GB2398337A

GB2398337A - A fall arrest system for use with a ladder

Info

Publication number: GB2398337A
Application number: GB0303036A
Authority: GB
Inventors: Stephen Murten
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-02-11
Filing date: 2003-02-11
Publication date: 2004-08-18
Also published as: GB0303036D0

Abstract

A system comprises a ladder (202), a support member (201) and a clamp (115) adapted to be clamped around the support member and having braking means, and connection means for connecting the clamp to an operative. The support member may be fixed to the ladder by permanent, temporary or adjustable fixing means. In one embodiment the braking means comprises a brake pad (306, Figure 3) connected to a brake arm (216), in a further embodiment the braking means comprises a cam. Preferably two safety clamps are used in tandem, each being attached to an operative. (Figure 12). As disclosed is a method of using a system as defined above.

Description

Safety Apparatus and Method

Background of the Invention

1. Field of the Invention

The present invention relates to apparatus and an associated method for an operative to perform ladder access.

2. Description of the Related Art

Ladder access is a technique for an operative to access an area, for example a part of a bridge during a structural inspection, using a ladder.

A problem with ladder access is ensuring that the operative performing the ladder access is safe and protected from injury during and following a fall from the ladder. To reduce the risk of injury to an operative performing ladder access, safety products that function to stabilise the ladder during use, or safety equipment that functions to reduce the impact of a fall upon the operative may be provided.

According to a first known technique of decreasing the risk of injury to an operative during ladder access, at least one rope and shunt combination is provided, in which the rope is anchored at a height above the height at which the operative is to access, and the shunt is configured to arrest a fall of a connected operative. A problem with this technique is the installation of the rope, which is timely and requires fall protection to be provided for the operative installing the rope. In addition, the rope may become entangled or damaged during use and therefore the supervision of the positioning of the rope is required.

According to a second known technique of decreasing the risk of injury to an operative during ladder access, a notched safety rail and a fall arrest device are provided, the notched safety rail being positioned upon a ladder and the fall arrest device being configured to travel within a channel in the rail and to arrest the fall of a connected operative. A problem with this technique is that a connected operative cannot quickly and easily relocate the fall arrest device from a rail during ladder access.

Brief Summary of the Invention

According to a first aspect of the present invention there is provided apparatus for an operative to perform ladder access comprising a ladder, a 0 support member, a safety clamp configured to be clamped around said support member, said clamp comprising braking means having a connection point, and connection means configured to provide a connection between said connection point and said operative; such that in use a first connection is provided between said operative and said connection point of the safety clamp by means of said connection means, said safety clamp is clamped around said support member such that a second connection is provided, said first and second connections provide a safety connection for said operative, and said operative performs ladder access whilst said safety connection is retained, wherein said braking means is configured to lock said safety clamp in place upon said support member in response to a fall of said operative whilst performing said ladder access.

Both the ladder and the support member may be portable or permanently fixed to a structure. The ladder may comprise temporary or permanent support member fixings, configured to support the support member either temporarily or permanently. The support member may be of solid or tubular construction.

According to a second aspect of the present invention there is provided a method for an operative to perform ladder access using apparatus comprising a ladder, a support member, a safety clamp configured to be clamped around said support member, said clamp comprising braking means having a connection point, and connection means configured to provide a connection between said connection point and said operative; said method comprising the steps of providing a first connection between said connection point and said operative by means of said connection means, clamping said safety clamp around said support member such that a second connection is provided, said first and second connections providing a safety connection for said operative, and said operative performing ladder access whilst said safety connection is retained, wherein said braking means is configured to lock said safety clamp in place upon said support member in response to a fall of said operative whilst performing said ladder access.

An operative may be provided with a second safety clamp and second connection means, so as to enable the operative to traverse an obstacle or a gap safely.

Brief Description of the Several Views of the Drawings The invention will now be described by way of example, with reference to the accompanying drawings of which: Figure 1 shows an operative performing ladder access using a first arrangement of apparatus and associated method according to the present invention; Figure 2 shows an enlarged view of the safety clamp shown in Figure 1, clamped around a support member; Figure 3 shows an enlarged view of the levered braking means of the safety clamp shown in Figure 2; Figure 4 shows a side view of the safety clamp shown in Figure 2 during a first stage of clamping around a support member; Figure 5 shows a rear view of the safety clamp shown in Figure 2 during a first stage of clamping around a support member; Figure 6 shows a rear view of the safety clamp shown in Figure 2 during a second subsequent stage of clamping around a support member; Figure 7 shows a rear view of the safety clamp shown in Figure 2 at 0 a third subsequent stage of clamping around a support member, in which the safety clamp has self locked around the support member; Figures 8 and 9 show an operative executing a first stage of unclamping the safety clamp shown in Figure 2 from around a support member; and Figure 10 shows an operative executing a second subsequent stage of unclamping the safety clamp shown in Figure 2 from around a support member; Figure 11 shows an operative performing ladder access using an alternative arrangement of apparatus and associated method according to the present invention; Figure 12 shows an operative performing ladder access using a further alternative arrangement of apparatus and associated method according to the present invention Written Description of the Best Mode for Carrying Out the Invention Figure 1 Figure 1 shows an operative 101 performing ladder access, using a first arrangement of apparatus and associated method, during an inspection of a building 102 having corrugated external walls 103 and a parapet wall 104.

The term "ladder access" is used herein as a reference to the technique of accessing an area using a ladder, and to indicate associated activities performed by an operative, including the activities of ascending or descending a ladder, preparing to ascend or descend a ladder, standing on a rung of the ladder, working from a ladder; and in general, any activity to where an operative is using a ladder configured and positioned for use.

Operative 101 is shown ascending a portable ladder 105 that comprises two substantially parallel side members 106 and a plurality of rungs 107 extending therebetween, substantially perpendicular to the side members 106 and substantially parallel to each other. At one end of the ladder 105, each side member 106 is shaped as a hook, such that ladder is configured to be hooked over parapet wall 104, as shown. To provide further stability, each end of the ladder 105 is provided with outrigging 108, that extends substantially perpendicularly from the ladder and is configured to extend across at least two adjacent corrugations in the walls 103 of the building 102. The outrigging 108 functions to inhibit the ladder 105 from rocking against the building 102.

Portable ladder 105 also comprises a first support member fixing 109 and a second support member fixing 110, which according to the arrangement shown in Figure 1, extend to one side of the ladder 105 from one of the side members 106. First support member fixing 109 is positioned at the hooked end of the portable ladder 105 and second support member fixing 110 is positioned at the other end thereof. Support member fixings 109,111 are configured to receive a support member 111. Support member 111 is configured to be removably installed within the fixings 109, 110, which are arranged such that when the support member 111 is retained by the support fixings 109, 110, the support member 111 extends substantially parallel to the side members 106 of ladder 105, as shown. According to the arrangement shown in Figure 1, support member 111 is an elongate solid bar having a substantially circular cross-section, and has a length greater than the distance between the first and second support member fixings 109, 110. First support member fixing 109 comprises an annular ring and 0 second support member fixing 110 comprises a cylindrical cup, with the open end facing towards the annular ring of the first support member fixing 110.

According to a preferred method of installing support member 111 into support member fixings 109, 110, one end of the support member 111 is progressed through the annular ring of the first support member fixing 109 towards the hooked end of the ladder 105, and when the other end of the support member 111 is brought past the open end of the cup of the second support member fixing 110, that end is fitted therein. The support member 111 is then retained by support member fixings 109, 110 until removed by a reverse method, and thus support member fixings 109, 110 are configured as temporary fixings for support member 111. The arrangement shown in Figure 1 and the above described method of installing support member 111 within the support member fixings 109, 110 of ladder 105, enable operative 101 to easily install the support member 111 when the ladder 105 is positioned for use against building 102.

As illustrated in Figure 1, operative 101 is wearing a safety harness 112, to which a first end of a lanyard 113 is connected. The anchorage point of lanyard 113 is shown in Figure 1 to be positioned in the chest area of operative 101, however, the anchorage point may be positioned in any other area of operative 101 located at or above waist height. The other end of lanyard 113 is connected to a karabiner 114, which is also connected to a safety clamp 115 configured as a fall arrest device. Safety clamp 115 is clamped around support member 111, thus lanyard 113 extends between operative 101 and support member 111. Safety harness 112, lanyard 113, karabiner 114 and safety clamp 115 are items of personal safety equipment, configured to be carried by operative 101, and in operation, 0 configured to be used exclusively by operative 101. Karabiner 114 provides a convenient releasable connection between lanyard 113 and safety clamp 115, thus enabling operative 101 to connect to safety clamp 115 quickly and easily.

As shown in Figure 1, operative 101 has one hand on one of the ladder rungs 107 and has both feet on a lower rung, making three points of contact between the operative 101 and the ladder 105.

In addition, a first connection between operative 101 and safety clamp 115 is provided by means of safety harness 112, lanyard 113 and karabiner 114 and a second connection is provided by means of clamping safety clamp 115 around support member 111. When both these first and second connections are provided, a safety connection is provided for operative 101. The safety connection provides operative 101 with fall arrest safety back up.

Operative 101 is shown performing ladder access according to a z preferred method for an operative to perform ladder access, in which the operative only performs ladder access whilst a safety connection is retained.

The utilization of a rigid support member 111 confers more security to operative 101 compared to a rope, due to the increased operational reliability of the support member and the ability to retain the support member in a known position throughout ladder access. In addition, safety clamp 115 is configured to be easily relocated during ladder access, as described below with reference to Figures 2-10.

Figure 2 Figure 2 shows an enlarged view of safety clamp 115 in operation, in the closed configuration, clamped around a support member 201.

According to the arrangement shown in Figure 2, support member 201 is a tube having a substantially circular cross-section, and is permanently fixed to one side of a portable ladder 202 by means of support member fixings 203.

Safety clamp 115 includes a collar 204, comprising a first collar section 205 and a second collar section 206, which can swing relative to each other about a spring loaded hinge 207. Collar 204 is configured to encompass support member 201 when in the closed configuration. Hinge 207 comprises a first hinge shaft 208 located upon first collar section 205 in alignment with a second hinge shaft 209 located upon second collar section 206. Hinge 207 is described in further detail with reference to Figure 4.

Safety clamp 115 also comprises a locking mechanism 210, configured to lock first collar section 205 and second collar section 206 together, in the closed configuration. Locking mechanism 210 is configured to simplify the installation of safety clamp 115 around a support member 201, by enabling operative 101 to clamp safety clamp 115 around support member 201 with a single operation, following reconfiguration of safety clamp 115 from the closed configuration to the open configuration. Locking mechanism 210, which is a releasable locking mechanism to enable safety clamp 115 to be conveniently relocated, is described in further detail with reference to Figures 5 to 10.

A feature of safety clamp 115 is a hand grip 211, located on second collar section 206, which functions to assist operative 101 in opening first collar section 205 and second collar section 206 apart from each other, for example, when operative 101 is unclamping safety clamp 115 from around support member 201.

Safety clamp further comprises two adjacent spaced apart positioning plates 212, located on and projecting from the outer surface of first collar section 205. Positioning plates 212 are arranged longitudinally upon first collar section 205, at a first edge of collar 204, and each positioning plate 212 defines an aperture (not shown) configured to receive a pivot bolt 213 therethrough.

Safety clamp 115 also comprises brake arm housing 214 which comprises side walls, a bottom wall and front walling within which a brake arm slot 215 is defined. Brake arm housing 214 is located on, and projects from, first collar section 205, at the other edge of collar 204. Brake arm housing 214 also defines the perimeter of an aperture (not shown) in first collar section 205.

Safety clamp 115 includes levered braking means 216, shown in further detail in Figure 3.

Figure 3 Levered braking means 216 comprises a lever handle 301, a brake arm 302, and a lever arm 303. Lever handle 301 defines a connection point 304, in this example an aperture, which provides a means for connecting lanyard 113 to safety clamp 115. Preferably, as shown in Figure 2, lanyard 113 is connected to levered braking means 216 by means of karabiner 114, which is configured to be loaded along the spine thereof. In addition, lever arm 303 defines a central pivot aperture 305 which is also configured to receive a pivot bolt 213 therethrough.

As shown in Figure 3, brake arm 302 comprises a brake pad 306.

Brake pad 306 is pivotally attached to the free end of brake arm 302, which defines an aperture (not shown). Extending substantially perpendicularly to from brake pad 306 is a connection portion 307, which also defines an aperture (not shown). To assemble brake pad 306 onto brake arm 302, a bolt 308 is inserted through the aperture defined by brake arm 302 and the aperture defined by connection portion 307, and is then secured in position, by for example a nut (not shown). Thus, bolt 308 acts as a pivot for brake pad 306.

Preferably, brake pad 306 has a corrugated surface contour 309.

Figure 3 also shows a spring 310, positioned around brake arm 302.

Referring to Figure 2, positioning plates 212 are spaced apart sufficiently to allow the insertion of lever arm 303 between them. During assembly of safety clamp 115, a pivot bolt 213 is inserted sequentially through the aperture (not shown) defined in a first positioning plate 212, through central aperture 305 defined in levered braking means 216 and through the aperture (not shown) defined in the second positioning plate 212. Pivot bolt 213 is then secured in position, by for example a nut (not 2s shown). Thus, pivot bolt 213 functions to connect levered braking means 216 to first collar section 205. In addition, pivot bolt 213 acts as a pivot for levered braking means 216.

As shown in Figure 2, levered braking means 216 is connected to and aligned with collar 204 such that brake arm 302 extends to one side of lever arm 303, and slots into brake arm slot 215 of brake arm housing 214 such that brake pad 306 is located facing the aperture (not shown) defined in first collar section 205.

Thus, with levered braking means 216 assembled to collar 204 as described above, spring 310, positioned around brake arm 302, is located within brake arm housing 214. Spring 310 is placed in compression when placed inside brake arm housing 214. A first end of spring 310 applies a 0 force against the front walling of brake arm housing 214 and the other end applies a force against brake pad 306. With the levered arrangement of braking means 216, which is pivoted about pivot bolt 213, brake pad 306 is pushed into contact with support member 201 under the action of spring 310. As previously described, brake pad 306 preferably has a corrugated surface contour 309. This feature functions to allow water upon support member 201 to drain through the brake pad 306, thus preventing contact between the brake pad 306 and the support member 201 from being broken by the presence of water between them.

The vertical position of safety clamp 115 upon support member 201 is maintained by the action of spring 310. The degree of contact between brake pad 306 and support member 201 under the force of the spring 310, however, allows safety clamp 115 to rotate around support member 201.

Thus, if a force applied to lanyard 113 causes lanyard 113 to change direction, for example when operative 101 moves from a first previous position to a second new position, safety clamp 115 can correspondingly rotate to align with the new direction of lanyard 113. This is advantageous in reducing cross-loading of lever handle 301 of levered braking means 216, in the event of a fall of operative 101.

Safety clamp 115 is configured such that safety clamp 115 will move up support member 201, in the direction of arrow 217, under a component of force applied to collar 204, in the direction of arrow 217. Similarly, safety clamp 115 is configured such that safety clamp 115 will move down support member 201, in the direction of arrow 218, under a component of force applied to collar 204, in the direction of arrow 218. Thus, operative 101 can conveniently adjust the vertical positioning of safety clamp 115 upon support member 201 using a single hand.

to Levered braking means 216 is configured such that when safety clamp 115 is in operation clamped around support member 201, levered braking means 216 is configured to activate under a force applied to lever handle 301 in the direction of arrow 311,down along the longitudinal axis of support member 201. With levered braking means 216 pivoted about pivot aperture 305, a component of force applied to lever handle 301 in the direction of arrow 311 (anti-clockwise) will cause brake arm 302, and thus brake pad 306, to advance in the direction of arrow 312 (anti- clockwise).

Such a force activates brake pad 306 such that brake pad 306 contacts support member 201 to provide a braking contact region, and is thus referred to hereinafter as a brake activating force. A braking contact region provides a means of braking safety clamp 115, and when a braking contact region is effected, safety clamp 115 is stopped in place upon support member 201.

A component of force applied to lever handle 301 in the direction of arrow 313 (clockwise) will cause brake arm 302 to advance in the direction of arrow 314 (clockwise), thus removing any contact between brake pad 306 and support member 201. Safety clamp 115 is configured such that it will move upwards along support member 201 under a component of force applied to lever handle 301 in the direction of arrow 313.

Thus, referring to the arrangement shown in Figure 1, safety clamp is configured to travel upwards along the longitudinal axis of support member 111 as operative 101 ascends ladder 105, the safety clamp 115 in effect following operative 101. However, levered braking means 216 is configured to prevent the safety clamp 115 from travelling down along the longitudinal axis of the support member 111 under a brake activating force.

In the event that operative 101 falls from ladder 105, the weight of operative to 101 transferred to the levered braking means 216 will cause brake pad 306 to contact support member 201, to arrest the fall. Thus, the weight of operative 101 during a fall is transferred to lever handle 301 as a brake activating force. Following a fall, operative 101 is supported by the support member 111.

Preferably, as shown in Figure 2, levered braking means 216 and locking mechanism 210 are located upon collar 204 opposite each other, such that an activating force applied to the lever handle 301 of levered braking means 216 acts in a direction through locking mechanism 210, to reduce forces acting to separate the two collar sections 205, 206 apart from each other.

Figure 4 Figure 4 shows operative 101 holding safety clamp 115 in the open configuration, with first collar section 205 opened apart from second collar section 206, in preparation for clamping safety clamp 115 around support member 201.

Safety clamp 115 is configured such that first collar section 205 and second collar section 206 can be held open apart from each other by means of hand grip 211. To hold safety clamp 115 in the open configuration, operative 101 has placed a hand 401 around levered braking means 216, such that a first digit 402 is positioned upon central arm 303 and a second digit 403 is positioned around hand grip 211. Operative 101 is shown sustaining safety clamp 115 in the open configuration by applying a force upon hand grip 211, acting in the direction of arrow 404, by pulling hand grip 211 with second digit 403.

Jo As previously described, first collar section 205 and second collar section 206 are configured to swing relative to each other about a spring loaded hinge 207. Hinge 207 comprises an internal hinge spring 405, having one end secured in a fixed position within first hinge shaft 208 and the other end secured in a fixed position within second hinge shaft 209.

With this arrangement, spring 405 is prevented from rotating within hinge 207. Spring 405 is arranged within hinge 207 such that it is in the relaxed position when safety clamp 115 is in the closed configuration. Thus, the action of opening first collar section 205 open apart from second collar section 206 causes first hinge shaft 208 to move relative to second hinge shaft 209; causing spring 405 to twist. The action of opening safety clamp transfers elastic energy to hinge spring 405, placing spring 405 in the energised position. In the energised position, the potential energy stored by spring 405 causes spring 405 to act to close first collar section 205 and second collar section 206 together; to return spring 405 to the relaxed position. Thus, with safety clamp 115 in the open configuration, if operative 101 released the grip upon hand grip 211, spring 405 would act to close safety clamp 115. In this way safety clamp 115 is self acting towards the closed configuration. Thus, safety clamp 115 comprises self closing means, in this example, in the form of spring loaded hinge 207.

As shown in Figure 4, operative 101 is progressing safety clamp 115 in the direction of arrow 406, further around support member 201.

Figure 5 Figure 5 shows a reverse angle of safety clamp 115 held in the same position as the position shown in Figure 4, and shows the components of locking mechanism 210 in further detail. Hinge 207 is configured to close to safety clamp 115 and locking mechanism 210 is configured to lock safety clamp 115 in the closed configuration. Thus, safety clamp 115 is self locking.

Locking mechanism 210 comprises a first hollow locking shaft 501 and a second hollow locking shaft 502 located longitudinally upon the outer surface of second collar section 206, adjacent the free edge thereof. First locking shaft 501 is positioned near a first edge of collar 204 and defines a positioning aperture 503 in the outer end thereof. Similarly, second locking shaft 502 is positioned near the other edge of collar 204, and defines a positioning aperture 504 in the outer end thereof.

Locking mechanism 210 includes a first release button 505, which comprises a first rod 506 having a first disc 507 at a first end thereof and a second disc 508 at the other end thereof. First release button 505 is assembled to move relative to first locking shaft 501. First rod 506 is inserted through first positioning aperture 503, and first disc 507 is positioned internally of first locking shaft 501 and second disc 508 is positioned externally of first locking shaft 501. In addition, a first release spring 509 is positioned around first rod 506, between second disc 508 and first positioning aperture 503. In the relaxed position of first spring 509, first disc 507 is positioned adjacent first positioning aperture 503. Thus, first release button 505 is resiliently mounted relative to first locking shaft 501. i Locking mechanism 210 further includes a second release button 510, which comprises a second rod 511 having a third disc 512 at a first end thereof and a fourth disc 513 at the other end thereof. Second release button 510 is assembled to move relative to second locking shaft 502.

Second rod 511 is inserted through second positioning aperture 504, and third disc 512 is positioned internally of second locking shaft 502 and fourth to disc 513 is positioned externally of second locking shaft 502. In addition, a second release spring 514 is positioned around second rod 511, between fourth disc 513 and second positioning aperture 504. In the relaxed position of second spring 514, third disc 512 is positioned adjacent second positioning aperture 504. Thus, second release button 510 is resiliently mounted relative to second locking shaft 502. ! In addition, locking mechanism 210 comprises a central hollow locking shaft 515 located longitudinally upon the outer surface of first collar section 205, adjacent the free edge thereof. Central locking shaft 515 defines a first pin aperture 516 at a first end thereof and a second pin aperture 517 at the other end thereof. Located internally of central locking shaft 515 is a pin spring 518, a first end of which abuts a first locking pin 519 and the second end of which abuts a second locking pin 520. First locking pin 519 has a first tapered surface 521, which tapers to a point as it extends away from pin spring 518, and similarly, second locking pin has a second tapered surface 522, which tapers to a point as it extends away from pin spring 518.

With pin spring 518 in the relaxed position, first locking pin 519 projects through first pin aperture 516, and second locking pin 520 projects through second pin aperture 517. Thus, first locking pin 519 and second i locking pin 520 are resiliently mounted relative to central locking shaft 515.

First locking pin 519 and second locking pin 520 are each retained in a fixed orientation within central locking shaft 515 by retaining means (not shown), such that first tapered surface 521 is orientated to face first locking shaft 501, and second tapered surface 522 is orientated to face second locking shaft 502.

0 As shown in Figure 2, when safety clamp 115 is in the closed configuration, first locking shaft 501, second locking shaft 502 andcentral locking shaft 515 are in alignment with each other.

Figure 6 Figure 6 shows safety clamp 115 during a second subsequent stage of clamping around support member 201, in which safety clamp 115 is in the process of self locking first collar section 205 and second collar section 206 together, in the closed configuration. Safety clamp 115 is configured such that as safety clamp 115 self closes, safety clamp 115 self locks.

Operative 101 has advanced safety clamp 115 further in the direction of arrow 406 to locate safety clamp 115 around support member 201 and, once the free end of first collar section 205 and second collar section 206 have advanced past the diameter of support member 201, has released hand grip 211 to allow safety clamp 115 to self close around support member 201 under the action of hinge spring 405.

Under the action of hinge spring 405, first collar section 205 advances in the direction of arrow 601, towards second collar section 206, and second collar section 206 advances in the direction of arrow 602, towards first collar section 205. As shown in Figure 6, first locking pin 519 comes into contact with first locking shaft 501. Similarly, second locking pin 520 comes into contact with second locking shaft 502. First collar section 205 and second collar section 206 are able to advance into the closed configuration, and simultaneously into a locked configuration, as described below.

As first collar section 205 and second collar section 206 advance towards each other, under the action of hinge spring 405, first locking shaft 0 501 pushes against first tapered surface 521 of first locking pin 519, thus pushing first locking pin 519 into central locking shaft 515, compressing pin spring 518, in the direction of arrow 603. Simultaneously, second locking shaft 502 pushes against second tapered surface 522 of second locking pin 520, thus pushing second locking pin 520 into central locking shaft 515, compressing pin spring 518, in the direction of arrow 604. As first locking pin 519 and second locking pin 520 are pushed further into central locking shaft 515, by first locking shaft 501 and second locking shaft 502 respectively, the amount of elastic potential energy stored by pin spring 518 increases. In addition, as first locking pin 519 and second locking pin 520 are pushed inwards into central locking shaft 515, first locking shaft 501, second locking shaft 502 and central locking shaft 515 are able to come into alignment, as shown in Figure 7.

Figure 7 Figure 7 shows safety clamp 115 during a third subsequent stage of clamping around support member 201, in which the safety clamp 115 has self closed and simultaneously self locked around support member 201.

As previously described, during the second stage of safety clamp clamping around support member 201, first locking pin 519 and second locking pin 520 are pushed inwards into central locking shaft 515, compressing pin spring 518, and transferring potential energy thereto. At the point at which first locking chamber 501, second locking chamber 502 and central locking 503 align, pin spring 518 releases the potential energy stored therein, to return pin spring 518 to the relaxed position. Thus, under this action of pin spring 518, first locking pin 519 is pushed, in the direction of arrow 701, through first pin aperture 516 such that first locking pin 519 0 projects through first pin aperture 516 into first locking shaft 501.

Simultaneously, second locking pin 520 is pushed, in the direction of arrow 702, through second pin aperture 517 such that second locking pin 520 projects through second pin aperture 517 into second locking shaft 502.

The action of first locking pin 519 and second locking pin 520 entering first locking shaft 501 and second locking shaft 502 respectively, locks safety clamp 115 in the closed configuration. Safety clamp 115 is configured to be closed and locked in the closed configuration in a single operation.

As described above, the present invention provides a safety clamp configured to be self locking, the safety clamp 115 being configured to be clamped around a support member by the method of applying force to the safety clamp 115 to sustain safety clamp 115 in an open configuration, locating the safety clamp 115 around a support member, and removing the force to reconfigure the safety clamp from the open configuration to the closed configuration.

It can be seen from Figure 7, that in the locked configuration of safety clamp 115, the position of first locking pin 519 relative to first locking shaft 501, and the position of second locking pin 520 relative to second locking shaft 502, prevent first collar section 205 and second collar section 206 from opening apart from each other. It can further be seen from Figure 7 that, in the locked configuration of safety clamp 115, the free end of first locking pin 519 abuts first disc 507 of first release button 505, and free end of second locking pin 520 abuts third disc 512 of second release button 510.

Figure 8 Figure 8 shows operative 101 executing a first stage of unclamping 0 safety clamp 115 from around support member 201. Operative 101 has placed a hand 801 around locking mechanism 210, such that a first digit 802 is positioned upon second disc 508 of first release button 505, and a second digit 803 is positioned upon fourth disc 513 of second release button 510. Operative 101 is shown applying a force to second disc 508, in the direction of arrow 804, such that first disc 507 pushes first locking pin 519, in the direction of arrow 804, into central locking shaft 515. Operative 101 is shown simultaneously applying a force to fourth disc 513, in the direction of arrow 805, such that third disc 512 pushes second locking pin 520, in the direction of arrow 805, into central locking shaft 515. The action of pushing first locking pin 519 and second locking pin 520 into central locking shaft 515 compresses pin spring 518. As operative 101 continues to depress first release button 505 and second release button 510, safety clamp 115 is reconfigured into a release configuration, which is illustrated in Figure 9.

Figure 9 As shown in Figure 9, in the release configuration, first release I button 505 is depressed to a position in which first locking pin 519 does not project into first locking shaft 501, and first disc 507 does not project into central locking shaft 515. Thus, first locking pin 519 is released from first locking shaft 501. Similarly, in the release configuration, second release button 510 is depressed to a position in which second locking pin 520 does not project into second locking shaft 502, and third disc 512 does not project into central locking shaft 515. Thus, second locking pin 520 is released from second locking shaft 502. l In the release configuration, first release spring 509, second release spring 514 and pin spring 518 are in compression. With first locking pin 519 and second locking pin 520 in the release configuration, as described above, first collar section 205 can be opened apart from second collar section 206, as shown in Figure 10.

Figure 10 As previously described, hinge 207 is spring loaded, such that hinge 207 acts to close first collar section 205 and second collar section 206 1 together, under the action of hinge spring 405, which is in the relaxed position when safety clamp 115 is in the locked configuration. Thus, to open safety clamp 115, a positive force acting to configure hinge spring 405 into the energised position is required. To achieve this, operative 101 has placed hand 401 around levered braking means 216, such that a first digit 402 is positioned upon central arm 304 and a second digit 403 is positioned around hand grip 211. Operative 101 is shown sustaining safety clamp 115 in the open configuration by applying a force upon hand grip 211, acting in the direction of arrow 1001, by pulling hand grip 211 with second digit 403.

This technique of sustaining safety clamp 115 in the open configuration to unclamp safety clamp 115 from around support member 201 is similar to the technique of sustaining safety clamp 115 in the open configuration in preparation for clamping safety clamp 115 around support member 201, as described with reference to Figure 4. After first collar section 205 and second collar section 206 have been opened apart from each other, pin spring 518 releases the energy stored within, to return to the relaxed position. In addition, the force applied to depress first release button 505 and second release button 510 is no longer required, and upon removal, 0 first spring 509 and second spring 514 release the energy stored within, to return to the relaxed position.

Referring to Figure 10, to complete the operation of unclamping safety clamp 115 from around support member 201, operative 101 holds safety clamp 115 in the open configuration whilst moving safety clamp 115, in the direction of arrow 1001, away from the support member 201.

Thus, the safety clamp 115 is configured to self lock in a closed configuration, the safety clamp 115 being configured to be clamped around a support member by the method of reconfiguring the safety clamp 115 from a closed configuration to an open configuration, locating the safety clamp 115 around a support member, and reconfiguring the safety clamp from the open configuration to the closed configuration.

Following the removal of safety clamp 115 from support member 201, operative 101 can release his grip on hand grip 211, and safety clamp will self lock in the closed configuration, as described above. Thus, when safety clamp 115 is in the closed configuration, safety clamp 115 is in the locked configuration.

Figure 11 Figure 11 shows operative 101 performing ladder access using a second arrangement of apparatus and the preferred method described with reference to Figure 1. Operative 101 is shown descending a ladder 1101 which is permanently attached to a brick wall 1102. Extending around the front of ladder 1101 is a security frame 1103, spaced along the length thereof, that provide security for operative 101. A support member 1104 is permanently attached to ladder 1101 by means of support member fixings to 1105. Operative 101 is provided with a safety connection, by means of safety harness 112, lanyard 113, karabiner 114 and safety clamp 115 all connected between operative 101 and support member 1104, as previously described. As operative 101 descends ladder 1101, operative 101 brings the safety clamp 115 down the support member 1104 with one hand 1106, in this example the left hand. Due to the presence of security frame 1103, support member 1104 is positioned at the front of one side of ladder 1101, in this example the left side, between the ladder 1101 and the security frame 1103. Thus, the fall arrest functionality provided by the safety connection is not hindered by the security frame 1103. In addition, by operative 101 using the hand on the same side as the support member 1104, the centre line of the body of operative 101 is retained within the side members 1107 of ladder 1101.

Figure 12 Figure 12 shows operative 101 after a fall whilst performing ladder access using a third arrangement of apparatus and a preferred associated method. Operative 101 has fallen from a ladder 1201, which is permanently attached to wall 1202. The apparatus further comprises a support member 1203, which is also permanently attached to wall 1202. There is no connection between ladder 1202 and support member 1203. Support member 1203 is attached to wall 1202 by means of a plurality of support member fixings 1204, and is positioned substantially parallel to ladder 1201. A support member fixing 1204 that is not at either end of support member 1203 is hereinafter referred to as an intermediate, for example intermediate 1205. An intermediate may be a support member fixing between the support member and a structure, or the support member and a 0 ladder.

Operative 101 is provided with a safety connection, by means of safety harness 112, lanyard 113, karabiner 114 and safety clamp 115 all connected between operative 101 and support member 1203, as previously described.

1s During ladder access using the arrangement shown in Figure 12, operative 101 must traverse each intermediate 1205 as encountered during ascent or descent of ladder 1201. To perform the traverse of intermediate 1205, operative 101 utilises a second safety connection provided by means of lanyard 1206, karabiner 1207 and a second safety clamp 1208, similar to lanyard 113, karabiner 114 and safety clamp 115, all connected between operative 101 and support member 1204, with one end of lanyard 1206 connected to safety harness 112, such that two lanyards 113, 1206 extend from the same harness.

Safety clamp 115 is configured to be clamped around and 2s unclamped from support member 1204 quickly and easily, and so an operative using a single safety clamp 115 could relocate a safety connection provided by means of the safety clamp 115 by this method.

However, a disadvantage of this method is that there is a period during which no safety connection is provided for the operative. The second safety clamp 1208 provides a method of relocating a safety connection, in which a safety connection is provided throughout. To traverse intermediate 1205, operative 101, in effect, relocates a safety connection, a preferred method of which is described below, with reference to Figure 12.

Initially, operative 101 descends ladder 1201 using safety clamp 115 only, thus, operative 101 is provided with a single safety connection. As safety clamp 115 approaches intermediate 1205 from above, operative 101, whilst the first safety connection is retained, clamps second safety clamp 1208 around support member 1204 immediately below the intermediate 1205, to provide a second safety connection. To complete the traverse, operative 101, whilst the second safety connection is retained, unclamps safety clamp 115 from around support member 1204, thus removing the first safety connection. With this method a safety connection above intermediate 1205 is relocated to below intermediate 1205, with at least one safety connection being provided and retained at each stage throughout. A safety connection below intermediate 1205 can be relocated to above intermediate 1205 using a similar method.

In addition, two safety connections can be provided for operative 101 by means of a safety clamp 115 being used in combination with support member 1204 and safety clamp 1208 being used in combination with a second support member. Thus, operative 101 can traverse intermediate 1205 according to a method similar to the above described method of relocating a safety connection, wherein safety clamp 1208 is clamped around the second support member to provide the second safety connection. Furthermore, operative 101 may use two safety clamps, in accordance with the method described to traverse an intermediate, to transfer a safety connection from one ladder section to a different spaced apart ladder section, for example a higher or lower ladder section. In this way, operative 101, may traverse a support member discontinuity or gap in safety.

As shown in Figure 12, operative 101 fell during a traverse of intermediate 1205. At the moment of the fall, both safety clamps 115, 1206 were clamped around support member 1204, and thus operative 101 was provided with two safety connections. As a result of the fall, both lanyards 113,1206 have become taut, transferring the weight of operative 101 to the lever handle 301 of each safety clamp 115, 1208 as a brake activating force. Thus, both safety clamps 115, 1208 have stopped in place upon support member 1204, and thus further fall of operative 101 is prevented.

Referring to Figure 1, with apparatus comprising a fixed length lanyard the distance that operative 101 could fall from ladder 105 is reduced as the height of the safety clamp 115 upon support member 111 is increased. Thus, increasing the height of safety clamp 115 relative to operative 101 can increase the level of safety provided by using safety clamp 115 within the described fall arrest system. Preferably, the length of lanyard 113 is less than 300mm, more preferably 50mm. The longer length the length of lanyard 113, the more movement operative 101 can make before having to adjust the position of the safety clamp 115, which is advantageous for operative 101 when climbing over the top of ladder 105 onto the roof of building 102, at which stage the safety connection for operative 101 would be retained. However, the longer the length of lanyard 113, the greater the distance operative 101 can fall. In addition, the longer the length of lanyard 113, the greater the pendulum swing of operative 101 following a fall from ladder 105.

Preferably, the distance between ladder 105 and support member 111 is approximately 75mm, such that there is sufficient room between ladder 105 and support member 111 for operative 101 to put one hand between, and to easily clamp and unclamp safety clamp 115 around and from support member 111. However, the greater the distance between ladder 105 and support member 111, the greater the pendulum swing of operative 101 following a fall from ladder 105.

In addition, referring to Figure 11, the greater the distance between ladder 1101 and support member 1104, the greater the cantilever effect on the support member fixings 1107 during and following a fall of operative 101 from ladder 1101.

As described above, the apparatus used by operative 101, in particular the arrangement of a ladder and a support member can take several forms. For example, the ladder may be portable or fixed to a structure, either by means of permanent or temporary fixings. The support member may be fixed to a structure, either by means of permanent or temporary fixings, or may be connected to the ladder by means of permanent or temporary fixings. For example, a support member may be bolted or welded to a ladder, bolted to a structure or may be removably connectable to a ladder by means of support member fixings, such as support member fixings 109, 110 of ladder 105 shown in Figure 1.

Support member fixings 109, 110 may be attached to ladder 105 by means of permanent or temporary fixings. Thus, the combination of a ladder and support member may be provided by means of a retrofit operation in relation to existing ladders. In addition, a ladder may be provided with adjustable support member fixings, such that the position of the support member relative to the ladder may be adjusted.

As described above, the support member can have a solid configuration, such as support member 111 shown in Figure 1, or a tubular configuration, such as support member 201 shown in Figure 2. Thus, if both support members 111, 201 have the same diameter and are made of the same material, the weight of support member 111 will be greater than the weight of support member 201. However, according to the arrangement shown in Figure 1, ladder 105 comprises support member fixings 109, 110 configured such that support member 111 can be temporarily installed therebetween, such that the support member 111 can be moved separate to the ladder 105. Thus, any extra weight of the support member 111 compared to support member 201, such as when both have the same diameter and are made from the same material, can also be carried in a separate load to ladder 105. However, due to the solid configuration of support member 111, additional weight due to the solid configuration can be reduced by decreasing the diameter of the support member 111.

Referring to Figure 2, which shows a support member 201 in the form of a tubular member having a substantially circular cross-section, the diameter of such a support member is preferably less than 48mm, which is the diameter of a standard scaffold pole, more preferably 38mm. Thus, referring again to Figure 1, the diameter of support member 111 may be less than 38mm. Corresponding to a reduction in diameter of support member 111, in order for the safety clamp 115 to be used effectively in combination with the support member 111, is a reduction in the dimensions 2s of the safety clamp 115. It is perceived that if an operative is to perform ladder access at a site at which several support members are installed at different locations, it would be preferable to standardise the dimensions of the support members such that a single safety clamp is suitable for use in combination with each. In addition, according to the arrangement shown in Figure 1, corresponding to a reduction in diameter of support member 111, in order for the support member to be used effectively in combination with the support member fixings 109, 110, is a reduction in the diameter of the annular ring of first support member fixing 109 and a reduction in the diameter of the cup of second support member fixing 110. According to the example shown in Figure 1, the depth of the cup of second support member fixing 110 is approximately 350mm.

0 An advantage with the arrangement shown in Figure 1, which comprises a portable ladder 105 and separately portable support member 111 (which can be temporarily supported by the support member fixings 109,110 extending from the ladder 105) is that both the ladder 105 and the support member 111 are portable and can thus be easily inspected at ground level. In addition, if the ladder 105 and support member 111 are configured as personal protective equipment, each will be inspected prior to each use. Thus, inspection of this equipment can be conveniently integrated into the preparation of the equipment for use.

Referring to Figure 1, according to an alternative arrangement of apparatus, lanyard 113 is replaced by a fall arrest webbing (not shown). To assemble the webbing to safety clamp 115, a first end of the webbing is passed through the aperture of connection point 304, doubled back upon itself and stitched together. The other end of the webbing can be connected to safety harness 112 worn by operative 101, by means of a karabiner, such as karabiner 114. The webbing comprises a rip stitch energy absorbing length, which is preferably concertinacd and stitched into a protective cover. The stitching is configured to break in the event of a fall of operative 101, to release the energy absorbing length. This action functions to reduce the fall arrest forces, and to control the deceleration distance.

Referring to Figure 1, according to a further alternative arrangement of apparatus, lanyard 113 is replaced by a fall restraint lanyard (not shown) , which has a plurality of connection points along the length thereof. Thus, whilst performing ladder access on the main body of ladder 105, operative 101 could connect to a connection point closer to safety clamp 115, thus reducing the effective length of the fall restraint lanyard. When operative 101 has reached the top of ladder 105, in preparation to climb over the top of ladder 105 and parapet wall 104 onto the roof of building 102, operative 101 could connect to a connection point further from safety clamp 115, such that a longer length of lanyard is provided.

Referring to Figures 2-10, which show safety clamp 115 in detail, according to an alternative arrangement of apparatus, levered braking means 216 comprises a cam in place of brake arm 302, connection portion 307 and brake pad 306.

Although a single example of safety clamp, safety clamp 115, is described, any safety clamp having a different construction but providing the same functionality as that described with respect to safety clamp 115 may be utilised. In addition, a safety clamp that does not have the described self locking functionality may be suitable for use. For example, an alternative safety clamp (not shown), has a locking shaft positioned near the free edge of each of the two collar sections, the locking shafts arranged to align with each other when the safety clamp is in the closed position, and the safety clamp further has a chain connecting a an elongate locking pin thereto. To lock the safety clamp in the closed position, the locking pin is inserted into the aligned locking shafts. This simpler construction advantageously reduces the weight of the safety clamp, compared to that of safety clamp 115.

Claims

Claims 1. Apparatus for an operative to perform ladder access comprising a

ladder, a support member, a safety clamp configured to be clamped around said support member, said clamp comprising braking means having a connection point, and connection means configured to provide a connection between said connection point and said operative; such that in use a first connection is provided between said operative and said connection point of the safety clamp by means of said connection means, said safety clamp is locked around said support member such that a second connection is provided, said first and second connections provide a safety connection for said operative, and said operative performs ladder access whilst said safety connection is retained, wherein said braking means is configured to stop said safety clamp in place upon said support member in response to a fall of said operative whilst performing said ladder access.
2. A method according to claim 1, wherein said ladder comprises at least one support member fixing.
3. A method according to claim 2, comprising at least one support member fixing permanently fixed to said ladder.
4. A method according to claim 2 or claim 3, comprising at least 5one support member fixing configured as a temporary fixing for said support member.
5. A method according to claim 4, comprising first and second support member fixings configured as temporary fixings for said support 10member, wherein said first support member fixing comprises an annular ring and said second support member fixing comprises a cup.
6. A method according to any of claims 2 to 5, comprising an adjustable support member fixing, such that the position of said support 5member relative to said ladder is adjustable.
7. Apparatus according to any preceding claim wherein said ladder comprises a security frame.
208. Apparatus according to any preceding claim wherein said connection means comprises a safety harness and a lanyard.
9. Apparatus according to any preceding claim wherein said braking means of said safety clamp comprises a brake pad connected to a 25brake arm.
10. Apparatus according to any of claims 1 to 8, wherein said braking means of said safety clamp comprises a cam.
11. Apparatus according to any preceding claim, wherein said connection point of said safety clamp comprises an aperture.
12. Apparatus according to any preceding claim, wherein said support member is a tubular member.

0
13. Apparatus according to any of claims 1 to 12, wherein said support member is a solid member.
14. Apparatus according to any preceding claim further comprising a second safety clamp configured to be clamped around a support member, said second clamp comprising second braking means having a second connection point, and second connection means configured to provide a connection between said second connection point and said operative; such that in use a third connection is provided between said operative and said second connection point of said second safety clamp by means of said second connection means, said second safety clamp is locked around said support member such that a fourth connection is provided, said third and fourth connections provide a second safety connection for said operative, and said operative performs ladder access whilst said first and second safety connections are retained, wherein said second braking means is configured to stop said second safety clamp in place upon said support member in response to a fall of said operative whilst performing said [adder access.
15. A method for an operative to perform ladder access using apparatus comprising a ladder, a support member, I a safety clamp configured to be clamped around said support member, said clamp comprising braking means having a connection point, and connection means configured to provide a connection between said connection point and said operative; said method comprising the steps of providing a first connection between said connection point and said operative by means of said connection means, clamping said safety clamp around said support member such that a second connection is provided, said first and second connections providing a safety connection for said operative, and said operative performing ladder access whilst said safety connection is retained, wherein said braking means is configured to stop said safety clamp in place upon said support member in response to a fall of said operative whilst s performing said ladder access.
16. A method according to claim 15, wherein said ladder comprises at least one support member fixing.
17. A method according to claim 16, comprising at least one 5support member fixing permanently fixed to said ladder.
18. A method according to claim 16 or claim 17, comprising at least one support member fixing configured as a temporary fixing for said support member.
19. A method according to claim 18, comprising first and second support member fixings configured as temporary fixings for said support member, wherein said first support member fixing comprises an annular ring and said second support member fixing comprises a cup.
20. A method according to any of claims 16 to 18, comprising an i adjustable support member fixing, such that the position of said support member relative to said ladder is adjustable.
21. A method according to any of claims 15 to 20, wherein said ladder comprises a security frame.
22. A method according to any of claims 15 to 21, wherein said connection means comprises a safety harness and a lanyard.
23. A method according to any of claims 15 to 22, wherein said braking means of said safety clamp comprises a brake pad connected to a brake arm.
24. A method according to any of claims 15 to 22, wherein said braking means of said safety clamp comprises a cam.
25. A method according to any of claims 15 to 24, wherein said connection point of said safety clamp comprises an aperture.
26. A method according to any of claims 15 to 25, wherein said support member is a tubular member. I
27. A method according to any of claims 15 to 26, wherein said support member is a solid member.
28. A method according to any of claims 15 to 27, wherein said apparatus further comprises i a second safety clamp configured to be clamped around a support member, said second clamp comprising second braking means having a second connection point, and second connection means configured to provide a connection between said second connection point and said operative; and said method comprises the further steps of providing a third connection between said second connection point and said operative by means of said second connection means, clamping said second safety clamp around said support member such that a fourth connection is provided, said third and fourth connections providing a second safety connection for said operative, and said operative performing ladder access whilst said first and second safety connections are retained, wherein said second braking means is configured to stop said second safety clamp in place upon said support member in response to a fall of said operative whilst performing said ladder access.