GB2466768A

GB2466768A - A clamp having a pivotal hook and locking element

Info

Publication number: GB2466768A
Application number: GB0823580A
Authority: GB
Inventors: Mark Taylor
Original assignee: SGB Services Ltd
Current assignee: SGB Services Ltd
Priority date: 2008-12-30
Filing date: 2008-12-30
Publication date: 2010-07-07
Anticipated expiration: 2028-12-30
Also published as: GB2466768B; GB0823580D0

Abstract

A clamp for securing to a scaffolding element, the clamp comprising an upper hook 3; a lower hook 7, pivotable between an open position, in which a scaffolding element may be inserted between the upper and lower hooks, and a closed position, in which the upper and lower hooks together clamp around a scaffolding element 2; and a locking element 11 movable between: a first position, in which the lower jaw 7 is held in the open position; and a second position, in which the lower jaw is held in the closed position. The locking element may be a stepped wedge which is slid into position. With sufficient shock during placement of the upper jaw 3 on a scaffolding element 2 the wedge may become dislodged and allow the lower hook 7 to pivot into the closed position due to gravity; the wedge then falls into a lower position securing the clamp in the closed position. The locking element 11 may have protruding fingers 15 which automatically move the lower hook to the open position as the wedge is moved from held closed position to the held open position. The clamp may be used for securing an advance guard rail to an upper level from the level below.

Description

Title: A Clamp

Description of Invention

THE PRESENT INVENTION relates to a clamp for securing to a scaffolding element. An advance guard rail including a clamp is also disclosed.

When building a construction having a central core and floors formed by poured concrete, the structure commonly has no external wall and thus the floors are open to the elements. It is only the façade that is added to the building later in the construction process which encloses the perimeter of the building. Workers working at height erecting scaffolding are at particular risk.

Provisions must be made to ensure that suitable guards or rails are put in place to prevent workers from falling off the side of a newly constructed floor.

It is known to provide temporary guard rails around the perimeter of the floors on which staff are working. These are either temporarily clamped to the floor or are removably attached to anchor points embedded in the side of the floor.

As more floors are formed, more guard rails need to be put in place to provide safety to the workers, at least until a more permanent rail is secured in place.

The Work at Height Regulations 2005 (a statutory instrument of the British Parliament and administered by the British Health & Safety Executive) require stringent safety procedures to be in place. With the above described guard rail system, it will necessarily be the case that a worker needs to be on the unprotected floor in order to fit the guard rail. Naturally, before the guard rail has been fitted, there are no other safety provisions for that worker.

There is a requirement, therefore, for a system which affords greater safety to construction workers.

Accordingly, the present invention provides a clamp and a method according to the claims.

Embodiments of the present invention will now be described, by way of example only, with reference to the following figures, in which: FIGURE 1 shows a clamp embodying the present invention, in an open position; FIGURE 2 shows the clamp of Figure 1 in a closed position, secured to a scaffolding element; FIGURE 3 shows a locking element embodying the present invention; FIGURE 4 shows an advance guard rail system embodying the present invention; and FIGURE 5 shows the installation of an advance guard rail; Figures 1 and 2 show a clamp 1 embodying the present invention. The clamp 1 is suitable for securing to a scaffolding element 2.

The clamp 1 comprises an upper hook 3. The upper hook 3 comprises two hook members 4 and a back plate 5.

The clamp 1 further comprises a lower hook 7, comprising two hook members 8 and a bridging element 9. The upper hook 3 and lower hook 7 are connected to one another and pivot about an axis 10.

The clamp 1 further comprises a locking element 11. The locking element 11 comprises a first portion 12 and a second portion 13, with a step 16 therebetween. The locking element 11 further comprises a handle portion 14.

Two detents 15 are provided at a lower end of the locking element 11.

Preferably, the detents 1 5 extend beyond the width of the first portion 1 2 of the locking element 11.

The locking element 11 is retained against the back plate 5 of the upper hook 3, and translates with respect thereto. In the embodiment shown, a pin 6 of the upper plate 3 rides in a slot 17 provided on the locking element 11.

In the configuration shown in figure 1, the clamp 1 is in an open position. It will be seen that the upper 3 and lower 7 hooks are arranged such that they may receive a scaffolding element 2 therebetween. It will further be noted, with 1 5 reference to figure 1, that the lower hook 7 is positively held in the open position by the locking element 11. Specifically, it will be noted that the step 16 between the first 12 and second 13 portions of the locking element 11 engages against a top surface of the bridging element 9 of the lower hook 7.

The step 16 is at an acute downward angle to the vertical plane in which the locking element 11 translates (i.e. it is not at a right angle). As a result, the weight of the locking element 11 ensures that the step 16 thereof engages against the top portion of the bridging element 9, to positively hold the lower hook in the open position. As a result, in the configuration of the clamp 1 shown in figure 1, the combination of the weight of the locking element 11 and the angled step 16 causes the lower hook to be urged about the pivot 10 in an anti-clockwise direction keeping it open. In another embodiment, the surface of the step 1 6 may be at a right angle to the plane in which the locking element 11 translates.

Figure 2 shows the clamp 1 in a closed position, secured to a scaffolding element 2. It will be seen in figure 2 that both hook members 4 of the upper hook 3 and hook members 8 of the lower hook 7 are clamped around a scaffolding element 2, thereby securing the clamp 1 to the scaffolding element 2. Further, it will be noted that as a result of the lower hook 7 rotating about the pivot 10 in a clockwise direction, the distance between the back plate 5 of the upper hook 3 and bridging element 9 of the lower hook 7 has increased beyond that in figure 1. As a result, the locking element 11 has fallen under gravity and translated along the vertical axis (guided by the pin 6 and slot 17, as described above). As shown in figure 2, the top portion of the bridging element 9 is no longer in engagement with the step 1 6 of the locking element 11. Instead, the locking element 11 has translated to a point where the inside surface of the bridging element 9 is in engagement with a second portion 13 of the locking element 11. As will be seen in figure 2, the rear surface of the bridging element 9 is substantially parallel to the surface of the second portion 1 3 of the locking element 11. The second portion 1 3 of the locking element 11 has a wedged profile.

In one embodiment, as the locking element 11 moves in a downward direction, the momentum of the locking element 11 causes the locking element 11 to at least partially wedge between the back plate 5 of the upper hook 3 and bridging element 9 of the lower hook 7. In this configuration, it will be noted that the locking element 11 positively holds the lower hook 7 in a closed position. A wedging force can further be applied by hitting the handle portion 14 of the locking element 11 with a hammer or another means of imparting a force. If a force is applied to the handle 14, it will be appreciated that the wedged profile of the second portion 1 3 of the locking element 11 engages against the bridging element 9 of the lower hook 7 and causes the lower hook 7 to rotate about the pivot 10 in a clockwise direction, thereby imparting an even greater clamping force around the scaffolding element 2.

To move the lower hook 7 from a closed position to an open position, the locking element 11 must be moved in a vertically upwards direction. The locking element 11 may be moved by hand by engaging a user's fingers with the underside of the handle 14. If the locking element 11 is firmly wedged between the back plate 5 of the upper hook 3 and bridging element 9 of the lower hook 7, a force may be imparted on the underside of the handle 14. The movement of the locking element 11 in a vertically upwards direction allows the lower hook 7 to rotate about the pivot in an anti-clockwise direction to the configuration shown in figure 1, allowing the clamp 1 to be removed from the scaffolding element 2.

As will be seen from the figures, the lower end of the locking element 11 comprises two detents 1 5. When the locking element 11 is raised vertically, the detents 15 engage against the underside of a bridging element of the lower hook 7 to cause the lower hook 7 to rotate about the pivot 10 in an anti-clockwise direction.

As the locking element 11 is raised to its top extreme, the lower hook 7 is caused to rotate in an anti-clockwise direction to the extent that the top edge of the bridging element 9 engages beneath the step 16 of the locking element 11.

The clamp 1 has thus returned to the configuration shown in figure 1, where the lower hook 7 is positively held in an open position.

Preferably, the distance between the step 16 and detents 15 is substantially equal to the height of the bridging member 9 of the lower hook 7.

The clamp 1 may be fixed to a further scaffolding element, such as a rail 17.

As shown in the figures, the back plate 5 of the upper hook 3 is secured to the rail 17 by a through-bolt. A through-bolt may also provide the pin 6 along which the slot 50 of the locking element 11 translates. The pivot 10 may also be provided by a through-bolt passing through the rail 17. Accordingly, both the upper 3 and lower 7 hooks may be secured to the rail 17, and pivot with respect to one another, by the provision of a single through-bolt along the axis 10.

In another embodiment, the clamp 1 may be secured to the rail 17 at other points to those shown. The pivot point 10 may comprise an upstanding peg welded to or formed integrally with the side of each hook member 4 of the upper hook 3. Each peg may be received through an aperture in the hook member 8 of the lower hook 7. The pegs would not, therefore, pass all the way through the rail 17. A similar arrangement could be provided with the pin 6 of the upper hook 3. Specifically, the pin 6 could be a peg formed integrally with or welded to the back plate 5 of the upper hook 3. The end of the peg could be threaded, to which a respective nut is attached, thereby retaining the locking element 11 in sliding engagement with the back plate 5 of theupperhook3.

By providing two hook members 4, 8 on each of the upper 3 and lower 7 hooks, the clamp 1 is secured to the scaffolding element 2 in such a way that it may only rotate about the longitudinal axis of the scaffolding element 2.

Rotation of the clamp 1 around the longitudinal axis of the scaffolding element 2 may be prevented by wedging the locking element 11 between the back plate 5 of the upper hook 3 and bridging element 9 of the lower hook 7.

The clamp 1 may thus be secured to a scaffolding element 2 in all degrees of freedom. Although both the upper 3 and lower 7 hooks are shown provided with two hook members 4, 8 each, another embodiment provides an upper hook 3 and lower hook 7 each having only a single hook member 4, 8.

It will be appreciated that the locking element 11 may be configured such that the clamp 1 is operable to secure to a scaffolding element of varying profiles and diameters. For example, the second portion 13 of the locking element 11 may be configured such that it provides a wedging force between the back plate 5 and bridging element 9 across a range of varying distances between the upper hook 3 and lower hook 7. The hook elements 4, 8 of the upper 3 and lower 7 hooks may be configured so that they substantially extend around the whole circumference of the scaffolding element 2 when in the closed position. When in the open position, the distance between the tips of the hook elements 4, 8 is preferably greater than the diameter of the scaffolding element 2 to which the clamp 1 is to be secured.

Preferably, the rail 17 forms part of an advance guard rail 18, shown in figure 4. The advance guard rail 18 comprises two vertical rails 17 (as shown in figures 1 and 2), joined by horizontal cross members 19. The lower end of each vertical rail 17 is provided with a hooked portion 20. Preferably, the hook portion 20 comprises a downward facing hook. Above each hooked portion 20 is provided a clamp 1 embodying the present invention. In another embodiment, the hook portions 20 could comprise the clamps 1 embodying the present invention.

The advance guard rail 18 embodying the present invention is operable to engage with and secure to a construction comprising two horizontal, vertically spaced, scaffolding elements 2. As will be appreciated from figure 4, the advance guard rail 18 is installed by engaging the respective scaffolding element 2 with the hooked portion 20 and the upper hook 3 of each clamp 1.

Each clamp 1 of the advance guard rail 18 is secured to the scaffolding element 2 as described above. Specifically, the locking element 11 is moved in a downward vertical direction, so as to cause the lower hook 7 to pivot from an open position to a closed position. The locking element 11 may further be hammered into place to wedge the locking element 11 between the back plate 5 of the upper hook 3 and the bridging element 9 of the lower hook 7.

As will be appreciated from figure 4, the vertical rails 17 extend a distance below the horizontal members 19. Preferably, the distance is such that the advance guard rail 18 can be attached to scaffolding elements 2 from a floor below that for which the advance guard rail 18 is being installed. Accordingly, there is no need for a worker to access the as-yet-unguarded floor to install the advance guard rail 18. The advance guard rail 18 can at least partially be secured to the scaffolding element 2 from the current floor. Then, having at least partially installed the advance guard rail 18 in place, the worker can safely climb to the next floor, and more rigidly attach the advance guard rail 1 8 in place (i.e. by firmly wedging the locking element 11 into place). Alternatively, a worker may rigidly attach the advance guard rail in place from the existing floor. It is to be appreciated that the provision of an advance guard rail 18 embodying the present invention means that a worker may never need to access a floor which is completely unguarded around its perimeter.

A particular advantage of a clamp 1 embodying the present invention is that the mere impact of the hook members 4 of the upper hook 3 against a scaffolding element 2 may cause a shock to travel through the clamp 1, with the effect that the upper portion of the bridging element 9 of the lower hook 7 will move out of engagement with the step 16. In one embodiment, the lower hook 7 is configured such that its centre of gravity does not lie on the axis of rotation 1 0. Preferably, the lower hook 7 is pivoted such that it naturally tends to rotate in a clockwise direction about the axis 10, such that it is urged, by gravity, into a closed configuration. Accordingly, engaging the upper hook 3 against a scaffolding element 2 may cause a sufficient shock to travel through the clamp 1, which causes the lower hook 7 to move from an open to a closed configuration, without needing any manual intervention with the clamp 1. The clamp 1 therefore self-closes, at least to some extent, around the scaffolding element 2. The clamp 1 can further be rigidly secured to the scaffolding element by applying a force to the handle 14 of the locking element 11 to wedge the locking element 11 into place. However, as explained above, as the locking element 11 falls from its top to its lower position, the momentum of the locking element 11 may cause a sufficient wedging force to be supplied between the back plate 5 of the upper hook 3 and the bridging element 9 of the lower hook 7.

A method of installation of an advance guard rail embodying the present invention will now be described, with reference to figure 5. Figure 5 (A) shows two adjacent floors 21, 22 of a construction. The edge of lower floor 21 is guarded by an advance guard rail embodying the present invention, which is secured to scaffolding elements 2A, 2B. Accordingly, a worker 23 (not shown in figure 5 (a)) standing on the lower floor 21 may safely work on lower floor 1 0 21, without risk of falling off the side of the construction, owing to the presence of the horizontal cross members 1 9 of an advance guard rail system 1 8. Other scaffolding elements 2c-2f may enclose the floor, to which a more permanent safety guard may be attached. Alternatively or additionally, a worker may install an outer wall or façade, such that the guard rail 1 8 is no longer required.

As shown in figure 5 (B), when a worker 23 wishes to commence work on the upper floor 22 above the current floor 21, the worker 23 needs to ensure that adequate safety provisions are in place before accessing the upper floor 22.

Accordingly, an advance guard rail embodying the present invention allows the worker 23 to at least partially install the advance guard rail from the lower floor 21, to provide safety for a worker accessing the upper floor 22. As shown in figure SB, a worker 23 picks up and extends an advance guard rail 18 to a point vertically above his current position on the lower floor 21. The worker 23 engages the upper hook 3 and hook portion 20 with respective scaffolding elements 2E, 2F (which are above the scaffolding elements 2A, 2B). In so doing, as described above, the mere impact of the hooks 4 of the upper hook 3 against a scaffolding element (in this case, scaffolding element 2F) may cause a shock to travel through the clamp 1, with the effect that the lower hook 7 moves to the closed position. There may be no need for any manual intervention by the worker 23 with the hook 1 to move it from the open to closed position.

After the worker 23 has installed the advance guard rail 18 on the upper floor 22, the worker can then safely access the upper floor 22, with at least a reduced risk of falling off the upper floor 22. He can complete the installation and carry out any adjustments to the clamp 1 from the upper floor 22.

Preferably, the advance guard rail 18 is configured such that when in place, a worker can access the clamp 1 from either the newly guarded floor (as shown in figure 5(c)), or from the floor below. This is beneficial since it would be more difficult for the worker 23 to apply a hammer force to the locking element from the floor 21 below. Providing the advance guard rail 18 embodying the present invention allows a worker to apply a hammer force from above (from upper floor 22) to the locking element 11.

Conveniently, a clamp 1 embodying the present invention allows for substantially one-handed operation. Accordingly, an advance guard rail system 18 embodying the present invention may be installed by one worker only. As shown in figure 5, a worker may hold each vertical rail 17 with one hand only. As each clamp 1 engages with a scaffolding element 2, each of the clamps 1 "self-close" about the scaffolding element 2.

When used in this specification and claims, the terms "comprises" and "comprising and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

CLAIMS1. A clamp for securing to a scaffolding element, comprising: an upper hook; a lower hook, pivotable between an open position, in which a scaffolding element may be inserted between the upper and lower hooks, and a closed position, in which the upper and lower hooks together clamp around a scaffolding element; and a locking element movable between: a first position, in which the lower hook is held in the open position; and a second position, in which the lower hook is held in the closed position.
2. A clamp according to claim 1, wherein at least a portion of the locking element is wedged.
3. A clamp according to any preceding claim, wherein a lower end of the locking element comprises at least one tang to engage with the lower hook to move the lower hook from a closed position to an open position.
4. A clamp according to any preceding claim, wherein the lower hook is pivotably attached to the upper hook.
5. A clamp according to any preceding claim, configured such that when the upper hook is brought into engagement with a scaffolding element, the locking element is caused to move from the first position to the second position, to allow the lower hook to pivot into the closed position.
6. A clamp according to any preceding claim, wherein the lower hook includes a protrusion, configured to engage with the scaffolding element when the lower hook is in the open position, to cause the lower hook to pivot into the closed position.
7. A clamp according to any preceding claim, wherein the upper hook comprises a back plate, to attach the clamp to a construction.
8. A clamp according to claim 7, wherein the lower hook comprises two hook members connected by a bridging element and the locking element is retained between the bridging element and the back plate of the upper hook.

1 0
9. A clamp according to any of claims 7 and 8, wherein the locking element is slideable with respect to the back plate of the upper hook.
1 0. A clamp according to any preceding claim, wherein the locking element has a non uniform profile.
11. A clamp according to any preceding claim, wherein the locking element is stepped, a first portion to hold the lower hook in the open position and a second portion to hold the lower hook in the closed position.
1 2. A clamp according to claim 11, wherein the bridging element of the lower hook, in the open position, bears against the step between the first and second portions of the locking element.
13. A clamp according to any preceding claim, wherein the lower hook is urged into the closed position by gravity.
14. An advance guard rail comprising at least one clamp according to any preceding claim.
15. A method of a securing a clamp to a scaffolding element, the clamp comprising an upper hook; a lower hook, pivotable between an open position and a closed position; and a locking element movable between: a first position and a second position, the method comprising: providing the clamp with the locking element in a first position, thereby holding the lower hook in an open position, engaging the clamp with a scaffolding element; and moving the locking element to a second position, thereby holding the lower hook in a closed position.
1 6. A method according to claim 1 5, wherein engaging the clamp with a 1 0 scaffolding element causes the locking element to move to the second position.
1 7. A method according to any of claims 1 5 and 1 6, further comprising applying a force to the locking element when in the second position.
18. A method of securing an advance guard rail, according to claim 14, to a scaffolding member at an elevated height, the method comprising: lifting the advance guard rail to the elevated height; and performing the method according to any one of claims 15 to 17.
19. A clamp, advance guard rail or method substantially as described herein.
20. Any novel matter or combination thereof.Amendments to the claims have been filed as followsCLAIMS1. A clamp for securing to a scaffolding element, comprising: a stationary upper hook; a lower hook, pivotable with respect to the upper hook between an open position, in which a scaffolding element may be inserted between the upper and lower hooks, and a closed position, in which the upper and lower hooks together clamp around a scaffolding element; and a locking element slidably retained against the upper hook and linearly translatable between: a first position, in which the lower hook is held in the open position; and a second position, in which the lower hook is held in the closed position.2. A clamp according to claim 1, wherein at least a portion of the locking (Y) 15 element is wedged.3. A clamp according to any preceding claim, wherein a lower end of the locking element comprises at least one tang to engage with the lower hook to move the lower hook from a closed position to an open position.4. A clamp according to any preceding claim, wherein the lower hook is pivotably attached to the upper hook.5. A clamp according to any preceding claim, configured such that when the upper hook is brought into engagement with a scaffolding element, the locking element is caused to move from the first position to the second position, to allow the lower hook to pivot into the closed position.6. A clamp according to any preceding claim, wherein the lower hook includes a protrusion, configured to engage with the scaffolding element when the lower hook is in the open position, to cause the lower hook to pivot into the closed position.7. A clamp according to any preceding claim, wherein the upper hook comprises a back plate, to attach the clamp to a construction.8. A clamp according to claim 7, wherein the lower hook comprises two hook members connected by a bridging element and the locking element is retained between the bridging element and the back plate of the upper hook.9. A clamp according to any of claims 7 and 8, wherein the locking element is slideable with respect to the back plate of the upper hook.10. A clamp according to any preceding claim, wherein the locking element CY) 15 has a non uniform profile.11. A clamp according to any preceding claim, wherein the locking element is stepped, a first portion to hold the lower hook in the open position and a second portion to hold the lower hook in the closed position.12. A clamp according to claim 11, wherein the bridging element of the lower hook, in the open position, bears against the step between the first and second portions of the locking element.13. A clamp according to any preceding claim, wherein the lower hook is urged into the closed position by gravity.14. An advance guard rail comprising at least one clamp according to any preceding claim.15. A method of a securing a clamp to a scaffolding element, the clamp comprising a stationary upper hook; a lower hook, pivotable with respect to the upper hook between an open position and a closed position; and a locking element slidably retained against the upper hook and linearly translatable between: a first position and a second position, the method comprising: providing the clamp with the locking element in a first position, thereby holding the lower hook in an open position, engaging the clamp with a scaffolding element; and linearly translating the locking element to a second position, thereby holding the lower hook in a closed position.16. A method according to claim 15, wherein engaging the clamp with a scaffolding element causes the locking element to move to the second position.C') 15 Q 17. A method according to any of claims 15 and 16, further comprising applying a force to the locking element when in the second position.18. A method of securing an advance guard rail, according to claim 14, to a scaffolding member at an elevated height, the method comprising: lifting the advance guard rail to the elevated height; and performing the method according to any one of claims 15 to 17.19. A clamp; an advance guard rail comprising the clamp; or method substantially as described herein.