| GB2338259B | 2002-03-27 | |||
| CA2574650A1 | 2008-07-19 | |||
| NL2003356C2 | 2011-02-15 | |||
| US20180080238A1 | 2018-03-22 | |||
| KR20170119996A | 2017-10-30 |
| Claims 1. A footer assembly for a formwork prop, said formwork prop suitable for use in supporting a concrete slab waler table or the like; said footer assembly being located between the base of said prop and the ground; said footer assembly being adapted to support said prop on a support member in a releasably engaged configuration; and further adapted to transition to a disengaged configuration, thereby to enable said support member to be lowered sufficiently to allow the removal from said prop from engagement with said waler table and said footer assembly. 2. The footer assembly of claim 1 , wherein said support member is supported in an engaged position by a strike wedge that is adapted to be removed in a horizontal direction, said removal thereby allowing said support member to be lowered and to allow said prop to be disengaged from said waler table and said footer assembly. 3. The footer assembly of claim 2, wherein said strike wedge is a ring-shaped member having a central hole that has distinct zones of differing width; and wherein said zones may be defined as an engagement zone and a disengagement zone; said engagement zone having a width that is less than the width of said support member; and wherein said disengagement zone has a width that is greater than the width of said support member, thereby allowing said support member to pass through said strike wedge. 4. The footer assembly of claim 3, wherein said strike wedge is secured in place in an engaged position by a locking collar located around said support member, said locking collar having an appendage adapted to prevent horizontal movement of said strike wedge toward a disengaged position. 5. The footer assembly of claim 4, wherein said locking collar is adapted to be disengaged from said strike wedge by sliding movement of said collar upward away from said strike wedge. 6. A method of installing a formwork prop for use in supporting a concrete slab waler table or the like; said method including the step of placing said prop in an engaged position on a footer assembly according to any preceding claim. 7. The method of claim 6, wherein in said engaged position, said engagement zone is operably engaged with said support member and is said disengaged position, said disengagement zone is located around said engagement member. 8. A method of removing a formwork prop from supporting a concrete slab waler table or the like, whereon said prop is supported on a footer assembly in accordance with claim 5; said method including the steps of: raising said locking collar; and applying a horizontal force to said strike wedge thereby to cause the wedge to slide from an engaged position to a disengaged position; whereupon said support member is allowed to lower sufficiently to allow said prop to be disengaged form said footer assembly and said waler table, or the like. |
Technical Field
[0001] The invention relates to the field of shoring equipment for concrete platform formwork. In particular, the invention relates to an improved footer for a shoring prop and a method of installing and removing same.
Background of the Invention
[0002] The construction of large modern buildings usually involves the pouring of elevated concrete slabs or beams. There are a wide variety of concrete formwork systems, depending on the style of the building and other prevailing conditions at the location.
[0003] In some constructions, during pouring and setting of the concrete, such beams are formed from solid tables that act as the ‘mould’ for the concrete. These tables are typically supported by a set of parallel cross joists. The joists are in turn supported by two or more waler beams that run perpendicular to the joists.
[0004] The waler beams will usually be supported by some form of shoring. This shoring may take the form of a relatively complicated cross braced formation. However, it may be preferred to support the waler beam with a set of simple height-adjustable props. An example of such a prop is that marketed by PERI GmbH of Weissenhorn Germany under the name ‘Multiprop’ and as illustrated in Figure 1 . An advantage of these type of props is that they are readily height adjustable, easy to transport and can be simpler to install than more complicated shoring.
[0005] Typically, these props will stand directly on the ground and be anchored to the waler beams above. Removal of such beams, after the slab is set and no longer requires such ancillary support, requires disengagement of the anchor mechanism in contact with the waler beam and a swinging or sliding removal action of the prop. This requires the formworker to access the top of the beam to effect the disengagement and may require substantial clearance around the beam for the removal motion of the beam to be effected.
[0006] This in turn may cause difficulties in the removal process due to the requirement for the operator to work at substantial height; and for the heavy prop to be moved in a manner that is difficult to perform safely by a single operator and which may be restricted by the available space. This can lead to safety hazards in both operations and will require a greater number of formworkers to complete the task.
[0007] Accordingly, it is an object of the invention to provide a that ameliorates at least some of the problems associated with the prior art.
Summary of the Invention
[0008] According to a first aspect of the invention, there is provided a footer assembly for a formwork prop, said formwork prop suitable for use in supporting a concrete slab waler table or the like; said footer assembly being located between the base of said prop and the ground; said footer assembly being adapted to support said prop on a support member in a releasably engaged configuration; and further adapted to transition to a disengaged configuration, thereby to enable said formwork prop to be lowered sufficiently to allow the removal from said prop from engagement with said waler table.
[0009] Preferably, said support member is supported in an engaged position by a strike wedge that is adapted to be removed in a horizontal direction, thereby allowing said support member to be lowered and disengage form said prop.
[0010] Such an assembly greatly simplifies the process of removal of the prop once the slab has set. An operator simply moves the strike wedge into a disengaged position and the support member will drop a small, predetermined distance, for example approximately 20mm, sufficient to allow the prop to be removed without employing the disengagement actions known in the prior art.
[0011 ] The footer assembly works particularly well where a prop headed allows for an operator standing at ground level to disengage the prop head. This eliminates all need for the operator to be elevated above the ground to remove the prop, which improves the efficiency and safety of the removal operation.
[0012] Preferably, said strike wedge is an O-shaped member having a mouth that has distinct zones of differing width; and wherein said zones may be defined as an engagement zone and a disengagement zone; said engagement zone having a width that is less than the width of said support member; and wherein said disengagement zone has a width that is greater than the width of said support member.
[0013] The invention represents a simple and mechanically reliable means to achieve the release of the prop: the strike wedge has only to be moved to a position where the wider part of the mouth is below the support member, thereby allowing the member to slip downward through the mouth, thereby releasing the prop foot.
[0014] Preferably, said strike wedge is secured in place in an engaged position by a locking collar located around said support member, said locking collar having an appendage adapted to prevent horizontal movement of said strike wedge toward a disengaged position. This is a reliable device adapted to prevent accidental dislodgement of the strike wedge, while allowing simple unlocking of the strike wedge when it is desired to remove the prop.
[0015] Preferably, said locking collar is adapted to be disengaged from said strike wedge by sliding movement of said collar upward away from said strike wedge.
[0016] According to another aspect of the invention, there is disclosed a method of installing a formwork prop for use in supporting a concrete slab waler table or the like; said method including the step of placing said prop in an engaged position on a footer assembly according to that described above.
[0017] According to another aspect of the invention, there is disclosed a method of removing a formwork prop from supporting a concrete slab waler table or the like, wherein said prop is supported on a footer assembly in accordance with any described above; said method including the steps of: raising said locking collar; and applying a horizontal force to said strike wedge thereby to cause the wedge to slide from an engaged position to a disengaged position; whereupon said support member is allowed to lower sufficiently to allow said prop to be disengaged form said waler table or the like.
[0018] In said engaged position, said engagement zone is operably engaged with said support member and is said disengaged position, said disengagement zone is located around said engagement member.
[0019] Now will be described, by way of a specific, non-limiting example, a preferred embodiment of the invention with reference to the drawings.
Brief Description of the Drawings
[0020] Figure 1 is a drawing of a PERI Multiprop formwork prop of the type that is compatible with the invention. [0021] Figure 2 is a drawing of a formwork table installation of a type with which the invention may be used.
[0022] Figure 3 is a lateral view of a footer assembly according to the invention.
[0023] Figure 4 is a front view of a footer assembly according to the invention.
[0024] Figure 5 is a plan view of a footer assembly according to the invention.
[0025] Figure 6 shows a lateral view of a support member for a footer assembly according to the invention.
[0026] Figure 7 shows a front view of a support member for a footer assembly according to the invention.
[0027] Figure 8 shows a plan view of a support member for a footer assembly according to the invention.
[0028] Figure 9 shows side and front views of prop clip for a footer assembly according to the invention.
[0029] Figure 10 shows a locking collar for a footer assembly according to the invention.
[0030] Figure 11 shows a strike wedge for a footer assembly according to the invention.
[0031 ] Figure 12 shows a prop and footer assembly in use prior to disengagement.
Detailed Description of the Invention
[0032] A particular type of formwork shoring for pouring of concrete slabs involves supporting a formwork table, which acts as a mould for the concrete, on a set of crossbeams. The crossbeams are in turn supported by two or more laterally arranged waler beams. The waler beams are supported by props and are secured to the props via a prop head. In the prior art, the lower end of said props typically sit directly on the ground.
[0033] The invention may be characterised as an assembly, upon which the foot of the prop can rest, that is adapted to allow the easy lowering of then prop by a short distance, that enables the simple removal of the prop when desired. In particular, the invention provides a design for same that is robust, reliable to operate and not expensive to manufacture.
[0034] Turning to figure 1 , there is shown a prop of the type described above. This is an example of a PERI Multiprop MP 350 prop as supplied by PERI GmbH of Weissenhorn, Germany. The prop 5 has an extendable stem 10 and a foot plate 15. The foot plate 15 is a steel plate of approximately 150mm x 150mm.
[0035] In the description below, this type of prop will be used as an example of the type of prop that the present invention can be used in conjunction with. However, those skilled in the art will understand that the inventive concept is not limited to this one type of prop and that the concept may be extended to a variety of other prop designs.
[0036] Turning to figure 2, there can be seen an elevated formwork system incorporating such props. Several props 15 are shown connected to one or more waler beams 20. Across the waler beams 20 are laid several crossbeams 25. The cross beams 25 in turn support the formwork table 30, upon which the concrete 31 is poured. The prop heads 32 are located at the top of the props 15, where they are connected to the waler beams 20. The prop footers 35 are located at the foot of the props and they rest directly on the ground.
[0037] Turning to figures 3, 4 and 5, the prop footers are shown in greater detail. The main parts of the footer are: the sub-base plate 40; the prop foot support 45 incorporating the prop clip 50 and the prop foot plate 55; the strike wedge 60 and the wedge locking collar 65.
[0038] The prop foot support 45 engages with the foot plate of the prop - the prop sits on the prop foot plate 55 and the clip 50 inserts into the prop. The lower stem of the prop support sits on the sub-base plate 40 and inside the base plate collar 70.
[0039] In an engaged position while supporting the prop, the strike wedge 60 sits on the base plate collar 70 and the support member at least partially rests on the strike wedge 60.
[0040] T urning to figures 6, 7 and 8, there is shown more detail of the prop foot support 45. The prop foot plate 55, typically steel, is attached to the top of the stem 75. The stem 75 is a hollow square steel section that has slots 80 extending upward from its lower end in two opposing faces. Steel side plates (85, 90) are welded to the outside of the stem 75 and extend from the upper end to midway down the stem. The lower edges (95, 100) of these side plates are adapted to rest on the strike wedge 60.
[0041 ] The clip assembly 50 is welded to the upper side of the prop foot plate 55. The clip assembly consists of the clip loop 105 and a spring-loaded snib 110.
[0042] The snib 110 is shown in more detail in figure 9. It is made from steel plate and has a hole at a top end 115 that allows it to be pivoted to the loop 105. The lower end of the snib has teeth 120 that allow it to engage with a complementary opening in the side of the prop 15, and an elongated finger 125 that can be engaged to release the clip when desired.
[0043] Turning to figure 10, there is shown the locking collar 65 in more detail. It consists of the collar ring 130 that is sized to fit slidably around the stem 75 of the prop support 45. It has an L-shaped locking arm 135 that extends from the outside of the ring 130 and is adapted to fit over and secure the strike wedge 60. It also has a raising handle 140 that extends from a different side of the ring 130 and is adapted to allow the operator to lift the locking collar upward and out of engagement with the strike wedge 60.
[0044] Turning to figure 11 , there is shown greater detail of the strike wedge 60. The strike wedge 60 is essentially an O-shaped member that consists of an outer ring 145 and a central mouth 150. The central mouth 150 has two distinct sections: a wider section 155 that is sized to allow the stem 75 of the support member 45 to pass through when the footer is disengaged; and a narrower section 160 that is sized to engage with the plates (85, 90) attached to the stem 75 when in an engaged position.
[0045] When the strike wedge 60 is in an engaged position, the side plates (85, 90) attached to the stem 75 sit on the edges of the narrower part 160 of the mouth 150 and are supported thereby. When in a disengaged position, the strike wedge 60 is moved laterally such that the narrower section 160 gives way to the wider section 155 and the stem 75 and plates (85, 90) are enabled to pass through. This causes the prop footer plate 55 to be lowered by a distance equivalent to the thickness of the strike wedge, which is sufficient to allow the prop to be removed with relative ease compared with the prior art.
[0046] Turning to figure 12, there is shown the prop footer assembly 35 in situ in an engaged position. The footer is installed with the strike wedge in an engaged position as shown. [0047] When the prop is to be removed, the locking collar 65 is moved upward to unlock the strike wedge 60. A force is applied to the end of the strike wedge 60 adjacent to the wider mouth section 155 in the direction of the arrow A, thereby to push the strike wedge 60 out of the engaged position and into a disengaged position, where the whole stem 75 of the support member can drop through the wider section 155 and thereby allow the lower the prop footer plate 55, and hence the top of the prop 15, to be moved away from the header assembly.
[0048] The clip 50 can then be disengaged by moving the snib 110 inwards in the direction of the arrow B and the prop can easily be removed from the footer assembly.
[0049] It will be appreciated by those skilled in the art that the above-described embodiment is merely one example of how the inventive concept can be implemented. It will be understood that other embodiments may be conceived that, while differing in their detail, nevertheless fall within the same inventive concept and represent the same invention.