Apparatus for producing rectangular frames

Abstract: An apparatus for producing rectangular frames composed of strips (L) joined by joining elements inserted by fixing machines so as to straddle the joints formed by the right-angled mating of the strips, the strips being supplied in the intended sizes by a feeder (1), four fixing machines (30-33) being provided which are arranged on a footing at the corners of an ideal rectangle and are provided with devices (34-35) for arranging the strips along the sides of the rectangle. The apparatus comprises at least one working assembly (40,41) for picking up in succession the strips at the output of the feeder (1) and for placing them on the fixing machines (30-33), so that the ends of two contiguous strips are arranged at right angles on each fixing machine, the working assembly comprising a supporting beam (42) for a rail (44) for the horizontal sliding of a carriage (45) which comprises a guide (49) lying at right angles to the rail (44), a slider (51) being slideable on the guide (49) and articulately supporting, about a vertical axis, a strip engagement element (74), actuation elements (80,52,72) for actuating the carriage (45), the slider (51) and the engagement element (74) between a position in which the engagement element (74) picks up, in successive steps, the strips exiting from the feeder (1) and a position in which it deposits the strips so that the opposite ends of each strip lie on a pair of fixing machines (30-33) which are not diagonally opposite, the steps being coordinated so as to form a rectangle of strips resting on the fixing machines (30-33).

Description: The present invention relates to an apparatus for producing rectangular frames. The strips that compose frames are currently assembled by successive handling operations performed by operators who position the strips and connect them by virtue of appropriately provided fixing machines. However, conventional assembly methods are slow, work-intensive and expensive because they require an extensive manual work force. DE-A-2747314 discloses an apparatus for producing rectangular frames as defined in the preamble of claim 1. DE-A-19608844 discloses a handling apparatus. The aim of the present invention is to automate the manufacture of frames starting from strips fed on-line, for example, by a cropping machine which cuts them to size from a single section or by a feeder which removes them from one or more magazines in which said strips are stacked. Within this aim, an object of the present invention is to provide an apparatus which is versatile in use in relation to the possibility to produce frames in different sizes. This and other objects are achieved with an apparatus for producing rectangular frames composed of strips joined by joining elements, as defined in claim 1. Further characteristics and advantages will become better apparent from the description that follows on the basis of the accompanying drawings, wherein, by way of example, Figure 1 is a perspective view of an apparatus according to a first embodiment; Figure 1a is a perspective view of the fixing machines; Figure 2 is a plan view of the apparatus of Figure 1; Figure 3 is a schematic view of a fixing machine; Figures 4 and 5 are two perspective views, taken from opposite sides, of a working assembly of the apparatus; Figures 6 and 7 are two perspective views, taken from opposite sides, of part of the working element of Figures 3 and 4; Figure 8 is a sectional view, taken along the plane VIII-VIII of Figure 7; Figure 9 is a perspective view of a second embodiment of the apparatus; Figures 10 and 11 are two perspective views, taken from opposite sides, of the working element used in the apparatus of Figure 9; Figure 12 is a perspective view of a third embodiment of the apparatus; Figures 13 and 14 are two perspective views, taken from opposite sides, of an auxiliary device used in the apparatus of Figure 13; Figure 15 is a perspective view of a fourth embodiment of the apparatus; Figure 16 is a perspective view of a fixing machine provided with a device for locking a strip thereon; Figure 17 is a plan view of the device; and finally Figures 18 and 19 are two sectional views, taken along the plane XVIII-XVIII of Figure 17, of the device in two different operating situations. With reference to Figures 1 and 2, 1 designates a generic cropping machine, provided with a cutting head 2 which supplies in output strips L which are cut so as to have two opposite ends beveled at 45°. The apparatus 3, by means of which the strips L are assembled so as to form a frame, is associated at the output of the cropping machine 1. The apparatus 3 comprises a prism-shaped footing which is composed of four posts 4 arranged at the corners of a rectangle and connected by cross-members 5, 6 and longitudinal members 7, 8 at the top, by longitudinal members 9, 10 and cross-members 11, 12 halfway along their height, and by a plurality of cross-members 13 which lie between two longitudinal members 14 at the base. Two respective bars 15, 16 are rigidly coupled to the cross-members 11, 12, and two rails 17, 18 are fixed to said bars; four plates 19, 20, 21, 22 for coupling a matching number of supports 23, 24, 25, 26 can be arranged along said rails. The plates 19-22 are connected in pairs by bars 27, 28 which allow to move the plates 19, 20 simultaneously with respect to the plates 21, 22. Respective pairs of bars 29 are guided in each one of the supports 23-26 and protrude with a 45° angle with respect to the rails 17, 18. The bars 29 support, in a cantilevered arrangement, four fixing machines 30, 31, 32, 33 arranged at the corners of an imaginary rectangle. The conventional fixing machines 30-33 are not described in detail except to note (see also Figure 3, which schematically shows a conventional fixing machine) that there is a bracket 34 for supporting the opposite ends of the strips L that will form the frame, an L-shaped element 35 for the abutment and arrangement at 90° on the bracket 34 of the ends that rest thereon, a presser 36 which is guided vertically by means of columns 37 in the bracket 34 and is actuated by a pneumatic actuator 38 in order to clamp the ends arranged against the L-shaped element 34, and a pneumatic actuator 39 which inserts the fixing elements so that they straddle the joints formed between the ends. In order to transfer and position the strips L supplied by the cropping machine 1, above the fixing machines there are two working assemblies, generally designated by the reference numerals 40 and 41, for picking up the strips from the cropping machine and placing them on the fixing machines 30-33. Since said assemblies are identical in a mirror-symmetrical fashion, only one assembly is described hereinafter for the sake of brevity in description. Each assembly comprises (see Figures 4-8) a horizontal beam 42 whose opposite ends are fixed below the cross-members 5 and 6 by virtue of angle elements 43 (see Figure 1). Two parallel rails 44 are fixed to one face of the beam 42, and a carriage 45 is slideable thereon. Said carriage comprises a plate 46, below which a bracket 47 is rigidly coupled; said bracket cantilevers out laterally. Sliding blocks 48 (shown in Figures 4 and 5 but not shown in Figures 6-8) are fixed on the face of the plate 46 that is directed toward the beam 42 and slidingly engage the rails 44. The bracket 47 is provided, in a downward region, with a tubular portion 49 which has a rectangular cross-section and is internally provided with sliding blocks 50 (see Figure 8) for a slider 51. The slider 51 comprises a slideway 52 having a substantially I-shaped cross-section and having, on its lower face, two rails 53 by means of which it slides in the sliding blocks 50. Two clamps 54, 55 are provided at the opposite ends of the upper face of the slideway 52 and fix the opposite ends of a belt 56 actuated by a motor assembly, generally designated by the reference numeral 57. Said assembly comprises two flanges 58, 59 which are fixed at right angles to the bracket 47 and between which there is a box-like body 60 which encloses a cavity 61. The cavity 61 is connected to the cavity 62 formed by the tubular portion 49 through an opening 63. Three pulleys 64, 65, 66 are rotatably supported in the cavity 61, and the belt 56 winds around them: the pulley 64 is keyed to the shaft 67 of a reversible gearmotor 68 which is fitted so as to cantilever out on the flange 59, while the pulleys 65, 66 can rotate freely under the pulley 64 so as to protrude into the cavity 62 with a peripheral sector. The pulleys 65, 66 are arranged, with respect to the pulley 64, so that the belt 56 winds around the pulleys 64-66 so as to follow an omega-shaped path. Accordingly, when the gearmotor 68 is actuated the slider 51 is slideable within the sliding blocks 50 at right angles to the beam 42. When the working assembly is fitted on the beam 42, the carriage 45 is arranged to one side of said beam and the slider 51 has an end which protrudes from the opposite side. An arm 69 is rigidly coupled to said end, lies at right angles to the slider and supports a plate 70. The cylinder of a pneumatic jack 71 is fixed to the center of the plate 70 and a motor 72 is fixed to a block arranged laterally to the plate by means of an angle element. Both the jack 71 and the motor 72 have a vertical axis. The stem of the jack 71 extends downwards below the plate 70 and is rotationally coupled, but can slide axially, in a pulley 73 which is rotatably supported below the plate 70. At its lower end, the stem has an engagement element 74 which comprises a pneumatic actuator 75, which actuates two engagement jaws 76 (see Figure 6) and 77 (see Figure 7) which are shaped so as to engage the sides of a strip L. The output shaft of the motor 72 protrudes below the plate 70 and a driving pulley 78 is keyed thereon. A belt 79 winds around the pulleys 78 and 73, so that by actuating the motor 72 it is possible to turn the stem of the jack 71 and orientate the strip L engaged between the jaws 76, 77. In order to move the carriage 45 along the beam 42, there is a gearmotor 80 (see Figures 4 and 5) which is mounted at one end of the beam. A pulley 81 is keyed to the output shaft of the gearmotor 80, and a belt 82 is wound around it. The belt 82 runs parallel to the beam 42 on the side of the carriage 45 and is closed in a loop around a pulley 83 which is supported by a bracket 84, fixed to the opposite end of the beam 42, which lies opposite the motor 48. The belt 82 comprises a portion which lies between the plate 46 of the carriage 45 and the beam 42 and between the sliding blocks 48 by means of which the carriage is guided on the rails 44. The second portion of the belt 82 is fixed to a clamp 85 rigidly coupled on the front of the plate 46 of the carriage 45. As shown in Figure 2, the two working assemblies 40, 41 are arranged symmetrically with respect to the line P along which the strips L exit from the cropping machine 1. In practice, the apparatus is substantially symmetrical with respect to a vertical plane that passes through the exit line P. The operation of the apparatus is evident from Figures 1 and 2. Any sequence may be used to take the strips L from the cropping machine 1 by means of the working assemblies 40, 41 and transfer and orientate them on the brackets 34 of the fixing machines 30-33 in order to produce a rectangular frame. For example, in said sequence, in a first step a first strip (for example a short strip) may be picked up by a working assembly 40 while the other working assembly 41 is in the standby position. During this first step, the carriage 45 of the first assembly 40 is shifted to the end of the beam 42 that lies proximate to the cropping machine 1. At the same time, the engagement assembly 74 has been turned by the motor 72 so that its jaws 76 and 77 can grip the strip L at the center by descending onto it at the output of the cropping machine through the jack 71. The strip L, after being gripped by the engagement element 74, is then lifted and transferred onto the brackets 34 of two fixing machines. Lifting is performed by the jack 71 and transfer is performed by actuating the motors 68 and 80. If the strip is to be arranged on two fixing machines arranged at right angles to the beams 42, the strip is turned through 90° by means of the motor 72. Once the strip has been positioned above the bracket by the two fixing machines that are provided, said strip is lowered and deposited by the engagement element 74. These operations are repeated alternately with one working assembly 40 or with the other working assembly 41 until all four strips have been arranged so as to form a frame. When all the strips have been positioned, they are locked one another by making the brackets 34 move forwards so as to lock the strips against the L-shaped elements 35 and under the pressers 36; finally, said strips are fixed one another by inserting the fixing elements. It should be noted that the operating steps must be sequenced so that the sliders of the working assemblies 40 and 41 do not interfere with each other along the strip advancement line P. An important advantage of the above apparatus is that it works autonomously, since it is not necessary to feed the strips by means of a cropping machine; they can be taken in the required dimensions from one or more magazines and fed to the apparatus by a conveyor. Another advantage of the disclosed apparatus is the possibility to control the working assemblies with an electronic computer which is capable of harmonizing the movements of the carriages, of the sliders and of the engagement assemblies according to the dimensions of the frame to be obtained. The described apparatus is susceptible of numerous modifications and variations. Figures 9-11 illustrate another embodiment of the pick-up assembly, in which the pulley 64 is rotationally rigidly coupled to, but is slideable axially on, a shaft 86 lying parallel to the beam 42. The shaft 86 is rotatably supported in brackets 87, 88 rigidly coupled to the beam 42 and is actuated by a motor 89 coupled to the bracket 88 by means of a flange. Figures 12-14 illustrate another embodiment of the apparatus of Figure 9-11, in which the strips are transferred from the cropping machine 1 to the pick-and-place assemblies 40, 41 by means of an auxiliary device generally designated by the reference numeral 90. Said device 90 comprises a base 91 which is fixed to the worktable at the output of the cropping machine 1 and a block 92 which is fixed on a crossmember 93 that connects two posts 4 of the footing. The opposite ends of two parallel bars 95, which are also parallel to the output line P, are rigidly coupled in the block 92 and in an additional block 94 fixed above the base 91, and a carriage 96 is slideable on said bars. The carriage 96 is provided with a strip engagement element 97 similar to the one designated above by the reference numeral 74 and composed of a fixed jaw 98, which is rigidly coupled to the carriage 96, and by a jaw 99 which is movable with respect to the fixed jaw 98 and is actuated by a pneumatic actuator 100. A fork 101 is rigidly coupled to the block 92, and a pulley 102 is rotatably supported in said fork. A belt 103 is wound around the pulley 102, is parallel to the bars 95 and is closed in a loop around a driving pulley 104 which is rotatable in a support 106 which is fixed to the base 91 and is actuated by a reversible motor 105. The upper and lower portions of the belt 103 lie above and below the blocks 92 and 94 and the carriage 96, while the upper portion is engaged, by means of a clamp 107, with the carriage 96. As clearly shown, the carriage 96 is moved, by means of the motor 106, from a position in which the engagement element 97 grips a strip at the output of the cropping machine 1 and a position in which the gripped strip is delivered alternately to the grip elements of the working assemblies 40 and 41. The apparatus shown in Figure 12 is the same one shown in Figure 9 and the working assemblies are of the type shown in Figures 10 and 11. It is evident that the working assemblies can be replaced with the ones shown in Figures 4-8. Finally, Figure 15 illustrates another embodiment of the apparatus, in which the frame forming strips are taken from two cropping machines 1 and 108, a working assembly 109, 110 being associated with each one of said machines. Each assembly comprises two grip elements 111, 112 supported by sliders 113, 114 which are slideable on carriages 115, 116 and are moved along a beam 117 as described above in relation to Figures 10 and 11. The grip element 111, 112 of each assembly take two strips every time from the two cropping machines 1 and 108, so as to halve the time required to position the strips on the fixing machines and to prepare the frame. It should be noted that the strips L have an indent for forming the seat which receives the glass of the frame and an optional rear closure panel. Said indent may cause strip stability problems when the engagement elements 74 deposit said strips on the brackets 34 of the fixing machines 30-33. In order to prevent the strips L from tipping over laterally once they are rested on the brackets 34, on each bracket there is a device which locks a strip against the L-shaped element 35. With reference to Figures 16-19, said device, generally designated by the reference numeral 118, comprises a prism-shaped case 119 which is fixed in a recess 120 (see Figure 16) of the bracket 34 laterally to the L-shaped element 35, so that it has an upper face 121 which is co-planar to the plane of the bracket. The case 119 encloses a compartment 122 in which there are guides 123 for a slider 124 which can be actuated by means of a pneumatic actuator 125 associated with the case 119 and having a stem 126 rigidly coupled to the slider 124 by a key 127. The slider 124 has a seat 128 in which a lever 129 is articulated in a rocker-like fashion; said lever is actuated so as to turn by a spring 130. Thanks to the spring 130, one arm of the lever 129 protrudes from the case 119 through a slot 131 formed in the upper face of the case. The extent of the protrusion of the arm of the lever from the slot 131 is set by the abutment of the other arm of the lever against the bottom of the seat 128. The operation of the described device 118 is as follows. After the strip L, picked up by the assembly 74, has been arranged on the bracket 34 against the L-shaped element 35, and before it is released by the jaws 75 and 76, the actuator 125 moves the slider 124 in the direction along which the lever 129 locks the strip L against the L-shaped element 35, as shown in Figure 18. Once the strip joining operations have been completed, the slider 124 is moved away and the lever 129 is retracted into the seat 128 by abutment on a pin 132 arranged at the end of the slot 131. The retraction of all the levers 129 into the respective seats 128 allows the completed frame to avoid interfering with said levers during the removal operations, which are normally performed by diagonally spacing apart the fixing machines 30-33, so that the completed frame can descend onto an underlying removal conveyor of the belt type (see Figures 1 and 2). The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims. All the details may furthermore be replaced with other technically equivalent elements. In practice, the materials used, so long as they are compatible with the contingent use, as well as the dimensions, may be any according to requirements. The disclosures in Italian Patent Application No. BO99A000458 from which this application claims priority are incorporated herein by reference. Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the scope of each element identified by way of example by such reference signs.

Claims: An apparatus for producing rectangular frames composed of strips (L) joined by joining elements inserted by fixing machines so as to straddle the joints formed by the right-angled mating of said strips, said strips being supplied in the intended sizes by a feeder (1), four fixing machines (30-33) being provided which are arranged on a footing at the corners of an ideal rectangle and are provided with means (34, 35) for arranging said strips along the sides of said rectangle, characterized in that it comprises at least one working assembly (40, 41) for automatically picking up in succession said strips at the output of said feeder (1) and for placing them on said fixing machines (30-33), so that the ends of two contiguous strips are arranged at right angles on each fixing machine, said working assembly (40, 41) comprising a rail (44), a carriage (45), a supporting beam (42) for the rail (44) for the horizontal sliding of the carriage (45), the latter comprising a guide (49) lying at right angles to said rail, a slider (51) being slideable along said guide so as to slide transversely with respect to the sliding of said carriage and said guide (49) on said rail, said slider articulately supporting, about a vertical axis, a strip engagement element (74), actuation means (80, 52, 72) for actuating said carriage (45), said slider (51) and said engagement element (74) between a position in which said engagement element picks up, in successive steps, the strips (L) that exit from said feeder and a position in which it deposits said strips (L) so that the opposite ends of each strip lie on a pair of fixing machines (30-33) which are not diagonally opposite, said steps being coordinated so as to form a rectangle of strips resting on said fixing machines. The apparatus according to claim 1, characterized in that said actuation means for actuating said carriage comprise a belt (82) which is closed in a loop around two pulleys (81, 82) which are supported on said beam (42) at the opposite ends of said rail (44) and actuated by a motor (80), said carriage (45) being coupled to a portion of said belt. The apparatus according to claim 1 or 2, characterized in that a pneumatic jack and a motor are supported on said slider (51) and both have a vertical axis, said jack (71) having a stem which protrudes downwards and is rotationally coupled, but axially slideable, with respect to a pulley (73) which is rotatably supported on said slider and is actuated by said motor (72) by means of a belt (79) which is wound around it and on a pulley (78) which is keyed to the output shaft of said motor, an engagement element (74) being supported at the lower end of said stem. The apparatus according to one of the preceding claims 1 to 3, characterized in that said engagement element (74) comprises an actuator supported at the lower end of said stem and actuates two jaws (76) for engaging said strip (L). The apparatus according to one of claims 1 to 4, characterized in that said actuation means for actuating said slider (51) comprise a belt (56) whose opposite ends are fixed to said slider and run around two idler pulleys (65, 66) and a driving pulley (64) supported on said carriage (45) and arranged so as to guide said belt along a substantially omega-shaped path, said driving pulley (64) being keyed on the output shaft (67) of a reversible motor (68) which is mounted on said carriage (45). The apparatus according to one of claims 1 to 4, characterized in that said actuation means for actuating said slider (51) comprise a belt (56) whose opposite ends are fixed to said slider and run around two idler pulleys (65, 66) and a driving pulley (64) supported on said carriage (45) and arranged so as to guide said belt along a substantially omega-shaped path, said driving pulley (64) being rotationally rigidly coupled, but axially slideable, with respect to a shaft (86) supported on said beam (42) parallel to said rail (44) and actuated by a reversible motor (81) mounted on said rail. The apparatus according to one of the preceding claims, characterized in that it comprises two working assemblies (40, 41) which cooperate so as to alternately pick up the strips at the output of said feeder and position them on said fixing machines. The apparatus according to one of the preceding claims, characterized in that it comprises a first pair of working assemblies which cooperate so as to alternately pick up the strips at the output of a first feeder and position them on a first pair of fixing machines, and a second pair of working assemblies which cooperate so as to alternately pick up the strips at the output of a second feeder and position them on a second pair of fixing machines. The apparatus according to one of the preceding claims, characterized in that said feeder comprises a cropping machine. The apparatus according to one of the preceding claims, characterized in that the assemblies for actuating said slider, said carriage and said engagement assembly are controlled by an electronic computer which is adapted to adjust their movements according to the dimensions of the frame to be obtained. The apparatus according to one of the preceding claims, characterized in that said means for arranging said strips at right angles comprise a bracket (34) provided with an L-shaped element (35) for the abutment of the ends of said pair of strips, a device (118) being provided on said bracket in order to lock a strip against said L-shaped element. The apparatus according to claim 11, characterized in that said device (118) comprises a prism-shaped case (119) fixed on said bracket laterally to said L-shaped element (35), said case enclosing a compartment (122) in which a slider (124) is slideable which can be actuated by means of an actuator (125) associated with said slider and provided with a stem (126) which is rigidly coupled to said slider, said slider (124) having a seat (128) in which a lever (129) is articulated and is made to turn by elastic means (130) and has an arm which is adapted to protrude from said case (119) through a slot (131) formed in the upper face thereof, said slider (124) being actuatable between two positions, said arm protruding from said slot (131) in one of said positions in order to lock said strip against said L-shaped element (35), and said arm being arranged, in the other position, inside said seat (128) in order to avoid interfering with said strip when the frame is removed.

Inventors: RAFFONI GIUSEPPE, RAFFONI, GIUSEPPE
Applicants: RAFFONI GIUSEPPE, RAFFONI, GIUSEPPE
Application year: 2000
Main classification: B23P19
IPC codes: B21D53, B27F7, B23P19, B27M1