The present invention relates to a jig particularly for the positioning of at least one article, with length-adjustable props, with a base part, with a receptacle for the article, the props being arranged between the base part and receptacle and being in each case mounted there in an articulated manner, and with a drive and a control for adjusting the props, according to Patent DE 10 2006 011 823.5.
Such jigs for positioning serve for bringing an article into a desired position and holding it in this. Such an article is often a workpiece which with the aid of the jig is brought into this position and retained there, so that machining, for example by a robot, can then take place. Also, by means of such a jig, the article can, if required, be moved into further positions in which further machining steps can take place. The article may also be a tool which is brought into different positions for the purpose of machining a workpiece.
One possible field of use of a jig for the positioning of articles is, for example, the automobile industry, where, for example, bodies, etc. are machined automatically by means of robots on automatic production lines.
The props are length-adjustable and can be pivoted in space. The movements of the props are generated by drives. Control devices control the movement sequence and the final coordinates of the desired position.
Thus, for example, U.S. Pat. No. 5,272,805 has disclosed a jig for the positioning of an article, which jig has a plate with a plurality of props which are arranged independently of one another and on which a workpiece, which may be composed of a plurality of parts, can be positioned. In the case of the jig, a regulating device is provided, which measures the forces introduced into the props on account of the weight of the article and adjusts the props accordingly, so that the weight of the article can be held, even when, for example, changing external forces act on the article. Two or more of the props can be coupled mechanically to one another, in order to generate a particular movement of the article, while restricting degrees of freedom. The props coupled to one another in this case stand at an angle to one another, so that flexural or torsional moments may act on them. Moreover, the known jig requires a high outlay in terms of cost on account of the control and regulating device. The props have to be equipped with sensors which send suitable signals to the control and regulating device. When articles of greater weight are to be positioned, the rigidity requirements are likewise increased, and a correspondingly more complicated control and regulating device is required. The jig cannot react flexibly to highly diverse requirements and applications, and therefore the possibilities for the use of this jig are relatively limited.
U.S. Pat. No. 5,987,726 has disclosed a jig of the type initially mentioned. This possesses a base plate and a reception plate which are connected to one another by means of props which are of variable length. The individual props are inclined at an angle to one another and can be actuated independently of one another. Here, too, the props are subjected to high flexural and torsional moments, and the control and regulating devices for adjusting the props are complicated.
The object of the invention is to improve further the jig of the type initially mentioned, stability and flexibility for different applications being increased and the production and maintenance costs being reduced.
This object is achieved, according to the invention, by means of the features of patent claim 1.
Accordingly, a jig of the type in question is developed in such a way that at least one pair of props consisting of two props is provided, and in such a way that the two props of the pair of props extend parallel, thus resulting in the form of a parallelogram.
It was recognized, according to the invention, that stability can be improved and even wear-induced maintenance and repair costs can be avoided if a pair of props, which has the form of a parallelogram, is formed in each case from two parallel props. This ensures that, on the one hand, each prop absorbs forces individually, but, on the other hand, each pair of props, considered as a pair of forces, can also absorb a moment.
There are in this case the following possibilities for arranging the drive and control units:
according to a first embodiment, at least one prop of at least one pair of props can be activated for length adjustment by means of a drive and control device.
In this case, according to a further advantageous refinement of the invention, the drive device can be assigned spatially to the at least one prop and can be movable together with the latter. In this case, the drive and control device can form a spatial unit with one another. There is also the possibility, however, that the control device is arranged spatially separately from the drive device, if appropriate is accommodated in a switch cabinet.
The props of the pair of props are mounted movably, that is to say in an articulated manner, on the receptacle side and on the base-part side, so that the adjustment of the article in space can be carried out. However, the receptacle itself is fixedly connected to the receptacle-side end of the pair of props, so that the individual props can pivot about their axis of articulation, but the spatial distance between the axes of articulation is invariable. The receptacle can consequently be moved in all three directions of the spatial coordinate system, and also the angular position of the receptacle with respect to the base part can be adjusted according to requirements. The position of the base part can, of course, also be varied.
According to one embodiment, the base part may be present as a platform, on the top side of which the pair of props is arranged. However, any other form of supporting framework, which allows a spatially defined arrangement of the pair of props, may also be envisaged. For high stability in terms of articles of different size and weight which are to be positioned, it is advantageous if six props are provided, since, as a result, high torsional moments in the props are avoided and tensile and compressive forces predominate. With a view to minimizing the production costs, it is then expedient, in turn, to design these six props as three pairs of props.
A version of the jig according to the invention with three pairs of props, which is advantageous in terms of a compact design, is distinguished in that the base-part-side ends and the receptacle-side ends of the three pairs of props are arranged in each case in the form of an imaginary triangle. With a view to high stability, it is preferable to design the distance between the receptacle-side ends of the three pairs of props so as to be smaller than the distance between the base-part side ends of the three pairs of props, so that the imaginary triangle in the region of the receptacle is smaller than the imaginary triangle in the region of the base part.
The imaginary triangle may, according to the invention, be equilateral.
However, an isosceles design of the imaginary triangle is also possible. This isosceles configuration of the triangle leads, at least in one direction of space, to an even more compact type of construction, since it can have angles smaller than 60°. The space or room requirement can thereby be optimized. This is useful, for example, when the jig for positioning is arranged on a production line, since there is usually little space available here between the robots, conveyor belts, structural parts, etc.
Finally, the imaginary triangle formed by the base-part side ends and the imaginary triangle formed by the receptacle-side ends may be rotated with respect to one another. The base area of the base platform, plus the further structural parts, can thereby be minimized within specific limits. Moreover, a positioning jig can react flexibly to different requirements, in that the angle of rotation between the receptacle-side imaginary triangle and the base-part side imaginary triangle is varied. The smaller the angle of rotation is in this case, the higher the rigidity. Also, rigidity in the horizontal direction and flexural rigidity are increased. Tests have shown that the distribution of the forces to the six props is more uniform in the relatively rotated variant.
In a further advantageous refinement of the jig according to the invention with at least three pairs of props, the base-part-side ends of at least two pairs of props lie opposite one another on the first and second line which run parallel to one another (pivot axes B), and the base-part-side ends of the third pair of props lie on a third line which runs perpendicularly with respect to the first and the second line and which forms the pivot axis (B) of the third pair of props.
With regard to the pairs of props lying opposite one another, two arrangement variants in respect of the base-part-side ends may be provided. On the one hand, the base-part-side ends of the pairs of props lying opposite one another may be at no distance from another in the direction of their parallel bearing axes, so that this may be referred to as a respective symmetry. On the other hand, the base-part-side ends of the pairs of props lying opposite one another could also be at a distance from one another in the direction of their parallel bearing axes, so that an offset arrangement is obtained. Both arrangement variants afford a latitude for space-saving and cost-effective solutions for specific applications, even if the stability requirements in the absorption of torques have to be a little lower.
In this case, to achieve high stability, as in the arrangement in the form of an imaginary triangle too, the receptacle-side ends of the pairs of props may be at a shorter distance from one another than the base-part-side ends of the pairs of props. In this case, for example, the arrangement of the base-part-side ends of the pairs of props could be repeated by their receptacle-side ends, but with shorter distances.
According to a preferred variant, the receptacle-side ends of the two pairs of props lying opposite one another may also form an aligned row on an imaginary line parallel to the bearing axes of the base-part-side ends of the pairs of props lying opposite one another. It is thus possible to provide particularly space-saving receptacles for articles.
These variants may be gathered from claims 15 to 18.
A further advantageous refinement of the invention may be to the effect that the receptacle-side ends of each of the two pairs of props lying opposite one another span at least partially an imaginary line extending parallel to the pivot axis or to the first and the second line of the base-part-side end of the pair of props in each case lying opposite one another; in this case, the receptacle-side ends of the props of the pairs of props lying opposite one another may lie on both sides of the imaginary fourth line, the props of the two pairs of props crossing over the imaginary fourth line.
The stability-increasing variant having the props crossing the imaginary fourth line and also the variant of the aligned row of receptacle-side ends presuppose that there has to be, parallel to the bearing axes, a certain distance between the receptacle-side and the base-part-side ends of a pair of props of the two pairs of props lying opposite one another. If this distance is not present, at least the pairs of props lying opposite one another must be at a distance from one another parallel to the bearing axis.
In the advantageous version in question of the jig according to the invention with two pairs of props lying opposite one another and with one pair of props extending orthogonally thereto, the plate-shaped base part and also the receptacle could be of rectangular design. Circular or elliptical or even arbitrarily shaped receptacles may also be considered as a workpiece carrier or tool carrier.
All the pairs of props of the versions outlined hitherto could be equipped cost-effectively with only one drive and control unit in each case or with at least one drive unit and an associated encoder for detecting the drive position. If, however, a particularly flexible behaviour in terms of position variations and a homogeneous load distribution are to be achieved, then a further variant provides for driving at least two props of a pair of props separately. Preferably, the pair of props with the two separately driven props could be the pair of props extending orthogonally with respect to the two pairs of props lying opposite one another. As a result, for example, a pivoting movement of the receptacle could be brought about, in order to counteract flexural moments which are caused by the article, or a controlled pivoting movement could be exerted on the article as an additional movement possibility. Substantial independence of direction is afforded within a defined movement range.
The next advantageous version of the jig according to the invention is concerned with the design of the base part in the form of a body, on the circumference of which the pair of props or a plurality of pairs of props is or are arranged. In this case, the base part may be in the form of a cube, three side faces of the cube being assigned in each case a pair of props, and these extending approximately orthogonally with respect to one another. As a result, it becomes possible to design the receptacle as a spatial structure, for example as a frame-shaped structural part, and consequently to increase the possibility of using the jig according to the invention according to the most diverse possible requirements in spatial terms and in terms of possible articles. The frame-shaped structural part brings to mind suggestions in the area of motor vehicle technology, where the holding of bumper bars or fenders often presents problems. The pairs of props may also be assigned to more than three sides of the cube. Different receptacles for specific pairs of props and different functional assignments could also be envisaged. While tools are fastened to two pairs of props, the remaining pairs of props may hold a structural part on their common receptacle or on their separate receptacles.
These and further advantageous refinements and improvements of the invention may be gathered from the further subclaims.
The invention and also further advantageous refinements and improvements and further advantages of the invention will be explained and described in more detail with reference to the drawing which illustrates some exemplary embodiments of the invention and in which:
FIGS. 9 to 13 show some variants of the jig according to the invention in a diagrammatic illustration,
FIGS. 1 to 4, 6, 8, 12 to 14 show a jig for the positioning of articles 1 (see, in particular,
The pair of props which are located on the left in
According to the invention, at least one pair of props with two props 2 running parallel is provided. Both the pair of props 5 and the other pairs of props are in the form of a parallelogram. Furthermore, according to the invention, a drive and control unit 6 is provided, in which the drive and control are combined, see, in particular,
Two pivot bearings 8, 9 are provided at the receptacle-side end 7 of the prop 2 (see
Reference is made to
The jig 10 illustrated in
The connection of the props 2 of each pair of props 5, 5a and 5b to the receptacle part 4 takes place in each case via a universal joint 24 which is explained in more detail with reference to
As illustrated above, a pivot bearing 15, 16 is provided at the base-part-side end of the props 2 or of the pair of props 5a for each prop 2, the distance between which pivot bearings corresponds to the distance between the two universal joints 24 at the receptacle-side end 7 of the props 2. The pivot bearings 15, 16 are mounted with their bearing axes such that they are pivotable perpendicularly with respect to the pivot axis 22. The pivot axis 22 in this case lies tangentially on an imaginary circle which extends about the centre point M of the base part 3 and the radius of which is determined by the pivot axis 22. Mounted on the carrier block 21 is a carrier 35 on which the drive and control unit 6 is fastened, so that the drive and control unit 6 can pivot together with the carrier block 21.
It is evident from
It is illustrated further above that the pairs of props in each case span a plane, which planes in each case form a triangle with one another. In this case, the triangle at the base-part-side ends of the pairs of props 5, 5a, 5b is larger than the triangle which the planes at the receptacle-side end of the pairs of props 5, 5a and 5b form with one another. In the illustration and explanation relating to
The first (
The third variant differs from the first variant of the first exemplary embodiment in that the imaginary triangle DB formed by the base-part-side ends 10 and the imaginary triangle DA formed by the receptacle-side ends 7 are rotated with respect to one another, as may be gathered from
In the second exemplary embodiment shown in FIGS. 9 to 11, 10a and 11a, three pairs of props 5 are likewise provided, but the arrangement of the three pairs of props with respect to one another is different from in the first exemplary embodiment. The base-part-side ends 10 of two pairs of props 5 are arranged opposite one another. The third pair of props 5D extends orthogonally with respect to the two opposite pairs of props 5. The variant shown in
In the second exemplary embodiment, too, the receptacle-side end 7 of one pair of props 5 is at a shorter distance F from the other receptacle-side end of the next pair of props 5 than the corresponding base-part-side ends 10 of the pairs of props 5 having the distance E, although this is not illustrated for the sake of clarity.
According to the first and second variants of the second exemplary embodiment which are shown in
In the arrangement according to
In the version according to
The third variant illustrated in
In the third variant of the second exemplary embodiment, the receptacle-side ends 7 of the two opposite pairs of props 5 cross one another, without impairing the range of action of the other pair of props 5 in each case.
The version according to
In the versions of
In order to allow different load absorptions, different positions are assumed. In this case, as shown in the first variant, within a pair of props, an arrangement lying opposite one another may be adopted or, as shown in the second and the third variant, an arrangement of the receptacle-side end 5 lying, offset, opposite the base-part-side end 10. In the second and the third variant of the second exemplary embodiment, therefore, a distance L between the receptacle-side end 7 and the base-part-side end 10 of a pair of props 5 is present, but not in the first variant of the second exemplary embodiment. On the pairs of props lying opposite one another, the distance L may either by designed in each case to have the same amount or to have a different amount on each pair of props, as already indicated above. The same also applies to the distances U, U1 and U2. Furthermore, a distance L between the receptacle-side end and the base-part-side end of a pair of props may also be possible on the third orthogonally arranged pair of props, as illustrated in
The positioner shown by way of example in
Two further configurations of positioners (
Finally,
In conclusion, it may be pointed out that the teaching according to the invention is not restricted to the exemplary embodiments discussed above. On the contrary, the most diverse possible designs of the base parts and receptacles in space-saving polygonal forms or with different spatial dimensions are possible. There are, in principle, also many possibilities afforded in terms of the synchronization of the props 2 and the transmission of force from the drive and control unit 6 to the props 2.
It should be stated, once again, that the base-part-side ends and the receptacle-side ends of the props of a pair of props in each case possess the same distance from one another which is invariable.
Number | Date | Country | Kind |
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10 2006 046 758.2 | Sep 2006 | DE | national |