the frame at a hinge end, the frame presenting a bias strut with a suspended pivot end secured to a hinge arm which extends to a portion of the door displaced from the hinge end, a door arm extending from towards an opposite end of the door to the hinge end to a pivot position upon the hinge arm, the pivot position towards the pivot end association of the hinge arm to define a mechanical lever to regulate with the bias strut pivot movement of the door about the hinge end.

[0004] Generally, the door has a respective bias strut, hinge arm and door arm adjacent each edge of the door between the hinge end and the opposite end.

[0005] Generally, the suspended pivot end is held by a fixing. Possibly, the suspended pivot end is suspended upon a hanger to limit fall as the door moves about the pivot end. Possibly, the hanger is angled relative to an upper edge of the frame to present the pivot end when engaged by the bias strut.

[0006] Possibly, the arrangement includes a gripper to engage the suspended pivot end for retention of position. Typically, the gripper comprises a clip presented upon a bracket. Possibly, the clip is a pipe retainer.

[0007] Generally, an opposite end of the bias strut is fixed towards an upper edge of the frame.

[0008] Generally, the bias strut remains substantially within a width of the frame defined by an upper edge of the frame and a lower edge of the frame.

[0009] Generally, the bias strut is supported at a displaced position from the pivot end. Typically support is provided by a hanger.

[0010] Generally, the door presents a foldable step assembly having a plurality of step segments. Typically the step segments form a ladder or stair. Possibly, the foldable step assembly incorporates a foldable hand rail.

[0011] Generally, a first step segment is substantially fixed along one side of the door within a plan dimension of the door. Typically the first step segment has a segment hinge away from the hinge end of the door and the segment hinge secured to a further step segment. Generally, hinges are provided between abutment ends of the step segments to allow folding of the foldable step assembly whilst when the abutment ends of the step segments are in abutment then the foldable step assembly is straight with alignment between the step segments.

[0012] Typically, a last step segment has a chamfer end. Possibly, the chamfer end is provided by a shoe. Possibly the shoe comprises an over sleeve for an end portion of the last step segment.

[0013] Possibly, the chamfer end defines a step angle when in engagement with a surface. Possibly, the arrangement may be associated with one of a range of chamfer ends defining respectively different step angles. Typically, the step angle determines a limit of pivot movement about the hinge end by the door. Generally, treads in each step segment are orientated to be substantially horizontal when the chamfer end defines the step angle in engagement with a surface. Generally, the bias strut and hinge arm are arranged in a side by side configuration with the door arm. Typically, the bias strut pivots about an association with the frame to lift the pivot end when the door is presented across the frame into a substantially parallel association with the frame. Alternatively, the bias strut is arranged to slide within a channel upon a rail as the door moves about the pivot end to extend across the frame in a substantially parallel relationship with the frame.

[0014] Possibly, the door arm is extendible for variation upon installation of the stair arrangement. Generally, the door arm when extendible is lockable for use subsequent to installation. Possibly, the door arm is of variable length dependent upon the chamfer end.

[0015] Typically, the bias strut comprises a gas spring.

[0016] Typically, the frame and/or the door are formed from wood.

[0017] Generally, the bias strut is secured to an upper edge of the frame through an angle bracket.

[0018] Aspects of the present invention will now be described by way of example and with reference to the accompanying drawings in which:

Figure 1 is a pictorial perspective view of a stair arrangement in accordance with aspects of the present invention;

Figure 2 is a pictorial illustration of the stair arrangement depicted in figure 1 at an intermediate deployment stage;

Figure 3 is a pictorial illustration of the stair arrangement depicted in figures 1 and 2 at a further deployment stage;

Figure 4 is a pictorial plan view of the stair arrangement in a stored or non-deployed condition;

Figure 5 is a pictorial perspective view of the arrangement depicted in figure 4;

Figure 6 is a pictorial side view of the stair arrangement depicted in figures 4 and 5; and,

Figure 7 is a front cross-section of a gripper utilised in an arrangement according to some aspects of the present invention.

[0019] As indicated above stair arrangements are utilised with respect to lofts and other elevated areas to provide access either for storage or occasional bedrooms etc. In such circumstances the stair arrangement must be resilient whilst avoiding expensive, cumbersome and intrusive mechanisms. Figure 1 provides a schematic illustration of a stair arrangement 1 in accordance with aspects of the present invention in a deployed state. The arrangement 1 comprises a frame 2 which will be secured in a loft aperture. At one end 2a a door 3 is secured along a hinge edge 4. The door 3 is associated with a foldable ladder or stair assembly 5 in the form of segments 5a, 5b, 5c associated about abutting ends with hinges 7, 8.

[0020] A first segment 5a generally remains within the plan perimeter of the door 3 whilst the other segments 5b, 5c can be folded to also remain when in a folded state within this area to allow the door with the folded stair or ladder 5 to be pivoted through an aperture created by the frame 2 in a stowed state.

[0021] Other stair or ladder segments 5b, 5c extend down from the door 3 in a deployed state in order to present a chamfered end 9 to a ground surface. The chamfered end 9 is generally designed such that the end is in flat engagement with the ground surface for stability. In such circumstances the chamfered end 9 can be created through shaping of the bottom most ends of the last stair segment 5c or by application of a shoe to define the angle of the chamfered end 9. In such circumstances a chamfered end 9 defines a deployment or step angle 10 which in turn defines a pivot range 11 for the door 3 about the hinge edge 4. The shoes utilised may have different angles in order to define different presentations of step angles 10 and therefore different deployment heights for the arrangement 1. It will be understood that a foldable ladder or stair 5 will incorporate step treads 12 generally angled to be substantially horizontal when the arrangement 1 is deployed.

[0022] In accordance with aspects of the present invention the door 3 is regulated in terms of rotation about the hinge end 4 as well as assistance provided through at least one bias strut 14 but as illustrated typically there will be two bias struts either side of the door 3. The bias struts 14 are associated with a hinge arm 15 and a door arm 16 presented in order to provide through mechanical lever advantage appropriate regulation of movement of the door 3 about the hinge end 4 as well as assistance in use. Normally the bias strut 14 is provided through a gas strut or ram.

[0023] The bias strut 14 is secured at one end 17 to a lateral part 2b of the frame 2 through typically a mounting plate 18. The mounting plate 18 may comprise an angled bracket which extends over an upper edge of the frame 2b. At the other end of the strut 14 a pivot end 19 is suspended upon typically a hanger 20 in association with the hinge arm 15. Similarly, the bias strut 14 is also supported by a further support element 21 to ensure appropriate presentation of the bias strut 14 in use. It will be appreciated that the bias strut 14 remains within the width of the frame 2b.

[0024] The suspended bias end 19 is secured to one end of the hinge arm 15 with the other end secured to the door 3 at a displaced position 22 from the hinge end 14 of the door 3.

[0025] Along the hinge arm 15 towards the pivot end 19 the door arm 16 is secured such that it extends to an opposite end 23 of the door 3 to the hinge end 4. The position of the engagement between the door arm 16 and the hinge arm 15 is chosen in order to create the desired level of mechanical lever advantage for regulating rotation of the door 3 about the hinge end 4 as well as assistance for return of the door 3 to engagement with the frame 2 as a result of bias generated within the strut 4 through extension.

[0026] It will be noted that the mountings at the end 17, the pivot end 19 between the bias strut 14 and the hinge arm 15, the junction between the door arm 16 and the hinge arm 15 as well as the mountings at the portion 22 and end 23 all allow relative pivot movement to facilitate rotation of the door 3 over the pivot range 11.

[0027] As indicated above generally a gas or hydraulic ram is utilised with respect to the bias strut 14 but it will also be appreciated that a mechanical spring or pulley arrangement could also be utilised in order to generate a bias in the deployed state within the strut 14 which can then be utilised to assist when returning the door 3 to a stowed position.

[0028] As indicated above the pivot end 19 is suspended. In the embodiment depicted this suspension is achieved through a hanger 20 which generally extends from an upper edge of the frame 2b. In such circumstances the pivot end 19 to a degree can float upwards as will be described later into the stowed state. In order that all of the weight of the door, foldable stair or ladder as well as other components is not suspended by a single hanger 20 or other mechanism as indicated generally reinforcement 21 is provided along the length of the strut 14.

[0029] In the deployed state as depicted in figure 1 the arrangement 1 is stable through the engagement by the chamfered end 9 with the ground surface and the hinge association about the hinge end 14 between the door 3 and the frame 2a. Furthermore, the combination of the strut 14, arms 15, 16 and associations there between also resiliently present the door 3 and therefore add to stability.

[0030] It will be appreciated that generally an opposed end 2c will incorporate a latch or other mechanism to allow the door 3 to be secured in use and in the stowed state.

[0031] It will be understood that the suspension of the pivot end 19 in terms of the depth of fall for the pivot end upon as illustrated a hanger 20 will determine and limit fall of the door 3. In such circumstances it will be understood that by judicious choice of the hanger 20 or other mechanisms to provide suspension of the pivot end 19 as well as the chamfer end 9 a robust combination can be achieved for presentation of the door and therefore operational use. It will be noted that generally the hanger 20 is angled relative to an upper edge of the frame 2b in order to achieve an appropriate presentation of the pivot end 19. In such circumstances by choice of the angle of the 20 as well as the length of the hanger 20 it will be understood that the presentation angle and depth of fall about the pivot range 11 by the door 3 can be achieved. In such circumstances in terms of installation determination can be made as to the height between the frame 2 and a ground surface to be engaged by the chamfer end 9. By appropriate calculation a particular hanger 20 can then be chosen to suspend the pivot end 19 dependent upon requirements and an appropriate chamfer end created either specifically within the segment 5c or by securing a shoe having that desired angle for the chamfer end 9.

[0032] Figure 2 illustrates an initial stage of deployment with regard to the stair arrangement 1 in accordance with aspects of the present invention. Thus, initially the door 3 is released from a latch or other mechanism (not shown) in the end 2c and allowed to fall through the pivot range 11. This fall will be regulated through the bias strut 14 but nevertheless generally will also be achieved through use of an appropriate stay rod associated with the door by a user. As will described later generally, the bias strut 14 will have extended upwardly beyond the frame 2 in the stored state and so will have moved in the direction of arrowheads 30 about the mounting 18 until the pivot end 19 is suspended as illustrated upon the hanger 20 limiting further movement of the bias strut 14 and so generating an initial presentation of the door 3 relative to the frame 2 at a desired angle.

[0033] In the initial deployed state depicted in figure 2 it will be noted that the foldable ladder or stair 5 is still folded within the confines of the plan area of the door 3. The foldable ladder 5 will remain in this folded condition until an appropriate release mechanism is generally operated allowing the foldable step segments to tip over the respective hinges 7, 8 such that the abutment ends 6 engage each other to create a straight ladder or stair for use.

[0034] Figure 3 provides the next stage of deployment of the stair arrangement 1 in accordance with aspects of the present invention when the foldable ladder 5 is initially released. In such circumstances as can be seen the foldable ladder 5 will unfold typically under the weight of gravity about the hinges 7, 8 until the abutment ends 6 engage each other to create a straight ladder or stair. Generally, the segments 5a, 5b, 5c will be presented at an angle such that again gravity will urge the segments to abutment about the ends 6. It may also be possible to provide locking mechanisms or potentially slid able sleeves which can extend over the junction between the abutment ends 6 in use to retain position in the deployed state if required. It will be understood in the deployment stages depicted in figure 2 and figure 3 the arrangement of the bias strut 14, arms 15, 16 as well as their mountings 18 and at ends 22, 23 generally take the weight of the door 3 and foldable ladder 4 in use. In such circumstances these components will be formed from sufficiently robust materials to achieve such durability in operation. Typically, the frame 2, door 3 and segments 5 will be formed from a wood or metal material whilst the hinges 7, 8 as well as the arms 15, 16 will be formed from a suitable metal and with respect to the arms 15, 16 typically boxed metal segments to provide sufficient structural strength in use.

[0035] As will be appreciated the number of step treads 12 as well as the length of the foldable ladder 5 will depend upon the height to which the ladder is to extend. As indicated the chamfered end 9 will be arranged to engage a ground surface in most situations in order that a robust angular presentation of the foldable ladder 5 in its deployed state will be achieved. The frame 2 will have a size to accommodate the necessary ladder segments 5a, 5b, 5c and normally an odd number of segments will be provided to allow easy forward deployment of the arrangement in use. It will be appreciated that three segments 5a, 5b, 5c have particular advantages in terms of reducing the number of hinges 7, 8 required and therefore providing a stair or ladder in an arrangement 1 in accordance with aspects of the present invention which is appropriately robust in use.

[0036] Figure 4 provides a plan view of the arrangement 1 in a stowed state. In such circumstances the door 3 extends substantially parallel across the frame 2 and as indicated above is generally secured through a latch or other mechanism in an end 2c opposite the end 2a of the frame 2 in which the hinge end 4 is created. As can be seen the foldable ladder 5 generally extends within the plan area of the door 3 and is stowed through an appropriate latch mechanism as described above.

[0037] The bias strut 14 is generally extended upwards away from the hanger 20 and support 21 as will be described later with the hinge arm brackets hidden behind the door arm brackets and the door arm 16 nestling within each other and the side frame width. In such circumstances from below all that would be noted is the door 3.

[0038] Figure 5 provides a perspective view of the arrangement 1 in a stowed state as depicted in figure 4. In such circumstances as indicated above generally the bias strut 14 extends upwardly about the elbow created at the pivot end 19 with the hinge arm 15. In such circumstances the bias strut 14 is not supported upon the hanger 20 and is suspended between the pivot end 19 and an end 17 associated with the mounting 18. In this condition as described above generally a latch (not shown) is provided in the frame end 2c to retain the door 3 within the frame 2.

[0039] Figure 6 provides a side illustration of the arrangement 1 depicted in figure 4 and figure 5 with a front lateral part of the frame rendered transparent for illustration purposes. Thus, as can be seen the bias strut 14 extends upwardly as indicated between the pivot end 19 and a mounting end with the frame 2. As can be seen generally the hinge arm 15 is arranged to be substantially vertical above the mounting at the end 22. Such a configuration facilitates retention of the door 3 within the frame 2 with less stress upon the components in use.

[0040] The hanger 20 which allows suspension of the pivot end 19 as illustrated and described previously is generally at an angle to properly engage part of the hinge arm 15 or the bias strut 14 to limit fall of the pivot end 19 and to suspend the end 19 in deployed use.

[0041] It will be noted that the bias strut 14 as described previously in the embodiment illustrated comprises a gas or hydraulic piston arrangement. In such circumstances in the stored state it will be noted that the piston is withdrawn and generally will be relaxed. However, upon deployment a rod portion 40 of the bias strut 14 will push into the strut 14 creating a gas pressure. This gas pressure initially will restrict the speed of rotation of the door 3 about the hinge end 4. The compression provided within the bias strut 14 will also store energy such that upon return to the stored state as depicted in figures 4 to 6 this compression will facilitate and assist lifting of the door with the ladder in use. The alternative is to provide a suction vacuum rather than a compression pressure to provide regulation and/or assistance.

[0042] It will be noted that a pivot association 41 is provided between the door arm 16 and the hinge arm 15. The association 41 is part way along the distance between the pivot end 19 and a hinge pivot 42 of the hinge arm 15. The positioning of the association 41 will provide variation with respect to the mechanical lever advantage created in terms of regulating rotation of the door 3 about the hinge end 14 as well as assistance with regard to returning the door 3 about the hinge 14 to a stowed state as depicted in figures 4 to 6.

[0043] As described above generally pivots are created at the pivot end 19, the mounting end 17 of the bias strut 40 as well as at the mountings at the ends 22, 23 with the door 3 and as indicated above at the association 41 between the hinge arm 15 and the door arm 16. These pivot movements may be generally unrestricted or alternatively, rotation ranges may be determined through use of detents associated either side of the pivot to again constrain movement and therefore presentation of the door 3 in use.

[0044] As described above generally the pivot end 19 is suspended through use of a hanger 20. The length of this hanger 20 as well as its angular presentation may be utilised to limit the degree of fall by the pivot end 19 and therefore presentation of the door 3. A number of different lengths and angular presentation hangers 20 may be provided to adjust the degree of fall for the door through rotation about the pivot end 4 in use. Alternatively, the hanger 20 may be moved in the direction of arrowheads 43 to again adjust the angular presentation and therefore the suspension position for the pivot end 19 in use.

[0045] Aspects of the present invention utilise provision of a bias strut and typically a gas strut or hydraulic ram, to both regulate deployment of a stowed ladder or stair through a frame 20 formed in a loft aperture. By use of hinge arms 15, 16 and the mechanical advantage created by the association between these arms the benefits of a bias strut are regulated dependent on particular operational conditions and in particular to ensure during deployment controlled rotation about the hinge end 4 and assistance is provided through the stored bias energy created within the bias strut. Normally movement of the door would be achieved through a rod which will engage the door to lift and/or release an appropriate latch mechanism for the door at the end 2c as well as with regard to the foldable ladder or stair 5.

[0046] Modifications and alterations to aspects of the present invention will be appreciated by those skilled in the art. Thus, as illustrated the hinge arm 15 and door arm 16 are generally formed from straight components. However, in order to create different rotational paths as well as potentially strengthening of these arms a degree of curvature may be created. Furthermore, in order to facilitate both regulation of deployment by rotation of the door 3 about the hinge end 4 as well as possibly provide mechanical advantage some or all of the pivot associations provided at the ends 22, 23 as well as the association 41 and the pivot end 19 association with the hinge arm 15 and the mounting end 17 with the mounting 18 may include friction braking to limit rotation and/or provide a spring wind up mechanism for rotational control as well as potential mechanical assistance in returning the door 3 to its stored state.

[0047] To aid stability a hand rail may be present to one side of the frame or upon it. The hand rail may comprise a loop of tubular material extending upward to provide a grip as a user ascends and descends the ladder or steps. The hand rail must be appropriately presented but need to be of relatively simple construction and arranged for easy installation.

[0048] It will be understood that the arrangement described above essentially depends upon its own weight and gravity to remain deployed with the ladder or steps extending downward. Unfortunately, in some circumstances, particularly during the initial stages of stowage when the ladder or steps is folded and lifted it is possible for the mechanical advantage of the pivots, levers and gas strut bias element to 'run away' that is to say lift quickly and as perceived uncontrollably. Such re-closure to the stowed state may also occur with little if any perceived intention by a user if the ladder or steps are inadvertently knocked etc. One approach may be to add further bias weight to the bottom of the steps but this may have other consequences with respect to the force need during initial stages to deployment to the unfolded state. A preferred approach to resist inadvertent return or folding is to prove a gripper associated with the suspended pivot. The gripper will ensure that a positive initiation force is required to begin folding to the stowed or the stored state about the bias strut and pivot ends/arms. The gripping force of the gripper would need to be over come before action about the pivots by the struts and user actions to return the arrangement to the stowed state.

[0049] Figure 7 provides a front cross-section of a gripper 100 in accordance with aspects of the present invention. The gripper 100 is shown in the form of a clip which embraces a pivot or other part of the strut/pivot combination (shown by broken line 101) to hold position until a release force in the direction of arrowhead 103 is applied to overcome the gripping force of the gripper 100. The gripper 100 as illustrated in Figure 7 is a pipe retainer clip but it will be understood what is generally required is some means of applying a gripping force to render it necessary to deliberate apply a release force to prevent inadvertent release. This could be achieved in a number of ways.

[0050] The gripper 100 is presented upon a bracket 104 secured to part of a frame 105 in accordance with aspects of the present invention. The frame 105 also provides the structure upon which the struts and pivots arms are mounted to achieve operation in accordance with aspects of the present invention. Alternatively, the gripper could be directly secured to the frame but this may make it more difficult to achieve a robust position.

[0051] The gripper 100 may be used instead of a hanger 20 or in addition to a hanger to ensure adequate presentation of the pivot ends and struts in accordance with aspects of the present invention. The gripper in such circumstances may be orientated and angled as required.

[0052] Generally, the gripper will be made from a plastics material but could also be made of a suitable metal.

[0053] Whilst we endeavour 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.

Claims

1. A stair arrangement comprising a frame and a door associated with the frame at a hinge end, the frame presenting a bias strut with a suspended pivot end secured to a hinge arm which extends to a portion of the door displaced from the hinge end, a door arm extending from towards an opposite end of the door to the hinge end to a pivot position upon the hinge arm, the pivot position towards the pivot end association of the hinge arm to define a mechanical lever to regulate with the bias strut pivot movement of the door about the hinge end.

2. An arrangement as claimed in claim 1 wherein the suspended pivot end is suspended upon a hanger to limit fall as the door moves about the pivot end.

3. An arrangement as claimed in claim 2 wherein the hanger is angled relative to an upper edge of the frame to present the pivot end when engaged by the bias strut.

4. An arrangement as claimed in any of claims 1 to 3 wherein the arrangement includes a gripper to engage the suspended pivot end for retention of position.

5. An arrangement as claimed in any preceding claim wherein the bias strut remains substantially within a width of the frame defined by an upper edge of the frame and a lower edge of the frame.

6. An arrangement as claimed in any preceding claim wherein the bias strut is supported at a displaced position from the pivot end.

7. An arrangement as claimed in claim 6 wherein support is provided by a hanger.

8. An arrangement as claimed in any preceding claim wherein a last step segment has a chamfer end and the chamfer end defines a step angle when in engagement with a surface.

9. An arrangement as claimed in claim 8 and any claim dependent therein wherein the arrangement may be associated with one of a range of chamfer ends defining respectively different step angles.

10. An arrangement as claimed in claim 8 and any claims dependent thereon wherein the step angle determines a limit of pivot movement about the hinge end by the door.

11. An arrangement as claimed in any preceding claim wherein the bias strut and hinge arm are arranged in a side by side configuration with the door arm.

12. An arrangement as claimed in any preceding claim wherein the door arm is extendible for variation upon installation of the stair arrangement and is lockable for use subsequent to installation.

13. An arrangement as claimed in claim 12 when dependent upon claim 8 wherein the door arm is of variable length dependent upon the chamfer end in engagement with the surface.

14. An arrangement as claimed in claim wherein the bias strut comprises a gas spring.

15. An arrangement as claimed in any preceding claim wherein the bias strut is secured to an upper edge of the frame through an angle bracket.

Drawing