AU2003200226A1 - Reinforcement supports and their installation - Google Patents

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Applicant(s): EZYCHAIR PTY LTD A.C.N. 094 264 918 Invention Title: REINFORCEMENT SUPPORTS AND THEIR INSTALLATION The following statement is a full description of this invention, including the best method of performing it known to me/us: 2 REINFORCEMENT SUPPORTS AND THEIR INSTALLATION The present invention relates to supports for and installation of supports for reinforcement steel used in concrete slabs such as those used for floors in building construction for buildings, roadways, paths and the like.

Such concrete slabs include those placed on a prepared foundation such as an excavated building site as well as those to be formed over formwork for upper floors on a multi-storey construction. In either case reinforcement steel must be correctly positioned and supported to meet the requirements of being located a defined distance from the concrete surface when finished.

This is important to provide coverage to prevent corrosion as well as to provide the specified strength to the slab to meet engineering requirements.

Conventional practice is to use spacers which support reinforcement steel which can be of a preformed mesh form or alternatively bars, the spacers typically being of moulded plastics material or formed from steel with legs having tips coated with corrosion resistant material.

Such spacers are typically known as and are in the form of "chairs". A typical installation is to drop the steel reinforcement into the approximate required position.

When a steel mesh is used it may be many metres long and several metres wide and a panel of such mesh has flexibility, is heavy and awkward to handle.

Conventionally a support chair is manually inserted at spaced intervals to support such a mesh or reinforcement bar of prescribed distance above the base surface for the concrete slab. The placement of such spacers, especially for reinforcement mesh, is a laborious task which also is somewhat time-consuming. There is also a risk of injury to workers and in particular back strains due to the stress of lifting reinforcement steel while positioning the spacer accurately under the reinforcement steel so that when the steel lowered it is correctly supported.

3 The present invention is directed to a system which facilitates the installation of supports for such reinforcement steel.

According to a first aspect of the present invention, there is provided a support for reinforcing steel in a concrete slab structure, the support comprising a generally hollow nestable body having a base for engaging and facilitating sliding motion across a support surface, spaced upstanding side walls extending from the base, an upper portion having engagement means for engaging and supporting an elongate reinforcing element for the concrete when lowered into the engagement means, the support being apertured to admit concrete into the interior of the support so that the support is intimately bonded into the concrete structure and the sidewalls including an inclined upwardly extending face over which the reinforcing element may be moved as it is lifted by a support installing device and as the support is moved over the support surface in a direction substantially at right angles to the direction of elongation of the reinforcing element to the correct location, the support being such that the reinforcing element can then be dropped into the engagement means.

Particularly to suit a preferred form of applicator which is a second aspect of the present invention, the support preferably has, in plan view a T-shaped aperture so that a nested stack of supports can be engaged on a Tshaped column of the applicator.

Preferably apertures are provided in the support walls and the ends of the support are also open to admit concrete.

Preferably the base of the support comprises a pair of strip-like feet and the engagement means is a notch having an axis extending at right angles to the direction of elongation of the feet, the side walls being generally planer and extending upwardly from the feet and being inclined towards one another with each side wall having an 4 outwardly extending shoulder to support the feet of the next support element above it in a nested stack.

The inclined face is preferably provided at an end face of each side wall to be in the nature of a ramp up which the reinforcing steel element can move during installation. Preferably the support is symmetrical so that both ends of the side will have such ramps to facilitate a nested stack being installed, for convenience, with either end face of the walls the leading end.

Preferably the support is an injection moulding plastics product and may incorporate further features described hereinafter with reference to the drawings and a preferred embodiment.

A second aspect of the invention concerns an applicator for installing supports according to the first aspect of the invention, the applicator having means for holding a nested stack of supports, a foot element for supporting the applicator on the surface above which reinforcing steel is to be mounted, an upstanding structure having an element for retaining the nested stack of spacers for relative vertical movement and dispensing, a pivotal actuating handle adapted to be pivotally relative to the upstanding structure to pivotally displace upwardly a reinforcing engagement element whereby the steel is moved upwardly adjacent the inclined leading face of walls of the lowermost support, and the applicator having a displacement element actuated responsive to the handle movement such that when the reinforcing engagement element has been lifted, the upstanding structure is displaced towards the reinforcing whereby the nested stack of spacers is moved forwardly and the reinforcing engages under and supports the second spacer in the stack whereby the lowermost spacer is free to be moved into the correct position with its engagement means underneath the reinforcing element which may then be dropped into position by reverse motion of the handle, the applicator 5 further having means for withdrawing the upstanding structure and the remaining nested stack of spacers so that, when the base of the new lowermost spacer is free from support by the reinforcing, the spacer stack is dropped to be supported on the foot element.

The applicator with advantage which can incorporate further inventive features described hereinafter in exemplary form with reference to the accompanying drawings.

In our third aspect the invention may be defined as being applicable to a method of installing reinforcing steel in the concrete slab wherein spacers accordingly to a first aspect of the invention are installed using an applicator in accordance with the second aspect of the invention.

In a fourth aspect the invention extends to a concrete slab structure formed using the spacers described above and/or the method described above.

Although the support according to the first aspect of the invention will be exemplified with reference to the preferred and most convenient installation method, namely using an applicator according to the second aspect of the invention, the support itself may also be used without such an applicator. For example installation could be by individual positioning whether from a nested stack or otherwise adjacent to the required location for installation against elements eg of a reinforcing mesh with the worker using a separate manually operated lifting device (such as a lever) which can be operated from a substantially upright position to lift the mesh while the workers foot is used to displace the support laterally to the correct position at which point the reinforcing mesh is released to be supported.

The invention can be further described with reference to the accompanying drawings which exemplify a preferred embodiment and wherein; Figure 1 is a perspective view of a plastic support 6 chair embodying the invention; Figure 2 is a front view of the chair at figure 1, the rear view being identical as the illustrated chair is symmetrical; Figure 3 is a side view of the chair of figure 1; Figure 4 is a plan view of the chair of figure 1; Figure 5 is an inverted plan view of the chair of figure 1; Figure 6 is a front view illustrating a nested stack of the chairs of figure 1; Figure 7 is a side view of the nested stack of chairs; Figure 8 is a side view of an applicator device embodying the invention and having a stack of some five chairs and ready for use; Figure 9 is a front view of the applicator; Figure 10 is a rear view of the applicator; Figure 11 is an inverted plan view of the applicator; Figure 12 is a plan view of the applicator; Figure 13 is a rear view of the applicator with the handle removed to show other parts more clearly; Figures 14-21 show on an enlarged scale the use of the applicator and installation under a reinforcing steel bar which is part of a typical reinforcing mesh.

Referring first to figures 1-5, the support chair illustrated is adapted to be injection moulding in a suitable structural plastics material. The chair 10 is symmetrical and has an elongate foot 11 at each side with upstanding sidewalls 12 which converge towards one another and which are interconnected at the frontand rear by transverse bridges 13. There is a reinforcement steel receiving notch 14 defined between the bridges. The lower portion of each wall has an aperture 15, the whole structure being essentially hollow whereby after installation concrete can flow into the interior to form an integrated structure with the chair embedded in the concrete. At the ends of each aperture 15 an exterior 7 elbow element 16 is provided and integrally formed with the foot 11 and sidewall 12 with the upper surface of the elbow element defining a shoulder 17. As will be best seen from figures 6 and 7 the shoulder 17 acts to support the foot 11 of the next chair above in a nested stack.

At the front and rear ends the sidewalls have corresponding ramp surfaces 18 so there is symmetry and either can be used as the leading surface during installation.

Each bridge element 13 incorporates inclined sidewalls 19 which follow the contour of the end-face 18 of each sidewall. There are lower end wall portions which are vertical and space and strengthen the structure, leaving a T-shaped slot 21 in plan view.

Referring now to figures 9-13, the applicator device will now be described.

The applicator comprises an upstanding mast 31 having a gripping handle 32 and an outwardly pivotal handle 33 pivotally mounted at a lower portion of the structure via transverse pivot pin 41.

A bracket 45 is fixed to the rear of the mast 31 and mounts via a pivot pin 46 a generally L-shaped foot 44 so that the mast 31 can pivot about the pin 46 in a clockwise direction as seen in side view during installation as described below; the mast 31 also mounts a bolt on which a helical compression spring 47 is secured, the spring being compressed during clockwise rotation of the mast 31 to provide a returning force.

A frame 48 is secured to the mast near its lower region and this in turn mounts a bracket 40 on which the transverse pivot pin 41 mounts the handle 33. A tension spring 42 is connected between a bottom portion of the handle 33 and the frame 40 so as to urge the handle 33 towards the mast 31. When the handle 33 is moved clockwise as shown in figure 1, the frame 40 moves with the handle so that its forward ends move upwardly as described in more detail below to lift a connecting link 8 44, which is pivotally connected at 15 to the frame and, at its lower end, pivotally connected at 18 to a side plate of a respective lifter prong 46.

A link 43 is rigidly connected to the frame 40 and has a flat tip portion which engages in a vertical slot 42 best shown in figure 13, an end portion extending laterally to retain the link in the slot. This permits relative motion between the handle 33 and the foot 44.

Figure 13 also illustrates a vertical slot 41 for accommodating the bolt on which return spring 47 is mounted to permit arcuate movement of the handle relative to the foot 44.

As most clearly seen from figure 13, the prongs 46 lie laterally outside the central part of the applicator and outside the location of a generally U-shaped bail 49 which attached to a lower portion of the mast and acts as a guide, as will be described in more detail below. The bail 49 extends around the stack of nested chairs.

As can be seen from figure 12, in plan view the chairs are as illustrated in figures 1-5 and the mast has a T-shaped spine which engages in a T-shaped aperture 21 of each chair so they are vertically slideable as a stack.

Operation of the applicator and a fuller understanding of its construction will now be given with reference to figures 14-21 which explain a cycle of operations.

As shown in figure 14, the foot 44 is placed on a support surface 60 and the applicator slid forwardly to engage the leading tips of the prongs 46 under an elongate reinforcing steel element 43 such as an element in a reinforcing mesh panel. The operating handle 33 is then manually displaced in a clockwise direction away from the mast 31 so that, as shown in figure 15, the prongs 46 are rotated by the handle and the return spring 42 is extended, the reinforcing steel being lifted upwardly behind the bail 49. The steel is thus displaced upwardly over the inclined leading edge 18 of the lower most chair.

9- Continued motion, as shown in figure 16 shows the support 44 firmly engaging the surface 60 and bearing the weight of the applicator and some weight from the reinforcing steel 43. The mast as shown in figure 6 has moved about pivot pin 46 relative to the foot 44 and the reinforcing steel element 43 engages under and lifts all the upper chairs in the stack. Motion is continued until the configuration of figure 17 is reached by which time the compression spring 47 has been fully compressed, the tension spring 42 fully extended and the reinforcing steel 43 is at its maximum elevation and ready to be dropped.

Figure 18 shows the situation after reverse action of the handle 43 has commenced by it being released and the steel moves down the notch 14 to be supported. Figure 19 shows the operating handle 43 returning towards the mast and at this point the relative rotation between the foot 44 and the mast 41 is at its maximum. Figure 20 shows the effect of the operator using the handle to move the applicator re-wardly but with the reinforcing element 43 still supporting the remaining stack of chairs until the position in figure 21 is achieved with the operator lifting the applicator so that the chairs are released to drop down onto the foot 44.

Claims (11)

1.A support for reinforcing steel in a concrete slab structure, the support comprising a generally hollow nestable body having a base for engaging and facilitating sliding motion across a support surface, spaced upstanding side walls extending from the base, an upper portion having engagement means for engaging and supporting an elongate reinforcing element for the concrete when lowered into the engagement means, the support being apertured to admit concrete into the interior of the support so that the support is intimately bonded into the concrete structure and the side walls including an inclined upwardly extending face over which the reinforcing element may be moved as it is lifted by a support installing device and as the support is moved over the support surface in a direction substantially at right angles to the direction of elongation of the reinforcing element to the correct location, the support being such that the reinforcing element can then be dropped into the engagement means.

2. A support as claimed in claim 1 above and wherein the support has, in plan view a T-shaped aperture so that a nested stack of supports can be engaged on a T-shaped column of the applicator.

3.A support as claimed in claim 1 or claim 2 and wherein apertures are provided in the support walls and the ends of the support are also open to admit concrete.

4.A support as claimed in any one of the above claims and wherein the base of the support comprises a pair of strip- like feet and the engagement means is a notch having an axis extending at right angles to the direction of elongation of the feet, the side walls being generally planer and extending upwardly from the feet and being inclined towards one another with each side wall having an outwardly extending shoulder to support the feet of the next support element above it in a nested stack. 11 A support as claimed in any one of the preceding claims wherein the inclined face is provided at an end face of each side wall to be in the nature of a ramp up which the reinforcing steel element can move during installation.

6.A support as claimed in claim 5 wherein the support is symmetrical so that both ends of the side will have such ramps to facilitate a nested stack being installed, for convenience, with either end face of the walls the leading end.

7.A support as claimed in any one of the preceding claims in the form of an injection moulded plastics product the support.is an injection moulding plastics product and may incorporate further features described hereinafter with reference to the drawings and a preferred embodiment.

8.A support substantially as herein described with reference to the accompanying drawings.

9.An applicator for installing supports according to any one of the preceding claims, the applicator having means for holding a nested stack of supports, a foot element for supporting the applicator on the surface above which reinforcing steel is to be mounted, an upstanding structure having an element for retaining the nested stack of spacers for relative vertical movement and dispensing, a pivotal actuating handle adapted to be pivotally relative to the upstanding structure to pivotally displace upwardly a reinforcing engagement element whereby the steel is moved upwardly adjacent the inclined leading face of walls of the lowermost support, and the applicator having a displacement element actuated responsive to the handle movement such that when the reinforcing engagement element has been lifted, the upstanding structure is displaced towards the reinforcing whereby the nested stack of spacers is moved forwardly and the reinforcing engages under an supports the second spacer in the stack whereby the lowermost spacer is free to be moved into the correct position with its engagement means underneath the reinforcing element which may then be dropped into 12 position by reverse motion of the handle, the applicator further having means for withdrawing the upstanding structure and the remaining nested stack of spacers so that, when the base of the new lowermost spacer is free from support y the reinforcing, the spacer stack is dropped to be supported on the foot element. An applicator substantially as herein described with reference to the accompanying drawings.

11. A method of installing reinforcing steel in the wherein spacers accordingly to any one of claims 1-8 aspect of the invention are installed using an applicator in accordance with claim 9 or

12. A- method of installing reinforcing steel substantially as herein described with reference to the accompanying drawings.

13. A concrete slab having reinforcing positioned and supported using a support as claimed in any one claims 1-8 and/or using an applicator as claimed in claim 9 or claim or using the method of claim 11 or claim 12.