GB2426278A

GB2426278A - A climbing formwork system

Info

Publication number: GB2426278A
Application number: GB0510254A
Authority: GB
Inventors: Sgb Services Limited; Duncan Hyde
Original assignee: SGB Services Ltd
Priority date: 2005-05-19
Filing date: 2005-05-19
Publication date: 2006-11-22
Anticipated expiration: 2025-05-19
Also published as: GB2426278A8; GB0510254D0; GB2426278B

Abstract

A climbing formwork system comprises an elongate track 1 and a moveable formwork support assembly 3. The track is securable to a building structure 2 so as to lie substantially vertically up the building and has a plurality of support formations (33, Figure 10) at spaced apart positions along its length. The support assembly is selectively moveable up the building structure along the track, and to facilitate this the support assembly carries at least one latch 23 which is pivotally mounted about a respective substantially horizontal axis and is biased towards a locking position in which it engages a support formation on the track such that said support assembly can hang from the support formation as shown in Figure 15. The or each latch has a cam surface (37, Figure 10) configured to bear against the or each successive support formation so that the latch rotates out of its locking position in order to allow passage of the last latch past each successive support formation as the support assembly is moved up the track.

Description

A CLIMBING FORMWORK SYSTEM

THE PRESENT INVENTION relates to a climbing formwork system.

Concrete is very widely used in the construction industry and has been found to be particularly suitable for use as a structural material in the construction of high rise buildings or other similar structures which stand a considerable distance above ground level.

High rise buildings are often built around one or more central cores which run substantially the entire height of the building and which are fabricated from concrete, Of course, it is very often impractical or even impossible to pour sufficient concrete in a single step in order to fabricate a central core of this nature in one "pour". It is therefore common practice to build up a central core in a number of steps, with each step corresponding to one or more storeys of the building. In an example where the core of a high rise building is fabricated using a separate pour for each storey, then each successive pour can only take place after the concrete used to form the storey below has properly set.

Of course, all concrete pours need to be contained, in order to hold the concrete in place until it hardens sufficiently to hold its own shape. It is common practice to use some sort of temporary shuttering, also known as formwork, which must be sufficiently sturdy in order to bear the considerable forces created by the volume of wet concrete involved in the fabrication of a high rise building core, plus the weight and force of any vibration equipment.

It should be appreciated that as the height of the building core increases with successive pours, the height at which the formwork needs to be provided above ground level increases. It has therefore been proposed previously to provide systems of "climbing formwork" which provide movable formwork which can "climb" up the structure of the building core as the core increases in height. Some such systems use a series of tracks, wherein lengths of track are secured, in a vertical orientation, to the sides of the building core, once the concrete has set, and allow a formwork support assembly to move along the tracks, for example when lifted by a crane or pushed from below by some hydraulic assembly, so that the formwork support assembly can advance up the building structure as the build progresses. Of course, it is necessary to provide a mechanism whereby the formwork support assembly can be locked at desired positions along the tracks for each successive pour of concrete.

There have been various previous proposals for such locking mechanisms, but it has been found that some are unduly complicated or labourintensive to use which can slow the progress of a build.

It is therefore an object of the present invention to provide an improved climbing formwork system.

According to the present invention there is provided a climbing formwork system comprising: a substantially elongate track and a moveable formwork support assembly; the track being releasably securable to a building structure such that the longitudinal axis of the track lies substantially vertically, and having a plurality of support formations at spaced-apart positions along its length; said support assembly being selectively moveable up the building structure along the track; wherein said support assembly carries at least one latch, the or each latch being pivotally mounted about a respective substantially horizontal axis and biased towards a locking position in which it engages a said support formation such that said support assembly can hang from the support formation, the or each latch having a cam surface configured to bear against the or each successive support formation so that the latch rotates out of said locking position thereby allowing passage of the latch past each successive support formation as the support assembly is moved up the track.

Preferably, said support assembly is provided with a guide, the guide being configured to guide at least part of the track therethrough and retain the support assembly captive with respect to the track as the support assembly is moved up the track.

Advantageously, said latch is configured so as to be biased towards said locking position under the force of gravity.

Conveniently, said support assembly is provided with a stop against which part of said latch bears under gravity to define said locking position.

Preferably, said latch has a notch to engage said support formations.

Advantageously, said track has at least one flange spaced from said building structure when the track is secured to the building structure.

Conveniently, said track comprises a pair of spaced apart elongate rails, each said rail defining a respective said flange.

Preferably, said guide has a part which is located between said building structure and the or each said flange as the support structure moves along the track.

Advantageously, said guide comprises a guide shoe located between the building structure and the or each said flange.

Conveniently, each said support formation takes the form of a pin extending between said spaced apart rails.

Preferably, each rail is provided with a plurality of holes along its length, the holes of one rail being aligned with those of the other rail, and wherein said pins extend from respective holes in one of the rails to the aligned holes of the other rail.

Advantageously, said pins are selectively positionable between said rails.

Conveniently, said track is provided as a number of discreet lengths, each length of track being separately securable to the building structure and having at least one support formation.

Preferably, each said length of track is provided with two support formations.

Advantageously, said support assembly comprises a pair of spaced-apart elongate rails, the or each said latch being pivotally mounted about a respective pivot extending between said rails.

Conveniently, said stop extends between the two rails of the support assembly.

Preferably, the rails of the support assembly are substantially identical in cross-section to the rails of the track.

Advantageously, the support formations of the track are equi-spaced by a distance d, and wherein said support assembly carries two latches arranged one above the other, the axes about which the latches pivot being spacedapart by a x d, where a is an integer greater than zero.

So that the invention may be more readily understood, and so that further features thereof may be appreciated, an embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which:- FIGURE 1 is a perspective view of part of a climbing formwork system of the present invention, illustrated at ground level; FIGURE 2 is a side elevational view illustrating the climbing formwork system of the present invention, with moving formwork supported by a formwork support assembly; FIGURE 3 is a view corresponding generally to that of Figure 2, illustrating the moving formwork in a position ready for concrete to be poured; FIGURE 4 is an enlarged perspective view from one side and below of a locking mechanism of the present invention; FIGURE 5 is a perspective view from the side and above of the locking mechanism illustrated in Figure 4; FIGURE 6 is a view corresponding generally to that of Figure 3, illustrating the moving formwork in a position which it adopts after the concrete has been poured, and showing a length of track secured to the concrete just poured; FIGURE 7 is a view corresponding generally to that of Figure 6, illustrating the climbing formwork system of the present invention just prior to it being lifted; FIGURE 8 is a view corresponding generally to that of Figure 7, showing the formwork being lifted; FIGURE 9 is a view corresponding generally to that of Figure 8, illustrating the formwork located at a successive position up the building structure; FIGURE 10 is a perspective view of the locking mechanism of the present invention, with some parts removed for clarity; FIGURE 11 is a view corresponding generally to that of Figure 10, illustrating the mechanism in a position during lifting of the formwork support assembly; FIGURE 12 is a view corresponding generally to that of Figure 11, showing a subsequent position of the locking mechanism during the lift; FIGURE 13 is a view corresponding generally to that of Figure 12, illustrating the position of the locking mechanism at a still further instance during the lift; FIGURE 14 is a view corresponding generally to that of Figure 13, showing the locking mechanism as the movable formwork support assembly is subsequently lowered; and FIGURE 15 illustrates the locking mechanism in a position in which the formwork support assembly is locked along the track.

Referring initially to Figure 1, there is illustrated part of a climbing formwork system, shown against the lower part of a building structure 2 such as, for example, the ground-floor level of a partially-completed high rise building core.

The formwork system comprises a pair of vertically-oriented and spacedapart tracks 1, each of which are releasably secured to the building structure 2 in a manner which will be described in more detail hereinafter. Positioned against the two tracks I is a movable formwork support assembly, indicated generally at 3, which comprises a pair of spaced-apart and vertically oriented primary support members 4, each of which is arranged immediately adjacent a respective track 1. As will be described in more detail, the two primary support members 4 are configured to move vertically upwards along the respective tracks I as the movable formwork support assembly 3 is lifted away from the ground level position illustrated in Figure 1.

The movable formwork support assembly also comprises a pair of secondary support members 5, each of which is of substantially identical form to the primary support members 4. At their lower ends, the secondary support members 5 are spaced apart from respective primary support members 4 by a lower beam 6. The upper ends of the primary support members 4 and the secondary support members 5 are interconnected by a pair of substantially horizontal upper beams 7, each of which extends from the upper end of the respective primary support members 4 and passes the secondary support members 5 so as to terminate at a position spaced significantly from the building structure 2.

The terminal ends 8 of the upper beams 7 are each supported by a respective diagonal brace 9 which extends from the terminal end 8 of the upper beam 7 to the lower region of the respective secondary support member 5. Other braces can be provided on the structure as indicated in Figure 1.

Turning now to consider Figure 2, the components of the climbing formwork system illustrated in Figure 1 are shown from the side, positioned against a building structure 2 at ground level. The building structure 2 is approximately one storey high and is formed of concrete which has already been poured and which has been allowed to set. Figure 2 illustrates a formwork arrangement, indicated generally at 10, which is mounted on top of, and supported by, the movable formwork support assembly 3. The formwork arrangement comprises a carriage 11 which is supported for sliding movement along an elongate slide-bar 12 which is spaced slightly above the upper beams 7 of the support assembly 3. The carriage 11 is mounted for fore and aft movement, as indicated by arrow 13, along the slide-bar 12, the movement being guided by wheels 14 which run on the upper beams 7 of the formwork support assembly 3.

The carriage 11 carries a vertically-extending formwork support 15 which is supported by a diagonal brace 16. The formwork support 15 supports vertically oriented shuttering 17.

A pair of guard rails 18, 19 are provided, the lower guard rail 18 being fixed and positioned at the back of the slide-bar 12, extending between the terminal ends 8 of the upper beams 7. The upper guard rail 19 is provided spaced slightly behind the upper end of the shuttering 17 and will, as will become clear, move with the shuttering 17 and the carriage 11 as the carriage 11 moves along the slide-bar 12 and the upper beams 7.

Figure 2 illustrates the moving formwork arrangement 10 in a position in which it is spaced away from the building structure 2. During construction of the building structure 2, the formwork arrangement 10 is moved along the slide- bar 12 and the upper beams 7 so that it approaches the building structure 2 and adopts a position illustrated generally in Figure 3, in which the shuttering 17 extends substantially vertically above the tracks I which are secured to the ground-level part of the building structure. This is the position, illustrated in Figure 3, that the formwork adopts during the step of pouring the concrete, in order to form the subsequent stage of the building structure, on top of the first, ground level section, illustrated in Figures 2 and 3.

In the preferred embodiment illustrated, the tracks I each comprise a pair of elongate rails 20 which are arranged in close space-apart relation to one another, the respective rails 20 being spaced apart by spacers 21 arranged at points along their length. Each rail 20 has a generally C-shaped cross-section and the rails 20 of each length of track I are arranged in back-to-back relation such that the flanges 22 of one rail 20 extend outwardly away from the flanges 22 of the other rail 20. It should therefore be appreciated that the lengths of track I each have a pair of flanges which are spaced away from the building structure 2.

As also illustrated in Figure 4, each length of track I is provided with mounting pads 23 which extend outwardly from each side of the track I and which can be bolted or otherwise releasably affixed to the building structure 2.

Figure 4 also illustrates one of the primary support members 4 of the movable formwork support assembly 3 in more detail, and it can be seen here that the primary support member 4 also comprises a pair of spacedapart rails 24 arranged in back-to-back relation to one another, the rails 24 being substantially identical to the rails 20 of the track 1. Similarly, the upper beams 7 also comprise a pair of substantially identical, spaced-apart C-section rails.

Returning briefly to consider Figures 2 and 3, each primary support member 4 of the movable formwork support assembly 3 is provided with a pair of pivotally-mounted locking latches 25, located one above the other such that one of the latches 25 is located towards the upper region of each primary support member 4, and the other latch 25 is located towards the lower region of each respective primary support member 4. The configuration of the latches 25 will be explained in more detail hereinafter but, as shown in Figure 4, it should be appreciated at this time that the latches 25 are each located for pivotal movement between the rails 24 of each primary support member 4.

As illustrated most clearly in Figure 5, the primary support members 4 each carry a pair of guides 26, each guide 26 being positioned generally in the region of a respective locking latch 25. The guides 26 each comprise a plate 27 which extends across the rails 24 of the primary support member 4 and which extends outwardly, to each side of the support member 4. Bolted to the outwardly-projecting ends of the guider plate 27 are a pair of guide blocks 28, each of which extends past the immediately-adjacent flange 22 of the rails 20 defining the track 1. Extending inwardly from each guide block 28 is a respective guide shoe 29 which thus sits between the two flanges 22 of the rails 20 defining the track 1, and which therefore becomes located between the building structure 2 and the flange 22 of the track I spaced furthest from the building structure 2. It will therefore be seen that each said flange 22 is received within a guide space 30 defined between the guide shoe 29 and the guide plate 27.

Figure 6 illustrates the climbing formwork system of the present invention in the position adopted after the concrete for the first floor of the building has been poured into the space partially defined by the shuttering 17 when it adopted the position adopted in Figure 3. In this position, the movable formwork arrangement 10 has been moved away from the building structure 2 after the concrete has set, to allow additional lengths of track I to be secured to the most-recently formed, first floor, section of the building structure 2. The two additional lengths of track I are secured to the building structure 2 such that they lie coaxial with the respective lower sections of track I which are secured to the ground floor section of the building structure 2. In this way, the upper sections of track I form a continuation of the track.

As illustrated in Figure 7, the moving formwork arrangement 10 and its supporting assembly 3 can then be lifted as a single unit by, for example, a crane, as illustrated by arrow 31. In the arrangement illustrated in Figure 7, the wire 32 of the crane has been secured to the uppermost end of the formwork support 15, although it should be appreciated that the wire 32 could be secured to any convenient part of the formwork arrangement 10 or, indeed, any convenient part of the formwork support assembly 3. Indeed, in variants of the invention, the formwork support assembly 3 and the formwork arrangement 10 could be lifted from below by, for example, a hydraulic lifting arrangement or the like.

As the formwork arrangement is lifted, the locking latches 25 are caused to rotate and become unlocked from the tracks I in a manner which will be described in more detail hereinafter. As the latches 25 become unlocked, the support assembly 3 is no longer locked to the track I and instead the weight of the support assembly 3 and the formwork arrangement 10 is carried entirely by the lifting wire 32 of the crane. However, the guides 26 serve to guide the support assembly 3 along the track I as it is lifted and prevent the support assembly 3 from moving away from the building structure 2 as it is lifted.

Figure 9 illustrates the arrangement as the support assembly 3 reaches the end of the upper section of track 1, whereupon the locking latches 25 automatically lock the support assembly 3 with respect to the upper length of track I (in a manner which will be described in more detail hereinafter). The lifting wire 32 of the crane can then be removed and the support assembly 3 is left hanging from the upper length of track I at the appropriate position ready for the formwork arrangement 10 to be moved along the slide bar 12 towards the building structure to enable the concrete of the second floor section of the building structure to be poured.

Turning now to consider Figures 10 to 15, the operation of the locking latches will be described in more detail. In each of these drawings, one of the rails 20 of the track 1, and one of the rails 24 of the primary support member 4 have been removed for the sake of clarity.

As can be seen from, for example Figure 10, each rail 20 of the track I and each rail 24 of the primary support member 4 are provided with two vertically- running rows of equi-spaced holes. At predetermined positions along the length of the rails 20 defining the track I, support pins 33 are provided which extend between a respective hole in one of the rails 20 and a corresponding, aligned hole in the other rail 20. The support pins 33 are provided between the rows of holes spaced furthest from the building structure 2. The positions of the support pins 33 along the rails 20 defining the tracks I are most clearly illustrated in Figure 8.

The locking latches 25 are pivotally mounted about a pivot pin 34 which extends between the rails 24 defining the support members 4 in the same manner as the support means 33. The latches 25 are each therefore mounted for pivotal movement about a substantially horizontal axis defined by the longitudinal axis of the respective pivot pins 34.

At a point below its pivot, each locking latch 25 is provided with an arcuate slot which is centred on the axis of the corresponding pivot. Received within the arcuate slot 35 is a guide pin 36 which extends between aligned holes through the two rails 24 of the support member 4.

Extending downwardly and towards the track 1, each locking latch 25 is provided with a cam surface 37, and below this cam surface, on the underside of the latch 25, there is provided a locking notch 38 of a reentrant form.

Located generally below the arcuate slot 25, each locking latch 25 is provided with a downwardly-depending finger 39 which is of a size such that the finger 39 represents a significant proportion of the overall mass of the locking catch 25.

In the position illustrated in Figure 10, the finger 39 of the latch 25 bears against a stop 40 which extends between the two rails 24 and which is carried by the guide plate 27, thereby forming part of the guide 26.

As will be appreciated, because the finger 39 accounts for the significant proportion of the overall mass of the latch 25, and because the finger 39 extends downwardly towards one side of the pivot 34, the result is that the latches 25 are each biased, under the force of gravity, towards a respective position generally as illustrated in Figure 10, in which the finger 39 bears against the stop 40. It should be noted that in this position, the guide pin 36 does not actually bear against the end of the arcuate slot 35 within which it sits.

Figure 11 shows the situation in which the formwork arrangement of the present invention is lifted, as indicated by arrow 41, for example by a crane.

As will be appreciated, the rails 24 of the primary support member 4 move along the rails 20 of the track I until a point is reached, as illustrated in Figure 11, at which the cam surface 37 of the latch 25 bears against a support pin 33 carried by the track 1. The locking latch 25 is thus caused to rotate, in a clockwise sense as illustrated in Figure 11, against the gravitational bias imparted by the weight of the finger 39.

The latch 25 continues to rotate in this manner as the rails 24 continue to move along the rails 20, as illustrated in Figure 12, until a point is reached at which the latch 25 clears the support pin 33. At this instant, the weight of the finger 39 serves to return the locking latch 25, under the force of gravity, to its locking position illustrated in Figure 13, in which the forwardmost surface of the finger 39 bears against the stop 40. In this "locking position", illustrated in Figure 13, it will be seen that the notch 38 becomes located above the support pin 33 past which the latch 25 has just moved. The formwork support assembly 3 can then be lowered, such that the rails 24 slide a short way down the rails 20, guided by the guide 26, until the point is reached at which the support pin 33 becomes fully received within the notch 38 of the locking latch 35. The V-shape of the re-entrant notch 38 serves to slide the support pin 33 into the notch 38 as the assembly is lowered. When the lifting force provided by the crane is then removed, the latch 25 hangs on the support pin 33, and is prevented from rotating out of engagement by the support pin 33 due to the positive engagement between the finger 39 and the stop 40.

The two locking latches 25 provided one above the other on each primary support member 4 are spaced apart by a distance appropriate so that when the uppermost latch 25 engages a respective support pin 33, the lower latch engages a lower support pin 33 at exactly the same instant. In other words, if the support pins 33 are spaced apart from one another by a distance d running along the length of the track 1, then the vertical spacing between the two locking latches 25 of each primary support member 4 is equal to a x d, where a is an integer greater than zero. In the arrangement illustrated in Figures 8 and 9, the latches 25 are spaced apart by a distance equal to 3 d.

It will therefore be appreciated that, due to the configuration of the locking latches 25, and their relation to the support pins 33 and respective stops 40, the locking latches 25 each serve automatically to unlock from a respective support pin 33 as the formwork arrangement is lifted, and move past subsequent support pins 33 along the track I as the assembly is lifted, each time rotating back to their respective locking positions under the force of gravity so that the locking latches 25 automatically lock and hang from the support pins 33 as the formwork arrangement advances up the building structure.

It is usual when building tall structures using climbing formwork arrangements, to lift the formwork clear of the completed building, by lifting the formwork from the top of the track when the final level of the building structure has been completed. However, it is sometimes the case that a problem can occur during the construction process that may necessitate lowering the formwork to a previous level of construction. In order to facilitate easy lowering of the formwork of the present invention, it is envisaged that a hole 42 may be provided through the lower end of the finger 39 of each latch 25. It is proposed that these holes could be used to tie the latches 25 in a completely open position in which the latch is entirely clear of the support pins 33, for example using a lanyard or other convenient arrangement. It is envisaged that the crane would be affixed to the formwork arrangement, the entire assembly lifted such that all of the latches 25 become disengaged from their respective support pins 33, whereafter the latches 25 can each be manually rotated towards the position illustrated in Figure 12 and held there by tying a respective lanyard through the hole 42 which would therefore allow the entire assembly to be lowered back down the track I without the latches 25 automatically engaging the support pins 33 on the way down. When the formwork assembly has been lowered to the desired level, the lanyards can then be removed such that the latches 25 are allowed once more to swing under the force of gravity into their locking positions.

Whilst the present invention has been described above with reference to a particular embodiment, it is envisaged that certain modifications or alterations could be effected without departing from the scope of the present invention.

For example, it could be convenient to provide the support pins 33 in a manner in which they are selectively positionable, by a building contractor or user of the equipment, at positions along the length of the track I of the contractor or user's choice.

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

CLAIMS: 1. A climbing formwork system comprising: a substantially elongate

track and a moveable formwork support assembly; the track being releasably securable to a building structure such that the longitudinal axis of the track lies substantially vertically, and having a plurality of support formations at spaced- apart positions along its length; said support assembly being selectively moveable up the building structure along the track; wherein said support assembly carries at least one latch, the or each latch being pivotally mounted about a respective substantially horizontal axis and biased towards a locking position in which it engages a said support formation such that said support assembly can hang from the support formation, the or each latch having a cam surface configured to bear against the or each successive support formation so that the latch rotates out of said locking position thereby allowing passage of the latch past each successive support formation as the support assembly is moved up the track.
2. A climbing formwork system according to claim 1, wherein said support assembly is provided with a guide, the guide being configured to guide at least part of the track therethrough and retain the support assembly captive with respect to the track as the support assembly is moved up the track.
3. A climbing formwork system according to claim I or 2, wherein said latch is configured so as to be biased towards said locking position under the force of gravity.
4. A climbing formwork system according to claim 3, wherein said support assembly is provided with a stop against which part of said latch bears under gravity to define said locking position.
5. A climbing formwork system according to any preceding claim, wherein said latch has a notch to engage said support formations.
6. A climbing formwork system according to any preceding claim, wherein said track has at least one flange spaced from said building structure when the track is secured to the building structure.
7. A climbing formwork system according to claim 6, wherein said track comprises a pair of spaced apart elongate rails, each said rail defining a respective said flange.
8. A climbing formwork system according to claim 6 or 7 wherein said guide has a part which is located between said building structure and the or each said flange as the support structure moves along the track.
9. A climbing formwork system according to claim 8, wherein said guide comprises a guide shoe located between the building structure and the or each said flange.
10. A climbing formwork system according to claim 7, or either of claims 8 or 9 as dependent upon claim 7, wherein each said support formation takes the form of a pin extending between said spaced apart rails.
11. A climbing formwork system according to claim 10, wherein each rail is provided with a plurality of holes along its length, the holes of one rail being aligned with those of the other rail, and wherein said pins extend from respective holes in one of the rails to the aligned holes of the other rail.
12. A climbing formwork system according to claim 11, wherein said pins are selectively positionable between said rails.
13. A climbing formwork system according to any preceding claim, wherein said track is provided as a number of discreet lengths, each length of track being separately securable to the building structure and having at least one support formation.
14. A climbing formwork system according to claim 13, wherein each said length of track is provided with two support formations.
15. A climbing formwork system according to any preceding claim, wherein said support assembly comprises a pair of spaced-apart elongate rails, the or each said latch being pivotally mounted about a respective pivot extending between said rails.
16. A climbing formwork system according to claim 15 as dependent upon claim 4 wherein said stop extends between the two rails of the support assembly.
17. A climbing formwork system according to claim 15 as dependent upon claim 7, wherein the rails of the support assembly are substantially identical in cross-section to the rails of the track.
18. A climbing formwork system according to any preceding claim, wherein the support formations of the track are equi-spaced by a distance d, and wherein said support assembly carries two latches arranged one above the other, the axes about which the latches pivot being spaced-apart by a x d, where a is an integer greater than zero.
19. A climbing formwork system substantially as hereinbefore described with reference to and as shown in the accompanying drawings.
20. Any novel feature or combination of features disclosed herein.