Virtual swivel device with movement limitation

A virtual device for the limited pivoting of an object about a base virtual pivot point by means of a pivoting device, where a limiting device is provided for the pivoting angle. The virtual device is a mechanically stable and yet space-saving limiting device that is rotatable about an outer axis on the base and about an outer axis (23′) rotatable on the object, or on the slide, where the limiting device limits the distance and/or the angular position of the two axes relative to one another, with the proviso that the axes always occupy the same plane.

TECHNICAL FIELD

The invention relates to a virtual pivot device with movement limitation of the spherical or hinge movement of an object with respect to a base about a virtual center or a virtual axis.

BACKGROUND

Various devices are known in which an object is pivotable about an axis or spherically about a point stationary with respect to a base, neither the axis nor the point being materially present, but only the storage of the article on arms or the like at the base takes place so that it moves around a point located at a distance therefrom or an axis located at a distance therefrom. Examples are WO2013/029069; WO 2012/123102, corresponding to US 2014/0001318, the content of which is incorporated herein by reference in the jurisdictions in which this is possible.

Examples of such kinematics are, for example, seating furniture, in particular office chairs, bedside tables, operating tables, but also devices for water jet cutting, painting, for carrying milling device, manipulators of all kinds and the like, where it matters that an object as a tool in the broadest sense of Word is pivoted about an operating point and does not change its distance to it. The latter is synonymous with the fact that the tool is guided along a non-planar surface under always the same angle and distance, both and especially at the end of an arm of a robot, which then forms the base disposed.

Such virtual joints are designed, for example, such that an arm is pivotable about a first joint on a base about a first axis, that a second joint is formed on this arm about which a second arm is pivotable, and finally on this second arm, about a third axis of the object (platform) is pivotally mounted with the three axes intersecting at a point, precisely with the pivot point or tools at the operating point.

Another embodiment of such a virtual joint is obtained when a four-bar linkage is rotatably arranged about a first axis, which represents the base, wherein a second four-bar linkage is arranged in the same plane as the first four-bar linkage about one of the two axes which are not articulated thereto and that the object to be rotated (platform) is rotatably mounted on the opposite coupling of this second four-bar linkage.

In both cases it is necessary and by various stops and the like to prevent that the axes take a singular position, namely either coincide or become parallel.

It is now, apart from this compelling need, in many applications, desired or even necessary to limit the extent of rotation around the virtual axis or the virtual item object. The closest solution at first sight to install appropriate stops in the components that form the kinematics, is not always possible because of the apex that occur and the usually compact design of this kinematic device. Since in application areas in which the pivot is not accessible, the rotating around this point object is difficult and is mechanically influenced only in special cases by guides such as scenes and the like, because such an interaction would have to take place in a geometric area, which is only available in a difficult manner, there is a need for a device by which a limitation of the pivoting movement in a simple, reliable, space-saving and robust manner is achieved.

It is the object and task of the invention to indicate such a device.

According to the invention, these goals are achieved by a kinematic limiting device which is fastened on the one hand to the base, on the other hand to the object to be pivoted, on both components about mutually parallel axes and allows a change in distance of the two axes to a predetermined extent. In this way one can achieve a movement of the object about a virtual axis with respect to the base.

In one embodiment, it is provided that the kinematic device also allows a pivoting of the two axes to each other, whereby these always span a plane.

DETAILED DESCRIPTION

In the three views ofFIG. 1a device known from the prior art of technology for the creation of a virtual pivot point can be seen:

The total designated1pivoting device has a base part2, which is hinged about a base axis3rotatably mounted on a base4. On the base part2about an arm axis5an arm6is articulated. In turn, an object carrier8is mounted on this arm6, rotatable about an object axis7. This object carrier8carries the object, not shown. Since the three axes, the base axis3, the arm axis5and the object axis7intersect each other in a single, common point (central point15,FIG. 2), with arbitrary rotation of the base part2, the arm6and the slide8to the each associated axes, the object fixed to the slide object is rotated together with the slide about this point of intersection pivots.

FIGS. 1band 1cshow in different views, the mobility of this kinematic device by which such a pivoting can be achieved within wide limits.

FIG. 2shows a second kinematic pivoting device9, which is not known from the prior art, in which a first base part10is fastened pivotably about an axis3on a base (not shown). This base part10forms with a base arm11and a coupling12a four-bar linkage.

On the base part10at a distance from the axis to which the coupling12is articulated, a further parallel thereto axis is provided, on which an object part13is pivotally articulated. This object part is analogous to the first joint quadrilateral with an object carrier another four-bar linkage.

In this way, theFIG. 2chigh visible axes, a base axis3, an arm axis5and an object axis7are spanned, which in turn intersect each other, as in the first described pivoting device in a central point15. Due to the rotation ability of the entire pivot device9around the base axis3, a spherical movement of the object, which can be rotated (not represented) with the object carrier, is achieved.

FIG. 3shows, in three representations, the possibility of limiting the rotation of the initially mentioned pivot device by providing a pin31in base part2, which cooperates with a curved recess32in arm6and thus the extent of the rotation is limited. In the same way, it is possible to limit the twisting between the base part2and the base4or arm6and the object carrier8. Of course, the pivot and sets can replace the components without a kinematic change. As can be clearly seen fromFIG. 3, this solution is kinematically simple, but because of the short lever arms (distance from the respective axes3,5and7) and the high forces thus occurring is not practical for cases in which the mass of the object and thus the forces are noticeable.

Similar limit stops are possible in the pivoting device according toFIG. 2.

A further limiting device16according to the invention, which does not have these disadvantages, can be seen fromFIG. 4in three variants in a respective perspective view.

FIG. 4ashows a variant of the limiting device16which has or consists of a kinematic link chain17which contains four parts: Namely, two edge parts18,21and two central parts19,20. These four parts are pivotable about three mutually parallel inner axes (without distinction)24against each other. The edge portions18,21are rotatable by means of matching joints or bearings about outer axes23,23′, which are normal to the three inner axes24, at the base or on the object. One of the central parts, in the example shown, the central part19carries a stop22.

The two other variants ofFIG. 4will be explained later, the operation of the limiting device16will be described with reference toFIGS. 5 and 6.

FIG. 5shows, in three illustrations, the pivotability of the limiting device16by fixation of one of the two outer axes, the axis23′ in the space: It is assumed that this axis23′ is suitably rotatably mounted on the base (not shown) of a device equipped according to the invention and the second outer shaft23on the object or the slide (not shown). Now, if the object is rotated about the central point15about an axis parallel to the outer axis23, indicated by the angle A, so the distance between the two axes23,23′; changes by this pivoting movement, as shown in dashed lines. Despite this pivotal movement, the two axes remain parallel to each other and thus span a plane, synonymous with: lie in one plane.

The limiting device16can join in this movement, since the link chain17performs the folding movement illustrated in the secondaryFIGS. 5band 5c, it being only necessary to take care that the shortest distance between the two axes23,23′ is even greater than the corresponding one length of the two outer parts18,21increased by the necessary length of the largely folded central parts19,20. If necessary, the inner axis arrangement of the parts18-21can be achieved by mutually offset arrangement in the direction of an even smaller degree. As can be seen from the cohesion ofFIGS. 5a, b, c, the stop22ensures that the link chain17does not reach its extended position, since it has singularity in this position (all three inner axes in one plane) an loses its function.

FIG. 6shows in three views the situation in a rotated by 90° to this level, it can be seen that in this rotation of the shown inFIG. 4, parallel course of the two outer axes23is no longer met, but this spans a plane (=lie in one plane); and that by this change in angle pivoting about an axis normal to the pivot axis ofFIG. 5ais possible. Despite this rotation by 90°, the maximum distance M, which can be achieved by the stop of the stop22at the associated edge portion18,21results here as well. Since, as can be seen fromFIG. 6a, the edge parts18,21contribute nothing to the Angle B due to their radial arrangement with respect to the central point15, this is smaller than the Angle A.FIGS. 6band 6cshow the view in the direction of Arrows VI which shows in two extreme situations maximum swing on the one hand, strongest shortening on the other hand.

These two movements about the two axis systems can now be combined in the predetermined limits, whereby the spherical movement of the object around the central point15in the limits prescribed by the limiting device16is possible. By appropriate alignment of the outer axes23,23′ in a suitably selected basic position and corresponding inclination in a plane normal to it, it is possible to provide asymmetric pivoting possibilities. With regard to the limiting device16, these are of course symmetrical, but the assembly of the limiting device with respect to the actual pivoting device1(more precisely: The base and the object) suitably oblique or eccentric. Even with a combination of these movements, the two outer axes23,23′ always remain in one plane (=span one plane).

Back toFIG. 4b: Here, the two outer parts18,21are shrunk with their associated inner and outer axes to central parts of universal joints, so that one achieves that in both planes ofFIGS. 5 and 6equal maximum angles A=B are achieved.

FIG. 4cshows a variant in which was dispensed with the two edge parts, the now outer, but for reasons of cohesion still called “inner” axes24are rotatably connected to the base or the object rotatably, which causes a rotation corresponding to that ofFIG. 6awhich can no longer take place, from the spherical movement about a virtual point which has become in this simple manner a pure rotary motion (hinge movement) about a virtual axis passing through the central point15and whose axis is located parallel to the inner axis24.

A variant of the limiting device according to the invention is shown inFIG. 9. It is a kind of slide as a central part19-20, which is connected to inner axes24rotatably connected to edge portions18,21, which in turn carry the outer axes23,23′; a device which kinematically performs the same as that ofFIG. 4a.

If the two inner axes24are replaced by a fixed connection, so that in extreme cases, the edge portions18,21are integrally formed with the respectively associated central part, the axes23,23′ in their distance become variable, but are always kept parallel to each other. Thus, the exact same kinematic effect is achieved as with the device according toFIG. 4c.

FIG. 7shows in six not further differentiated representations, the arrangement and operation of the kinematic device according to the invention, in a chair kinematic effect achieved as with the device ofFIG. 4c. A base25is preferably height adjustable and rotatable, provided at the upper end of a support column26. At the base25, a pivoting device1is provided, the slide supports a seat surface27together with backrest28, so that these two contiguous parts around the virtual central point15can perform a spherical movement. To limit this spherical movement, a limiting device16according to the invention is attached according to the limiting device shown inFIG. 4a. The outer axes23,23′ (actually corresponding sockets or the like) are rotatably mounted on each stationary mandrels of the base25, and the seat area27.

With this simple measure you can reach the apparent fromFIG. 7pivotal movements, on the one hand front-rear, on the other hand left-right.

It should be pointed out here that it is of course possible to achieve by special design of the mounting of the outer axes23a releasable fixation of the movement in one direction, by a suitable limitation or fixation of the mobility of the inner axes24a releasable fixation of the movement the seat27, with respect to the left-right movement. Such releasable fixations are known in the field of office furniture, the slide, the manipulators, and in general the automation, and are available in many different ways, so it need not be discussed in detail here. As a practical reversal of such a releasable fixation connecting one or more of the axes is to be regarded with a drive, which may for example consist of electric motor and transmission, in the form of a belt, etc., and is particularly useful in manipulators.

FIG. 8shows here only in three representations, analogous toFIG. 7, the application of the invention in a manipulator29on which an object30is attached Here, on the one hand, the vertical normal position inFIG. 8ais shown, which according to (by definition) shows the front tilted position inFIG. 8band the (by definition) left tilted position inFIG. 8c. By definition, because it depends on the viewpoint of the observer, in which direction of the object carrier8front and which it is laterally. From the cohesion of the three representations, the mobility and functionality of the limiting device16is clearly shown according to the invention, and shows the space-saving arrangement of this device.

The invention is not limited to the illustrated and described embodiments, but may be variously modified and further developed. Reference has already been made to the possibility of an installation skewed in one or both directions with respect to the internal axes and the outer axes, to provide asymmetric pivoting angles with respect to the base and the object; the formation of the limiting device in the form of the configuration of the outer components21in shape of universal joints was also discussed, as was the embodiment with a hinge joint, and the use of the limiting devices ofFIG. 4corFIG. 9.

By changing the length ratios of the individual members of the link chain17, or their distances from inner axis to inner axis, and the outermost inner axis to the outer axis, it is possible to achieve different effects, in particular the pivotability in different directions form different sizes.

In the description and claims, as is common in this field of technology, the term “axis” is equally applied to the mathematical or technical term and the mechanical design of the necessary elements such as bearings, bushings, shafts, etc.

In the description and claims, the terms “front”, “rear”, “top”, “bottom” and so on are used in the common form and with reference to the article in its usual position of use. That is, in a chair, the back is “back” and the seat “above” the frame, a direction which is transverse to another, essentially means a direction rotated by 90° thereto.

It should also be noted that in the description and the claims, such as “lower range” of a hanger, reactor, filter, building, chair, manipulator, or a device or, more generally, an object, the lower half and in particular the lower quarter of the total height means “lowest area” the lowest quarter and in particular an even smaller part; while “middle range” means the middle third of the total height (width−length). All this information has its usual meaning, applied to the intended position of the object under consideration.

In the description and claims, “substantially” means a deviation of up to 10% of the declared value, if it is physically possible, both downwards and upwards, otherwise only in the sensible direction, for degrees (angle and temperature) ±10° are meant.

For terms such as: “a solvent”, “an axis”, the word “a” or “an” is not to be regarded as a numerical word, but as an indefinite article or as a pronoun, unless the context indicates otherwise.

The term “combination” or “combinations” means, unless otherwise stated, all types of combinations, from two of the constituents concerned to a large number or all of such constituents, the term: “containing” also stands for “consisting of”.

The features and variants specified in the individual embodiments and examples can be freely combined with those of the other examples and embodiments and, in particular, used to characterize the invention in the claims without necessarily provisional accompaniment of the other details of the respective embodiment or the respective example.