US Patent 5031752 - Curvable chain scraper conveyor

Источник: Source: Patent Storm : U.S. Patents

ABSTRACT

Description of the invention

BACKGROUND OF THE INVENTION Curve conveyors constructed as chain scraper conveyors, capable of shifting in their longitudinal direction e.g. by being towed by a winning machine situated at the head and equipped with crawler tracks, are known in various constructional forms (DE-OS 37 27 272, DE-PS 32 41 129, DE-OS 33 39 404). Such self-moving curve conveyors are used e.g. in room and pillar retreating working or under similar conditions. In curve chain scraper conveyors, the actual conveying line consists of a plurality of short conveyor segments (providing conveyor channel lengths or run sections) which are connected, leaving clearance adequate for curve formation, by means of screw bolts or other connecting elements in a tension-resistant but articulated manner. The length of the conveyor segments and the amount of axial freedom at the connection zones determine the curvability of the conveyor, i.e. the smallest possible curve radius of the conveyor. When travelling along a curved course, the channel joints open at the outer side of the curve. This involves increasing the central length of the conveyor line. This change in length must be permitted by the scraper chain, which for this reason is adjustable in its effective length and tension by means of a loading device. If the loading device used is e.g a hydraulic cylinder device associated with a turn-round drum for the scraper chain, this device must be constructed so that the cylinders can manage the excess pressure when curves are formed and the conveyor line is correspondingly altered in length. Moreover the conveyor segment butt ends are pressed against one another by the preloading of the scraper chain, at both sides when the course of the conveyor is straight, but only at the inner side of the curve in curved regions. The greater the preloading of the scraper chain, the greater the forces and restoring moments tending to return the conveying line to a straight course again. When the conveyor is moved bodily in the longitudinal direction e.g. by crawler track running gear at its head end, or by a winch or the like, the entrainment of the conveying line is effected on the one hand by the friction of the conveyed material in the conveyor run and on the other hand in the form of thrust via the scraper chain band circulating about the return point or turn-round point at the rear machine frame. This means that when the curve conveyor is displaced during conveying work the scraper chain is additionally loaded by the high towing forces. These forces are also transmitted via any chain preloading device, so that the device has to be made substantially stronger. In the stationary state of the conveyor the preloading cylinder has then to be switched back to a lower pressure level, to avoid high wear caused by conveying with excessively strongly preloaded scraper chains. SUMMARY OF THE INVENTION The object of the present invention is to construct a curvable conveyor of the type specified, intended preferably for mining use, in which when displacement of the conveyor occurs the scraper chain and any tensioning device thereof are relieved of these excessively variable forces and the conveyor is better stabilised in whatever course it takes, i.e. restoring forces resulting from the loading of the scraper chain are of lesser effect. According to the invention, this is achieved by providing a tension element which extends along the length of the conveying line, is coupled inn force-transmitting manner to the two end regions of the conveyor, and which is so constructed as to be movable relatively to the conveying line in the transverse direction thereof to an extent limited by lateral abutments, so that in curved regions of the conveying line it can move to the inner side of the curve, preferably so as to extend at least approximately as a tangent to the inner curve arc. Preferably the flexible tension element consists of a chain, especially a round-link chain, although ropes and the like may be used instead. The lateral freedom of movement is preferably over substantially the lateral width of the conveyor line itself. This tension or drawing element is arranged so that when the curve conveyor is advanced the pulling forces required for overcoming resistance to travel are transmitted, relieving the scraper chain, to the rear end of the conveyor where they act as thrust forces. Thus it is possible both to pull and push the conveyor line when advancing. The interposing of the tension element, transmitting pulling forces, also relieves the scraper chain band of such pulling forces at least to a substantial extent. Correspondingly a further result is that the chain drive and return, e.g. chain starwheels and their associated chain drum bearings, are also relieved of load. Any chain tensioning device ma also be relieved of these forces. The curve conveyor can thus be displaced without it being absolutely necessary to halt conveying work to do so. The arrangement may also advantageously be made such that the curve conveyor can be displaced longitudinally in either direction. Since, when the conveyor line is following a curved course, the tension element can at least approximately set itself on or near the tangential line relatively to the inner arc of the curve (in other words, on to a chord of the arc formed by the conveyor axis), the pulling forces introduced into the tension element tend to eliminate the restoring forces which tend to re-adjust the curve conveyor back on to the straight course, i.e. the curve conveyor is stabilised in its existing curved disposition. It is preferred to attach or anchor the tension element at its ends to the relevant machine frame of the curve conveyor. A variable length or re-tensionable anchoring system is not always necessary, but may be provided if desired. The length of the tension element between its fixed ends is adapted to the length of the curve conveyor and the size of the attainable curve radii. The length need be no greater than or not substantially greater than the length of the conveying line bridged by the tension element when situated on a straight course with the channel sections fully butting against one another. The arrangement is also advantageously such that the tension element is spaced below the conveying channel or run in the conveying line. In a preferred version, certain individual conveyor segments are coupled with the tension element at points along its length. Connection is preferably at regular intervals, e.g. such that every third to tenth conveyor segment is connected in longitudinal force-transmitting manner to the tension element. This allows the forces which are required for overcoming the resistance to displacement to be distributed along the conveying line of the curve conveyor. It will be apparent that the coupling of the individual conveyor segments to the tension element should be made such that the transverse freedom of the tension element relative to the conveying line is not substantially hindered. For example, it may be by means of coupling elements which are connected, preferably by a pivotable connection, to the tension element and which can run via rollers or sliding elements laterally along a transverse member e.g. rod or the like of the relevant conveyor segment, in longitudinal force-transmitting manner. These transverse rods may be the wheel axles for running wheels with which the conveying line is supported for travelling movement. In order to allow the curve conveyor to travel along curves in a controlled manner it is advantageous in use to provide in each curve region curve guide elements e.g. anchorable frame guides or the like, such as are known from DE-OS 37 27 272. The conveyor may have, at at least one of its two end regions, a magazine for the accommodation of a plurality of such curve guide units which can be used as and when needed, but otherwise can be carried along in the magazine during travel. Preferably the curve guide units consist of gantry-form guide frames which advantageously are clampable between roof and floor and for this purpose advantageously have props which can be extended towards the floor. The conveying line is preferably provided with a guideway along which the individual curve guide units can be guided from the magazine to the respective place of us and vice versa. In a particular simple arrangement, the curve guide units used are gantry-type frames which extend about the conveying line of the curve conveyor and bear on the guideway by means of running and/or guide wheels. The guideway can be formed of parts of the conveyor segments which project about the conveying channel e.g. upstanding side walls of the conveyor segments, which in this case form a supporting frame for the individual channel or run sections of the conveyor.

Verification

US Patent Issued on July 16, 1991 Estimated Patent Expiration Date: February 26, 2010Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.