FIELD OF THE INVENTION

The present invention relates to a rope-ladder clamping apparatus and method.

BACKGROUND

Rope-ladders are known. They are used in a variety of different situations where a compact and often temporary ladder is required to be deployed a user. Although techniques exist for fixing those rope-ladders in place, the use of such fixings can have undesirable consequences. Accordingly, it is desired to provide an improved technique for fixing a rope-ladder.

SUMMARY

According to a first aspect, there is provided a rope-ladder clamping apparatus affixable to a holding surface, comprising: a clamp housing having a pair of rope clamps, each rope clamp being located receive a corresponding inter-rung rope portion of the rope- ladder, each rope clamp being actuatable to clamp against the corresponding inter-rung rope portion to retain the rope-ladder. The first aspect recognizes that many existing techniques for fixing a rope-ladder are unreliable. Accordingly, a rope-ladder clamping or fixing apparatus may be provided. The rope-ladder clamping apparatus may be fixable, retainable or connectable to a holding or retaining surface. The apparatus may comprise a clamp housing or body. The clamp housing may have a pair of rope clamps, cleats, jammers or clutches. Each rope clamp may be located or configured to receive a corresponding rope portion of the rope-ladder. Each rope clamp may receive the inter-rung rope portion or the portion of the rope-ladder between rungs. Each rope clamp may be actuatable or configurable to clamp against the corresponding inter-rung rope portion to retain, grip or fix the rope- ladder in place. In this way, a simple and reliable apparatus is provided which engages with the rope-ladder to hold it in place reliably, safely and securely.

Each rope clamp may be actuatable between a clamping configuration to retain the corresponding inter-rung rope portion and a non-clamping configuration to release the corresponding inter-rung rope portion. Accordingly, the rope-ladder clamping apparatus can be configured to either hold or release the rope-ladder by simply actuating the rope clamps. Each rope clamp may be displaceable between a first position which actuates each rope clamp into the clamping configuration and a second position which actuates each rope clamp into the non-clamping configuration. Accordingly, by simple movement of the rope clamps the rope-ladder can be held or released.

Each rope clamp may be a wedge or trapezoidal clamp.

Each rope clamp may be a narrowing wedge clamp which narrows or reduces in size in a first direction.

Each narrowing wedge clamp may comprise a pair of clamp blocks carried within a clamp channel which narrows in the first direction.

Each clamp block maybe spaced apart by a distance for receiving the corresponding inter-rung rope portion therebetween. Providing narrowing wedge clamps within a narrowing clamp channel causes a separation distance between the wedge clamps to change as they move along the clamp channel which varies a gripping force applied to the rope-ladder.

The distance between each clamp block may narrow in the first direction. Accordingly, the separation distance between the clamp blocks reduces as the clamp blocks move in the first direction, thereby increasing the gripping force on the rope-ladder.

Each rope clamp may comprise a coupling which couples each pair of clamp blocks.

The coupling may facilitate concurrent movement of each pair of clamp blocks. The coupling facilitates concurrent or simultaneous movement of both clamp blocks within the clamp channel to ensure that they remain in a fixed relationship on either side of the rope-ladder. In other words, the coupling ensures that the pair of clamp blocks move together within the clamp channel.

Each rope clamp may comprise a gripping surface shaped to enhance grip on the corresponding inter-rung rope portion. The provision of the gripping surface improves the friction or grip between the rope-ladder and the rope clamp.

Each rope clamp may comprise an actuation handle operable to displace each rope clamp between the first position which actuates each rope clamp into the clamping configuration and the second position which actuates each rope clamp into the non clamping configuration. Accordingly, an actuation handle maybe coupled with each rope clamp to facilitate movement of the rope clamp to grip or release the rope-ladder. This helps to ensure that the rope clamps are effectively gripping the rope-ladder and makes operating the rope-ladder clamping apparatus easier and more reliable for the user.

The actuation handle may comprise a recess configured to receive one of the pair of clamp blocks. The recess may be shaped to retain and/ or bear against the clamp block. Such an arrangement can help to at least partially decouple movement of the clamp block with respect to the actuation handle.

The actuation handle may comprise comprises a first shoulder and a second shoulder located at either end of the recess and positionable to bear against opposing ends of the one of the pair of clamp blocks to facilitate movement of the one of the pair of clamp blocks between the first position which actuates each rope clamp into the clamping configuration and the second position which actuates each rope clamp into the non clamping configuration. Accordingly, the recess may terminate with a pair of shoulders and each one of those shoulders can be moved to contact a corresponding end of the clamp block to help facilitate movement of the clamp block to either grip or release the rope-ladder.

The first shoulder may be positionable against a first end of the one of the pair of clamp blocks to facilitate movement of the one of the pair of clamp blocks in the first direction to actuate each rope clamp into the clamping configuration. Accordingly, the first shoulder may be moved to contact against the clamp block to move the clamp blocks to grip the rope-ladder.

The second shoulder may be positionable against a second end of the one of the pair of clamp blocks to facilitate movement of the one of the pair of clamp blocks in the second direction to actuate each rope clamp into the non-clamping configuration. Accordingly, the second shoulder may be moved to contact against the clamp block to move the clamp blocks to release the rope-ladder.

The recess may be longer than a length of the one of the pair of clamp blocks to facilitate further movement of the one of the pair of clamp blocks in the first direction without bearing against the second shoulder. Hence, the clamp block may slide within the recess under a surge load applied to the rope-ladder to enable an increased gripping force to be applied to the rope-ladder.

The first shoulder may comprise a biasing mechanism positioned between the first shoulder and an opposing end of the one of the pair of clamp blocks to bias the one of the pair of clamp blocks towards the first position which actuates each clamp into the clamping configuration. Accordingly, the biasing mechanism may provide a force on the clamp blocks to urge the clamp blocks towards the first position to maintain a tight gripping force on the rope-ladder

The actuation handle may extend from the clamp housing. This helps facilitate user interaction with the actuation handle.

The actuation handle may comprise a handle interlock operable to resist movement of the actuation handle in the second direction. Hence, the handle interlock may lock the handle in the first position in order to help prevent the gripping force on the rope- ladder from being released accidentally.

The handle interlock may comprise comprises a biasing member configured to engage with a detent to resist movement of the actuation handle in the second direction.

The actuation handle may comprise a handle coupled with a slider moveable between a first position which fills the detent to facilitate movement of the actuation handle in the second direction and a second position spaced away from the detent to resist movement of the actuation handle in the second direction.

The handle may be moveable to lock the slider in the first position.

The clamp housing may comprise a pair of elongate open channels extending through the clamp housing, each elongate open channel retaining a corresponding one of the pair of rope clamps and configured to receive the corresponding inter-rung rope portion therewithin. Hence, the rope-ladder can simply be laid into the open channels, which enables the rope-ladder to be flush with the fixing surface and the risk of accidental damage to the rope-ladder is reduced. Each elongate channel may extend uninterrupted through the clamp housing from a first surface to a second surface. In other words, the open channels may extend through the width of the clamp housing. The apparatus may comprise a pair of closing plates, each closing plate may be movable between a closed position which at least partially covers an associated elongate open channel and an open position which fails to cover the associated elongate open channel. Hence, the closing plates, when in the open position, enable the rope-ladder to be inserted into the open channels. However, when the closing plate is in the closed position, this at least partially encloses the rope-ladder within the open channels, which helps to prevent the rope-ladder inadvertently escaping from the open channels and helps to protect the rope-ladder in use.

Each closing plate may comprise a clamp interlock configured to prevent movement of the closing plate to the closed position when the handle is other than in the first position. Accordingly, the closing plate can only be fully closed when the handle has moved the clamp blocks to the gripping position. The closing plate therefore also helps to prevent movement of the actuating handle from the gripping position to prevent the inadvertent release of the rope-ladder. The provision of the clamp interlock also provides a visual and tactile confirmation to the user that the rope-ladder is being suitably gripped.

The clamp interlock may comprise a protrusion and complementary recess which align to allow movement of the closing plate to the closed position when the handle is in the first position.

Each closing plate may have a stability structure configured to engage with a complementary stability structure located on the clamp housing, either side of the associated elongate open channel, which when in the closed position resists widening of the associated elongate open channel. Hence, the closing plate and the clamp housing may inter-engage to prevent widening of the open channel and prevent inadvertent separation of the clamp blocks under high load which may otherwise cause reduced grip on the rope-ladder. Each closing plate may be pivotally received by the clamp housing for pivotal movement between the open position and the closed position. The clamp housing may comprise a pair of pivoting holders configured to receive a corresponding stanchion and facilitate movement of each stanchion between obstructing and unobstructing positions. The pivoting holders may receive a corresponding stanchion therein. The pivoting holders maybe movable between a position which obstructs use of the rope-ladder and an unobstructed position which facilitates use of the rope-ladder.

Each closing plates may comprise a stanchion aperture configured to prevent movement of an associated stanchion to the unobstructing position when the closing plate is other than in the closed position. Accordingly, the closing plate provides a further interlock which only enables the stanchions to be moved to the unobstructed position when the closing plate is in the closed position. Again, this helps to ensure that the rope-ladder is only used when it is firmly gripped by the clamp blocks. At least one of each stanchion and each pivoting holder may comprise a necked recess shaped to be received within the stanchion aperture when the closing plate is in the closed position to facilitate movement of the stanchion to the unobstructing position. The necked recess enables the stanchions to be moved to the unobstructing position only when the closing plate is in the closed position.

The necked recess may be shaped to overlay the stanchion aperture when the stanchion is in the unobstructing position to inhibit movement of the closing plate from the closed position. Accordingly, the necked recess also provides an interlock when in the unobstructing position which prevents movement of the closing plate away from the closed position, which in turn prevents movement of the actuation handle to the non clamping or release position.

The clamp housing may comprise a holding structure moveable between a retaining position to bear against a first rung to position the first rung away from a first major surface of the clamp housing and a free position which allows the first rung to contact the first major surface of the clamp housing upon movement in the first direction. Accordingly, the holding structure may be used to hold an adjacent rung away from the clamp housing while the rope-ladder is being clamped. In particular, the holding structure may position the rope-ladder so that the appropriate parts of the inter-rung rope portions are correctly aligned with extend through the open channels to enable the clamping blocks to grip onto those portions. The holding structure also holds the weight of the rope-ladder while the clamping and other interlocks are applied. Furthermore, positioning the rung away from the clamp housing enables the ladder to move slightly towards the clamp housing under additional surge loading to increase the clamping force exerted by the clamp blocks. The holding structure may be pivotally received centrally on the clamp housing between the pair of rope clamps to pivot between the retaining and free positions.

The rope clamps maybe mirrored about an axis extending along the first/second direction.

The clamp housing maybe mirrored about an axis extending along the first/second direction.

The first position may comprise a down-ladder position and the second position may comprise an up-ladder position.

The first direction may comprise a down-ladder direction and the second position may comprise an up-ladder direction. The apparatus may comprise the rope-ladder.

According to a second aspect, there is provided a method, comprising: providing a clamp housing having a pair of rope clamps; receiving a corresponding inter-rung rope portion of the rope-ladder with the pair of rope clamps; and actuating each rope clamp to clamp against the corresponding inter-rung rope portion to retain the rope-ladder.

The actuating may comprise actuating each rope clamp between a clamping configuration to retain the corresponding inter-rung rope portion and a non-clamping configuration to release the corresponding inter-rung rope portion.

The actuating may comprise displacing each rope clamp between a first position which actuates each rope clamp into the clamping configuration and a second position which actuates each rope clamp into the non-clamping configuration. Each rope clamp may be a wedge clamp.

Each rope clamp may be a narrowing wedge clamp which narrows in a first direction. Each narrowing wedge clamp may comprise a pair of clamp blocks carried within a clamp channel which narrows in the first direction. The method may comprise spacing each clamp block apart by a distance for receiving the corresponding inter-rung rope portion therebetween.

The distance between each clamp block may narrow in the first direction. Each rope clamp may comprise a coupling which couples each pair of clamp blocks.

The coupling may facilitate concurrent movement of each pair of clamp blocks.

The method may comprise providing each rope clamp with a gripping surface shaped to enhance grip on the corresponding inter-rung rope portion.

The actuating may comprise displacing an actuation handle to displace each rope clamp between the first position which actuates each rope clamp into the clamping configuration and the second position which actuates each rope clamp into the non- clamping configuration.

The actuation handle may comprise a recess configured to receive one of the pair of clamp blocks. The method may comprise configuring the actuation handle with a first shoulder and a second shoulder located at either end of the recess and positionable to bear against opposing ends of the one of the pair of clamp blocks to facilitate movement of the one of the pair of clamp blocks between the first position which actuates each rope clamp into the clamping configuration and the second position which actuates each rope clamp into the non-clamping configuration.

The actuating may comprise positioning the first shoulder against a first end of the one of the pair of clamp blocks to facilitate movement of the one of the pair of clamp blocks in the first direction to actuate each rope clamp into the clamping configuration.

The actuating may comprise positioning the second shoulder against a second end of the one of the pair of clamp blocks to facilitate movement of the one of the pair of clamp blocks in the second direction to actuate each rope clamp into the non-clamping configuration.

The method may comprise configuring the recess to be longer than a length of the one of the pair of clamp blocks to facilitate further movement of the one of the pair of clamp blocks in the first direction without bearing against the second shoulder.

The method may comprise configuring the first shoulder with a biasing mechanism positioned between the first shoulder and an opposing end of the one of the pair of clamp blocks to bias the one of the pair of clamp blocks towards the first position which actuates each clamp into the clamping configuration.

The method may comprise configuring the actuation handle to extend from the clamp housing.

The method may comprise providing the actuation handle with a handle interlock operable to resist movement of the actuation handle in the second direction.

The method may comprise providing the handle interlock with a biasing member configured to engage with a detent to resist movement of the actuation handle in the second direction.

The method may comprise configuring the clamp housing with a pair of elongate open channels extending through the clamp housing, each elongate open channel retaining a corresponding one of the pair of rope clamps and configured to receive the corresponding inter-rung rope portion therewithin.

The method may comprise configuring each elongate open channel to extend uninterrupted through the clamp housing from a first surface to a second surface.

The method may comprise providing a pair of closing plates, each closing plate being movable between a closed position which at least partially covers an associated elongate open channel and an open position which fails to cover the associated elongate open channel. The method may comprise providing each closing plate with a clamp interlock configured to prevent movement of the closing plate to the closed position when the handle is other than in the first position. The method may comprise providing the clamp interlock with a protrusion and complementary recess which align to allow movement of the closing plate to the closed position when the handle is in the first position.

The method may comprise providing each closing plate with a stability structure configured to engage with a complementary stability structure located on the clamp housing, either side of the associated elongate open channel, which when in the closed position resists widening of the associated elongate open channel.

The method may comprise pivotally receiving each closing plate by the clamp housing for pivotal movement between the open position and the closed position.

The method may comprise providing the clamp housing with a pair of pivoting holders configured to receive a corresponding stanchion and facilitate movement of each stanchion between obstructing and unobstructing positions.

The method may comprise providing each closing plate with a stanchion aperture configured to prevent movement of an associated stanchion to the unobstructing position when the closing plate is other than in the closed position. The method may comprise providing at least one of each stanchion and each pivoting holder with a necked recess shaped to be received within the stanchion aperture when the closing plate is in the closed position to facilitate movement of the stanchion to the unobstructing position. The method may comprise shaping the necked recess to overlay the stanchion aperture when the stanchion is in the unobstructing position to inhibit movement of the closing plate from the closed position.

The method may comprise providing the clamp housing with a holding structure moveable between a retaining position to bear against a first rung to position the first rung away from a first major surface of the clamp housing and a free position which allows the first rung to contact the first major surface of the clamp housing upon movement in the first direction.

The method may comprise pivotally receiving the holding structure centrally on the clamp housing between the pair of rope clamps to pivot between the retaining and free positions.

The method may comprise mirroring the rope clamps about an axis extending along the first/ second direction.

The method may comprise mirroring the clamp housing about an axis extending along the first/second direction.

The first position may comprise a down-ladder position and the second position may comprise an up-ladder position.

The first direction may comprise a down-ladder direction and the second position may comprise an up-ladder direction. The method may comprise affixing the clamp housing to the holding surface.

The method may comprise locating the rope-ladder in the clamp housing.

The method may comprise actuating the handle to actuate each rope clamp to the clamping configuration.

The method may comprise actuating the handle interlock to resist movement of the actuation handle in the second direction. The method may comprise moving the pair of closing plates to the closed position.

The method may comprise receiving each stanchion in a corresponding pivoting holder.

The method may comprise moving each stanchion to the unobstructing position.

The method may comprise moving the holding structure to the free position. The method may comprise de-actuating the handle interlock to enable movement of the actuation handle in the second direction.

The method may comprise actuating the handle to actuate each rope clamp to the non clamping configuration.

The method may comprise moving the holding structure to the retaining position.

The method may comprise moving each stanchion to the obstructing position.

The method may comprise moving the pair of closing plates to the open position.

The method may comprise removing the rope-ladder from the clamp housing.

The method may comprise removing each stanchion from each pivoting holder.

Further particular and preferred aspects are set out in the accompanying independent and dependent claims. Features of the dependent claims maybe combined with features of the independent claims as appropriate, and in combinations other than those explicitly set out in the claims.

Where an apparatus feature is described as being operable to provide a function, it will be appreciated that this includes an apparatus feature which provides that function or which is adapted or configured to provide that function.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be described further, with reference to the accompanying drawings, in which:

FIG. lA illustrates a rope-ladder clamping apparatus to according to one embodiment; FIG. lB illustrates an example installation;

FIG. 2 shows an enlarged view of a portion of a clamp housing in more detail;

FIG. 3 shows a holding structure in a holding position;

FIG. 4 illustrates the arrangement of a rope clamp in more detail;

FIGS. 5A to 5D illustrate the arrangement of clamp blocks in more detail and show their configuration in relation to an inter-rung rope portion;

FIG. 6 shows an actuating handle having moved the rope clamp to the clamping position; FIG. 7A shows a closing plate being prevented from pivoting to a closed position and FIG. 7B shows the closing plate being permitted to pivot to the closed position;

FIGS. 8A and 8B illustrate a clamp interlock mechanism;

FIG. 9 illustrates the holding structure pivoted to the closed position and stanchions in an obstructing position;

FIG. 10 illustrates further gripping of the clamp blocks in response to a surge load;

FIG. 11 illustrates the pivoting being depressed to enable the clamp blocks to be moved to release the rope-ladder;

FIG. 12 illustrates the clamp blocks in a rope-ladder release position; FIGS. 13 to 21B illustrate the configuration and operation of alternative arrangements of actuation handle

DESCRIPTION OF THE EMBODIMENTS

Before discussing the embodiments in any more detail, first an overview will be provided. Some embodiments provide a rope-ladder clamping apparatus which typically used for the temporary deployment of a rope-ladder. Typical rope-ladders have ropes extending through each end of each rung of the rope-ladder. The rope- ladder clamping apparatus may typically be fixed to a surface. The rope-ladder clamping apparatus has a pair of rope clamps, cleats, jammers or clutches, each of which receives the rope (sometimes a pair of ropes) extending through each end of each rung of the rope-ladder and provides a fast, safe and effective way of holding and releasing the rope-ladder while in some embodiments also provides a visual indication to a user of the clamping state of the rope-ladder. In particular, the user is typically provided with a visual indication which indicates when the rope-ladder is adequately clamped and safe to use and when it is not. Typically, a series of interlocks are provided which inhibit the visual indication that the ladder is safe to use unless all those interlocks are in place. Those interlocks also help prevent the rope-ladder clamping apparatus from being inadvertently reconfigured to a non-clamping or release configuration. Although the following examples illustrate the use of jammers, it will be appreciated that other types of clamps such as clutches may also be used.

Rope Clamping Apparatus

FIG. lA illustrates a rope-ladder clamping apparatus 10 according to one embodiment. The rope-ladder clamping apparatus 10 comprises a clamp housing 20 which receives and retains a rope-ladder 30 to hold the rope-ladder 30 in place. The rope-ladder 30 is formed by two pairs of ropes which extend through a number of rungs 40, although two single rope arrangements are common. Hence, the rungs 40 are spaced apart by an inter-rung rope portion 50 and, in this arrangement, those inter-rung rope portions 50 are each formed from a pair of ropes.

The clamp housing 20 has a pair of channels 60A, 60B which extend through the clamp housing 20 and which receive the inter-rung rope portions 50. The channels 60A, 60B are provided with rope clamps which clamp onto the inter-rung rope portions 50 to hold the rope-ladder 30 in place. The clamp housing 20 has a number of interlocks which prevent plates from being folded into closed positions, which in turn prevents a pair of stanchions 70A, 70B from being pivoted into an unobstructed (vertical) position, as shown in FIG. lA, unless the rope-ladder 30 is correctly inserted into, and correctly clamped by, the rope clamps, as will be explained in more detail below.

Figure lB shows an example installation of the rope-ladder clamping apparatus 10 which has the clamp housing 20 affixed to a holding surface, such as the deck of a ship or part of a building. In this arrangement, a guide plate 80 is provided which fits over a corner of the holding surface to help guide the rope-ladder 30 and prevent damage to the inter-rung rope portions 50. As is most clearly understandable from FIG. lB, it can be seen that there is an up-ladder direction U and a down-ladder direction D. In a typical installation, a he majority of the rope-ladder 30 will extend from the clamp housing 20 in the down-ladder direction D, depending, of course, on the length of the rope-ladder 30 and the height of the drop.

Clamp Housing

FIG. 2 shows an enlarged view of a portion of the clamp housing 20 in more detail. The channel 60A can be seen extending from a first surface 90 on the up-ladder side of the clamp housing 20 through the clamp housing 20 to a second surface too on the down- ladder side of the clamp housing 20. A rope clamp 110 is provided within the channel 60A. An actuation handle 120 is coupled with the rope clamp 110 and is actuatable to assist movement of the rope clamp 110 within the channel 60A.

A pivoting holder 130 is provided which receives an end of the stanchion 70A. A closing plate 140 is pivotally received on the clamp housing 20 and pivots between an open position as illustrated in FIG. 2 and a closed position as illustrated in FIG. lA. A holding structure 150 is pivotally received on the clamp housing 20 and pivots between a holding position as shown in FIG. 3, where an up-ladder rung 40A is held in place by the holding structure 150 by the weight of the rope-ladder 30 extending in the down- ladder direction D from the clamp housing 20 and a closed position (see FIG. lA). Rope Clamp

FIG. 4 illustrates the arrangement of the rope clamp 110 in more detail. The rope clamp 110 comprises a pair of clamp blocks 150A, 150B which are retained within a narrowing channel 160. The channel 160 is wider in the up-ladder direction U towards the first surface 90 and narrows in the down-ladder direction D towards the second surface too. The clamp blocks 150A, 150B in this example are wedge clamp blocks which also narrow in the down-ladder direction D. Actuation Handle

The actuation handle 120 has an elongate portion 170 and an operating portion 180 which extends transversely from an end of the elongate portion 170. The elongate portion 170 defines a recess portion 190 bounded by a first shoulder 200 and a second shoulder 210. A spring 205 extends from the first shoulder 200 and operates to apply an urging force against the clamp block 150A in the down-ladder direction D. The actuation handle 120 operates to help move the clamp blocks 150A, 150B between a non-clamping configuration as shown in FIG. 4 and a clamping configuration, as will be described in more detail below. Hence, the actuation handle 120 can be moved within the channel 160 to cause the inter-rung rope portion 50 to be clamped to hold the rope- ladder 30 in place or unclamped to allow the rope-ladder 30 to be removed from, or placed into, the channels 60A, 60B of the clamp housing 20. The elongate portion 170 also comprises a recess 220 which cooperates with the closing plate 140 to allow the closing plate 140 to move to the closed position when the actuation handle 120 is moved to a position where the clamp blocks 150A, 150B are clamping the inter-rung rope portion 50, as will be explained in more detail below. The elongate portion 170 also comprises a pair of notches 230A, 230B which cooperate with a pivoting lever 240 which helps retain the actuation handle 120 in either a clamping position or a non clamping position, as will also be explained in more detail below. Clamp Blocks

FIGS. 5A to 5D illustrate the arrangement of the clamp blocks 150A, 150B in more detail and show their configuration in relation to the inter-rung rope portion 50. FIG. 5A is an underside view of the clamp blocks 150A, 150B. As can be seen, a rigid coupling 250 couples clamp block 150A with clamp block 150B. The coupling 250 is pivotally received to enable the clamp blocks 150A, 150B to vary in separation distance as they move within the channel 160. As can be seen in FIG. 5B, planar surfaces 260, 270 of the clamp blocks 150A, 150B which bear against the surface of the channel 160 and/ or the recess 190 have a low friction in order to facilitate movement of the clamp blocks 150A, 150B within the channel 160 and recess 190. FIG. 5B is an end-on view of the clamp blocks 150A, 150B showing recesses 280, 290 shaped to receive the inter rung rope portion 50 of the rope-ladder 30. In this example, the inter-rung rope portion 50 comprises a pair of ropes and so a pair of recesses 280, 290 are provided.

As can be seen most clearly in FIG. 5D, the recesses 280, 290 have a surface shaped to fit and engage with a surface of the inter-rung rope portions 50 to improve grip between the clamp blocks 150A, 150B and the inter- rung rope portion 50. Rope-Ladder Fitting

The clamp housing 20 is first fixed to a holding surface as illustrated in FIG. lB. Then the rope-ladder is placed next to the clamp housing 20. The holding structure 150 is pivoted to the holding position, the closing plates 140 are pivoted to the open position and the stanchions 70A, 70B are typically absent. The rope clamps 110 are moved by the actuation handle 120 to the non-clamping position shown in Figure 2 and are retained in this position by the pivoting lever 240 engaging with the recess 230B. The up-ladder rung 40A is placed next to the holding structure 150 and the adjacent inter rung rope portion 50 is inserted into the channels 60A, 60B, typically by rolling the rope-ladder 30.

As shown in FIG. 6, after inserting the inter-rung rope portion 50 between the clamp blocks 150A, 150B, the pivoting lever 240 is depressed and the actuation handle 120 is moved in the down-ladder direction D which causes the first shoulder 200 to bear against a facing surface of the clamp block 150A, which in turn causes the clamp block 150A together with the clamp block 150B to move in the down-ladder direction D. The narrowing of the channel 160 causes the separation distance between the clamp blocks 150A, 150B to reduce, causing the inter-rung rope portion 50 to be clamped or squeezed by the clamp blocks 150A, 150B. The actuation handle 120A is prevented from moving any further when the distal end of the elongate portion 170 and the shoulder 210 bear against the blind end of the channel 160. Once in this position, the pivoting lever 240 engages with the recess 230A and this resists movement of the actuation handle 120 in the up-ladder direction U. With the actuation handle 120 in this position, the rope-ladder 30 is gripped and held in place by the clamp blocks 150A, 150B. Closing Plate

As shown in FIG. 7 A, when the actuation handle 120 is not in the clamping position (FIG. A shows the actuation handle 120 in the position illustrated in FIG. 4) then the closing plate 140 is unable to pivot to the closed position shown in Figure lA. This prevents a necked recess of the pivoting holders 90 or the stanchion 70B from being received within a stanchion aperture 300 formed in the closing plate 140, which prevents the stanchion 70B from being pivoted from the obstructing (inclined, typically to 45 ⁰ so that the stanchions impede a user passing over the clamp housing 20) position to the unobstructing position.

As can be seen in FIG. 7B, when the actuation handle 120 is in the clamping position, the recess 220 aligns with a depending face of the closing plate 140, which allows the closing plate 140 to pivot to the closed position. When in this position, the necked recess of the pivoting holders 90 or the stanchion 70B can be received within the stanchion aperture 90 to enable the stanchion 70 B to be pivoted to the unobstructing position as shown in FIG lA.

Clamp Interlock

FIGS. 8A and 8B illustrate a clamp interlock mechanism which helps to prevent movement of the clamp block 150A away from the clamp block 150B, which would result in a reduction in the clamping force on the rope-ladder 30. In particular, the clamp housing 20 comprises a number of upstanding collets 308 which protrude from a surface which receives the closing plate 140. The closing plate 140 is provided with a number of apertures 310 which are shaped and positioned to align with the collets 308 when the closing plate 140 is in the closed position, as illustrated in FIG. 8B. Receiving the collets 308 within the apertures 310 helps to prevent reaction forces on the clamp blocks 150A, 150B deforming the channel 160, causing the clamp blocks 150A, 150B to move apart, reducing the clamping force on the inter-rung rope portion 50. Stanchions

FIG. 9 illustrates that once the actuation handles 120 have been moved to the clamping position and the clamp blocks 150A, 150B are now clamping the rope-ladder 30, the holding structure 150 can be pivoted away from the up-ladder rung 40A to cover a central portion of the clamp housing 20. The stanchions 70A, 70B can now be moved from the obstructing position illustrated in FIG. 9 to the unobstructing positions, as illustrated in FIG. lA and the rope-ladder 30 is securely fixed for use. As can be seen in FIG io, should a surge load be applied to the rope-ladder 30 then rather than the rope potentially slipping between the clamp blocks 150A, 150B, instead the spacing away of the up-ladder rung 40A by the holding structure 150 together with the additional travel enabled by the recess 190 enables the clamp blocks 150A, 150B to move further within the channel 160 in the down-ladder direction D to a maximum clamping position until it bears against shoulder 210 to further reduce the separation distance between the clamp blocks 150A, 150B to further increase the gripping force on the inter-rung rope portion 50. Hence, in the most heavily-loaded situation, both the clamp blocks 150A, 150B exert the maximum gripping force on the inter-rung rope portion 50 as well as the up-ladder rung 40A now being positioned to bear directly against the clamp housing 20, as illustrated in FIG. 10.

Ladder Removal

As shown in FIG. 11, when it is desired to release the rope-ladder 30 from the clamp housing 20, first the pivoting lever 240 is depressed to disengage from the recess 230. Then, as shown in FIG 12, the actuation handle 120 is moved in the up-ladder direction U which causes the shoulder 210 to abut against an end surface of the clamp block 150A which enables the clamp blocks 150A, 150B to be moved along the channel 160 in the up-ladder direction U. This allows the distance between the clamp blocks 150A, 150B to increase, reducing the grip on the inter-rung rope portion 50.

The stanchions 70A, 70B are moved to the obstructing position by pivoting the stanchion holders 90. This enables the closing plates 140 to be pivoted to an open position, exposing the channels 60A, 60B. Either prior to moving the actuation handle 120 in the up-ladder direction U (should the up-ladder rung 40A still be spaced from the clamp housing 20) or once the actuation handle 120 has been moved to the non clamping position illustrated in FIG. 12, the rope-ladder 30 can be pulled temporarily to the position shown in FIG. 12 and the holding structure 150 pivoted to bear against the up-ladder rung 40A. This allows the remainder of the rope-ladder 30 to be retrieved and, once it has been retrieved, the inter-rung rope portion 50 can be removed from the clamp housing 20. The stanchions 70A, 70B can then either be removed or retained in the obstructing position and the closing plates 140 and holding structure 150 moved to the closed position to protect the clamp housing 20. Actuation Handle - Alternative Arrangements

FIG. 13 illustrates an alternative arrangement of actuation handle 120A. In this arrangement, the actuation handle 120A is fixed directly to the clamping block 150A (for example using bolts) rather than allowing the clamping block 150A to sit within the recess 190. In this arrangement, the elongate portion 170’ has a recess 230B’ and a shoulder 230’. In addition, the slot 220’ is wider, extending further along the elongate member 170. As can be seen in FIG. 13, when the actuation handle 120A is in the non clamping position, the pivoting lever 240 engages with the recess 230B’. When the rope-ladder 30 is to be clamped then the actuation handle 120A is moved in the down- ladder direction D until the pivoting lever 240 bears against the shoulder 230A’ and the clamp blocks 150A, 150B are in the clamping position as shown in FIG. 14. The location of the slot 220’ enables the closing plates 140 to be pivoted to the closed position, as illustrated in FIG. 17.

FIG. 18A illustrates a further alternative arrangement of actuation handle 120B. In this arrangement, a truncated pivoting lever 240B is provided. Instead of the pivoting lever 240B being actuated directly, a handle 185B coupled with a slider member 175B operates to prevent and allow engagement between an engaging end of the pivoting lever 240B and a recess 230B”.

In particular, as illustrated in FIGS. 18A to 18C, the slider member 175B is in a disengaged position which allows the engaging end of the pivoting lever 240B to enter the recess 230B” to hold the clamping handle 120B in the clamping position and to prevent movement in a similar manner to that described above. However, as illustrated in FIGS. 19A to 19C, movement of the actuation handle 185B causes a corresponding movement of the slider member 175B which causes a shoulder 177B to bear against the engaging end of the pivoting lever 240B and fill the recess 230B”. This enables the clamping handle 120B to be actuated to the non-clamping position. As illustrated in FIGS. 20A to 20C, the actuation handle 185 can be rotated to a locking position which holds the sliding member 175B in place to enable the clamping handle 120B to be actuated to the non-clamping position. The operation can be reversed to remove the shoulder 177B, to allow the engaging end of the pivoting lever 240B to fill the recess 230B” to hold the clamping handle 120B in the clamping position.

FIGS. 21A and 22B illustrates a yet further alternative arrangement of actuation handle 120C. In this arrangement, a linearly-biased pin 240C is provided which is urged by a spring. The pin 240C has a chamfered engaging end which is received within a recess 230B’” to hold the clamping handle 120C in the clamping position and to prevent movement in a similar manner to that described above. Movement of an actuation handle causes a corresponding movement of a slider member which causes a shoulder to bear against the chamfered engaging end of the pin 240C and fill the recess 230B’”. This enables the clamping handle 120C to be actuated to the non-clamping position. The operation can be reversed to remove the shoulder, to allow the chamfered engaging end of the pin 240C to fill the recess 230B’” to hold the clamping handle 120C in the clamping position.

Should the rope-ladder 30 undergo a surge in load, then the clamp blocks 150A, 150B, together with the actuation handle 120A, can move further with the inter-rung rope portion 50 in the down-ladder direction D, which reduces the separation distance between the clamp blocks 150A, 150B and increases the gripping force on the inter- rung rope portion 50 to a maximum clamping position (see FIG. 15). The elongate nature of the slot 220’ as well as the shoulder 230A’ facilitates this movement even when the closing plates 140 are in the closed position, as illustrated in FIG. 15. To release the rope-ladder 30, the actuation handle 120A is moved in the up-ladder direction U until the shoulder 230A’ bears against the pivoting lever 240 (see FIG. 14). The pivoting lever 240 is then depressed to allow the actuation handle to be moved further in the up-ladder direction U until the pivoting lever 240 engages with the recess 230B’ which retains the clamp blocks in the non-clamping position to allow the rope- ladder 30 to be removed (see FIG. 13) Although illustrative embodiments of the invention have been disclosed in detail herein, with reference to the accompanying drawings, it is understood that the invention is not limited to the precise embodiment and that various changes and modifications can be effected therein by one skilled in the art without departing from the scope of the invention as defined by the appended claims and their equivalents.