AU753814B2 - A structural member - Google Patents

Description

1

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A PETTY PATENT Name of Applicant: Actual Inventor: Address for Service: Invention Title: MILLER'S TYRE SERVICE PTY. LIMITED C.N. 000 857 705) William Hopton MILLER CULLEN CO., Patent Trade Mark Attorneys, 240 Queen Street, Brisbane, Qld. 4000, Australia.

A STRUCTURAL MEMBER 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 structural member that can be used as guide posts for roads, fencing for stock yards, railway sleepers and the like. The invention will be described with reference to guide posts for roads.

However, the invention is not limited to guide posts and may be used for other purposes.

Most guide posts used to mark the boundaries of roads are made from wood. The guide posts are very rigid and snap at their base when struck by a moving motor vehicle. Considerable damage is caused to both and the post and the motor vehicle due to the posts lack of flexibility.

To replace a post that has been broken by a moving motor vehicle, the cement foundation holding the post must first be removed. The post is then placed in a hole, aligned and a new cement foundation poured.

This is a very time consuming and expensive process.

In an effort to reduce both of the above disadvantages rubber 15 posts made from recycled tyres have been developed. One known rubber 'post is described in Australian patent 632737. This rubber post is constructed from three tyre treads that are bonded together. The advantage with a rubber post is that when struck by a moving vehicle the rubber post bends. Thus little or no damage is caused to the car or to the post.

20 However, the problem with current rubber posts is that once the post has been struck by a car the post does not return to a vertical position.

Further, if the post has been struck more than once the post often lies S"adjacent to the ground and does not provide a guide to motorists.

It is an object of this invention to overcome some of the above 25 disadvantages or provide the consumer with a useful or commercial choice.

The invention resides in a structural member having an outer layer bonded to an inner layer, the inner layer constructed from at least one discrete length of tyre and an outer layer constructed from melted rubber.

The structural member may be used as railway sleepers, rails and posts for fences especially for stock, guide posts for roads, boarders for sand pits, tiles for floors and the like.

The inner layer may be constructed from the tread, steel belt and inner lining of the tyre. The steel belt may provide re-enforcement to the structural member. The tread may be buffed to produce an inner layer of the required thickness. The buffing of the tread may also allow improved adhesion of the outer layer.

Preferably more than one discrete length of tyre is used to form the inner layer. The discrete lengths may be held together by adhesives or fasteners or the like. The discrete lengths are preferably obtained from used tyres.

The outer layer can be made from virgin rubber, recycled rubber or a mixture of the two. The recycled rubber used may be from recycled tyres. The recycled rubber may be treated to enable the rubber to be melted. A suitable treatment is that described in US Patent No. 4,481,335.

The treated recycle rubber may be in the form of crumbs before they are "melted.

15 In another form, the invention resides in a method of producing a structural member including the steps of locating at least one discrete "°"length of a tyre within a mould, placing rubber around the outside of the tyre, and applying heat and pressure to the rubber via the mould to melt the rubber to the tyre.

S' 20 The rubber and the discrete lengths of tyre used may be of the same nature as that described above.

S-An embodiment of the invention will be described with reference to the accompanying drawings in which SFigure 1 is a perspective view of a rubber guide post for a road according to an embodiment of the invention.

Figure 2 is a sectional side view of a rubber guide post according to Figure 1.

Figure 3 is a perspective view of an inner layer of a rubber guide post.

Figure 4 is a perspective view of a mould used to produce a rubber guide post as shown in Figures 1 and 2.

Figures 1 and 2 show a guide post 10 that comprises an outer 4 layer 11 and an inner layer 12.

The inner layer 12, shown in more detail in figure 3, is made up of three discrete lengths of used rubber tyre. Fasteners or adhesives are used to fix the discrete lengths of each of the rubber tyres to each other.

Each discrete length of rubber tyre includes part of the tread, steel belt and inner lining of the tyre. The steel belt provides reinforcement to the guide post 10. The tread can also be used to reinforce the guide post The tread of each of the discrete lengths is buffed using a buffing machine. This reduces the thickness of the discrete length of rubber tyre to that desired. Further, the buffing allows the outer layer 11 to more effectively adhere to the inner layer 12.

The outer layer 11 is made from rubber crumbs that are produced when re-treading a tyre. Grinding or buffing a rubber tyre also produces these rubber crumbs. The rubber crumbs are treated to allow the 15 rubber crumbs to be heated to form an effective melt. The rubber crumbs are treated according to the process described in US Patent No. 4,481,335. This S"allows the treated rubber crumbs to bond with cured rubber such as that found in tyres.

A mould 20 having a top 20A and bottom 20B is used to make 20 the guide post 10. To produce the guide post 10, rubber crumbs are placed in the bottom of the mould 20B shown in Figure 4. The discrete lengths of S" tyre are fastened together and placed within the bottom mould. More rubber crumbs are added until the rubber crumbs surround the discrete lengths. The top of the mould 20A is placed on the bottom of the mould and pressure is 25 applied. The mould 20 is heated to approximately 150 degrees Celsius to melt and subsequently bond the rubber to the tyres. A thermocouple check is conducted on the guide post 10 to determine if the guide post 10 is cured.

The normal curing timing for a guide post 10 is approximately 15 to minutes.

A recess for a reflector 30 and soil retention grooves 31 are formed within the guide post 10 using the mould 20. The guide post provides the advantage that when struck by a moving vehicle the guide post returns to its original position. This is due to the outer layer 11 being bonded to the inner layer 12.

The above process can be used to produce tiles, railway sleepers, fencing post and rails, barricades and the like. The process Sproduces structural members that have good shape memory properties.

It should be appreciated that various other changes and modifications may be made without departing from the spirit or scope of the invention.

gNas **ee m e oI

Claims (3)

1. A structural member having an outer layer bonded to an inner layer, the inner layer constructed from at least one discrete length of a tyre and an outer layer constructed from melted rubber.

2. The structural member of claim 1 wherein the discrete length of tyre comprises tread, steel belt and inner lining.

3. The structural member of claim 1 or claim 2 as substantially hereinbefore described with reference to the accompanying drawings. DATED this 17 th day of December 1997 MILLER'S TYRE SERVICE PTY. LIMITED 000 857 705) By their Patent Attorneys CULLEN CO. *e e