Abstract:
A strip of riveted belt fasteners is provided manufactured in a punch press or the like to form multiple belt fasteners at a time with the fasteners each being attached to an end of a conveyor belt by way of a single rivet extending through single apertures in upper and lower plates of each of the fasteners. The small fasteners herein are provided with sufficient strength to be used in abusive hay baler applications while the fasteners must travel about small pulleys, e.g. 3″ to 3.5″ inches in diameter. Further, the installation of this rivet belt fastener in the field is about as simple as driving a nail requiring a portable applicator tool and a hammer. That is, the fasteners can be riveted attached to the belt end by way of a low cost applicator tool that includes recessed hardened anvil surfaces integrally formed in the body thereof to upset initially rivets which are driven through the belt with a separably attached pilot nail. The hollow rivet end flares out against the hardened anvil surfaces of the tool with the surfaces being inclined for curling of the rivet end back up into an enlarged recess in the overlying plate aperture. As the rivet is driven, the belt compresses with the rivet end being upset; and upon removal of the driving force, the belt decompresses to draw the curled, upset rivet end into the plate aperture.

Description:
FIELD OF THE INVENTION 
     The invention relates to a rivet belt fastener which is useful in splicing conveyor belts such as hay baler conveyor belts or the like and, more particularly, to a strip of stamped belt fasteners with each fastener in the strip including upper and lower plates attached to the belt by a single rivet. 
     BACKGROUND OF THE INVENTION 
     Mechanical belt fasteners are widely employed in a variety of belt conveying applications for splicing ends of conveyor belts together. One use of such belt fasteners is to splice conveyor belts for agricultural equipment such as round hay balers and net wrap hay balers. There are hinged fastener systems that have fasteners with upper and lower plates joined by arcuate loops. The plates have apertures therein with respective apertures in the upper and lower plates being aligned so that fastener members, e.g. rivets, staples, can be installed through the apertures and the belt for clamping the plates on the corresponding belt upper and lower surfaces. With the hinged fastener so attached, the loops project beyond the belt end for cooperating with the loops of similar fasteners attached on another belt end to form a passageway through the mating loops for receiving a hinge pin therethrough thereby hingedly connecting the belt ends together. 
     Although the rivet belt fastener of this invention may be made in various sizes and used in various applications, it is particularly useful for agricultural equipment such as hay balers where the splices are made with small belt fasteners. Small size belt fasteners are used to pass around small diameter pulleys e.g. 3 to 3.5 inches in diameter. Currently, one of the more widely used baler belt fasteners is secured with staples rather than rivets to secure the belt fasteners to the belt. A particular problem with these splices is the abusive operating conditions encountered and hence the need for a strong, long lasting splice, which preferably can be easily applied by the farm worker in the field when making repairs or new splices. The staple fastener tools currently in use to secure the staples into the belt are rather expensive and unwieldy for the farmer; and hence there is a need for a less expensive and simpler applicator tool for easy field installation of the belt fastener splice. Thus, there is a need for a new and inexpensive applicator tool for field installation of these small belt fasteners. 
     During operation of the spliced conveyor belts, the fasteners are subject to loads such as due to tension forces which, if sufficiently high, can cause the belt fasteners to fail. The strength required from a fastener to avoid such failures varies to a large extent based on the application involved and thus the belt utilized. Accordingly, with light and medium duty applications such as with conveyors for food and agricultural products, fasteners having strength ratings lower than that used in more heavy-duty applications such as in underground mines and aggregate plants, can be employed. Regardless, it is desirable to have the fastener provide the greatest strength possible for the particular conveyor application with which it is to be utilized without over design thereof such as by having extra large or thick plates and greater numbers of rivets, as this could unnecessarily drive up the costs associated therewith. 
     In addition to keeping the costs of the fastener material down, production costs also have to be controlled so as to provide lowest cost belt fastener possible to the end user without sacrificing performance. The production costs can get to be too expensive depending on how the fasteners are made, such as if they are each individually formed as by a forging process, see, e.g., U.S. Pat. No. 5,553,359 to Herold. 
     In the &#39;359 patent, the individual belt fasteners are connected in a strip by a welded wire and attached to an end of a conveyor belt by a pair of solid rivets or pins that are staked at their ends by pointed punch tools to create enlarged rivet heads. The applicator tool of Herold has to form enlarged heads on both ends of a solid pin and the applicator tool used is both expensive and fairly difficult to use in the field. One problem with this solid rivet fastener is that the enlarged heads project beyond the plane of the fastener plates associated therewith. These projecting heads are subject to frictional forces by engagement with pulleys and belt cleaners and conveyed products and thus tend to abrade and wear away over time. This wearing away of the rivet heads accordingly reduces the strength of the fastener and can lead to premature failure thereof. A further problem relates to use in conveying agricultural products, and more particularly, wrapped bales of hay such as with netting material. In this instance, it is especially important for the fastener to have a smooth, low profile with no projecting portions that could catch or snag on the net wrapping about the bales. As is apparent, the projecting rivet pin ends of the &#39;359 patent would not be desirable for this reason. Accordingly, a hinged rivet fastener with better formed rivet heads would be desirable. 
     The installation of riveted belt fasteners can be done with application tools such the MSRT and SRTA tools provided by applicants&#39; assignee herein which are adapted to drive rivet and nail assemblies, such as disclosed in U.S. Pat. No. 3,990,343, through conveyor belts so as to upset the hollow end of the rivet attached to the nail for riveting the fasteners to the belt end. The tool employs a structural steel channel body mounting hardened bushings raised over the upper surface thereof for receiving the nails of the rivet and nail assemblies when driven. The hollow ends of the rivets are upset and spread outwardly by the enlarged head of the nail and in adjacent annular trough anvil surfaces of the bushings. The bushings also provide positioning for the fasteners by fitting the countersunk rivet apertures in the lower plate of each fastener thereover. Each of the hardened bushings adds significant expense to the tool, e.g. the hardened bushings may represent approximately 35 to 40 percent of the total cost for the tool making the tool expensive for farmers to use on a sporadic basis in the field. Accordingly, a belt fastening system, and more specifically an application tool, that is less expensive would be desirable. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention, a strip of riveted belt fasteners manufactured in a punch press or the like to form multiple belt fasteners at a time with the fasteners each being attached to an end of a conveyor belt by way of a single rivet extending through single apertures in upper and lower plates of each of the fasteners. As the fasteners are preferably joined integrally in a strip as formed by a progressive die stamping process, the fasteners do not have to be individually formed as by forging thus avoiding the increased cost associated therewith. The small fasteners herein are provided with sufficient strength to be used in abusive hay baler applications while the fasteners must travel about small pulleys, e.g. 3″ to 3.5″ inches in diameter. Further, the installation of this rivet belt fastener in the field is about as simple as driving a nail requiring a portable applicator tool and a hammer. That is, the fasteners can be rivet attached to the belt end by way of a low cost applicator tool that includes recessed hardened anvil surfaces integrally formed in the body thereof to upset initially rivets which are driven through the belt with a separably attached pilot nail. The hollow rivet end flares out against the hardened anvil surfaces of the tool with the surfaces being inclined for curling of the rivet end back up into an enlarged recess in the overlying plate aperture. Preferably, the size of the plate recess is coordinated with the tool recess for receiving the enlarged curled head of the rivet to provide for a good set of the rivet end in the recess. 
     In one form of the invention, a strip of riveted hinged fasteners for splicing ends of conveyor belts together is provided with the fasteners being joined together integrally in the strip and formed by a progressive die stamping process. Fasteners of the strip each have a pair of spaced plates connected by arcuate hinge loops which project beyond the belt end when the plates are riveted to the belt. A plurality of rivets each include a shaft and an enlarged head at one end of the shaft with a cylindrical wall portion at the other end for forming an upset head thereat to attach the plates to the belt. A single aperture is formed in each of the plates with the apertures of the plates of each of the fasteners generally being in alignment with each other when pressed against a conveyor belt for receiving the rivet therethrough. Each aperture incudes an enlarged recess to receive respectively the enlarged head and the upset head of the rivet. The present fastener strip provides a low cost, small fastener that has good strength characteristics by way of its single rivet attachment to a belt end. 
     Inclined surfaces extending about respective recesses are provided for receiving the enlarged and upset rivet heads tightly therein. In this manner, the inclined surfaces assist in providing the rivet with a good set in the plate apertures. 
     Preferably, the upset rivet head is seated in the aperture so that it is flush with or recessed below the plane of the associated plate. In this manner, the upset rivet head will not serve as a catching location such as for conveyed products, e.g. net wrapped bales. 
     The riveted belt fastener can be attached to belts which range in thickness, e.g. from 0.125″ to 0.218″ inch. Accordingly, the rivet hinged fasteners herein provide good flexibility in their application on different thicknesses of belts. The present fasteners will have more rivet metal curled for the thin belt than for the thicker belt, but in each instance there is a good curled head on the rivet. 
     In one form, the hinge loops of each of the fasteners include a pair of hinge loops symmetrically oriented about the apertures of the plates to equally share applied loads when the fasteners are riveted to the belt end. 
     Preferably, the plates and loops are of a substantially constant material thickness in cross-section. 
     In one form, the strip is provided in combination with a pilot nail at the cylindrical wall portion of each of the rivets, and an anvil including countersunk recesses each having a rivet end curling surface that are inclined to guide the rivet cylindrical wall portion for being curled up to be set in the overlying plate aperture. 
     Preferably, the plates of each fastener have a predetermined width and the apertures are generally circular in shape and have a diameter that is approximately half the width of the plate in which it is formed. In this manner, the size of the apertures is maximized relative to the amount of plate material thereabout so that the rivet heads can be larger for increasing the holding power of the riveted fasteners. 
     In another aspect of the invention, an easy to use applicator tool for riveting belt fasteners onto belt ends is provided and includes a body of high strength metal material with an upper support surface for resting the lower apertured plates of the fasteners thereon. Recesses are provided in the support surface with the apertures of the lower plates placed in overlying relation to the recesses for riveting of the fasteners onto a belt end. Inclined anvil surfaces of the recesses are hardened for resisting high impact forces as the rivets are driven through the belt end by a hammer and for causing an end of the rivet driven thereagainst to be upset and guided into the overlying lower plate aperture for setting therein. Thus, field installation can be made with this easy-to-use, inexpensive applicator tool and a hammer. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a strip of hinged fasteners that are integrally joined together in accordance with the present invention; 
     FIG. 2 is a plan view of the strip of fasteners of FIG. 1 showing a pair of arcuate hinge loops symmetrically oriented about a plate aperture of each fastener; 
     FIG. 3 is a plan view of the strip of fasteners formed by a progressive die stamping process before being bent and folded over into the form shown in FIG. 1; 
     FIG. 4 is a side elevational view of the strip of fasteners as shown in FIG. 3; 
     FIG. 5 is a side elevational view of an individual fastener of the strip of fasteners of FIG. 1 showing upper and lower plates each having a single aperture formed therein that are generally aligned with each other for receiving a rivet therethrough; 
     FIG. 6 is a view similar to FIG. 5 taken partially in section through the apertures of the plates; 
     FIG. 7 is an enlarged fragmentary sectional view of the upper plate aperture taken along line  7 — 7  of FIG. 3; 
     FIG. 8 is an enlarged fragmentary sectional view of the lower plate aperture taken along line  8 — 8  of FIG. 3; 
     FIG. 9 is a cross-sectional view of a rivet and a pilot nail separably attached at a hollowed out end of the rivet for driving through the conveyor belt and setting of the rivet in the plate apertures of the fastener; 
     FIG. 10 is a cross-sectional view of the installation of the fastener on a belt end showing the rivet and nail being driven with the hollowed end of the rivet being upset along an inclined anvil surface; 
     FIG. 11 is a view similar to FIG. 10 after the rivet has been set in the lower plate aperture showing the set, curled up rivet end in the lower plate aperture; 
     FIG. 12 is a side elevational view of an individual fastener riveted onto a belt end with the hinge pin installed through the arcuate loops thereof; 
     FIG. 13 is a perspective exploded view of an applicator tool that can be used for installing the single rivet, hinged belt fasteners herein showing a channel-shape body including a plurality of recesses in a support surface thereof above which the lower plate apertures of the fasteners are to be aligned; 
     FIG. 14 is a sectional view showing the configuration of one of the recesses including an anvil surface for curling of the hollow rivet end and an abutment surface for the nail heads; and 
     FIG. 15 is a side elevational view of the installation process using the applicator tool of FIG.  13 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In FIGS. 1 and 2, a strip  5  of integrally joined hinged belt fasteners  10  is shown for being attached on end portions  12  of conveyor belts  14  each by a single rivet  16  (FIG.  12 ). In this regard, each of the fasteners  10  includes upper and lower plates  18  and  20  connected by arcuate hinge loops  22  and  24  with the plates  18  and  20  each including a single rivet receiving through aperture  26  and  28 , respectively, formed therein. For being integrally connected together in the strip  5 , between each adjacent pair of fasteners  10  is an integral bridging portion  29 , as can best be seen in FIGS. 1 and 3. More specifically, the bridging portion  29  as shown spans between the lower plates  20  of adjacent fasteners  10  with there being a gap  31  between upper plates  18  of adjacent fasteners  10 . The bridging portion  29  can be notched so that during conveyor operations, the fasteners  10  can separate from each other as by bending and breaking at the notched portion  29  therebetween. 
     Preferably, the size of the apertures  26  and  28  relative to their respective plates  18  and  20  is maximized to allow large rivet heads to be set therein so as to assist in providing the fasteners  10  with a high PIW (pounds per inch of width) rating, e.g. 300 or greater, to provide a low cost, high strength fastener  10  good for use in agricultural and other light to medium duty conveyor belt applications. The fasteners  10  are of a high strength metal material such as a No. 304 stainless steel material and can be produced by starting with a strip of the stainless steel material and subjecting it to a progressive die stamping process in which various metal working stages occur such as punching and coining of the strip to produce a strip as shown in FIG. 3 before being bent and folded over into the FIG. 1 form for low cost, high-volume production of the fasteners  10  herein. 
     Referring to FIG. 12, when the fasteners are riveted onto belt end  12  they can be hingedly attached to another belt end with similar fasteners riveted thereon via hinge pin  30  inserted through mating loops of the respective fasteners. Accordingly, the engagement area between the pin  30  and the loops  22  and  24  can see significant tension forces during conveyor operations. Prior fasteners such as in the previously mentioned &#39;359 patent individually form their fasteners so that their loops are thicker in cross-section than the fastener plates. As the present fasteners  10  are formed from stamped metal, the thickness of the plates  18  and  20  and the loops  22  and  24  are substantially constant except at the coined outboard edge portions  19  and  21  of the respective plates  18  and  20 , as can be seen in FIG.  4 . The coining of the edge portions  19  and  21  can be relatively sharp, i.e. approximately 30°, to provide a biting action into the belt  14  for improved holding power when the fastener  10  is riveted onto the belt  14 . To obtain the thickness needed for strength in the loops  22  and  24 , the metal stock strip from which the fasteners are formed is provided with the desired thickness, i.e. on the order of approximately 0.089 inch thick. The above thickness of the fasteners  10  is relatively large given the small size of the fasteners  10  herein, and has been found to provide the fasteners  10  with sufficient strength for the primary application for which they are designed, i.e. agricultural conveying systems such as for hay baling. In addition, the thicker plates  18  and  20  provide the fastener  10  with more metal that can be abraded during conveyor operations. In this manner, the fasteners  10  have improved wear resistance, and can maintain their strength sufficiently high over time to resist against premature failure thereof. 
     Another strength enhancing feature of the present fasteners  10  is the symmetrically oriented loops  22  and  24  at the rear of the plates  18  and  20 . In typical hinged belt fasteners, the arcuate loops are offset to one side on the plates so that they can be mated with the projecting loops of an opposing fastener on another belt end while keeping the corresponding plates of the opposing fasteners in alignment with each other. Offset loops can create undesirable force imbalances in the fastener during conveyor operations. Accordingly, the present fasteners  10  have their loops  22  and  24  oriented symmetrically relative to the plates  18  and  20 ; that is, the loops  22  and  24  are equally spaced on either side of longitudinal axis  10   a  of the fastener  10 , as can best be seen in FIG.  3 . In addition, because the plates  18  and  20  include only single respective rivet apertures  26  and  28  that have a generally circular shape and are centered on the plates  18  and  20  so that their centers lie on the fastener axis  10   a , the loops  22  and  24  are likewise symmetrically oriented about the apertures  26  and  28 . With the symmetrical orientation of the loops  22  and  24  relative to the plates  18  and  20 , as well as to the single apertures  26  and  28  therein, it has been found that the loops  22  and  24  will more equally share loads that are applied to the fastener  10  when riveted to the belt end  12  during operation of the spliced conveyor belt  14 . 
     Although the belt fasteners  10  can be made in various sizes, the illustrated fasteners for use in hay balers are less than one inch in length to pass about the small diameter pulleys in a hay baler. The illustrated individual fasteners are only about 0.410 inch in width with apertures that are about 0.250 inch in diameter. Typically, the belt fasteners  10  are joined to each other in strips of predetermined length, e.g. seven and fourteen inch strips. 
     As previously-mentioned, in the hay baler application it is particularly important for the fasteners  10  to avoid catching on any wrapping of the bales, and thus the rivet heads should remain flush or recessed below the plane of the outer surface  18   a  or  20   a  of the apertures  26  and  28  of the plates  18  and  20  in which they are seated. It is further desirable that the rivet heads be formed so as to substantially fill the relatively large apertures  26  and  28  in the respective fastener plates  18  and  20  for maximum holding power of the fasteners  10  on the belt end  12 . 
     The preferred rivets  16  that are to be used for attaching the fasteners  10  herein to belt ends  12  are provided with a rivet shaft  32  having an enlarged, preformed head  34  at one end and a cylindrical wall portion  36  at the other end of the shaft, as can be seen in FIG.  9 . The cylindrical wall portion  36  provides a hollow cavity  38  in which an upper end  40  of a pilot nail  42  is received to form a rivet and nail assembly  44 , as is known. The cylindrical wall  36  can be crimped so as to securely yet removably attach the nail end  40  to the rivet end  36  with an enlarged flanged head  46  of the nail  42  spaced slightly below the bottom of the rivet wall portion  36 . The nail head  46  is provided with upper head or anvil surface  47  for deforming of the rivet end  36  during installation of the fastener  10 , as will be more thoroughly described hereinafter. 
     As discussed, the apertures  26  and  28  are large relative to their respective plates  18  and  20 . By way of example and not limitation, with the 0.089 inch thick stainless steel fastener  10 , the upper plate  18  can have a width of 0.330 inch between sides  48  and  50  thereof, and the lower plate  20  can have a width of 0.410 inch between its sides  52  and  54 , which due to the presence of bridging portion  29  can lie thereon. In the prebent form of FIGS. 3 and 4, the length of the fasteners  10  between outer edges of  19   a  and  21   a  of coined outboard edge portions  19  and  21  is approximately 2.0 inches. Referring to FIGS. 7 and 8, the diameter, d 1 , of aperture  26  of the upper plate  18  along the upper plate surface  18   a  is approximately 0.250 inch, and the diameter, d 2 , of the aperture  28  in plate  20  along surface  20   a  thereof is approximately 0.280 inch. As is evident, the apertures  26  and  28  are very large openings in the plates  18  and  20  with diameters d 1  and d 2  that are preferably at least half the width of the plates  18  and  20  and with the diameters d 1  and d 2  in the specific example set forth above being much greater than half the width of their respective plates which allows heads of the rivet  16  to likewise be large for improving the holding power of the fastener  10 , as previously discussed. 
     With continuing reference to FIGS. 7 and 8, the configuration of the walls about the apertures  26  and  28  will next be more particularly described. As shown, the through apertures  26  and  28  extend from the outer surfaces  18   a  and  20   a  of the respective plates  18  and  20  to their inner surfaces  18   b  and  20   b . These through apertures  26  and  28  are provided with various sections having different configurations including outer, intermediate, and inner sections. The outer sections of the apertures  26  and  28  extend from the respective outer diameters d 1  and d 2  at the plate surfaces  18   a  and  20   a  and taper inwardly to the intermediate sections by way of annular, inclined surfaces  56  and  58 . The annular surfaces  56  and  58  extend about enlarged, countersunk recesses  56   a  and  58   a  of the apertures  26  and  28  for receiving the preformed head  34  and the upset head  36  of the rivet  16  therein. Inclined surface  56  serves as a seat for the preformed rivet head  34  when the fasteners  10  are installed on a belt end  12 . In this regard, the head  34  is sized so that the diameter across the top surface  34   a  thereof is substantially the same or slightly less than diameter, d 1 , across the inclined surface  56  along the plate upper surface  18   a . The lower tapered surface  34   b  of the nail head  34  has an inclination substantially matching that of the inclined surface  56  for seating thereon. The inclined annular surface  58  can serve as a guiding surface for the deformed rivet end  36  as it is being upset and curled upwardly about the rivet shaft  32  for being set in the enlarged recess  58   a  in the aperture  28 . 
     The inclined surfaces  56  and  58  have a frustoconical shape that extend annularly about enlarged countersunk recesses  56   a  and  58   a  in their respective apertures  26  and  28 . At the inner end of the surfaces  56  and  58  are the respective intermediate sections of the apertures  26  and  28  including short straight, cylindrical wall surfaces  60  and  62  which each have a diameter slightly greater than that of the shank  32  of the rivet  16  so that it can be received therethrough. From the inner ends of the straight, cylindrical wall surfaces  60  and  62  are respective reverse tapered surfaces  64  and  66  of the inner section of the apertures  26  and  28  and which extend annularly and have a frustoconical shape with diameters at their innermost ends slightly less than the diameters d 1  and d 2 . The reverse tapered surfaces  64  and  66  open to the area between the plates  18  and  20  at annular lips  68  and  70  that are raised from respective plate surfaces  18   b  and  20   b.    
     Installation of the fasteners  10  on a conveyor belt end  12  will next be described with reference to FIGS. 10 and 11. In FIG. 10, the fastener plates  18  and  20  are clamped tightly about the belt end portion  12  on respective upper and lower surfaces  14   a  and  14   b  of the conveyor belt  14  during riveting of the fastener  10  thereto. For installing the fasteners  10 , the lower plate  20  can be supported on a support surface  72  of an installation tool such as applicator tool  74  (FIG.  13 ). Lower plate apertures  28  can be aligned over recesses  76  in the tool support surface  72  configured to upset the rivet end  36  of the rivet and nail assembly  44 , as will be more fully described hereinafter. With the lower plate apertures  28  so aligned over the tool recesses  72 , the rivet and nail assemblies  44  can be driven through the belt  14  as by hammer blows to the rivet head  34  with pointed leading end  77  of the pilot nail piercing the belt  14  and forming a pilot hole for the larger diameter rivet  16  thereover. Driving of the assembly  44  causes the rivet head  34  to enter the enlarged recess portion  56   a  of the aperture  26  as the rivet shank  32  is driven through the belt  14  with the rivet end  36  received in the aperture  28  and projecting out from the enlarged recess  58   a  thereof. 
     The belts  14  to which the present fasteners  10  are to be riveted are typically of a resilient material such as of an elastomeric or rubber material. Thus, with the nail head  46  engaging against abutment surface  78  in the recess  76  and the inclined surface  34   b  of the rivet head  34  seating against the recess inclined surface  56 , continued hammer blows cause the plates  18  and  20  to compress the resilient material of the belt  14  therebetween with the rivet material at end  36  thereof deforming and flaring out as the bottom of the rivet end  36  is forced against the nail head anvil surface  47  so as to deform the end  36  radially outwardly, and then against anvil surface  88  of recess  76  shown in FIG. 14 to curl the end  36  up about the rivet shaft  32  for forming the upset rivet head. The annular surface  58  is coordinated in size with recesses  76  to receive the curled, upset rivet head. 
     After the curled rivet head  36  is formed, continued hammering can cause further shifting of the head  34  in upper plate aperture  26  so that the lower surface  34   b  of the head  34  seats tightly against inclined surfaces  56  therein. This shifting of the rivet head  34  in aperture  26  is sufficient so that it seats in recess  56   a  with its top surface  34   a  flush or recessed below plate outer surface  18   a.    
     During driving of the assembly  44  to form the upset rivet head  36 , the compressed belt  14  will have a reduced thickness, A, between the upper and lower surfaces  14   a  and  14   b  thereof as clamped by the fastener plates  18  and  20 , as shown in FIG.  10 . When the riveting of the fastener  10  to the belt  14  is complete and the driving force applied to the rivet  16  is removed, the material of the belt  14  will resiliently slightly expand between surfaces  14   a  and  14   b  thereof to a larger thickness, B, as shown in FIG.  11 . It has been found that this belt expansion or decompression is sufficient to draw or pull the upset rivet head  36  into the enlarged recess  58   a  of the aperture  28 . As shown, the rivet  16 , and recesses  58   a  and  76  are preferably sized so that as the driving force is removed, the rivet head  36  will be substantially flush with or recessed slightly below the outer surface  20   a  of the lower plate  20  so that it does not present a catching location for conveyed products such as the wrapped hay bales previously discussed. In addition, the rivet  16  is sized so that the fastener  10  can be used on belts  14  which range in thickness by 0.094 inch. With the previous exemplary sizes, the fastener  10  can be utilized on belts  14  of thicknesses between 0.125 inch and 0.218 with the upset rivet head  36  increasing in size as the belt thickness decreases. For thinner belts, the anvil surface  88  will curl more metal for the upset rivet head than it does for the rivet piercing a thicker belt. This is advantageous in that it allows end users to reduce the number of different types of fasteners they keep in inventory for use on different sizes of belts. 
     As previously discussed, it is particularly important for the rivet head  36  to be provided with a good set in the aperture  28  and, in particular, so that the head  36  substantially fills in the countersunk recess  58   a  so that there is little or no loose play between the flared out and curled up rivet head  36  and the inclined surface  58  when the fastener  10  is riveted to the belt  14 . For this purpose, application tool  74  can be utilized for riveting of the fastener  10  to the belt  14  with a plurality of the recesses  76  formed in a channel-shaped structural body member  80  of a case hardened steel material. No additional hardened bushing inserts for forming the upset rivet heads are required with the present tool  74  thus keeping its cost to a minimum. And because of the previously described compression and decompression of the belt  14  as the fasteners  10  are being installed, the upset rivet heads  36  will not protrude over the plane of the plate surface  20   a  despite being formed in recesses  76  of the tool  74 . 
     More specifically, web  82  of the channel body  80  has leg flanges  84  and  86  depending from either side thereof so that it can readily be transported to different conveyor belt locations so that the legs  84  and  86  rest on a support surface thereat with the working surface  72  of the channel web  82  raised thereabove. One of the recesses  76  formed in the web  82  is depicted in FIG.  14  and includes an inclined surface  88  which is disposed above the nail head abutment surface  78 . The diameter, d 3 , of the surface  88  along the tool support surface  72  is sized to be approximately the same or slightly smaller than diameter, d 2 , of the inclined surface  58  of lower plate aperture  28 . Accordingly, with the exemplary dimensions set forth earlier, the diameter, d 3 , can be approximately 0.260 with the inclined surface  88  preferably extending arcuately therefrom to its innermost end at abutment surface  78  to a diameter of approximately 0.183 inch thereat. The preferred arcuate surface  88  has a radius of curvature of 0.052 inch with a vertical drop from web top surface  72  to the juncture with the abutment surface  78  of 0.0349 inch. The abutment surface  78  tapers inwardly to through opening  90  formed in the channel web  82  which has a diameter of approximately 0.125 inch. 
     Thus, when the rivet and nail assembly  44  is driven for riveting of the fastener  10  onto the belt  14 , the nail shank  92  will project into through opening  90  with the nail head  46  engaging against abutment surface  78  so that nail head anvil surface  88  is circumscribed by arcuate inclined anvil surface  88  of the installation tool recess  76 , as can be seen in FIG.  10 . In this manner, the rivet end  36  is deformed and flared out by nail anvil surface  47  and then guided upwardly with continued driving of the rivet  16  by inclined anvil surface  88  in the recess  76  for being curled back upwardly about the rivet shaft  42 . In addition, because of the close sizing of the diameters between the tool recesses  76  and the overlying plate recesses  58   a , the inclined surfaces  58  in the lower plate apertures  28  also assists in providing the rivet head  36  with an improved set in enlarged recess  58   a  with the upset rivet head  36  engaged against or closely spaced from the surface  58 . 
     Turning to the details of the construction of the installation tool  74 , fastener position pins  94  and  96  are attached to the channel web  82  projecting upwardly therefrom for locating the fasteners  10  so that their lower plate apertures  28  are in overlying relation to the tool recesses  76 . The pins  94  are aligned with the recesses  76  and can be provided at every other recess. Accordingly, the pins  94  can be fit between the hinge loops  22  and  24  symmetrically oriented about the plate apertures  26  and  28  of every other fastener  10  in the strip  5 . Further, the aligned pins  94  are spaced at a predetermined distance from the recesses  76 , e.g. 1.00 inch, so as to serve as a belt stop to locate the belt end  12  in proper position between the plates  18  and  20 . On the other side of the row of recesses  76 , there are two positioning pins  96  located offset from the last pair of recesses  76  at either end of the row of recesses  76  to fit between the last pair of lower plates  20  of adjacent fasteners  10  at either end of the fastener strip  5 . The pins  96  fit in spaces  98  between adjacent lower plates  20  formed by beveling of the corners  100  and  102  of the fastener plates  18  and  20  at the respective outboard edge portions  19  and  20  thereof (FIGS.  1  and  2 ). 
     The tool  74  further includes a belt clamp  104  for securely clamping the belt  14  against the support surface  72  with end  12  thereof disposed in position between unclenched upper and lower plates  18  and  20  of the fastener strip  5 . The belt clamp  104  can include an elongate clamp bar  106  mounted on channel member  80  via cylindrical compression springs  108  and  110  at either end thereof for biasing the clamp bar  106  upwardly relative to the channel web  82  to allow a belt  14  to be slid thereunder onto surface  72 . 
     Overcenter cam lock clamps  112  and  114  are provided and include threaded mounting posts  116  and  118  which are inserted through openings  120  and  122  at either end of the bar  106  aligned over the cylindrical compression springs  108  and  110  which, in turn, are placed over internally threaded apertures  124  and  126  in channel web  82  so that the post  116  and  118  can be threaded therein with the compression springs  108  and  110  disposed between the clamp bar  106  and base upper surface  72 . Over center clamps  112  and  114  each include a cam lever member  128  and  130  that are pivotally attached to enlarged fixed heads  132  and  134  at the upper ends of respective posts  116  and  118  by pivot pins  136  and  138 , respectively. 
     The pivot pins  136  and  138  extend through a yoke-shaped cam portion  140  and  142  of the cam lever member  128  and  130  and through mounting post heads  132  and  134  for pivoting of the cam portions  140  and  142  thereabout. Handle portions  144  and  146  project upward from the respective cam portions  140  and  142  of the cam lever members  128  and  130 . The cam portions  140  and  142  are provided with a contoured outer surface  140   a  and  142   a  so that when an operator pulls down on the handles  144  and  146  to pivot the cams  140  and  142  about their respective pivot pins  136  and  138 , the contoured surfaces  140   a  and  142   a  will cam against the clamp bar  106  forcing it downwardly against the bias provided by compression springs  108  and  110  and shifting into a locking positions when the handles  144  and  146  are pivoted through an angle of approximately ninety degrees so as to securely clamp the belt  14  between the bar  106  and the support surface  72  of the tool body  80 . With the belt  14  securely clamped by the belt clamp  104  of the tool  74  and the fastener strip  5  properly aligned relative to the tool recesses  76 , the fasteners  10  can be installed on the belt  14  in a relatively simple manner by subjecting the rivet and nail assemblies  44  to hammer blows for riveting the fastener  10  onto the belt end  12 , as previously described. 
     While there have been illustrated and described particular embodiments of the present invention, it will be appreciated that numerous changes and modifications will occur to those skilled in the art, and it is intended in the appended claims to cover all those changes and modifications which fall within the true spirit and scope of the present invention.