Flying punching machine for extruded section bars

Abstract

 A stepless punching machine for extruded section bars, preferably for roller shutters comprises essentially: moving means (10) of punching means (20) for the section bars including at least a vertical moving punch (21) fit for punching slots in at least one of said section bar; shifting means (30) of the punching means (20), underlying this latter, and fit to realize a stop for said at least one section bar in correspondence of a punching condition of said section bar in which said punching means (20) punch each said section bar keeping a defined pitch; indexer means (40) to which are connected kinematically in input said moving means (10) for driving the motion and in output are connected driving means (50) fit to drive said shifting means (30) at the same moving direction and at a relative speed almost equal to zero as that of the forward moving section bars in correspondence of said punching condition and with contrary direction in correspondence of a not punching condition of said machine (1) in which said section bars move forward through this latter without being punched.

Description

[0001] The present invention relates to machines fit to carry out slots in metallic and non-metallic section bar, in particular the invention refers to a stepless punching machine for extruded section bars for roller shutters.

[0002] There are known "stepless" electromechanical punching machines, in other words, machines for carrying out the slots in the section bars moving continuously, without stopping the section bars to operate the punching. However, these machines have a maximum feeding speed limit of the section bars of 33-34 meters per minute, because in each punching cycle the punches must firstly "follow" the moving section bars, then punch these latter keeping the same feeding speed of the section bar and finally lift the punches from the section bar, always keeping the punches according to the section bar movement.

[0003] Other drawback of these known machines consists in often loosing the phase relationship between the section bar movement and the back-and-forth motions of the punches, especially when it is necessary to modify the punching pitch. This need is also the main cause for the very low punching speed that can be carried out.

[0004] A further drawback is that the punches wear out easily due to their continuous moving in correspondence of the punching and namely the entry to and exit from the slots carried out by them in the continuously moving section bar.

[0005] Besides, these machines use quite complex systems to drive the punches following the moving section bar, so often causing difficult maintenance and high costs.

[0006] They are also known punching machines for section bars operating in an "alternative manner" that punch the slots in correspondence of the section bar stop. These machines are provided with step-by-step moving means of the section bars by means of electric motors, such as brushless electric motors, and a reciprocating motion of punches realized by means of hydraulic cylinders.

[0007] The brushless electric motors and the hydraulic cylinders cause a relevant increase of the realization costs of these punching machines in comparison with the "electromechanical" machines and even more, they consume generally a lot of energy.

[0008] Further drawback of said machines is the continuous and progressive wear out of the rotating feeding means of the section bar, consisting of rubber wheels, essentially due to the cyclic stop-and-go movement. This causes the irregularity of the punching pitch length varying depending on the wear out of the rubber wheels so obliging a continuos setting of the machine punching pitch.

[0009] The main object of the present invention is to propose a punching machine to carry out slots in section bar stepless moved, for instance, coming out directly from extruders, of metallic and nonmetallic type, in other words for instance, in aluminum or in plastics, at the same time increasing the feeding and punching speed of section bars.

[0010] Further object is to propose a machine automatically setting the punching pitch, keeping it constant, for instance despite of the wear out of the feeding means of the section bars.

[0011] A further object is to propose a machine of simple realization, low cost and high reliability.

[0012] The features of the invention are underlined as follows with particular reference to the attached drawing sheets, in which:

• figure 1 shows a side view of the punching machine;
• figure 2 shows a schematic front view of the machine in figure 1 in which some parts are removed away for better highlighting others;
• figure 3 shows a rear view of the machine in figure 1;
• figure 4 shows a top view of the punching machine in figure 1;
• figure 5 shows a motion law diagram of the oscillation device of the machine in figure 1.

Referring to figures from 1 to 5, numeral 1 indicates a stepless punching machine for extruded section bars, made of aluminum or plastic material, for roller shutters that comprises essentially a supporting frame 9, moving means 10, punching means 20, shifting means 30, indexer means 40, driving means 50.

[0013] This machine 1 is supported by the frame 9 having adjustable feet 8 and to which is connected a table 7 fit to support the section bars moving through the machine along its working axis.

[0014] The moving means 10 includes an electric motor 2 connected by means of belts 4 to a flywheel 3 keyed on a main shaft 11 rotationally supported by the frame 9 by means of a bearing center body 19 interposed therein.

[0015] The punching means 20 include a punch 21 lined up along the section bar moving direction and it is supported by a first carriage 22 fit to slide vertically on a guide 35, fixed to the shifting means 30, by means of the connection to an eccentric member 23, keyed on the main shaft 11 of the moving means 10. Particularly said eccentric member 23 consists of an eccentric 23b and a connecting rod 23a.

[0016] With particular reference to figures 2 and 4, the shifting means 30 include a second carriage 31 sliding on a pair of guides 32 parallel to the moving direction of the section bars. The guide 35 fit for sliding the first carriage 22 is sideways and vertically connected to said second carriage 31.

[0017] The driving means 50 include a pair of belts 33, having the first ends fixed to the opposite side of the second carriage 31 and the remaining ends are fixed to the indexer means 40 by means of a pair of sector gears 51.

[0018] Each sector gear 51 consists of a first circular segment 51a, followed by a second linear segment 51b to which the related end of the belt 33 is fixed, and is connected to the output shaft 47 of the indexer means 40 in order to be radially shiftable in respect to this latter in order to change the linear shifting speed of the shifting means 30 as a consequence of the oscillation speed change of the sector gears 51, as a consequence of the change of the arm length of the force that converts the rotational motion of the output shaft 47 into the linear motion of the second carriage 31.

[0019] The indexer means 40 include an oscillator 41 whose input shaft 42 is driven by the main shaft 11 by means of a belt 44 and whose output shaft 47 transmits an oscillating motion to the driving means 50.

[0020] Figure 5 shows a diagram of the motion law of the oscillator 41 in which:

• the axis of abscissas reports the rotation angles α of the flywheel 3 and of the input shaft of the oscillator (ratio 1:1);
• the axis of ordinates reports liner speed V of the second carriage 31 that practically represents the output motion law of the oscillator;
• the term Vp indicates the speed of the section bar to be punched;
• the term Vr indicates the maximum returning speed of the second carriage 31.

The indexer means 40 receive in input an angular speed (dα/dt) of flywheel 3, consisting in the ratio between the speed Vp of said section bar and the punching pitch. The rotation of the flywheel 3 of 60 degrees, starting from its top dead center corresponding to an angle α equal to zero, causes a liner speed of the second carriage 31 equal to the moving liner speed Vp of the section bar for a period of time corresponding to the rotation 60 (figure 5) of 116 degrees of the flywheel 3: this is the period of time in which the punch 21 and the section bar to be punched are in mutual contact. The real punching phase is shorter and corresponds with the rotation 61 (figure 5) of the flywheel 3 equal to 96 degrees, that is comprised in the 116 degrees rotation above mentioned.

[0021] A further rotation of 60 degrees drives the second carriage 31 to a zero speed during a further rotation 62 (figure 5) equal to 6 degrees until this latter inverts the motion in the following rotation of 118 degrees of the flywheel 3, causing a maximum returning speed Vr of the second carriage 31 to the top dead point, that is the origin of a further punching cycle.

[0022] It is to be noted that the motion inversion phase persists during a rotation of 6 degrees of the flywheel 3.

[0023] The operation of said machine provides first to reach the extrusion speed of the section bars and the punching pitch in order to establish the rotation speed of the flywheel 3 and thus, consequently to change it, for instance, by means of a known and not shown speed variator.

[0024] The operation of the electric motor 2, causes the rotation of the main shaft 11, and therefore the rotation of the eccentric 23b and of the connecting rod 23a that cyclically lowers the first supporting carriage 22 of the punch 21 toward the table 7. The punch movement and then the consequent realization of a series of slots in the section bars occur in phase relationship with the forward motion of the section bar.

[0025] A turn of the flywheel 3 causes a 45 degrees forward and 45 degrees backward rotation of the output shaft of the oscillator according to the motion law above mentioned and carried out by the internal kinematic motion of the oscillator 41.

[0026] The forward rotation angle is the working angle during which the second carriage 31 "follows" the section bar at null relative speed, in order to punch the slots through the section bar by means of the punch 21 not moving relatively with the section bar.

[0027] The adjustment of the sector gears 51 causes a "precise" regulation of the shifting speed of the second carriage 31 acting on the variation of the connection radius length of the timing belt 33 to the output shaft 47 of the oscillator 41.

[0028] When the second carriage 31 moves forward at the speed equal to that of the section bar, at this moment the punch 21 makes the slots on the section bar, then leaves the section bar and the carriage 31 inverts its motion returning to the starting position to carry out a further punching cycle at the maximum speed Vr.

[0029] It is important to highlight that the section bars move forward in the machine 1 during the punching at a speed ranging between 60 and 80 meters per minute: preferable said speed is 70 meters per minute in correspondence of their punching condition.

[0030] The main advantage of the present invention is to provide a punching machine fit to carry out the slots on the stepless moving section bars, for instance directly at the output of the extruders, of the metallic and non metallic kind, in other words, for instance, made of aluminum or plastic material, so increasing at the same time the feeding and punching speeds of the section bars.

[0031] Another advantage is to provide a machine able to set automatically the punching pitch length, keeping it constant, for instance, despite of the wear out of the feeding means of the section bar.

[0032] Further advantage is to provide a machine of simple realization, low cost and high reliability.

Claims

1. Stepless punching machine for extruded section bars characterized in that comprises:

- moving means (10) of punching means (20) including at least a punch (21) moving vertically and fit to punch slots in at least one of said section bars;

- shifting means (30) of said punching means (20) underlying this latter, fit to realize a stop for said at least one section bar in correspondence of a punching condition of the section bar in which said punching means (20) punch every said section bar keeping a preset pitch;

- indexer means (40) to which are kinematically connected in input said moving means (10) for driving the motion and in output are connected driving means (50) fit to move said shifting means (30) according to the moving direction of the section bar at almost null relative speed in correspondence of said punching condition and with contrary direction in correspondence of a not punching condition of said machine (1) in which said section bars move forward through this latter without being punched.

2. Machine according to claim 1 characterized in that said punching means (20) include a set of punches (21) aligned along the motion direction of said section bars and supported by a first carriage (22) vertically moving on a guide (35), fixed to said shifting means (30), by means of the connection to an eccentric member (23), keyed on a main shaft (11) of said moving means (10).

3. Machine according to anyone of the above claims characterized in that said moving means (10) include an electric motor (2) connected by means of belts (4) to a flywheel (3) keyed on the main shaft (11).

4. Machine according to claim 1 characterized in that said shifting means (30) include a second carriage(31) sliding on at least a guide (32) along the moving direction of said section bars.

5. Machine according to claim 1 characterized in that said driving means (50) include a pair of belts (33), whose first ends are connected to the opposite side of said shifting means (30) and the remaining ends are fixed to said indexer means (40) by means of sector gears (51).

6. Machine according to claim 5 characterized in that each of said sector gear (51) consists of a first circular segment (51a) followed by a second linear segment (51b) to which is fixed the related end of said belt (33), with each said sector gear (51) connected to the output shaft (47) of said indexer means (40) in such a way to be radially shifted with respect to this latter in order to vary the linear shifting speed of said shifting means (30) as consequence of the oscillation speed variation of said sector gears (51).

7. Machine according to claim 1 characterized in that said indexer means (40) include an oscillator (41) whose input shaft (42) is driven by said moving means (10) by means of a belt (44) and whose output shaft (47) transmits an oscillating motion to said driving means (50).

8. Machine according to claims 1, 3 and 4 characterized in that said indexer means (40) have in input an angular speed of said flywheel (3), defined by the ratio between the section bar speed (Vp) and the punching pitch, whose 60 degree rotation, beginning from the top dead center of said flywheel (3), drives said second carriage (31) to a linear speed equal to the shifting linear speed (Vp) of said section bar for a time period equal to the rotation (60) of 116 degrees of said flywheel (3), so that a further rotation of 60 degrees drives said second carriage (31) to a null speed that continues for a further rotation (62) of 6 degrees until this latter inverts the movement for the following 118 degrees rotation of said flywheel (3), so causing that said second carriage (31) reaches said top dead center with the maximum spike returning speed (Vr).

9. Machine according to claims 2 and 8 characterized in that said at least one punch (21) and each of said section bar are in contact for a time period as long as the rotation (61) of 96 degrees of said flywheel (3).

10. Machine according to anyone of the above claims characterized in that said section bars move forward in said machine (1) at a speed ranging between 60 and 80 meters per minute, preferably at a speed of 70 meter/minute.

Drawing