WO2012077083A2

WO2012077083A2 - Self propelled vehicle

Info

Publication number: WO2012077083A2
Application number: PCT/IB2011/055575
Authority: WO
Inventors: Paulus Johannes Aucamp
Original assignee: Agricultural And Industrial Mechanisation Group (Proprietary) Limited
Priority date: 2010-12-09
Filing date: 2011-12-09
Publication date: 2012-06-14
Also published as: ZA201109077B; WO2012077083A3

Abstract

The invention concerns a self-propelled vehicle (10) for use in the mining, industrial and/or agricultural industry. The vehicle is typically a hauler, grader or container handling vehicle and includes a modular chassis (20) comprising at least a forward section (22) and a rear section (24) which are detachably connectable to each other by means of complementary connecting means (30) located on each section. The vehicle (10) has a cabin (40) which has a roll-over protection structure and a fall on protection structure. Ideally the cabin (40) also includes an internal module (51) defining a seating arrangement which has at least one seat for an operator. The cabin (40) is also detachably connectable to the chassis (20) so that it is replaceable as a single unit. The vehicle (10) further includes a pneumatic gearshift and pneumatic fail-safe brake system which meet the safety requirements for operation underground in a mine.

Description

SELF PROPELLED VEHICLE

BACKGROUND TO THE INVENTION

This invention relates to a vehicle. In particular, but not exclusively, this invention relates to a self propelled vehicle for use in the mining, industrial and/or agricultural industry.

It is well known that conditions underground in a mine are such that vehicles which are normally used above ground are not suitable for use underground. Above-ground vehicles are not only unsuitable for use underground as a result of the height and road width constraints, but also as a result of the strict safety requirements such as the fire-proofing requirements that have to be complied with before being allowed in a mine. Traditionally, one way of addressing this issue has been to convert above ground vehicles into underground vehicles by replacing unwanted or unsatisfactory components until the vehicle complies with all of the safety requirements. Converting above-ground vehicles into underground vehicles is often a difficult and expensive exercise. From a safety point of view, visibility of the driver in underground vehicles has traditionally been one of the primary concerns. Due to the fact that the vehicles are not optimised for use underground the driver's position is such that his visibility is often impaired. Known flame-proof tractors used in underground applications usually have a forward extending nose section which can limit the forward visibility of the driver. Also, the seating arrangement of the driver and/or operator generally cannot be optimised due to the position of the vehicle's operating controls being fixed. Apart from the visibility concerns, the driver's unfavourable seating position may further cause the maximum height requirements to be exceeded.

Apart from the problems being experienced with regard to the safety concerns mentioned above, problems are also experienced with excessive noise levels and ineffective ventilation in the vehicle's cabin. It is generally required of the driver to wear safety equipment such as noise reduction headgear while operating the vehicle to reduce the noise levels. In many existing vehicles the cabin cannot be isolated effectively as a result of the number of openings in the cabin required for the vehicle's operating controls. In some of these vehicles, the controls are mechanical, electrical, pneumatic and hydraulic and, as a result, numerous openings are required to accommodate the lines feeding the controls. Another disadvantage of the openings in the cabin is that it is often problematic if not impossible to achieve effective ventilation.

Vehicles currently used in the mining and agricultural field normally also include a power take-off (PTO) to drive other equipment and implements connected thereto. Generally the PTO is in the form of a splined shaft and is mechanically coupled to and driven off the drive train of the vehicle. Due to the harsh conditions in which these vehicles operate, the rotation of the shaft is often obstructed by objects or debris such as sand and stone. Striking these obstructions may cause substantial damage to the internal components of the dive train, for example to the clutches and transmission. In the event of damage being suffered it is required that the vehicle be stripped and the necessary components fixed or replaced. This is normally a complex and time consuming procedure which may take days to repair the vehicle completely. Servicing of the known vehicles is further hampered by the difficulty of getting access to the damaged parts seeing that the chassis cannot be disassembled.

In an underground mining situation, the overall length of the vehicle is of importance as a result of the space limitations. The overall length of existing vehicles is often problematic when equipment is hauled around. One example of a piece of equipment that is often hauled underground is a container handling apparatus, as described in South African patent 68/6139, in the form of a trailer, which has been marketed successfully for many years under the trade mark "Power X". Typically the overall length of the vehicle and trailer is about 11m. This overall length limits the ability of the vehicle to manoeuvre in areas where there is limited space. Also, as a result of the limited size of mine shaft conveyances it is usually necessary, when the container handling apparatus is to be deployed at a different level in the mine, to unhitch the apparatus from the tractor at one level and transport the tractor and container handling apparatus separately to the new level where the container handling apparatus must be rehitched to the tractor, or alternatively for the container handling apparatus only to be transported to to the new level where it can be hitched to a different tractor at that level. In either situation, the unhitching and hitching operations are dangerous for the personnel, who carry out these operations, typically from a position between the tractor and the container handling apparatus.

Yet another problem with the existing arrangements is that the articulated connection between the tractor and container handling apparatus can make it difficult in areas with limited space to reverse the container handling apparatus accurately relative to a container which is to be picked up and transported. The limited headroom available in such situations means that the driver of the flame-proof tractor also has limited rearward visibility, and this can make the reversing operation that much more difficult. One further problem with the existing tractor-trailer type vehicles is that the tractor is uncomfortable for the driver and can be driven at limited speeds only. This, together with the fact that the articulated connection can be quite unstable, means that container transportation is rather slow even in areas where higher speeds would be appropriate.

It is an object of this invention to alleviate at least some of the problems experienced with existing vehicles.

It is a further object of this invention to provide a self propelled vehicle that will be a useful alternative to existing vehicles.

SUMMARY OF THE INVENTION

According to the invention there is provided a self-propelled vehicle for use in the mining, industrial and/or agricultural industry, the vehicle including:

a modular chassis comprising at least a forward section and a rear section which are connectable to each other by means of complementary connecting means located on each section;

a cab comprising a roll-over protection structure and a fall-on protection structure, the cab having a seating arrangement suitable for accommodating the driver;

wherein the cab is detachably connectable to the chassis and replaceable as a single unit.

The vehicle may include a gearshift for selecting different gear ratios in the vehicle's transmission and a fail-safe brake system, the gearshift and failsafe brake system being either pneumatic or hydraulic, thereby allowing the interface between the gearshift and operating controls of the fail-safe brake system in the cab and a high pressure fluid source on the chassis to be either pneumatic or hydraulic in order to reduce the number of connections in the interface between the cab and chassis so that the cab may be easily detached from the chassis as a single unit.

The gearshift and fail-safe brake system are preferably both pneumatic so that the interface between the high pressure air source on the chassis and the gearshift and controls of the fail-safe brake system on the cab is purely pneumatic.

The forward and rear sections of the chassis are preferably detachably connectable to each another so that the chassis may be taken apart by disconnecting the complementary connecting means.

The chassis preferably comprises three sections, namely front and rear sections which are connectable to one another to form a major part of the chassis and a support section which is detachably connectable to the rear section.

The rear axle of the vehicle may be located on the rear section of the chassis in a position wherein direct access thereto is gained, by removing the support section.

The chassis preferably defines a space wherein a portion of the cab is received when connected to the chassis so that the cab is at least partially sunken into the space defined by the chassis in order to lower the seating position of the driver.

The chassis may include two main beams running along the length of the chassis, the beams defining the cab receiving space between them.

The beams are preferably split into front and rear portions which form part of the front and rear sections of the chassis respectively, wherein the connecting means are located at the ends of the front and rear portions of the beams that face each other when the chassis is assembled. The cab may have an internal module defining the seating arrangement, the internal module preferably being replaceable as a unit so that it may be replaced by another internal module when the cab is detached from the chassis.

The cab preferably has a frame including a number of legs which are connected to a top section which, in use, caries a roof, the legs being detachably connectable to the chassis.

The legs of the frame may be connectable to the chassis by means of bolts.

The vehicle may include a fail-safe brake system for use in combination with a service brake system of the vehicle, the fail-safe brake system comprising:

a high pressure fluid source for supplying fluid to the fail-safe brake system;

a protection valve splitting a feed line running from the high pressure source into at least two independent fluid flow circuits, one being a primary circuit including braking means for braking the vehicle when the fail-safe brake system is activated and the other being an auxiliary circuit for controlling fluid flow to the primary circuit; and

a control valve located in the auxiliary circuit for controlling the activation and deactivation of the fail-safe brake system;

wherein the fail-safe brake system may be activated and deactivated independently of the service brake system of the vehicle, thereby allowing the braking means to function independently of the service brakes of the vehicle.

The fail-safe brake system is preferably a pneumatic system.

The vehicle may include a gearshift for a transmission of the vehicle, the gearshift comprising a body, a valve bank having a number of outlets which, in use, are in fluid communication with actuators on the transmission responsible for selecting different transmission ratios, and a selector for controlling the flow of fluid to different valve outlets, the selector being movable between a number of positions which allow different fluid flow paths through the valve bank in order to activate and deactivate different actuators depending on the valve outlets to which fluid is supplied, thereby engaging and disengaging different gear ratios in the transmission.

The gearshift is preferably pneumatically operable.

Te vehicle may be a hauler, grader or container-handling vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings in which:

Figure 1 shows a perspective view of a self propelled vehicle according the a first embodiments on the invention;

Figure 2 shows a perspective view of a modular chassis of the vehicle of Figure 1 ;

Figure 3 shows a perspective view of a cabin assembly of the vehicle of Figure 1 ;

Figure 4 shows a perspective view of an interior module including seating arrangement of the cabin of Figure 3;

Figure 5 shows a perspective view of a second embodiment of a self propelled vehicle according to the invention;

Figure 6 shows a perspective view of a rear axle of the vehicle shown in Figure 5; Figure 7 diagrammatically illustrates a third embodiment of a self propelled vehicle according to the invention.

Figure 8 shows a left side perspective view of a gearshift of the vehicle according to the invention;

Figure 9 shows a right side perspective view of the gearshift of the vehicle according to the invention;

Figure 10 shows a rear perspective view of the gearshift of the vehicle according to the invention;

Figure 11 shows a diagrammatic representation of a fail-safe brake system of the vehicle according to the invention; and

Figure 12 shows a perspective view of braking means of the fail-brake system of Figure 11.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENT

Figure 1 shows a perspective view of a self propelled vehicle 10 according to the invention. The vehicle in Figure 1 is in the form of a hauler for hauling various equipment underground in a mine. The hauler 10 includes a modular chassis 20 and a cabin 40.

The modular chassis 20 can be seen in Figure 2. From this figure it can be seen that the chassis 20 includes a first section 22 which in use is a front section and a second section 24 which in use is a rear section.

Two primary beams 26 and 28 run substantially parallel next to each other along a major part of the length of the hauler 10. The beams 26 and 28 are each split into a front portion 26.1 , 28.1 and a rear portion 26.2, 28.2, thereby allowing the chassis to be of modular design. Attached to the front and rear portions of the beams are complementary connecting means 30 which in use connect the front section 22 of the chassis to the rear section 24. In the illustrated embodiment the connecting means 30 is in the form of connecting plates which are welded to the ends of the front and rear portions of the beams 26 and 28 and secured to one other using bolts and nuts (not shown). It should be clear that the chassis 20 can be split by simply removing the bolts and nuts and moving the front and rear sections 22 and 24 apart.

The cabin 40 of the vehicle is located on the rear section 24 of the chassis as shown in Figure 2 and includes a roll-over protection structure (ROPS) and fall-on protection structure (FOPS). These terms will be familiar to a person skilled in the art of mining and/or agricultural vehicles. The cabin 40 has a frame 42 which includes a number of legs 44.1 to 44.4 and a top section 46 to which the legs are connected. In use, the top section carries a roof 48. The frame assembly 42 is shown in Figure 3. In order to comply with the ROPS/FOPS requirements for use in a mine, the frame 42 is manufactured from hollow steel sections which are either welded or bolted to one another, while the roof 48 is in the form of a steel plate which is also either welded or bolted to the top section 46. As shown in Figure 3 there are connecting members 50.1 to 50.4 attached to the ends of the legs 44.1 to 44.4. In the illustrated embodiment the connecting members 50 are in the form of end plates which may be connected to the chassis 20 of the vehicle. The end plates 50 are welded to the legs 44 and in use are bolted to the chassis.

Apart from providing the necessary ROPS and FOPS protection the design of the cabin 40 is of such a nature that the cabin can be replaced as a single module. By simply disconnecting the frame 42 from the chassis 40, the cabin can be removed from the vehicle and replaced with another cabin. Figure 4 shows an example of an interior module 51 including the seating arrangement of the cabin 40 which, in this particular embodiment, provides space to accommodate a driver and a single passenger on two separate seats 52.1 and 52.2. To lower the positions of the seats 52 and as a result the overall height of the vehicle 10, the chassis 20 defines a space 54 wherein at least a portion of a base 56 of the cabin's floor is received so that the cabin is at least partially sunken into the chassis. The space 54 in the chassis is provided between the beams 26 and 28. It should be clear that as a result of the lowered seats 52, the overall height of the vehicle can be reduced so that it is capable of being used underground. In an alternative embodiment not shown in the drawings the internal layout of the cabin 40 can accommodate at least two passengers in addition to the driver. It is also envisaged that low profile seats may be used in the cabin to increase the comfort for the occupants. The design of the cabin 40 allows it to be economically improved compared to vehicles currently being used in the mining, industrial and/or agricultural industry.

From the above description of the cabin 40 it must be understood that the interior module 51 may be replaced by simply disconnecting the frame 42, removing the interior module and inserting a new interior module. As a result, the interior module is completely interchangeable.

As a result of the modular design of the vehicle 10 it must be understood that the cabin could be positioned anywhere on the vehicle and the orientation of the cabin could also be changed. Typically, the position and orientation of the cabin and, as a result, the position and orientation of the operator would be based on the particular requirements of the type of vehicle. For example, in the hauler 10 or grader 60, the operator is positioned between the vehicle's front and rear axles, while in a third embodiment the operator is positioned in front of the vehicle's front axle as described below. It is also envisaged that in yet another alternative embodiment the cabin could be located behind the vehicle's rear axle or between the vehicle's transmission and drive shaft. Considerations such as safety, visibility and the location of the operating controls, e.g. operating controls for external equipment such as cranes, may play a role in the desired position and orientation of the cabin and operator.

Before discussing further safety aspects of the hauler 10 and in particular the cabin 40 it is necessary to turn to the hauler's transmission (not shown in the drawings). The hauler 10 has a solenoid activated powershift transmission which has a gearshift 210 which activates solenoids located on the transmission pneumatically to engage and disengage specific gear ratios. The gearshift forms the subject matter of the applicant's co-pending international patent application PCT/IB2011/055481 entitled "Gearshift". The gearshift 210 will now be described in detail for ease of reference.

Figure 7 shows a perspective view of the gearshift 210. Although in this description the gearshift will be described as being pneumatic, it must be understood that a fluid other than air may also be used. For example, it is envisaged that in an alternative embodiment the gearshift 210 could also activate a powershift transmission hydraulically.

Returning to the illustrated embodiment, the gearshift 210 has a body 212 holding a valve bank 214 which has a number of distribution valves 216. In this embodiment the valve bank 214 includes three valves 216.1 , 216.2 and 216.3. Each valve has an inlet 218 and two outlets 220 and 222 which are in fluid communication with corresponding actuators on the transmission responsible for selecting different transmission ratios. In the preferred embodiment the actuators are pneumatically activated solenoids which in turn activate hydraulic clutch packs in the transmission in order to select different transmission ratios. A person skilled in the art of powershift transmissions will be familiar with the way in which the different transmission ratios are selected and accordingly it will not be discussed in any detail.

Air flow through the different valves 216 is controlled by a control mechanism 224 including a gear lever 226 which is movable between a number of different positions in order to direct air flow to different valves outlets 220, 222. It should be clear that by manipulating the gear lever 226 between its different positions the driver may change the gear ratios in the transmission as a result of different fluid flow paths activating different solenoids. In the preferred embodiment the gear lever 226 has five different positions namely first gear, second gear, third gear, neutral and reverse. It is envisaged that in an alternative embodiment the gear lever 226 may have a sixth position which corresponds to fourth gear.

As shown in Figure 7 the gear lever 226 is mounted on the end of a locating shaft 228 which is attached to the body 212 by means of bushings 230.1 and 230.2. The shaft 228 is located rotatably in the bushings 230 to allow it to rotate as the lever 220 is rotated. Also attached to the shaft 228 is a connecting member 232 which in turn drives a selector 34. The selector 234 is movable in a channel 236 which in use extends substantially horizontally between two guides 238 located on top of the valve bank 214. Fasteners 240 are used to connect the guides 238 and valves 216 to the body 212. In order to translate the rotational movement of the lever 226 into linear movement of the selector 234 in the channel 236, linkages 242 are connected between the selector by and connecting member 232 by means of fasteners 244. In the preferred embodiment the linkages 242 are bolted to the connecting member 232 and selector 234 so that they may rotate about a longitudinal axis of the bolts 244 as the selector is moved.

By moving the gear lever 226 between its different positions, the selector is moved along the channel 236 (shown in Figure 8) between different positions wherein air flow is allowed to different valve outlets. The selector 234 has activating formations (not shown in the drawings) located on a surface which is in use a bottom surface. The activating formations extend towards the valves 216 and interact with corresponding selection pins (not shown in the drawings) located on the valves in order to activate and deactivate the valves 216 as the selector slides along the channel 236 between its various positions. In the preferred embodiment each valve 216 has two selection pins, one associated with each valve outlet 220 and 222. ln the preferred embodiment the valves 16 in the valve bank 214 are normally open valves and in order to stop air flow to a particular valve outlet the corresponding selection pin has to be depressed, i.e. pressed downwards, by the corresponding activating formation located on the selector 234. It should be clear that air flow to the valve outlet or combination of valve outlets corresponding to the selection pin or combination of selection pins which is depressed is prevented. In contrast, air flow is allowed to the outlet or combination of outlets corresponding to the selection pin or combination of selection pins which is released, i.e. not depressed, thereby activating the solenoid or solenoids in fluid connection with the outlet(s).

The selector 234 is also used to control the activation and deactivation of a park brake of the vehicle by controlling air flow to a park brake outlet on the valve bank. Again, the park brake outlet is in fluid connection with a park brake solenoid responsible for activating and deactivating the park brake. The gearshift is designed so that air supply to the valve outlets is cut off upon activation of the park brake, thereby discharging all of the solenoids in order to disengage all gears in the transmission. It must be understood that upon activation of the park brake the vehicle will also be brought to a standstill.

As a safety precaution the park brake may only be activated when the gearshift is in its neutral position i.e. when the gear lever 226 is positioned in a generally vertical direction as shown in the figures. In the preferred embodiment the park brake is activated automatically upon movement of the gear lever 226 and accordingly the selector 234 into their neutral positions in order to bring the vehicle to a complete standstill every time the transmission is shifted into neutral. From the above description it should be clear that all of the selection pins are activated i.e. depressed when the selector 234 and therefore the gearshift 10 are in neutral.

The advantage of activating the park brake prior to shifting the transmission into reverse is that the direction of travel of the vehicle cannot be changed without first bringing the vehicle to a standstill. A person skilled will understand that this feature protects the transmission against damage.

In the preferred embodiment the park brake is automatically released whenever the gear lever 226 is moved out off its neutral position by allowing air flow to the park brake outlet.

The gearshift 210 further includes a starter valve 246 mounted to the body 212 and in fluid communication with the engine starter motor. In the illustrated embodiment the starter valve 246 is manually operated and the driver must activate it in order to start the vehicle's engine. As a safety precaution the starter valve 246 is prevented from being activated while the gearlever 226 is in any position other than neutral. This is achieved by mounting a cam 248 on the shaft 228 in such a manner that it rotates with the gear lever between a receiving position wherein the starter valve may be activated and an obstructing position wherein the starter valve is obstructed from being activated. As shown in Figure 9 the cam 248 has a recess 250 which is oriented to receive a portion 252 of the starter valve 246 when the cam is in its receiving position i.e. when the gear lever is in its neutral position. It should be clear that when the gear lever 226 is moved into any position other than neutral, the cam will automatically move into its obstructing position wherein the recess 250 is not aligned with the starter valve portion 252 and, as a result, the starter valve cannot be activated.

The gearshift 210 also includes a reverse switch 254 which has a runner 256 following the cam 248. The reverse switch 254 may be used to activate an indicator for indicating to people in the vicinity of the vehicle that the vehicle is reversing.

The layout of the valves 216 and in particular the valve outlets 220 and 222 in combination with the activating formations on the selector 234 are designed so that the reverse solenoid cannot be activated without the gearshift 210 first having been put into neutral. In other words, the gear lever 226 cannot be moved into its reverse position without first having been moved into its neutral position wherein the park brake is automatically activated.

The gearshift 210 will generally be run off the vehicle's existing air supply.

Returning now to the description of the vehicle 10, It must further be understood that the transmission could be hydrostatically driven so that an inline drive train is no longer necessary seeing that the vehicle could be driven by direct drive motors located at the vehicle's wheels. The advantage of this is that the vehicle's engine could be positioned to free up space for the cabin 40 in the chassis 20, thereby giving additional options on the position and orientation of the cabin.

The hauler 10 may further include a fail-safe brake system as described in the specification of the applicant's co-pending international patent application PCT/IB2011/054530 entitled "Fail-Safe Brake System". Again, the fail-safe brake system will now be described for ease of reference.

Figure 10 shows a diagrammatic representation of a fail-brake system 310 for use in combination with an existing service brake system of the vehicle. It must be understood that the vehicle (10) includes a service brake system, a park brake system and a fail-safe brake system (310). Although used in combination the fail-safe brake system 310 may be activated and deactivated entirely independently from the service brake and park brake systems of the vehicle.

The system 310 includes a high pressure fluid source 312 for supplying fluid to a number of independent circuits which in use feed braking means 314 for braking the vehicle. In the illustrated embodiment the braking means 314 is in the form of disc brake assemblies provided at each end of the vehicle's front and rear axles. From Figure 10 it can be seen that the vehicle has four wheels with disc brakes 314.1 and 314.2 located at the ends of the front axle and disc brakes 314.3 and 314.4 located at the ends of the rear axle of the vehicle. Each disc brake assembly 314 is fitted to an existing trumpet housing assembly located at each end of the axles. Figure 11 shows a perspective view of the disk brake assembly 314 fitted to the trumpet housing assembly. In this figure it can be seen that the disc brake assembly includes a brake disc 316 and a booster 318 which in use assists in applying a braking force on a calliper 320. A person skilled in the art of brake systems will be familiar with the functioning of a disc brake assembly and it will accordingly not be discussed in detail.

Returning to Figure 10, it can be seen that the high pressure fluid source 312, which in the preferred embodiment is an air compressor run from the vehicle's engine, feeds a release valve 322 though line 324. In the system 310 the release valve 322 controls the maximum pressure in line 324 and, as a result, the system. The release valve 322 will in use exhaust to the atmosphere or charge the system depending on the pressure in the system. From the release valve 322 air is supplied to a protection valve 26. It is at the protection valve where line 324 splits into four independent air flow circuits which are fed through lines 328, 330, 332 and 334 respectively. Apart from regulating the air flow between the different circuits the protection valve 326 also protects the different circuits so that each of the circuits stays separate without any flow of air occurring between them.

As mentioned above the system 310 includes four independent circuits. The first circuit, which is associated with line 328, is a primary circuit which in use brakes the rear axle. The second circuit, which is associated with line 330, is a secondary circuit which in use brakes the front axle while the third circuit, which is associated with line 332, is a trailer circuit which in use brakes the trailer axle if a trailer is connected to the fail-safe brake system 310. The fourth circuit, which is associated with line 334, is an auxiliary or control circuit which includes a number of control valves which are generally indicated by the reference numeral 338 and discussed in detail below. Returning to the primary, secondary and trailer circuits it can be seen from Figure 10 that these circuits include reservoirs 336.1 , 336.2 and 336.3 respectively. Air is allowed to accumulate in the reservoirs for use at the disc brakes 314 or trailer brakes (not shown).

The control valves 338 are used to ensure that the vehicle 10 is only fully operable while the fail-safe brake system 310 is completely deactivated. In the illustrated embodiment the control valves 338 include a gear shift control 340, an accelerator air throttle valve 342 and a valve 344 which only allows air to pass through it once it has been activated. In the illustrated embodiment the control valves 338 are manually operable to ensure that the driver of the vehicle has to deactivate the fail-safe system by following a safety procedure. The valve 344 is for example a push button valve which only allows the flow of air towards the gear shift control 340 and accelerator valve 342 once the button has been pressed. Therefore, the valve 344 is positioned first in the air flow line 334 of the auxiliary circuit so that air is prevented from flowing to either the gear shift control 340 or accelerator valve 342 before activation of the valve 344. It should be clear that the gear shift control 340 only allows the vehicle's gearbox to shift gears when a required air pressure is present in its feeding line 340.1. In turn, the accelerator valve 342 controls the air flow in line 334 towards a booster 346 located on the vehicle's fuel pump (not shown). This is done in order to control the engine's revolutions and accordingly the speed at which the vehicle is travelling. If the air pressure in line 334 is inadequate as a result of for example an air supply shutdown, the accelerator valve 342 stops operation of the engine.

The push button valve 344 can furthermore only be activated while the pressure in line 334 is at a required minimum pressure. In other words, air supply to the system is cut off below the required minimum pressure. In the preferred embodiment the minimum pressure is preferably between about 3 and 6 bar, more preferably between 4 and 5 bar and most preferably about 4.7 bar. Should the air pressure drop to below the required minimum pressure, i.e. 4.7 bar, at any time the valve 344 will automatically shut down. This will result in the accelerator valve 342 preventing air flow to the booster 348 in order to stop operation so that the engine is allowed to idle only, the gear shift control shifting the gearbox to neutral and emergency brakes (not shown) being activated so that the vehicle is brought to a standstill. Once the emergency brakes have been activated, the vehicle cannot be moved without first deactivating the fail-safe brake system again.

The fail-safe brake system 310 also includes brake pedal valve 348, associated with the vehicle's brake pedal, and a hand brake valve 350, associated with the vehicle's hand brake, for controlling air flow in the primary, secondary and trailer circuits. As shown in Figure 10 the brake pedal valve 348 is located so that both the primary and secondary circuits pass through it, thereby ensuring that operation of the brake pedal valve controls activation of the disc brakes 314 on both the front and rear axles. In the primary circuit, air is allowed to flow from line 328 towards the brake pedal valve 348 via line 352. While no pressure is applied to the brake pedal of the vehicle air is prevented from passing though the valve 348 and deactivating the disc brakes 314.3 and 314.4. As soon as pressure is applied to the brake pedal, the brake pedal valve 348 is activated and air is allowed to flow through the valve towards a rear axle valve 356 which in turn controls air flow to the rear disc brakes 314.3 and 314.4 through lines 358 and 360 respectively. The rear valve 356 is also fed by line 328 connecting the reservoir 36.1 to the rear valve directly. Similarly to the rear brakes 314.3 and 314.4, the front brakes 314.1 and 314.2 are also connected to the brake pedal valve 348 so that activation of the brake pedal valve in use allows air to flow to the front brakes via lines 362 and 364. Therefore, pressure has to be applied to the brake pedal in order for the air flow to reach the front and rear brakes via brake pedal valve 348. This means that the fail-safe brake system 310 cannot be deactivated without the operator applying pressure on the brake pedal of the vehicle.

A further safety feature of the fail-safe brake system 310 is that air supply to the front and rear disc brakes 314 are also controlled by the hand brake valve 350. From Figure 10 it can be seen that the hand brake valve 350 is fed by line 366 which is connected to line 334 at a location downward of the push button valve 344. As a result, air flow only reaches the hand brake valve 350 after activation of the push button valve 344. In its closed position, i.e. when the vehicle's hand brake is activated, air is prevented from passing through the hand brake valve 350 and into the auxiliary and trailer circuits. This prevents air from reaching the front brakes 314.1 and 314.2 and rear brakes 314.3 and 314.4 via lines 368 and 370 respectively. When the hand brake valve 350 is in its open position, i.e. the vehicle's hand brake is deactivated, air is allowed to flow to the front, rear and trailer brakes to deactivate them.

The hand brake valve 350 further controls air flow to a spring brake actuator (not shown) which in turn controls the emergency brakes of the vehicle. Should the air supply to the spring brake actuator be shut off by activation of the hand brake valve 350, the emergency brakes will automatically be applied. A skilled person will be well aware that when applying emergency brakes on a heavy duty vehicle, the brakes must be applied gradually in order to prevent serious damage to the vehicle. As a result, whenever the emergency brakes are applied they are applied gradually, thereby preventing catastrophic failure.

Turning now to the trailer circuit, it can be seen from Figure 10 that the line 332 supplies air to a trailer control valve 372 which controls air supply to trailer brakes (not shown) via couplings 374. The trailer control valve 372 is connected to the brake pedal valve 348 via lines 376 and 378 and to the hand brake valve 350 via line 380. As a result the trailer circuit is directly linked to the primary, secondary and auxiliary circuits so that air supply to the trailer control valve 372 may be controlled by the brake pedal valve 348 and hand brake valve 350. In other words, the trailer brakes can only be deactivated once the front and rear brakes 314 of the vehicle as well as the vehicle's hand brake have been deactivated. The trailer control valve 372 further controls emergency brakes on the trailer in that as soon as the air supply to the trailer fails, a spring brake actuator (not shown) automatically applies the emergency brakes on the trailer. Similarly to the vehicle's emergency brakes, the trailer's emergency brakes are applied gradually to prevent catastrophic failure. T/IB2011/055575

-20-

The method of deactivating the fail-safe brake system 310 will now be described in greater detail. In order for a driver to operate the vehicle there are a number of procedural steps that need to be followed. Once the vehicle has been started, air pressure will build up in line 334. When the pressure reaches the required minimum pressure of 4.7 bar, the push button valve 344 in line 334 can be activated to allow air supply to the gear control 340, accelerator valve 342 and hand brake valve 350. To deactivate the fail-safe brake system 310 the hand brake valve 350 must be activated by releasing the vehicle's hand brake. Accordingly it should be clear that the fail-safe system 310 can only be deactivated once both the brake pedal valve 348 and hand brake valve 350 are charged i.e. at the required working pressure. With both valves 348 and 350 charged the vehicle's gearbox can be put into gear. Up to this stage the gearbox is in neutral, thus preventing any torque from being transmitted to the vehicle's wheels. Only after the above procedure has been followed can the vehicle be driven by applying a force on the accelerator pedal.

Although the fail-safe brake system 310 has been described above as a pneumatic system, it should be clear that a fluid other than air could be used without departing from the principles of the invention. It should further be clear that although the system 310 has been described as a fail-safe brake system, it could also be used merely as an auxiliary system on a vehicle.

In the preferred embodiment of the vehicle 10 both the gearshift 210 and the failsafe brake system 310 are pneumatically operable. By being pneumatically operable the interface of the lines feeding the controls between the cabin 40 and the chassis is pneumatic. It must be clear that the pneumatic interface allows for easy detaching of the cabin from the chassis. Instead of having to disconnect different types of connections, such as pneumatic, hydraulic and electrical connections for example, the cabin may be detached by simple disconnection the pneumatic interface. Another advantage of using pneumatic systems in the hauler 10 is that the operating controls for operating the hauler may be located anywhere in the cabin 40. This allows for the internal layout of the cabin to be more economically designed. Yet another advantage of converting the systems to pneumatic systems is that the number of openings in the cabin 40 is reduced significantly, thereby reducing the amount of external noise entering the cabin and accordingly improving the sound proofing of the cabin. In view of the fact that the number of openings in the cabin has been reduced, the ventilation in the cabin may also be improved. It is envisaged that an air conditioning system may be used to provide fresh air in the cabin while the temperature inside the cabin is also reduced.

It is further envisaged that the hauler 10 may include a hydraulic power take off (PTO) which is independently driven. The PTO further has a relief valve which protects the unit from catastrophic failure.

Figure 5 shows a second embodiment of the vehicle 10 according to the invention. In this embodiment the vehicle is in the form of a grader 60. Although the grader 60 is functionally different from the hauler 10, the features described above with reference to the hauler may be incorporated into the grader. Therefore, the reference numerals used above with reference to the hauler are used to denote the same features of the grader.

Similar to the hauler 10 as described above, the grader 60 has a modular chassis 20 which includes an additional support section 62 as shown in Figure 5. The support section 62 is located behind a rear axle 64 and carries addition equipment such as a towage 66. In use, the support section 62 is attached to the chassis 20 by means of connecting formations 68 located on the chassis. The connecting formations 68 are in the form of connecting plates which are welded to the chassis 20. The support section is then bolted to the connecting plates.

It will be understood that an advantage of the modular design of the chassis 20 is that it allows for easy splitting of the unit. Similarly to the way in which the front section 22 may be removed from the rear section 24, the support section 62 may be removed from the rear section 24 by removing the bolts at connections 68. An advantage of the modular design is that it reduces maintenance and service times. For example, by simply removing the support section 62 from the rear section 24, direct access is obtained to the rear axle 64.

It is further envisaged that the rear axle of the grader 60 may be steerable. When incorporating a steerable rear axle in combination with a steerable front axle it is envisaged that the turning angle of the front axle be either more acute than that of the rear axle or that the front axle is prioritised to turn earlier than the rear axle so that the rear end of the vehicle will break out later in order to prevent steering into obstacles.

In yet another embodiment the vehicle may be in the form of a container handling device 70 as shown in Figure 7. The container handling device 70 may include a scissors-type container handling apparatus. This may generally be of the type marketed under the name Power X and as described in the specification of ZA68/6 39.

The vehicle 70 includes a self-propelled horse 72 having steerable wheels 74. The horse 72 includes a motor, for example a diesel motor, which drives the wheels 74 either mechanically or hydraulically through suitable hydraulic motors. At least where hydraulic motors are used, the wheels 74 will typically be driven independently of one another.

The horse 72 includes an enclosed cab 40 for an operator/driver and possibly at least one other person mounted on the chassis 20. As indicated above, the cab may be air-conditioned and may include various safety features such as seat belts for the personnel accommodated therein, a roller-over protection structure and/or a fall-on protection structure for the personnel. 2011/055575

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As mentioned above the vehicle 70 of the invention also includes a scissors-type container handling apparatus indicated generally by the numeral 76. In this embodiment of the vehicle, the cabin 40 is mounted on the front section of the chassis while the rear section is in the form of the container handling apparatus. As in the conventional scissors-type container handling apparatus 76 includes inner and outer U-shaped frames 78 and 80 respectively. Each frame has longitudinally extending side frame members 82, 84 connected to one another by a transversely extending frame member (not visible in the drawing) at their forward ends. The container handling apparatus 76 also has two support members (not shown) which are pivotally connected to the transverse member of the outer frame. The support members are moveable between a first, movement allowing position wherein the transverse member of the inner frame 78 is allowed to move freely past the support members and a second, movement obstructing position wherein the transverse member is obstructed from moving past the support members. In its second position the free ends of the support members are positioned to engage the transverse member of the inner frame 78, thereby supporting the inner frame when carrying a container.

The transversely extending forward frame member of the outer frame 80 is connected to the rear of the horse 72 at a coupling indicated diagrammatically by the numeral 86. It is envisaged that in this embodiment the horse and container handling apparatus may be connected permanently.

The coupling 86 allows for articulation of the apparatus 76 relative to the horse 72 about a pitch axis, i.e. an axis which is transverse to the longitudinal direction of travel 90. The coupling 86 may also allow for at least a limited degree of articulation of the apparatus 76 relative to the horse 72 about a yaw axis, i.e. a vertical axis. The coupling may also allow for articulation of the apparatus 76 relative to the horse about a roll axis, i.e. the longitudinal, fore-and aft axis. 5575

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The scissors-type container handling apparatus 76 has wheels 88 carried by the inner frame 78 of the apparatus. These wheels may be designed to be free wheels i.e. not propelled. Alternatively they may be driven by independent hydraulic drive motors (not shown) powered by the motor of the horse 72.

The numeral 100 in the drawing indicates a container which is, in this case, an open-topped container or bin which has a pivoted rear door 102. A front wall 104 of the container carries conventional brackets 106 which are shaped to rest on the transverse frame member of the inner frame 78 when the container handling apparatus 72 is reversed into position such that the side frame members 82 of the inner frame extend longitudinally alongside the side walls 108 of the container and the conventional double-acting hydraulic piston and cylinder assemblies 90 of the apparatus 76 are extended slightly. In accordance with the invention, the container and/or the apparatus 76 also includes container locks (not shown) which are operative to lock the brackets releasably to the transverse frame member of the inner frame in such a manner as to prevent the brackets from lifting off the transverse frame member. It is envisaged that the container locks could be in the form of a securing mechanism as described in South African patent application 2011/08299 entitled "Securing Mechanism".

The securing mechanism and the method of securing the container 100 to the container handling apparatus 76 will now be described briefly for ease of reference.

The securing mechanism includes means for manipulating the support members of the apparatus 76 between its movement allowing and movement obstructing positions. The manipulating means is in the form of a double acting hydraulic piston and cylinder assembly which is connected to the transverse member of the outer frame 80 at one end and one of the support members at the other end. The piston and cylinder assembly is hydraulically operable to move the support members between their first and second positions. The securing mechanism further includes container locks to lock the container 100 down on to the container handling apparatus 76. In the illustrated embodiment the container locks are located on the transverse member of the inner frame 78 and operable to lock the brackets releasably to the transverse member in such a manner as to prevent the brackets from lifting off the transverse member.

The numeral 110 indicates a conventional channel extending longitudinally on a side wall 108 of the container 100. It will be understood that a similar channel is provided on the opposite side wall. In use, rollers 92 at the rear ends of the side frame members 84 of the outer frame locate beneath the channels 110 when the container 100 is lifted off the ground by extension of the cylinder assemblies 92, such that the channels 110 rest on the rollers. In accordance with the invention, the side walls of the container also carry locking rails 1 2 over which the rollers move when the vehicle 70 is reversed into position to lift the container. After the container has been lifted, the locking rails, being located on the side of the container, prevent the rear end of the container from lifting off the apparatus 76 during transportation. The front of the container 100 is secured by means of the container locks which are operated from inside the cabin 40.

The container locks and locking rails described above effectively lock the container down relative to the apparatus 76, and enable the vehicle 70 to be driven at fairly substantial speeds, for example 60km/h, without any danger of the container lifting off the container handling apparatus 76.

It is further envisaged that the vehicle 70 may include a suspension to improve the ride comfort at high speeds.

Although an example of the invention has been described with reference to a container in the form of an open-topped bin, it will be understood that the apparatus 76 is intended for multi-bin application and that many other different types of containers for different purposes may be handled and, in appropriate cases, tipped by the apparatus 76.

The overall length of the vehicle 70, including both the horse 72 and apparatus 76, is preferably 8m or less, most preferably 7m or less. A vehicle of this length is advantageous both from the point of view of manoeuvrability and from the point of view of ease of movement of the vehicle from one level in a mine to another level. However, it should be understood that the length of the vehicle 80 could be longer than described above for the haulage of higher payloads.

It should be understood that although the vehicle 10 has been described with reference to three particular embodiments where it is used as a hauler, grader and container handling vehicle, the features of the vehicle described above could be incorporated in a wide range of embodiments for use in different applications. It should further be understood that the vehicle according to the invention is not limited to be used underground but may also be used in applications above ground.

Claims

CLAI S

1. A self-propelled vehicle for use in the mining, industrial and/or agricultural industry, the vehicle including:

a cabin comprising a roll-over protection structure and a fall-on protection structure, the cabin having a seating arrangement suitable for accommodating the driver;

wherein the cabin is detachably connectable to the chassis and replaceable as a single unit.

2. A vehicle according to claim 1 , including a gearshift for selecting different gear ratios in the vehicle's transmission and a fail-safe brake system, the gearshift and fail-safe brake system being either pneumatic or hydraulic, thereby allowing the interface between the gearshift and operating controls of the fail-safe brake system in the cabin and a high pressure fluid source on the chassis to be either pneumatic or hydraulic in order to reduce the number of connections in the interface between the cabin and chassis so that the cabin may be easily detached from the chassis as a single unit.

3. A vehicle according to claim 2, wherein the gearshift and fail-safe brake system are both pneumatic so that the interface between the high pressure air source on the chassis and the gearshift and controls of the fail-safe brake system on the cabin is purely pneumatic.

4. A vehicle according to any one of claims 1 to 3, wherein the forward and rear sections of the chassis are detachably connectable to each another so that the chassis may be taken apart by disconnecting the complementary connecting means.

5. A vehicle according to any one of claims 1 to 4, wherein the chassis comprises three sections, namely front and rear sections which are detachably connectable to one another to form a major part of the chassis and a support section which is detachably connectable to the rear section.

6. A vehicle according to claim 5, wherein the rear axle of the vehicle is located on the rear section of the chassis in a position wherein direct access thereto is gained by removing the support section.

7. A vehicle according to any one of claims 1 to 6, wherein the chassis defines a space wherein a portion of the cabin is received when connected to the chassis so that the cabin is at least partially sunken into the space defined by the chassis in order to lower the seating position of the driver.

8. A vehicle according to claim 7, wherein the chassis has two main beams running along the length of the chassis, the beams defining the cabin receiving space between them.

9. A vehicle according to claim 8, wherein both beams are split into front and rear portions which form part of the front and rear sections of the chassis respectively, wherein the connecting means are located at the ends of the front and rear portions of the beams that face each other when the chassis is assembled.

10. A vehicle according to any one of claims 1 to 9, wherein the cabin has an internal module defining the seating arrangement, the internal module being replaceable as a unit so that it may be replaced by another internal module when the cabin is detached from the chassis.

11. A vehicle according to any one of claims 1 to 10, wherein the cabin has a frame including a number of legs which are connected to a top section which, in use, caries a roof, the legs being detachably connectable to the chassis.

12. A vehicle according to claim 11 , wherein the legs of the frame are connectable to the chassis by means of bolts.

13. A vehicle according to any one of claims 1 to 12, including a fail-safe brake system for use in combination with a service brake system of the vehicle, the fail-safe brake system comprising:

a high pressure fluid source for supplying fluid to the fail-safe brake system;

a protection valve splitting a feed line running from the high pressure source into at least two independent fluid flow, circuits, one being a primary circuit including braking means for braking the vehicle when the fail-safe brake system is activated and the other being an auxiliary circuit for controlling fluid flow to the primary circuit; and

14. A vehicle according to claim 12, wherein the fail-safe brake system is pneumatic.

15. A vehicle according to any one of claims 1 to 14, including a gearshift for a transmission of the vehicle, the gearshift comprising a body, a valve bank having a number of outlets which, in use, are in fluid communication with actuators on the transmission responsible for selecting different transmission ratios, and a selector for controlling the flow of fluid to different valve outlets, the selector being movable between a number of positions which allow different fluid flow paths through the valve bank in order to activate and deactivate different actuators depending on the valve outlets to which fluid is supplied, thereby engaging and disengaging different gear ratios in the transmission.

16. A vehicle according to claim 14, wherein the gearshift is pneumatic.

17. A vehicle according to any one of claims 1 to 16, wherein the vehicle is a hauler, grader or container-handling vehicle.