Abstract:
A portable belt lacer fastens to an associated belt end a plurality of side-by-side connectors of the type having opposing shanks interconnected by central eye loops with staples that extend through the opposing shanks and the associated belt end. The belt lacer includes a bending die configured to bend free ends of the staples upon penetration into and through the associated belt end, and a press head operably connected with said bending die with a die that is shifted vertically in the direction of said bending die to insert the staples. Positioners upstanding from the bending die are configured to abuttingly engage the connectors to precisely locate the same on the bending die, and a centering rod is inserted through the eye loops of the connectors, and is laterally shiftable toward and away from the bending die, such that the connectors are accurately and positively positioned along the associated belt end by capturing the connectors between the positioners and the centering rod.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to belt lacers of the type used to fasten connectors onto the ends of conveyor belts and the like, and in particular to a portable belt lacer. 
     When fastening belt connectors or their connective fasteners onto the ends of conveyor belts, power belts, or the like, one problem is ensuring a precise penetration of the holding staples, the tips of which have been placed in the holes of the upper fastener shank, into the holes of the lower fastener shanks that are positioned in the bending die, i.e., subsequent to penetration of the belt end concerned. In the course of fastening the connective fasteners, the upper fastening shanks are pressed down upon the surface of the belt. A precise motion of the fastener shanks towards one another must be ensured both for different wall thicknesses, as well as for different belt elasticities and other belt characteristics. 
     For this reason, the user often selects a sufficiently large amount of play between the fastening shanks and associated connector holes. However, this results in diminished fastening strength of the connective fasteners and ultimately of the belt connectors relative to fastener location and hold. If connective fasteners of relatively strong material are used instead, positioning of the connective fasteners during fastening of the connective fasteners is simplified and, in particular, a relatively slight amount of “hole play” is made possible. However, the deformative forces required during attachment of such belt connectors are quite high. 
     DE 41 40 743 A1 discloses a device of the above-named type in which connective fasteners of comparatively thin sheet metal material are used, whereby the eye loops are produced from the sheet metal material as folded loops of U-shaped cross section to increase resistance to stress and wear. This thin sheet metal material requires guide holes for the holding staples with the smallest possible amount of guide play in order to achieve a flawless seating and hold of the connective fasteners and, consequently, for the belt connectors, onto the ends of the belts. The complicated interaction of the individual centering agents is a disadvantage of this device, which also causes the device to be quite expensive in construction. Aside from this, the rod, which can be slid into the bending die and which the eye loops of the connective fasteners wrap around, performs no centering function in this device. Finally, the device does not allow itself to be converted to other sizes of belt connectors. Furthermore, it does not allow precise contact of the connective fasteners in the channel of the press head upon initial centering of the press head over the bending die via a peg connected to the press head, which peg can be placed in a centering bore of the bending die. 
     In contrast to such prior art devices, in the present invention, because of the tight motion tolerances desired, diverse centering devices are provided in order to guarantee a flawless introduction of the holding staples into the guide holes of the lower fastener shank upon driving in the holding staples. Hence, one side of the bending die has centering lamellae or elements between the eye loops that connect the fastener shanks of the respective connective fasteners, and the other side has centering wedges or pins that fit within V-shaped recesses on the back side of the fastener shanks lying upon the die. Additionally, the underside of the press head is provided with a centering stop for the back sided end of the upper fastener shank of the connective fasteners. 
     SUMMARY OF THE INVENTION 
     One object of the invention is to provide a device of the above-named type in such a way that an optimal centering of the belt connectors can be achieved during their fastening onto the belt using agents of simple construction. 
     Another object is achieved for a device of the above-mentioned type in that the centering of the connective fasteners is achieved via the means which articulate between the eye loops, as well as via the rod, whereby the centering rod that is slid into the bending die positions the connective fasteners against the centering means found between the eye loops. 
     In the device according to the present invention, the rod therefore takes on the function of a component which facilitates centering. Upon sliding the rod into the connective fasteners that have been placed upon the bending die, the rod contacts the eye loops of the connective fasteners and positions the connective fasteners against the centering means or members which are found between the eye loops. The centering members arranged between the eye loops are constructed as pins according to a particular embodiment of the invention. Aside from these centering means, specifically the rod and the pins, the device according to the present invention fundamentally requires no further centering mechanisms. 
     Since the centering members that fit between the eye loops are constructed as pins according to the preferred embodiment of the invention, these centering members require only a small amount of space, such that sufficient room remains for sliding in the rod. The rod represents a fixed pivotal axis for the connective fasteners, in that the possibility exists to bend those fastener shanks of the connective fasteners, which are impinged via upper die and the connective fasteners, around this fixed axis until these fastener shanks contact the belt. In this fashion, it is ensured that said fastener shanks are bent in a specific, predefined manner, in a position in which the holes of the corresponding fastener shanks, which incorporate the belt between them, are aligned with one another. 
     According to a particular embodiment of the invention, it is foreseen that the rod is slidably mounted in the bending die, parallel to the axis of the rod. On the one hand, this enables optimization of rod position relative to the connective fasteners, specifically to the eye loops of the connective fasteners, such that the rod lies against the eye loops and thus takes on the function of a centering means or member. On the other hand, the adjustability of the rod allows different sizes of belt connectors to be processed in the same bending die. The various sizes of belt connectors differ in the length of the fastener shanks in particular, so that, at an unchanged position of the connective fasteners relative to the bending die, only the position of the rod needs to be changed for the purpose of contacting the eye loops of the connective fasteners. 
     In particular, the rod is mounted such that it is continuously slidable in parallel, although the adjusting agents for sliding the rod are self-limiting. This ensures for all rod positions that the rod will not slide in the direction of any transverse forces acting upon it whenever such transverse forces occur. 
     As a general rule, it is not necessary to provide for more than two different parallel rod positions, in order to position more than two sizes of belt connectors. In order to bring about the positioning of two belt connector sizes, axial translocation or shifting of the mounting elements for the rod, combined with a rotational motion of the mounting elements by 180 degrees, are advantageously provided. The rod can thus be slid into the same bores of the mounting elements. 
     According to a preferred embodiment of the invention, it is provided that the rod is mounted in aligned bore holes of mounting elements that can be slid by means of the adjusting members, whereby the mounting elements have stops for the belt end that has been placed between the fastener shanks of the connective fasteners. A corresponding parallel repositioning of the stop for the current belt end to be processed therefore goes along with parallel repositioning of the rod. 
     According to one embodiment of the invention, it is foreseen that the bending die has reversing recesses for reverse bending the tips of the holding staples, whereby the reversing recesses are of shallow construction. In the area of the connective fasteners, the belt connection is consequently very shallow in relation to conveyor belt thickness. The bending forces generated during the reversing of the tips of the holding staples are also absorbed by the centering members. Shallow reversing recesses are understood to mean those which have no greater depth than the thickness of the respective fastener shanks relative to their dimension in the direction of conveyor belt thickness. Contrary to various prior art, it is, in particular, not necessary to bend back the end sections of the holding staples in the direction of the respective fastener shanks so that these end sections traverse holes in the fastener shanks. 
     Based on the centering of the connective fasteners via the centering members according to the present invention, one can forego the need for centering means or agents in the area of the upper die. To this extent, it is considered expedient for the upper die to have a planar upper die face, in particular to have a planar upper die face that strikes the holding staples at an angle. This angle corresponds to less than 10 degrees, whereby the upper die is oriented such that, on the basis of the design of its inclined upper die face, it initially strikes that area of the respective holding staples that faces the free end of the fastener shank. Correspondingly, the press head, which comes into contact with the fastener shanks, preferably also has an inclined contact face. As a result, upon placing the press head on the belt connector and/or upon inducement of an upper die force, those areas of the belt connector that face away from the eye loops are contacted or impinged first. The main compressive forces are thus introduced into the belt connector at a large distance from the rod. 
     It is considered particularly advantageous if the press head and the bending die can be centered by means of pegs, whereby the respective peg is spring mounted. On the basis of this construction, it is, in particular, possible to use connective fasteners having a V-shaped design, rather than a U-shaped design, in their initial configuration, i.e., prior to bending together. Placement of the press head onto the holding staples can occur with the press head at an inclined arrangement to the bending die corresponding to the open angle of the fastener shank, whereby the peg has not yet centered the press head and the bending die, but is instead retracted into the press head or the bending die in opposition to the force of a spring, depending upon in which of these parts said peg is mounted. Not until the fastener legs have assumed their U-shaped form under the influence of the weight of the press head, or that of an external force applied to the press head, does the peg, under the force of the spring, move into the complementary bending die to center the parts. 
     Further features of the invention are presented in the description of the figures and in the figures themselves, whereby it is noted that all individual features and all combinations of individual features are essential to the invention. 
     These and other advantages of the invention will be further understood and appreciated by those skilled in the art by reference to the following written specification, claims and appended drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is represented in the figures on the basis of a preferred embodiment, without being limited to it. Represented are: 
     FIG. 1 is a front view of a portable belt lacer embodying the present invention, without conveyor belt and belt connectors having been placed therein; 
     FIG. 2 is a plan view of a bending die shown in FIG. 1 along with other elements; 
     FIG. 3 is a section through the device shown in FIG. 1, taken along the line III—III, with conveyor belt and belt connectors having been placed therein, prior to deformation of the belt connectors; 
     FIG. 4 is a detail sectional view of the bending die, taken along line IV—IV of FIG. 1; 
     FIG. 5 is a detail view “V” of the bending die according to FIG. 4; 
     FIG. 6 is a sectional view of the device according to the representation in FIG. 3, showing the fastener shanks bending together prior to pressing the holding staples through; 
     FIG. 7 is a sectional view to FIG. 6, where the holding staples have been partially pressed through; and 
     FIG. 8 is a sectional view according to FIGS. 6 and 7, upon completion of the fastening process. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     For purposes of description herein, the terms “upper”, “lower”, “right”, “left”, “rear”, “front”, “vertical”, “horizontal” and derivatives thereof shall relate to the invention as oriented in FIGS. 1 and 2. However, it is to be understood that the invention may assume various alternative orientations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification, are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise. 
     The illustrated device for fastening belt connectors onto conveyor belts consists essentially of two components, comprising a press head  1  and a bending die  2 . 
     The bending die  2  has a hollow base  3  of rectangular cross section. A snaker or anvil plate  4 , which actually executes the bending process, is positioned on top of the base  3  and is connected to the base  3  by means of a large number of screws  5  that are countersunk in the plate  4 , whereby these screws traverse bore holes in the upper wall of the base  3  and are threaded into nuts  6  arranged within the base  3 . In order to cushion the forces introduced into the base  3  during the bending process, an intermediate spacer  7  is placed in the base  3  and mounted there, such that said spacer contacts the upper and lower walls of the base  3 . The anvil plate  4  has a width corresponding to roughly half the width of the base  3 . A support  8  is placed in the area of the other half of the base  3 , next to plate  4 , which support serves to support the belt end  9  of the conveyor belt  10 . A mounting piece  11  in the shape of a right parallelepiped is connected to the lateral wall of the base  3  that faces the anvil plate  4 , which piece is provided with a large number of through holes  12  oriented perpendicular to the upper wall of the base  3 . Each of the two through holes  12 , at a distance of four through holes  12 , serves to accept two centering pegs  13  of the press head  1 . Attachment of the mounting piece  11  to the base  3  is accomplished by means of multiple screws  15  that are threaded into nuts  14 . In the central area, relative to the longitudinal extension of the mounting piece  11 , a handle  16  is connected to those screw bolts that pass through the mounting piece  11  and are threaded into the nuts  14 . By grasping the handle  16 , the bending die  2  can be transported, along with the attached press head  1 , as necessary. 
     On the side oriented away from the base  3 , the anvil plate  4 , which extends in the longitudinal direction of the base  3 , has a planar bearing surface  17  for the lower fastener shank  18  of the connective fasteners  19  of the belt connector  20 . The planar bearing surface  17  is provided with shallowly constructed reversing recesses  21  for reverse bending the holding staples  22  which are pushed through during the fastening of the belt connectors. These to staples consist of staple legs  23  that are pointed in the area of their free ends and a crosspiece  24  which connects them at a right angle. The illustrated belt connectors  20  have fastener shanks arranged in a V-shape as relates to their initial condition before attaching them to the conveyor belts, and lower fastener shanks  18  and upper fastener shanks  25  that are connected by means of an eye loop  26 . In order to position the connective fasteners next to one another in predefined fashion, in particular at exact parallel relationship, two rods  27  are provided which contact the upper side of the lower fastener shank  18  and are welded or otherwise attached to it. 
     Each fastener shank  18 ,  25  has two or four holes  28 ,  29 , depending on whether the fastener shank in question serves to accommodate one or two holding staples  22 . Relative to the initial position of the belt connectors, the respective holding staple  22  is put into the holes  29  of the upper fastener shank  25 , whereby the tips of the staple legs  23  of the holding staple  22  project slightly beyond the lower surface of the upper fastener shank  25 . During attachment of the belt connectors  20  to the conveyor belt  10 , which will be explained in greater detail below, the respective holding staple  22  is advanced in the direction of the lower fastener shank  18 , whereby the holding staple  22 , with its leading pointed areas of the staple legs  23 , is introduced into the holes  28  of the lower fastener shank  18 . Upon further pressing of the staples  22 , the free ends of staple legs  23  contact the anvil plate  4  and are reverse bent in the direction of the mounting piece  11  within the area of the reversing recesses  21 . 
     Centering agents or members are provided to position the belt connectors  20  onto the conveyor belt in precise, predefined fashion during fastening. In the illustrated example, centering pins  30  are set in bore holes of the anvil plate  4 . The centering pins  30  are arranged parallel to the through holes  12  in the mounting piece  11 , whereby a large number of centering pins  30  are positioned in the longitudinal direction of the anvil plate  4 . Each centering pin  30  projects far enough above the planar bearing surface  17  of the anvil plate  4 , so as to roughly coincide with the upper contour of the lower fastener shank  18  of connective fasteners  19  when placed upon the anvil plate  4 . If the respective connective fastener  19  has two identical eye loops  26  that are arranged parallel to one another and which connect the two fastener shanks  18  and  25 , the respective centering pin  30  fits between the eye loops  26  of these connective fasteners  19 , and indeed, as in the representation in FIG. 4, in the area in which the eye loops  26  transition into the lower fastener shank  18 . The centering pin  30  could fundamentally also fit between adjacent connective fasteners  19 , if they have only one eye loop  26 . A centering rod  31  is provided as a further centering agent or member, which contacts the connective fasteners  19  in the inner vertex  32  of the eye loops  26 . The centering rod  31  is placed with a minimum amount of play through aligned bore holes of mounting elements  33  that are freely rotatable about an axis  34 , but held axially fixed in a cylindrical adjusting member  35 . The respective adjusting member  35  traverses a bore hole in the mounting piece  11  and said member is provided with an exterior, inclined groove  36 . An extension  37  of a bolt  38  mounted in the mounting piece  11  articulates with said groove. A finger tight adjusting knob  39  is connected to the adjusting member  35  on the side facing away from the respective mounting element  33 . Upon turning the adjusting knob  39 , the adjusting member  35 , and hence the mounting element  33 , are moved axially in the direction of the double arrow X according to the predetermined direction of rotation. 
     The centering rod  31  can thus be shifted or slid by means of the four existing adjusting members  35 . It is to be understood that it is not necessary for the respective mounting element  33  and the associated cylindrical adjusting agent  35  to be made up of two separate components. If these design elements were formed as one physical unit, then it can be rotated by 180 degrees upon removal of the centering rod  31 , so that the centering rod  31  could then be placed through the sections of mounting element  33  at the position of the component that has now been slid axially by a predefined amount. If the adjusting knobs  39  are constructed as nuts, one can clearly determine from the respective upper surfaces of the adjusting knobs  39  into which of the two possible parallel positions the centering rod  31  has been slid and hence for which size belt connector the device has been set. 
     The illustrated press head  1  is provided with a handle  40 . The press head  1  has a thick walled press head sleeve  42  with a guide channel  41 . A reciprocating or depressible upper die  43  is guided within the guide channel  41 , which die is non-rotatably mounted within the press head  1 . The leading upper die face  44  and also the leading surface  45  of the press head sleeve  42  are arranged at an angle of greater than 90 degrees, and up to 100 degrees, relative to the axis of motion of the upper die  43 , such that that die area and/or that area of the press head sleeve  42 , which is directed toward the staple leg  23  of the holding staple  22  that is directed away from the eye loop  26 , leads. In the area of its two staple legs  23 , the respective holding staple  22  is guided within the guide channel  41 , at least in relation to the longitudinal extension of the crosspiece  24 . 
     Both centering pegs  13  are mounted in the press head  1  in axially slidable fashion, and are biased outwardly by compression springs  46 . The upper interior faces of mounting pieces  11  are tapered or flared outwardly to receive or guide centering pegs  13  therein, as explained in greater detail below. 
     In order to fasten a row of belt connectors  20  onto the end of the conveyor belt  10 , the belt connectors  20  are placed on the anvil plate  4 , with the lower fastener shank  18  positioned against the centering pins  30 . After pre-positioning the adjusting members  35 , the centering rod  31  is either slid through the bore holes of the mounting elements  33 , or else the centering rod  31  is first placed through the bore holes of the mounting elements  33 , and then the centering rod  31  is slid in parallel to its centering position, in which it lies against the eye loops  26  of the connective fasteners  19  in the area of the vertex  32 . The end  9  of the conveyor belt  10  is then placed between the spread, V-shaped fastener shanks  18  and  25  onto the support  8 , whereby the end surface of the conveyor belt  10  contacts the stopping faces  47  of the mounting elements  33 . 
     In this initial position, the press head  1  is placed upon the bending die  2  in the manner illustrated in FIG. 3, whereby the two centering pegs  13  are fully retracted into the press head  1  on account of the placement position, which is just slightly out of plumb or vertical. Because of the weight of the press head  1 , the respective upper fastener shank  25  of the connective fastener  19  is pressed down against the belt  10  once said head is placed upon the bending die  2 , whereby the upper die  43  moves up out of the way. As a result of the slight tipping motion of the press head  1 , which takes place relative to the bending die  2 , the centering pegs  13  are shifted into an aligned position to the through holes  12  of the bending die  2 , such that the centering pegs  13 , under the influence of the compression springs  46 , extend out of the press head, and are received completely into the bending die  2 . This relationship is illustrated in FIG.  6 . The expanded section  48  of the upper die  43 , which sticks out of the top of the press head  1 , is subsequently impacted or impinged via the effect of a hammer or the like, and hence the upper die  43  is driven downward. The respective holding staple  22  is driven through the conveyor belt  10  and the lower fastener shank  18  of the connective fastener  19  by means of the upper die  43  in the previously described sense, and bent along the anvil plate  4  in the direction of the eye loop  26  of the connective fastener  19 . An intermediate step of the connection process is illustrated in FIG. 7, and the completed connection process is shown in FIG.  8 . The angled surfaces of the upper die  43  and the press head sleeve  42  prevent the fastener shanks from moving away in the direction of their free ends. 
     In each case, impacting or impingement of the press head  1  results in the connection of only a few (e.g., one or two) of the connective fasteners  19  with the conveyor belt  10 . Consequently, the press head  1  is removed from the bending die  2  following the connection, and shifted laterally to the next connective fastener(s)  19  slated for connection, i.e., transferred laterally by the desired number of through holes  12 . The process shown in FIG.  3  and FIGS. 6 to  8  is then repeated. 
     In the foregoing description, it will be readily appreciated by those skilled in the art that modifications may be made to the invention without departing from the concepts disclosed herein. Such modifications are to be considered as included in the following claims, unless these claims by their language expressly state otherwise.