GB2508116A - A ladder for attachment to a vehicle load platform - Google Patents

Abstract

A ladder unit 11, particularly intended for attachment to a load platform (2, figure 1) of a vehicle, comprises a ladder 40 having a pair of spaced apart side members 52 and a plurality of rungs extending therebetween, and a ladder mount 41, the ladder mount including a bracket 42 attachable to the load platform, a pair of spaced apart ladder supports 46 each pivotally mounted on the ladder mount and configured to receive a side member such that the side member may slide in the ladder support, and securing means 50 to secure the ladder in a fixed position with respect to the ladder mount. The securing means may comprise a locking bolt which engages with a bracket mounted on the ladder. A fall prevention system for guarding at least one side of the load platform may also be provided.

Description

FALL PREVENTION SYSTEM AN!) ACCESS LADDER

Field of the Invention

The present invention relates to a fall prevention system and an access ladder in particular to a fall prevention system and access ladder for vehicles such as commerciaJ vehicles.

Background of the Tavention

Vehicles are used to rtatssporr goods from place to place. The load carrying platforms of commercial vehicles in particular arc positioned at such s height that if an operaior working on thc plarfonn. wcre ro fall off, he may weld be injured, perhaps seriously. It has therefore been identified that vehicles should either be able to he loaded and unloaded without an operator being required to climb onto the load carrying platforms of such vehicles or walk on and offrhc platform from/to a surince lying at substantially the same level as risc load carrying platform.

Where it is economic to do so, this is what happens. For exanaple, curtain sided vehicks are generally loaded in pa.llcdscd form, from the ground using forklift tmeks Flatbed trucks are often load at factories in loading hays! the surfaces of which lie substantially at the same level as that of the flat bed of the truck.

Floxvcvcr, there are drcum:stances where it ia not practical to load and unload gooda hi a palletised form or to provide a loading bay. Elongate objects, such as pipes are a good example.

As a rule they are often too large in both dimension and weight to paUetise, and hence are rpically loaded onto a vehicle where they are held in place by upstanding posts by nimns.of a crane which may lift the pipes over the top of the posts (or alternatively the posts may he removed during loading).

In such a scenario, an operator would usually climb onto the working platform of the vehicle to position the pipes as they are lowered by the crane. Working in such conditions presesits a danger to the operator. He may losc his footing, or be pushed by a swinging pipe tour he is attempting to control, ot simply mis-judge his position with respect to the edge of the trailer, any of which could result in a ll.

It is often the case that goods are delivered to locations vhere the construction of docking bays for loading/mlioathng is simply not economically feasible.

It is evident that operators will continue to need to Work at height, ic. on the working platform. Hence, thete is a need for a fall prevention system.

Attempts have been made to provide vehicles with fall preveorion systems. Once such system comprises a set of inflatable mattresses deployed around the velucle, their purpose being to cushion the fall of an operator from the vehicle. These Systems are thor consuming to deploy and put away and do riot actuaUy prevent a fall. The operator may still be injured in the event of a fall.

Another system comprises portable staging which is brought to a sire to provide a temporary docking facili' so that the operator may walk on and off rhe vehicle at a substantially similar level. However, such portable staging must he brought to a site, occupies space at the site, and adds to the logistical demands presented by the transportauon of goods, and in many cases cannot be justified economecally unless a significant number of deliveries are ro he made.

Another system compdses a lanyard attached at one end to the vehicle and tile other to the operator. Typically, the lanyard is attached to an inertia reel ao that the operator may move about, drawing the lanyard off the reel, but if he were to begin to fall the increase in acceleration would cause the inertia reel to prevent the further release of the lanyard. Whilst such a system offers an operator a level of protection from SUing, it would nor prevent falls in all circumstances. This will depend on the operator's position on the vehicle relative to the attachment point of the inertia reel to the vehicle. On curtain sided vehicles a mono-rail is provided along each edge of the vehicle to overcome the afore.-me.ntioaed problem, but this would not work with a flntbed trailer.

Another system for preventing falls involves attaching balusrrade to the sides of the vehide, so that if an operator on the vehicle were to fall, he would he caught lw the balustrade and prevented from falling.

One 5 stem which claims to overcome the problems associated with the aforementioned systems is described in the patent application published under number WO 2005/117065. This patent application describes a combination of a mad bed and a platform for a trailer. The platform is nioveahle between stowed and deployed positions. in the stowed position the platform is situated beneath the trailer bed, and in the deployed posnion the platlann extends alongside the trailer bed, thereby providing a walk way. A balustrade is provided along the outside edge of the platform.

Whilst the system described in WO200S/ll7otis may he regarded as an advance on the prior art, it does present its own problems. First, iris heavy, Commercial vehicles have a maximum laden weight. Every additional unit of weight taken op by the vehicle is a unir of weight that cannot he added as payload. Since haulage operators tend to chargu for their services according to the weight of goods that they carry, reducing the carrying capacity of a vehicle would make using such a vehicle undesirable, Also, comnierdal vehicles work in harsh environments where they are often hit cithcr by the payload rhat is being loaded or oultaded or by the vehicle that is dohig nor unloading, or simply by the driver of the vehicle mis-judging the position of an obecr and crashing into it, or forgetting that the platform is in the deployed condition and therefore hitting an objecr that had been missed when the platform was stowed, In the event that the platform is damaged when deployed it may not be possible to return the platform to its stowed position. The likely result of this is that the vehicle would not he able to travel on the public highway because it would be over the width permitted by law. .A fitter would have to be sent so repair the system.

Whilst commercial vehicles present a risk of falling from a height, there are other situations also presenting a risk of falling from height. For exan-rple some large machine tools have a bed that is raised above rhe grotind, arid which workers must gain a ccess to. Also, certain categories of plant include a platform which workers must gain access to and which is raised a significant height above ground level.

It would therefore be desirable to provide an improved fall preve nhiou system. The present invention seeks to provide such an improved fall prevention system that removes or at least alleviates some of the problems identified above. Such a system would have appllearion in the field of vehicles and other areas where a raised platforms are uaed and access to the platform is needed, Another problem associated with access to vehicles, in particular commercial vehicles is the provision of a means of access to the working platform from ground level. Sometimes an operator will hau.l himself up on to the platform without aid, or he may climb up one of the wheels., or a ladder may be provided. The present inventinu concerns the provision of ladders.

Where ladders arc provided with vehiele.s it is often the case that they are nor physically attached to the vehicle. This gives rise to a number rat' results: First, the operator must retrieve the ladder from its stowed position, usually a locker of some description, and pcssitioti it with respect to the vehicle, which may eithet be a position that the operator perceives as being suitable or a position designated by the designer of the vehicle. This takes time, The time taken to load, unload and haul loads is one determining factor in the ecnnoradc viability of haulage operations.

Hence, anything which increases loading and unloading times is detrimental to business of a haulage operator. Second, the ladder may easily be forgotten hy the operator or removed by a passer by. When a driver arrivea at another job, he may find the ladder missing, preventing or delaying hint in loading/unloading.

Another problem assueiated with the ladders described above is that health and safety guidance calls for such ladders tu be "footed", meaning that whilst one person climbs up or down the ladder, another is holding the foot nf'thc ladder in place. Such guidance is not necessarily limited to commercial vehicles and may apply to other situations where ladders ate used, This additional personnel reuirernent adds costs to haulage operations or other activity where the platform is not part of a vehicle or if the second person is not present porenually puts the person climbing the ladder at risk.

Some vehicles are provided with a fixed ladder extending substantially vertically. When a vehicle is loaded the height of the plarforrn above the wheels and hence the ground supporting the wheels is reduced For every day commercial vehicle operations this is not such a concern since the relative. distance moved is not great. 1-lowever, in special operations, such as the transport of crane ballast weights, the vehicle payloads are so great that the platform may fall through 300mm during loading. A fixed ladder may engage the ground and buckle, or be positioned such thar it is in danger of hitting objects that it wouid otherwtie have missed, It would therefore be desirable to provide an improved ladder, in particular for accessing plnrforms and i0 particular platforms of commercial vehicles.

Summary of the Invention

According to a first aspect of the invention there is provided a fall restraint system comprising a first member and a second member, an elongate flexible element and a tensioner for tensioning the said elongate flexible element, wherein the said clement extends hetweco the first and second members and wherein at least one of the first and second members provides en elongate flexible element support, said element engaging the support.

The first and second members may eompnse posts which may be located in hraekers, and arc preferably remocably mounted in said hrackets.

Preferably, the support is a pulley wheel.

Iris preferred that the elongate flexible element extends hack and forrh between the first and second members. In order to facilitate this, supports are attached to the first and second members at a number of selected positions.

S

Advantageously, the pulley wheels are mounted in brackets which may be removably atmchahle to the fitst and/or second members. Preferably, the brackets include an open end and extend beyond the edge of the pulley wheel.

none embodiment of the invention, the bracket includes a return which passes over the surface of the pulley wheel that is configured to support the elongate flexible element.

Depending on the distance between the first and second members it mae be desirable to provide additional members thereherween, those members mounting at least one support with which the elongate flexible elements may engage. Such members may he in the form of posts and may be removably mounted in brackets, Advantageously, the elongate flexible element is attached to a reel. This faejhtates winding in and out of the elongate flexible element. The reel may form parr of a winch. The winch or a part thereof may form the tensioner, The reel may be mounted on one of the first and second members. Preferably, the member mounting the reel indudes a plurality of supports oriented such that when the elongate flexible element passes over the supports it is caused to change direction. In one embodiment, the elongate flexible element passes over two supports each causing the said element to change direction through approximately 90 degrees, The elongate flexible element [nay be rope, for example wire rope, or a wire.

The free end of the elongate flexible element is advantageously provided with an attachment means, such as a hook or a clip. Preferably, nile of the first and second members is p.i-ovided with a corresponding attachment means, such as a bracket or an eyelet to which the attachment means of the elongate flexible element may attach.

The fall restraint system may also include a pole which may be used by an operator to deploy or stow the fall restraint system from the ground. The pole is advantageously provided with a hook which in use engages with the elongate flexible clement and allows the operator to position the said element where he desires.

Where the fall restraint system is provided on a vehicle head and sail boards may also he.

provided. The head and tail boards may he formed of solid elements, such as steel bars.

Advantageously, the fall restraint system may have a deployed state and a stowed state and be moveable between the two said states. The system may include additional supports and/or atiaclurienr means to secure the elongate flexible element in a desired position, i.e. the stowed condition. Ira one embodiment a support is provided to towards the base one of the first and second members and an attachment means, such as a bracket or a honk or an eyelet is attached to the other. In the stowed condition the free end of the elongate element is attached to the attachment means and passes around the said support and is then tensioned by the tensioner.

In one particular embodiment where the fail restraint system loans part of a vehicle and it is desitable that the elongate flexible element should not he above the load carrying surface when stowed, notches may be provided to receive the elongate flexible element in parts of the vehicle that would otherwise be fouled by the said elongate flexible element.

The fall restraint system of the invention is particularly advantageous because it maybe switched between its stowed and deployed states very easily and quickly, and furthermore this may be done by rite operator from the ground using the above-mentioned pole. Further, the parts of the system are comparatively lighi in weight. Still further, much of the system can either withstand minor knocks car easily be replaced in the event of such a knock. For example, if the load carried by a crane were to engage with the elongate flexible element, there would be one of three outcomes: the element may stretch and return to its original size; stretch hut not return to its original size, in which case die clement may be wound in further on the reel nr farther tensioned; or she element may break. In the worst case scenario of a break its the element, the operator may repair the element, with a repair kit, or by fashioning a temporary repair, or lust return to base with the element broken. With the other parts of the system, a knock resultingirt something becoming bent would not as a rule prevent the vehicle from being moved on the road.

Still further any posts ananged to support the elongate flexible element between the first and second members may be removed quicidy and easily from the ground to facilitate loading and unloading.

The fall resrtaint system may be used to protect an edge of any length or any width, with the elongate flexible member passing hack and forth ar almost arty desired spacing. All that is requited is for supports (typically policy wheclsl to he suitably positioned and the elongate flexible element to be of sufficient length.

According to a second aspect of the invention there is provided a ladder unit comprising a ladder having a pair of spaced apart side members and a plurality of rungs extending rhcrebetween, and a ladder mount, the ladder naoua,t including a bracket attachable to an object, pair of spaced apart ladder supports each pivorally mounted on the ladder mount and configured to receive a side member of the ladder such thar said side member may slide in rhe ladder support, and a securing means to secure the adder in a fixed position with respect to the ladder mount.

The spaced apart ladder supports are prekrably mounted on to the ladder mount by two pairs olspaced apart levers, one pair of Levers pivotally attached to each ladder support and the ladder mount. Together the levers, the ladder support and the part of the ladder mmlnt form a parallclograan linkage.

Preferably, the ladder mount includes uprieht members, and the pairs of levers may each he attached to an upright member. The upright members may mount a locking member and a securing means. In one embodiment a locking means is mounted on one uptight member and a securing means is mounted on anotlaer upright member. Secunng the ladder in a stowed eonfigmratioo on both sides of the ladder assists in cnsuaing stability in the sto'ved configuration.

The ladder may inelrrde stops to limit the extent to which ii may slide in the ladder supports, The securing means preferably includes a locking member, which may he a bolt.

Advantageously, the bolt has a locked state and an unlocked state and in the locked slate the bolt engages with a part of the ladder and a part. of the ladder mount. The bolt is prcfbrnhly biased into the locked stat; for example by a spring. The bolt may be slidably mounted in a bolt mount between the locked and unlocked states. For example, the bolt may he slidably mounted in a barrel. The bolt mount may include a cam surface adapted to withdraw the bolt from the locked stare upon rotation of said bolt.

The securing means may include a part associated with the iaddcr configured to engage with the bracket to secure the ladder in a fixed position with respect to the ladder mount, and that part may comprise a plate so shaped and dimensional as to engage with the bracket. The bracket may include a channel configured to receive the said part, which may comprise an element arrached to the ladder) such as a plate which may be attached to one or Inure of the side members or a rung, ur one of the nmgs itselE The ladder may be an access ladder for a vehicle.

According Lou third aspect of the in.erirlon there is provided a vehicle comprising a fall restraint system according to the invention.

According to a fourth aspect of the invention there is provided a vchicle comprising at least one ladder according to the invennon.

According to another aspect of the invention there is provided a vehicle comprising a fall restrainr system according to the first aspect of the invention and at least one ladder according to the second aspect of the invention.

Brief Description of the Drawings

in the drawings, which illustrate preferred cmbodimci-its of the invention, and arc by way

of example

Figure I is a schematic representation of one end of a vehicle according to the invention; Figure 2 is a schcmanc representation of the other end of the vehicle illustrated in Figure Figure 3 is a schematic representation of a mid-section of the vehicle illustrated in Figures 1 and 2; Figure 4 is a schematic representation of a post asserrshlv of rhc vehicle illustrated in Figures 1 to 3 viewed from inside the vehicle; Figure 5 is a schematic representation of the post assembly illustrated in Figure 4 viewed from outside the vehicle; Figure 6 is a schematic representation of the pulley arrangement mounted ott the post illustrated in Figures 4 and 5; Figure 7 is a schematic representation of a ladder according to an aspect of the invention; FigureS is a schematic representation of it ladder according to another aspect of the invention; Figure 9 is a schematic representation of the foot part of the ladder illustrated in Figure 8; sod Figure lOis a schematic representation of the top pan of the ladder illustrated in Figures S and 9.

Detailed Description of the Preferred Embodiments

Referring now to Figure 1, there is shouts part of a vehicle in the form of a fiat bed I of a truck. The flat bed I could form pan of a trailer which in use would be towed by a tractor unit, or the flat bed of a rigid truck. The Has bed I comprises a surface 2 upon which goorla arc loaded the surface 2 having edge members 3, 3'. The edge members may he formed from stcel channel section. Erackets 4 are attached to edge members 3,3' by bolts, welding or other suitable fasteners. The brackets 4 mount posts 5 which are prefcrahly removably mounred in thc brackets.

A head board 7 is attached to the front end of the flat bed 1 and comprises a pair of spaced apart posts 5, each post locating in a bracket 4. Cross rnemhets 8 arc attached to tch posts 5 and to etad members 9. The head board 7 serves to prevent an operator failing from the flat bed I over die front edge 3'. In the example illustrated the whole headboard 7 may he lifted out of the brackets 4. [he head board 7 also mounts a hand rail 10, which is used by an operator to.steady himself while climbing the ladder.

Winch mount assemblies 6 comprise a pair of spaced apart posts 5, each of which loeate.s in one of a pair of brackets 4 attached to the edge members 3. The winch mount assembly mouths a plurality of pulley wheels which facilitate the arrangement of a rope 12 extending along each side of the flat bed 1. It is these ropes, together with posts S that restrain an operator from failing off the flat bed 1. One of the posts 5 u the uinch mount assembly 6 mounts a hand rail 10', A ladder II is attached to the edge 3 in the space bem'een the hand rails and 10'. The posra 5 mas' be lifted out of brackets 4 if required.

Figure 2 illustrates the rear of the flat bed 1. A tail hoard 13 compdsinga pair of spaced apart posts S joined together by cross-members 8'. Each postS locates in a bracket 4, and whilst the tail hoard 13 would typically nor be removed to facilitate loading for example, the tail hoard may of course he removed by lifting the posts S our of the brackets 4, A ladder 11 is -attached to the rear edge 3' of the flat bed 1. A hand tail 14)' is mounted on an end post assembly 14.A hand rail may also be attached to the post 5 of the tail board 13.

II

A return post assembly iSis mounted proximate the teas' end of the flat bed 1. [he return post assembly 15 comprises a pair of spaced apart posts 5, which locate in brackets 4, Two pulley wheels 16 are mounted on one of the posts 5, each puHev wheel 16 being attached to a bracket 17 vhich is itself attached to the post 5. The buckets 17 arc shaped so as to provide an upening through which a rope may be brought up to the pulley wheel 16. However, the bracket 17 extends beyond the outer edge of pulley wheel 16 so that if the nape should for sonic reason move away from the pulley wheel, the rope will nevertheless be eonstraEed by the bracket.

Figure 3 shows a mid section of the flat bed 1. As can seen from Figure 3 posts S are mounted on the side 3 of the flat bed 1. Each post rrsounts three pulley wheels 16, each pulley wheel being attached to a bracket 17 such thar the pullet wheel 16 may rotate about its own axis.

The bracket 17 is attached to the pust 5 by a suitable fastener, which in the illustrated example is a nut and bok. The use of such a fastener rather than a weld -allows brackets 17 to he replace dif they are damaged, rather than requiring the replacement of the whole post. As can be discerned from the drawings, shove the pulley wheels 16, the brackets 17 are open. This allows the cope 12 to be lifted on or off the pulleys with relative ease.

The bucket 17' which mounts the uppermost pulley wheel 16 includes a return 17" which extends over the iop of the pulley wheel 16 ard servos to prevent the inadvertent removal if rhe rope to an unsafe position. Whilat there is suffldenr space between die upper edge 5" of the post 5 to introduce the rope 12, in the event that the rope 12 Is lifted upward, the return 17" of the bracket 17' prevents introduction of the rope.

The winch post 6 assembly will now be described in greater detail with reference to Figures 4 to 6, the which post illustrated in those figures corresponding ro the winch post 6 to the tight hand side in Figure 1. The winch post 6 assembly comptises a pair of spaced apart posts 5, which locate in brackets 4 attached to an edge 3' of the flat bed 1. The posrs 5 are joined together by cross-members 20, the upper cross-member 20 mounting a pulley wheel unit 25, which comprises two pulley wheels 2R, 30 mounted on brackets 27 and 29 respectively, the bracket 27 being mounted on a member 26 which projects from and is attached to a post 5 and l2 the upper-cross member 20. The bracket 29 is mounted directly to usc underside of the upper-cross member 20. A further pulley wheel lóis mounted on a bracket 17 which is attached to one of the posts 5 nod is positioned such chat a rope coming off pulley whecl 30 is aligncd horizontally such that the rope would sit on the pulley wheel 16.

Refertingto Figure in particular, two further pulley wheels Ill are attached to one of the posts 5 of the assembly 6 by means of brackets 17. Pie brackets 17 provide open ends so that a rope may be presentcd up to the pulley wheel 16 carried by die respective bracket, The open ends provided by brackets 17 face in opposite directions. This facilitates attachment of a rope 12.

A further pulley when lóis attached to one oldie posts Sand provides for stowing of a rope 12 when the fall restraint system is trot required, or better access to the vehicle is required.

In the illustrated example this pollee wheeL and bracket are situated at about the level of the winch 22.

list winch 22 forms part of the teinch post assembly is mounted on a bracket 21 which is itself attached to one of the posts 5.

A rope 12 is attached to the winch 22, and is provided at its free end with a hook, so that the rope may he attached to an ob1eet and then pulled tight by operation the winch. In the example the winch is powered by a handle, but could equally he electrically. hydraulically, pneumatically powered for example.

The rope 12 passes from the winch 22 in a substantially vertical direction to pulley 28 over which it passes and changes direction through approximately 90 degrees, such that it lies substantially horizontal. The rope l2 then passes around the policy wheel 30 where the rope again changes direcdr,n through approximately 90 degrees. Corning off the pulley wheel 30 the rope 12 remains in a substantially horizontal plane bun extends in a direction substantially parallel with the edge 3. The rope 12 supported in this horizontal plane by the pulley wheel 16 attached to the top of the post S of the winch post assembly 6 as described above with reference to Figure in particular.

From this point, the rope 12 may then either he deployed to provide a fall restraint or stowed to allow better access to the flat bed 1.

A description of how the fall restraint system is deployed and stowed will now follow: In the stowed condition, the rope 12 extends around the pulley wheel 16 at the top of posr 5 of winch post assembly, turns through approximately 90 degrees and travels vertically downwards to pulley wheel 16 proximate the winch 22 where it again turns through approximately 9(1 degrees. As can be seen from Figure 1 this pulley wheel 16 is positioned such that the rope 12 lies just below the level of the surface 2. The rope extends along the side of the flat bed 1 substantially parallel with edge 3 and is attached to the bracket 4 supporting the return post assembly 15. The bracket 4 is provided with a hole through whic}i a clip of hook attached to the rope maybe passed. In order that the rope 12 may lie below the lcve.l of surface 2, the brackets 4 are provided with notches 4a in which the rope 12 may lic The winch 22 is wound hy handle 23 to tighten the rope 12 and the winch is then locked so that the rope remains tights and out of the way.

Ijenloyl n the Fall Restraint System If the posts 5 along the edges 3 of the flat bed I have been removed they are attached, which is simply a matter of slotting their lower ends into brackets 4 and passing a pin through the post and hracket to secure one to the othet To bring the rope 12 from the stowed condition to the deployed condition, the which 22 is unlocked so that rope 12 may be drawn off. I'he rope 12 is then unhcmoked from the return post assembly 15 and lifted off the pulley wheel 16 proximate tise winch 22. The rope 12 is then placed over the upper pulley vhccl 16 of die return post assembly 15 (see Figure 2), and turned through approximately 90 degtces to travel vertically downward to the lower pulley wheel 16 of the return post assembly. The rope 12 is passed through the opening of bracket 17 unto the pulley wheel 16 where the mpe is tensed through approximately 90 degrees such that it lies in a substantially horizontal plane. The rope 12 is brought to the upper pulley wheel 1 6a of the winch post assembly 6. The rope 12 is passed through the opening in bracket 17 and presented up to the pulley wheel 16a, around which it passes end turns through approximately 90 degrees ro travel vertically downwards to the lower pulley wheel lob of the winch post assembly 6. The rope 12 is passed through the downward facing open end of bracket 17 and presented up to pulley wheel lOb, around which it passes and turns through approximately 90 degrees 10 travel in a substantially horizontal plane hack to the return post assembly l5 where the hook or clip attached to the free end of the rope 12 is attached ro an eyelet 31 fixed to a post S of the return post assembly 15.

The rope 12 then extends horizontally along the side of the flat hod I and three verecally spaced apart locations. Deployment is completed by lifting rhe rope 12 over foe brackets 17 and allowing the rope to lowrt between the inside of the bracket 17 and the outside of the postS towards the pullewheels 16. In the case of the upper bracket 17', the rope 12 must he lifted upward, and move side ways, then downward so that it is aligned with the opening presented between the return 17" and the top of the post 5. With the rope so positioned it is pulled sideways through the said opening until the rope is aligned with the space between the inside vertical surface of the bracket 17' and the outside of post 5, whereupon the rope "lay fall vertically to lie on the pulley wheel 16.

The winch is then wound so as to tighten the rope 12 and locked off when sufficient tension in the rope 12 has been attained.

To go back to the stowed configuration, the proeedutc is reversed.

It is advantageous that the stowed condition involves the rope 12 being partially extended for two reasons. First, it means that a smaller winch barrel is required, and sccorsd, the time taken to deploy the system is reduced because the rope 12 is partially drawn off the winch 22.

In the illustrated example the vehicle is provided with two ladder unites II to allow an operator to gain access to the surface 2 of the flat bed 1.

The bdder unit 11 will now he desctibed with reference to Figures 1,2 and 7. The ladder unit 11 comprises a ladder 40 and a mount 41. The mount 41 includes a bracket 42 which provides for attachment of the ladder unit 11 to the edge 3 of the flar bed 1. The bracket 42 includes holes 44 through which bolts ace passed to facilitate the said attachment. A pair of brackets 46 ate attached to side plates 43 of the bracket 42, the htackers 46 being attachcd to the side plates 43 by pins of bolts extending through holes 45 in the side plates 443. Each bracket 46 is shaped such thatch side member of the ladder 40 may slide therein.

The ladder 40 includes a plate 47 attached to the side members of the ladder 40. A bracket 50 mounting a bolt 50 is attached to the plate 47. 1he plate 47 indudes returns 49 at each end rhcrcof to facilitate attachment of the plate to the side members 0f the ladder 40. In Figure? the ladder is shown in the stowed position, with the bolt 50 extending through the side member of the ladder 40 and into a hole 51 in the side plate 43.

The horrom edge of the plate 47 sits in a channel in the bracket 42 fisrrncd by a lip 47'.

The kip is covered with a resilient material 48, such as a piece of rubber or foam fur example, which assists in maintaining the ladder 40 In the substantially vertical orientation illustrated in Figure?, To deploy the ladder 40, the operator releases the bolt 50. then lifts the ladder upward so that the utidctside of rite plate 47 may clear the lip 47'. He then pulls the base of the ladder away from the bracket 42 so that the ladder may slide duwr.wardLy tonAl tEe feet 53 of the ladder engage with the ground. Mounting the ladder so that it may slide in brackets 46 allows any change in distance between the surface 2 and the ground (duc to the load placed on the surface 2) to bc taken up.

Referring flow to Figures 8 to 10, there is shown an alternative ladder arrangement for mounting on a platform. 1hc arraragemen.t comprises a ladder 60 comprising side members Oils with rungs 6Gb extending thereberween, and a ladder mount 61 which includes a plurality of bores Ma through which fasteners may he inserted to fasten the mount 61 to an object, such as the platfoma of a t'ehicle. The mount 61 also includes a top plate from which extend uprighL rails 62, 63. Thc top plate also provides a support for the ladder 60 in its stowed position.

The side members 60a of ladder 60 are arranged to slide in brackets 64, which are themselves attached to the upright rails 62, 63 by arms 65, which are pivotally attached to the side members OUst of the ladder 60 at pivot points 65a arid to rhe rails 62, 63 at pivot points 65b.

Upward and downward sliding of the side members dOs in the brackets 64 is limited by stops God and 60e. The side members GOa of the ladder 60, the uptight brackets 64, and tile arms 65 together form a parallelogram hnksgc The parallelogram linkage allows for the ladder 60 to move away from the ladder mount (si so that the ladder may clear that mount and he lowered to the ground.

Referring now to Figures 8 to 10, the ladder 60 is secured in the stowed Configuration shown in Pigute 8 by a locking attangement which comprises an tipper locking means element 70 disposed to the top of the ladder sod another disposed to the bottom of the ladder, and a lower locking means 75 disposed to the bottom of the ladder, The upper locking means 70 comprises a hracket 71 attached to the side member OOa of the ladder, by welding for example. The bracket 71 includes a curved portion 71 a. In the locked configuration the curved portions 71a of the bracket 71 engages with a recess 63b of a bracket 63h which is itself attached to the upright rail 63.

The lower locking means 75 at the foot of the side member (sOs of the ladder 60 comprises a bracket 76 attached to the side member 60a and a bracket 77 attached to the upright rail 62. A spring loaded pin assembly is attached to the bracket 77 and compriaca a barrel 78 having a earn surface 79. A pin 80 is arranged to both slide within rhe barrel 78 and rotate about its own axis. A handle 81 projects from the pin 80 and engages with the cam surface 79, The pin is of sufficient length to extend through a bore in the end face 76a of the bracker 76 when the pin 80 and bore are aligned, as they are in the locked configuration illustrated in Figure 9.

To deploy the ladder 60, an operator rotates the pin 80 about ie own axis b gripping the handle 81 and toning the handle and hence the pin through approximately 180 degrees. As will he appreciated from Figure 9, as the pin 80 rotates the action of the earn surface 7Pon the handle 81 causes the pin 80 to slide axially within the barrel 78. and tn disengage from the bore itt the end face 76a of the bracket 76. With the lower locking means 75 unlocked, the operator may then slide the ladder 60 in the brackets 64 upwards to disengage the upper locking means 70.

With both upper and lower locking means disengaged, the operator may then swing the brackets 64 and hence the ladder 60 ouard and downward. The arms 65 rotate about the pivot points 65a, 65b until they lie below the horizontal. The operator then slides the ladder 60 within brackets 64 until the feet 60e of the ladder 60 rest upon a surface.

To return the ladder 60 to the stowed position illustrated in Figure 8, the procedure described above is reversed.

Both the parallelogram action of the arms 65 and the sliding nature of the ladder 60 in brackets 64 allow for the differences in heighr of a load platform above ground level to be taker up. For example, it may be necessary for the operator to climb on board the platform of a vehicle before it is loaded. The ladder would therefore he deployed and the uperatcr would mount the platfrsnrj via the ladder. However, as load is placed on the platform, the suspension of the vehicle would become compressed bringing the platform closer to the ground. Hence, to avoid the ladder buckling, it must be capahle of moving with respect to the platform. The parallelogram arrangement also allows the ladder to be stowed within the perimeter 0f the platlbrni when stowed, but be brought heynnd the perimeter of the platform when deplosed.

Thc ladder 60 is relatively long. By providing locking means to both the top and bottom of the ladder, the ladder is made stable in its stowed configuration. Also, by pros-iding a locking anangement where each part of the arsangcn-senr is operable from the ground, the ladder may he moved easily between the deployed and stowed configurations.

The ladder of the invention provides a number of advantages. First, the change in distance between, the surface 2 and the ground due to loading and unloading can he taken up.

Second, the ladder is attached to the vehicle. This means that it is not necessary to have a second person footing the ladder, thereby saving labour and increase timeliness. Third, the ladder is much less likely to become separated from the vehicle than is the case where the ladder is stored loose. Fourth, the posieorL of the ladder with respect to the truck is determined by manufacturer not the operator. Therefore the ladder may be provided with hand rails for example. In rhe case of the embodiment illustrated in Figures 8 to 10, the uprights 62,63 may serve as grah rails.

Claims (11)

1. Claims 1. A ladder unit comprising a ladder having a pair of spaced apart side members and a pluSity of rungs extending therebetween, and a ladder mount, th&ladder mount including a bracket attxhnhle to an obiect a pair of spaced apart ladder supports each pivotally mounted on thc ladder mount and con6gured to receive a side member of the ladder such that said side members may slide in the ladder support, and a securing means to secure the ladder in a fixed position with respect to the ladder mount.
2. 2. A ladder unit according to Claim I, wherein the securing means includes at least one locking member.
3. 3. A ladder unit according to Claim 2, wherein a locking member includes a bolt having a locked state and an unlocked state and in the locked state the bolt engages with a part of the ladder or an element having a fixed relationship with the ladder and a part of the ladder mount.
4. 4. A ladder unit according to any of Claims I to 3, wherein the securing means includes a pan associated with the ladder configured to engage with the ladder mount to secure the ladder in a fixed position with respect to the ladder mount.
5. 5. A ladder unit according to Claim 4, wherein the said part of the securing means is so shaped and dimensional as to engage with a bracket.
6. 6. A ladder unit according to ClaimS, wherein the bracket is situated towards the top of an upright element of the ladder mount.
7. 7. A laddcr unit according to any of aam 3 in 6, wherein the bolt in the locked state engages with a bracket attached to the ladder,
8. 8. A ladder unit according to Claim 7, wherein the bolt is attached to an upright element of the ladder mount
9. 9. A ladder unit according to Claim 4 or 3, wherein the bracket includes a channel configured to receive the said part of the securing means.
10. 10. A vehicle comprising at least one ladder unit according to any of Claims I to 9.
11. 11. A vehicle comprising a fall prevention system for guarding at least one side of a platform having a plurality of sides, the system having a stowed state and a deployed state and comprising a first member and a second member, an elongate flexible element and a tensioner for tensioning the said elongate flexible element, whetS in the deployed state the said element extends between the first and second members, and wherein at least one of the first and second members provides an elongate flexible element support, said element engaging the support, and the elongate flexible element extending along and guarding a side of the platform, and wherein in the stowed state the elongate member is positioned to allow access to the side of the platform, wherein each support is mounted in a bracket and wherein each bracket is configured such that the elongate flexible element may be inserted into or removed from the bracket by moving the said elongate flexible element radially towards or away from the support mounted in the bracket, and at least one ladder unit according to any of Claims 1 to 10.

    12, A ladder unit substantially as shown in, and as described with reference to, Figures 1 to 10.