EP0125367B1 - Gripper feeding device for presses or the like - Google Patents

Description

The invention relates to a tongs feed device for metal strips; Sheet metal strips or profiles for presses, scissors or the like Drive means mediated stroke, regardless of the direction of movement, only one of the two feed tongs is set to transport.

A similar device was known from DE-OS 18 11 302, but it must be emphasized as a fundamental feature that the drive of the two feed tongs arranged at a variable distance from one another is only partially rectified over a certain distance, after the second clamping head has been put back one Performs reverse stroke with the gun open.

In general, it is contemplated that the forward and backward strokes of one chuck are equal to each other and the forward and backward strokes of the other chuck, and the forward stroke of each chuck is in phase with the backward stroke of the other chuck.

A convertible, hydraulic motor is used as the drive, a control device having a first switch which is assigned to the gripper carried by one of the clamping heads and a second switch which is assigned to the gripper carried by the other clamping head. Each of these switches can be actuated by the associated gripper and controls the function of the other gripper in such a way that when the material is clamped in a gripper, the other gripper releases the material. The drive direction is switched such that it is reversed when one of the switches is actuated by the gripping gripper assigned to it.

The positions of the clamping heads at the end of their forward and backward strokes are determined by their attack on one stop each, the stops being arranged at a distance from one another. The function of this device is to be regarded as complicated and expensive due to the simultaneous movement of the forward and reverse strokes and the resulting control effort. For this reason alone, it could not be put into practice.

Furthermore, it is known from DE-PS 1 265 106 that the two feed tongs are arranged one behind the other in the feed direction and their feed paths are also one behind the other. The drive of the pliers, however, each requires its own drive, which requires its own stop and damping system for each pliers, which, in summary, results in increased energy consumption for each pliers.

In addition, it should be noted for the aforementioned systems that the goods to be transported must be accelerated and braked linearly. This requires a high clamping or holding force of the pliers, so that the feed material does not continue to slide in the holding pliers after the feed stroke has been braked, thereby canceling the required feed tolerance.

It should also be noted that these devices generally already require a high feed force due to their linear acceleration.

Taking this into account, it is the object of this invention to name a gripper feed device of the type described in the introduction, which allows the adjustment of the feed path and its direction as well as the distance of the feed pliers to one another with minimal feed force in practically any band or strip width and thickness .

The solution to this problem provides that for the transport of the band, each feed tongs is assigned a carrying slide guided by a common guide track, each of which can be driven by a crank drive, that each crank drive consists of a crank wheel designed with an adjustable crank radius, a carrying slide for a feeding tongs and one the crank wheel with the support arm connecting the rocker arm, the crank wheels being arranged on two shafts, each of which is provided with a sprocket on the other, and both sprockets are connected by an endless drive and this is connected to the reversible drive means that the distance between the support slides from one another by a common Adjusting means for setting the crank radii synchronously, in opposite directions or diverging, via the crank arms, which each connect the crank pivot bearing and the slide pivot bearing, can be adjusted, and the path length of the forward and return runs is determined. Furthermore, it is provided that the crank wheels are arranged on the bearings of a gearbox on the rear wall, and that the adjusting means is carried in a third bearing arranged centrally between the crank bearings and ends with a bevel gear, which in turn has preset crank radii which determine the maximum tong distance to the axis of the adjusting means, arranged at right angles and coaxially, with bevel gears provided with threaded spindle, which in turn engage in this position in diametrically opposite directions, provided in slide grooves of the crank wheels in threads corresponding to the spindles, these slides, each in the opposite direction - are slidably adjustable when the drive of the bevel gear connected to the adjusting means is actuated.

The transport of the sheet metal strip through the support slides connected to the feed tongs by the drive means via a crank drive assigned to each support slide has the advantage that the linear movement of the drive means by implement in two rectified rotary movements on the crank drives, a sinusoidal course of the speed of the feed tongs over their forward and return runs.

This means a softer acceleration and a softer braking of the forward and return movement of the feed tongs. This reduces the drive power for transport, so that the drive cylinders can be selected to be smaller and the clamping forces in the feed tongs can be kept lower.

It is recommended, depending on the power requirement, to regulate the working medium for the drive means or the drive means in order to set an optimal drive power.

To increase the feed rate, it can also be provided that several feed cycles are carried out in succession, since with this system there is practically no time and energy losses for the empty tong return.

The design of the crank mechanism, its arrangement and the connection via the elements mentioned further to the drive means is relatively simple and allows a wide adjustment range of the crank radii and thus the distance between the feed tongs connected to the support slides.

As mentioned, the setting is carried out synchronously, in opposite directions or diverging by means of a common adjusting means, it being one of the essential criteria of the invention that the distance between the support slides or the pliers determines the path length of the forward and return. The adjusting means is arranged between the two crank bearings, into which the adjusting means for the sliders determining the crank radii engage at right angles and coaxially.

Regarding the gearbox already mentioned, it should be noted that this forms an open long side along the rear wall that supports the bearings and two end faces that connect at right angles on both sides, the guideway bearing on two parallel planes being arranged between the end faces.

For a more detailed definition of the drive means, it is noted that it is a drive cylinder for the support slides, which are set at a distance from one another, and can be guided in a stroke-constant sliding manner on a fixedly arranged piston rod.

The support slides must be guided without tilting. In the case of the guideway already proposed, which carries on two parallel planes, the arrangement of a total of eight support rollers, which are in pairs opposite one another, offers reliable guidance.

Compliance with the drive path determined by the stroke is moreover ensured by the fact that the crank wheels are each equipped with two cams which can be directed against a fixed stop formed on the bottom of the gearbox for swiveling or stroke limitation.

As part of the design development, it can be proposed that two switchable and switchable, oppositely directed drive cylinders in the form of working cylinders are arranged between the two parallel strands of the endless drive.

In addition, each feed tongs can be created for yourself on request, which allows the possibility of a possibly desired different feed.

In this context, it is provided as a modification that one of the two sliders, which can be adjusted via a chain wheel and a threaded spindle and determines the crank radius, is designed to be separable from the adjusting means by means of a coupling.

• Figur 1 zeigt das Gerät im Grundriss.
• Figur 2 zeigt den Schnitt I/I durch Fig. 1 im Aufriss.
• Figur 3 zeigt als Ausschnitt aus Fig. 1, geschnitten nach 111/111, die zur Lagefixierungsführung der Kurbelschwingen an den Kurbelscheiben gegebene Ausbildung in vergrösserter Darstellung.
• Figur 4 zeigt den Schnitt II/II durch Fig. 1, ebenfalls im Aufriss, und zwar den gemeinsamen Antrieb der Verstellmechanismen für die Einstellung der Kurbelradien.

The gripper feed device according to the invention is explained in more detail by the attached drawing of an exemplary embodiment.

• Figure 1 shows the device in plan.
• Figure 2 shows the section I / I through Fig. 1 in elevation.
• FIG. 3 shows, as a detail from FIG. 1, sectioned according to 111/111, the design given for the position fixing of the crank arms on the crank disks in an enlarged representation.
• Figure 4 shows the section II / II through Fig. 1, also in elevation, namely the common drive of the adjustment mechanisms for setting the crank radii.

The pliers feed device is arranged in a gear box 2 which is open on one side in its outline and takes over the frame function, wherein between the narrow end walls 2 ', in the area of the open side 2 ", an upper and lower bearing guide track 3 for the two, each with eight support rollers 4' equipped carriage 4, which in turn are each connected to a feed tongs 5, is arranged.

The wall 2 "'opposite this open side 2"' is the carrier of the drive for the adjusting mechanism of the crank radii 13. In the wall 2 "', three neck bearings 6, 7, 6 are arranged parallel to the bottom of the gearbox 2, lying in one plane, at the same distance , wherein the two outer neck bearings 6 are intended for receiving the unit consisting of a chain wheel 8, a shaft 9 and a crank wheel 10, while the middle bearing 7 as a guide for the disengageable adjusting means 12 for common, synchronously running, but oppositely directed The setting of the dimension of the crank radii 13 serves on the two crank wheels 10. The two sprockets 8 are connected by a chain drive, the two runs of this endless drive 14 each being releasably connected to a drive cylinder 15 which is movable on a fixed piston rod 11 and corresponds to the run direction when reaching the preset end position in opposite driving direction is switched.

The adjustment means 12 ends in a bevel gear 16, which in turn, with a preset crank radius 13 and the resulting maximum distance between pliers, in to the axis of the adjustment tels 12 engages bevel gears 17 arranged on all sides, at right angles and coaxially.

In the slide grooves 27 of the crank wheel 10, which are diametrically opposed in this position, the slide pieces 18 provided with thread 19 are arranged such that they can be slidably adjusted in the opposite direction, starting from the threaded spindles 20 connected to the bevel gears 17.

The sliders 18 are each carriers of a crank pivot bearing 21 for the reverse offset to each other, i.e. Deflecting upwards and downwards, pivotally arranged crank arms 23. The other end of the crank arms 23 is also pivotally connected to a slide pivot bearing 22 arranged on each support slide 4.

The design of the feed tongs is subject to change and generally corresponds to known elements of this type. Finite belts 24 can be transported either from right to left or from left to right, depending on which tongs and which transport direction are being controlled. A high feed precision is ensured by fixed stops 25, which are arranged on the bottom of the gearbox 2, and the cams 26, which are each formed on a crank wheel 10.

Claims (9)

1. Gripper feeder for sheet metal strips (24) or profiles for presses, shears, or similar machine tools, having two pairs of feed tongs (5) arranged on the feed side of the press in the direction of adjustment adjustably spaced from one another and reversible drive means (15) connected therewith for the forward and return movement of the feed tongs (5) performable between two strokes of the press, at each stroke imparted by the drive means (15), regardless of the direction of movement, only one of the two pairs of feed tongs (5) being adjusted for conveyance, characterized in that for the conveyance of the strip (24) one carrying slide (4) each of a crankshaft dirve (10/23) led through a common guideway (3) is drivably coordinated to a pair of feed tongs (5) that each crankshaft drive consists of a crank whell (10) with adjustable crank radius (13), a carrying slide (4) for a pair of feed tongs (5), and a crank arm (23) connecting the crank wheel (10) with the carrying slide (4), the crank wheels (10) being arranged on two shafts (9), which at their other ends are provided each with a sprocket wheel (8), both sprocket wheels (8) being connected by an endless drive (14), this being connected to the drive means (15) of reversible travel direction, and that the space between the carrying slides (4) is adjustable by a common means of adjustment (12) for setting the crank radii (13) through their crankshaft (23) connecting the crank swivel bearing (21) and the slide swivel bearing (22) for synchronous, opposite, or divergent motion, thereby determining the path length of the forward and return movements.

2. Gripper feeder according to claim 1, characterized in that the crank wheels (10) are placed in two bearings (6) formed on the rear wall (2"') of a gear box.

3. Gripper feeder according to claim 2, characterized in that the adjusting means (12) is supported in a third bearing (7) arranged centrally between the crank bearings (6) and ends in a bevel gear (16) which, with preadjusted crank radii (13) determining the maximum distance between the two pairs of tongs, engages bevel gears (17) provided with screws (20) and arranged rectangularly and coaxially with respect to the axis of the adjusting means (12), the bevel gears (17) on their turn engaging shoes (18) of in this position diametrically opposed direction provided in slide grooves (27) of the crank wheels (10) and having threads (19) corresponding with the screws (20) and, on actuation of the drive of the bevel gear (16) connected to the adjusting means (12), being, always in opposite direction, slidably adjustable.

4. Gripper feeder according to claims 1 to 4, characterized in that the gear box (2) forms an open longitudinal wall (2") along the rear wall (2"') carrying the bearings (6/7/6) and between the front walls (2') rectangularly connected therewith on both sides, the guideway (3) supporting on two parallel planes being arranged between the front walls (2').

5. Gripper feeder according to claims 1 to 4, characterized in that the drive means for the carrying slides (4) with the space between them adjusted is a drive cylinder guidable in a stationary piston rod (11) so as to slide constant in respect of the strokes.

6. Gripper feeder according to claims 1 to 4, characterized in that each carrying slide (4) is guided on the guideway (3) over idler pulleys (4') engaging the guideway (3) on both sides, and that the swivel slide bearing (22) is formed around an axis extending through the centre of gravity of the slide.

7. Gripper feeder according to claims 2 to 4, characterized in that the crank wheels (10) are provided each with two cams (16) directable against one fixed stop (25) each provided on the bottom of the gear box (2) for swivel and stroke limitation.

8. Gripper feeder according to claim 1, characterized in that between the two parallel strands of the endless drive (14) two oppositely directed drive cylinders (15) in the form of working cylinders are provided that may be switched on and off.

9. Gripper feeder according to claims 1 to 5, characterized in that always one of the shoes (18) adjustable through a sprocket whell (8) and a screw (20), determining the crank radius (13), is formed so as to be separable from the adjusting means (12) by a coupling.

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