EP0449681B1 - Device for feeding automatically blanks to a press or any other machine - Google Patents

Description

The present invention essentially relates to an apparatus for automatically feeding sheet blanks to any machine such as, for example, a press which may be a so-called "double-effect" press, that is to say a press which is used on the one hand to plate the sheet and on the other hand to deform it.

Devices have already been proposed for supplying sheet blanks of a press, which devices can be fixed to the press and generally comprise means capable of gripping a sheet placed on a holding support and then introduce this sheet into the press. Apparatuses of this type and as described in the preamble of claim 1, are already known from document FR-A-1,326,785.

However, these devices do not allow the press to be served with sufficient reliability and do not allow the press to work at a high rate.

Also, the present invention aims to remedy these drawbacks by proposing an automatic feeding device or sheet metal feeder for a press, which allows the press to work without stopping the punch, that is to say say to work "on the fly", and this at high rates of the order of twenty to twenty-five strokes per minute, so that the performance of the press is significantly improved.

To this end, the subject of the invention is an apparatus for automatically feeding sheet blanks to a press or any other machine, of the type intended to be fixed to the press and comprising means capable of gripping a sheet placed on a waiting support and then to introduce this sheet into the press, said apparatus further comprising at least one carriage provided at least one sheet unstacking system which feeds said holding support in a coordinated and synchronous manner with the introduction of the sheets into the press by said carriage which is mounted movable in an alternating movement on a frame, characterized in that the carriage is provided with means for gripping a sheet, and the waiting support is fixed to the frame in a movable and retractable manner, so that in the high position of the waiting support, said gripping means can grasp on the fly a sheet resting on said support in order to introduce it into the press and so that in the low position of the waiting support, the carriage can move back without interfering with a sheet previously deposited on said support by the unstacking system.

It will be specified here that the unstacking system is mounted on the carriage at a place such that in the withdrawn position of the carriage, it is located in line with a stack of sheets while means for gripping a sheet integral with the carriage located at the stand, while in the advanced position of the carriage or the introduction of a sheet into the press, the unstacking system is located to the right of the stand.

According to yet another additional characteristic of the invention, the waiting support is integral with a deformable frame mounted on a support fixed to the aforementioned frame.

The aforementioned deformable frame substantially forms an articulated parallelogram and deformable by means of a jack mounted on the aforementioned support.

According to an additional characteristic of the apparatus of this invention, the unstacking system comprises suction cups or other similar means integral with a support mounted vertically movable on a chassis and actuable by a jack fixed on said chassis itself optionally fixed adjustable on the trolley.

According to an additional characteristic of the invention, the carriage is driven in an alternative movement of translation on a guide rail integral with the frame, by means of an indexer-oscillator mounted on the frame, comprising an arm hingedly connected to the carriage, and whose motion law is adapted to the press cycle.

It will also be specified here that according to the invention, the means for gripping a sheet on the waiting support are constituted by clamps arranged at one end of the carriage and controlled by a rod or the like actuated by means forming cam under the effect of the movement of the carriage relative to the frame.

The aforementioned means forming a cam are constituted, according to a preferred embodiment, by a substantially L-shaped part pivotally mounted on the carriage, one of the branches of which carries a finger, roller or the like engaged in a groove or cam path practiced in an element fixed on the frame, and the other branch of which is articulated on one of the ends of the aforementioned rod.

According to an additional characteristic of the device according to the invention, the other end of the rod is hingedly connected to two supports which respectively carry gripper arms opposite, and which are mounted for rotation on a intermediate piece mounted adjustable on the carriage.

It will be observed that the above-mentioned clamp arms are advantageously mounted adjustable on the two supports controlled by the rod so as to allow the spacing of the clamp arms to be adjusted as a function of the dimensions of the sheets to be gripped.

According to yet another additional characteristic of the invention, the length of the aforementioned rod is adjustable by means of a connector constituted by a sheath articulated on the L-shaped part and in which said rod is telescopically mounted, by a socket mounted on said sheath , and by a nut co-operating with this socket and the rod and having a tapped orifice of diameter greater than that of the rod and capable of being released from the rod after unlocking and displacement of the sleeve relative to said sleeve, said rod being threaded at less at the connection.

The apparatus of this invention is further characterized by the fact that the aforesaid frame is mounted vertically sliding and adjustable on a support itself fixed on the press.

It will be observed that the frame is movable relative to the aforementioned support by means of a geared motor unit driving a ball screw and comprising a disc brake.

The frame can be held, in a determined position, against the aforementioned support by means of elastic arms forming levers articulated on the support and each controlled by cams, eccentric or the like actuated by jacks mounted articulated on the support.

This will give a reliable and precise positioning of the loading device relative to the press on which it is fixed, so that the introduction of the sheets gripped by the clamps of the carriage in the press will be carried out with excellent reliability.

However, other advantages and additional characteristics of the invention will appear more clearly in the detailed description which follows and refers to the appended drawings, given solely by way of example and in which.

Figure 1 is a perspective view of an automatic device for loading sheet blanks according to one embodiment of the invention, and fixed on a press shown very partially.

Figure 2 is an elevational and side view of the device in the position of introduction of a sheet in the press, that is to say in the advanced position of the carriage.

Figure 3 is a view similar to Figure 2, but showing the device in the retracted position of the carriage for gripping a sheet on a stack of sheets.

FIG. 4 is a plan view and from above of the apparatus fixed on the press, the carriage being in the retracted position, as in FIG. 3.

Figure 5 is a perspective view of the carriage.

Figure 6 is a schematic view of the clamps carried by one end of the carriage and shown in the open position and in the closed position.

Figure 7 is a schematic and plan view of a groove formed in a part fixed to the frame of the device and allowing, during the reciprocating movement of the carriage, the actuation of a rod controlling the clamps.

Figure 8 is a sectional view of a connector for adjusting the length of the rod to adjust the position of the clamps relative to the carriage.

Figure 9 is a perspective view of the unstacking system.

FIG. 10 is a perspective view of the waiting support fixed to the frame of the device.

Referring in particular to FIGS. 1 to 4, and according to an exemplary embodiment, an apparatus for automatically feeding or loading sheet blanks according to this invention essentially comprises a frame 1 mounted vertically movable by a plate-shaped part 2 on a support 3 which is itself fixed by bolting for example, as seen in 4, on the front face 5 of a PR press.

We see at E in FIG. 4 elements constituting the base of the PR press, and we see on this same figure the successive positions of a sheet blank TO to be introduced into the PR press through an opening O provided on the front face 5 of said press, using the loading apparatus according to this invention. The frame 1, as seen in FIGS. 1 to 4, supports a carriage 6 which in turn supports a system 7 for unstacking sheets and means 8 for gripping a sheet arranged at one end of the carriage 6. On the frame 1 of the device is fixed movably in the manner of a swing, a waiting support 9 which can be retracted when the carriage 6 moves back, as will be explained in detail below. About the operation.

As it clearly appears in FIGS. 1 to 3, the carriage 6 can be driven by a substantially horizontal reciprocating translational movement on a guide rail 10 secured to the frame 1, and this thanks to an electromechanical indexer-oscillator of a type known per se which is generally identified at 11 and which is integral with the frame 1. More specifically, this indexer-oscillator 11 is provided with a swinging arm 12 hingedly connected at one end by means of a roller or the like 13 to the carriage 2 which can thus perform a back-and-forth movement on the rail 10. It will be observed that the indexer-oscillator 11 has a law of specific movement adapted to the operating cycle of the press, thanks to a cam (not shown) having a particular profile.

The unstacking system 7 integral with the carriage 6, comprises, as can be seen more clearly in FIG. 9, a plurality of suction cups 14 connected to a source of vacuum and pressure (not shown) by conduits in the form of coils 15, and carried by a support 16 having somewhat the shape of a frame. This support 16 is mounted vertically movable on a chassis 17 which is itself fixed on the carriage 6. A jack 18a is fixed on the chassis 17 and allows the vertical actuation of the support 16 carrying the suction cups 14 relative to said chassis integral with the carriage 6. More precisely, and as can be seen in FIGS. 5 and 9, the chassis 17 comprises cross-members 18 with a T cross section which can be mounted in two parallel rails 19 integral with the carriage 6 (FIG. 5) so as to allow the adjustment, in the horizontal plane, of the unstacking system 7 before its final attachment to the carriage 6.

As it clearly appears in FIG. 5, the means 8 for gripping a sheet on the waiting support 9 which will be described later, consist of clamps P arranged at one end of the carriage 6 and controlled by a rod T actuable by means forming a cam 20 under the effect of the movement of the carriage 6 relative to the frame 1.

More specifically, the clamps P are constituted by pairs of arms 21 opposite and respectively integral with two supports 22 which are each mounted in rotation, for example by means of knee pads (not visible in the figures), on a intermediate piece 23 mounted adjustable at the end of the carriage 6.

As can be clearly seen in the diagram in FIG. 6, one of the ends of the rod T is connected in an articulated manner at 24 on the supports 22 so that a push of the rod T opens the clamps P, while qu 'a pull on this rod causes the closure of said clamps.

Returning to FIG. 5, it can be seen that certain clamp arms 21 have recesses 25 making these arms somewhat elastic to facilitate tightening on the sheet metal TO be grasped on the waiting support 9.

We see in Figure 5 that the cam means 20 are constituted by a part 25 substantially L-shaped pivotally mounted at 26 on the carriage 6. One 27 of the branches of L carries a finger or roller 28 to one from its ends, which finger or roller is engaged in a groove forming a cam track 29 which is best seen in FIG. 7 and which is produced in a part 30 fixed to the frame 1 by legs or the like 31 clearly visible on Figure 5. The other branch 32 of the L-shaped part 25 is articulated, as seen in 33, at the end of the rod T opposite to that capable of actuating in rotation the supports 22 of the clamps P , as described above.

In this regard, it will be observed that the arms 21 of the clamps P are mounted laterally adjustable on their respective supports 22 so as to allow the spacing of said arms to be adjusted. As it clearly appears in FIG. 5, a connection has been provided for this purpose by dovetail and mortise tenon between the arms 21 and the supports 22, as seen in 34.

As is clearly visible in Figures 5 and 8, the length of the rod T is adjustable by means of a connector 35, and this so as to adjust the position of the clamps P relative to the carriage 6, depending on the dimension sheets to grab.

This connector 35 is essentially constituted by a sheath 39 in which the rod T is telescopically mounted, said sheath constituting the end of the rod which is articulated at 33 on the L-shaped part 25 pivotally mounted at 26 on the carriage 6. A sleeve 36 is slidably mounted on the sleeve 39 and, in this sleeve, is slidably fitted a nut 37 having a threaded orifice 38 of diameter greater than that of the threaded rod T, as can be seen in FIG. 8. Otherwise said, the rod T is engaged and held only on a portion of the thread of the threaded orifice 38 of the nut 37. On the sleeve 36 are articulated levers 60 allowing the locking of said sleeve on the sleeve 39 A ring 61 slidably mounted on the sheath 39 and urged by at least one spring 62 allows the blocking or unblocking of the levers 60, as can be seen clearly in FIG. 8. We also see at 63 a sleeve tr showered by the rod T and held in place by a support 64 integral with the carriage 6. A lug has been shown at 65 which can be struggled in a groove 66 formed on the periphery of the sheath 39, and we see in 67 a flange belonging to the sheath 39 and forming an end of travel stop for the sleeve 36. An annular part 68 is provided on the bushing 36 in particular for producing a stop for the springs 62 urging the ring 61.

Thus, to carry out the adjustment of the rod T, the levers 60 are unlocked, which allows the recoil to the right of FIG. 8 of the sleeve 36 on the sleeve 39 and this up to the stop 67. Obviously, the unlocking levers 60 is made after actuating the ring 61, against the force of the springs 62. It follows that the nut 37 is released from the sleeve 36 and can therefore be detached from the threaded rod T with which he was originally engaged in. The rod T is then moved to the desired length, which allows the movement of the set of clamps P relative to the carriage 6 (FIG. 5), it being understood that the intermediate piece 23 on which the clamp supports 22 will pivot will be moved accordingly with respect to the carriage 6. Once the adjustment has been made, the nut 37 is replaced on the rod T, and the sleeve 36 is brought back onto this nut by sliding thereon, then the said sleeve is locked on the sheath with the levers 60, as seen in FIG. 8.

The waiting support 9 secured to the frame 1 and better visible in Figure 10 is secured to a deformable frame 40 itself connected to a support 41 fixed by its part 42 on the frame 1 of the device. More specifically, the deformable frame 40 is formed of a plurality of links constituting substantially an articulated parallelogram and deformable by means of a jack 43 mounted articulated on the support 41.

Thus, the standby support 9 can move in the manner of a swing with respect to the frame 1, as will be explained later in connection with operation. It will also be observed here that the waiting support 9 comprises a plurality of horizontal pads 44 on which a sheet metal TO can rest. At 45 have been shown magnets provided on some of these pads 44 for holding the sheet, it being understood that some of said pads can be mounted in an adjustable manner on the holding support 9. Also, it is possible to provide at the level of the 'one of the pads 44 a detector 46 of the presence of a sheet. Finally, we see at 40a an arm secured to the deformable frame 40 and capable of cooperating with one or the other of two limit switch contacts 40b to limit the movement of the frame 40.

Returning to FIGS. 1 to 4, it can be seen that the frame 1 of the device is movable relative to the support 3 fixed on the press PR thanks to a geared motor group 47 which drives a ball screw 48 and which is provided with a brake disc 49. It is therefore understood that the frame 1 is mounted adjustable on the support 3 fixed to the press PR, and in this regard, it will be noted that the part or plate 2 belonging to this frame is mounted vertically sliding in rails 2a ( Figure 1) belonging to the support 3. Furthermore, the frame 1 supporting the indexer-oscillator 11, the carriage 6 and its associated elements, as well as the standby support 9 is maintained, after adjustment in the vertical direction relative to the support 3, in a position determined against said support. To this end, as can be seen in FIGS. 1 and 4, elastic arms 50 forming levers are articulated at 51 on the support 3 and are each controlled by cams or eccentrics 52 secured to a shaft 53 (FIG. 1) actuated by jacks 54 (FIG. 4) mounted articulated on the support 3. More precisely, and as can be seen in FIG. 4, the body of the jacks 53 is articulated on the support 3 and the rods of these jacks control the rotation of the cams or eccentrics 52 which cooperate with one of the ends of the arms 50, the other end of which can bear on the part or plate 2 of the frame 1, thereby securing the frame with the support 3 itself fixed on the front face 5 of the PR press.

We see in M in Figures 1 to 4 the drive motor of the indexer-oscillator 11 which, as we said above, controls the back and forth movement of the carriage 2 and its associated elements .

However, for a better understanding of the invention, the operation of the sheet blank loading device in the PR press, which has just been described, will be described below, with particular reference to FIGS. 2 and 3.

It will be assumed that at the start of the cycle, the various elements of the apparatus are in the position of FIG. 3.

In this position, a sheet blank TO will already be on the waiting support 9 which is in the high position. Another TO sheet side is attached to the suction cups 14 of the unstacking system 7 which is in the raised position after having been fetched the first sheet metal TO from a stack G of sheets.

The cycle start is given by an electrical signal from the PR press, and the following sequence of operations occurs.

The carriage 6, actuated by the indexer-oscillator 11 advances, as can be seen in FIG. 2, while the standby support 9 is always in the high position, contrary to what is shown in this figure, where said stand has been shown in the low position for clarity.

The clamps P close thanks to the means forming a cam 20 actuating the rod T and the sheet blank resting on the waiting support 9 in the high position is gripped on the fly.

The carriage 6 ends its forward stroke until the introduction of the sheet metal blank gripped by the clamps P into the press tool.

At this stage, there is an opening of the clamps P always thanks to the cam means 20 which is at the end of the groove 29, that is to say in the extreme left part of FIG. 7. The sheet metal blank will be thus released in the press.

Simultaneously, the unstacking system 7 which is located in line with the waiting support 9 still in the high position, will deposit a sheet blank on said waiting support.

The carriage 6 will move back and, simultaneously, the standby support 9 will move downward, as shown in FIG. 2 to allow passage to the carriage 6 which moves back and which will therefore not be able to interfere with the sheet metal blank previously deposited by the unstacking system 7 on said stand.

The carriage 6 ends its recoil stroke to return to the position shown in FIG. 3.

The unstacking system 7 will then look for a new sheet blank on the stack G, while the waiting support 9 returns to the high position visible in FIG. 3, so that the above sequence of operations begins again.

It will be observed here that the speed of the carriage back and forth is adjusted with that of the press by action on a frequency converter (not shown) which controls the motor M of the indexer-oscillator 11.

It is important to emphasize here that the unstacking system 7 associated with the carriage 6 feeds the waiting support 9 in a perfectly coordinated and synchronous manner with the introduction of the sheets TO in the press PR by said carriage.

It is thus possible, thanks to the structure and operation of the automatic sheet loading apparatus according to this invention, to obtain press rates of the order of twenty to twenty-five strokes per minute, which is much higher than with the systems of the prior art.

Claims (13)

1. Apparatus for automatically feeding a press with metal sheet blanks, of the type intended to be fastened to the press and comprising means (8) apt to grip a metal sheet (TO) placed on a stand-by support (9) and to then insert this metal sheet into the press (PR), the said apparatus further comprising at least one carriage (6) provided with at least one system (7) for unstacking metal sheets which is feeding the said stand-by support (9) in a co-ordinated manner synchronously with the insertion of the metal sheets (TO) into the press (PR) by the said carriage which is mounted to be displaceable according to a reciprocating motion on a frame (1), characterized in that the carriage (6) is provided with means (8) for gripping one metal sheet and the stand-by support (9) is fastened to the frame (1) in a movable and retractable fashion so that in the upper position of the stand-by support (9), the said gripping means (8) may grip on the fly a metal sheet (TO) resting upon the said support in order to insert it into the press (PR) and in order that in the lower position of the stand-by support (9), the carriage (6) may move backwards without interfering with a metal sheet previously laid down upon the said support by the unstacking system (7).
2. Apparatus according to claim 1, characterized in that the stand-by support (9) is made fast to a deformable frame (40) mounted on a holder (41) fastened to the frame (1) of the apparatus.
3. Apparatus according to claim 2, characterized in that the aforesaid deformable frame (40) substantially forms a parallel motion deformable by means of a jack (43) mounted on the aforesaid holder (41).
4. Apparatus according to claim 1, characterized in that the aforesaid unstacking system (7) comprises suction cups or other like means (14) made fast to a support (16) vertically mounted movably onto a frame (17) and operable by a jack (18a) fastened onto the said frame itself fastened in a possibly adjustable manner onto the carriage (6).
5. Apparatus according to one of the foregoing claims, characterized in that the aforesaid carriage (6) is driven according to a reciprocating translatory motion on a guide rail (10) made fast to the frame (1) by means of an indexer-oscillator (11) mounted on the frame (1), comprising an arm (12) connected in a pivoted manner to the said carriage and the law of movement of which is adapted to the cycle of the press.
6. Apparatus according to one of the foregoing claims, characterized in that the means (8) for gripping one metal sheet on the stand-by support (9) are constituted by tongs (P) arranged at one (23) of the ends of the carriage (6) and controlled by the rod or the like (T) actuatable by cam means (20) under the effect of the displacement of the carriage with respect to the frame (1).
7. Apparatus according to claim 6, characterized in that the cam means (20) are constituted by a substantially L-shaped part (25) pivotally mounted (26) on the carriage (6), one (27) of the legs of which carries a finger, roller or the like (28) engaging a camming groove or track (29) formed in a member (30) fastened to the frame (1) and the other leg (32) of which is pivotally connected (33) to one of the ends of the aforesaid rod (T).
8. Apparatus according to claim 6 or 7, characterized in that the other end of the rod (T) is connected in a pivoted manner (24) to two supports (22) which carry confronting tong arms (21), respectively, and which are mounted for rotation on an intermediate part (23) adjustably mounted on the carriage (6).
9. Apparatus according to one of claims 6 to 8, characterized in that the aforesaid tong arms (21) are adjustably mounted on both supports (22) controlled by the rod (T) so as to allow the adjustement of their spacing.
10. Apparatus according to one of claims 1 to 9, characterized in that the length of the aforesaid rod (T) is adjustable by means of a coupling (35) constituted by a quill (39) pivotally connected (33) to the L-shaped part (25) and within which the said rod is telescopically mounted by a bushing (36) mounted onto the said quill and by a nut (37) co-operating with this bushing and the rod and having a tapped opening (38) with a greater diameter than that of the rod (T) and capable of being disengaged from the rod after unlocking and displacement of the bushing (36) with respect to the said quill (39), the said rod being threaded at least at the level of the coupling (35).
11. Apparatus according to one of the foregoing claims, characterized in that the aforesaid frame (1) is slidably and adjustably vertically mounted onto a support (3) itself fastened to the press (PR).
12. Apparatus according to claim 11, characterized in that the aforesaid frame (1) is displaceable with respect to the support (3) by means of a motor-speed reducer set (47) driving a ball screw (48) and comprising a disc brake (49).
13. Apparatus according to claim 11 or 12, characterized in that the frame (1) is held in a determined portion against the aforesaid support (3) by means of elastic arms (50) forming levers (51) pivotally connected to the support (3) and each one operated by cams, eccentrics or the like (52) actuated by jacks (53) pivotally mounted onto the said support.

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