DEVICE FOR STRAIGHTENING A STRIP OF SEMI-RIGID MATERIAL AND FEEDING IT INTO A MACHINE

Abstract

A device (1) for straightening a strip of semi-rigid material and feeding the strip into a machine, in particular a metallic sheet into a press or the like. The device comprises a lower frame (3) which carries a set of lower straightening rolls (30), an upper frame (4) which carries a set of upper straightening rolls (40) arranged staggered relative to the lower straightening rolls (30), and a traction mechanism (5) for the strip of material arranged both upstream and downstream from the sets of straightening rolls (30, 40). The device comprises a mechanism for opening and closing (7) the frames (3, 4) in order to carry out a function of gripping/releasing the strip of material which is integrated with a mechanism for adjusting (6) the position of the upper straightening rolls (40) relative to the lower straightening rolls (30), both of the mechanisms are designed to move the upper frame (4) relative to the lower frame (3) in a translation movement perpendicular to the frames and using guiding elements (60) of the mechanism for adjusting (6) the vertical translation.

Description

This application claims priority from French application serial no. 08/05757 filed Oct. 17, 2008.

TECHNICAL FIELD

The present invention concerns a device for straightening a strip of semi-rigid material and feeding it into a machine, in particular a metallic sheet into a press or the like, the said device comprising at least a lower frame carrying a set of lower straightening rolls, an upper frame carrying a set of upper straightening rolls arranged staggered relative to the lower straightening rolls, traction means for the strip of material, positioned upstream and downstream from the said sets of straightening rolls, means for adjusting the position of the upper straightening rolls relative to the lower straightening rolls, and means for opening and closing the said upper and lower frames designed so that, in the closed position, the strip of material is gripped between the lower and upper straightening rolls and, in the open position, the strip of material is released from the constraint of the said straightening rolls.

PRIOR ART

The term “strip of semi-rigid material” is not limited as such to a strip having a certain width, but also includes a filament, a cable, a stranded wire or the like. Similarly the invention applies to any type of semi-rigid material and, in particular, a metallic sheet. One particular application concerns the processing of metallic sheets wound into coils, which are fed into lines for cutting, punching, stamping, folding, etc., during the fabrication of metallic components, for example for the automobile industry. In this field of application presses, or the like, are used which are fed by coil spools, a sheet straightener that unwinds the sheet from its coil and straightens it to remove its curvature, and a device which feeds the sheet section into the press, which alternately grips and releases the sheet as a function of the feeding and cutting cycles of the press.

Depending on the length of the production line, the straightener and the feeding mechanism are distinct modules separated by a sheet reservoir to ensure continuous operation of the press, or they form only one and the same machine, which is commonly called a “straightener-feeder”, with the sheet reservoir located upstream at the level of the spool.

The invention more particularly concerns that type of machine which combines the straightening of the sheet and the feeding of the sheet into the press. This machine has a function commonly called “grip-release” of the sheet, which is synchronized with the feeding and cutting cycles of the press. During the press-feeding phase, the sheet is gripped between the lower and the upper straightening rolls to undergo the straightening operation. During the sheet cutting or stamping phase in the press, the sheet has to be released from constraint, i.e., set free, to enable it to be automatically repositioned in the die of the press.

In current machines, the release function is carried out by opening an upper clamp in a rotary movement about a pivot axis fixed on one side of the shutters in the manner of a jaw, or by raising the upper clamp in a vertical translation movement along specific guide columns. These movements are generated by hydraulic or electro-mechanical actuators, which necessarily need a supply of energy in order to maintain the gripping position. Such mechanisms are bulky, complex to use and very burdensome both in terms of the equipment needed and in their energy demand. Moreover, their inertia is high and, for that reason, their cycle rate is limited. They are not suitable for fitting to machines already in service. In these machines, the straightening rolls can be carried by a single cradle, which makes it impossible to adjust the penetration of each of the straightening rolls individually.

Thus, the current systems are not satisfactory.

EXPLANATION OF THE INVENTION

The purpose of the present invention is to overcome the above disadvantages by proposing a “straightener-feeder” device with a “grip-release” function, which is realized by means that are compact, simple, economical, reliable, which are characterized by very low inertia and can therefore operate at high cycle rates, which need no energy to maintain the gripping position, which can be retrofitted to machines already in service, and which also allow precise and individual adjustment of the penetration of each of the straightening rolls.

To that end, the invention concerns a device of the type indicated in the preamble, characterized in that the said means for opening and closing the said frames are integrated with the said means for adjusting the position of the upper straightening rolls, being designed to move the upper frame relative to the lower frame in a translation movement perpendicular to the said frames, and comprising elements for guiding the said adjustment means in vertical translation.

By virtue of this structure, the mechanical means included are optimized so as to include the grip-release function in a straightening device, using the function of guiding in vertical translation already present in the means for adjusting the position of the straightening rolls.

In a preferred embodiment of the invention, the means for opening and closing the frames comprise a lifting module arranged between the upper frame and the upper straightening rolls, which is coupled to at least one lifting mechanism designed to move the lifting module and, at the same time, the upper frame and the upper straightening rolls in vertical translation between the said closing and opening positions, and vice-versa.

Advantageously, the lifting mechanism comprises at least one cam rotationally driven about a fixed rotation axle by at least one actuator, the said cam cooperating with at least one roller element permanently attached to the said lifting module and comprising a cam profile designed so that the closing position corresponds to a stable condition of the device and the opening position corresponds to a temporary, unstable condition thereof.

In the preferred embodiment of the invention, the cam comprises two first flat sections separated by an angle of about 90° and connected by a first, essentially circular sector, the said cam cooperating with a first, upper roller element permanently fixed to the lifting module so that the first, essentially circular sector defines the unstable, opening position of the device and the first flat sections form rolling ramps on which the upper roller element circulates between the closing and the opening positions.

Advantageously, the said cam has a second flat section diametrically opposite the first, essentially circular sector and connected to the first flat sections by second essentially circular sectors, this cam cooperating with a second, lower roller element permanently fixed to the lifting module and diametrically opposite the upper roller element, such that the said second essentially circular sectors define the stable, closed position of the device.

The gap separating the two, upper and lower roller elements fixed on the said lifting module is advantageously larger than the largest transverse dimension of the cam, and allows a clearance that defines the opening travel of the said device.

The lifting mechanism can comprise at least one control lever articulated at one end to the actuator and at the other end to the fixed rotation axle of the cam. In this case, and advantageously, the lifting mechanism has two actuators mounted in opposition on a fixed frame, each actuator being coupled to the fixed rotation axle of a cam by a control lever, the actuators being mechanically connected so as to function in opposition and combine their forces. These actuators can be chosen from the group comprising a bi-stable pneumatic jack, a servomotor, and this list not being exhaustive.

In the device according to the invention the traction means for the strip of material preferably comprise specific opening and closing means and a central control unit is arranged so as to control simultaneously the means for opening and closing the frames and the means for opening and closing the said traction means.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention and its advantages will be made more clear by the following description of an embodiment, given as a non-limiting example, with reference to the attached drawings in which:

FIGS. 1 to 3 schematically illustrate the working principle of the device according to the invention, respectively in the gripping, release and gripping positions,

FIG. 4 shows a perspective view of a device according to the invention,

FIG. 5 is a view similar to that of FIG. 4 showing the device without the frame,

FIG. 6 is a front view of the device in FIG. 4,

FIG. 7 shows a longitudinally sectioned view of FIG. 6 at the level of the actuators, and

FIG. 8 is a view of the device in FIG. 4, seen from above.

DETAILED DESCRIPTION OF THE DRAWINGS

Illustrations of the invention and the best way to produce it:

According to the invention, the device 1 for straightening a strip 2 of semi-rigid material and feeding it into a machine, in particular a metallic sheet into a press or the like, in a known way, and referring to the figures, comprises a lower frame 3 carrying a set of lower straightening rolls 30, an upper frame 4 carrying a set of upper straightening rolls 40 arranged staggered, relative to the lower straightening rolls 30, traction means 5 for the strip 2 of material arranged upstream and downstream from the said sets of straightening rolls 30, 40 and means 6 for controlling the vertical position of the upper straightening rolls 40 relative to the lower straightening rolls 30, which means comprise elements 60 for guiding each upper straightening roll 40 in vertical translation.

In the example illustrated, the lower frame 3 is fixed and constitutes the supporting structure of the device 1 as a whole. It carries a set of four mutually parallel lower straightening rolls 30 aligned in the same horizontal plane, separated by regular inter-axial distances and rotationally driven by an assembly of driving gears 31 which engage with receiving gears 32 fitted at one end of each lower straightening roll 30 (see FIGS. 5 and 7).

In the example illustrated, the upper frame 4 is mobile and carries a set of three mutually parallel upper straightening rolls 40 separated by regular inter-axial distances equal to those of the lower straightening rolls 30 but offset relative to the latter. The penetration depth of each upper straightening roll 40, between two adjacent lower straightening rolls 30, can be adjusted in order to adapt the degree of straightening to a given strip of material. To enable this, each upper straightening roll 40 is carried at its two ends by two guiding elements 60 which comprise bearings and slide in two grooves 61 provided in the lower frame 3. The position adjustment means 6 comprise, for each upper straightening roll 40, two threaded rods 62 which extend vertically across the said upper frame 4 and which have a lower end 63 engaged with each guiding element 60 and an upper end 64 which is rectangular so that it can be moved by a suitable tool 65, which can be manual or automatic. Screwing in and out of the threaded rods 62 lowers or raises the corresponding upper straightening roll 40. The threaded rods 62 are mechanically coupled by a transmission, with a sprocket 66 and chain 67, to synchronize the movement of the two ends of the same upper straightening roll 40.

The traction means 5 for the strip 2 of material, arranged upstream and downstream from the sets of straightening rolls 30, 40, each comprise, in a known way, a fixed lower traction roll 50 carried by the lower frame 3, and a mobile upper traction roll 51 carried by a bearing 52 which slides in a groove 53 of the lower frame 3. An actuator 54, such as a motor, is coupled to at least one of the lower traction rolls 50, engaging with the drive gears 32 in order to rotationally drive the lower straightening rolls 30. They also comprise means 55 for opening and closing the upper traction roll 51 relative to the traction roll 50, which are arranged so as to grip the strip of material when in the closed position to move it forward, and to release the strip of material when in the open position. These opening and closing means 55 comprise actuators arranged in line with each end of the upper traction rolls 51 and controlled by a central control unit (not shown). In the example illustrated, the actuators preferably consist of pneumatic jacks 55 whose rod 56 engages with the sliding bearing 52, but they can be replaced by servomotors or any other known actuator, whether pneumatic, hydraulic or electric.

According to the invention, the device 1 for straightening a strip 2 of material and feeding it into a machine comprises means 7 for opening and closing the upper 4 and lower 3 frames arranged so that, in the closed position, the strip 2 of material is gripped between the lower 30 and upper 40 straightening rolls while, in the open position, the strip 2 of material is released from the constraint of the straightening rolls 30, 40. These opening and closing means 7 of the frames 3, 4 are controlled by the central control unit (not shown) simultaneously with the traction means 5, so that the strip 2 of material is released from any constraint.

The opening and closing means 7 differ from the prior art in that they are integrated with the means 6 for adjusting the position of the upper straightening rolls 40 and are designed to move the mobile upper frame 4 and the upper straightening rolls 40, relative to the fixed lower frame 3, and the lower straightening rolls 30 in a translation movement perpendicular to the said frames 3 and 4. To do this, they use the guiding elements 60 for the vertical translation of the adjustment means 6. For that purpose they comprise a lifting module 70 arranged between the upper frame 4 and the upper straightening rolls 40, coupled to a lifting mechanism 71, 72 designed to move the lifting module 70, along with the upper frame 4 and the upper set of straightening rolls 40, in vertical translation between the closed position, corresponding to the function of gripping the strip 2 of material, and the open position, corresponding to the function of releasing the strip 2 of material.

Referring also to FIGS. 1 to 3, which illustrate schematically the working principle of these opening and closing means 7, the lifting mechanism comprises at least one cam 71 and preferably two parallel cams 71 spaced a distance apart from one another and arranged in the end zone of the lifting module 70 in order to distribute the forces. Each cam 71 is rotationally driven about a fixed rotation axle A by at least one actuator 72, and the fixed rotation axle A and the actuator 72 is carried by a fixed frame 73 which is an extension of the lower frame 3. In the illustrated example, the actuator 72 is a bi-stable pneumatic jack. Any other actuator 72 would be suitable, for example a servomotor. In the example shown, the lifting mechanism comprises two jacks 72 mounted on the fixed frame 73 in opposition and connected mechanically so as to function in opposition and combine their forces. More particularly, each jack 72 is mounted on the fixed frame 73 by an articulation axis F and the rods 76 of the two jacks 72 are connected to one another by an assembly of articulated stirrups 77. Each cam 71 is rotationally driven by a control lever 78 coupled at one end to the corresponding actuator 72 by an articulation G provided on one of the stirrups 77, and at the other end to the fixed rotation axle A of the cam 71.

Each cam 72 is arranged between an upper roller element 74 and a lower roller element 75, consisting respectively of an upper roller and a lower roller diametrically opposed and able to rotate about rotation axles fixed on the lifting module 70 and parallel to the fixed rotation axle A of the cam 71. The gap E, separating the roller elements 74, 75, is wider than the largest transverse dimension D of the cam 71 and allows a clearance, for example of a few millimeters, which defines the opening travel C of the device 1 (see FIG. 2).

Each cam 71 has a cam profile designed so that the closed position is a stable condition of the device 1 and the open position is a temporary, unstable condition thereof. More particularly, each cam 71 has two flat sections 711 separated by an angle of about 90° and connected by a first essentially circular sector 712, which cooperate with the upper roller element 74 fixed on the lifting module 70 in such a manner that the first essentially circular sector 712 defines the opening position of the device 1 (see FIG. 2) and the first flat sections 711 form rolling ramps on which the said upper roller element 74 circulates between the closing and opening positions. In the closing position (see FIGS. 1 and 3), the first flat sections 711, with the upper roller element 74, delimit a clearance corresponding to the opening travel C of the device 1.

Each cam 71 also has a second flat section 713, which is diametrically opposite the first essentially circular sector 712 and is connected to the first flat sections 711 by second essentially circular sectors 714 which cooperate with the lower roller element 75 fixed on the lifting module 70 to define the stable closing position of the device 1. In the opening position (see FIG. 2), the second flat section 713, together with the lower roller element 75, delimit a clearance corresponding to the opening travel C of the device 1. The lifting module 70 is guided in vertical translation both by the guiding elements 60 of the upper straightening rolls 40 and by the lateral parts of the fixed frame 73 (which are not shown in the figures).

The operation of the opening and closing means 7 of the device 1 will now be described with reference to FIGS. 1 to 3 which show, in simplified form and without the traction means 5, the device 1 for straightening and feeding a strip 2 of material.

In FIG. 1, the device 1 is in a stable, closed position with the strip 2 of material gripped between the lower 30 and upper 40 straightening rolls, undergoing a straightening process during its forward feed. The jack 72 on the right is in a stable, retracted position and the jack 72 on the left in a stable extended position, the control levers 78 are orientated to the right and the cams 71 are in tangential contact on their second sector 714 against the lower roller elements 75, keeping the lifting module 70 in its low position and, at the same time, keeping the upper frame 4 and the upper straightening rolls 40 in a stable, closed position with no consumption of energy. In this position, the clearance corresponding to the opening travel C is located between the first corresponding flat section 711 of the cams 71 and the upper roller elements 74.

FIG. 2 shows the device 1 in an unstable and temporary position, in which the strip 2 of material is released from the constraint of the straightening rolls 30 and 40 and is no longer moving forward, being therefore able to self-center itself relative to the dies of the press. The jacks 72 are working and under pressure, the jack on the right being in a partially extended position and the jack on the left in a partially retracted position, while the control levers 78 have turned through about a quarter of a revolution in the direction of arrow R1, moving the cams 71 with them. During such rotation, the second sector 714 of the cams 71 moves away from the lower roller elements 75 and the first flat section 711 of the cams 71 contacts the upper roller elements 74, causing the lifting module 70 to move vertically up to its high position, along with the upper frame 4 and the upper straightening rolls 40 until, corresponding to the maximum opening travel C, the first sector 712 of the cams 71 reaches its position defining the unstable, temporary open position with energy consumption. In this position, the clearance corresponding to the opening travel C is transferred to between the second corresponding flat section 713 of the cams 71 and the lower roller elements 75.

FIG. 3 shows the device 1 after returning to a stable, closed position with the strip 2 of material again gripped between the lower 30 and upper 40 straightening rolls, so as to continue the straightening process during its forward-feed movement. The jacks 72 have continued working, in the same direction, and the jack on the right is now in a stable, extended position while the jack on the left is in a stable, retracted position, the control levers 78 having continued their rotation through a quarter-turn in the direction of arrow R2, moving the cams 71 with them. During this rotation the first sector 712 of the cams 71 moves away from the upper roller elements 74, which roll over the other first flat section 711 of the cams 71, causing a vertical downward movement of the lifting module 70 to its low position along with the upper frame 4 and the upper straightening rolls 40, until the section sector 714 of the cams 71 again encounters the lower roller elements 75, which corresponds to the stable, closed position in which no energy consumption is needed.

To carry out a new grip/release/grip cycle, the jacks 72 are actuated in the reverse direction. The angular displacement of the cams 71 is limited to an angle of about 90°, which is sufficient to produce these cycles. In fact, it is easy to see that this mechanism has a very rapid response time which enables it to reach high cycling rates.

Possible industrial applications:

The components, sub-assemblies and assemblies constituting the device 1, according to the invention, are made by reproducible industrial processes. The device 1 is not limited to straightening a sheet and feeding the straightened sheet into a press, but can be used for any other application that requires the functions of straightening and feeding into any type of machine.

From the above description it emerges clearly that the invention makes it possible to fulfill specific purposes. In particular, it enables the function of “gripping/releasing” associated with a straightening machine, with the help of an optimized mechanism thanks to which the gripping function is stable and does not require energy input.

The present invention is not limited to the example embodiment described, but extends to any modification and variant that would be obvious to those with knowledge of the field while remaining within the scope of protection defined by the attached claims.

Claims

1-10. (canceled)

11. A device (1) for straightening a strip (2) of semi-rigid material and feeding the strip (2) into a machine, in particular a metallic sheet into a press or the like, the device comprising: at least one lower frame (3) which carries a set of lower straightening rolls (30),an upper frame (4) which carries a set of upper straightening rolls (40) arranged staggered relative to the lower straightening rolls (30),traction means (5) for the strip of material arranged both upstream and downstream from the sets of straightening rolls (30, 40),means for adjusting (6) the vertical position of the upper straightening rolls (40) relative to the lower straightening rolls (30), the means for adjusting (6) comprising guiding elements (60) for the vertical translation of each upper straightening rolls (40), and means for opening and closing (7) the upper (4) and lower (3) frames designed such that, in a closed position, the strip (2) of material is gripped between the lower straightening rolls (30) and the upper straightening rolls (40) and, in an open position, the strip (2) of material is released from the constraint of the straightening rolls (30, 40),wherein the means for opening and closing (7) the frames (3, 4) are integrated with the means for adjusting (6) the position of the upper straightening rolls (40) and are designed to move the upper frame (4), relative to the lower frame (3), in a translation movement perpendicular to the frames (3, 4), and comprise guiding elements (60) of the adjustment means (6) in vertical translation.

12. The device according to claim 11, wherein the means for opening and closing (7) the frames comprise a lifting module (70) arranged between the upper frame (4) and the upper straightening rolls (40), and coupled to at least one lifting mechanism (71, 72) designed to move the lifting module (70) and, at the same time, the upper frame (4) and the upper straightening rolls (40) in vertical translation between the close and open positions, and vice-versa.

13. The device according to claim 12, wherein the lifting mechanism comprises at least one cam (71) rotationally driven about a fixed rotation axle (A) by at least one actuator (72), the cam (71) cooperating with at least one roller element (74, 75) fixed on the lifting module (70) and having a cam profile designed so that the close position corresponds to a stable condition of the device (1) and the open position corresponds to a temporary, unstable condition of the device (1).

14. The device according to claim 13, wherein the cam (71) has two first flat sections (711) separated by an angle of about 90° and connected by a first essentially circular sector (712), the cam (71) cooperating with a first, upper roller element (74) fixed on the lifting module (70) in such a manner that the first essentially circular sector (712) defines the unstable open position of the device (1) and the first flat sections (711) form rolling ramps on which the upper roller element (74) rotates between the close and open positions.

15. The device according to claim 14, wherein the cam (71) has a second flat section (712), diametrically opposite the first essentially circular sector (712) and connected to the first flat sections (711) by second essentially circular sectors (714), the cam (71) cooperating with a second, lower roller element (75) which is fixed on the lifting module (70) and diametrically opposite the upper roller element (74) in such a manner that the essentially circular second sectors (714) define the stable, close position of the device (1) and the second flat section (713) forms a clearance zone which defines the opening travel C of the device (1).

16. The device according to claim 15, wherein a gap (E), separating the two, upper (74) and lower (75) roller elements fixed on the lifting module (70), is wider than the largest transverse dimension (D) of the cam (71), and allows a clearance which defines the opening travel (C) of the device (1).

17. The device according to claim 13, wherein the lifting mechanism comprises at least one central control lever (78) articulated at one end to the actuator (72) and at the other end to the fixed rotation axle (A) of the cam (71).

18. The device according to claim 17, wherein the lifting mechanism has two actuators (72) mounted in opposition to one another on a fixed frame (73), each actuator (72) is coupled to the fixed rotation axle (A) of one cam (71) by a control lever (78), and the actuators (72) are mechanically connected so as to operate in opposition and combine their forces.

19. The device according to claim 13, wherein the actuator (72) is selected from the group comprising a bistable pneumatic jack and a servomotor.

20. The device according to claim 11, wherein the traction means (5) of the strip (2) of material comprise separate opening and closing means and the device comprises a central control unit for simultaneously controlling the means for opening and closing (7) the frames (3, 4) and the opening and closing means of the material strip traction means (5).