Abstract:
An apparatus for feeding stapling elements grouped in sets to a stapling machine which is suitable to insert the elements astride the joint of strips arranged at an angle in order to provide perimetric frames, supporting frames and the like, comprising a magazine which is composed of at least one inclined channel suitable to accommodate a plurality of aligned sets and having a downward outlet for the sets, means for individually releasing the sets from the at least one channel through the outlet, a holder which comprises at least one seat arranged below the outlet of the at least one channel, actuators for actuating the holder between a position for receiving a set from the at least one channel in the at least one seat and a position for positioning the set with respect to the stapling machine so as to align the punch of the machine with the stapling elements to be inserted.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to an apparatus for feeding stapling elements to a stapling machine suitable to join strips at an angle, in order to form perimetric frames, supporting frames and the like. 
     In stapling machines for forming perimetric frames and supporting frames, the strips are arranged at an angle and are joined one another by means of stapling elements which are constituted by staples, contoured plates and the like generically known as metal stapling members or staples. 
     The metal stapling members or staples are grouped so as to form a set which is accommodated in a holder. By means of an appropriately provided pusher which acts on the set, the stapling members are pushed out of the holder and arranged above a punch which is actuated by a pneumatic cylinder and inserts them astride the connecting line of two strips arranged at an angle. 
     It has been observed that the capacity of said holders is insufficient, and it is therefore necessary to frequently perform refilling, thereby interrupting the production cycle. 
     SUMMARY OF THE INVENTION 
     The aim of the present invention is to provide an apparatus which allows to feed the metallic stapling members to the stapling machine so as to ensure long operating periods without refilling. 
     Within the scope of this aim, an object of the present invention is to provide an apparatus which allows to feed metallic stapling members of different kinds in terms of dimensions and format, selected by the apparatus according to the type being required. 
     This aim and this object are achieved with an apparatus whose characteristics are defined in the appended claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Further characteristics and advantages will become better apparent from the following description of an embodiment in which the apparatus is combined with a frame assembling machine. 
     In the accompanying drawings: 
     FIG. 1 is a perspective view of a frame assembling machine provided with the apparatus according to the invention; 
     FIG. 2 is a sectional view of the assembling machine and of the apparatus; 
     FIG. 3 is a perspective view of the apparatus; 
     FIG. 4 is a top perspective view of the internal mechanism of the apparatus; 
     FIG. 5 is a bottom perspective view of the mechanism shown in FIG. 4; 
     FIG. 6 is a sectional view of a channel for conveying the stapling members toward the stapling machine; 
     FIG. 7 is an enlarged-scale view of the detail enclosed in the circle of FIG. 6; 
     FIG. 8 is a schematic plan view of the means for positioning the metal stapling members on the stapling machine; 
     FIG. 9 is a schematic sectional view, taken along the line IX—IX of FIG.  8 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to the figures, the reference letter A generally designates an assembling machine comprising a footing  1  provided with a worktable  2  on which there is an L-shaped element  3  for arranging at right angles two strips L 1  and L 2  in order to form a frame. The ends of the strips L 1  and L 2  are cut at 45° and are arranged side by side on a coupling plane which divides in half the angle enclosed by the two strips. 
     Two parallel bars  4  are fixed under the worktable  2 , between two shoulders  1   a  and  1   b  rigidly coupled to the sides of the footing  1 , and constitute guides for the sliding of a carriage  5  which can be positioned along the guides by means of a reversible motor  6 . The motor  6  is fixed to the footing  1 , and its output shaft  7  is threaded in order to engage by screwing in a bracket  8  of the carriage  5 . 
     The shaft  7 , turned by the motor  6 , allows to move the carriage  5  in both directions X—X. 
     Below the carriage  5  there is a stapling machine or stapling head of a known type, generally designated by the reference numeral  9 . 
     Said head  9  comprises a cylinder  10  having a vertical axis and inside which a piston  12  can move; said piston is provided with a stem  13  which protrudes upwards and ends with a striking punch  14  for firing the metallic stapling members, particularly for joining at an angle the two strips L 1 , L 2  that form the frame. 
     The striking punch  14  is guided in a firing channel which lies within the head  15  of the stapling machine  9 . The head  15  is slideable along a through slot  16  of the worktable  2  which is parallel to the direction X—X and is preset to receive and position, in alignment with the punch  14 , the metallic stapling members for joining the strips. The L-shaped element  3  is fixed on the worktable  2  so that the coupling plane of the strips L 1  and L 2  in abutment against the L-shaped element is aligned with the slot  16 . 
     A fluid-actuated or pneumatic actuator  17  is further installed below the worktable  2  and is composed of a cylinder  18  fixed below the worktable  2  and in which a piston  19  slides along the direction Z—Z. The stem of the piston  19  acts on a pair of columns  20  which rise above the worktable  2  and support a device for locking the strips on the worktable  2 , generally designated by the reference numeral  21  and composed of an arm  22  which cantilevers out from the top of the column  20  to which it is fixed and includes guiding means for a pair of sliders  23  and  24 . 
     Two fluid-actuated jacks  25  and  26  are fitted on the sliders  23  and  24 ; their stems  27  and  28  protrude downwardly under the arm  22  and support, at their lower end, respective pads  29  and  30 . 
     Respective threaded shafts  31  and  32  are engaged by screwing in the sliders  23  and  24  and can be actuated by a pair of motors  33  and  34  so as to allow the sliders  23  and  24  to move along the respective guides independently of each other. By way of conventional devices for detecting the cross-section of the strips L 1  and L 2  (which are not shown, since they are not pertinent to the present invention), the motors  33  and  34  are actuated so as to move the pads  29  and  30  into the intended positions for locking the strips L 1  and L 2 . At the same time, the motor  6  is actuated so as to move the carriage  5  and therefore the stapling machine  9  into the positions in which the metallic stapling members are to be inserted astride the joint of the strips L 1  and L 2 . 
     The firing channel of the metal stapling members that lies within the head  15  has a cross-section which is complementary to the shape of said stapling members. 
     It is assumed hereinafter that the metallic stapling members are constituted by laminar staples, designated by the reference letter G, having a W-shaped cross-section and being joined so as to form sets S of preset length. The staples G are fed in sets S from a magazine which is described in greater detail hereinafter and is generally designated by the reference letter M. In order to arrange the staples G in the head  15 , such head has, parallel to the firing channel  35  of the punch  14 , two grooves  36  and  37  which are arranged at the sides of the channel  35 . The grooves  36  and  37  have outer walls, with respect to the channel  35 , which converge towards the centerline plane of the head  15 . 
     A slider  38  can further slide on the guides  4 , between the carriage  5  and the shoulder  1   b;  with respect to the carriage  5 , said slider can move by means of a jack  38   a  (see FIG. 5) in which the cylinder is mounted below the carriage  5  and the stem is rigidly coupled below the slider  38 . 
     Two bars  39  are arranged above the slider  38 , are perpendicular to the guides  4  and constitute guides for a sliding block  40 . The sliding block  40  can be positioned along the guides  39  by means of a jack  41  composed of two cylinders arranged in series (see FIG.  8 ), in which the stems are respectively rigidly coupled to the slider  38  and to the sliding block  40  so as to move said sliding block in the direction Y—Y which is perpendicular to the direction X—X of the carriage. 
     Four seats  42 ,  43 ,  44 ,  45  are formed in the sliding block  40 , are open upward and are designed to receive the sets S of stapling members G. Said seats  42 - 45  are shaped complementarily to the set S that they must contain. In particular, the seats  42 - 45  can have a rectangular cross-section which has the same width but increases in height from the seat  42  to the seat  45  so as to allow the insertion therein of sets S composed of stapling members of increasing height. 
     Each seat  42 - 45  (see FIG. 8) has two flat and parallel walls  46  and  47 , which form a channel, and a bottom  48 . At the end that is directed towards the head  15 , the bottom  48  has a recess  49  which is mirror-symmetrical with respect to the channel  35 . The walls  46  and  47  protrude beyond the recess  49 , forming extensions  46   a ,  47   a  which have converging outer faces and ends which are folded towards each other so as to form mutually opposite claw-shaped shoulders  50  and  51 . 
     A flange  52  is rigidly coupled to the sliding block  40 , at the end that lies opposite the recesses  49  (see FIGS.  4  and  5 ), and stapling member pusher elements  53  are fixed to said flange in alignment with the seats  42 - 45 . The stapling member pusher elements  53  are constituted, for example, by pneumatic cylinders which cantilever out from the flange  52  and act on the sets  5  arranged in the seats  42 - 45 , keeping them in abutment against the shoulders  50 ,  51 . 
     In practice, the sliding block  40 , with the seats  42 - 45 , the jack  41  for Y—Y transverse movement and the jack  38   a  for X—X axial movement constitute a holder C which allows to supply the stapling machine  9  with staples G to be fired. 
     In order to supply in turn the holder C with sets S of staples G, there is a magazine, generally designated by the reference letter M, which is composed of an inclined surface  54  being fixed, by means of a bracket  54   a , to the worktable  2  behind the L-shaped element  3 . 
     A plurality of parallel shoulders  55  are arranged on the inclined surface  54  and form multiple channels  56  which are open upwardly. The channels  56  have a bottom  57  spaced from the surface  54 , so as to form an interspace  58  which is connected to a source of compressed air which enters it through an inlet  59  of the surface  54  in order to facilitate the descent of the sets S. The compressed air exits from the interspace  58  into the channels  56  through a plurality of passages  60  which are orientated towards the descending side of the surface  54 . 
     The lowermost portion of the shoulders  55  and of the inclined surface  54  passes through an opening  61  of the worktable  2  (see FIG.  1 ), so that the lower ends of the channels  56  lie above the seats  42 - 45  of the holder C. 
     The sets S of staples G to be fed into the holder C are deposited in the channels  56 . The sets S are deposited one at a time by means of a singling-out device composed of a first series of retention elements  62  which are arranged at the outlet of the channels  56  and by a second series of locking elements  63  which are spaced from the elements of the first series. The distance of the retention elements  62  from the locking elements  63  is such that when the former release the set that is closest to the outlet of the channels  56 , the second elements lock the immediately subsequent set. 
     As shown more clearly in FIG. 6, the elements  62  and  63  are each constituted by a pneumatic cylinder  64  which has a piston whose stem  65  protrudes in order to lock the set S against the bottom  57  of the channel  56 . 
     The operation of the described apparatus is as follows. 
     Assume an initial situation in which the assembling machine A is in the position shown in FIG. 2, in which the strips L 1  and L 2  arranged at right angles against the L-shaped element  3  are locked by the pads  29  and  30  against the worktable  2  and must be joined one another by a set of three staples G which are inserted in succession astride the coupling line formed by the ends of the strips L 1  and L 2 . 
     Assume, furthermore, that the magazine M and the holder C are empty. 
     First of all, the magazine M is filled by introducing in the channels  56  sets S of staples G having the intended dimensions and shape, according to what is required to ensure a firm coupling of the strips. 
     Rows of sets S thus form in the channels  56  and descend by gravity and due to the action of the compressed air fed through the passages  60 , sliding on the bottoms  57  and stopping against the stems  65  of the retention elements  62 . When the locking elements  63  are activated, the sets S that lie directly adjacent to the sets that abut against the stems of the elements  62  are locked. 
     At this point, by actuating the jacks  39  and  41 , the holder C is moved into the position in which the seats  42 - 45  are aligned with the channels  56 . 
     By raising the stems  65  of the retention elements  62 , the lowermost sets S, i.e., the ones located downstream of the locking elements  63 , are conveyed into the seats  42 - 45  by gravity and due to the compressed air, which forms a cushion under said sets which allows sliding. 
     At this point the pushers  53  intervene and push the sets S into abutment against the shoulders  50  and  51 . 
     Then, by actuating the jacks  38   a  and  41 , the seat that contains the staples G to be used to join the strips L 1  and L 2  is positioned in front of the channel  35  of the head  15 . Finally, by making the sliding block  40  move in the direction X—X by means of the jack  38   a , the sliding block  40  is moved toward the firing head  15 , causing the engagement of the extensions  46   a ,  47   a  in the slots  36 ,  37  of the head  15  and the centering of the recess  49  against the channel  35  in order to form the guiding channel for the firing punch  14 . 
     By keeping the jack  38   a  activated so as to retain the slider  38  adjacent to the carriage  5  and therefore keep the extensions  46   a  and  47   a  engaged in the slots  36  and  37 , the stapling machine  9  is moved in order to place the punch  14  at the point of the joint of the strips where the first staple G of the intended set of three is to be inserted. 
     The movement of the stapling machine  9  is controlled by the motor  6 , which acts on the carriage  5  on which the machine is mounted. It should be noted that during the strokes of the carriage  5  along the guides  4 , the head  15  of the stapling machine  9  slides along the slot  16 . 
     Once the first staple G has been inserted, the head  15  is moved, by way of successive movements of the carriage  5 , to the points where the other two staples G are to be inserted. 
     The strips L 1  and L 2  thus joined are released by lifting the pads  23  and  24 . The operating steps follow each other in the same manner for joining two successive strips. 
     A fundamental prerogative of the described apparatus is the fact that the magazine M can contain sets S of staples G having different shapes and dimensions and which, transferred into the seats  42 - 45  of the holder C, can provide a range of choice of the staples according to the characteristics of the strips to be joined. 
     The described machine is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims. 
     In particular, the number of seats of the holder C and of the channels of the magazine M can vary according to requirements. Furthermore, the movements of the carriage  5 , of the slider  38  and of the sliding block  40  can be controlled automatically on the basis of parameters obtained by reading the dimensional characteristics of the strips. 
     The disclosures in Italian Patent Application No. BO2000A000061 from which this application claims priority are incorporated herein by reference.