Elevator – industrial lift truck – or stationary lift for vehicle – Inclined elevator
Reexamination Certificate
2000-01-21
2002-10-08
Ellis, Christopher P. (Department: 3651)
Elevator, industrial lift truck, or stationary lift for vehicle
Inclined elevator
C187S246000, C187S254000, C414S595000
Reexamination Certificate
active
06460657
ABSTRACT:
FIELD OF THE INVENTION
Our present invention relates to a conveyor apparatus for open-cut mining and especially for removal of the overburden and mine deposits in the formation of stopes in a step-like manner with progressively increasing widening of the excavation with increasing excavation depth.
BACKGROUND OF THE INVENTION
In open-cut mining the overburden and mine deposits are removed in a step-like formation, i.e. with the formation of stopes. The depth of the excavation continuously increases and with increasing depth, there is an increased widening of the funnel-shaped opening of the excavation. The excavator is usually moved along a bottom of the excavation to form a stope and, depending upon the stability of the ground, the equipment used and economic conditions, the stope height can average around 15 m and for the removal of the loose material, the inclined planes between the stopes serve as roads along which the excavated material is removed. The deeper the deposit being mined, the wider must be the opening of the cut by a factor of 400 to 600, thereby defining the funnel shape of the excavation. Material loosened by drilling or explosives (hard rock and solid ores) as well as the overburden are transported away as a rule in trucks formed as trough tippers, mine cars and the like. These trucks travel from the stopes to the grade surface or ground level along the road. The serpentine path increases with mining depth and the travel can be at a speed of about 10 Km/h upwardly and about 35 Km/h downwardly. This requires high concentration of the part of the vehicle drivers and always creates the possibility of accidents.
OBJECTS OF THE INVENTION
It is the principal object of the present invention to provide a conveyor apparatus which can carry out mined material including the mined deposit and the overburden from locations in an open-cut mining operation to the surface in a more economical and reliable manner without significant cost.
Another object of the invention is to provide an apparatus for this purpose which allows adjustment to increasing mining depths.
It is also an object of this invention to provide a conveyor apparatus for open-cut mining in a funnel-shaped excavation with removal of overburdened mined deposits, formations of stopes and increased width at an opening of the funnel-shaped excavation at grade level with increased excavation depth, whereby the drawbacks of earlier excavation techniques are avoided, long transport distances are eliminated and the danger of accidents is minimized.
Still another object of this invention is to provide an improved apparatus which obviates the drawbacks of earlier excavation systems.
SUMMARY OF THE INVENTION
The objects are attained, in accordance with the invention in a conveyor apparatus for the purposes described and which can be advanced downwardly for increasing depth of excavation. The conveyor apparatus of the invention comprises:
an inclined elevator extending from an edge of the opening at grade level to the floor level;
a traveling platform riding on the inclined elevator and adapted to receive a truck to be filled with overburden or mined deposits;
at least one cable passing over separate upper and lower cable pulleys and having an upper pass of the cable extending to the upper cable pulley from the traveling platform and a lower pass of the cable extending from the lower cable pulley along the elevator;
a counterweight riding on the elevator and connected to the lower pass of the cable; and
a conveyor mechanism operating at grade level at an upper end of the elevator and having a cable drum looped by a portion of the cable between the upper and lower cable pulleys.
According to the invention, therefore, an elevator along which trucks for receiving the mined material can be guided is provided to extend from an edge of the opening of the funnel-shaped excavation at grade level to a floor level at which excavation is carried out and preferably to the bottom of the cut. At least one cable is provided which has upper and lower passes extending over respective cable pulleys with the upper pass of the cable being affixed to a platform on which the car, usually a trough tripper or dumpable car can be carried while the lower pass of the cable is affixed to a counterweight. Both the platform and the upper weight are being guided along the inclined conveyor.
At grade level the cable passes around a conveyor mechanism or machine. The mined material carried by the car or truck is thus transported along the elevator in an upward direction to the edge of the cut.
Because of the inclination of the conveyor which can correspond to the inclination of the funnel-shaped excavation, e.g. even with increasing mining depth, and by elimination of the serpentine path which the cars or truck had to travel previously from the bottom of the excavation to the top thereof, the distance which the trucks travel is minimized thereby simplifying the operations and minimizing the burden placed on the trucks or cars.
A loaded truck or car at the bottom of the excavation need only be placed on the platform in its lowered position, secured in place with appropriate arresting means and then transported driverlessly to the surface at which point another driver can take over control and transport of the car or truck. The result is a highly flexible, economical usage of personnel since different individuals can be provided at the surface and at the floor of the excavation for transport purposes.
Since the counterweight moves in a direction opposite the platform and balances the comparatively high weight of the platform and the loaded car, which may amount to about 500 metric tons, the net mass which must be displaced by the input of energy can be only a fraction of the sum of the load carried by the truck or car, the weight of the truck or car itself, the weight of the platform and the weight of the cable paths connected thereto. The conveyor mechanism thus need only supply a fraction of the energy which would otherwise be necessary to move this latter total mass. It is possible to operate in a single track system with the workload operating in its track and the counterweight in its track.
According to a feature of the invention, the conveyor mechanism driving the cable has a rerouting drum looped by the or each cable and between the upper and lower passes of the or each cable or has individual pulleys or wheels for each cable, the cable returning after being looped around this drum or the rerouting pulleys. The conveyor mechanism or drive may be of the Koepe type.
Preferably the rerouting drum is connected with the conveyor mechanism with a variable spacing therebetween, the system including a cable magazine containing a supply of cable for lengthening of the travel of the cable. With increasing depth of excavation and thus with increasing travel distance, the cable must be effectively lengthened so that there is a progressive increase in the cable weight as well.
For deeper excavations and thus the need to displace the platform to increasingly greater depths, it is merely necessary to release the rerouting drum anchored to the foundation and move it to a new position closer to the drum of the drive mechanism. The movable drum is then fixed at this new position. The rerouting drum can have a diameter of, for example, 9 m and can have journal blocks which are shiftable linearly on respective tracks. The force required for the shifting can be developed hydraulically and when a number of cables are provided for the elevator, a corresponding number of rerouting pulleys can be used instead of a single rerouting drum. For increased output of the mine, a multiplicity of such inclined elevators can be provided in the funnel-shaped excavation in spaced apart relationship therein.
According to a preferred embodiment of the invention, the rerouting drum or assembly of pulleys or rerouting roller can be inclined to the horizontal and each cable can pass around the cable drum of the drive mechanism with double looping so that each cable has at least two turn
Isenburg Werner
Lütticke Paul-Gerhard
Rollmann Folker
Schröder Walter
Schubert Wolfgang
Dubno Herbert
Ellis Christopher P.
Sharma Rashmi
Siemag Transplan GmbH
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