DESCRIPTION OF THE DRAWINGS
Some preferred forms of the invention will now be described by way of example and with reference to the accompanying drawings, of which:
FIG. 1 is a transverse cross section view of a concrete crack controller,
FIG. 2 is a side view of the crack controller of FIG. 1,
FIG. 3 is a plan view of the crack controller of FIGS. 1 and 2,
FIG. 4 is a perspective view of an alternative concrete crack controller,
FIG. 5 is an end view of the crack controller of FIG. 4,
FIG. 6 is a transverse cross section view of a straight line connector,
FIGS. 7 and 8 are a side and plan view respectively of a four way connector,
FIGS. 9 and 10 are a side and plan view respectively of a three way connector,
FIGS. 11 and 12 are a side and plan view respectively of a two way angled connector, and
FIGS. 13 and 14 are a side and plan view respectively of a three way T connector,
FIGS. 15 to 18 are perspective and end elevation views of alternative concrete crack controllers.
DETAILED DESCRIPTION
Referring to FIGS. 1, 2 and 3, the concrete crack controller 1 is an elongate section having a base 2 with two elongate side walls 3 and 4 angling upwards from the base to meet one another. The controller 1 is thus hollow and generally triangular in transverse cross section. The side walls 3 and 4 have a series of spaced elongate apertures 5 as shown in FIGS. 2 and 3. As can be seen, the base 2 extends slightly either side of the walls 3 and 4, and the apex of the walls has a vertical extension 6.
When the controller 1 is in use it may be placed base 2 down and a volume of concrete is poured around it. The concrete at least substantially covers the controller 1 and, by way of the apertures 5, passes therethrough. Steel reinforcing (not shown) can also be passed through the apertures 5 if desired. As the concrete sets it tends to crack at or in the vicinity of the controller 1. This controlled cracking may be facilitated by the fact that the body of concrete either side of the controller may have substantially greater mass than the controller and/or the portion of concrete which passes through the controller.
FIGS. 4 and 5 show an alternative concrete crack controller 7 which has a base 8 and an upwardly extending wall 9. The base and the wall are substantially in an inverted “T” shape. As shown, the controller 7 has a series of spaced elongate apertures 10. The alternative crack controller 7 is used to control concrete cracks in much the same way as that mentioned previously, that is it is placed base 8 down and concrete is poured around and through it. Reinforcing steel may also be passed through the apertures 10. Cracks which form in the concrete tend to occur at or in the vicinity of the controller 7 given that it creates a line or lines of weakness in the concrete.
Preferably the controllers 1 and 7 each have small apertures in their base 2 or 8 to enable it to be fixed to an underlying surface if desired. Preferably these bases 2 and 8 are substantially flat so that the controllers 1 and 7 can be more readily leveled if need be.
In the case of the first mentioned controller 1 the triangular shape formed by the walls 3 and 4 and the underlying portion of the base 2 give a measure of strength and stability—eg to resist undesired lateral movement of the walls.
The controllers 1 and 7 may be formed from any suitable material, for example from steel, plastics, or resinous materials generally.
When the controllers 1 and 7 are in use it will in certain instances be desirable to connect them to other such controllers 1 and 7 respectively. To achieve this they may be used with suitable straight line, angle, or “T” joints as needed. FIG. 6 shows a straight line connector 11 which can be used to join two of the first mentioned controllers 1. More specifically, two crack controllers 1 may fit onto the connector 11 as a sleeve, each at an opposite end of the connector 11. The connector 11 may have a lip 12 at each end to restrict the extent to which it can fit inside the crack controllers 1.
FIGS. 7 and 8, FIGS. 9 and 10, FIGS. 11 and 12, and FIGS. 13 and 14, show various other connectors which may be used with crack controllers 1 as described with reference to FIGS. 1, 2 and 3. In each case the crack controllers 1 fit as a sleeve onto the connectors. Preferably each of these connectors has an aperture or apertures so that concrete or the like can enter inside and/or through them.
Optionally the crack controllers 1 and 7 and the various connectors described above are formed from 2.0-3.5 mm (or preferably from 2.5-3.0 mm) gauge steel or plastics. The gauge of material used may be selected to match a desired expansion joint size.
Preferably the apertures 5 and 10 in the crack controllers account for approximately 50% or more of the side walls, and more preferably 52% of these.
It will be appreciated that at least some embodiments of the invention enable one to create controlled expansion joints in a body of concrete or the like. The joints may correspond to the positioning of the crack controller beneath the surface of the concrete.
FIGS. 15, 16, 17 and 18, show crack controllers 13, 14, 15, and 16 in accordance with alternative embodiments of the invention. Each figure shows the respective crack controller 13, 14, 15 or 16 in both end elevation and perspective. Each of the crack controllers 13-16 are adapted for various applications, for example for the corners of concrete wall panels to control cracking therein, or to control cracking at floor level. Concrete may be applied to the controllers 13-16 by way of a spray method or any other suitable means.
As shown in FIGS. 15, 16 and 18, the controllers 13, 14 and 16 each have two V shaped end portions and an intermediate connecting wall portion. The wall portions have apertures to enable concrete or some other cementitious material to pass therethrough. In the case of controllers 13 and 14 the apexes of the two V shaped end portions are oriented in the same direction and are connected to their wall portion at their apexes, either at the internal or external part of the apexes as the case may be. In the case of the controller 16 the apexes of the two V shaped portions are oriented away from one another and are interconnected by their wall portion at the internal parts of such apexes. As shown in FIG. 17 the controller 15 is in the form of a right angle, one arm of the angle being a base portion, and the other being a wall portion having apertures therein. Preferably with all of the controllers 13-16 the apertures thereof make up at least substantially 50% of the surface area of the wall portion in each case.
While some preferred forms of the invention have been described by way of example it should appreciated that modifications and improvements can occur without departing from the scope of the appended claims.
Patent Application
20080022622
