This invention relates to hemming of a bent edge of one or more preformed metal panels to form a hemmed joint or closed panel, and more particularly to an apparatus, system, and method for robotic roller hemming.
It is known in the art relating to hemming of metal panels that roller hemming apparatus can be used to hem the edges of the metal panels forming automotive parts such as door panels, hood panels, and decklid panels.
Conventionally, a hemming apparatus may be mounted to a multi-axis controllable robot and may include a hem roller carried by a support. The conventional hemming apparatus is adapted for hemming a bent edge portion of a workpiece, such as a door panel, positioned on a hemming die, by rotating the hem roller under pressure along the bent portion. The conventional roller type hemming apparatus can thus be used for continuous hemming along the contour of the edge of the workpiece. This process, however, requires moving the workpiece to the hemming die and positioning the workpiece in the die.
Further, it is known to use a portable hemming die apparatus to hem a vehicle wheelhouse area. Such a portable hemming apparatus includes a hemming die set and may be mounted to a robot arm. The robot arm may then move the hemming die set to a workpiece to hem the workpiece. The hemming die, however, may be heavy and bulky to move. Also, each hemming die is specific to the shape and design of a certain workpiece. Hence, the hemming die must be changed when a different workpiece is introduced into a system.
The present invention provides a robotic roller hemming apparatus, system, and method that utilizes a single roller head for pre-hemming and final hemming that can compensate for various material thicknesses. The apparatus, system, and method requires just one programmed robot path to perform both pre-hemming and final hemming, thereby allowing for pre-hemming and final hemming along one path without the need to remove the roller head from the workpiece. The present apparatus, system, and method further allows for the hemming of a plurality of differently shaped workpieces using a single tooling fixture, and allows for adjustment of the pressure on the roller head to conform with various hemming product requirements.
More particularly, the present invention provides a dual robot system and method in which one robot carries a lightweight anvil and a second robot carries a universal roller hemming head apparatus including a hemming roller for both pre-hemming and final hemming of a workpiece such as a vehicle wheelhouse.
In one embodiment, a robotic roller hemming apparatus in accordance with the invention includes a mounting member having a face for operative connection of the mounting member to a multi-axis controllable robotic arm, and a bracket extending from the face. A tracking roller is mounted on the bracket. A slide plate is operatively connected to the bracket and slidable relative to the bracket. A hemming roller is operatively connected to the slide plate proximate the tracking roller for roller hemming nested metal panels therebetween the hemming and tracking rollers. A slide actuator connects the bracket and the slide plate for moving the hemming roller toward and away from the tracking roller.
The robotic roller hemming apparatus may further include a linkage assembly operatively connected to the mounting member and the hemming roller for pivoting the hemming roller relative to the mounting member, and a pivot actuator for actuating the linkage assembly to pivot the hemming roller. The linkage assembly may include a pivot bar having first and second opposite ends, the pivot bar first end being pivotally connected to the slide plate and the pivot bar second end being operatively connected to the hemming roller; a link bar having first and second opposite ends, the link bar first end being pivotally attached to the pivot bar second end adjacent the hemming roller; and a bell crank arm having first and second opposite ends, the bell crank arm first end being pivotally connected to the link bar second end and the bell crank arm second end being pivotally connected to the pivot actuator. The bell crank arm is pivotally connected to the slide plate intermediate its first and second ends. A stop may be mounted to the slide plate. The stop limits the pivotal movement of the pivot bar.
The pivot actuator may be mounted on the slide plate. The slide actuator may be mounted on the mounting member bracket. The mounting member bracket may include a linear track, and the slide plate is operatively engaged with the linear track and slidable along the linear track. The linear track may include a pair of rails, and the slide plate may include a pair of bearing blocks engaged with the pair of rails.
A dual-robot, robotic roller hemming system in accordance with the invention includes a first multi-axis controllable robotic arm having an end effecter that carries a hemming anvil. The system also includes a second multi-axis controllable robotic arm having a roller hemming head at an end thereof. The roller hemming head includes a tracking roller and a multi-positional hemming roller capable of performing both pre-hemming and final hemming operations. The hemming roller is adjustable between pre-hemming and final hemming positions and cooperable with the tracking roller and anvil to pre-hem and final hem a workpiece. The hemming roller performs pre-hemming and subsequent final hemming of the workpiece sequentially along a single hemming path.
The hemming roller may be positionable about an edge of the workpiece on one side of the workpiece, and the anvil may be positionable adjacent the workpiece about a side opposite the hemming roller. The first robotic arm may include a location unit for positioning the anvil relative to a workpiece. The first robotic arm end effecter may include a robotic tool exchange unit for interchanging the anvil with at least one alternative anvil. The system may also include an anvil storage unit for holding the at least one alternative hemming anvil. The anvil may include an attachment device for temporary attachment of the anvil to the workpiece. The attachment device may include an arrangement of vacuum cups.
The hemming roller may include an indexing feature cooperable with an edge of the anvil that allows for indexing of the hemming roller between pre-hemming and final hemming positions. The roller hemming head may include a servo positioner for adjusting the hemming roller between various pre-hemming and final hemming angular positions relative to the anvil. Alternatively, the roller hemming head may include an actuator for adjusting the hemming roller between various pre-hemming and final hemming angular positions relative to the anvil.
The tracking roller may be engagable with the anvil to aide in guiding the roller hemming head along the anvil. The roller hemming head may include a slide unit for compressing the workpiece and the anvil between the hemming roller and the tracking roller. The slide unit may linearly move the hemming roller to adjust the distance between the hemming roller and the tracking roller.
A method for robotic roller hemming in accordance with the invention includes providing a first multi-axis controllable robotic arm having an end effecter that carries a hemming anvil having a hemming surface and a tracking surface. A second multi-axis controllable robotic arm having a roller hemming head at an end thereof is also provided. The roller hemming head includes a hemming roller adjustable between pre-hemming and final hemming positions and a tracking roller proximate the hemming roller. The first robotic arm is employed to position the anvil hemming surface adjacent a workpiece. The hemming roller is adjusted to the pre-hemming position. The second robotic arm is employed to position the roller hemming head relative to the workpiece and the anvil such that the tracking roller contacts the anvil tracking surface and the hemming roller engages the workpiece. The second robotic arm is employed to move the roller hemming head along the anvil such that the tracking roller follows the anvil tracking surface and the hemming roller pre-hems the workpiece. The hemming roller is adjusted to the final hemming position. The second robotic arm is employed to move the roller hemming head along the anvil such that the tracking roller follows the anvil tracking surface and the hemming roller final hems the workpiece.
After the first robotic arm positions the anvil hemming surface adjacent the workpiece, the anvil may be temporarily attached to the workpiece to stabilize the anvil relative to the workpiece.
A path followed by the hemming roller during pre-hemming may also be followed by the hemming roller during final hemming. In other words, the pre-hemming and final hemming paths may be essentially identical. During final hemming, the hemming roller may follow the hemming path in the same direction of travel as during pre-hemming. Alternatively, the hemming roller may follow the hemming path in a reverse direction relative to a direction of travel followed during pre-hemming.
The roller hemming head may include a slide unit for engaging and disengaging the tracking roller with the anvil tracking surface and the hemming roller with the workpiece. The slide unit may be actuated to engage the tracking roller with the anvil tracking surface and the hemming roller with the workpiece prior to pre-hemming. The slide unit may also be actuated to disengage the tracking roller with the anvil tracking surface and the hemming roller with the workpiece after final hemming.
After the hemming roller final hems the workpiece, the second robotic arm may be employed to move the roller hemming head away from the workpiece, and the first robotic arm may be employed to move the anvil away from the workpiece.
These and other features and advantages of the invention will be more fully understood from the following detailed description of the invention taken together with the accompanying drawings.
In the drawings:
Referring now to the drawings in detail, numeral 10 generally indicates a robotic roller hemming apparatus in accordance with the invention. Turning first to
In a specific embodiment, the robotic roller hemming apparatus 10 may further include a linkage assembly 26 operatively connected to the mounting member 12 and the hemming roller 22 for pivoting the hemming roller relative to the mounting member. A pivot actuator 28 actuates the linkage assembly 26 to pivot the hemming roller 22, thereby adjusting the hemming roller 22 between various pre-hemming and final hemming angular positions relative to a workpiece. The pivot actuator 28 may be pneumatically operated, hydraulically operated, or similar. The linkage assembly 26 may include a pivot bar 30 having first and second opposite ends 32, 34 respectively. The pivot bar first end 32 is pivotally connected to the slide plate 20 and the pivot bar second end 34 is operatively connected to the hemming roller 22. For example, the hemming roller 22 may be rotatably mounted on a mount 36 via an axle 38, and the mount 36 may be connected to the pivot bar 30. A stop 39 may be mounted to the slide plate 20. The stop 39 limits the pivotal movement of the pivot bar 30. The linkage assembly 26 further includes a link bar 40 having first and second opposite ends 42, 44 respectively. The link bar first end 42 is pivotally attached to the pivot bar second end 34 adjacent the hemming roller 22. The linkage assembly 26 also includes a bell crank arm 46 having first and second opposite ends 48, 50 respectively. The bell crank arm first end 48 is pivotally connected to the link bar second end 44. The bell crank arm second end 50 is pivotally connected to the pivot actuator 24. For example, the bell crank arm second end 50 may be pivotally connected to an end of a piston 52 of the pivot actuator 24. The bell crank arm 46 is also pivotally connected to the slide plate 20 intermediate the bell crank arm first and second ends 48, 50. It should be understood, however, that the linkage assembly 26 may have a different mechanical structure for pivoting the hemming roller 22. The hemming roller 22 may be pivoted by other mechanical or electromechanical arrangements. For example, the apparatus 10 may include a servo positioner for adjusting the hemming roller 22 between various pre-hemming and final hemming angular positions.
The pivot actuator 28 may be mounted on the slide plate 20 by a fastener 54 or similar. Therefore, the linkage assembly 26 and pivot actuator 28 remain stationary relative to the slide plate 20 as the slide plate 20 moves relative to the mounting member 12. The slide actuator 24 may be mounted on the mounting member bracket 16. Hence, the slide actuator 24 is fixed relative to the mounting member 12.
The mounting member bracket 16 may include a linear track 56. The slide plate 20 is operatively engaged with the linear track 56 and slidable along the linear track. The linear track 56 may include a pair of rails 58, and the slide plate 20 may include a pair of bearing blocks 60 engaged with the pair of rails 58.
Turning to
With reference to
The robotic roller hemming system 62 also includes a second multi-axis controllable robotic arm 78 has a roller hemming head, such as the roller hemming apparatus 10, at an end thereof. The second robotic arm 78 can manipulate the hemming apparatus 10 to position the hemming roller 22 about an edge of the workpiece 74 on one side of the workpiece, and the anvil 68 may be positionable adjacent the workpiece about a side opposite the hemming roller 22.
The tracking roller 18 is engagable with the anvil 68 to aide in guiding the roller hemming apparatus 10 along the anvil. The slide plate 20 is linearly moveable to adjust the distance between the hemming roller 22 and tracking roller 18, thereby allowing for compression of the workpiece 74 and the anvil 68 between the hemming roller 22 and the tracking roller 18.
With reference now to
The pivot actuator 28 may be activated to adjust the hemming roller 22 into the pre-hemming position. In the pre-hemming position, the hemming roller 22 may be at a 45° angle relative to the edge of the workpiece 74. Alternatively, the hemming roller 22 may pre-hem the workpiece at 30° and 60° angles relative to the workpiece edge. The second robotic arm 78 is employed to position the roller hemming head, such as roller hemming apparatus 10, relative to the workpiece 74 and to the anvil 68 such that the tracking roller 18 contacts the anvil tracking surface 82 and the hemming roller 22 engages the workpiece 74. For example, the slide plate 20 may be actuated to engage the tracking roller 18 with the anvil tracking surface 82 and to engage the hemming roller 22 with the workpiece 74 prior to pre-hemming. The pressure the hemming roller 22 exerts on the workpiece 74 can be adjusted by varying the amount of force exerted on the slide plate 20 by the slide actuator 24.
When the tracking roller 18 and hemming roller 22 are properly engaged, the second robotic arm 78 is employed to move the roller hemming apparatus 10 along the anvil 68 such that the tracking roller 18 follows the anvil tracking surface 82 and the hemming roller 22 pre-hems the workpiece 74. Next, the hemming roller 22 may be adjusted to the final hemming position. In the final hemming position, the hemming roller 22 is at a 90° angle relative to the edge of the workpiece 74. The second robotic arm 78 is then employed to move the roller hemming apparatus 10 along the anvil 68 such that the tracking roller 18 follows the anvil tracking surface 82 and the hemming roller 22 final hems the workpiece 74.
A path followed by the hemming roller 22 during the pre-hemming stroke may also be followed by the hemming roller during final hemming. In other words, the pre-hemming and final hemming paths may be essentially identical. Likewise, the tracking roller 18 may follow the same path along the anvil track surface 82 during pre-hemming and final hemming. Moreover, during final hemming, the hemming roller 22 may follow the hemming path in the same direction of travel as during pre-hemming. In this case, the second robotic arm 78 may move the hemming roller 22 forward during pre-hemming, return the hemming roller 22 to its starting position by generally moving the hemming roller 22 in a reverse direction, and then move the hemming roller 22 forward during final hemming. Further, while moving the hemming roller 22 back to its starting position after pre-hemming, the hemming apparatus 10 may adjust the hemming roller 22 from its pre-hemming angular configuration to its final hemming configuration.
Alternatively, for final hemming, the hemming roller 22 may follow the hemming path in a reverse direction relative to a direction of travel followed during pre-hemming. In this case, the second robotic arm 78 moves the hemming roller 22 forward during pre-hemming from a first location to a second location, and then moves the hemming roller 22 in reverse during final hemming from the second location back to the first location.
After the hemming roller 22 final hems the workpiece 74, the slide plate 20 may be actuated to disengage the tracking roller 18 with the anvil tracking surface 82 and the hemming roller 22 with the workpiece 74 after final hemming. More specifically, the slide actuator 24 moves the slide plate 20 outwardly relative to the mounting member 12 to increase the distance between the tracking roller 18 and hemming roller 22. Finally, the second robotic arm 78 may be employed to move the roller hemming apparatus 10 away from the workpiece 74, and the first robotic arm 64 may be employed to move the anvil 68 away from the workpiece. If the anvil 68 has been temporarily attached to the workpiece 74 by attachment device 72, the attachment devices 72 are deactivated/released prior to the first robotic arm 64 moving the anvil 68.
Although the invention has been described by reference to specific embodiments, it should be understood that numerous changes may be made within the spirit and scope of the inventive concepts described. Accordingly, it is intended that the invention not be limited to the described embodiments, but that it have the full scope defined by the language of the following claims.