Accumulating conveyors, especially for use in the bodywork construction of the automotive industry

Abstract

The invention relates to a conveyor belt, particularly for use in automotive body manufacturing. It demonstrates how the force transmission on a flexible conveyor belt driven continuously in the vertical plane is exerted orthogonally on the conveyor belt surface by means of a toggle joint mechanism, corresponding to the tangent of the pivot angle of the toggle joint links, and can be continuously adjusted or set as required. The toggle joint mechanism interacts with a linearly displaceable frame, which is arranged to be linearly displaceable against the restoring force of a spring element.

Description

[0001] The invention relates to a storage conveyor, in particular for use in the bodywork construction of the automotive industry. State of the art

[0002] Accumulating conveyors are known from DE 20 2004 001 810 U1 and EP 1 999 043 B1, each comprising a circulating, driven traction element, a stationary base frame, and at least one workpiece carrier comprising a load carrier and a pulley. The pulley has at least one upper and at least one lower clamping element, between which the traction element is arranged and by means of which the pulley can be clamped to the traction element. The traction element is a flexible belt, which is driven by a motor in one direction and guided over deflection stations / rollers. The pulley has at least one spring element, which exerts a spring force on at least one clamping element and effects the clamping. In the direction of travel, the workpiece carrier has an actuating element in its front area, which reduces the clamping force if the workpiece carrier approaches a preceding workpiece carrier.

[0003] DE 10 2017 210 160 A1 also describes a storage conveyor in which the clamping force is caused by an eccentric, with a clamping force increasing on a conveyor belt.

[0004] From DE 39 26 755 A1, a conveyor system for transporting workpiece carriers, products, parts, and the like for assembly purposes is known, wherein the workpiece carriers slide or roll along a conveyor track and can be moved away from a conveyor belt by frictional contact and can be stored in the accumulation area by releasing the frictional contact. The underside of the workpiece carriers, along the length of the conveyor track, has pivotable support arms to which a friction plate is attached at its end, such that when the support arms are pivoted, the friction surface of the friction plate is raised or lowered parallel to the driving surface of the conveyor belt, and the support arms are articulated such that the driving of the friction plate in the conveying direction causes the support arms to pivot in the direction of an additional lowering. The friction plate is held on its longitudinal sides by a front and a rear pair of support arms or by several pairs.This increases the frictional contact between the underside of the friction plate and the surface of the conveyor belt when the conveyor belt starts up or when the friction plate is lowered and carried along. Task

[0005] The invention is based on the objective of not only proposing a simple construction for a storage conveyor, but also of providing a defined force-fit connection depending on the application, instead of different and also abrasive clamping forces. Solution

[0006] This problem is solved by the features of claim 1. Some advantages

[0007] In the accumulating conveyor according to the invention, no rolling or abrasive clamping force is generated by a rotary movement. Instead, an adjustable pressure force is provided by a toggle joint mechanism, allowing for precise, essentially stepless control of the pressure force. This can be determined based on the swivel angle, which is limited by the dead center position of the toggle joint mechanism, and depending on the application. In contrast to the prior art, where clamping is achieved by a rotating eccentric, a predetermined pressure force is applied to the flexible conveyor belt by the pressure tabs of the toggle joint mechanism. For example, the pressure tabs of the toggle joint mechanism can be set between 2 degrees and 5 degrees of swivel angle before the dead center position to ensure reliable force transmission.The use of a toggle-lever joint mechanism associated with a linearly guided frame results in a particularly simple design compared to the prior art. The rectilinear movement of the frame requires little space on the workpiece carrier, as no oscillating or lifting movement of the mechanism on a parallelogram guide of a slide, as in the prior art, is required. The frame guidance in the invention can be kept simple, for example, using U-shaped profiles that act like rail guides and effect a linear movement of the frame in a plane. Further inventive embodiments

[0008] Further inventive embodiments are described in the following patent claims 2 to 10.

[0009] A particularly advantageous embodiment is described in claim 2, in which the toggle joint mechanism is associated with two pressure plates that are held apart by a spacer sleeve. The two pressure plates ensure a reliable force-fit connection with the conveyor belt by applying pressure at a predetermined pivot angle. By selecting the pivot angle, the pressure force can be precisely adjusted, achieving a significant ratio between the applied force and the actual pressure force exerted by the pressure plates on the conveyor belt, in certain cases by a ratio of 1:10, 1:16, or 1:20. Since the pressure plates are arranged transversely to the direction of rotation of the conveyor belt, disturbances, including those caused by any protrusions, on the conveyor belt that might move between the pressure plates and the conveyor belt are not a concern.

[0010] A simple construction is described in patent claim 3.

[0011] In the embodiment according to claim 4, the theoretical pressure points of the two pressure tabs on the one hand and the reaction force pressure points acting on the opposite side of the conveyor belt on the other hand are offset from each other by a certain amount, for example by 1 mm to 5 mm, whereby a particularly effective force transmission between the toggle joint mechanism and its pressure tabs and the abutments on the underside of the conveyor belt can be achieved.

[0012] Claim 5 describes a further embodiment in which the pressure tabs have coaxially arranged bores at their end sections facing away from the frame, through which a bolt passes, on which a tab is arranged and which is mounted at its opposite end section on a stationary pivot axis. This results in a compact and stable construction.

[0013] Claim 6 describes an accumulation conveyor in which a stop element projecting from a frame is integrally arranged and interacts with a switchable limiting element to stop the conveying movement of the workpiece carrier. In this way, the movement of one or more workpiece carriers can be stopped even near the end position of the conveying movement, so that the unloader, for example a multi-axis robot, can remove the workpieces from the workpiece carrier. For this purpose, the accumulation conveyor is assigned a switchable limiting element, which, if required, can also be activated in such a way that it projects downwards into the conveying path of the accumulation conveyor. This causes the frame to be displaced when the stop element contacts a limiting element, thereby releasing the frictional connection with the conveyor belt.

[0014] In the embodiment according to claim 7, several such limiting elements are provided as required, which can be controlled one after the other in order to be able to stop the movement of workpiece carriers at predetermined points.

[0015] A particularly advantageous embodiment according to claim 8 is one in which a stop element is assigned to the frame in its longitudinal direction, being continuously or intermittently adjustable and lockable, for example by being screwed on. In this way, the stop element can be adjusted with respect to the limiting element in order to limit the movement of the workpiece carrier at a predetermined point.

[0016] Claim 9 describes a conveyor in which the stop element can be optionally attached to the frame by means of connecting elements, for example, screws. Several such screw holes, arranged in the longitudinal direction of the frame, for example on both sides of the frame, can be provided, to which the stop element can be detachably attached. The screw holes are of the same size and are preferably arranged at equal intervals from each other with respect to their centers on the frame. In this way, the stop element can be detachably attached to the frame intermittently.

[0017] According to claim 10, the limiting element is associated with a controllable force element, for example a linear motor, or a piston-cylinder unit that is alternately pressurized on both sides with compressed air, or an electric motor, which can be switched on and off. These force elements are preferably included in a sequential control system by which the limiting element can be switched on and off with respect to the stop element, so that the workpiece carriers can be stopped at predetermined positions in the movement range of the accumulation conveyor.

[0018] The drawing illustrates the invention – partly schematically – as an example. It shows: Fig. 1. A conveyor belt in side view; Fig. 2 a frame, partly in section, partly in side view; Fig. 3 a frame in top view, partly in section; Fig. 4 a cross-sectional area of ​​the toggle joint mechanism and Fig. 5 another embodiment

[0019] Reference numeral 1 denotes an accumulation conveyor on which numerous workpiece carriers 2 are driven in the X direction by an endless, motor-driven conveyor belt 5. The conveyor belt 5, which may be flexible, is deflected vertically in the area of ​​the reversing stations 3 and 4. A robot can be positioned in the area of ​​the reversing station 4, which removes workpieces, for example, parts for vehicle bodies, from the workpiece carriers 2 and feeds them to the processing stations (not shown).

[0020] If several workpiece carriers 2 collide, the respective workpiece carriers 2 stop. At its opposite end section, a frame 6 is provided with a release head 16, which protrudes from the workpiece carrier 2 in direction X and, upon contact with a preceding workpiece carrier 2, moves the frame 6 linearly in a rail-guided plane against the restoring force of a spring element 11. If a force acts on the release head 16 that exceeds the restoring force of the spring element 11, the frame 6 is displaced in direction T, and the force transmission between the pressure tabs 18 and 19 and the conveyor belt 5 is released, so that the respective workpiece carrier 2 stops, but the conveyor belt 5 continues to run continuously, driven by a motor.

[0021] Each workpiece carrier 2 is associated with such a frame 6, which is guided in a straight line against the restoring force of the spring element 11 by a limited distance in the direction V or T relative to the workpiece carrier 2 via rail-like guide elements 7, 8 or 9, 10. The spring element 11 is under preload, which is adjustable if necessary. At one end, the spring element 11 is connected to the frame 6, in this case by an axle 12, and at its other end is arranged on a fixed abutment 13 associated with the workpiece carrier 2. The axle 12 projects from the frame 6 at opposite ends and has rollers 14, 15 at these ends, which roll smoothly on the rail-like guide elements 9 and 10.If a force acts on the release head 16 that exceeds the restoring force of the spring element 11, the frame 6 is moved in the direction of T and the force transmission between the pressure tabs 18 and 19 and the conveyor belt 5 is released, so that the workpiece carrier 2 in question stops, but the conveyor belt continues to run continuously driven by a motor.

[0022] In the area of ​​the release head 16, a toggle joint mechanism 17 is associated with the frame 6. The toggle joint mechanism 17 consists, among other things, of the two lever-like pressure tabs 18, 19, which are pivotally mounted on an axis 20 in the area of ​​the release head 16. The axis 20 projects from the frame 6 on both sides by a limited amount and has a roller 21, 22 on each of these sections. These rollers roll linearly on the rail-like guide elements 7 and 8, respectively, and run in the same plane as the guide elements 9 and 10, in order to guide the frame 6 in a straight line in one plane. At their end sections opposite the axis 20, the pressure tabs 18 and 19 are each provided with an equally sized, congruent elongated hole 23 and 24, respectively, through which a guide pin 25 passes, which is fixedly mounted.

[0023] The flexible conveyor belt 5 is affected by the Fig. In the position shown in section 2, the pressure tabs 18 and 19 of the toggle joint mechanism 17 engage with their respective end faces 26 and 27 against the surface 28 in a force-fit manner.

[0024] The reaction force is absorbed by fixed abutments 30 and 31 acting against the underside 29 of the conveyor belt 5.

[0025] Axles designated 32 and 33 have a roller 34 and 35 respectively on their outwardly projecting end sections.

[0026] If a force acts on the release head 16 that exceeds the restoring force of the spring element 11, the frame 6 is moved in the direction of T and the frictional connection between the pressure tabs 18 and 19 and the conveyor belt 5 is released, so that the workpiece carrier 2 in question stops, but the conveyor belt 5 continues to run continuously driven by a motor.

[0027] Depending on the position of the pivot angle of the pressure tabs 18, 19, the pressure force on the conveyor belt 5, and thus the frictional connection, can be precisely and continuously adjusted without abrasive wear of the conveyor belt 5, because the pressure tabs 18, 19 exert a pressure force in the direction of the abutments 30 and 31, which absorb the reaction forces. The angular position of the pressure tabs 18 and 19 relative to the frictional connection with the conveyor belt 5 is generally set such that, on the one hand, a reliable frictional connection is achieved, and on the other hand, excessive pressure forces on the conveyor belt 5 are avoided. As a rule, the angle is kept below the dead center position of the toggle joint mechanism 17, for example, 2 degrees to 5 degrees before the dead center position of the pressure tabs 18, 19. Rollers 36 and 37 are also designated. All rollers can be mounted in rolling bearings or in guide bushings.

[0028] In Fig.Figure 5 shows a further embodiment. The pressure tabs 18, 19 do not have elongated holes. Instead, the guide pin 24 is guided through a common bore. A tab 38 is arranged on the guide pin 24, which is fixed in position but pivotable in the direction AB via a pivot axis 39 in the workpiece carrier 2.

[0029] Reference numeral 40 designates a stop element that interacts with a limiting element (not shown) assigned to the base of the accumulation conveyor. When the stop element 40 moves against the switchable limiting element, it causes the frame 6 to be displaced against the restoring force of the spring element. This disengages the toggle joint mechanism 17 from the conveyor belt 5, allowing the conveyor belt 5 to continue moving while the workpiece carrier 2 remains stationary. In this way, one or more workpiece carriers 2 can be stopped in their motion near the end of the accumulation conveyor 1, enabling an unloader, such as a robot, to unload the workpiece carriers 2.A subsequent control mechanism then releases the connection between the stop element 40 and the limiting element, allowing the unloaded workpiece carriers 2 to re-engage with the conveyor belt 5 via the toggle joint mechanism 17 and be conveyed further, i.e., returned to the starting position on the return track for reloading. Subsequent workpiece carriers 2 are also stopped in their conveying motion by running into each other, i.e., by colliding with one another, via the actuating head. This also causes the frame 6 to be moved against the restoring force of the spring element, thereby likewise releasing the frictional connection to the conveyor belt 5 via the toggle joint mechanism 17.

[0030] The features described in the patent claims and in the description, as well as those shown in the drawing, can be essential for the realization of the invention, both individually and in any combination. Reference symbol list 1 Accumulator 2 workpiece carriers 3 Deflection station 4 " 5 Conveyor belt 6 frames 7 Guide element 8 “ 9 10 11 Spring element 12-axis 13 abutments 14 rolls 15" 16 Release head 17 Knee lever joint mechanism 18 Pressure tab 19 " 20 axle 21 roll 22 " 23 Slotted Hole 24 " 25 guide pins 26 Front 27 " 28 surface 29 Underside 30 abutments 31 " 32-axis 33 “ 34 rolls 35" 36" 37 " 38 tab 39 Swivel axis 40 Stop element A Swivel direction BV “Sliding direction, linear” T „ , „ X Direction of flow

Claims

[1] Accumulating conveyor (1), in particular for use in the bodywork construction of the automotive industry, with a flexible conveyor belt (5) guided over deflection stations (3, 4) and continuously driven in one direction by a motor, which forcefully drives workpiece carriers (2) for transporting workpieces, wherein each workpiece carrier (2) has a straight, i.e. linear, for example roller-guided frame (6) by means of rail-like guide elements (7, 8 or 9, 10), to which a toggle joint mechanism (17) is assigned at one end region and one or more pressure tabs (18, 19) of the toggle joint mechanism (17) exert an orthogonal pressure force corresponding to the tangent of the angular position of the respective pressure tabs (18, 19) with respect to the surface (28) of the conveyor belt (5) and the reaction force of this resulting pressure force is absorbed by fixed abutments (30, 31) assigned to the underside (29) of the conveyor belt (5),and the frame (6) is always loaded by a spring element (11) in the direction of the frictional engagement of the toggle joint mechanism (17) with the conveyor belt (5), and the spring element (11) is arranged at one end with the translationally guided frame (6) and at another end on a fixed abutment (13) of the workpiece carrier (2), and the frictional engagement of the toggle joint mechanism (17) with the conveyor belt (5) against the restoring force of the spring element (11) can be released by applying force to a release head (16) pointing in the conveying direction (X) and arranged on the front of the workpiece carrier (2), and / or by a stop element (40) cooperating with a limiting element. [2] Accumulator according to claim 1, characterized by , that the toggle joint mechanism (17) has two spaced-apart pressure tabs (18, 19) which are assigned to the frame (6) on a common axis (20) and which are arranged at a distance from each other by a spacer sleeve. [3] Accumulator according to claim 1 or 2, characterized by , that the pressure tabs (18, 19) of the toggle joint mechanism (17) each have an identical elongated hole (23, 24) at their end section facing away from the frame (6), through which a common, stationary guide pin (25) passes. [4] Conveyor according to claim 1 or any of the following claims, characterized by , that the center point of the guide bolt (25), which passes through the elongated holes (23, 24) of the pressure tabs (18, 19), is offset laterally from the center of the abutments (30, 31) which absorb the reaction forces by a predetermined amount. [5] Accumulator according to claim 1 or 2, characterized by, that the pressure tabs (18, 19) have coaxially arranged bores at their end sections facing away from the frame (6), through which a bolt (25) passes, on which a tab (38) is arranged, which is mounted at its opposite end section on a stationary pivot axis (39). [6] Conveyor according to claim 1 or any of the following claims, characterized by , that a stop element (40) projecting from the frame (6) is integrally assigned to it, which cooperates with a limiting element that can be switched on and off for the purpose of stopping the conveying movement of the workpiece carrier (2). [7] Accumulator according to claim 6, characterized by , that several individually switchable limiting elements are arranged along the conveying path of the accumulating conveyor (1). [8] Accumulator according to claim 6 or 7, characterized by, that the stop element (40) on the frame (6) is continuously or intermittently adjustable and lockable in its longitudinal direction, for example by being screwed on. [9] Conveyor according to claim 6 or one of claims 7 and 8, characterized by , that the frame (6) has holes arranged at a distance from each other on one or both sides, with which the stop element (40) can optionally be detachably fastened by connecting elements, for example screws. [10] Conveyor according to claim 6 or one of the following claims, characterized by that the limiting element can be switched on and off by a controllable force element, for example a linear motor, or a piston-cylinder unit that can be alternately pressurized on both sides with compressed air, or by an electric motor.

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