AU687631B2 - Method of construction of modular rainwater tanks - Google Patents

Description

Regulation 3.2

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

Name of Applicant: Stark's Sheet Metal Pty Ltd Actual Inventors: Peter James Stark and Bruce Kenneth Stark Address for Service: MADDERNS, 1st Floor, 64 Hindmarsh Square, Adelaide, South Australia, Australia Invention title: Method Of Construction Of Modular Rainwater Tanks Details of Associated Provisional Application No: PM 8990 dated October 1994.

The following statement is a full description of this invention, including the best method of performing it known to us.

This invention relates to a method and means of constructing light metal structures and in particular to the construction of rainwater tanks.

BACKGROUND

The invention relates to a method and means of joining sheet metal panels and is therefore applicable to a great many products manufactured using this material. For illustration purposes the field of rainwater tanks is used herein.

Quality of water used to supply household needs is increasingly becoming important to householders and in an effort to reduce their reliance on mains reticulated water, •.T6 increasing numbers of householders are installing rainwater ~tanks for the collection of rainwater from the roofs of their own houses.

oooo Rainwater tanks are available in a variety of capacities and shapes. Rainwater tanks having capacities in the vicinity of 400 to 1400 litres are popular and typically have a shape Ssuitable for installation against the walls of houses so as to minimise the use of scarce yard area.

This type of tank is commonly referred to as a modular rainwater tank since its substantially rectangular form may be easily abutted against the house wall and against similar tanks in a modular fashion to increase the total amount of water held for household purposes.

Modular water tanks are typically constructed from sheet metal which is bent into shape and welded or seamed at the joints to form a watertight container. The simplest construction configuration comprises a single rectangular base panel and a single sheet bent to form three corners and joined at a fourth corner to form the upstanding side wall of the tank. The base is formed with a flange which abuts the wall and a watertight seal is formed by folding and/or soldering the base to the wall. The container is then capped with a further single rectangular top panel which is also sealed to the unitary wall of the tank. Various inlets and outlets as required are then fitted or formed.

The tank is transported in its finished form needing only a tank stand and connection for use to commence.

Typically, one or two identical panels of sheet metal are used to form the upright wall of the tank.

One method of construction comprises the use of two identically [-shaped wall portions which are placed open end to open end to form a substantially rectangular side wall shape. The abutting ends of the wall portions are joined using known seaming joints which are also typically silicone sealed on the inside to increase their water retaining properties. The details of the various seaming joints and means will be described later in the specification.

In a further method of constructing a rectangular upright wall of a modular rainwater tank two L-shaped panels of sheet metal are placed together and joined at two corners of the substantially rectangular tank wall thereby formed. The joining method is typically a well known seam (eg Pittsburgn fold) and also typically the seam is sealed with silicone on the inside. Details of this seaming method will also be described later in the specification.

These two construction methods, using either one or two sheet metal panels are awkward, labour intensive and costly to manufacture.

The tanks are of such a size that it requires at least one or two skilled persons to bend the relatively large panels and to place them into position for seaming the joints to join them. The panels are awkward to carry and position because the sheet metal is not self-supporting and sharp edges of the metal make handling the panels dangerous. PreEerably two skilled people are used to safely manipulate the formed panels during the making process and final silicone sealing requires further labour and materials.

A variety of known seams, as depicted in Figs 1-5, can be used to form joins between abutting ends or side of lightgauge sheet metal parts. Some are not suitable for use when water and other fluids need to be contained but the invention is not limited to such applications so a review of some of the more common seams is warranted.

Figs 1 and 2 depict a lock seam typically used on longitudinal seams which do not have to be tight and can be located either outside (Fig 1) or inside (Fig 2).

The compound seam Fig 3, sometimes referred to as the Gordon or box seam is stronger and tighter than a lock seam.

Both seam types can be formed and closed with hand operated and/or powered seaming presses.

Seams best suited to joining the bottom of a container to its upright walls are referred to as bottom seams. Fig 4 depicts a double seam suitable for a flat bottomed container. This type of seam is used only on one end of the container since m o e: 25 access to its interior is required during the forming process.

e e Fig 5 depicts a double seam suitable for a recessed flat bottomed container. Double seaming with a recessed bottom panel can be used at both ends of a container.

Some of the seams formed require labour intensive tooling processes to finish them off. These additional processes are noisy and potentially hazardous to workers. These processes are furthermore, time consuming and labour intensive since mechanisation of some of those processes is not yet possible.

A further problem with prior methods of constructing modular rainwater tanks is the need to construct the tank fully before transportation. The expense of transport becomes a consideration since the majority of the cost of transportation is incurred in moving the volume and not the weight of the modular rainwater tank.

It is anticipated that the invention described herein will reduce or eliminate some of the problems of the prior methods of constructing modular rainwater tanks and of course other structures constructed of sheet metal material as well as provide an opportunity to reduce transportation costs when the structure needs to be moved prior to construction..

BRIEF DESCRIPTION OF THE INVENTION In a broad aspect of the invention a joint between metal panels for forming the corner of a structure comprising a first metal panel having at least one first joint i member along an edge comprising a flange extending away from S'said first panel, a second metal panel having at least one second joint member along an edge comprising a ledge extending away from said second panel, and a substantially U-shaped channel comprising two sides and a web where the first side depends from said ledge, the plane of the second side is parallel S with the plane of the first side and the end of said second side is spaced from said ledge thereby forming a slot, wherein said joint between said first and second panels S is formed by placing said flange between said sides of said U-shaped channel so that said first panel extends between and away from said slot and pressing either side of said U-shaped channel to cause said slot to close so that the end of said second side of the U-shaped channel is forced against said first panel which is forced against said ledge.

An embodiment of the invention will now be described however it will be recognised that the embodiment depicts but one arrangement the elements of the invention in such a manner as to perform the functions required of the invention.

BRIEF DESCRIPTION OF THE FIGURES To better illustrate the invention the follow description provides a preferred way of using the corner joint of the invention to provide the abovementioned features.

Fig 1 depicts a prior art longitudinal outside lock seam; Fig 2 depicts a prior art longitudinal inside lock seam; Fig 3 depicts a prior art compound longitudinal seam; Fig 4 depicts a prior art double seam for flat bottomed containers; Fig 5 depicts a prior art double seam for recessed bottom containers; Fig 6 depicts a prior art mid-wall seam; Fig 7 depicts a prior art single groove seam and tool to form the seam; Fig 8 depicts a perspective top view of a four walled S rainwater tank structure; S Fig 9 depicts a detailed view of one corner joint of the rainwater tank; and Fig 10 depicts a detailed view of a finished corner joint of a rainwater tank.

e DETAILED DESCRIPTION OF AN EMBODIMENT OF THE INVENTION Referring to Fig 6 thrre is depicted a prior art mid-wall S" seam 10. A tank constructed using this type of seam may S comprise either one or two sheets of light gauge metal joined intermediate either one or both end walls.

Sheets of light gauge metal are difficult to handle during manufacture as well as during the joining process. The manufacturing process requires that the facing ends of the end panels be bent, using in this example a S-bend rollforming machine. The identical S-bends are orientated in the manner shown in Fig 6 and joined by placing one S-bend into the other. The joined bends are then rolled together by a machine or alternatively hammered together to thus form an end wall portion of a tank.

-L L Ir _1 I Fig 7 depicts a further prior art single groove seam which is created by bending the edges of the panels in a simple bending machine. These overturned edges are laced together and the wall of the tank is formed into the rectangular form of the tank before finishing off the joint.

A special tool 12 is used to hammer the laced edges of the panels with the assistance of a shaped bar 14 resting against the inside surface of the wall.

The single or two panel construction is awkward to stack prior to construction as well as being an inefficient use of volume during transportation.

As tank sizes increase, the weight and awkwardness of the S panels also increase to the point that the manufacturing process may require more than two skilled workers.

All of the prior art methods described preferably use :20 silicone on the inside of the tank wall along the seam of the join to provide a primary barrier to water entering the folds of the seam, Common to all of the prior art methods of manufacture of a modular rainwater tank is the need to manually hammer and finish off the forming of the seams to provide a substantially watertight joint between a panel or panels.

This is necessary because to form the seam, access to both the inside and outside of the tank wall at the same time is required and tools to provide this type of access are not readily available.

Furthermore it is common to each of the prior methods of construction and panel arrangements that during manufacture and transportation of the panels the individual construction elements of the tank are awkward to handle and wasteful of transportation space.

Fig 8 depicts a perspective top plan view of the side walls of a modular rainwater tank constructed according to the invention having in this embodiment substantially planar side wall profiles.

However it is not unusual for one or more panels of modular rainwater tanks of certain sizes to be shaped to strengthen the panels so as to decrease the likelihood of distortion of the tank when filed with rainwater and to support the weight and flow of water through the tank.

The planar form shown in the figures is merely to simplify the schematic of this embodiment.

The side wall of the preferred embodiment of a rainwater tank constructed according to the invention comprises two identical end panels 22 and 24 and two identical side panels 26 and 28.

*e The immediate advantage of constructing the modular rainwater tank from four side wall panels is that, should there be a need for intermediate transportation of the modular rainwater tank before construction it can be done very economically S since the panels are substantially flat and even if they are corrugated or moulded in some other profile, they will stack substantially flat adjacent one another.

Furthermore, the upright wall of the tank is comprised of only two identical parts which simplifies the manufacturing process by requiring only two types of rollforming or bending machines to form this portion of the tank.

Yet furthermore, only the panel which is required to be fitted with a socket, tap or inlet and outlet apertures needs to be handled during that manufacturing stage. This means that the person inserting these items into the panel need only manipulate a relatively simple shape of reasonable size and weight. Therefore, handling the panel is safer and quicker and consequently it is very economical to manufacture a tank with the desired sockets and apertures in place rather than after the walls are joined as is typical.

An unfinished corner seam of the tank is shown schematically in Fig 9 and a finished corner seam 30 is shown in more detail in Fig Fig 9 depicts an end panel 24 having along one of its edges a first joint member comprising a flange 32 which is bent to a right angle with respect to the plane of panel 24.

Side panel 28 has along one of its edges a second joint member comprising in part a ledge 34. This ledge extends outwards, typically at a right angle to the panel and away o from the plane of the side panel 28 a distance at least the thickness of the first panel 24.

The second joint member of side panel 28 further comprises an extension of the ledge 34 in the form of a shaped channel 36 having two sides 38 and 40 and a web 42. At the free end 44 of the shaped portion 36 a gap is left between it and the ledge 34 of at least the thickness of the end panel 24.

Fig 9 also depicts the flange 32 of the end panel 24 located inside the second joint member (34, 36) of the side panel 28 so as to form a structure to join the panels 24 and 28. The joint so formed can be finished (by a seaming operation) from outside the tank wall being formed and does not require any internal access of tools or workers.

Preferably although not necessarily all of the panels 22, 24, 26 and 28 are located in a joined manner to form the side wall of the modular rainwater tank before final seaming operations are performed.

The final operation of seaming the joints is preferably performed by rolling the sides of the shaped channel 36.

A commonly available hand-held rolling machine is preferably used in this process. A rolling machine can be easily located 9 over the externally accessible joins of the panels and drawn downwards or upwards along the full length of the join to form the finished seam as is depicted in Fig Fig 10 depicts the result of the application of the rolling machine which forces either side of the shaped part of the side wall joint member so as to cause the slot to close when the free end 44 of the shaped channel 36 forces the end panel 24 against the ledge portion 34 of the end panel 28. This rolling process also captures the flange 32 of end wall 24 within the shaped channel of the second joint member and thereby fixes end wall panel 24 relative to side wall panel 28.

r ~Firm abutment of end wall panel 24 against ledge portion 34 of side wall panel 28 provides a watertight seal which typically does not require a primary silicone bead seal internal of the tank. This form of corner joint can thereby reduce cost and labour in the manufacture of a rainwater tank.

The shape of the second joint member can be formed by a standard rollforming machine therefore manufacture of side wall panels having this configuration is a safe and simple procedure.

It will be appreciated that the application of an S-bend and S right angle flange joint member respectively to side and end panels is only a preferred embodiment. The joint members described could be formed on the end wall panels and the result would be the opposite orientation of the joint at the corners of the tank. Furthermore it will be apparent that this form of joint need not be at right angles or in the plane of the wall panels and there may be structures which advantageously will have the orientation of the joint and angles of wall panels other than that depicted in the preferred embodiment.

It will be apparent that the invention resides in the use of a particular combination of joint members further the application of those joint members to a minimum number of similar panels makes the invention suitable for the construction or partial construction of structures which are easy to transport and construct particularly modular rainwater tanks.

*o*0 0o .oo e o o• o• oe o e i eo• eeo o °s° 6 I cl_ l

Claims (9)

1. A joint between metal panels for forming the corner of a structure comprising a first metal panel having at least one first joint member along an edge comprising a flange extending away from said first panel, a second metal panel having at least one second joint member along an edge comprising a ledge extending away from said second panel, and a substantially U-shaped channel comprising two sides and a web where the first side depends from said ledge, the plane of the second side is parallel with the plane of the first side and the end of said second side is spaced from said ledge thereby forming a slot, wherein said joint between said first and second panels S is formed by placing said flange between said sides of said S U-shaped channel so that said first panel extends between and S away from said slot and pressing either side of said U-shaped channel to cause said slot to close so that the end of said second side of the U-shaped channel is forced against said first panel which is forced against said ledge.

2. A joint according to claim 1 wherein said flange is at a right angle to the plane of said first metal panel and said ledge is at right angle to the plane of said second metal panel. :22

3. A water tank constructed using sheet metal panels, said tank comprising two side wall panels each having a first joint member along at least two opposing edges, each joint member comprising a flange extending away from said panel, a further two side wall panels each having a second joint member along at least two opposing edges, each second joint member comprising a ledge extending away from said further side wall panel, and a substantially U-shaped channel comprising two sides and a web where the first side depends from said ledge, the plane of the second side is parallel with the plane of the first side and the end of said second side is spaced from said ledge thereby forming a slot, wherein an upright wall of said tank is formed by placing the flange of first joint members of each side wall panel between sides of said U-shaped channel of said second joint members of each further side wall panel and pressing either side of said U-shaped channel to cause said slot to close so that the end of said second side of the U-shaped channel is forced against said first panel which is forced against said ledge to form a substantially watertight joint at each corner of said tank thereby formed, and a base panel water sealingly attached to an open end of said upright wall to form a water tank.

4. A water tank according to claim 3 wherein said flange is at a right angle to the plane of said first side wall panel and said ledge is at a right angle to the plane of said further side wall panel.

5. A water tank according to claim 3 wherein said side wall panels are substantially similar in profile and said further S. side wall panels are substantially similar in profile.

6. A water tank according to any of claims 3 to 5 wherein said remaining open end of said upright wall is sealed with a panel to form a fully enclosed water tank.

7. A water tank according to any of claims 3 to 6 further comprising the forming of inlet and outlet apertures to allow the inlet and outlet of water to and from said water tank.

8. A method of constructing a water tank comprising the steps of: forming two identical side wall panels which are substantially flat each having a first joint member along at least two opposing edges, each joint member comprising a flange extending away from said panel, I forming two identical further side wall panels which are substantially flat each having a second joint member along at least two opposing edges, each second joint member comprising a ledge extending away from said further side wall panel, and a substantially U-shaped channel comprising two sides and a web where the first side depends from said ledge, the plane of the second side is parallel with the plane of the first side and the end of said second side is spaced from said ledge thereby forming a slot, locating the first joint members of said two side wall panels in said second joint members of said two further side wall panels by placing the flange of first joint members of each side wall panel between sides of .0 .5 said U-shaped channel of said second joint members of each further side wall panel, pressing either side of said U-shaped channel to cause said slot to close so that the end of said second *side of the U-shaped channel is forced against said first panel which is forced against said ledge to form substantially watertight longitudinal joints external of said four walled tank thereby formed, forming and fixing in watertight manner a base panel to an open end of said four walled tank to form a water tank. S

9. A method of constructing a water tank according to claim 8 wherein said flange formed in step is at right angles to the plane of a respective said first side wall panel and said ledge formed in step is at a right angle to the plane of a respective said further side wall panel. A method of constructing a water tank according to claim 8 further comprising the step: forming and fixing a top panel to said open end of said four walled tank to fully enclose said water tank, and forming inlet and outlet apertures to allow the inlet and outlet of water to and from said water tank. Dated this 23rd day of October 1995. STARK'S SHEET METAL PTY LTD By its Patent Attorneys MADDERNS aete o a 4* 4 4 4o a ft c B 6 0 ABSTRACT The invention relates to a method and means of joining sheet metal panels and is therefore applicable to a great many products manufactured using this material. For illustration purposes the field of rainwater tanks is used herein. In particular a joint between metal panels (28, 24) for forming the corner of a structure comprises a first metal panel (24) having at least one first joint member along an edge comprising a flange (32) extending away from said first panel, a second metal panel (28) having at least one second joint member along an edge comprising a ledge (34) extending away from said second panel, and a substantially U-shaped channel (36) comprising two sides (38, 40) and a web (42) where the first side depends from said ledge, the plane of the second side is parallel with the plane of the first side and the end of said second side is spaced from said ledge thereby forming a slot wherein said joint between said first and second panels is formed by placing said flange between said sides of said U-shaped channel so that said first panel extends between and away from said slot and pressing either side of said U-shaped channel to cause said slot to close so that the end of said second side of the U- shaped channel is forced against said first panel which is forced against said ledge. In a further particular arrangement a water tank is constructed using sheet metal panels (22, 24, 26 and 28), where the tank comprises two side wall panels (26, 28) each having a first joint member along at least two opposing edges, each joint member comprising a flange (32) extending away from said panel, a further two side wall panels (22, 24) each having a second joint member along at least two opposing edges, each second joint member comprising a ledge (34) extending away from said further side wall panel, and a substantially U-shaped channel (36) comprising two sides (38, and a web (42) where the first side depends from said ledge, the plane of the second side is parallel with the plane of the first side and the end of said second side is spaced from said'ledge thereby forming a slot wherein an upright wall of said tank is formed by placing the flange of first joint members of each side wall panel between sides of said U-shaped channel of said second joint members of each further side wall panel and pressing either side of said U- shaped channel to cause said slot to close so that the end of said second side of the U-shaped channel is forced against said first panel which is forced against said ledge to form a substantially watertight joint at each corner of said tank thereby formed, and a base panel water sealingly attached to an open end of said upright wall to form a water tank. I II ~L d