Field of the Invention

This invention relates to a repair of cementitious structures, particularly to a system for repairing holes, damage and vertical, horizontal and diagonal cracks to vertical or near vertical concrete walls.

Background to the Invention

Currently on the market there are a variety of two component structural resin products for reinstating structural strength. These can be supplied in two component cartridges designed to be used with a twin piston skeleton gun. The cartridges include a static mixing head which is attached to a nipple, ball packers etc, into which the resin is injected. This process normally takes around three days which is a major drawback in terms of both expense and time. The resin products are formulated to be injected into cracks which appear in concrete structures over time or in adverse situations, such as after ground movement in earthquakes. The cracks or damage if left un-repaired are not watertight and the steel reinforcing in the concrete is exposed with the resultant weakness over time. This is caused by rust and exposure to weather conditions.

The applicant's system does not require ball packers etc and injects the resin directly into a prepared crack.

Further advantages of the invention will become apparent from the following description which is given by way of example only. Object of the Invention

It is therefore an object of the invention to provide a system for the repair of cracks in concrete walls or to at least provide the public with a useful choice.

Summary of the Invention

According to a first aspect of the invention a rigid tubular member is adapted to fit over a static mixer of a cartridge, which prevents the static mixer from bending or being distorted when resin is being injected under pressure.

The rigid tubular member may be constructed from any suitable rigid material such as steel or the like. It could also be adapted to fit over the static mixer by inserts at either end thereof.

According to a second aspect of the invention, a rubber gasket adapted for insertion on the end of a static mixer of a resin cartridge is applied. This gasket rests firmly on a rigid tubular member on the static mixer so pressure is maintained to provide a seal between the static mixer, and concrete without distorting or bending the static mixer when it is used.

The rubber gasket may be manufactured with internal or external ribs to provide rigidity. It may be manufactured from polyvinyl chloride or the like material.

The rigid tubular member may be straight or curved in shape. The curvature of the stiffener may vary between about 60 and 100 degrees. More preferably the curvature range is 60-80 degrees and more preferably is about 80 degrees.

The length of the stiffener is at least partly determined by the length of the static mixer.

The curved or arched stiffener is designed for spaces where the straight stiffener cannot fit. This may either be for tight corners and/or where there is an obstruction such as, for example, warehouse shelving. The method of the applicant's system involves the following process: fitting a two-pot resin cartridge to a skeleton gun; fitting a static mixer head to the resin cartridge in the skeleton gun; fitting a rigid tube over the static mixer to provide rigidity thereto; fitting a rubber gasket on the static mixer that extends past the rigid tube; pressing the rubber gasket to the hole, crack or damage; injecting under pressure the two-pot resin through the static mixer and rubber gasket to thereby fill the hole, crack or damage; the exposed resin in the hole, crack or damage is sealed by wax while the resin sets or hardens.

The invention also provides a system for the injection of resin into cracks in concrete in walls comprising a rigid tubular member adapted to enclose a static mixer and including an insert at each of its free ends, and wherein a first end of the member includes a rubber gasket allowing for injection of high penetration two-part hybrid urethane to form a tough instant polymer concrete

Further aspects of the invention which should be considered in all its novel aspects will become apparent from the following description which is given by way of example only. Brief Description of the Drawings

The invention will now be described by way of example only and with reference to the drawings in which:

Figure 1 is a photograph of an example of a rubber gasket fitted to a tubular member usable in accordance with the invention fitted to a static mixer; Figure 2 is a photograph of the static mixer and tubular member shown in Figure 1 before the rubber gasket is fitted;

Figure 3 is a photograph showing from the side part of a static mixer and showing from end on the inserts for the tubular member, rubber gasket and the tubular member;

Figure 4 is a section on an enlarged scale through a rubber gasket;

Figure 5 is an end view to scale of the rubber gasket shown in Figure 4; Figure 6 is a technical drawing of a rigid tubular member according to a first

embodiment of the invention; and Figure 7 is a rigid tubular member according to a second embodiment of the invention. It is arced in shape.

Detailed Description of the Invention An example of the invention will now be described with reference to a typical two pot or component resin cartridge being used to fill a crack in a vertical concrete wall. It is to be appreciated that the features of the invention can be used in a variety of situations to complete a repair or maintain the integrity of vertical or near vertical concrete structures as required. In the following description of the example in the drawings, similar integers will be referred to in the drawings using the same reference numbers.

The invention will now be described with reference to Figures 1 to 5 which shows a typical static mixer (1) adapted to be fitted to a two-component resin cartridge, such as urethane, which is not shown. The invention requires the use of a rigid tubular member (2) Figure 1 the length of which is generally slightly less than that of the static mixer (1). The rigid tubular member is preferably manufactured from steel or a similar rigid material. The tubular metal member (2) has at each end inserts (3 and 3') which are of a complementary shape to that of the external shape of the static mixer (2). The tubular member (2) has fitted to its free end (4) a rubber gasket (5), an example of which is shown in Figures 2 and 3. The rubber gasket (5) has a bore (6) which is dimensioned to engage with the end (7) of the static mixer (1).

The rubber gasket (5) may be manufactured by injection moulding and is shown with internal ribs (8) to provide a degree of rigidity. It is to be

appreciated that the strengthening ribs may be external if preferred.

Preferably the gasket (5) is manufactured from a synthetic plastic polymer such as polyvinyl chloride (PVC) or a similar material having the properties of PVC.

A skeleton gun and a resin cartridge (not shown) with a static mixer (1) fitted thereto and with a rigid tubular member (2) and rubber gasket (5) is used to inject resin under pressures typically up to 60 psi into a hole or crack. In practice a long crack in a concrete structure is partly covered by a fast setting cement with the crack left exposed at intervals.

The exposed sections of crack are small in size and are preferably of a size which can be covered by the face of the rubber gasket (5) so that when the crack is to be filled, the exposed section is covered, and the injected resin inserted. The injected resin is visible as it migrates in the crack in adjacent exposed sections along the length of the crack. The viscosity of the resin is such that where it is exposed it should be sealed by wax while it sets.

Figures 6 and 7 show technical drawings of the present invention. Figure 7 shows a variation of the present invention in that the rigid tubular member (2) is in the shape of an arc. The rigid member is also designed to fit over a tubular static mixer (9) and it includes a rubber gasket (10) as per the first embodiment. The rigid tubular member according to the second embodiment has an arc of about 68° and a length of abut 120mm. However, this can be varied according to the size and shape of the static mixer. The overall length of the tubular insert in both the straight and arced versions is about 153mm.

The arced rigid tubular member is designed for spaces where the straight stiffener cannot fit. This is either for tight corners and/or where there is an obstruction such as for example, warehouse shelving.

The applicant system, method and application design were produced

specifically for use as a one-day crack repair system for wall repair with

Roadware Ten Minute Mender™ which is a high penetration two-part hybrid urethane to form a tough instant polymer concrete. This thinner than water formula is designed for Microdoweling™ deep into the host concrete, creating extremely high bond strengths, reinforcement of the repair area as well as permanent repairs. It produces concrete repairs that absorb the shock and transfers the load without cracking or dis-bonding. It is chemically resistant and can be applied at a wide range of temperatures. It is to be appreciated however that the present invention can be used with other products such as LV epoxy, etc. with other sealing rubbers and/ or the rubber gasket even though this can require a minimum of two days to cure.

To prepare the Roadware 10-Minute Concrete Mender™ cartridge for injection, the items required are:

• Gebbie Tech Steel Stiffener - straight / Gebbie Tech Steel Stiffener - 60-100-degree angle · Gebbie Tech Rubber Gaskets • Roadware Application Gun

• Rubber gloves,

• Safety glasses

• Thread tape · A nail for use with the cartridge

• A cup for purging

• A clean rag Mode of operation

1. To prepare the cartridge, remove cartridge nut, cartridge and static mixer from the bag.

2. Take off the plastic cap which will contain the flow controller. Then remove the D-Plugs on the cartridge.

3. Some cartridges may have congealment. Use the nail to remove any congealment that has gathered at the surface of the cartridge. 4. Rip off approximately 2 inches of thread tape and place this across the join of the two cartridges, to prevent leakages when it is under pressure.

5. Then place the flow controller on the cartridge.

6. Place the static mixer on top of the flow controller, and then the locking nut to hold this together. 7. Now, pick up the Gebbie Tech Steel Stiffener. Place the flat end over the static mixer, so that the concave end is to the top.

8. Place the Gebbie Tech Rubber Gasket on top of the static mixer and stiffener.

9. Place the cartridge into the dispensing gun. Ensure you keep the gun on a downward angle so that you do not get any air locks mixing back in to the cartridge.

10. Purge out a minimal amount so that you have the products mixing together properly.

Injection/application: 1. injections should always be completed from the lowest point, working upwards. You do this to ensure penetration to the back of the wall. If this is not completed, you may have voids, which would compromise the repair of the wall.

2. It is preferable that you complete the wall repairs with two people. One person injects, the other person seals the crack, and wipes up the excess resin.

3. When injecting close to the floor hold the gun with the handle pointing upwards to enable the lowest injection point to be injected. Ensure the gun is still pointed slightly downhill to stop any back flow.

4. Use minimal pressure and inject until the urethane resin comes out of the crack above.

5. Then seal the injection point after the gun is removed with candle wax. 6. When you are clear of the floor you can rotate the injection gun so the handle points downwards.

7. It is important to always hold the gun with the nozzle pointing slightly down wards to ensure no back flow and early curing of the cartridge. 8. Inject each injection point, and wax seal until you have completed all injection points.

9. It is important to purge the gun on a regular basis. This is because the resin is quick setting, and will be setting within the static mixer head. Purging makes sure, that fresh resin is retained in the static mixer head. 10. Wait for the Roadware 10-Minute Concrete Mender™ to cure. The cure time is dependent on temperature. As a general guide wait approximately 30 minutes for a solid cure at 65 degrees Fahrenheit.

Repairing tight spaces - 80-degree bend steel stiffener:

Use the 80 Degree Steel Stiffener to repair the wall where there is an obstruction and the length of the standard set-up cannot fit.

This can happen where machines are fixed in place or warehouse pallet racking etc.

The process:

1. Place the static mixer in boiling water for 5 minutes. 2. Remove the static mixer from water and place the locking nut over the static mixer as shown.

3. Place the static mixer with a locking nut on over the plastic spacer. 4. Place the 80-degree bend steel stiffener over the static mixer nozzle.

5. Make sure the flat end of the steel stiffener is towards the locking nut.

6. Feed the 80-degree angled steel stiffener over the static mixer as quickly as possible. 7. Remove the plastic spacer and continue assembling the cartridge.

Where in the above description particular mechanical integers are described it is envisaged that their mechanical equivalents can be substituted as if they were described herein.

This invention provides a system for repairing and maintaining holes, cracks or damage in concrete walls.

A particular example of the invention has been described and it is envisaged that improvements and modifications can take place without departing from the scope thereof.

Industrial Applicability

The invention provides a system for repairing cracks and the like in concrete walls. The invention describes a rigid tubular member that is adapted to fit over a static mixer of a cartridge. The rigid member prevents that static mixer from being or being distorted when resin is being injected under pressure into the crack to be repaired. The rigid tubular member may be straight or curved in shape. It includes a rubber gasket adapted for insertion on the end of a static mixer of a resin cartridge. The gasket rests firmly on the rigid tubular member on the mixer so pressure is maintained to provide a seal between the static mixer and concrete without distorting or bending the mixer as it is used.