GB2392950A

GB2392950A - Self locking safety clamp

Info

Publication number: GB2392950A
Application number: GB0220929A
Authority: GB
Inventors: Stephen Murten
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-09-10
Filing date: 2002-09-10
Publication date: 2004-03-17
Anticipated expiration: 2022-09-10
Also published as: GB2392950B; GB0220929D0

Abstract

A safety clamp 112 for use within a fall arrest system, in which safety clamp 112 in operation is clamped around a scaffold pole 102, configured to self lock around the scaffold pole 102. The safety clamp 112 comprises a first collar section 202 and a second collar section 203 configured to swing relative to each other about a spring loaded hinge 204, which is configured to self close the first collar section 202 and the second collar section 203 together in a closed configuration. The safety clamp 112 further comprises an automatic locking mechanism 207 configured to releasably self lock the first collar section 202 and the second collar section 203 together in the closed configuration.

Description

Safety Clamp Background of the Invention

1. Field of the Invention

5 The present invention relates to a safety clamp, in particular to a safety clamp for use within a fall arrest system.

2. Description of the Related Art

Safety equipment for use within a variety of fall arrest systems are to known. A safety clamp for use within a fall arrest system is disclosed in United Kingdom patent application number GB 01 10 594.9 in the name of the present applicant. The disclosed safety clamp includes a tube catchment device formed from two sections, configured to self close around a scaffold tube. The safety clamp also includes a locking device with a locking pin, to 15 enable the safety clamp to be locked in the closed position. The locking device comprises two locking tubes, located one on each section, arranged to align with each other when the two sections are closed together. To lock the safety clamp in the closed position, the locking pin is inserted into each locking tube, to prevent them from opening apart. With this type of safety 20 clamp, the closing of the safety clamp around a scaffold pole and the locking of the safety clamp in the closed position is performed in two operations, which is time consuming and awkward for the user. In addition, a safety clamp that has self closed around a scaffold pole may appear to be locked in the closed position when it is not. If the operative does not perform the 2 locking operation, for example if the operative forgets to do so, the operative may not become aware that the safety clamp is not locked around the

scaffold pole until the operative falls and the safety clamp fails to arrest the fall. Brief Summary of the Invention

5 According to a first aspect of the present invention there is provided a safety clamp for use within a fall arrest system in which said clamp in operation is clamped around an elongate support member, said safety clamp comprising a first collar section and a second collar section wherein said safety clamp is configured to self lock said first collar section and said second 10 collar section together.

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 operatives each connected by a safety clamp embodying the present invention to a scaffold pole constituting part of a scaffold structure; Figure 2 shows an enlarged view of a safety clamp shown in Figure 1, clamped around a scaffold pole; 20 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 scaffold pole; Figure 5 shows a rear view of the safety clamp shown in Figure 2 25 during a first stage of clamping around a scaffold pole;

Figure 6 shows a rear view of the safety clamp shown in Figure 2 during a second subsequent stage of clamping around a scaffold pole, in which the safety clamp is self-locking around the scaffold pole; Figure 7 shows a rear view of the safety clamp shown in Figure 2 at a 5 third subsequent stage of clamping around a scaffold pole, in which the safety clamp has self locked around the scaffold pole; Figures 8 and 9 show an operative executing a first stage of unclamping the safety clamp shown in Figure 2 from around a scaffold pole; and 10 Figure 10 shows an operative executing a second subsequent stage of unclamping the safety clamp shown in Figure 2 from around a scaffold pole. Written Description of the Best Mode for Carrying Out the Invention

15 Figure 1 A scaffold structure 101 is shown in Figure 1, having vertical scaffold poles 102,103 horizontal scaffold poles 104, transversal scaffold poles 105 and flat sections 106. In addition, the scaffold structure 101 may also include diagonal strengthening poles.

20 In Figure 1, an operative 107 is shown traversing around open trap door 108 in flat section 106. Operative 107 is wearing a safety harness 109, to which a first end of a lanyard 110 is connected. The other end of lanyard 110 is connected to a karabiner 111, which is connected to a safety clamp 112 according to a preferred embodiment of the present invention. Safety as clamp 112 is clamped around a vertical scaffold pole 102, thus lanyard 110 extends between operative 107 and scaffold structure 101. Safety clamp 112

is personal safety equipment, configured to be carried by operative 107, and in operation, configured to be used exclusively by operative 107. Safety clamp 112 provides a first safety connection for operative 107, and is configured to arrest a fall of operative 107. Karabiner 111 provides a 5 convenient releasable connection between lanyard 110 and safety clamp 112, thus enabling operative 107 to connect to safety clamp 112 quickly and easily. Figure 2 0 Figure 2 shows an enlarged view of safety clamp 112 in operation, in the closed configuration, clamped around vertical scaffold pole 102. Safety clamp 112 includes a collar 201, comprising a first collar section 202 and a second collar section 203, which can swing relative to each other about a spring loaded hinge 204. Collar 201 is configured to encompass scaffold pole 102 when in the closed configuration. Hinge 204 comprises a first hinge shaft 205 located upon first collar section 202 in alignment with a second hinge shaft 206 located upon second collar section 203. Hinge 204 is described in further detail with reference to Figure 4.

Safety clamp 112 also comprises an automatic locking mechanism 20 207, configured to lock first collar section 202 and second collar section 203 together, in the closed configuration. Automatic locking system 207 is configured to simplify the installation of safety clamp 112 around a scaffold pole 102, by enabling operative 107 to clamp safety clamp 112 around scaffold pole 102 with a single operation. Automatic locking system 207, as which is a releasable locking mechanism to enable safety clamp 112 to be conveniently relocated, is described in further detail with reference to Figures

5to 10.

A feature of safety clamp 112 is a hand grip 208, located on second collar section 203, which functions to assist operative 107 in opening first collar section 202 and second collar section 203 apart from each other, for example, when operative 107 is unclamping safety clamp 112 from around scaffold pole 102.

Safety clamp further comprises two adjacent spaced apart positioning plates 209, located on and projecting from the outer surface of first collar section 201. Positioning plates 209 are arranged longitudinally upon first 10 collar section 201, at a first edge of collar 201, and each positioning plate 207 defines an aperture (not shown) configured to receive a pivot bolt 210 therethrough. Safety clamp 112 also comprises brake arm housing 211 which comprises side walls, a bottom wall and front walling within which a brake arm slot 212 is defined. Brake arm housing 211 is located on, and projects from, first collar section 201, at the other edge of collar 201. Brake arm housing 211 also defines the perimeter of an aperture (not shown) in first collar section 202.

Safety clamp 112 includes levered braking means 213. Preferably, as 20 shown in Figure 2, levered braking means 213 and automatic locking mechanism 207 are located upon collar 201 opposite each other, such that force acting upon lever handle 301, transferred through safety clamp 112, will act through the automatic locking mechanism 207.

25 Figure 3

Levered braking means 213 is shown in further detail in Figure 3.

According to the preferred embodiment of the present invention, levered braking means 213 is substantially shaped as a three pronged fork, having a lever handle 301, a first brake arm 302, a second brake arm 303 and a 5 central brake arm 304. Lever handle 301 defines a connection aperture 305, which provides a means for attaching lanyard 209 to safety clamp 112.

Preferably, as shown in Figure 2, lanyard 110 is connected to levered braking means 213 by means of karabiner 111, which is configured to be loaded along the spine thereof. In addition, central brake arm 304 defines a central 10 pivot aperture 306 which is also configured to receive a pivot bolt 210 therethrough. As shown in Figure 3, first brake arm 302 comprises a first brake pad 307. First brake pad 307 is pivotally attached to the free end of first brake arm 302, which defines an aperture (not shown). Extending substantially 15 perpendicularly from first brake pad 307 is a connection portion 308, which also defines an aperture (not shown). To assemble first brake pad 307 onto first brake arm 302, a bolt 309 is inserted through the aperture defined by first brake arm 302 and the aperture defined by connection portion 308, and is then secured in position, by for example a nut (not shown). Thus, bolt 309 20 acts as a pivot for first brake pad 307.

Second brake arm 303 comprises a second brake pad 310. Second brake pad 310 is attached directly to the free end of second brake arm 303.

According to an alternative embodiment, second brake pad 310 is pivotally connected to second brake arm 303, as described above with reference to 25 first brake arm 302 and first brake pad 307. Preferably, both first brake pad 307 and second brake pad 310 have a corrugated surface contour 311.

Figure 3 also shows a spring 312, positioned around first brake arm 302.

Referring to Figure 2, positioning plates 209 are spaced apart sufficiently to allow the insertion of central brake arm 304 between them.

During assembly of safety clamp 112, a pivot bolt 210 is inserted sequentially 5 through the aperture (not shown) defined in a first positioning plate 207, through central aperture 306 defined in levered braking means 206 and through the aperture (not shown) defined in the second positioning plate 207.

Pivot bolt 210 is then secured in position, by for example a nut (not shown).

Thus, pivot bolt 210 functions to connect levered braking means 213 to first 0 collar section 201. In addition, pivot bolt 210 acts as a pivot for levered braking means 206.

As shown in Figure 2, levered braking means 206 is connected to and aligned with collar 201 such that first brake arm 302 extends to one side of central brake arm 304, and slots into brake arm slot 212 of brake arm housing 211 such that first brake pad 307 is located facing the aperture (not shown) defined in first collar section 201, and second brake arm 303 extends to the other side of central brake arm 304, such that second brake pad 310 is located outside the nearest perimeter of collar 201.

Thus, with levered braking means 206 assembled to collar 201 as 20 described above, spring 312, positioned around first brake arm 302, is located within brake arm housing 211. Spring 312 is placed in compression when placed inside brake arm housing 211. A first end of spring 312 applies a force against the front walling of brake arm housing 211 and the other end applies a force against first brake pad 307. With the levered arrangement of 25 braking means 213, which is pivoted about pivot bolt 210, first brake pad 307 is pushed into contact with scaffold pole 102 under the action of spring 312.

As previously described, preferably both first brake pad 307 and second brake pad 310 have a corrugated surface contour 311. This feature functions to allow water upon scaffold pole 102, to drain through the brake pad, thus preventing contact between the brake pad and the scaffold pole 102 from 5 being broken by the presence of water between them.

The vertical position of safety clamp 112 upon scaffold pole 102 is maintained by the action of spring 312. The degree of contact between first brake pad 307 and scaffold pole 102 under the force of the spring 312, however, allows safety clamp 112 to rotate around scaffold pole 102. Thus, if 10 a force applied to lanyard 110 causes lanyard 110 to change direction, for example when operative 107 moves from a first previous position to a second new position, safety clamp 112 can correspondingly rotate to align with the new direction of lanyard 110. This is advantageous in reducing cross-loading of lever handle 301 of levered braking means 213, in the event of a fall of operative 107.

Safety clamp 112 is configured such that safety clamp 112 will move up scaffold pole 102, in the direction of arrow 214, under a component of force applied to collar 201, in the direction of arrow 214. Similarly, safety clamp 112 is configured such that safety clamp 112 will move down scaffold 20 pole 102, in the direction of arrow 215, under a component of force applied to collar 201, in the direction of arrow 215. Thus, operative 107 can conveniently adjust the vertical positioning of safety clamp 112 upon scaffold pole 102 using a single hand.

Levered braking means 213 is configured such that when safety clamp 112 is in operation clamped around scaffold pole 102, levered braking means 213 is configured to activate under a force applied to lever handle 301

in either direction along the longitudinal axis of scaffold pole 102. Referring to Figure 3, with levered braking means 213 pivoted about central pivot aperture 306, a component of force applied to lever arm 301 in the direction of arrow 313 (anti-clockwise) will cause first brake arm 302, and thus first 5 brake pad 307, to advance in the direction of arrow 314 (anti-clockwise).

Similarly, a component of force applied to lever arm 301 in the direction of arrow 315 (clockwise) will cause second brake arm 303, and thus second brake pad 310, to advance in the direction of arrow 316 (clockwise). First brake pad 307 and second brake pad 310 each provide a braking contact 10 region. A braking contact region is a region which, when in contact with the support member upon which the safety clamp 112 is mounted, will provide a means of braking the safety clamp 112. Preferably, as shown in Figure 3, levered braking means 213 is a double brake, configured to provide more than one braking contact region.

Levered braking means 213 is configured to prevent the safety clamp 112 from travailing in either direction along the longitudinal axis of the scaffold pole 102, under a component of force applied to the lever handle 301. In the event that operative 107 falls from flat section 106 of scaffold To structure 101, the weight of operative 107 will pull lever handle 301 in the direction of arrow 313, causing first brake pad 307 to contact scaffold pole 102, to arrest the fall. Following a fall, operative 107 is supported by scaffold pole 102, which is a tubular, elongate member.

s Figure 4

Figure 4 shows operative 107 holding safety clamp 112 in the open configuration, with first collar section 202 opened apart from second collar section 203, in preparation for clamping safety clamp 112 around scaffold pole 102.

5 Safety clamp 112 is configured such that first collar section 202 and second collar section 203 can be held open apart from each other by means of hand grip 208. To hold safety clamp 112 in the open configuration, operative 107 has placed a hand 401 around levered braking means 213, such that a first digit 402 is positioned upon central arm 304 and a second o digit 403 is positioned around hand grip 208. Operative 107 is shown sustaining safety clamp 112 in the open configuration by applying a force upon hand grip 208, acting in the direction of arrow 404, by pulling hand grip 208 with second digit 403.

As previously described, first collar section 202 and second collar section 203 are configured to swing relative to each other about a spring loaded hinge 204. Hinge 204 comprises an internal hinge spring 405, having one end secured in a fixed position within first hinge shaft 205 and the other end secured in a fixed position within second hinge shaft 206. With this arrangement, spring 405 is prevented from rotating within hinge 204. Spring 20 405 is arranged within hinge 204 such that it is in the relaxed position when safety clamp 112 is in the closed configuration. Thus, the action of opening first collar section 202 open apart from second collar section 203 causes first hinge shaft 205 to move relative to second hinge shaft 206; causing spring 405 to twist. The action of opening safety clamp 112 transfers elastic energy as 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 202 and second collar section 203 together; to return spring 405 to the relaxed position. Thus, with safety clamp 112 in the open configuration, if operative 107 released the grip upon hand grip 208, spring 405 would act to close safety clamp 112. In this way safety 5 clamp 112 is self-acting towards the closed configuration, and is therefore self-closing. As shown in Figure 4, operative 107 is progressing safety clamp 112 in the direction of arrow 406, further around scaffold pole 102.

o Figure 5 Figure 5 shows a reverse angle of safety clamp 112 held in the same position as the position shown in Figure 4, and shows the components of automatic locking mechanism 207 in further detail. Hinge 204 is configured to close safety clamp 112 and automatic locking mechanism 207 is configured 15 to lock safety clamp 112 in the closed configuration. Thus, safety clamp 112 is self-locking.

Automatic locking mechanism 207 comprises a first hollow locking shaft 501 and a second hollow locking shaft 502 located longitudinally upon the outer surface of second collar section 203, adjacent the free edge 20 thereof. First locking shaft 501 is positioned near a first edge of collar 201 and defines a positioning aperture 503 in the outer end thereof. Similarly, second locking shaft 502 is positioned near the other edge of collar 201, and defines a positioning aperture 504 in the outer end thereof.

Automatic locking mechanism 207 includes a first release button 505, 25 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 5 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.

Automatic locking mechanism 207 further includes a second release 0 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 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 20 mounted relative to second locking shaft 502.

In addition, automatic locking mechanism 207 comprises a central hollow locking shaft 515 located longitudinally upon the outer surface of first collar section 202, adjacent the free edge thereof. Central locking shaft 515 defines a first pin aperture 516 at a first end thereof and a second pin 25 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 5 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 locking pin 520 are resiliently mounted relative to central locking shaft 515.

10 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. As shown in Figure 2, when safety clamp 112 is in the closed configuration, first locking shaft 501, second locking shaft 502 and central locking shaft 515 are in alignment with each other.

Figure 6 20 Figure 6 shows safety clamp 112 during a second subsequent stage of clamping around scaffold pole 102, in which safety clamp 112 is in the process of self-locking first collar section 202 and second collar section 203 together, in the closed configuration. Safety clamp 112 is configured such that as safety clamp 112 self closes, safety clamp 112 self locks.

25 Operative 107 has advanced safety clamp 112 further in the direction of arrow 406 to locate safety clamp 112 around scaffold pole 102 and, once

the free end of first collar section 202 and second collar section 203 have advanced past the diameter of scaffold pole 102, has released hand grip 208 to allow safety clamp 112 to self close around scaffold pole 102 under the action of hinge spring 405.

5 Under the action of hinge spring 405, first collar section 202 advances in the direction of arrow 601, towards second collar section 203, and second collar section 203 advances in the direction of arrow 602, towards first collar section 202. As shown in Figure 6, first locking pin 519 comes into contact with first locking shaft 501. Similarly, second locking pin 520 comes into 10 contact with second locking shaft 502. First collar section 202 and second collar section 203 are able to advance into the closed configuration, and simultaneously into a locked configuration, as described below.

As first collar section 202 and second collar section 203 advance towards each other, under the action of hinge spring 405, first locking shaft 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, To 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 as 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 112 during a third subsequent stage of 5 clamping around scaffold pole 102, in which the safety clamp 112 has self closed and simultaneously self locked around scaffold pole 102.

As previously described, during the second stage of safety clamp 112 clamping around scaffold pole 102, first locking pin 519 and second locking pin 520 are pushed inwards into central locking shaft 515, compressing pin to 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, s through first pin aperture 516 such that first locking pin 519 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 so and second locking pin 520 entering first locking shaft 501 and second locking shaft 502 respectively, locks safety clamp 112 in the closed configuration. Safety clamp 112 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 112 configured to be self-locking, the safety clamp 112 being configured to be clamped around a support member by the method of applying force to the

safety clamp 112 to sustain safety clamp 112 in an open configuration, locating the safety clamp 112 around a support member, and removing the force to reconfigure the safety clamp from the open configuration to the closed configuration.

5 It can be seen from Figure 7, that in the locked configuration of safety clamp 112, the position of first locking pin 519 relative to first locking shah 501, and the position of second locking pin 520 relative to second locking shaft 502, prevent first collar section 202 and second collar section 203 from opening apart from each other. It can further be seen from Figure 7 that, in 0 the locked configuration of safety clamp 112, 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 15 Figure 8 shows operative 107 executing a first stage of unclamping safety clamp 112 from around scaffold pole 102. Operative 107 has placed a hand 801 around automatic locking mechanism, 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.

20 Operative 107 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 107 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 25 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 107 continues to depress first release button 505 and second release button 510, safety clamp 112 is reconfigured into a release configuration, which is illustrated in Figure 9.

5 Figure 9 As shown in Figure 9, in the release configuration, first release 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 10 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.

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 describedabove, first collar section 202 can be opened apart from second collar section 203, as shown in Figure 10.

Figure 10 As previously described, hinge 204 is spring loaded, such that hinge 204 acts to close first collar section 202 and second collar section 203 together, under the action of hinge spring 405, which is in the relaxed position 25 when safety clamp 112 is in the locked configuration. Thus, to open safety clamp 112, a positive force acting to configure hinge spring 405 into the

me energised position is required. To achieve this, operative 107 has placed hand 401 around levered braking means 213, such that a first digit 402 is positioned upon central arm 304 and a second digit 403 is positioned around hand grip 208. Operative 107 is shown sustaining safety clamp 112 in the open configuration by applying a force upon hand grip 208, acting in the direction of arrow 1001, by pulling hand grip 208 with second digit 403. This technique of sustaining safety clamp 112 in the open configuration to unclamp safety clamp 112 from around scaffold pole 102 is similar to the technique of sustaining safety clamp 112 in the open configuration in 10 preparation for clamping safety clamp 112 around scaffold pole 102, as described with reference to Figure 4. After first collar section 202 and second collar section 203 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, 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 112 from around scaffold pole 102, operative 107 holds safety clamp 20 112 in the open configuration whilst moving safety clamp 112, in the direction of arrow 1001, away from the scaffold pole 102.

Thus, the present invention provides a safety clamp 112 configured to self lock in a closed configuration, the safety clamp 112 being configured to be clamped around a support member by the method of reconfiguring the z safety clamp 112 from a closed configuration to an open configuration, locating the safety clamp 112 around a support member, and reconfiguring

the safety clamp from the open configuration to the closed configuration.

Following the removal of safety clamp 112 from scaffold pole 102, operative 107 can release his grip on hand grip 208, and safety clamp will self-lock in the closed configuration, as described above. Thus, when safety 5 clamp 112 is in the closed configuration, safety clamp 112 is in the locked configuration. According to an alternative embodiment of the present invention, safety clamp 112 comprises a fall arrest webbing (not shown) connected to lever handle 301. To assemble the webbing to safety clamp 112, a first end 10 of the webbing is passed through connection aperture 305, doubled back upon itself and stitched together. The other end of the webbing can be connected to safety harness 109 worn by operative 107, by means of a karabiner, such as karabiner 111. The webbing comprises a rip stitch energy absorbing length, which is preferably concertinaed and stitched into a protective cover. The stitching is configured to break in the event of a fall of operative 107, to release the energy absorbing length. This action functions to reduce the fall arrest forces, and to control the deceleration distance.

Safety clamp 112 is suitable for use in a fall restraint system. Fall restraint systems are configured to prevent operatives from falling. Referring 20 to Figure 1, which illustrates a fall arrest system, operative 107 is able to reach at least one edge of flat section 106 of scaffold structure 101.

According to a fall restraint system, operative 107 would not be able to reach an edge of flat section 106. Thus, the risk of operative 107 falling from flat section 106 is reduced. A way of achieving such a system is to reduce the 25 length of lanyard 110, which extends between safety clamp 112 and operative 107. Alternatively, if a fall restraint lanyard is used, which has a

plurality of connection points along the length thereof, operative 107 could connect to a connection point closer to the safety clamp 112, thus reducing the effective length of the fall restraint lanyard. In addition, there is an inverse relationship between the height at which safety clamp 112 is located upon a scaffold pole 102, relative to the level of flat section 106 upon which operative 107 is standing, and the distance operative 107 can walk upon flat section 106 from the scaffold pole 102. Furthermore, with a fixed length lanyard 110, the distance that operative 107 could fall from flat section 106 is reduced as the height of safety clamp 112 upon scaffold pole 102 is increased. Thus, 10 increasing the height of safety clamp 112 relative to operative 107 can increase the level of safety provided by using safety clamp 112 within a fall arrest or a fall restraint system.

Referring to Figure 1, operative 107 is shown connected to a single safety clamp 112, which is located upon scaffold pole 102. However, operative 107 is preferably working within a personal safety system comprising a second safety clamp according to the above described preferred embodiment of the present invention. The second safety clamp provides a second safety connection for operative 107. In the event that operative 107 is required to relocate the safety connection from scaffold pole 20 102 to scaffold pole 103, for example in the event that operative 107 is required to traverse along flat section 106 of scaffold structure 101, the second safety clamp provides a method of safely relocating the safety connection. A preferred method is described below, with reference to Figure 25 Figure 1 shows operative 107 already connected to safety clamp 112, which is clamped around a first scaffold pole 102. With this arrangement,

safety clamp 112 provides a first safety connection for operative 107 upon scaffold pole 102. Connected to the safety harness 109, worn by operative 107, is a second safety clamp 112 according to the present invention(not shown). 5 To relocate the safety connection, operative 107, whilst remaining connected to first safety clamp 112 clamped around first scaffold pole 102, clamps the second safety clamp to a second scaffold pole 103. Following completion of this operation, the second safety clamp provides a second safety connection, thus operative 107 is provided with two safety to connections. To complete the relocation of the safety connection, operative 107 unclamps first safety clamp 112 from first scaffold pole 102, to remove the first safety connection. Following this operation, second safety clamp provides operative 107 with a safety connection upon scaffold pole 103.

Thus, by following the above described method, operative 107 can relocate a 15 safety connection from a first scaffold pole 102 to a second scaffold pole 103 safely, at least one safety connection being provided during each operation constituting the method. Using such a method, operative 107 can safely traverse along a structure such as scaffold structure 101.

Claims

1. A safety clamp for use within a fall arrest system in which said clamp in operation is clamped around an elongate support member, wherein said clamp is configured to self-lock around said support member.

2. A safety clamp according to claim 1, wherein said safety clamp is releasably self-locking.

3. A safety clamp according to claim 1 or claim 2, wherein said safety clamp comprises a first collar section and a second collar section configured to swing relative to each other about a spring loaded hinge, said hinge configured to self close the first collar section and the second collar section together in a closed configuration.

4. A safety clamp according to claim 3, wherein said safety clamp comprises an automatic locking mechanism configured to lock said first collar section and said second collar section together in the closed configuration.

5. A safety clamp according to claim 4, wherein said automatic locking mechanism comprises first and second locking shafts located upon said second collar section, a central locking shaft located upon said first collar section, and spring loaded first and second locking pins located within said s central locking shaft, wherein said first and second locking shafts are configured to receive one of said first and second pins.

6. A safety clamp according to claim 5, wherein said automatic locking mechanism further comprises a first release button configured to move relative to said first locking shaft and a second release button 5 configured to move relative to said second locking shaft, said first release button configured to release said first locking pin from said first locking shaft and said second release button configured to release said second locking pin from said second locking shaft.

to

7. A safety clamp according to claim 6, wherein said first and second locking pins have a tapered surface.

8. A safety clamp according to any preceding claim comprising levered braking means configured to activate under a force applied to the lever in either direction along the longitudinal axis of the support member.

9. A safety clamp according to claim 8, wherein said levered braking means is a double brake.

20

10. A safety clamp according to claim 9, wherein said safety clamp comprises a collar, said double brake comprises a central brake arm disposed between a first brake arm and a second brake arm, and said central brake arm is pivotally connected to said collar.

25

11. A safety clamp according to claim 10, wherein said first brake arm comprises a first brake contact region at the free end thereof, and said

second brake arm comprises a second brake pad at the free end thereof.

12. A safety clamp according to claim 11, wherein at least one of said first and second brake pads is pivotally connected to a brake arm.

13. A safety clamp according to claim 11 or claim 12, comprising resilient means configured to provide, in operation, a degree of contact between one of said first and second brake pads and said elongate support member.

14. A safety clamp according to any of claims 11 to 13, wherein at least one of said first and second brake pads has a corrugated contour.

15. A safety clamp according to any of claims 8 to 14, wherein said 15 levered braking means defines a connection aperture.

16. A safety clamp according to any of claims 8 to 14, dependent upon any of claims 4 to 7, wherein said levered braking means is located opposite said automatic locking mechanism.

17. A method of clamping a safety clamp around a support member, wherein said safety clamp is configured to self-lock in a closed configuration, comprising the steps of reconfiguring the safety clamp from the closed configuration to an 25 open configuration;

locating the safety clamp around a support member; and reconfiguring the safety clamp from the open configuration to the closed configuration.

5

18. A method of clamping a safety clamp around a support member according to claim 17, comprising the steps of applying force to said safety clamp to sustain the safety clamp in an open configuration; locating the safety clamp around a support member; and 0 removing said force to reconfigure the safety clamp from the open configuration to the closed configuration.

19. A method of relocating a safety connection comprising the steps of 5 clamping a first self-locking safety clamp around a first support member to provide a first safety connection; clamping a second self- locking safety clamp around a second support member to provide a second safety connection; and unclamping said first self-locking safety clamp from around said first 20 support member to remove said first safety connection.

20. A self-locking safety clamp substantially as herein described with reference to and as shown in Figures 1 to 10.

21. A method of clamping a self-locking safety clamp around a support member substantially as herein described with reference to and as

shown in Figures 1 to 10.

22. A method of relocating a safety connection, using first and second self-locking safety clamps, substantially as herein described with 5 reference to and as shown in Figures 1 to 10.