AU2004222777B2 - Wheel Tread - Google Patents

Description

-1- Regulation 3.2

AUSTRALIA

PATENTS ACT, 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

Name of Applicant: Actual Inventor: Address for service in Australia: Invention Title: JAKAAR INDUSTRIES LIMITED ALAN EDWARD HOLT A J PARK, Level 11, 60 Marcus Clarke Street, Canberra ACT 2601, Australia WHEEL TREAD 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 wheel, roller or tyre tread. The invention is directed particularly, but not solely, towards wheel treads for the rollers of boat trailers.

Conventional wheel treads for wheels or rollers of devices such as trailers, 0 lawnmowers, material conveyors and vehicles etc, may comprise a moulded tread pattern having transverse ribs, having uniform gaps or depressions therebetween, to facilitate traction and drainage.

These treads or transverse ribs/raided portions and gaps have the disadvantage of causing significant noise during movement of materials or objects over them, or when moving N an object having wheels, over a contracting surface such as the ground. The noise is produced S 10 by the moving object hitting or colliding with each consecutive rib. It is also difficult to Sinitiate motion of the object, as the object such as a boat, tends to rest and settle between the N ribs within the depression. Moving means that the object must be pushed over and against each rib. The weight of any object combined with the settling of the object between the ribs makes it extremely difficult to initiate motion to overcome existing inertia. It also makes for more effort in general to push or move an object over the wheels or an object having the wheels attached to it.

The action of the ribbing colliding and impacting the surface of an object can also cause work hardening of non-plastic objects such as aluminium boats. This has tended to reduce their acceptance in New Zealand whereby flat treads have been preferred. For nonplastic boats such as fibreglass boats, the ribbed treaded wheels are still commonly used.

It is the object of the present invention to provide an improved wheel, roller or tyre tread which will obviate or minimise the aforementioned problems in a simple yet effective manner or which will at least provide the public with a useful choice of wheel, roller or tyre tread.

In an aspect the present invention consists in a boat roller comprising: a roller body, a non pneumatic tyre like form in a resiliently deformable material moulded to define a tread on the roller body; wherein the tread is characterised in that: it is of a sequence of raised and depressed forms about the rolling perimeter, each raised form extending from one side to the other of the treaded area of the tyre like form, where notionally rolling on a flat surface parallel to the roller axis, the transition of primarily surface contact from one raised form of the tread to primarily surface contact from that raised form immediately following about the -3rolling perimeter, irrespective of rolling directions, has part of both raised forms making contact, and (ii) at least substantially the full side to side extent of each raised form, but 0 not necessarily simultaneously, will contact such a flat surface during such notional rolling, and

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each of proximate raised and depressed form transitions from one to the other by a substantially smooth curve from one side to the other.

Preferably each depressed form, when viewed towards the rotational axis, is of a N similar shape to the shape of the proximate raised forms.

N 10 Preferably the raised form(s) are at least substantially identical and the proximate raised forms mutually nest in part about the rolling perimeter despite an intervening depressed Ni, form.

Preferably proximate raised forms present, when viewed in silhouette normal to the axis rotational, substantially straight outline parallel to the roller.

Preferably the tread has been moulded.

Preferably each said smooth curve is S shaped, or C shaped.

Preferably said raised forms of the tread can be compressed so as to have part of adjacent raised forms making contact.

In another aspect the present invention consists in a boat support or boat trailer having at least one boat roller.

Throughout the description and claims of this specification the word "comprise" and variations of that word, such as "comprises" and "comprising", are not intended to exclude other additives, components, integers or steps.

As used herein the term "immediate" with respect to transition from one raised form of the tread to that raised form immediately following about the perimeter is sufficiently soon and/or involves regions of both under load so as to not produce noise and/or not substantially resist initiating motion.

As used herein the term "and/or" means "and" or or where the circumstances allows, both.

As used herein the term following a noun means as is appropriate the plural and/or singular forms of that noun.

Reference hereto the "side" of the tread refers to the extent of the tread laterally of the rolling perimeter to the extent to which there is any prospect that the tread can make contact with a said notional flat surface.

Preferred forms of the invention will now be described with reference to the accompanying drawings in which: Figure 1 is a perspective view of a first embodiment of the wheel or roller tread in use 0 on a typical wheel rim, Figure 2 is a side view of the wheel tread,

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Figure 3 is a left hand side view of the wheel tread, Figure 4 is a right hand side view of the wheel tread, -Figure 5 is a top view of the wheel tread, N( Figure 6 is a bottom view of the wheel tread, N 10 Figure 7 is a second embodiment of a wheel or roller tread in perspective, and Figure 8 is that second embodiment tread.

Many regular or irregular forms of tread are capable of satisfying the aims of the present invention which is to minimise noise when in use. In the following two embodiments a fully extensive or substantially fully extensive series of regular raised forms are provided which under compression in use (e.g as a boat roller or as a dolly wheel or the like) will have the effect of ensuring that part or parts of one raised region is on any supporting surface as the weight is being taken on (or is immediately about to be taken on) by a first part or first parts its following raised area. Therefore the terms "nested" or "nest", or variations of it, envisage raised forms sufficiently intermingling or adjacent so that there is or can be (with or without tread deformation) the smooth transition. See lines A-A (Figure 3) and B-B (Figure 8) which show without deformation some prospect of continuity of load bearing at transition.

As shown in various view of Figures 1 to 6 the wheel tread 1 is shown on a typical wheel rim 2. This wheel can be part of any vehicle such as a trailer, e.g. for boats or for carrying materials as in a trade trailer, or for lawnmowers, conveyors and other commercial/non commercial use or also a car/truck etc.

In use, the longitudinal direction in which the wheel will roll or the circumferential direction of the wheel tread or wheel, as being the longitudinal axis and the transverse axis being perpendicular to this axis and being coincident with the width of a tread and defining the length of the raised portions. Each wheel tread has at least one raised portion 3 extending from a base 4 forming depressions 5 therebetween. There can be a plurality of raised portions forming a plurality of depressions.

The outer contacting surface 6 is defined as that surface that contacts the object being moved over or as in other uses, this contacting surface can be the surface over which the wheel can be rolled over such as the ground/floor/planar surface etc. The outer surface can flat or shaped flat/planar or contoured to any shape desired. Further grooves, recesses or profiling can be added to further enhance traction drainage of sand/water and for aesthetics or advertising.

0 Side walls are shown as items 7 and 8 and can be any suitable angle with respect to the base and/or outer surface or can be contoured or curved. Each raised portion can be sized and

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dimensioned to suit individual requirements and uses as shown in Figures 3 and 6, each typical raised portion 9 is elongate in overall shape having a centre portion 10 and end walls 11 and 12.

N In use, for example, if a boat is winched over the wheel tread, the boat hull outer N 10 surface will contact any two adjacent raised portions 10 and 13 at selected points of contact Srather than the complete transverse line of contact which is typical in the conventional ribbed N wheel tread. A maximum of three points of contact between any raised portion and a contacting surface, are formed at. Alternatively there may just one point of contact on a raised portion. During one instance of contact, the hull surface lies between two raised portions 10 and 13 with a point of contact will lying at the centre of the length of depression between raised portions 10 and 13 and two outer points of contact at an adjacent raised portion 13 this being the three point contact point. In summary, during the motion of wheel tread, there are three types of contact points. Firstly, there are a maximum of three points of contact between the contacting surface and the wheel tread for two raised portions (first and second raised portions); secondly followed by two points of contact on one raised portion (spaced apart on the second raised portion) and thirdly followed by one point of contact on one raised portion (in the middle of the second raised portion).

In a second instance the contact when the contacting surface of the boat moves from the centre of the length of the depression between adjacent wheel treads, the point of contact can be over the middle of one raised portion having the outer portion of the boat contacting surface lying in mid air over the depression between the adjacent raised portion in the forward direction. Therefore the contact points will shift between the two extremes just mentioned thereby enabling a smooth motion to be produced, such that no noise or clicking or impact is produced during the rotation or movement over the wheel tread and that there is no significant resting inertia to be overcome when the boar surface lies between two raised portions.

Significantly during motion of the wheel or motion over the wheel, the contacting surface of the object or ground will always be supported by at least a portion of at least one raised portion.

In other variations of the shape of the raised portion, the shape can be "banana" shaped, S shaped, or V shaped or any combination thereof the both maintains contact with a portion of a raised portion at all times of the motion or movement. Another example for a 0 raised portion is spiral shaped or randomly "curling/curving" raised portion running continuously circumferentially around the base of the wheel tread thereby only having one

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raised portion. Conceivably any of the shapes may be continuously extended around the base.

Limitations are normally imposed by economics and the moulding process whereby removal r of the moulds will require a specific design to enable a set pattern to be economically (produced. The tread can be manufactured from any suitable materials such as plastics or rubber or any combinations therein. The side walls of each raised portion can be angled with respect to the outer contacting surface or it may be curved or whatever facilitates its use and/or manufacturing techniques.

Figures 7 and 8 show a variant to the form of wheel shown in Figures 1 through 6.

In this form of the invention raised regions 16 are identical throughout the rolling perimeter but are positioned so as to interpose depressions 17 between each which has a similar form to that of each raised region even if not to the same area. There is sufficient depression area 17 such that deformation of the raised regions 16 will mean that on a line such as, for example, B-B transverse to the rolling axis there is a prospect that first a raised region 16A and then its subsequent raised region 16B will simultaneously have regions thereof bearing weight. Likewise 16B to 16BB.

If need be the closeness together of the raised regions 16 about the rolling perimeter of the wheel can be closer i.e more nested than as shown.

As stated previously preferably the tyre like form shown as a moulding as Figures 7 and 8 is preferably heat moulded about, for example, a wheel or roller hub, rim or the like. A suitable more rigid and less compressible material is used for such a hub or rim (e.g a polypropylene) with which for example a tyre form as shown in Figures 7 and 8 can be moulded (e.g of TPR rubber).

The wheel tread has the following advantages: 1. Excellent load carrying capabilities.

2. Reduced noise during use.

3. Adaptable to most trailers.

4. Simple to install/replacement.

-7- Durable plastics.

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6. Little effort needed to push the wheel.

7. Free rolling wheel.

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8. Continuous support/contact of boat hull by the tread.

Claims (9)

1. A boat roller comprising: 0 a roller body, a non pneumatic tyre like form in a resiliently deformable material moulded to define a tread on the roller body; wherein the tread is characterised in that: it is of a sequence of raised and depressed forms about the rolling perimeter, N each raised form extending from one side to the other of the treaded area of the tyre like form, S 10 where notionally rolling on a flat surface parallel to the roller axis, the transition of primarily surface contact from one raised form of the N tread to primarily surface contact from that raised form immediately following about the rolling perimeter, irrespective of rolling directions, has part of both raised forms making contact, and (ii) at least substantially the full side to side extent of each raised form, but not necessarily simultaneously, will contact such a flat surface during such notional rolling, and each of proximate raised and depressed form transitions from one to the other by a substantially smooth curve from one side to the other.

2. A boat roller of claim 1 wherein each depressed form, when viewed towards the rotational axis, is of a similar shape to the shape of the proximate raised forms.

3. A boat roller of claim 1 or 2 wherein the raised form(s) are at least substantially identical and the proximate raised forms mutually nest in part about the rolling perimeter despite an intervening depressed form.

4. A boat roller of any one of the preceding claims wherein proximate raised forms present, when viewed in silhouette normal to the axis rotational, substantially straight outline parallel to the roller.

A boat roller of any one of the preceding claims wherein the tread has been moulded.

6. A boat roller as claimed in any one of the preceding claims wherein each said smooth curve is S shaped, or C shaped.

7. A boat roller of any one of the preceding claims wherein said raised forms of the tread can be compressed so as to have part of adjacent raised forms making contact.

8. A boat roller as claimed in any one of the preceding claims substantially as hereinbefore described with reference to any one, some or all of the accompanying drawings. -9-

9. A boat support or boat trailer having at least one boat roller as claimed in claim any one of the preceding claims.