BACKGROUND OF THE INVENTION There are various situations in which the use of a device which indicates slope or gradient of machinery is required. For example, when building new roads, grading equipment typically includes some form of slope indication device in order to ensure that a pre-determined slope in the road surface is achieved. Another example is the digging of holes whereby the slope of the digging machinery is to be monitored to ensure that the hole is drilled at a required angle. In general, most forms of construction machinery such as bull-dozers, dump-trucks, bobcats, paving machines, graders and drill-rigs all require some form of gradient indication to ensure adequate operation.

Although the present invention refers specifically to mining operations and the use of bull-dozers therein, it is to be understood that it is not to be limited to this particular operation and may certainly be used in other related situations such as those mentioned above.

Gradient indicator devices have existed for many years and in various forms. The earlier forms of gradient or slope indicators were relatively simple devices incorporating the use of spirit levels. More advanced devices utilising technologies such as laser indicators and GPS (Global Positioning System) have evolved in more recent times. In the case of GPS, information about the machinery such as longitudinal and transverse slope is measured and transmitted via satellite. Although found to be effective, these devices are very expensive and difficult to operate. GPS systems are also not able to be used in underground operations.

Machine operators in the mining industry have found that in most situations, there is no need for a high-tech slope indication device, but rather a device that will simply indicate to the driver in real time the longitudinal and transverse gradients of the machine being driven. In most mining operations in which ground slopes are to be created, it is not necessary for absolutely precise slope readings to be indicated to the driver, such as that which would result from a GPS reading for example, but rather an approximate representation of the gradient being created. In using indicators such as these which are cumbersome to operate, the time to complete a task increases resulting in more fuel usage and hence more expense, and there is more wear and tear on machinery parts caused by mistakes made by operators.

An additional feature that is often sought after in a gradient indicator device is a more clear indication relating to standard batter angles that are commonly used in the industry, for example, batter

angles of 1: 10 for ramps, 1: 6 for rehab batters, and 1: 3 for fire batters. Such indications ensure that an operator can very quickly obtain an indication of the angle of the machinery without having to decipher digital readings associated with alternative indication means.

As mentioned previously, the design and configuration of existing gradient indication devices are often quite complex and as a result are not easily manufactured and assembled, particularly those involving the use of spirit-level indicators. It is therefore desirable for a gradient indicator device to be quickly and easily manufactured and assembled for use without the need for complex and therefore expensive manufacturing methods.

Mounting existing devices within machinery also poses a problem to operators. It is often required for bull-dozers and other machinery to be taken off-site to have such devices mounted therein.

This is because they must be precisely aligned within the machine, this especially being the case when using more complex devices. Insofar as the applicant is aware, there are no devices that include their own alignment means so that the device may be simply mounted within the machinery on-site.

It is therefore an object of the present invention to overcome at least some of the aforementioned problems or to provide the public with a useful alternative.

The present invention therefore relates to a gradient indicator device used to indicate to a driver of a bull-dozer or like machinery the longitudinal and/or transverse gradients of the machinery relative to a flat, horizontal surface. The device is adapted to be mounted in a longitudinal configuration for indicating slope relative to a longitudinal axis, or when the slope relative to a transverse axis is to be measured, the device is mounted in a transverse configuration.

SUMMARY OF THE INVENTION Therefore in one form of the invention there is proposed a gradient indicator device including: a longitudinal body; at least one longitudinal chamber associated with said longitudinal body wherein at least a portion of said chamber can be viewed from outside the body; visual indicia located in said chamber said indicia being of a cross-sectional size less than that of the chamber cross-section to allow for movement of said indicia through said chamber; and an indicating means for indicating the longitudinal gradient of the device, said indication corresponding with the position of said visual indicia in said chamber.

Preferably said longitudinal body includes an internal cavity which houses said longitudinal chamber in a convex configuration.

In preference said longitudinal chamber is a tubular chamber of circular cross-section said chamber being transparent so that said visual indicia is viewable from outside the chamber.

Preferably said fluid is of a predetermined viscosity to allow for said visual indicia to move through said fluid smoothly and at a predetermined speed.

Advantageously said fluid is oil and said visual indicia is a ball bearing.

Preferably said indication means is in the form of visual increments located on a surface of said device, said visual increments being spaced apart along and adjacent said longitudinal chamber.

Preferably each of said visual increments corresponds with a particular slope such that when said device is tilted in the longitudinal direction, the visual indicia will move and become aligned with a visual increment corresponding with the slope of the device.

In preference said device further includes a lighting means for illuminating said chamber and/or indication means.

Preferably said lighting means is a lamp mounted to an external surface of said device, said lamp adapted to externally illuminate said chamber and/or indication means.

Advantageously said lighting means is at least one Light-Emitting Diode (LED) lamp housed within said body, said lamp adapted to internally illuminate said chamber and/or indication means.

Preferably said body is adapted to house two LED lamps and a switch for activating said lamps.

In preference said indication means includes a plurality of increments disposed along a surface of said device and adjacent said chamber.

In preference said device is adapted to be mounted within a vehicle when said vehicle is located on a horizontal reference surface.

Preferably said device includes a second longitudinal chamber associated with said longitudinal body, said longitudinal chamber including visual indicia for indicating that said device is mounted level with respect to said horizontal reference surface.

Advantageously said second longitudinal chamber is a spirit level device and said visual indicia is an air bubble.

Preferably two of said devices are adapted to be used within a vehicle, a first device appropriately mounted within said vehicle for indicating the longitudinal slope of the vehicle, and a second device mounted perpendicularly to said first device for indicating the transverse slope of the vehicle.

Advantageously said tube includes a sensing means so that when said slope reaches a predetermined limit, an alarm means is activated.

In a further form of the invention there is proposed a gradient gauge for use in a vehicle used to create a surface of predetermined grade, said gradient gauge including : a longitudinal housing; a convex tube enclosing a visual indicia adapted to move through said tube when said gauge is tilted either forwards or backwards in the longitudinal direction; an indicator face adapted to be mounted to said housing, said indicator face including an aperture whereby at least part of said convex tube is viewable therethrough, said indicator face including visual increments defining a feature of slope such that when said gauge is tilted, the visual indicia moves and becomes aligned with an increment corresponding with said tilt.

Advantageously said feature of slope is a batter angle ratio.

Advantageously said feature of slope is the angle of tilt measured in degrees.

Preferably said gauge includes a horizontal spirit level for the purpose of mounting said gauge within said vehicle level with a reference horizontal surface.

In a still further form of the invention there is proposed a gradient indicator device including a first level indication means for ensuring that said device is attached to an interior surface of a vehicle substantially horizontally, and a second level indication means for indicting to the operator variations in slope of said vehicle.

Preferably when said gradient indicator device is attached to a transverse surface of said vehicle said second level indication means indicates the longitudinal slope, and when said gradient indicator device is attached to a longitudinal surface of said vehicle said second level indication means indicates the transverse slope.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several implementations of the invention and, together with the description, serve to explain the advantages and principles of the invention. In the drawings,

Figure 1 illustrates a side view of a bull-dozer travelling along a surface having a transverse batter angle of 1 : 6 as indicated by a gradient slope indicator in accordance with a first embodiment of the present invention, as well as a rear view of a bull-dozer travelling along a surface having a longitudinal batter angle ; Figure 2 illustrates a perspective view of a gradient indicator device in accordance with a second embodiment of the present invention whereby the device includes an externally mounted lamp ; Figure 3 illustrates a front view of a gradient indicator device according to a third embodiment of the present invention whereby the device includes internally mounted LED's and a horizontal spirit level ; Figure 4 illustrates a front view of the gradient indicator device of Figure 3 at a batter angle of 1: 10; Figure 5 illustrates an exploded view of the of the gradient indicator device of Figures 3-4; and Figure 6 illustrates a perspective view of a gradient indicator device in accordance with a fourth embodiment of the present invention; Figure 7 illustrates a front view of the gradient indicator device of Figure 6; Figure 8 illustrates a front view of the gradient indicator device of Figure with the front indicator face removed; Figure 9 illustrates an exploded view of the gradient indicator device of Figures 6-8; and Figure 10 illustrates a perspective view of two gradient indicator devices according to any one of the embodiments of the invention mounted longitudinally and transversely within a bull- dozer carriage.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The following detailed description of the invention refers to the accompanying drawings.

Although the description includes exemplary embodiments, other embodiments are possible, and changes may be made to the embodiments described without departing from the spirit and scope of the invention.

Wherever possible, the same reference numbers will be used throughout the drawings and the following description to refer to the same and like parts.

It is to be understood that any reference to the term'batter angle'is an indication of the ratio between the two adjacent edges of an angled surface. It is to be also understood that when referring to 'longitudinal'and'transverse'surface slopes or batter angles, this corresponds with a ground surface rotation about a longitudinal axis and a transverse axis of the bull-dozer, respectively.

Figure 1 illustrates a gradient indicator device 10 in its simplest form used in association with a bull-dozer 12, which is shown travelling along both a transversely sloped surface 14 and a longitudinally sloped surface 16. The device 10 comprises a curved gradient indication window 18 together with a number of visual increments 20 according to various commonly required batter angles. The transverse batter angle of the bull-dozer 12 shown in side view is 1: 6, as is displayed on the device 10 which is typically mounted within the bull-dozer carriage. Housed within the device 10 and window 18 is a transparent tube 22 of circular cross-section which contains a liquid 24 of suitable viscosity such as oil, and a solid object 26 such as a ball-bearing. When the surface 14 upon which the bull-dozer 12 is travelling is not flat or horizontal, the ball bearing 26 will travel through the liquid 24 and rest at the increment 20 corresponding with the gradient of the surface 14, due to the force of gravity. Thus, one may appreciate that this provides the driver of the bull-dozer with a real time visual indication of the slope of the surface being created.

It is to be understood that the device 10 need not necessarily include a tubular chamber as part of its visual indication. For example, the tube 22 may well have a square cross-section which may then result in a lower viscosity of fluid.

The increments 20 are defined by different batter angles. These preferably correspond with batter angles that are commonly used in the field. The following list of angles represent those most commonly required in the mining industry. The list also indicates the mining operations which require the construction of such gradients. BATTER ANGLE OPERATION ZERO ANY FLAT SURFACE 1: 3 FIRE BATTERS 1 : 6 REHAB BATTERS 1 : 10 RAMP BATTERS

It is to be understood that the device 10 of the present invention need not necessarily include the abovementioned increments which correspond specifically to mining operations. As will be shown in a further embodiment, the increments may well be made to suit the situation in which it is to be used. In addition, the increments need not be batter angle increments, but rather a precise or percentile indication of the gradient.

Illustrated in Figures 2-9 are three further possible variations of the gradient indicator device of the present invention. The device 28 of Figure 2 has a battery-powered lamp 30 externally mounted to the device while the devices 32 and 33 of Figures 3-9 have an alternate lighting means in the form of two LED lamps 34 and 36 which are mounted internally within the devices 32 and 33. These devices 32 and 33 further include a horizontal spirit level 38, the purpose of which is explained later below. The differences between the two devices 32 and 33 will also be described in further detail below. It is to be understood that in all four of the embodiments, like parts will be referred to using like numbers.

Referring now to Figure 2, the device 28 consists substantially of a rigid, rectangular body 40 having an indicator face 42 which includes the indication window 18, and a transparent indicator cover 44 secured thereto by the use of screws 46. In accordance with a second embodiment of the invention, the device 28 includes an externally mounted lamp 30 which is mounted to the device 28 for use at night or in areas that require further light so that the driver may adequately read the device. As can be seen, the lamp is adapted to shine light downwards onto the indication window indicator face 42.

Although not specifically shown with respect to the device 28, the internal layout of the device 28 can be appreciated when viewing Figure 5 which illustrates a third embodiment of the invention, that is, device 32. As can be seen, the body 40 is routed out so that a cavity 48 for the tube 22 is created. The cavity 48 and tube 22 include a curved portion that is visible through the indication window 18 of indicator face 42, and two end portions 50 and 52 that bend upwards, and which are not visible through the window 18. Once the tube 22 is filled with oil, these end portions 50 and 52 are sealed using sealant (not shown). The tube 22 may also be sealed using suitable plugs, as will become apparent in the final embodiment. The body 40 of the device 28 also includes four apertures 54 for receiving the screws 46, and an internal lip 56 for housing the indicator face 42 therein which is then sealed by the indicator cover 44.

The increments 20 are further indicated by recessed surfaces 58 disposed along and outwards from the indication window 18 of the indicator face 42. Alternatively, they may be screen printed on the indicator face 42. The body 40 of the device may easily be constructed by plastic injection moulding due to its relatively simple configuration. The transparent tube 22 is preferably constructed of acrylic tubing, but plastic tubing may also be used.

One can thus appreciate the ease at which the device 28 of the present invention may be constructed and assembled, as well as its effectiveness in indicating gradient to a driver of a bull-dozer or like equipment. The device 28 may be easily fixed to an internal surface of a bull-dozer carriage with the use of double-sided adhesive tape or any other suitable mounting means. It is common to use double- sided tape, as opposed to bolted connection or welds, as in most machinery you cannot drill or weld directly to the carriage cab, and therefore the window or other surface within the carriage must be used.

A further mounting means may be in the form of vacuum suction caps (not shown) located on each corner of the back surface of the device. The mounting means is not intended to be limited to any of the above examples.

Figures 3-5 illustrate a device 32 according to a second embodiment of the invention. In order to adequately indicate the level of gradient, the device must be mounted within the bull-dozer carriage precisely horizontally. In the case of the first embodiment, this may be achieved using a well known spirit level (not shown). The spirit level may be placed above the indicator device 28 which may then be manoeuvred until the spirit level indicates that the device has been mounted precisely on a horizontal plane. This task is somewhat tedious and the gradient indicator device 32 of Figures 3-5 attempts to simplify this procedure.

As can be seen, in place of the lamp 30 of device 28, a horizontal spirit level 38 is mounted within a further cavity 39 of body 40 of the device 32. Therefore, instead of the arduous task of using a separate spirit level in association with the indicator device, the two have been combined into the single unit 32 and therefore one may simply mount the device 32 to a surface by simple visual inspection whilst the bull-dozer is on a flat surface. As mentioned earlier, this device 32 includes two LED lamps 34 and 36 mounted adjacent upwardly extending ends 50 and 52 of the tube 22 respectively. These perform the same operation as the lamp 30 which is to simply provide a light source to the driver with respect to viewing the device when dark. These may be powered by any suitable battery means (not shown) in connection with wires 60 and 62 of LED lamps 34 and 36 respectively.

The abovementioned spirit level 38 is a very well known device which simply comprises a tube filled with a suitable liquid and having indications 64 marked thereon. Inside the tube is an air bubble 66 which when aligned between the indications, indicates that the level 38, and hence the device 32, is horizontally aligned. It is to be understood that other types of spirit level and lighting means may well be implemented.

Illustrated in Figures 7-9 is the final and preferred embodiment of the present invention. The gradient indicator device 33 includes substantially the same features of device 32 with some slight variations. The device 33 includes a body 68 having a recess 70 on its front side configured to receive an indicator face 72. The body 68 of device 33 includes three cavities 74,76 and 78. The top cavity 74 is

used in the same way that cavity 39 was used in device 32, that is, for mounting of a horizontal spirit level 38 therein. The middle cavity 76 is adapted to receive a tube 80 which differs slightly from tube 22 in that it does not include upwardly extending ends. Plugs 82 and 84 are used to seal the ends of the tube 80 which again houses fluid 24 and a ball bearing 26.

The lower cavity 78 comprises an upper horizontal portion 86, a lower horizontal portion 88, and two spaced apart mid-portions 90 and 92 each of which connect the upper and lower horizontal portions 86 and 88. The purpose of cavity 78 is to provide a housing for two LED lamps 94 and 96 as well as electrical wiring (not shown) associated therewith. As those skilled in the art would appreciate, the two LED lamps 94 and 96 are configured so that their respective shoulders 98 and 100 sit in the upper horizontal portion 86 of the cavity 78 and their respective bases 102 and 104 extend into mid-portions 90 and 92 respectively. The body 68 of the device 33 includes an aperture 106 extending from the side of the body 68 into the lower horizontal portion 88 of cavity 78 to thereby house a switch (not shown) which when pressed activates the LED lamps 94 and 96. The lower horizontal portion is adapted to house the wiring between each LED lamp 94 and 96 and the switch. Each of the abovementioned lighting means are preferably powered by a suitable battery.

The device 33 further includes more user-friendly visual indicia on the indicator face 72, namely, upper visual increments 108 indicating commonly required batter angles (the ratio between vertical and horizontal) and lower visual increments 110 indicating corresponding angles ranging from zero to twenty degrees. The indicator face 72 further includes an upper aperture 112 shaped and aligned with cavity 74 in the body 68 so that the spirit level 38 may be viewed therethrough, and a second aperture 114 shaped and aligned with cavity 76 in the body 68 so that the transparent tube 80 and ball bearing 26 located therein may be viewed therethrough. The gradient indicator device 33 in this case does not include a cover and is mounted within recess 70 in the same manner as previously described using suitable screws (not shown).

Illustrated in Figure 10 are two gradient indicator devices 116 and 118 that are mounted to an internal surface of a bull-dozer carriage 120. It is to be understood that the devices 116 and 118 may be any one of the devices embodying the present invention and described herein. By viewing the position of the ball-bearing 26 along the tube, a driver (not shown) sitting in the seat 122 may receive a real time indication of the longitudinal slope of the bull-dozer through visual inspection of device 116, and an indication of the transverse slope of the bull-dozer through visual inspection of device 118. Although not shown, a single device may well include a means of indicating both longitudinal and transverse slope in the one unit whereby two indicating means on the device are located at right angles to one other. In this situation, the device could be positioned in a corner of the bull-dozer carriage 120.

It should therefore now be apparent how the gradient indicator device of the present invention overcomes the various problems associated with previous devices, in its simplicity and effectiveness, and the ease in which the device may be manufactured and assembled. GPS systems for indicating gradient are not able to be used in underground operations whilst laser systems are very expensive. The present invention provides a more robust and easy-to-use device for indicating slope of machinery in real time, and may be used in both aboveground and belowground operations. As well as bull-dozers, the device of the present invention may be mounted within any type of vehicle used in creating a graded surface such as smaller vehicles like bobcats to larger industrial mining vehicles.

Further advantages and improvements may very well be made to the present invention without deviating from its scope. For example, the tube 22 may well have associated with it some form of sensing means which sounds an alarm when the gradient of the machinery is too high. Although the invention has been shown and described in what is conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope and spirit of the invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent devices and apparatus.

In any claims that follow and in the summary of the invention, except where the context requires otherwise due to express language or necessary implication, the word"comprising"is used in the sense of "including", i. e. the features specified may be associated with further features in various embodiments of the invention.

Dated this 4 March 2005 Brenton Pearce By his Patent Attorneys LESICAR PERRIN