Clips for attaching staples for joining conveyor belt ends and clip-staple assemblies
The present invention relates to clips intended for attaching conveyor belt ends with staples for joining conveyor belt ends. In addition, the invention relates to a clip-staple assembly associating both elements prior to the positioning of staples on the conveyor belt ends.
Joining staples for conveyor belts, belts and similar products composed of a top plate and a lower plate, both said plates being connected at one end by one or several narrower parts called knuckles are known, with said staples being mounted in two series each compassing one end of the conveyor belt between the top plates and the lower plates of the staples in each series, the same operation being carried out again on the other end of the conveyor belt while shifting the knuckles of the second series of staples with respect to those of the first series, so that the knuckles of the second series are engaged between the knuckles of the first series. A connecting and articulating rod is then engaged into one knuckle of a series of staples and then into one knuckle of the other series of staples and so on, thus making the equivalent of a hinge.
As regards the attaching of staples at conveyor belt ends which they hold between top plate/lower plate couples, various means are used, with two means being

the most common ones when considering the development of the related technology.
The most common staple attaching means consists in U-shaped clips made of round wire. Such clips include a back composed of a rectilinear round wire part extended at both ends by acute branches made of the same wire and bent at right angles with respect to the back. The spikes of the round wire branches are obtained by machining, i.e. milling or grinding.
A second known means for attaching staples is composed of claws extending the top plate of the staple downwards.
The clips made of U-shaped metal wire are inserted into holes provided in the top plate of the staples. The acute branches go through the end of the conveyor belt inserted between the top plate and the lower plate of the staple. The claws extending the top plate of the staple are directly inserted into the ends of the conveyor belt inserted between the two plates.
Initially, the acute branches of the clips, when inserted through the thickness of the conveyor belt end, would meet corresponding holes provided in the other plate of the staple, then would go through such holes and be bent towards the outside of the lower plate of the staple. Similarly, the claws inserted along a similar path would also be bent towards the outside of the lower plate. This bend was made using

an appropriately shaped matrix positioned under the lower plate.
The drawbacks of round wire clips lies in the fact that in order to have an excellent bending strength, it is necessary to increase the diameter thus causing difficulties resulting from the induced over-thickness which cannot be totally accommodated in a recess of the top plate of the staple which created problems with the scrapers. In addition, the clips made of round wire include branches, the end parts and spikes of which are made by grinding or milling and have mechanical properties which do not differentiate them from the rest of the clips, which means the back of the clips and the body of the branches. For bending the lower parts of the branches, steel wires are generally chosen, the mechanilcal properties of hardness and bending strength of which are mean, with a view to prevent breaking during the bending operations. Such properties are in contradiction with those which are required for the spikes of the branches to go without any difficulty and any deviation through the reinforcing frames of the elastomer material of the conveyor belts.
It should be noted that, on the clip-staple assembly of the prior art patent EP 0 464 399, that the staple is provided, in the top portion thereof, with a recess making it possible to accommodate most of the thickness of the back of the clip. However, a small over-thickness which is liable to be hit by the scrapers

remains. If it ig desired to increase the diameter of the round wire clip to obtain a better strength therefrom, the problem becomes impossible to solve since it would be necessary to increase the thickness of the top plate of the staple which can also be hit by the scrapers.
It should be understood that the clips made of round wire cannot be perfected because of their basic design.
The present invention aims at providing new improved clips which totally eliminate such drawbacks and which further provide new advantages as regards the ease of implementation of new clip-staple systems as well as the robustness in use of such new clips with, in addition, a versatility for positioning the claws of the clip which make it possible to create particular positioning, making it possible for the clips which have been mounted, to resist constraints exerted in various directions depending on the utilization of the conveyor belt and more particularly in the case of troughing, for the conveying of bulk products.
These goals are reached with a clip for joining staples for conveyor belts including a top portion forming the back and claws which are substantially perpendicular to the top portion forming the back intended to go through holes correspondingly provided in the top plate of a joining staple of conveyor belts of the type having a U-shaped profile, including a top plate, a lower plate and one or several knuckles joining the top plate and

the lower plate, characterised in that the top portion forming the back is composed of a sheet metal plate forming the back and by two or more claws which are substantially perpendicular to the sheet metal plate forming the back and which are connected thereto.
In a first embodiment, the claws are in one piece with the sheet metal plate forming the back, and provide extensions of said plate forming the back, which are perpendicular thereto and connected by a bending of the sheet metal of the plate forming the back.
In another embodiment, the claws of the clip are made of sheet metal parts or wire parts welded on the lower face on the sheet metal plate forming the back of the clip.
In both embodiments, the claws advantageously have a rectangular section, the spike on the claw only being an exception to such rectangular shape of the section. The orientation of the larger side of the rectangular section is advantageously oriented longitudinally with respect to the clip, but other orientations are possible as these will be explained in the following as regards preferred embodiments. In alternative solutions, the rectangular section can be replaced by a section having the shape of a trapeze, a half pipe or a rectangle having rounded or chamfered corners or even by a circular section in some embodiments.
In certain cases, the larger sides of the rectangular section of the claws are symmetrical with respect to

the longitudinal axis of the clip. In the case where some larger sides of the rectangular sections are transversally oriented it can be advantageous for one or several claws to be wrapped around the longitudinal axis of the clip.
The larger sides of the claws section can also have various orientations, with some larger sides being oriented along an angle between these two orientations.
To obtain a better strength of the bending separating the top plate part from the corresponding claw, a re¬entrant reinforcing rib embossed in the plate is provided in the bending of the sheet metal, in the top portion of the claws which is close to the bend and extending into the bend, and in the part of the plate forming the back which is close to the bend, such rib being provided in the longitudinal direction of the claws, substantially in the middle of the claws width.
To have spikes with a better hardness and bending strength, the spikes on the claws can be hammer-hardened during the manufacture thereof. A less intense hammer-hardening can also be provided on the stem part of the claws. As the back and the claws can be made in sheet metal according to the invention, a mean quality metal can be used, with the stem and spike parts of the claws can also be hammer-hardened during the manufacturing of the clip on the press, by carrying out cutting, bending, embossing and punching operations.

In order to make the provisional assembly of a clip and a staple easier, prior to the final attaching at the end of the belt conveyor, the present invention provides that at least some of the claws have a shallow horizontal groove on their external sides, embossed in the stem of the claw and the height of which is slightly above the thickness of the sheet metal of the top pilate of the attaching staple, which the clip is intended for, and being located close to the leader of the spike part which shows an oblique plane area with respect to the general plane of the claw, said plane area starting from the very end of the claw and ending with a straight line close to the lower edge of the groove, the top edge of the groove being advantageously chamfered and the bottoms of the grooves of both opposite claws having a spacing which corresponds to the spacing of the edges located on the outermost side, of the holes in the top plate of the joining staples which the clip is intended for.
It is also possible to provide for grooves on the innermost sides of the claws, the groove in each considered claw being horizontal and shallow and embossed in the stem of the claw with a height which is slightly above the thickness of the metal sheet of the top plate of the joining staple, which the clip is intended for, and being located close to the leader of the spike part which has an oblique plane area with respect to the general plane of the claw, said plane area starting from the very end of the claw and ending

with a straight line close to the lower edge of the groove with the top edge of the groove being advantageously chamfered and the bottoms of the grooves of two opposite claws having a spacing which corresponds to the spacing of the edges on the innermost side, on the holes on the top plate of the joining staple which the clip is intended for.
It is thus possible to snap-fit the holes on the edges of the holes of the top plate on the staples, the clip-staple assembly being ready for the engagement of the claws using a hammer and a hydraulic punch or a pneumatic punch. The chamfer provided on the top edge of the groove aims at facilitating the sliding on the edge of the hole, since a right angle edge would tend to catch the edge of the hole upon the engagement. Similarly, the oblique area of the spike mentioned hereabove allows the engagement of the claw into the hole while causing a resilient motion of the claw stem, such motion being reverted upon the snap-fitting of the groove with the edge of the hole of the top plate of the staple.
Thanks to the design of the clip, the orientations of the claws can be selected as necessary, depending on the constraints provided for the joining. Several preferred embodiments of the invention, which are not limitative, will now be described while referring to the drawing, the figures of which are summarized hereinunder.

Figure 1 is a aide view, partially in section, of a staple and a clip made of steel wire of the prior art according to patent EP 0 464 399.
Figure 2 is a perspective view of one embodiment of the clip according to the invention.
Figure 3 is a perspective view of an embodiment of the clip according to the invention.
Figure 4 is a perspective view of a clip similar to that of Figure 2, but including snapping grooves.
Figure 5 is a perspective view of a clip according to Figure 4, ready to be inserted into the corresponding holes of the top plate of the staple.
Figure 6 is a perspective view showing a segment of a clip according to Figure 4 and a fragment of a staple, with the clip being snap-fitted using the grooves of its claws in the edges of the holes of the top plate of the staple.
Figure 7 is a perspective view showing a staple mounted on one end of a conveyor belt, the top portion forming the back of the clip being buried in a recess of the top plate of the staple, and a part of the bends of the claws being visible.
Figure 8 shows another embodiment of the clip and a corresponding staple.

Figure 9 shows a clip according to Figure 8 mounted on a corresponding staple.
Several preferred embodiments, which are not limitative, showing clips according to the invention will now be described while referring to the figures of the drawing.
Figure 1 is a drawing of a clip-staple system of the prior art according to patent EP 0 464 3 99 (Figure 8) mounted on one end of the conveyor belt and showing a clip made of round wire 12, a staple 1 including a top plate showing a recess 11, a lower plate 3 including a bridge 14, holes 10, 13 and 15 being provided for the passage of the branches of the wire clip having two generally U-shaped branches.
Figure 2 shows an embodiment of the clip according to
the invention. It should be noted that the top portion forming the back 1, six claws 2, the bends 3 connecting the top portion forming the back 1 to the claws 2, the re-entrant ribs 4 are shown from the outside and the re-entrant parts 4', the spikes 6. As will be easily understood by the person skilled in the art and in the machining of metals, this part can be obtained by a machining with a press, by cutting, punching and embossing operations. When carrying out these operations, the spikes and if need be these stems 7 of the claws can easily be punched so that they can have a hardness and a bending strength higher than those of the basic metal. It should also be understood that the

very design of the clip makes it possible to provide on the same part forming the back a number of claws greater than 2, which can even reach, if so desired, for example 10 claws. The embodiment shown includes 6 claws positioned in the longitudinal direction. It should be noted that such embodiment advantageously provides shifts as regards the positioning of the claws in the transversal direction. Such shifts make it possible to prevent the creation of longitudinal lines showing the breaking in the frame of the end of the conveyor belt, as gone through by the clips and submitted to tractions and jerks in the longitudinal direction. Such possible breaking lines would result from drillings aligned in the longitudinal direction, which would be caused by non-shifted claws in the transversal direction, the drillings being thus too close to each other in the longitudinal direction.
In the following description of the embodiments of the invention, the same references will be used for similar parts of clips and/or staples. Conventionally, the longitudinal direction of the clips or staples is that of the conveyor belt on which the clip and the staple must be mounted, whatever the dimensions of the clips and the staples. Similarly, the transversal direction will be the direction perpendicular to the longitudinal direction, whatever the dimensions of the clips and the staples. On the contrary, the longitudinal direction of the claws will be that of the larger dimension thereof.

Figure 3 shows another embodiment of the clip according to the invention, wherein the stem of the claws have a section which is not strictly rectangular since both external angles 8 and 8' of the section being chamfered. In this case too, this form can be obtained during the manufacture thanks to a coining operation.
Figure 4 shows another embodiment of the clip according to the invention which is similar to that of Figure 2, but wherein grooves 9 provided in the claws can be seen. Such grooves 9 are shallow and they can. be obtained in the course of the manufacture of the clip thanks to a coining operation. The grooves 9 include a top edge 9', a bottom 9" and a lower edge 9"', The lower edge 9"' is close to an oblique part 6' of the spike 6 which extends from the very spike up to the vicinity of the lower edge 9"' of the groove 9,
Figure 5 shows the clip according to the invention of Figure 4, ready to be inserted into the through holes 10 provided in the top plate 11' of a joining staple 11 of a conveyor belt, such holes having a section adapted to the section of the claws.
Figure 6 shows the clip according to the invention of Figure 5 snap-fitted with the edges 10' of the through holes 10 being engaged in the grooves. Upon the snap-fitting of the grooves in the holes, the oblique part of the spikes 6 of the claws have temporarily deformed the claws elastically by sliding on the edges of the holes, and when the holes 10' meet the grooves the

claws get snap-fitted and return to their original shape.
This makes it possible to show clip-staple assemblies ready to be mounted on the end of the conveyor belt.
It should also be noted that in Figures 4, 5 and 6 that
the top edge 9' of the groove is chamfered. This
chamfer aims at preventing the top edge of the groove
to catch the edge of the hole of the top plate of the
staple when the claws are subsequently pressed at the
end of the conveyor belt, and to allow the smooth
positioning of the claws by pressing on them.
Figure 7 shows a staple mounted on the end of the conveyor belt. It should be noted that the clip according to the invention is almost totally engaged in a recess of the top face of the top plate of the staple. Such a clip which is correctly attached by the multiple staples thereof is protected against the stripping caused by the scrapers upon the operation of the conveyor belt. Something important should be noted here. Thanks to the design of the clip according to the invention in all the embodiments thereof, the top plate can be relatively thin which makes its accommodation in the recess 15 of the top plate of the staple easier, whereas the claws obtained by cutting and bending the sheet metal of the top plate can have a large section by using a rectangular shape or other shape as mentioned above and having dimensions in the transversal section of the claw much higher than those

of the other dimensions which corresponds to the thickness of the top plate. In the case of claws welded on the top portion forming the back, the selection of the cross-section of the claws is obviously open since this series of clip according to the invention also having the advantages of the multiple-claw clip according to the invention, the top portion of which forming the back can have a relatively-thin thickness and be easily buried in the top plate of the claws.
Figure 8 shows another embodiment, a so-called star embodiment, of the clip according to the invention. It should be noted that the orientations of the claws are varied. Such plurality of orientations makes it possible for the positioned staples to behave properly in the case where the conveyor belt is submitted to forces and jerks oriented in various directions more particularly in the case of the traffic of the conveyor belt intended for the treatment of bulk materials.
Figure 9 shows the same staple and the same clip as Figure 8 with the clip being in the final position thereof in the staple.
The invention thus reaches all the initially aimed at goals, i.e. the easy manufacturing using tools well known to the persons skilled in the art, without any cold lap, of a strong multiple-claw clip including a relatively thin back which can be easily accommodated without showing at the top plate of the clip of the

staples. The claws can show hardness and bending strength properties which are different from those of the part forming the back of the clip, without any cold lap after the manufacturing of the clip through working on the press and using a mean quality metal thanks to a different hammer-hardening which can be obtained without any cold lap, and carried out using the tool for manufacturing the clip.
The versatility of the permissible configurations, without leaving the scope of the invention, is particularly remarkable.

CLAIMS
1. A clip for attaching staples for joining conveyor belt ends comprising a top portion forming the back and claws substantially perpendicular to said top portion forming the back and intended to go through corresponding holes in the top plate of a joining staple of conveyor belt ends of the type having a U-shaped profile and including a top plate, a lower plate and one or several knuckles joining the top plate and the lower plate, characterised in that the top plate forming the back (1) is composed of a metal sheet part the configuration of which is adapted to that of an accommodation recess provided in the top plate of a corresponding joining staple, said top portion forming the back (1) bearing, on the periphery thereof, at least two claws (2) and preferably more, such claws being connected to the top portion (1) by composing perpendicular extensions of said plates forming the back, connected by a bend (3) of the metal sheet plate forming the back, said bend including a re-entrant reinforcing rib (4) embossed in the top portion of the claws near the bend (3) and extending in the bend proper (3) and in the area of the top portion (1) close to the bend (3) , the reinforcing rib (4) being provided in the longitudinal direction of the claws (2) approximately in the middle of the width of the claws (2) or the claws (2) being welded together

approximately at the periphery of the metal sheet part composing the top portion (1) of the clip.
2. A clip according to claim 1, characterised in that the spikes (6) of the claws (2) are hammer-hardened during the manufacture thereof and have a hardness and a bending strength above those of the other parts of the claws (2) and that of the plate forming the back (1).
3. A clip according to claim 2, characterised in that the stem part (2') of the claws has been hammer-hardened during the manufacture thereof and has a hardness and a bending strength above those of the plate forming the back (1) but lower than that of the spike (6) .
4. A clip according to any one of the preceding claim,
characterised in that the claws (2) have a rectangular section, with only the spike (6) of the claw (2) being an exception to such a rectangular shape of the
section.
5. A clip according to claim 4, characterised in that
the larger sides of the claws (2) section can have
varied orientations, some larger sides being
transversally oriented, other sides being
longitudinally oriented and other sides again being
oriented along an angle between both these
orientations.

6. A clip according to any one of the preceding claims, characterised in that at least some of the claws have a shallow horizontal groove (9) embossed in the stem (2') of the claw (2) , with a height which is slightly above the thickness of the metal sheet of the top plate of the joining staple which the clip is intended for and being located close to the leader of the spike part which has a plane oblique area (6') with respect to the general plane of the claw, said plane area starting from the extreme spike of the claw and ending with a straight line close to the lower edge (9") of the groove (9) with the top edge of the groove (9) being advantageously chamfered and the bottoms (9'") of the grooves of both opposite claws having a spacing which corresponds to the spacing of the outermost edges of the holes of the top plate of the joining staple which the clip is intended for.
7. A clip according to anyone of the preceding claims except for claim 6, characterised in that at least some of the claws have on their inner sides a shallow horizontal groove embossed in the stem (2') of the claw (2) , with a height which is slightly above the thickness of the metal sheet top plate of the joining staple which the clip is intended for, and being located close to the leader of the spike which has an oblique plane area (6') with respect to the general plane of the claw, said plane area starting from the extreme spike of the claw and ending with a straight line close to the lower edge (9") of the groove (9),

with the top edge of the groove (9) being advantageously chamfered and the bottoms (9"') of the grooves of both opposite claws having a spacing which corresponds to the spacing of the edges located in an 5 innermost position, of the holes in the top plate of the joining staple which the clip is intended for.
8. A clip/staple assembly according to claim 6 or according to claim 7, characterised in that the clip is associated with a joining staple of conveyor belts, the claws (2) of the clip being engaged in the corresponding holes of the top plate (11') of the staple, the grooves (9) of the claws being snap-fitted on the edges of the holes of the top plate of the staple, the spikes (6) of the claws (2) possibly passing under the lower face of the top plate (11') of the staple as a function of the thickness of the metal sheet composing the top plate (11') of the staple and the positioning of the grooves (9) in the lower part of the claws.