Patent Publication Number: US-2011056349-A1

Title: Apparatus to Feed and Shear Metal Bars, and Relative Method

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention concerns an apparatus to feed and shear metal bars and the relative method, usable in association with automatic machines, such as for example stirrup machines, bending machines, shaping machines, binding machines, storage apparatuses or other machines for working or storing bars sheared to size. In particular, the apparatus according to the invention allows to feed, substantially continuously, metal bars sheared to size to an automatic machine, eliminating down times and waiting times, facilitating the discharge of the off-cuts and increasing shearing accuracy and productivity of the machine. 
     2. Description of Related Art 
     Automatic machines for working metal bars sheared to size are known, such as for example stirrup machines, bending machines, shaping machines, binding machines or others, which work one or more bars at a time in order to produce shaped products for the building trade or other type of product. Stores are also known, suitable to collect segments of bars sheared to size. 
     Upstream of such machines, or upstream of the collection stores, a feed store is normally provided in which bars of different diameter are disposed in homogeneous bundles, and from which the bars to be sent to the machine are picked up on each occasion, according to the specific requirements. 
     Apparatuses are also known, disposed between the feed store and the automatic machine, and provided with shearing units suitable to feed to the machine segments of bars of the desired length. 
     It is known that, in order to guarantee the correct measurement and sequential shearing of the bars to be sent to the machine, the latter are first aligned with each other on a positioning and transport plane, upstream of the shearing unit, by butting the leading ends, and subsequently transported by a transport member, for example with rollers, belt, chain or other, toward and beyond the shearing unit. The bars are moved until they are taken into abutment with their leading ends, against specific stop elements positioned at fixed pitches downstream of the shearing unit, and able to define the sheared measurements of the bars. 
     Some known apparatuses also have the possibility of moving the positioning and transport plane and the shearing unit with respect to each other, so as to adjust the shearing of the bars to measurements different from those defined by the fixed pitches of the stop elements. 
     This type of known apparatus not only has to provide different movement means for the shearing unit and/or the plane, and also members to activate the stop elements, but also effect a butting operation on the lead ends of the bars, thus causing a tail-end excess or off-cut, due to the difference between the multiple sizes of the segments sheared and the initial length of the individual bars. 
     One of the main disadvantages of this type of known apparatus is the problem of discharging said off-cuts, to allow to start shearing new bars. 
     Shearing apparatuses are also known in which the alignment unit comprises a butting member suitable to cooperate with the tail ends of the metal bars in order to align them longitudinally with respect to each other, and a thruster member configured to thrust the metal bars acting on their tail ends, to take them toward and beyond the shearing unit. 
     The thruster member acts until it takes the tail ends to a predetermined initial distance from the shearing unit. The distance is advantageously a multiple of the measurement of the individual segments into which the metal bars are to be divided. 
     This last type of known apparatus allows to discharge the off-cuts before starting the shearing steps, giving advantages in terms of time and costs of production. 
     Under some operating conditions, however, it is possible that the bars, butted by their tail end, especially during the thrusting step and with bars having a medium/small diameter, reciprocally move due to inertia, thus partly losing their butted condition. Furthermore, difficulties have been found in guaranteeing an effective contact between the butting member and the tail ends of all the bars to be butted. 
     One purpose of the present invention is to produce an apparatus to feed and shear metal bars that allows to considerably reduce the down times due to the operations to discharge the off-cuts, without providing complex members to pick up and discharge them. 
     Another purpose of the present invention is to produce an apparatus that guarantees that the initial alignment of all the bars is maintained, both in the butting step and also during all the sequential shearing steps. 
     The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention is set forth and characterized in the independent claims, while the dependent claims describe other characteristics of the invention or variants to the main inventive idea. 
     An apparatus according to the present invention is applied to feed metal bars to an automatic machine, and to shear said bars into segments. 
     The apparatus according to the present invention comprises at least a shearing unit able to shear the metal bars sequentially into segments of a desired length and to feed them to a work machine, and an alignment and translation unit which feeds the metal bars to the shearing unit and is provided with a butting member suitable to cooperate with the tail ends of the bars so as to align them longitudinally with respect to each other. 
     According to a characteristic feature of the present invention, the butting member comprises at least a magnetic portion, facing toward the tail ends of the metal bars. The magnetic portion is conformed so as to generate a magnetic or electromagnetic force of attraction on the tail ends of the metal bars, so as to attract them towards itself and keep the relative tail ends substantially aligned and in contact with the butting member, also during any possible reciprocal movements of the bars during the butting and thrusting operations. 
     In this way, the tail ends of the metal bars are magnetically attracted and remain attracted by the magnetic portion of the butting member. This guarantees that all the metal bars, even those of average/small diameter, contact the butting member during the butting step with their tail end, and are thus all equally butted. 
     Furthermore, since the butting is carried out on the tail ends of the metal bars, there is a single butting operation, in an initial step that precedes the shearing to size step, to define the positioning of the off-cut to be sheared and discharged downstream of the shearing unit and in the same direction of feed of the bars. This gives a considerable advantage in the continuity of feed of the metal bars to be sheared and therefore the segments to be fed to the automatic machine. 
     The functional combination of the tail-wise butting and the action of magnetic attraction exerted by the butting member guarantees a substantially uniform shearing and positioning of the metal bars, and hence great accuracy and repeatability in making the segments of bars exiting from the shearing cycle. 
     According to a variant, the magnetic portion comprises an electromagnet able to be selectively activated and/or adjusted, according to the different operating steps and/or types of metal bars. 
     According to another variant, the magnetic portion comprises a permanent magnet. 
     According to a variant, the butting member is selectively mobile with respect to the shearing unit, in a direction substantially parallel to the longitudinal axis of the bars, so as to function as a thruster too, acting on the tail ends of the metal bars, to take them toward and beyond the shearing unit. 
     In this solution, the metal bars subjected to longitudinal thrust are substantially prevented from making uncontrolled reciprocal longitudinal movements due to inertia, since they all remain in contact with the butting member, due to the action of magnetic attraction effected by the magnetic portion. 
     Therefore, there is a substantial guarantee that the movement and shearing effected are substantially equivalent for all the metal bars fed, giving the advantage of uniformity and accuracy of the segments, and the length of the latter can be defined only by controlling the advance of the butting member. 
     According to a variant, the alignment unit comprises a butting member and a thruster member operatively independent of each other and able to act on the tail ends of the metal bars at different times and in different ways. 
     According to another variant, the butting member in its operating thrust condition, or the thruster member when provided independent, acts until it takes the tail ends to a predetermined initial distance from the shearing unit. This distance is advantageously a multiple of the measurement of the individual segments into which the metal bars are to be divided. 
     In this way the off-cuts, that is, the part of the bar that exceeds the multiple of the length of the individual segment, are generated in correspondence with the leading ends of the bars and no longer in correspondence with the tail ends, facilitating the discharge of the off-cuts. 
     According to another variant, downstream of the shearing unit there is a distribution means that selectively directs the segments sheared into specific containing baskets and/or toward one or more automatic working machines. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       These and other characteristics of the present invention will become apparent from the following description of a preferential form of embodiment, given as a non-restrictive example with reference to the attached drawings wherein: 
         FIG. 1  is a schematic plane view of an apparatus to feed and shear metal bars according to the present invention, in a first operating step; 
         FIG. 2  is a schematic plane view of the apparatus in  FIG. 1 , in a second operating step; 
         FIG. 3  is a schematic plane view of the apparatus in  FIG. 1 , in a third operating step; 
         FIG. 4  is a schematic plane view of the apparatus in  FIG. 1 , in a fourth operating step; 
         FIG. 5  is a schematic plane view of the apparatus in  FIG. 1 , in a fifth operating step; 
         FIG. 6  is a schematic plane view of the apparatus in  FIG. 1 , in a sixth operating step; 
         FIG. 7  is a schematic plane view of the apparatus in  FIG. 1 , in a seventh operating step; 
         FIG. 8  is a schematic lateral view of an enlarged detail of the apparatus in  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With reference to the attached drawings, an apparatus  10  according to the present invention is configured to feed and shear, substantially continuously, a plurality of metal bars  11  into segments  12  of a desired length, and to feed them to one or more automatic machines, of a known type and not shown here, for example a stirrup-making machine, a caging machine, a store or other analogous or comparable machine. 
     In particular, the apparatus  10  according to the invention is suitable to pick up the metal bars  11  from a feed store, also of a known type and not shown here, in which the latter are grouped together, according to their diameter, in a plurality of homogeneous bundles, for example disposed adjacent to each other. 
     The apparatus  10  according to the invention comprises in sequence a feed unit  13  that allows to feed the metal bars  11 , an alignment and translation unit  15  that allows to align the metal bars  11  fed by the feed unit  13  and moves them in a guided manner toward a predefined shearing axis “C”, and shears  16  that make the segments  12  from the metal bars  11  moved by the feed unit  13 . 
     The shears  16  are of a substantially known type and will not be described in detail here; they are able to shear the bars  11  into segments  12  along the shearing axis “C”. 
     In particular, the feed unit  13  comprises a plane  14  provided with rollers, chains or other translation means, able to act longitudinally on the bars  11  so as to take them into correspondence with the alignment and translation unit  15 . 
     The plane  14  also comprises, pivoted in correspondence with one flank facing toward the alignment and translation unit  15 , a plurality of stopping levers  18  which selectively allow to hold the metal bars  11  temporarily on the plane  14 , or to feed them to the alignment and translation unit  15 . 
     The alignment and translation unit  15  comprises a butting member  17  positioned substantially parallel to the feed unit  13 , and suitable to cooperate with the tail ends  11   a  of the metal bars  11  picked up from the feed store, so as to align the metal bars  11  longitudinally with respect to the tail ends  11   a,  and thus carry out a tail-wise butting of the bars  11 . 
     In this case, the butting member  17  comprises an abutment wall  20  against which the tail ends  11   a  of the metal bars  11  rest, reciprocally aligned, thus carrying out a tail-wise butting of the bars  11 . 
     The abutment wall  20  comprises an abutment surface  20   a,  on which a magnetic portion  19  is provided, facing toward the tail ends  11   a  of the metal bars  11 . 
     In this way, the tail ends  11   a  of the metal bars  11  are attracted into contact with the abutment surface  20   a  by the force of magnetic attraction generated by the magnetic portion  19 , and then all held against the abutment wall  20 , to be uniformly butted with respect to the relative tail ends  11   a.    
     In this case, the magnetic portion  19  comprises one or more electromagnets, of a substantially known type, which are able to be selectively activated and modulated in order to drive/regulate the magnetic attraction on the tail ends  11   a  of the metal bars  11 . 
     According to a variant, the magnetic portion  19  comprises one or more permanent magnets, each generating a determinate force of magnetic attraction. 
     The abutment wall  20  is selectively mobile toward the shearing axis “C”, so as to progressively thrust the metal bars  11 , as will be described in more detail hereafter, into association with the shears  16  and, at the same time, keep them butted tail-wise by means of the action of the magnetic portion  19 . 
     In this case the abutment wall  20  is associated at the rear with a thruster member  21  disposed substantially parallel to the direction of feed of the bars  11 , and able to thrust selectively the abutment wall  20  to move the metal bars  11  toward the shears  16 . 
     A position transducer  30  is associated with the thruster member  21 , and allows to verify the entity of the linear advance of the metal bars  11  held by the magnetic portion  19  of the abutment wall  20 , and to easily calculate the distance “D” of the abutment wall  20  with respect to the shears  16 . 
     The alignment and translation unit  15  comprises a first transport member  23  disposed downstream of the abutment wall  20  and in line with and upstream of the shears  16 , and a second transport member  25  disposed downstream and in line with the shears  16 . 
     In this case, both the first transport member  23  and the second transport member  25  substantially consist of a rollerway  24 , on which the metal bars  11  slide, moved by the moving abutment wall  20 . 
     The first transport member  23  also comprises a lateral shoulder  31 , able to hold the metal bars  11  laterally before shearing. 
     According to a variant, one or both of the first transport member  23  and the second transport member  25  substantially consists of a driven conveyor belt provided externally with a plurality of magnetic elements disposed transverse to the metal bars  11 , so as to effect a controlled transport of the latter. 
     The alignment and translation unit  15  also comprises a distribution member  26 , associated downstream and in parallel with the second transport member  25 , and able to direct the segments of bar  12  toward relative automatic machines, stores or other users. 
     In this case the distribution member  26  comprises a rollerway disposed and configured so as to move the segments  12  parallel to the axis of movement of the metal bars  11  along the rollerway  24 , that is, forward or backward, with respect to the normal direction of feed of the metal bars  11 . 
     The method according to the present invention to feed and shear segments  12  starting from metal bars  11  with the apparatus  10  as described heretofore is as follows. 
     With reference to  FIGS. 1 to 7 , in a first step of the method according to the present invention, a plurality of metal bars  11  are fed from the feed store and, once on the plane  14 , are fed toward the alignment and translation unit  15  by means of the stopping levers  18  ( FIG. 1 ). 
     The metal bars  11  are then positioned on the first transport member  23  close to the lateral shoulder  31 , and the abutment wall  20  is made to advance by the thruster member  21  until it contacts the tail ends  11   a  of the metal bars  11 . 
     Thanks to the action of the magnetic portion  19 , all the tail ends  11   a  of the metal bars  11  move into contact with the abutment surface  20   a  of the abutment wall  20  ( FIG. 2 ). 
     Simultaneously, the stopping levers  18  are raised, and a new plurality of metal bars  11  are fed onto the plane  14 . 
     Subsequently the thruster member  21  is activated, which thrusts the metal bars  11  longitudinally by means of the abutment wall  20  until it takes their tail ends  11   a  to a determinate distance “D” from the shears  16 . The distance D is chosen as a function of the initial length of the metal bars  11  and the number and length of the individual segments  12  to be made ( FIGS. 3 and 8 ). 
     For example, if we want to make four segments  12  of about 3 meters each, from metal bars  11  of about 13 meters, the distance D is set at about 12 meters. In this way, the metal bars  11  pass beyond the shears  16  with their leading ends, defining downstream of the shears  16  relative off-cuts  12   a  with a length of about 1 meter. 
     The off-cuts  12   a  are thus picked up by the second transport member  25  and discharged by the latter to a zone immediately downstream of the shears  16 . 
     At this point the abutment wall  20  keeps the metal bars  11  to be sheared aligned and moves them, making them advance progressively by a determinate amount. 
     The amount the metal bars  11  are fed toward the shears  16  is commanded by the thruster member  21  and controlled by the position transducer  30 , thus guaranteeing the uniform shearing of the various segments  12 . 
     The second transport member  25  moves the sheared segments  12  in a coordinated manner. 
     Subsequently, as shown in sequence in  FIGS. 5 ,  6  and  7 , the sheared segments  12  are alternately moved by the distribution member  26 , forward and backward with respect to the feed imparted to them by the second transport member  25 . 
     At the same time as the last cut is made to the metal bars  11 , the stopping levers  18  are lowered, allowing new metal bars  11  butted tail-wise to be positioned on the first transport member  23  and immediately start a new shearing and feeding cycle. 
     It is clear however that modifications and/or additions of parts may be made to the apparatus  10  as described heretofore, without departing from the field and scope of the present invention. 
     It is also clear that, although the present invention has been described with reference to specific examples, a person of skill in the art shall certainly be able to achieve many other equivalent forms of apparatus to feed and shear metal bars, and relative method, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.