EP0650781A2 - Driving device for a multi-axle transport of work pieces in a transfer press - Google Patents

Abstract

The invention relates to a drive device for multi-axis transport of workpieces through successive processing steps in a forming press, in which a lifting mechanism (4) takes over the vertical drive of lifting columns (9) by means of a lever linkage (42), which is connected to the gripper rails (2, 3) are connected. An additional opening and closing mechanism causes a transverse displacement of the bearing housings (46) of the respective lifting columns (9).

Description

The invention relates to a drive device for a multi-axis transport of workpieces in a transfer press according to the preamble of claim 1.

State of the art:

In the conventional production of, for example, body sheet metal parts, these are produced in several operations on individual presses or in press lines. The degree of mechanization, ie the interlinking of the individual presses, can be very different. A transfer or step press is a single press with a certain number of tool stations connected in series, ie the work steps are combined in a single press. The workpieces are processed in successive operations, that is, several operations take place simultaneously during a press stroke. The workpieces are transported from stage to stage via a two-dimensional or three-dimensional gripper system, which is usually mechanically coupled to the ram drive. For this purpose, two gripper rails arranged parallel to each other - also called support rails - are guided on both sides over the entire length of the step press in order to move the workpieces within the press.

• Greifen der Werkstücke mittels einer Querbewegung der Greiferschiene;
• Heben des Werkstücks mittels einer Vertikalbewegung der Greiferschiene;
• Weitertransport des Werkstücks mittels einer Längsbewegung der Greiferschiene;
• Absenken der Werkstücke;
• Öffnen der Greifer;
• Rücklauf in Ausgangsstellung.

The parts are transported within the press in the classic transfer system using the following functions:

• Gripping the workpieces by means of a transverse movement of the gripper rail;
• Lifting the workpiece by means of a vertical movement of the gripper rail;
• Further transport of the workpiece by means of a longitudinal movement of the gripper rail;
• Lowering the workpieces;
• Opening the grippers;
• Return to the starting position.

In general, the gripper rail must be returned to the starting position after this three-dimensional movement. The gripper rails have special workpiece gripper systems for gripping the workpieces.

From EP 0 210 745 A2, in particular from the figure there, the basic structure of the movement scheme for a classic three-axis system has become known. The gripper rails running parallel through the press are therefore controlled three-dimensionally by a cam mechanism. The drive of the cam mechanism is mechanically coupled to the central press drive.

From DE 33 29 900 C2 a transfer system for a stepped press has also become known, in which the three-dimensional transport of the gripper rails takes place via separate drive systems. The advancing mechanism, the lifting mechanism and the tensioning or closing mechanism are each assigned their own electric drive, which carries out the respective movement process synchronously for both gripper rails via a gear arrangement. A mechanical coupling and thus a mutual positive control as in the aforementioned document EP 0 210 745 is not provided.

Object and advantages of the invention:

The invention has for its object to provide a drive device for a multi-axis transport of workpieces in such a transfer press, in which independent drives can be used for the various movement sequences, the electronically controlled synchronization of the movement sequences, in particular the feed, lifting and Have opening / closing movement of the gripper rails.

This object is achieved on the basis of a drive device according to the preamble of claim 1 by the characterizing features of claim 1.

Advantageous and expedient developments of the drive device specified in the main claim are provided in the subclaims.

The drive device according to the invention has the advantage over known systems that a very compact structure is created for a combined lifting and closing movement of the gripper rails. The gripper rails are for Carrying out the sequence of movements is mounted on so-called lifting columns, which in turn can be adjusted in their position by a vertical drive common to both gripper rails via a height-adjustable cross-beam and by an actuator for transverse displacement. The lifting and closing movements can be largely independent in their movement sequences by separate motor drive. On the other hand, the mechanical coupling and arrangement of the movement systems can directly influence the movement sequences with respect to one another, ie overlapping movements are also possible to shorten the cycle time.

The arrangement of the lifting column in a separate housing is particularly advantageous, which enables a relative movement between the lifting column and housing and thus an independent movement during the lifting process and the closing process. If, for example, the lifting column housing is moved in the transverse direction to carry out the closing movement, the lifting column can simultaneously be moved vertically within the lifting column housing.

In an advantageous embodiment of the invention, the gripper rails can be adjusted to carry out the transverse closing movement by means of separately driven threaded spindles with opposite pitch or by a belt drive or the like. The lifting column housing is provided with appropriate drive means. Passing the threaded spindles through the lifting columns also ensures a symmetrical application of force.

In an advantageous further development of the invention, the lifting process takes place via a mechanical lever linkage which is driven by a linear movement by means of a separate servo motor or the like and which brings about a lifting movement of the associated crossbar. Such a lever linkage can be arranged compactly in an associated housing in order to carry out the lifting movement of the crossbar or bearing beam connected to the lifting columns. Due to the U-shaped design of the cross-beam, it is possible to implement the invention in the smallest of spaces and with a small mass. The cross-beam also serves to horizontally support the cross-adjustable lifting columns.

Fig. 1a, Fig. 1b

ein erstes Ausführungsbeispiel für eine Antriebseinrichtung der Greiferschienen mit einem Spindelantrieb in unterer Hubstellung nach Fig. 1a und oberer Hubstellung nach Fig. 1b,

Fig. 2a

eine Draufsicht auf die Hubverstelleinrichtung mit Hebelgestänge nach Fig. 1a, 1b entlang der Schnittlinie A-A in Fig. 1a,

Fig. 2b

einen Schnitt durch das Hebelgestänge nach Fig. 1b entlang der Schnittlinie C-C,

Fig. 3a

eine alternative Ausführungsform für den Antrieb des Schließmechanismus mittels eines Riemenantriebs und

Fig. 3b

eine Draufsicht des Riemenantriebs nach Fig. 3a entlang der Schnittlinie B-B.

Further details and advantages of the invention are shown in the drawings and are specified in more detail in the exemplary embodiments explained below. Show it

Fig. 1a, Fig. 1b

1 shows a first exemplary embodiment of a drive device for the gripper rails with a spindle drive in the lower stroke position according to FIG. 1a and the upper stroke position according to FIG. 1b,

Fig. 2a

2 shows a top view of the stroke adjustment device with lever linkage according to FIGS. 1a, 1b along the section line AA in FIG. 1a,

Fig. 2b

2b shows a section through the lever linkage according to FIG. 1b along the section line CC,

Fig. 3a

an alternative embodiment for driving the locking mechanism by means of a belt drive and

Fig. 3b

a top view of the belt drive according to Fig. 3a along the section line BB.

Description of the embodiments:

The section through the end view of a step press 1 shown in FIG. 1 a shows the two gripper rails 2, 3 leading through the entire length of the step press and a lifting mechanism 4 for carrying out the lifting movement and an opening or closing mechanism 5 for carrying out the closing movement of the gripper rails 2 , 3. According to the principle of the three-axis transport in DE 38 42 182 C1, each gripper rail 2, 3 executes a transverse movement about a central axis 6, 7 with each closing operation in order to carry out the transverse closing movement in each case. The center plane of symmetry 8 consequently shifts in the transverse direction into the position 8 ', i. H. the gripper rail 2, 3 performs a transverse movement during the clamping or closing process. The arrangement of the gripper rails 2, 3 in their initial position as a set-up axis must be distinguished from this constant movement process for the transport of parts from tool stage to tool stage. Depending on the size and nature of the workpiece to be machined in the press, the respective central axis 6, 7 is brought into a fixed starting position. 1 shows the outer position of the respective central axis 6, 7 and the innermost position of the central axis 6 ', 7'. The displacement of the central axes 6, 7 takes place to set the set-up axis within such a defined range when the press is set to the workpiece to be machined.

The opening and closing device 5 responsible for the transverse movement (hereinafter referred to as "closing device") is therefore responsible both for the movement between the central symmetry planes 8, 8 'during the workpiece transport process and for the setting of the set-up axis. The innermost position of the gripper rails 2, 3 is designated 2 ', 3'. The in the 1 to 3 illustrated embodiments of the invention show the lifting mechanism 4 and the closing mechanism 5 for performing the upward and downward movement and the laterally closing movement of the two gripper rails 2, 3. The longitudinal movement of the gripper rails 2, 3 by means of an advancing mechanism is shown in FIGS to 3 not shown. It can be carried out in an analogous manner, as is shown in DE 38 42 182 C1 by the applicant. Likewise, a separate drive according to DE 33 29 900 C2 mentioned in the introduction can also be provided for the advancing mechanism.

The mutually synchronous lifting and closing movement of the two gripper rails 2, 3 takes place via a lifting column 9, which is connected in its upper region to the gripper rail 2, 3 via a slide guide 10. In the lower area, each lifting column 9 of the two gripper rails 2, 3 is mounted on a common cross-beam 11 via a respective guide carriage 12 in a guide 13 which runs transversely with respect to the longitudinal axis of the press. The guides 13 cover a travel length that allows the necessary scope for the width adjustment of the set-up axis including the closing path.

According to the representation of Figures 1a, 2a and 2b, the crossbar 11 is designed as a U-shaped component in cross section, with an upper, transverse surface section 14 for receiving the guide 13 lying thereon and two laterally downwardly extending legs 15, 15 ', on which at a distance l₁ two opposite bearing webs 16, 16 'and 17, 17' are welded. Fig. 2b shows a section A-A through the right bearing webs 16, 16 'shown in Fig. 1a.

In an upwardly open, also U-shaped housing 18, two L-shaped angle levers 19, 20 are in one each fixed bearing 21, wherein an approximately horizontally aligned lower leg 22 is connected via a bearing point 23 to the lower part of the respective bearing webs 16, 16 'and 17, 17'. An upwardly directed approximately vertical further leg 24 of each angle lever 19, 20 is connected via a respective bearing point 25 to an approximately horizontally oriented push rod 26. The push rod 26 is connected on its right drive side shown in FIG. 1a via a tab 27 with the individual joints 28, 29 to a guide head 30 which is mounted in a bearing shoe 31 on the housing 18 in a longitudinal guide 32. The guide head 30 laterally has a spindle nut 33, in which a horizontally oriented spindle 34 of a spindle drive 35 engages. The spindle drive 35 is designed as a finely adjustable electric motor or hydraulic motor and is flanged to the side of the housing 18. Another linear drive can also be provided for a linear adjustment of the guide head 30. It has a displacement measuring device 74, which detects the adjustment movement of the spindle nut 33 and thus the stroke movement.

On the side opposite the drive device 35, the push rod 26 is connected via a further articulated lever 36 to the individual joints 37, 38 with a pull tab 39, which in turn is connected to a weight compensation cylinder 40 with a piston rod 41. The cylinder 40 constantly exerts a train and thereby balances the weight of the lifting device 5. A rotary movement of the threaded spindle 34 accordingly causes a longitudinal displacement of the push rod 26 (see arrow 43), the cylinder 40 pulling on the push rod 26. A z. For example, in FIG. 1a, the longitudinal movement of the push rod 26 directed to the left causes a rotation of the two angle levers 19, 20 counterclockwise (arrow 44) and thus an upward movement of the two bearing webs 16, 16 'and 17, 17' via the lever arm 22. .

As a result, the U-shaped crossbar 11 connected to the bearing webs 16, 17 is displaced upward (arrow 45).

An opposite movement of the push rod 26 by means of the drive 35 causes the cross-beam 11 to be lowered. The lifting columns 9 transmit these lifting movements to the two gripper rails 2, 3. The lifting columns are mounted in a bearing housing 46 in a bearing bush 47.

The opening or closing movement of the two gripper rails 2, 3 takes place via the further, separate opening and closing mechanism 5, consisting of a separate drive motor 48, which may be designed as a geared motor and whose drive shaft as threaded spindles 49, 49 'extends over the entire Length of the press lock box extends. In the area of the vertical symmetry center plane 50, the drive shafts 49, 49 'are mounted in a bearing 51 and continue from there in one piece as a shaft section 49'. The drive shafts 49, 49 'consist of threaded spindles with opposite pitch. A displacement measuring device 73 is provided on the bearing housing 53, which detects the transverse displacement of the gripper rails 2, 3 and forwards the required measurement signals to the positioning motor 48. The bearing housings 46 arranged on both sides for the lifting columns 9 each have a spindle nut 52 which are in engagement with the drive shafts 49, 49 '. The end of the drive shaft 49 opposite the drive motor 48 is mounted in a bearing housing 53. Due to a reverse slope of the drive shaft 49, 49 ', the two spindle nuts 52 move in the opposite direction when the drive shaft rotates (arrow 54), so that the bearing housing 46 connected to the spindle nuts 52 and thus the lifting columns 9 and with them the gripper rails 2 , 3 are moved towards or away from each other. For this purpose, the upper cover plates 55 are designed to be displaceable relative to one another.

In order to obtain the most symmetrical and central point of engagement of the spindle nuts 52 on the bearing housing 46, their symmetry center planes intersect. In this case, the drive shaft 49 is passed through a longitudinal slot 56 with the height h 1. Since the drive shaft 49 remains in the same horizontal plane, the longitudinal slot must be equipped with a certain height h 1 in order to permit the required lifting movement of the lifting column 9.

1a also shows inner stops 57 and outer stops 58 which limit the lateral travel movement or transverse movement during the tensioning or closing process and which cooperate with the side wall of the bearing housing 46.

Fig. 1a shows the position of the lever linkage 42 such that the lower lifting position of the two gripper rails 2, 3 is reached, i. H. the drive shaft 49 is located in the upper region of the longitudinal slot 56. By pushing the thrust axis 26 in Fig. 1b in the direction of the clamping cylinder 40 (arrow 43 '), the two angle levers 19, 20 rotate counterclockwise (arrow 44), so that the bearing straps 16, 17 and thus the crossbar 11 is raised (arrow 45 '). So that the two lifting columns 9 are moved upward, so that in the illustration of FIG. 1b, the drive shaft 49 comes to rest in the lower region of the longitudinal slot 56. The two gripper rails 2, 3 are also lifted upwards by the amount of lifting of the longitudinal cross member 11.

The lifting movement by means of the lifting mechanism 4 and the opening or closing movement by means of the closing mechanism 5 can be carried out independently and overlapping in time. The locking mechanism 5 is used both to carry out the closing movement during the machining process and to adapt to the required part width when converting.

The exemplary embodiment according to FIGS. 3a, 3b shows a modified opening or closing mechanism 5 '. The lifting mechanism 4 corresponds to the exemplary embodiment according to FIGS. 1 and 2.

To carry out the closing movement both for adjustment during the workpiece transport process and for adaptation to the workpiece width as described for FIG. 1, a belt drive 60 is provided in the embodiment according to FIG. 3a in front view and FIG. 3b in plan view, which consists of a rotating belt 61 consists. To drive the rotating belt 61, a separate drive motor 62 with a displacement sensor 73 'is provided, on the drive shaft 63 of which a first deflection roller 64 is arranged. The toothed belt 61 guided over the deflection roller 64 is guided on the opposite side of the press via a second deflection roller 65 which is mounted on a bearing block 66. The bearing block 66 itself is held on a housing 68 for the locking mechanism by means of clamping screws 67. The axes of rotation of the two deflection rollers 64, 65 are vertical and are parallel to the central axes of the two lifting columns 9. As can be seen from FIGS. 3a, 3b, the bearing housing 46 for the respective lifting column 9 lies between the two belt halves 61, 61 ', according to 3b, the left bearing housing 46 is connected to the upper belt 61 via a non-positive or positive connection 69, while the right bearing housing 46 shown in FIG. 3a is connected to the lower belt 61 'via a corresponding non-positive or positive connection Connection is connected. The latter is not shown in detail due to the sectional drawings. The two opposite bearing connections with the two belt halves 61, 61 'run the two bearing housings 46 towards or away from each other. For example, the belt 61 rotates in Clockwise, the two bearing housings 46 attached to it run towards each other.

The left part of FIG. 3b shows the section BB in FIG. 3a up to the vertical symmetry center plane 50. From there, the section goes upwards, as shown in the right part of FIG. 3b, into the guide area of the right bearing housing 46. For guiding the Both bearing housings 46 are accordingly provided in the upper region of each bearing housing with a carriage 70 which has four profiled rollers 71 in its four corner regions, which engage two opposite guide rods 72, 72 '. These guide rods 72, 72 'extend over the entire required path length for carrying out the required transverse movements of the two gripper rails 2, 3.

When the drive motor 62 is actuated, the belt 61 is therefore rotated clockwise or counterclockwise, depending on the direction of rotation of the drive shaft 63, so that the bearing housings 46 fastened in opposite directions for both lifting columns 9 of the two gripper rails 2, 3 have the opening or closing movement running in the transverse direction carry out. The bearing housing 46 is guided horizontally via the carriage 70 with rollers 71 on the guide rods 72.

The invention is not restricted to the exemplary embodiments described and illustrated. Rather, it also encompasses all professional configurations within the scope of the current claim 1.

Claims (14)

Drive device for multi-axis transport of workpieces through successive processing stations of a forming press, and in particular a transfer press, two gripper rails arranged parallel to one another being provided, which are moved in the longitudinal direction by means of an advancing mechanism, in the vertical direction by means of a lifting mechanism and in the transverse direction by means of an opening or closing mechanism are movable, characterized in that for carrying out the vertical lifting movement (45) below the gripper rails (2, 3) a cross-beam (11) which can be moved up and down by means of a drivable lever linkage (42) is provided that the cross-beam (11) comes on Its upper side (14) has guide means (13) for lifting columns (9) which can be displaced thereon, on each of which a gripper rail (2, 3) is mounted so as to be transversely displaceable and that in order to carry out a transverse opening or closing movement of the gripper rails (2, 3) the opposite underlying lifting columns (9) for the gripper rails (2, 3) is assigned a common drive device (49, 61). Device according to claim 1, characterized in that each lifting column (9) is arranged in a bearing housing (46) and that the bearing housing has fastening means (52, 69) for transverse transport by means of a linear drive device (49, 61). Device according to claim 1 or 2, characterized in that the linear drive device for the lifting columns (9) or its bearing housing (46) by a threaded spindle (49) which preferably penetrates the lifting columns (9). is formed, which is in engagement with an associated spindle nut (52) on the bearing housing (46). Device according to claim 1 or 2, characterized in that the linear drive device for the transverse displacement of the lifting columns (9) is formed by a revolving belt drive (61) or the like, the lifting columns (9) or its bearing housing being fastened to opposite belt strands are. Device according to claim 4, characterized in that the bearing housing (46) comprises a slide (70) with guide rollers (71) which are supported on associated, stationary guide rods (72). Device according to one of the preceding claims, characterized in that the bearing housings (46) are supported on both sides by stops (57, 58) to limit the path. Device according to one of the preceding claims, characterized in that the cross-beam (11) connected to the lifting columns (9) is designed as a U-profile which is open towards the bottom and which extends as far as possible over the entire width of the closing box of the press and its upper surface section (14) has guide means (13) for a guide carriage (12) on the lifting columns (9) and on its lateral legs (15, 15 ') a lever linkage (42) engages for the lifting movement of the gripper rails (2, 3). Device according to claim 7, characterized in that the U-profile of the cross-member (11) is embedded in an upwardly open, likewise U-shaped housing (18) and via angle levers (19, 20) and bearing webs mounted in the housing (18) (16, 17) is movable up and down in this. Device according to claim 8, characterized in that the angle levers (19, 20) for executing the vertical movement of the crossbar (11) can be moved or pivoted via a drivable and in particular horizontally displaceable push rod (26). Device according to claim 9, characterized in that the drive for the push rod (26) takes place via an electric, servo motor (35) or positioning motor or the like with a threaded spindle (34) and spindle nut (33) or an equivalent hydraulic motor or linear drive. Device according to one of the preceding claims, characterized in that the transverse displacement of the lifting columns (9) connected to the gripper rails (2, 3) takes place on the one hand for carrying out the opening and closing movement required in the work cycle and on the other hand for adjusting the set-up axis when the workpiece size has changed. Device according to one of the preceding claims, characterized in that the lifting mechanism (4) and / or the opening and closing mechanism (5) each have a separate, preferably electrical drive without a mechanical coupling. Device according to one of the preceding claims, characterized in that the drive for the lifting mechanism (4) and / or for the opening or closing mechanism (5) and / or an advancing mechanism for the gripper rails (2, 3) takes place via a common mechanical drive . Device according to one of the preceding claims, characterized in that the lifting mechanism (4) and / or the opening or closing mechanism (5, 5 ') are each assigned measuring systems (74; 73, 73').

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