AU623291B2 - Weight indication device - Google Patents

Description

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334820

AUSTRALIA

Patents Act FORM COMPLETE SPECIFICATI (ORIGINAL) j Application Number: Lodged: Complete Specification Lodged: Accepted: Published: tr r Ctr r r, FTt t i rtr:I 1 rtil rIe rt i I It r L I nlr t

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r It d c I r Itto Priority: Related Art: 1- Applicant(s): James Ylias Lot 17 Yippon Creek WAUCHOPE NSW 2446

AUSTRALIA

Address for Service: E 41

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I 1 I 4 ARTHUR S. CAVE CO.

Patent Trade Mark Attorneys Level 10, 10 Barrack Street SYDNEY NSW 2000 Complete specification for the invention entitled "Weight indication device".

The following statement is a full description best method of performing it known to me:of this invention, including the -1 5020 i

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WEIGHT INDICATION DEVICE The present invention relates to weight indication devices and in particular to such devices when used in relation to motor vehicles, particularly trailers, trucks, semi-trailers, and c4anes or other devices which undergo a loading/unloading operation such as weigh bridges.

In particular, the present invention relates to an improvement to a weight indication devic over that described in the applicant's prior Patent Application No. 77696/87.

Road and highway governing bodies such as the Department of Motor Transport, Department of Main Roads and the like, set various weight limits in relation to axle loads which are allowed to be carried by trailers and trucks upon public thoroughfares. Such loads and weights are usually examined by police authorities and main road authorities by the placing of f a scale on the ground such that the truck operator can then position a wheel of the truck upon said scale. If the axle 0 load is found to be in excess of the prescribed amount then very heavy fines are placed upon the operator and/or owner of the vehicle.

It is an object of the present invention to provide an a improvement to a weight indication device which will, for instance, help prevent overloading of axles during the loading up procedure.

In one broad form the present invention provides a weight indication device, adapted to indicate the weight of a load, -2 AMD/0220a i

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comprising: measuring means, connected between a load bearing means and a reference means, having at least one variable volume air bag filled with fluid, the volume of said air bag(s) being variable dependent on the pressure exerted on said air bag(s) by said load, and whereby said fluid is emitted through a fluid outlet into a fluid line; and display means, responsive to anc indicative of the pressure of said fluid, comprising a display container provided at a first end thereof with a fluid inlet connected to said fluid line and at a second end thereof with a vent to atmosphere, and, a display indicator being provided thereon such that the level of fluid within said display container indicative of the pressure of said fluid may be observed.

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The present invention is preferably for use by truck drivers to give an indication of the axial load before such time as exact measurement is required when stopped by Police or other authorities, however, Police and other authorities can utilise the present invention in a "black box" or "sealed unit" (to prevent tampering) which could be accessible by such authorities only via pass keys and the like. This would obviate the need for separate scales. However, primarily, the present invention is for the use of truck drivers, to give a general indication of the load placed upon the truck during the loading-up procedure. Alternatively, however, the present invention need not be limited to vehicle applications, for instance, the invention could be applied to weigh bridges or any other application wherein a loading and/or unloading operation occurs between a load bearing member and a reference point.

The present invention will become more fully understood from the following detailed description of preferred but non-limiting embodiments thereof in connection with the accompanying drawings; in which: Fig. 1 shows the weight indication device connected between the suspension components of a vehicle and the vehicle framework; Fig. 2 details a measurement shaft of one embodiment of a weight indication device; Fig. 3 shows a gauge for indicating the load as measured by the measurement shaft of the weight indication device; Fig. 4 shows a mechanical gauge for indicating the weight of the load as measured by the measurement shaft of the weight 3-' i/0220a

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1 111-- P**0 0. C C C indication device; Fig. 5 shows an elevational view of the weight indication device in use with a leaf-spring suspension system; Fig. 6 illustrates an alternative embodiment of a weight indication device; Fig. 7 details the connection between the weight indication device of Fig. 6 between the axle and the frame of a vehicle; Fig. 8 illustrates a display device which may be mounted on the cabin of the vehicle; Fig. 9 details an electronic circuit configuration illustrating an embodiment of a practical implementation of the present invention; Fig. 10 shows an example of a typical implementation for purging and filling the air bags; and, Fig. 11 shows an axle and frame of a vehicle with an air bag embodied therebetween.

In Fig. i, a weight indication device 1 is connected between suspension system 2 of a vehicle and the vehicle framework 3. The suspension system shown in Fig. 1 is of the leaf-spring type, consisting of a plurality of leaf-springs 4 shown positioned on or underneath an axle and differential system 5. A suspension system 2 of this type is generally affixed to the vehicular framework 3 by means of dampers or shock absorbers 6, between the axle 5 and the framework of the vehicle 3. The weight indication device 1 of the present invention is thus connected in parallel to the shock absorbers 6 such that the relative displacement between the vehicle -4- 2 framework 3 and the suspension components 2 can be measured to give an indication of the weight of a load which is placed on the vehicle framework 3.

The weight indication device of the present invention is comprised of two core components, a measurement means, and a display means. The measurement means is located adjacent the suspension components of the vehicle, whilst the display means 00 9 0 o 00 o 0 0 1 0 *L 0 0 0 0e 0c~ 0 00 4a AMD/022Oa is located in a convenient position, for instance, in the cabin of the vehicle or along the side of the vehicle.

A first embodiment of a measurement shaft of the weight indication device 1 in accordance with the invention described in the applicant's prior Patent Application No. 77696/87 shown in Fig. 2, and cosists of a main body 7 filled with an incompressible fluid 8 surrounding a spring 9. Through one end of the main body 7, is provided a piston 10 which extends through a piston shaft 11. The end of the piston within the main body 7 is provided with a piston head 12 which extends substantially to the inner surface of the main body 7, and is provided with a fluid-tight seal 13 on its outer circumference. The lower end of the piston shaft 11 may be connected to the suspension system of a vehicle by a pin 14, and the upper end of the main body is connected via a pivoted member to the frame-work 3 of the vehicle.

As the vehicle is loaded, the spring 9 within the main body 7 of the measurement shaft is compressed by the piston head 12 of the piston 10. The volume of fluid within the main body 7 is decreased as the fluid flows through the opening to a pressure gauge, two possible embodiments of which are shown in Figs. 3 and 4. The pressure of the fluid 8 within the main body 7 of the measurement shaft will be proportional to the applied load on the vehicle framework, and this pressure is transmitted without loss through the fluid to the pressure gauge which contains a suitable indicator calibrated in terms of the weight of the load, as hereinafter described. The connections between the measurement shaft of the weight indication device and the vehicle framework and suspension -5 Niio11 i Z D/0220a 4. 4 Ak' system are made by pins which preferably allow the connection points to hinge. That is, the lower end of the piston shaft II is provided with a pin 14 which may be connected to the suspension system 2, and the upper end of the main body is connected through two pints 16 and 17 to two members 18 and 19. Thus, with member 19 firmly affixed to the vehicle frame 3 by the anchor bracket 20, the pins 16 and 17 allow the member 18 to rotate such that rotational movement of the suspension system 2 relative to the vehicular frame 3 is allowed as the vehicle travels over its typically non-uniform path. Each of o SA the pins 14, 16 and 17 therefore allow rotational pivoting of 808e the measurement shaft of the weight indication device whilst not allowing upwards or downwards pivoting. Therefore, all upwards and downwards movement is transmitted through the 00W7 i piston movement of the measurement shaft of the weight indication device.

-The above-identified weight indication device is S described and claimed in the applicant's prior Patent ~Application No. 77696/87.

A further alternative measuring means to which the a improvement of the present invention is directed is the 'air bag'. Such an air bag may once again be positioned adjacent or.

Sin parallel to the suspension components of the vehicle between the frame and the axle, the load and the axle, or the load and the frame, or, in broad terms, between a load bearing member and a reference. Such a device is known to persons skilled in the field, being constructed of a flexible plastics material, and able to withstand relatively high pressures. Although the 6 AMD/0220a I I~ 1

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term 'air bag' is utilised herein, it will be understood by persons skilled in the art, that any 'fluid' may be utilised therein. A 'fluid' should be understood to include any liquid or gaseous substance. The use of an air bag instead of the slightly more complex pressure gauge eliminates a number of moving mechanical parts and leads to a more inexpensive embodiment of the present invention.

The weight of the applied load may be monitored and displayed by a gauge, embodiments of which are shown in Figs.

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C 6a AMD/0220a r- i- In Fig. 3, the guage 21 is of the well known manometer type in which the hydrostatic pressure of the incompressible fluid, or its level, is indicated by the gauge. The incompressible fluid travels through the inlet 22, the height of the fluid, which is proportional to the pressure, being observed through the window 23. The top of the pressure gauge is provided with a breather hose 24 which is open to the atmosphere, atmospheric pressure thus being used as a reference pressure.

A non-return valve is preferably located between the measurement shaft of the weight indication device 1 and the pressure gauge 21 such that as the load is increased and the fluid is forced from the main body 7 of the measurement shaft.

S to the pressure gauge 21, fluid flows through the one-way valve 0I* t to indicate the increasing weight of the load, but, if the vehicle rocks, this movement will not cause the fluid to travel up and down within the pressure gauge making it difficult to read the indicator. A tap may be provided in parallel with the one way valve to allow the fluid to flow back to the weight indication device after unloading of the vehicle and before reloading takes place.

Sa, An alternative pressure gauge is shown in Fig. 4. This pressure gauge 25 is of the ratchet and pinion type, such that rotation of a toothed wheel 27 through its engagement with the teeth of a bar 28 which is connected to the piston 29, causes a pointer on a metering device to rotate and indicate the weight of an applied load on a vehicle. The incompressible fluid 8 flows'into one end of the housing, 30 of the pressure gauge through the opening 26. The piston, slidable on the rod 33, is -7 1142E contained within the housing, and provided with a seal on its outer circumference inside the inner surface of the housing The other end of the piston 29 is provided with teeth 31 which interlock with the teeth 32 of the whew. 27. The gearing mechanism 34, comprising the toothed wheel 27 and the ratchet 31 is contained within a housing A spring 36 surrounds the other end of the piston 28 between the piston head 37 and the housing 35 such that the pointer will automatically rotate back to zero position when no ,q load is applied to the vehicle. A gearing mechanism 34 may be t provided such that the pointer will indicate the applied load

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weight on an appropriate scale. As the load weight is I increased, the piston 10 of the measurement shaft of the weight indication device 1 forces some of the incompressible fluid 8 to leave the main body 7 through opening 15 and through inlet 26. The piston 29 then moves against the action of the spring 4 36 so that the teeth 31 of the ratchet 28 engage with the teeth 32 of the pinion 27 to rotate the pointer 38 on the face of the r device to indicate the weight of the load.

t{ t TV, The way in which the weight indication device 1 of the r present invention is connected to a leaf-spring suspension system and framework of a vehicle is shown in Fig. 5. The suspension system 2 is comprised of a plurality of leaf springs 4 positioned underneath an axle 42, held together with U-bolts 41 and plate 40. Pin 14 connects the measurement shaft of the weight indication device 1 to the plate 40, allowing a small degree of rotation. Bolts 39 secure the top of the measurement shaft of the weight indication device 1 to the vehicle frame -8- 1142E Ix--

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3. The opening 15 is connected to the pressure gauge via a tube or the like. The pressure gauge may be located in suitable position inside or outside the chasis of the vehicle.

In Fig. 6 is shown an alternative embodiment of a weight indication device which was described in the applicant's aforementioned Patent application. In this embodiment, the measurement shaft 43 is connected at its lower end 44 to the axle of a vehicle, and at its upper end 45 to the frame of the vehicle. The cylinder 46 is filled with fluid, which is compressed by the piston 47 in the same manner as hereinbefore described upon loading of the vehicle. As the piston 47 rises, S the fluid is forced out of the outlet 41, through the pressure line 49 and into the chamber 50 of a tens. adjustment unit .51. The tension adjustment unit 51 allows operator adjustment and calibration of the weight indication device of the present invention, such that a pressure gauge 52 may be calibrated.

I The tension adjustment unit 51, cosists of a container 53, provided therein with a movable piston 54 which is positioned over the fluid chamber 50, and sealed therefrom by a cupped seal 55. A spring 56 is connected to the top of the piston 54, and underneath an adjustable stopper 57. The adjustable stopper 57 may be raised or lowered within the unit 51 such that the spring 56 may be compressed or expanded. A breather vent 58 is provided such that the spring 56 may be compressed or expanded, the upper part of the container 51 being vented to atmosphere. By means of a "T-junction" 59, the pressure line 49 is also connected to the pressure gauge 52, which may be calibrated in any desirable means. For instance, the pressure gauge may be calibrated in terms of KPA 9 E i (pressure), kg (weight of load), or by a simple colour code which indicates low, normal and excess loading of the vehicle.

A warning device 61, for instance a light or an alarm may also be connected to the pressure line 49 via a suitable pressure switch 60. Th<- advantage of this embodiment of the weight indication device of the present invention, is that it allows operator calibration of the device by simply adjusting the position of the stopper 57 to consequently alter the tension of the spring 56 at different specified weights.

0. Preferably, in order to eliminate shocks and the like from .f affecting the readings of the device, a damping means 63 is provided in the measurement means 43. The damping means 63 of Fig. 6 consists of a cushioning material 64 being interfaced between a plate 65 attached to the -iston shaft and the piston 47, the plate 65 being provided with at least one air vent 66.

Therefore, if the piston shaft is suddenly forced downw rds, then the piston itself is not rapidly sucked down, thus I t obviating the possibility of an air bubble being created in the fluid. also, this construction provides a more stable reading Or on the gauge 52.

The weight indication device of the present invention as herein described can therefore be implemented in a variety of forms. Likewise, depending on the particular vehicle type and load to be carried, the location of the weight indication device may be altered. As discussed, Fig. 5 showed the device 1 connected between the leaf suspension system and the framework of a vehicle. In applications wherein the vehicle is likely to be loaded in a sloping condition, then it may be 10 1142E preferable to provide a pair of measuring devices, one on each side of the longitudinal axis of the vehicle. In this situation, the reading on the pressure gauge should be arranged to give one average reading together with an indication to the operator that the load is unevenly distributed. It may, for instance, be preferable to provide completely separate weight indication devices on each side of the vehicle.

Further, a number of measurement means may be connected in 'series' by a suitably hose and connected to a single gauge to 3 provide an average reading. For instance, in the case of a t vehicle with a plurality of axles that are all load sharing, a *o o single gauge may be provided which will display an average weight of the load of the vehicle.

In Fig. 7, is shown a weight indication device connected between the centre of an axle and the centre of the frame of the vehicle. Fig. 7 shows the embodiment as displayed in Fig.

et 6, with the measurement shaft 43 connected in a substantially central position of the vehicle between the axle and the frame, and the tension adjustment unit 51 connected at any convenient point. The gauge 52 may be located, for instance, in the chasis or on the exterior of the vehicle.

t In Fig. 8 is shown a preferred embodiment of a display device which may be mounted in the cabin of the vehicle. The display device, generally designated by the numeral 70 is shown provided with a number of switches 71, 72 and 73 and a 'Christmas Tree' of lights 74. A set of digital numbers may alternatively be provided, if required. A set of operating instructions 75 may also be conveniently provided on the front 11 1142E i

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of the display device 70. The display device 70 is operated from a voltage source 76, and may optionally be provided with a further 'Christmas Tree' of lights 77 at a remote position, for example on the side or the rear of the trailer, in an easily accessible position during the loading operation of the vehicle. The measuring means 78 is connected to the display means 70 by an interconnecting cable. The measuring means 78 comprises the measurement shaft or air bags 79 and the operable air supply 80 connected thereto.

3 In operation, before the loading of the vehicle commences the operator'initiates a 'calibrate' cycle where the air bags '.ee 79 are purged and then pressurised to a small (10KPA) value.

The operator then loads the vehicle with a known goods weight t distribution which will then become the reference load. The t t operator now initiates a 'store load limit' cycle where the pressure of each air bag group is stored in a memory of the controller. The system is now ready for use. While loading a 'Christmas Tree" of lights indicates to the operator the increase in axle load with respect to the previously stored )3 limited. The 'Christmas Tree' of lights illustrated in Fig. 8 c progresses from green to green to green to amber to red to all t flashing in the manner of a bar graph to indicate load increase. These lights will be light emitting diodes (LED's) on the control unit 70, and an external group of lights 77 of any preferred construction will be able to be interfaced. A typical configuration of operation will be such that, in operate mode, the lower green light will be constantly illuminated and will flash while the controller is performing a -12 11.42E function such as calibrate or store, and will stop flashing to indicate ready to load. If a fault condition such as an air leak is detected, the the top red LED will flash constantly until the fault condition is cleared'and the green LED will indicate the nature of the fault.

If more than one group of axles is to be monitored then each group will be displayed at 3 second intervals and another light or LED at the top of the 'Christmas Tree' will indicate which axle group is being displayed. The stored value will 0 preferably be retained by the unit when power is disconnected.

S 6 In Fig. 9, is detailed an electronic circuit, configuration illustrating a preferred embodiment of the display means of the present invention. The display device 81 comprises electronic circuitry for processing the data received from the measuring means 82, as well as indication means 83 to display the weight of the load on the vehicle. The electronic circuitry comprises a controller 84, for example, a motorola MC146805E2 CMOS Ott, C microprocessor to receive the input data from the measuring means 82 via an analog to digital converter. The A/D converter i 85 may, for example, be a National ADC 0808 Analog to Digital Converter which converts the analog output from the pressure GO transducers of the measuring means 82 to a digital signal compatible to be inputted to the microprocessor unit 84. The microprocessor is also adapted to control the flow of air into and out of the measuring means via means of a set of switches 86 and control lines to the solenoid valves 87. The set of swil-ches 86 are provided as on the display means 70 of Fig. 8, specifically, an 'operate' switch 71, a 'calibrate' switch 72, 13- S1142E 1 1 1 1 1 r y i 4, 1 4 4 r *9l: 4 .4.4 4444 4*i 4. S o 4i 4 4 4*4 4

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*I s 4i 4 4 44 4 *i 4 and a 'store' switch 73. Selection of these switches 86 operates the 'purge: and 'calibrate' solenoid valves 88 and 89, respectively. The operation of these valves is more clearly depicted in Fig. 10 which illustrates the functional connection thereof. Each of the display LED's 83 is connected to the microprocessor 84 by means of an open collector transistor driver circuit, depicted as shown by reference numeral 90. The memory will be via an EEROM.

In Fig. 10 is illustrated a typical connection to the measuring means, for the supply and release of air pressure therein. Utilising 'air bags' 91 for the measuring means, the purge valve 92 and calibrate valve 93 may be connected to supply and release the air from the air supply 94. A valve may be provided such that regulation of flow is ensured. The pressure in the air bags is monitored by means of pressure transducers 96 connecting the system to the microprocessor via the analog to digital converter.

In Fig. 11 is illustrated an axle and a frame of a vehicle with an air bag 97 embodied therebetween. The air bag 97 replaces the piston-type measurement device 47 of Fig. 7.

An adjustment unit 51 may optionally be utilised. Obviously, the air bag need not be supplied between the axle and the frame of the vehicle, but could alternatively be supplied in a variety of positions on the vehicle such as between the load and the frame. In non-vehicle applications the air bag is supplied between the load and a non-moving reference point.

Numerous modifications can be made to the device which can improve the versatility of the embodiments described 14 AMD/0220a 4 i c, i herein. For example, an electrical switching device may be installed to activate either an audible or visual signal such as a horn or indicator lights on the vehicle or vehicle can to indicate when the maximum load has been attained.

Any suitable fluid may be utilised in the weight indication device of th3 present invention. Preferably, fluids with low compressibility are utilised, such as oils and the like, however, any gaseous or liquid fluid, for instance, air, may be utilised.

It will become apparent to those skilled in the art, that numerous variations and modifications can be made to the embodiments as herein described without departing from the overall spirit and scope of the present invention.

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Claims (4)

1. 2. A weight indication device as claimed in claim 1, wherein said air bag is connected between a frame of a vehicle and an axle of said vehicle or adjacent suspension components of a vehicle, such that said air bag may vary in volume, in response to displacement between said frame and said axle or between said suspension components, respectively.
2. 3. A weight indication device as claimed in claims 1 to 2, wherein said display means comprises a longitudinal vertically disposed container, and wherein said display indicator consists of a window in one side thereof such that the level of fluid within said container may be observed therethrough.
3. 4. A weight indication device as claimed in any one of 16 AMD/0220a ,I L 'claims 1 to 3, wherein said display means comprises a longitudinal cylinder separated into two chambers by a movable piston, a first of said chambers being provided with a fluid inlet connected to said fluid line, said piston having a piston shaft extending through a second of said chambers provided with a set of teeth which interengage with a set of teeth provided on a pinion wheel, said pinion wheel being connected to an indicating device for display of pressure of said fluid in said first chamber. A weight indication device as claimed in claim 1, further comprising a tension adjustment means connected via a fluid line between said measuring means and said display means such l that the pressure fluid in said fluid line may be reduced. A weight indication device as claimed in claim 5, wherein said tension adjustment means comprises a longitudinal container with a movable piston provided therein separating said container into two chambers, a first of said chambers having a fluid inlet connected to said fluid line, a tension spring being provided in a second of said chambers between said piston and an adjustable stopper, wherein the position of said r stopper may be moved within said second chamber to consequently adjust the tension of said tension spring.
4. 7. A weight indication device, substantially as herein described with reference to Figs. 1, 3 to 5, and 7 to 11 of the accompanying drawings. DATED this 14th day of January, 1992. JAMES YLIAS By His Patent Attorneys ARTHUR S. CAVE CO. 17 AMD/0220a i 'i T