GB2553000A - A ladder system - Google Patents

Abstract

A ladder system comprising two ladder sections 10, 20 each with the same spacing between their stiles 30, 40 and 50, 60 at one end so that whenthe two sections are placed end-to-end at least one surface of one stile of one ladder section is contiguous with at least one surface of one stile of the adjacent ladder section. The ladder system includes a clamp 90 to clamp the two ladder sections together to form one continuous ladder. Multiple clamps may be included and they may be adjustable. The clamp may be an over-centre clamp and have two parts 95, 100, one attachable to each ladder section. One ladder section may include a male projection 46 at one end of one stile with the other ladder section including a female socket 61.

Description

(54) Title of the Invention: A ladder system

Abstract Title: Ladder sections clamped to form continuous ladder (57) A ladder system comprising two ladder sections 10, 20 each with the same spacing between their stiles 30, 40 and 50, 60 at one end so that whenthe two sections are placed end-to-end at least one surface of one stile of one ladder section is contiguous with at least one surface of one stile of the adjacent ladder section. The ladder system includes a clamp 90 to clamp the two ladder sections together to form one continuous ladder. Multiple clamps may be included and they may be adjustable. The clamp may be an over-centre clamp and have two parts 95, 100, one attachable to each ladder section. One ladder section may include a male projection 46 at one end of one stile with the other ladder section including a female socket 61.

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Intellectual

Property

Office

Application No. GB1614203.6

RTM

Date :6 February 2017

The following terms are registered trade marks and should be read as such wherever they occur in this document:

Antiluce

Intellectual Property Office is an operating name of the Patent Office www.gov.uk/ipo

A ladder system

The present invention relates generally to a ladder system and a method of attaching ladders together to form a longer ladder and finds particular, although not exclusive, utility in the use of such ladders for materials handling.

It is known to extend the reach of a first ladder by resting hooks, provided on a second ladder, onto a rung of the first ladder. The stiles of the second ladder are also typically slidingly connected to the first ladder through open sided brackets provided on the first ladder. This creates a step at the junction of the two ladders which is undesirable for safety reasons. It also prevents the joined ladders from being used for material handling with a trolley.

In one aspect, the invention provides a ladder system comprising two ladder sections each comprising the same spacing between their respective stiles at one end thereof such that when the two sections are placed end-to-end at least one surface of one stile of one ladder is contiguous with at least one surface of one stile of the adjacent ladder, the ladder system further comprising a clamp for clamping the two ladders together such that they form one continuous ladder.

The ladders sections may have stiles with substantially rectangular crosssections. The at least one surface may be the front surface of the stiles, the rear surface being the one parallel to the front surface and spaced apart by the sides of the stiles. The sides of the stiles are the surfaces through which the rungs pass. The inside side surfaces are the surfaces facing each other across the length of the rungs. The outside side surfaces are the surfaces facing away from the rungs.

The stiles of the two ladder sections may have the same spacing, measured from inside side surface to inside side surface.

By clamping the two ladder sections together one continuous ladder may be created which has a continuous stile surface and with the length of all rungs lying in the same plane. In this regard the at least one surface may be a portion of a stile. The term contiguous may mean lying in the same plane. The cross-section of the stiles may be “C” shape and accordingly the at least one surface may be a portion of the curved crosssection.

The clamp may be arranged to impart a compressional force onto the ends of the two ladder sections which meet. In this regard, the ladder ends may be considered to be squeezed, or post-tensioned, together.

The clamp may comprise two parts with one part being attachable to one ladder section and the other part being attachable to the other ladder section. Either or both parts may be releasably attachable to the sections. Either or both parts may be integral with the sections, in that at least some element of one of the parts is formed with the ladder.

The two parts may be attached directly to the ladder section stiles. Alternatively, the two parts may be attached to the ladder section stiles via haunches which space the two parts distally from the stiles. The use of haunches may reduce the loss of structural integrity of the stiles which may result if attaching the two parts directly to the stiles. They may also increase the effective depth and efficiency of the connection.

One or more of the haunches may straddle the joint interface between stile ends, or both haunches may terminate at the joint interface.

The two parts may be attached by any one or more of welds, bolts, screws, rivets, pins, and grip fasteners. Slotted fasteners may be employed having male and female releasably connecting members. Other means, for example straps or tensioned strands are also contemplated.

The two ladder sections may have lengths in the range of 0.75 to 5 metres.

The ladder system may further comprise a rigid member releasably attachable to at least one ladder section and extendable across the joint formed between the two ladder sections such that the stiffness of the joint is increased. For instance a rigid bar may be pivotably attached to the rung or stile near the end of one ladder section. It may be releasably attachable to a rung or stile of the adjacent ladder section such as by means of a hook, clamp, bolts, or slots. A deviator assembly may be incorporated at or near the joint interface to increase the effective depth and efficiency of the tensioning device. The rigid member may comprise a side plate located on the outside stile surfaces.

One ladder section may comprise a male projection at the end of one stile and one other ladder section may comprise a female socket arranged at the end of one stile.

The ladder system may further comprise a female socket at the end of each stile at one end of one section, and a corresponding male projection at the end of each stile at one end of another section.

The male/female projections/sockets may aid alignment of the ladders during assembly of the sections. They may also convey shear forces across the joint interface. They may also act to increase the stiffness of the joint between the two adjacent ladder sections.

The ladder system may comprise only one clamp on each stile. However, it may comprise one or more additional clamps for clamping the two ladders together such that they form one continuous ladder. The one or more additional clamps may be attachable directly or indirectly to the stiles. They may be attachable to different surfaces of the stiles such that the at least two or more clamps are attachable to the front and rear surfaces, or one of the front and rear surfaces and one of the side surfaces. It is possible to have clamps attached to all four surfaces on each stile.

At least one of the haunches may include a compressible pad between the adjacent haunches to transfer the compressive force imparted by the clamp, in use, from the clamp into the stile.

Instead of a pad, a gap may be provided. The pad or gap may ensure the compressive force provided by the clamp in use acts eccentrically to pre-load the main ladder joint. The gap may be constant between the stile ends or may taper such that the stile ends are in contact at one end (e.g. the rear face of the stile) but are distal from one another at the other end (e.g. the front face of the stile).

Each haunch may include a compressive pad such that there are two pads adjacent one another.

The haunches are expected to be arranged on the front or rear surfaces of the stiles but it is also possible to arrange them on the side surfaces as well.

An attachment means may be provided to releasably attach the two haunches together in addition to the clamp. For instance, a nut and bolt or an antiluce fastener may be employed as a fail-safe connection. Further fasteners may be provided through the sides of the haunches and through the sides of the ladder stiles to further reinforce the connection.

The haunches may be attached to the ladder stiles by any one or more of welds, bolts, screws, rivets and pins, or slotted rebates, projections or ribs.

The clamp may be an over-centre clamp and may be adjustable to select the compressive force imparted. Other types of clamp are contemplated such as G clamps, ratchet straps, pipe clamps, bar clamps, spring clamps, C clamps, and runway clamps.

Wire tensioning devices such as Highfield levers, rigging screws or wires tensioned by pivoting or telescopic mast assemblies are also contemplated. Threaded bars which extend from one ladder section another and which may be tensioned, for instance by a nut are also contemplated.

The ladder system may further comprise a materials handling or personnel trolley for running along the stiles of the one continuous ladder.

The above and other characteristics, features and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention. This description is given for the sake of example only, without limiting the scope of the invention. The reference figures quoted below refer to the attached drawings.

Figure 1 is a perspective view of two ladder sections including clamps unconnected;

Figure 2 is a perspective view of the ladder sections of Figure 1 connected and partially clamped;

Figures 3 and 4 are side views of two ladder sections clamped together using different clamps.

The present invention will be described with respect to certain drawings but the invention is not limited thereto but only by the claims. The drawings described are only schematic and are non-limiting. Each drawing may not include all of the features of the invention and therefore should not necessarily be considered to be an embodiment of the invention. In the drawings, the size of some of the elements may be exaggerated and not drawn to scale for illustrative purposes. The dimensions and the relative dimensions do not correspond to actual reductions to practice of the invention.

Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequence, either temporally, spatially, in ranking or in any other manner. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that operation is capable in other sequences than described or illustrated herein.

Moreover, the terms top, bottom, over, under and the like in the description and the claims are used for descriptive purposes and not necessarily for describing relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that operation is capable in other orientations than described or illustrated herein.

It is to be noticed that the term “comprising”, used in the claims, should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It is thus to be interpreted as specifying the presence of the stated features, integers, steps or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or components, or groups thereof. Thus, the scope of the expression “a device comprising means A and B” should not be limited to devices consisting only of components A and B. It means that with respect to the present invention, the only relevant components of the device are A and B.

Reference throughout this specification to “an embodiment” or “an aspect” means that a particular feature, structure or characteristic described in connection with the embodiment or aspect is included in at least one embodiment or aspect of the present invention. Thus, appearances of the phrases “in one embodiment”, “in an embodiment”, or “in an aspect” in various places throughout this specification are not necessarily all referring to the same embodiment or aspect, hut may refer to different embodiments or aspects. Furthermore, the particular features, structures or characteristics of any described example, embodiment or aspect of the invention may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more other examples, embodiments or aspects.

Similarly, it should be appreciated that in the description various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Moreover, the description of any individual drawing or aspect should not necessarily be considered to be an embodiment of the invention. Rather, as the following claims reflect, inventive aspects lie in fewer than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this invention.

Furthermore, while some embodiments described herein include some features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form yet further embodiments, as will be understood by those skilled in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination.

In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practised without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

In the discussion of the invention, unless stated to the contrary, the disclosure of alternative values for the upper or lower limit of the permitted range of a parameter, coupled with an indication that one of said values is more highly preferred than the other, is to be construed as an implied statement that each intermediate value of said parameter, lying between the more preferred and the less preferred of said alternatives, is itself preferred to said less preferred value and also to each value lying between said less preferred value and said intermediate value.

The use of the term “at least one” may mean only one in certain circumstances.

The principles of the invention will now be described by a detailed description of at least one drawing relating to exemplary features of the invention. It is clear that other arrangements can be configured according to the knowledge of persons skilled in the art without departing from the underlying concept or technical teaching of the invention, the invention being limited only by the terms of the appended claims.

In Figure 1 a ladder section 10 and a ladder section 20 are shown being offered up to one another for connection thereof. The ladder section 10 comprises two stiles 30, 40 connected together by rungs 13. The ladder section 10 comprises a hollow aluminium box section. The rungs 13 are also hollow and connect through the box section projecting therethrough such that the hollow interior 14 of a rung 13 is partially visible.

The other ladder section 20 has the same features as described above with regard to first ladder section 10.

At the end 35, 45 of each of the stiles of the first ladder section 10 projecting male members 36, 46 are arranged. These are substantially cuboid such that they have four flat sides parallel to the four sides of the box sectional stiles. However, they are slightly smaller in width and height such that they fit inside the hollow box sections of the corresponding stiles 50, 60 in the second ladder section 20. In this regard, the ends 51, 61 of the stiles 50, 60 are open and may be considered as female sockets.

The male members 36, 46 may comprise aluminium and may be hollow; however, other materials are contemplated such as steel, carbon fibre and timber. They may be solid or hollow.

The male members and female sockets aid the location of the ladder sections 10, 20 together such that the clamps 70, 90 may be engaged. The socket connection may also convey shear forces across the joint interface, with the clamps accommodating bending forces (moments).

The male member 36 is shown with a “V” shape slot 37 on its outer end. Such a cut-out feature may be used if there is a rung 23 which would impede its passage into the female socket. Although this would not be the case in the example shown in Figure 1 the principle is correct.

Turning now to the clamps, there are two shown. A first clamp 70 is shown having two parts 80, 85 one on each corresponding stile 30, 50 of the ladder sections 10, 20, and a second clamp 90 having two parts 95, 100 one on each of the other two corresponding stiles 40, 60.

With regard to the first clamp 70, the first part 80 comprises a haunch which has two sidewalls 71 pivotably connected to the stile 50 by a pin 78 such that they may lie adjacent the side of the stiles and rotate up and away therefrom. The two sidewalls 71 are joined together by a plate 68 which lies perpendicularly thereto and which lies approximately parallel to, but spaced from, the front surface of the stile 50 with the clamp in the clamping position, as shown in Figure 1. The two sidewalls 71 may be arranged to be very close to the sides of the stile to prevent bending of the clamp part 80.

The clamp body 64 is attached to the top of the plate 68. The body 64 comprises a saddle in which a handle 72 is pivoted by a pin 73. An arm 74 is pivoted to the handle at a different location from the pin 73. On the end of the arm 74 is a threaded bar 75 which may be wound in and out relative to the arm 74. At the distal end of the threaded bar 75 is a catch 76 including a hook portion 77.

A meeting face 67 is arranged perpendicular to the top plate 68 and the sidewalls 71 such that it is parallel to the plane of the open hollow female socket with the clamp part 80 in the clamping position, as shown in Figure 1.

The second part 85 of the clamp 70 also includes sidewalls 86 which have the same relationship to the stile 30 sides as the sidewalls 71 being pivoted thereto by pin 87. The close proximity of the clamp and haunch sidewalls minimises load eccentricities '(and associated bending effects) in the pin 87. A top plate 88 is also provided in a similar manner to the top plate 68. On the top of the top plate 88 a receiving portion 89 for receiving the hook 77 is arranged.

A meeting face 66 is arranged perpendicular to the top plate 88 and the sidewalls 86 such that it is parallel to the plane of the open hollow female socket with the clamp part 85 in the clamping position, as shown in Figure 1.

The clamp 70 may be arranged on other surfaces of the stiles such as the rear, inside and outside side surfaces.

The second clamp 90 also includes a first part 95 and second part 100. The first part 95 is attached to the other of the stiles 40 of the first ladder section 10 and the second part is attached to the other of the stiles 60 of the second ladder section 20.

The first part 95 includes a body 91 being a saddle in which a handle 92 is pivoted by pin 93. An arm 94 is pivoted to the handle 92 at a different location from the pin 93. On the end of the arm 94 is a threaded bar 95 which may be wound in and out relative to the arm 94. At the distal end of the threaded bar 95 is a catch 96 including a hook portion 97.

The second part 100 of the clamp 90 is a simple plate including a curved hook receiving portion 102.

The first part 95 is arranged on the outer side surface of the stile 40 and the second part 10 is arranged on the outer side surface of the stile 60.

The clamp 90 may be arranged on other surfaces of the stiles such as the front, rear and inside side surfaces.

In Figure 2 the two ladder sections 10, 20 are shown pushed together with the male projections inside the female sockets and the ends of the two ladder sections adjacent one another. The side surfaces of each respective pair of stiles 40, 50 are shown contiguous with one another such that they both lie in the same plane. This is also true for each pair of rear and front surfaces.

The second clamp 90 is shown with the hook 96 engaged on the hook receiving portion 102. To achieve this, the arm 94 and threaded bar 95 have been rotated relative to the handle and body 91 such that their longitudinal axis is substantially parallel to the side surface of the stiles 40, 50.

The handle 92 may now be rotated relative to pin 93 such that it tensions the arm 94 and threaded bar 95. In an ideal state the length of the handle 92 will lie adjacent the stile 40. To achieve this the distance of the hook 97 from the body 91 may be adjusted by winding it in or out as required.

Although, not shown, the first clamp 70 may be closed in a similar manner with the hook 77 engaging the hook receiving portion 89 and the handle 72 lying close to the stile.

To connect two ladder sections it is contemplated that such clamps will be arranged one on each pair of corresponding stiles. However, it also contemplated that in some circumstances it may be desirable to have more than one clamp on each stile such that the ladder sections may include one on each of the four surfaces of the stiles. Clamps arranged on only two (as shown in Figure 2) or three surfaces are also contemplated.

In Figure 3, a different clamp 200 is shown. It is similar to the first clamp 70 shown in Figure 1 in that it includes sidewalls 271, 286 which sandwich each respective stile 230, 250. It is also arranged on the front surface of the stiles. The sidewalls 271, 286 are shown pivotably connected to the stiles by pins 278, 287 arranged at the end of the sidewalls distal from the meeting point of the two stiles.

Other ways of attaching the sidewalls to the stiles are contemplated such as by welding and/or bolting, and/or slotted inserts. The two haunches may not be rotatably connected to the stiles.

The top plates 270, 280 lie adjacent and parallel to the front face of the stiles but substantially close to this front surface, unlike the one shown in Figure 1. The two parts of the clamp are attached to this top plate by welding, although other means of connection are contemplated such as bolts, pins or slotted inserts.

The clamp comprises similar features as described above with regard to the first clamp 70 in that it has a body 264, a handle 272 pivotably connected thereto via a pin 273, a hook portion 277 and a hook receiving portion 289.

The clamp 200 is shown in the closed, active, clamping position.

The male projection 36 is shown extending into the female socket 236 on the left hand stile 250. It is also shown extending inside the right hand stile 230. It may be fixed inside the right hand stile 230 by means of bolts, pins or welding and the like. Alternatively it may be formed integrally with the stile 230 or retained by pins through the stiles, or loosely held in place by end-stops inside the ladder stiles, or by contact against ladder rungs.

In Figure 4, a different clamp 300 is shown. In this version the top plates 370, 380 are spaced distally from the front surface of the stiles 330, 350 by sidewalls 371, 386. However, in this version the side walls do not sandwich the stiles 330, 350. Instead they predominantly stay above the stiles. They are attached to the stiles by stilehooks 374, 384 each arranged at one end of the sidewalls 371, 386 distal from the point at which the ladder sections meet. The hook portions 374, 384 hook over respective pins 378, 387 which project from the stile side surfaces.

Each clamp part may include two sidewalls parallel to each other each including a stile-hook such that they engage pins arranged on both opposing side surfaces of each stile. The engagement may also be arranged to attach to a projection arranged on the front or rear surface of the stile. The top plates may also be inclined relative to the front face of the stiles, subject to compatibility with the clamp fastener details.

The stile-hooks are shown open such that they can be easily disengaged from the pins with the clamp unlocked. This allows for removal of the clamp parts when not required.

The top plates 370, 380 lie adjacent and parallel to the front face of the stiles. The two parts of the clamp are attached to this top plate by bolts 311, although other means of connection are contemplated such as by welding or slotted inserts.

The clamp comprises similar features as described above with regard to the first clamp 70 in that it has a body 364, a handle 372 pivotably connected thereto via a pin 373, a hook portion 377 and a hook receiving portion 389.

The clamp 300 is shown in the closed, active, clamping position.

The male projection 36 is shown extending into the female socket 336 on the left hand stile 350. It is also shown extending inside the right hand stile 330. It may be fixed inside the right hand stile 330 by means of bolts or welding and the like. Alternatively it may be formed integrally with the stile 330, or loosely secured in place with end-stops.

The two parts of the clamp 300 also each include a meeting face 322 which are plates which lie perpendicularly to the planes of the top plates 370, 380 and extend between the top plates 370, 380 and the base of the sidewalls 371, 386. In this way, with the clamp closed and in the clamping position, the meeting faces extend to, or towards, the front face of the stiles.

The meeting face and haunches may be centred symmetrically about the joint interface. Alternatively, the haunches may be unsymmetrically disposed to straddle the ladder joint. The haunch sidewalls may further extend over the ladder stiles to straddle (and thereby reinforce) the joint in the stiles, possibly including further (sidewall) clamps.

The meeting faces may include a hole passing therethrough with them in this adjacent position. A bolt 309 or other means such as an antiluce may be used to attach the two together. This may be considered a fail-safe in case the clamp fails.

A compressible pad may be arranged on the outer face of each, or both, meeting face. Alternatively, the outer faces may be recessed from one another to provide a gap therebetween. The arrangement of the meeting faces affects the distribution of prestress in the joint elements and ladder stiles. The exact joint configuration may be designed according to the relative composition of the joint members and stiles.

The meeting face of the stiles within the ladder joints may be profiled (or cut accurately square) to ensure good contact across the plates forming the front (top) surface of the stiles for the transfer of compressive forces across the joint interface. The meeting face may further include supplemental strengthening plates, or an increase in member thicknesses at or near the front surface to limit compressive (contact) stresses across the joint interface.

The clamp may also comprise only a single saddle shape part which is arranged to straddle the joint interface. Oval shape holes may be provided through the saddle aligned with holes provided in the stiles. In use oval shape pins could be passed through the holes and turned through 90 degrees to urge the two ladder sections together. Shapes other than oval are also possible.

Claims (18)

1. A ladder system comprising two ladder sections each comprising the same spacing between their respective stiles at one end thereof such that when the two sections are placed end-to-end at least one surface of one stile of one ladder is contiguous with at least one surface of one stile of the adjacent ladder, the ladder system further comprising a clamp for clamping the two ladders together such that they form one continuous ladder.

2. The ladder system of claim 1, wherein the clamp is arranged to impart a compressional force onto the ends of the two ladder sections which meet.

3. The ladder system of either one of claims 1 and 2, wherein the clamp comprises two parts and one part is attachable to one ladder section and the other part is attachable to the other ladder section.

4. The ladder system of claim 3, wherein the two parts are attachable directly to the ladder section stiles.

5. The ladder system of claim 3, wherein the two parts are attachable to the ladder section stiles via haunches which space the two parts distally from the stiles.

6. The ladder system either one of claims 4 and 5, wherein the two parts are attachable by any one or more of welds, bolts, screws, rivets, pins, slotted rebates and grip fasteners.

7. The ladder system of any preceding claim, wherein the two ladder sections have lengths in the range of 0.75 to 5 metres.

8. The ladder system of any preceding claim, further comprising a rigid member releasably attachable to at least one ladder section and extendable across the joint formed between the two ladder sections such that the stiffness of the joint is increased.

9. The ladder system of any preceding claim, wherein one ladder section comprises a male projection at the end of one stile and one other ladder section comprises a female socket arranged at the end of one stile.

10. The ladder system of any preceding claim, further comprising one or more additional clamps for clamping the two ladders together such that they form one continuous ladder.

11. The ladder system of claim 10, wherein the one or more additional clamps are attachable directly or indirectly to the stiles.

12. The ladder system of any preceding claim, when directly or indirectly dependent on claim 5, wherein at least one of the haunches includes a compressible pad between the adjacent haunches to transfer the compressive force imparted by the clamp, in use, from the clamp into the stile.

13. The ladder system of any preceding claim, when directly or indirectly dependent on claim 5, wherein an attachment means is provided to releasably attach the two haunches together in addition to the clamp.

14. The ladder system of any preceding claim, when directly or indirectly dependent on claim 5, wherein the haunches are attached to the ladder stiles by any one or more of welds, bolts, screws, rivets, pins, slotted fasteners and interlocking grips.

15. The ladder system of any preceding claim, wherein the clamp is an over-centre clamp.

16. The ladder system of any preceding claim, wherein the clamp is adjustable to select the compressive force imparted.

17. The ladder system of any preceding claim, further comprising a materials handling or personnel trolley for running along the stiles of the one continuous ladder.

18. A ladder system substantially as hereinbefore described with reference to the accompanying drawings.

Intellectual

Property

Office

Application No: GB1614203.6 Examiner: Monica Wright