Abstract:
A device for transferring bars from a magazine into the guiding channel of a feeder for feeding a machine tool, the magazine comprising an inclined surface for supporting the bars having a side for unloading bars into the channel, adjusters for adjusting inclination of the supporting surface, elements for retaining bars on the surface, and bar pickers which are actuated to disengage the lowermost bar from the retention elements and move it to a level for falling into the channel, and actuators for simultaneously actuating the adjusters and the retention elements for inclination and position adjustments suitable to accommodate variations in the diameter of the bars to be transferred.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to a device for transferring bars from a magazine into the guiding channel of a feeder for feeding a machine tool.  
           [0002]    It is known that a bar magazine for the above indicated purpose comprises an inclined surface on which the bars that arrive from an appropriately provided feeder are deposited and arranged next to one another.  
           [0003]    Means are associated with the inclined surface which separate the last bar (the lowermost one) and transfer it into the guiding channel, along which appropriate pushers make it advance toward the machine tool.  
           [0004]    However, known magazines do not allow rapid adjustment of the means designed to individually pick and unload the bars into the guiding channel according to their diameter, and therefore when it is necessary to feed bars of different diameters it is necessary to perform rather labor-intensive operations that can be carried out by specialized personnel.  
         SUMMARY OF THE INVENTION  
         [0005]    The aim of the present invention is therefore to provide a device that allows to act simultaneously on the means for individually picking and unloading the bars into the guiding channel in order to modify their configuration and parameters according to the diameter of the bars.  
           [0006]    Within this aim, an object of the present invention is to provide a device that is constructively simple and therefore inexpensive and reliable in operation, also in view of the rough treatment to which such devices are subjected due to the weight of the bars and to the mechanical stresses.  
           [0007]    This aim and this and other objects which will become better apparent hereinafter are achieved with a device for transferring bars from a magazine into the guiding channel of a feeder for feeding a machine tool, said magazine comprising an inclined surface for supporting the bars which has a side for unloading the bars into said channel, characterized in that it comprises means for adjusting the inclination of said supporting surface, elements for retaining the bars on said surface which are suitable to affect the lowermost bar, and means for individually picking said bars which are actuated so as to disengage said lowermost bar from said retention elements and move it to a level for falling into said channel, means being provided for simultaneously actuating said adjustment means and said retention elements so as to vary the inclination of the supporting surface and the position of the retention elements in order to adapt them to the variation in the diameter of the bars to be transferred. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]    Further characteristics and advantages of the present invention will become better apparent from the following description of a preferred embodiment thereof, illustrated only by way of non-limitative example in the accompanying drawings, wherein:  
         [0009]    [0009]FIG. 1 is a perspective view of a bar feeder;  
         [0010]    [0010]FIG. 2 is a plan view of the feeder of FIG. 1;  
         [0011]    [0011]FIG. 3 is a side view, taken along the line III-III of FIG. 2, of the feeder preset for large-diameter bars;  
         [0012]    [0012]FIG. 3 a  is an enlarged view of a detail of the feeder as shown in FIG. 3;  
         [0013]    [0013]FIGS. 4 and 5 are views of the means for individually picking the bars in two operating positions;  
         [0014]    [0014]FIG. 6 is a side view of the feeder, preset for small-diameter bars;  
         [0015]    [0015]FIG. 6 a  is an enlarged view of a detail of the feeder as shown in FIG. 6;  
         [0016]    [0016]FIG. 7 is a partially exploded perspective view of a different embodiment of inclination adjustment means. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0017]    With reference to FIGS.  1  to  3 , the reference numeral  1  designates a generic feeder, which comprises a U-shaped housing  2  mounted on a footing  3 . The housing delimits a compartment which is closed by a cover  4  and accommodates the bar guiding channel  5  and the other elements for the advancement of the bars toward a machine tool. In the figures, the bar advancement elements are not shown, since they are beyond the scope of the present invention.  
         [0018]    The bar guiding channel  5  is constituted by a plurality of rollers  6 , rotatably supported in box-like elements  7  which have a U-shaped cross-section; a wing  8  is rigidly coupled to one edge of said box-like elements and acts as a chute for conveying the bars into the guiding channel  5 .  
         [0019]    The rollers  6  are shaped like an hourglass composed of two opposite frustums, which are tangent to two imaginary planes that give the guiding channel  5  a V-shaped cross-section, one of said planes being co-planar with respect to the chute  8 .  
         [0020]    The box-like elements  7  and the rollers  6  supported therein constitute modules  9 , which are fixed on a longitudinal member  10  accommodated in the housing  2  and are mutually spaced by gaps  11 .  
         [0021]    Brackets  12  are fixed to the longitudinal member  10 , and respective supports  13  are fixed to the top of said brackets. An articulation shaft  14  is supported within the supports  13  and allows the articulation of a shelf  15 , which cantilevers out laterally from the housing  2  and defines a supporting surface  16  for a plurality of bars B to be transferred into the guiding channel  5 .  
         [0022]    Prism-shaped blocks  17  are fixed below the supporting surface  16  and are elongated at right angles to the shaft  14 .  
         [0023]    Two mushroom-shaped pins  18  protrude from a lateral face of said blocks  17  and slidingly engage a pair of slots  19 , which are parallel to the surface  16  and are formed on sliders  20  which are kept adjacent to the blocks  17  by the heads of the pins  18 .  
         [0024]    The sliders  20  are aligned with the gaps  11  and comprise an extension  21 , which is raised with respect to the surface  16  and is guided through slots  22  formed toward the side of the surface that is adjacent to the guiding channel that constitutes the side for the exit or unloading of the bars with respect to the surface  16  into the channel  5 .  
         [0025]    The extensions  21  constitute bar retaining elements and are shaped so that their upper edge defines a shoulder  23  for retaining the bars B that descend along the surface  16  and a bridge  24  that lies above the edge of the chute  8  and allows to unload the bars into the channel  5 . The edge of the shoulder  23  is rounded in order to blend with the edge of the bridge  24 .  
         [0026]    The sliders  20  are provided, on one side, with a pin  25 , which engages between the prongs of a respective fork  26 .  
         [0027]    The forks  26  are keyed on a rod  27 , which is parallel to the shaft  14  and is rotatably supported within ribs  27   a  are fixed below the surface  16 .  
         [0028]    A radial lever is centrally rigidly coupled to the rod  27  and is constituted by an additional fork  28  (see FIG. 2), to which the end of a stem  29  is connected; said stem  29  is perpendicular to the shaft  14 . The stem  29  is guided in supports  30 , so as to slide axially without turning.  
         [0029]    A tubular screw  31  is coaxial to the stem  29 , is provided with an inner thread and an outer thread, and can rotate within supports  32 .  
         [0030]    A threaded end of the stem  29  is screwed into the inner thread, and a female-thread sliding block  33  is screwed onto the outer thread and slides between a pair of guides  34 , which are fixed below the surface  16 . The inner and outer threads of the screw are provided, so that when the screw is turned the sliding block  33  and the stem  29  always move in opposite directions.  
         [0031]    A strut  35  is articulated by way of its tip to the sliding block  33  and is articulated on the footing  3  by means of its lower end.  
         [0032]    The screw  31  continues with a portion between the supports  32  and  30 , and a first bevel gear  36  is keyed on said portion and meshes with a second bevel gear  37 . Said bevel gear  37  is keyed on a shaft  28 , which is supported below the surface  16  parallel to the rod  27  and can be actuated by means of a crank  39 .  
         [0033]    Inclination adjustment means for the surface  16  are thus provided.  
         [0034]    When, by actuating the crank  39 , the sliding block  33  and the stem  29  perform a translational motion toward each other, the strut  35  rotates toward a more vertical position, causing a steeper inclination of the surface  16 . At the same time, the sliders  20  are retracted with respect to the guiding channel  5 , in order to allow the adaptation of an individual picking device to act on bars B having a different diameter.  
         [0035]    The individual picking device has picking means constituted by a plurality of levers  40 , which are rotationally rigidly coupled to the shaft  14  at the slots  22 .  
         [0036]    The levers  40  are shaped like sectors, with a first arm having an edge  41  shaped like an arc that is concentric with respect to the shaft  14  and an edge  42  which is straight and, in an angular position of the lever, is co-planar with respect to the surface  16 .  
         [0037]    One of the levers  40  comprises a second arm  43 , which protrudes downward and ends with a roller  44 , which engages in the slot  45  of a cam  46  actuated by an actuator (not shown) in an axial direction, i.e., parallel to the shaft  14 . The slot  45  is shaped so that by actuating the cam  46  the arm  43  performs an angular stroke which determines the oscillation of the levers  40  between a position in which the edge  42  is co-planar to the surface  16  and a position in which said edge  42  has substantially moved beyond the shoulder  23  of the sliders  20 .  
         [0038]    From the above description it is evident (see FIG. 3) that in order to transfer large-diameter bars B from the magazine into the guiding channel, the shelf  15  is arranged so as to have a small angle with respect to the horizontal. In this manner, the component of the weight of the bars that acts against the bar B 1  to be transferred into the guiding channel, i.e., against the lowermost bar, which abuts against the shoulder  23  of the sliders  20 , is reduced.  
         [0039]    At the same time, the sliders  20  are in a more advanced position, in order to allow the lower bar B 1  to arrange itself on the lever  40  and remain adjacent to the shoulders  23 .  
         [0040]    By activating the cam  46 , the levers  40  perform a rotational angle by means of which the bar B 1  is raised on the edge  24  of the extensions  21 , from which, by gravity or with the aid of pick-up elements, it is inserted in the guiding channel  5 . It should be noted that while the bar B 1  is lifted, the levers  40 , with the arc-like edge  41 , retain the remaining bars, releasing them only when the lever  40  has retracted completely below the surface  16 .  
         [0041]    If the bars to be transferred into the guiding channel  5  have a small diameter (see FIG. 6), the crank  39  is actuated in the direction in which the strut  35  assumes a more vertical position and the sliders assume a more retracted position with respect to the guiding channel. Accordingly, the surface  16  arranges itself at a steeper angle, which facilitates the descent of the bars against the shoulders  23 , while the movement in the opposite direction of said shoulders reduces the length of the edge  41  that protrudes from the shoulders to a length that allows the levers  40  to lift only the lowermost bar.  
         [0042]    It is evident from what has been described that the fundamental prerogative of the present invention is the fact that all the various operations required to adjust the device when the diameter of the bars varies are reduced to the actuation of a single crank and can therefore be performed very easily and rapidly.  
         [0043]    The described device is susceptible of numerous modifications and variations, all of which are within the scope of the same appended claims. For example, instead of the crank it is possible to provide a motor assembly. Likewise, similar synchronized motor assemblies can be used to actuate the sliders  20  and the sliding block  33 .  
         [0044]    Another embodiment of the means for adjusting the supporting surface  16  and the sliders  20  is shown in FIG. 7, in which the elements or parts that are similar to those of the above described example are designated by the same reference numerals.  
         [0045]    The substantial difference with respect to the above described example is the fact that the shaft  38 , actuated by the crank  39 , by means of the pair of bevel gears  36  and  37 , actuates a stem  29 , which has a screw  47  at one end and, at the opposite end, a screw  48  whose thread is opposite to the thread of the screw  47 . The screws  47 ,  48  are engaged in respective female-thread sliding blocks  49 ,  50 , which are prism-shaped and accommodated in seats  51 ,  52  of a fork  53  and, respectively, of a fork-like lever  54 , so as to be unable to rotate about the screws  47 , 48 .  
         [0046]    Furthermore, the sliding blocks  49 ,  50  are each provided with two coaxial pivots  55 ,  56 , which are perpendicular to the screws  47 ,  48  and are articulated in slots  57 ,  58  of the forks  53 ,  54  so as to allow said forks to oscillate about the pivots  55 ,  56 .  
         [0047]    The forks  53 ,  54  are rigidly coupled to the top of the strut  35  and radially coupled to the rod  27 , so that when the crank  39  is actuated, the screws  47 ,  48  move the sliding blocks  49 ,  50  mutually closer or further apart, inclining the surface  16  more or less steeply and moving the sliders  20  forward and backward.  
         [0048]    The disclosures in Italian Patent Application No. B02001A000028 from which this application claims priority are incorporated herein by reference.