EP0633077A1 - Device for intermittent feed of workpieces - Google Patents

Abstract

A device (1) for the intermittent feed of workpieces, for example in a press (2) or similar production machine or in other processing operations to be carried out in steps, has two feed bars (3) which can be moved backwards and forwards in the feed direction, have gripping parts (3a) or gripping regions for gripping the workpieces (100), to grip the workpieces can be moved towards one another and, to perform an advance in this gripping position, can be moved jointly in the feed direction and then release the workpieces by moving apart and can be displaced back into the starting position by means of a return movement. Engaging on each feed bar (3) are the pivotable ends (5) or end regions of at least two levers (4), which can be pivoted in the plane of motion of the feed bar (3) or a plane parallel thereto, the levers (4) of one feed bar (3) being pivotable in the opposite direction to those of the other feed bar (3), and these levers (4) are each connected up by means of a longitudinal guide (7). It is particularly expedient if each of the pivoting levers (4) engaging on one particular feed bar (3) are connected to one another mechanically, in particular by means of a tie bar (8) and so as to be rotatable relative to the said tie bar and can thus be moved synchronously. This provides an effective drive, particularly for the gripping movement, which can be kept free from backlash in a simple manner and takes up little space. <IMAGE>

Description

The invention relates to a device for the gradual advancement of workpieces with two gripper parts which can be moved back and forth in the feed direction for gripping the workpieces and which can be moved alternately for gripping the workpieces toward one another and for advancing together in the feed direction and then by a movement apart and a return movement are adjustable again in the starting position.

Such a device is known for example from DE 28 52 929. For the movement of the gripper rails towards one another, that is to say the gripping movement, a mechanism arranged below the plane of the gripper rails is provided with a cam disc that can be rotated about a horizontal axis and a vertically movable plunger that opposes two by means of a toothing drives rotatable gears, which in turn mesh by means of racks located on the gripper rails. The shafts of the gear wheels must be guided approximately over the length of the gripper rail in order to be able to drive a plurality of gear wheels at a distance from one another for uniform lateral movement of the respective gripper rail.

The arrangement, especially of the gears and the shaft connecting them, takes up a considerable height below the gripper rails. In addition, the entire drive is a complex mechanism, which has an unfavorable efficiency due to the multi-interacting teeth and the cam.

Instead of the gears, swivel levers have already been provided on the continuous shaft in order to carry out the gripping movements of the gripper rails. As a result, however, the shaft extending over a large part of the length of the gripper rails remains necessary and a large number of bearing points for the individual levers is necessary, which in turn affects the efficiency of the entire drive.

The invention is therefore based on the object of providing a device of the type mentioned at the outset in which the overall height in the gripping region of the gripper rails is reduced and the efficiency is nevertheless improved as far as possible.

This object is achieved in that the pivotable ends or end regions of at least two levers which can be pivoted parallel to one another in the plane of movement of the gripper rails or a plane parallel to them act on each gripper rail, that these levers of the one gripper rail are pivotable in opposite directions to those of the other gripper rail and that the levers are each coupled to the gripper rail via a longitudinal guide.

Since the levers acting as rockers can be pivoted approximately in the plane of movement of the gripper rails or parallel to them, i.e. their swivel axes are approximately perpendicular to the plane within which the gripper rails are moved, the shaft which runs at a distance below the gripper rails and thus also the shaft for them is eliminated required space. In addition, of the pivoting path of the pivotable lever, that section can be used when pivoting the gripper rails that causes the most favorable lever transmission and force transmission in the gripping direction, so that there is also a favorable efficiency. Since fewer bearings and sliding points are required, the efficiency is also favored and more accuracy can be achieved by reducing or eliminating play. Overall, the mechanism for opening and closing the gripper rails is simplified, making it less prone to failure.

A very significant simplification of the entire drive and improvement of the efficiency is obtained if the levers which act indirectly on a gripper rail are mechanically connected to one another by a pulling and / or pushing element, in particular a rod, and can be moved synchronously. This eliminates the need for complex synchronization of the individual pivotable levers and simplifies the transmission of force between a drive and the pivot levers.

The fixed, pivotable levers can be arranged on the sides of the gripper rails facing away from one another - in particular at a distance from them - or in each case in the space between the gripper rails. The former variant has the advantage that the space between the gripper rails remains free, that is to say the gripping of workpieces cannot be affected in any way by drive means. The arrangement of the levers in the space between the gripper rails - of course outside or below their gripping areas - has the advantage, even under very cramped conditions, of being able to carry out the advantageous type of drive with such pivotable levers that can be pivoted parallel to the plane within which the Gripping movements take place.

An embodiment of the drive of very considerable importance can consist in that the pivotable levers are held in the gripping position by a hydraulically or pneumatically acting or mechanical spring or similar restoring element and can be pivoted against the restoring force of the restoring element in the open position. In this way, the entire drive for the gripping movement can be made free of play, which increases the precision of the gripping movement accordingly. Furthermore, a drive is effected in one direction only because the opposite movement can be carried out by the restoring force mentioned.

A particularly space-saving arrangement results if the pulling and / or pushing element is guided on the gripper rail and the levers each pivotably engage the pulling and / or pushing element. The pull and / or push rod can be arranged below the gripper rail. In particular, it is possible that the gripper rail carries or has, at least in regions, a U-shaped or C-shaped cross-sectional profile in which the pull and / or push rod fits. It then practically forms a unit with the gripper rail, so it does not require any additional space and can carry out the synchronization of the respective pivoting levers effectively and at the point where the corresponding adjustment forces are to be transmitted to the gripper rail. Furthermore, this way the pull or push rod is well protected against dirt or damage.

A modified embodiment for the smoothest possible relative displacement movement between gripper rail and pull and / or push rod can be achieved in that the gripper rail has a guide rail on which a carriage attached with the pull and / or push rod engages. This allows a ball or roller guide to be provided between the carriage and the guide rail. However, a sliding fit is also conceivable in particular when using a U-shaped or C-shaped cross-sectional profile.

The pulling and / or pushing elements for the two gripper rails can be connected to one another outside the gripping region, in particular they can have a gripper crossbar connecting them, and a single drive can be provided for actuating the swivel levers. The arrangement of the rockers or levers ensures that the gripper rails each perform opposite movements for gripping the workpiece and for releasing it; nevertheless, with the aid of the gripper crossmember mentioned, this partially opposite movement of all levers and tension elements can be carried out with a single drive. This in turn saves space and the synchronization is achieved very easily with a backlash-free drive. The connection of the two pulling elements of the two gripper rails to one another and the possibility of thereby requiring only a single drive for their movement is therefore of particularly advantageous importance.

To actuate the pulling element or elements, a cam or link plate arranged outside the gripping area and a rocker can be provided, which rocker from the cam or link plate in the sense of a longitudinal movement of the Drawbars is pivotable, the curve or backdrop of the cam being arranged so that the gripping movement is adapted in time to the feed movement of the gripper rail. The traverse for connecting the rods and the cam disc provided for their drive can be arranged on extensions of the tie rods. They are therefore outside the area where the respective workpieces have to be gripped, that is, no additional space is required for this drive within a press or other machine tool.

The gripper rails can in turn be connected to one another outside the gripping area, in particular in the area of the extensions of the tie rods, by means of a feed traverse or the like and have a common feed drive. Thus, the advantage that is provided by a single drive is also used for the feed movement of the gripper rails.

Further embodiments of the drive means for the gripper rails in the feed direction and also in the gripping movements are the subject of claims 13 to 27. Claim 15 specifies a measure by which the overall height of the device can be kept as small as possible.

The claims 16 to 18 contain advantageous measures with which the respective stroke of the feed movement or the gripping movement can be changed in a simple manner within the drive, wherein a single adjustment device is sufficient due to the advantageous transmission of the drives to the feed on the one hand and with the help of other adjustment movement, on the other hand, to change the dimensions of the gripping movement.

Claim 19 contains a combination of features by which the attack of the gripping plunger interacting with the pull rods on the associated cam disc is free of play, without any measures being required for readjustment. Any wear is automatically compensated for by the restoring force of the spring or the restoring element.

The claims 20 and 21 contain expedient constructive designs of the connection between the slide actuated by the coupling gear and the tie rods or the gripper rails, the guides or guide slots running in the direction of extension of the crossbars the relative movements of the gripper rails and thus also the tie rods towards and away from each other despite enable common drive with these trusses.

In the claims 22 to 27 features and measures of an approximately modified embodiment of the coupling gear for driving the gripper rails and the tie rods are specified, but this modified coupling gear corresponds kinematically to that of the preceding claims. By moving the tappets in a matching plane - even though the cams are on top of each other in different planes - the overall height of this coupling gear or drive for the gripper rails and the tie rods is reduced even further.

Especially when combining one or more of the features and measures described above and contained in the claims, there is a device for detecting and gradually advancing workpieces, which is simple in construction, has a simple drive mechanism, nevertheless enables precise synchronous movements and therefore good efficiency and has a low susceptibility to failure.

At the same time, the space requirement of the device is small, especially where the workpieces have to be gripped or released, while the drive is provided primarily for opening and closing the gripper rails, but also for their feed outside a corresponding processing machine, in particular a press can.

Fig. 1

eine Ansicht einer Presse, an welcher eine erfindungsgemäße Vorrichtung zum schrittweisen Vorschieben von Werkstücken angeordnet ist, die dabei im Längsschnitt dargestellt ist, wobei der zum Erfassen der Werkstücke dienende Teil der Greiferschienen innerhalb der Presse und der Antrieb für die Greiferschienen sowohl in Vorschubrichtung als auch für die Greifbewegungen außerhalb der Presse an dieser befestigt vorgesehen sind,

Fig. 2

eine Draufsicht der Anordnung gemäß Figur 1, wobei Ständer der Presse oder dergleichen Bearbeitungsmaschine im Querschnitt erkennbar sind und schwenkbare Hebel für die Bewegungen der Greiferschienen an diesen Maschinenteilen gelagert sind,

Fig. 3

in vergrößertem Maßstab und teilweise im Schnitt einen schwenkbaren Hebel mit seiner Lagerung an einem Presseständer und mit dem Angriff seines freien verschwenkbaren Endes an einer Greiferschiene,

Fig. 4

einen Querschnitt durch den Antrieb der Greiferschienen,

Fig. 5

eine Draufsicht des Antriebes für den Vorschub und die Rückzugsbewegung der Greiferschienen gemäß der Schnittlinie V-V in Figur 4,

Fig. 6

einen um 90° verdrehten Schnitt durch den Antrieb für die Greiferschienen gemäß der Linie VI-VI in Figur 4,

Fig. 7

eine etwa der Figur 5 entsprechende Draufsicht des Antriebes für die Greifbewegungen der Greiferschienen, wobei die für die Greifbewegung dienende Kurvenscheibe in einer höheren Ebene als die in Figur 5 dargestellte Kurvenscheibe für die Vorschubbewegung angeordnet ist,

Fig. 8

einen Querschnitt einer abgewandelten Greiferschiene mit einer an ihr befestigten Führungsschiene, gegenüber welcher ein Wagen in Längsrichtung verschiebbar ist, an dem eine Zugstange und an deren Unterseite ein schwenkbarer Hebel befestigt sind,

Fig. 9

eine Draufsicht der Greiferschiene gemäß Fig. 8, wobei der aus dieser Sicht unter ihr befindliche Führungswagen gestrichelt angedeutet ist,

Fig. 10

eine Draufsicht eines abgewandelten Antriebes für den Vorschub und die Rückzugsbewegung der Greiferschienen, wobei eine Tellerkurvenscheibe mit aus der Scheibe hochstehendem Führungswulst für den Angriff der entsprechenden Vorsprünge eines Vorschubstößels vorgesehen ist,

Fig. 11

einen Querschnitt des Antriebes gemäß Fig. 10 entsprechend der Schnittlinie XI:XI in Fig. 10,

Fig. 12

eine etwa der Fig. 10 entsprechende Draufsicht (bei teilweise geschnittenem Gehäuse) des Antriebes für die Greifbewegungen der Greiferschienen, wobei die für die Greifbewegung dienende Kurvenscheibe in Gebrauchsstellung in einer höheren Ebene als die in Fig. 10 dargestellte Kurvenscheibe für die Vorschubbewegung angeordnet ist, sowie

Fig. 13

einen Querschnitt gemäß der Linie XIII:XIII in Fig. 12.

Exemplary embodiments of the invention are described below with reference to the drawing. It shows in a partially schematic representation:

Fig. 1

a view of a press on which a device according to the invention for the gradual advancement of workpieces is arranged, which is shown in longitudinal section, the part of the gripper rails used for gripping the workpieces inside the press and the drive for the gripper rails both in the feed direction and for the gripping movements are provided attached to the outside of the press,

Fig. 2

2 shows a top view of the arrangement according to FIG. 1, the stand of the press or similar processing machine being recognizable in cross section and pivotable levers for the movements of the gripper rails being mounted on these machine parts,

Fig. 3

on an enlarged scale and partially in section, a pivotable lever with its bearing on a press stand and with the attack of its free pivotable end on a gripper rail,

Fig. 4

a cross section through the drive of the gripper rails,

Fig. 5

4 shows a plan view of the drive for the feed and the retraction movement of the gripper rails according to the section line VV in FIG. 4,

Fig. 6

4 shows a section rotated by 90 ° through the drive for the gripper rails according to line VI-VI in FIG. 4,

Fig. 7

5 shows a plan view of the drive corresponding to FIG. 5 for the gripping movements of the gripper rails, the cam disc serving for the gripping movement being arranged in a higher plane than the cam disc shown in FIG. 5 for the feed movement,

Fig. 8

2 shows a cross section of a modified gripper rail with a guide rail attached to it, against which a carriage can be displaced in the longitudinal direction, on which a pull rod and on the underside of which a pivotable lever are fastened,

Fig. 9

8, a top view of the gripper rail according to FIG. 8, the guide carriage located below it from this view being indicated by dashed lines,

Fig. 10

3 shows a plan view of a modified drive for the feed and the retraction movement of the gripper rails, a plate cam disk with a guide bead protruding from the disk being provided for attacking the corresponding projections of a feed plunger,

Fig. 11

10 shows a cross section of the drive according to FIG. 10 along the section line XI: XI in FIG. 10,

Fig. 12

a top view corresponding to FIG. 10 (with a partially sectioned housing) of the drive for the gripping movements of the gripper rails, the cam disc serving for the gripping movement being arranged in a higher level than the cam disc shown in FIG. 10 for the feed movement in the position of use, and

Fig. 13

a cross section along the line XIII: XIII in Fig. 12.

In the various exemplary embodiments described below, parts that are the same or have the same function, the structural design of which is different, are each provided with the same reference numbers.

A device, designated as a whole by 1, is used for the gradual advancement of workpieces 100, for example within a press 2, where these workpieces are subjected to an additional machining operation after each such feed movement.

For this purpose, the device 1 has two parallel gripper rails 3 which can be moved and retracted in the feed direction according to the arrow PF1 in FIG. 2 and on which gripper parts 3a are provided as grippers for gripping the workpieces 100 in a known manner.

To grasp such workpieces 100, the gripper rails 3 can be moved towards one another and can be moved away again for releasing, i.e. the gripper rails 3 make a total of four different movements, namely a gripping movement in which the gripper rails 3 are moved towards one another, a feed movement, an opposite movement of the gripper Opening movement and a return movement opposite to the feed movement in the starting position. The gripper rails 3 are alternately movable towards one another for gripping the workpieces 100 and can be moved together in the feed direction for advancement and then in turn can be moved away from one another and finally adjusted back together in the starting position.

For the above-described different movements, the pivotable ends 5 or end regions of each of two levers 4, which can be pivoted parallel to one another in the plane of movement of the gripper rails 3 or a plane parallel to them, act on each gripper rail 3, as can be seen above all from FIGS. 2 and 3. The levers 4 of the one gripper rail 3 can be pivoted in the opposite direction to those of the other gripper rail 3 in order to alternately move the two gripper rails 3 towards and away from one another. So that this movement can be carried out largely independently of the feed movement, the levers 4 are each coupled to a longitudinal guide 7 of the gripper rails 3 via a sliding element 6. Thus, the gripper rails 3 can also be moved relative to the articulation points of the ends 5 of the levers 4 in the feed direction or in the opposite direction.

The swiveling levers 4 each engaging on a gripper rail 3 are mechanically connected to one another by a pull rod 8 according to FIGS. 1 to 3 and can therefore be moved synchronously. A push rod or another pulling element would also be conceivable, but a pulling rod is particularly cheap because it allows good synchronization of the two pivoting levers 4 acted upon by it with good power transmission and precise guidance at the same time.

According to FIG. 2, the fixed pivot bearings 9 of the pivotable levers 4 are on the respective in the exemplary embodiment sides of the gripper rails 3 facing away from one another are arranged at some distance from them. However, it would also be conceivable to provide these pivotable levers 4 in the space between the two gripper rails 3 if the space available, for example, in a press 2 or similar manufacturing machine would be smaller than is the case with the arrangement according to FIG. 2.

FIG. 3 shows that the pivotable levers 4 are held in the gripping position by a hydraulically or pneumatically acting or mechanical spring or the like restoring element 10 and can be pivoted against the restoring force of the restoring element 10 in the open position. The restoring element 10 can be seen below a shaft 11 which can be rotated in the fixed pivot bearing 9 relative to rolling bearings or the like and which carries the pivot arm 4 on its opposite part which projects above the bearing 9. This arrangement therefore means that the pivoting of the pivot lever 4 only has to be driven in one direction, while the opposite movement is brought about by the restoring element 10. This results in freedom of play for the drive of the swivel levers and thus the execution of the gripping movement, that is to say a high degree of accuracy.

The pull rod 8, which connects the two swivel levers 4 to one another, on which, conversely, the swivel levers 4 are rotatably supported with their free end 5, is guided on the gripper rail 3 and can therefore perform a relative sliding movement with respect to the gripper rail 3 or the gripper rail 3 can can be moved in relation to this tie rod 8 in its longitudinal direction. The gripping movements can thus be transmitted from the swivel levers 4 to the gripper rail via the pull rod, the pull rod 8 synchronizing these movements of the swivel levers 4 in a simple manner, while independently of this, the feed movement of the gripper rails 3 is still possible.

It can be seen above all in FIG. 3 that the pull rod 8 is arranged below the gripper rail 3. Here, the gripper rail 3 carries, as a longitudinal guide 7, at least in some areas, a U-shaped or C-shaped cross-sectional profile, which can be connected to it, for example, by screws 12 and into which the pull rod 8 fits in a sliding fit. With a few parts, therefore, a synchronous movement of the swivel lever 4 can be effected and transmitted in the sense of a gripping movement to the gripper rails 3, which, however, can also perform feed and retraction movements relative to these swivel levers 4 and the pull rod 8 that synchronizes them.

In the exemplary embodiment according to FIGS. 8 and 9, the gripper rail 3 has a somewhat modified longitudinal guide 7, which consists in that a guide rail 3a is attached to the gripper rail 3, on which a carriage 3b connected to the pull and / or push rod 8 engages . It can be seen above all in FIG. 8 that balls 3c can be arranged between the carriage 3b and the guide rail 3a in order to keep the friction as low as possible. The length of the guide carriage 3d oriented in the sliding direction can be seen in FIG. 9. Furthermore, seals 3c can be seen which protect the entire longitudinal guide 7 from contamination. Then, on the underside of the pull rod 8, the pivotable lever 4 again engages in a manner not shown, i.e. in this regard, the lever 4 corresponds to the arrangement in FIG. 3.

Above all in FIG. 2 it is shown that the tie rods 8 for the two gripper rails 3 are connected to one another outside the gripping regions, specifically via a connecting link Gripper crossbeam 13, so that a single drive, shown in more detail in FIGS. 6 and 7 and also FIGS. 12 and 13, there, designated 14 as a whole, is sufficient to actuate the swivel lever 4.

According to FIGS. 4 and 7, a cam or link plate 15 arranged outside the gripping area and a rocker 16 acted upon by it are provided for actuating the pull rods 8, which rocker 16 can be pivoted by the cam or link plate 15 in the sense of a longitudinal movement of the pull rods 8 , wherein the curve or backdrop of the cam 15 is arranged so that the gripping movement is adapted in time to the feed movement of the gripper rails 3 to be explained, that is, the desired chronological order of these movements is maintained. The gripper crossbar 13 for connecting the tie rods 8 and the cam 15 provided for their drive are provided acting on extensions of the tie rods 8, these extensions being connected to the drive 14 outside the frame of the machine or press 2.

In Fig. 1, 2 and 6 you can also see that the gripper rails 3 are in turn offset outside of the gripping area and with respect to the tie rods 8, are connected to each other by a feed crossmember 13a or a comparable coupling member and can therefore also have a common feed drive , which can act simultaneously and synchronously on both gripper rails 3 via this feed crossmember 13a.

One carriage 25 is connected to the tie rods 8 via the gripper crossmember 13 and the other carriage 25 is connected to the gripper rails 3 via the feed crossmember 13a. It can be seen above all in FIG. 2 that the gripper crossmember 13 and the feed crossmember 13a are each one in their direction of extension transversely or at right angles to the tie rods 8 and to the gripper rails 3 have a guide in the form of a guide slot 13b, in which a projection 13c connected to the respective tie rod 8 or gripper rail 3 engages.

Thus, the tie rods 8 with respect to the gripper crossmember 13 and the gripper rails 3 with respect to the feed crossmember 13a can carry out the required relative movements when changing their mutual distance, while on the other hand they are moved in their longitudinal extension direction via these crossmembers 13 and 13a.

According to FIGS. 4 and 5 and FIGS. 10 and 11, a cam or link plate 17 is also provided for the advance of the gripper rails 3, the drive axis or shaft 18 of which corresponds in the exemplary embodiment to that for driving the cam plate 15 for driving the pull rod 8 4, 11 and 13, one and the same shaft 18 is provided as the main shaft for both cams 15 and 17, which is connected to an angular gear 20 according to FIG. 1 via a propeller shaft 19, with which the crankshaft or the drive of the press 2 can be used for this drive of the gripper rails 3. A positively controlled drive designed in this way means a maximum number of strokes, since an absolute synchronous operation between press and device is realized.

The control cams of the two cams 15 and 17 are offset from one another and configured in their curvature in such a way that the rocker 16 driven by them for the gripping movement on the one hand and the rocker 21 for the advancing movement or retracting movement on the other are coordinated in time, that is to say at least for one Some are staggered in time, each in the final phase one movement can overlap the other movement. In FIGS. 5 and 7 it can be seen that the rockers 16 and 21, each driven by the cam disks 15 and 17, are each pivotably connected to a tappet 23, which cooperates with the cam disk via a projection 22 or the like, this being connected to the respective cam disks 15 and 17 interacting gripping plungers 23a and feed plungers 23b according to FIG. 4 are arranged in different planes parallel to one another approximately one above the other. The plungers 23a and 23b are in turn coupled via a sliding block 24 or the like to the rocker 16 or 21 and thus on the one hand to the tie rods 8 and on the other hand to the gripper rails 3, but between the rockers 16 and 21 and the rod-shaped parts driven by them a carriage 25 to be described (see in particular FIGS. 4 to 7) is also arranged.

The axis of rotation of the cams 15 and 17 formed by the main shaft 18 is arranged at right angles to the plane in which the gripper rails 3 can be moved, that is to say vertically in the exemplary embodiment, as shown in FIGS. 1 and 4. The overall height is correspondingly low because flat and thus low-height cams 15 and 17 can be used.

In the device 1 according to the exemplary embodiments it is provided that the stroke of the gripper rails 3 in the feed direction on the one hand and in the gripping movement direction on the other hand can be changed, that is to say the dimensions of the respective movements can be changed and adjusted. For this purpose, the drive for the gripper rails 3 and / or the swivel levers 4 or the pull rod 8 each have an adjusting device to be explained in more detail, with which the feed of the gripper rails 3 or the Movement of the gripper rails 3 towards one another can be changed with regard to their stroke or their dimension.

In Figures 4 to 7 and 10 to 13 it is shown that the point of attack 26 on the rocker 15 or 17 actuated rocker 16 or 21 for coupling to the gripper rail 3 or the pull rod 8 - in each case via the slide 25 - in the longitudinal direction of the Swing arm is adjustable to change the effective swing arm. One can see in FIGS. 5 and 7 in dashed lines an elongated slot 27 in both rockers 16 and 21, within which the point of attack 26 still to be described can be adjusted in the longitudinal direction of the respective rocker. According to FIG. 4, the elongated slot 27 is not formed through the entire thickness of the swing arm, but rather is approximately groove-shaped.

Specifically, it is provided that in the long slot 27 of the rockers 16 and 21 a sliding block 28 is slidably provided, which by means of a spindle 29 arranged on the respective slide 25 and a nut 31 acting on it via a pivot pin 30 in the longitudinal direction of the rocker 16 or 21 is adjustable. It can be seen in FIG. 4 that the adjusting spindle 29, which is also indicated in terms of its end in FIGS. 5 and 7, is mounted on the underside of the respective slide 25, but protrudes over the slide in order to be detected at the projecting end for the adjusting rotary movement to be able to.

The spindle 29 is thus arranged in each case in the slide 25 adjustable in the feed direction of the gripper rails 3 or the pull rods 8 and the nut 31 is adjustable in a corresponding recess in the slide 25 on the spindle 29 by its rotation. Since the slides 25 are coupled to the gripper rail 3 or the pull rod 8, affects the adjustment of the nut and thus the sliding block in the desired stroke adjustment. The closer the sliding block 28 is adjusted with the aid of the nut 31 and the spindle 29 to the pivot bearing 32 of the respective rocker 16 or 21, the shorter the respective movements of the gripper rail 3 or the pull rod 8, the shorter movement of the pull rod 8 also causes a smaller pivoting path of the pivot lever 4 and thus a smaller gripping movement of the gripper rails 3.

In FIG. 5 it can be seen that the cam disk 17 for the advance of the gripper rails 3 is arranged on the feed tappet 23b between two cam rollers 22, which act on these two cam rollers 22 at the same time, and one cam roller 22 for the feed motion and the other cam roller 22 for the retraction motion acted upon. The feed movement and the withdrawal movement of the gripper rail 3 are therefore both positively controlled.

The cam plate 15 for the adjustment movement of the tie rods 8, however, acts only on a cam roller 22 located on the associated gripping tappet 23a according to FIG. Correspondingly precise gripping movements can be carried out. In this case, the tappets 23a and b are advantageously arranged immediately above or below the cam disks 15 and 17 and have elongated slots 33 which permit their adjustment movement relative to the main shaft 18 passing through them.

According to the above, there are between the exemplary embodiments of the drive 14 in FIGS. 4 to 6 on the one hand and in FIGS. 10 to 13 on the other hand Explanations significant similarities. However, there are some differences. In the exemplary embodiment according to FIGS. 10 to 13, it is primarily provided that the gripper tappet 23a and the feed tappet 23b are arranged in the same plane and, with projections or cam rollers 22 projecting opposite them, on the cam disks 15 and 17 mounted coaxially one above the other on the same shaft 18 attack. 4, the plungers 23a and 23 are at different heights and thus require a correspondingly greater overall height, in the exemplary embodiment according to FIGS. 10 to 13 they are located in one and the same plane, which further reduces the overall overall height of the drive 14.

It is clear from FIGS. 10 and 12 that the gripping plunger 23a and the feed plunger 23b have guides which run at an angle, in the exemplary embodiment at right angles, to one another, e.g. Linear roller guides 23c are mounted for longitudinal displacement. The longitudinal centers of these guides 23c each intersect the center of the shaft 18 and run radially thereto, as can be clearly seen from FIGS. 10 and 12.

Furthermore, it can be seen that these guides 23c are oriented at an angle, in the exemplary embodiment at 45 °, to the direction of movement of the slides 25, and the rockers 16 and 21, which are actuated by the plungers 23a and 23b, act on the slides 25 from two under a corresponding angle to each other arms exist, so that despite the somewhat different arrangement of the plungers 23a and 23b on the slide 25, the same transmission movements occur as in the above-described embodiment according to FIGS. 4 to 6, that is to say in FIGS. 10 to 13 a kinematic 4 to 6 matching coupling gear is shown. It is in the left part FIGS. 10 and 12 each show visible slides 25 for the advance of the gripper rails 3 in the middle position of this advance, that is to say they can be shifted further to the right and to the left, while the other slide 25 assumes its left end position.

So that the feed tappet 23b does not have to extend beyond the diameter extension of the cam disk 17, which would make it considerably more difficult to arrange the two tappets 23a and 23b in one and the same plane, the cam disk 17 is in this embodiment according to FIGS. and retraction movement of the gripper rails 3 is designed as a plate cam disc with a raised guide bead 17a, on which guide bead 17a a cam roller 22 or similar projection of the feed tappet 23b engages on both sides. The guide bead 17a is thus between the two cam rollers 22, so that it can cause reciprocating movements on the feed tappet 23b.

When comparing FIGS. 11 and 13, it can be seen that the cam rollers 22 on the feed tappet 23b protrude below this feed tappet 23b to the cam disk 17 underneath, while the cam roller 22 on the gripping tappet 23a - according to FIG. 13 - follow it protrudes above to get into the area of the corresponding edge of the cam 15. Thus, both plungers 23a and 23b can lie and work in the flatest possible design of the entire drive 14 in the same plane.

As in the first described embodiment, the slides 25 in turn directly or indirectly engage the cross members 13 and 13a in order to carry out the correspondingly coordinated feed and gripping movements and the subsequent opening and retracting movements, with all these movements due to the features and items described above, a single drive via the shaft 18 is sufficient.

The device 1 for the step-by-step advancement of workpieces, for example in a press 2 or similar production machine or also for other machining operations to be carried out step-by-step, thus has two gripping parts 3 a or gripping areas for gripping the workpieces 100 that have gripper rails 3 that are used to grasp the Workpieces towards one another and for advancing in this gripping position can be moved together in the feed direction and then release the workpieces by a movement apart and can be adjusted back to the starting position by a return movement. Each gripper rail 3 is engaged by the pivotable ends 5 or end regions of at least two levers 4 which can be pivoted in the plane of movement of the gripper rail 3 or in a plane parallel thereto, these levers 4 of the one gripper rail 3 being pivotable in opposite directions to those of the other gripper rail 3, and these Levers 4 are each coupled via a longitudinal guide 7. It is particularly expedient if pivoting levers 4 each engaging on a gripper rail 3 are mechanically connected to one another, in particular by means of a pull rod 8, and can thus be moved synchronously. This results in an effective drive that is easy to keep free of play, especially for the gripping movement, which takes up little space.

Claims (27)

Device (1) for the gradual advancement of workpieces with two gripper parts or areas which can be moved back and forth in the direction of advance for gripping the workpieces and which alternately can be moved towards each other for gripping the workpieces and can be moved together in the advance direction and then advanced can be adjusted back to the starting position by a movement apart and return movement, characterized in that on each gripper rail (3) the pivotable ends (5) or end regions of at least two levers (parallel to one another in the plane of movement of the gripper rail (3) or a plane parallel to it) 4) attack that these levers (4) of one gripper rail (3) can be pivoted in the opposite direction to those of the other gripper rail (3) and that the levers (4) are coupled via a longitudinal guide (7) of the gripper rails (3). Device according to claim 1, characterized in that the levers (4) which act indirectly on a gripper rail (3) are mechanically connected to one another by a pulling and / or pushing element, in particular a rod (8), and can be moved synchronously. Apparatus according to claim 1 or 2, characterized in that the fixed pivot bearings (9) of the pivotable levers (4) on the sides of the gripper rails (3) facing away from one another - in particular at a distance from these - or in each case in the space between the gripper rails ( 3) are arranged. Device according to one of claims 1 to 3, characterized in that the pivotable levers (4) are held in the gripping position by a hydraulically or pneumatically acting or mechanical spring or the like restoring element (10) and can be pivoted in the open position against the restoring force of the restoring element (10) are. Device according to one of claims 1 to 4, characterized in that the pulling and / or pushing element (8) is guided on the gripper rail (3) and the levers (4) are each rotatable or pivotable on the pulling and / or pushing element attack Device according to one of claims 1 to 5, characterized in that the pull and / or push rod (8) is arranged guided below the gripper rail (3). Device according to one of claims 1 to 6, characterized in that the gripper rail (3) carries, at least in regions, a U-shaped or C-shaped cross-sectional profile (11) into which the pull and / or push rod (8) fits. Device according to one of claims 1 to 7, characterized in that the gripper rail (3) has a guide rail (3a) on which a carriage (3b) connected to the pull and / or push rod (8) engages. Device according to one of claims 1 to 8, characterized in that the pulling and / or pushing elements for the two gripper rails (3) are connected to one another outside the gripping region, in particular have a gripper cross member (13) connecting them, and a single drive (14) for actuating the swivel lever (6) is provided. Device according to one of claims 1 to 9, characterized in that a cam or link plate (15) arranged outside the gripping area and a rocker arm (16) are provided for actuating the pulling element (s) (8), which rocker arm (16) from the Cam or link plate (15) can be pivoted in the sense of a longitudinal movement of the tie rods (8), the curve or link of the cam plate (15) being arranged in such a way that the gripping movement is temporally adapted to the feed movement of the gripper rails (3). Device according to one of claims 1 to 10, characterized in that the gripper crossmember (13) for connecting the tie rods (8) and the cam disc (15) intended for their drive are arranged to act on extensions of the tie rods (8). Device according to one of claims 1 to 11, characterized in that the gripper rails (3) are in turn connected to one another outside the gripping area by a feed crossmember (13a) or the like and have a common feed drive. Device according to one of claims 1 to 12, characterized in that a cam or link plate (17) is provided for the advance of the gripper rails (3), the drive axis or shaft (18) thereof in particular with that for driving the pull rod (8) coincides and that the control cams of the two cams (15, 17) are offset from one another in such a way that the rocker (16) driven by them for the gripping movement on the one hand and the rocker (21) for the advancing movement or retraction movement on the other are coordinated with one another in time. Device according to one of claims 1 to 13, characterized in that the rockers (16, 21) each driven by the cam disks (15, 17) each have a gripping tappet (23) and which cooperate with the cam disk via a cam roller (22) or the like Feed plungers (23b) are pivotally connected and in turn are coupled to the rocker (16, 21) in particular via a sliding block (24) or the like. Device according to one of claims 1 to 14, characterized in that the axis of rotation of the cam discs (15, 17) are arranged at right angles to the plane in which the gripper rails (3) can be moved, in particular are arranged vertically to one another. Device according to one of claims 1 to 15, characterized in that the drive for the gripper rails (3) and / or the swivel lever (4) or the pull rod (8) has an adjusting device with which the feed of the gripper rails (3) and / or the movement of the gripper rails (3) towards one another can be changed. Apparatus according to claim 16, characterized in that the point of attack (26) on the rocker arm (16, 21) actuated by the cam disc (15, 17) for coupling to the gripper rail (3) or the pull rod (8) in the longitudinal direction of the rocker arm Change of the effective swing arm is adjustable. Device according to one of claims 1 to 17, characterized in that a sliding block (28) is provided in an elongated slot (27) of the rocker arm (16, 21), which sliding block (28) is arranged on the slide (25) and a on it engaging nut (31) is adjustable in the longitudinal direction of the rocker, the spindle (29) in a slide (25) adjustable in the direction of advance of the gripper rails (3) and / or pull rods (8) is arranged and the nut on this spindle (29) is adjustable and this slide (25) with the gripper rails (3) and / or the pull rod ( 8) is coupled. Device according to one of claims 1 to 18, characterized in that the cam disc (17) for the advance of the gripper rails (3) is arranged on the advance plunger (23b) between two cam rollers (22), acting on these two at the same time, and for the Feed movement acts on one cam roller and the other cam roller for the retraction movement. Device according to one of claims 1 to 19, characterized in that the cam disc (15) for the adjustment movement of the pull rod (8) acts on a cam roller (22) located on the gripping plunger (23a) and the transmission of the movement of the pull rod (8) is carried out the restoring force of the spring or the restoring element (9) acting against the adjusting movement on the swivel levers (4) is free of play. Device according to one of claims 1 to 20, characterized in that one slide (25) via the gripper crossbar (13) with the pull rods (8) and the other slide via the feed crossbar (13A) with the gripper rails (3 ) connected is. Device according to one of claims 1 to 21, characterized in that the gripper crossmember (13) and the feed crossmember (13a) each extend transversely or at right angles to the tie rods (8) and to the gripper rails (3) in their direction of extension Guide or have a guide slot (13b), wherein a with the respective tie rod (8) or gripper rail (3) connected projection (13c) engages. Device according to one of claims 1 to 22, characterized in that the gripping plunger (23a) and the feed plunger (23b) are arranged in the same plane and, with projections or cam rollers (22) projecting opposite them, on cam disks (15, 17) attack. Device according to one of claims 1 to 23, characterized in that the gripping plunger (23a) and the feed plunger (23b) are mounted so as to be longitudinally displaceable in guides which run at an angle to one another, in particular at right angles to one another, in particular in linear roller guides (23c). Device according to one of claims 1 to 24, characterized in that the longitudinal centers of the guides (23c) for the plungers (23a, 23b) each intersect the center of the shaft (18) and run radially thereto. Device according to one of claims 1 to 25, characterized in that the guides (23c) are oriented at an angle, in particular at 45 °, to the direction of movement of the slides (25) and acted upon by the plungers (23a and 23b) wings (16, 21) engaging the carriage (25) each consist of two arms at an appropriate angle to each other. Device according to one of the preceding claims, characterized in that the cam disc (17) for the advancing and retracting movement of the gripper rails (3) as a disc cam disc with a raised guide bead (17a) is formed, on each of which a cam roller (22) or similar projection of the feed tappet (23b) engages in such a way that the guide bead (17a) is located between these two cross rollers (22) or the like.

Images