Patent Application
20200180918
The invention relates to a manipulator having a carriage movable relative to a beam, a scissor lift mechanism having one end on the carriage, and a grab on the other end of the scissor lift mechanism.
As manipulators, pallet robots are known that are used for moving objects. Objects are for example flat structures such as cardboards, wooden boards and the like. Other objects such as for example Euro pallets, boxes and the like can however also be transferred by a pallet robot of this type.
To move an object, the pallet robot has a grab that is vertically movable on an also movable beam. It is known, for movement of the grab, for a T-shaped beam to be for example mounted on a ceiling of a machine hall or else on a mounting stand, on which beam there is in turn a trolley. For this purpose, open designs are known, such that the known trolleys very quickly accumulate dirt, permit only straight-line travel, and are of cumbersome and voluminous construction.
The object of the invention is to improve a known manipulator with regard to its operation.
This object is achieved by the features of patent claim 1.
According to the invention, a manipulator is provided having a carriage movable relative to a beam, a scissor lift mechanism that has multiple scissor members and a first end on the carriage and a second end on a support plate movable relative to the carriage by the scissor lift mechanism, a grab on the support plate and having at least two guide rods mounted on the support plate and a grab element on a guide rod in each case, in the end region thereof, the spacing between the grab elements is variable, controlled by a drive, and the grab elements are arranged and fastened releasably on their associated guide rod by in each case a coupling element. By controlling the spacing between the grab elements, it is possible to pick up, move and set down again an object that is to be moved. For this purpose, the distance of the grab elements from one another is changed, controlled by a controller. During operation of such manipulators, it may happen that objects of different sizes and dimensions have to be handled. In this case, it is extremely onerous to stock different grabs that are adapted to the different sizes and dimensions, since such grabs are expensive. Furthermore, each time objects of different sizes are to be handled and the sizes thereof differ considerably from one another, it is necessary to exchange the grab that is in operation at the time for another grab that is adapted to the other size of the object. For this purpose, it is necessary to carry out the onerous tasks of disconnecting electrical connections, compressed-air connections and the like, changing the grab and then reconnecting the connections. Such downtime of the manipulator is also expensive, just as the assembly operations required for this work are. By contrast with this, when keeping the same drive, an adaptation of the grab element to different sizes of objects can be carried out by the respective guide rod being releasably fastened on the grab by a coupling element. If for example objects of smaller dimensions are to be handled, a short guide rod comes into consideration. If objects of greater dimensions are to be handled, long guide rods come into consideration. With the short guide rods, it would not be possible for an object of greater dimensions to be picked up. Therefore, a change is required. This change can be easily carried out by the respective guide rod to be changed being moved out of its mounting in the grab, the coupling element released and the previous guide rod removed. Another guide rod is brought into operative connection with the coupling element and this new guide rod is introduced into its mounting in the grab. In this case, the drive elements for changing the guide rod in its position relative to the grab are of course retained. After this change, it is also already possible as before for the grab to continue to be operated, but now it is possible to handle objects of other dimensions.
In a refinement of the invention, two guide rods are arranged and fastened on each grab element (preferably running parallel to one another), and the guide rods are correspondingly mounted on the support plate and are displaceable relative thereto. By the use of two guide rods on each grab element (that means altogether four guide rods in the case of two grab elements aligned parallel to one another), a straight guidance of the grab elements relative to the support plate of the grab takes place, so that canting is effectively avoided. This is important in particular whenever the outer region of the object that is to be moved is not aligned plane-parallel to the surface of the grab elements facing it. As a result of the parallel arrangement of two guide rods, consequently, by reducing the spacing between the two grab elements, the object is received and thereby aligned and can be optimally picked up. Alternatively or in addition to this, it is possible to realize the support plate in a sandwich-type construction, and a support plate fastened on the scissor lift mechanism cannot displaceably change its position relative to the scissor lift mechanism at all, or only slightly. There is no rotation of this support plate relative to the scissor lift mechanism. By contrast with this, there is a further support plate that is arranged at a distance plane-parallel to the support plate arranged on the scissor lift mechanism. These two support plates are connected to one another by a rotationally operative connection, so that the lower support plate can change its position relative to the upper support plate by rotation. On account of this rotation that may for example take place against the force of a spring or else in a controlled drivable manner, for example an object that is standing on a work area at an angle to the surface of the grab elements can nevertheless be picked up by the grab. After this has taken place, the picked-up object can be brought into its desired position by corresponding counter-rotation. As a result, it is possible for objects such as for example wooden boards that are in one disorderly stack to be picked up, aligned and set down in another orderly stack.
In a refinement of the invention, sensors for detecting the position of at least one guide rod relative to the support plate are provided and are arranged on the support plate. By the sensors, at any time the position of the grab elements of the grab can be determined and the picking-up operation for the object can be controlled in dependence on the position determined. The same applies to actuators such as drives (for example electric motors, compressed-air motors, or the like) and means for handling the objects (such as for example vacuum-operated suction cups or the like).
In a refinement of the invention, the ends of the scissor members with that the support plate is arranged and movably fastened on the scissor lift mechanism are connected to a guide carriage, and a guide rail is connected to the support plate and the guide carriage is in operative connection with the guide rail in a slidingly movable manner. As a result, it is possible that the support plate of the grab can move in a defined direction and by a defined amount relative to the scissor lift mechanism. The permissible movement is preferably a linear movement. This makes it possible in particular to compensate for impacts that act on the grab during operation thereof, in particular when picking up objects that are not aligned. As a result, the wear of the grab is minimized. This type of arrangement of the grab on the scissor lift mechanism is advantageously used in connection with the sandwich-type construction of the support plate described above. As a result, it is possible that the grab can perform both a linear movement (in particular of the upper support plate relative to the scissor lift mechanism) and a rotational movement (between the two support plates arranged plane-parallel to one another).
In a refinement of the invention, there are centering means that have the effect that the support plate is aligned in a predetermined position relative to the scissor lift mechanism. In principle, it is conceivable that the ends of the scissor members of the scissor lift mechanism with that the scissor lift mechanism is connected to the grab are connected to the support plate of the grab by fastening points. However, it is only possible here that the scissor members change their inclination angle relative to the support plate during the extending and contracting of the scissor lift mechanism.
As a result, although a centering of the grab relative to the scissor lift mechanism is realized, this is a rigid centering in the sense of a defined predetermination of the position of the grab relative to the scissor lift mechanism. Such a rigid centering has the disadvantage, however that whenever impacts act on the grab or else forces occur when picking up objects that are not aligned relative to the grab elements, the impacts and forces disadvantageously act not only on the grab but also on the scissor lift mechanism and are transferred from the latter to the carriage. In order to prevent this effectively, centering means that have the effect that the support plate is aligned in a predetermined position relative to the scissor lift mechanism are used. This means in other words that the centering means allow that the grab can be moved out of a predetermined position relative to the scissor lift mechanism, but can subsequently resume this predetermined position. Consequently, not only is a relative movement between the scissor lift mechanism and the grab allowed, but it is ensured that, whenever the defined position between the scissor lift mechanism and the grab has been left, this defined position is subsequently resumed.
A manipulator (also referred to as a pallet robot) according to the invention will be described below with reference to an embodiment. The manipulator shown not only represents an embodiment according to the invention but also further essential features of the manipulator that, individually or in combination with one another, contribute to effective operation of this device.
This manipulator 1 comprises multiple components with their individual elements that will be described in detail below.
One component is a beam with a carriage that is present in the upper part of the manipulator 1.
A further component is a grab for handling objects such as, for example, flat structures such as cardboards, wooden boards, Euro pallets and the like. This grab can be seen in the lower part of
A further component is a scissor lift mechanism that connects the upper part of the manipulator 1 to the grab.
These individual components of the manipulator 1 will be described in detail below.
As can be seen in
The longitudinal beam 3 is stationary. It is installed for example under the ceiling of a building, in particular of a factory hall. It is alternatively conceivable for this longitudinal beam to be mounted on stands at at least two points, in particular exactly two points. Particularly advantageous is the arrangement of exactly two stands at the two ends of the longitudinal beam 3, because, in this way, the carriage 2 can travel along the entire intermediate region between these two points. The carriage 2 thus moves horizontally.
Below the carriage 2, for upward and downward (vertical) movement of the grabs arranged below this carriage, there is a scissor lift mechanism 7. The grab can be moved to different heights by this powered scissor lift mechanism 7. By the vertical movement of the grab and the horizontal movement of the carriage 2, objects can be picked up, moved to a different position, and set down again by the grab.
The scissor mechanism 7 is, in a manner known per se, composed of multiple scissor members 8. The ends of two scissor members 8 are secured by rsp pivots 9 to the bottom side of the carriage 2. Rsp pivots 10 mount the ends of two further scissor members 9 on a support plate 11 of the grab. The fastening points 9, 10 make it possible for the angle at which the respective scissor members 8 lie relative to the bottom side of the carriage 2 or the top side of the support plate 11, respectively, to be varied in order to thus be able to vary the height H between the grab and the carriage 2 in targeted fashion.
Arranged below the support plate 11 of the grab is at least one bearing point 12 that receives at least one guide rod 13. A grab element 14 is arranged at the end of the guide rod 13. In one specific embodiment, a total of four bearing points 12 are provided, and in each case two bearing points 12 are assigned to one guide rod 13. This means that two guide rods 13 are provided, and each of the two guide rods 13 are movable and guided in two bearing points 12. Thus, a grab element 14 is mounted at one end of each of the guide rods 13. The two oppositely situated grab elements 14 can, by a controllable drive motor 15 that acts on the guide rods 13, be varied in terms of their spacing A to one another in order to grip an object (by virtue of the spacing A being reduced) and release this object again after it has been set down (by virtue of the spacing A being increased again at least slightly).
The height H of the scissor lift mechanism 7 is varied by an adjusting element 16. The adjusting element 16 secured by a mounting block 17 to the grab. At the end opposite the mounting block 17, the adjusting element 16 is connected to a drive 18. The adjusting element 16 is for example a toothed belt that extends between the drive 18 and the mounting block 17. By actuation of the adjusting element 16 by the drive 18, the height H of the scissor lift mechanism 7 is varied, whereby the inclination angle of the individual scissor members 8 with respect to one another changes in a manner known per se.
An alternative embodiment with regard to the grab is shown in
Instead of movement of the grab elements 14 of the grab by an electrically operated drive motor 15, it is conceivable for the drive or movement of the grab elements 14 to be realized by compressed air. For this purpose, a device 21 for generating compressed air is provided in the carriage 2. In this case, too, the compressed air generated by the device 21 can be transmitted via compressed-air hoses to the grab elements 14. It is likewise conceivable for the compressed air to be transmitted from the device 21 to the grab elements 14 via the interior of the scissor members 8. In this case, too, the connecting points of the scissor members 8 to one another and the fastening points 9, 10 are of sealed design in order to prevent compressed air (or a vacuum) from being able to escape at these locations where movable parts are connected to one another. The two devices 20, 21 may be provided in each case exclusively, such that the grab is operated either only with a vacuum or only with compressed air. It is also conceivable for the grab elements 14 to be operated in a manner controlled by the drive motor 15, and for the suction cups 19 to additionally be provided, such that, in this case, the device 20 for generating a vacuum is also provided in addition to the drive motor 15. In this case, the device 21 for generating compressed air can be omitted. It is furthermore conceivable for the grab elements 14 to be operated by compressed air, such that, in this case, the device 21 for generating compressed air is also provided in addition to the suction cups 19 and the device 20 for generating a vacuum. Since the scissor lift mechanism 7 comprises two sets of scissor members 8, it is conceivable for one set or both sets to be designed and used for the transmission (and storage) of compressed air or for one set or both sets to be designed and used for the transmission (and storage) of a vacuum or for one set to be designed and used for the transmission (and storage) of compressed air and for the other set to be designed and used for the transmission (and storage) of a vacuum.
In order to be able to control the height H between the support plate 11 and the carriage 2 in targeted fashion and pick up an object from a first position, move this object and set this object down again at a second desired position, it is necessary to detect the value of the height H, that is to say the spacing between the carriage 2 and the support plate 11. This detection is performed by a guide rod 22 that coacts with a sensor 23. The sensor 23 is coupled to one of the scissor members 8 such that, during the extension or contraction of the scissor lift mechanism 7, the spacing of the sensor 23 from the guide rod 22 changes, and this change is detected by the sensor 23 and is a measure for the height H. The output value of the sensor 23 is transmitted in wireless or wired fashion to the controller 6 (and possibly to a further control and/or monitoring device outside the manipulator 1). The sensor 23 is coupled by suitable coupling means (not illustrated) at a coupling point K to the scissor member 8 assigned thereto. In this case, the guide rod 22 serves merely for the guided movement of the sensor 23.
It is illustrated in
With regard to the illustration in
Further detail views of the longitudinal beam 3 in interaction with the carriage 2 are illustrated in
It can be seen in
The at least one drive wheel 4 that has already been schematically illustrated in
Depending on the design of the at least one drive wheel 4 (possibly with the aid of the at least one guide wheel 30), it is sufficient for the carriage 2 to be supported, on its movement travel, on the longitudinal beam 3. For the optimum guidance and also the best possible pick-up of objects and movement of objects that have been picked up and are to be moved by the grab, the carriage 2 has at least one supporting wheel 33 that, for example via a shaft 34, is arranged and supported on a base of the carriage 2 (for example of the side part thereof). For picking up loads, the at least one supporting wheel 33 is supported on the lower flange 27. It is of particular significance that the carriage 2 has in each case one supporting wheel 33 in each case approximately in the end region of this carriage, that is to say has a total of four supporting wheels 33. Two of the supporting wheels 33 are thus supported on the lower flange 27 on one side of the center web 25, and the two further supporting wheels 33 are supported on the other side. As an alternative to the four supporting wheels 33 as described above, use may also be made of three supporting wheels (tripod principle).
Alternatively or in addition to the power supply illustrated in
It is illustrated in
The invention will be described briefly once again in other words below:
For the actuation of the grab for the handling of objects, this grab is on a scissor lift mechanism on a carriage (trolley) on a beam. A vertical mobility of the grab is possible via the scissor lift mechanisms.
The use of compressed air has been found to be well suited for the vertical mobility or the actuation of the grab elements of the grab. For this purpose, it is necessary to transmit the compressed air from a compressed-air source to the drive elements via compressed-air lines. However, controlling the compressed air is extremely difficult and the corresponding construction of the compressed-air system is very complex, if the actuation of the actuators by compressed air is intended to be carried out with great precision. This is often required, however, if sensitive objects such as for example cardboard, wooden boards or the like are to be handled.
According to the invention, a grab for handling objects such as for example Euro pallets, boxes or the like is provided, comprising two guide rods of flexible length arranged parallel to one another. Arranged at the end of the guide rods are grab elements, for example plate-like elements. The guide rods are arranged on a support plate and are controlled by drive elements, for example stepping motors. The actuators and sensors required for movement of the guide rods or the grab elements arranged on them are all arranged centrally on the support plate.
The position detection of the grab elements takes place decentrally, so that no external sensors are required in the area of the movement travel of the grab elements.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2017 112 239.7 | Jun 2017 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2018/064636 | 6/4/2018 | WO | 00 |
