This invention relates to clamps and more specifically to clamping devices for securing skirts to skirt plates in position along the edge zones of a conveyor belt. BACKGROUND OF THE INVENTION

It is well-known, particularly with so-called volume conveyor belts in mining, to provide upright wear plates above the usually-upturned side strips of the belt. Such plates act as guides or doctors to contain the flow of, for example, coal which is being conveyed. The wear plates terminate a short distance above the belt and, to counter the Inevitable migration of smaller coal particles, it is also known to provide outer skirt plates which are mounted on the wear plates and carry usually resilient skirts to more-or-less engage the (moving) conveyor belt near Its outer edges. Particularly in cases where high volume flow is not required and/or when the material conveyed is not very abrasive, wear plates may not be necessary and all the necessary containment can be effected by skirt plates and skirts. One problem associated with conveyor belt skirts which, acting almost as scrapers, require periodic adjustment and/or replacement, lies in the difficulty of removable attachment to the skirt plates. Various clamping systems have been employed, but none has been very satisfactory for reasons Including high cost, complexity and the Inclusion of separable parts such as wedges which, if not tethered, can readily be lost in the often dimly-lit and usually hazardous environment of a mine gallery. OBJECTS AND SUMMARY OF THE INVENTION

It is an object of the present invention to provide Improved clamping devices for use in, for example, securing skirts to skirt plates along the edge zones of a conveyor belt. According to the present invention there is provided a clamp comprising: a clamp body further comprising a waist portion and two lugs, a pin extending between the two lugs; and a locking member further comprising a plate in which is formed a central slot defining at least one ramp surface; the pin passing through the slot. BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings in which:

„-_ Figure 1 1s a half sectional view of a conveyor belt system incorporating wear plates and also skirt plates and skirts clamped 1n accordance with the Invention;

Figure 2 is a fragmentary view on a larger scale, of the system shown in Figure 1 ;

Figure 3 1s a side elevation of a clamp; Figure 4 is a plan view of one type of clamp plate; Figure 5 is a side elevation, partially sectioned of a clamp as used in a right angle relation to a conveyor belt; Figure 6 is a side elevation, partially sectioned, of a clamp used vertically with a conveyor belt;

Figures 7 and 8 show a clamp 1n a released and clamped position; Figures 9 and 10 show two styles of closed loop cotters; and Figure 11 shows an end view of a one piece clamp plate. BEST MODE AND OTHER EMBODIMENTS OF THE INVENTION

A clamp of the present invention may be used in a variety of applications. For example, referring to Figure 1 of the drawings, a conveyor belt 10 is of conventional trough-section form having upturned side zones 11 extending outwardly from a generally flat central zone 12. Central rollers 13 support zone 12 of the belt, and outer Idler rollers 14 support the zones 11. Mounted on a frame extending along the conveyor belt, are upright wear plates 15 of steel which terminate at their lower ends in welded beads 16 spaced a short distance above the adjacent belt zone 11. A profiled steel skirt plate 17 is bolted (at 18) to each wear plate 15 at intervals along Its length, to lie at right angles to the adjacent zone 11 of the belt, and a robust rubber skirt 19 1s clamped to the plate 17 by a series of clamping devices 20 according to the present invention.

As more clearly Illustrated 1n Figures 2 and 3, a clamping device 20 includes a generally cylindrical body member 21 comprising a circular waisted base 22 and a pair of lugs 23 which extend upwardly from and continue the outer cylindrical form of the base. The member 21 is dimensioned so that the base enters one of a series of open-ended channel-shaped runners 24, of standard section if desired, welded intermittently along the skirt plate 17 with opposed, inwardly extending flanges on the channel walls which enter the waist 22A. A pin 25 is-, secured between the spaced lugs 23, and an elongate locking member or captive cotter 26 according to the invention is attached by means of the

pin 25 which passes through central opening 27 in the member 26; the attachment 1s permanent until such time as the pin 25 may be intentionally extracted.

As best shown 1n Figure 3, the member 26 defines a closed uninterrupted loop and is formed as an elongate steel plate having a central opening 27 shaped to provide, in conjunction with the lower elongate face 28 of the member, at least one ramp-Uke surface 29 for engagement with the pin 25. As shown in Figures 9 and 10 each member 126 may have two ramp like surfaces 29, 129. With reference to Figure 10, locking member 126 has a ramp-like surface 129 formed with a series of shallow recesses or undulations to minimise the danger of disengagement with the pin 25.

The other component of the device 20 is clamp plate 30 which 1s Illustrated also in Figures 4 and 11. In the example of Figure 4 and Figure 2, the rectangular plate 30 is formed of steel, with a circular through-opening 31 and has welded at one end an abutment bar 32 and at the other end an abutment 33 In the form of a length of angle Iron. In the example of Figure 11, the abutment surfaces are integrally formed and not welded on. As shown in Figure 5, where the clamp 20 Is used with a skirt which is perpendicular to a conveyor surface, the base 22 of the body member of each of the number of devices 20 required is passed through the opening or bore 31 in its clamp plate 30, and entered into the appropriate runner 24 and slid along to any required position. Alternatively, the body member 21 is first fitted in the channel and the clamp plate Is then placed over the body member which can pass freely through the opening 31. The rubber skirt 19 is then correctly positioned against the skirt plate 117 (17) and clamped in position as follows: each locking member is shifted from the position A (Figure 5) which has allowed passage through the plate opening 31, to position B and then turned through 90° where the bottom face 128 lies against the clamp plate 30, and the locking plate 26 is hammered or otherwise driven to the position shown in Figure 3. When driven, the ramp face 129 (29) engages the anchored pin 25 to urge the clamp plate and thus its abutments downwardly so that the abutment 32 firmly engages the skirt 19, locking the skirt in position against the plate.

As shown in Figure 6, the clamp 20 may be used in a vertical orientation with the skirt 19 contacting the belt at an _, angle.

The clamping operation is shown in more detail in Figures 7 and 8 Note that the locking member 26 comprises a closed loop having a centra opening 150 which defines two inner ramped surfaces 151, 152. The widt W of the locking member 1s narrow enough to pass through the bore 31 of whatever type or style of clamp plate is used. The central opening 150 of the locking member also may include a widened end 153 to facilitate rotating and positioning the member when the pin 25 1s located through that end. Note that with the clamp plate 30 shown in Figures 7 and 8, the abutment 140 1s Integral and bent about 90° with respect to the portion of the clamp plate against which the locking member 26 bears. Figures 9 and 10 show two styles of locking member 126. Both include a diagonal central opening 150 which defines two ramp surfaces 29, 129 and an enlarged end 151 of the opening 150. One corner 152 is rounded near the enlarged end 151. This feature allows the locking member 126 to pivot more easily.

Figure 11 shows a cross-section of a clamping plate 30 formed Integrally from a single steel plate. The plate 30 further comprises a flat portion 160 against which an outer surface of a locking pin bears. The flat portion 160 has a bone 31 through which may pass through both the body member 21 of the device 20 and the locking member 26. One end of the plate 30 is an abutment 161 which is bent about 90° with respect to the flat portion 160. The other end 162 abuts the skirt and may hav a variety of configurations. In the example shown, the skirt clamping abutment 162 is roughly L-shaped in cross-section and is formed at the end of a ramp 163 which extends from the flat portion 160 to the skirt clamping abutment 162.

The clamping devices described above, according to the invention, have proved extremely satisfactory in use, not only as regards their clamping function but also as regards ease of use and absence of accidental loss of parts. Further, the devices are of simple, reliable construction and are relatively inexpensive to produce.

Modifications may be made without departing from the scope of the invention. For example, the bar (32) or an equivalent abutment may be welded to the skirt plate rather than to the clamp plate. Also, a broa rib or other abutment may be formed along the skirt and so avoid the requirement for the abutment 33. Such modifications would simplify the (removable) clamping devices. Furthermore, Instead of being of circula section, the body members (21) may be of square or other rectangular

section, to pass through square or like openings (31) in the plates 30.

In this case, the locking member (29/129) could not swivel 360° as 1n the above examples, but the square-section member (21) would have the advantage of not requiring the milling of a full recess (22A) and, indeed, a shoulder may suffice for engagement with the flanges of the channel-shaped runners 24.

INDUSTRIAL APPLICATION

The invention has many industrial applications where metal parts must be removably clamped together. Two concrete examples are illustrated in Figures 5 and 6, for example, with respect to conveyor belt skirt clamping.