Patent Publication Number: US-2004055820-A1

Title: Ladder safety device

Description:
FIELD OF THE INVENTION  
       [0001] This invention relates to an apparatus and method for increasing the safety of ladder use. In particular the invention relates to an apparatus and method for holding a ladder in a secure and generally safe position while in use.  
       BACKGROUND OF THE INVENTION  
       [0002] Ladders are notorious for being the focal point of life threatening accidents in both domestic and industrial settings. The element of risk may be increased by the nature of the ladder, its length in use, the stability of the ground support surface and the nature and shape of the support structure at its upper end.  
       [0003] In the absence of a level base surface, a ladder will often adopt a laterally sloped attitude. The effect of this slope is to move the centre of gravity of the ladder and user away from the rung support structure and, in some cases, to a point outside a lateral rail of the ladder. At this stage, the user is essentially relying on frictional engagement between the top end of the ladder and a support structure to prevent the ladder sliding sideways. In another respect, danger arises when a ladder is particularly steeply sloped and approaching the vertical in a front to back direction. In this circumstance, it is possible for the ladder to disengage from its support surface and tilt backwards carrying the user into a radially arcing fall away from the support surface.  
       [0004] The relative experience of a user may also be important in the risk factors of a ladder with home handymen being particularly susceptible to accidents, although this may be offset by industrial use which often occurs in more challenging environments.  
       [0005] It would be advantageous to provide a ladder stabilising or securing apparatus which tended to counteract at least some of the instability of a ladder during use.  
       SUMMARY OF THE INVENTION  
       [0006] Throughout this specification, unless the context requires otherwise, the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element or integer or group of elements or integers but not the exclusion of any other element or integer or group of elements or integers.  
       [0007] In a first aspect the invention resides in a ladder stabilising device comprising:  
       [0008] first engagement means adapted to releasably engage a first structure;  
       [0009] a connection member connected to the first engagement means; and  
       [0010] second engagement means adapted to engage the first structure or a second structure, the second engagement means connected to the connection member at a position spaced from the first engagement means.  
       [0011] Preferably the first engagement means is clamping means. Suitably the clamping means is an adjustable clamping member. The clamping member may comprise opposed jaws, movable relative to each other. The opposed jaws may be resiliently biased to a closed position. The clamping member may include screw threaded adjusting means for adjusting the laws relative to each other.  
       [0012] The clamping means may also suitably include locking means for locking the jaws in pressured contact with the first structure. The locking means may be a lover activated over-centre locking device.  
       [0013] The first and second engagement means may be formed of metal, plastic, rubber or other suitable material. The second engagement means is preferably adapted to releasibly engage the first or second structure.  
       [0014] The first structure may be a building or feature thereof. The first structure may be a gutter of the building. The first structure may be any one of a post, cable, wire or other suitable supportive structure. The first structure may be the ladder itself. The second structure may be any suitable alternative support structure other then the first structure.  
       [0015] The ladder stabilising device may include a lateral support member for providing lateral support to the ladder. The lateral support member may be formed integrally as part of one of the jaws. Alternatively the lateral support member may be releasably engageable with the jaw. The lateral support member may be adapted to bracket a ladder side rail. A gap provided for bracketing the ladder side rail may be adjustable. The lateral support member may be a bracket formed from a plate member. Alternatively the lateral support member may be a bracket formed of elongate material such as wire.  
       [0016] The lateral support member may be adjustably engaged with the jaw of the clamping member to facilitate variation of the bracket space provided to received the ladder rail.  
       [0017] Alternatively, the first engagement means may be a u shaped member adapted to locate over the first structure or feature thereof. The u shaped member may have locking means for fixing the u shaped member to the gutter. The looking means may be a screw operated locking means.  
       [0018] The connection member may be rigid or semi-flexible. The connection member is preferably flexible throughout its length. The connection member may be semi-flexible. The flexible member may be formed from a strap, webbing, chain or rope or other suitable material. The connection member may be formed of rod section with locking bell joints or hinges. The connection member may be formed from an elasticised or rubberised, material.  
       [0019] The connection member may be permanently connected to the first engagement means and second engagement means or alternatively releasably connected to the first and/or second engagement means.  
       [0020] Preferably the second engagement means is a second clamping member. The clamping member is preferably an adjustable clamping member. The adjustable second clamping member may comprise opposed jaws. The opposed jaws may be resiliently biased to a closed opposition. The second clamping member may include screw threaded adjusting means for adjusting the jaws. Preferably the second clamping member includes locking means for locking the jaws into position. The locking means may be a lever activated over-centre locking means.  
       [0021] In one form, the second engagement means may be a permanent fixing to the ladder.  
       [0022] Preferably the second engagement member is a slide member for releasably engaging a side rail of the ladder. The slide member may be adapted to slidingly engage one or more adjustment rails located on a ladder rail. Preferably the slide member has position locking means for locking the slide member in a preferred position. The position locking means may be a screw thread operated device. The slide member may comprise a sleeve member adapted to slide over at least part of a perimeter of the ladder rail. The sleeve member may a slotted tube member. Alternatively the sleeve member may be an L shaped sliding member.  
       [0023] In one embodiment both the first engagement means and second engagement means are formed to slidingly engage the ladder rails, each to a respective rail and each further comprises gutter engagement means. The gutter engagement means may be a gutter engaging slot.  
       [0024] The second engagement means may be a u shaped member adapted to locate over the first and/or second structures or a feature thereof. The u shaped member may include screw operated locking means.  
       [0025] The second engagement means preferably further comprises length adjustment means for varying the length of operative connection member. The length adjustment means may be a buckle device. Alternatively, or additionally, the length adjustment means may be a retraction device.  
       [0026] Preferably the ladder stabilising device further comprises tensioning means for applying tension to the connection member. The tensioning means may comprise a ratchet and lever drum assembly or a tensioned drum adopted to retract the connection member.  
       [0027] In a second aspect, the invention resides in a method of stabilising a ladder, said method comprising:  
       [0028] fixing a first engagement means of a stabilising device to a first structure;  
       [0029] positioning a connection member of the stabilising device in a stabilising position adjacent a support structure, said support structure supporting an upper region of the ladder; and  
       [0030] fixing a second engagement means of the stabilising device to the first structure or a second structure.  
       [0031] The support structure may comprise the first or second structure or may be a separate structure supporting the upper ladder.  
       [0032] The method may include the step of positioning a bracket device to provide lateral stability to an upper region of the ladder.  
       [0033] The method may further include the step of tensioning the flexible connection member.  
       [0034] In one form the method includes the further step of sliding the second engagement means along a rail of the ladder to a suitable position and releasably fixing the second engagement means at that position.  
       [0035] The second engagement means is preferably a slotted sleeve, an L shape sleeve or adapted to cooperate with one or more adjustment rails located on a rail of the ladder. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0036]FIG. 1 is a top view of a first embodiment of a ladder stabilising device of the present invention.  
     [0037]FIG. 2 is a perspective view of the ladder stabilising device of FIG. 1 in operation.  
     [0038]FIG. 3 is a perspective view of a second embodiment of a ladder stabilising device of the present invention in use.  
     [0039]FIG. 4 a front view of the arrangement of FIG. 3.  
     [0040]FIG. 5 is a perspective view of a third embodiment of a ladder stabilising device of the present invention in operation.  
     [0041]FIG. 6 is a perspective view of a fourth embodiment of a ladder stabilising device of the present invention.  
     [0042]FIG. 7 is a cross sectional view of the ladder rail of FIG. 6.  
     [0043]FIG. 8 is a perspective view of a tensioning device of FIG. 6.  
     [0044]FIG. 9 is a perspective view of a fifth embodiment of a ladder stabilising device of the present invention.  
     [0045]FIG. 10 is a top view of a variation of a second end of the ladder stabilising device of FIG. 9.  
     [0046]FIG. 11 is a front view of the device of FIG. 10.  
     [0047]FIG. 12 is a perspective view of a sixth embodiment of the ladder stabilising device of the present invention.  
     [0048]FIG. 13 is a front view of a ladder stabilising device in use. 
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS  
     [0049] Throughout the description like numbers refer to like features. Referring to FIG. 1 there is seen a first embodiment of a ladder stabilising device  10  comprising a first engagement means in the form of first clamp  11 , a connection member in the form of cable  12  and a second engagement means in the form of second clamp  13 . First clamp  11  comprises first jaw  14  and second jaw  15  which are opposed. Second jaw  15  is hingedly mounted at pivot  16  so that it may be moved towards and away from the first jaw  14 . A screw threaded adjustment device  17  is provided to permit rotation of disk  18  to advance or retract the threaded shaft  19  to position the jaws  14 ,  16  in contact with the structure to which the device is to be attached. The first clamp  11  also includes locking means in the form of a lever  20  which when depressed activates cam  21  to rotate tension bar  22  and thereby indirectly apply extra tension through the screw threaded adjusted device  17  onto the second jaw  15 .  
     [0050] Clearly the first clamp  11  is well adapted to locate around a first structure such as a circular structure like a pipe or to be placed over the lip of a gutter or indeed to be located in operative position with any structure that will fit between its fully deployed jaws. It may be applied a ladder with which it is used.  
     [0051] The connection member  12  is shown as a cable in this view and it is permanently connected at a first end  23  to the first clamp  11 . The cable  12  may be formed from any suitable material such as rubber, wire or rope or similar. A second end  24  is attached to the second clamp  13 . The second clamp  13  is configured in this view in a different form to the first clamp  11   i  although this is not essential. The second clamp has opposed jaws  25 ,  26  which are moveable relative to each other and includes an initial adjustment device in the form of a threaded shaft  27  for providing an initial apposition of the jaws  25 ,  28  into contact with a structure to which they are attached. A further locking lever  28  is provided to pressurise the contact between the jaws and the structure to which they are in contact. The locking lever may activate a cam type locking device or any other suitable means known to a skilled addressee. The locking lever  28  may also act as a release lever to release tension in the device to permit its removal.  
     [0052] In operation, the first clamp  11  may be located on a suitable structure such as a gutter. Tine cable  12  may then be looped around an adjacent rail or rung of a ladder (or both) or indeed may be continued to encircle the rung or rail one or more times. The second clamp  13  may then be attached to the ladder itself, to the same structure as the first clamp  11  or to another structure which may be in the vicinity and suitable for receiving the second clamp  11 . Application of the device is easy and quick and likewise its removal is easy facilitated. Both clamps may be fixed to the same structure or alternatively to separate structures. The clamps may be fixed to the ladder with the cable configured to wrap around any suitable fixed structure that will provide adequate support. That structure may be the structure which supports the upper region of the ladder or may be another suitable structure in the near vicinity.  
     [0053] Operation of the device is seen in FIG. 2 where the second clamp  13  is clamped to a rung  29  which is supported by two spaced rails  30 ,  31 . The cable  12  is looped around a side rail  31  and the first clamp  11  is aligned for positioning to engage an outer wall  32  of the gutter  33 .  
     [0054] The first clamp  11  therefore forms first engagement means adapted to releasably engage a structure in the form of gutter  33  which is also a support structure for the upper region of the ladder. The cable  12  forms the flexible connection member which is positioned in a stabilising position adjacent the gutter  33 . Adjacent in this specification includes a position which is in working proximity to the structure and may be any suitable operative distance. The cable  12  may be wrapped around the nearest rung or rail or at another more distant position which also provides a stabilising effect.  
     [0055] Alternatively, the first clamp  11  may be attached to the ladder, the cable  12  may be wrapped around the ladder and a supporting structure with the second clamp  13  also attached to the ladder.  
     [0056] A second embodiment is seen in FIG. 3 wherein the second clamp  13  and cable  12  are substantially as described in FIG. 1. The cable  12  is located around side rail  30  and the clamp is attached to rung  29 . The first clamp  34  however is modified so that a first jaw  35  cooperates with a bracket  36  to provide a lateral support member. The lateral support member comprises a plate member  37 , tongue  38  and jaw  35  which together cooperate to provide a u shaped recess for location of the rail  30  thereby minimising the tendency for lateral displacement of the ladder. The first jaw  35 , plate member  37  and tongue  38  may be formed integrally. Alternatively as shown in the present view some of the components may be formed separately and connected in any appropriate fashion. The bracket  36  may include a channel (not shown) location over a lip  39  of the gutter  33 . The ladder rail  30  is shown in part section to better visualise the bracket  36 . The gutter  33  is fixed under the overhang of roof  100 . An additional rung  129  is also shown and highlights the versatility of the ladder stabilising device which can be located at any convenient position along the length of the ladder and not necessarily only restricted to the top end of the ladder. In some circumstances, the ladder stabilising device may be located centrally or thereabouts on the ladder. The ladder stabilising device may be stored by attachment to the ladder itself, conveniently on a low rung or around a rail so it is always to hand when required.  
     [0057] A further advantage of the adjustable clamp  13  is that it is positioned adjacent the ladder rail  30  and substantially parallel to it. This ensures that the chance of a user tripping or stumbling on the clamp  13  is minimised.  
     [0058] The bracket  36  has a threaded shaft and finger operated flange  102  for tensioning the clamping jaws of the device.  
     [0059]FIG. 4 shows a front view of the arrangement of FIG. 3 which highlights a sliding capacity formed by slot  40  in the bracket  36  which allows differential movement of the tongue  38  and first jaw  35  to thereby conform the gap provided in the bracket more closely to the width of the rail  30 .  
     [0060]FIG. 5 shows a further embodiment of the ladder stabilising device in which the second engagement means is a plate  41  permanently fixed to a u shaped rail  42  of a ladder. A strap like connection member  43  is connected to a first clamp  44  comprising opposed jaws  45 ,  46  having a first screw threaded tensioning bolt  47  and a looking means actuated by a lever handle  48  which is rotatable into contact or near contact with the first opposed jaw  45  to lock the device in place. The first clamp  44  includes an adjustable wire bracket  49  which together with the lever  48  and jaw  45  forms a lateral support member. The adjustable wire bracket  49  is slidingly engaged in a bore (not shown) in the first clamp  44  and may be locked in position by rotation of the threaded bolt  47 . The first clamp  44  is shown in locking engagement with gutter  50 .  
     [0061]FIG. 6 shows yet a further embodiment of a ladder stabilising device  14  of the present invention comprising a first clamp  11 , a strap  51  and second engagement means in the form of slide member  52 . The slide member  52  has paired runners  53  located on a bottom surface of the slide member  52  and adapted to engage and slide along corresponding rails  54  located on an outer wall  55  of a side rail  56  of the ladder  57 . The slide member  52  can therefore slide up and down the rails  54  until located in a suitable position at which stage the looking means in the form of wing nut screw  58  may be operated to lock the slide member  52  in position relative to the side rail  56 .  
     [0062] The slide member  52  also includes a length adjustment device in the form of a tensioned retraction mechanism located under housing  59 . A suitable mechanism may be similar to those used in inertia reel seat belts which provide the ability to lengthen the strap  61  and use a rotatable cam to lock the device when subject to a sudden force. The present embodiment also includes release tabs  60  which may be depressed to release the retraction mechanism and thereby retract the strap  51 .  
     [0063] The ladder stabilising device also includes a further length adjustment device in the form of buckle  61  which may be used to shorten the length of the strap  51 . This embodiment further includes a tensioning means in the form of ratchet and lever rotating drum assembly  62  explained below in relation to FIG. 8.  
     [0064] The connection member may be formed as a single belt or cord. Alternatively a plurality of parallel or even crossed elongate members may be used to form the connection member.  
     [0065]FIG. 7 is a cross sectional view of the side rail  56  of ladder  57  showing the rails  54  formed as raised runners with slots to engage the paired runners  53  of the slide member  52 . Other arrangements may be utilised.  
     [0066]FIG. 8 shows a perspective view of the ratchet and lever assembly  62  formed by a base  63 , a drum  64 , ratchet mechanism  65  and lever  66 . In use the lever  66  is pumped to rotate the drum  64  which is maintained in position by the ratchet mechanism  65 . Once suitable tension is obtained the lever  66  may be pushed into apposition with the base  63  to lock the device. The device also includes a release mechanism (not shown) to allow lengthening of the strap  51  for removal or subsequent use.  
     [0067]FIG. 9 shows a further embodiment of a ladder stabilising device  510  comprising an L shaped slot member  67  formed by a first L shaped plate member  68  and second L shaped plate member  69  spaced by an intermediate wall  70 . The L shaped slide member has an internal channel  71  dimensioned to located around the side rail  72  of a ladder  73 . A cable or strap  12  is attached to the slide member  67  at ledge  74  and is fixed at its other end to first clamp  11 . The L shaped slide member  67  is formed to avoid a rung  75  in operation and may be slid into position where it is locked by operation of the lock screw  76 .  
     [0068]FIG. 10 shows a top view of a variation of the slide member of FIG. 9. This slide member  77  is also L shaped but has a housing  78  containing a retraction device (not shown) to tension the strap  79  and also to withdraw the strap into a storage position. Release tabs  80  are also visible which may be depressed to release the strap  79  for retraction or lengthening. A side view of the device of FIG. 10 is seen in FIG. 11 with the strap  79  protruding from housing  78  all supported on the slide member  77 .  
     [0069]FIG. 12 shows a variation on the slide member principle. The ladder stabilising device  610  is shown comprising a sleeve member  81  having a slot  82  dimensioned to clear rungs  83  of a ladder  84 . The sleeve member  81  covers a substantial proportion of the side rail  85  of the ladder  84 . The sleeve member  81  also has a housing  86  with a retraction mechanism for the belt  87  which is attached to the first clamp  11 . The sleeve member  81  may be slid into position on the side rail  85  and locked in position by activation of locking screw  88 . This version of the sleeve member may also be used on a u shaped rail  89 . However, its position may also be locked by activation of second lock screw  90 . The sleeve member  81  has an additional advantage in adjustment slots  91  which permit adjustment of the width of the sleeve member to better conform to the dimensions of a rail with which it is engaged. The slot locking screws  92  may be released and two halves of the sleeve member  81  slid towards or away from each other prior to retightening of the slot locking screws in the new chosen dimension.  
     [0070] In an alternative embodiment (not shown), the first and second clamping members may be formed as slide members to each engage a separate rail of the ladder. The two members may be formed by a rigid or semi-rigid connection member. Each slide member may include a u or v shaped recess to locate over the outer wall or a roll of a gutter. The recess may be padded.  
     [0071]FIG. 13 shows a ladder  93  in position adjacent a light pole  94  and resting on an arm  96  of the pole  94 . A ladder stabilising device  96  is shown in operative position located around the pole  94  and locked to the ladder  93  and also providing lateral stability against sliding displacement of the ladder.  
     [0072] The advantages of the present invention are readily apparent. It may be formed as a relatively light weight device which can be easily carried by a person climbing a ladder. The device may be quickly and effectively located to fix and stabilise the upper section of the ladder. The point of stabilisation may be adjacent an end of the ladder or indeed may be a position intermediate the ends but which is conveniently close to a structure suitable for accepting the locking mechanisms of the device. The adjustment capacity described in the preferred embodiments allows great versatility providing the ability to loop around a rail or a rung or both prior to fixing to a suitable support structure. A further utility is provided in that the ladder stabilising device may be fixed to the ladder when it is not in operation so that it is permanently available to the user of the ladder while providing the option to be left in place in circumstances when it is not required. The ladder stabilising device may be expected to be relatively cheaply produced and readily available for use both in domestic and industrial situations. Its use may resist and some circumstances negate risk of ladder instability during use. It is preferred that the ladder stabilising device be formed from strong and weather resistant materials. It is envisaged also that seat belt material may be particularly suitable for use in this device. The range of embodiments provides the ability for fitting of the device to existing ladders. New ladders may be formed with the rails necessary for the embodiment of FIG. 6 formed integrally as part of the extrusion of the side rail material.  
     [0073] Throughout the specification the aim has been to describe the preferred embodiments of the invention without limiting the invention to any one embodiment or specific collection of features. Those of skill in the art will therefore appreciate that, in light of the instant disclosure, various modifications and changes can be made in the particular embodiments exemplified without departing from the scope of the present invention. All such modifications and changes are intended to bs included within the scope of the disclosure.