GB2076353A - Scraper blade - Google Patents

Abstract

The invention relates to a scraper blade for a conveyor belt. Conventionally conveyor blade scrapers are mounted in the vicinity of the discharge end and it is usual to resiliently mount such scrapers to maintain contact between the scraper blade and the belt to accommodate wear on the blade, and to allow the passage of a joint in the belt past the scraper blade. This however does not avoid damage to the joint or to the blade or even to the belt surface when the blade is forcibly displaced from the surface of the belt or returns to the belt surface after passage of a joint. Not only is there possible premature failure of either the belt, joint or scraper, there is also a noise problem resulting from the blade repeatedly striking the belt surface. The object of the invention is to avoid such problems, which objective is met by a scraper blade having a body portion (1) with a scraper edge (2, 3) at at least one side and at least one projecting lifting finger (5, 6) extending beyond the scraper edge to contact the belt surface in advance of the edge of the scraper. <IMAGE>

Description

SPECIFICATION Scraper blade Tbis invention relates to a scraper blade for scraping the carrying surface of a belt conveyor. Conventionally such blades are located in, the vicinity of the discharge end of the conveyor with a view to avoiding as far as possible fines, or other adhering material, being carried back with the return run of the belt, which if unchecked would lead to spillage and the unnecessary consumption of additional power to drive the belt.

It is necessary of course to provide in any belt at least one joint, which may incorporate belt fastening elements, e.g., staples, hooks, or plates, or alternatively which may be a vulcanised joint, but with whatever form of joint that is employed, there is invariably a projection beyond the carrying surface in the area of the joint. It is also necessary for the scraper blades to be displaceably mounted, usually resiliently, under the influence of leaf or coil springs, or sometimes by a dead weight, firstly to maintain contact between the scraper blade and the belt surface, secondly to accommodate wear on the blade (both of which aim at ensuring an adequate scraping action) and thirdly to accommodate the passage of a joint beyond the scraper blade.The displaceable mounting does not however preclude the possibility of damage to the joint, to the blade, or to the belt surface when the blade is forcibly displaced from the belt surface by the arrival at the blade of a joint, or when the blade returns to the belt surface after passage of the joint. Apart from the possibility of premature failure of either the joint or the blade resulting from damage, there is also a noise problem resulting from the blade restriking the belt surface after passage of the joint.

According to the present invention, a scraper blade for scraping the carrying surface of a conveyor belt comprises an elongate body portion having a longitudinally extending scraper edge at at least one side, with at least one projecting lifting finger attached to the body portion and extending beyond the or each scraper edge, and adapted, in use, to make contact with the belt surface to be scraped in advance of the scraping edge of the blade.

Thus, due to the provision and advanced position of the lifting finger, the latter is first struck by the joint and is therefore displaced from the belt surface, in turn lifting the entire blade from the belt surface for passage of the joint beyond the blade, in contrast to prior art arrangements which allow the entire scraper edge of a blade to be struck by the joint. It follows of course that the extent of projection of the lifting finger is to some extent dictated by the linear velocity of the belt to ensure that the blade is lifted only for a sufficient time to ensure passage of the joint beyond the blade.

Preferably, two lifting fingers are provided, one located towards each end of the body portion. The latter may be of synthetic plastics or hard rubber material and may incorporate an elongate metallic reinforcing and/or supporting strip, which may be bonded to the plastics or hard rubber extending the length of the blade, the cross-section of which may be in accordance with British Patent Specification 1,515,061.

In principle, the or each projecting finger could take the form of a separate element secured, e.g., by bolts, to the blade, or if the blade is of synthetic plastics material, the or each finger may be integrally moulded with the plastics of the blade. With whatever construction is employed, it is highly advantageous for the material of the or each finger to be the same as that employed for the blade, so that both the finger(s) and the blade exhibit the same wear characteristics.

The scraping edge should of course be of a length exceeding the width of the belt surface to be scraped, while the blade may be reversible if it incorporates two opposite, longitudinally extending scraper edges, in which case at least one lifting finger would extend laterally beyond each edge.

One embodiment of the invention will now be described by way of example only with reference to the accompanying drawings, in which Figure 1 is a plan view of a scraper blade according to the invention; and Figure 2 is a schematic side elevation of the blade of Fig. 1 located against a conveyor belt return loop.

In the drawings, a synthetic plastics scraper blade has a body portion 1 of rectangular form with scraper edges 2 and 3 to each side of the body portion. Secured to the back face of the body portion is a metallic supporting strip 4, to v,hich are secured two synthetic plastics lifting fingers 5, 6 both of which project beyond the scraper edges 2, 3.

As is shown by Fig. 2 the scraper blade is mounted on a spring support 7 such that one scraper edge 2 is in contact with the return loop 8 of a conveyor belt 9, the extent of projection of the fingers 5, 6 and the angle of the scraper to the belt being such that the ends of the fingers are also in contact with the surface of the return loop of the belt.

Thus, as a joint in the belt passes round the return loop, it first strikes the lifting fingers which then lift the scraper blade against the action of the spring to allow the belt joint to pass below the scraper blade, without striking the edge of the scraper blade. The extent of projection of the fingers is also partly determined by the linear velocity of the conveyor belt, so that the scraper blade is lowered into contact with the belt surface immediately the belt joint has passed the scraper edge.

Thus, the lifting of the scraper by the fingers prevents both damage of a joint by the scraper edge and damage of the scraper edge by the joint, thereby preventing premature failure of both, and additionally reduces noise significantly by preventing the scraper blade from hitting the belt surface after the passage of a joint.

Claims (6)

1. A scraper blade for scraping the carrying surface of a conveyor belt, comprises an elongate body portion having a longitudinally extending scraper edge at at least one side, with at least one projecting lifting finger attached to the body portion and extending beyond the or each scraper edge, and adapted, in use, to make contact with the belt surface to be scraped in advance of the scraping edge of the blade.

2. A scraper blade as in Claim 1, wherein two lifting fingers are provided, one located towards each end of the body portion.

3. A scraper blade as in Claim 1 or Claim 2, wherein the body portion and the fingers are formed from materials having similar wear properties.

4. A scraper blade as in any of Claims 1 to 3, wherein the or each finger is a separate element suitably secured to the body portion.

5. A scraper blade as in any of Claims 1 to 3, wherein the body portion and the or each projecting finger is formed from synthetic plastics material with the or each finger integrally moulded with the body portion.

6. A scraper blade substantially as hereinbefore described with reference to the accompanying drawing.