US3895982A

US3895982A - Wear protection elements for planar or curved surfaces exposed to abrasion

Info

Publication number: US3895982A
Application number: US308858A
Authority: US
Inventors: Bo Klas Gerhard Persson
Original assignee: Trelleborgs Gummifabriks AB
Current assignee: Trelleborgs Gummifabriks AB
Priority date: 1970-12-15
Filing date: 1972-11-22
Publication date: 1975-07-22
Anticipated expiration: 1992-07-22

Abstract

A wear protection element adapted to varied planar and curved surfaces, made from an elastomer, preferably natural or synthetic rubber, and having sheet-like body member and projections or ridges integral with and projecting from the surface of the sheet-like body member. The projections which may segmented or continuous ridges have at least two side surfaces with different angles of inclination relative to the surface of the sheet-like member having the projections or ridges thereon.

Description

United States Patent 1191 Persson 1 1 WEAR PROTECTION ELEMENTS FOR PLANAR OR CURVED SURFACES EXPOSED TO ABRASION (75] Inventor: Bo Klas Gerhard Persson.

Trelleborg, Sweden [73] Assignee: Trelleborgs Gummifabriks Aktiebolag, Trelleborg, Sweden [22] Filed: Nov. 22, 1972 [2]] Appl. No.: 308,858

Related U.S. Application Data [63] Continuation-in-part of Ser. No. 98,295, Dec. 15,

1970, abandoned.

[52] U.S. Cl. 156/71; 156/137; 156/297; 161/116; 198/198; 241/182; 241/294;

241/300; 24l/D1G. 30

[51] Int. Cl. B321) 31/00 [58] Field of Search l61/116,123,145, 165; 156/71, 297, 299, 137; 241/103, 182, 183,

294, 300, DIG. 30; 198/198 [56] References Cited UNITED STATES PATENTS 1,853,249 4/1932 Ainley .1 241/DlG1 30 1451 July 22, 1975 2,004,573 6/1935 Galley et al 241/DIG. 30 2,064,554 12/1936 Mahoney et a1. 24l/D1G. 30

2,069,720 2/1937 Harvey 1 1 1 161/123 2,366,209 1/1945 Morris l 161/239 2,784,835 3/1957 Dixon 161/123 3,001,730 9/1961 Daman 241/183 3,085,676 4/1963 Hinchcliffe 198/198 3,378,209 4/1968 Crocheron 241/182 Primary ExaminerGeorge F. Lesmes Assistant Examiner-Stanley S. Silverman Attorney, Agent, or Firm-Browne, Beverid'ge, DeGrandi & Kline {5 7} ABSTRACT A wear protection element adapted to varied planar and curved surfaces, made from an elastomer, preferably natural or synthetic rubber, and having sheet-like body member and projections or ridges integral with and projecting from the surface of the sheet-like body member. The projections which may segmented or continuous ridges have at least two side surfaces with different angles of inclination relative to the surface of the sheet-like member having the projections or ridges thereon.

7 Claims, 7 Drawing Figures WEAR PROTECTION ELEMENTS FOR PLANAR OR CURVED SURFACES EXPOSED TO ABRASION This is a continuation-in-part application of my earlier application Ser. No. 98.295 filed Dec. 15, 1970, now abandoned.

The surface of chutes, unloading stations for conveyors, baffle walls, screens and the like are exposed to wear or abrasion by material flowing along the surfaces. To increase the wear resistance of the surfaces prior art has already suggested the use of so-called wear protection elements of natural or synthetic rubber and other elastomers. For certain purposes, prior art has also shown a retardation or agitation of the material flowing along the surfaces in question, and to satisfy these purposes prior art has arranged projections that are either separate from or integral with the wear protection element; as a rule these projections have been in the shape of elongated ridges or ribs. These projections, ridges or ribs, however, are exposed to a more vigorous wear or abrasion than the remaining wear protection element, and it has therefore been a long-felt desideratum to improve the wearing strength of such means. To this end, prior art has suggested to use of sheathings of for instance cemented carbides or ceramic at the most exposed points. Applicant has also found that the best wearing strength of the projections and thus of the entire wear protection element can be attained by taking measures such that the abrading material will stike the surface of the wear protection element at such an angle of incidence that the angle made between the wear protection element surface struck by a particle of abrading material and the force resultant with which the particle upon sliding movement or impact acts upon said surface is either within the range of -5 or 70-90 when the wear protection element is formed by an elastomer, particularly natural and synthetic rubber. If the angle in question were within the approximate range of lO-30 the elastomeric material would, however, be very rapidly worn or abraded. It should be mentioned here that within the ranges of 7 1 0 and 3050 steel normally has a higher wearing strength than wear-resistant rubber, whereas wear resistant rubber within the above mentioned ranges of 05 and 70-90 is considerably more wear resistant than steel. Therefore, the present invention, while exploiting said insight into the wearing strength of elastorneric bodies, has for its object to permit manufacturing wear protection elements as standardized piece goods with as large a usefulness as possible. To attain this, the wear protection element according to the invention is formed with projections or ridges projecting from that surface or the wear protection element which is exposed to abrasion, and the free ends of said projections or ridges as viewed in an elevation at right angles to the surface of the wear protection element, terminate within the base surface of the projections or ridges but is located eccentrically in relation to said base surface so that the projections or ridges will have at least two oblique lateral surfaces with different angles of inclination relative to the surface of the wear protection element having the projections or ridges thereon.

Some embodiments of wear protection elements according to the invention will be described in detail hereinbelow with reference to the accompanying drawing in which:

FIG. 1 is a cross section of a fluted wear protection element according to the invention;

FIG. 2 shows the fluted side of said wear protection element;

FIG. 3 shows another embodiment of the wear protection element illustrated in FIG. 1;

FIG. 4 shows a plan view of an oblique rectangular, possibly truncated pyramid which forms one of a great many projections which are arranged in an optional pattern on the surface of another embodiment of the wear protection element according to the invention;

FIG. 5 shows a section of line VV in FIG. 4;

FIG. 6 shows a section on line VlVl in FIG. 4;

FIG. 7 exemplifies the use of the wear protection element illustrated in FIG. I.

The wear protection element illustrated in FIG. I is made of an elastomer, particularly natural or synthetic rubber, which has been mixed with the customary additions such as active carbon black, e.g. HAF, SAF or ISAF black, and the like to obtain as especially high abrasion strength. The wear protection element has ridges 10 and valleys or flutes 11 which at the manufacture of the wear protection element by extrusion are in the form of continuous ridges and valleys or flutes. According to the invention, the two

longitudinal side surfaces

12, 13 of the ridges or ribs have different angles of inclination relative to the main plane of the wear protection element so that said wear protection element, upon reversal, can provide two different angles of incidence for the material which, either for sliding movement or impact, strikes and moves along the wear protection element. In this way the usefulness of the wear protection element which is manufactured as piece goods, is considerably increased whereby the manufacturing and storage cost and thus the prime cost of the wearing element are reduced. In the embodiment illustrated the apices of the ridges have been located eccentrically in relation to the base surface in such a way that the angles of the two

longitudinal side surfaces

12, 13 with the main plane of the wear protection element amount to 35 and respectively. Naturally, other complementary angles also are conceivable as illustrated in the remaining figures in which the apices of the ridges are placed eccentrically in relation to the base surface of the ribs.

As will appear from FIG. 3 the ridges need not be made continuous, but can also be formed as short ridges 10' arranged in rows, and the ridges in adjoining rows, as shown in FIG. 3, are preferably offset longitudinally in relation to each other to provide a zig-zag pattern. A great advantage of providing short separate ridges instead of continuous ridges is that the flexibility of the ridges is thereby increased without it being necessary to mix a softer quality of the wear or abrasion resistant rubber proper. Since a harder elastomer quality has a higher crushing strength than a softer quality, it is thus possible, while retaining the harder elastomer quality and thereby the higher crushing strength, nevertheless to attain increased flexibility and thus further increase abrading resistance when the ridges are formed as short and free-standing elements in accordance with FIG. 3.

The same advantageous effect can be attained if instead of continuous ridges 10 one uses possibly truncated, preferably rectangular pyramids 14 as projections on the surface of the wear protection element. FIGS. 4-6 show a suitable embodiment of an oblique pyramid 14, the apex 15 of which is placed within the base surface of the pyramid in such a way that the four side surfaces of the pyramid will have different angles of inclination relative to the base surface. In the embodiment shown, the four side surfaces make angles of 30, 40, 50 and 60, respectively. with the base surface. Same as for the short ridges in FIG. 3, the pyramids may and should be staggered in relation to each other to provide the best possible protective effect, retarding effect and possibly agitation effect.

As already mentioned, the pyramids in FIGS. 4-6 can be formed as truncated pyramids, and it is indicated by broken lines l6 in FIGS. 4-6 how the truncation of the pyramids can be done.

FIG. 7 shows an example of how a variant of the wear protection element illustrated in FIGS. l-3 can be used to protect a sloping or inclined surface against abrasion. The wear protection element is here placed on an oblique metal sheet 17 to protect it, the side surface 12 of the ridges being turned upwardly in order that the abrading material falling against the wear protection element in the direction of the arrow 18 shall strike the rubber surface at an angle of incidence of 85, then to slide downwardly along the wearing element in a cascade-like manner. In this instance use is thus made of the wear protection element for the protection of a surface which is inclined at a 40 angle to the horizontal, whereas when using the side surface 13 of the ridges one can utilize the wear protection element under otherwise similar conditions for the protection of a surface which is inclined at a 60 angle to the horizontal.

It will be noted that FIGS. 1 and 4-7 each illustrate angles which the opposite faces of the ridges make with the substrate to equal 90, thus being complementary, and that the apex angles are accordingly 90. In FIG. 7 the inclined substrate shows material impingement along the direction 18 which is substantially normal to the impinging faces and substantially at grasing or sliding angle to the faces opposite the impinging faces. When the illustrated wear surface is applied to a conveyor inclined as in FIG. 7, falling material according to 18 strikes the wear surfaces either nearly perpendicularly or at a sliding angle. The configurations of other Figures present impact angles of the aforesaid 70 90 to material arriving from different characteristic directions, for maximum wear for a range of angles of material impact upon the general plane of the surface while the opposite faces of the same ridges will be at sliding angles of substantially 5.

In summary of the present invention discloses that hardened steel or abrasion-resistant materials subjected to impact by abrasive particles are more durable than resilient faced surfaces for angles of impact between about 70 and l 0 to the plane of the surface, but that certain elastomeric materials, including rubber compositions, can be superior to hardened surfaces at impact angles of 70-90 and at grasing angles less than 5. Neither material type is superior for all angles. inclined conveyors for vertical impingement and material passages on which material arrives in an inclined direc tion have heretofore employed hardened surfaces. It is found they have better durability under impact at angles of 5-l0 to about 70 from the plane of the surface as a whole, but that ridged surfaces comprising resilient covering on the general plane of the surface are more durable than the hardened surfaces if the angles of impact can be made 70-90 or 05 by selection of ridge geometry to effect the desired angles of impact. Uniform ridges of triangular form are found best, but obviously a single angle of faces relative to the base surface is not effective for more than a fraction of the possible angles of impact between 5 or 10 and 70. This invention provides a method of manufacturing a resilient surface which can be used in two different ranges of angle for a continuous ridge extrusion and four different ranges of angles for a pyramidal set of wear elements. For example, a set of ridge faces at 30 provides for 70 to 90 impact for particles arriving at inclinations between 10 and 50, while a face (opposite the 30 face) provides for to 90 impact for particles arriving at inclinations to the base surface between 40 and Thus, by reversing the formed ridges of 60 and 30 slope relative to the base, the same ridge elements may be attached to the base surface in a manner to provide 70 to impact throughout all possible angles of inclination of arriving particles.

Other angles such as 25 and 65 or 40 and 50 are selectable to provide as nearly average perpendicular impact as possible for the best results. It is also noted that the durability under sliding or grasing impacts is more critically determined, since sliding impingement at greater than 5 7 may be no better than the durability of hardened surfaces. Accordingly, the other angles than 30 and 60 have advantages in that some material always strikes the ridge faces opposite the intended nearly perpendicular faces. To achieve the full advantage possible in the use of the invention it is seen that apex angles of about 90 provide the grasing incidence angles for the material sliding faces when the impact faces are close to normal to the arriving particles.

In a right triangular ridge shape it will be seen that assymetrical faces are at greater than 45 and less than 45 from the base plane, the faces presented to the direction of impact being selected to provide more nearly normal impact, the steeper face being presented to impacts at angles less than 45 to the base plane.

Thus a method of preparing a resilient faced impact surface of longer durability than hardened steel, etc., is provided by attaching unsymmetrical nearly righttriangular ridges to the base surface, selectively according to the surface inclination thereof for vertically falling material or according to the angle of arriving material so as to present impact faces at 70 to 90 and sliding faces as nearly as possible to grasing incidence, the step of selection and application of the ridged elements being according to use. A single form of ridge such as 30 and 60 applied according to the foregoing is effective for most uses to produce a product superior to hardened surfaces, and attaching pyramidal elements according to the same principle provides a still further improvement in which the resulting protected surface can move in four directions to closely approach normal and grasing impacts for four ranges of impact angle.

What we claim and desire to secure by Letters Patent l. The method of preparing a durable elastomeric surface for receiving abrasive material falling thereon having wear resistance enhanced by control of the angle of impact of said material thereon, which surface has lower wear resistance than conventional hardened materials for a range of angles between grazing and perpendicular impact, comprising the steps of observing for a particular material flow and surface motion in an installation a characteristic angle of impact of a predominant portion of said material upon said surface generally, selecting a set of wear resistant resilient elements having like forward and after faces meeting asymmetrically a ridged vertex, the respective forward and after faces making differing angles to the perpendicular to said surface, securing to said surface said elements in mutually parallel relation oriented transversely to the linear motion of the surface when moving, and to the direction of impact of material when fixedly inclined, to effect relative motion between the elements arranged on said surface and motion of said material falling thereon to cause said characteristic angle to lie substantially within degrees of said perpendicular to said forward faces.

2. The method of claim 1, said characteristic angle being approximately 45 from said surface generally, said after faces then being secured at an angle to the surface between 40 and 50, to cause said material to stike said after faces at a grazing incidence.

3. The method of claim 1 for a said characteristic angle of 45 including securing said forward faces at substantially 45 1 20 from the surface and within 20 of perpendicular to said characteristic angle of impact.

4. The method of claim 3 including selecting and orienting elements with said after faces within 5 of said angle.

5. The method of claim 1, said observed characteristic angle being at substantially 30 1 20 to said surface including arranging said forward faces at substantially 20 to said surface.

6. The method of claim 5 wherein said after faces are arranged within 5 of said angle 7. The method of claim 1 said observed angle being at substantially 60 i 20 to said surface, including arranging said forward faces at substantially 30 1 20 to i i i

Claims

1. THE METHOD OF PREPARING A DURABLE ELASTOMERIC SURFACE FOR RECEIVING ABRASIVE MATERIAL FALLING THEREON HAVING WEAR RESISTANCE ENHANCED BYY CONTROL OF THE ANGLE OF IMPACT OF SAID MATERIAL THEREON, WHICH SURFACE HAS LOWER WEAR RESISTANCE THAN CONVENTIONAL HARDENED MATERIALS FOR A RANGE OF ANGLES BETWEEN GRAZING AND PERPENDICULAR IMPACT, COMPRISING THE STEPS OF OBSERVING FOR A PARTICULAR MATERIAL FLOW AND SURFACE MOTION IN AN INSTALLATION A CHARACTERISTIC ANGLE OF IMPACT OF A PREDOMINANT PORTION OF SAID MATERIAL UPON SAID SURFACE GENERALLY, SELECTING A SET OF WEAR RESISTANT RESILIENT ELEMENTS HAVING LIKE FORWARD AND AFTER FACES MEETING ASYMMETRICALLY A RIDGED VERTEX, THE RESPECTIVE FORWARD AND AFTER FACES MAKING DIFFERING ANGLES TO TTHE PERPENDICULAR TO SAID SURFACE, SECURING TO SAID SURFACE SAID ELEMENTS IN MUTALLY PARALLEL RELATION ORIENTED TRANSVERSELY TO THE LINEAR MOTION OF THE SURFACE WHEN MOVING, AND TO THE DIRECTION OF IMPACT OF MATERIAL WHEN FIXEDLY INCLINED, TO EFFECT RELATIVE MOTION BETWEEN THE ELEMENTS ARRANGED ON SAID SURFACE AND MOTION OF SAID MATERIAL FALLING THEREON TO CAUSE SAID CHARACTERISTIC ANGLE TO LIE SUBSTANTIALLY WITHIN 20 DEGREES OF SAID PERPENDICULAR TO SAID FORWARD FACES.

2. The method of claim 1, said characteristic angle being approximately 45* from said surface generally, said after faces then being secured at an angle to the surface between 40* and 50*, to cause said material to stike said after faces at a grazing incidence.

3. The method of claim 1 for a said characteristic angle of 45* including securing said forward faces at substantially 45* + or - 20* from the surface and within 20* of perpendicular to said characteristic angle of impact.

4. The method of claim 3 including selecting and orienting elements with said after faces within 5* of said angle.

5. The method of claim 1, said observed characteristic angle being at substantially 30* + or - 20* to said surface including arranging said forward faces at substantially 60* + or - 20* to said surface.

6. The method of claim 5 wherein said after faces are arranged within 5* of said angle.

7. The method of claim 1 said observed angle being at substantially 60* + or - 20* to said surface, including arranging said forward faces at substantially 30* + or - 20* to said surface.