GB2375103A

GB2375103A - Individually Replaceable Wear Plate

Info

Publication number: GB2375103A
Application number: GB0110761A
Authority: GB
Inventors: Alan Wood
Original assignee: CHAPMANS AGRICULTURAL Ltd
Current assignee: CHAPMANS AGRICULTURAL Ltd
Priority date: 2001-05-02
Filing date: 2001-05-02
Publication date: 2002-11-06
Also published as: GB0110761D0

Abstract

A wear plate 29 with wearing surface 28 and inclined connecting part 14 which engages an aperture 36 of a base plate 32 welded or otherwise fixed to a chute or similar. The wear plate 29 is locked into position by plugs, preferably of nylon which are inserted into holes 18 and engage slots 48 in the base plate 32. Wear plates 29 can be replaced individually without rear access after drilling out the plugs. The gap between adjacent wear plates 29 is slightly greater than the thicker of the wear plate 29 and the connector 14.

Description

WEAR PLATE AND ASSEMBLY The present invention relates to wear plates.

Wear plates are known for the purpose of protecting machinery, delivery chutes and other. equipment from wear.

Such wear often occurs through contact with material, such as masonry or other mining/quarrying products, that the machinery etc is processing. Wear plates are sacrificial components, adapted to be releasably connected to the equipment where wear is likely to take place. In delivery chutes, this is often the entire surface and therefore it is desirable that wear plates should be simple and inexpensive.

In chutes, wear plates need to be reasonably closely spaced. If they are separated from one another too much, material can get between them. This can have several undesirable effects. Wear can be occasioned on the base substrate intended to be protected. Material can progressively be jammed between plates, or between a plate and its base, perhaps lifting and dislodging the plate or rendering it difficult to remove.

Wear plates need to be easily replaceable, so that machinery down time is minimised. However, locking devices accessible from the wear surface side are obviously potentially subject to wear themselves and may be rendered inoperative. On the other hand, such devices being accessible only from the side of the substrate not subject to wear is often inconvenient.

Wear plates also need to be replaceable individually. US-A-6164863 and others before it disclose

wear plates which interlock with one another and, certainly, they form a continuous wear surface. But to change one may often require many others to be disconnected first. This leads to long down times, and also to difficult calculations and decisions on the part of the operators. That is to say, decisions about whether partially, but not completely, worn plates should be discarded or returned to their position when they are removed to give access to a plate that does require replacement.

US-A-5241765 discloses an arrangement in which a channelled wear plate slides over T-shaped elements or dovetails and a keeper is resiliently pressed into a slot to prevent sliding of the wear plate. Such an arrangement suffers the problem mentioned above of either requiring a large separation between adjacent plates or many plates needing to be removed to get at particular ones.

US-A-566748 discloses a wear cap having tabs inclined on the cap at a common angle and a rotatable lock having a rigid hub to stop the tabs from exiting corresponding inclined ledges in a base substrate.

US-A-5588768 discloses a wear plate having a connector comprising a lip welded to the wear plate and adapted to engage a tongue of a base plate, a keeper being inserted through the base plate for attachment to the wear plate to stop the lip and tongue disengaging.

It is an object of the present invention to provide a wear plate and base therefor which is simple to construct and easy to employ.

In accordance with the present invention, there is provided an assembly of a wear plate and base therefor, wherein the wear plate comprises :- a) a plate having a wear surface; b) a connector on an opposing plate connector surface of the plate; and b) a plate retention device, and wherein the base comprises :- a) a connector surface having a connector socket corresponding with, and for reception of, said connector; and c) a base retention device, wherein the plate and base are engaged with one another by movement towards one another in a direction inclined with respect to said surfaces, and said connector and socket have substantially the same constant cross-section along said direction from a disengaged position of the plate and base to an engaged position in which said connector surfaces of the plate and base are mating and in which said retention devices can be implemented to inhibit movement of the plate and base with respect to one another in the plane of said mating surfaces, and wherein said retention devices comprise :- a) corresponding apertures through the wear plate and in the base whose axes lie at an acute retention angle to said direction and an acute base angle to said plane; and

b) a plug adapted to be driven into said apertures when the plate has been engaged with said base.

Said retention angle is preferably about 450 to said direction. Said base angle is preferably substantially perpendicular to said plane.

Said plug may be nylon or like polymeric material.

Said connector is preferably annular and welded to said plate around the periphery of its bore.

Preferably the bore of the connector, before welding to the plate, has an axis which is substantially normal to the connector surface of the plate.

By this means welding of the connector and the plate together is substantially confined to beneath said connector surface, with respect to the wear surface, so that substantially the entire depth of the wear plate is available for wear without changing the strength of connection between the connector and the plate.

In use, gravity is employed as the main element holding the wear plate in place and, as such, the present invention finds its most suitable application in situations where the base maintains a constant orientation with respect to gravity.

Thus, in use, the base is arranged so that the connector is inclined downwardley with respect to gravity and so that, when engaged with the socket, it slides down the socket drawing the wear plate towards and into facing contact with the base plate.

In chutes, where the present invention finds its

particular, but not exclusive, application, material transported down the chute will contact the wear plate in a direction which urges the wear plate into closer contact with the base plate. In many instances further retention of the wear plate to the base plate is unnecessary, but even in chutes there will be flatter sections, for instance, where some additional protection against dislodging of the wear plate is required.

Moreover, other applications may demand a more secure arrangement. In these cases, the nylon plug driven into said retention device apertures, along their axes lying substantially normal to the plate surfaces, is generally found adequate. Although such plugs may not prevent axial movement of the plates (axial with respect to the plugs, that is) the angle of the connector and socket demands a lateral movement of the plates with respect to the plugs, which would tend to exert a shear force on them. The plugs can resist this force in most circumstances.

However, they are easily removed by drilling, for instance, when it is desired to change a wear plate.

By virtue of the inclination of the connector and socket, gravity holds the wear plates in place, aided by the retention device. But, at the same time, and depending on the precise angle of inclination, the separation between adjacent plates (on a surface protected by a series of wear plates) can be as little as about the thickness of the connector or wear plate. This is because that separation is all that is needed to enable an individual plate to be removed without interfering with adjacent plates. When the nylon plugs are drilled out, a plate can be levered out, the connector riding up the socket at the inclined angle of

the connector and socket. Thus, the top edge of an adjacent plate needs to be separated transversely from the bottom edge of the plate to be removed only by an amount approximately equal to the thickness of the thinner of the connector or plate divided by the tangent

of the angle of inclination of the connector and socket.

I The angle of inclination of the connector and socket is preferably about 45 . In this event, the separation between adjacent plates need only be equal to, or greater than the thickness of the connector or wear plate, whichever is thinner.

The apertures in the base preferably comprise notches, said apertures being disposed in said wear plate and base on the acute angle side of the connector.

Preferably, there are two of said apertures, one on either side of the line generated by the intersection of normals from said connector and the wear plate connector surface.

The invention is further described hereinafter, by way of example, with reference to the accompanying drawings, in which :- Figures la and Ib are a side view and plan view of a wear plate in accordance with the present invention ; Figures 2a and 2b are a plan view and side section (along the lines B-B) in Figure 2a of a base plate in accordance with the present invention; Figures 3a and 3b are a plan view and side view of a connector for use in the wear plate of Figure 1; and Figure 4 is a side section through an assembly in accordance with the present invention.

With reference to the drawings, a wear plate 10 comprises a simple plate 12 of rectangular shape, cut from a sheet of steel. To the plate 12 is welded an annular connector 14. The plate 12 is provided with two apertures 18 in the form of drillings through the plate.

With reference to Figure 3a and b, the connector 14 is likewise cut from a steel plate, possibly of the same thickness as the plate 12. The sides 20 of the connector 14 are inclined with respect to its end face 21 by an angle 0 equal to 450. Along an axis X-X through the connector 14 parallel the inclined sides 20 of the connector 14, the connector has a round cross-section.

However, at its base, it is provided with a key tongue 16, which nevertheless, has sides parallel the side 20 of the connector 14. In other words, along its length, parallel its axis X-X, the connector 14 has a constant cross-section. Parallel an axis Y-Y, which is normal to the end face 21 of the connector 14, a round bore 22 is formed through the connector 14. The bore 22 is employed to weld the connector to a plate connector surface 24 of the plate 12. A weld bead 26 almost fills the bore 22, securely fastening the connector 14 to the plate 12.

The plate 12 is provided with a wear surface 28 opposite the plate connector surface 24. The wear surface 28 may be provided with a hard coating to reduce the wear rate of the wear plate 10.

Turning to Figures 2a and b, a base 30 is shown which likewise comprises a simple plate 32 cut from a sheet of steel. The plate 32 can be any convenient shape, but it is shown scalloped at 34 to facilitate welding to a substrate surface to be protected from wear.

A central connector socket 36 is formed in the base plate

32 which is sized to match the connector 14, and so that the connector 14 is a close sliding fit in the socket 36.

Thus, the socket 36 has inclined side walls 40 having a notch 38 adapted to receive the key 16 of the connector 14. The sides 40 are parallel an axis X'-X', the axis X'-X'being inclined with respect to the surface 42 of the base 30 by the same angle 0 equal to 450.

The base plate 30 has a base connector surface 42 and in that surface is provided notches 48 in corresponding locations with respect to the socket 36 as are the apertures 18 with respect to the connector 14 of the wear plate 10.

Thus, in use, a base plate 30 is welded to a substrate surface (not shown). A wear plate 10 is engaged with a base plate 30 by engagement of the connector 14 with the socket 36. Although the angles of the connector and socket are such that no rotation about the axis Y-Y of the plate 12 with respect to the base 30 would be possible (once the wear plate 10 is engaged with the base plate 30) whether or not the key 16 was provided, nevertheless, the key 16 engaged with the notch 38 precisely locates the plates together. Consequently, the apertures 18 are aligned with the notches 48. In this position, the connector surface 24 of the wear plate 10 is in mating contact with the connector surface 42 of the base plate 30.

To retain the wear plate in position, nylon plugs are driven into the apertures 18 so that they pass through the wear plate 10 and enter the notches 48. Such plugs (not shown) then prevent any movement of a wear plate 10 upwardly in the drawings and therefore prevent the connector 14 from being lifted out of the socket 36.

Indeed, in order to ensure no such movement is possible, there needs to be an acute retention angle os between lines of the apertures 18 and connector 14. With the connector being at 450 to the base, the aperture 18 and notches 43 can subtend a base angle with the base 30 of 90 to achieve the requisite acute retention angle, which in this event is also 450. I Although shown as notches 48, they could equally comprise apertures corresponding with the apertures 18.

However, notches are easier to manufacture with a laser cutting device that cuts out the entire plate 32 from a base sheet (not shown)-a separate drilling operation is not required.

However, as notches in the base, they must be below the socket 30 and connector 14. Alternatively, they could be formed as notches in the wear plate 12, but in that event would need to be above the socket 30 and connector 14 to perform their function. This arrangement is not preferred because notches in the top edge of the wear plate would expose the plugs to potentially excessive wear. This could undermine the locking provided by them. Such a situation is unlikely in the preferred arrangement (as shown) in which the plugs have all-round protection in the apertures 18. The top surface of the plugs will initially have preferential wear, compared with the surface 28, but probably not subsequently, once its surface is shrouded by the edges of the apertures 18. This is particularly the case where abrasion is primarily in a direction parallel the surface 28, which is normally the case.

Particularly when notches 48 are employed, it is desirable that the apertures 18 are evenly spaced on

either side of a line 25 generated in the surface 24 by normals 23 from the connector 14. This provides even triangulation with the connector 14 and inhibits rotation of the wear plate 10.

In use, it is the plate 12 which gradually wears away. Thus, the welding of the connector 14 to the connector surface 24 of the plate 12 ensures that wear of the plate 12 does not undermine the strength of connection between the connector 14 and the plate 12.

Such would be the case if the connector 14 penetrated the plate 12 and was received in a window therein. Also, welding the connector 14 to the plate 12 about an internal peripheral weld bead 26 means that the external side face 20 of the connector 14 is clean and the angles it makes with the connector surface 24 are sharp.

Consequently there is nothing to prevent close intimate contact between the connector surfaces 24,42 of the wear and base plates 10,30.

Adjacent wear plates to the plate 10 can be butted close to side edges 27 because, to release a single plate, only in the direction of line 25 is relative movement between adjacent plates needed. Turning to

Figure 4, the minimum separation d1 needed between adjacent ends 29 of plates 10, lOa in order to ensure that one plate (eg 10) can be removed without having to disturb adjacent plate lOa, is given by d1 = t/tan E) or titan 8, whichever is smaller where t = thickness of the connector 14 where ti = thickness of the wear plate 12 When t=t1, and 8 = 450, then d = t = t1

Claims

1. An assembly of a wear plate and base therefor, wherein the wear plate comprises :- a) a plate having a wear surface; b) a connector on an opposing plate connector surface of the plate ; and c) a plate retention device, and wherein the base comprises :- a) a base connector surface having a connector socket corresponding with, and for reception of, said connector; and b) a corresponding base retention device, wherein the plate and base are engaged with one another by movement towards one another in a direction inclined with respect to said surfaces, and said connector and socket have substantially the same constant cross-section along said direction from a disengaged position of the plate and the base to an engaged position in which the said connector surfaces of the plate and base are mating and in which said retention devices can be implemented to inhibit movement of the plate and base with respect to one another in the plane of said mating surfaces; and wherein said retention devices comprise :- a) corresponding apertures through the wear plate and in the base at a retention angle to said direction and a base angle to said plane; and b) a plug adapted to be driven into said

apertures when the plate has been engaged with said base.

2. A assembly as claimed in claim 1, in which said base comprises a base plate.

3. An assembly as claimed in claim 2, in which said apertures in the base comprise a notch in the periphery of said base plate.

4. An assembly as claimed in claim 1,2 or 3, in which said plug is nylon or like polymeric material.

S. An assembly as claimed in any preceding claim, in which there are two each of said corresponding apertures in the wear plate and base.

6. An assembly as claimed in any preceding claim, in which said connector is annular and welded to said plate around the periphery of its bore.

7. An assembly as claimed in claim 6, in which the bore of the connector, before welding to said plate, has an axis which is substantially normal to the connector surface of the plate.

8. An assembly as claimed in any preceding claim, in which said direction subtends an angle of about 45 with respect to the plane of said mating surfaces.

9. An assembly as claimed in any preceding claim, in which said connector and socket are provided with a corresponding key and slot respectively to rotationally lock the plate with respect to the base.

10. An assembly as claimed in any preceding claim, in which said retention angle is about 45 .

11. An assembly as claimed in any preceding claim, in which said base angle is about 90 .

12. An assembly as claimed in any preceding claim, wherein there is only a single connector centrally disposed on the wear plate.

13. A wear plate for an assembly as claimed in any preceding claim.

14. A substrate to which a plurality of bases of assemblies as claimed in claim any of claims 1 to 12 is fixed and to which wear plates as claimed in claim 13 are replaceably fixed.

15. A substrate as claimed in claim 14 comprising a chute.

16. A substrate as claimed in claim 14 or 15, in which separation between adjacent wear plates in the direction of a line generated in the wear plate plane by normals to the wear plate plane from said connector is about equal to the thickness of the thinner of the connector and wear plate divided by the tangent of the angle of inclination of the connector with respect to said plane.