AU2015201567A1 - Stairway system and retractable stairway for vehicles - Google Patents

Abstract

A stairway system 10 for a vehicle includes a stairway 12 pivotably retractable about a pivot axis of a main pivot arrangement 46 by a retraction mechanism including an actuator 40. The stairway has treads 14a... 14n each connected to a support structure 18 by a pivot arrangement 16. A tread levelling mechanism 49 maintains an upper surface of the respective tread level during at least part of a stairway retraction phase. The tread levelling mechanism can include a tread levelling control arm connected to each tread and to a control link 60 at the top tread. The link 60 supports a guide roller 56 which contacts a control guide 58 during retraction or deployment to control tread levelling. A distal end of the stairway has a foot or skid 28. 14f 14e 14d 48 14c 14b 44e 14a 38 18Fig 1 36,38 14f 14b4 14c 28 54 Fig2

Description

1 STAIRWAY SYSTEM AND RETRACTABLE STAIRWAY FOR VEHICLES FIELD OF THE INVENTION [0001] The present invention relates to a stairway system and a retractable stairway for vehicles. BACKGROUND TO THE INVENTION [0002] Many vehicles, particularly in the resources and mining industries, have a high ground clearance requiring stairs or a ladder for safe user access to operate the vehicle. [0003] Known stairs or ladders are typically designed for level ground deployment. Typically such stairs or ladders deploy by rotating downwards from a retracted position. As a safety feature, often a lockout system is provided preventing the vehicle from being started or moved until the stair or ladder is fully retracted to a safe position. This prevents people or equipment on the ground from being injured or damaged by the stair or ladder if the vehicle moves. Also, this prevents damage to the stair or ladder. [0004] Such stairs or ladders are deployed often with the vehicle partly in a dip or hole in the ground, such as a drainage channel, and thus the treads are not level when the stair or ladder is fully deployed because the vehicle is leaning over relative to the ground contact point for the stair or ladder. [0005] Other times, the stair or ladder is deployed onto a high point of ground, thereby not allowing the stair or ladder to fully deploy. [0006] In either case, the treads of the stair or ladder are left at a dangerous angle when the user wishes to access or alight from the vehicle. This makes 2 access or egress form the vehicle unsafe for a user, potentially resulting in a slip or fall injury for the user. [0007] Some stairs or ladders are designed not to contact the ground from the vehicle when deployed. Consequently, such stairs or ladders can become damaged if the ground is higher than anticipated or the user is unaware of when the stair or ladder is deployed. This results in vehicle downtime, and related loss of productivity, whilst the stair or ladder is repaired or replaced. [0008] Furthermore, stairs or ladders that do not reach the ground leave a step gap for the user to negotiate to reach the first step when first access the vehicle or a gap to jump down from when alighting form the vehicle. Consequently, the user is at risk of injury from having to negotiate that gap. [0009] It has therefore been found desirable to provide a retractable stairway system for a vehicle gives safer access or egress from the vehicle. SUMMARY OF THE INVENTION [0010] With the aforementioned in mind, an aspect of the present invention provides a stairway system for a vehicle, the stairway system including a stairway pivotably retractable about a pivot axis of a main pivot arrangement from a downwardly deployed position providing access to and egress from the vehicle and an upwardly retracted position preventing access to or egress from the vehicle when the vehicle is in use, the stairway including multiple treads, each of the multiple treads connected to a support of the stairway by a tread levelling mechanism, the tread levelling mechanism maintaining an upper surface of the respective tread level during at least part of a stairway retraction phase. [0011] In the present specification, the term 'level' means horizontal or generally horizontal as a 'normal' tread of a stair would be when in use.

3 [0012] A further aspect of the present invention provides a stairway system for a vehicle, the stairway system including a stairway pivotably retractable about a pivot axis of a main pivot arrangement from a downwardly deployed position providing access to and egress from the vehicle, and an upwardly retracted position preventing access to or egress from the vehicle when the vehicle is in use, the stairway including multiple treads, and at least one ground contact portion at a distal end of the stairway relative to a proximal end of the stairway adjacent the pivot axis, and a stairway control system and means to detect when the ground contact portion has contacted the ground or an object, or detects that the stairway is fully deployed, and halts controls the stairway to cease deployment. [0013] The stairway is preferably retracted by retraction mechanism including at least one hydraulic, pneumatic or electrically operated actuator. More preferably the retraction mechanism is operated from one or both of a cab mounted control on the vehicle for use by the vehicle operator to egress the vehicle and an external control on the vehicle and relatively close to the ground e.g. on the bumper or lower body of the vehicle, for operation by a person wishing to deploy the stairway to access the vehicle. [0014] Preferably the tread levelling mechanism maintains the treads level only partway through stairway retraction. [0015] Preferably the treads remain level until the stairway is retracted to a generally horizontal position. For example, if the stairway is in a deployed position angled downward approximately 70 degrees from horizontal, once the stairway is rotated about the pivot axis to a generally horizontal position, the treads have then reached their maximum ability to remain level and the tread levelling mechanism ceases to maintain the treads level. After that point in the retraction phase, the treads are non-level and the stairway rotates to a fully retracted (stowed) position, which is preferably substantially vertical or at least upright.

4 [0016] Each of the treads may be connected to the respective tread support by at least one tread pivot. [0017] The tread support member(s) may include at least one longitudinal beam arrangement extending from adjacent the main pivot arrangement to adjacent a/the at least one ground contact portion. Each of the treads may be pivotably mounted to the at least one longitudinal beam arrangement. [0018] Each of the treads to be maintained level during the initial phase of retraction may include a portion connected to a control arrangement. Preferably the control arrangement includes at least one link member extending between adjacent treads. [0019] Preferably the control arrangement rotates the treads relative to the at least one support arrangement during the initial retraction of the stairway. [0020] The treads are therefore automatically levelled whilst the stairway is deployed and up to a partially retracted position. Once the stairway reaches a predetermined partially retracted position, the treads cease levelling and are allowed to become angled from level self levelling. [0021] During the final phase of retraction of the stairway, the treads can become disposed relatively flat and inline along the support arrangement, thereby reducing overall space required to stow the ladder upright and adjacent the vehicle. [0022] Preferably the stairway includes at least one handrail to aid a user when ascending or descending the deployed stairway. The handrail(s) may be fixedly attached to a portion of the stairway, or may collapse down during retraction and extend out for use during deployment of the stairway.

5 [0023] It will be understood that the term 'retraction' used in the specification refers to the stairway rotating about the main pivot between the deployed and retracted (stowed) positions and vice versa. [0024] Preferably the vehicle is a vehicle for use in the resources or mining industry, such as an earthmoving vehicle or other large transport vehicle with high ground clearance and need of stairs for a user to gain access to and egress from the vehicle for normal operations. [0025] Preferably the automatic tread levelling arrangement maintains the treads level from 100mm below normal ground level to around 900mm above normal ground level, and more preferably between normal ground level and 900mm above normal ground level. [0026] Being able to detect that the stairway has reached the ground and stop further deployment ensures that the stairway is safely deployed, reduces strain on mechanical and hydraulic/pneumatic/electrical components, and reduces waste of energy. [0027] The stairway control system may control deployment and/or retraction, and may include on or more sensors to detect sufficient deployment of the stairway when the stairway contacts the ground. Such at least one sensor may include at least one contact or proximity sensor directly detecting presence of the ground, or may include at least one pressure or resistance sensor, such as in a respective hydraulic/pneumatic or electrical control system effecting deployment of the stairway. [0028] For example, a hydraulic or pneumatic system my detect build up of pressure or reduced reduction in pressure in the system do to the distal end of the stairway contacting the ground.

6 [0029] The distal end of the stairway may include a ground contact means, such as a foot plate, thereby providing a skid to accommodate change in contact with the ground if the stairway slides sideways while the stairway is deployed and due to movement of the vehicle. [0030] Preferably the foot plate may be of metal, and may preferably be curved with outer end portions higher than a central portion designed to first contact the ground. Having a curved foot plate improves the 'skid' or movement of the contact point over the ground and accommodates for bumps and rocks in the ground without the stairway digging into the ground and becoming damaged. [0031] Furthermore, when the skid contacts the ground, a user is assured that the treads are level and the first tread is at a safe and correct step height. BRIEF DESCRIPTION OF THE DRAWINGS [0032] One more embodiments of the present invention will hereinafter be described with reference to the accompanying drawings, in which: [0033] Figure 1 shows a perspective view of a stairway system for mounting to a vehicle in accordance with an embodiment of the present invention. [0034] Figure 2 shows a side view of the stairway system according to the embodiment shown in Figure 1. [0035] Figures 3 shows a side view of the stairway in alternative fully deployed (A) and partially retracted (B) positions according to an embodiment of the present invention. [0036] Figures 4 to 6 show stages of retraction of the stairway from a fully deployed position (figure 4) through a partially retracted position (figure 5) to a 7 fully retracted position (figure 6) according to an embodiment of the present invention. [0037] Figure 7 shows detail of a tread levelling mechanism incorporated in an embodiment of the present invention. [0038] Figure 8 shows a portion of the stairway system revealing part of the tread levelling mechanism according to an embodiment of the present invention. DESCRIPTION OF PREFERRED EMBODIMENT [0039] The embodiment of the present invention shown in Figures 1 to 8 provides a stairway system 10 including a stairway 12 having a number of treads 14a..14n as required for a given application. [0040] It will be appreciated that the exact number of treads will vary between vehicle applications depending on the required length of the stairway and tread separation. [0041] The treads 14a....14n are pivotable connected by respective tread pivots 16 to a support structure 18. The support structure includes a longitudinal shallow C- channel 20 providing an upper cover plate 22 between two parallel longitudinal plate beams 24, 26 to which the treads are pivoted. [0042] The distal end of the stairway has a foot or skid 28. The foot or skid is curved so that outer ends 30, 32 are above the central portion 34, which beneficially allows the foot or skid to accommodate for uneven ground and to prevent the foot or skid being damaged if the foot or skid moves laterally. [0043] A handrail 36, 38 is mounted to either side of the stairway.

8 [0044] During an initial phase of retraction, the treads remain horizontal (level). During a latter phase of retraction, the treads lay relatively flat with respect to the support structure, and are no longer maintaining a level (horizontal) step surface. However, at this latter stage the stairway is sufficiently retracted that a user can no longer be on or be using the stairway. [0045] Thus, the stairway treads remain level during a useable angle of deployment of the stairway i.e. the stairway could be deployed at an angle below horizontal (thereby allowing for very uneven ground) with the treads remaining level. [0046] Treads are maintained level by a tread levelling mechanism 49 (see, for example, figure 8). This tread levelling mechanism includes a tread levelling control arm 50 pivotably attached via a respective control arm to tread pivot 16. The control arm 50 is connected to a control link 60 via a control arm to link pivot 62. [0047] The link 60 is connected to the pivotable top tread 14e (the actual tread number depends on the total number of treads required for a given application). The link also supports a guide roller 56. The guide roller contacts a control guide 58 during the retraction and deployment phases. [0048] As the stairway retracts from its fully deployed position (A), the control guide roller progresses in contact along the control guide. That movement is translated via the control link to the tread levelling control arm and thence via the control arm to tread pivots to the respective treads. [0049] As the distal end of the stairway rises during retraction, the top (upper) tread rotates about the main pivot and actually lowers a small amount during that movement, the top tread is maintained level by contact of the guide roller on the control link with the control guide. That levelness is translated via connection of 9 the control link through the tread levelling control arm to each tread pivotably connected to the tread levelling control arm. [0050] The actuator 40, preferably a hydraulic or pneumatic ram, can have one end 42 thereof connected partway along the length of the stairway and another end 44 thereof connected to the vehicle. Thus, extension of the ram causes the stairway to retract by rotation about the axis 48 of the main pivot arrangement 46. Release of pressure within the ram allows the stairway to deploy under gravity as pressure decreases in the ram and associated hydraulic/pneumatic system. [0051] One or more pressure sensors can detect a change in the drop in pressure, or can detect pressure from actual contact with the ground, and thereby actuate the control system to prevent further deployment of the stairway, such as by locking out the hydraulic or pneumatic system so that the pressure does not change and thus further deployment of the ladder is halted. [0052] Figure 2 shows a side view of the stairway system 10. The stairway 12 is connected to the vehicle (not shown) by the main pivot arrangement 46. [0053] A link member 50 connects each of the treads to ensure that each tread member moves in concert with the other tread members to remain level. [0054] By way of illustration of the tread levelling capability of the stairway 12, Figure 3 shows the stairway 12 mounted to the front of a vehicle 52. The stairway is shown at two alternative positions - at a deployed position marked A and at a partially retracted position marked B. For the purposes of illustration of this embodiment, the handrails 38,40 are not shown. [0055] In the deployed position A, which is just one example of a fully deployed position, the stairway is angled downwards from the vehicle 52 at 450 angle with respect to vertical.

10 [0056] At position B, the stairway is partially retracted to an angle of approximately 200 from horizontal i.e. approximately 700 from vertical. The treads 14a... 14n remain horizontal as the stairway moved from the fully deployed position A, through the partially retracted position B, to the further partially retracted position C. During ongoing retraction after position C, the treads have fully pivoted with respect to the support structure, and therefore do not remain horizontal (level) for the final phase of retraction to the fully retracted position D (see Figure 6). [0057] Figures 4 to 6 show phases of retraction of the stairway from the fully deployed position A (Figure 4) through a partially retracted position B (Figure 5) to the fully retracted position D (Figure 6). As can be seen, the treads 14a... 14n remain level (horizontal) with respect to the ground level (or ground plane) GL until the tread levelling mechanism reaches its limit of tread level adjustment and the treads no longer remain level during the final phase(s) of retraction. [0058] As shown in figure 7, the control guide roller 56 progresses along the contact surface of the control guide 58. The top tread 14e (1 4n) lowers slightly as it rotates about the main pivot 46, but still remains level for the initial phase of retraction. Once the stairway 12 has sufficiently partially retracted (e.g. above horizontal) so that a user would not use the stairway, the control guide roller ceases to contact the control guide and the treads then lay relatively flat with respect to the elongate support structure to which the treads are pivoted. In this way, the treads can store relatively flat when the stairway is stowed upright, but become level, and then remain level, during the latter phase of deployment. [0059] In use, a control system on the vehicle, such as a hydraulic, pneumatic or electrical control system, enables optional gravity lowering or power lowering of the stairway depending on the required application of the stairway system specified for the vehicle.

11 [0060] Preferably a hydraulic control system is utilised to control a hydraulic ram 40 connected between the stairway and the vehicle. A hydraulic manifold can be provided incorporating the one or more solenoids, valving, timers, or combinations thereof, to control flow of hydraulic fluid to and from the ram for respective stairway raising (retraction) and lowering (deployment) actions. Preferably extension of the ram causes raising of the stairway, and retraction of the ram allows deployment of the stairway. [0061] The control system can be operated from the cab of the vehicle or from an external controller provided on the vehicle nearer to the ground so that an operator can deploy the stairway in order to obtain access to the vehicle. The external and cab based controllers can include electrical switches controlling operation of the valves and/or solenoids associated with manifold. [0062] For the up function when raising the stairway, a limit switch can be provided that will centre a control valve and essentially lock hydraulic pressure in the up and down side hydraulic sides of the ram, thereby holding the stairway in the retracted or other chosen position. A pressure accumulator can be provided to give residual holding pressure in the stowed position. [0063] For a power down (deployment function, a pressure limiting valve and a timer can be used to provide more controlled deployment of the stairway. If the stairway is deployed by gravity i.e. the stairway is not hydraulically or otherwise power deployed, hydraulic pressure is control released (which can be by controlled flow of hydraulic oil to a reservoir). One or more dampers can be provided to damp motion of the treads during their relative motion with respect to the support structure. Preferably such one or more dampers includes at least one gas or hydraulic strut operatively mounted on the stairway between the support structure and the treads, more preferably having one end mounted to the tread levelling control arm and another rend mounted to the support structure.

Claims (16)

1. A stairway system for a vehicle, the stairway system including a stairway pivotably retractable about a pivot axis of a main pivot arrangement by a retraction mechanism from a downwardly deployed position providing access to and egress from the vehicle to an upwardly retracted position preventing access to or egress from the vehicle when the vehicle is in use, the stairway including multiple treads, each of the multiple treads connected to a support member of the stairway by a tread levelling mechanism, the tread levelling mechanism maintaining an upper surface of the respective tread level during at least part of a stairway retraction phase.

2. A stairway system for a vehicle, the stairway system including a stairway pivotably retractable about a pivot axis of a main pivot arrangement by a retraction mechanism from a downwardly deployed position providing access to and egress from the vehicle to an upwardly retracted position preventing access to or egress from the vehicle when the vehicle is in use, the stairway including multiple treads, and at least one ground contact portion at a distal end of the stairway relative to a proximal end of the stairway adjacent the pivot axis, and a stairway deployment control system which detects when the ground contact portion has contacted the ground or an object, or detects that the stairway is fully deployed, and halts controls the stairway to cease deployment.

3. A stairway system according to claim 1 or 2, the retraction mechanism including at least one hydraulic, pneumatic or electrically operated actuator.

4. A stairway system according to claim 1 or 2, wherein the retraction mechanism includes a control means to operate the system provided at one or both of a cab mounted control on the vehicle for use by the vehicle operator to egress the vehicle and an external control on the vehicle and relatively close to the ground. 13

5. The stairway system according to claim 1, the tread levelling mechanism including levelling means arranged and configured to maintain the treads level only partway through stairway retraction.

6. The stairway system according to claim 5, the treads remaining level until the stairway is retracted to a generally horizontal position, the treads thereafter ceasing to remain level during the remainder of the retraction.

7. The stairway system according to claim 1 or 2, each of the treads connected to the respective tread support by at least one tread pivot.

8. The stairway system according to claim 7, wherein the respective tread support includes at least one longitudinal beam arrangement extending from adjacent the main pivot arrangement to adjacent a/the at least one ground contact portion.

9. The stairway system according to claim 8, wherein each of the treads is pivotably mounted to the at least one longitudinal beam arrangement by a tread pivot arrangement.

10. The stairway system according to claim 8 or 9, each of the treads to be maintained level during the initial retraction including a portion connected to a control arrangement, the control arrangement including at least one link member extending between and connecting adjacent treads.

11. The stairway system according to claim 1 or 2, including at least one handrail to aid a user when ascending or descending the deployed stairway.

12. The stairway system according to claim 2, the control system including on or more sensors to detect sufficient deployment of the stairway when the stairway contacts the ground. 14

13. The stairway system according to claim 12, the at least one sensor including at least one contact or proximity sensor directly detecting contact with the ground or at least one pressure or resistance sensor indirectly detecting contact between the stairway and ground.

14. The stairway system according to claim 13, the control system including a hydraulic or pneumatic system and the at least one pressure sensor to detect build up of pressure or reduced reduction in pressure in the system do to the distal end of the stairway contacting the ground.

15. The stairway system according to claim 14, wherein the distal end of the stairway includes a ground contact means, such as a foot plate, thereby providing a skid to accommodate change in contact with the ground.

16. The stairway according to claim 1, the tread levelling mechanism including an inter-cooperating control guide roller and guide arrangement wherein moving contact of the guide roller with the guide during deployment or retraction, or both deployment and retraction, of the stairway, causes the treads to remain level through pivots and linkages of the tread levelling mechanism. DANTENG PTY LTD WATERMARK PATENT AND TRADE MARKS ATTORNEYS