Classifying – separating – and assorting solids – Sifting – Elements
Reexamination Certificate
1999-01-04
2001-02-13
Nguyen, Tuan N. (Department: 3653)
Classifying, separating, and assorting solids
Sifting
Elements
C209S241000, C209S244000
Reexamination Certificate
active
06186338
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a self-propelled material-processing apparatus.
2. Present State of the Art
It is known to provide self-propelled screening apparatus of the general type which comprise a chassis, a prime mover mounted on the chassis, moving means supporting the chassis and arranged to be power-operated by the prime mover in order to move the apparatus over the ground, a hopper arranged to receive a supply of bulk material to be screened by the apparatus, a conveyor arranged to receive material from the hopper and to convey such material to a discharge end of the conveyor, a screen arranged to receive material from the discharge end of the conveyor, and one or more discharge conveyors arranged to receive screened material from the screen and to discharge such material to a required deposition zone or zones, spaced outwardly of the chassis of the apparatus.
A self-propelled screening apparatus of the above general type may be used (a) to carry out screening operations on the move when it is required to form travelling deposits of screened material e.g. to fill-in a pipeline trench after laying of a pipeline, or to introduce hardcore or other foundation material to form the base of a road, or (b) to carry out static screening operations when required, but being capable of being moved from one position to another on a particular site when required.
A typical screening apparatus is of substantial overall length (when the component parts are deployed to screening and discharge positions), in that usually a hopper is arranged at one end of the chassis, a conveyor elevator extends lengthwise of the apparatus from the hopper to a discharge end above, or located outwardly of the opposite end of the chassis; and after material falls under gravity to the screen e.g. to a “screen box”, and one (or more) discharge conveyor (which is arranged to receive screened material from the screen box) extends outwardly away from the chassis in order to deposit the screened material at a required deposition zone.
Discharge conveyors which may be used include so-called “tail conveyors”, which discharge screened material rearwardly of the apparatus, and “side conveyors” which discharge the screened material laterally of the apparatus. Different discharge conveyors may be used to receive different screened “fractions” from the screen box, and to discharge such material to require deposition zones. A typical screening apparatus might have a single tail conveyor, and a pair of side conveyors, so that three different screened fractions or portions can be separated in the screen box, and discharged to separate discharge locations.
It is desirable for the apparatus to be easily manoeuvrable (in order to move from one static screening location to another, or to carry out screening operations “on the move”), and use of endless crawler tracks is therefore particularly suitable to form the moving means to propel, and to steer the apparatus. However, the length of a practical arrangement of endless tracks (to give required easy manoeuvrability) is much less than the overall length of the apparatus (when its component parts are deployed to screening/discharge positions), and in which they project outwardly of the chassis to substantial extents. This results in substantial inertial loads being generated when the apparatus is moving, and particularly when the apparatus is being steered. (This is somewhat similar to the inertial loads generated when an individual carries a horizontal ladder from a mid position and tries to rotate). It is therefore important to try, as far as possible, to maintain the overall centre of gravity of the apparatus (and its component parts) substantially centrally of the endless tracks, when in the deployed position.
In addition, endless track types of apparatus normally require to be transported on a “low loader”, in order to move over the public highway from one site to another, and usually the component parts (and especially those which project from the chassis in the deployed position) must either be de-mounted, or else be moved to transport positions in which they at least reduce the extent of their projection from the chassis, before the apparatus can be transported on the low loader.
However, while the inertial loads of the deployed apparatus will be reduced, the much greater road speed of the low loader (compared with the self-propelled movement of a tracked apparatus in operation) means that any substantial mass of the apparatus (which is off-set from the centre of gravity of the apparatus) will apply substantial inertial load when the low loader goes around a bend of a road, or negotiates a roundabout.
This means that the apparatus must be very securely restrained when it is carried on a low loader, but even with such restraint, very substantial inertial loads generated when going round a bend in a road could still be very hazardous to other traffic, or may even result in the low loader being overturned e.g. if the low loader is towed around a roundabout at excessive speed.
OBJECTS AND BRIEF SUMMARY OF THE INVENTION
The present invention therefore has been developed primarily with a view to provide a self-propelled material-processing apparatus which is well balanced when the component parts are deployed to operative positions, but in which improved stowage of the component parts can be obtained (when these parts are adjusted to transport positions), in the sense that the component parts are located within, or closely adjacent to the external “envelope” of the apparatus as determined by the chassis on which the component parts are mounted.
By this means, reduction of inertial loads can be achieved, thereby contributing to a more stable (and therefore less hazardous) travelling condition, and also to provide an overall reduced cubic capacity.
According to one aspect of the invention there is provided a self-propelled material-processing apparatus.
Preferably, the discharge conveyor comprises a tail conveyor, and which has foldable portions which can be constrained to move between “in line” positions in which one portion extends beyond the other, to form the operative discharge position, and a folded position, in which one of the portions underlies the screen, and the other portion extends generally upwardly.
In order to give a balanced apparatus, when deployed to the operative screening/discharge mode, the chassis may project forwardly and rearwardly of the endless tracks, and in particular the hopper may be mounted on an outrigger arrangement, to project forwardly of the endless tracks, whereas the discharge conveyor, (when it takes the form of a tail conveyor), projects in an opposite direction from the opposite end of the chassis when in the deployed position. This provides reasonable balance to the apparatus, but in order to locate the overall centre of gravity of the apparatus substantially centrally of the endless tracks, which is preferred, the prime mover e.g. a heavy duty diesel engine, may be mounted on the chassis forwardly of the centre of gravity, so as to assist in counter balancing the load of the tail conveyor, and also of the processing device, when in their deployed positions.
The material processing device may comprise: a screen; a crusher; or a combination of a crusher and a screen.
The screen may take the form of a so-called screen box, and preferably pivotally mounted on an upstanding support structure mounted at the rear end (opposite to the hopper end) of the chassis. The screen box may be carried by a pair of A-frames, mounted one on each side, and with the apex of each A-frame being pivotally mounted on the upstanding structure. Pivotal adjustment of the screen box therefore allows the screening angle of the deck or decks of the screen to be adjusted, to suit different types of material.
Preferably, the supply conveyor is pivotally connected to the screen box, at or near to its discharge end, so that the conveyor can also adjust its position automatically, with any adjustment in screening angl
Nguyen Tuan N.
Workman & Nydegger & Seeley
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