Patent Application
20190047139
This claims priority from European Application No. 17185997.8, filed on Aug. 11, 2017, the disclosure of which is hereby incorporated by reference in its entirety.
The invention relates to a support rail for a robot platform that is displaceable in a translatory manner, according to the preamble of Claim 1, and to a gantry base for a robot system, according to the preamble of Claim 8. The invention furthermore relates to a displacement system having such a support rail including the robot platform, and to a robot system having such a support rail. The invention moreover relates to methods for the production of a support rail according to the invention.
Generic support rails are known in general from the prior art. These support rails which are sometimes also referred to as the seventh axis or the travel axis, serve the purpose of displacing a conventional industrial robot in a horizontal translatory manner by means of the robot platform that is attached so as to be displaceable in a translatory manner on said support rails. The demand therefor exists in many industrial fields of application, for example in manufacturing when the robot is to be employed at various locations, or in cases in which the robot according to the intended use is to be able to autonomously approach a workpiece storage in order to acquire therein a workpiece to be installed.
Support rails of the generic type are usually fastened to a sub-base by means of a connection flange on the floor, in particular on a shed floor or on a gantry base, by means of which the support rails are positioned significantly above a shed floor or preferably at a height of at least 1.50 m. Support rails of the generic type, on the upper side thereof, usually have two guide rails that run parallel so as to be mutually spaced apart, the wheels of the displaceable robot platform rolling on said guide rails.
Known support rails are configured as completely metallic support rails, in most instances from aluminium or steel. This leads to a comparatively high price of the support rails.
A gantry base of the generic type serves the purpose of providing a support rail of the generic type in an elevated position, preferably at least 1.50 m above a shed floor. There is thus space, for example for further machines, remaining below the support rail and the robot that is displaceable thereon. The use of such a gantry construction mode can also be expedient when the operating steps that are to be carried out by the robot are ideally carried out from above.
It is an object of the invention, in particular for the application in the case of a robot system in a gantry construction mode, to provide a comparatively cost-effective and technically advantageous construction type of a support rail, in particular for use on a gantry base, and a cost-effective and technically advantageous construction type of a gantry base.
A support rail for a robot platform that is displaceable in a translatory manner is proposed according to the invention. Said support rail in a known way is configured in the manner of an elongate construction element that is aligned in a main direction of extent, having at least one metallic guide rail for guiding the robot platform, said metallic guide rail being provided on the external side and extending in the main direction of extent. The support rail in a downwards pointing part-portion has at least one lower metallic connection flange for fastening the support rail to a sub-base such as a shed floor or to a gantry base. Opposite thereto, the support rail in an upwards pointing part-portion, on an external side, has at least one upper metallic connection flange for attaching the metallic guide rail and/or directly the at least one metallic guide rail.
“Down” and “up” in this context relates to the coordinate system of the support rail and does not necessarily mean that the lower connection flange must be aligned towards the floor but in the direction of an attachment face which indeed in most instances is a horizontal floor area, but can also be a gantry base, for example, on which the support rail can be secured by way of a lower connection flange that points to the side or even upwards.
It is provided according to the invention in the case of a support rail of the type described, that said support rail has a support structure of concrete. A metallic tension structure which is under tensile stress in the main direction of extent is provided so as to be embedded in said support structure of concrete. The tension structure extends across at least 60%, preferably across at least 80%, of the length of the support structure.
The metallic tension structure that is embedded in the support structure has been demonstrated to be very advantageous in preventing a robot platform that is displaceable along the support rail, by virtue of the load of said robot platform, from leading to an inacceptably severe flexing. While such flexing is in most cases not to be anticipated in the case of a support rail that by way of floor plates at a minor spacing is provided directly on the floor, a significantly larger spacing between supports such as, for example, columns of the gantry base, is usually provided in the use of support rails on a gantry base, such that the risk of flexing under load mentioned is presently high. The longer the support rail, or the spacing of the supports thereof, respectively, the more expedient the use of a metallic tension structure. A support rail according to the invention preferably in the main direction of extent has a length of at least 3 m, in particular between 4 m and 8 m, particularly preferably of approximately 6 m. The support rail is particularly preferably supported only at the two opposite ends, in particular by the columns of a gantry base.
However, such a deformation is significantly reduced by a tension structure that is under tensile stress. The forces that act externally on the support rail are introduced into the tension structure either by a direct metallic connection between the internal structure and the connection flanges of the support rail, or by way of the support member of concrete. The support structure of concrete per se and/or another part of the support rail are under compressive stress. It is also this compressive stress that reduces the flexing of the support rail. The compressive stress which is introduced into the concrete by the tension structure is preferably sufficiently intense so that the concrete under normal loads at all times remains under compressive stress and is not subjected to tensile stress.
A design in which the support rail additionally has a metallic compression structure that in the main direction of extent is under compressive stress is furthermore possible. It is particularly preferred herein for the compression structure to have an external structure that forms external faces of the support rail, said external structure being particularly preferably formed by a hollow section.
In the case of such a design, a metallic connection exists between the compression structure and the tension structure such that the tensile forces on the tension structure are at least partially equalized by the compressive forces on the compression structure. This metallic connection is preferably provided at the two opposite ends of the support rail. The compression structure can preferably be present in the form of the hollow section mentioned, but instead can also be present in the form of a compression structure that is embedded in the support structure. The external structure in the form of a hollow section that functions as the compression structure, by way of the opposite ends thereof, forms quasi anchor points for the tension structure.
A substantial advantage of such a design having a compression structure lies in that the as yet unfinished support rail in the course of the production does not have to remain in a production tool until the concrete has sufficiently cured in order to be able to sustain the compressive forces that are coupled thereinto by the tension structure.
This comprises designs in which the metallic connection, preferably at the end sides, of the metallic tension structure to the metallic compression structure is provided in a permanent manner. Alternatively however, it can also be provided that the connection between the inboard tension structure and the compression structure exists only temporarily and in the case of an interim product in the course of the production, such that the curing of the concrete can take place outside of a tool that maintains the tensile stress. The connection can then be removed after curing, such that the cured concrete on account thereof is put under compressive stress.
The tension structure can be formed by simple rods of a uniform cross-section that are placed in the main direction of extent and that maintain the stress thereof in a force-fitting manner solely on account of the bonding of the concrete to the external side of the rods.
A design in which the tension structure is configured in such a manner that said tension structure interacts with the support structure of concrete transversely to the main direction of extent, and in relation to the main direction of extent interacts with the support structure of concrete in a form-fitting manner, is advantageous. The regions of the form-fitting interaction between the support structure and the tension structure form quasi anchor points for the tension structure. One possibility therefor lies in that the tension structure at both end sides can be connected to compression plates extended transversely to the main direction of extent. Alternatively or additionally, the tension structure in relation to the main direction of extent can have a variable cross-section, for example on account of transverse struts welded thereto, or of other shapes that impart an anchoring effect.
The support structure of a support rail according to the invention is composed of concrete. It has been demonstrated that concrete has very advantageous properties, in particular damping properties. In order to have low requirements in terms of the complexity of the production, normal construction concrete/cement concrete can be used. However, depending on the requirements, it can also be advantageous for polymer concrete to be used. The stability can be additionally enhanced by additionally incorporating a fibrous material, for example in the form of nets or mats. In this case, the support structure is one from textile concrete.
The invention furthermore relates to a displacement system for a robot, having a support rail having at least one guide rail provided thereon, and a robot platform which is displaceable along the support rail. The support rail herein is configured in the manner as described above.
The invention furthermore also relates to a gantry base of a robot system, for attaching a support rail for a robot platform that is displaceable in a translatory manner. This gantry base has a plurality of vertically extended gantry columns. Said gantry columns have in each case at least one lower metallic connection flange for fastening the gantry columns to a sub-base such as a shed floor, and at least one upper connection flange for attaching a horizontally extended support rail for a robot platform that is displaceable in a translatory manner.
According to the invention it is provided that at least one of the gantry columns has a metallic external structure which is formed by a metallic hollow section. An internal region that is surrounded by this hollow section is at least largely filled with concrete. A metallic internal structure is furthermore embedded in the concrete in the internal region.
Such a gantry column having a metallic internal structure which is embedded in the concrete has proven advantageous in terms of damping properties and stability. The internal structure moreover permits a hollow section having a comparatively minor wall thickness of, for example, at maximum 12 mm or at maximum 8 mm, to be used. The metallic internal structure preferably extends across at least 60% of the length, in particular across at least 80% of the length, of the hollow section.
The metallic internal structure can be embedded completely in the concrete such that each transmission of external force to the internal structure is performed by way of the concrete. A design in which the metallic internal structure is connected directly to the hollow section, preferably by way of a welded connection or a screw connection, is alterntively also possible, however.
In the case of a design having an internal structure that is only placed into the concrete and embedded completely by the latter, the production is performed in that the internal structure is temporarily, and preferably at the ends, positionally fixed relative to the hollow section while the concrete is filled into the hollow section so as to cure therein. This form of temporarily fixing the position can be dispensed with in the case of a direct connection.
The metallic internal structure can have at least one longitudinal segment that is aligned in the main direction of extent, and a plurality of transverse segments which in the transverse direction rise above the longitudinal segment. Said metallic internal structure can also have a plurality of longitudinal segments that are aligned in the main direction of extent and are interconnected by way of transverse segments. An internal structure of this type, having a complex and preferably cage-type geometry, improves the properties of a gantry column that is designed according to the invention.
The invention moreover also relates to a robot system having a gantry base of the type described, and/or a horizontal support rail of the type described, supported by the gantry base. The robot system preferably comprises a robot that is attached to the robot platform.
The invention furthermore relates to methods for the production of a support rail of the type described.
In the case of a first variant of the method for the production of a support rail of the type described above it is provided that at least one lower metallic connection flange and at least one upper metallic connection flange, or a guide rail, respectively, are placed into a formwork or onto the formwork. Furthermore, a tension structure is placed into the formwork and at the end sides secured in a locationally fixed manner to walls of the formwork such that said tension structure is under tensile stress acting in the main direction of extent of the formwork. The formwork is subsequently cast with concrete such that the support structure is formed on account thereof, wherein the tension structure while under tensile stress is embedded in the concrete of the support structure. The support rail produced on account thereof, after the concrete of the support structure has at least partially cured, is removed from the formwork, wherein the tensile stress in the tension structure is at least partially preserved.
It is accordingly provided in the case of such a method that the concrete cures partially or completely before the external tensile force that is applied by the tool is removed and, a compressive stress, in particular by way of the shaping of the tension structure that acts in the manner of an anchor on the support structure, is thus established in the concrete so as to maintain the tensile stress that is directed counter to the former in the tension structure.
In the case of an alternative method for the production of a support rail of the type described, it is provided that a combined metallic tension and compression structure which has at least one structural portion that is under tension in a main direction of extent, and at least one structural portion that is under compression in the main direction of extent is established. A support structure in which at least the structural portion that is under tension is embedded is subsequently cast from concrete.
This method permits the support rail which by virtue of the not yet cured concrete is as yet unfinished to be removed from the tool comparatively early after the support structure has been cast since the support rail by way of the compression structure can maintain the tensile stress in the tension structure in a self-acting manner.
In the case of a particular variant of the method it is provided that a separation of the tension structure from the compression structure is performed after the concrete of the support structure has at least partially cured, wherein the tensile stress in the tension structure is at least partially preserved. In the case of such a procedure, the compression structure supports the tensile stress that exists in the tension structure only in the course of the production. As soon as the concrete has sufficiently cured, the separation mentioned is performed such that the concrete is thus put under compressive stress.
Further advantages and aspects of the invention are derived from the claims and from the description hereunder of preferred exemplary embodiments of the invention which are explained hereunder by means of the figures in which:
The robot system 100 has a displacement system 110 comprising the horizontally aligned support rail 10 mentioned and a platform 120 which on this support rail 10 is displaceable in the main direction of extent A of the support rail 10. The support rail 10, which is again illustrated separately in
By attaching the industrial robot 130 to the platform 120 the robot gains a further degree of freedom which can be utilized, for example, to reach processing locations that are further spaced apart, or to approach a storage so as to pick up components therefrom.
A line bundle 128 (illustrated with dashed lines) which is received in a trough-type channel 22 between the guide rails 42 is provided for supplying the platform 120 and the industrial robot 130.
It is caused on account thereof that the tensile stress prevailing in the tension structure 70 does not have to be entirely and optionally not even largely absorbed by the support structure 20 of concrete, but can be absorbed by the hollow section 84. This is advantageous in the production since no external tool which maintains the tensile stress is blocked. Instead, this can be performed in a self-acting manner by the support rail by way of the end faces 86 thereof.
It is provided in the design according to
The fundamental construction in the case of the alternative design according to
The tension structure in
The manufacturing method for the production of the support rail according to
The starting point of the method is a formwork 300, illustrated in
The compression plates in the manner highlighted by the arrows of
The support rail 10 is removed from the formwork 300 as soon as the concrete has cured. The tensile stress existing in the tie rods 72, in the manner highlighted by the arrows in
Since the support rail of a length of, for example, 3 m by virtue of the gantry construction mode is fundamentally at risk of flexing, the variant described, having a tention structure 70 with tie rods 72, is used.
Like the support rail 10, the gantry columns 210 of the gantry base 200 are also produced as a composite of concrete and metal. The gantry columns 210 have a metallic hollow section 220 which in an internal region is cast from concrete 230, wherein the concrete surrounds a metallic internal structure 240. It has been demonstrated that such a construction having a metallic hollow section and a metallic internal structure as well as a concrete core achieves optimal preconditions for effecting simultaneously the required stability and positive damping properties. Furthermore, the concrete and the metallic internal structure permit the use of hollow sections with comparatively thin walls.
The system of
| Number | Date | Country | Kind |
|---|---|---|---|
| 17185997.8 | Aug 2017 | EP | regional |
