GB2594140A

GB2594140A - Improvements in and relating to safety systems

Info

Publication number: GB2594140A
Application number: GB2102120.9A
Authority: GB
Inventors: Gould Tony
Original assignee: VP PLC
Current assignee: VP PLC
Priority date: 2020-02-13
Filing date: 2021-02-15
Publication date: 2021-10-20
Also published as: GB202001982D0; GB202102120D0

Abstract

The system comprises a restraint 29 and a strut 5,3. The restraint has a first 33a and second 33b part which make up a body. The first and second parts define part or all of a perimeter and have an end and inner and outer surfaces with a number of projections or ribs with at least one on the inner surface of each first and second part. The restraint can be open or closed where when opened there is a gap between the ends of the first and second parts. The strut 5,3 has an exterior surface which comprises locations on which to mount the restraint provided by annular grooves. The body may have a pivotal mount for the first and/or second parts and the first and second parts may have two parts of a releasable fastener. There may be more than one projection on each part spaced apart by between 2 an 12cm. The strut may be an internal or external strut and each of the mounting locations may be a separate groove. The support system my comprise strut elements where one slides within the other. A method of providing support using an expandable or telescoping support system is also claimed.

Description

IMPROVEMENTS IN AND RELATING TO SAFETY SYSTEMS

This invention concerns improvements in and relating to safety systems, particularly, but not exclusively, in relation to safety systems for expandable support systems such as struts.

In a wide variety of situations, expandable support systems, such as struts, are used to maintain the position of other structures, for instance shoring in excavations. To function in this way the expandable support system needs to have a first reduced length state and a second extended length state. The support function of the expandable support system is provided in the second extended length state. Such systems are frequently hydraulically operated and the hydraulics are often used to maintain the expandable support system in the second state. In the event of a failure within the system, there is a chance of a movement of the expandable support system from the second state towards the first state. This can cause loss of support from the expandable support system and/or movement of the expandable support system itself. Both of these present safety issues.

The present invention has amongst its potential aims to provide an improved safety system for such expandable support systems. The present invention has amongst its potential aims to provide a mechanical limit on the movement of the expandable support system in the event of a failure.

According to a first aspect of the invention there is provided a safety system, the safety system comprising: a restraint; and a strut element; wherein the restraint comprises: a body, the body including a first part and a second part, both the first part and the second part having an outer surface and an inner surface, the first part and the second part defining at least a part of the perimeter around a space, the first part having an end and the second part having an end; a plurality of projection elements; wherein at least one projection element is provided on the inner surface of the first part and at least one projection element is provided on the inner surface of the second part; wherein the restraint has an open state and a closed state, the open state providing a gap between the end of the first part and the end of the second part, the closed state providing a reduced gap between end of the first part and the end of the second part; and.

wherein the strut element comprises an external surface, the external surface having an exterior section, the exterior section being provided with one or more mounting locations for a restraint.

The restraint may include any of the features, options and possibilities provided for the restraint elsewhere in this document, particularly in the second aspect of the invention.

The strut element and/or the one or more mounting location may include any of the features, options and possibilities provided therefore elsewhere in this document, particularly in the third aspect of the invention.

According to a second aspect of the invention there is provided a restraint, the restraint comprising: a body, the body including a first part and a second part, both the first part and the second part having an outer surface and an inner surface, the first part and the second part defining at least a part of the perimeter around a space, the first part having an end and the second part having an end; a plurality of projection elements; wherein at least one projection element is provided on the inner surface of the first part 30 and at least one projection element is provided on the inner surface of the second part; wherein the restraint has an open state and a closed state, the open state providing a gap between the end of the first part and the end of the second part, the closed state providing a reduced gap between end of the first part and the end of the second part.

The body may comprise a mounting element, such as a head block. The mounting element may be provided at the top of the restraint, in use.

The mounting block may provide a lifting point for the restraint. The lifting point may include a through aperture. The through aperture may be defined by a pair of projections 10 from the mounting element and a bar extending between that pair of projections.

The mounting element may provide a mounting for the first part and the second part. The mounting may provide freedom of movement for the first part and the second to move between the open state and the closed state and/or vice versa. Preferably movement in a plane perpendicular to the long axis and/or longitudinal axis of the restrain and/or, in use, the expandable support system is provided.

The mounting element may provide a pivotal mounting for the first part and/or the second part. The pivotal mounting may be provided by an elongate element, such as a pin, extending parallel to the long or longitudinal axis of the restraint, potentially in combination with a pair of opposing plates and an aperture through the pair of opposing plates to receive the elongate element. Both pivotal mountings may be provided in this manner. The first part may be provided, preferably at the top, with an element through which the elongate element passes. The second part may be provided, preferably at the top, with an element through which the elongate element passes.

The first part, preferably proximal the end of the first part, may be provided with part of a releasable fastener assembly. The second part, preferably proximal the end of the second part, may be provided with a further part of the releasable fastener assembly.

The part of the releasable fastener assembly and/or second part of the releasable fastener assembly may be a stem extending from the first part and/or second part respectively. The part of the releasable fastener assembly and/or second part of the releasable fastener assembly, preferably as a stem, may be provided with a through aperture, preferably lying on a common axis. The releasable fastener may include a bolt tightened and/or untightened in the releasable fastener assembly. A bolt may be held in position by a nut.

The part of the releasable fastener assembly and/or second part of the releasable fastener assembly may be and/or may be in a fastener block. The fastener block may be in two sections, for instance with a first section provided on the first part and a second section provided on the second part. An aperture may be provided in the first section and/or second section. One or more of the apertures may be provided as a through aperture, preferably lying on a common axis. The releasable fastener may include a bolt tightened and/or untightened into the first and/or second section. A bolt may be held in position by a nut and/or by engagement with the first section and/or second section.

The first part of the restraint and the second part of the restraint may be mirror images of each other.

A top split between the first part and the second part may be provided, preferably proximal the mounting element. The top split is preferably provided between the rotational axis for the first part and the rotational axis for the second part.

A bottom split between the first part and the second part may be provided, preferably proximal the releasable fastener assembly. The bottom split is preferably provided between the two stems and/or two sections.

The first part of the restrain and/or the second part of the restrain may each extend around one half of the perimeter of the space, potentially +/-10%, preferably +/-5%, of 30 the length of the perimeter. The perimeter may be a circle. The diameter of the circle may be greater than 30cm, potentially greater than 40cm, preferably greater than 50cm. The diameter of the circle may be less than 500cm.

The space may be a cylindrical space, preferably a right cylinder, most preferably with a long and/or longitudinal axis aligned with the axis of the expandable support system in use.

The inner surface of the first part and/or second part may be mirror images of one another. The inner surface may be annular. The diameter of the annulus may be greater 10 than 30cm, potentially greater than 40cm, preferably greater than 50cm. The diameter of the circle may be less than 500cm.

The inner surface of the first part and/or second part may be provided with two or more, preferably a pair of, projection elements. The two or more projection elements may be spaced from one another, preferably along the long and/or longitudinal axis of the restraint and/or, in use, the expandable support element. The projection proximal to one end of the restraint may be provided closer to the end of the restraint that the projection proximal to the other end of the restraint is to that other end of the restraint Two or more projection elements may be axially offset within the restraint.

One or more or all of the projection elements may be welded to the first part and/or second part.

Preferably the projection elements on the first part extend over 70% of the length of the inner surface of the first part, preferably over 80%, more preferably over 90% and ideally over 95%. Preferably the projection elements on the second part extend over 70% of the length of the inner surface of the first part, preferably over 80%, more preferably over 90% and ideally over 95%.

Preferably a projection element on a first part in combination with a projection element on a second part forms an annular projection.

Preferably a projection element on a first part is provided in the same plane as a projection element on the second part, most preferably relative to a plane which is perpendicular to the long and/or longitudinal axis of the restrain and/or, in use, the expandable support system. Preferably each projection element on a first part is coplanar with a projection element on a second part.

The spacing of the projection elements along the axis may be greater than 2cm, preferably greater than 3cm and ideally greater than 5cm, between the start of one projection element and the start of the next. The spacing may be less than 12cm, preferably less than 10cm and ideally less than 8cm between the start of one projection element and the start of the next projection element.

One or more or all of the projection elements may have a height, extending into the space, greater than 0.5cm relative to the inner surface of the part, preferably greater than 0.8cm and ideally 1cm or greater, One or more or all of the projection elements may have a width of greater than 5cm, preferably greater than 8cm and potentially greater than 13cm.

Preferably the projection element on the first part is split from a projection part on the second part at the same location or locations as the first part is split from the second part.

The outer surface of the first part and/or the outer surface of the second part may be provided with one or more handles. Preferably the handles are provided in matching locations. Preferably the first part is provided with a handle and the second part is provided with a handle.

The open state for the restraint may provide a minimum gap between the end of the first part and the end of the second part of greater than 30cm, potentially greater than 40cm, preferably greater than 50cm. The minimum gap may be less than 500cm.

The closed state for the restraint may provide a maximum gap between the end of the first part and the end of the second part of less than 3cm, potentially less than 2cm, preferably less than lcm and ideally less than 0.5cm.

The restraint may be held in the closed state by the presence of one or more releasable 10 fasteners.

According to a third aspect of the invention there is provided a strut element, the strut element comprising an external surface, the external surface having an exterior section, 15 the exterior section being provided with one or more mounting locations for a restraint.

The strut element may be an internal strut element. The internal strut element may be received within an external strut element.

The strut element may be an external strut element. The external strut element may receive an internal strut element. The internal strut element may be slidably received.

The strut element may have an end bearing plate. The end bearing plate may be pivotally mounted or hinged. Preferably the end bearing plate contacts, in use, one or more places 25 where support is required. The one or more places may be one or more structural elements, for instance a wall and/or shoring.

One or more or all of the mounting locations may be provided with one or more or all of the following features, options or possibilities.

A mounting location may have an extent around a part of the periphery of the strut element. A mounting location may have an extent which lies on a common plane and/or extends around a pad of the periphery of the strut element. The common plane may be a plane perpendicular to the long or longitudinal axis of the strut element, +/-10°, or +/-5°, or +/-3°, or +/-1° or truly perpendicular.

A plurality of mounting locations may be provided. The plurality of mounting locations may be provided spaced along the long and/or longitudinal axis of the strut element. The spacing of the mounting locations along the axis may be the same between each pair of adjoining mounting locations. The plurality of mounting locations may be provided each on a series of common planes spaced along the long and/or longitudinal axis of the strut element. Each of the common planes may be a plane perpendicular to the long or longitudinal axis of the strut element, +/-10°, or +/-5°, or +/-3°, or +/-1° or truly perpendicular. The spacing of the common planes may be the same between adjoining common planes. The spacing may be greater than 2cm, preferably greater than 3cm and ideally greater than 5cm, between the start of one mounting location and the start of the next. The spacing may be less than 12cm, preferably less than 10cm and ideally less than 8cm between the start clone mounting location and the start of the next mounting location.

At least 5 mounting locations are provided at different extents along the long and/or longitudinal axis, preferably at least 8 mounting locations, more preferably at least 12 mounting locations and ideally at least 15 mounting locations.

One or more or preferably all of the mounting locations are provided within an exterior section of the strut element. The exterior section is preferably proximal to another strut element, in use, but not covered by that another strut element in use.

The exterior section may extend at least 50cm along the strut element, preferably at least 30 80cm, more preferably at least 100cm. The exterior section may extend between the mounting location closest to one end of the strut element and the mounting location closest to the other end of the strut element.

A mounting location may be a recess in the exterior section of the strut element.

Preferably the mounting location is all recessed within the external profile of the strut element. Preferably no part of the mounting location extends beyond the external profile of the strut element. The external profile of the strut element may be the external profile which is received within another strut element.

A mounting location may be provided by one or more mounting location parts. Where a plurality of mounting location parts are provided, they may be provided spaced around the mounting location. The spacing may be regular. The mounting location may extend around the full periphery of the strut element, for instance as continuous channel or groove.

A mounting location may be a groove. Preferably a mounting location is formed of a single groove, most preferably a single continuous groove extending around the full periphery of the strut element. Each of the mounting locations may be a separate groove spaced along the strut element. One or more helical grooves are a possibility for the mounting location.

A mounting location may include an abutment surface. Preferably the abutment surface is perpendicular to the long and/or longitudinal axis of the strut element, +/-10°, or +/-5°, or or +/-1°, or truly perpendicular. The mounting location may include a base surface.

Preferably the base surface is parallel to the long and/or longitudinal axis of the strut element, +/-10°, or +/-5°, or +/-3°, or +/-1° or truly parallel. A mounting location may include an inclined surface relative to the long and/or longitudinal axis of the strut element, for instance an incline of 70°, +/-10°, or +FS°, or +/-3°, or +/-1° or at that incline. Preferably the abutment surface is provided distal the another strut element, in use.

Preferably the inclined surface is provided proximal the another strut element, in use.

Preferably the base surface is provided intermediate the abutment surface and the inclined surface.

A mounting location may have a depth greater than 0.5cm relative to the external profile 5 of the strut element, preferably greater than 0.8cm and ideally 1cm or greater. The mounting location may have a width of greater than 5cm, preferably greater than 8cm and potentially greater than 13cm.

According to a fourth aspect of the invention there is provided an expandable support system, the expandable support system comprising: a first strut element; and a second strut element; wherein a part of one of the strut elements is slideably received within the other of the 15 strut elements, the expandable support system having a first reduced length state and a second increased length state; wherein at least one of the strut elements comprises an external surface, the external surface having an exterior section, the exterior section being provided with one or more mounting locations for a restraint.

The at least one of the strut elements may further comprise one or more or all of the features, options and possibilities provided for the strut element provided elsewhere in this document, including in the third aspect of the invention.

The second strut element preferably receives a part of the first strut element within it. The part is variable so as to vary the expandable support system between the first reduced length state and the second increased length state and vice versa.

Preferably both the first strut element and the second strut element are provided with an 30 end bearing plate. The end bearing plates may be pivotally mounted or hinged. Preferably the end bearing plates contact, in use, one or more places where support is required. The one or more places may be one or more structural elements, for instance a wall and/or shoring.

The second strut element may provide a receiving end, at the location where the part of the first strut element is received within the second strut element. The receiving end may provide an abutment surface for the restraint, particularly in the event of transition of the expandable support system from the second increased length state towards the first reduced length state when the restraint is provided on the expandable support system in the closed state. An annular plate may be provided at the receiving end to provide the abutment surface.

Preferably at least two mounting locations are accessible outside of the second strut element in the second increased length state.

According to a fifth aspect of the invention there is provided a method of providing a safety system on an expandable support system, the method including: providing a restraint adjacent the expandable support system; lifting the restraint onto the expandable support system; and then placing the restraint in a closed state around a strut element of the expandable support system to form the safety system.

The expandable support system may include any of the features, options and possibilities 25 provided for the expandable support system elsewhere in this document, particularly in the fourth aspect of the invention.

The strut element may be provided with one or more mounting locations. The restrain may be provided with one or more projection elements. Preferably in the closed state, a projection element on the restraint engages with a mounting location on the strut element. The closed state may be maintained by a releasable fastener.

The safety system may include any of the features, options and possibilities provided for the safety system elsewhere in this document, particularly in the first aspect of the invention.

The method may further include engaging a lifting device with a lifting location on the restraint.

The method may further include removing and/or releasing a releasable fastener provided for the restraint.

The method may further include lifting the restraint above the first strut element.

The method may further include placing the restraint in an open state, for instance by increasing the gap between an end of a first part and an end of a second part of the restraint.

The method may further include lowering the restraint with a strut element, preferably the first strut element, passing through the gap in the restraint, for instance the gap between an end of a first part and an end of a second part of the restraint. The method may include positioning the strut element, preferably the first strut element, within the space of the restraint.

The method may include positioning the restraint around the first strut element adjacent a second strut element, preferably adjacent the receiving end of the second strut element, for instance where the first strut element enters the second strut element. A gap may be provided between the receiving end of the second strut element and the proximal part of the restraint, for instance an abutment surface of the restraint, such as a side wall of the restraint. The gap may be less than 50cm, preferably less than 35cm and ideally less than 25cm. The gap may be more than 5cm, preferably more 8cm and ideally more than 10cm.

The method may include rotating the restraint relative to the expandable support system to select the value for the gap, before the restraint is lowered on to the expandable support system.

The method may include positioning projection elements of the restraint aligned with the first mounting location exposed on the first strut element at the receiving location.

Preferably the first projection element is aligned with the first mounting location and the second projection element is aligned with the second mounting location.

Preferably the transition from the open state to the closed state introduces a projection element to a mounting location. Preferably all projection elements are introduced to a mounting location. One or more of the projection elements may be guided into the mounting locations by a guide surface, for instance an inclined guide surface. Preferably the transition from the open state to the closed state places part of a projection element, ideally of all projection elements, in contact with a base of the mounting locations.

Preferably the transition from the open state to the closed state places part of a projection element, ideally of all projection elements, in proximity with or abutment with an abutment surface of the mounting locations.

The method may further include reintroducing and/or fastening a releasable fastener 30 provided for the restraint.

The closed state for the restraint preferably provides a third restrained state for the expandable support system.

The closed state and/or third restrained state preferably limit movement of the first strut element and the second strut element relative to one another. The closed state and/or third restrained state preferably limit movement of the first strut element and the second strut element relative to one another due to abutment of a part of the restraint upon the receiving end of the second strut element if there is movement.

The closed state and/or third restrained state preferably limit movement of the first strut element and the second strut element relative to one another to less than 50cm, preferably less than 35cm and ideally less than 25cm. The closed state and/or third restrained state preferably allow movement of the first strut element and the second strut element relative to one another by more than 5cm, preferably by more 8cm and ideally by more than 10cm.

According to a sixth aspect of the invention there is provided a method of supporting a 20 location, the method comprising: introducing an expandable support system into a location; providing the expandable support system in a supporting state in the location; then providing a safety system on an expandable support system, by: providing a restraint adjacent the expandable support system; lifting the restraint onto the expandable support system; and then placing the restraint in a closed state around a strut element of the expandable support system to form the safety system.

The expandable support system may include any of the features, options and possibilities provided for the expandable support system elsewhere in this document, particularly in the fourth aspect of the invention.

The method may include lifting the expandable support system into a location for use. The method may include providing the expandable support system at the location in the first reduced length state.

The method may include transitioning the expandable support system to a second increased length state, preferably from the first reduced length state. The transition may be provided by the application of mechanical force and/or hydraulic force to the expandable support system.

The expandable support system may be provided in the supporting state by transition to a second increased length state. The second increased length state may continue until there is contact between the expandable support system and one or more structural elements to be supported, more preferably until the expandable support system provides the desired load to the one or more structural elements. Preferably an end bearing plate provided on the expandable support system contacts, in use, one or more places where support is required. The one or more places may be one or more structural elements, for instance a wall and/or shoring.

The transition from the first reduced length state to the second increased length state may expose part or all of the exterior section of the strut element, for instance as that part of the strut element is no longer within another strut element. The method may include providing the safety system in a cooperating engagement with a part of the exterior section.

The method may include providing the safety system on the expanded support system by any of the features, options or possibilities provided by this document, particularly the fifth aspect of the invention.

The method may include providing the safety system in the closed state by by any of the features, options or possibilities provided by this document, particularly the fifth aspect of the invention.

The method may further include removal of the expandable support system from the location. The method may further include placing the restraint in an open state. The method may further include removing the restraint from the expandable support system. The method may include returning the expandable support system at the location to the first reduced length state. The method may include transitioning the expandable support system from a second increased length state towards the first reduced length state. The transition may be provided by the removal and/or application of mechanical force and/or hydraulic force to the expandable support system. The method may include lifting the expandable support system out of the location.

According to a seventh aspect of the invention there is provided a method of modifying a 30 strut element, the method comprising: obtaining a strut element, the strut element having been used to provide support for a structural element; forming one or more mounting locations for a restraint in an exterior section of an external surface of the strut element; incorporating the modified strut element into an expandable support system.

The method may further include retro-fitting the one or more mounting location to the strut element.

The method may further include removing the strut element from an expandable support system prior to forming the one or more mounting locations.

The strut element is preferably an internal strut element that is slideably received within an external strut element.

The method may include forming the one or more mounting locations to have any of the features, options or possibilities for the mounting locations and/or strut element defined in the third aspect of the invention.

The method may include incorporating the modified strut element into an expandable support system having any of the features, options or possibilities for the expandable support system defined in the fourth aspect of the invention.

The method may include using the modified strut element in a method according to any of the features, options or possibilities of the fifth and/or sixth aspects of the invention.

Various embodiments of the invention will now be described, by way of example only and with reference to the accompanying drawings in which: Figure 1 is an illustration of a prior art expandable support system in use; Figure 2a is a side view of an internal strut element provided with the first pad of a safety system according to the invention; Figure 2b is a detail of the cross-sectional profile of the groove of the first part of the safety system of Figure 2a; Figure 3a is a front view of a second part of a safety system according to an embodiment 10 of the invention; Figure 3b is a side view of the second part of the safety system of Figure 3a; Figure 4 is a perspective view of an expandable support element to which the safety system is being applied; Figure 5 is an illustration of the safety system in position on an expandable support system; Figure 6 is a side view of an expandable support system with the safety system of the invention deployed.

A wide variety of expandable support systems are known and these include strut units, braces and props. The expandable support systems are often used for propping up structural elements, such as side walls, shorings, slabs and temporary roof structures amongst other examples.

In use, the expandable support system is introduced into the location, where support is required, in a first, reduced, length state and then is transitioned to a second, increased, length state in which the support ends of the expandable support system contact the structural elements to be supported.

Figure 1 provides an illustration of such a use, wherein the expandable support system 1 is formed of an internal strut element 3 slideably received within an external strut element 5. The internal strut element 3 carries an end bearing plate 7. This may be hinged or otherwise pivotally mounted to enable the ends to articulate to desired extent. A similar end plate 7 is provided at the other end on the external strut element 5.

The expandable support system 1 is lifted into position in the first, reduced, length state and then expanded towards the second, increased, length state mechanically or using hydraulics. This brings the end bearing plates 7 into contact with the structural elements 9 to be supported and appropriate force can be applied to maintain the structural supports 9 in position and to maintain the position of the expandable support system 1 thereon.

A wide range of expandable support systems exist to span different lengths and to handle different loads in those situations, amongst other variables accommodated. The larger the load, the larger the expandable support system 1 becomes and as a consequence the more material the danger is from any failure in the expandable support system 1. One such risk is of the expandable support system 1 attempt an undesirable transition from the second expanded length state towards a first reduced length state. This can cause the expandable support system 1 to fall within the location it is being used in and/or cause the structural elements to give way.

As the size loads provided by and hence acting on the expandable support element 1 increases, therefore, the provision of a safety system to prevent or minimise inadvertent transitioning from the second expanded length state towards the first reduced length state is beneficial.

The present invention offers a safety system which is suitable for provision on new expandable support systems 1 and/or for retrofitting to existing expandable support systems 1.

As shown in Figure 2a, a first part of the safety system is provided. An internal strut element 3 is provided with a series of mounting locations 10. These are not provided by a helical groove, but rather a series of annular grooves 13 in a series of planes, X-X, provided perpendicular to the long axis 11 of the expandable support system 1. The mounting locations 10 are provided along an exterior section 15 of the internal strut element 3. The exterior section 15 is proximal to, but extends away from the external strut element 5, when the internal strut element 3 and the external strut element 5 are in their anticipated use state, the second, increased, length state. Thus the annular grooves 13 are provided in the exterior section 15 of the internal strut element 3 that is distal the end bearing plate (not shown) of the internal strut element 3.

In the embodiment shown, the annular grooves 13 extend around the entire periphery of the internal strut element 3 and are spaced at regular intervals along the length of the exterior section 15 of the internal strut element 3. As an example only, the annular grooves 13 are provided with a 60mm pitch and are provided over a 1.5m length of the internal strut element 3.

Referring to Figure 2b, a detailed cross section of the annular groove 13 is shown. This is defined by the unaltered external profile 17 of the internal strut element 3 left and right of the annular groove 13. Moving from the distal end of the internal strut element 3 relative to the external strut element 5, there is a rounded corner 19 leading to an abutment surface 21 which is perpendicular to the long axis 11 A rounding 23 leads to the base 25 of the annular groove 13, with the base 25 provided parallel to the long axis 11. A guide surface 27 follows which is inclined and leads from the base 25 up to the unaltered external profile 17. The guide surface 27 is provide at an angle of 70° to the long axis 11 in this example. The groove has a depth of 10mm, unaltered external profile 17 to base 25, and the base 25 has a length of 13.5mm in this example. The function of the different parts of the groove detail will be described later in this document.

The second part of the safety system for the expandable support system 1 is shown in Figure 3a. The second part is provided by a restraint 29. As shown in Figure 3a, this is viewed looking along the long axis 11 of the expandable support system 1. In Figure 3b it is viewed looking perpendicular to that long axis 11.

The restraint 29 is formed of an annular element 31 which is split into two parts 33a and 33b. The two parts 33a, 33b, are of equal proportions and are split at the base split 35 and at the head split 37, where they are also pivotally mounted in a head block 39 by means of pivots 41a and 41b. The head block 39 includes not only the pivots 41a and 41b, but also a lifting location 43 for the restraint 29.

Proximal to the base split 35 each of the parts 33a and 33b are provided with a projection 45a and 45b, with each projection 45a, 45b, being provided with an aperture 47a, 47b, lying on the same axis so as to allow a bolt 49 to be introduced, a nut 51 applied and tightened to maintain the two parts 33a and 33b in the closed, use, position of Figures 3a and 3b.

Inside the parts 33a, 33b, are a pair of projection elements 53a, 53b, with only the first projection element 53a visible in Figure 3a. Both the first projection element 53a and second projection element 536 are visible in Figure 3b. In the format shown these are both hoops, broken at the base split 35 and head split 37, which are welded to the inside of the parts 33a and 33b respectively. Alternatively, the annular element 31 can be machined from a solid bar, and hence the need for welding is avoided.

The operation of the safety system is now described. An expandable support system 1, provided with mounting locations 10 in the exterior section 15 of the internal strut element 3 is introduced to the location where support is required. The expandable support system 1 is introduced in the first, reduced, length state and is then expanded until the ends contact the structural elements 9 to be supported. The expandable support element 1 is thus transitioned to the second, increased, length state. As a result of the transition to the second, increased length state, at least two of the mounting locations 10 is exposed on the exterior of the internal strut element 3 and is no longer within the external strut element 5. In this state, the expandable support system 1 is providing the necessary support function, but there is a risk of uncontrolled transition towards the first, reduced, length state.

The second part of the safety system, the restraint 29, can now be introduced to provide the expandable support system 1 in a third, restrained, state. This is done by attaching lifting means to the lifting location 43 provided on the head block 39. The nut 51 and bolt 49 are removed from the projections 45a and 45b. The restraint 29 is lifted to an upright position, with the head block 39 at the top and base split 35 at the bottom.

Using optional handles 55, shown in Figure 5, it is possible for operators to open the two parts 33a and 33b so as to open the restraint 29 to an open state. This configuration is shown in Figure 4. In the open state, the restraint 29 is lifted above the expandable support system 1 and then lowered into position with both parts 33a and 33b engaging in exposed mounting locations 10.

In Figure 4 the illustration is in relation to the expandable support system 1 without load, but in use the end bearing plate 7 would bear directly or indirectly against the structural element 9 to be supported and the expandable support system would already be in the second, increased, length state.

Once the restraint 29 is positioned over the internal strut element 3, the restraint 29 is moved towards the external strut element 5, until the restraint 29 is positioned close to the first groove 13a and second groove 13b which are accessible on the exterior of the internal strut element 3; those grooves just exposed after the receiving end 57 of the external strut element S. The two parts 33a, 33b of the restraint 29 are then brought together. Referring to the configuration of the grooves 13a, 13b, the inclined guide surface 27 assists in positioning the projection elements 53a, 53b, inside the grooves 13, 13b, respectively, with the projection elements 53a, 53b resting in close proximity to the base 25 and abutting the abutment surface 21. The bolt 49 is then inserted and the nut 51 tightened to hold the two parts 33a, 33b of the restraint 29 together. The restraint 29 is now in a closed state.

This configuration also provides the expandable support element 1 in a third, restrained, state.

Figure 5 illustrates the closed state for the restraint 29 in relation to a further embodiment of the invention. In this closed state, with the restraint 29 positioned proximal to the receiving end 57 of the external strut elements, should there be a failure in the expandable support system 1, then the internal strut element 3 can only move back into the external strut element 5 to a very limited extent. The extent allowed is defined by the gap between the face of the receiving end 59 of the external strut element 5 and the back face of the restraint 29. Once the expandable support system 1 has moved by amount matching the gap then the abutment of the projection element 53a with its respective abutment surface 21 and projection element 53b with its abutment surface 21 restrain further movement. The very limited movement allowed by the safety system means that the expandable support system 1 will still remain in its suspended position within the excavation site and load holding capability is still provided to the structural elements 9, such as shoring. In this way the invention provides a full mechanical restraint against inadvertent movement of the expandable support system 1 away from the second, increased, length state towards the first, reduced, length state. Thus even should the hydraulics fail there is reassurance to the operator and protection for the operators due to this mechanical limit. Typically, a 20mm limit on contraction is provided.

Referring back to Figure 3b, within the restraint 29, the two projection parts 53a and 53b are offset, relative to their axial position along the long axis 11, within the restraint 29. This means that by rotating the restraint 29 through 1800 it is possible to achieve an alternative positioning of the restraint 29 on the exterior profile 17 of the internal strut element 3 and hence vary the gap between the restraint 29 and the receiving end face 59 of the external strut element 5. This allows closer positioning of the restraint 29 relative to the external strut element 5 and so minimises the contraction should a failure occur.

The clamshell arrangement offered by the restraint 29 represent a convenient mode for 10 introducing and then clamping the two parts of the second part of the safety system together and yet allows ready release of the two should that be necessary once removal of the expandable support system 1 is required at the end of its operation.

To construct the restraint, the two parts 33a, 33b are readily provided by cutting the necessary length of an existing tube and then slicing that into two halves. In the alternative, the annular element 31 is machined from a solid bar. The projection elements 53a, 53b, are easily provided within the parts 33a, 33b, by welding two hoops to the inside of the tube and then slicing those at the same time as the tube. A continuous run is provided by the projection elements 53a, 53b, around the entire circumference of the parts 33a, 33b.

As illustrated in reference to Figure 2a the abutment surface 21 in the groove 13 is always perpendicular to the load from the expandable support element 1 that acts through the internal strut element 3 to the abutment surface 21, then to the projection elements 53 and hence to the restraint 29 generally and then against the receiving end face 59 of external strut element 5. If necessary, the receiving end 57 can be provided with a receiving end face [not shown] in the form of an annular element mounted on the receiving end 57 and offering a larger diameter planar perpendicular face in abutment.

The safety system developed is an improvement over the prior ad, firstly, in offering a mechanical restraint to contraction of the expandable support system 1. Secondly, in offering such a system in a manner which takes the load from the support system evenly. This is in contrast for instance with the use of welding locations on the internal strut element and external strut element and providing spacing bars extending between the two. These bars are put under compression in the event of any failure and are thus themselves prone to deform and not offer the restraint required. Furthermore such systems are not reusable and need to be replaced each time due to being constructed by welding and cut off to remove.

The expandable support system 1 can be provided with a wide variety of internal strut element 3 and/or external strut element 5 configurations whilst using the principles of the present invention. Thus the expandable support system 1 can still be provided in a variety of lengths so as to give the necessary combinations of overall length and adjustment desired.

The system of the invention is also preferable to the prior art in avoiding any form of threaded system in the restraint. With a thread, if a reduction in expandable support system 1 length occurs, then the safety system is heavily loaded and a threaded system is then very hard to release whilst under load. The invention is preferable in this respect as it is only loaded when failure occurs rather than having to be screwed down and hence loaded at all times. The system of the invention also offers up to 20mm of adjustment with the restraint 29 in any one position, so as to allow normal fluctuation in the hydraulic system. If the safety system was screwed down, for instance, then any normal fluctuation would lead to heavy loading.

Figure 6 provides an illustration of the expandable support system 1 and safety system in use. The support system 1 is formed of an internal strut element 3 slidably received within an external strut element 5. The internal strut element 3 carries an end bearing plate 7. A 30 similar end plate 7 is provided at the other end on the external strut element 5. The first part of the safety system is provided by the internal strut element 3 having a series of mounting locations 10. These are not provided by a helical groove, but rather a series of annular grooves provided perpendicular to the long axis of the expandable support system 1. The second part of the safety system for the expandable support system 1 is provided by the restraint 29 which surrounds the expandable support system 1 and engages with two of the annular grooves on the internal strut element 3. The restraint 29 limits retraction of the internal strut element 3 into the external strut element 5 when the restrain 29 abuts the end of the external strut element 5.

Claims

CLAIMS1. A safety system, the safety system comprising: a restraint; and a strut element; wherein the restraint comprises: a body, the body including a first part and a second part, both the first part and the second part having an outer surface and an inner surface, the first part and the second part defining at least a part of the perimeter around a space, the first part having an end and the second part having an end; a plurality of projection elements; wherein at least one projection element is provided on the inner surface of the first part and at least one projection element is provided on the inner surface of the second part; wherein the restraint has an open state and a closed state, the open state providing a gap between the end of the first part and the end of the second part, the closed state providing a reduced gap between end of the first part and the end of the second part; and wherein the strut element comprises: an external surface, the external surface having an exterior section, the exterior section being provided with one or more mounting locations for a restraint.
2. A restraint, preferably for a safety system according to claim 1, the restraint comprising: a body, the body including a first part and a second part, both the first part and the second part having an outer surface and an inner surface, the first part and the second part defining at least a part of the perimeter around a space, the first part having an end and the second part having an end; a plurality of projection elements; wherein at least one projection element is provided on the inner surface of the first part and at least one projection element is provided on the inner surface of the second part; wherein the restraint has an open state and a closed state, the open state providing a gap between the end of the first part and the end of the second part, the closed state providing a reduced gap between end of the first part and the end of the second part.
3. The safety system of claim 1 or claim 2 and/or restraint of claim 2, wherein the body comprises a mounting element and the mounting element provides a pivotal mounting for the first part and/or the second part.
4. The safety system of any of claims 1 to 3 and/or restraint of claim 2 or claim 3, wherein the first part is provided with part of a releasable fastener assembly and the second part is provided with a further part of the releasable fastener assembly.
5. The safety system of any of claims 1 to 4 and/or restraint of any of claims 2 to 4, wherein a top split between the first part and the second part is provided proximal a mounting element and a bottom split between the first part and the second part is provided proximal the releasable fastener assembly. 6. 7. 8.
The safety system of any of claims 1 to 5 and/or restraint of any of claims 2 to 5, wherein the inner surface of the first part and/or second part are provided with two or more projection elements.
The safety system of claim 6 and/or restraint of claim 6, wherein the two or more projection elements are spaced from one another along the longitudinal axis of the restraint.
The safety system of any of claims 6 or 7 and/or restraint of any of claims 6 or 7, wherein the projection elements on the first part extend over 70% of the length of the inner surface of the first part and/or the projection elements on the second part extend over 70% of the length of the inner surface of the second part.
9. The safety system of any of claims 6 to 8 and/or restraint of any of claims 6 to 8, wherein a projection element on a first part in combination with a projection element on a second part forms an annular projection.
10. The safety system of any of claims 6 to 9 and/or restraint of any of claims 6 to 9, wherein the spacing of the projection elements along the axis is greater than 2cm and less than 12 cm between the start of one projection element and the start of the next projection element.
11. The safety system of any of claims 6 to 10 and/or restraint of any of claims 6 to 10, wherein one or more or all of the projection elements have a height, extending into the space, greater than 0.5cm relative to the inner surface of the part and/or one or more or all of the projection elements have a width of greater than 5cm.
12. The safety system of any of claims 1 to 11 and/or restraint of any of claims 2 to 11, wherein the open state for the restraint provides a minimum gap between the end of the first part and the end of the second part of greater than 30cm.
13. A strut element, preferably for a safety system according to any of claims 1 to 12 and/or restraint of any of claims 2 to 12, wherein the strut element comprises an external surface, the external surface having an exterior section, the exterior section being provided with one or more mounting locations for a restraint.
14. The safety system of any of claims 1 to 13 and/or strut element of claim 13, wherein the strut element is an internal strut element and the internal strut element is received within an external strut element or wherein the strut element is an external strut element and the external strut element receives an internal strut element.
15. The safety system of any of claims 1 to 14 and/or strut element of claim 13 or claim 14, wherein a plurality of mounting locations are provided and/or a plurality of mounting locations are provided spaced along the longitudinal axis of the strut element.
16. The safety system of any of claims 1 to 15 and/or strut element of any of claims 13 to 15, wherein at least 5 mounting locations are provided at different extents along the longitudinal axis.
17. The safety system of any of claims 1 to 16 and/or strut element of any of claims 13 to 16, wherein one or more of the mounting locations are provided within an exterior section of the strut element and the exterior section is proximal to another strut element, in use, but not covered by that another strut element in use.
18. The safety system of any of claims 1 to 17 and/or strut element of any of claims 13 to 17, wherein one or more or all of the mounting locations are recesses in the exterior section of the strut element.
19. The safety system of claim 18 and/or strut element of claim 18, wherein the mounting location is all recessed within the external profile of the strut element, with no part of the mounting location extending beyond the external profile of the strut element, the external profile of the strut element being the external profile which is received within another strut element.
20. The safety system of any of claims 1 to 19 and/or strut element of any of claims 13 to 19, wherein one or more of the mounting locations extend around the full periphery of the strut element, for instance as continuous channel or groove.
21. The safety system of any of claims 1 to 20 and/or strut element of any of claims 13 to 20, wherein a mounting location is formed of a single continuous groove --3 1 -extending around the full periphery of the strut element and/or each of the mounting locations is a separate groove spaced along the strut element.
22. An expandable support system, the expandable support system comprising: a first strut element; and a second strut element; wherein a part of one of the strut elements is slideably received within the other of the strut elements, the expandable support system having a first reduced length state and a second increased length state; wherein at least one of the strut elements comprises an external surface, the external surface having an exterior section, the exterior section being provided with one or more mounting locations for a restraint, for instance according to any of claims 2 to 12.
23. A method of providing a safety system on an expandable support system, the method including: providing a restraint adjacent the expandable support system; lifting the restraint onto the expandable support system; and then placing the restraint in a closed state around a strut element of the expandable support system to form the safety system, preferably wherein the restrain is provided according to any of claims 2 to 12.
24. A method of supporting a location, the method comprising: introducing an expandable support system into a location; providing the expandable support system in a supporting state in the location; then providing a safety system on an expandable support system, by: providing a restraint adjacent the expandable support system; lifting the restraint onto the expandable support system; and then placing the restraint in a closed state around a strut element of the expandable support system to form the safety system, preferably wherein the restrain is provided according to any of claims 210 12 and/or the safety system is provided according to any of claims 1 to 21.