Conveyor belt cleaner scraper blade and assembly

A replaceable conveyor scraping blade has a blade body extending lengthwise along a longitudinal axis. The blade body is produced from a material having a flexible, elastic quality. The blade body comprises a base portion, and intermediate portion, and a terminal end. The base portion is attachable to a tensioning device for biasing the blade body against a conveyor belt. The intermediate portion is generally arcuate and comprises a leading surface and a trailing surface. The leading surface extends upwardly relative to the base portion. The trailing surface is opposite the leading surface. It also extends upwardly relative to the base portion and has a scalloped surface when viewed in cross-section extending lengthwise along the longitudinal axis. The terminal end has a scraping surface separating an uppermost portion of the trailing surface from an uppermost portion of the leading surface.

CROSS-REFERENCE TO RELATED APPLICATIONS

FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

TECHNICAL FIELD

The invention relates to conveyor belt cleaning systems. More particularly, the present invention is directed to an improved conveyor belt scraper blade and assembly.

BACKGROUND OF THE INVENTION

In the art of mining, conveyor belts are used to receive, transport, and deliver mined substances such as coal, ore, and the like from one location to another. For example, conveyor belts may be used to carry mined material out of a mine and deliver it to a location external to the mine such as a holding area or transport vehicle. Conveyor belts may also be employed for carrying materials between processes. These belts can be extremely long and can move the material at high linear speeds.

Typically, driving mechanisms such as motorized wheels or pulleys are used to transfer movement to the conveyor belts. Generally, one driving mechanism is located at an entry end of the conveyor belt where material are received onto the belt and another driving mechanism is located at a delivery end of the belt where the mined material is deposited from the belt to an external location. One of the driving mechanisms may be free-wheeling if the appropriate to the specific use.

During the transfer process, it is not uncommon for mined material residue to adhere, cling, or remain on the belt as the belt makes its return to the entry end from the delivery end, subsequent to the bulk of the transported material being deposited from the belt.

The process is somewhat complicated in high dust applications such as coal mining because the liquid is often used to suppress dust. The liquid causes increased residue to build on the conveyor belt. This material can transfer to and build up on pulleys, rollers, idlers, and bearings. This build up of material causes excessive wear at a minimum and can cause seizing in bearings and may lead to fires, a catastrophic result. The mined material can have huge fluctuations on moisture content (% water), and water is often added to the coal during the mining/handling processes.

Belt scrapers are often employed to remove this material from the conveyor belts to prevent the transfer to other elements of the conveying system, thereby preventing damage to those elements. Scraper blades are attached to a tensioner unit which is used to maintain contact between the scraper blades and the belt, typically at delivery end wheel or on the return run of the belt. The dynamic nature of the environment and the abrasive nature of the materials being carried by the endless belt require belt scrapers that are durable and that can be maintained in contact with the belt with consistent pressure. The belt scrapers are expendable elements of the system and any economy that can be achieved with the belt scrapers is an improvement in the economic efficiency of the system.

The present invention is provided to solve the problems discussed above and other problems, and to provide advantages and aspects not provided by prior conveyor belt cleaner scraper blades and assemblies of this type. A full discussion of the features and advantages of the present invention is deferred to the following detailed description, which proceeds with reference to the accompanying drawings.

SUMMARY OF THE INVENTION

One aspect of the present invention is directed to a replaceable conveyor scraping blade. The blade comprises a blade body which extends lengthwise along a longitudinal axis and is produced from a material having a flexible and/or elastic quality. The blade body comprises a base portion, generally arcuate intermediate portion, and a terminal end. The base portion is attachable to a tensioning device which biases the blade body against a conveyor belt. The intermediate portion comprises a first surface extending upwardly relative to the base portion and a second surface opposite the first surface. The second surface also extends upwardly relative to the base portion and has a scalloped surface when viewed in cross-section extending lengthwise along the longitudinal axis. The terminal end has a scraping surface separating an uppermost portion of the second surface from an uppermost portion of the first surface.

The first aspect of the invention may include one or more of the following features, alone or in any reasonable combination. The uppermost portion of the second surface may be higher than the uppermost portion of the first surface relative to the base portion. The scalloped surface may comprise a plurality of convex and concave sub-surfaces. Each convex sub-surface may extend lengthwise along the longitudinal axis. Each concave sub-surface may extend lengthwise along the longitudinal axis. Each concave sub-surface may be separated from an adjacent concave sub-surface by a convex sub-surface. The first surface may be arcuately shaped. The scraping surface may be angled greater than 0° from a vertical axis passing through an edge point at which the scraping surface and the second surface intersect. The intermediate portion may further comprise a neck having a reduced width to provide a region of reduced resistance to deflection for allowing the terminal end and intermediate portion to deflect about the base portion. The base portion may comprise a slot extending along the longitudinal axis for mounting the replaceable conveyor scraping blade to a tensioner. The slot may be lined with a rigid member. The slot may have a pair of opposing openings forming a substantially T-shaped cross-section. The scalloped surface may comprise a visual level-of-wear indicator.

A second aspect of the present invention is directed to a replaceable conveyor scraping blade. The blade comprises a blade body which comprises a base portion, an intermediate portion, and a terminal end. The blade body extends lengthwise along a longitudinal axis and is produced from a material having a flexible, elastic quality. The base portion is attachable to a tensioning device for biasing the blade body against a conveyor belt. The intermediate portion is generally arcuate and comprises a first surface which extends upwardly relative to the base portion and a generally arcuate second surface opposite the first surface. The second surface also extends upwardly relative to the base portion and has a plurality of outwardly convex surfaces extending lengthwise along the longitudinal axis. Each outwardly convex surface is separated from an adjacent outwardly convex surface by a inwardly concave surface. The terminal end has a scraping surface separating an uppermost portion of the second surface from an uppermost portion of the first surface.

The second aspect of the present invention may include one or more of the following features, alone or in any reasonable combination. The plurality of outwardly convex surfaces and the inwardly concave surface may form a scalloped surface in cross-section. The uppermost portion of the second surface may be elevated higher than the uppermost portion of the first surface relative to the base portion. The first surface may be arcuately shaped. The intermediate portion may further comprise a neck having a reduced width to provide a region of reduced resistance to deflection for allowing the terminal end and intermediate portion to deflect about the base portion.

Another aspect of the present invention is directed to a replaceable conveyor scraping blade. The blade comprises a blade body extending lengthwise along a longitudinal axis and produced from a material having a flexible, elastic quality. The blade body comprises a base portion, an intermediate portion, and a terminal end. The base portion is attachable to a tensioning device for biasing the blade body against a conveyor belt. The intermediate portion is generally arcuate and comprises a first surface and a second surface. The first surface extends upwardly relative to the base portion. The second surface is opposite the first surface and is generally arcuate. The second surface also extends upwardly relative to the base portion and has a plurality of arcuate sub-surfaces extending lengthwise along the longitudinal axis. Each arcuate sub-surface has a height less than a height of the generally arcuate second surface. The terminal end has a scraping surface separating an uppermost portion of the second surface from an uppermost portion of the first surface.

Another aspect of the present invention is directed to a replaceable conveyor scraping blade. The blade comprises a blade body extending lengthwise along a longitudinal axis and produced from a material having a flexible, elastic quality. The blade body comprises a base portion, an intermediate portion, and a terminal end. The base portion is attachable to a tensioning device for biasing the blade body against a conveyor belt. The intermediate portion is generally arcuate and comprises a first surface and a second surface. The first surface extends upwardly relative to the base portion. The second surface is generally arcuate and is located opposite the first surface. The second surface extends upwardly relative to the base portion and has a visual wear-indicator for communicating a level of wear of the scraping blade resulting from frictional engagement with a conveyor belt. The terminal end has a scraping surface separating an uppermost portion of the second surface from an uppermost portion of the first surface.

DETAILED DESCRIPTION

Referring toFIGS. 1-7, a conveyor belt cleaning assembly10of the present invention is illustrated. The assembly10includes a scraper blade14attached to an elongate shaft18that is adapted to be rotatably mounted to a support member at each end and that is adapted to be selectively rotated about an axis50running lengthwise through the shaft18. Rotation or at least partial rotation is controlled by a tensioner22having adjustable, spring-loaded biasing units26located at opposing ends of the shaft18and attached thereto. A mounting member30is fixedly attached to the shaft18and extends outwardly therefrom, preferably in the form of a fin-like structure extending radially outwardly from the shaft18. The mounting member22has apertures for receiving a fastener, such as a bolt, pin, cotter key, or the like, for attachment with the scraper blade14.

The scraper blade14is removably attached to the mounting member30such that the blade14extends radially outwardly from the shaft18. A purpose of the scraper blade14is, when biased or spring-loaded against a moving conveyor, the blade14frictionally engages the conveyor belt100to liberate or free materials adhered to the belt100. Blade engagement with the belt100is illustrated in, for example,FIG. 13.

The scraper blade14comprises a blade body which may be manufactured from a polyurethane or rubber of reasonable flexibility and rigidity. The blade14may comprise a plurality of substantially identical horizontally aligned segments; however, the blade of the present invention is preferably a unitary member having a length generally shorter than the shaft18and a height sufficient to contact a conveyor belt during use while providing a sufficient useful life with a desired amount of deflection. Accordingly, the height of the blade14may be varied depending on design parameters and need. It is contemplated that the height of the blade may vary from about 5.0 inches to about 20 inches, a more preferably from about 5.8 inches to about 14.6 inches. The blade14is a generally arcuate shape extending upwardly from a base portion34through an intermediate portion38and terminating at terminal end42.

The base portion34is adapted to be removably attached to the mounting member22. Accordingly, the base portion has a slot46for receiving the mounting member22. The slot46is generally defined by an aluminum extrusion48imbedded in the base portion34. In one embodiment, the slot46has an additional opening54extending outwardly from a main slot portion for receiving a complimentary leg58extending outwardly from the mounting member22. In another embodiment, the slot has a plurality of openings54for receiving an equal number of complimentary legs58extending outwardly from the mounting member22. In an embodiment illustrated inFIG. 12, the slot54and the openings54form a T-shape or mushroom-shape, and the mounting member22has an equal number of legs58for seating within the openings54.

The intermediate portion38has a lengthwise neck62of reduced thickness of the blade material. A front or leading surface66may be generally smooth and extends arcuately and upwardly from the neck62to the terminal end42. A rear or trailing surface70is opposite the front surface66and extends upwardly and arcuately from the neck62to the terminal end42. The rear surface70is generally scalloped having a plurality of lengthwise arcuate surfaces74a lengthwise scalloped appearance. Each arcuate surface74may be substantially formed by an arc of a circle or other suitable conic section when viewed in cross-section. Preferably, each arcuate surface74forms an outwardly convex surface which is joined to an adjacent arcuate surface74by an inwardly concave surface76. The rear surface70ends at an upper most edge point of the terminal end42, such that, from the rear view, the terminal end42of the blade14is no more than a line78.

The terminal end42has a scraping surface82extending downwardly from the edge78at the uppermost portion of the rear surface70. The scraping surface82is also angled greater than 0° relative to a vertical axis intersecting the edge78. The scraping surface82terminates at a lower edge86located at an uppermost portion of the front or leading surface66of the blade14.

Stated another way, a blade14of the present invention has a unique blade design. The unique blade design comprises a polyurethane or rubber blade body (a reasonably flexible member) which extends lengthwise along a longitudinal axis and an aluminum extrusion or rigid insert piece for mounting on the cross member or shaft18. A cross member mounting allows the blade body to be actuated against a conveyor belt100and scrape material that adheres to the exterior of the belt100in material handling applications. This removes carry-back material from the belt100. Carry-back material is material that adheres to the belt as it traverses from the carrying side to the return side.

The blade body consists of a base region34having an embedded rigid mounting member48, generally a metallic member, preferably an aluminum extrusion. The embedded rigid mounting member48may also be produced from a steel, polymer, plastic, ceramic, or the like. The blade body has a narrowing cross section (the neck62) near the base region34that allows for preferential flexing and bending during operation to minimize differential pressure at the belt contact point, minimizing belt indentation. The blade body has a scalloped outer profile consisting of series of alternating convex and concave segments. The segments provide a visual indication of wear life remaining on the blade14because as the blade14wears, the friction between the scraping surface82and the belt100causes removal of the blade body which reduces the number of segments over time. Thus, the upper edge78marking the terminal end42from the intermediate section48on the trailing surface70changes over time with use moving downwardly towards the base34and decreasing the number of outwardly convex segments and reducing the height of the trailing surface70. The lower edge86may undergo the same movement downwardly towards the base34as the blade wears, thus reducing the height of the leading surface66.

The scraping surface82has a variable cleaning/contact angle φ. This allows a renewable or variable tip to prevent blade splitting and has a variable cross-section to “smooth out” tensioning variation. The scallops of the scalloped surface, e.g. the alternating convex and concave surfaces or segments, provide a variable area which smoothes out peaks and valleys of mechanical pressure application by giving slight variations in contact across area/cross section. Thus, an important aspect of the invention is a slightly varying cross-sectional width along the height of intermediate portion of the blade and the terminal end as the blade undergoes wear, as it follows that as wear occurs the terminal end migrates downwardly relative to, and at the expense of, the height of the intermediate portion. The scraping surface82further has an offset inner profile giving the blade body a reasonably constant cross-section from the scraping surface82back to the trailing surface70during its usable life. The variable contact angle φ may be increased over time and is measured from a generally horizontal axis drawn perpendicular to the tangent at the location on the belt where a new blade's upper edge78engages the belt100when initially placed into service. The angle φ can be varied from less than 25° to greater than 50°, preferably from 0° to 50°. (SeeFIG. 18). The scraping surface82also has a profiled tip, which is tapered for initial contact against the conveyor belt100and allows for gradual wear in that ensures good surface contact is attained and maintained.

FIGS. 13-15illustrate the forces acting the blade14and a means for adjusting the force using an existing tensioning device88. A resultant force FRis the product of a force FMprovided by the carry-over material on the belt100and a normal force FNprovided by a setting F2variable by adjusting a spring-loaded nut90on the existing tensioner88. Thus, the magnitude and direction of the resultant force FRvector can be varied by a control on the tensioner88to optimize performance of the blade14.

The tensioner22is provided for, among other things, supporting the shaft18, biasing the blade14against the conveyor belt100(counterclockwise in the embodiment illustrated inFIGS. 1-7), and adjusting the force and angle with which a scraping surface82strikes or engages the belt100. Once the blade14is spent, the tensioner22rotates the spent blade14through a contact zone with the belt100to a position such that the blade18is spaced from any contact with the belt100as illustrated inFIGS. 15 and 16.

The terms “first,” “second,” “upper,” “lower,” “top,” “bottom,” etc., when used, are for illustrative purposes relative to other elements only and are not intended to limit the embodiments in any way. The term “plurality” as used herein is intended to indicate any number greater than one, either disjunctively or conjunctively as necessary, up to an infinite number. The terms “joined,” “attached,” and/or “connected” as used herein are intended to put or bring two elements together so as to form a unit, and any number of elements, devices, fasteners, etc. may be provided between the joined or connected elements unless otherwise specified by the use of the term “directly” and/or supported by the drawings.